JP7654522B2 - Eccentric oscillating gear device - Google Patents

Description

This disclosure relates to an eccentric oscillating gear device.

Patent Document 1 discloses an eccentric oscillating gear device with multiple crankshafts. This gear device includes an oscillating gear, multiple crankshafts that are positioned offset from the center of the oscillating gear in the radial direction of the oscillating gear, and a crankshaft gear that is provided on at least one of the crankshafts and receives rotation.

JP 2019-72842 A

When controlling the operation of a gear device, it is desirable to be able to detect the rotation of the rotating elements used in the gear device. However, no device has yet been proposed that incorporates any ingenuity into detecting the rotation of the rotating elements in an eccentric oscillating gear device that has multiple crankshafts.

One of the objectives of this disclosure is to provide a technology that makes it possible to detect the rotation of a rotating element in an eccentric oscillating gear device that has multiple crankshafts.

The gear device disclosed herein is an eccentric oscillating gear device that includes an oscillating gear, multiple crankshafts that are positioned at positions radially offset from the center of the oscillating gear, and a crankshaft gear that is provided on at least one of the crankshafts and to which rotation is input, and includes a rotation detector that faces the teeth of the crankshaft gear and detects the rotation of the crankshaft gear.

According to the present disclosure, it becomes possible to detect the rotation of the crankshaft gears in an eccentric oscillating gear device equipped with multiple crankshafts.

FIG. 2 is a side cross-sectional view of the gear device of the first embodiment. FIG. 2 is a schematic diagram showing a cross section taken along line AA in FIG. FIG. 3 is an enlarged view of a portion of FIG. 2 . FIG. 2 is a block diagram of a gear motor according to an embodiment. FIG. 3 is a diagram showing a state in which the carrier has been rotated from the state shown in FIG. 2 . FIG. 4 is a view of a gear device according to a second embodiment, seen from the same perspective as FIG. 3 .

The following describes the embodiments. Identical components are given the same reference numerals, and duplicate 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 according to the orientation of the reference numerals.

(First embodiment) See Figures 1 and 2. The main features of the gear device 10 relate to the rotation detector 60, which will be described later, but the peripheral structure will be described first.

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 constitutes the multi-joint arm. The robot device is, for example, an industrial robot, a service robot, etc.

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. In this embodiment, the oscillating gear 20 is the external gear 16. The external gear 16 and the internal gear 18 function as a reduction mechanism that reduces the rotation of the crankshafts 24A to 24C, which will be described later.

The gear device 10 further comprises 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 comprises a casing 28 that houses the crankshafts 24A-24C, etc., carriers 32A, 32B that support the crankshafts 24A, 24B, 24C via crank bearings 30, and an output member 34 that extracts output rotation, which is reduced in speed relative to the rotation of the crankshafts 24A-24C, from the reduction mechanism.

The oscillating gear 20 (externally toothed gear 16) is provided individually corresponding to each of the multiple eccentric bodies 40 described below, and is supported for relative rotation to the corresponding eccentric body 40 via the eccentric body bearing 36. The multiple crankshafts 24A to 24C may be arranged at offset positions relative to the center CL1 of any of the oscillating gears 20.

In this embodiment, the number of crankshafts 24A-24C is three. The crankshafts 24A-24C are spaced apart in the circumferential direction of the oscillating gear 20. The crankshafts 24A-24C pass through the oscillating gear 20 in the axial direction of the oscillating gear 20.

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

In this embodiment, the number of crankshaft gears 26A-26C is three. The crankshaft gears 26A-26C are provided individually for each of the crankshafts 24A-24C. Like the crankshafts 24A-24C, the crankshaft gears 26A-26C are also spaced apart 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.

The crankshaft gears 26A-26C are provided so as to be rotatable integrally with the crankshafts 24A-24D by means of a recess-projection fit or the like. In this embodiment, the crankshaft gears 26A-26C are fixed to the crankshafts 24A-24C using a retaining ring 42 so as not to be able to move in the axial direction.

The crankshaft gears 26A to 26C are spur gears. The crankshaft gears 26A to 26C have multiple teeth 44 on their outer periphery. 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 multiple teeth 44. Similarly, the outline of the outer periphery of the input gear 46 is shown using a pitch circle formed by its multiple teeth.

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 include a gear motor, an engine, 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 multiple crankshaft gears 26A to 26C, and the rotation of the input gear 46 is distributed to each of the multiple crankshaft gears 26A to 26C. This allows the multiple crankshaft gears 26A to 26C to rotate in the same direction at the same rotational speed. In addition, the multiple crankshafts 24A to 24C rotated by each of the multiple crankshaft gears 26A to 26C can also rotate in the same direction at the same rotational speed.

