gear motor
A modular gear motor design with interchangeable detector sections addresses the cost issue of producing multiple types by allowing component sharing and flexible detector configurations, reducing manufacturing and design costs while enhancing operational flexibility.
Patent Information
- Application Number
- JP2021041994
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-03-16
- Publication Date
- 2025-09-19
- Estimated Expiration
- 2041-03-16
AI Technical Summary
The need to produce multiple types of gear motors for different detector combinations increases manufacturing costs, as each customer requires a specific configuration, leading to inefficiencies in production.
A modular gear motor design that incorporates a first detector arrangement section for a rotor shaft rotation detector, a second detector arrangement section for an output member rotation detector, and a third detector arrangement section for a torque detector, allowing for flexible configuration and sharing of core components across various types of gear motors.
This design reduces manufacturing and design costs by enabling the sharing of core components among gear motors with different detector configurations, facilitating plug-and-play integration of detectors, and improving operational flexibility.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a gear motor. [Background technology]
[0002] Patent Document 1 discloses a gear motor including a rotor shaft, an output shaft, a first rotation detector that detects rotation of the rotor shaft, and a second rotation detector that detects rotation of the output shaft. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] International Publication No. 2012 / 050130 Summary of the Invention [Problem to be solved by the invention]
[0004] The detectors that need to be incorporated into gear motors vary depending on the customer. If a dedicated gear motor were to be designed for each combination of detectors required by the customer, multiple types of gear motors would need to be prepared individually according to the number of detector combinations required. This increases manufacturing costs, so an improvement in this area is desirable.
[0005] One of the objects of the present disclosure is to provide a technology that can reduce manufacturing costs when handling multiple types of gear motors. [Means for solving the problem]
[0006] The gear motor of the present disclosure is a gear motor comprising a motor and a reducer, and is provided with a first detector arrangement section in which a first rotation detector that detects the rotation of a rotor shaft is arranged, a second detector arrangement section in which a second rotation detector that detects the rotation of an output member of the reducer is arranged, and a third detector arrangement section in which a torque detector is arranged, and this gear motor can operate when the first rotation detector is arranged in the first detector arrangement section, the second rotation detector is arranged in the second detector arrangement section, and the torque detector is arranged in the third detector arrangement section, or when a part of them is arranged. [Effects of the Invention]
[0007] According to the present disclosure, manufacturing costs can be reduced when dealing with multiple types of gear motors. [Brief explanation of the drawings]
[0008] [Figure 1] 1 is a side cross-sectional view of a gear motor according to a first embodiment. [Figure 2] Figure 2(a) is a schematic diagram of a gear motor of the first embodiment, Figure 2(b) is a schematic diagram of a gear motor of the first modified form, Figure 2(c) is a schematic diagram of a gear motor of the second modified form, and Figure 2(d) is a schematic diagram of a gear motor of the third modified form. [Figure 3] FIG. 2 is a side cross-sectional view showing a part of the shaft body of the first embodiment together with the surrounding structure. [Figure 4] FIG. 2 is a side cross-sectional view showing the base housing of the first embodiment. [Figure 5] FIG. 5(a) shows the motor housing used for the first motor, FIG. 5(b) shows the motor housing used for the second motor, and FIG. 5(c) shows the motor housing used for the third motor. [Figure 6] 2 is a diagram showing the peripheral structure of the internal bearing of FIG. 1. [Figure 7] FIG. 2 is a side cross-sectional view showing wiring used in the gear motor of the first embodiment together with the surrounding structure. [Figure 8] 8 is a cross-sectional view taken along the line AA in FIG. 7. [Figure 9]FIG. 2 is a perspective view showing a driver unit used in the gear motor of the first embodiment together with the surrounding structure. [Figure 10] 10 is a side cross-sectional view showing a part of the BB section of FIG. 9. [Figure 11] 10 is a side cross-sectional view showing a part of the CC cut surface of FIG. 9. [Figure 12] 2 is a side cross-sectional view showing a heat sink used in the gear motor of the first embodiment together with the surrounding structure. FIG. [Figure 13] FIG. 10 is a partial side cross-sectional view showing an industrial robot in which a gear motor according to a second embodiment is used. [Figure 14] FIG. 14 is a diagram showing a part of the cross section DD of FIG. 13. DETAILED DESCRIPTION OF THE INVENTION
[0009] The following describes the embodiments. Identical components are designated by the same reference numerals, and redundant explanations will be omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for the sake of convenience. The drawings should be viewed in accordance with the orientation of the reference numerals.
[0010] (First embodiment) Refer to FIG. 1. A gear motor 10 connects a first mating member 12 and a second mating member 14. The gear motor 10 can rotate the second mating member 14 relative to the first mating member 12. The gear motor 10 of this embodiment is incorporated into a joint of an industrial robot. The first and second mating members 12 and 14 of this embodiment are formed by either a base member or an arm member of an articulated arm.
[0011] The gear motor 10 mainly includes a motor 16, a rotor shaft 18 rotated by the motor 16, a reducer 20 that reduces the rotation of the rotor shaft 18, and a housing 22 that accommodates a reduction mechanism 42 of the reducer 20 and the motor 16. The gear motor 10 of this embodiment also includes a detection shaft 24 that passes through the input shaft 40 of the reducer 20 and the rotor shaft 18, and a driver unit 26 that is disposed on the anti-load side of the motor 16. The gear motor 10 of this embodiment further includes a first rotation detector 28 that detects the rotation of the rotor shaft 18, a second rotation detector 30 that detects the rotation of an output member 48 of the reducer 20, and a torque detector 32 that detects the torque of a shaft 31 consisting of the rotor shaft 18 and the input shaft 40. The gear motor 10 of this embodiment also includes a brake 34 that brakes the shaft 31. The first mating member 12 is integrated with the housing 22 using screws or the like, and the second mating member 14 is integrated with the carrier 44 of the reducer 20 using screws or the like.
[0012] Hereinafter, the direction along the rotation center line CL of rotor shaft 18 will be referred to as the axial direction X, and the circumferential direction and radial direction of a circle centered on the rotation center line CL will be referred to as the "circumferential direction" and the "radial direction," respectively. Furthermore, the side in the axial direction X from motor 16 toward reducer 20 (the left side in FIG. 1) will be referred to as the load side, and the opposite side in the axial direction X (the right side in FIG. 1) will be referred to as the anti-load side.
[0013] The motor 16 includes a stator 36 fixed to a motor housing 60 of the housing 22, and a rotor 38 that rotates integrally with the rotor shaft 18. The rotor shaft 18 passes through the motor 16 in the axial direction X.
[0014] The reducer 20 includes an input shaft 40 to which the rotation of the rotor shaft 18 is input, and a reduction mechanism 42 that reduces the rotation of the input shaft 40. In addition, the reducer 20 includes a carrier 44 that is disposed on the axial load side of the reduction mechanism 42, a reduction mechanism housing 47 that accommodates the reduction mechanism 42, and an output member 48 that outputs the reduced rotation from the reduction mechanism 42.
[0015] The reduction mechanism 42 of this embodiment is a flexible mesh gear mechanism in which the input shaft 40 flexibly deforms the external gear 50, causing the internal gear to rotate, and the rotation component is extracted by the output member 48. The reduction mechanism 42 of this embodiment is a cylindrical flexible mesh gear mechanism that uses a first internal gear 52 whose relative rotation with respect to the reducer housing 47 is restricted, and a second internal gear 54 that is rotatable relative to the reducer housing 47.
[0016] The input shaft 40 is provided with a gear drive unit 40a that drives a gear (external gear 50) of the reduction mechanism 42. The gear drive unit 40a of the input shaft 40 used in the flexible mesh gear mechanism has an elliptical shape in a cross section perpendicular to the axial direction X. Here, the term "elliptical shape" includes not only a geometrically strict elliptical shape but also an approximate elliptical shape.
[0017] The reduction mechanism 42 includes an external gear 50 disposed on the outer periphery of the input shaft 40, and first and second internal gears 52, 54 that mesh with the external gear 50. The external gear 50 is rotatably supported on the input shaft 40 via a first external bearing 110 that is disposed between the gear drive portion 40a of the input shaft 40 and the external gear 50. The external gear 50 of this embodiment is flexible, and is flexibly deformed to form an elliptical shape that matches the gear drive portion 40a of the input shaft 40 when the input shaft 40 rotates.
