JP7299384B1 - Inscribed planetary gear system and robot joint system - Google Patents

Abstract

An internally joined planetary gear device and a robot joint device capable of restricting axial movement of a crankshaft while having a relatively simple configuration are provided. An internally meshing planetary gear device (1B) includes an internal gear (2), a planetary gear (3), an input side carrier (18), an output side carrier (19), and a regulating structure (9). The crankshaft 7A swings the planetary gear 3 by rotating around its axis. The input side carrier 18 and the output side carrier 19 are arranged on both sides in the axial direction along the axis of the planetary gear 3 and rotatably support the crankshaft 7A. The restricting structure 9 restricts the axial movement of the crankshaft 7A in either one of the input-side carrier 18 and the output-side carrier 19 . [Selection drawing] Fig. 17

Description

TECHNICAL FIELD The present disclosure relates generally to internally meshing planetary gear systems and joint systems for robots, and more particularly to internally meshing planetary gear systems and robot joint systems in which planetary gears having external teeth are arranged inside internal gears having internal teeth. The present invention relates to a joint device for robots.

As a related technique, an eccentric oscillating internal meshing planetary gear device called a distribution type is known (see, for example, Patent Document 1). An internally meshing planetary gear device according to a related technique includes a plurality of (for example, three) crankshafts arranged at positions offset from the axial center of an internal gear, and the crankshaft gears synchronously drive the crankshafts. By doing so, the planetary gear (external gear) is internally meshed with the internal gear while being oscillated.

The planetary gears include first planetary gears and second planetary gears. A pair of carriers are arranged on both axial sides of the first planetary gear and the second planetary gear. Each crankshaft is supported by a pair of carriers via a pair of tapered roller bearings. When the input gear rotates, the three crankshaft gears simultaneously meshing with it rotate in the same direction at the same rotational speed. Since the crankshaft is spline-connected to each crankshaft gear, the three crankshafts rotate in the same direction at the same rotational speed while being reduced to the gear ratio between the input gear and the crankshaft gear. As a result, the three first eccentric portions formed at the same position in the axial direction of the three crankshafts rotate synchronously to oscillate the first planetary gears, and at the same position in the axial direction of the three crankshafts. The three formed second eccentric portions rotate synchronously to oscillate the second planetary gear.

The first planetary gear and the second planetary gear are internally meshed with the internal gear. The internal gear has a gear body and an outer pin (pin member) that is rotatably incorporated in the gear body and that forms internal teeth of the internal gear. Here, the number of teeth of the internal gear (the number of outer pins) is slightly larger than the number of teeth of each planetary gear. Therefore, every time each planetary gear oscillates once, the first planetary gear and the second planetary gear are out of phase with respect to the internal gear in the circumferential direction of the difference in the number of teeth (rotate). It is transmitted to the pair of carriers as revolution around the axis (rotational axis) of the internal gear of the crankshaft. As a result, the pair of carriers can be rotated relative to the gear body (the casing integrated with the gear body) around the rotation axis.

JP 2016-75354 A

In the configuration of the above related art, each crankshaft is restricted from moving in the axial direction by being supported by a pair of carriers via a pair of tapered roller bearings. However, there is a problem that it is difficult to reduce the size of the device.

An object of the present disclosure is to provide an internal planetary gear device and a robot joint device that can regulate the axial movement of a crankshaft while having a relatively simple configuration.

An internally meshing planetary gear device according to an aspect of the present disclosure includes an internal gear, a planetary gear, a crankshaft, an input-side carrier and an output-side carrier, and by oscillating the planetary gear, The planetary gear is rotated relative to the internal gear. The internal gear has an annular gear body, and a plurality of outer pins that are rotatably held in a plurality of inner peripheral grooves formed on the inner peripheral surface of the gear body and constitute internal teeth. The planetary gear has external teeth that partially mesh with the internal teeth. The crankshaft oscillates the planetary gears by rotating about its axis. The input-side carrier and the output-side carrier are arranged on both sides in the axial direction along the axis of the planetary gear, and rotatably support the crankshaft. The internal meshing planetary gear system further includes a regulating structure. The restricting structure restricts movement of the crankshaft in both axial directions in only one of the input side carrier and the output side carrier.

A robot joint device according to an aspect of the present disclosure includes the internal meshing planetary gear device, a first member fixed to the gear body, and relative rotation of the planetary gear with respect to the internal gear. and a second member that rotates relative to the first member.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide an internally joined planetary gear device and a robot joint device capable of regulating axial movement of a crankshaft while having a relatively simple configuration.

FIG. 1 is a perspective view showing a schematic configuration of an actuator including an internal meshing planetary gear device according to a basic configuration. FIG. 2 is a schematic exploded perspective view of the internal meshing planetary gear device as viewed from the input side of the rotary shaft. FIG. 3 is a schematic exploded perspective view of the internal meshing planetary gear device as viewed from the output side of the rotary shaft. FIG. 4 is a schematic cross-sectional view of the internal meshing planetary gear device of the same. FIG. 5 is a cross-sectional view taken along the line A1-A1 of FIG. 4, showing the internal meshing planetary gear device of the same. FIG. 6 is a cross-sectional view taken along line B1-B1 of FIG. 4, showing the internal meshing planetary gear device of the same. 7 is a schematic cross-sectional view of an internally meshing planetary gear device according to Reference Example 1. FIG. FIG. 8 is a schematic view of the internal meshing planetary gear device as viewed from the output side of the rotating shaft. FIG. 9 is a schematic perspective view showing the configuration around the crankshaft of the internal meshing planetary gear device of the same. FIG. 10 is a schematic exploded perspective view showing the configuration around the crankshaft of the internal meshing planetary gear device of the same. FIG. 11 is a schematic perspective view showing a crankshaft of the internal meshing planetary gear device of the same. FIG. 12 is a schematic enlarged view of a region Z1 in FIG. 7, showing a main part of the internal meshing planetary gear device of the same. FIG. 13 is a schematic enlarged view of a region Z2 in FIG. 7, showing a main part of the internal meshing planetary gear device of the same. FIG. 14 is a schematic enlarged view of a region Z1 in FIG. 13, showing a main part of the internal meshing planetary gear device of the same. FIG. 15 is a schematic diagram showing a robot joint device using the internal meshing planetary gear device of the above. 16 is a schematic cross-sectional view of the internally meshing planetary gear device according to Embodiment 1. FIG. FIG. 17 is a schematic enlarged view of a region Z1 in FIG. 16, showing a main part of the internal meshing planetary gear device of the same.

(basic configuration)
(1) Overview An overview of the internal meshing planetary gear device 1 according to the basic configuration will be described below with reference to FIGS. 1 to 4. FIG. The drawings referred to in this disclosure are all schematic diagrams, and the ratio of the size and thickness of each component in the drawing does not necessarily reflect the actual dimensional ratio. For example, the tooth profile, dimensions, number of teeth, etc. of the internal teeth 21 and the external teeth 31 in FIGS. not on purpose.

An internally meshing planetary gear device 1 (hereinafter also simply referred to as a “gear device 1 ”) according to the present basic configuration is a gear device including an internal gear 2 and planetary gears 3 . In this gear device 1 , a planetary gear 3 is arranged inside an annular internal gear 2 , and the planetary gear 3 is rotated relative to the internal gear 2 by oscillating the planetary gear 3 . The internally meshing planetary gear device 1 further includes a bearing member 6 having an outer ring 62 and an inner ring 61 . The inner ring 61 is arranged inside the outer ring 62 and supported to be relatively rotatable with respect to the outer ring 62 . In particular, the gear device 1 according to the present basic configuration is an eccentric oscillation type internally meshing planetary gear device called a distributed type.

As shown in FIGS. 1 to 4, the gear device 1 according to the basic configuration includes a plurality of (three in the basic configuration) cranks arranged at positions offset from the axis (rotational axis Ax1) of the internal gear 2. It has shafts (eccentric shafts) 7A, 7B and 7C. Further, the gear device 1 includes an input shaft 500 centered on the rotation axis Ax1 arranged on the axial center (rotational axis Ax1) of the internal gear 2, and an input gear 501 integrally formed with the input shaft 500. , is equipped with Crankshaft gears 502A, 502B, 502C are spline-connected to the plurality of crankshafts 7A, 7B, 7C, respectively. These multiple (three in the basic configuration) crankshaft gears 502A, 502B, 502C are arranged so as to mesh with the input gear 501 . Therefore, in the gear device 1, when the input shaft 500 is driven, the input gear 501 synchronously drives the crankshafts 7A, 7B, and 7C, thereby causing the planetary gears 3 to oscillate.

The internal gear 2 has internal teeth 21 and is fixed to the outer ring 62 . In particular, in this basic configuration, the internal gear 2 has an annular gear body 22 and a plurality of outer pins 23 . A plurality of outer pins 23 are held on the inner peripheral surface 221 of the gear body 22 in a rotatable state, and constitute the inner teeth 21 . The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21 . That is, the planetary gear 3 is inscribed with the internal gear 2 inside the internal gear 2 , and a portion of the external teeth 31 meshes with a portion of the internal teeth 21 . In this state, when the plurality of crankshafts 7A, 7B, and 7C are driven, the planetary gear 3 swings, and the meshing position between the internal teeth 21 and the external teeth 31 moves in the circumferential direction of the internal gear 2. , relative rotation occurs between the two gears (the internal gear 2 and the planetary gear 3) according to the difference in the number of teeth between the planetary gear 3 and the internal gear 2. As shown in FIG. Here, if the internal gear 2 is fixed, the planetary gear 3 will rotate (rotate) with the relative rotation of both gears. As a result, from the planetary gear 3, a rotational output reduced at a relatively high reduction ratio is obtained in accordance with the difference in the number of teeth between the two gears.

This type of gear device 1 is used so that the rotation corresponding to the rotation component of the planetary gear 3 is taken out as the rotation of a pair of carriers 18 and 19 integrated with the inner ring 61 of the bearing member 6 . As a result, the gear device 1 functions as a gear device with a relatively high reduction ratio, with the input shaft 500 on the input side and the pair of carriers 18 and 19 on the output side. Therefore, in the gear device 1 according to this basic configuration, the pair of carriers 18 and 19 transmit the rotation corresponding to the rotation component of the planetary gear 3 to the pair of carriers 18 and 19. support. A pair of carriers 18, 19 are arranged on both sides of the planetary gear 3 in the axial direction (direction along the rotation axis Ax1), and rotatably support the crankshafts 7A, 7B, 7C.

Here, the plurality of crankshafts 7A, 7B, and 7C are inserted into the plurality of openings 33 formed in the planetary gear 3, and rotate relative to the internal gear 2 as the planetary gear 3 rotates. rotates. Each of the crankshafts 7A, 7B, 7C has an axial portion 71 and an eccentric portion 72 that is eccentric with respect to the axial portion 71. As shown in FIG. A pair of carriers 18, 19 rotatably support an axial center portion 71 of each of the crankshafts 7A, 7B, 7C. Part 72 is inserted. Therefore, the oscillation component of the planetary gear 3 , that is, the revolution component of the planetary gear 3 is absorbed by the revolution component of the eccentric portion 72 with respect to the axial center portion 71 . In other words, the eccentric portions 72 of the axial portions 71 of the crankshafts 7A, 7B, and 7C rotate so as to revolve around the axial portions 71, respectively, so that the oscillation component of the planetary gear 3 is absorbed. Therefore, the rotation (rotational component) of the planetary gear 3 excluding the oscillation component (revolution component) of the planetary gear 3 is transmitted to the pair of carriers 18, 19 by the plurality of crankshafts 7A, 7B, 7C. It will be.

Further, the gear device 1 according to this basic configuration constitutes an actuator 100 together with a drive source 101, as shown in FIG. In other words, the actuator 100 according to this basic configuration includes the gear device 1 and the drive source 101 . A drive source 101 generates a drive force for swinging the planetary gear 3 . Specifically, the drive source 101 causes the planetary gear 3 to oscillate by rotating the input shaft 500 around the rotation axis Ax1.

