Planetary gear device

Abstract

An internal meshing planetary gear device. An internal tooth gear (2) has an internal tooth (21) and is fixed to an outer ring (62A). A planetary gear (3) has an external tooth that partially meshes with the internal tooth (21). A plurality of internal pins (4) revolve within internal pin holes (32) formed in the planetary gear (3) in a state of being respectively inserted into the internal pin holes (32) and relatively rotate with respect to the internal tooth gear (2). An inner ring (61A) includes a first inner ring (601) and a second inner ring (602) that are opposed in a direction parallel to an axis of rotation (Ax1) and whose facing surfaces (601A, 602A) contact each other. The first inner ring (601) has a plurality of holding holes (611) through which the plurality of internal pins (4) respectively pass in a direction parallel to the axis of rotation (Ax1). The plurality of internal pins (4) are each held to the inner ring (61A) in a state of being able to rotate on their own.

Description

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Japanese Patent Application No. 2020-210657, filed on December 18, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to internal meshing planetary gear devices, and more specifically, to internal meshing planetary gear devices in which a planetary gear with external teeth is disposed inside an internal gear having internal teeth. Background Technology

[0004] As a related technology, there are known gear devices of the so-called eccentric oscillation type, in which a planetary gear engages with an internal gear while eccentrically oscillating (for example, see Patent Document 1). In the gear device of the related technology, the eccentric body is integrally formed with the input shaft, and the planetary gear is mounted on the eccentric body via an eccentric body bearing. External teeth such as arc-shaped teeth are formed on the outer periphery of the planetary gear.

[0005] An internal gear is constructed by rotatably fitting multiple pins (roller pins) that form the internal teeth into the inner circumferential surface of a gear body (internal gear body), which also serves as the housing. In a planetary gear, multiple inner pin holes (inner roller holes) are formed at appropriate intervals along the circumferential direction, into which inner pins and inner rollers are inserted. The inner pins are connected to a support at one axial end, and the support is rotatably supported in the housing via crossed roller bearings. This gear assembly can be used as a gear assembly that removes the planetary gear from the support by rotating the internal gear relative to its rotational component.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2003-74646 Summary of the Invention

[0009] In the aforementioned related technologies, for example, with the long-term use of gear devices, if the lubricant is not sufficiently distributed to different parts, it may lead to adverse conditions such as a decrease in the transmission efficiency of the gear device.

[0010] The purpose of this disclosure is to provide an internal meshing planetary gear device that is less prone to adverse effects such as a decrease in transmission efficiency.

[0011] Solutions for solving technical problems

[0012] An embodiment of this disclosure of an internal meshing planetary gear device includes a bearing member, an internal gear, a planetary gear, and a plurality of inner pins. The bearing member has an outer ring, an inner ring disposed inside the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring. The inner ring is supported to be rotatable relative to the outer ring about a rotation axis. The internal gear has internal teeth and is fixed to the outer ring. The planetary gear has external teeth that partially mesh with the internal teeth. The plurality of inner pins, when respectively inserted into a plurality of inner pin holes formed in the planetary gear, revolve within the inner pin holes and rotate relative to the internal gear. The inner ring includes a first inner ring and a second inner ring that are opposite each other in a direction parallel to the rotation axis and whose opposing surfaces are in contact with each other. The first inner ring has a plurality of retaining holes through which the plurality of inner pins respectively pass in a direction parallel to the rotation axis. Each of the plurality of inner pins is held in the inner ring in a rotatable state.

[0013] Invention Effects

[0014] According to embodiments of this disclosure, an internal meshing planetary gear device is provided that is less prone to adverse effects such as a decrease in transmission efficiency. Attached Figure Description

[0015] Figure 1 This is a perspective view showing the schematic structure of an actuator, including the internal meshing planetary gear mechanism with its basic structure.

[0016] Figure 2 This is a schematic exploded perspective view of the aforementioned internal meshing planetary gear device as seen from the output side of the rotating shaft.

[0017] Figure 3 This is a schematic cross-sectional view of the aforementioned internal meshing planetary gear assembly.

[0018] Figure 4 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 Sectional view along line A1-A1.

[0019] Figure 5A This is a perspective view of the planetary gears of the aforementioned internal meshing planetary gear assembly, shown as a single unit.

[0020] Figure 5B This is a front view of the planetary gears of the aforementioned internal meshing planetary gear assembly, shown as a single unit.

[0021] Figure 6A This is a perspective view of the bearing component of the aforementioned internal meshing planetary gear assembly.

[0022] Figure 6B This is a front view showing the bearing component of the aforementioned internal meshing planetary gear assembly.

[0023] Figure 7A This is a perspective view of the eccentric shaft of the aforementioned internal meshing planetary gear device.

[0024] Figure 7B This is a front view of the eccentric shaft of the aforementioned internal meshing planetary gear assembly, shown as a single unit.

[0025] Figure 8A This is a perspective view of the support body of the aforementioned internal meshing planetary gear device.

[0026] Figure 8B This is a front view of the support body of the aforementioned internal meshing planetary gear device, shown as a single unit.

[0027] Figure 9 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 A magnified view of region Z1.

[0028] Figure 10 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 Sectional view along line B1-B1.

[0029] Figure 11 This is a schematic cross-sectional view of the internal meshing planetary gear device of Embodiment 1.

[0030] Figure 12 This is a side view of the aforementioned internal meshing planetary gear device, viewed from the output side of the rotating shaft.

[0031] Figure 13 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 11 Sectional view along line A1-A1.

[0032] Figure 14 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 11 Sectional view along line B1-B1 and its enlarged portion.

[0033] Figure 15 This is a schematic cross-sectional view of the main parts of the aforementioned internal meshing planetary gear mechanism.

[0034] Figure 16 This is a schematic cross-sectional view of the main part of the aforementioned internal meshing planetary gear assembly, and a diagram schematically showing the path of the lubricant.

[0035] Figure 17 This is a schematic cross-sectional view of a wheel assembly using the aforementioned internal meshing planetary gear system.

[0036] Figure 18A This is a schematic cross-sectional view of the main parts of the internal meshing planetary gear device in a variation of Embodiment 1.

[0037] Figure 18B This is a schematic cross-sectional view of the main parts of the internal meshing planetary gear device in a variation of Embodiment 1.

[0038] Figure 19A This is a schematic cross-sectional view of the main parts of the internal meshing planetary gear device in Embodiment 2.

[0039] Figure 19B This shows the main parts of the aforementioned internal meshing planetary gear mechanism. Figure 19A Sectional view along line A1-A1.

[0040] Figure 20 This is a schematic cross-sectional view of the main part of the aforementioned internal meshing planetary gear assembly, and a diagram schematically showing the path of the lubricant. Detailed Implementation

[0041] (Basic Structure)

[0042] (1) Summary

[0043] The following is for reference Figures 1-3 This section provides an overview of the internal meshing planetary gear device 1 with its basic structure. The accompanying drawings, which are used in the embodiments of this disclosure, are schematic diagrams, and the size and thickness ratios of the various components shown may not reflect actual dimensional ratios. For example, Figures 1-3 The tooth shape, size, and number of teeth of the inner tooth 21 and the outer tooth 31 are merely schematic representations for illustrative purposes, and their main purpose is not limited to the shapes shown in the illustrations.

[0044] The internal meshing planetary gear assembly 1 (hereinafter also simply referred to as "gear assembly 1") of this basic structure is a gear assembly including an internal gear 2, a planetary gear 3, and multiple inner pins 4. In this gear assembly 1, the planetary gear 3 is arranged inside the annular internal gear 2, and an eccentric bearing 5 is arranged inside the planetary gear 3. The eccentric bearing 5 has an inner eccentric ring 51 and an outer eccentric ring 52, the inner eccentric ring 51 surrounding a ring from the center C1 of the inner eccentric ring 51 (see reference). Figure 3 The rotation axis Ax1 is deviated (refer to) Figure 3 The planetary gear 3 oscillates due to the rotation (eccentric motion) of the eccentric inner ring 51. The inner ring 51 of the eccentric gear rotates about the rotation axis Ax1, for example, by the rotation of the eccentric shaft 7 inserted into the inner ring 51. Furthermore, the internal meshing planetary gear device 1 also includes a bearing member 6 having an outer ring 62 and an inner ring 61. The inner ring 61 is disposed inside the outer ring 62 and is supported so that it can rotate relative to the outer ring 62.