[0018] The first internal gear 52 is disposed on the anti-load side. The second internal gear 54 is disposed on the load side. The first internal gear 52 has a number of internal teeth (e.g., 102) different from the number of external teeth (e.g., 100) of the external gear 50, and the second internal gear 54 has a number of internal teeth equal to the number of external teeth of the external gear 50. In the reduction gear mechanism 42 of this embodiment, the external gear 50 rotates together with the second internal gear 54 by an amount corresponding to the difference in the number of teeth between the external gear 50 and the first internal gear 52 every time the input shaft 40 rotates once.
[0019] The carrier 44 has an annular shape as a whole. The carrier 44 has a through hole 45 that passes through the center of the carrier 44 and a mating protrusion 46 that protrudes toward the load side. The carrier 44 is integrated with the second internal gear 54 by fitting the mating protrusion 46 into a mating recess 54a provided in the second internal gear 54.
[0020] The reducer housing 47 of this embodiment includes a first housing member 44A that also serves as the first internal gear 52, and a second housing member 44B that is disposed radially outward of the second internal gear 54. The first housing member 44A and the second housing member 44B are integrated with each other by screws or the like. A main bearing 58 is disposed between the reducer housing 47 and the second internal gear 54.
[0021] The output member 48 of this embodiment is the carrier 44, which outputs the rotation extracted from the reduction mechanism 42 to the second mating member 14.
[0022] The housing 22 includes the aforementioned reducer housing 47 that houses the speed reduction mechanism 42, and a motor housing 60 that houses the motor 16. The reducer housing 47 is integrated with the motor housing 60 using bolts or the like.
[0023] The motor housing 60 has a cylindrical shape as a whole. The motor housing 60 of this embodiment is an integrally molded product obtained by integral molding and is composed of a single member. The motor housing 60 of this embodiment is an integrally molded product that is a die-cast product made of aluminum (metal). Alternatively, the motor housing 60 may be a machined product made of metal, for example.
[0024] The motor housing 60 includes a stator mounting portion 62 in which the stator 36 is mounted, and an inner flange portion 64 provided on the anti-load side of the stator mounting portion 62. The stator 36 is fixed to the stator mounting portion 62 using adhesive, fitting, or the like. The inner flange portion 64 protrudes radially inward from the inner periphery of the motor housing 60. The motor housing 60 also includes a portion (a housing-side portion 106a, described below) of a brake mounting portion 106 in which the brake 34 is mounted. The housing-side portion 106a is provided between the stator mounting portion 62 and the inner flange portion 64.
[0025] In addition to the shaft body 31, the detection shaft 24 passes through a through-hole 45 of the output member 48 (carrier 44) in the axial direction X. The detection shaft 24 is fixed to the output member 48 and is provided so as to be rotatable integrally with the output member 48. More specifically, the load side end of the detection shaft 24 is tightly fitted into the through-hole 45 of the output member 48, thereby being fixed to the output member 48. This allows the detection shaft 24 to be fixed to the output member 48 while its axial position relative to the output member 48 is adjustable.
[0026] The driver unit 26 includes a control board 70 that constitutes a control unit 68 incorporating a driver circuit, a sensor board 72 that mounts sensors 28B, 30B (described later) of the rotation detectors 28, 30, and a board holder 74 that holds the boards 70, 72. The sensor board 72 is electrically connected to the control unit 68 of the control board 70 via wiring (not shown). The control unit 68 is capable of driving the motor 16 to rotate the rotor shaft 18.
[0027] In this embodiment, the first and second rotation detectors 28, 30 are rotary encoders. The first rotation detector 28 includes a first detectable member 28A that can rotate integrally with the rotor shaft 18 and a first sensor 28B that can detect the first detectable member 28A. The second rotation detector 30 includes a second detectable member 30A that can rotate integrally with the output member 48 and a second sensor 30B that can detect the second detectable member 30A. When the rotation detectors 28, 30 are rotary encoders, the detectable members 28A, 30A are encoder disks, and the sensors 28B, 30B are, for example, optical sensors or magnetic sensors. The rotation detectors 28, 30 can detect the rotation of the target (rotor shaft 18, output member 48) by detecting the detectable members 28A, 30A with the sensors 28B, 30B. The combination of the detectable members 28A, 30A and the sensors 28B, 30B that constitute the rotation detectors 28, 30 is not limited to this. The rotation detectors 28 and 30 are not limited to rotary encoders, and various rotation detectors can be used, such as resolvers and Hall elements.
[0028] The first detected member 28A is disposed at the counter-load side end 18a of the rotor shaft 18. The second detected member 30A is disposed at the counter-load side end 24a of the detection shaft 24, which rotates integrally with the output member 48. The first and second sensors 28B, 30B are disposed in a position facing the first and second detected members 28A, 30A in the axial direction X. In this embodiment, they are mounted on a sensor board 72 of the driver unit 26. The counter-load side end faces of the first and second detected members 28A, 30A are aligned in the axial direction X. The load side end faces of the first and second sensors 30B are aligned in the axial direction X with respect to the sensor board 72.
[0029] The torque detector 32 in this embodiment is a strain sensor such as a strain gauge attached to a strain member 76 that generates strain according to the torque of the shaft body 31. The torque detector 32 is not limited to a strain gauge as long as it is capable of detecting torque. The strain member 76 in this embodiment is the first internal gear 52 to which the torque of the shaft body 31 is transmitted from the shaft body 31 via the external gear 50. The torque detector 32 is attached to a side portion of the first internal gear 52 that is on the anti-load side in the axial direction X. In this embodiment, although not shown, multiple torque detectors 32 are attached to the first internal gear 52 at intervals in the circumferential direction.
[0030] The torque detector 32 detects the distortion of the distortion member 76 and obtains a detection signal indicating the amount of distortion. The torque detector 32 outputs the obtained detection signal to a signal processing unit (not shown). The signal processing unit processes the detection signal output from the torque detector 32 to detect the torque of the distortion member 76. The signal processing unit may detect the torque of the shaft body 31, for example, by referring to a data table that uniquely associates the amount of distortion of the distortion member 76 with the torque of the shaft body 31. There are no particular limitations on the type of control performed based on the detected torque. For example, the signal processing unit may detect contact of an obstacle (e.g., a person) with the second mating member 14 based on the detected torque and perform control to stop the motor 16. Alternatively, it may perform control to press the second mating member 14 against an external member with a predetermined pressing force. The signal processing unit may be incorporated into either the torque detector 32 or the control unit 68 of the driver unit 26.
[0031] The brake 34 is provided on the load side of the motor 16. The brake 34 is provided between the motor 16 and the reducer 20. The brake 34 includes a brake mechanism 80 that brakes the rotating member 78, and a brake body 82 that mounts the brake mechanism 80. The brake body 82 supports the brake mechanism 80 and is fixed to the housing 22. The rotating member 78 in this embodiment is separate from the shaft body 31, and is attached to the shaft body 31 as part of the brake 34. Alternatively, the rotating member 78 may be the shaft body 31 itself, in which case it is provided separately from the brake 34. The brake 34 in this embodiment is a disc brake, and the rotating member 78 is a disc-shaped brake rotor.
[0032] The brake mechanism 80 includes a movable friction member 84 that brakes the rotating member 78 by friction, and a pressing mechanism 86 that presses the friction member 84 toward the rotating member 78. The brake mechanism 80 of this embodiment includes a fixed friction member 88 that is provided on the axially opposite side of the rotating member 78 from the movable friction member 84. The movable friction member 84 is supported by a guide pin (not shown) so as to be guided in the axial direction X. The fixed friction member 88 is fixed to the brake body 82 via the guide pin (not shown).
[0033] The pressing mechanism 86 is an electric type that uses electricity to drive the movable friction member 84. More specifically, the pressing mechanism 86 includes a biasing member (not shown), such as a spring, that biases the movable friction member 84, and a coil 90 that drives the movable friction member 84 in the axial direction opposite to the biasing direction of the biasing member. The movable friction member 84 is an armature, and is driven by an attractive force resulting from a magnetic force generated by the coil 90.
[0034] When the coil 90 is de-energized, the brake mechanism 80 uses the biasing member to press the movable friction member 84 against the rotating member 78, thereby braking the rotating member 78 through friction of the movable friction member 84. At this time, the brake mechanism 80 of this embodiment brakes the rotating member 78 by sandwiching the rotating member 78 between the movable friction member 84 and the fixed friction member 88. When the coil 90 is energized, the brake mechanism 80 drives the movable friction member 84 by the coil 90 to move away from the rotating member 78, thereby releasing the braking of the rotating member 78 by the movable friction member 84.