(2) Definition “Annular” in the present disclosure means a ring-like shape that forms a space (area) surrounded inside at least in plan view, and a perfect circle and a certain circle in plan view The shape is not limited to an annular shape, and may be, for example, an elliptical shape, a polygonal shape, or the like. Further, for example, even a shape having a bottom, such as a cup shape, is included in the "annular shape" if the peripheral wall is annular.

"Revolution" as used in the present disclosure means that an object revolves around a rotation axis other than the central axis passing through the center (center of gravity) of the object. will move along an orbit centered on Therefore, for example, when an object rotates around an eccentric axis parallel to the central axis passing through the center (center of gravity) of the object, the object revolves around the eccentric axis as the axis of rotation. . As an example, the planetary gear 3 revolves inside the internal gear 2 by oscillating around the rotation axis Ax1.

Further, in the present disclosure, one side of the rotation axis Ax1 (the left side in FIG. 4) may be referred to as the "output side" and the other side of the rotation axis Ax1 (the right side in FIG. 4) may be referred to as the "input side." In the example of FIG. 4, the input shaft 500 is rotated from the "input side" of the rotation axis Ax1, and the rotation of the pair of carriers 18, 19 is extracted from the "output side" of the rotation axis Ax1. However, the terms "input side" and "output side" are merely labels attached for explanation, and are not meant to limit the positional relationship between the input and the output as viewed from the gear device 1 .

A "rotational axis" as used in the present disclosure means a virtual axis (straight line) that is the center of rotational motion of a rotating body. That is, the rotation axis Ax1 is a virtual axis with no substance. The input shaft 500 rotates around the rotation axis Ax1.

"Internal teeth" and "external teeth" as used in the present disclosure each mean a set (group) of a plurality of "teeth" rather than a single "tooth". That is, the internal tooth 21 of the internal gear 2 is a set of a plurality of teeth arranged on the inner peripheral surface 221 of the internal gear 2 (gear body 22). Similarly, the external teeth 31 of the planetary gear 3 are a set of teeth arranged on the outer peripheral surface of the planetary gear 3 .

(3) Structure Hereinafter, the detailed structure of the internal meshing planetary gear device 1 according to the present basic structure will be described with reference to FIGS. 1 to 6. FIG.

FIG. 1 is a perspective view showing a schematic configuration of an actuator 100 including a gear device 1. FIG. FIG. 1 schematically shows the drive source 101 . FIG. 2 is a schematic exploded perspective view of the gear device 1 viewed from the input side of the rotating shaft Ax1. FIG. 3 is a schematic exploded perspective view of the gear device 1 viewed from the output side of the rotating shaft Ax1. FIG. 4 is a schematic cross-sectional view of the gear device 1. FIG. 5 is a cross-sectional view taken along the line A1-A1 of FIG. 4. FIG. 6 is a cross-sectional view taken along the line B1-B1 of FIG. 4. FIG. However, in FIGS. 5 and 6, parts other than the crankshafts 7A, 7B, and 7C are omitted from hatching even in cross sections.

(3.1) Overall Configuration As shown in FIGS. 1 to 4, the gear device 1 according to this basic configuration includes an internal gear 2, a planetary gear 3, a bearing member 6, and a plurality of crankshafts 7A and 7B. , 7C, a pair of carriers 18 and 19, and an input shaft 500. As shown in FIG. In this basic configuration, the gear device 1 further includes an input gear 501, a plurality of crankshaft gears 502A, 502B, 502C, a pair of rolling bearings 41, 42, an eccentric bearing 5, and a case 10. I have. In this basic configuration, the materials of the internal gear 2, the planetary gear 3, the plurality of crankshafts 7A, 7B, 7C, the pair of carriers 18, 19, etc., which are the components of the gear device 1, are stainless steel, cast iron, and Metals such as carbon steel, chromium molybdenum steel, phosphor bronze or aluminum bronze, or light metals such as aluminum or titanium. The metals (including light metals) referred to here include metals subjected to surface treatment such as nitriding.

Further, in this basic configuration, as an example of the gear device 1, an internal planetary gear device using a trochoidal tooth profile is exemplified. That is, the gear device 1 according to this basic configuration includes the internal planetary gear 3 having a trochoidal curved tooth profile.

Further, in this basic configuration, as an example, the gear device 1 is used in a state where the gear body 22 of the internal gear 2 is fixed to a fixed member such as the case 10 together with the outer ring 62 of the bearing member 6 . As a result, as the internal gear 2 and the planetary gear 3 rotate relative to each other, the planetary gear 3 rotates relative to the fixed member (case 10, etc.).

Furthermore, in the present basic configuration, when the gear device 1 is used for the actuator 100 , a rotational force as an input is applied to the input shaft 500 so that the pair of carriers 18 , 19 integrated with the inner ring 61 of the bearing member 6 rotates. Rotational force is taken out as an output. That is, the gear device 1 operates with the rotation of the input shaft 500 as input rotation and the rotation of the pair of carriers 18 and 19 integrated with the inner ring 61 as output rotation. As a result, in the gear device 1, an output rotation that is reduced at a relatively high speed reduction ratio is obtained with respect to the input rotation.

The drive source 101 is a power generation source such as a motor (electric motor). Power generated by the drive source 101 is transmitted to the input shaft 500 in the gear device 1 . Specifically, the drive source 101 is connected to the input shaft 500 , and the power generated by the drive source 101 is transmitted to the input shaft 500 . This allows the drive source 101 to rotate the input shaft 500 .

Furthermore, in the gear device 1 according to this basic configuration, as shown in FIG. 4, the input-side rotation axis Ax1 and the output-side rotation axis Ax1 are on the same straight line. In other words, the input-side rotation axis Ax1 and the output-side rotation axis Ax1 are coaxial. Here, the input-side rotation axis Ax1 is the rotation center of the input shaft 500 to which the input rotation is applied, and the output-side rotation axis Ax1 is the inner ring 61 (and the pair of carriers 18 and 19) that generate the output rotation. is the center of rotation. In other words, in the gear device 1, the output rotation is coaxially reduced with respect to the input rotation with a relatively high reduction ratio.

The internal gear 2 is an annular component having internal teeth 21, as shown in FIGS. In this basic configuration, the internal gear 2 has an annular shape in which at least the inner peripheral surface is a perfect circle in plan view. Internal teeth 21 are formed on the inner peripheral surface of the annular internal gear 2 along the circumferential direction of the internal gear 2 . The plurality of teeth forming the internal gear 21 are all of the same shape, and are provided at equal pitches over the entire circumferential direction of the internal peripheral surface of the internal gear 2 . That is, the pitch circle of the internal teeth 21 is a perfect circle in plan view. The center of the pitch circle of the internal teeth 21 is on the rotation axis Ax1. Moreover, the internal gear 2 has a predetermined thickness in the direction of the rotation axis Ax1. All tooth traces of the internal teeth 21 are parallel to the rotation axis Ax1. The dimension of the internal tooth 21 in the tooth trace direction is slightly smaller than the thickness direction of the internal gear 2 .

Here, the internal gear 2 has an annular (annular) gear main body 22 and a plurality of outer pins 23, as described above. A plurality of outer pins 23 are held on the inner peripheral surface 221 of the gear body 22 in a rotatable state, and constitute the inner teeth 21 . In other words, the plurality of outer pins 23 function as a plurality of teeth forming the inner teeth 21 respectively. Specifically, as shown in FIG. 2, a plurality of inner peripheral grooves 223 are formed on the inner peripheral surface 221 of the gear body 22 over the entire circumferential area. The plurality of inner peripheral grooves 223 all have the same shape and are provided at equal pitches. The plurality of inner peripheral grooves 223 are all parallel to the rotation axis Ax1 and are formed over the entire length of the gear body 22 in the thickness direction. The plurality of outer pins 23 are combined with the gear body 22 so as to fit in the plurality of inner peripheral grooves 223 . Each of the plurality of outer pins 23 is held in an inner peripheral groove 223 in a rotatable state. Further, the gear body 22 is fixed to the case 10 (together with the outer ring 62). Further, the gear body 22 is formed with a plurality of fixing holes 222 (see FIG. 5) for fixing.

The planetary gear 3 is an annular component having external teeth 31, as shown in FIGS. In this basic configuration, the planetary gear 3 has an annular shape with at least an outer peripheral surface that is a perfect circle in a plan view. External teeth 31 are formed along the circumferential direction of the planetary gear 3 on the outer peripheral surface of the annular planetary gear 3 . The plurality of teeth forming the external teeth 31 are all of the same shape, and are provided at equal pitches over the entire peripheral surface of the planetary gear 3 in the circumferential direction. That is, the pitch circle of the external teeth 31 is a perfect circle in plan view. Also, the planetary gear 3 has a predetermined thickness in the direction of the rotation axis Ax1. Each of the external teeth 31 is formed over the entire length of the planetary gear 3 in the thickness direction. All of the tooth traces of the external teeth 31 are parallel to the rotation axis Ax1. In the planetary gear 3, unlike the internal gear 2, the external teeth 31 are integrally formed with the main body of the planetary gear 3 by one metal member.

Further, the gear device 1 according to this basic configuration includes a plurality of planetary gears 3 . Specifically, the gear device 1 includes two planetary gears 3 , a first planetary gear 301 and a second planetary gear 302 . The two planetary gears 3 are arranged to face each other in a direction parallel to the rotation axis Ax1. That is, the planetary gear 3 includes a first planetary gear 301 and a second planetary gear 302 arranged in a direction (axial direction) parallel to the rotation axis Ax1. The shape itself of the first planetary gear 301 and the second planetary gear 302 is common.

These two planetary gears 3 (first planetary gear 301 and second planetary gear 302) are arranged with a phase difference of 180 degrees around the rotation axis Ax1. In the example of FIG. 4, of the first planetary gear 301 and the second planetary gear 302, the center of the first planetary gear 301 located on the input side (right side of FIG. 4) of the rotation axis Ax1 (the pitch circle of the external teeth 31) The center) C1 is shifted (biased) upward in the figure with respect to the rotation axis Ax1. On the other hand, the center (the center of the pitch circle of the external teeth 31) C2 of the second planetary gear 302 located on the output side (left side in FIG. 4) of the rotation axis Ax1 is shifted downward in the figure with respect to the rotation axis Ax1 ( biased). Here, the distance ΔL1 between the rotation axis Ax1 and the center C1 is the eccentricity of the first planetary gear 301 with respect to the rotation axis Ax1, and the distance ΔL2 between the rotation axis Ax1 and the center C2 is the eccentricity with respect to the rotation axis Ax1. 2 becomes the amount of eccentricity of the planetary gear 302 . By arranging the plurality of planetary gears 3 evenly in the circumferential direction about the rotation axis Ax1 in this manner, it is possible to balance the weight and load among the plurality of planetary gears 3. .

The centers C1 and C2 of the first planetary gear 301 and the second planetary gear 302 are located 180 degrees rotationally symmetrical with respect to the rotation axis Ax1. In this basic configuration, the eccentricity ΔL1 and the eccentricity ΔL2 are opposite in direction when viewed from the rotation axis Ax1, but have the same absolute value.

More specifically, each of the crankshafts 7A, 7B, 7C has two eccentric portions 72 with respect to one shaft center portion 71, respectively. The amount of eccentricity ΔL0 (see FIGS. 5 and 6) of the center C0 of these two eccentric portions 72 from the center (axis Ax2) of the shaft center portion 71 is the first planetary gear 301 and the second planetary gear 301 with respect to the rotation axis Ax1, respectively. It is the same as the eccentricity amounts ΔL1 and ΔL2 of the gear 302 . The shape itself of the plurality of crankshafts 7A, 7B, 7C is common. A plurality of crankshaft gears 502A, 502B, and 502C also have the same shape.

A pair of carriers 18 and 19 are arranged on both sides of the first planetary gear 301 and the second planetary gear 302 in a direction (axial direction) parallel to the rotation axis Ax1. When distinguishing the pair of carriers 18 and 19 from each other, the carrier 18 located on the input side (the right side in FIG. 4) of the rotation axis Ax1 is called the "input side carrier 18", and the output side (the right side in FIG. 4) of the rotation axis Ax1. Then, the carrier 19 positioned on the left side) is called an "output side carrier 19". Both ends of the crankshafts 7A, 7B, 7C are held by a pair of carriers 18, 19 via rolling bearings 41, 42, respectively. That is, the crankshafts 7A, 7B, and 7C are held by the input side carrier 18 and the output side carrier 19 in a rotatable state on both sides of the planetary gear 3 in the direction (axial direction) parallel to the rotation axis Ax1. ing.

