Eccentric oscillating gear device

Abstract

To provide a technique that can detect the rotation of rotary elements in an eccentric oscillation type gear device comprising a plurality of crankshafts.SOLUTION: An eccentric oscillation type gear device comprises an oscillation gear, a plurality of crankshafts 24A-24C arranged at positions offset in radial directions of the oscillation gear from a center of the oscillation gear, and crankshaft gears 26A-26C provided on at least one of the crankshafts 24A-24C, and to which rotation is inputted, and comprises a rotation detector 60 opposed to tooth parts 44 of the crankshaft gears 26A and 26B, and detecting the rotation of the crankshaft gears 26A and 26B.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an eccentric oscillating gear device. [Background technology]

[0002] Patent Document 1 discloses an eccentric oscillating gear device equipped with multiple crankshafts. This gear device includes an oscillating gear, multiple crankshafts disposed at positions offset from the center of the oscillating gear in the radial direction of the oscillating gear, and a crankshaft gear provided on at least one of the crankshafts and receiving rotation as an input. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-72842 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to control the operation of a gear device, it is desirable to be able to detect the rotation of a rotating element used in the gear device. However, no device has yet been proposed that incorporates a mechanism for detecting the rotation of a rotating element in an eccentric oscillating gear device equipped with multiple crankshafts.

[0005] An object of the present disclosure is to provide a technique that makes it possible to detect the rotation of a rotating element in an eccentric oscillating gear device that is equipped with multiple crankshafts. [Means for solving the problem]

[0006] The gear device disclosed herein is an eccentric oscillating type gear device comprising an oscillating gear, a plurality of crankshafts arranged at a position radially offset from the center of the oscillating gear, and a crankshaft gear provided on at least one of the crankshafts to which rotation is input, and further comprising a rotation detector that faces the teeth of the crankshaft gear and detects the rotation of the crankshaft gear. Effect of the Invention

[0007] According to the present disclosure, in an eccentric oscillating gear device having multiple crankshafts, it becomes possible to detect the rotation of the crankshaft gears. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a side cross-sectional view of the gear device of the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section taken along line AA in FIG. [Diagram 3] FIG. 3 is an enlarged view of a portion of FIG. [Figure 4] FIG. 2 is a block diagram of a gear motor according to an embodiment. [Diagram 5] 3 is a diagram showing a state in which the carrier has been rotated from the state shown in FIG. 2; FIG. [Figure 6] FIG. 4 is a view of a gear device according to a second embodiment, seen from the same perspective as FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described. The same components are given the same reference numerals, and duplicated explanations will be omitted. In each drawing, for the sake of convenience, components are omitted, enlarged, or reduced as appropriate. The drawings should be viewed according to the orientation of the reference numerals.

[0010] (First embodiment) Please refer to Figures 1 and 2. The main feature of the gear device 10 relates to a rotation detector 60, which will be described later, but the peripheral structure will be described first.

[0011] The gear device 10 connects a first mating member 12 and a second mating member 14, and can rotate the second mating member 14 relative to the first mating member 12. The gear device 10 of this embodiment is incorporated into a joint of a multi-joint arm of a robot device. The first mating member 12 and the second mating member 14 of this embodiment are either a base member or an arm member that configure the multi-joint arm. The robot device is, for example, an industrial robot, a service robot, etc.

[0012] The eccentric oscillating gear device 10 includes an external gear 16 and an internal gear 18 that mesh with each other. One of the external gear 16 and the internal gear 18 serves as an oscillating gear 20, and the other serves as a meshing gear 22 that meshes with the oscillating gear 20. The oscillating gear 20 in this embodiment is the external gear 16. The external gear 16 and the internal gear 18 function as a reduction mechanism that reduces the rotation of crankshafts 24A to 24C, which will be described later.

[0013] The gear device 10 further includes a plurality of crankshafts 24A-24C arranged at positions offset from the center CL1 of the oscillating gear 20 in the radial direction of the oscillating gear 20, and crankshaft gears 26A-26C provided on at least one of the crankshafts 24A-24C. The gear device 10 further includes a casing 28 that houses the crankshafts 24A-24C, etc., carriers 32A, 32B that support the crankshafts 24A, 24B, 24C via a crank bearing 30, and an output member 34 that takes out, from the reduction mechanism, output rotation that has been reduced in speed relative to the rotation of the crankshafts 24A-24C.

[0014] The oscillating gear 20 (externally toothed gear 16) is provided individually corresponding to each of a plurality of eccentric bodies 40 described later, and is supported relatively rotatably by the corresponding eccentric body 40 via an eccentric body bearing 36. The plurality of crankshafts 24A to 24C may be disposed at positions offset relative to the center CL1 of any one of the oscillating gears 20.

[0015] The number of crankshafts 24A to 24C in this embodiment is three. The crankshafts 24A to 24C are arranged at intervals in the circumferential direction of the oscillating gear 20. The crankshafts 24A to 24C penetrate the oscillating gear 20 in the axial direction of the oscillating gear 20.

[0016] The crankshafts 24A to 24C include a shaft body 38 supported by the carriers 32A and 32B, and a plurality of eccentric bodies 40 that can rotate integrally with the shaft body 38. An axis CL2 of the eccentric body 40 is eccentric with respect to a rotation center line CL3 of the crankshafts 24A to 24C. The eccentric body 40 can oscillate the oscillating gear 20 by rotating about the rotation center line CL3 of the crankshafts 24A to 24C. The eccentric phases of the plurality of eccentric bodies 40 are shifted by 360° / M when the number of the eccentric bodies 40 is M (two in this embodiment). The number of the eccentric bodies 40 is not particularly limited, and may be either one or three or more.

