JP5270380B2 - Electric tool, electric tool body, and battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technology capable of inputting/outputting a signal for indicating whether or not a switch is operated and a signal for indicating whether or not the feeding of electric power to a drive part is allowed between a power tool body and a battery pack through a pair of terminals in a power tool. <P>SOLUTION: In the power tool 1, when a main switch SW1 is turned ON, a control voltage Vcc is produced in the body 2 and a logic level of the voltage in the signal terminals 11C, 12C is set to High. When MCU 93 of the battery pack 9 sets the logic level of the voltage in the discharge control signal to High (discharge permission), a transistor Q4 is turned ON and the logic level of the voltage in the signal terminals 11C, 12C is set to Low. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electric tool including a battery pack.

  An example of a conventional electric power tool (see Patent Document 1) is a battery that transmits a control signal indicating whether a switch provided outside the electric power tool main body has been operated from the electric power tool main body via a pair of terminals. It is configured to output to a pack. Further, in this example, a control signal indicating whether or not to allow power supply from the battery pack to the motor of the power tool main body is input from the battery pack to the power tool main body through another pair of terminals. It is configured as follows.

JP 2006-280043 A

  Here, in the above example, in order to input / output the above-described two types of control signals between the power tool body and the battery pack, two pairs of terminals are required. However, in order to simplify the structure of the power tool or improve the degree of freedom in designing the power tool, reducing the number of terminals can be one method.

  Therefore, the present invention provides a power tool that transmits a signal indicating whether or not a switch has been operated and a signal indicating whether or not to permit power supply to the drive unit via a pair of terminals. It is an object of the present invention to provide a technique capable of inputting and outputting between a tool body and a battery pack.

  The power tool according to the first aspect of the present invention made to achieve the above object includes a power tool main body and a battery pack.

  The electric power tool main body is electrically connected to the main body side terminal for inputting / outputting electric signals between the electric power tool main body and the battery pack, and driven by receiving power supplied from the battery back. , A switch for instructing driving and stopping of the driving unit from the outside of the electric tool main body, and a terminal for setting the voltage of the main body side terminal to the first voltage when the driving of the driving unit is commanded by the switch When the voltage setting means and the voltage of the main body side terminal are set to the first voltage, the battery pack and the drive unit are electrically disconnected, while the voltage of the main body side terminal is the first voltage Connection control means for electrically connecting the battery pack and the drive unit when the second voltage is different from each other is provided.

  On the other hand, the battery pack has a battery-side terminal electrically connected to the body-side terminal of the power tool body, and a switch of the power tool body when the voltage of the battery-side terminal is set to the first voltage. The command recognition means for generating a command recognition signal indicating that the drive of the drive unit is commanded, and at least the drive unit from the battery pack based on a predetermined determination procedure including determination of the state of the command recognition signal The permission determination means for determining whether or not to permit the supply of power to the battery and the permission determination means permit the supply of power from the battery pack to the drive unit. Voltage changing means for changing from a voltage to a second voltage.

  In the electric tool configured as described above, when the drive of the drive unit is commanded by the switch, the terminal voltage setting unit of the electric tool main body sets the voltage of the main body side terminal in the electric tool main body to the first voltage. At this time, the connection control means of the power tool main body electrically disconnects the battery pack and the drive unit. On the other hand, when the voltage of the main body side terminal is set to the first voltage, the voltage of the battery terminal in the battery pack that is electrically connected to the main body side terminal is also set to the first voltage. The command recognition means generates a command recognition signal. Then, when the permission determination unit of the battery pack permits the supply of power from the battery pack to the drive unit, the voltage changing unit of the battery pack changes the voltage of the battery side terminal from the first voltage to the second voltage. Let

  When the voltage of the battery side terminal changes to the second voltage, the voltage of the main body side terminal in the power tool main body electrically connected to the battery side terminal also changes to the second voltage. The connection control means electrically connects the battery pack and the drive unit.

  That is, in the electric tool of the first aspect, it is indicated by setting the voltage of the main body side terminal and the voltage of the battery terminal to the first voltage that the drive of the drive unit is commanded by the switch, The fact that the power supply is permitted is indicated by setting the voltage at the main body side terminal and the voltage at the battery terminal to the second voltage.

  Therefore, the electric tool according to the first aspect is configured such that a signal indicating whether or not the switch is operated and a signal indicating whether or not to allow power supply to the drive unit are electrically connected via a pair of terminals. Input / output is possible between the tool body and the battery pack.

  Here, the switch of the electric power tool main body may be configured in any manner for instructing driving and stopping of the driving unit from the outside of the electric power tool main body.

  For example, when the battery pack includes a positive electrode that is electrically connected to the drive unit of the power tool body, the switch turns on / off the electrical connection between the positive electrode of the battery pack and the drive unit of the power tool body. By doing so, you may be comprised so that the drive of a drive part and a stop may be commanded. Further, in this case, the terminal voltage setting means is configured to apply the first voltage to the main body side terminal when the electrical connection between the positive electrode of the battery pack and the drive unit of the electric power tool main body is turned on by the switch. May be.

  In the electric tool configured as described above, when the positive electrode of the battery pack and the drive unit of the electric tool main body are electrically connected, the voltage of the main body side terminal can be set to the first voltage.

  Here, for example, when the electrical connection between the positive electrode of the battery pack and the drive unit of the electric power tool main body is turned on by the switch, the terminal voltage setting unit generates the first voltage from the positive voltage of the battery pack. The generated first voltage may be applied to the main body side terminal.

  In this case, the first voltage is generated only when the positive electrode of the battery pack and the drive unit of the electric power tool body are electrically connected. In other words, since the first voltage is generated only when the drive of the drive unit is commanded by the switch, the voltage of the main body side terminal and the battery side terminal are set even though the drive of the drive unit is not commanded by the switch. Can be prevented from being set to the first voltage.

  The voltage changing means may be configured in any way to change the voltage at the battery side terminal from the first voltage to the second voltage.

