Magnetic modulation gear device, drive device and robot

Abstract

To eliminate the need for a torque sensor.SOLUTION: A magnetic modulation gear device 30 includes an input shaft 23, an output shaft 32b that is shifted and output with respect to the input shaft 23 through a reduction gear unit, an input shaft-side sensor 35 that measures a rotation angle on the input shaft 23 side, and an output shaft-side sensor 36 that measures a rotation angle on the output shaft 32b side. For example, a drive device 1 includes the magnetic modulation gear device 30, a drive source 20 that inputs torque to the input shaft, and a control device 40 that controls the amount of operation of the drive source to achieve a target torque on the basis of the measured rotation angle of the input shaft side and the measured rotation angle of the output shaft side. The drive device 1 controls the torque on the output shaft side without using a torque sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a magnetic modulation gear device, a drive device, and a robot. [Background technology]

[0002] Conventionally, a magnetic modulation gear device has been known in which a pole piece member having multiple pole pieces is placed between two magnets arranged on the inner and outer periphery, and the magnetic flux distribution between the inner and outer periphery is modulated. This magnetic modulation gear device transmits torque between the inner periphery magnet and its pole piece member, thereby transmitting reduced or increased speed rotation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-17984 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional magnetic modulation gear devices have been required to control the torque transmitted.

[0005] The present invention has been made in view of the above circumstances, and has an object to enable suitable torque control. [Means for solving the problem]

[0006] The present invention provides a magnetic modulation gear device, A magnetic modulation gear device having an input shaft and an output shaft whose speed is changed relative to that of the input shaft through a reduction section of a magnetic modulation gear, The rotation angle of the input shaft degree an input shaft side sensor for measuring; Rotation angle of the output shaft degree The output shaft side sensor to be measured Equipped with a housing, At least the input shaft side sensor or the output shaft side sensor is provided in the internal space of the housing, The rotation angle measured by the input shaft side sensor and the output shaft side sensor every time The torque control is configured to adjust the torque input to the input shaft based on the torque control signal, thereby controlling the torque of the output shaft.

[0007] The present invention also provides a drive device, The magnetic modulation gear device; a drive source that inputs torque to the input shaft; a control device that controls the torque of the drive source based on a difference between a target torque and a torque estimated by a torque estimation unit that estimates a torque transmitted from the input shaft to the output shaft based on a rotation angle measured by an input shaft side sensor and a rotation angle measured by the output shaft side sensor; The configuration is provided with the following.

[0008] The present invention also provides a drive device, The magnetic modulation gear device; a drive source that inputs torque to the input shaft; a control device that controls the amount of operation of the drive source so as to achieve a target torque based on the measured rotation angle of the input shaft side and the measured rotation angle of the output shaft side; The configuration is provided with the following.

[0009] Furthermore, the present invention provides a robot having the above-described drive device. [Effects of the Invention]

[0010] According to the present invention, torque control can be performed without providing a dedicated torque sensor. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is an axial cross-sectional view of the drive device according to the first embodiment. [Figure 2] FIG. 2 is a perspective view of a magnetic modulation gear device. [Figure 3]FIG. 4 is a diagram showing the relationship between the phase difference and the output torque in the output shaft. [Figure 4] FIG. 10 is an axial cross-sectional view of a drive device according to a second embodiment. [Figure 5] FIG. 10 is an axial cross-sectional view of a drive device according to a third embodiment. [Figure 6] FIG. 1 is a side view of a robot to which the drive device is applied. DETAILED DESCRIPTION OF THE INVENTION

[0012] [First embodiment] A first embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an axial cross-sectional view of a drive device 1 according to a first embodiment. As shown in this figure, the drive device 1 according to this embodiment includes a motor 20, a magnetic modulation gear device 30, and a control device 40 that controls the torque of the drive device 1.

[0013] [Motor] The motor 20 is exemplified by a motor whose rotation angle can be controlled, such as a brushless motor. The motor 20 includes a motor rotor and a motor stator (both not shown), and the motor rotor includes a shaft 23, a rotor yoke 31b, and an internal magnet (rotor magnet) 31a. The rotor yoke 31b is made of a magnetic material and is provided on the outer circumferential surface of the shaft 23, and the internal magnet 31a is provided on the outer circumferential surface of the rotor yoke 31b. The motor stator is made up of a stator core around which a plurality of coils are wound, and the motor rotor (shaft 23) is rotated by exciting the plurality of coils in a predetermined order. The shaft 23 also extends into the magnetic modulation gear device 30 . In the following description, the direction along the central axis Ax of the shaft 23 is referred to as the "axial direction," the direction perpendicular to the central axis Ax as the "radial direction," and the rotation direction around the central axis Ax as the "circumferential direction." In addition, within the axial direction, the side where the output shaft 32b of the driving device 1 is connected to an external driven member (left side in the drawing) is referred to as the "load side," and the side opposite the load side (right side in the drawing) is referred to as the "anti-load side."

