JP5254605B2 - Drive device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a driving device including a gear unit and a plurality of motors, and a manufacturing method thereof. In particular, the present invention relates to a driving apparatus suitable for controlling a plurality of motors with a single motor driver and a method for manufacturing the same.

Patent Document 1 discloses a drive device including a gear unit and a plurality of motors. In the gear unit of Patent Document 1, a plurality of input shafts are engaged with a driven member. A motor rotating shaft (motor rotor) is engaged with each input shaft. The driven member is rotated by torque of a plurality of motors.
The gear unit has the following configuration. The gear unit includes an internal gear member, a carrier, a plurality of input shafts (crankshaft), and a driven member (external gear). The internal gear has an internal gear formed on the inner periphery. The carrier is arranged coaxially with the axis of the internal gear and is rotatably supported by the internal gear member. The crankshaft extends along the axis of the internal gear member and is rotatably supported by the carrier. An eccentric body is fixed to the crankshaft. The rotational axis of the eccentric body is offset from the axis of the crankshaft. The external teeth (external gears) of the driven member are in mesh with the internal gears. A plurality of through holes are formed in the circumferential direction of the external gear, and eccentric bodies are fitted into the through holes, respectively. Therefore, the external gear rotates eccentrically around the axis of the internal gear as the crankshaft rotates. A gear unit that obtains a reduction ratio by using an external gear that rotates eccentrically and an internal gear that meshes with the external gear may be called an eccentric oscillating gear unit.
In the drive device of Patent Document 1, the rotation shafts of the plurality of motors are engaged with the crankshaft. Further, the respective stators of the plurality of motors are fixed to the carrier of the gear unit. The rotation shafts of the plurality of motors are engaged with the external gear. The driven member (external gear) is driven by the resultant torque output by each motor.

Japanese Utility Model Publication No. 2-41748

In the drive device of Patent Document 1, each motor is driven independently. That is, the same number of motor drivers as the number of motors are used to individually control the rotation of each motor.
In a driving apparatus including a plurality of motors, if a motor driver having a sufficiently large output is prepared, a plurality of motors can be controlled by a single motor driver. In order to control a plurality of motors with a single motor driver, the plurality of motors may be electrically connected in parallel or in series.
When a plurality of motors are controlled by a single motor driver, currents of the same phase flow through all the motors. On the other hand, the rotor of each motor rotates in conjunction with a driven member (external gear). That is, the rotation shafts of the respective motors cannot be rotated individually independently of the other motors. When the rotor rotation angle of one motor is determined, the rotor rotation angles of the remaining motors are determined. That is, when the mechanical phase angle between the rotor and stator of one motor is determined, the phase angle between the rotor and stator of the remaining motor is determined. If currents of the same phase are passed through a plurality of motors whose mechanical phase angles of the rotor and the stator are not aligned, a difference occurs in the motor output torque. As a result, the torque applied to the external gear from the rotation shaft (output shaft) of each motor is biased.
The present invention addresses the above-described problems, and provides a drive device suitable for being controlled by a single motor driver while having a plurality of motors, and a method for manufacturing the same.

If the mechanical phase angles of the rotor and the stator are made equal for all the motors, the output torque of each motor can be made equal even if a plurality of motors are controlled by a single motor driver. However, conventionally, since each motor was controlled by an individual motor driver, there was no idea of aligning the mechanical phases of the rotor and the stator. On the other hand, since a plurality of motors are usually attached after the gear unit is completed, it is difficult to attach the motors while aligning the phases of the rotors and the stators of the plurality of motors.
The drive device according to the present invention is provided with an adjustment mechanism capable of individually adjusting the phase angle of the rotor and the stator of each motor while attaching the motor to the gear unit and maintaining the engagement between the driven member and the plurality of input shafts. In the conventional drive device, since a plurality of motors are not controlled by a single motor driver, it is not necessary to employ an adjustment mechanism that can individually adjust the phase angle between the rotor and the stator of each motor. The drive device of the present invention employs an adjustment mechanism that has not been conventionally required. By adopting a structure that is not conventionally employed, a drive device that is suitable for control by a single motor driver while having a plurality of motors is realized.

The drive device of the present invention includes a gear unit and a plurality of motors. The gear unit includes a driven member and a plurality of input shafts engaged with the driven member. The rotor of each motor is engaged with the input shaft. The drive device of the present invention is provided with an adjustment mechanism capable of individually adjusting the phase angle of the rotor and the stator of each motor while maintaining the engagement between the driven member and the plurality of input shafts.
The adjustment mechanism may typically be a joint that allows or prohibits relative rotation of the two members. Such a joint may be fitted between the input shaft and the rotation shaft, between the rotation shaft and the rotor, between the motor case and the gear unit, or between the motor case and the stator.
More specifically, the adjustment mechanism is as follows. The rotation shaft of the motor and the rotor are freely fitted. A fixing member straddling both the rotation shaft and the rotor can be attached. Without the fixing member, the rotor is rotatable with respect to the rotation axis. Even if the rotation shaft of the motor is engaged with the input shaft, the rotor can freely rotate, so that the phase angle between the rotor and the stator can be freely adjusted. If the fixing member is fixed after the adjustment is completed, the rotor is fixed to the rotating shaft. More specifically, the fixing member is provided with an oval through hole extending along the circumferential direction. The fixing member is non-rotatably attached to one of the rotor and the rotating shaft, and the fixing member and the other are fixed by passing bolts through the through holes of the fixing member. If the bolt is loosened, the rotor or the rotating shaft can rotate by the circumferential length of the through hole. Such an adjustment mechanism may be provided between the motor case and the stator. Various configurations can be considered for the adjustment mechanism.
By providing an adjustment mechanism, the above-described drive device attaches a motor to the gear unit, and adjusts the phase angle of the rotor and the stator individually while maintaining the engagement of the driven member and the plurality of input shafts. Can be aligned. That is, the phase can be adjusted by adjusting the phase angle of the rotor and the stator individually by the adjusting mechanism.

A typical configuration of the gear unit is as follows. The gear unit includes an internal gear member, a carrier, a plurality of input shafts (also referred to as a crankshaft), and a driven member (also referred to as an external gear). An internal gear is formed on the inner periphery of the internal gear member. The carrier is arranged coaxially with the axis of the internal gear and is rotatably supported by the internal gear member. Each crankshaft extends along the axis of the internal gear and is rotatably supported by the carrier. An eccentric body is fixed to each crankshaft. The external gear meshes with the internal gear at a position surrounded by the internal gear member. The external gear is formed with a plurality of through holes in the circumferential direction, and an eccentric body of a crankshaft is fitted in each through hole. Therefore, the external gear can rotate eccentrically around the axis of the case as the crankshaft rotates.
The rotor of each motor is engaged with the crankshaft. The stator of each motor is fixed to the carrier. In addition, as the “engagement between the rotor and the crankshaft”, the form in which the crankshaft also serves as the rotating shaft of the motor, the form in which the rotating shaft of the motor is coaxially fixed to the crankshaft, The form etc. which a crankshaft interlock | cooperates via a gearwheel etc. are mentioned.