  For example, the voltage changing means drops the first voltage or applies a voltage higher than the first voltage to the battery-side terminal, thereby changing the voltage at the battery-side terminal from the first voltage to the second voltage. It may be configured to change.

  In addition, the battery pack may include a sleep mode transition unit that stops the operation of a part of the electronic circuit mounted on the battery pack based on at least the state of the command recognition signal.

  In this case, for example, if the sleep mode transition unit is set so that the sleep mode transition unit operates when the command recognition signal is not generated, the drive unit is instructed to stop by the switch of the electric power tool body. Sometimes, not all the electronic circuits mounted on the battery pack are stopped, but only a part of the electronic circuits are stopped, so that all the electronic circuits are operated after the drive of the drive unit is commanded The drive of the drive unit can be started more quickly.

  In addition, the determination procedure may include any determination in order to determine whether or not to allow power supply from the battery pack to the drive unit.

  For example, when the battery pack includes overcurrent determination means for determining whether or not the magnitude of the current flowing from the battery pack to the power tool main body exceeds a specified current value specified in advance, the determination procedure includes: The determination by an overcurrent determination means may be included.

  In this case, for example, when the magnitude of the current flowing from the battery pack to the power tool main body exceeds a predetermined current value, the permission determination means is set so as not to allow the power supply from the battery pack to the drive unit. If it sets, it can prevent that an excessive electric current flows into a power tool main body from a battery pack, and a malfunction will arise.

  For example, when the battery pack includes an overdischarge determination unit that determines whether or not the battery pack is in an overdischarge state, the determination procedure may include a determination by the overdischarge determination unit. .

  In this case, for example, when the battery pack is in an overdischarged state, if permission determination means is set so as not to permit the supply of power from the batterypack to the drive unit, the power from the battery pack in the overdischarge state to the drive unit Can be prevented from causing problems in the battery pack.

  Further, for example, when the battery pack includes a temperature determination unit that determines whether or not the temperature of the battery pack exceeds a specified temperature that is specified in advance, the determination procedure may include determination by the temperature determination unit. Good.

  In this case, for example, if the permission determination means is set so as not to allow the power supply from the battery pack to the drive unit when the temperature of the battery pack exceeds the specified temperature, It is possible to prevent power from being supplied to the drive unit and causing a problem in the battery pack.

  Moreover, the battery pack may be provided in the electric tool main body so that it cannot be detached, or may be attached to the electric tool main body so as to be removable.

  When the battery pack is detachably attached to the power tool body, the battery pack can be easily replaced.

  Next, the electric power tool main body in the second aspect of the present invention is electrically connected to the main body side terminal for inputting / outputting electric signals between the electric power tool main body and the battery pack, and the battery pack. A drive unit that is driven by receiving power supply from the back, a switch for commanding drive and stop of the drive unit from the outside of the electric power tool body, and when the drive of the drive unit is commanded by the switch, the body side terminal Terminal voltage setting means for setting the first voltage to the first voltage, and electrically disconnecting the battery pack and the drive unit when the voltage of the terminal on the main body side is set to the first voltage, Connection control means for electrically connecting the battery pack and the drive unit when the voltage at the side terminal is set to a second voltage different from the first voltage is provided.

  That is, this electric tool main body is the electric tool main body of the electric tool in the first aspect, and can constitute a part of the electric tool in the first aspect.

  Next, the battery pack according to the third aspect of the present invention is a battery pack for an electric tool that supplies electric power to the electric tool body. And this battery pack, when the voltage of the battery side terminal for inputting and outputting an electric signal between the battery pack and the electric power tool body, and the voltage of the battery side terminal is set to the first voltage, A command recognition means for generating a command recognition signal indicating that driving of a drive unit provided in the electric power tool main body is instructed by a switch provided in the electric power tool main body, and at least determining the state of the command recognition signal As conditions, permission determination means for determining whether or not to permit power supply from the battery pack to the drive unit, and when the supply of power from the battery pack to the drive unit is permitted by the permission determination means, the battery Voltage changing means for changing the voltage of the side terminal from the first voltage to a second voltage different from the first voltage is provided.

  That is, this battery pack is a battery pack of the electric tool in the first aspect, and can constitute a part of the electric tool in the first aspect.

It is a side view of the electric tool in a 1st embodiment. It is a side view which shows a mode that the battery pack was removed from the main body of the electric tool in 1st Embodiment. It is a circuit diagram which shows the structure of the one part electronic circuit mounted in the electric tool in 1st Embodiment. It is a timing chart which shows operation | movement of each part of the electronic circuit in 1st Embodiment. It is a table | surface which shows the operation state of each part of the electronic circuit in 1st Embodiment after a main switch is turned ON until a drive motor starts. It is a table which shows the operation state of each part of the electronic circuit in a 1st embodiment when overcurrent occurs. It is a table which shows the operation state of each part of the electronic circuit in a 1st embodiment when a user recognizes automatic stop mode. It is a flowchart which shows the flow of the discharge control process which MCU in 1st Embodiment performs, Comprising: It is a flowchart which shows from the start to the middle of a discharge control process. It is a flowchart which shows the flow of the discharge control process which MCU in 1st Embodiment performs, Comprising: It is a flowchart which shows the remainder of a discharge control process. It is a circuit diagram which shows the structure of the one part electronic circuit mounted in the electric tool in 2nd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
First, FIG. 1 is a side view of the power tool according to the first embodiment to which the present invention is applied.

  As shown in FIG. 1, the electric power tool 1 of the first embodiment is configured as a so-called driver drill.

  More specifically, the main body 2 of the electric tool 1 includes a motor housing 3, a gear housing 4 positioned in front of the motor housing 3, a drill chuck 5 positioned in front of the gear housing 4, and a lower portion of the motor housing 3. And a handgrip 6 located at the center.

  The motor housing 3 accommodates a driving motor M1 (see FIG. 3) that generates a driving force for driving the drill chuck 5 to rotate.

  The gear housing 4 accommodates a gear mechanism (not shown) that transmits the driving force of the driving motor M <b> 1 to the drill chuck 5.