An eccentric body bearing 5 is attached to the eccentric portion 72 of each of the crankshafts 7A, 7B, 7C. Each of the first planetary gear 301 and the second planetary gear 302 is formed with three openings 33 corresponding to the three crankshafts 7A, 7B, 7C. Each opening 33 accommodates the eccentric bearing 5 . In other words, the eccentric bearings 5 are attached to the first planetary gear 301 and the second planetary gear 302, respectively, and the crankshafts 7A, 7B, and 7C are inserted into the eccentric bearings 5 so that the eccentric bearings 5 And each crankshaft 7A, 7B, 7C is combined with the planetary gear 3. When the planetary gears 3 are combined with the eccentric bearings 5 and the crankshafts 7A, 7B, 7C and the respective crankshafts 7A, 7B, 7C rotate, the planetary gears 3 oscillate about the rotation axis Ax1.

According to the configuration described above, a rotational force as an input is applied to the input shaft 500, and the input shaft 500 rotates about the rotation axis Ax1. , 7B and 7C. That is, when the input gear 501 rotates, the three crankshaft gears 502A, 502B, 502C meshing with the input gear 501 simultaneously rotate in the same direction at the same rotational speed. Since the crankshaft gears 502A, 502B, 502C are spline-connected to the crankshafts 7A, 7B, 7C, the three crankshafts 7A, 7B, 7C are connected to the input gear 501 and the crankshaft gears 502A, 502B, 502C. It rotates in the same direction at the same rotational speed while being reduced by the gear ratio. As a result, the three eccentric portions 72 formed at the same position on the input side of the rotation axis Ax1 of the three crankshafts 7A, 7B, and 7C rotate synchronously, causing the first planetary gear 301 to oscillate. Furthermore, the three eccentric portions 72 formed at the same position on the output side of the rotation axis Ax1 of the three crankshafts 7A, 7B, and 7C rotate synchronously, causing the second planetary gear 302 to oscillate.

5 and 6 show the states of the first planetary gear 301 and the second planetary gear 302 at a certain time. 5 is a cross-sectional view taken along the line A1-A1 of FIG. 4 and shows the first planetary gear 301. FIG. FIG. 6 is a cross-sectional view taken along line B1-B1 of FIG. 4 and shows the second planetary gear 302. As shown in FIG. As shown in FIGS. 5 and 6, the centers C1 and C2 of the first planetary gear 301 and the second planetary gear 302 are located substantially 180 degrees rotationally symmetrical with respect to the rotation axis Ax1. In this basic configuration, the eccentricity ΔL1 and the eccentricity ΔL2 are opposite in direction when viewed from the rotation axis Ax1, but their absolute values are substantially the same (both are the eccentricity ΔL0). According to the above-described configuration, the first planetary gear 301 and the second planetary gear 302 have a phase difference of approximately 180 degrees around the rotation axis Ax1 by rotating (rotating) the shaft center portion 71 around the axis Ax2. , rotates (eccentrically) around the rotation axis Ax1. By arranging the plurality of planetary gears 3 substantially evenly in the circumferential direction around the rotation axis Ax1, it is possible to balance the weight and load among the plurality of planetary gears 3 .

The planetary gears 3 (the first planetary gear 301 and the second planetary gear 302 ) configured in this manner are arranged inside the internal gear 2 . In a plan view, the planetary gear 3 is formed one size smaller than the internal gear 2, and the planetary gear 3 can oscillate inside the internal gear 2 while being combined with the internal gear 2. Become. Here, external teeth 31 are formed on the outer peripheral surface of the planetary gear 3 and internal teeth 21 are formed on the inner peripheral surface of the internal gear 2 . Therefore, when the planetary gear 3 is arranged inside the internal gear 2, the external teeth 31 and the internal teeth 21 face each other.

Furthermore, the pitch circle of the external teeth 31 is one size smaller than the pitch circle of the internal teeth 21 . In the state in which the first planetary gear 301 is inscribed in the internal gear 2, the center C1 of the pitch circle of the external teeth 31 of the first planetary gear 301 is shifted from the center of the pitch circle of the internal teeth 21 (rotational axis Ax1). It is located at a position shifted by a distance ΔL1. Similarly, when the second planetary gear 302 is inscribed in the internal gear 2, the center C2 of the pitch circle of the external teeth 31 of the second planetary gear 302 is the center of the pitch circle of the internal teeth 21 (rotational axis Ax1). It is located at a position shifted by a distance ΔL2 from .

Therefore, in both the first planetary gear 301 and the second planetary gear 302, the external teeth 31 and the internal teeth 21 are at least partially opposed to each other with a gap therebetween. If the difference in the number of teeth of is "2" or more, the entire circumferential direction will not mesh with each other. However, since the planetary gear 3 oscillates (revolves) around the rotation axis Ax1 inside the internal gear 2, the external teeth 31 and the internal teeth 21 partially mesh with each other. In other words, the planetary gears 3 (the first planetary gear 301 and the second planetary gear 302) oscillate about the rotation axis Ax1, and as shown in FIGS. Some of the teeth mesh with some of the multiple teeth forming the internal teeth 21 . As a result, in the gear device 1 , it is possible to mesh a portion of the external teeth 31 with a portion of the internal teeth 21 .

Here, the number of teeth of the internal teeth 21 of the internal gear 2 is greater than the number of teeth of the external teeth 31 of the planetary gear 3 by N (N is a positive integer). In this basic configuration, as an example, N is "2", and the number of teeth (of the external teeth 31) of the planetary gear 3 is "2" less than the number of teeth (of the internal teeth 21) of the internal gear 2. The difference in the number of teeth between the planetary gear 3 and the internal gear 2 defines the reduction ratio of the output rotation to the input rotation in the gear device 1 .

Further, in this basic configuration, as an example, the combined thickness of the first planetary gear 301 and the second planetary gear 302 is smaller than the thickness of the gear body 22 in the internal gear 2 . Furthermore, the dimension in the tooth trace direction (parallel to the rotation axis Ax1) of the external teeth 31 combined with the first planetary gear 301 and the second planetary gear 302 is direction). In other words, in the direction parallel to the rotation axis Ax1, the external teeth 31 of the first planetary gear 301 and the second planetary gear 302 fit within the range of the tooth traces of the internal teeth 21 .

Here, the first planetary gear 301 and the second planetary gear 302 are internally meshed with the internal gear 2 respectively. Therefore, every time the first planetary gear 301 and the second planetary gear 302 oscillate once, the first planetary gear 301 and the second planetary gear 302 move relative to the internal gear 2 (internal teeth 21 and external teeth 31 ) occurs in the circumferential direction due to the difference in the number of teeth, and the rotor rotates. This rotation is transmitted to the pair of carriers 18, 19 as revolution around the axis (rotational axis Ax1) of the internal gear 2 of each of the crankshafts 7A, 7B, 7C. As a result, the pair of carriers 18 and 19 can be rotated relative to the gear body (the case 10 integrated with it) about the rotation axis Ax1.

In short, the gear device 1 according to this basic configuration causes the planetary gears 3 to oscillate with the plurality of crankshafts 7A, 7B, and 7C arranged at positions offset from the rotation axis Ax1, and utilizes the oscillating motion of the planetary gears 3. to obtain the rotation output. That is, in the gear device 1, when the planetary gear 3 oscillates and the meshing position between the internal tooth 21 and the external tooth 31 moves in the circumferential direction of the internal gear 2, the planetary gear 3 and the internal gear 2 move. Relative rotation occurs between the two gears (the internal gear 2 and the planetary gear 3) according to the difference in the number of teeth. Here, if the internal gear 2 is fixed, the planetary gear 3 will rotate (rotate) with the relative rotation of both gears. As a result, from the planetary gear 3, a rotational output reduced at a relatively high reduction ratio is obtained in accordance with the difference in the number of teeth between the two gears.

The bearing member 6 has an outer ring 62 and an inner ring 61 and is a part for outputting the output of the gear device 1 as rotation of the inner ring 61 with respect to the outer ring 62 . The bearing member 6 has a plurality of rolling elements 63 (see FIG. 4) in addition to the outer ring 62 and the inner ring 61 . Both the outer ring 62 and the inner ring 61 are annular parts. Both the outer ring 62 and the inner ring 61 have annular shapes that are perfect circles in a plan view. The inner ring 61 is one size smaller than the outer ring 62 and is arranged inside the outer ring 62 . Here, since the inner diameter of the outer ring 62 is larger than the outer diameter of the inner ring 61 , a gap is generated between the inner peripheral surface of the outer ring 62 and the outer peripheral surface of the inner ring 61 .

A plurality of rolling elements 63 are arranged in a gap between the outer ring 62 and the inner ring 61 . A plurality of rolling elements 63 are arranged side by side in the circumferential direction of the outer ring 62 . The plurality of rolling elements 63 are all metal parts having the same shape, and are provided at equal pitches over the entire circumference of the outer ring 62 .

More specifically, in the gear device 1 according to this basic configuration, the bearing member 6 includes a first bearing member 601 and a second bearing member 602 . The first bearing member 601 and the second bearing member 602 are each composed of an angular contact ball bearing. Specifically, as shown in FIG. 4, a first bearing member 601 is arranged on the input side (right side in FIG. 4) of the rotation axis Ax1 as seen from the planetary gears 3, and the rotation axis Ax1 as seen from the planetary gears 3. A second bearing member 602 is arranged on the output side of (left side in FIG. 4). The bearing member 6 receives a load in the radial direction, a load in the thrust direction (direction along the rotation axis Ax1), and a bending force (bending moment load) with respect to the rotation axis Ax1 at the first bearing member 601 and the second bearing member 602. It is constructed to withstand both.

Here, the first bearing member 601 and the second bearing member 602 are arranged on both sides of the planetary gear 3 in the direction (axial direction) parallel to the rotation axis Ax1 and in opposite directions to each other in the direction parallel to the rotation axis Ax1. be done. That is, the bearing member 6 is a "combined angular contact ball bearing" in which a plurality of (here, two) angular contact ball bearings are combined. Here, as an example, the first bearing member 601 and the second bearing member 602 are of a “back-to-back combination type” in which the respective inner rings 61 receive a load in the thrust direction (direction along the rotation axis Ax1) toward each other. Furthermore, in the gear device 1, the first bearing member 601 and the second bearing member 602 are combined in a state in which an appropriate preload is applied to the inner ring 61 by tightening the inner rings 61 in a direction to bring them closer together.

In addition, in the gear device 1 according to the basic configuration, the input-side carrier 18 and the output-side carrier 19 are arranged on both sides of the planetary gear 3 in the direction parallel to the rotation axis Ax1, and the carrier hole 34 of the planetary gear 3 ( 4) are connected to each other. Specifically, as shown in FIG. 4, an input-side carrier 18 is arranged on the input side (right side in FIG. 4) of the rotation axis Ax1 as viewed from the planetary gear 3, and the input side carrier 18 is arranged on the input side of the rotation axis Ax1 as viewed from the planetary gear 3. An output-side carrier 19 is arranged on the output side (left side in FIG. 4). The inner ring 61 of the bearing member 6 (of each of the first bearing member 601 and the second bearing member 602) is fixed with respect to the input side carrier 18 and the output side carrier 19. As shown in FIG. In this basic configuration, as an example, the inner ring of the first bearing member 601 is seamlessly integrated with the input side carrier 18 . Similarly, the inner ring of the second bearing member 602 is seamlessly integrated with the output side carrier 19 .

The output-side carrier 19 has a plurality (three as an example) of carrier pins 191 (see FIG. 2) projecting from one surface of the output-side carrier 19 toward the input side of the rotation axis Ax1. These plurality of carrier pins 191 pass through a plurality (three as an example) of carrier holes 34 formed in the planetary gear 3, and their tips are attached to the input side carrier 18 by carrier bolts 192 (see FIG. 7). is fixed by Here, a gap is secured between the carrier pin 191 and the inner peripheral surface of the carrier hole 34, and the carrier pin 191 can move within the carrier hole 34, that is, move relatively to the center of the carrier hole 34. It is possible. As a result, the carrier pin 191 does not come into contact with the inner peripheral surface of the carrier hole 34 when the planetary gear 3 swings.