  When the gear unit includes the above-described internal gear member, carrier, input shaft, and external gear, the “relative rotation angle between the input shaft and the rotor” and the “relative rotation angle between the carrier and the stator” If at least one of the motors can be adjusted individually for each motor, the phase angle between the rotor and the stator of each motor can be adjusted individually while maintaining the engagement between the driven member and the plurality of input shafts.

By aligning the mechanical phase angle of the rotor and stator for all motors, even if multiple motors are controlled by a single motor driver (ie, currents of the same phase flow through each motor), the motor output Torque can be made uniform. The torque applied to the driven member from the rotation shaft of each motor can be made uniform.
The drive device of the present invention is suitable for all of a plurality of motors being controlled by a single motor driver.

The present invention also provides a method of manufacturing a drive device in which the mechanical phase angles of the rotor and the stator are uniform in all motors.
This manufacturing method includes the following steps.
(1) First step of preparing a gear unit and a plurality of motors (2) Second step of applying the same phase current to each motor to align the phase angle of the rotor and stator (3) Fixing the motor to the gear unit Here, the gear unit includes a driven member and a plurality of input shafts engaged with the driven member.
In the second step, the stator and rotor of each motor are relatively rotated by the interaction between the permanent magnet and the electromagnet. The relative rotation of the rotor and stator stops at a position where the magnetic force balances. Since the current of the same phase is applied to all the motors, the phases of the rotor and the stator are stationary at the same position in all the motors. That is, the phase angle can be made uniform for all the motors. In this state, the motor is fixed to the gear unit (third step).
In the above manufacturing method, the phase angles of the rotor and the stator are aligned by all the motors by the magnetic force. The phase angles of the rotor and stator of a plurality of motors can be easily aligned at the same time.

Before assembling the motor to the gear unit, all the motors may be energized to align the phase angle. However, it is more efficient to align the motor phase angle after temporarily fixing the motor to the gear unit. Specifically, the following two steps are suitable.
Prior to the second step, the rotor of the motor is rotatably connected to the input shaft, and a temporary fixing step of fixing the stator of the motor to the gear unit is performed. At this time, in the third step, the rotor of the motor may be engaged with the input shaft.
Prior to the second step, a temporary fixing step of engaging the rotor of the motor with the input shaft and rotatably connecting the stator of the motor to the gear unit is performed. At this time, in the third step, the motor stator may be fixed to the gear unit.
In any process, the process after aligning the phase angles of the rotor and the stator is simplified.

  When the rotor is engaged with the input shaft and when the stator is fixed to the gear unit, a physical force acts between the gear unit and the motor. If any one of the temporary fixing steps is performed prior to the second step, the chance that a physical force acts between the gear unit and the motor after aligning the phase angles can be minimized. When the third step is performed, the possibility that the phase angle between the rotor and the stator is shifted can be reduced.

  It is a drive device that drives a driven member with a plurality of motors, and a drive device suitable for controlling all the motors with a single motor driver can be provided.

The features of the examples are described below.
(First Feature) Each motor has the same torque characteristics and is controlled by one motor driver.
(Second feature) An encoder that detects the rotation angle of the rotor is attached to only one of the motors. The encoder is not connected to other motors.
(Third feature) The rotor of each motor is directly connected to the crankshaft coaxially, and the stator of each motor is fixed to the carrier.
(Fourth feature) A pin extending along the rotation axis is provided on one of the rotation shaft and the rotor of the motor, and on the other side, the pin extends along the circumferential direction and is loosely fitted to the pin. A through hole is formed. The through hole has an oval shape that is long along the circumferential direction. Within the range of the circumferential length of the through hole, the rotor and the stator can be rotated relative to each other while prohibiting relative rotation between the rotating shaft of the motor and the stator. That is, the phase angle between the rotor and the stator can be adjusted.
(5th characteristic) In a temporary fix | stop process, while attaching a rotor to an input shaft rotatably, the stator of each motor is fixed to a carrier. At this time, in the third step, the rotor is fixed to the input shaft.

Embodiments will be described with reference to the drawings. In the embodiment, a gear unit including a speed reduction mechanism will be described as an example of the gear unit. However, the present invention can also be suitably applied to a drive device that includes a gear unit (such as a gear unit that amplifies the rotation of the motor) other than the gear unit that includes the speed reduction mechanism.
(First embodiment)
FIG. 1 shows a cross-sectional view of a drive device (also referred to as a speed reducer) 100 of this embodiment. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 shows a cross-sectional view of the reduction gear device 100 when viewed from a direction different from that in FIG. The cross-sectional view of FIG. 1 corresponds to a cross section taken along line II of FIG. 2, and the cross-sectional view of FIG. 3 corresponds to a cross section taken along line III-III of FIG. FIG. 4 shows an enlarged view of a region 61 surrounded by a broken line in FIG. For the sake of clarity, in FIG. 3, reference numerals are given only to portions that are unique to the cross-sectional view of FIG. 3, and reference numerals are omitted for components that are substantially the same as those in FIG.
As shown in FIG. 1, the speed reducer 100 includes a gear unit 1 and a motor unit 59. The motor unit 59 includes a plurality of motors 57a to 57d. In FIG. 1, only the motors 57a and 57c are shown, and the other motors 57b and 57d are not shown.

First, the gear unit 1 will be described.
The gear unit 1 includes an internal gear member 18, external gears (corresponding to an example of a driven member) 20X and 20Y, a plurality of crankshafts (corresponding to an example of an input shaft) 49, and a carrier. As will be described later, the carrier is formed of a carrier upper portion 4X and a carrier base 4Y. In the following description, the carrier upper portion 4X and the carrier base 4Y may be collectively referred to as the carrier 4. Further, as will be described later, the internal gear member 18 may be referred to as an output portion of the gear unit 1. A portion that rotatably supports the internal tooth member 18 may be referred to as a fixed portion. Specifically, the carrier 4 (the carrier upper portion 4X and the carrier base 4Y) corresponds to a fixed portion of the gear unit 1. In the following description, alphabetical subscripts may be omitted when describing an event common to substantially the same type of component in which a plurality exist.
As shown in FIG. 2, the internal tooth member 18 is ring-shaped, and a large number of internal teeth are formed along the inner periphery thereof. The internal gear member 18 has a different number of teeth from the external gear 20. An internal gear in which a large number of internal teeth pins (internal teeth) 22 are arranged is formed along the inner periphery of the internal gear member 18. In other words, it can be said that the internal gear member 18 itself constitutes an internal gear.
The external gear 20 rotates eccentrically while meshing with the internal tooth pin 22 of the internal gear member 18. That is, the external gear 20 revolves around the axis 18 </ b> M of the internal gear member 18. The axis 18M can be referred to as an axis of an internal gear formed by the group of internal teeth pins 22 and can also be referred to as an axis of the carrier 4 described later. A first through hole 60 is formed at the center of the external gear 20, and a cylindrical member 64 passes through the first through hole 60 (see also FIG. 1). A plurality of second through holes 68 a to 68 h are formed around the first through hole 60 of the external gear 20. Each of the second through holes 68 is formed on the same circumference. Although details will be described later, the eccentric portion 50 of the crankshaft 49 is fitted in the second through holes 68a, 68c, 68e, and 68g, and the inside of the second through holes 68b, 68d, 68f, and 68h is inside the carrier 4. The columnar part 5 has passed.

