JP2002192588A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine capable of realizing prevention of an overload by surely detecting an overload state of a servo motor without depending upon a thermal relay. SOLUTION: Powers are supplied from an AC power source 11 to a plurality of inverters 13a to 13d via a rectifier 12. Servo motors 14a to 14d are respectively connected as loads to the inverters. An electromagnetic contactor 15 is provided between the power source and the rectifier. A first current detector 16 is provided between the rectifier and the inverter. A controller 17 decides an overload state of the motor based on a detected value of the first detector to turn off the contactor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection molding machine,
In particular, the present invention relates to a motor provided as a drive source and an injection molding machine provided with an overload prevention device mainly for preventing overload of a current supply unit thereof.

[0002]

2. Description of the Related Art An electric injection molding machine is usually connected to an AC power supply, and there are various types of loads, such as a motor and a heater, which consume power. In particular, the motor used as the drive source includes a plurality of motors such as an injection servomotor, a screw rotation servomotor in a measuring process, and a mold clamping servomotor. Such a power supply system for supplying power to a plurality of servomotors is realized by a circuit configuration as shown in FIG.

In FIG. 4, a plurality of inverters 43a to 43d are connected in parallel to a three-phase AC power supply 41 via a rectifier 42. Servo motors 44a to 44d as loads are connected to the inverters 43a to 43d, respectively.

In a power supply system having such a circuit configuration, a thermal relay 45 has been used as a measure for preventing overloading of a servomotor and its current supply unit due to overload. As is well known, a thermal relay is a relay that has a built-in bimetal and that interrupts a circuit by utilizing the deformation of the bimetal due to heat caused by an overcurrent state.

[0005]

However, the overload prevention method using a thermal relay has problems such as complicated circuits, susceptibility to ambient temperature, and restrictions on the mounting form of the bimetal. . Further, this overload prevention method does not operate until the overload limit value is exceeded, so that it is not possible to know the state of approaching overload.

On the other hand, there is also a method in which the winding resistance of a servomotor is set to a fixed value, power consumption is obtained from the value and a current value flowing through the servomotor, and an overload state is determined based on the power consumption. However, in this case, there is a problem that the obtained power consumption value has a large error because the winding resistance value fluctuates due to a temperature change.

It is an object of the present invention to provide an injection molding machine capable of detecting an overload state of a servomotor or a current supply unit without using a thermal relay to realize overload prevention.

Another object of the present invention is to provide an injection molding machine having a function of measuring the power consumption or power consumption of a servomotor in addition to preventing overload.

[0009] Still another object of the present invention is to provide an injection molding machine having a function of measuring the total power consumption of all loads connected to an AC power supply and the electricity bill in addition to preventing overload. Is to do.

A further object of the present invention is to provide an injection molding machine having a communication function of transmitting various values obtained by the above functions to an external device such as a computer.

[0011]

According to a first aspect of the present invention, at least one inverter is supplied with power from an AC power supply via a rectifier, and a motor is connected to the inverter as a load. An electromagnetic contactor is provided between the AC power supply and the rectifier, a first current detector is provided between the rectifier and the inverter, and the first current detector is provided. And a controller that determines an overload state of the motor based on the detected value of the motor.

In a first mode, the controller determines the overload state of the motor and controls the electromagnetic contactor.

In the first embodiment, the controller may turn off the electromagnetic contactor when a detection value of the first current detector exceeds a preset limit value.

In the first embodiment, the controller may have a function of outputting a warning display when the detection value of the first current detector approaches a preset limit value. .

According to a second aspect of the present invention, in an injection molding machine having a configuration in which power is supplied from an AC power supply via a rectifier to at least one inverter, and a motor is connected to the inverter as a load. An electromagnetic contactor is provided between the AC power supply and the rectifier, has a function of detecting a first voltage between the rectifier and the inverter, and detects and detects a value detected by the first current detector. Based on the calculated first voltage value, an amount of power consumption integrated for an arbitrary time, an average power consumption per unit time or one molding cycle is calculated, and the calculated values are numerically displayed and a waveform display showing a time-series change. , A controller for controlling a function of outputting for storage and printing or a function of communication.