[0014] [Magnetic modulation gear device] The magnetic modulation gear device 30 is disposed on the load side of the motor 20 and functions as a transmission (e.g., a reducer) that changes the speed of the rotation input from the motor 20 and outputs it to the load side. The magnetic modulation gear device 30 and the motor 20 share the shaft 23. In other words, the shaft 23 functions as the input shaft of the magnetic modulation gear device 30. Specifically, the magnetic modulation gear device 30 includes a high-speed rotor 31, a low-speed rotor 32, an outer pole magnet 33, a casing 34 as a housing, a high-speed shaft rotation angle sensor 35 as an input shaft side sensor that measures the rotation angle on the shaft 23 side, a low-speed shaft rotation angle sensor 36 as an output shaft side sensor that measures the rotation angle on the output shaft 32b side, and a temperature sensor 37 that detects the temperature of the magnet of the magnetic modulation gear device 30.

[0015] As shown in Figure 1, the casing 34 is a cylindrical body concentric with the shaft 23, and the shaft 23 of the motor 20 passes through the center of the casing 34 and reaches from the anti-load side cover 11 that closes the anti-load side end of the casing 34 to the inside of the hollow output shaft 32b provided in the load side cover 13 that closes the load side end of the casing 34. The shaft 23 is supported by a bearing 12a (for example, a ball bearing) provided at the center of the counter-load side cover 11 and a bearing 12b (for example, a ball bearing) provided on the inner periphery of the output shaft 32b. It is supported rotatably around an axis Ax.

[0016] The output shaft 32b is disposed concentrically with the shaft 23 on the load side of the shaft 23. The output shaft 32b has a solid shaft portion 321b, a hollow cylindrical portion 322b provided at the end of the shaft portion 321b on the anti-load side, and a flange portion 323b provided on the outer periphery of the end of the cylindrical portion 322b on the anti-load side. The shaft portion 321b, the cylindrical portion 322b, and the flange portion 323b of the output shaft 32b are integrated and disposed concentrically with the shaft 23. The outer periphery of the cylindrical portion 322b is rotatably supported by a bearing 32f (e.g., a ball bearing) provided in the center of the load-side cover 13. Furthermore, the anti-load side end of the cylindrical portion 322b opens toward the anti-load side, and rotatably supports the shaft 23 by a bearing 12b on the inner periphery. Note that the output shaft 32b does not have to be hollow as long as the load side end of the shaft 23 is not supported inside the output shaft 32b. Alternatively, the load side (not shown) of the output shaft 32b may be a solid shaft. In other words, the shape of the output shaft is not particularly limited.

[0017] FIG. 2 is a perspective view of the magnetic modulation gear device 30. 1 and 2, the high-speed rotor 31 includes a shaft 23, a rotor yoke 31b, and an internal magnet 31a. The rotor yoke 31b is fixedly attached to the outer periphery of the shaft 23 at a position within the casing 34 that is approximately midway in the axial direction (strictly speaking, somewhat toward the anti-load side). The rotor yoke 31b has a uniform outer diameter over its entire axial length, and the internal magnet 31a is fixedly attached to its outer periphery. The internal magnet 31a also has a uniform outer diameter over its entire axial length.

[0018] The inner pole magnets 31a are permanent magnets such as neodymium magnets, and multiple magnets with opposite polarities are attached alternately along the circumferential direction to the outer circumferential surface of the rotor yoke 31b. These inner pole magnets 31a form magnetic poles consisting of multiple pole pairs. Alternatively, multiple inner pole magnets 31a may be configured as a single ring-shaped magnet.

[0019] The low-speed rotor 32 has the above-mentioned output shaft 32b and a plurality of magnetic pole pieces 32a. The plurality of magnetic pole pieces 32 a are arranged concentrically with the high-speed rotor 31 and surrounding the periphery of the high-speed rotor 31 . The multiple pole pieces 32a are formed from laminated steel plates and are arranged at predetermined intervals in the circumferential direction. The pole pieces 32a may be made of any soft magnetic material. For example, they may be powder magnetic cores, amorphous, SPCC, etc. The number of pole pieces 32a is the number of outer pole pairs (the number of pole pairs of the outer pole magnets 33) ± the number of inner pole pairs (the number of pole pairs of the inner pole magnets 31a), and is generally the number of outer pole pairs + the number of inner pole pairs. Two circumferentially adjacent pole pieces 32a may be connected by a thin connecting portion or a non-magnetic material.