As shown in FIG. 3, the carrier upper portion 4 </ b> X and the carrier base 4 </ b> Y are fastened by a bolt 66 and constitute the carrier 4 of the gear unit 1 together. The carrier upper portion 4 </ b> X and the carrier base 4 </ b> Y are prohibited from relative rotation by the positioning pins 67. The carrier 4 is disposed inside the internal tooth member 18. In the speed reduction device 100, the carrier base 4Y is fixed to a base portion (for example, a turning portion of a robot, a base of a rotation device, or the like) with a bolt or the like (see also FIG. 1). That is, the carrier 4 (the carrier upper portion 4X and the carrier base 4Y) is restricted from rotating with respect to the base portion. As a result, the external gears 20X and 20Y are restricted from rotating with respect to the base. As described above, the internal gear member 18 rotates with respect to the external gears 20X and 20Y. Therefore, the carrier 4 corresponds to a fixed part of the reduction gear 100. The internal gear member 18 corresponds to an output unit that rotates with respect to the fixed unit (the carrier upper portion 4X and the carrier base 4Y) of the reduction gear 100. When the internal tooth member 18 is fixed to the base, the carrier 4 rotates with respect to the internal tooth member 18. In this case, the axis of the carrier 4 is equal to the axis 18M of the internal gear member 18. That is, the carrier 4 is disposed coaxially with the internal tooth member 18.
As shown in FIG. 1, a pair of angular ball bearings 16 </ b> X and 16 </ b> Y is disposed between the carrier 4 and the internal gear member 18. The internal ball member 18 is supported by the angular ball bearings 16X and 16Y so as to be rotatable with respect to the carrier 4 and not to be displaced in the thrust direction. In addition, it can be said that the carrier 4 is supported so as not to be displaceable in the thrust direction while being rotatable with respect to the internal gear member 18. In the present embodiment, the pair of angular ball bearings 16X and 16Y is disposed between the carrier 4 and the internal gear member 18, but a tapered roller bearing or the like may be used instead of the angular ball bearing.

The crankshaft 49 includes a shaft 54 and eccentric portions 50X and 50Y that are eccentric with respect to the axis 54M of the shaft 54. The shaft 54 has a shaft 54a and a shaft 54b. The shaft 54a and the shaft 54b are integrally formed. The shaft 54b can be said to be a part of the shaft 54, and can also be called a rotating shaft of a motor 57 described later. The axis 54M extends in parallel with the axis 18M of the internal tooth member 18 (also referred to as the axis of the carrier 4) 18M. That is, the crankshaft 49 extends along the axis 18 </ b> M of the carrier 4. A pair of tapered roller bearings 40X and 40Y is disposed between the carrier 4 and the crankshaft 49. The crankshaft 49 is supported by the tapered roller bearings 40X and 40Y so as to be rotatable with respect to the carrier 4 and not to be displaced in the thrust direction. In the angular ball bearing 16, reference numeral 8 indicates an inner ring, reference numeral 14 indicates an outer ring, reference numeral 12 indicates a rolling element (ball), and reference numeral 10 indicates a cage for holding the rolling element 12. In the tapered roller bearing 40, reference numeral 38 indicates an inner ring, reference numeral 32 indicates an outer ring, reference numeral 36 indicates a rolling element (roller), and reference numeral 34 indicates a cage that holds the rolling element 36.
The eccentric portion 50 is fitted into the second through holes 68a, 68c, 68e, 68g (see FIG. 2) via the needle roller bearing 46. In the needle roller bearing 46, reference numeral 44 indicates a rolling element, and reference numeral 42 indicates a cage that holds the rolling element 44.

As shown in FIG. 3, the columnar portion 5d of the carrier upper portion 4X passes through the second through hole 69 of the external gear 20X and the second through hole 68d of the external gear 20Y. As shown in FIG. 2, the carrier upper portion 4X has a plurality of columnar portions 5b, 5d, 5f, and 5h, and the second through holes 68b, 68d, which correspond to the respective columnar portions 5b, 5d, 5f, and 5h, Passes 68f and 68h. Although not shown, each of the columnar portions 5b, 5d, 5f, and 5h also passes through the corresponding second through hole 69 (see FIG. 3) of the external gear 20X. In FIG. 2, a hole for fitting the positioning pin 67 and a bolt hole (see FIG. 3) for fastening the bolt 66 are omitted.
Between the second through holes 68b, 68d, 68f, and 68h of the external gear 20Y and the columnar portions 5b, 5d, 5f, and 5h, there is an interval that allows the external gear 20Y to rotate eccentrically around the axis 18M. It is secured. Similarly, an interval that allows the external gear 20X to rotate eccentrically around the axis 18M is secured between the second through hole 69 of the external gear 20X and the corresponding columnar portion 5.

As described above, the crankshaft 49 has the eccentric portion 50 (the eccentric portions 50X and 50Y). The eccentric portion 50Y is fitted into the second through holes 68a, 68c, 68e, 68g (see FIG. 2) of the external gear 20Y via the needle roller bearing 46Y. In other words, a plurality of second through holes 68a, 68c, 68e, 68g into which the eccentric portion 50 of the crankshaft 49 is fitted are formed in the external gear 20Y. The eccentric part 50Y can rotate inside the second through holes 68a, 68c, 68e, 68g. Similarly, the eccentric portion 50X is fitted in the second through hole of the external gear 50X. That is, the plurality of crankshafts 49 are engaged with the external gear 20X. The plurality of crankshafts 49 are also engaged with the external gear 20Y.
As shown in FIG. 1, a stopper member 48 is disposed between the eccentric portion 50X and the tapered roller bearing 40X, and a stopper member 52 is disposed between the eccentric portion 50Y and the tapered roller bearing 40Y. The stop members 48 and 52 prevent the eccentric portions 50X and 50Y from being displaced in the direction of the axis 54M.

  In the crankshaft 49, the rotational axes of the eccentric portions 50X and 50Y are offset from the axis 54M. However, in the eccentric portions 50X and 50Y, the offset direction is opposite. That is, the rotation axis of the eccentric part 50X and the rotation axis of the eccentric part 50Y are always on the opposite side across the axis 54M. As a result, the external gear 20X and the external gear 20Y are always present at symmetrical positions with respect to the axis 18M of the internal gear member 18. Therefore, a relationship that ensures a rotational balance of the gear unit 1 is realized.