[0035] The gear motor 10 comprises a first detector arrangement portion 100 in which the first rotation detector 28 is arranged, a second detector arrangement portion 102 in which the second rotation detector 30 is arranged, a third detector arrangement portion 104 in which the torque detector 32 is arranged, and a brake arrangement portion 106 in which the brake 34 is arranged.
[0036] The first detector arrangement portion 100 of this embodiment includes a first shaft-side portion 100a provided at the anti-load-side end 18a of the rotor shaft 18, and a first opposing portion 100b provided at a position opposing the first shaft-side portion 100a. The first opposing portion 100b of this embodiment is provided on the sensor substrate 72 at a position opposing the first shaft-side portion 100a in the axial direction. A first detected member 28A of the first rotation detector 28 is arranged in the first shaft-side portion 100a, and a first sensor 28B of the first rotation detector 28 is arranged in the first opposing portion 100b.
[0037] The second detector arrangement portion 102 of this embodiment includes a second shaft-side portion 102a provided at the anti-load-side end 24a of the detection shaft 24, and a second opposing portion 102b provided at a position opposing the second shaft-side portion 102a. The second opposing portion 102b of this embodiment is provided on the sensor substrate 72 at a position opposing the second shaft-side portion 102a in the axial direction X. The second detection target member 30A of the second rotation detector 30 is disposed in the second shaft-side portion 102a, and the second sensor 30B of the second rotation detector 30 is disposed in the second opposing portion 102b.
[0038] The third detector arrangement portion 104 of this embodiment is provided on the above-mentioned first internal gear 52. More specifically, it is provided on the side of the first internal gear 52 in the axial direction X on the anti-load side.
[0039] The brake arrangement portion 106 of this embodiment includes a housing-side portion 106a provided on the inner periphery of the housing 22, and a third-shaft-side portion 106b provided on the outer periphery of the rotor shaft 18. The third-shaft-side portion 106b is provided integrally with the rotor shaft 18. The third-shaft-side portion 106b is provided as part of the single rotor shaft 18. A brake main body 82 that becomes part of the brake 34 is disposed in the housing-side portion 106a, and a rotating member 78 that becomes part of the brake 34 is disposed in the third-shaft-side portion 106b. The brake main body 82 is fixed to the housing-side portion 106a by fitting, which involves press-fitting, into the housing-side portion 106a.
[0040] The rotating member 78 is fixed to the third shaft side portion 106b by a splined fit so as to be movable in the axial direction X (integrated with the third shaft side portion 106b in the rotational direction). A male spline is provided on the third shaft side portion 106b, and a female spline is provided on the inner periphery of the rotating member 78. There are no particular limitations on the means for fixing the rotating member 78 to the third shaft side portion 106b, and for example, a fit involving press fitting without using a spline may be used.
[0041] The gear motor 10 can operate when the first rotation detector 28 is arranged in the first detector arrangement section 100, the second rotation detector 30 is arranged in the second detector arrangement section 102, and the torque detector 32 is arranged in the third detector arrangement section 104, or when some of them are arranged. "When some of them are arranged" means that at least one of the first and second rotation detectors 28, 30 and the torque detector 32 is arranged in the corresponding arrangement section 100, 102, 104, and the remaining ones are not arranged. Here, "not arranged" refers to a case where the gear motor 10 does not include the first and second rotation detectors 28, 30 and the torque detector 32 that are not arranged. For example, this means that the gear motor 10 does not include the first and second rotation detectors 28, 30, and the torque detector 32 is arranged in the third detector arrangement section 104. Furthermore, the gear motor 10 may operate when none of the first rotation detector 28, the second rotation detector 30, and the torque detector 32 are arranged. In this case, the gear motor 10 is driven by so-called sensorless control.
[0042] Assume a first condition that the first rotation detector 28 is arranged in the first detector arrangement section 100, a second condition that the second rotation detector 30 is arranged in the second detector arrangement section 102, and a third condition that the torque detector 32 is arranged in the third detector arrangement section 104. In this case, the gear motor 10 can be considered to be operable both when all of the first to third conditions are met and when only some of the conditions are met (when some of the conditions are not met).
[0043] Furthermore, the gear motor 10 can operate both when the brake 34 is disposed in the brake disposing portion 106 and when the brake 34 is not disposed. When the brake 34 is not disposed, this refers to the case where the gear motor 10 does not include the brake 34.
[0044] Please refer to Figures 1 and 2. Figures 2(a) to 2(d) are schematic diagrams of gear motors 10 of the first embodiment and first to third modified embodiments. Figure 2(b) shows the gear motor 10 of Figure 2(a) from which the torque detector 32 has been omitted. Figure 2(c) shows the gear motor 10 of Figure 2(a) from which the second rotation detector 30 and the detection shaft 24 have been omitted. Figure 2(d) shows the gear motor 10 of Figure 2(a) from which the brake 34 has been omitted. All of the gear motors 10 of Figures 2(b) to 2(d) have the same configuration as the gear motor 10 of Figure 2(a) except for the omitted components.
[0045] FIG. 2(a) shows a case where the detectors 28, 30, 32 and the brake 34 are arranged in the corresponding arrangements 100, 102, 104, 106. FIG. 2(b) shows a case where the first and second rotation detectors 28, 30 and the brake 34 are arranged in the corresponding arrangements 100, 102, 106, and the torque detector 32 is not arranged. FIG. 2(c) shows a case where the first rotation detector 28, the torque detector 32 and the brake 34 are arranged in the corresponding arrangements 100, 104, 106, and the second rotation detector 30 is not arranged. FIG. 2(d) shows a case where the detectors 28, 30, 32 are arranged in the corresponding arrangements 100, 102, 104, and the brake 34 is not arranged. The above means that the gear motor 10 is operable in all of these cases.
[0046] To satisfy the condition "when not arranged," the component itself including the arrangement portions 100, 102, 104, and 106 where the mentioned object should be arranged may be omitted. For example, to satisfy the condition "when the second rotation detector 30 is not arranged," the detection shaft 24 including the second shaft-side portion 102a of the second detector arrangement portion 102 may be omitted (see FIG. 2(c)). In this case, the sensor substrate 72 including the second opposing portion 102b of the second detector arrangement portion 102 may or may not be omitted. The same applies to the first rotation detector 28 and the torque detector 32.
[0047] The fact that the gear motor 10 is operable when the first rotation detector 28 is disposed in the first detector mounting portion 100 means that the motor 16 can be controlled by the control unit 68 using the detection signal of the first rotation detector 28. In this case, for example, the motor 16 may be driven so that the rotational speed and rotational position of the shaft 31 determined based on the detection signal of the first rotation detector 28 satisfy target conditions.
[0048] The gear motor 10 being operable when the second rotation detector 30 is disposed in the second detector mounting portion 102 means that the motor 16 can be controlled by the control unit 68 using the detection signal of the second rotation detector 30. In this case, for example, the motor 16 may be driven so that the rotational speed and rotational position of the detection shaft 24 (output member 48) determined based on the detection signal of the second rotation detector 30 satisfy target conditions.
[0049] The gear motor 10 being operable when the torque detector 32 is disposed in the third detector arrangement portion 104 means that the motor 16 can be controlled by the control portion 68 using the detection signal of the torque detector 32. In this case, for example, the motor 16 may be stopped based on the torque detected by the torque detector 32. Alternatively, the motor 16 may be driven so that the torque detected by the torque detector 32 becomes a target torque.
[0050] The fact that the gear motor 10 is operable when the torque detector 32 or the first or second rotation detector 28, 30 is not installed means that the motor 16 can be controlled by the control unit 68 without using the object that is not installed (e.g., the torque detector 32).
[0051] In this embodiment, "not disposing the first rotation detector 28" means that the first detection target member 28A is not disposed in the first shaft-side portion 100a of the first detector arrangement portion 100, and the first sensor 28B is not disposed in the first opposing portion 100b thereof. In this embodiment, "not disposing the second rotation detector 30" means that the second detection target member 30A is not disposed in the second shaft-side portion 102a of the second detector arrangement portion 102, and the second sensor 30B is not disposed in the second opposing portion 102b thereof. In this embodiment, "not disposing the torque detector 32" means that the torque detector 32 is not disposed in the third detector arrangement portion 104.