[0020] Resin portions 32c are fixed to both axial ends of the pole piece 32a, and a flange portion 323b of the output shaft 32b is fixed to the load-side resin portion 32c with bolts 32d (made of resin, for example, super engineering plastic). Note that the connection method is not limited to connection with bolts 32d. For example, the resin portion 32c and the output shaft 32b may be integrally molded. As described above, the load-side shaft portion 321b of the output shaft 32b is exposed from the casing 34 and is connected to a driven member (not shown). The low-speed rotor 32 is rotatably supported by the casing 34 via a bearing 32e provided on the anti-load side of the pole piece 32a and a bearing 32f supporting the output shaft 32b. Of these, the anti-load side bearing 32e is disposed between the casing 34 and a stainless steel ring member 32g fixed to the anti-load side resin portion 32c of the pole piece 32a. As described above, the load side bearing 32f is disposed between the load side cover 13 of the casing 34 and the cylindrical portion 32 of the output shaft 32b. It is located between 2b.

[0021] The outer magnets 33 are arranged concentrically around the outer peripheries of the multiple pole pieces 32a with a predetermined gap between them. These outer magnets 33 have a greater number of pole pairs than the inner magnets 31a of the high-speed rotor 31, and multiple magnets with opposite polarities are arranged alternately in the circumferential direction. These outer magnets 33 are attached in the above-mentioned arrangement to the inner circumferential surface of a yoke portion 33a fitted inside the casing 34, and function as a stator. Alternatively, multiple outer magnets 33 may be configured as an integrated ring-shaped magnet. The inner magnet 31a, the magnetic pole piece 32a, and the outer magnet 33 described above constitute a speed reducer portion provided between the input shaft and the output shaft.

[0022] The high speed shaft rotation angle sensor 35 has a detection target 351 that rotates integrally with the shaft 23 , and a sensor unit 352 that is disposed near the detection target 351 and detects the detection target 351 . The slow speed shaft rotation angle sensor 36 has a detected part 361 that rotates integrally with the output shaft 32b, and a sensor part 362 that is arranged near the detected part 361 and detects the detected part 361. The high speed shaft rotation angle sensor 35 and the low speed shaft rotation angle sensor 36 are arranged in the same space inside the casing 34.

[0023] The high speed shaft rotation angle sensor 35 and the low speed shaft rotation angle sensor 36 are exemplified by rotary encoders that output the rotational displacement of the shaft 23 and the output shaft 32b as digital signals, but they may also be resolvers that output the displacement as analog signals, or other rotation detectors. The rotary encoder may have an optical detection unit or a magnetic detection unit. Furthermore, the high speed shaft rotation angle sensor 35 and the low speed shaft rotation angle sensor 36 may be different types of detectors.

[0024] The detected part 351 of the high-speed shaft rotation angle sensor 35 is composed of a disk (or ring) fixed to the shaft 23 at a position facing the load-side surface of the anti-load-side cover 11. The detected part 351 is mounted concentrically with the shaft 23 and rotates together with the shaft 23 around the central axis Ax. For example, a code that can be optically or magnetically read from the anti-load side is formed along the circumference of a circle centered on the central axis Ax on the anti-load side surface of the detected part 351. Furthermore, when the detected part 351 is formed in a ring shape, these codes may be formed on the outer or inner circumference of the ring.

[0025] The sensor unit 352 is fixedly mounted on the load side surface of the anti-load side cover 11 of the casing 34. The sensor unit 352 is disposed so as to closely face the detected part 351. The sensor unit 352 is configured, for example, by an optical sensor or a magnetic sensor capable of reading the code on the detected part 351.

[0026] The detected portion 361 of the low-speed shaft rotation angle sensor 36 is composed of a disk (or ring) fixedly mounted on the outer periphery of the flange portion 323b of the output shaft 32b. The detected portion 361 is mounted concentrically with the output shaft 32b and rotates around the central axis Ax together with the output shaft 32b. For example, an optically or magnetically readable code is formed along the circumference of a circle centered on the central axis Ax on the load side surface of the detected portion 361. Furthermore, when the detected portion 361 is formed in a ring shape, the code may be formed on the outer or inner circumference of the ring.

[0027] The sensor unit 362 is fixedly mounted on the inner periphery of the casing 34 near the load side of the flange portion 323b of the output shaft 32b. The sensor unit 362 is disposed to extend radially inward so as to closely face the detected portion 361. The sensor unit 362 is configured, for example, by an optical sensor or a magnetic sensor capable of reading the code on the detected portion 361.

[0028] In the above example, the detection target portions 351, 361 and the sensor portions 352, 362 of the high-speed shaft rotation angle sensor 35 and the low-speed shaft rotation angle sensor 36 are arranged to face each other in the axial direction, but the relative positions of the sensor portions and non-detection portions are not particularly limited. For example, if the codes of the detection target portions 351, 361 are formed on the outer or inner circumference of the ring, the sensor portions 352, 362 may be arranged radially outside or inside the detection target portions 351, 361, so that the detection target portions 351, 361 and the sensor portions 352, 362 face each other in the radial direction.