In a second mode, the controller turns off the electromagnetic contactor when any one of the power consumption and the average power consumption exceeds a preset limit value.

In a second mode, the controller has a function of outputting an alarm for displaying a warning when any one of the power consumption and the average power consumption approaches a preset limit value. You may have it.

In the second embodiment, when another load is branched and connected between the AC power supply and the electromagnetic contactor, a second current detector is connected to a branch line to the another load. The controller has a function of detecting a second voltage between the branch lines, and calculates an electric energy calculated from a detection value of the first current detector and the detected first voltage value. Alternatively, a function of calculating the total power consumption or the average power based on the average power and the power amount or the average power calculated from the detection value of the second current detector and the detected second voltage value is provided. May be.

In the second mode, when another load is branched and connected between the AC power supply and the electromagnetic contactor, a power measuring device is connected to a branch line to the another load, The controller calculates a total power consumption or an average based on a power amount or an average power calculated from a detection value of the first current detector and the detected first voltage value, and a measurement value from the power measurement device. A function for calculating the power may be provided.

In the second mode, the controller further calculates an electric charge from the power consumption integrated over the arbitrary time or the power consumption integrated over the arbitrary time and the total power consumption. May be provided with a controller for controlling a function of outputting numerical values, displaying a waveform indicating a time series change, storing and printing, or a communication function.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. As in the power supply system described with reference to FIG. 4, a plurality of inverters 13 a to 13 d are connected in parallel to a three-phase AC power supply 11 via a rectifier 12. Servo motors 14a to 14d as loads are connected to the inverters 13a to 13d, respectively. The above configuration is the same as the conventional one.

In the present embodiment, the electromagnetic contactor 15 is provided between the AC power supply 11 and the rectifier 12, and the power supply line between the rectifier 12 and each inverter, particularly, the power supply line before being branched in parallel, is provided. One current detector 16 is provided. Further, a controller 17 is provided as control means for turning on and off the electromagnetic contactor 15.

The controller 17 has a function of detecting a first voltage between a power supply line between the rectifier 12 and each inverter, and detects a value detected by the first current detector 16 and a detected first voltage value. Based on this, the power consumption amount integrated for an arbitrary time, the average power consumption per unit time or one molding cycle is calculated. The controller 17 outputs these calculated values for numerical display on a display or for displaying a waveform indicating a time series change, for outputting to a storage device, and for printing with a printer. It has a function of outputting and a function of communicating the calculated value to an external device such as a personal computer or a large computer. The display, storage device, and printer are usually provided on a control panel of the injection molding machine. Of course, the controller 17 can also calculate the electricity rate based on the power consumption described above.

The controller 17 also determines that any one of the detection value of the first current detector 16, the power consumption calculated for an arbitrary time, and the calculated average power consumption exceeds a preset limit value for each. The electromagnetic contactor 15 is turned off.

The controller 17 further determines that any one of the detected value of the first current detector 16, the power consumption calculated for an arbitrary time, and the calculated average power consumption approaches the limit value set in advance for each of them. And output for warning display. This warning is displayed on the display or by an alarm.

Referring to FIG. 2, a second embodiment of the present invention will be described. As in the power supply system described with reference to FIG. 1, a plurality of inverters 13 a to 13 d are connected in parallel to a three-phase AC power supply 11 via a rectifier 12.
Servo motors 14a to 14d as loads are connected to the inverters 13a to 13d, respectively. Also,
An electromagnetic contactor 15 is provided between the AC power supply 11 and the rectifier 12, and a first current detector 16 is provided on a power supply line between the rectifier 12 and each inverter. And
A controller 21 is provided as control means for turning on and off the electromagnetic contactor 15.

In this embodiment, the AC power supply 11 and the electromagnetic contactor 1
It is assumed that another load 22 is branched and connected between the load 5 and the load 5. The load 22 indicates all the power consuming elements (excluding the servo motors 14a to 14d) provided in the injection molding machine, and examples of the power consuming element include a heater disposed in a heating cylinder in which a screw is housed. Can be A second current detector 23 is connected to the branch line to the load 22.
Is connected.