  The drill chuck 5 includes a mounting mechanism (not shown) that detachably attaches a tool bit (not shown) to the front end of the drill chuck 5.

  The hand grip 6 is formed so that the user of the electric tool 1 can hold the hand grip 6 with one hand. A trigger switch 7 is provided in front of the upper portion of the handgrip 6 for the user of the electric power tool 1 to drive / stop the drive motor M1. A battery pack mounting portion 8 for mounting the battery pack 9 on the main body 2 so as to be detachable is provided at the lower end of the hand grip 6. More specifically, as shown in FIG. 2, the battery pack mounting portion 8 detaches the battery pack 9 from the battery pack mounting portion 8 when the user of the electric power tool 1 slides the battery pack 9 forward. It is configured to be able to. FIG. 2 is a side view showing a state where the battery pack 9 is detached from the main body 2 of the electric power tool 1.

  Next, FIG. 3 is a circuit diagram showing a configuration of a part of electronic circuits mounted on the electric power tool 1.

  As shown in FIG. 3, the main body 2 includes a main switch SW1, a positive terminal 11A, a negative terminal 11B, a signal terminal 11C, a driving circuit 21, and an automatic stop circuit 22.

  The main switch SW1 is interlocked with the trigger switch 7 described above. When the trigger switch 7 is pulled, the main switch SW1 is turned on. When the trigger switch 7 is released, the main switch SW1 is turned off.

  The drive circuit 21 includes the above-described drive motor M1 and a diode D1.

  In the first embodiment, the drive motor M1 is a DC motor with a brush, and one terminal (positive terminal) is connected to the positive power line L1A provided in the main body 2, and the other terminal (negative terminal). Terminal) is connected to the negative power supply line L1B provided in the main body 2. The positive power line L1A is connected to the positive terminal 11A via the main switch SW1.

  The diode D1 is a so-called flywheel diode, and the cathode of the diode D1 is connected to the drive motor so that the spike voltage generated in the drive motor M1 when the current (drive current) flowing to the drive motor M1 is cut off can be removed. The anode of the diode D1 is connected to the negative terminal of the drive motor M1.

  The automatic stop circuit 22 includes a transistor Q1, a resistor R1, a control voltage generation circuit 23, and a signal input / output circuit 24.

  The transistor Q1 is an N channel type MOSFET. The drain and source of the transistor Q1 are inserted into the negative power supply line L1B, while the gate of the transistor Q1 is connected to the collector of a transistor Q2 described later in the signal input / output circuit 24. The negative side power supply line L1B has an end opposite to one end connected to the negative side terminal of the drive motor M1 connected to the negative side terminal 11B. That is, when the transistor Q1 is turned on, the negative electrode side terminal 11B and the negative electrode side terminal of the drive motor M1 are electrically connected. When the transistor Q1 is turned off, the negative electrode side terminal 11B and the negative electrode of the drive motor M1 are connected. The side terminal is electrically disconnected.

  The control voltage generation circuit 23 includes a Zener diode ZD1 and a capacitor C1.

  In the Zener diode ZD1, the cathode of the Zener diode ZD1 is connected to the positive power supply line L1A via the resistor R1, and the anode of the Zener diode ZD1 is connected to the ground (GND) that is the reference potential in the main body 2. ing.

  The capacitor C1 is an electrolytic capacitor, and the positive terminal of the capacitor C1 is connected to the positive power line L1A via the resistor R1 together with the cathode of the Zener diode ZD1, and the negative terminal of the capacitor C1 is the main body 2. Is connected to the ground.

  In the control voltage generation circuit 23 configured as described above, when the main switch SW1 is turned on, a voltage (36 VDC in the first embodiment) applied from the positive power supply line L1A is predetermined by the Zener diode ZD1. The voltage is lowered to a voltage (5 VDC in the first embodiment), and the capacitor C1 is charged with the lowered voltage. The voltage of the capacitor C1 is applied to various circuits as a control voltage Vcc for operating various circuits provided in the main body 2.

  The signal input / output circuit 24 includes a transistor Q2 and resistors R2, R3, R4, and R5.

  In the resistor R2, the control voltage Vcc is applied to one end of the resistor R2, and the other end of the resistor R2 is connected to the signal terminal 11C.

  The transistor Q2 is an NPN type bipolar transistor. The base of the transistor Q2 is connected to the signal terminal 11C through the resistor R3, and is also connected to the ground through the resistor R4. That is, the resistors R2, R3, R4 are connected in series with each other. However, in the first embodiment, when the control voltage Vcc reaches a predetermined voltage and the transistor Q2 is turned on, the resistors R2, R3, and R4 are set so that the voltage at the signal terminal 11C is substantially equal to the control voltage Vcc. The resistance value is set.

  The collector of the transistor Q2 is connected to the gate of the transistor Q1 as described above, while the emitter of the transistor Q2 is connected to the ground in the main body 2.

  In the resistor R5, a control voltage Vcc is applied to one end of the resistor R5, and the other end of the resistor R5 is connected to the collector of the transistor Q2.

  In the automatic stop circuit 22 of the first embodiment, the collector of the transistor Q2 is directly connected to the gate of the transistor Q1 to simplify the description, but the collector of the transistor Q2 switches the transistor Q1. May be connected to the gate of the transistor Q1 through a switching circuit. In this case, a PWM signal having a duty ratio corresponding to the voltage at the collector of the transistor Q2 may be generated by the switching circuit and input to the gate of the transistor Q1.

  On the other hand, the battery pack 9 includes a positive terminal 12A, a negative terminal 12B, a signal terminal 12C, a battery 91, and a battery control circuit 92.

  The positive terminal 12 </ b> A is connected to the positive terminal 11 </ b> A of the main body 2.

  The negative terminal 12B is connected to the negative terminal 11B of the main body 2.

  The signal terminal 12 </ b> C is connected to the signal terminal 11 </ b> C of the main body 2.

