JP3259919B2 - Rotating device with built-in power and signal transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission mechanism for transmitting electric power and signals to an electric load provided at an end of a rotating shaft such as a motor.

[0002]

2. Description of the Related Art In the field of machine tool machining, as shown in FIG. 10, the position of a tool post 104 is controlled by the tip of a spindle motor 101 (facer machining center), or machining is performed by the spindle end of a spindle motor 111 or a spindle unit 121. In some cases, such as chucking the object 114 (FIG. 11), it is desired to transmit power further on the rotating shaft and transmit and receive signals to perform work.

[0003]

In these cases, since power and signals could not be supplied easily in the past, as shown in FIG. 12, the spindle motor and the spindle unit 121 were made hollow and coaxial therewith. Shaft 123
However, it has been extremely difficult to put this into practical use at low cost due to problems in machining accuracy and long-term reliability.

In articulated robots and SCARA robots, power and signal transmission and reception for each electric output shaft are performed by a large number of wires, and the operation range of the robot arm is limited due to the problem of wiring. There was a problem such as fatigue fracture of wiring due to long-term repetitive operation.

[0005]

In order to solve the above-mentioned problems, the present invention according to claim 1 is directed to a primary type of split-type high-frequency transformer.
Between the fixed part and the rotating shaft, respectively.
The signal transmission coupler is located opposite to
One of the transmitter and receiver is on the fixed part side, the other is the rotating shaft
The secondary coil is disposed so as to have a gap on the
One of the transmitting unit and the receiving unit
A wiring which is provided in the groove or hollow hole on the rotating shaft of the rotating device, and which includes a mechanism for transmitting power and a signal to an electric load provided at an end of the rotating shaft. In the above, the rotating device is an electric motor,
A secondary coil is provided between the bearings of the rotary shaft supported at both ends by bearings so as to face the primary coil of the split-type high-frequency transformer, and to face the transmitter of the signal transmission coupler outside between the bearings. A receiving unit is provided. Further, according to the present invention, a primary coil and a secondary coil of a split type high-frequency transformer are provided.
The coil has a gap between the fixed part side and the rotating shaft side.
Opposed to transmit and receive signal transmission coupler
One of the parts has a gap on the fixed part side and the other has a gap on the rotating shaft side.
And the power supply of the secondary coil
Outgoing line, signal acquisition of one of the transmitting unit and the receiving unit
In a rotating device in which a wiring serving as a lead wire is provided in a groove or a hollow hole on the rotating shaft of the rotating device, and a mechanism for transmitting power and a signal to an electric load provided at an end of the rotating shaft is built in, The rotating device is a transmission, and both ends are supported by bearings.
A secondary coil is provided between bearings of a supported transmission output shaft so as to face a primary coil of the split-type high-frequency transformer, and a receiving unit is provided so as to face a transmitting unit of the signal transmission coupler. It is.

[0006]

A high-frequency transformer is used as power transmission means, and an electromagnetic induction or optical coupler is used as signal transmission means. The primary and secondary coils of the transformer are used, and the transmitting and receiving sides of the coupler are used. By separately providing the gaps on the rotating shaft side and the fixed portion side so as to face each other, power and signals can be transmitted without contact on the rotating shaft without wiring.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a principle configuration of contactless power transmission in the present invention. In the figure, a split-type high-frequency transformer Tr is configured such that a primary coil 11 disposed on a fixed side and a secondary coil 12 disposed on a rotating side are provided at a slight interval. The primary coil 11 is connected to a high-frequency voltage generator serving as a power supply for supplying power to the secondary coil 12, and the secondary coil 12 is connected to a load or the like.

FIG. 2 is a diagram showing a specific configuration of the split type high-frequency transformer according to the present invention.
Type and the case of type B which is a rotary machine type. In the case of a pot type core (type A), the pot core 20 around which the primary winding 21 is wound and the pot core 20 around which the secondary winding 22 is wound are abutted at intervals to perform electromagnetic induction. Since this type has a flat shape in structure, it has little effect on the shape increase in the direction of the rotating shaft when it is housed in an electric motor or a reduction gear. Since the direction is the direction, the amount of magnetic flux passing therethrough tends to be limited from the upper limit of the magnetic flux density of the core material. On the other hand, type B is similar to the relationship between the rotor and the stator of the rotating machine,
This is a concentric type in which another core is inserted inside the cylindrical core, and the magnetic path is perpendicular to the rotation axis direction as shown in the figure. However, there is an advantage that the amount of magnetic flux passing per unit volume can be increased as in a normal electric motor, and a high overall power rate (transmission power per unit volume) can be obtained. However, in the case of the type B, it is necessary to apply a skew in electrical angle to one of the cores as shown in the figure so that the magnetic path length (or magnetic resistance) does not change depending on the rotation angle. In the figure, the core inserted inside is skewed.