[0045] The internal gear 2 has internal teeth 21 and is fixed to the outer ring 62. Specifically, in this basic structure, the internal gear 2 has an annular gear body 22 and multiple pins 23. The multiple pins 23 are held in a rotatable state on the inner circumferential surface 221 of the gear body 22, forming the internal teeth 21. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. That is, inside the internal gear 2, the planetary gear 3 is tangent to the internal gear 2, becoming a part of the external teeth 31 meshing with a part of the internal teeth 21. In this state, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates, and the meshing position of the internal teeth 21 and the external teeth 31 moves along the circumference of the internal gear 2, generating a relative rotation between the two gears (internal gear 2 and planetary gear 3) corresponding to the difference in the number of teeth between the planetary gear 3 and the internal gear 2. Here, if the internal gear 2 is fixed, the planetary gear 3 rotates (rotates) along with the relative rotation of the two gears. As a result, a rotational output that is reduced in speed at a relatively high reduction ratio is obtained from planetary gear 3, corresponding to the difference in the number of teeth between the two gears.

[0046] This gear device 1 is used in such a way that the rotation of the planetary gear 3, corresponding to its rotational component, is taken out as, for example, the rotation of an output shaft integrated with the inner ring 61 of the bearing member 6. Thus, the gear device 1 functions as a gear device with a relatively high reduction ratio, using the eccentric shaft 7 as the input side and the output shaft as the output side. Therefore, in this basic structure of the gear device 1, multiple inner pins 4 are used to connect the planetary gear 3 to the inner ring 61 in order to transmit the rotation of the planetary gear 3, corresponding to its rotational component, to the inner ring 61 of the bearing member 6. The multiple inner pins 4, when respectively inserted into multiple inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 and rotate relative to the internal gear 2. That is, the inner pin holes 32 have a diameter larger than the inner pins 4, allowing the inner pins 4 to revolve within the inner pin holes 32 while inserted. Furthermore, the oscillating component of the planetary gear 3, i.e., the revolving component of the planetary gear 3, is absorbed through the interlocking of the inner pin holes 32 of the planetary gear 3 and the inner pins 4. In other words, the multiple inner pins 4 revolve within the multiple inner pin holes 32, thereby absorbing the oscillation component of the planetary gear 3. Therefore, through the multiple inner pins 4, the rotation (rotation component) of the planetary gear 3, excluding the oscillation component (revolution component), is transmitted to the inner ring 61 of the bearing member 6.

[0047] However, in this gear device 1, the inner pin 4 revolves within the inner pin hole 32 of the planetary gear 3, and simultaneously transmits the rotation of the planetary gear 3 to multiple inner pins 4. Therefore, as a first linking technique, it is known to use an inner roller mounted on the inner pin 4 so that it can rotate around the inner pin 4 as an axis. That is, in the first linking technique, the inner pin 4 is held in a state where it is pressed into the inner ring 61 (or a bracket integrated with the inner ring 61), and when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 slides relative to the inner circumferential surface 321 of the inner pin hole 32. Therefore, as a first linking technique, an inner roller is used to reduce the loss caused by the frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4. However, if the structure includes an inner roller as in the first linking technique, the inner pin hole 32 needs to have a diameter that allows the inner pin 4 with the inner roller to revolve, making miniaturization of the inner pin hole 32 difficult. When miniaturization of the inner pin hole 32 is difficult, it hinders the miniaturization of the planetary gear 3 (especially the reduction of its diameter), and even hinders the miniaturization of the gear assembly 1 as a whole. The gear assembly 1 of this basic structure can provide an internal meshing planetary gear assembly 1 that is easily miniaturized through the following structure.

[0048] That is, such as Figures 1-3 As shown, the gear assembly 1 of this basic structure includes a bearing member 6, an internal gear 2, a planetary gear 3, and a plurality of inner pins 4. The bearing member 6 has an outer ring 62 and an inner ring 61 disposed inside the outer ring 62. The inner ring 61 is supported so as to be rotatable relative to the outer ring 62. The internal gear 2 has internal teeth 21 and is fixed to the outer ring 62. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. The plurality of inner pins 4, when respectively inserted into a plurality of inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 and rotate relative to the internal gear 2. Here, each of the plurality of inner pins 4 is held in the inner ring 61 in a state that allows it to rotate on its own axis. Furthermore, each of the plurality of inner pins 4 has at least a portion disposed at the same position as the bearing member 6 in the axial direction.

[0049] According to this configuration, each of the multiple inner pins 4 is held in the inner ring 61 in a rotatable state, so that when the inner pins 4 revolve within the inner pin holes 32, the inner pins 4 themselves can rotate. Therefore, even without using inner rollers mounted on the inner pins 4 and rotatable around the inner pins 4, losses caused by frictional resistance between the inner circumferential surface 321 of the inner pin holes 32 and the inner pins 4 can be reduced. Therefore, in the gear assembly 1 of this basic structure, it is not necessary to provide inner rollers, thus having the advantage of easy miniaturization. Moreover, each of the multiple inner pins 4 is at least partially arranged in the same position as the bearing member 6 in the axial direction, thus the size of the gear assembly 1 in the axial direction of the bearing member 6 can be reduced. That is, compared with the structure in which the bearing member 6 and the inner pins 4 are arranged side by side (opposite) in the axial direction of the bearing member 6, in the gear assembly 1 of this basic structure, the size of the gear assembly 1 in the axial direction can be reduced, thereby contributing to further miniaturization (thinning) of the gear assembly 1.

[0050] Furthermore, if the size of the planetary gear 3 is the same as that of the first associated technology described above, then compared with the first associated technology described above, for example, it is possible to increase the number of inner pins 4 to make the rotation transmission smoother, or to make the inner pins 4 thicker to increase strength.

[0051] Furthermore, in this gear assembly 1, the inner pins 4 need to revolve within the inner pin holes 32 of the planetary gear 3. Therefore, as a second correlation technique, there are cases where multiple inner pins 4 are held only by the inner ring 61 (or a bracket integrated with the inner ring 61). According to the second correlation technique, it is difficult to improve the centering accuracy of the multiple inner pins 4, and poor centering may lead to adverse conditions such as vibration and decreased transmission efficiency. That is, the multiple inner pins 4 revolve within the inner pin holes 32 and rotate relative to the internal gear 2, thereby transmitting the rotational component of the planetary gear 3 to the inner ring 61 of the bearing member 6. At this time, if the centering accuracy of the multiple inner pins 4 is insufficient and the rotation axis of the multiple inner pins 4 deviates or tilts relative to the rotation axis of the inner ring 61, it becomes a state of poor centering, which may lead to adverse conditions such as vibration and decreased transmission efficiency. The gear assembly 1 of this basic structure can provide an internal meshing planetary gear assembly 1 that is less prone to adverse conditions caused by poor centering of the multiple inner pins 4 through the following structure.

[0052] That is, such as Figures 1-3As shown, the gear assembly 1 of this basic structure includes an internal gear 2, a planetary gear 3, multiple inner pins 4, and a support body 8. The internal gear 2 has an annular gear body 22 and multiple pins 23. The multiple pins 23 are held in a rotatable state on the inner circumferential surface 221 of the gear body 22 to form internal teeth 21. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. The multiple inner pins 4, when respectively inserted into multiple inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 and rotate relative to the gear body 22. The support body 8 is annular and supports the multiple inner pins 4. Here, the support body 8 is positionally restricted by contacting the multiple pins 23 with its outer circumferential surface 81.

[0053] According to this configuration, the multiple inner pins 4 are supported by an annular support body 8. Therefore, the multiple inner pins 4 are bound together by the support body 8, suppressing relative deviation and tilting of the multiple inner pins 4. Furthermore, the outer peripheral surface 81 of the support body 8 contacts the multiple pins 23, thereby restricting the position of the support body 8. In short, by centering the support body 8 using the multiple pins 23, it is also possible to center the multiple inner pins 4 supported by the support body 8 using the multiple pins 23. Therefore, the gear device 1 with this basic structure easily achieves improved centering accuracy of the multiple inner pins 4, and has the advantage of minimizing defects caused by poor centering of the multiple inner pins 4.

[0054] In addition, such as Figure 1 As shown, the gear assembly 1 and the drive source 101 together constitute the actuator 100 of this basic structure. In other words, the actuator 100 of this basic structure includes the gear assembly 1 and the drive source 101. The drive source 101 generates a driving force for oscillating the planetary gear 3. Specifically, the drive source 101 causes the eccentric shaft 7 to rotate about the rotation axis Ax1, thereby causing the planetary gear 3 to oscillate.