  The battery 91 has a positive electrode side terminal 91A and a negative electrode side terminal 91B connected to the positive electrode side terminal 12A and a negative electrode via a positive electrode side power supply line L2A and a negative electrode side power supply line L2B. Each is connected to the side terminal 12B. The battery 91 includes a plurality of battery cells (ten battery cells in the first embodiment), and these battery cells are connected in series between the positive terminal 91A and the negative terminal 91B. That is, in the battery 91, a drive voltage (36VDC in the first embodiment) for driving the drive motor M1 is generated by a plurality of battery cells connected in series. Each battery cell of the first embodiment is a lithium ion secondary battery, and generates a DC voltage of 3.6V.

  The battery control circuit 92 includes a main control unit (MCU) 93, a current measurement circuit 94, a voltage measurement circuit 95, a temperature measurement circuit 96, a switch operation detection circuit 97, and a transistor Q4. Yes.

  The MCU 93 is a well-known microcomputer including at least a CPU, a ROM, a RAM, a rewritable nonvolatile memory, an input / output (I / O) port, and an analog / digital (A / D) converter. It operates according to various programs stored in the built-in ROM of the MCU 93.

  The current measuring circuit 94 is a voltage according to the magnitude of the current flowing out from the positive terminal 91A of the battery 91 or flowing into the positive terminal 91A, or flowing into the negative terminal 91B or out of the negative terminal 91B. An analog current measurement signal having a value is output.

  The voltage measurement circuit 95 is configured to measure the voltage of each battery cell in the battery 91 in order and output an analog voltage measurement signal having a voltage value corresponding to the measured voltage.

  The temperature measurement circuit 96 includes a thermistor and is configured to output an analog temperature measurement signal having a voltage value corresponding to the temperature.

  The switch operation detection circuit 97 includes a transistor Q3 and resistors R6, R7, and R8.

  The transistor Q3 is an NPN bipolar transistor. The base of the transistor Q3 is connected to the signal terminal 12C through the resistor R6, and is also connected to the ground in the battery pack 9 through the resistor R7. In the first embodiment, since the negative power supply line L2B is connected to the ground in the battery pack 9, the ground in the battery pack 9 is at the same potential as the negative power supply line L2B and eventually the negative electrode of the battery 91. ing.

  The collector of the transistor Q3 is connected to the input port of the MCU 93, while the emitter of the transistor Q3 is connected to the ground in the battery pack 9.

  The resistor R8 is applied with a control voltage Vdd (5 VDC in the first embodiment) generated by a voltage generation circuit (not shown) provided in the battery pack 9 at one end of the resistor R8. The other end of R8 is connected to the collector of transistor Q3.

  The transistor Q4 is an N-channel MOSFET, and the gate of the transistor Q4 is connected to the output port of the MCU 93. The drain of the transistor Q4 is connected to the signal terminal 12C, and the source of the transistor Q4 is connected to the ground in the battery pack 9.

  Each part of the electronic circuit in the main body 2 and the battery pack 9 configured as described above operates as shown in FIGS. FIG. 4 is a timing chart showing the operation of each part of the electronic circuit in the main body 2 and the battery pack 9. FIG. 5 is a table showing the operating state of each part of the electronic circuit in the main body 2 and the battery pack 9 from when the main switch SW1 is turned on until the drive motor M1 is started. FIG. 6 is a table showing the operating state of each part of the electronic circuit in the main body 2 and the battery pack 9 when an overcurrent occurs. FIG. 7 is a table showing operation states of the respective parts of the electronic circuit in the main body 2 and the battery pack 9 when the user recognizes the automatic stop mode.

  As shown in FIGS. 4 and 5, when the trigger switch 7 is released and the main switch SW1 is turned off, the operation mode of the MCU 93 is set to the sleep mode. In this sleep mode, the MCU 93 does not stop all the electronic circuits mounted on the MCU 93 but operates a part of the electronic circuits and stands by. That is, the MCU 93 shifts to the sleep mode, thereby reducing the power consumption of the MCU 93 compared to the normal time (normal mode).

  When the trigger switch 7 is pulled and the main switch SW1 is turned on, the control voltage Vcc generated by the control voltage generation circuit 23 increases, reaches a predetermined voltage, and the control voltage Vcc becomes effective. At this time, in order to turn on / off the transistor Q4, the logic level of the voltage in the discharge control signal output from the MCU 93 to the gate of the transistor Q4 is set to Low. For this reason, since the transistor Q4 is OFF, the logic level of the voltage at the signal terminals 11C and 12C is set to High. When the logic level of the voltage at the signal terminals 11C and 12C is set to High, the transistor Q3 of the switch operation detection circuit 97 is turned on, and the voltage in the signal (operation detection signal) input to the MCU 93 from the collector of the transistor Q3 is turned on. The logic level is set to Low. When the logic level of the voltage in the operation detection signal is set from High to Low, the MCU 93 recognizes that the main switch SW1 is turned on, wakes up (starts up) from the sleep mode, and shifts to the normal mode.

  On the other hand, when the logic level of the voltage at the signal terminals 11C and 12C is set to High, the transistor Q2 of the signal input / output circuit 24 is turned on, so that the signal (drive control signal) input to the gate of the transistor Q1. The logic level of the voltage at is low. As a result, the transistor Q1 is turned off, and the drive current supplied from the battery 91 to drive the drive motor M1 is cut off.

  When the MCU 93 recognizes that the main switch SW1 is turned on, the MCU 93 sets the logic level of the voltage in the discharge control signal to High, and permits the discharge from the battery 91 to the drive motor M1. As a result, the transistor Q4 is turned on, the logic level of the voltage at the signal terminals 11C and 12C is set to Low, and the transistor Q2 of the signal input / output circuit 24 is turned off. When the transistor Q2 is turned off, the logic level of the voltage in the drive control signal input to the gate of the transistor Q1 becomes High, so that the transistor Q1 is turned on and the drive motor M1 is started.

  4 and 6, when the MCU 93 recognizes that an overcurrent has occurred after the drive motor M1 is started, the MCU 93 sets the logic level of the voltage in the discharge control signal to Low, and the battery The discharge from 91 to the drive motor M1 is prohibited.