[0029] The temperature sensor 37 detects the temperature of the external magnet 33, which serves as a magnet. This temperature sensor 37 is attached to the external magnet 33. As the temperature sensor 37, a sensor that can detect the temperature by contacting the object to be measured, such as a thermocouple, a resistance thermometer, or a thermistor, can be used, but is not limited to these as long as it can measure the temperature of the object to be measured. For example, a non-contact sensor that can detect the temperature from a position separated from the object to be measured, such as an infrared detector, may also be used.

[0030] [Control device] When the motor 20 of the drive device 1 is driven, an input torque is applied to the shaft 23. This causes the high-speed rotor 31 of the magnetic modulation gear device 30 to rotate together with the shaft 23, and the spatial magnetic flux waveform of the internal pole magnet 31a of the high-speed rotor 31 is frequency-modulated by the magnetic pole piece 32a of the low-speed rotor 32, transmitting torque to the low-speed rotor 32. At this time, the reduction ratio is (number of magnetic poles of the magnetic pole piece 32a of the low-speed rotor 32) / (number of pole pairs of the internal pole magnet 31a).

[0031] FIG. 3 is a diagram showing the relationship between the phase difference and the output torque in the output shaft 32b. As described above, in the magnetic modulation gear device 30, the pole pieces 32a and the output shaft 32b rotate at a reduction ratio determined by (the number of magnetic poles in the pole pieces 32a of the low-speed rotor 32) / (the number of pole pairs of the internal pole magnet 31a) relative to the rotation angle of the shaft 23. If the rotation angle of the output shaft 32b when the output shaft 32b rotates at a rotation angle corresponding to the reduction ratio relative to the rotation of the shaft 23 is taken as a reference position, when a phase difference occurs due to a delay in the rotation angle of the output shaft 32b relative to the reference position of the output shaft 32b, an output torque is generated on the output shaft 32b. The output torque generated on the output shaft 32b has a correlation with the phase difference, for example, as shown in FIG. 3. In the example of Figure 3, the period of one magnetic pole piece 32a is 360 degrees, and when the phase difference generated in the output shaft 32b is 0 or ±180 degrees, the output torque of the output shaft 32b is 0, and when the phase difference is ±90 degrees, the output torque is at its maximum.

[0032] The control device 40 executes torque control based on the characteristics of the phase difference generated in the output shaft 32b and the output torque of the output shaft 32b. Specifically, as shown in FIG. 1, the control device 40 generates a torque command T * , the target phase difference θ of the output shaft 32b for outputting the target output torque * a phase difference output unit 41 that outputs the phase difference θ_fb currently occurring in the output shaft 32b; and a phase difference calculation unit 42 that calculates the target phase difference θ * and a subtractor 43 for calculating a deviation θ_cmd between the phase difference θ_fb currently occurring in the output shaft 32b. The above-described components of the control device 40 may be realized by hardware, or the control device 40 may be configured as an arithmetic processing device and may be functionally realized by software processing.

[0033] The phase difference output unit 41 stores table data based on the characteristics (for example, the characteristics shown in FIG. 3) between the phase difference generated in the output shaft 32b of the low-speed rotor 32 and the output torque generated in the output shaft 32b. The table data is used to calculate the torque command T *Target phase difference θ of the output shaft 32b corresponding to each of a plurality of values ​​of (target output torque) * The value of the phase difference output unit 41 is determined as the torque command T * When the target phase difference θ of the corresponding output shaft 32b defined in the table data is input, * Identify and output.

[0034] In addition, different table data are prepared for each of a plurality of rotation angles of the shaft 23. Furthermore, the table data for each rotation angle of the shaft 23 is set to the target phase difference θ * Table data with corrected values ​​is prepared for a number of different temperatures. Therefore, the phase difference output unit 41 selects appropriate table data based on the rotation angle of the shaft 23 detected by the sensor unit 352 of the high speed shaft rotation angle sensor 35 and the temperature detected by the temperature sensor 37, and then calculates the target phase difference θ * Identify and output.

[0035] The phase difference calculation unit 42 receives as input the rotation angle of the shaft 23 detected by the sensor unit 352 of the high speed shaft rotation angle sensor 35 and the rotation angle of the output shaft 32b detected by the sensor unit 362 of the low speed shaft rotation angle sensor 36. The phase difference calculation unit 42 determines, from the detected rotation angle (phase) of the shaft 23, the rotation angle (phase) of the output shaft 32b when the output shaft 32b is rotating at a rotation angle according to the reduction ratio set for the magnetic modulation gear device 30, as a reference position. Furthermore, it determines the difference between the reference position and the rotation angle (phase) of the output shaft 32b detected by the low-speed shaft rotation angle sensor 36, and calculates the phase difference θ_fb occurring in the output shaft 32b.