A center hole 4Xa penetrating the center is formed in the carrier upper portion 4X. The carrier base 4Y is formed with a center hole 4Ya penetrating the center. The cylindrical member 64 is fixed to the carrier upper portion 4X and the carrier base 4Y inside the center hole 4Xa and the center hole 4Ya. The cylindrical member 64 passes through both the first through holes 60X and 60Y of the external gears 20X and 20Y. Due to the inner peripheral surface 64a of the cylindrical member 64, the gear unit 1 includes the axis 18M of the internal tooth member 18 (output portion), and a member that rotates the output side (the internal tooth member 18 from the base side of the gear unit 1). A central through hole leading to the existing side) is formed. The gear unit 1 includes the rotation axis 18M of the output portion, and a central through hole that leads from the base side to the output side can be formed because the internal tooth member 18 is ring-shaped and the inner side of the internal tooth member 18 This is because the first through holes 60X and 60Y are formed at the center of the external gears 20X and 20Y that rotate eccentrically.
Here, the terms “fixed part” and “output part” of the gear unit 1 will be described. As will be described later, in the reduction gear 100, when the motor 57 is fixed to the carrier base 4Y and the rotor 56 of the motor 57 rotates, the internal gear member 18 rotates relative to the carrier 4 and the motor 57. In the present embodiment, the carrier 4 corresponds to the housing of the gear unit 1. Therefore, the internal tooth member 18 can be referred to as an output portion of the gear unit 1, and the carrier 4 can be referred to as a fixed portion of the gear unit 1.

  A pair of oil seals 6 </ b> X and 6 </ b> Y is disposed between the carrier 4 and the internal tooth member 18. An oil seal 30 is disposed between the carrier base 4Y and the shaft 54a of each crankshaft 49. The seal cap 2 is disposed on the upper portion of the carrier upper portion 4X. The oil seals 6X, 6Y, 30 and the seal cap 2 can prevent the oil inserted into the gear unit 1 from leaking to the outside.

Next, the mechanism of the speed reducer 100 will be described.
When the rotor 56 of the motor 57 rotates and the crankshaft 49 rotates around the axis 54M, the eccentric portion 50 rotates eccentrically. In other words, the rotation axis of the eccentric portion 50 revolves around the axis 54M. When the eccentric portion 50 rotates eccentrically, the external gear 20 rotates eccentrically around the axis 18 </ b> M of the internal tooth member 18. In other words, the center of the external gear revolves around the axis 18 </ b> M of the internal gear member 18.
Since the external gear 20 and the internal gear member 18 mesh with each other, when the external gear 20 rotates eccentrically, the internal gear member 18 rotates with respect to the external gear 20. As described above, since the rotation of the external gear 20 is restricted with respect to the fixed portion (carrier 4), the internal gear member 18 rotates with respect to the fixed portion (carrier 4). The internal tooth member 18 corresponds to the output member of the reduction gear 100. When the motor 57 is driven, the internal gear member 18 rotates with respect to the fixed portion (carrier 4). The rotation of the motor 57 is decelerated by the gear unit 1 and transmitted to the internal gear member 18. In other words, the output torque of the motor 57 is amplified by the gear unit 1 and transmitted to the internal gear member 18.
As shown in FIG. 2, in the reduction gear 100, the number of teeth of the external gear 20 is 51, and the number of teeth of the internal gear member 18 (the number of internal pins 22) is 26. Further, every other external tooth of the external gear 20 meshes with the internal tooth pin 22. Therefore, when the external gear 20 revolves around the axis 18M 52 times (26 × 2) (eccentric rotation), the internal tooth member 18 rotates around the axis 18M once (rotates). Further, as is apparent from FIG. 2, all the external teeth of the external gear 20 are in contact with the internal tooth pins 22. Therefore, a structure in which backlash is unlikely to occur between the external gear 20 and the internal gear member 18 is realized. Further, as shown in FIG. 1, both the external gears 20 </ b> X and 20 </ b> Y mesh with one internal tooth pin 22. Therefore, backlash is unlikely to occur between the external gear 20 and the internal gear member 18. The internal tooth pin 22 is not fixed to the internal tooth member 18. The internal tooth pin 22 is fitted in a groove formed in the internal tooth member 18 and can rotate within the groove.
It should be noted that the reduction ratio of the reduction gear 100 can be appropriately changed by adjusting the number of teeth of the external gear 20 and the number of teeth of the internal gear member 18 (the number of internal gear pins 22).

  As described above, the eccentric portion 50Y of each crankshaft 49 is fitted in the second through hole 68 of the external gear 20Y. Each crankshaft 49 is connected to a rotating shaft 54 b of the motor 57. Accordingly, the rotation shafts 54b of the respective motors 57 cannot rotate independently. That is, the rotor 56 of each motor 57 cannot rotate independently of the rotors 56 of the other motors 57. In other words, each rotor 56 of the motor 57 is engaged with the driven member (external gear 20 </ b> Y) via the crankshaft 49. The torque of all the motors 57 is transmitted to the external gear 20Y, and the external gear 20Y rotates eccentrically. The same applies to the external gear 20X.

Next, the motor unit 59 will be described.
The motor unit 59 includes motors 57a, 57b, 57c, and 57d (the motors 57b and 57d are not shown). Each of the plurality of motors 57 includes a stator 58 and a rotor 56. A permanent magnet 55 is formed on the surface of the rotor 56. The permanent magnet 55 will be described later. The rotor 56 is engaged with the shaft 54 of the crankshaft 49. As described above, the shaft 54 includes the shaft 54a and the shaft 54b. The shaft 54 b can also be referred to as the rotation axis of the motor 57. Therefore, it can be said that the rotation shaft of each motor 57 is directly connected to each crankshaft 49 coaxially. The axis of the rotor 56 is equal to the axis 54M of the shaft 54. The stator 58 is fixed to a stator fixing portion 63 extending from the carrier base 4Y. In other words, the stator 58 is fixed to the carrier 4. A motor case 65 is disposed outside the stator fixing portion 63. In other words, a plurality of motors 57 fixed to the stator fixing portion 63 are accommodated in the motor case 65.

An encoder (rotation angle sensor) 26 that detects the rotation angle of the rotor 56 is attached to one of the motors 57a to 57d. The encoders 26 are not connected to the other three motors 57b, 57c, and 57d. Although details of the encoder 26 will be described later, the motors 57a to 57d are feedback-controlled based on the output of the encoder 26 attached to the motor 57a.
Since the encoder 26 is not connected to the other three motors 57b, 57c and 57d, a brake (not shown) can be connected using the space. When the brake is connected only to the motor 57 to which the encoder 26 is not connected, the axial length of the reduction gear 100 can be shortened as compared with the case where both the encoder 26 and the brake are connected to the motor 57. Note that the servo lock of the motor 57 may be used in place of the brake without connecting the brake to all the motors 57.