[0052] Being operable when the brake 34 is provided means that the shaft body 31 can be braked by the brake 34 under the control of the control unit 68. Being operable when the brake 34 is not provided means that the motor 16 can be controlled by the control unit 68 without using the brake 34. In this embodiment, "when the brake 34 is not provided" means that the brake main body 82 is not provided in the housing side portion 106a of the brake arrangement portion 106, and the rotating member 78 is not provided in the third shaft side portion 106b.
[0053] So far, we have described an example in which some combinations obtained by selecting one of the detectors 28, 30, 32 and the brake 34 are actually targeted for omission. However, the present invention is not limited to this, and the combination of elements to be actually targeted for omission may be any combination obtained by selecting one or more of these. Here, "multiple" may mean any number of two, three, or four.
[0054] The gear motor 10 described above can operate whether the detectors 28, 30, and 32 are arranged in all of the corresponding arrangement portions 100, 102, and 104, or whether only some of them are arranged. Therefore, the main elements of the gear motor 10 (motor 16, rotor shaft 18, reducer 20, housing 22, etc.) can be shared between a gear motor 10 that has all of the first and second rotation detectors 30 and torque detector 32 and a gear motor 10 that does not have some of them. In other words, the main elements can be shared between multiple types of gear motors 10. This allows for a reduction in manufacturing costs when dealing with multiple types of gear motors 10. In addition, it also allows for a reduction in design costs.
[0055] The gear motor 10 can operate with or without the brake 34. Therefore, the main elements of the gear motor 10 (motor 16, rotor shaft 18, reducer 20, housing 22, etc.) can be shared between gear motors 10 with and without the brake 34. This allows for further reductions in manufacturing and design costs when dealing with multiple types of gear motors 10.
[0056] The control unit 68 may be configured to execute plug-and-play, which automatically sets up the detectors 28, 30, 32 and the brake 34 so that they are ready for use when they are electrically connected. This allows even a user without specialized knowledge to easily incorporate the detectors 28, 30, 32 and the brake 34 into the gear motor 10.
[0057] Next, other features of the gear motor 10 will be described. Refer to Fig. 1. The gear motor 10 includes a plurality of external bearings 110, 112, 114 arranged on the outer periphery of the shaft body 31. The plurality of external bearings 110, 112, 114 include a first external bearing 110 arranged between the gear (external gear 50) driven by the gear drive section 40a of the input shaft 40 and the gear drive section 40a, a second external bearing 112 arranged on the anti-load side relative to the first external bearing 110, and a third external bearing 114 arranged on the load side relative to the first external bearing 110.
[0058] The first external bearing 110 of this embodiment is a so-called vibrator bearing. The first external bearing 110 is a rolling bearing such as a roller bearing. Although not shown, the first external bearing 110 includes a plurality of rolling elements and a retainer that holds the plurality of rolling elements.
[0059] The second external bearing 112 is disposed between the inner flange portion 64 of the housing 22 and the shaft body 31. The third external bearing 114 is disposed between the fitting protrusion 46 of the carrier 44 and the shaft body 31. The second and third external bearings 112, 114 are rolling bearings such as ball bearings.
[0060] The rotor shaft 18 and the input shaft 40 are integrally formed from the same material. The shaft body 31 consisting of the rotor shaft 18 and the input shaft 40 is formed from part of a single member. If the rotor shaft 18 and the input shaft 40 were formed separately, it would be necessary to assemble the shaft body 31. In contrast, according to this embodiment, assembly of the shaft body 31 is not necessary. Therefore, it is possible to prevent positional variations between the rotor shaft 18 and the input shaft 40 that may result from assembling the shaft body 31. In addition, since the number of parts can be reduced compared to when the rotor shaft 18 and the input shaft 40 are formed separately, it is possible to facilitate handling, reduce manufacturing costs, and improve reliability.
[0061] Referring to Figure 3, the shaft body 31 includes a part of the brake arrangement portion 106 described above (the third shaft side portion 106b described above), as well as a plurality of external bearing arrangement portions 120, 122, 124 in which the external bearings 110, 112, 114 are arranged, and a rotor arrangement portion 126 in which the rotor 38 is arranged.
[0062] The rotor mounting portion 126 is provided on the rotor shaft 18 of the shaft body 31. The rotor 38 is fixed to the rotor mounting portion 126 using adhesive, fitting, etc. A recessed portion 126a is formed in the rotor mounting portion 126 to reduce the weight of the shaft body 31.
[0063] The plurality of external bearing arrangements 120, 122, 124 correspond to the plurality of external bearings 110, 112, 114, respectively, and the corresponding external bearings 110, 112, 114 are arranged on the plurality of external bearing arrangements 120, 122, 124. The external bearing arrangements 120, 122, 124 include a first external bearing arrangement 120 corresponding to the first external bearing 110, a second external bearing arrangement 122 corresponding to the second external bearing 112, and a third external bearing arrangement 124 corresponding to the third external bearing 114.
[0064] The first external bearing arrangement portion 120 is provided on the gear drive portion 40a of the input shaft 40. In this embodiment, the first external bearing arrangement portion 120 has an elliptical shape like the gear drive portion 40a, and the second and third external bearing arrangement portions 122, 124 have circular shapes. The inner ring of the second external bearing 112 is arranged in the second external bearing arrangement portion 122. The inner ring of the second external bearing 112 is fixed to the second external bearing arrangement portion 122 by using a fitting involving press fitting or the like. The outer ring of the second external bearing 112 is arranged on the inner periphery of the inner flange portion 64 of the motor housing 60 (see FIG. 1). The inner ring of the third external bearing 114 is arranged in the third external bearing arrangement portion 124. The inner ring of the third external bearing 114 is fixed to the third external bearing arrangement portion 124 by using a fitting involving press fitting or the like.
[0065] On the outer periphery of the shaft body 31, in order from the anti-load side (right side in Figure 3) to the load side (left side in Figure 3), there are provided a rotor arrangement portion 126, a third shaft side portion 106b of the brake arrangement portion 106, a second external bearing arrangement portion 122, a first external bearing arrangement portion 120, and a third external bearing arrangement portion 124.
[0066] The maximum outer diameter of the first external bearing arrangement portion 120 is R120, the maximum outer diameter of the second external bearing arrangement portion 122 is R122, and the maximum outer diameter of the third external bearing arrangement portion 124 is R124. In addition, the maximum outer diameter of the rotor arrangement portion 126 is R126, and the maximum outer diameter of the third shaft side portion 106b of the brake arrangement portion 106 is R106. The maximum outer diameter here refers to the radius of a circumscribing circle that circumscribes the referenced location and is concentric with the rotation center line CL of the shaft body 31.
[0067] With respect to each of the multiple external bearing arrangement portions 120, 122, 124, the maximum outer diameters R120, R122, R124 of the external bearing arrangement portions 120, 122, 124 are the largest in the range from the external bearing arrangement portion 120, 122, 124 to the load-side end 31a of the shaft 31. The maximum outer diameter R120 of the first external bearing arrangement portion 120 is the largest in the range from the first external bearing arrangement portion 120 to the load-side end 31a. The maximum outer diameters R122, 124 of the other external bearing arrangement portions 122, 124 are similar. From the anti-load side to the load side, the maximum outer diameter R124 decreases in the following order: the maximum outer diameter R122 of the second external bearing arrangement portion 122, the maximum outer diameter R120 of the first external bearing arrangement portion 120, and the third external bearing arrangement portion 124.
[0068] As a result, the multiple external bearings 110, 112, 114 can be disposed on the outer periphery of the shaft body 31 by moving them relative to the shaft body 31 from the load-side end 31a of the shaft body 31 toward the anti-load side. Therefore, when assembling the multiple external bearings 110, 112, 114 into the shaft body 31, the direction of their relative movement can be made common, resulting in good workability.
[0069] The maximum outer diameter R126 of the rotor mounting portion 126 is the largest outer diameter in the range from the rotor mounting portion 126 to the load side end 31 a of the shaft 31. This makes it possible to position the rotor 38, in addition to the multiple external bearings 110, 112, and 114, on the outer periphery of the shaft 31 by relatively moving it from the load side end 31 a of the shaft 31 toward the anti-load side.
[0070] The maximum outer diameter R106 of the third shaft side portion 106b of the brake arrangement portion 106 is the largest outer diameter in the range from the third shaft side portion 106b to the load side end 31a of the shaft 31. As a result, the rotating member 78 of the brake 34 can also be arranged on the outer periphery of the shaft 31 by moving it relatively from the load side end 31a of the shaft 31 toward the anti-load side.