[0036] The subtractor 43 subtracts the torque command T * Target phase difference θ of the output shaft 32b to obtain the target output torque *The phase difference θ_fb actually occurring in the output shaft 32b output from the phase difference calculation unit 42 is subtracted from the phase difference θ_cmd to calculate the deviation θ_cmd of the phase difference of the output shaft 32b. Furthermore, the phase difference deviation θ_cmd is multiplied by a predetermined gain, and the multiplied value is input as the operation amount of the motor 20. As a result, the target phase difference θ * The amount of motion input from the motor 20 to the shaft 23 is controlled so that the torque command T * A target output torque corresponding to the target output torque is generated.

[0037] [Technical effect of the first embodiment] The magnetic modulation gear device 30 of the drive device 1 has a high-speed shaft rotation angle sensor 35 that measures the rotation angle of the shaft 23 side and a low-speed shaft rotation angle sensor 36 that measures the rotation angle of the output shaft 32b side. Therefore, the phase difference occurring in the output shaft 32b can be easily obtained from the outputs of these sensors 35, 36. Furthermore, it is possible to easily correspond to the torque control of the output torque on the output shaft 32b side based on the phase difference, thereby performing suitable torque control. This allows the drive unit 1 to easily control the output torque without providing a dedicated torque sensor for torque detection, which simplifies the device configuration, reduces the number of parts, and thereby makes it possible to downsize the device and reduce manufacturing costs.

[0038] Furthermore, the drive unit 1 has a high-speed shaft rotation angle sensor 35 and a low-speed shaft rotation angle sensor 36 disposed inside a casing 34 of the magnetic modulation gear device 30. Unlike reduction gears that utilize gear meshing, the magnetic modulation gear device 30 does not require lubricating oil inside the casing 34, so the sensors 35, 36 can be disposed in a clean environment. Furthermore, the casing 34 protects the sensors 35, 36 from external contact, impact, and adhesion of dust, etc., so the sensors 35, 36 can perform stable detection over a long period of time, thereby improving the reliability of the device.

[0039] Further, the driving device 1 outputs a torque command T from the output shaft 32b based on the rotation angle of the shaft 23 detected by the sensor unit 352 of the high speed shaft rotation angle sensor 35 and the rotation angle of the output shaft 32b detected by the sensor unit 362 of the low speed shaft rotation angle sensor 36. * It was established Since the control device 40 is provided to control the amount of operation of the motor 20 so that the target output torque is output, a torque sensor is not required, and torque control of the drive device 1 can be achieved with a simple configuration.

[0040] In addition, the control device 40 corrects the operating amount of the motor 20 that corresponds to the target output torque based on the temperature of the outer pole magnet 33 of the magnetic modulation gear device 30 detected by the temperature sensor 37, so that the drive device 1 can perform more accurate torque control by reflecting the influence of temperature.

[0041] [Second embodiment] A second embodiment of the present invention will be described with reference to the drawings. Figure 4 is an axial cross-sectional view of a drive device 1A according to the second embodiment. The driving device 1A of the second embodiment will be described mainly in terms of the differences from the driving device 1. As shown in Fig. 4, the driving device 1A differs from the driving device 1 mainly in that the motor 20A and the magnetic modulation gear device 30 share a casing 34A.

[0042] As shown in FIG. 4, the casing 34A houses the internal configuration of the motor 20A and the internal configuration of the magnetic modulation gear device 30, and is therefore formed of a cylindrical body that is longer in the axial direction than the casing 34 described above. The anti-load side end and load side end of the casing 34 are provided with an anti-load side cover 11 and a load side cover 13, respectively, and at the center of these, the shaft 23 common to the motor 20A and the magnetic modulation gear device 30 is rotatably supported around the central axis Ax by bearings 12a and 12b, and the output shaft 32b is rotatably supported around the central axis Ax by bearing 32f, just like the drive unit 1.

[0043] Furthermore, the motor 20A includes a motor rotor 21 and a motor stator 22. The motor rotor 21 has a shaft 23, a rotor yoke 21b, and a rotor magnet 21c. The rotor yoke 21b is made of a non-magnetic material and is fitted and fixed to the outer peripheral surface of the shaft 23. The rotor magnet 21c is a permanent magnet such as a neodymium magnet, and a plurality of rotor magnets 21c corresponding to a predetermined number of pole pairs are attached to a portion of the outer peripheral surface of the rotor yoke 21b that is located on the inner diameter side of the motor stator 22. The motor stator 22 is configured by winding a coil 22b around a stator core 22a made of laminated steel plates. The stator core 22a may also be made of any soft magnetic material, such as a powder magnetic core, amorphous, SPCC, etc. The motor stator 22 is concentrically disposed on the outer diameter side of the motor rotor 21, and is held by the casing 34A with the stator core 22a fitted inside the casing 34A.