  The motor 57 is disposed outside the cylinder extending in the axial direction through the central through hole of the gear unit 1. More precisely, the motor 57 is disposed outside the central through hole of the gear unit 1 when the speed reducer 100 is observed from the axial direction. In other words, the motor 57 is disposed outside the inner peripheral surface 64 a of the cylindrical member 64. By disposing the motor 57 in such a manner, it is possible to pass wiring, piping, or the like (not shown) through the through hole 64a of the cylindrical member 64 without being obstructed by the motor 57.

  As described above, the stator 58 is fixed to the carrier base 4Y of the gear unit 1, and the rotor 56 is connected to the shaft 54 of the crankshaft 49. The rotor 56 can rotate about the axis of the stator 58. The axis of the stator 58 is equal to the axis 54M of the crankshaft 49. That is, the shaft 54 and the rotor 56 rotate integrally.

The motor 57 will be described in detail with reference to FIG.
As described above, the motor 57 includes the rotor 56 and the stator 58. The motor 57 is a three-phase motor. A winding 80 is wound around the stator 58, and a permanent magnet 55 is formed on the surface of the rotor 56. The permanent magnet 55 may be fixed to the surface of the rotor 56 or may be embedded in the rotor 56. The stator 58 is fixed to the stator fixing portion 63. The rotor 56 can rotate around the axis of the stator 58. The rotor 56 and the shaft 54 b are fixed by a spline ring (sometimes referred to as a shaft fixing member) 72. More precisely, the spline 70 and the spline ring 72 formed on the shaft 54 b are spline-connected, and the spline ring 72 and the rotor 56 are fixed by bolts 74. The shaft 54b and the spline ring 72 are prohibited from rotating relatively.
Here, the fixed state of the spline ring 72 and the rotor 56 will be described. FIG. 5 shows the spline ring 72 observed from the direction of arrow A in FIG. As shown in FIG. 5, the spline ring 72 has a through hole 71 extending along the circumferential direction. The bolt 74 passes through the through hole 71 and fixes the spline ring 72 and the rotor 56 (see also FIG. 4). Therefore, the relative rotation angle of the rotor 56 with respect to the spline ring 72 can be adjusted within the range of the circumferential length of the through hole 71. In other words, the relative rotation angle of the rotor 56 with respect to the shaft 54b (a part of the input shaft 49) can be adjusted. Further, the spline ring 72 can be regarded as a part of the shaft 54b (also referred to as a motor rotation shaft), and the bolt 74 can be regarded as a pin extending along the rotation shaft 54b. In that case, the rotor 56 is provided with a pin 74 extending along the rotation shaft 54 b, and the through-hole 71 extending along the circumferential direction and loosely fitting on the pin 74 is formed on the rotation shaft 54 b. It can be said that
The rotor 56 is fixed to the shaft 54b via the spline ring 72.

If the relative rotation angle of the rotor 56 with respect to the spline ring 72 can be adjusted, the shaft 54 b and the rotor 56 can be connected in a state where the phase angles of the rotor 56 and the stator 58 are aligned by all the motors 57. That is, the spline ring 72 (or the through hole 71 formed in the spline ring 72) can also be referred to as an adjustment mechanism capable of adjusting the phase angle between the rotor 56 and the stator 58.
As shown in FIG. 1, the motor 57 c also has a rotor 56 and a shaft 54 b fixed by a spline ring 72. Although not shown, the same applies to the motors 57b and 57d. That is, the speed reduction device 100 is provided with an adjustment mechanism that can individually adjust the phase angle of the rotor 56 and the stator 58 of each of the motors 57a to 57d.

As shown in FIG. 4, the upper side of the paper surface of the rotor 56 is in contact with the step formed by the shaft 54a and the shaft 54b. Further, the lower side of the rotor 56 in the drawing is in contact with the rotor support member 76. The rotor support member 76 is fixed to the shaft 54b by bolts 78. The rotor 56 is prevented from being displaced in the direction of the axis 65M by the shaft 54a and the rotor support member 76. The rotor support member 76 rotates integrally with the shaft 54b.
The rotating portion 90 of the encoder 26 is fixed to the rotor support member 76 by bolts 78. Therefore, the rotating part 90 rotates integrally with the rotor support member 76 and rotates integrally with the shaft 54b. A slit plate 92 is formed in the rotating unit 90. The light receiving element 94 of the encoder 26 is fixed to the encoder support portion 98. The light emitting element 95 of the encoder 26 is fixed to the encoder support portion 98 by a bolt 96. The encoder support portion 98 is fixed to the stator holding portion 63 extending from the carrier base 4Y. That is, the light receiving element 94 and the light emitting element 95 are fixed to the carrier 4. A slit plate 92 is disposed between the light receiving element 94 and the light emitting element 95.
The rotation angle of the shaft 54b can be detected by the encoder 26.

  Although not shown, an encoder 26 attached to the motor 57a is connected to a controller that outputs a torque command to the motor driver. The controller controls the motor driver based on the detection value of the encoder 26. That is, the plurality of motors 57 are feedback-controlled based on the output of the encoder 26 attached to one motor 57a.

Next, the phase angle between the rotor 56 and the stator 58 will be described.
FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. For clarity of the drawing, the stator holding portion 63 and the motor case 65 are not shown in FIG. The motors 57a to 57d are arranged at equal intervals around the axis 18M of the internal tooth member 18 (see also FIG. 1). Reference numeral 54M represents the axis of the rotor 56, and reference numeral 90 represents an imaginary circle having the radius of the axis 18M and the axis 54M. As described above, the motors 57a to 57d have the same specifications. In the following description, parts common to the motors 57a to 57d are denoted by the same reference numerals and description thereof is omitted.
The motor 57 a includes a ring-shaped stator 58 and a rotor 56 disposed in the stator 58. The starter 58 includes nine pole pieces 58a to 58i. A winding 80U is wound around the pole pieces 58a, 58e and 58f. A winding 80W is wound around the pole pieces 58b, 58c and 58g. A winding 80V is wound around the pole pieces 58d, 58h and 58i. In the rotor 56, eight-pole permanent magnets N1 to N4 and S1 to S4 (permanent magnet 55 in FIG. 1) are arranged. The permanent magnets N1 to N4 are arranged with the same magnetic pole (N pole) facing outward. The permanent magnets S1 to S4 are arranged with the south pole facing outward. Each of the permanent magnets N1 to N4 and S1 to S4 is arranged such that the magnetic poles facing outward are alternated in the circumferential direction. In the motor unit 59, the phase angles of the rotor 56 and the stator 58 are the same for all the motors 57a to 57d. For example, in all the motors 57a to 57d, the pole piece 58a around which the winding 80U is wound and the intermediate portion of the permanent magnet N1 face each other.