[0055] (2) Definition

[0056] In this embodiment of the disclosure, "annular" refers to a shape that forms a ring (circle) of enclosed space (area) on the inside, at least when viewed from above. It is not limited to a circular shape (annular) that is perfectly round when viewed from above; for example, it can also be an elliptical shape or a polygonal shape. Furthermore, even shapes with a bottom, such as a cup shape, are included in "annular" as long as their peripheral walls are annular.

[0057] In this embodiment, "playing" refers to a state where the inner pin 4 is fitted with a clearance, and the inner pin hole 32 is a hole for the inner pin 4 to play. That is, the inner pin 4 is inserted into the inner pin hole 32 with sufficient space (clearance) between it and the inner circumferential surface 321 of the inner pin hole 32. In other words, the diameter of at least the portion of the inner pin 4 inserted into the inner pin hole 32 is smaller (thinner) than the diameter of the inner pin hole 32. Therefore, the inner pin 4, when inserted into the inner pin hole 32, can move within the inner pin hole 32, that is, it can move relative to the center of the inner pin hole 32. Thus, the inner pin 4 can revolve within the inner pin hole 32. However, it is not necessary to ensure a clearance as a void between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4; for example, a fluid such as liquid can be filled into the clearance.

[0058] In this embodiment of the disclosure, "revolution" refers to an object rotating around an axis other than the central axis passing through the object's center (center of gravity). When an object revolves, its center moves along a revolution path centered on the rotation axis. Therefore, for example, when an object rotates around an eccentric axis parallel to the central axis passing through its center (center of gravity), the object revolves around the eccentric axis. As an example, the inner pin 4 revolves around an axis of rotation passing through the center of the inner pin hole 32, thus revolving within the inner pin hole 32.

[0059] Additionally, in embodiments of this disclosure, sometimes one side of the rotating shaft Ax1 ( Figure 3 The left side of the axis (Ax1) is called the "input side", and the other side of the axis (Ax1) is called the "input side". Figure 3 The right side of the output is called the "output side". Figure 3 In the example, rotation is imparted to the rotating body (eccentric inner ring 51) from the "input side" of the rotating shaft Ax1, and rotation of multiple inner pins 4 (inner ring 61) is taken out from the "output side" of the rotating shaft Ax1. However, "input side" and "output side" are merely labels given for illustrative purposes, and their purpose is not to limit the positional relationship of input and output as observed from the gear device 1.

[0060] In this embodiment of the disclosure, the "rotation axis" refers to a virtual axis (straight line) that serves as the center of rotational motion of the rotating body. That is, the rotation axis Ax1 is a virtual axis without a physical component. The inner ring 51 of the eccentric body rotates around the rotation axis Ax1.

[0061] In this embodiment of the disclosure, "internal teeth" and "external teeth" refer to a collection (group) of multiple "teeth" rather than a single "tooth". That is, the internal teeth 21 of the internal gear 2 are composed of a collection of multiple teeth disposed on the inner circumferential surface 221 of the internal gear 2 (gear body 22). Similarly, the external teeth 31 of the planetary gear 3 are composed of a collection of multiple teeth disposed on the outer circumferential surface of the planetary gear 3.

[0062] (3) Structure

[0063] The following is for reference Figures 1 to 8B This section describes the detailed structure of the internal meshing planetary gear device 1 of this basic structure.

[0064] Figure 1 This is a perspective view showing the schematic structure of the actuator 100, which includes the gear mechanism 1. Figure 1 The drive source 101 is schematically shown in the diagram. Figure 2 This is a schematic exploded perspective view of the gear device 1 as seen from the output side of the rotating shaft Ax1. Figure 3 This is a schematic cross-sectional view of gear assembly 1. Figure 4 yes Figure 3 A sectional view along line A1-A1. Wherein... Figure 4 In the section, for components other than the eccentric shaft 7, although it is also a cross-section, the section lines are omitted. Furthermore, in... Figure 4 The inner circumferential surface 221 of the gear body 22 is omitted from the illustration. Figure 5A and Figure 5B The perspective view and front view of planetary gear 3 are shown as a single unit. Figure 6A and Figure 6B The three-dimensional view and front view of bearing component 6 are shown as a single unit. Figure 7A and Figure 7B The diagram shows a three-dimensional view and a front view of the eccentric shaft 7 as a single unit. Figure 8A and Figure 8B The support body 8 is shown as a single unit, including a perspective view and a front view.

[0065] (3.1) Overall Structure

[0066] like Figures 1-3 As shown, the gear assembly 1 of this basic structure includes an internal gear 2, a planetary gear 3, multiple inner pins 4, an eccentric bearing 5, a bearing component 6, an eccentric shaft 7, and a support body 8. Furthermore, in this basic structure, the gear assembly 1 also includes a first bearing 91, a second bearing 92, and a housing 10. In this basic structure, the internal gear 2, planetary gear 3, multiple inner pins 4, eccentric bearing 5, bearing component 6, eccentric shaft 7, and support body 8, which are structural elements of the gear assembly 1, are made of metals such as stainless steel, cast iron, structural carbon steel, chromium-molybdenum steel, phosphor bronze, or aluminum bronze. The metals mentioned here include metals that have undergone surface treatments such as nitriding.

[0067] Furthermore, in this basic structure, as an example of gear device 1, an internally tangent planetary gear device with cycloidal tooth profile is illustrated. That is, the gear device 1 of this basic structure includes an internally tangent planetary gear 3 with cycloidal curved tooth profile.

[0068] Furthermore, in this basic structure, as an example, the gear device 1 is used with the gear body 22 of the internal gear 2 and the outer ring 62 of the bearing member 6 fixed to a fixed member such as the housing 10. Thus, 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 (housing 10, etc.).

[0069] Furthermore, in this basic structure, when the gear device 1 is used in the actuator 100, a rotational force is applied to the eccentric shaft 7 as input and taken out as output rotational force from the output shaft integrated with the inner ring 61 of the bearing member 6. That is, the gear device 1 operates with the rotation of the eccentric shaft 7 as input rotation and the rotation of the output shaft 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 reduction ratio relative to the input rotation can be obtained.

[0070] The drive source 101 is a power source such as a motor (electric motor). The power generated by the drive source 101 is transmitted to the eccentric shaft 7 in the gear assembly 1. Specifically, the drive source 101 is connected to the eccentric shaft 7 via an input shaft, and the power generated by the drive source 101 is transmitted to the eccentric shaft 7 via the input shaft. Thus, the drive source 101 can rotate the eccentric shaft 7.

[0071] Furthermore, in the gear device 1 of this basic structure, such as Figure 3 As shown, 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 eccentric shaft 7, which is given input rotation, and the output-side rotation axis Ax1 is the rotation center of the inner ring 61 (and output shaft), which generates output rotation. That is, in the gear device 1, it is possible to obtain output rotation that is reduced in speed by a relatively high reduction ratio by rotating coaxially relative to the input.

[0072] like Figure 4 As shown, the internal gear 2 is an annular component with internal teeth 21. In this basic structure, the internal gear 2 has an annular shape, at least its inner circumferential surface being a perfect circle when viewed from above. Internal teeth 21 are formed along the circumferential direction of the annular internal gear 2 on its inner circumferential surface. All teeth constituting the internal teeth 21 are of the same shape and are evenly spaced throughout the entire circumferential region of the inner circumferential surface of the internal gear 2. That is, the pitch circle of the internal teeth 21 is a perfect circle when viewed from above. The center of the pitch circle of the internal teeth 21 is located on the rotation axis Ax1. Furthermore, the internal gear 2 has a predetermined thickness along the direction of the rotation axis Ax1. The tooth directions of the internal teeth 21 are all parallel to the rotation axis Ax1. The dimension of the tooth direction of the internal teeth 21 is slightly smaller than that in the thickness direction of the internal gear 2.

[0073] Here, as described above, the internal gear 2 has an annular (ring-shaped) gear body 22 and multiple pins 23. The multiple pins 23 are held in a rotatable state on the inner circumferential surface 221 of the gear body 22, forming the internal teeth 21. In other words, the multiple pins 23 function as multiple teeth constituting the internal teeth 21. Specifically, on the inner circumferential surface 221 of the gear body 22, as... Figure 2 Multiple grooves are formed throughout the circumferential region. All grooves are of the same shape and are equally spaced. All grooves are parallel to the rotation axis Ax1 and extend along the entire thickness of the gear body 22. Multiple pins 23 are fitted into the grooves and assembled to the gear body 22. Each pin 23 is held within its groove in a position to rotate. Furthermore, the gear body 22 (together with the outer ring 62) is fixed to the housing 10. Therefore, multiple fixing holes 222 are formed in the gear body 22 for fixing.