[0071] See Figure 4. The motor housing 60 is obtained by processing a base housing 130 as an intermediate product. The base housing 130 as an intermediate product is an integrally molded product (cast molding) like the motor housing 60. Like the motor housing 60, the base housing 130 is cylindrical overall and includes a stator mounting portion 62, an inner flange portion 64, and a housing-side portion 106a of the brake mounting portion 106.
[0072] The base housing 130 includes a cylindrical length adjustment portion 132 that extends from the anti-load side end of the base housing 130 to a portion of the load side. The length adjustment portion 132 is provided in the base housing 130 in an axial range that includes the stator mounting portion 62 where the stator 36 is to be mounted. The motor housing 60 as a finished product is obtained by cutting an axially intermediate portion of the length adjustment portion 132 of the base housing 130. At this time, the anti-load side portion of the base housing 130 is excluded from the cut position of the length adjustment portion 132. The housing length of the motor housing 60 can be adjusted by adjusting the cut position of the length adjustment portion 132 of the base housing 130. Here, "length" refers to the axial dimension. After cutting the length adjustment portion 132 of the base housing 130, it is desirable to perform finish machining on the cut portion.
[0073] See Figures 5(a) to 5(c). The base housing 130 is shared by multiple types of motors 16A to 16C with different motor lengths. Here, the multiple types of motors are distinguished by adding A, B, or C to the end of the reference numerals. The multiple types of motors 16A to 16C include, for example, a first motor 16A (see Figure 5(a)) with a first motor length L16A, which is the maximum length. In addition, the multiple types of motors 16A to 16C include a second motor 16B (see Figure 5(b)) with a second motor length L16B that is shorter than the first motor length L16A, and a third motor 16C (see Figure 5(c)) with a third motor length L16C that is shorter than the second motor length L16B.
[0074] 5(a), the base housing 130 has a first housing length L130A corresponding to the first motor 16A having a predetermined maximum length (first motor length 16A) among the multiple types of motors 16A to 16C. When used with the motor 16A having the first motor length L16A, the base housing 130 itself constitutes the motor housing 60.
[0075] As shown in Figure 5(b), when used with a motor 16B having a second motor length L16B, the motor housing 60 is constructed by cutting the length adjustment portion 132 of the base housing 130 so that the second housing length L130B corresponds to the second motor length L16B. As shown in Figure 5(c), when used with a motor 16C having a third motor length L16C, the motor housing 60 is constructed by cutting the length adjustment portion 132 of the base housing 130 so that the third housing length L130C corresponds to the third motor length L16C. The figure shows the cutting position Cp of the base housing 130.
[0076] Thus, when the motor housing 60 is used for the second and third motors 16B and 16C, the base housing 130 is cut to housing lengths L130B and L130C corresponding to the motor lengths L16B and L16C of the motors 16B and 16C being used. In this case, the housing lengths L16B and L16C of the motor housing 60 are shortened as the motor lengths L16B and L16C of the motors 16B and 16C being used become shorter.
[0077] This allows the base housing 130 to be shared to obtain the motor housings 60 corresponding to the multiple types of motors 16A to 16C. Therefore, compared to when the motor housings 60 corresponding to the multiple types of motors 16A to 16C are constructed as one-piece molded parts dedicated to each type of motor 16A to 16C, the number of parts that must be managed during the manufacturing process of the gear motor 10 can be reduced, and ultimately manufacturing costs can be reduced.
[0078] Furthermore, by adjusting the housing length according to the motor length of the motors 16A to 16C being used, it is possible to efficiently increase the torque per unit weight. This can be achieved by shortening the housing length accordingly as the motor length becomes shorter (the output of the motor 16 becomes smaller).
[0079] Referring to Figure 6, the gear motor 10 includes an internal bearing 140 that is disposed inside the rotor shaft 18, between the rotor shaft 18 and the detection shaft 24. The internal bearing 140 is a rolling bearing such as a ball bearing. The internal bearing 140 includes an inner ring 142 that is fixed to the detection shaft 24, an outer ring 144 that is fixed to the rotor shaft 18, and rolling elements 146 that roll between the inner ring 142 and the outer ring 144. The anti-load side portion of the detection shaft 24 is supported on the inner periphery of the rotor shaft 18 via the internal bearing 140.
[0080] This prevents runout of the anti-load side end 24a of the detection shaft 24, improving the detection accuracy of the second rotation detector 30. In addition, the length (axial dimension) of the detection shaft 24 can be made smaller than when the detection shaft 24 is supported by the driver unit 26 via a bearing. As a result, the detection shaft 24 is lighter in weight and can be more easily processed.
[0081] The rotor shaft 18 includes a first shaft side portion 100a of the first detector arrangement portion 100, a first internal bearing arrangement portion 150, and a first stepped portion 152, which are provided in this order from the anti-load side toward the load side on the inner periphery of the rotor shaft 18. The first stepped portion 152 faces the anti-load side of the rotor shaft 18.
[0082] The first shaft side portion 100a is provided at the anti-load side end of the rotor shaft 18. The first detection member 28A of the first rotation detector 28 is disposed in the first shaft side portion 100a. The first shaft side portion 100a is continuous in an annular shape at the anti-load side end 18a of the rotor shaft 18. In this embodiment, the first shaft side portion 100a is configured with a stepped recess whose inner diameter increases toward the anti-load side. The first detection member 28A is fixed to a stepped portion 100c facing the anti-load side of the first shaft side portion 100a using an adhesive (not shown).
[0083] The outer ring 144 of the inner bearing 140 is disposed in the first inner bearing arrangement 150. The outer ring 144 is fixed to the first inner bearing arrangement 150 by a fit such as an interference fit or a transition fit. The inner diameter R150 of the first inner bearing arrangement 150 is larger than the inner diameter R154 of a portion 154 of the rotor shaft 18 that is located on the load side of the rotor shaft 18 relative to the first inner bearing arrangement 150. Here, the portion 154 of the rotor shaft 18 refers to, for example, a position that radially overlaps with the load-side end 16a of the motor 16. This allows for a larger space to accommodate the inner bearing 140 compared to when the inner diameter R150 of the first inner bearing arrangement 150 is matched to the inner diameter R154 of the rotor shaft 18. Consequently, a larger inner bearing 140 can be used to ensure durability.
[0084] The detection shaft 24 includes a second shaft side portion 102a of the second detector arrangement portion 102, a second step portion 156, and a second internal bearing arrangement portion 158, which are arranged in this order on the outer periphery of the detection shaft 24 from the anti-load side toward the load side.
[0085] The second shaft side portion 102a is provided at the anti-load side end of the detection shaft 24. The second detection member 30A of the second rotation detector 30 is disposed in the second shaft side portion 102a. The second shaft side portion 102a is continuous in an annular shape at the anti-load side end 24a of the detection shaft 24. In this embodiment, the second shaft side portion 102a is configured with a stepped recess whose outer diameter decreases toward the anti-load side. The second detection member 30A is fixed to a stepped portion 102c facing the anti-load side of the second shaft side portion 102a using an adhesive (not shown).
[0086] The second step 156 is provided on the load side of a protrusion 160 that protrudes radially outward and is provided on the outer periphery of the detection shaft 24. The second step 156 abuts against the inner ring 142 of the internal bearing 140 from the anti-load side, thereby restricting the axial position of the inner ring 142.
[0087] The inner ring 142 of the inner bearing 140 is disposed in the second inner bearing arrangement portion 158. The inner ring 142 is fixed to the second inner bearing arrangement portion 158 by a fit such as an interference fit or an intermediate fit.
[0088] See Figures 1 and 6. The gear motor 10 includes an elastic member 162 that is disposed at a position sandwiched between the rotor shaft 18 and the internal bearing 140 in the axial direction X. In this embodiment, the elastic member 162 is an annular leaf spring. There are no particular limitations on the elastic member 162, and it may be, for example, a rubber body. The elastic member 162 is sandwiched together with the internal bearing 140 between the first step portion 152 of the rotor shaft 18 and the second step portion 156 of the detection shaft 24, and is thereby provided in a state of being compressed and deformed in the axial direction X.