The controller 21 has a function of detecting a first voltage between power supply lines between the rectifier 12 and each inverter, similarly to the controller 17 described with reference to FIG.
Based on the detection value of the first current detector 16 and the detected first voltage value, the power consumption integrated for an arbitrary time, the average power consumption per unit time or one molding cycle is calculated. The controller 21 outputs these calculated values for numerical display on a display, for displaying a waveform indicating a time-series change, for outputting to a storage device, and for printing with a printer. Output. The controller 21 can also calculate the electricity rate based on the above power consumption. Further, the calculated value may be sent to a personal computer or the like via a communication device to perform data management.

The controller 21 also determines that any one of the detected value of the first current detector 16, the power consumption calculated for an arbitrary time, and the calculated average power consumption exceeds a preset limit value for each. The electromagnetic contactor 15 is turned off. The controller 21 further includes a first current detector 1
When any one of the detected value 6, the power consumption calculated for an arbitrary time, and the calculated average power consumption approaches a limit value set in advance for each, an output for warning display is performed.

The controller 21 according to the present embodiment has a function of detecting the second voltage between the branch lines of the load 22 in addition to the above-described functions, and detects the detected value of the first current detector 16 and the detected second voltage. 1 and the power amount or average power calculated from the detected value of the second current detector 23 and the detected second voltage value. Alternatively, it has a function of calculating the total average power.
The controller 21 also calculates an electric charge from the above-described arbitrary-time integrated power consumption or the arbitrary-time integrated power consumption and the total power consumption, and numerically displays the calculated value on a display. Alternatively, it has a function of outputting for displaying a waveform indicating a time series change, outputting for storing in a storage device, or outputting for printing by a printer. The controller 21 further has a function of communicating the calculated value to an external device such as a personal computer.

Referring to FIG. 3, a third embodiment of the present invention will be described. In this embodiment, a power measuring device 32 is provided on a branch line to the load 22 in the second embodiment described with reference to FIG.

Therefore, the controller 3 in the present embodiment
1 has a function of detecting a first voltage between power supply lines between the rectifier 12 and each inverter, similarly to the controller 21 described with reference to FIG. Based on the detected first voltage value, an amount of power consumption integrated for an arbitrary time, an average power consumption per unit time or one molding cycle is calculated. The controller 31 outputs these calculated values for numerical display on a display or for displaying a waveform indicating a time-series change, for output to be stored in a storage device, and for printing by a printer. Output. The controller 31 also has a function of communicating the calculated value to an external device such as a personal computer or a large computer. Controller 3
1 can also calculate the electricity rate based on the above power consumption.

The controller 31 also determines that any one of the detected value of the first current detector 16, the power consumption calculated for an arbitrary time, and the calculated average power consumption exceeds a preset limit value for each. The electromagnetic contactor 15 is turned off. The controller 31 further includes a first current detector 1
When any one of the detected value 6, the power consumption calculated for an arbitrary time, and the calculated average power consumption approaches a limit value set in advance for each, an output for warning display is performed.

The controller 31 according to the present embodiment has, in addition to the above functions, a power amount or an average power calculated from the detected value of the first current detector 16 and the detected first voltage value, and a power measuring device. It has a function of calculating the total power consumption or the total average power from the power amount or the average power measured at 32. The controller 31 also calculates an electric charge from the above-described arbitrary-time integrated power consumption or the arbitrary-time integrated power consumption and the total power consumption, and numerically displays the calculated value on a display. Alternatively, it has a function of outputting for displaying a waveform indicating a time series change, outputting for storing in a storage device, or outputting for printing by a printer. The controller 31 further has a function of communicating the calculated value to an external device such as a personal computer.

In each of the first to third embodiments, the first current detector 16 is connected to the power line between the rectifier 12 and each inverter, particularly, the power line before being branched in parallel. Is provided. In this case, the current detection value by the first current detector 16 is the value of the plurality of servomotors 14a
Since it is the sum of the current values of .about.14d, it is difficult to determine which overload state has occurred in any of the servomotors. On the other hand, by providing a current detector individually for each inverter, that is, on a power supply line after branching in parallel and sending each detection value to the controller, the overload state of the plurality of servomotors 14a to 14d is reduced. Can be individually determined, and the power consumption and the power consumption can also be calculated individually.