[0017] The number of crankshaft gears 26A-26C in this embodiment is three. The crankshaft gears 26A-26C are provided individually on the crankshafts 24A-24C, respectively. Like the crankshafts 24A-24C, the crankshaft gears 26A-26C are also disposed at intervals in the circumferential direction of the oscillating gear 20 at positions offset from the center CL1 of the oscillating gear 20 in the radial direction of the oscillating gear 20.

[0018] The crankshaft gears 26A to 26C are provided to be rotatable integrally with the crankshafts 24A to 24D by recess-and-projection fitting, etc. The crankshaft gears 26A to 26C of the present embodiment are fixed to the crankshafts 24A to 24C by a retaining ring 42 so as to be immovable in the axial direction.

[0019] The crankshaft gears 26A to 26C are spur gears. The crankshaft gears 26A to 26C have a plurality of teeth 44 on their outer peripheries. The crankshaft gears 26A to 26C mesh with an input gear 46 that inputs rotation to the crankshaft gears 26A to 26C. In FIG. 2, the outline of the outer periphery of the crankshaft gears 26A to 26C is shown using a pitch circle formed by the plurality of teeth 44. Similarly, the outline of the outer periphery of the input gear 46 is shown using a pitch circle formed by the plurality of teeth.

[0020] The input gear 46 can be rotated by rotational power transmitted from a drive source. The drive source in this embodiment is a motor 48. Other drive sources may be gear motors, engines, etc. The input gear 46 in this embodiment is provided at the tip of the output shaft of the motor 48. The input gear 46 in this embodiment is meshed with each of the crankshaft gears 26A to 26C, and the rotation of the input gear 46 is distributed to each of the crankshaft gears 26A to 26C. This allows the crankshaft gears 26A to 26C to rotate in the same direction at the same rotation speed. In addition, the crankshafts 24A to 24C rotated by each of the crankshaft gears 26A to 26C can also rotate in the same direction at the same rotation speed.

[0021] The casing 28 of this embodiment includes a first casing member 50 provided at a position overlapping the oscillating gear 20 in the radial direction of the oscillating gear 20, and a second casing member 52 provided at a position overlapping the crankshaft gears 26A to 26C in the radial direction of the oscillating gear 20. The casing members 50, 52 are connected using bolts or the like. In this embodiment, the internal gear 18 is provided on the inner periphery of the first casing member 50. The second casing member 52 functions as a motor adapter that connects the first casing member 50 and the motor 48. The first mating member 12 is attached to the casing 28 using bolts or the like.

[0022] The carriers 32A, 32B include a first carrier 32A disposed on one axial side (the right side in the figure) and a second carrier 32B disposed on the other axial side. The first carrier 32A and the second carrier 32B are connected by a pin body 54 that penetrates the external gear 16. The second mating member 14 is attached to the second carrier 32B using a bolt or the like.

[0023] The output member 34 in this embodiment is the second carrier 32B. The output member 34 outputs the output rotation of the reduction mechanism formed by the external gear 16 and the internal gear 18 to one of the first mating member 12 and the second mating member 14, thereby allowing the second mating member 14 to rotate relatively to the first mating member 12.

[0024] The operation of the gear device 10 described above will be described. When the input gear 46 rotates, the rotation of the input gear 46 is transmitted to at least one of the crankshafts 24A to 24C via the crankshaft gears 26A to 26C, causing the crankshafts 24A to 24C to rotate. When the crankshafts 24A to 24C rotate, the oscillating gear 20 is oscillated by the eccentric body 40 of the crankshafts 24A to 24C. When the oscillating gear 20 oscillates, the meshing positions of the external gear 16 and the internal gear 18 change sequentially in the circumferential direction. As a result, either the external gear 16 or the internal gear 18 rotates on its axis, and the rotation component is taken out from the output member 34 as output rotation, causing the output member 34 to rotate. When the output member 34 rotates, the second mating member 14 rotates relative to the first mating member 12.

[0025] We will now move on to an explanation of the rotation detector 60. Please refer to Figures 2 and 3. Hereinafter, when simply referring to the "axial direction," the "circumferential direction," and the "radial direction," these refer to the axial direction, the circumferential direction, and the radial direction of the meshing gears 22. The circumferential direction and the radial direction of the meshing gears 22 refer to the circumferential direction and the radial direction of a circle centered on the central axis CL4 of the meshing gears 22.

[0026] The crankshafts 24A-24C in the embodiment include a first crankshaft 24A and a second crankshaft 24B adjacent to each other in the circumferential direction. The crankshaft gears 26A-26C include a first crankshaft gear 26A provided on the first crankshaft 24A and a second crankshaft gear 26B provided on the second crankshaft 24B. The first crankshaft gear 26A and the second crankshaft gear 26B are also adjacent to each other in the circumferential direction, similar to the first crankshaft 24A and the second crankshaft 24B.

[0027] The gear device 10 includes a rotation detector 60 that faces the teeth 44 of the crankshaft gears 26A, 26B in the radial direction of the crankshaft gears 26A, 26B and detects the rotation of the crankshaft gears 26A, 26B. The rotation detector 60 in this embodiment is a magnetic encoder. The rotation detector 60 includes a substrate 62 and detection processing units 66A, 66B provided on main surfaces 64A, 64B of the substrate 62.