With the above configuration, the gear device 1 is used so that the rotation corresponding to the rotation component of the planetary gear 3 is extracted as the rotation of the input side carrier 18 and the output side carrier 19 integrated with the inner ring 61 of the bearing member 6 . That is, in this basic configuration, relative rotation between the planetary gear 3 and the internal gear 2 is taken out from the input side carrier 18 and the output side carrier 19 . In this basic configuration, as an example, the gear device 1 is used in a state where the outer ring 62 (see FIG. 4) of the bearing member 6 is fixed to the case 10 which is a fixed member. That is, the planetary gear 3 is connected to the input-side carrier 18 and the output-side carrier 19, which are rotating members, by a plurality of crankshafts 7A, 7B, and 7C, and the gear body 22 is fixed to the fixed member. Relative rotation with the internal gear 2 is taken out from the rotating members (input side carrier 18 and output side carrier 19). In other words, in this basic configuration, when the planetary gear 3 rotates relative to the gear body 22, the rotational forces of the input side carrier 18 and the output side carrier 19 are taken out as an output.

Furthermore, in this basic configuration, the case 10 is seamlessly integrated with the gear body 22 of the internal gear 2 . That is, in the direction parallel to the rotation axis Ax1, the gear body 22, which is a fixed member, and the case 10 are provided seamlessly and continuously.

More specifically, the case 10 is cylindrical and constitutes the outer shell of the gear device 1 . In this basic configuration, the central axis of the cylindrical case 10 is configured to coincide with the rotation axis Ax1. That is, at least the outer peripheral surface of the case 10 forms a perfect circle centered on the rotation axis Ax1 in a plan view (viewed from one axial direction). The case 10 is formed in a cylindrical shape with both axial end faces open. Here, the gear body 22 of the internal gear 2 is seamlessly integrated with the case 10, and the case 10 and the gear body 22 are treated as one component. Therefore, the inner peripheral surface of the case 10 includes the inner peripheral surface 221 of the gear body 22 . Furthermore, an outer ring 62 of the bearing member 6 is fixed to the case 10 . That is, the outer ring 62 of the first bearing member 601 is fitted and fixed to the input side (right side in FIG. 4) of the rotating shaft Ax1 as viewed from the gear body 22 on the inner peripheral surface of the case 10 . On the other hand, the outer ring 62 of the second bearing member 602 is fitted and fixed on the inner peripheral surface of the case 10 on the output side (left side in FIG. 4) of the rotating shaft Ax1 when viewed from the gear body 22 .

Further, the input side (right side in FIG. 4) end face of the rotation axis Ax1 in the case 10 is closed by the input side carrier 18, and the output side (left side in FIG. 4) end face of the rotation axis Ax1 in the case 10 is the output side. It is closed by carrier 19 . Therefore, as shown in FIG. 4, in the space surrounded by the case 10, the input side carrier 18 and the output side carrier 19, the planetary gears 3 (the first planetary gear 301 and the second planetary gear 302), the plurality of outer pins 23 and components such as the eccentric bearing 5 are accommodated.

Each of the plurality of (three in the basic configuration) crankshafts 7A, 7B, and 7C has an axial center portion 71 and two eccentric portions 72 . The axial center portion 71 has a cylindrical shape in which at least the outer peripheral surface is a perfect circle in a plan view. An axis Ax2, which is the center of the axis portion 71, is parallel to the rotation axis Ax1. The axes Ax2 of the plurality of crankshafts 7A, 7B, and 7C are arranged at regular intervals in the circumferential direction on a virtual circle centered on the rotation axis Ax1. Each eccentric portion 72 has a disc shape with at least an outer peripheral surface that is a perfect circle in a plan view. The center (central axis) C0 of each eccentric portion 72 is parallel to the rotation axis Ax1 and arranged at a position radially displaced from the rotation axis Ax1. Here, the distance ΔL0 (see FIGS. 5 and 6) between the axis Ax2 and the center C0 is the amount of eccentricity of the eccentric portion 72 with respect to the axial portion 71 . The eccentric portion 72 has a flange shape that protrudes from the outer peripheral surface of the shaft center portion 71 over the entire circumference at the central portion in the longitudinal direction (axial direction) of the shaft center portion 71 . According to the above-described configuration, the eccentric portions 72 of the crankshafts 7A, 7B, and 7C perform eccentric motion as the axial portions 71 rotate (rotate) about the axial center Ax2.

In this basic configuration, the axial center portion 71 and the two eccentric portions 72 are integrally formed of one metal member, thereby realizing seamless crankshafts 7A, 7B and 7C. The crankshafts 7A, 7B, 7C having such a shape are combined with the planetary gear 3 together with the eccentric bearing 5. As shown in FIG. Therefore, when the eccentric bearings 5 and the crankshafts 7A, 7B, 7C are combined with the planetary gears 3 and the crankshafts 7A, 7B, 7C rotate, the planetary gears 3 oscillate about the rotation axis Ax1.

The eccentric body bearing 5 has a plurality of rolling elements 51 (see FIG. 4), absorbs the rotation component of the rotation of the crankshafts 7A, 7B, 7C and removes the rotation component of the crankshafts 7A, 7B, 7C. It is a part for transmitting only the rotation of the crankshafts 7A, 7B, 7C, that is, the swing component (orbital component) of the crankshafts 7A, 7B, 7C to the planetary gear 3. The plurality of rolling elements 51 are arranged between the outer peripheral surface of the eccentric portion 72 of each crankshaft 7A, 7B, 7C and the inner peripheral surface of each opening 33 of the planetary gear 3 . That is, the eccentric portions 72 of the crankshafts 7A, 7B, and 7C function as inner rings of the eccentric bearings 5, and the inner peripheral surfaces of the openings 33 of the planetary gears 3 function as outer rings of the eccentric bearings 5.

With the eccentric bearing 5 and the plurality of crankshafts 7A, 7B, and 7C combined with the planetary gear 3, when the crankshafts 7A, 7B, and 7C rotate, the eccentric bearing 5 rotates around the axis Ax2 ( eccentric motion). At this time, the rotation components of the crankshafts 7A, 7B, 7C are absorbed by the eccentric bearings 5. FIG. Therefore, the planetary gear 3 receives rotation of the crankshafts 7A, 7B, and 7C excluding the rotation components of the crankshafts 7A, 7B, and 7C by the eccentric bearing 5, that is, the swing components of the crankshafts 7A, 7B, and 7C ( revolution component) will be transmitted. Therefore, when the crankshafts 7A, 7B, and 7C rotate while the planetary gears 3 are combined with the eccentric bearings 5 and the crankshafts 7A, 7B, and 7C, the planetary gears 3 oscillate about the rotation axis Ax1.

In the gear device 1 configured as described above, a rotational force as an input is applied to the input shaft 500, and the input shaft 500 rotates about the rotation axis Ax1, causing the planetary gears 3 to oscillate about the rotation axis Ax1. (revolve). At this time, the planetary gear 3 is inscribed with the internal gear 2 inside the internal gear 2 and oscillates with a portion of the external teeth 31 meshing with a portion of the internal teeth 21 . 21 and the external teeth 31 move in the circumferential direction of the internal gear 2 . As a result, relative rotation occurs between the two gears (the internal gear 2 and the planetary gear 3) according to the difference in the number of teeth between the planetary gear 3 and the internal gear 2. The rotation (rotational component) of the planetary gear 3 excluding the oscillation component (revolution component) of the planetary gear 3 is transmitted to the pair of carriers 18 and 19 by a plurality of crankshafts 7A, 7B, and 7C. . As a result, from the pair of carriers 18 and 19, rotational output reduced at a relatively high speed reduction ratio is obtained in accordance with the difference in the number of teeth between the two gears.

By the way, in the gear device 1 according to this basic configuration, as described above, the difference in the number of teeth between the internal gear 2 and the planetary gear 3 defines the reduction ratio of the output rotation to the input rotation in the gear device 1. become. That is, when the number of teeth of the internal gear 2 is "V1" and the number of teeth of the planetary gear 3 is "V2", the reduction ratio R1 is expressed by the following equation 1.

R1=V2/(V1-V2) (Formula 1)
In short, the smaller the tooth number difference (V1-V2) between the internal gear 2 and the planetary gear 3, the larger the reduction ratio R1. As an example, the number of teeth V1 of the internal gear 2 is "72", the number of teeth V2 of the planetary gear 3 is "70", and the difference between the number of teeth (V1-V2) is "2". The speed reduction ratio R1 becomes "35". In this case, when viewed from the input side of the rotation axis Ax1, each crankshaft 7A, 7B, 7C rotates clockwise around the axis Ax2 of the axis portion 71 (see FIGS. 5 and 6) once (360 degrees). When rotated, the pair of carriers 18 and 19 rotates counterclockwise about the rotation axis Ax1 by the number of teeth difference of "2" (that is, approximately 10.3 degrees).

According to the gear device 1 according to this basic configuration, such a high reduction ratio R1 can be realized by the combination of the internal gear 2 and the planetary gears 3 . Furthermore, between the input gear 501 and the plurality of crankshaft gears 502A, 502B, 502C, it is possible to achieve an appropriate reduction ratio according to the number of teeth of the input gear 501 and the crankshaft gears 502A, 502B, 502C. . As a result, the gear device 1 as a whole can achieve a high speed reduction ratio.

Further, the gear device 1 may include at least the internal gear 2, the planetary gears 3, the crankshafts 7A, 7B, 7C, and the pair of carriers 18, 19. For example, as shown in FIG. As shown, the spacer 11 may be further provided. The spacer 11 is arranged between the pair of planetary gears 3 (first planetary gear 301 and second planetary gear 302) in a direction (axial direction) parallel to the rotation axis Ax1.

(Reference example 1)
As shown in FIGS. 7 to 14, the internal meshing planetary gear device 1A (hereinafter also simply referred to as the "gear device 1A") according to the present reference example is basically configured mainly around crankshafts 7A, 7B, and 7C. It is different from the gear device 1 according to the configuration. Hereinafter, the same reference numerals are given to the same configurations as the basic configuration, and the description thereof will be omitted as appropriate. FIG. 7 is a schematic cross-sectional view of the gear device 1A. FIG. 8 is a schematic diagram of the gear device 1A viewed from the output side of the rotating shaft Ax1. FIG. 9 is a schematic perspective view of peripheral members of one crankshaft 7A. FIG. 10 is a schematic exploded perspective view of peripheral members of one crankshaft 7A. FIG. 11 is a schematic perspective view of one crankshaft 7A. FIG. 12 is an enlarged view of area Z1 in FIG. FIG. 13 is an enlarged view of area Z2 in FIG. FIG. 14 is an enlarged view of area Z1 in FIG.

As shown in FIG. 7, the gear device 1A according to this reference example further includes a plurality of oil seals 121, 122 and the like. The oil seal 121 closes the gap between the case 10 and the outer peripheral surface of the output carrier 19 . The oil seal 122 closes a central hole 193 formed in the central portion of the output side carrier 19 . A space sealed by the plurality of oil seals 121, 122 and the like forms a lubricant holding space 17. As shown in FIG. Lubricant holding space 17 includes a space between inner ring 61 and outer ring 62 of bearing member 6 . Furthermore, the plurality of outer pins 23, the planetary gear 3, the pair of rolling bearings 41 and 42, the eccentric body bearing 5, and the like are accommodated in the lubricant holding space 17. As shown in FIG.