  When the logic level of the voltage in the discharge control signal is set to Low, the transistor Q4 is turned off, and the logic level of the voltage at the signal terminals 11C and 12C is set to High. When the logic level of the voltage at the signal terminals 11C and 12C is set to High, the transistor Q2 in the signal input / output circuit 24 is turned on, so that the logic level of the voltage in the drive control signal becomes Low and the drive motor M1 stops. That is, although the trigger switch 7 is pulled and the main switch SW1 is turned on, the drive motor M1 automatically stops (automatic stop mode).

  As shown in FIGS. 4 and 7, when the user recognizes that the electric power tool 1 has shifted to the automatic stop mode, releases the trigger switch 7, and the main switch SW <b> 1 is turned off, the control voltage generation circuit 23 performs control. Generation of the voltage Vcc is stopped. When the generation of the control voltage Vcc is stopped, the logic level of the voltage at the signal terminals 11C and 12C is set to Low, so that the transistor Q3 in the switch operation detection circuit 97 is turned off. When the transistor Q3 is turned off, the logic level of the voltage in the operation detection signal is set to High. When the logic level of the voltage in the operation detection signal is set to High, the MCU 93 recognizes that the main switch SW1 is turned off.

  When recognizing that the main switch SW1 is turned off, the MCU 93 stands by until the main switch SW1 is turned on.

  Here, if it is recognized that the main switch SW1 is turned on, the logic level of the voltage in the discharge control signal is set to High, and discharge is permitted. On the other hand, if it is not recognized that the main switch SW1 is turned on, it shifts to the sleep mode.

  Here, the processing executed by the MCU 93 to realize the above-described operation will be specifically described.

  8 and 9 are flowcharts showing the flow of discharge control processing executed by the MCU 93. 8 shows from the beginning to the middle of the discharge control process, and FIG. 9 shows the rest of the discharge control process.

  As shown in FIGS. 8 and 9, in this process, first, it is determined whether or not the cancellation of the sleep mode is instructed (S10). More specifically, it is determined whether or not the cancellation of the sleep mode is instructed by determining whether or not the logic level of the voltage in the operation detection signal is set from High to Low.

  If release of the sleep mode has not been instructed (S10: No), it is repeatedly determined whether or not the sleep mode has been released until the release of the sleep mode is instructed.

  On the other hand, when the cancellation of the sleep mode is instructed (S10: Yes), the status check of the MCU 93 and the battery pack 9 is performed (S20). More specifically, the nonvolatile memory built in the MCU 93 is referred to, and the status of the MCU 93 and the battery pack is checked based on various flags indicating the state of the MCU 93 and the state of the battery pack 9.

  When the status check is completed, it is determined whether or not an overcurrent has occurred based on the current measurement signal input from the current measurement circuit 94 (S30), that is, the positive-side power line L2A or the negative-side power line L2B is determined. It is determined whether or not the flowing current exceeds the current value specified in advance. If no overcurrent has occurred (S30: No), based on the voltage measurement signal input from the voltage measurement circuit 95, It is determined whether overdischarge has occurred (S40).

  Here, when an overdischarge has occurred (S40: Yes), the process immediately proceeds to S200 described later, whereas when no overdischarge has occurred (S40: No), an input is made from the temperature measurement circuit 96. Based on the temperature measurement signal to be performed, it is determined whether or not the temperature of the battery pack 9 (battery temperature) exceeds, for example, 80 ° C. (S50).

  When the battery temperature exceeds 80 ° C. (S50: Yes), the process immediately proceeds to S200 described later, whereas when the battery temperature is 80 ° C. or lower (S50: No), based on the operation detection signal. Then, it is determined whether or not the main switch SW1 is turned on (S60).

  When the main switch SW1 is ON (S60: Yes), the logic level of the voltage in the discharge control signal is set to High to permit discharge and set a discharge permission flag indicating that discharge is permitted. (S70). On the other hand, when the main switch SW1 is OFF (S60: No), the process immediately proceeds to S120 described later.

  In S30, if an overcurrent has occurred (S30: Yes), the logic level of the voltage in the discharge control signal is set to Low to prohibit discharge and temporarily indicate that discharge has been suspended. A stop flag is set (S80). Based on the operation detection signal, it is determined whether or not the main switch SW1 is turned on. If the main switch SW1 is turned off (S90: No), the process proceeds to S20 described above, while the main switch SW1 is turned on. If SW1 is ON (S90: Yes), it is determined whether overdischarge has occurred based on the voltage measurement signal (S100). When overdischarge has occurred (S100: Yes), the process proceeds to S200 described later, whereas when overdischarge has not occurred (S100: No), the battery temperature is determined based on the temperature measurement signal. It is determined whether the temperature exceeds 80 ° C. (S110). For example, when the battery temperature exceeds 80 ° C. (S110: Yes), the process proceeds to S200 described later. On the other hand, when the battery temperature is 80 ° C. or less (S110: No), the process proceeds to S80 described above. To do.

  In S120, the logic level of the voltage in the discharge control signal is set to Low to prohibit the discharge and set a discharge stop flag indicating that the discharge is stopped (S120). Then, based on the voltage measurement signal, it is determined whether or not an overdischarge has occurred (S130). If an overdischarge has occurred (S130: Yes), the process proceeds to S200, which will be described later. If no discharge has occurred (S130: No), based on the temperature measurement signal, it is determined whether or not the battery temperature change amount dT / dt is, for example, less than 5 ° C. (S140). Here, when the change amount dT / dt is less than 5 ° C. (S140: Yes), the process proceeds to S230 described later, whereas when the change amount dT / dt is 5 ° C. or more (S140: No). Based on the voltage measurement signal, it is determined whether or not the voltage change amount dV / dt in each battery cell is greater than, for example, −100 mV (S150).

  Here, when the change amount dV / dt is larger than −100 mV (that is, the decrease tendency is small) (S150: Yes), the process proceeds to S230 described later, whereas the change amount dV / dt is −100 mV or less (that is, If the decrease tendency is large) (S150: No), it is determined whether the change amount dV / dt is 0 or less (S160). When the amount of change dV / dt is 0 or less (S160: Yes), that is, when the voltages of all the battery cells are stable, the process proceeds to S20 described above, while the amount of change dV / dt is greater than 0. When it is larger (S160: No), that is, when the voltage of any battery cell is rising, it is determined whether or not the battery temperature is lower than 60 ° C., for example, based on the temperature measurement signal (S170). ).