  In the motor 57 of this embodiment, the winding 80U is wound around the pole pieces 58a, 58e and 58f, the winding 80W is wound around the pole pieces 58b, 58c and 58g, and the pole pieces 58d, 58h and 58i are wound around. Winding 80V is wound. Each of the windings 80U, 80W, and 80V is disposed at a symmetrical position with respect to the axis 54M. Therefore, the electromagnetic force generated between the rotor 56 and the stator 58 is substantially symmetric with respect to the axis 54M. The balance of the electromagnetic force when the rotor 56 is rotating becomes good, and problems such as vibration can be prevented from occurring.

  As described above, the motors 57a to 57d are controlled by one motor driver. Therefore, the same phase current flows in each phase of the motors 57a to 57d. In the motor unit 59, the phase angles of the rotor 56 and the stator 58 are the same for all the motors 57a to 57d. Therefore, all the motors 57a to 57d are electrically synchronized. The driven member (external gear 20) can be driven stably. In other words, by providing an adjustment mechanism (spline ring 72) that can adjust the phase angle between the rotor 56 and the stator 58, the plurality of motors 57a to 57d can be controlled by a single motor driver.

Next, a method for manufacturing the reduction gear (drive device) 100 will be described.
(First step)
First, the gear unit 1 described above, that is, the gear unit 1 in which a plurality of crankshafts 49 are engaged with the external gear 20X is prepared. The details of the process for manufacturing the gear unit 1 will not be described.

(Temporary fixing process)
The rotor 56 is temporarily fixed to the shaft 54b (a part of the crankshaft 49). Here, “temporarily fixed” means that the rotor 56 can freely rotate with respect to the shaft 54b. In other words, the rotor 56 is connected to the shaft 54b.
Next, the stator 58 is fixed to the stator fixing portion 63 extending from the carrier 4. In other words, the stator 58 is fixed to the carrier 4. Generally speaking, the stator 58 is fixed to the gear unit 1. The fixed position of the stator 58 is naturally a position surrounding the rotor 56. The stator 58 is fixed to the gear unit 1 coaxially with the rotor 56.
For all the motors 57, the rotor 56 is temporarily fixed and the stator 58 is fixed. Either the temporary fixing of the rotor 56 and the fixing of the stator 58 may be performed first or simultaneously.
When this step is completed, the rotor 56 can be rotated without rotating the crankshaft 49. That is, the phase of the rotor 56 and the stator 58 can be adjusted without rotating the crankshaft 49. Since all the crankshafts 49 are engaged with the external gear 20X, “without rotating the crankshaft 49” means that “the engagement between the external gear 20X and the plurality of crankshafts 49 is maintained. "Means.
In this step, the motor 57 is attached to the gear unit 1 although it is not perfect. In the sense that it is not complete, this step can be called a step of temporarily fixing the motor 57 to the gear unit 1.

(Second step)
A current having the same phase is applied to all the motors 57. Here, “applying current of the same phase” means applying the same current (DC may be applied) to the same phase (for example, U phase (winding 80U)). Since the rotor 56 can freely rotate with respect to the crankshaft 49, the rotor 56 is stationary at an electromagnetically neutral position by the magnetic force generated by the stator 58. Since the current of the same phase is applied to all the motors 57, the relative rotation angles of the stator 58 and the rotor 56 are the same in all the motors 57. That is, the phase angles of the rotor 56 and the stator 58 are the same for all the motors 57. The phase angles of the rotor 56 and the stator 58 are aligned by all the motors 57 without the crankshaft 49 rotating.

(Third step)
In this step, the crankshaft 49 and the rotor 56 that have been temporarily fixed are fixed.
First, the spline ring 72 is fixed to the shaft 54b. At this time, a position where a bolt hole of the rotor 56 (a hole for fixing the rotor 56 and the spline ring 72 through the through hole 71) is exposed to the through hole 71 (see FIG. 5) formed in the spline ring 72. Therefore, the spline ring 72 is fixed to the shaft 54b. Since the shaft 54b and the spline ring 72 are spline-coupled, the relative angle between them can only be determined discretely. However, since the circumferential length of the through hole 71 is larger than the diameter of the shaft portion of the bolt 74, the spline ring 72 can be fixed to the shaft 54 b at a position where the bolt hole is exposed in the through hole 71. Conversely, the circumferential length of the through hole 71 is sufficient if the bolt 74 can move by one pitch of the spline 70.
Finally, the rotor 56 is bolted to the spline ring 72 for all the motors 57. That is, the rotor 56 is fixed to the crankshaft 49. Since the stator 58 is already fixed to the carrier 4 (generally, the gear unit 1) in the temporary fixing step, fixing the motor 57 to the gear unit 1 is completed by fixing the rotor 56 to the crankshaft 49. . In other words, this third step can be said to be a step of fixing the motor 57 to the gear unit 1.
When this process is completed, the driving device 100 in which the phase angles of the rotor 56 and the stator 58 are aligned in all the motors 57 is completed.

The motor 57 is temporarily fixed to the gear unit 1 by the temporary fixing step. At this time, since free relative rotation between the shaft 54b and the rotor 56 is allowed, there remains room for each motor 57 to individually adjust the relative rotation between the rotor 56 and the stator 58. In this state, the second step is performed. The rotor 56 and the stator 58 of each motor 57 rotate relative to each other by the interaction between the permanent magnet 55 and the electromagnet 80. The relative rotation between the rotor 56 and the stator 58 stops at a position where the magnetic force is balanced. Since currents having the same phase are applied to all the motors 57, the phases of the rotor 56 and the stator 58 are stationary at the same position in all the motors 57. In this state, the rotor 56 is fixed to the shaft 54b (third step).
In the above manufacturing method, the motors 57a to 57d are temporarily fixed to the gear unit 1 while leaving room for individually adjusting the relative rotation of the rotor 56 and the stator 58. Therefore, the motors 57 a to 57 d can be positioned with respect to the gear unit 1 except for the phase angle of the rotor 56 and the stator 58. After positioning the motors 57a to 57d, the phases of all the motors 57a to 57d are aligned by the magnetic force. The geometric positional relationship between the gear unit 1 and the motors 57a to 57d and the electromagnetic phase relationship between the rotors 56 and the stators 58 of all the motors 57 can be accurately determined.

In the manufacturing method described above, the temporary fixing step is performed prior to the second step of applying current to the motor 57. In the third step following the second step, the fixing of the gear unit 1 and the motor 57 is completed simply by fixing the rotor 56 to the crankshaft 49. After aligning the phase angles of the rotor 56 and the stator 58 in the second step, the chance of physical force acting between the gear unit 1 and the motor 57 can be minimized. When the gear unit 1 and the motor 57 are fixed, the possibility that the phase angle between the rotor 56 and the stator 58 is shifted can be reduced.
In addition, by performing the temporary fixing process, the phase angle between the rotor 56 and the stator 58 can be increased in a state where all the motors 57 are attached to the gear unit 1 (the motor 57 is not completely fixed to the gear unit 1). Can be aligned. The work is easier than attaching the motor 57 to the gear unit 1 after aligning the phase angles of the motor 57.