A lubricant is injected into the lubricant holding space 17 . The lubricant is liquid and can flow within the lubricant holding space 17 . Therefore, when the gear device 1 is used, for example, the lubricant enters the meshing portions between the internal teeth 21 formed by the plurality of external pins 23 and the external teeth 31 of the planetary gears 3 . "Liquid" as used in the present disclosure includes liquid or gel substances. The term "gel state" as used herein means a state having properties intermediate between those of a liquid and a solid, and includes a state of colloid consisting of two phases, a liquid phase and a solid phase. For example, there is a state called gel or sol, such as an emulsion in which the dispersion medium is a liquid phase and the dispersoid is a liquid phase, or a suspension in which the dispersoid is a solid phase. Included in "gel-like". The state in which the dispersion medium is a solid phase and the dispersoid is a liquid phase is also included in the “gel state”. As an example in this basic configuration, the lubricant is liquid lubricating oil (oil).

The gear device 1A according to this reference example further includes a pair of covers 13 and 14 attached to both sides of the pair of carriers 18 and 19 in the axial direction. When distinguishing the pair of covers 13 and 14 from each other, the cover 13 positioned on the input side (the right side in FIG. 7) of the rotation axis Ax1 is called the "input side cover 13", and the cover 13 on the output side (the right side in FIG. 7) of the rotation axis Ax1. The cover 14 located on the left side) is called an "output side cover 14". In this reference example, the material of the pair of covers 13 and 14 is a metal such as stainless steel, cast iron, carbon steel for machine structural use, or chromium molybdenum steel, or a heat-treated metal.

The input side cover 13 is formed in a disc shape centered on the rotation axis Ax1. Here, at least the outer peripheral surface of the input side cover 13 forms a perfect circle centered on the rotation axis Ax1 in a plan view (viewed from one side in the axial direction). The outer diameter of the input side cover 13 is one size smaller than the outer diameter of the input side carrier 18 . The input side cover 13 is attached to the input side carrier 18 from the outside, that is, from the side opposite to the planetary gear 3 when viewed from the input side carrier 18 (the right side in FIG. 7).

The output side cover 14 is formed in a disc shape centered on the rotation axis Ax1. Here, at least the outer peripheral surface of the output side cover 14 forms a perfect circle centered on the rotation axis Ax1 in a plan view (viewed from one side in the axial direction). The outer diameter of the output side cover 14 is one size smaller than the outer diameter of the output side carrier 19 . The output side cover 14 is attached to the output side carrier 19 from the outside, that is, from the side opposite to the planetary gear 3 when viewed from the output side carrier 19 (the left side in FIG. 7).

Here, the pair of covers 13 and 14 are detachably attached to the pair of carriers 18 and 19 . That is, the input side cover 13 is detachably attached to the input side carrier 18 , and the output side cover 14 is detachably attached to the output side carrier 19 . In this reference example, as an example, each cover 13, 14 is attached to each carrier 18, 19 by a plurality of fixing bolts 142 (see FIG. 8). Therefore, each cover 13 and 14 can be removed from each carrier 18 and 19 by removing a plurality of fixing bolts 142 .

Here, in the output side cover 14 of the pair of covers 13 and 14, as shown in FIG. A hole 141 is provided. That is, the output-side carrier 19 is provided with a plurality of mounting holes 194 (female threads) for fixing the mating member. Therefore, in the output side cover 14 attached to the outside of the output side carrier 19 as well, a plurality of through holes 141 are formed at positions corresponding to the plurality of mounting holes 194 . In particular, when high torque is transmitted from the output-side carrier 19 to the mating member, the number of mounting holes 194 and through holes 141 increases. Also, the arrangement and number of the mounting holes 194 and the through holes 141 must be matched with the mating member.

On the other hand, shaft holes 131 (see FIG. 7) through which the crankshafts 7A, 7B, and 7C pass are provided only in the input side cover 13 of the pair of covers 13 and 14. As shown in FIG. That is, the input side cover 13 is provided with a plurality of shaft holes 131 corresponding to the plurality of crankshafts 7A, 7B, 7C. Axial portions 71 of the crankshafts 7A, 7B, and 7C are inserted into the shaft holes 131, respectively. Here, the inner diameter of each shaft hole 131 is set to be one size larger than the outer diameter of the shaft center portion 71 so that the shaft center portion 71 does not come into contact with the inner peripheral surface of the shaft hole 131 .

By the way, the configuration around each of the crankshafts 7A, 7B, and 7C will be described in more detail. The gear device 1A according to this reference example employs configurations as shown in FIGS. 9 to 11. FIG. Here, the crankshaft 7A will be described as an example, but the same configuration is adopted for the crankshafts 7B and 7C.

That is, the crankshaft 7A has a flange portion 73 between two eccentric portions 72 in the axial direction along the axis Ax2. The flange portion 73 has a disc shape centered on the axis Ax2, and at least the outer peripheral surface thereof is a perfect circle in a plan view. The outer diameter of the flange portion 73 is set to be one size larger than the outer diameter of the eccentric portion 72 , and the flange portion 73 has a flange shape protruding from the outer peripheral surface of the eccentric portion 72 over the entire circumference. In this reference example, as an example, the axial center portion 71, the two eccentric portions 72, and the flange portion 73 are seamlessly integrated.

Here, since the crankshaft 7A has two eccentric portions 72 with respect to one axial center portion 71, it has stepped portions 70 at least at two locations in the axial direction. In other words, the diameter of the crankshaft 7A is not uniform over its entire length, but changes at least between the axial center portion 71 and each eccentric portion 72, so that two stepped portions 70 are produced at this portion. In other words, the end surface of each eccentric portion 72 facing outward in the axial direction (that is, the side opposite to the flange portion 73 ) serves as the stepped portion 70 .

In this reference example, the shaft center portion 71 of the crankshaft 7A has a smaller diameter at both ends in the axial direction than at the central portion in the axial direction. Therefore, the stepped portion 70 is also generated at each portion where the diameter of the axial portion 71 changes. As a result, the crankshaft 7A has stepped portions 70 at four locations in the axial direction. Here, when distinguishing the respective stepped portions 70, the first stepped portion 701, the second stepped portion 702, the third stepped portion 703, and the input side of the rotation axis Ax1 (the right side in FIG. 7) are respectively referred to. A fourth step portion 704 is assumed. In other words, the first stepped portion 701 and the second stepped portion 702 are end faces facing the input side of the rotation axis Ax1, and the third stepped portion 703 and the fourth stepped portion 704 are the edges of the rotation axis Ax1. It is the end face facing the output side. An end portion of the axial center portion 71 closer to the input side of the rotation axis Ax1 than the first stepped portion 701 constitutes a mounting portion 74 for mounting the crankshaft gear 502A.

A pair of rolling bearings 41 and 42, a pair of eccentric body bearings 5, washers 81 to 85 and a retaining ring 86 are combined with the crankshaft 7A. That is, the eccentric body bearings 5 are attached to the two eccentric portions 72 of the crankshaft 7A. Further, a pair of rolling bearings 41 and 42 are mounted at positions on both sides of the two eccentric portions 72 in the axial direction of the shaft center portion 71 of the crankshaft 7A. Further, a groove 75 for fitting a retaining ring 86 is formed at the end of the axial center portion 71 of the crankshaft 7A further to the output side (left side in FIG. 7) of the rotation shaft Ax1 than the fourth stepped portion 704. formed. Therefore, a snap ring 86 is attached to the end of the shaft center portion 71 on the output side of the rotation axis Ax1.

Here, the washer 81, the eccentric body bearing 5, the washer 82, and the rolling bearing 41 are arranged in this order from the flange portion 73 side on the input side (the right side in FIG. 7) of the rotation axis Ax1 as viewed from the flange portion 73. is attached to the On the other hand, a washer 83, an eccentric bearing 5, a washer 84, a rolling bearing 42, a washer 85, and a retaining ring 86 are arranged on the output side (left side in FIG. 7) of the rotation axis Ax1 as viewed from the flange portion 73. are installed so that they are lined up in this order. Therefore, on the input side of the rotation axis Ax1 as viewed from the flange portion 73, a washer 81 is interposed between the flange portion 73 and the eccentric bearing 5, and a washer 82 is interposed between the eccentric bearing 5 and the rolling bearing 41. Intervene. On the output side of the rotation axis Ax1 as viewed from the flange portion 73, a washer 83 is interposed between the flange portion 73 and the eccentric bearing 5, and a washer 84 is interposed between the eccentric bearing 5 and the rolling bearing 42. . Further, the rolling bearing 42 contacts the retaining ring 86 via the washer 85, thereby restricting the movement of the rotating shaft Ax1 toward the output side.

More specifically, the eccentric portions 72 are inserted into the washers 81 and 83, respectively, and the axial portions 71 are inserted into the washers 82 and 84, respectively. Here, a washer 82 is interposed between the second stepped portion 702 of the crankshaft 7A and the rolling bearing 41 . On the other hand, a washer 84 is interposed between the third stepped portion 703 of the crankshaft 7A and the rolling bearing 42 . Further, a washer 85 is interposed between the fourth stepped portion 704 of the crankshaft 7A and the snap ring 86. As shown in FIG. These washers 81 to 85 are made of metal, for example, and function as bearing rings (bearing washers) that reduce friction between two members.

By the way, as shown in FIG. 12, the gear device 1A according to this reference example includes a restricting structure 9 that restricts axial movement of each of the crankshafts 7A, 7B, and 7C. That is, in the gear device 1A according to this reference example, the regulation structure 9 regulates axial movement of the crankshafts 7A, 7B, and 7C. The “axial direction” in the present disclosure means a direction along the axis Ax2 of the crankshafts 7A, 7B, 7C, particularly a direction (thrust direction) parallel to the axis Ax2 of the crankshafts 7A, 7B, 7C. In addition, "restrict movement" as used in the present disclosure means to impose some kind of restriction on movement, and not only to completely prohibit movement, but also to limit the range of movement or make it difficult to move. including. In other words, in this reference example, the movement of the crankshafts 7A, 7B, 7C in the axial direction along the axial center Ax2 of the crankshafts 7A, 7B, 7C is restricted by providing the restricting structure 9. become.

In this reference example, as an example, the regulation structure 9 prohibits movement of the crankshafts 7A, 7B, and 7C in both one axial direction (the input side of the rotating shaft Ax1) and the other axial direction (the output side of the rotating shaft Ax1). It is assumed that That is, in the example of FIG. 8, the restriction structure 9 prohibits the pair of carriers 18 and 19 from moving the crankshafts 7A, 7B, and 7C to the right in the drawing and to the left in the drawing. do. Thereby, the positions of the crankshafts 7A, 7B, 7C in the axial direction are positioned at fixed positions (relative to the pair of carriers 18, 19).

Specifically, in this reference example, the regulating structure 9 includes a pair of covers 13 and 14 attached to both axial sides of a pair of carriers 18 and 19 . In short, the gear device 1A regulates axial movement of each of the crankshafts 7A, 7B, 7C using the input side cover 13 and the output side cover 14 described above. In particular, the gear device 1A according to this reference example includes, as the regulating structure 9, a first regulating structure 91 that regulates movement of the crankshafts 7A, 7B, and 7C in one axial direction (rightward in FIG. 8), and and a second restricting structure 92 that restricts the movement of the crankshafts 7A, 7B, 7C to the other (left in FIG. 8).

Here, the input side cover 13 is included in the first restricting structure 91 and receives a force F1 acting in one direction (rightward in FIG. 8) in the axial direction from the crankshafts 7A, 7B, 7C. It restricts the movement of the crankshafts 7A, 7B, 7C in one direction. On the other hand, the output side cover 14 is included in the second regulating structure 92 and receives force F2 acting in the other axial direction (leftward in FIG. 8) from the crankshafts 7A, 7B, 7C. movement of the crankshafts 7A, 7B, 7C to the other of the two.

More specifically, the first restricting structure 91 includes the input side cover 13 and first stepped portions 701 of the crankshafts 7A, 7B, 7C. According to the first restricting structure 91, rotation of the crankshafts 7A, 7B, and 7C is provided around the shaft hole 131 on the surface of the input side cover 13 facing the output side (left side in FIG. 8) of the rotation axis Ax1. The movement of the crankshafts 7A, 7B, and 7C in one axial direction (rightward in FIG. 8) is restricted by contact with the first stepped portion 701 facing the input side (rightward in FIG. 8) of the axis Ax1. be done. That is, when the first stepped portion 701 of the crankshafts 7A, 7B, 7C contacts the input-side cover 13 attached to the input-side carrier 18, the crankshafts 7A, 7B, 7C move in one axial direction. Movement is prohibited.