[0028] The substrate 62 has a first main surface 64A and a second main surface 64B which are provided on both sides of the substrate 62 in the thickness direction. The second main surface 64B is provided on the opposite side of the substrate 62 in the thickness direction from the first main surface 64A. The substrate 62 is arranged so that its thickness direction is aligned with the circumferential direction (the tangent direction of a circle centered on the central axis CL4 of the meshing gear 22) when viewed from the axial direction, and extends in the radial direction. The substrate 62 is arranged at a position shifted in the circumferential direction with respect to the crankshaft gears 26A, 26B.

[0029] The rotation detector 60 is fixed to the first carrier 32A, which is synchronized with the revolution component of the crankshaft gears 26A-26C when the gear device 10 is in operation. Here, "synchronization" refers to maintaining a state in which the crankshaft gears 26A-26C do not rotate when they do not revolve, and rotating at a speed of the same circumferential component as the revolution component of the crankshaft gears 26A-26C when they revolve. The rotation detector 60 is fixed, for example, to the axial side of the first carrier 32A. The method of fixing the rotation detector 60 to the first carrier 32A is not particularly limited. The substrate 62 of the rotation detector 60 may be fixed to the first carrier 32A, for example, via a mounting base (not shown).

[0030] A circle circumscribing the crankshaft gears 26A-26C as viewed in the axial direction is defined as a circumscribing circle C. The circumscribing circle C has its center on the central axis CL4 of the meshing gears 22. The base plate 62 includes a fixed portion 62a provided at a position overlapping with the first carrier 32A in the axial direction as viewed in the axial direction, and an extending portion 62b extending radially outward beyond the circumscribing circle C. The fixed portion 62a of the base plate 62 is fixed to the first carrier 32A as described above.

[0031] The detection processing units 66A, 66B face the teeth 44 of the crankshaft gears 26A, 26B in the radial direction of the crankshaft gears 26A, 26B. The detection processing units 66A, 66B include a first detection processing unit 66A provided on the first main surface 64A of the substrate 62 and a second detection processing unit 66B provided on the second main surface 64B of the substrate 62. The first detection processing unit 66A faces the teeth 44 of the first crankshaft gear 26A in the radial direction of the first crankshaft gear 26A. The second detection processing unit 66B faces the teeth 44 of the second crankshaft gear 26B in the radial direction of the second crankshaft gear 26B.

[0032] The gear device 10 includes wiring 68 that transmits an output signal that is the detection result of the rotation detector 60. The wiring 68 forms at least a part of a signal transmission path that transmits a signal between the rotation detector 60 and a control device 82 (described later). The wiring 68 includes a signal line that forms the signal transmission path. In addition, the wiring 68 may include a power supply line for supplying power to the rotation detector 60, an earth wire for grounding, etc.

[0033] The wiring 68 is mechanically connected to the substrate 62. The wiring 68 may be detachably connected to a terminal block mounted on the substrate 62, or may be non-detachably connected to the substrate 62 using solder or the like. An output signal output from the detection processing units 66A, 66B of the substrate 62 is transmitted to the control device 82 through the wiring pattern and wiring 68 of the substrate 62. The wiring 68 is connected to the extension portion 62b of the substrate 62, and is provided so as to extend in the circumferential direction from the connection position.

[0034] Please refer to Figures 3 and 4. Figure 4 is a block diagram showing some of the functional blocks of a gear motor 80 that combines the gear device 10 of the embodiment with a motor 48. Each block shown in the block diagrams in this specification can be realized in terms of hardware by electronic components such as a computer's CPU (Central Processing Unit), circuits, mechanical devices, etc., and in terms of software by a computer program, etc. Here, functional blocks realized by the cooperation of these are depicted. It will be understood by those skilled in the art that these functional blocks can be realized in various ways by combining hardware and software.

[0035] The gear motor 80 includes a control device 82 in addition to the gear device 10 and the motor 48. The control device 82 is a computer such as a microcomputer, and is configured by combining a CPU, a ROM, a RAM, etc. The control device 82 can control the motor 48 using the output signal of the rotation detector 60. The control method of the control device 82 is not particularly limited. For example, the control device 82 may specify the rotation angle of the output member 34 using an output signal indicating the rotation state of the crankshaft gears 26A, 26B, and control the output of the motor 48 so that the output member 34 is at a target rotation angle.

[0036] The detection processing units 66A, 66B of the rotation detector 60 used in the gear device 10 are ICs such as an encoder IC or a Hall IC. The detection processing units 66A, 66B can detect the rotation of the crankshaft gears 26A, 26B by a detection element 84 incorporated therein. The detection processing units 66A, 66B can process the detection signal detected by the detection element 84, and then output an output signal representing the detection result by the detection processing units 66A, 66B to the control device 82.

[0037] The detection processing units 66A and 66B constituted by ICs are provided on the main surfaces 64A and 64B of the substrate 62 by being mounted thereon. This mounting method is not particularly limited. When using a bias magnet 86, which will be described later, as in this embodiment, the bias magnet 86 may be fixed to the main surfaces 64A and 64B of the substrate 62 by adhesion or the like, and the ICs constituting the detection processing units 66A and 66B may be fixed to the bias magnet 86 by adhesion or the like. In this case, the terminals of the ICs constituting the detection processing units 66A and 66B and the wiring pattern of the substrate 62 may be electrically connected using wire bonding or the like. In addition, the detection processing units 66A and 66B may be mounted by fixing the terminal pins of the ICs constituting the detection processing units 66A and 66B to the lands of the wiring pattern of the substrate 62 by solder or the like.