[0044] On the other hand, the magnetic modulation gear device 30 differs in that the high-speed rotor 31A uses the rotor yoke 21b common to the motor 20A instead of the rotor yoke 31b described above. In other words, the rotor yoke 21b provided on the outer periphery of the shaft 23 extends to the inside of the magnetic modulation gear device 30 provided on the load side of the motor 20A, and multiple internal pole magnets 31a are attached to the outer periphery of the load side end of the rotor yoke 21b to form the high-speed rotor 31A of the magnetic modulation gear device 30.

[0045] The slow-speed shaft rotation angle sensor 36 is configured and arranged on the load side in the casing 34A, similarly to the drive device 1 described above. On the other hand, the high-speed shaft rotation angle sensor 35 is arranged on the anti-load side within the casing 34A to detect the rotation angle of the shaft 23, just like the drive unit 1 described above, but differs in that it is arranged on the anti-load side of the motor 20A.

[0046] The control device 40 controls the amount of movement of the motor 20A in the casing 34A, and the control configuration is the same as that of the drive device 1.

[0047] Therefore, in the case of the drive device 1A, when the motor 20A is driven, an input torque is applied to the shaft 23. This causes the high-speed rotor 31A of the magnetic modulation gear device 30 to rotate together with the shaft 23, and the spatial magnetic flux waveform of the internal pole magnet 31a of the high-speed rotor 31A is frequency-modulated by the magnetic pole piece 32a of the low-speed rotor 32, transmitting torque to the low-speed rotor 32. The output shaft 32b then rotates at a reduction ratio of (number of magnetic poles of the magnetic pole piece 32a of the low-speed rotor 32) / (number of pole pairs of the internal pole magnet 31a).

[0048] At this time, the phase difference output unit 41 of the control device 40 outputs a torque command T * The target phase difference θ of the output shaft 32b corresponding to * On the other hand, the phase difference calculation unit 42 calculates the phase difference θ_fb occurring in the output shaft 32b, and a subtractor 43 calculates the deviation θ_cmd of the phase difference of the output shaft 32b. Then, the operation amount determined based on the deviation θ_cmd is input to the motor 20A, and a torque command T * A target output torque corresponding to the target output torque is generated.

[0049] In the driving device 1A, the magnetic modulation gear device 30 and the motor 20A share a common casing 34A, and the internal configurations of the magnetic modulation gear device 30 and the motor 20A are disposed within the casing 34A. Therefore, the drive device 1A can obtain the same technical effects as the drive device 1, and can also realize a smaller and more compact device overall. Furthermore, since the internal structures of the magnetic modulation gear device 30 and the motor 20A are arranged within the same casing 34A, it becomes easier to share parts, such as making the rotor yoke 21b common between the motor rotor 21 and the high-speed rotor 31A, thereby simplifying the structure and reducing the number of parts.

[0050] [Third embodiment] A third embodiment of the present invention will be described with reference to the drawings. Fig. 5 is an axial cross-sectional view of a drive device 1B according to the third embodiment. The driving device 1B of the third embodiment will be described mainly in terms of the differences from the driving device 1A. As shown in Fig. 5, the driving device 1B differs from the driving device 1A in the configuration of a control device 40B.

[0051] The control device 40B includes a phase difference calculation unit 42 that calculates a phase difference θ_fb currently occurring in the output shaft 32b, a torque acquisition unit 41B that calculates an output torque T_fb currently occurring in the output shaft 32b from the phase difference θ_fb, and a torque command T that indicates a target output torque to be generated in the output shaft 32b. * and a subtractor 43B that receives an input of the output torque T_fb currently occurring in the output shaft 32b from the torque obtaining section 41B and calculates a deviation T_cmd of the output torque of the output shaft 32b. The above-described components of the control device 40B may be realized by hardware, or the control device 40B may be configured as an arithmetic processing device and may be functionally realized by software processing.

[0052] The phase difference calculation unit 42 calculates the phase difference θ_fb occurring in the output shaft 32b from the rotation angle of the shaft 23 detected by the sensor unit 352 of the high speed shaft rotation angle sensor 35 and the rotation angle of the output shaft 32b detected by the sensor unit 362 of the low speed shaft rotation angle sensor 36.

[0053] The torque obtaining unit 41B obtains the phase difference generated in the output shaft 32b of the low-speed rotor 32 and the phase difference generated in the output shaft 3 2b and the output torque generated in the motor 2b (see, for example, FIG. 3). The table data defines the value of the output torque generated on the output shaft 32b for each of a plurality of values ​​of the phase difference of the output shaft 32b. When the phase difference θ_fb generated on the output shaft 32b is input from the phase difference calculation unit 42, the torque obtaining unit 41B outputs the corresponding torque value defined in the table data as the output torque T_fb currently generated on the output shaft 32b. In other words, the phase difference calculation unit 42 and the torque acquisition unit 41B cooperate to function as a "torque estimation unit that estimates the output torque of the output shaft 32b from the rotation angle measured by the input shaft side sensor (high speed shaft rotation angle sensor 35) and the rotation angle measured by the output shaft side sensor (low speed shaft rotation angle sensor 36)."