The second regulating structure 92 includes the output side cover 14 and an end face 76 on the output side of the rotation axis Ax1 of the crankshafts 7A, 7B, 7C. According to the second regulating structure 92, the output side (right side in FIG. 8) of the rotation axis Ax1 of the crankshafts 7A, 7B, and 7C is provided on the surface of the output side cover 14 facing the input side (right side in FIG. 8) of the rotation axis Ax1. The movement of the crankshafts 7A, 7B, and 7C in the other axial direction (leftward in FIG. 8) is restricted by the contact of the end face 76 facing the leftward in FIG. That is, when the end faces 76 of the crankshafts 7A, 7B, 7C come into contact with the output-side cover 14 attached to the output-side carrier 19, movement of the crankshafts 7A, 7B, 7C in the other axial direction is prohibited. be.

Here, in the regulating structure 9, the ends of the eccentric portions 72 of the crankshafts 7A, 7B, 7C (the second stepped portion 702 and the third stepped portion 703) come into contact with the pair of covers 13, 14. It is a part other than. That is, the regulating structure 9 is located axially outside of the stepped portions 702, 703 formed by the end surfaces of the eccentric portions 72 of the crankshafts 7A, 7B, 7C, and the end surfaces (first The axial movement of the crankshafts 7A, 7B, and 7C is restricted by contacting the stepped portion 701 or the end face 76) of the crankshafts 7A, 7B, and 7C. Therefore, at the stepped portions 702 and 703 formed by the end faces of the eccentric portion 72, friction does not occur due to contact with the pair of covers 13 and 14, and wear and the like of the stepped portions 702 and 703 can be reduced.

By the way, the gear device 1A according to this reference example includes an internal gear 2, a planetary gear 3, crankshafts 7A, 7B, and 7C, and a pair of carriers 18 and 19, and causes the planetary gear 3 to oscillate. As a result, the planetary gear 3 is rotated relative to the internal gear 2 . The internal gear 2 includes an annular gear main body 22 and a plurality of outer pins 23 that are held in a rotatable state in a plurality of inner peripheral grooves 223 formed in an inner peripheral surface 221 of the gear main body 22 and that constitute the internal teeth 21 . and have The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21 . The crankshafts 7A, 7B, and 7C have stepped portions 70 at at least two locations in the axial direction along the axis Ax2, and oscillate the planetary gears 3 by rotating about the axis Ax2. A pair of carriers 18 and 19 are arranged on both axial sides of the planetary gear 3 and rotatably support the crankshafts 7A, 7B and 7C. Here, as shown in FIG. 13, between the stepped portion 70 and the pair of carriers 18 and 19, lubricating passages S1 are formed for passing lubricant.

That is, in this reference example, the lubricating path S1 is secured between the stepped portion 70 and the pair of carriers 18 and 19 . By securing such a lubricating path S1, in the gear device 1A, the lubricant can be circulated through the lubricating path S1, and the lubrication state of the pair of rolling bearings 41 and 42, the pair of eccentric body bearings 5, and the like can be improved. can be improved. In FIG. 13, the state in which the lubricant flows (circulates) through the lubricating path S1 is conceptually represented by dashed arrows.

In this reference example, the lubricating path S1 is formed within a lubricant holding space 17 into which the lubricant is injected. By forming such a lubricating path S1, it is difficult for "lubricant shortage", i.e., insufficient or depleted lubricant, to occur around the crankshafts 7A, 7B, and 7C, and a constant amount or more of lubricant is always supplied. will be Moreover, compared to a structure in which the lubricant stays at a fixed position, the lubricant circulates through the lubricating passage S1, so that the lubricant around the crankshafts 7A, 7B, and 7C is replaced as needed. It is possible to suppress deterioration of the lubricant.

Therefore, the lubricating state of the pair of rolling bearings 41, 42, the pair of eccentric body bearings 5, etc. is improved, and poor lubrication is less likely to occur. Therefore, even when the gear device 1A is used for a long period of time, the loss due to friction can be reduced, and the life of the gear device 1A can be easily extended. In short, the gear device 1A according to this reference example is less likely to deteriorate in reliability even when used for a long period of time, which leads to improved transmission efficiency, longer life, and higher performance of the gear device 1A. .

Here, in this reference example, the lubrication passage S1 includes a radial passage S11 through which the lubricant passes in a radial direction orthogonal to the axial direction. That is, as shown in FIG. 14, which is a schematic enlarged view of the region Z1 in FIG. 13, the lubrication path S1 formed between the stepped portion 70 and the pair of carriers 18 and 19 extends at least in the radial direction. It includes a radial passage S11 for conducting lubricant. As a result, when the crankshafts 7A, 7B, and 7C rotate, the lubricant can be efficiently circulated through the lubrication path S1 by passing the lubricant in the radial direction due to the centrifugal force.

In this reference example, there is a gap in the axial direction between the stepped portions 702 and 703 and at least one of the pair of carriers 18 and 19, and the lubrication path S1 fills the gap. include. In this reference example, as described above, at least the stepped portions 702 and 703 formed by the end surfaces of the eccentric portion 72 are not used as the regulating structure 9. A gap is provided between them, and this gap can be part of the lubrication path S1. In this reference example, as an example, gaps between the stepped portions 702 and 703 and both the pair of carriers 18 and 19 constitute a part of the lubrication path S1.

Furthermore, in this reference example, plate-like parts (washers 82 and 84) arranged between the stepped portion 70 and the pair of carriers 18 and 19 are further provided. The lubricating path S1 includes a groove portion 80 (see FIG. 10) formed in the surface of the plate-shaped parts (washers 82, 84) facing the carriers 18, 19. As shown in FIG. That is, as shown in FIG. 10, grooves 80 extending in the radial direction are formed in the surfaces of the washers 81 to 84 facing outward in the axial direction (toward the carriers 18 and 19). Here, it is preferable to form a plurality of grooves 80 for each of the washers 81 to 84, and in this reference example, as an example, four grooves 80 are formed for each of the washers 81 to 84. FIG. The four grooves 80 are arranged at equal intervals in the circumferential direction of each of the washers 81-84. By providing such a groove portion 80, the lubricant flows through the groove portion 80, and the groove portion 80 is included in the lubrication path S1. As a result, the cross-sectional area of the lubricating passage S1 can be increased compared to the case where the groove portion 80 is not provided, and the lubricant can be circulated more easily.

Further, when a plurality of crankshafts 7A, 7B, 7C are provided as in this reference example, a plurality of lubricating passages S1 formed around the plurality of crankshafts 7A, 7B, 7C are connected. A path S2 is preferably provided. As a result, the lubricant can be circulated between the plurality of crankshafts 7A, 7B, and 7C, and the lubricant can be circulated throughout the gear device 1A, so further improvement of the lubricating state can be expected.

Specifically, as shown in FIG. 7, grooves 133 and 143 are formed in the surfaces facing inward in the axial direction (surfaces on the planetary gear 3 side) in each of the pair of covers 13 and 14 . The grooves 133, 143 are annular grooves centered on the rotation axis Ax1, which are formed so as to pass through the rolling bearings 41, 42 supporting the respective crankshafts 7A, 7B, 7C in plan view. (See Figure 8). Therefore, the lubricating path S1 including a plurality of (three in this case) rolling bearings 41 are connected by the connecting path S2 formed by the groove 133 of the input side cover 13 . Similarly, the lubricating path S1 including a plurality of (three in this case) rolling bearings 42 are connected by a connecting path S2 formed by the groove 143 of the output side cover 14 .

Further, the gear device 1A according to this reference example includes an input gear 501 that rotates about the rotation axis Ax1, and a plurality of crankshaft gears 502A, 502B, and 502C. A plurality of crankshaft gears 502A, 502B, 502C are arranged around the input gear 501 so as to mesh with the input gear 501 and rotate synchronously with each other when the input gear 501 rotates. A plurality of crankshafts 7A, 7B, 7C are provided so as to correspond one-to-one with the plurality of crankshaft gears 502A, 502B, 502C. The plurality of crankshafts 7A, 7B, 7C rotate together with the plurality of crankshaft gears 502A, 502B, 502C to oscillate the planetary gear 3 around the rotation axis Ax1.

Thus, in the distribution type gear device 1A having the plurality of crankshafts 7A, 7B, 7C, the axial movement of the plurality of crankshafts 7A, 7B, 7C can be restricted. Furthermore, by circulating the lubricant around the plurality of crankshafts 7A, 7B, 7C, it is possible to improve the lubricating state.

As shown in FIG. 15, the gear device 1A according to this reference example constitutes a robot joint device 200 together with a first member 201 and a second member 202. As shown in FIG. In other words, the robot joint device 200 according to this reference example includes the gear device 1A, the first member 201, and the second member 202. As shown in FIG. The first member 201 is fixed to the gear body 22 . The second member 202 rotates relative to the first member 201 as the planetary gear 3 rotates relative to the internal gear 2 . FIG. 15 is a schematic cross-sectional view of the robot joint device 200. As shown in FIG. 15 schematically shows the first member 201, the second member 202, and the drive source 101. FIG.

The robot joint device 200 configured in this manner functions as a joint device by relatively rotating the first member 201 and the second member 202 about the rotation axis Ax1. Here, by driving the input shaft 500 of the gear device 1A with the drive source 101, the first member 201 and the second member 202 rotate relatively. At this time, the rotation (input rotation) generated by the drive source 101 is reduced at a relatively high speed reduction ratio in the gear device 1A to drive the first member 201 or the second member 202 with relatively high torque. That is, the first member 201 and the second member 202 connected by the gear device 1A can bend and stretch about the rotation axis Ax1.

The robot joint device 200 is used, for example, in a robot such as a horizontal articulated robot (SCARA robot). Furthermore, the robot joint device 200 is not limited to horizontal articulated robots, and may be used, for example, in industrial robots other than horizontal articulated robots or non-industrial robots. Further, the gear device 1A according to the present reference example is not limited to the robot joint device 200, and may be used in a vehicle such as an automated guided vehicle (AGV) as a wheel device such as an in-wheel motor. good.

<Modification>
Reference Example 1 is but one of various reference examples of the present disclosure. Reference Example 1 can be variously modified in accordance with the design or the like as long as the object of the present disclosure can be achieved. In addition, the drawings referred to in this disclosure are all schematic diagrams, and the ratio of the size and thickness of each component in the drawings does not necessarily reflect the actual dimensional ratio. . Modifications of Reference Example 1 are listed below. Modifications described below can be applied in combination as appropriate.

The number of crankshafts 7A, 7B, 7C is not limited to "3" and may be 2 or 4 or more. Furthermore, if there is only one crankshaft, an eccentric oscillation type internally meshing planetary gear device in which the rotation axis Ax1 and the crankshaft axis Ax2 are aligned is realized instead of the distribution type. In this case, the planetary gear 3 is oscillated by driving the crankshaft, and the pair of carriers 18 and 19 can be rotated relative to the gear body 22 about the rotation axis Ax1.

Moreover, although the planetary gear 3 illustrated the gear apparatus 1A of two types in the reference example 1, the gear apparatus 1A may be provided with the planetary gear 3 three or more. For example, when the gear device 1A includes three planetary gears 3, these three planetary gears 3 are preferably arranged with a phase difference of 120 degrees around the rotation axis Ax1. Further, the gear device 1A may include only one planetary gear 3. Alternatively, when the gear device 1A includes three planetary gears 3, two planetary gears 3 out of the three planetary gears 3 are in the same phase, and the remaining one planetary gear 3 is 180 degrees around the rotation axis Ax1. They may be arranged with a phase difference.

Moreover, the bearing member 6 may be a cross roller bearing, a deep groove ball bearing, a four-point contact ball bearing, or the like.

Further, the number of teeth of the input gear 501, the number of teeth of the crankshaft gears 502A, 502B, and 502C, the number of the outer pins 23 (the number of teeth of the inner teeth 21), the number of teeth of the outer teeth 31, etc. described in Reference Example 1 are , are only examples, and can be changed as appropriate.