[0074] like Figure 4 As shown, the planetary gear 3 is an annular component with external teeth 31. In this basic structure, the planetary gear 3 has an annular shape, at least its outer circumferential surface being a perfect circle when viewed from above. External teeth 31 are formed on the outer circumferential surface of the annular planetary gear 3 along the circumferential direction of the planetary gear 3. All teeth constituting the external teeth 31 are of the same shape and are evenly spaced throughout the entire circumferential region of the outer circumferential surface of the planetary gear 3. That is, the pitch circle of the external teeth 31 is a perfect circle when viewed from above. The center C1 of the pitch circle of the external teeth 31 is located at a distance ΔL from the rotation axis Ax1 (refer to...). Figure 4 The planetary gear 3 has a defined thickness along the direction of the rotation axis Ax1. The external teeth 31 are formed along the entire length of the planetary gear 3 in the thickness direction. The tooth direction of the external teeth 31 is parallel to the rotation axis Ax1. Unlike the internal gear 2, the external teeth 31 and the main body of the planetary gear 3 are integrally formed from a single metal component.

[0075] Here, the planetary gear 3 is combined with the eccentric bearing 5 and the eccentric shaft 7. Specifically, the planetary gear 3 has a circular opening 33. The opening 33 is a hole that passes through the planetary gear 3 along its thickness direction. Viewed from above, the center of the opening 33 coincides with the center of the planetary gear 3, and the inner circumferential surface of the opening 33 (the inner circumferential surface of the planetary gear 3) is concentric with the pitch circle of the external tooth 31. The eccentric bearing 5 is housed within the opening 33 of the planetary gear 3. Furthermore, the eccentric bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3 by inserting the eccentric shaft 7 into the inner ring 51 of the eccentric bearing 5. With the planetary gear 3 combined with the eccentric bearing 5 and the eccentric shaft 7, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates around the rotation axis Ax1.

[0076] The planetary gear 3, thus configured, is positioned inside the internal gear 2. Viewed from above, the planetary gear 3 is one size smaller than the internal gear 2, allowing it to oscillate inside the internal gear 2 when combined with it. External teeth 31 are formed on the outer circumferential surface of the planetary gear 3, while internal teeth 21 are formed on the inner circumferential surface of the internal gear 2. Therefore, with the planetary gear 3 positioned inside the internal gear 2, the external teeth 31 and the internal teeth 21 are opposite each other.

[0077] Furthermore, the pitch circle of the external tooth 31 is one rotation smaller than that of the internal tooth 21. Also, when the planetary gear 3 is internally tangent to the internal gear 2, the center C1 of the pitch circle of the external tooth 31 is offset by ΔL (refer to the rotation axis Ax1) from the center of the pitch circle of the internal tooth 21. Figure 4 Therefore, the external teeth 31 and the internal teeth 21 are at least partially opposed with a gap, and there is no overall meshing in the circumferential direction. However, the planetary gear 3 oscillates (revolves) around the rotation axis Ax1 inside the internal gear 2, so the external teeth 31 and the internal teeth 21 partially mesh. That is, by the oscillation of the planetary gear 3 around the rotation axis Ax1, as... Figure 4 As shown, a portion of the teeth constituting the external tooth 31 meshes with a portion of the teeth constituting the internal tooth 21. As a result, in the gear assembly 1, a portion of the external tooth 31 can mesh with a portion of the internal tooth 21.

[0078] Here, the number of teeth of the internal gear 21 in the internal gear 2 is N more than the number of teeth of the external gear 31 in the planetary gear 3 (N is a positive integer). In this basic structure, as an example, N is "1", so the number of teeth of the planetary gear 3 (external teeth 31) is "1" more than the number of teeth of the internal gear 2 (internal teeth 21). This 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 unit 1.

[0079] Furthermore, in this basic structure, as an example, the thickness of the planetary gear 3 is smaller than the thickness of the gear body 22 in the internal gear 2. In addition, the dimension of the external tooth 31 in the tooth direction (parallel to the rotation axis Ax1) is smaller than the dimension of the internal tooth 21 in the tooth direction (parallel to the rotation axis Ax1). In other words, in the direction parallel to the rotation axis Ax1, the external tooth 31 is contained within the tooth direction of the internal tooth 21.

[0080] In this basic structure, as described above, the rotation of the planetary gear 3, corresponding to its rotational component, is taken as the rotation (output rotation) of the output shaft integrated with the inner ring 61 of the bearing member 6. Therefore, the planetary gear 3 is connected to the inner ring 61 using multiple inner pins 4. Figure 5A and Figure 5BAs shown, the planetary gear 3 has multiple inner pin holes 32 for inserting multiple inner pins 4. The number of inner pin holes 32 is the same as the number of inner pins 4; in this basic structure, for example, there are 18 inner pin holes 32 and 18 inner pins 4. Each inner pin hole 32 is a hole that opens in a circular shape and passes through the planetary gear 3 along its thickness direction. The multiple (here, 18) inner pin holes 32 are arranged at equal intervals along the circumferential direction on a virtual circle concentric with the opening 33.

[0081] Multiple inner pins 4 are components that connect the planetary gear 3 to the inner ring 61 of the bearing component 6. Each of the multiple inner pins 4 is cylindrical. The diameter and length of the multiple inner pins 4 are the same. The diameter of the inner pin 4 is one size smaller than the diameter of the inner pin hole 32. Thus, the inner pin 4 is inserted into the inner pin hole 32 (see reference) with sufficient space (clearance) between it and the inner circumferential surface 321 of the inner pin hole 32. Figure 4 ).

[0082] The bearing component 6 is a part having an outer ring 62 and an inner ring 61 and used to extract the output of the gear device 1 as the rotation of the inner ring 61 relative to the outer ring 62. In addition to the outer ring 62 and the inner ring 61, the bearing component 6 also has a plurality of rolling elements 63 (see reference). Figure 3 ).

[0083] like Figure 6A and Figure 6B As shown, both the outer ring 62 and the inner ring 61 are annular components. Both the outer ring 62 and the inner ring 61 are circular when viewed from above. The inner ring 61 is smaller than the outer ring 62 and is positioned inside the outer ring 62. Here, the inner diameter of the outer ring 62 is larger than the outer diameter of the inner ring 61, thus creating a gap between the inner circumferential surface of the outer ring 62 and the outer circumferential surface of the inner ring 61.

[0084] The inner ring 61 has a plurality of retaining holes 611 for inserting a plurality of inner pins 4. The number of retaining holes 611 is the same as the number of inner pins 4; in this basic structure, for example, 18 retaining holes 611 are provided. Figure 6A and Figure 6B As shown, each of the plurality of retaining holes 611 is a circularly shaped opening that penetrates the inner ring 61 along the thickness direction. The plurality of (here, 18) retaining holes 611 are arranged at equal intervals along the circumferential direction on a virtual circle concentric with the outer periphery of the inner ring 61. The diameter of the retaining hole 611 is greater than or equal to the diameter of the inner pin 4 but smaller than the diameter of the inner pin hole 32.

[0085] Furthermore, the inner ring 61 is integrated with the output shaft, and the rotation of the inner ring 61 is taken as the rotation of the output shaft. Therefore, a plurality of output-side mounting holes 612 for mounting the output shaft are formed in the inner ring 61 (see reference). Figure 2In this basic structure, a plurality of output-side mounting holes 612 are arranged on a virtual circle that is inside the plurality of retaining holes 611 and concentric with the outer periphery of the inner ring 61.

[0086] The outer ring 62 is fixed together with the gear body 22 of the internal gear 2 to the housing 10 and other fixing components. Therefore, multiple through holes 621 for fixing are formed in the outer ring 62. Specifically, as shown... Figure 3 As shown, the outer ring 62 is fixed to the housing 10 with the gear body 22 sandwiched between it and the housing 10 by screws (bolts) 60 for fixing through the through hole 621 and the fixing hole 222 of the gear body 22.

[0087] Multiple rolling elements 63 are disposed in the gap between the outer ring 62 and the inner ring 61. The multiple rolling elements 63 are arranged side by side along the circumferential direction of the outer ring 62. All of the multiple rolling elements 63 are metal parts of the same shape and are equally spaced throughout the entire circumferential region of the outer ring 62.