[0054] Similarly, in the case of the table data, different table data is prepared for each of a plurality of rotation angles of the shaft 23. Furthermore, the table data for each rotation angle of the shaft 23 is prepared for each of a plurality of different temperatures, with the value of each output torque T_fb corrected in consideration of the influence of the ambient temperature. Therefore, the torque acquisition unit 41B selects appropriate table data based on the rotation angle of the shaft 23 detected by the sensor unit 352 of the high-speed shaft rotation angle sensor 35 and the detected temperature of the temperature sensor 37, and then identifies and outputs the output torque T_fb currently generated in the output shaft 32b.

[0055] The subtractor 43B calculates the torque command T * The output torque T_fb actually generated in the output shaft 32b output from the torque obtaining unit 41B is subtracted from the target output torque to calculate a deviation T_cmd of the output torque of the output shaft 32b. Furthermore, the deviation T_cmd is multiplied by a predetermined gain, and torque control is performed so that the multiplied value becomes the torque input from the motor 20A to the magnetic modulation gear device 30. As a result, the torque of the motor 20A is controlled so that an appropriate phase difference is generated on the output shaft 32b, and the torque command T * A target output torque corresponding to the target output torque is generated.

[0056] That is, the control device 40B performs the processing of the subtractor 43B to subtract the output torque (output torque T_fb) estimated by the phase difference calculation unit 42 and the torque acquisition unit 41B as the torque estimation unit from the target output torque (torque command T * The input torque of the drive source (motor 20A) is controlled based on the difference between the input torque and the output torque.

[0057] As described above, the drive unit 1B can easily obtain the output torque generated on the output shaft 32b from the outputs of the high-speed shaft rotation angle sensor 35 and the low-speed shaft rotation angle sensor 36 because the phase difference calculation unit 42 and the torque acquisition unit 41B in the control device 40B function as a torque estimation unit.

[0058] In addition, the control device 40B corrects the output torque required by the torque acquisition unit 41B based on the temperature of the outer pole magnet 33 of the magnetic modulation gear device 30 detected by the temperature sensor 37, so that the driving device 1B can perform more accurate torque control by reflecting the influence of temperature.

[0059] [Example of application to robots] An example of application of the driving device shown in the first to third embodiments to a robot will be described with reference to the drawings. Fig. 6 is a side view of a robot 100 which is the application example. The robot 100 includes a base 101, a plurality of arms 102 connected by joints 103, and a tool 104 held at the tip of each of the connected arms 102. Each joint 103 is provided with the drive unit 1 described above.

[0060] The driving device 1 in each joint 103 of the robot 100 is provided with a high speed shaft rotation angle sensor 35 and a low speed shaft rotation angle sensor 36. Therefore, it is possible to control the movement of each joint based on the detection of these angle sensors 35, 36, and arbitrarily control the position, movement, and movement speed of the tool 104. The driving device 1 of each joint 103 of the robot 100 can control the output torque of the output shaft 32b in each joint 103 based on the sensor outputs of the high-speed shaft rotation angle sensor 35 and the low-speed shaft rotation angle sensor 36 used for movement control. Therefore, by appropriately controlling the output torque individually in the drive unit 1 in each joint 103, it is possible to perform force sense control such as, for example, making the tool 104 of the robot 100 contact the workpiece W shown in FIG. 6 with a constant pressing force (target value), or making contact with the workpiece W with a constant pressing force (target value) while performing other work with the tool 104.

[0061] In the case of the robot 100, in order to perform force sense control, in order to link the motors 20 of the drive units 1 in each joint 103, instead of a configuration in which a control unit 40 is provided for each drive unit 1, a control unit that comprehensively controls each drive unit 1 may be provided. Alternatively, a configuration may be provided in which a higher-level control unit is provided to link the control units 40 of each drive unit 1. Furthermore, each joint 103 of the robot 100 is not limited to the above-mentioned driving device 1, and other driving devices 1A and 1B may be provided.

[0062] [others] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, in the above embodiment, the rotor magnet 21c of the motor 20A and the inner pole magnet 31a of the magnetic modulation gear device 30 form magnetic poles that are independent of each other. However, the field poles of the motor 20A and the magnetic poles of the high-speed rotor 31 of the magnetic modulation gear device 30 may be common.