Moreover, the eccentric body bearing 5 is not limited to a roller bearing, and may be, for example, a deep groove ball bearing, an angular ball bearing, or the like.

Further, the material of each component of the gear device 1A is not limited to metal, and may be, for example, resin such as engineering plastic.

Further, the gear device 1A only needs to be able to take out the relative rotation between the inner ring 61 and the outer ring 62 of the bearing member 6 as an output, and the rotational force of the inner ring 61 (the input side carrier 18 and the output side carrier 19) is It is not limited to the configuration taken out as an output. For example, the rotational force of the outer ring 62 (case 10) that rotates relative to the inner ring 61 may be extracted as an output.

In Reference Example 1, the end faces 76 of the crankshafts 7A, 7B, and 7C on the output side of the rotation axis Ax1 are in direct contact with the output side cover 14. A plate-like component such as a shim member may be arranged between the side cover 14 and the side cover 14 . In this case, when attaching the output side cover 14, the gap between the end face 76 and the output side cover 14 in the axial direction can be adjusted by adjusting the thickness (and/or number) of the plate-shaped parts. , the "play" in the axial direction of the crankshafts 7A, 7B, 7C can be adjusted. Further, the plate-shaped part functions as a bearing ring (race washer) that reduces friction between the end surface 76 and the output side cover 14 .

Further, the lubricant is not limited to a liquid substance such as lubricating oil (oil), but may be a gel substance such as grease.

(Embodiment 1)
As shown in FIGS. 16 and 17, the internal meshing planetary gear device 1B (hereinafter also simply referred to as the "gear device 1B") according to the present embodiment does not include the output side cover 14 (see FIG. 7). It is different from the gear device 1A according to the reference example 1 in this point. Hereinafter, the same reference numerals are assigned to the same configurations as in Reference Example 1, and the description thereof will be omitted as appropriate. FIG. 16 is a schematic cross-sectional view of the gear device 1B. FIG. 17 is a schematic enlarged view of area Z1 of FIG. 16, showing a partially enlarged view in a balloon.

In the gear device 1B according to the present embodiment, instead of the output side cover 14, the input side cover 13, the retaining ring 87 and the washer 88 regulate the axial movement of the crankshafts 7A, 7B and 7C in the other direction. do. Further, movement of each of the crankshafts 7A, 7B, and 7C in one direction in the axial direction is restricted by the input side cover 13 and the stepped portion (first stepped portion 701) as in the first reference example.

That is, the gear device 1B includes an internal gear 2, planetary gears 3, crankshafts 7A, 7B, 7C, an input side carrier 18 and an output side carrier 19, and by oscillating the planetary gears 3, , rotates the planetary gear 3 relative to the internal gear 2 . The internal gear 2 includes a ring-shaped gear body 22 and a plurality of outer pins 23 that are held in a rotatable state in a plurality of inner peripheral grooves 223 formed in an inner peripheral surface 221 of the gear body 22 and that constitute the internal teeth 21 . and have The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21 . The crankshafts 7A, 7B, and 7C oscillate the planetary gear 3 by rotating around the axis Ax2. The input side carrier 18 and the output side carrier 19 are arranged on both sides in the axial direction along the axis Ax2 of the planetary gear 3, and rotatably support the crankshafts 7A, 7B, 7C. Here, the gear device 1B further includes a regulating structure 9, as shown in FIG. The restricting structure 9 restricts the axial movement of the crankshafts 7A, 7B, 7C in either one of the input-side carrier 18 and the output-side carrier 19 .

Thus, in this embodiment, only one of the input side carrier 18 and the output side carrier 19 regulates the axial movement of the crankshafts 7A, 7B, and 7C in both axial directions (one and the other). Especially in this embodiment, only the input side carrier 18 out of the input side carrier 18 and the output side carrier 19 restricts the axial movement of the crankshafts 7A, 7B, 7C in both axial directions. 19 is not used for restricting axial movement of the crankshafts 7A, 7B, 7C. That is, in the gear device 1B, the movement of the crankshafts 7A, 7B, and 7C in both axial directions can be restricted by using only the input side cover 13 instead of the output side cover 14. FIG. As a result, the gear device 1B has a relatively simple configuration without using a tapered roller bearing or the output side cover 14 attached to the output side carrier 19 (or the input side cover 13 attached to the input side carrier 18). Despite this, it is possible to restrict axial movement of the crankshafts 7A, 7B, and 7C. Therefore, according to the configuration of the present embodiment, it is possible to reduce rattling, transmission loss, etc. due to axial movement of the crankshafts 7A, 7B, 7C.

Moreover, the gear device 1B according to the present embodiment has the following advantages over the gear device 1A according to the first reference example. That is, the mounting holes 194 provided in the output-side carrier 19 can be deepened by the thickness of the output-side cover 14, and the mounting strength of the mating member to the output-side carrier 19 can be easily improved. Furthermore, since the output side cover 14 having the plurality of through holes 141 corresponding to the plurality of mounting holes 194 is omitted, it is not necessary to adjust the arrangement and number of the through holes 141 according to the mating member. Moreover, since the fixing bolts 142 (see FIG. 8) for attaching the output side cover 14 to the output side carrier 19 are unnecessary, it is possible to provide the mounting holes 194 without interfering with the fixing bolts 142 .

Specifically, in this embodiment, the snap ring 87 for fixing the crankshaft gears 502A, 502B, 502C to the crankshafts 7A, 7B, 7C is indirectly connected to the input side through the washer 88. contact the cover 13; That is, in order to position the crankshaft gears 502A, 502B, 502C with respect to the crankshafts 7A, 7B, 7C in the axial direction, the input side (right side in FIG. 16) of the rotation axis Ax1 of each crankshaft 7A, 7B, 7C A pair of retaining rings 87, 89 are attached to the ends. The pair of retaining rings 87, 89 axially sandwich the crankshaft gears 502A, 502B, 502C to restrict axial movement of the crankshaft gears 502A, 502B, 502C relative to the crankshafts 7A, 7B, 7C. Of the pair of retaining rings 87 and 89, the retaining ring 87 located on the output side (left side in FIG. 16) of the rotating shaft Ax1, that is, on the input side cover 13 side when viewed from the crankshaft gears 502A, 502B, and 502C, is the indirect By directly contacting the input side cover 13, the movement of each of the crankshafts 7A, 7B, 7C in the other axial direction is restricted.

In this way, the retaining ring 87 attached to the crankshafts 7A, 7B, and 7C is provided around the shaft hole 131 on the input side (right side in FIG. 16) surface of the rotating shaft Ax1 in the input side cover 13. are in indirect contact. On the other hand, on the surface of the input side cover 13 on the output side (the left side in FIG. 17) of the rotating shaft Ax1, around the shaft hole 131, there are stepped portions 70 (first stepped portions) of the crankshafts 7A, 7B, and 7C. 701) come into contact. As a result, the input-side cover 13 attached to the input-side carrier 18 is sandwiched between the snap ring 87 and the stepped portion 70 (first stepped portion 701), and the crankshafts 7A, 7B, and 7C are clamped. axial movement of is restricted. In short, the regulating structure 9 includes the input side cover 13, and by sandwiching the input side cover 13 between the snap ring 87 and the stepped portion 70, axial movement of the crankshafts 7A, 7B, 7C with respect to the input side carrier 18 is restricted. to regulate

More specifically, as shown in FIG. 17, the first restricting structure 91 includes the input side cover 13 and the first stepped portions 701 of the crankshafts 7A, 7B, 7C, similarly to the first reference example. I'm in. According to the first regulating structure 91, the input side of the rotation axis Ax1 of the crankshafts 7A, 7B, and 7C is arranged around the shaft hole 131 in the surface of the input side cover 13 facing the output side of the rotation axis Ax1. The movement of the crankshafts 7A, 7B, and 7C in one direction in the axial direction is restricted by the contact of the facing first stepped portions 701 . That is, when the first stepped portion 701 of the crankshafts 7A, 7B, 7C contacts the input-side cover 13 attached to the input-side carrier 18, the crankshafts 7A, 7B, 7C move in one axial direction. Movement is prohibited. In other words, the input-side cover 13 attached to the input-side carrier 18 receives a force F1 acting in one axial direction (rightward in FIG. 17) from the crankshafts 7A, 7B, and 7C. movement of the crankshafts 7A, 7B, 7C to one side is prohibited.

In short, in the first regulating structure 91, the portions of the crankshafts 7A, 7B, 7C other than the end surfaces of the eccentric portions 72 (the second stepped portions 702) come into contact with the input side cover 13. As shown in FIG. That is, the first regulating structure 91 is positioned axially outside (to the right in FIG. 17) of the end surface (second stepped portion 702) of the eccentric portion 72 of the crankshafts 7A, 7B, and 7C. By bringing the stepped portion (first stepped portion 701) facing the outside of the input side cover 13 directly or indirectly into contact with the input side cover 13, the movement of the crankshafts 7A, 7B, 7C in one axial direction regulate. Therefore, at the second stepped portion 702 formed by the end surface of the eccentric portion 72, friction does not occur due to contact with the input side cover 13, and wear and the like of the stepped portion 702 can be reduced. In the present embodiment, the first stepped portion 701 is brought into direct contact with the input side cover 13. However, the configuration is not limited to this, and the first stepped portion 701 contacts the input side cover 13 via a washer or the like. may be indirectly contacted.

The second restricting structure 92 includes the input side cover 13, a snap ring 87, and a washer 88. According to the second restricting structure 92, the surface of the input side cover 13 facing the input side (the right side in FIG. 17) of the rotation axis Ax1 and the surface of the retaining ring 87 facing the output side of the rotation axis Ax1 are aligned. The contact (indirectly via the washer 88) restricts the movement of the crankshafts 7A, 7B, 7C in the other axial direction (to the left in FIG. 17). That is, the input side cover 13 receives a force F2 acting from the snap ring 87 toward the other axial direction (leftward in FIG. 17) via the washer 88, thereby moving the crankshaft 7A in the other axial direction. , 7B, 7C are prohibited from moving.

That is, in this embodiment, the regulation structure 9 includes the input side cover 13 attached to the input side carrier 18 on the opposite side of the planetary gear 3 in the axial direction. By sandwiching the input side cover 13 between a pair of projections (the first stepped portion 701 and the snap ring 87) provided on the outer peripheral surface of the crankshafts 7A, 7B, 7C, the axial direction of the crankshafts 7A, 7B, 7C can be adjusted. restrict movement to Therefore, axial movement of the crankshafts 7A, 7B, and 7C can be reliably restricted. However, the pair of protrusions provided on the outer peripheral surfaces of the crankshafts 7A, 7B, and 7C are not limited to the first stepped portion 701 and the snap ring 87, and are, for example, a pair of stoppers attached to the crankshafts 7A, 7B, and 7C. It may be a ring, or a rib or the like provided integrally with the axial center portion 71 on a part of the outer peripheral surface of the crankshafts 7A, 7B, 7C.

Further, in this embodiment, the input side cover 13 in the regulation structure 9 is detachably attached to the input side carrier 18 . That is, the input side cover 13 is a separate member from the input side carrier 18, and is attached to the input side carrier 18 when assembling the gear device 1B. Therefore, when assembling the gear device 1B, after inserting the crankshafts 7A, 7B, 7C from the input-side carrier 18 side, the input-side cover 13 is attached to the input-side carrier 18. Axial movement of 7C can be restricted. Therefore, by adjusting the mounting position of the input side cover 13 with respect to the input side carrier 18, the axial "play" of the crankshafts 7A, 7B, 7C can be adjusted.

Here, it is preferable that a shim member 132 is interposed between the input side carrier 18 and the input side cover 13, as shown in the balloon of FIG. The shim member 132 is, for example, a metal thin plate member. That is, the input side cover 13 contacts the input side carrier 18 via the shim member 132 in the axial direction. By adjusting the thickness (and/or number) of the shim members 132 when attaching the input side cover 13, the gap between the first stepped portion 701 and the input side cover 13 in the axial direction can be adjusted. and the axial "play" of the crankshafts 7A, 7B, 7C can be adjusted.