In the above manufacturing method, the phase angle of the rotor 56 and the stator 58 is made uniform by applying the current of the same phase to all the motors 57 in the second step. The phase angles of the plurality of motors 57a to 57d can be aligned at a time.
In addition, when the third step is performed, the phase angle between the rotor 56 and the stator 58 does not shift because the phase angle between the rotor 56 and the stator 58 can be adjusted individually (the spline ring 72 is formed). This is because the through hole 71) is provided.

In the above manufacturing method, the rotor 56 is temporarily fixed and the stator 58 is fixed to the carrier 4 in the temporary fixing step. By temporarily fixing the rotor 56, relative rotation between the rotor 56 and the stator 58 is allowed without rotating the crankshaft 49. Conversely, the same effect can be obtained by engaging (fixing) the rotor 56 with the crankshaft 49 and temporarily fixing the stator 58 to the carrier 4. “Temporarily fixing the stator 58 to the carrier 4” means that the stator 58 is rotatably attached to the carrier 4. Regardless of which of the rotor 56 and the stator 58 is temporarily fixed, the “temporary fixing step” does not rotate the crankshaft 49 (in other words, the engagement between the external gear 20X and the plurality of crankshafts 49 is maintained). As it is, it means a process of attaching the motor 57 to the gear unit 1 while allowing relative rotation of the rotor 56 and the stator 58.
When the stator 58 is temporarily fixed in the temporary fixing step, the third step is a step of fixing the stator 58 to the carrier 4.

The manufacturing process of the reduction gear 100 preferably includes a temporary fixing process, but the temporary fixing process may be omitted. In that case, in the third step, a plurality of motors 57 in which the phase angles of the rotor 56 and the stator 58 are aligned are fixed to the gear unit 1. That is, for each motor 57 having the same phase angle, the rotor 56 is engaged with the crankshaft 49 and the stator 58 is fixed to the carrier 4 (gear unit 1).
Even if the temporary fixing step is omitted, the phase angle of the rotor 56 and the stator 58 can be made uniform at the same time by causing the currents of the same phase to flow through the plurality of motors 57. A plurality of motors 57 having the same phase angle can be fixed to the gear unit 1.

Here, an example in which the gear unit 1 and the motor unit 59 (motors 57a to 57d) are fixed without performing the second step will be described.
FIG. 7: has shown sectional drawing along the VI-VI line of 100 of the reduction gear which has not implemented the 2nd process. As is apparent from FIG. 7, the phase angles of the rotor 56 and the stator 58 are not equal in all the motors 57a to 57d. Specifically, in the motor 57a, the pole piece 58a around which the winding 80U is wound and the intermediate portion of the permanent magnet S1 face each other. In the motor 57b, the boundary between the pole piece 58a and the permanent magnets N1 and S1 faces each other. In the motor 57c, the pole piece 58a and the end of the permanent magnet S1 face each other. In the motor 57d, the intermediate portion between the pole piece 58a and the permanent magnet N1 is opposed.
When the phase angles of the rotor 56 and the stator 58 are not equal in all the motors 57a to 57d, the torque applied to the driven member (the external gear 20) is biased, or the rotation direction of the motors 57a to 57d is desired. Or a delay may occur when the rotation of the motors 57a to 57d is stopped.
As shown in FIG. 6, if the phase angle of the rotor 56 and the stator 58 is equal in all the motors 57a to 57d, the above-described problems can be prevented from occurring.

FIG. 7 also shows an example of a reduction gear that does not include an adjustment mechanism that can individually adjust the phase angle of the rotor 56 and the stator 58.
Even if the phase angles of the rotor 56 and the stator 58 are the same for all the motors 57a to 57d, if the gear unit 1 and the motors 57a to 57d are not fixed while maintaining the state, the phase angles of the rotor 56 and the stator 58 are all The motors 57a to 57d are not equal. That is, unless the fixing position of the spline ring 72 and the rotor 56 can be adjusted, as a result, the phase angles of the rotor 56 and the stator 58 are not equal in all the motors 57a to 57d.

Below, the speed reducer of another Example is shown. The reduction gear described in the following embodiment is a modification of the reduction gear 100. Therefore, only a different part from the speed reducer 100 is demonstrated. Specifically, the reduction gears of the following embodiments are different only in the configuration of the region 61 of the reduction gear 100. Therefore, only the configuration of the region 61 (corresponding to FIG. 4 of the speed reduction device 100) is shown. Moreover, description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the component substantially the same as the speed reducer 100, or the last 2 digits.
(Second embodiment)
FIG. 8 shows a partial cross-sectional view of the reduction gear 200. In reduction device 200, shaft 254 b and rotor 256 are fixed by bolts 274. Specifically, a step is formed between the shaft 254a and the shaft 254b. Therefore, by tightening the bolt 274, the rotor 256 abuts on the shaft 254a. The frictional force generated between the shaft 254a and the rotor 256 prevents the shaft 254b and the rotor 256 from rotating relative to each other and the rotor 256 from being displaced in the direction of the axis 54M. A friction plate 259 is disposed between the shaft 254a and the rotor 256, and the frictional force generated between the shaft 254a and the rotor 256 is increased.
The shaft portion of the bolt 274 passes through a bolt through hole 256a formed in the rotor 256 and is fixed to the shaft 254b. The diameter of the bolt through hole 256 a is larger than the diameter of the shaft portion of the bolt 274 and smaller than the diameter of the head portion of the bolt 274. When the bolt 274 is loosened, the shaft 254b and the rotor 256 can rotate relatively. Therefore, the phase angles of the rotor 256 and the stator 58 can be made uniform for all the motors 57 (second step), and the rotor 256 can be fixed to the shaft 254b (third step). When the bolt 274 is loosened, the shaft 254b and the rotor 256 rotate relatively, and when the bolt 274 is tightened, the relative rotation of the shaft 254b and the rotor 256 is restricted. It can also be said that the adjustment mechanism is adjustable.
A fixing member 276 is fixed to the rotor 256, and the rotating portion 90 of the encoder 26 is fixed to the fixing member 276. Therefore, the rotor 256 and the rotating part 90 of the encoder 26 (in other words, the shaft 254b and the rotating part 90) rotate integrally. The encoder 26 can detect the rotation angle of the rotor 256 (also the rotation angle of the shaft 254b). In the motor 257 to which the encoder 26 is not attached (see also FIG. 1), the fixing member 276 can be omitted.

  In the reduction gear 200, a friction plate 259 is disposed between the shaft 254a and the rotor 256. However, if the bolt 274 is tightened so that the shaft 254b and the rotor 256 do not rotate relative to each other, the friction plate 259 may not be disposed. That is, the friction plate 259 can be appropriately employed according to the torque applied to the shaft 254b.