  When the battery temperature is less than 60 ° C. (S170: Yes), the process proceeds to S20 described above, whereas when the battery temperature exceeds 60 ° C. (S170: No), based on the operation detection signal, It is determined whether or not the main switch SW1 is turned on (S180). If the main switch SW1 is turned on (S180: Yes), the process proceeds to the above-described S20. On the other hand, if the main switch SW1 is turned off (S180: No), the process proceeds to the sleep mode (S190). ), The process proceeds to S10 described above.

  In S200, the logic level of the voltage in the discharge control signal is set to Low to prohibit discharge, and a discharge prohibition flag indicating that discharge is prohibited is set (S200). Then, based on the temperature measurement signal, it is determined whether or not the change amount dT / dt is less than 5 ° C., for example (S210). If the change amount dT / dt is less than 5 ° C. (S210: Yes). On the other hand, when the change amount dT / dt is 5 ° C. or more (S210: No), it is determined whether or not the change amount dV / dt in each battery cell is larger than −100 mV, for example. (S220). If the amount of change dV / dt is greater than −100 mV (that is, the tendency to decrease is small), error processing is executed (S230), and this processing ends. In the error processing of S230, specifically, an abnormality detection flag indicating that an abnormality has been detected is set, and the mode shifts to a charge / discharge inhibition mode in which both charging and discharging are prohibited.

  On the other hand, when the change amount dV / dt is −100 mV or less (that is, the decrease tendency is large) (S220: No), it is determined whether or not the change amount dV / dt is 0 or less (S240). When the change amount dV / dt is 0 or less (S240: Yes), that is, when the voltages of all the battery cells are stable, the process proceeds to S200 described above.

  On the other hand, if the change amount dV / dt is larger than 0 (S240: No), that is, if the voltage of any battery cell is rising, it is determined whether or not the battery temperature is lower than 60 ° C., for example. (S250). When the battery temperature is less than 60 ° C. (S250: Yes), the process proceeds to S200 described above. On the other hand, when the battery temperature is 60 ° C. or higher (S250: No), the process proceeds to the shutdown mode (S260). ), This process is terminated. When the MCU 93 shifts to the shutdown mode, it instructs a circuit (not shown) that turns on / off the power supply to all the electronic circuits mounted in the battery pack 9 to turn off the power supply. , Stop all electronic circuits.

  As described above, in the electric power tool 1 according to the first embodiment, the trigger switch 7 instructs the drive motor M1 to be driven, and the logic level of the voltage at the signal terminal 11C and the logic level of the voltage at the signal terminal 12C. The level is set to High, and the logic level of the voltage at the signal terminal 11C and the logic level of the voltage at the signal terminal 12C are set to Low to indicate that power supply to the drive motor M1 is permitted. I will show you that.

  Therefore, the electric tool 1 transmits a signal indicating whether or not the trigger switch has been operated and a signal indicating whether or not to permit power supply to the drive motor M1 via the pair of signal terminals 11C and 12C. Thus, input / output can be performed between the main body 2 and the battery pack 9.

  Further, in the electric tool 1, the control voltage Vcc is generated only when the positive terminal 12A of the battery pack 9 and the drive motor M1 are electrically connected. That is, since the control voltage Vcc is generated only when the drive of the drive motor M1 is commanded by the trigger switch 7, the drive of the drive motor M1 is not commanded by the trigger switch 7 but at the signal terminal 11C. It is possible to prevent the logical level of the voltage and the logical level of the voltage at the signal terminal 12C from being set to High.

  Further, in the electric power tool 1, the MCU 93 is set to the sleep mode when the battery pack 9 is attached to the main body 2 and the trigger switch 7 is not pulled (that is, the voltage logical level of the operation detection signal is High). Therefore, when the trigger switch 7 is pulled, the drive of the drive motor M1 can be started quickly.

  Moreover, in the electric tool 1, since the discharge to the main body 2 is prohibited when an overcurrent is generated, it is possible to prevent a problem caused by the overcurrent from occurring.

  Further, in the electric power tool 1, when the battery pack 9 is in an overdischarged state, electric power is supplied from the battery pack 9 in the overdischarged state to the drive motor M1 in order to prohibit the discharge to the main body 2. 9 can be prevented from having a problem.

  Further, in the electric power tool 1, when the temperature of the battery pack exceeds 80 ° C., the electric power is supplied from the battery pack 9 having an excessively high temperature to the drive motor M1 in order to prohibit the discharge to the main body 2. It is possible to prevent the battery pack 9 from being defective.

  Moreover, in the electric tool 1, since the battery pack 9 is detachably attached to the main body 2, the battery pack 9 can be easily replaced.

  In the first embodiment, the main body 2 corresponds to the electric power tool main body in the present invention, and the battery pack 9 corresponds to the battery pack in the present invention.

  In the first embodiment, the signal terminal 11C corresponds to the main body side terminal in the present invention, the drive motor M1 corresponds to the drive unit in the present invention, and the trigger switch 7 and the main switch SW1 correspond to the switch in the present invention. The control voltage generation circuit 23 and the signal input / output circuit 24 correspond to terminal voltage setting means in the present invention, and the resistor R1, the signal input / output circuit 24, and the transistor Q1 correspond to connection control means in the present invention.

  In the first embodiment, the signal terminal 12C corresponds to the battery side terminal in the present invention, the switch operation detection circuit 97 corresponds to the command recognition means in the present invention, and the MCU 93 corresponds to the permission determination means in the present invention. The transistor Q4 corresponds to the voltage changing means in the present invention.