[0063] Furthermore, in each of the drive units 1, 1A, 1B, both the high speed shaft rotation angle sensor 35 and the low speed shaft rotation angle sensor 36 are disposed inside the casing 34, 34A, but it is also possible to configure at least one of the high speed shaft rotation angle sensor 35 and the low speed shaft rotation angle sensor 36 to be disposed inside the casing 34, 34A. Even in this case, either the sensor 35 or 36 disposed inside is protected, making it possible to improve detection stability and device reliability.

[0064] Furthermore, although brushless motors have been exemplified as motors 20 and 20A, the type and structure thereof are not particularly limited, and may be, for example, a synchronous machine or an induction machine. Furthermore, in the magnetic modulation gear device 30 of each of the above embodiments, the external magnet 33 is used as the stator, and output is extracted from the low-speed rotor 32 having the magnetic pole pieces 32a. However, the magnetic pole pieces 32a may be fixed, and the external magnet 33 may be connected to a rotatable low-speed rotor, and output may be extracted from the low-speed rotor.

[0065] Furthermore, in each of the above embodiments, the magnetic modulation gear device 30 serving as a transmission is a reducer, but the magnetic modulation gear device 30 serving as a transmission may also be a speed increaser. In this case, it can be realized by appropriately changing the number of pole pairs of the outer magnet 33, the number of pole pairs of the inner magnet 31a, and the number of magnetic poles of the pole piece 32a. Alternatively, the torque of the motor 20 may be input from the output shaft 32b side, and high-speed rotation may be extracted from the shaft 23 side. In this case, the phase difference on the shaft 23 side can be obtained to detect or control the output torque on the shaft 23 side.

[0066] In the driving device 1B, the control device 40B includes a torque estimation unit (phase difference calculation unit 42 and Although the motor 20A has a function as a torque obtaining unit 41B) and a function for controlling the input torque of the motor 20A, these two functions may be executed by separate control devices. In this case, a control element consisting of a chip or the like that performs the function of a torque estimation unit may be provided in the magnetic modulation gear device 30 (or the magnetic modulation gear device 30 integrated with the motor 20A), making it possible for the magnetic modulation gear device 30 alone to detect the output torque.

[0067] In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0068] 1, 1A, 1B drive unit 20,20A motor (drive source) 23 Shaft (input shaft) 30 Magnetic modulation gear device 31,31A high speed rotor 31a Inner pole magnet 31b Rotor yoke 32 Low-speed rotor 32a Pole piece 32b Output shaft 33 outer pole magnet 33a York 34,34A Casing 35 High-speed shaft rotation angle sensor (input shaft side sensor) 36 Slow shaft rotation angle sensor (output shaft side sensor) 37 Temperature Sensor 40, 40B Control device 41 Phase difference output section 41B Torque acquisition unit 42 Phase difference calculation section 43,43B Subtractor 100 robots 103 Joints Ax center axis T * Torque Command T_fb Output torque T_cmd Output torque deviation θ * phase difference θ_fb Phase difference θ_cmdθ deviation

Claims

1. A magnetic modulation gear device having an input shaft and an output shaft whose speed is changed relative to that of the input shaft through a reduction section of a magnetic modulation gear, an input shaft side sensor that measures the rotation angle of the input shaft side; an output shaft side sensor that measures the rotation angle of the output shaft side; Equipped with a housing, At least the input shaft side sensor or the output shaft side sensor is provided in the internal space of the housing, A magnetic modulation gear device in which torque control is performed to control the torque of the output shaft by adjusting the torque input to the input shaft based on the rotation angle measured by the input shaft side sensor and the output shaft side sensor.

2. Both the input shaft side sensor and the output shaft side sensor are provided in the same space of the housing.

2. The magnetic modulation gear device according to claim 1.

3. a torque estimation unit that stores a correlation between a phase difference due to a delay in the rotation angle of the output shaft and an output torque, and estimates the output torque of the output shaft from the correlation, the rotation angle measured by the input shaft side sensor, and the rotation angle measured by the output shaft side sensor; 3. The magnetic modulation gear device according to claim 1 or 2.

4. The torque estimation unit corrects and estimates the output torque of the output shaft in accordance with the temperature of the magnet of the magnetic modulation gear device.

4. The magnetic modulation gear device according to claim 3.

5. The magnetic modulation gear device according to claim 3 or 4; a drive source that applies an input torque to the input shaft; a control device that controls the input torque of the drive source based on the difference between the output torque estimated by the torque estimation unit and a target output torque; A drive unit comprising:

6. The magnetic modulation gear device according to claim 1 or 2; a drive source that applies an input torque to the input shaft; a control device that controls an amount of operation of the drive source so that a target output torque is output from the output shaft based on the measured rotation angle of the input shaft side and the measured rotation angle of the output shaft side; A drive unit comprising:

7. The control device corrects the operation amount of the drive source for outputting the target output torque in accordance with the temperature of the magnet of the magnetic modulation gear device. The drive device according to claim 6.

8. A robot having the drive device according to any one of claims 5 to 7.

Images