[0038] The detection element 84 incorporated in the detection processing units 66A, 66B is, for example, a magnetic resistance element that detects changes in a magnetic field. The rotation detector 60 of this embodiment includes a bias magnet 86 that applies a bias magnetic field to the detection element 84. FIG. 3 shows some magnetic field lines La of the bias magnetic field. The bias magnet 86 is arranged so that different polarities (N pole and S pole) are aligned in the radial direction of the crankshaft gears 26A, 26B that are the object of detection by the detection element 84. In this embodiment, the magnetization directions of the bias magnets 86 of each detection processing unit 66A, 66B are the same, but may be opposite.

[0039] The crankshaft gears 26A, 26B are made of soft magnetic materials such as electromagnetic steel sheets and silicon iron so as to be magnetized by the bias magnetic field. Due to the influence of the convex and concave portions formed by the multiple teeth 44 of the crankshaft gears 26A, 26B, the magnetic field applied to the detection element 84 changes with the rotation of the crankshaft gears 26A, 26B. The detection element 84 detects the change in the bias magnetic field caused by the rotation of the crankshaft gears 26A, 26B as a change in voltage, and obtains the detected change in voltage as a detection signal (analog signal). At this time, the detection element 84 obtains one period of a signal as the detection signal every time the crankshaft gears 26A, 26B rotate by one pitch. The principle of detecting the rotation of the gears using the bias magnet 86 is well known, so a detailed description thereof will be omitted here.

[0040] The detection processing units 66A, 66B process the detection signal of the detection element 84 using a predetermined processing method to obtain an output signal (rotation angle, rotation speed, etc.) indicating the rotation state of the crankshaft gears 26A, 26B. By using this output signal, the rotation state of the crankshafts 24A, 24B that rotate integrally with the crankshaft gears 26A, 26B can also be identified.

[0041] The processing method of the detection processing units 66A, 66B may be, for example, an absolute method in which an absolute position signal indicating the absolute position of the rotation angle of the crankshaft gears 26A, 26B is obtained as an output signal using the detection signal of the detection element 84. When the absolute method is used, a single-turn absolute method in which only an absolute position signal indicating the absolute position of the rotation angle within one rotation of the crankshaft gears 26A, 26B is obtained as an output signal. Alternatively, a multi-turn absolute method in which a rotation speed signal indicating the rotation speed of the crankshaft gears 26A, 26B is obtained as an output signal together with the absolute position signal may be used.

[0042] Alternatively, the processing method of the detection processing units 66A and 66B may be an incremental method in which a detection signal from the detection element 84 is used to obtain a relative position signal indicating the relative position of the rotation angle of the crankshaft gears 26A and 26B as an output signal. The relative position signal may include, for example, an A-phase signal and a B-phase signal having a phase difference of 90°, as well as a Z-phase signal indicating the origin position of the crankshaft gears 26A and 26B. When the incremental method is used, for example, a plurality of detection elements 84 may be used to obtain, as detection signals, sine and cosine signals that are two-phase analog signals having a phase difference of 90°. In this case, pulse signals that are A-phase and B-phase signals may be obtained as output signals by performing AD conversion and interpolation division of the two-phase analog signals.

[0043] When the incremental method is used, the Z-phase signal may be detected using the detection element 84. This specific example is not particularly limited. As an example, this may be realized by providing the crankshaft gears 26A, 26B with a single detection tooth portion for detecting the Z-phase signal and detecting the detection tooth portion by the detection element 84. The detection tooth portion is provided on the crankshaft gears 26A, 26B at a position axially shifted from the multiple teeth 44 of the crankshaft gears 26A, 26B that mesh with the input gear 46.

[0044] The processing method of the detection processing units 66A, 66B may be, for example, an analog output method that uses the above-mentioned two-phase analog signals (sine signal and cosine signal) obtained by the detection element 84 as output signals. The sine signal and cosine signal function as output signals indicating the rotation angles of the crankshaft gears 26A, 26B. For example, the control device 82 may calculate an arctangent signal (θ=arctan(sin / cos)) of the sine signal and cosine signal, and use the angle signal θ indicating the rotation angle of the crankshaft gears 26A, 26B to identify the rotation angle of the crankshaft gears 26A, 26B.

[0045] The detection processing units 66A and 66B may be capable of executing each of the multiple processing methods described above, or may be capable of executing any one of them. In the case of using any of the processing methods, the detailed processing procedure is not particularly limited. This detailed processing procedure may be executed using a known processing procedure, or may be executed using another processing procedure that can achieve the same purpose.

[0046] The first detection processing unit 66A detects the rotation of the first crankshaft gear 26A by the detection element 84 and processes the detected detection signal. The second detection processing unit 66B detects the rotation of the second crankshaft gear 26B by the detection element 84 and processes the detected detection signal.

[0047] The first detection processing unit 66A and the second detection processing unit 66B process the detection signal using different processing methods. For example, the first detection processing unit 66A may process the detection signal using a single-turn absolute method, and the second detection processing unit 66B may process the detection signal using a multi-turn absolute method. Alternatively, for example, the first detection processing unit 66A may process the detection signal using an analog output method, and the second detection processing unit 66B may process the detection signal using an incremental method. In any case, the specific content and combination of the processing methods by which the detection processing units 66A and 66B process the detection signal using different processing methods are not particularly limited.