Furthermore, in the present embodiment, in the restricting structure 91, the stepped portions 70 (first stepped portions 701) of the crankshafts 7A, 7B, and 7C and the snap ring 87 are attached to the input side carrier 18, and the input side cover 13 Axial movement of the crankshafts 7A, 7B, 7C is restricted by direct or indirect contact with the . That is, the axial movement of the crankshafts 7A, 7B, and 7C is restricted by the input side cover 13 rather than by the input side carrier 18 . Since the input side cover 13 is detachably attached to the input side carrier 18 , it is separate from the input side carrier 18 . Therefore, while restricting the movement of the crankshafts 7A, 7B, 7C in both axial directions, between the stepped portion 70 and the pair of carriers 18, 19, a part of the lubricating passage S1 through which the lubricant passes and the It is possible to secure a gap.

Therefore, in this embodiment, as in Reference Example 1, between the two stepped portions 70 (the second stepped portion 702 and the third stepped portion 703) and the input side carrier 18 and the output side carrier 19, , lubricating passages S1 through which lubricant passes are formed. Therefore, the lubricating state of the pair of rolling bearings 41, the pair of eccentric body bearings 5, etc. is improved, and poor lubrication is less likely to occur. Therefore, even when the gear device 1B is used for a long period of time, the loss due to friction can be reduced, and the life of the gear device 1B can be easily extended. In short, the gear device 1B according to the present embodiment is less likely to deteriorate in reliability even when used for a long period of time, which leads to improved transmission efficiency, longer life, and higher performance of the gear device 1B. .

Further, similarly to Reference Example 1, the gear device 1B according to this embodiment includes an input gear 501 that rotates about the rotation axis Ax1, and a plurality of crankshaft gears 502A, 502B, and 502C. A plurality of crankshaft gears 502A, 502B, 502C are arranged around the input gear 501 so as to mesh with the input gear 501 and rotate synchronously with each other when the input gear 501 rotates. A plurality of crankshafts 7A, 7B, 7C are provided so as to correspond one-to-one with the plurality of crankshaft gears 502A, 502B, 502C. The plurality of crankshafts 7A, 7B, 7C rotate together with the plurality of crankshaft gears 502A, 502B, 502C to oscillate the planetary gear 3 around the rotation axis Ax1.

Thus, in the distribution type gear device 1B having the plurality of crankshafts 7A, 7B, 7C, the axial movement of the plurality of crankshafts 7A, 7B, 7C can be restricted. Furthermore, by circulating the lubricant around the plurality of crankshafts 7A, 7B, 7C, it is possible to improve the lubricating state.

By the way, in Embodiment 1, the restriction structure 9 is provided only at the input side carrier 18 (strictly speaking, the input side cover 13 attached to the input side carrier 18) of the input side carrier 18 and the output side carrier 19, and the crankshaft 7A , 7B, and 7C in both axial directions (one and the other), the configuration is not limited to this. That is, the restricting structure 9 may restrict movement of the crankshafts 7A, 7B, and 7C in both axial directions with only one of the input side carrier 18 and the output side carrier 19 .

Therefore, for example, the restriction structure 9 may be configured to restrict axial movement of the crankshafts 7A, 7B, and 7C only in the output-side carrier 19 . In this case, the output side carrier 19 not only directly restricts the axial movement of the crankshafts 7A, 7B, 7C, but also the output side cover 14 attached to the output side carrier 19, for example, controls the crankshafts 7A, 7B, 7C. Axial movement of 7C may be restricted. According to this configuration, interference between the mounting structure and the like of the crankshaft gears 502A, 502B, 502C and the regulation structure 9 is less likely to occur.

The configuration (including modifications) of Embodiment 1 can be employed in appropriate combination with the various configurations (including modifications) described in Reference Example 1.

(summary)
As described above, the internally meshing planetary gear device (1, 1A, 1B) according to the first aspect includes an internal gear (2), a planetary gear (3), and crankshafts (7A, 7B, 7C). ), an input side carrier (18) and an output side carrier (19), and by oscillating the planetary gear (3), the planetary gear (3) is moved relative to the internal gear (2). rotate to The internal gear (2) is rotatably held in an annular gear body (22) and a plurality of inner peripheral grooves (223) formed in the inner peripheral surface (221) of the gear body (22). and a plurality of outer pins (23) forming teeth (21). The planetary gear (3) has external teeth (31) that partially mesh with the internal teeth (21). The crankshafts (7A, 7B, 7C) oscillate the planetary gear (3) by rotating around the axis (Ax2). An input side carrier (18) and an output side carrier (19) are arranged on both sides in the axial direction along the axis (Ax2) of the planetary gear (3) to rotate the crankshafts (7A, 7B, 7C). To support. The internally meshing planetary gear train (1, 1A, 1B) further includes a regulating structure (9). The restricting structure (9) restricts axial movement of the crankshafts (7A, 7B, 7C) in either one of the input carrier (18) and the output carrier (19).

According to this aspect, only one of the input side carrier (18) and the output side carrier (19) can move the crankshafts (7A, 7B, 7C) in both axial directions (one and the other). can be regulated. As a result, the internal meshing planetary gear device (1, 1A, 1B) does not use a tapered roller bearing or the like, and although it has a relatively simple configuration, the axial direction of the crankshaft (7A, 7B, 7C) movement can be regulated. Therefore, it is possible to reduce rattling, transmission loss, etc. due to axial movement of the crankshafts (7A, 7B, 7C).

In the internal meshing planetary gear device (1, 1A, 1B) according to the second aspect, in the first aspect, the regulating structure (9) is configured so that the planetary gear (3) and the planetary gear (3) in the axial direction of the input side carrier (18) includes an input side cover (13) attached to the opposite side. The regulating structure (9) regulates the axial direction of the crankshafts (7A, 7B, 7C) by sandwiching the input side cover (13) between a pair of projections provided on the outer peripheral surface of the crankshafts (7A, 7B, 7C). restrict movement to

According to this aspect, it is possible to reliably restrict the movement of the crankshafts (7A, 7B, 7C) in the axial direction.

In the internal meshing planetary gear device (1, 1A, 1B) according to the third aspect, in the second aspect, the input side cover (13) is detachably attached to the input side carrier (18). there is

According to this aspect, when assembling the internal meshing planetary gear device (1, 1A, 1B) or the like, after the crankshafts (7A, 7B, 7C) are inserted from the input side carrier (18) side, the input side carrier Axial movement of the crankshafts (7A, 7B, 7C) can be restricted only by attaching the input side cover (13) to (18).

In the internal meshing planetary gear system (1, 1A, 1B) according to the fourth aspect, in the first aspect, the regulating structure (9) is configured such that the crankshafts (7A, 7B, 7C) only at the output side carrier (19) ) in the axial direction.

According to this aspect, interference between the mounting structure of the members (crankshaft gears 502A, 502B, 502C, etc.) attached to the input side of the crankshafts (7A, 7B, 7C) and the regulation structure (9) is less likely to occur.

In the internal meshing planetary gear device (1, 1A, 1B) according to the fifth aspect, in any one of the first to fourth aspects, the crankshafts (7A, 7B, 7C) are arranged in at least two locations in the axial direction. It has a stepped portion (70). Between the two stepped portions (70) and the input side carrier (18) and the output side carrier (19), lubricating passages (S1) for passing lubricant are formed.

According to this aspect, the lubricant can be circulated by utilizing the gaps between the stepped portion (70) and the input side carrier (18) and the output side carrier (19) in the axial direction.

An internal meshing planetary gear device (1, 1A, 1B) according to a sixth aspect is, in any one of the first to fifth aspects, an input gear (501) that rotates about a rotation axis (Ax1); a plurality of crankshaft gears (502A, 502B, 502C) arranged around the input gear (501) to mesh with the gear (501) and rotating synchronously with each other when the input gear (501) rotates; Prepare. A plurality of crankshafts (7A, 7B, 7C) are provided so as to correspond one-to-one with the plurality of crankshaft gears (502A, 502B, 502C). The plurality of crankshafts (7A, 7B, 7C) rotate together with the plurality of crankshaft gears (502A, 502B, 502C) to oscillate the planetary gears (3) around the rotation axis (Ax1).

According to this aspect, in the distributed type internal meshing planetary gear device (1, 1A, 1B), the movement of the crankshafts (7A, 7B, 7C) in the axial direction is restricted while having a relatively simple configuration. It is possible.

A robot joint device (200) according to a seventh aspect is fixed to an internal meshing planetary gear device (1, 1A, 1B) according to any one of the first to sixth aspects and a gear body (22) a first member (201) and a second member (202) that rotates relative to the first member (201) as the planetary gear (3) rotates relative to the internal gear (2); , provided.

According to this aspect, it is possible to regulate the axial movement of the crankshafts (7A, 7B, 7C) while having a relatively simple configuration.

The configurations according to the second to sixth aspects are not essential configurations for the internal meshing planetary gear device (1, 1A, 1B), and can be omitted as appropriate.

Reference Signs List 1, 1A, 1B internally meshing planetary gear device 2 internal gear 3 planetary gear 7A, 7B, 7C crankshaft 9 regulation structure 13 input side cover 18 input side carrier 19 output side carrier 21 internal tooth 22 gear main body 23 outer pin 31 External teeth 70, 701, 702, 703, 704 Step (protrusion)
87 Retaining ring (protrusion)
200 robot joint device 201 first member 202 second member 221 inner peripheral surface (of gear body) 223 inner peripheral groove 501 input gears 502A, 502B, 502C crankshaft gear Ax1 rotation axis Ax2 axis S1 lubrication path

Claims (6)

an internal gear having an annular gear body and a plurality of outer pins that are held in a rotatable state in a plurality of inner peripheral grooves formed on the inner peripheral surface of the gear body and constitute internal teeth;
a planetary gear having external teeth that partially mesh with the internal teeth;
a crankshaft that oscillates the planetary gear by rotating about its axis;
an input-side carrier and an output-side carrier arranged on both sides in the axial direction along the axial center of the planetary gear and rotatably supporting the crankshaft;
Rotating the planetary gear relative to the internal gear by oscillating the planetary gear;
further comprising a restricting structure restricting movement of the crankshaft in both of the axial directions in only one of the input side carrier and the output side carrier ;
The regulating structure includes an input-side cover attached to the input-side carrier on the opposite side of the planetary gear in the axial direction, and the input-side cover is positioned between a pair of projections provided on the outer peripheral surface of the crankshaft. restricting movement of the crankshaft in the axial direction by pinching;
Inscribed planetary gear system. an internal gear having an annular gear body and a plurality of outer pins that are held in a rotatable state in a plurality of inner peripheral grooves formed on the inner peripheral surface of the gear body and constitute internal teeth;
a planetary gear having external teeth that partially mesh with the internal teeth;
a crankshaft that oscillates the planetary gear by rotating about its axis;
an input-side carrier and an output-side carrier arranged on both sides in the axial direction along the axial center of the planetary gear and rotatably supporting the crankshaft;
Rotating the planetary gear relative to the internal gear by oscillating the planetary gear;
further comprising a restricting structure restricting movement of the crankshaft in both of the axial directions in only one of the input side carrier and the output side carrier;
wherein the restricting structure restricts movement of the crankshaft in the axial direction only in the output-side carrier;
Inscribed planetary gear system. The input side cover is detachably attached to the input side carrier,
The internally meshing planetary gear system according to claim 1 . the crankshaft has stepped portions in at least two locations in the axial direction;
Between the two stepped portions and the input-side carrier and the output-side carrier, lubrication passages for passing a lubricant are formed, respectively.
The internal meshing planetary gear device according to any one of claims 1 to 3 . an input gear that rotates about an axis of rotation;
a plurality of crankshaft gears arranged around the input gear so as to mesh with the input gear and rotating in synchronization with each other when the input gear rotates;
A plurality of the crankshafts are provided so as to correspond to the plurality of crankshaft gears on a one-to-one basis,
the plurality of crankshafts rotate together with the plurality of crankshaft gears to oscillate the planetary gears about the rotation axis;
The internal meshing planetary gear device according to any one of claims 1 to 3 . an internal meshing planetary gear device according to any one of claims 1 to 3 ;
a first member fixed to the gear body;
a second member that rotates relative to the first member as the planetary gear rotates relative to the internal gear;
Joint device for robots.

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