[0088] In this basic structure, as an example, the bearing member 6 is a crossed roller bearing. That is, the bearing member 6 has cylindrical rollers as rolling elements 63. Furthermore, the axis of the cylindrical rolling element 63 is inclined at 45 degrees with respect to a plane orthogonal to the rotation axis Ax1, and is orthogonal to the outer circumference of the inner ring 61. In addition, a pair of adjacent rolling elements 63 in the circumferential direction of the inner ring 61 are arranged in an axially orthogonal orientation. In such a bearing member 6 composed of crossed roller bearings, radial loads, thrust loads (in the direction along the rotation axis Ax1), and bending forces (bending moment loads) relative to the rotation axis Ax1 can be easily withstood. Moreover, by means of a single bearing member 6, these three types of loads can be withstood, thereby ensuring the required rigidity.

[0089] like Figure 7A and Figure 7B As shown, the eccentric shaft 7 is a cylindrical component. The eccentric shaft 7 has a central portion 71 and an eccentric portion 72. The central portion 71 is cylindrical, with at least its outer circumferential surface being perfectly circular when viewed from above. The center (central axis) of the central portion 71 coincides with the rotation axis Ax1. The eccentric portion 72 is disk-shaped, with at least its outer circumferential surface being perfectly circular when viewed from above. The center (central axis) of the eccentric portion 72 coincides with a center C1 offset from the rotation axis Ax1. Here, the distance ΔL between the rotation axis Ax1 and the center C1 (refer to...) Figure 7B The eccentricity of the eccentric portion 72 relative to the central portion 71 is defined as the amount of eccentricity. The eccentric portion 72 has a flange shape that protrudes from the outer circumference of the central portion 71 at its center in the longitudinal direction (axial direction). According to the above structure, for the eccentric shaft 7, the eccentric portion 72 performs eccentric motion by rotating the central portion 71 around the rotation axis Ax1.

[0090] In this basic structure, the central shaft 71 and the eccentric shaft 72 are integrally formed from a single metal component, thereby achieving a seamless eccentric shaft 7. This eccentric shaft 7, with its shape, is combined with the eccentric bearing 5 in the planetary gear 3. Therefore, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates around the rotation axis Ax1, with the planetary gear 3 having the eccentric bearing 5 and the eccentric shaft 7 combined.

[0091] Furthermore, the eccentric shaft 7 has a through hole 73 that extends through the shaft center portion 71 along the axial direction (length direction). The through hole 73 opens in a circular shape at both end faces of the shaft center portion 71 in the axial direction. The center (central axis) of the through hole 73 coincides with the rotation axis Ax1. Cables such as power lines and signal lines can pass through the through hole 73.

[0092] Furthermore, in this basic structure, a rotational force is applied as an input from the drive source 101 to the eccentric shaft 7. Therefore, a plurality of input-side mounting holes 74 are formed on the eccentric shaft 7 for mounting an input shaft connected to the drive source 101 (see reference). Figure 7A and Figure 7B In this basic structure, a plurality of input-side mounting holes 74 are arranged around the through hole 73 on one end face of the axial part 71 and on a virtual circle concentric with the through hole 73.

[0093] The eccentric bearing 5 is a component having an outer eccentric ring 52 and an inner eccentric ring 51, absorbing the rotational component of the eccentric shaft 7, and transmitting only the oscillating component (revolutionary component) of the eccentric shaft 7 to the planetary gear 3, excluding the rotational component of the eccentric shaft 7. In addition to the outer eccentric ring 52 and the inner eccentric ring 51, the eccentric bearing 5 also has multiple rolling elements 53 (see reference). Figure 3 ).

[0094] Both the outer eccentric ring 52 and the inner eccentric ring 51 are annular components. Both are perfectly circular rings when viewed from above. The inner eccentric ring 51 is smaller than the outer eccentric ring 52 and is positioned inside the outer eccentric ring 52. Here, the inner diameter of the outer eccentric ring 52 is larger than the outer diameter of the inner eccentric ring 51, thus creating a gap between the inner circumferential surface of the outer eccentric ring 52 and the outer circumferential surface of the inner eccentric ring 51.

[0095] Multiple rolling elements 53 are disposed in the gap between the outer ring 52 and the inner ring 51 of the eccentric outer ring. The multiple rolling elements 53 are arranged side-by-side along the circumferential direction of the outer ring 52. All multiple rolling elements 53 are metal parts of the same shape and are evenly spaced throughout the entire circumferential region of the outer ring 52. In this basic structure, as an example, the eccentric bearing 5 is constructed using a deep groove ball bearing that uses balls as rolling elements 53.

[0096] Here, the inner diameter of the inner ring 51 of the eccentric shaft 7 matches the outer diameter of the eccentric portion 72 in the eccentric shaft 7. The eccentric bearing 5 is assembled with the eccentric shaft 7 with the eccentric portion 72 inserted into the inner ring 51 of the eccentric shaft 7. Furthermore, the outer diameter of the outer ring 52 of the eccentric shaft 7 matches the inner diameter (diameter) of the opening 33 of the planetary gear 3. The eccentric bearing 5 is assembled with the planetary gear 3 with the outer ring 52 of the eccentric shaft 7 embedded in the opening 33 of the planetary gear 3. In other words, the eccentric bearing 5, which is mounted on the eccentric portion 72 of the eccentric shaft 7, is housed in the opening 33 of the planetary gear 3.

[0097] Furthermore, in this basic structure, as an example, the width direction (parallel to the rotation axis Ax1) of the inner ring 51 of the eccentric bearing 5 is approximately the same as the thickness of the eccentric portion 72 of the eccentric shaft 7. The width direction (parallel to the rotation axis Ax1) of the outer ring 52 of the eccentric bearing is slightly smaller than the width direction of the inner ring 51. Moreover, the width direction of the outer ring 52 of the eccentric bearing is larger than the thickness of the planetary gear 3. Therefore, in the direction parallel to the rotation axis Ax1, the planetary gear 3 is contained within the area of ​​the eccentric bearing 5. On the other hand, the width direction of the outer ring 52 of the eccentric bearing is smaller than the tooth direction (parallel to the rotation axis Ax1) of the internal gear 21. Therefore, in the direction parallel to the rotation axis Ax1, the eccentric bearing 5 is contained within the area of ​​the internal gear 2.

[0098] With the eccentric bearing 5 and eccentric shaft 7 combined in the planetary gear 3, when the eccentric shaft 7 rotates, the inner ring 51 of the eccentric bearing 5 rotates around a rotation axis Ax1 that deviates from the center C1 of the inner ring 51 (eccentric motion). At this time, the rotational component of the eccentric shaft 7 is absorbed by the eccentric bearing 5. Therefore, through the eccentric bearing 5, the rotation of the eccentric shaft 7, except for its rotational component, i.e., only the oscillating component (revolutionary component) of the eccentric shaft 7, is transmitted to the planetary gear 3. Thus, with the planetary gear 3 combined with the eccentric bearing 5 and eccentric shaft 7, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates around the rotation axis Ax1.

[0099] like Figure 8A and Figure 8B As shown, the support body 8 is a component formed in a ring shape that supports a plurality of inner pins 4. The support body 8 has a plurality of support holes 82 into which the plurality of inner pins 4 are inserted respectively. The number of support holes 82 is the same as the number of inner pins 4; in this basic structure, as an example, 18 support holes 82 are provided. Figure 8A and Figure 8BAs shown, each of the plurality of support holes 82 is a circular opening that penetrates the support body 8 along the thickness direction. The plurality of (here, 18) support holes 82 are arranged at equal intervals along the circumferential direction on a virtual circle concentric with the outer peripheral surface 81 of the support body 8. The diameter of the support hole 82 is greater than or equal to the diameter of the inner pin 4 but smaller than the diameter of the inner pin hole 32. In this basic structure, as an example, the diameter of the support hole 82 is equal to the diameter of the retaining hole 611 formed in the inner ring 61.

[0100] like Figure 3 As shown, the support body 8 is arranged opposite the planetary gear 3 from one side (input side) of the rotation axis Ax1. Furthermore, the support body 8 functions to bind the multiple inner pins 4 by inserting them into the multiple support holes 82. In addition, the support body 8 is positionally restricted by contacting the outer peripheral surface 81 with the multiple pins 23. Thus, the support body 8 is centered using the multiple pins 23, and consequently, the multiple inner pins 4 supported on the support body 8 are also centered using the multiple pins 23. The support body 8 will be described in detail in the "(3.3) Support Body" section.