[0048] In this embodiment, the detection processing units 66A and 66B transmit the output signal to the control device 82 using a wired transmission method using wiring 68. When using the absolute method, the output signal transmission method may be either a serial interface (BiSS, SSI, SPI, I2C, etc.) or a parallel interface.

[0049] A power source 88 and a user interface 89 are electrically connected to the control device 82. The power source 88 is used to supply power to electrical devices (motor 48, rotation detector 60) including the control device 82. Power is supplied from the power source 88 via the control device 82 to electrical devices other than the control device 82. The user interface 89 is used to input or output information to the control device 82. The user interface 89 is, for example, a keyboard, a display, etc.

[0050] The effects of the above gear device 10 will now be described.

[0051] The gear device 10 of this embodiment includes a rotation detector 60 that detects the rotation of the crankshaft gears 26A, 26B. Therefore, in the gear device 10 including the multiple crankshafts 24A to 24C, the rotation of the crankshaft gears 26A, 26B can be detected by the rotation detector 60. In addition, since the rotation detector 60 is disposed in a location facing the teeth 44 of the crankshaft gears 26A, 26B which is likely to become a dead space, the rotation detector 60 can be incorporated into the gear device 10 while reducing the size of the gear device 10.

[0052] The rotation detector 60 includes a first detection processor 66A facing the first crankshaft gear 26A and a second detection processor 66B facing the second crankshaft gear 26B. Thus, the first detection processor 66A and the second detection processor 66B can detect the rotation of the different crankshaft gears 26A and 26B. In addition, by providing a plurality of detection processors 66A and 66B, the rotation detector 60 can be made redundant. Also, the board 62 can be shared to detect the rotation of the different crankshaft gears 26A and 26B. Thus, the number of parts can be reduced compared to using a dedicated board 62 for each individual detection processor 66A and 66B.

[0053] The first detection processing unit 66A and the second detection processing unit 66B process the detection signals using different processing methods, so that each detection processing unit 66A, 66B can output a different output signal indicating the rotation state of the crankshaft gears 26A, 26B.

[0054] The wiring 68 is connected to an extension 62b of the substrate 62 extending radially outward from the circumscribing circle C. If the extension 62b is not provided on the substrate 62 and the crankshaft gears 26A to 26C revolve by the rotation of the first carrier 32A, it is necessary to extend the wiring 68 from the substrate 62 in the axial direction opposite to the first carrier 32A in order to avoid interference between the crankshaft gears 26A to 26C and the wiring 68. Accordingly, it is necessary to secure an extra axial dimension between the side member and the substrate 62 in order to avoid interference between the wiring 68 and a side member (here, the second casing member 52) located on the axial direction opposite to the first carrier 32A with respect to the substrate 62. In contrast, if the wiring 68 is connected to the extension 62b of the substrate 62, it is not necessary to extend the wiring 68 in the axial direction opposite to the first carrier 32A, and it is not necessary to secure an extra axial dimension between the side member and the substrate 62.

[0055] Next, other improvements of the gear device 10 will be described.

[0056] See Figures 2 and 5. The relative rotatable angle range between the casing 28 and the carriers 32A, 32B (hereinafter referred to as the movable angle range) is less than 360°. This movable angle range refers to the angle range around the central axis CL4 of the meshing gear 22. This assumes, for example, a case in which the gear device 10 is incorporated into a joint of a multi-joint arm of a robot device, as in this embodiment. To achieve this, for example, the relative rotatable angle range between the casing 28 and the carriers 32A, 32B may be mechanically limited or controlled by the control device 82.

[0057] The wiring 68 includes a fixed portion 90 whose position relative to the casing 28 is fixed, and a movable portion 92 provided between the fixed portion 90 of the wiring 68 and the substrate 62. The fixed portion 90 is fixed in position relative to the casing 28, for example, by being inserted into an extraction hole 94 provided in the casing 28. The fixed portion 90 is extracted from the extraction hole 94 into the external space outside the gear device 10, and then connected to the control device 82.

[0058] The carrier 32A is rotatable between a first angular position Pa (see FIG. 2) on one circumferential side of the movable angular range (counterclockwise in the figure) and a second angular position Pb (see FIG. 5) on the other circumferential side of the movable angular range (clockwise in the figure). The carrier 32A can rotate from the first angular position Pa to the second angular position Pb by rotating in a first rotation direction (hereinafter, for convenience, referred to as a forward rotation direction Da). The carrier 32A can also rotate from the second angular position Pb to the first angular position Pa by rotating in a second rotation direction (hereinafter, for convenience, referred to as a reverse rotation direction Db) that is opposite to the forward rotation direction Da.

[0059] When the carrier 32A rotates between the first angular position Pa and the second angular position Pb, the crankshaft gears 26A-26C and the rotation detector 60 rotate in the same direction and by the same rotation angle as the carrier 32A. The movable part 92 of the wiring 68 can move following the rotation detector 60 when the rotation detector 60 rotates together with the carrier 32A between the first angular position Pa and the second angular position Pb.

[0060] The movable part 92 of the wiring 68 is disposed so as to surround the plurality of crankshaft gears 26A-26C when the carrier 32A is in the first angular position Pa. At this time, the movable part 92 of the wiring 68 is disposed radially outward of the circumscribing circle C described above. At this time, the movable part 92 of the wiring 68 is provided so as to exist in a first circumferential range Ra. In contrast, the movable part 92 of the wiring 68 is provided so as to exist in a second circumferential range Rb narrower than the first circumferential range Ra when the carrier 32A is in the second angular position Pb.