In any case, as shown in FIG. 1, the primary side (fixed side) of the split-type high-frequency transformer Tr is excited by a high-frequency (sinusoidal or rectangular) inverter, and is opposed to the secondary side with a small gap. A high-frequency voltage is generated on the side (rotating part) by electromagnetic induction. Here, the split type high-frequency transformer Tr
The gap between the primary and secondary magnetic cores is made as small as possible to reduce the loss due to the air gap.

Even if the primary and secondary cores rotate relative to each other on the same axis, as long as the equivalent electric frequency of the rotation is lower than the above-mentioned high frequency excitation frequency, there is substantially no disturbance in the magnetic field distribution. There is no change in the power transmission characteristics at both the time and the stop. Next, contactless signal transmission in the present invention will be described. FIG. 3 shows an example using electromagnetic induction, and FIG. 4 shows an example using an optical coupler. FIG. 3-A has the same structure as the type A of FIG.
In FIG. 3B, a transmission side on which the transmission winding 21 is wound and a reception side on which the reception winding 22 is wound are abutted to each other with a slight gap therebetween (FIG. 3-B). FIG. 4A is a diagram for optically transmitting information from a rotating unit to a fixed unit, and includes a plurality of light emitting element groups 41 arranged in series in a ring on a rotating disk 40 attached to a rotating shaft; It is arranged on a fixed portion surrounding the disk, and includes one light receiving element 42 for receiving light from the light emitting element group 41.
FIG. 4B is a diagram for optically transmitting information from the fixed portion to the rotating portion, and includes a plurality of light emitting element groups 41 arranged annularly in the fixed portion and a rotating disk 40 attached to a rotating shaft. And one light receiving element 42 for receiving light from the light emitting element group 41. The wiring of these rotating parts is performed via the rotating shaft hollow part 43. In any case, even if the transmitter and the receiver are rotating at a relatively high speed without any contact, signal transmission can be performed reliably.

FIG. 5 shows a configuration of an embodiment of the present invention, in which a power transmission unit and a signal transmission unit are incorporated in a main shaft motor (or a general motor). In the figure, a primary core 51 of a high-frequency electromagnetic induction core disposed on a fixed side close to a bearing is provided inside a housing of an electric motor composed of a stator 53 and a rotor 54.
And a secondary core 52 provided on the rotating shaft 50 through a gap opposed thereto, and the primary and secondary cores form the above-mentioned split type high-frequency transformer. Primary side core 5
Similarly to the stator 53 of the torque (power) transmission unit, the winding No. 1 is excited through a power line, and the winding output of the secondary side core is a power extraction line wired through a groove or a hollow hole on the rotating shaft 50. Through 59, it is taken out to the tip of the rotating shaft (see FIG. 13). With respect to the power transmission unit and the power transmission unit (collectively, the power transmission unit), an information transmission unit is disposed on the non-load side via a bearing. Numerals 55 and 56 respectively form optical or high-frequency electromagnetic induction couplers for signal transmission. One is provided on the fixed side and the other is provided on the rotating shaft side, and can be either a transmitting unit or a receiving unit as necessary. . Signal exchange with an electric load provided at the shaft end is performed via a signal extraction line 58 wired through a groove or a hollow hole on the rotating shaft (see FIG. 13). In FIG. 5, a plurality of pairs of signal couplers 55 and 56 are provided. In this case, each pair is not affected by leakage of an optical signal and an electromagnetic induction signal from another pair. Need to be shielded. In particular, when a plurality of optical couplers are used and the peak wavelengths of the response spectra of the individual couplers are significantly different from each other, the above-described shielding is not required. Also, a conventional motor sensor (for example, a position detection encoder) 5 built in the motor.
The power supply 7 can be shared as a drive power supply for the above-described signal coupler, and further, signal processing such as waveform shaping of the coupler output can be collectively performed by the signal processing unit of the conventional sensor.