(Third embodiment)
FIG. 9 shows a partial cross-sectional view of the reduction gear 300. In the speed reduction device 300, the shaft 354 b and the rotor 356 are fixed by the bolt 374. An inclined portion 373 is formed on the shaft 354b, and an inclined portion 356b is formed on the rotor 356. Therefore, when the bolt 374 is tightened, a frictional force is generated between the shaft 354b and the rotor 356. The frictional force prevents the shaft 354b and the rotor 356 from rotating relatively and the rotor 356 from being displaced in the direction of the axis 54M. When the bolt 374 is loosened, the shaft 354b and the rotor 356 can rotate relative to each other. Therefore, the inclined portion 373 of the shaft 354b and the inclined portion 356b of the rotor 356 can also be referred to as an adjustment mechanism capable of individually adjusting the phase angle of the rotor 356 and the stator 58.
The diameter of the bolt through hole 356a is larger than the diameter of the shaft portion of the bolt 374 and smaller than the diameter of the head portion of the bolt 374. A fixing member 276 is fixed to the rotor 356, and the rotating portion 90 of the encoder 26 is fixed to the fixing member. Therefore, the rotor 356 and the rotating part 90 of the encoder 26 rotate integrally. The rotation angle of the rotor 356 (the rotation angle of the shaft 354b) can be detected by the encoder 26. Further, the fixing member 376 can be omitted in the motor 357 to which the encoder 26 is not attached.

(Fourth embodiment)
FIG. 10 shows a partial cross-sectional view of the speed reducer 400. In the speed reducer 400, the shaft 454b and the rotor 56 are fixed by the screw portion 470 and the nut member 472 formed on the shaft 454b. When the nut member 472 is tightened, the rotor 56 comes into contact with the shaft 454a. As a result, the rotor 56 is sandwiched between the shaft 454a and the nut member 472, and the shaft 454b and the rotor 56 are prevented from rotating relative to each other and the rotor 56 is prevented from being displaced in the direction of the axis 54M. When the nut member 472 is loosened, the shaft 454b and the rotor 56 rotate relatively, and when the nut member 472 is tightened, the relative rotation between the shaft 454b and the rotor 56 is constrained. It can also be said that the adjustment mechanism is adjustable.
In the reduction gear 400, the rotating portion 90 of the encoder 26 is fixed to the nut member 472 by a bolt 478. Therefore, the rotor 56 and the rotating part 90 of the encoder 26 rotate integrally.

(5th Example)
FIG. 11 shows a partial cross-sectional view of the speed reducer 500. Here, an example in which an encoder is not connected to the motor 557 will be described.
In the reduction gear 100, the rotor support member 76 prohibits the rotor 56 from being displaced in the direction of the axis 54M (see FIG. 1). Therefore, the rotor support member 76a is also attached to the motor 57c to which the encoder 26 is not attached.
On the other hand, in the reduction gear 500, the retaining ring 575 prohibits the rotor 56 from being displaced in the direction of the axis 54M. Compared with the rotor support member 76a of the reduction gear 100, the rotor 56 can be prohibited from being displaced in the direction of the axis 54M with a simple structure.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

In the above embodiment, an example in which the relative rotation angle of the rotor with respect to the input shaft can be individually adjusted for each motor has been described. However, the relative rotation angle of the carrier with respect to the stator may be individually adjustable for each motor. Further, both features may be provided.
In the above embodiment, the example in which the rotor of the motor and the input shaft are directly connected has been described. The rotating shaft (output shaft) of the motor may be engaged with the input shaft via a gear or the like.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Sectional drawing (1) of the reduction gear of 1st Example Sectional view along the line II-II in FIG. Sectional drawing (2) of the speed reducer of 1st Example Enlarged view of region 61 of FIG. Plan view seen from arrow A in FIG. Sectional view along line VI-VI in FIG. 6 is a modification of the cross-sectional view of FIG. Partial sectional view of the reduction gear of the second embodiment Partial sectional view of the reduction gear of the third embodiment Partial sectional view of the reduction gear of the fourth embodiment Partial sectional view of the reduction gear of the fifth embodiment

Explanation of symbols

1: Gear unit 4: Carrier 18: Internal tooth member 20: Driven member (external gear)
49: Input shaft (crankshaft)
54: Shaft (rotary shaft of motor)
56: Rotor 57: Motor 58: Stator 72: Adjustment mechanism (spline ring)
100: Drive device (decelerator)

Claims (7)

A drive unit comprising a gear unit and a plurality of motors;
The gear unit
An internal gear member having an internal gear formed on the inner circumference;
A carrier that is disposed coaxially with the axis of the internal gear and is rotatably supported by the internal gear member;
A plurality of input shafts extending along the axis of the internal gear and rotatably supported by the carrier, to which the eccentric body is fixed;
An external tooth meshing with an internal gear is formed, each of which is provided with a driven member formed with a plurality of through holes into which the eccentric body is fitted ,
The rotor of each motor is engaged with the input shaft, and the stator of each motor is fixed to the carrier .
While maintaining the engagement of the driven member and multiple input shafts , at least one of the "relative rotation angle of the input shaft and rotor" and the "relative rotation angle of the carrier and stator" can be adjusted individually for each motor. A drive device comprising an adjustment mechanism.   The drive device according to claim 1, wherein the phase angle of the rotor and the stator is the same for all motors. All of the plurality of motors, drive device according to claim 1 or 2, characterized in that it is controlled by one motor driver. A method of manufacturing a drive device including a gear unit and a plurality of motors,
A first step of preparing a gear unit comprising a driven member and a plurality of input shafts engaged with the driven member;
Applying a current of the same phase to each motor to align the phase angle of the rotor and the stator;
A third step of fixing the motor to the gear unit;
A method for manufacturing a drive device, comprising: Prior to the second step, the rotor of the motor is rotatably connected to the input shaft, and a temporary fixing step of fixing the stator of the motor to the gear unit is provided.
5. The method of manufacturing a drive device according to claim 4 , wherein the third step is a step of engaging a rotor of a motor with an input shaft. Prior to the second step, the motor includes a temporary fixing step of engaging the rotor of the motor with the input shaft and rotatably connecting the stator of the motor to the gear unit.
5. The method of manufacturing a drive device according to claim 4 , wherein the third step is a step of fixing a stator of the motor to the gear unit. The gear unit is
An internal gear member having an internal gear formed on the inner circumference;
A carrier that is disposed coaxially with the axis of the internal gear and is rotatably supported by the internal gear member;
A plurality of input shafts extending along the axis of the internal gear and rotatably supported by the carrier, to which the eccentric body is fixed;
An external tooth meshing with an internal gear is formed, each of which is provided with a driven member formed with a plurality of through holes into which the eccentric body is fitted,
Method for producing a drive apparatus according to any one of claims 4 to 6 in which the motor stator is characterized in that it is fixed to the carrier.

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