In the first embodiment, S180 of the discharge control process executed by the MCU 93 corresponds to the sleep mode transition means in the present invention, and the current measurement circuit 94 and SS30 of the discharge control process correspond to the overcurrent determination means in the present invention. The voltage measurement circuit 95 and the discharge control process S40 correspond to overdischarge determination means in the present invention, and the temperature measurement circuit 96 and the discharge control process S50 correspond to temperature determination means in the present invention.
[Second Embodiment]
Next, a second embodiment will be described.

  The electric power tool in the second embodiment is only partly changed from the electric power tool in the first embodiment.

  Therefore, here, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different components are described.

  FIG. 10 is a circuit diagram showing a configuration of a part of the electronic circuit mounted on the electric power tool 30 in the second embodiment.

  As shown in FIG. 10, the main body 40 includes a main switch SW1, a positive terminal 11A, a negative terminal 11B, a signal terminal 11C, a drive circuit 21, and an automatic stop circuit 25.

  The automatic stop circuit 25 includes a transistor Q1, resistors R1 and R13, a control voltage generation circuit 23, and a signal input / output circuit 26.

  The signal input / output circuit 26 includes a transistor Q5 and resistors R10, R11, and R12.

  The transistor Q5 is an NPN bipolar transistor. The base of the transistor Q5 is connected to the resistor R1 through the resistor R10, and is connected to the ground in the main body 40 through the resistor R11. The emitter of the transistor Q5 is connected to the ground in the main body 40, while the collector of the transistor Q5 is connected to the signal terminal 11C via the resistor R12 and is connected to the transistor via the resistor R12. It is also connected to the gate of Q1.

  In the resistor R13, one end of the resistor R13 is connected to the gate of the transistor Q1, and the other end of the resistor R13 is connected to the source of the transistor Q1.

  On the other hand, the battery pack 50 includes a positive terminal 12A, a negative terminal 12B, a signal terminal 12C, a battery 91, and a battery control circuit 99.

  The battery control circuit 99 includes an MCU 93, a current measurement circuit 94, a voltage measurement circuit 95, a temperature measurement circuit 96, a switch operation detection circuit 100, a transistor Q6, and resistors R14, R17, R18, and R19. ing.

  The switch operation detection circuit 100 includes a transistor Q7 and resistors R15 and R16.

  The transistor Q7 is an N-channel type MOSFET, and the gate of the transistor Q7 is connected to the signal terminal 12C. The drain of the transistor Q7 is connected to the input port of the MCU 93, and the source of the transistor Q7 is connected to the ground in the battery pack 50.

  In the resistor R15, one end of the resistor R15 is connected to the gate of the transistor Q7, and the other end of the resistor R15 is connected to the ground in the battery pack 50.

  In the resistor R16, a control voltage Vdd is applied to one end of the resistor R16, and the other end of the resistor R16 is connected to the drain of the transistor Q7.

  The transistor Q6 is a PNP-type bipolar transistor, and the base of the transistor Q6 is connected to the output port of the MCU 93 via the resistor R17 and is connected to the emitter of the transistor Q6 via the resistor R18. Yes. A control voltage Vdd is applied to the emitter of the transistor Q6, and the collector of the transistor Q6 is connected to the gate of the transistor Q7 via the resistor R19.

  In the resistor R14, a control voltage Vdd is applied to one end of the resistor R14, and the other end of the resistor R14 is connected to the signal terminal 12C.

  In the electronic circuit configured as described above, when the main switch SW1 is turned on, the transistor Q5 of the signal input / output circuit 26 is turned on, and the logic level of the voltage at the signal terminals 11C and 12C is set to Low. At this time, the MCU 93 sets the voltage logic level in the signal (discharge control signal) input to the base of the transistor Q6 to High, turns off the transistor Q6, and inhibits discharge.

  When the logic level of the voltage at the signal terminals 11C and 12C is set to Low, the transistor Q7 of the switch operation detection circuit 100 is turned off, and the logic of the voltage in the signal (operation detection signal) input to the MCU 93 from the drain of the transistor Q7. The level is set to High. When the logic level of the voltage in the operation detection signal is set to High, the MCU 93 recognizes that the main switch SW1 is turned on.

  When recognizing that the main switch SW1 is turned on, the MCU 93 sets the voltage logic level in the discharge control signal to Low, turns on the transistor Q6, and permits discharge.

  When the transistor Q6 is turned on, the logic level of the voltage at the signal terminals 11C and 12C becomes High. As a result, the transistor Q1 is turned ON and the drive motor M1 is started.

  That is, in the second embodiment, when the main switch SW1 is turned on, the logic level of the voltage at the signal terminals 11C and 12C is set to Low and discharge is permitted, contrary to the first embodiment. Contrary to the first embodiment, the logic level of the voltage at the signal terminals 11C and 12C is set to High.

  Since the discharge control process is set so that the MCU 93 matches such a difference, the power tool 30 in the second embodiment exhibits the same effect as the power tool 1 in the first embodiment.

  In the second embodiment, the signal input / output circuit 26 corresponds to the terminal voltage setting means in the present invention, and the signal input / output circuit 26, the transistor Q1, and the resistor R3 correspond to the connection control means in the present invention. To do.

  In the second embodiment, the resistor R14 and the switch operation detection circuit 100 correspond to the command recognition means in the present invention, and the transistor Q6 corresponds to the voltage changing means in the present invention.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various forms can be taken as long as they belong to the technical scope of the present invention.

  For example, in the above embodiment, the present invention is applied to a driver drill, but the present invention may be applied to an electric tool other than the driver drill.

  Moreover, in the said embodiment, although the DC motor with a brush was used as the drive motor M1, a brushless DC motor and an AC motor may be used. However, when a brushless direct current motor or an alternating current motor is used as the drive motor M1, it is necessary to change the drive circuit so that these motors can be driven. Specific changes are well known to those skilled in the art and will not be described here.

  Moreover, although the transistor in the said embodiment was a bipolar transistor or MOSFET, switching elements other than these may be used.

  Moreover, in the said embodiment, although the driver drill was comprised so that a battery pack might be mounted | worn so that removal was possible, you may provide the battery pack so that removal is impossible.