[0101] The first bearing 91 and the second bearing 92 are respectively mounted on the central portion 71 of the eccentric shaft 7. Specifically, as shown in the figure... Figure 3 As shown, the first bearing 91 and the second bearing 92 are mounted on both sides of the eccentric portion 72 of the shaft center portion 71 in a direction parallel to the rotation axis Ax1, sandwiching the eccentric portion 72. When viewed from the eccentric portion 72, the first bearing 91 is positioned on the input side of the rotation axis Ax1. When viewed from the eccentric portion 72, the second bearing 92 is positioned on the output side of the rotation axis Ax1. The first bearing 91 holds the eccentric shaft 7 so that it can rotate relative to the housing 10. The second bearing 92 holds the eccentric shaft 7 so that it can rotate relative to the inner ring 61 of the bearing member 6. Thus, the shaft center portion 71 of the eccentric shaft 7 is held rotatable at two locations on both sides of the eccentric portion 72 in a direction parallel to the rotation axis Ax1.

[0102] The housing 10 is cylindrical and has a flange 11 on the output side of the rotating shaft Ax1. Multiple mounting holes 111 are formed in the flange 11 for securing the housing 10 itself. Furthermore, a bearing hole 12 is formed on the end face of the rotating shaft Ax1 on the output side of the housing 10. The bearing hole 12 has a circular opening. The first bearing 91 is mounted to the housing 10 by inserting it into the bearing hole 12.

[0103] Furthermore, a plurality of threaded holes 13 are formed on the output side end face of the rotating shaft Ax1 of the housing 10 and around the bearing bore 12. The plurality of threaded holes 13 are used to fix the gear body 22 of the internal gear 2 and the outer ring 62 of the bearing member 6 to the housing 10. Specifically, the fixing screws 60 pass through the through hole 621 of the outer ring 62 and the fixing hole 222 of the gear body 22 and are tightened into the threaded holes 13, thereby fixing the gear body 22 and the outer ring 62 to the housing 10.

[0104] In addition, such as Figure 3 As shown, the gear assembly 1 of this basic structure also includes multiple oil seals 14, 15, 16, etc. Oil seal 14 is mounted on the input end of the rotating shaft Ax1 of the eccentric shaft 7, filling the gap between the housing 10 and the eccentric shaft 7 (core portion 71). Oil seal 15 is mounted on the output end of the rotating shaft Ax1 of the eccentric shaft 7, filling the gap between the inner ring 61 and the eccentric shaft 7 (core portion 71). Oil seal 16 is mounted on the output end face of the rotating shaft Ax1 of the bearing member 6, filling the gap between the inner ring 61 and the outer ring 62. The space sealed by these multiple oil seals 14, 15, 16 constitutes a lubricant retention space 17 (see reference). Figure 9 The lubricant retention space 17 includes the space between the inner ring 61 and the outer ring 62 of the bearing component 6. In addition, the lubricant retention space 17 houses a plurality of pins 23, a planetary gear 3, an eccentric bearing 5, a support body 8, a first bearing 91, and a second bearing 92, etc.

[0105] Furthermore, a lubricant is sealed in the lubricant holding space 17. The lubricant is liquid and can flow within the lubricant holding space 17. Therefore, during the use of the gear device 1, for example, the lubricant enters the meshing part between the internal teeth 21, which is composed of multiple pins 23, and the external teeth 31 of the planetary gear 3. The term "liquid" as used in this embodiment includes liquid or gel-like substances. The term "gel-like" as used herein refers to a state having intermediate properties between liquid and solid, including a colloid state composed of both a liquid phase and a solid phase. For example, the states of emulsion, where the dispersant is a liquid phase and the dispersed substance is a liquid phase, and suspension, where the dispersed substance is a solid phase, are called gels or sols and are included in the term "gel-like". Moreover, the state where the dispersant is a solid phase and the dispersed substance is a liquid phase is also included in the term "gel-like". In this basic structure, as an example, the lubricant is a liquid lubricating oil.

[0106] In the gear assembly 1 described above, a rotational force is applied as input to the eccentric shaft 7, which rotates around the rotation axis Ax1, causing the planetary gear 3 to oscillate (revolve) around the rotation axis Ax1. At this time, the planetary gear 3 oscillates internally to the internal gear 2, with a portion of its external teeth 31 meshing with a portion of its internal teeth 21. Therefore, the meshing position of the internal teeth 21 and external teeth 31 moves along the circumferential direction of the internal gear 2. This generates a relative rotation between the two gears (internal gear 2 and planetary gear 3) corresponding to the difference in the number of teeth between the planetary gear 3 and the internal gear 2. Furthermore, the rotation of the planetary gear 3 (its rotational component, excluding the oscillation component, of the planetary gear 3) is transmitted to the inner ring 61 of the bearing member 6 via multiple inner pins 4. As a result, a rotational output, reduced at a relatively high reduction ratio corresponding to the difference in the number of teeth between the two gears, can be obtained from the output shaft integrated into the inner ring 61.

[0107] However, in the gear device 1 of this embodiment, 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 relative to the input rotation in the gear device 1. That is, when the number of teeth of the internal gear 2 is set to "V1" and the number of teeth of the planetary gear 3 is set to "V2", the reduction ratio R1 is expressed by the following formula 1.

[0108] R1=V2 / (V1-V2)…(Formula 1)

[0109] In summary, the smaller the difference in the number of teeth (V1-V2) between the internal gear 2 and the planetary gear 3, the larger the reduction ratio R1. For example, the number of teeth V1 of the internal gear 2 is "52", and the number of teeth V2 of the planetary gear 3 is "51", with a difference in the number of teeth (V1-V2) of "1". Therefore, according to Equation 1 above, the reduction ratio R1 is "51". In this case, when viewed from the input side of the rotating shaft Ax1, if the eccentric shaft 7 rotates clockwise around the rotating shaft Ax1 for one full turn (360 degrees), then the inner ring 61 rotates counterclockwise around the rotating shaft Ax1 by the amount of the tooth difference "1" (approximately 7.06 degrees).

[0110] According to the gear device 1 of this basic structure, such a high reduction ratio R1 can be achieved by a combination of a primary gear (internal gear 2 and planetary gear 3).

[0111] In addition, the gear device 1 only needs to include at least an internal gear 2, a planetary gear 3, multiple internal pins 4, a bearing component 6, and a support body 8, and may also include, for example, a spline bushing as a structural element.

[0112] However, in cases where the input rotation, such as in the gear device 1 of this basic structure, is accompanied by eccentric motion and is a high-speed rotating side, vibration or other issues may occur if the weight balance of the rotating body undergoing high-speed rotation is not achieved. Therefore, a counterweight or similar device is sometimes used to achieve weight balance. That is, since the rotating body, composed of at least one of the inner ring 51 of the eccentric body and a component (eccentric shaft 7) that rotates together with the inner ring 51 of the eccentric body, undergoes eccentric motion at high speed, it is preferable to achieve weight balance of this rotating body relative to the rotation axis Ax1. In this basic structure, as... Figure 3 and Figure 4 As shown, the weight balance of the rotating body relative to the rotation axis Ax1 is achieved by providing a gap 75 in a part of the eccentric portion 72 of the eccentric shaft 7.

[0113] In summary, in this basic structure, weight reduction is achieved by thinning a portion of the rotating body (here, the eccentric shaft 7) without adding counterweights, thereby achieving weight balance of the rotating body relative to the rotation axis Ax1. That is, the gear assembly 1 of this basic structure includes an eccentric bearing 5 housed in the opening 33 formed in the planetary gear 3 and causing the planetary gear 3 to oscillate. The eccentric bearing 5 has an outer eccentric ring 52 and an inner eccentric ring 51 disposed inside the outer eccentric ring 52. The rotating body, composed of at least one of the inner eccentric ring 51 and a component that rotates together with the inner eccentric ring 51, has a gap 75 on a portion of the outer eccentric ring 52 at the center C1 side when viewed from the rotation axis Ax1 of the inner eccentric ring 51. In this basic structure, the eccentric shaft 7 is a "component that rotates together with the inner eccentric ring 51," equivalent to a "rotating body." Therefore, the gap 75 formed in the eccentric portion 72 of the eccentric shaft 7 is equivalent to the gap 75 of the rotating body. Figure 3 and Figure 4 As shown, the gap 75 is located on the side of the center C1 when viewed from the rotation axis Ax1, and thus plays a role in making the weight balance of the eccentric shaft 7 nearly equal from the rotation axis Ax1 to the circumferential direction.

[0114] More specifically, the gap 75 includes a recess formed on the inner circumferential surface of the through hole 73 that passes through the rotating body along the rotation axis Ax1 of the inner ring 51. That is, in this basic structure, the rotating body is the eccentric shaft 7, so the recess formed on the inner circumferential surface of the through hole 73 that passes through the eccentric shaft 7 along the rotation axis Ax1 functions as the gap 75. In this way, by utilizing the recess formed on the inner circumferential surface of the through hole 73 as the gap 75, the weight balance of the rotating body can be achieved without any change in appearance.