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.

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

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 relative to the first mating member 12.

The operation of the gear device 10 described above will be explained. 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.

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," "circumferential direction," and "radial direction," they refer to the axial direction, circumferential direction, and radial direction of the meshing gears 22. The circumferential direction and radial direction of the meshing gears 22 refer to the circumferential direction and radial direction of a circle centered on the central axis CL4 of the meshing gears 22.

The crankshafts 24A-24C in this embodiment include a first crankshaft 24A and a second crankshaft 24B that are 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.

The gear device 10 includes a rotation detector 60 that faces the teeth 44 of the crankshaft gears 26A and 26B in the radial direction of the crankshaft gears 26A and 26B and detects the rotation of the crankshaft gears 26A and 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 and 66B that are provided on the main surfaces 64A and 64B of the substrate 62.

The substrate 62 has a first main surface 64A and a second main surface 64B that are individually provided on both sides of the substrate 62 in the plate thickness direction. The second main surface 64B is provided on the opposite side of the substrate 62 in the plate thickness direction from the first main surface 64A. When viewed from the axial direction, the substrate 62 is arranged so that its plate 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) and extends in the radial direction. The substrate 62 is arranged at a position offset in the circumferential direction with respect to the crankshaft gears 26A, 26B.

The rotation detector 60 is fixed to the first carrier 32A, which is synchronized with the revolution component of the crankshaft gears 26A to 26C when the gear device 10 is in operation. Here, "synchronization" refers to maintaining a state in which the crankshaft gears 26A to 26C do not rotate when they do not revolve, and rotating at the same circumferential component speed as the revolution component of the crankshaft gears 26A to 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).

When viewed from the axial direction, a circle circumscribing the multiple crankshaft gears 26A-26C is defined as circumscribing circle C. The circumscribing circle C has its center at the central axis CL4 of the meshing gears 22. When viewed from the axial direction, the base plate 62 has a fixed portion 62a provided at a position that axially overlaps with the first carrier 32A, and an extending portion 62b that extends 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.

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.

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 is 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 is 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.

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 arranged to extend circumferentially from the connection position.

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 and motor 48 of the embodiment. Each block shown in the block diagrams in this specification can be realized in hardware terms by electronic components such as a computer's CPU (Central Processing Unit), circuits, mechanical devices, etc., and in software terms 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.

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, ROM, RAM, etc. The control device 82 can control the motor 48 using the output signal of the rotation detector 60. There are no particular limitations on the control method of the control device 82. 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 and 26B, and control the output of the motor 48 so that the output member 34 is at a target rotation angle.

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

The detection processing units 66A and 66B, which are composed of ICs, are provided on the main surfaces 64A and 64B of the substrate 62 by being mounted on the main surfaces 64A and 64B. 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 adhesive or the like, and the ICs constituting the detection processing units 66A and 66B may be fixed to the bias magnet 86 by adhesive 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. Alternatively, 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.

The detection element 84 incorporated in the detection processing units 66A and 66B is, for example, a magnetic resistance element that detects changes in a magnetic field. The rotation detector 60 of this embodiment is equipped with a bias magnet 86 that applies a bias magnetic field to the detection element 84. FIG. 3 shows a portion of the magnetic field lines La of the bias magnetic field. The bias magnet 86 is arranged so that different polarities (north and south poles) are aligned in the radial direction of the crankshaft gears 26A and 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 and 66B are the same, but may be opposite.

The crankshaft gears 26A, 26B are made of soft magnetic materials such as electromagnetic steel sheets and silicon iron so that they are magnetized by the bias magnetic field. The magnetic field applied to the detection element 84 changes with the rotation of the crankshaft gears 26A, 26B due to the influence of the convex and concave portions formed by the multiple teeth 44 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 a 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 explanation will be omitted here.

The detection processing units 66A and 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 and 26B. Using this output signal, the rotation state of the crankshafts 24A and 24B that rotate integrally with the crankshaft gears 26A and 26B can also be determined.

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

The processing method of the detection processing units 66A and 66B may also be an incremental method that uses the detection signal of the detection element 84 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 using the incremental method, 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, the two-phase analog signals may be AD converted and divided into pulse signals that become A-phase and B-phase signals as output signals.

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

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

The detection processing units 66A and 66B may be capable of executing each of the multiple processing methods described so far, or may be capable of executing any one of them. Regardless of which processing method is used, 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 a similar purpose.