FIGS. 6 and 7 show an example in which the power transmission unit and the signal transmission unit are incorporated in the reduction gear casing based on the same idea, and the input shaft and the output shaft are not coaxial (FIG. 6). And the case where the input shafts are coaxially arranged (FIG. 7). Referring to FIG. The rotation of the electric motor 67 is transmitted to the output shaft 62 at a reduced speed via the gear train 61 in the housing. The output shaft 62 is supported at both ends by bearings on both sides of the reduction gear housing. Between the output shaft 62, the secondary core 64 of the split type high-frequency transformer and the receiving section 66 of the signal coupler are mounted. 68 and 69 are wired in grooves or hollow holes on the output shaft 62 and are led out to an electric load provided at the tip of the output shaft. Also, on the inside of the housing,
The primary core 63 of the split-type high-frequency transformer and the transmitting section 65 of the signal coupler are mounted to face the secondary core 64 and the receiving section 66 on the output shaft side with a gap therebetween.
FIG. 7 differs from FIG. 6 only in that the input and output shafts are coaxially arranged and that a harmonic gear (precession gear) is used as the speed change step. The operation is the same as in the case where the motor is incorporated into the motor. A power transmission unit and a signal transmission unit are mounted on the output shaft, and these wirings 58 and 59 are provided at the end through grooves or hollow holes on the output rotation shaft. Taken out of the electrical load. The order of the on-axis positions of the power transmission unit and the signal transmission unit may be interchanged.

An electric motor or a reduction gear unit having the same effect as described above, which can transmit electric power and signals to the output shaft end, uses an electric load such as a motor at these rotary output shaft ends. The method of transmitting power signals to the power supply and driving them is as follows. In the case of an electrical load that generates light or temperature, the load is an effective value load, and the high-frequency voltage extracted from the shaft end may be supplied to the load as it is. Also, when driving the high frequency motor, the shaft end take-out voltage may be applied as it is. However, in the case of a general motor load, DC or
In order to operate in a lower frequency region, it is necessary to insert a high frequency rectifier circuit 83 (comprising a diode and an LC filter) at the end of the shaft end as shown in FIG. Then, from this DC voltage, (1)
(2) controlling a load 86 through a power switch element bridge 85 such as a transistor.

Thus, the DC motor, the synchronous motor,
Although all of the induction motors are controlled before the end of the rotary shaft, it is not particularly necessary to mount all the conventional motor controllers at the end of the shaft. This is because the signal transmission (for input and output) is performed from the fixed side of the motor, speed reducer, etc. to the output shaft end by non-contact transmission as described above. For example, the signal is mounted on the motor mounted before the shaft end. If the position information and speed information obtained by the detected detector are returned to the fixed side by this transmission channel and the torque command information is given from the fixed side to the shaft end side by another signal transmission channel, the position and speed of the motor control Control can be performed on the fixed side, and torque control can be performed before the shaft end. In this way, it is also possible to adopt a method of reducing the weight and physical size of the control unit attached before the shaft end.

The power of the control unit and the detector before the shaft end is supplied after being stabilized from the rectified transmission power through the automatic voltage regulator (AVR) 93 in the form of FIG. The above description focuses on the case where an electric load is taken before the shaft end and work is performed using transmission power. However, a small amount of power is applied before the shaft end (or power may be supplied in some cases). The invention is also useful in limited applications where the detector is operated (even without it) and this signal is transmitted to the fixed side. In this case, the above-described power transmission unit can be extremely small (or eliminated).

In FIG. 5, FIG. 6 and FIG. 7, the high-frequency induction power transmission is performed in a single phase. However, this is performed by (1) increasing the transmission power, and (2) directly using a high-frequency motor or a stepping motor. For control, (3) to reduce the load on the rectifier circuit, it is also effective to increase the number of phases for one or more reasons. The power and signal transmission elements as described above are integrated into a motor or a speed reducer, and (1) the rotation of the output shaft (particularly heavy power transmission) is interposed between the bearings to suppress the output shaft rotation runout. (2) It facilitates the management of the gap in the contactless power transmission section and the management of the atmosphere in the gap (prevention of the inclusion of dust and the like). (3) Especially, the signal transmission section using the optical coupler is the same as the conventional optical encoder (4) When incorporating into a motor, the torque generation section of the conventional motor and the above-described power transmission section are collectively integrated as a power transmission section, and the sensor section such as the optical encoder of the conventional motor and A rational configuration can be realized by collectively managing the atmosphere of the signal transmission units.

The embodiment of the present invention is not limited to the precise motor control application field such as the above-described joints of the robot arm and the machine tool (particularly, the driving of the tip of the spindle), as well as power supply and information exchange via rotating parts. In every field that needs
This includes all applications that have traditionally caused problems such as fatigue and wear using wired systems or slip rings.