[0036]

According to the present invention, the complexity of the circuit due to the thermal relay used for preventing overload, the influence of the ambient temperature, the restriction of the mounting method, and the like are solved. In addition, it is possible to indicate to the operator that the motor is approaching the overload limit value. Further, since the power consumption is calculated from the detected current and voltage values, the power consumption is not affected by the temperature change unlike the related art. Furthermore, since power consumption, electricity rates, etc. are calculated,
It can be a reference for data analysis.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 4 is a diagram for explaining a power supply system to a plurality of servomotors in the injection molding machine and prevention of overload of the servomotors.

[Explanation of symbols]

 11, 41 AC power supply 12, 42 Rectifier 13a to 13d, 43a to 43d Inverter 14a to 14d, 44a to 44d Servo motor 15 Magnetic contactor 16 First current detector 17, 21, 31 Controller 22 Load 23 Second current Detector 32 Power measurement device 45 Thermal relay

Claims (10)

[Claims] 1. An injection molding machine having a configuration in which power is supplied from an AC power supply via a rectifier to at least one inverter, and a motor is connected to the inverter as a load. An electromagnetic contactor is provided between the rectifier and the inverter, a first current detector is provided between the rectifier and the inverter, and an overload state of the motor is determined based on a detection value of the first current detector. An injection molding machine comprising a controller for determining. 2. The injection molding machine according to claim 1, wherein the controller determines the overload state of the motor and controls the electromagnetic contactor. 3. The injection molding machine according to claim 1, wherein the controller turns off the electromagnetic contactor when a detection value of the first current detector exceeds a preset limit value. Injection molding machine. 4. The injection molding machine according to claim 1, wherein the controller has a function of outputting a warning display when a detection value of the first current detector approaches a preset limit value. An injection molding machine characterized in that: 5. An injection molding machine having a configuration in which at least one inverter is supplied with power from an AC power supply via a rectifier, and a motor is connected to the inverter as a load. An electromagnetic contactor is provided between the rectifier and the inverter, and has a function of detecting a first voltage between the rectifier and the inverter, and a detection value of the first current detector and a detected first voltage value. Calculates the power consumption that has been integrated over an arbitrary period of time, the average power consumption per unit time or one molding cycle based on the calculated values, and displays these calculated values for numerical display, waveform display showing chronological changes, storage, and printing. An injection molding machine comprising a controller for controlling an output function or a communication function. 6. The injection molding machine according to claim 5, wherein the controller turns off the electromagnetic contactor when any one of the power consumption and the average power consumption exceeds a preset limit value. An injection molding machine characterized by the following. 7. The injection molding machine according to claim 5, wherein the controller displays a warning when any one of the power consumption and the average power consumption approaches a limit value set in advance for each. An injection molding machine having a function of performing output. 8. The injection molding machine according to claim 5, wherein another load is branch-connected between the AC power supply and the electromagnetic contactor, and a branch line to the another load is provided. Is connected to a second current detector, and the controller comprises:
A function of detecting a second voltage between the branch lines, wherein a value detected by the first current detector and a value detected by the first
The power amount or average power calculated from the voltage value and the power amount or average power calculated from the detected value of the second current detector and the detected second voltage value, or the total power consumption or An injection molding machine having a function of calculating an average power. 9. The injection molding machine according to claim 5, wherein another load is branch-connected between the AC power supply and the electromagnetic contactor, and a branch line to the another load is provided. Is connected to a power measuring device, and the controller measures a power amount or an average power calculated from a detected value of the first current detector and the detected first voltage value, and a measurement from the power measuring device. An injection molding machine having a function of calculating the total power consumption or the average power based on the values. 10. The injection molding machine according to claim 8, wherein the controller is configured to calculate an electric charge based on the power consumption accumulated over the arbitrary time or the power consumption accumulated over the arbitrary time and the total power consumption. An injection molding machine comprising: a controller for calculating and displaying the calculated value as a numerical value, displaying a waveform indicating a time series change, storing, outputting for printing, or a communication function.