The first detection processing unit 66A detects the rotation of the first crankshaft gear 26A using 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 using the detection element 84 and processes the detected detection signal.

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 for each detection processing unit 66A, 66B to process the detection signal using different processing methods are not particularly limited.

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 the 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.

The control device 82 is electrically connected to a power source 88 and a user interface 89. The power source 88 is used to supply power to electrical equipment (motor 48, rotation detector 60) including the control device 82. Electrical equipment other than the control device 82 is supplied with power from the power source 88 via 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.

The effects of the above gear device 10 will now be explained.

The gear device 10 of this embodiment is equipped with a rotation detector 60 that detects the rotation of the crankshaft gears 26A, 26B. Therefore, in a gear device 10 equipped with multiple crankshafts 24A to 24C, the rotation detector 60 can detect the rotation of the crankshaft gears 26A, 26B. In addition, since the rotation detector 60 is disposed in a location facing the teeth 44 of the crankshaft gears 26A, 26B, which is prone to becoming dead space, the rotation detector 60 can be incorporated into the gear device 10 while miniaturizing the gear device 10.

The rotation detector 60 includes a first detection processing unit 66A facing the first crankshaft gear 26A and a second detection processing unit 66B facing the second crankshaft gear 26B. Therefore, the first detection processing unit 66A and the second detection processing unit 66B can detect the rotation of the different crankshaft gears 26A and 26B. In addition, by providing multiple detection processing units 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. Therefore, the number of parts can be reduced compared to using a dedicated board 62 for each individual detection processing unit 66A and 66B.

The first detection processing unit 66A and the second detection processing unit 66B process the detection signal using different processing methods. This allows each detection processing unit 66A, 66B to output a different output signal indicating the rotation state of the crankshaft gears 26A, 26B.

The wiring 68 is connected to the extension 62b of the substrate 62 that extends radially outward from the circumscribed circle C. If the extension 62b is not provided on the substrate 62 and the crankshaft gears 26A to 26C revolve due to the rotation of the first carrier 32A, it is necessary to extend the wiring 68 from the substrate 62 in the axial direction opposite the first carrier 32A 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 the side member (here, the second casing member 52) that is axially opposite 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 the first carrier 32A, and it is not necessary to secure an extra axial dimension between the side member and the substrate 62.

Next, we will explain other improvements to the gear device 10.

See Figures 2 and 5. The relative rotational angle range (hereinafter referred to as the movable angle range) between the casing 28 and the carriers 32A, 32B is less than 360°. This movable angle range refers to the angle range around the central axis CL4 of the meshing gears 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 rotational angle range between the casing 28 and the carriers 32A, 32B may be mechanically limited or controlled by the control device 82.

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.

The carrier 32A can rotate 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 the 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 the reverse rotation direction Db) that is opposite to the forward rotation direction Da.

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.

The movable part 92 of the wiring 68 is positioned so as to surround the multiple 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 positioned radially outward of the circumscribed 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 that is narrower than the first circumferential range Ra when the carrier 32A is in the second angular position Pb.

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 in accordance with 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.

In this way, the wiring 68 is arranged to surround the multiple crankshaft gears 26A-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 move in response to 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.

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 can 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 the rotation of the carrier 32A. The interference prevention mechanism 100 of this embodiment is provided with a guide 102 that restricts the radially inward movement of the wiring 68 by contacting 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.

In this embodiment, the guide 102 is fixed to the carrier 32A and can rotate integrally with the carrier 32A. When viewed from the axial direction, the guide 102 is provided so as to surround the multiple crankshaft gears 26A to 26C. 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 its radially inward movement.

The length adjustment mechanism 104 in 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 uses the biasing force of the biasing member to wind up the movable part 92 of the wiring 68, thereby preventing the wiring 68 from loosening. When the carrier 32A rotates in the reverse rotation direction Db and the movable portion 92 of the wiring 68 is pulled, the length adjustment mechanism 104 can pay out the wiring 68 from the drum against the biasing force of the biasing member. This allows the length adjustment mechanism 104 to adjust the payout length of the movable portion 92 of the wiring 68.

When the carrier 32A attempts to rotate in the forward rotation direction Da, the guide 102 can limit the movement of the wiring 68 toward the crankshaft gears 26A-26C caused by 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.

When the carrier 32A attempts to rotate in the reverse rotation direction Db and the movable part 92 of the wiring 68 is 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 can be pulled out from the length adjustment mechanism 104 to increase its pulled-out length.

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

(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 that faces the detected portion 112 in the radial direction of the casing 28 (meshing gear 22).