  Moreover, in the said embodiment, although various parameters were set to S50, S110, S140-S170, S210-S250 of discharge control processing, these parameters are only illustrations and the above is according to the specification of an electric tool. Of course, different parameters may be set.

DESCRIPTION OF SYMBOLS 1,30 ... Electric tool, 2,40 ... Main body, 3 ... Motor housing, 4 ... Gear housing, 5 ... Drill chuck, 6 ... Hand grip, 7 ... Trigger switch, 8 ... Battery pack mounting part, 9, 50 ... Battery Pack, 11A, 12A, 91A ... positive terminal, 11B, 12B, 91B ... negative terminal, 11C, 12C ... signal terminal, 21 ... drive circuit, 22, 25 ... automatic stop circuit, 23 ... control voltage generation circuit, 24 , 26 ... signal input / output circuit, 91 ... battery, 92, 99 ... battery control circuit, 93 ... MCU, 94 ... current measurement circuit, 95 ... voltage measurement circuit, 96 ... temperature measurement circuit, 97, 100 ... switch operation detection circuit .

Claims (11)

A power tool body;
Battery pack and
The power tool body is
A body-side terminal for inputting and outputting electrical signals between the power tool body and the battery pack;
A drive unit electrically connected to the battery pack and driven by receiving power from the battery pack ;
A switch for commanding driving and stopping of the driving unit from the outside of the electric power tool body;
A terminal voltage setting means for setting the voltage of the main body side terminal to a first voltage indicating that a command to drive the drive section is issued when driving of the drive section is commanded by the switch;
When the voltage of the main body side terminal is set to the first voltage, the battery pack and the drive unit are electrically disconnected, while the voltage of the main body side terminal is driven from the battery pack to the drive. Connection control for electrically connecting the battery pack and the drive unit when the second voltage different from the first voltage is set , indicating that power supply to the unit is permitted Means and
The battery pack is
A battery side terminal electrically connected to the body side terminal of the power tool body;
Command recognition means for generating a command recognition signal indicating that the drive of the drive unit is commanded by the switch of the power tool main body when the voltage of the battery side terminal is set to the first voltage. When,
Permission determination means for determining whether or not to permit power supply from the battery pack to the drive unit based on a predetermined determination procedure including determination of the state of the command recognition signal;
Voltage changing means for changing the voltage of the battery-side terminal from the first voltage to the second voltage when supply of power from the battery pack to the drive unit is permitted by the permission determination means; A power tool characterized by comprising: The electric tool according to claim 1,
The battery pack includes a positive electrode electrically connected to the drive unit of the electric power tool body,
The switch commands the drive and stop of the drive unit by turning on / off the electrical connection between the positive electrode of the battery pack and the drive unit of the electric power tool body,
The terminal voltage setting means applies the first voltage to the body-side terminal when electrical connection between the positive electrode of the battery pack and the drive unit of the power tool body is turned on by the switch. An electric tool characterized by that. The electric tool according to claim 2,
When the electrical connection between the positive electrode of the battery pack and the drive unit of the electric power tool body is turned on by the switch, the terminal voltage setting unit is configured to determine the first voltage from the positive voltage of the battery pack. A power tool that generates a voltage and applies the generated first voltage to the terminal on the main body side. The electric tool according to any one of claims 1 to 3,
The voltage changing unit drops the first voltage, or applies a voltage higher than the first voltage to the battery-side terminal, so that the voltage of the battery-side terminal is changed from the first voltage to the first voltage. An electric tool characterized by changing to a second voltage. The electric tool according to any one of claims 1 to 4,
The battery pack includes: a sleep mode transition unit that stops operation of a part of the electronic circuit mounted on the battery pack based on at least the state of the command recognition signal. The electric tool according to any one of claims 1 to 5,
The battery pack includes overcurrent determination means for determining whether or not the magnitude of the current flowing from the battery pack to the power tool body exceeds a specified current value specified in advance.
The electric power tool characterized in that the determination procedure includes determination by the overcurrent determination means. The electric tool according to any one of claims 1 to 6,
The battery pack is
Overdischarge determination means for determining whether or not the battery pack is in an overdischarge state,
The electric power tool characterized in that the determination procedure includes determination by the overdischarge determination means. The electric tool according to any one of claims 1 to 7,
The battery pack includes temperature determination means for determining whether or not the temperature of the battery pack exceeds a specified temperature specified in advance.
The electric power tool characterized in that the determination procedure includes determination by the temperature determination means. The electric tool according to any one of claims 1 to 8,
The battery pack is detachably attached to the power tool main body. A power tool body,
A body-side terminal for inputting and outputting electrical signals between the power tool body and the battery pack;
A drive unit electrically connected to the battery pack and driven by receiving power from the battery pack ;
A switch for commanding driving and stopping of the driving unit from the outside of the electric power tool body;
A terminal voltage setting means for setting the voltage of the main body side terminal to a first voltage indicating that a command to drive the drive section is issued when driving of the drive section is commanded by the switch;
When the voltage of the main body side terminal is set to the first voltage, the battery pack and the drive unit are electrically disconnected, while the voltage of the main body side terminal is driven from the battery pack to the drive. Connection control for electrically connecting the battery pack and the drive unit when the second voltage different from the first voltage is set , indicating that power supply to the unit is permitted A power tool body comprising: means. A battery pack for a power tool that supplies power to the power tool body,
A battery-side terminal for inputting and outputting an electric signal between the battery pack and the electric tool body;
A switch provided in the electric tool body when the voltage of the battery side terminal is set to a first voltage indicating that a command for driving a drive unit provided in the electric tool body is issued. by the command recognizing means for generating a command recognition signal indicating that the drive of the drive unit is being commanded,
Permission determination means for determining whether to permit the supply of power from the battery pack to the drive unit, at least using the state of the command recognition signal as a determination condition;
When supply of power from the battery pack to the drive unit is permitted by the permission determination means, the voltage of the battery-side terminal is changed from the first voltage to the drive unit from the battery pack. A battery pack comprising: voltage changing means for changing to a second voltage different from the first voltage , which indicates that the supply is permitted .