[0018]

According to the present invention, power transmission and signal transmission via a rotating part, which could not be performed conventionally, can be performed, and a non-contact transmission part for that purpose is incorporated in a motor or a speed reducer (particularly when the motor is built in the motor). ) Stabilizes the mechanism of the rotating unit by treating the conventional power transmission unit and power transmission unit collectively as a power transmission unit and treating the sensor unit and signal transmission unit collectively as an information transmission unit. At the same time, the transmission section is insulated from the external environment and the gap and atmosphere can be managed.

Wiring for power transmission and information transmission through the groove or the hole of the output shaft can be performed without affecting the power transmission, and the shielding effect of the output shaft grounded via the bearing is achieved. Can be expected, and the effects of noise emitted to the outside and noise received from the outside can be drastically reduced. Further, according to the present invention, since the detector information can be obtained from the shaft end via the rotating part, the conventional mechanical power transmission (for example, FIG.
It can also be used in combination with 2) for its control.

According to the above effects, if a plurality of electric motors or reduction gears having a built-in power and signal transmission mechanism configured as in the present invention are used in combination, there is no wiring and each axis can be easily attached and detached and replaced. Machine (machine tool, robot) can be configured.

[Brief description of the drawings]

FIG. 1 is a diagram showing the principle of contactless power transmission in the present invention.

FIG. 2 is a diagram showing a configuration of a split-type high-frequency transformer for transmitting electric power in a contactless manner in the present invention.

FIG. 3 is a diagram showing a configuration of an electromagnetic induction type for transmitting signals without contact in the present invention.

FIG. 4 is a diagram showing a configuration of an optical coupler for transmitting a signal without contact according to the present invention.

FIG. 5 is a diagram showing a configuration of one embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of another embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of another embodiment of the present invention.

FIG. 8 is an electric circuit diagram when the embodiment of the present invention is applied.

FIG. 9 is an electric circuit diagram when an embodiment of the present invention is applied.

FIG. 10 is a view showing the state of tool post positioning at the tip of the spindle motor.

FIG. 11 is a diagram showing a state of work chucking at a spindle motor shaft end.

FIG. 12 is a diagram showing a mechanical power transmission mechanism using a coaxial shaft.

FIG. 13 is a sectional view showing a state of a groove on a rotating shaft and wiring in a hollow hole.

[Explanation of symbols]

Tr Divided high-frequency transformer 10 High-frequency voltage generator 11, 51, 63, 73, 81 Primary 12, 52, 64, 74, 82 Secondary 20 High-frequency magnetic core 21, 22 Winding 30 High-frequency magnetic core 31 Transmitting side 32 Receiving side 41 Issuing element group 42 Light receiving element 55, 56: 65, 66: 75, 76 Signal transmission coupler 58, 68, 78 Signal extraction line 59, 69, 79 Power extraction line

Claims (2)

(57) [Claims] 1. A primary coil and a secondary coil of a split-type high-frequency transformer
The coil has a gap between the fixed part side and the rotating shaft side.
Opposed to transmit and receive signal transmission coupler
One of the parts has a gap on the fixed part side and the other has a gap on the rotating shaft side.
And the power supply of the secondary coil
Outgoing line, signal acquisition of one of the transmitting unit and the receiving unit
In a rotating device in which a wiring serving as a lead wire is provided in a groove or a hollow hole on the rotating shaft of the rotating device, and a mechanism for transmitting power and a signal to an electric load provided at an end of the rotating shaft is built in, The rotating device is an electric motor, and a secondary coil is provided between bearings of a rotating shaft supported at both ends by bearings so as to face a primary coil of the split high-frequency transformer, and the signal transmission is provided outside between the bearings. A rotating device having a built-in power and signal transmission mechanism, wherein a receiving unit is provided to face a transmitting unit of the coupler. 2. A primary coil and a secondary coil of a split type high frequency transformer.
The coil has a gap between the fixed part side and the rotating shaft side.
Opposed to transmit and receive signal transmission coupler
One of the parts has a gap on the fixed part side and the other has a gap on the rotating shaft side.
And the power supply of the secondary coil
Outgoing line, signal acquisition of one of the transmitting unit and the receiving unit
In a rotating device in which a wiring serving as a lead wire is provided in a groove or a hollow hole on the rotating shaft of the rotating device, and a mechanism for transmitting power and a signal to an electric load provided at an end of the rotating shaft is built in, The rotating device is a transmission, and a secondary coil is provided between bearings of a transmission output shaft supported at both ends by bearings so as to face a primary coil of the split-type high-frequency transformer. A rotating device having a built-in power and signal transmission mechanism, characterized in that a receiving unit is provided to face the transmitting unit.