[0115] (3.2) The self-rotation structure of domestic sales

[0116] Next, regarding the rotation structure of the inner pin 4 of the gear device 1 in this basic structure, refer to... Figure 9 To explain in more detail. Figure 9 yes Figure 3 A magnified view of region Z1.

[0117] First, as mentioned above, the multiple inner pins 4 are components that connect the planetary gear 3 to the inner ring 61 of the bearing member 6. Specifically, one end of the inner pin 4 in the longitudinal direction (the end on the input side of the rotating shaft Ax1 in this basic structure) is inserted into the inner pin hole 32 of the planetary gear 3, and the other end of the inner pin 4 in the longitudinal direction (the end on the output side of the rotating shaft Ax1 in this basic structure) is inserted into the retaining hole 611 of the inner ring 61.

[0118] Here, the diameter of the inner pin 4 is slightly smaller than the diameter of the inner pin hole 32, thus ensuring a clearance between the inner pin 4 and the inner circumferential surface 321 of the inner pin hole 32. The inner pin 4 can move within the inner pin hole 32, that is, it can move relative to the center of the inner pin hole 32. On the other hand, the diameter of the retaining hole 611 is larger than the diameter of the inner pin 4, but smaller than the diameter of the inner pin hole 32. In this basic structure, the diameter of the retaining hole 611 is approximately the same as the diameter of the inner pin 4, but slightly larger. Therefore, the movement of the inner pin 4 within the retaining hole 611 is restricted; that is, relative movement of the inner pin 4 relative to the center of the retaining hole 611 is prohibited. Therefore, the inner pin 4 is held in the planetary gear 3 in a state where it can revolve within the inner pin hole 32, and in a state where it cannot revolve relative to the inner ring 61 within the retaining hole 611. Thus, the oscillation component of planetary gear 3, that is, the revolution component of planetary gear 3, is absorbed by the inner pin hole 32 and the inner pin 4. Through multiple inner pins 4, the rotation (rotation component) of planetary gear 3, other than the oscillation component (revolution component), is transmitted to the inner ring 61.

[0119] However, in this basic structure, the diameter of the inner pin 4 is slightly larger than that of the retaining hole 611. Therefore, while the inner pin 4 is prohibited from revolving within the retaining hole 611 when inserted, it can still rotate within the retaining hole 611. That is, although the inner pin 4 is inserted into the retaining hole 611, it is not pressed into it, and thus it can rotate within the retaining hole 611. In this way, in the gear device 1 of this basic structure, each of the multiple inner pins 4 is held by the inner ring 61 in a state where it can rotate, so that when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 itself can rotate.

[0120] In summary, in this basic structure, the inner pin 4 is maintained in a state where it can both revolve and rotate within the inner pin hole 32 relative to the planetary gear 3, and is maintained in a state where it can only rotate within the retaining hole 611 relative to the inner ring 61. That is, the multiple inner pins 4, in their respective unconstrained rotational state (able to rotate), can rotate (revolve) around the rotation axis Ax1, and can revolve within the multiple inner pin holes 32. Therefore, when the rotation (rotational component) of the planetary gear 3 is transmitted to the inner ring 61 using the multiple inner pins 4, the inner pin 4 can revolve and rotate within the inner pin hole 32, and simultaneously rotate within the retaining hole 611. Therefore, when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 is in a state where it can rotate, and thus rolls relative to the inner circumferential surface 321 of the inner pin hole 32. In other words, the inner pin 4 revolves within the inner pin hole 32 by rolling on the inner circumferential surface 321 of the inner pin hole 32, thus making it difficult to generate losses caused by frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4.

[0121] Thus, in this basic structure, since it is inherently difficult to generate losses due to frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, the inner roller can be omitted. Therefore, in this basic structure, each of the multiple inner pins 4 adopts a structure in which it directly contacts the inner circumferential surface 321 of the inner pin hole 32. That is, in this basic structure, the inner pin 4 without the inner roller is inserted into the inner pin hole 32, and the inner pin 4 directly contacts the inner circumferential surface 321 of the inner pin hole 32. As a result, the inner roller can be omitted, and the diameter of the inner pin hole 32 can be kept relatively small. Therefore, the planetary gear 3 can be miniaturized (especially the diameter can be reduced), and the gear assembly 1 as a whole can also be easily miniaturized. If the size of the planetary gear 3 is fixed, compared with the first related technology described above, for example, the number of inner pins 4 can be increased to make the rotational transmission smoother, or the inner pins 4 can be thickened to increase strength. In addition, the number of parts can be reduced to a corresponding amount corresponding to the inner roller, which also helps to reduce the cost of the gear assembly 1.

[0122] Furthermore, in the gear assembly 1 of this basic structure, each of the plurality of inner pins 4 is at least a portion disposed axially in the same position as the bearing member 6. That is, as shown... Figure 9As shown, in a direction parallel to the rotation axis Ax1, the inner pin 4 positions at least a portion of itself in the same location as the bearing member 6. In other words, at least a portion of the inner pin 4 is located between the two end faces of the bearing member 6 in a direction parallel to the rotation axis Ax1. Furthermore, each of the plurality of inner pins 4 positions at least a portion inside the outer ring 62 of the bearing member 6. In this basic structure, the output end of the inner pin 4 on the rotation axis Ax1 is positioned in the same location as the bearing member 6 in a direction parallel to the rotation axis Ax1. In summary, the output end of the inner pin 4 on the rotation axis Ax1 is inserted into the retaining hole 611 formed in the inner ring 61 of the bearing member 6, thus at least this end is positioned in the same location as the bearing member 6 in the axial direction.

[0123] In this way, at least a portion of each of the plurality of inner pins 4 is arranged in the same position as the bearing member 6 in the axial direction, thereby reducing the size of the gear assembly 1 in the direction parallel to the rotation axis Ax1. That is, compared with the structure in which the bearing member 6 and the inner pins 4 are arranged side by side (opposite) in the axial direction of the bearing member 6, the gear assembly 1 in this basic structure can reduce the size of the gear assembly 1 in the direction parallel to the rotation axis Ax1, and can contribute to further miniaturization (thinning) of the gear assembly 1.

[0124] Here, the opening surface of the output side of the rotating shaft Ax1 in the hole 611 is closed, for example, by an output shaft integrated with the inner ring 61. Thus, regarding the output side of the rotating shaft Ax1 via the inner pin 4 ( Figure 9 The movement of the right side is restricted by the output shaft integrated with the inner ring 61.

[0125] Furthermore, in this basic structure, the following structure is adopted to ensure smooth rotation of the inner pin 4 relative to the inner ring 61. That is, the rotation of the inner pin 4 is smoothed by placing lubricant (lubricating oil) between the inner circumferential surface of the retaining hole 611 formed in the inner ring 61 and the inner pin 4. In particular, in this basic structure, there is a lubricant retaining space 17 for lubricant injection between the inner ring 61 and the outer ring 62, so the smooth rotation of the inner pin 4 is achieved by utilizing the lubricant in the lubricant retaining space 17.

[0126] In this basic structure, such as Figure 9As shown, the inner ring 61 has: a plurality of retaining holes 611 into which a plurality of inner pins 4 are respectively inserted; and a plurality of connecting paths 64. The plurality of connecting paths 64 connect the lubricant retaining space 17 between the inner ring 61 and the outer ring 62 to the plurality of retaining holes 611. Specifically, a connecting path 64 is formed in the inner ring 61 extending radially from a portion of the inner circumferential surface of the retaining hole 611, i.e., the portion corresponding to the rolling element 63. The connecting path 64 is a hole that passes through the bottom surface of the recess (groove) accommodating the rolling element 63 in the opposing surface of the inner ring 61 opposite to the outer ring 62 and the inner circumferential surface of the retaining hole 611. In other words, the opening surface of the connecting path 64 on the side of the lubricant retaining space 17 is arranged in a position facing (opposite) to the rolling element 63 on the bearing member 6. The lubricant retaining space 17 and the retaining hole 611 are spatially connected via such a connecting path 64.

[0127] According to the above structure, since the lubricant holding space 17 is connected to the holding hole 611 by the connecting passage 64, the lubricant in the lubricant holding space 17 is supplied to the holding hole 611 through the connecting passage 64. That is, when the bearing member 6 moves and the rolling element 63 rotates, the rolling element 63 functions as a pump, which can deliver the lubricant in the lubricant holding space 17 to the holding hole 611 through the connecting passage 64. In particular, the opening surface of the connecting passage 64 on the lubricant holding space 17 side is in a position facing (opposite) to the rolling element 63 of the bearing member 6, so that the rolling element 63 functions efficiently as a pump when it rotates. As a result, the lubricant is between the inner circumferential surface of the holding hole 611 and the inner pin 4, which enables smooth rotation of the inner pin 4 relative to the inner ring 61.