[0061] When the carrier 32A rotates in the forward rotation direction Da from the first angular position Pa to the second angular position Pb, the movable part 92 of the wiring 68 is pushed to the other circumferential side (clockwise in the figure) by the rotation detector 60. This reduces the circumferential range in which it exists from the first circumferential range Ra to the second circumferential range Rb. When the carrier 32A rotates in the reverse rotation direction Db from the second angular position Pb to the first angular position Pa, the movable part 92 of the wiring 68 is pulled to one circumferential side (counterclockwise in the figure) by the rotation detector 60. This increases the circumferential range in which it exists from the second circumferential range Rb to the first circumferential range Ra. In this way, the movable part 92 of the wiring 68 can move following the rotation detector 60 so that the circumferential range in which it exists increases or decreases when the carrier 32A rotates between the first angular position Pa and the second angular position Pb.

[0062] In this manner, the wiring 68 is disposed so as to surround the plurality of crankshaft gears 26A to 26C. Therefore, when the carrier 32A rotates within a movable angle range of less than 360° relative to the casing 28, a part of the wiring 68 (movable part 92) can be moved following the movement of the rotation detector 60. As a result, it becomes possible to allow the carrier 32A and the like to rotate relative to the casing 28 while keeping the rotation detector 60 and the control device 82 electrically connected by the wiring 68.

[0063] As described above, when the carrier 32A rotates in the forward rotation direction Da during operation of the gear device 10, the rotation detector 60 rotates together with the carrier 32A, which may cause slack in the wiring 68. As a measure against slack in the wiring 68, the gear device 10 is provided with an interference prevention mechanism 100 that prevents interference between the crankshaft gears 26A-26C and the wiring 68 due to slack in the wiring 68 caused by rotation of the carrier 32A. The interference prevention mechanism 100 of this embodiment is provided with a guide 102 that restricts radially inward movement of the wiring 68 by abutting against the movable part 92 of the wiring 68 from the radially inner side, and a length adjustment mechanism 104 that can adjust the payout length of the movable part 92 of the wiring 68 as the carrier 32A rotates.

[0064] The guide 102 in this embodiment is fixed to the carrier 32A and can rotate integrally with the carrier 32A. The guide 102 is provided so as to surround the plurality of crankshaft gears 26A to 26C when viewed from the axial direction. When the movable part 92 of the wiring 68 tries to loosen, the guide 102 comes into contact with the movable part 92 from the radially inner side, thereby restricting the radially inward movement of the movable part 92.

[0065] The length adjustment mechanism 104 of this embodiment is a cord reel. This length adjustment mechanism 104 is provided between the movable part 92 and the fixed part 90 of the wiring 68. The cord reel constituting the length adjustment mechanism 104 is fixed to the casing 28. In this embodiment, the movable part 92 and the fixed part 90 of the wiring 68 are composed of separate wiring members and are electrically connected to each other. Although not shown, the length adjustment mechanism 104 includes a drum around which the wiring member constituting the movable part 92 of the wiring 68 is wound, and a biasing member such as a spiral spring that biases the drum in the winding direction. When the carrier 32A rotates in the forward rotation direction Da, the length adjustment mechanism 104 winds up the movable part 92 of the wiring 68 using the biasing force of the biasing member, thereby preventing the wiring 68 from loosening. When the carrier 32A rotates in the reverse rotation direction Db, the length adjustment mechanism 104 can unwind the wiring 68 from the drum against the biasing force of the biasing member when the movable part 92 of the wiring 68 is pulled. This makes it possible for the length adjustment mechanism 104 to adjust the length of the movable portion 92 of the wiring 68 that is pulled out.

[0066] When the carrier 32A is about to rotate in the forward rotation direction Da, the guide 102 can restrict movement of the wiring 68 toward the crankshaft gears 26A-26C due to slack in the movable part 92 of the wiring 68. At the same time, the length adjustment mechanism 104 winds up the movable part 92 of the wiring 68, thereby reducing the unreeled length and preventing slack in the wiring 68 itself.

[0067] When the carrier 32A attempts to rotate in the reverse rotation direction Db and the movable part 92 of the wiring 68 attempts to be pulled, the movable part 92 comes into contact with the guide 102 from the radially inner side and is guided and pulled. At the same time, the movable part 92 of the wiring 68 is pulled out from the length adjustment mechanism 104, thereby making it possible to increase the length of the pulled out part.

[0068] The interference prevention mechanism 100 described above makes it possible to prevent interference between the crankshaft gears 26A to 26C and the wiring 68 even when the wiring 68 tends to loosen as the carrier 32A rotates.

[0069] (Second embodiment) See Fig. 6. The gear device 10 of the second embodiment differs in that, in addition to the rotation detector 60 (hereinafter referred to as the first rotation detector 60) described so far, it includes a second rotation detector 110 capable of detecting the rotation of the first carrier 32A. The second rotation detector 110 is an encoder. The second rotation detector 110 includes a detected portion 112 provided on the inner periphery of the casing 28, and a third detection processing portion 114 facing the detected portion 112 in the radial direction of the casing 28 (meshing gears 22).