The third detection processing unit 114 is provided at the outer peripheral 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 part 112 with a detection element (not shown) incorporated therein. The detection element of the third detection processing unit 114 and the detected part 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.

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 detected part 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.

As a result, when the first carrier 32A rotates, the second rotation detector 110 can detect the rotation of the first carrier 32A. When the casing 28 rotates, the second rotation detector 110 can also detect the rotation of the casing 28.

We will now explain variations of the above components.

Specific examples of the first mating member 12 and the second mating member 14 are not particularly limited. 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.

In the embodiment, the oscillating gear 20 of the gear device 10 is an external gear 16. Alternatively, the oscillating gear 20 may be an internal gear 18.

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 become the output member 34. Alternatively, the casing 28 may rotate relative to the carriers 32A and 32B, and the casing 28 may become the output member 34. In this case, since the carrier 32 does not rotate, measures to prevent loosening of the wiring due to the rotation of the carrier 32 are not necessary (i.e., twisting of the wiring can be avoided). In addition, the second casing member 52 may be fixed to the carrier 32A. Furthermore, the movable angle range of the casing 28 and the carriers 32A and 32B may be unlimited.

The crankshaft gears 26A-26C need only be provided on at least one of the crankshafts 24A-24C, and there is no particular limit to the number of crankshaft gears. For example, there may be a single crankshaft gear 26A-26C, or there may be two, four or more. When there is a single crankshaft gear 26A-26C, only one crankshaft 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 multiple crankshafts 24A-24C can rotate in the same direction at the same rotational speed.

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

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 a wireless transmission method is used, measures against loosening of the wiring 68 in the embodiment can be eliminated. When a wireless transmission method is used, the rotation state of the crankshaft gears 26A, 26B is obtained by the control device 82 through remote measurement using the rotation detector 60 under the control of the control device 82. When a 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.

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 necessary to use the wiring 68 arranged in the casing 28 as in the embodiment. In this case, for example, a rotation connection connector may be incorporated into 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 connects to the control device 82. The rotation connection connector becomes 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 via wiring 68 arranged inside the casing 28. Specific examples of the connector for rotational connection are not particularly limited, and for example, a slip ring mechanism combining a slip ring and a brush, a liquid metal rotary connector, etc. may be used.

In the embodiment, the rotation detector 60 is described as having a first detection processing unit 66A and a second detection processing unit 66B that face the teeth 44 of different crankshaft gears 26A and 26B. In addition, the rotation detector 60 may have only a single detection processing unit that faces the teeth of a single crankshaft gear.

The first detection processing unit 66A and the second detection processing unit 66B may process the detection signal using the same processing method.

The substrate 62 does not have to have the extension portion 62b. In this case, the wiring 68 may be connected to the fixed portion 62a of the substrate 62.

The wiring 68 does not have to be arranged to surround the multiple crankshaft gears 26A, 26B. To achieve this, for example, if the wiring 68 has a movable part 92, the movable part 92 of the wiring 68 may be provided only radially outside a single crankshaft gear.

The gear device 10 does not 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 the external wiring described above.

The specific example of the guide 102 is not particularly limited. In the embodiment, the guide 102 is described as a plate-shaped member extending in an arc shape, but it may be a cylindrical member extending in an arc shape. Also, although the guide 102 is described as being composed of a single member, it may be composed of multiple members.

Specific examples of the length adjustment mechanism 104 are not limited. The length adjustment mechanism 104 may be, for example, a U-turn mechanism that holds a part of the wiring 68 that is closer to the fixed part 90 than the movable part 92 in a U-turned state and changes the length of the U-turned part in conjunction with the change in the payout length of the movable part 92 of the wiring 68. When this is used, the length of the U-turn part can be decreased in conjunction with the increase in 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 in 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. In addition, 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.

The above embodiments and variations are merely examples. The technical ideas that abstract these should not be interpreted as being limited to the contents of the embodiments and variations. Many design changes are possible in the contents of the embodiments and variations, such as changing, adding, or deleting components. In the above embodiments, 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 not so notated. Hatching on cross sections in the drawings does not limit the material of the objects that are hatched.

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 (5)

A oscillating gear;
A plurality of crankshafts are disposed at positions offset from a 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,
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 the teeth of the second crankshaft gear. 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. A oscillating gear;
A plurality of crankshafts are disposed at positions offset from a 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. A oscillating gear;
A plurality of crankshafts are disposed at positions offset from a 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. A oscillating gear;
A plurality of crankshafts are disposed at positions offset from a 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 accompanying rotation of the carrier.

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