[0089] The elastic member 162 presses the outer ring 144 of the internal bearing 140 toward the detection shaft 24 in the axial direction X by an elastic restoring force resulting from its own elastic deformation. As a result, the elastic member 162 applies a preload in the axial direction X to the internal bearing 140 so that the axial internal clearance of the internal bearing 140 is zero or a negative magnitude. When no preload is applied, this axial internal clearance is provided between the inner ring 142 and the outer ring 144 and the rolling elements 146, respectively. When the axial internal clearance is positive, relative movement (backlash) of the rolling elements 146 in the axial direction X with respect to the inner ring 142 and the outer ring 144 is permitted. On the other hand, when the axial internal clearance is zero or a negative state, relative movement (backlash) of the rolling elements 146 in the axial direction X with respect to the inner ring 142 and the outer ring 144 is restricted.
[0090] The elastic member 162 described above can suppress rattle of the rolling elements 146 and prevent noise caused by rattle. Furthermore, the elastic deformation of the elastic member 162 in the axial direction X can adjust the positions of the detection shaft 24 and the rotor shaft 18 in the axial direction X while the elastic member 162 applies preload to the internal bearing 140. In other words, the elastic member 162 can prevent noise while allowing the positions of the detection shaft 24 and the rotor shaft 18 in the axial direction X to be adjusted. To perform such a position adjustment, the detection shaft 24 can be fixed to the output member 48 while adjusting the axial position of the detection shaft 24 relative to the output member 48, as described above.
[0091] In this embodiment, the first detectable member 28A of the first rotation detector 28 is disposed on the rotor shaft 18, and the second detectable member 30A of the second rotation detector 30 is disposed on the detection shaft 24. Therefore, by adjusting the positions of the detection shaft 24 and the rotor shaft 18 in the axial direction X, the positions of the first detectable member 28A and the second detectable member 30A in the axial direction X can be aligned. This makes it easy to align the relative positions of the detectable members 28A, 30A with respect to the common sensor board 72 in the axial direction X, thereby improving the detection accuracy of the rotation detectors 28, 30.
[0092] Refer to Figure 7. Figure 7 is a side cross-sectional view of the gear motor 10 cut at a different circumferential position than Figure 1. The gear motor 10 is equipped with electronic components 170, 172 arranged on the load side of the motor 16. The electronic components 170, 172 of this embodiment include a first electronic component 170 which is the torque detector 32 and a second electronic component 172 which is the coil 90 which is a component of the brake 34. The first electronic component 170 is arranged in the reducer housing 47. The second electronic component 172 is arranged in the motor housing 60.
[0093] The gear motor 10 includes wiring 174, 176 that connects electronic components 170, 172 to the driver unit 26. Fig. 7 mainly shows the center lines of the wiring 174, 176. The wiring 174, 176 includes a first wiring 174 that connects the control board 70 of the driver unit 26 to the first electronic component 170, and a second wiring 176 that connects the control board 70 to the second electronic component 172. The wiring 174, 176 is connected to the control board 70 via a connector 178 provided on the control board 70.
[0094] The housing 22 has an outlet hole 180 for extracting the wiring 174, 176 from the interior of the housing 22 to the outside. The outlet hole 180 has an external opening 182 that opens to the outer periphery of the housing 22 and internal openings 184, 186 that open to the interior of the housing 22. The internal openings 184, 186 include a first internal opening 184 that opens to the reducer housing 47 and a second internal opening 186 that opens to the motor housing 60. The outlet hole 180 has a radial portion 180a that extends in the radial direction and an axial portion 180b that extends in the axial direction. The external opening 182 is provided at the outer peripheral end of the radial portion 180a. The inner peripheral portion of the radial portion 180a opens to the interior of the motor housing 60 and also opens to the axial portion 180b. The axial portion 180b penetrates the inner flange portion 64 of the motor housing 60 in the axial direction X. A grommet 190 for preventing leakage of the lubricant sealed in the internal space 188 of the reducer 20 is disposed in the axial portion 180b.
[0095] A portion of the wiring 174, 176 is routed outside the motor housing 60. More specifically, the wiring 174, 176 is routed outside the motor housing 60 from an outlet hole 180 on the load side of the motor 16. The first wiring 174 is routed from the outlet hole 180 through a first internal opening 184 and an external opening 182. The first wiring 174 of this embodiment is inserted through a grommet 190. The second wiring 176 is routed from the outlet hole 180 through a second internal opening 186 and an external opening 182. The first and second wirings 174, 176 are routed from the outlet hole 180 through a common external opening 182. The wiring 174, 176 are routed outside the motor housing 60 at a position where they radially overlap the motor 16. The wiring 174, 176 are connected to a connector 178 of the driver unit 26 on the anti-load side of the motor housing 60.
[0096] See Figures 7 and 8. The motor housing 60 has a wiring groove 192 provided on the outer periphery of the motor housing 60, extending from the load side to the anti-load side. The wiring groove 192 continues from the outer opening 182 of the lead-out hole 180 to the anti-load side end of the motor housing 60. In this embodiment, the wiring groove 192 has a plurality of wiring grooves 192 (three in this embodiment) arranged side by side in the circumferential direction. The number of wiring grooves 192 is not particularly limited, and may be one, two, or four or more.
[0097] The wires 174, 176 are arranged along the wire groove 192 outside the housing 22. This allows the wires 174, 176 to be arranged while being guided by the wire groove 192, facilitating the installation of the wires 174, 176. In addition, there is no need to attach dedicated elements such as guides for installing the wires 174, 176 to the housing 22, which allows the gear motor 10 to be made smaller and lighter.
[0098] Each of the multiple wires 174, 176 is disposed in a separate wire groove 192. The wires 174, 176 are disposed so as to fit within the wire groove 192 as viewed from the axial direction X. This means that the wires 174, 176 are disposed so as not to protrude radially outward from an entrance opening 192a provided on the entrance side of the wire groove 192 as viewed from the axial direction X. Note that in this embodiment, a driver mount 196, which will be described later, also has a wire groove 194 formed therein for disposing the wires 174, 176 therein.
[0099] The wires 174, 176 are routed outside the motor housing 60. This eliminates the need to secure extra wiring space between the motor housing 60 and the motor 16 for arranging the wires 174, 176. This in turn prevents the motor 16 from being downsized due to the need to secure extra wiring space.
[0100] See Figures 1, 9, 10, and 11. The board holder 74 of the driver unit 26 includes a plate-shaped base portion 74a disposed on the anti-load side of the control board 70, and first and second seats 74b and 74c protruding from the base portion 74a toward the load side. The control board 70 is seated on the first seat portion 74b and fixed thereto by a screw member. The sensor board 72 is seated on the second seat portion 74c and fixed thereto by a screw member. The board holder 74 includes a peripheral wall portion 74d provided radially outward from the control board 70.
[0101] The gear motor 10 includes a driver mount 196 for mounting the driver unit 26 to the motor housing 60. The driver mount 196 is cylindrical overall. The driver mount 196 includes an insertion portion 196a that is inserted into the load side from an anti-load side opening of the motor housing 60, an annular outer flange portion 196b that is provided on the anti-load side of the insertion portion 196a, and a thick portion 196c that protrudes radially outward from the insertion portion 196a.
[0102] The outer flange portion 196b protrudes radially outward from the outer periphery of the driver mount 196. The outer flange portion 196b abuts against the anti-load side end of the motor housing 60.
[0103] 9 and 10 . The thick-walled portion 196c has a radial dimension that is thicker than the insertion portion 196a. The thick-walled portion 196c protrudes radially outward beyond the insertion portion 196a and is disposed within a recess 198 formed in the motor housing 60. The peripheral wall portion 74d of the board holder 74 abuts against the driver mount 196 from the anti-load side and is connected to the driver mount 196 in the axial direction X by a screw member 200 that penetrates the board holder 74. The screw member 200 is screwed into an internally threaded hole 196d formed in the driver mount 196 at a position that radially overlaps with the thick-walled portion 196c.
[0104] 11, the motor housing 60 has a housing-side fixing hole 202 that passes radially through the motor housing 60. The driver mount 196 has a mount-side fixing hole 204 that passes radially through the insertion portion 196a of the driver mount 196.
[0105] The driver mount 196 is connected to the motor housing 60 by a plurality of rivets 210. Only a single rivet 210 is shown in the figure. The rivets 210 connect the motor housing 60 and the driver mount 196 in the radial direction. The rivets 210 connect the motor housing 60 and the driver mount 196 at points where they overlap in the radial direction. The multiple rivets 210 are provided at positions spaced apart in the circumferential direction. The rivets 210 have a head 210a that is disposed on the outside of the motor housing 60 and a shank 210b that is inserted into the fixing holes 202, 204 of the motor housing 60 and the driver mount 196.