[0070] The third detection processing unit 114 is provided at the outer circumferential end of the substrate 62 of the first rotation detector 60. The third detection processing unit 114 is, for example, an IC such as an encoder IC or a Hall IC, similar to the detection processing units 66A and 66B of the rotation detector 60. The third detection processing unit 114 can detect the rotation of the first carrier 32A by detecting the detected portion 112 with a detection element (not shown) incorporated therein. The detection element of the third detection processing unit 114 and the detected portion 112 are, for example, a combination of a magnetic resistance element and a magnetic scale, or a combination of an optical sensor and an optical scale.

[0071] The third detection processing unit 114, like the detection processing units 66A and 66B of the first rotation detector 60, can obtain an output signal indicating the rotational state (rotation angle, etc.) of the first carrier 32A by processing a detection signal obtained by detecting the detection target unit 112 with a detection element. The method of processing the detection signal by this third detection processing unit 114 is not particularly limited, and like the above-mentioned detection processing units 66A and 66B, at least one of the absolute method, incremental method, and analog output method may be used. The third detection processing unit 114 can output the obtained output signal to the control device 82.

[0072] As a result, when the first carrier 32A rotates, the rotation of the first carrier 32A can be detected by the second rotation detector 110. When the casing 28 rotates, the rotation of the casing 28 can also be detected by the second rotation detector 110.

[0073] Variations of the above components will now be described.

[0074] There are no particular limitations on the specific examples of the first mating member 12 and the second mating member 14. For example, one of the first mating member 12 and the second mating member 14 may be a base that supports the gear device 10, and the other may be a part of a driven machine such as a conveyor, a wheel, or a machine tool.

[0075] In the above embodiment, the oscillating gear 20 of the gear device 10 is the external gear 16. Alternatively, the oscillating gear 20 may be the internal gear 18.

[0076] In the embodiment, an example has been described in which the carriers 32A and 32B rotate relative to the casing 28, and the carriers 32A and 32B serve as the output member 34. Alternatively, the casing 28 may rotate relative to the carriers 32A and 32B, and the casing 28 may serve as the output member 34. In this case, since the carrier 32 does not rotate, measures against loosening of the wiring due to the rotation of the carrier 32 are not required (that is, twisting of the wiring can be avoided). In addition, the second casing member 52 may be fixed to the carrier 32A. In addition, the movable angle range of the casing 28 and the carriers 32A and 32B may be unlimited.

[0077] The crankshaft gears 26A-26C may be provided on at least one of the crankshafts 24A-24C among the plurality of crankshafts 24A-24C, and the number of the crankshaft gears 26A-26C is not particularly limited. For example, the crankshaft gears 26A-26C may be one, two, four or more. When the crankshaft gears 26A-26C are one, only one of the crankshafts 24A-24C may be driven by the input gear 46, and the other crankshafts 24A-24C may be driven by the oscillation of the oscillating gear 20. In this case as well, the plurality of crankshafts 24A-24C can rotate in the same direction at the same rotational speed.

[0078] In the embodiment, a magnetic encoder has been described as an example of the rotation detector 60. The type of the rotation detector 60 is not particularly limited, and it may be an optical encoder, a mechanical encoder, or the like.

[0079] The transmission method of the output signal between the rotation detector 60 and the control device 82 is not particularly limited. This transmission method may be a wired transmission method as in the embodiment, or a wireless transmission method. When the wireless transmission method is used, it is possible to eliminate the need for measures against slack in the wiring 68 of the embodiment. When the wireless transmission method is used, the rotation state of the crankshaft gears 26A, 26B is obtained by the control device 82 using the rotation detector 60 by remote measurement under the control of the control device 82. When the wireless transmission method is used, a secondary battery built into the rotation detector 60 may be used as a power source for the rotation detector 60.

[0080] When the wired transmission method is used, if the rotation detector 60 remains stationary together with the carriers 32A and 32B during operation of the gear device 10, the measures against slackening of the wiring 68 in the embodiment can be eliminated. In addition, when the wired transmission method is used and the rotation detector 60 rotates together with the carriers 32A and 32B during operation of the gear device 10, it is not essential to use the wiring 68 disposed in the casing 28 as in the embodiment. In this case, for example, a rotation connection connector may be incorporated in the gear device 10. The signal transmission path from the rotation detector 60 to the control device 82 includes an external wiring that is outside the gear device 10 and connected to the control device 82. The rotation connection connector becomes a part of this signal transmission path and electrically connects the rotation detector 60 to the external wiring. The rotation connection connector is integrated into the casing 28, for example. The rotation connection connector can maintain the state in which the rotation detector 60 is electrically connected to the external wiring even when the rotation detector 60 rotates together with the carriers 32A and 32B with respect to the external wiring. The connector for rotational connection may directly electrically connect the external wiring and the rotation detector 60, or may electrically connect them via wiring 68 arranged inside the casing 28. A specific example of the connector for rotational connection is not particularly limited, and for example, a slip ring mechanism combining a slip ring and a brush, a liquid metal rotary connector, or the like may be used.

[0081] The rotation detector 60 of the embodiment has been described as including the first detection processing unit 66A and the second detection processing unit 66B that face the teeth 44 of different crankshaft gears 26A and 26B. Alternatively, the rotation detector 60 may include only a single detection processing unit that faces the teeth of a single crankshaft gear.

[0082] The first detection processing unit 66A and the second detection processing unit 66B may process the detection signals using the same processing method.

[0083] The substrate 62 does not have to include the extending portion 62b. In this case, the wiring 68 may be connected to the fixed portion 62a of the substrate 62.