[0106] The head 210a of the rivet 210 is fitted into a counterbore 60b provided on the outer periphery of the motor housing 60. The rivet 210 connects the motor housing 60 and the driver mount 196 by providing a crimped portion 210c on a part of the rivet 210. This part of the rivet 210 is the tip end portion of the shank 210b. The crimped portion 210c of the rivet 210 abuts against the driver mount 196, thereby preventing it from being pulled out of the fixing holes 202, 204. The crimped portion 210c of the rivet 210 is in close contact with the inner periphery of the mount-side fixing hole 204, preventing the driver mount 196 from being misaligned in the radial direction relative to the rivet 210.
[0107] The rivet 210 of this embodiment is a blind rivet, and has a hollow hole 210d that penetrates a shank 210b of the rivet 210. A mandrel 212 is inserted into the hollow hole 210d from the radially inner side toward the outer side, and the mandrel 212 is then pulled out radially outward, thereby providing a crimped portion 210c in the rivet 210. At this time, a necked portion 212b of the mandrel 212 breaks, leaving a head portion 212a of the mandrel 212 remaining in the rivet 210.
[0108] Driver mount 196 is connected to housing 22 with rivets 210. Therefore, compared to when screws are used, there is no need to ensure clearance between the shanks of the screws and fixing holes 202, 204. As a result, it becomes possible to connect driver mount 196 and housing 22 while preventing radial misalignment. In particular, when sensors 28B, 30B of rotation detectors 28, 30 are incorporated into driver mount 196, preventing radial misalignment between driver mount 196 and housing 22 can improve the detection accuracy of rotation detectors 28, 30.
[0109] The rivet 210 connects the motor housing 60 and the driver mount 196 in the radial direction. Therefore, the radial thickness of the housing 22 can be made thinner than when the motor housing 60 and the driver mount 196 are connected in the axial direction X by the rivet 210. This in turn allows the outer diameter of the housing 22 to be made smaller. In addition, compared to when a screw is used, the mount-side fixing hole 204 does not need to be provided with a female thread, so the radial thickness of the driver mount 196 can be made thinner.
[0110] Next, another use of the gear motor 10 of the first embodiment will be described. Refer to Fig. 12. The gear motor 10 is equipped with a heat sink 220 for radiating heat transferred from the motor housing 60 to the outside. Use of the heat sink 220 can promote cooling of the motor housing 60. The heat sink 220 is equipped with a peripheral wall portion 220a that covers the motor housing 60, and a plurality of fin portions 220b that protrude radially outward from the peripheral wall portion 220a.
[0111] The peripheral wall portion 220a is fitted to the outside of the motor housing 60, for example, so as to be slidable in the axial direction X on the motor housing 60 and inseparable in the radial direction. To achieve this, the peripheral wall portion 220a has an arc shape that continues over a circumferential range that is longer than half the circumference of the motor housing 60. Alternatively, to achieve this, the peripheral wall portion 220a may have an annular shape that continues over a range that covers the entire circumference of the motor housing 60.
[0112] The heat dissipator 220 may be equipped with a cooling mechanism for cooling the heat dissipator 220. The cooling mechanism may be, for example, a fan that generates an airflow that hits the heat dissipator 220. Alternatively, the cooling mechanism may be, for example, a combination of a cooling medium passage such as a water jacket provided inside the heat dissipator 220 and a pump that circulates a cooling medium such as cooling water through the cooling medium passage.
[0113] (Second embodiment) See Figures 13 and 14. An industrial robot 250 using the gear motor 10 includes the gear motor 10 incorporated into a joint of the industrial robot 250, as well as the first and second mating members 12, 14 connected via the gear motor 10. The gear motor 10 has the same configuration as the first embodiment except for the housing 22, which will be described later, and therefore will not be described here.
[0114] The first mating member 12 includes a main body member 252 disposed on the anti-load side of the gear motor 10, and a plurality of (two in this embodiment) cover members 254 fixed to the main body member 252 with bolts or the like. The plurality of cover members 254 cover the entire housing 22 from the radially outer side. The entire plurality of cover members 254 has a cylindrical cross section in a cross section perpendicular to the axial direction X. Each of the plurality of cover members 254 has a cross-sectional shape obtained by dividing the cylindrical cross section into a plurality of (two in this embodiment) sections. Adjacent cover members 254 have butt ends 254a provided at the circumferential ends of the respective cover members 254 and butting against each other.
[0115] The cover member 254 includes a protrusion 256 provided on the inner periphery of the cover member 254. The protrusion 256 protrudes radially inward from the inner periphery of the cover member 254 and is continuous in the circumferential direction.
[0116] The gear motor 10 includes fasteners 258 that fasten the butt ends 254a of adjacent cover members 254. A separate fastener 258 is used for each of the butt ends 254a on both circumferential sides of the cover member 254. The fasteners 258 are individually provided at positions spaced apart in the axial direction X. The fasteners 258 include a bolt 258a and a nut 258b. The bolt 258a is inserted into an insertion hole 259 provided in the cover member 254. The fasteners 258 apply a fastening force in a fastening direction Da that moves the butt ends 254a of the adjacent cover members 254 closer to each other as viewed from the axial direction X.
[0117] The housing 22 includes a groove 260 provided on the outer periphery of the housing 22. In this embodiment, the groove 260 is provided on the outer periphery of the motor housing 60. The groove 260 is recessed radially inward on the outer periphery of the housing 22 and is continuous in an annular shape in the circumferential direction. A protrusion 256 of the cover member 254 is disposed inside the groove 260.
[0118] The protrusions 256 and the grooves 260 each have a shape in which the axial dimension decreases toward the radially inner side. In this embodiment, the shapes that satisfy this condition are trapezoidal for the protrusions 256 and V-shaped for the grooves 260. By satisfying this condition, the protrusions 256, which become part of the cover member 254, can be fitted into the grooves 260 of the housing 22 in the fastening direction Da by fastening with the fasteners 258.
[0119] This increases the static friction force between the protrusion 256 of the cover member 254 and the groove 260 of the housing 22. This static friction force in turn restricts the relative rotation of the housing 22 with respect to the cover member 254, allowing the housing 22 to be integrated with the first mating member 12. This has the advantage of not requiring bolt holes in the housing 22.
[0120] The housing 22 has outer smooth surfaces 262 provided on the outer periphery of the housing 22 and provided on both axial sides of the groove portion 260. The cover member 254 has inner smooth surfaces 264 provided on the inner periphery of the cover member 254 and provided on both axial sides of the protrusion portion 256. The smooth surfaces 262, 264 are smooth, continuous surfaces without forming any irregularities in the axial direction X. The inner smooth surface 264 is in surface contact with the outer smooth surface 262.
[0121] Consider a case where an inner smooth surface 264 is provided where the protrusion 256 of the cover member 254 is located, and an outer smooth surface 262 is provided where the groove 260 of the housing 22 is located. Compared to this case, by bringing the protrusion 256 of the cover member 254 into contact with the groove 260 of the housing 22, it is easier to increase the contact area between the cover member 254 and the housing 22. As a result, heat generated inside the gear motor 10 can be transferred to the housing 22 and then effectively dissipated by the cover member 254, which is exposed to the external space.
[0122] Other variations of each component are described.
[0123] There is no particular limitation on the use of the gear motor 10. For example, the gear motor 10 may be used in an automatic guided vehicle such as an AGV, in addition to an industrial robot.
[0124] There are no particular limitations on the specific example of the speed reduction mechanism 42. In addition to the flexible mesh gear mechanism, the speed reduction mechanism 42 may be, for example, an eccentric oscillating gear mechanism, a planetary gear mechanism, a perpendicular shaft gear mechanism, a parallel shaft gear mechanism, or the like. In the case of a flexible mesh speed reduction mechanism, there are no particular limitations on the specific example. In addition to a cylindrical type, for example, a cup type or a top hat type may be used.
[0125] The output member 48 of the reducer 20 may be the reducer housing 47 instead of the carrier 44. In this case, the output member 48 outputs the rotation extracted from the reduction mechanism 42 to the first mating member 12 integrated with the reducer housing 47.
[0126] The driver unit 26 may be configured with only the control board 70. The driver unit 26 may be attached directly to the motor housing 60 without using the driver mount 196. The gear motor 10 may not have the driver unit 26. In this case, the control unit 68 of the driver unit 26 may be arranged outside the gear motor 10 as a separate unit.
[0127] The sensors 28B, 30B of the rotation detectors 28, 30 may be arranged in the motor housing 60 instead of the driver unit 26. This means that the opposing portions 100b, 102b of the detector arrangement portions 100, 102 may be provided on the motor housing 60.
[0128] The brake 34 is not limited to a disc brake, and may be, for example, a drum brake. Although the example in which the rotating member 78 is part of the brake 34 has been described, the rotating member 78 may be the shaft 31 itself. In this case, the movable friction member 84 may be pressed against the outer periphery of the shaft 31 that serves as the rotating member 78, thereby braking the rotating member 78 by friction.
[0129] There is no particular limitation on the position where the brake 34 is disposed. For example, the brake 34 may be disposed on the anti-load side of the motor 16.
[0130] Although the example in which the first detector arrangement portion 100 is provided on the shaft body 31 has been described, the present invention is not limited to this. For example, the first detector arrangement portion 100 may be provided on the stator 36. This assumes, for example, that the first rotation detector 28 is a Hall element that detects the rotation of the rotor shaft 18 by detecting the permanent magnet of the rotor 38.
[0131] The gear motor 10 may not include the brake arrangement 106.
[0132] The rotor shaft 18 and the input shaft 40 may be configured as separate bodies.
[0133] A portion of the brake arrangement portion 106 (the third shaft-side portion 106b) does not have to be integrally provided with the rotor shaft 18. This is based on the assumption that, for example, the rotating member 78 braked by the brake mechanism 80 is the rotor shaft 18 itself, as described above. Alternatively, a portion of the brake arrangement portion 106 (the third shaft-side portion 106b) may be integrally provided with the input shaft 40 instead of the rotor shaft 18.
[0134] The motor housing 60 may be configured as a dedicated integrally molded product corresponding to each of the plurality of types of motors 16A to 16C.
[0135] The detection shaft 24 may be supported via a bearing by either the input shaft 40 or the driver unit 26, instead of the rotor shaft 18. Alternatively, the detection shaft 24 may be cantilevered by the output member 48 alone.
[0136] The gear motor 10 does not necessarily have to include the elastic member 162 for applying an axial preload to the internal bearing 140. In the example described above, the elastic member 162 is disposed at a position sandwiched in the axial direction X between the first step portion 152 of the rotor shaft 18 and the internal bearing 140. Alternatively, the elastic member 162 may be disposed at a position sandwiched in the axial direction X between the second step portion 156 of the detection shaft 24 and the internal bearing 140. In other words, it is sufficient that the elastic member 162 is disposed at a position sandwiched in the axial direction X between either the detection shaft 24 or the rotor shaft 18 and the internal bearing 140. In either case, it is sufficient that the elastic member 162 applies a preload in the axial direction X to the internal bearing 140.
[0137] There is no particular limitation on the number of electronic components arranged on the load side of the motor 16. For example, the electronic components may be only either the first electronic component 170 or the second electronic component 172. Furthermore, there is no particular limitation on the specific examples of the electronic components.
[0138] The wiring 174, 176 may be routed between the motor housing 60 and the motor 16 without passing outside the motor housing 60. If the wiring 174, 176 is routed outside the motor housing 60, the motor housing 60 does not need to be provided with the wiring groove 192.
[0139] When the outer periphery of the motor housing 60 is exposed to the external space, a cover material 270 (see FIG. 8 ) that covers the wires 174, 176 together with the wire groove 192 may be attached to the motor housing 60. The cover material 270 is, for example, a metal foil tape made of aluminum or the like. Alternatively, when a heat sink 220 is attached to the motor housing 60, the heat sink 220 may cover the wires 174, 176 together with the wire groove 192. Alternatively, the first mating member 12 may cover the wires 174, 176 together with the wire groove 192.
[0140] The means for connecting the driver mount 196 to the motor housing 60 is not particularly limited. This connecting means may be, for example, a screw. The rivet 210 may connect the housing 22 and the driver mount 196 in the axial direction. Furthermore, when the motor housing 60 and the driver mount 196 are connected radially by the rivet 210, the head 210a of the rivet 210 may be positioned radially inward relative to the motor housing 60.
[0141] The groove 260 of the housing 22 of the second embodiment may be provided in the reducer housing 47. The number of cover members 254 that cover the housing 22 is not particularly limited. For example, there may be three or more cover members 254.
[0142] The above-described embodiments and modified embodiments are merely examples. The abstract technical ideas should not be interpreted as being limited to the content of the embodiments and modified embodiments. Many design modifications are possible in the content of the embodiments and modified embodiments, such as changing, adding, or deleting components. In the above-described embodiments, the content that allows such design modifications is emphasized by adding the notation "embodiment." However, design modifications are also permitted even in content that does not have such notation. Hatching on cross sections in the drawings does not limit the material of the hatched object. [Explanation of symbols]
[0143] 10...gear motor, 16...motor, 18...rotor shaft, 20...reduction gear, 20, 22...housing, 24...detection shaft, 26...driver unit, 28...first rotation detector, 30...second rotation detector, 31...shaft, 32...torque detector, 34...brake, 38...rotor, 40...input shaft, 48...output member, 60...motor housing, 100...first detector arrangement portion, 102...second detector arrangement portion, 104...third detector arrangement portion, 106...brake arrangement portion, 110, 112, 114...external bearing, 120, 122, 124...external bearing arrangement portion, 130...base housing, 140...internal bearing, 162...elastic member, 170, 172...electronic components, 174, 176...wiring, 192...wiring groove, 196...driver mount, 210...rivet.
Claims
1. A gear motor including a motor and a reducer, a motor having a rotor shaft, and a reducer having an output member; a detection shaft that passes through the input shaft and the rotor shaft of the reducer and rotates integrally with the output member of the reducer, The rotational speed control device is operable in both a first case in which a first rotation detector that detects rotation of the rotor shaft, a second rotation detector that detects rotation of the output member via the detection shaft, and a torque detector are arranged, and a second case in which the first rotation detector and the second rotation detector are arranged but a torque detector is not arranged, the detection axis is shared between the first case and the second case, the reducer includes a first internal gear whose relative rotation with respect to a reducer housing is restricted, and a second internal gear that is rotatable relative to the reducer housing, The torque detector is a gear motor attached to a side portion of the first internal gear in the axial direction.
2. Further comprising a control unit, The gear motor according to claim 1 , wherein the control unit controls the motor based on a detection signal from one of the first rotation detector, the second rotation detector, and a torque detector.
3. The rotor shaft and the input shaft of the reducer are integrally formed from the same material, a plurality of external bearings disposed on an outer periphery of a shaft body including the rotor shaft and the input shaft; the shaft body includes a plurality of external bearing arrangement portions that correspond to the plurality of external bearings, and that arrange the corresponding external bearings; 2. The gear motor according to claim 1, wherein the maximum outer diameter of each of the plurality of external bearing arrangement portions is the largest outer diameter in the range from the external bearing arrangement portion to the load side end of the shaft body.
4. a motor housing that houses the motor; 2. The gear motor according to claim 1, wherein the motor housing is formed by cutting a base housing to a housing length corresponding to the motor length of the motor to be used.
5. 2. The gear motor according to claim 1, wherein in the first and second cases where the second rotation detector is disposed, the detection shaft is supported on an inner periphery of the rotor shaft via an internal bearing.
6. 6. The gear motor according to claim 5, wherein in the first and second cases in which the second rotation detector is disposed, the second rotation detector is disposed at a position axially sandwiched between the internal bearing and either the detection shaft or the rotor shaft, and the elastic member applies an axial preload to the internal bearing.
7. a motor housing that accommodates the motor; an electronic component disposed on the load side of the motor; a driver unit disposed on the opposite side of the motor from the load side and having a control unit; wiring connecting the electronic component and the driver unit; The gear motor according to claim 1 , wherein the wiring is routed outside the motor housing.
8. the motor housing includes a wiring groove provided on an outer periphery of the motor housing and extending from a load side toward an anti-load side; The gear motor according to claim 7 , wherein the wiring is drawn to the outside of the motor housing on the load side of the motor and arranged along the wiring groove.
9. a motor housing that accommodates the motor; a driver unit disposed on the opposite side of the motor from the load side and having a control unit; a driver mount for attaching the driver unit to the motor housing, 2. The gear motor of claim 1, wherein the driver mount is connected to the motor housing by a rivet.
10. The gear motor of claim 9 , wherein the rivet radially connects the motor housing and the driver mount.
Citation Information
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