[0084] The wiring 68 does not have to be arranged so as to surround the multiple crankshaft gears 26A, 26B. To achieve this, for example, in the case where the wiring 68 includes the movable part 92, the movable part 92 of the wiring 68 may be provided only on the radial outside of a single crankshaft gear.

[0085] The gear device 10 does not necessarily have to include the interference prevention mechanism 100. There are no particular limitations on the specific example of the interference prevention mechanism 100. The interference prevention mechanism 100 may be configured with only one of the guide 102 and the length adjustment mechanism 104 described above. In addition, instead of the guide 102 and the length adjustment mechanism 104 described above, the interference prevention mechanism 100 may include a rotation connection connector that electrically connects the rotation detector 60 and the wiring 68 to external wiring.

[0086] There is also no particular limitation on the specific example of the guide 102. Although the guide 102 has been described as a plate-shaped member extending in an arc shape in the embodiment, it may be a cylindrical member extending in an arc shape. Also, although the guide 102 has been described as being composed of a single member, it may be composed of multiple members.

[0087] A specific example of the length adjustment mechanism 104 is not limited. The length adjustment mechanism 104 may be, for example, a U-turn mechanism that holds a part of the wiring 68 on the fixed part 90 side from the movable part 92 in a U-turned state and varies the length of the U-turned part in conjunction with the variation of the payout length of the movable part 92 of the wiring 68. When this mechanism is used, the length of the U-turn part can be decreased in conjunction with the increase of the payout length of the movable part 92 of the wiring 68, and the length of the U-turn part can be increased in conjunction with the decrease of the payout length. When the U-turn mechanism is used, the length of the movable part 92 and the U-turn part of the wiring 68 increases or decreases, but the amount of slack in the movable part 92 of the wiring 68 can be reduced compared to when the U-turn mechanism is not used. As a result, interference between the crankshaft gears 26A to 26C and the wiring 68 can be prevented compared to when the U-turn mechanism is not used.

[0088] The above-mentioned embodiment and modified forms are merely examples. The technical ideas abstracted from these should not be interpreted as being limited to the contents of the embodiment and modified forms. Many design changes are possible in the contents of the embodiment and modified forms, such as changing, adding, or deleting components. In the above-mentioned embodiment, the contents in which such design changes are possible are emphasized by adding the notation "embodiment". However, design changes are also permitted even in contents without such notation. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added. [Explanation of symbols]

[0089] 10...eccentric oscillating gear device, 20...oscillating gear, 24A...first crankshaft, 24B...second crankshaft, 26A...first crankshaft gear, 26B...second crankshaft gear, 32A...carrier, 44...tooth portion, 60...rotation detector, 62...substrate, 62b...extension portion, 64A...first main surface, 64B...second main surface, 66A...first detection processing unit, 66B...second detection processing unit, 68...wiring, 100...interference prevention mechanism.

Claims

1. A oscillating gear, A plurality of crankshafts are disposed at positions offset from the center of the oscillating gear in a radial direction of the oscillating gear; a crankshaft gear provided on at least one of the crankshafts and receiving rotation therefrom, a rotation detector facing a toothed portion of the crankshaft gear and detecting rotation of the crankshaft gear, The plurality of crankshafts include a first crankshaft provided with a first crankshaft gear; a second crankshaft provided with a second crankshaft gear; The rotation detector includes: A substrate; a first detection processing unit provided on a first main surface of the substrate and facing a tooth portion of the first crankshaft gear; a second detection processing unit provided on a second main surface of the substrate opposite the first main surface and facing a tooth portion of the second crankshaft gear.

2. The first detection processing unit detects rotation of the first crankshaft gear and processes the detected detection signal; the second detection processing unit detects rotation of the second crankshaft gear and processes the detected detection signal; 2. The eccentric oscillating gear device according to claim 1, wherein the first detection processing section and the second detection processing section process the detection signals using different processing methods.

3. A oscillating gear, A plurality of crankshafts are disposed at positions offset from the center of the oscillating gear in a radial direction of the oscillating gear; a plurality of crankshaft gears provided on at least one of the crankshafts and receiving rotation therefrom; a rotation detector facing a tooth portion of the crankshaft gear and detecting rotation of the crankshaft gear; a wiring for transmitting a detection result of the rotation detector, The rotation detector includes a substrate; the base plate includes an extension portion that extends radially outward beyond a circumscribing circle that circumscribes the plurality of crankshaft gears when viewed in the axial direction, The wiring is connected to the extension portion.

4. A oscillating gear, A plurality of crankshafts are disposed at positions offset from the center of the oscillating gear in a radial direction of the oscillating gear; a plurality of crankshaft gears provided on at least one of the crankshafts and receiving rotation therefrom; a rotation detector facing a tooth portion of the crankshaft gear and detecting rotation of the crankshaft gear; a wiring for transmitting a detection result of the rotation detector, The wiring is disposed so as to surround the plurality of crankshaft gears when viewed in the axial direction.

5. A oscillating gear, A plurality of crankshafts are disposed at positions offset from the center of the oscillating gear in a radial direction of the oscillating gear; a crankshaft gear provided on at least one of the crankshafts and receiving rotation therefrom, a rotation detector facing a tooth portion of the crankshaft gear and detecting rotation of the crankshaft gear; Wiring for transmitting the detection result of the rotation detector; a carrier to which the rotation detector is fixed; an interference prevention mechanism that prevents interference between the crankshaft gear and the wiring due to slack in the wiring caused by rotation of the carrier.

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