[0128] (3.3) Support body

[0129] Next, regarding the structure of the support body 8 of the gear device 1 in this basic structure, refer to... Figure 10 To explain in more detail. Figure 10 yes Figure 3 The sectional view along line B1-B1. However, in Figure 10 In the text, for components other than support body 8, even in cross-sections, section lines are omitted. Furthermore, in... Figure 10 Only the internal gear 2 and the support body 8 are shown in the diagram; other components (such as the inner pin 4) are omitted. Furthermore, in... Figure 10 The inner circumferential surface 221 of the gear body 22 is omitted from the diagram.

[0130] First, as mentioned above, the support body 8 is a component that supports the plurality of inner pins 4. That is, the support body 8 distributes the load acting on the plurality of inner pins 4 when transmitting the rotation (rotation component) of the planetary gear 3 to the inner ring 61 by binding the plurality of inner pins 4. Specifically, it has a plurality of support holes 82 into which the plurality of inner pins 4 are inserted respectively. In this basic structure, as an example, the diameter of the support hole 82 is equal to the diameter of the retaining hole 611 formed in the inner ring 61. Therefore, the support body 8 supports the plurality of inner pins 4 in a state in which each of the plurality of inner pins 4 can rotate on its own axis. That is, each of the plurality of inner pins 4 is held in a state in which it can rotate relative to both the inner ring 61 of the bearing member 6 and the support body 8.

[0131] In this way, multiple inner pins 4 are positioned relative to the support body 8 in both the circumferential and radial directions. That is, the inner pins 4 are restricted from moving in all directions within a plane orthogonal to the rotation axis Ax1 by means of the support holes 82 inserted into the support body 8. Therefore, the inner pins 4 are positioned by the support body 8 not only in the circumferential direction but also in the radial direction.

[0132] Here, the support body 8 has an annular shape, at least its outer peripheral surface 81 being a perfect circle when viewed from above. Furthermore, the support body 8 is positionally constrained by contacting its outer peripheral surface 81 with a plurality of pins 23 in the internal gear 2. Since the plurality of pins 23 constitute the internal teeth 21 of the internal gear 2, in other words, the support body 8 is positionally constrained by contacting its outer peripheral surface 81 with the internal teeth 21. Here, the diameter of the outer peripheral surface 81 of the support body 8 is the same as the diameter of the virtual circle (tip circle) passing through the tip of the internal teeth 21 of the internal gear 2. Therefore, all of the plurality of pins 23 are in contact with the outer peripheral surface 81 of the support body 8. Thus, with the support body 8 positionally constrained by the plurality of pins 23, the center of the support body 8 is positionally constrained in a manner that overlaps with the center (rotation axis Ax1) of the internal gear 2. Therefore, the support body 8 is centered, and as a result, the plurality of internal pins 4 supported on the support body 8 are also centered using the plurality of pins 23.

[0133] Furthermore, the multiple inner pins 4 rotate (revolve) around the rotation axis Ax1, thereby transmitting the rotation (rotation component) of the planetary gear 3 to the inner ring 61. Therefore, the support body 8, which supports the multiple inner pins 4, rotates together with the multiple inner pins 4 and the inner ring 61 around the rotation axis Ax1. At this time, the support body 8 is centered by the multiple pins 23, so the support body 8 rotates smoothly with its center maintained on the rotation axis Ax1. Moreover, the support body 8 rotates with its outer circumferential surface 81 in contact with the multiple pins 23, so the multiple pins 23 rotate (rotate) along with the rotation of the support body 8. Thus, the support body 8 and the internal gear 2 together constitute a needle roller bearing (needle roller bearing) and rotate smoothly.

[0134] That is, the outer peripheral surface 81 of the support body 8 rotates relative to the gear body 22 together with the multiple inner pins 4 in a state of tangency to the multiple pins 23. Therefore, if the gear body 22 of the internal gear 2 is regarded as the "outer ring" and the support body 8 as the "inner ring", then the multiple pins 23 between the two function as "rolling elements (rollers)". In this way, the support body 8 and the internal gear 2 (gear body 22 and multiple pins 23) together constitute a needle roller bearing and can rotate smoothly.

[0135] Furthermore, since the support body 8 has multiple pins 23 sandwiched between it and the gear body 22, the support body 8 also functions as a "limiting member" to inhibit the movement of the pins 23 in the direction of separation from the inner circumferential surface 221 of the gear body 22. That is, the multiple pins 23 are sandwiched between the outer circumferential surface 81 of the support body 8 and the inner circumferential surface 221 of the gear body 22, thereby inhibiting the multiple pins 23 from floating off the inner circumferential surface 221 of the gear body 22. In summary, in this basic structure, each of the multiple pins 23 is restricted from moving in the direction of separation from the gear body 22 by contacting the outer circumferential surface 81 of the support body 8.

[0136] However, in this basic structure, such as Figure 9 As shown, the support 8 is located on the opposite side of the bearing member 6 from the inner ring 61, separated from the planetary gear 3. That is, the support 8, the planetary gear 3, and the inner ring 61 are arranged side by side along a direction parallel to the rotation axis Ax1. In this basic structure, as an example, the support 8 is located on the input side of the rotation axis Ax1 when viewed from the planetary gear 3, and the inner ring 61 is located on the output side of the rotation axis Ax1 when viewed from the planetary gear 3. Furthermore, the support 8 and the inner ring 61 together support the two ends of the inner pin 4 along its length (in the direction parallel to the rotation axis Ax1), and the central portion of the inner pin 4 along its length is inserted through the inner pin hole 32 of the planetary gear 3. In summary, the gear device 1 of this basic structure includes a bearing member 6, which has an outer ring 62 and an inner ring 61 disposed inside the outer ring 62, and the inner ring 61 is supported so as to be able to rotate relative to the outer ring 62. Furthermore, the gear body 22 is fixed to the outer ring 62. Here, the planetary gear 3 is located axially between the support body 8 and the inner ring 61.

[0137] According to this structure, the support body 8 and the inner ring 61 support the two ends of the inner pin 4 along its length, thus making it difficult for the inner pin 4 to tilt. In particular, it easily accepts the bending force (bending moment load) acting on the multiple inner pins 4 relative to the rotating shaft Ax1. Furthermore, in this basic structure, the support body 8 is sandwiched between the planetary gear 3 and the housing 10 in a direction parallel to the rotating shaft Ax1. Therefore, the support body 8 is directed towards the input side of the rotating shaft Ax1 (… Figure 9The movement of the left side is restricted by the housing 10. Regarding the support hole 82 penetrating the support body 8 and the inner pin 4 protruding from the support body 8 towards the input side of the rotating shaft Ax1, the movement of the inner pin 4 towards the input side of the rotating shaft Ax1 is restricted. Figure 9 The movement of the left side is also restricted by the housing 10.

[0138] In this basic structure, the support body 8 and the inner ring 61 also contact the two ends of a plurality of pins 23. That is, as Figure 9 As shown, the support body 8 contacts one end of the pin 23 along its length (parallel to the rotation axis Ax1) (the input end of the rotation axis Ax1). The inner ring 61 contacts the other end of the pin 23 along its length (parallel to the rotation axis Ax1) (the output end of the rotation axis Ax1). With this structure, the support body 8 and the inner ring 61 are centered at both ends along the length of the pin 23, thus preventing tilting of the inner pin 4. In particular, it easily withstands bending forces (bending moment loads) acting on the rotation axis Ax1 from the multiple inner pins 4.

[0139] Furthermore, the multiple pins 23 have a length exceeding the thickness of the support body 8. In other words, the support body 8 is contained within the tooth direction of the internal teeth 21 in the direction parallel to the rotation axis Ax1. As a result, the outer peripheral surface 81 of the support body 8 contacts the multiple pins 23 along the entire length of the tooth direction of the internal teeth 21 (the direction parallel to the rotation axis Ax1). Therefore, it is difficult to produce an undesirable condition such as "unilateral wear" where the outer peripheral surface 81 of the support body 8 is partially worn.

[0140] Furthermore, in this basic structure, the outer peripheral surface 81 of the support 8 has a smaller surface roughness than the surface of the support 8 adjacent to the outer peripheral surface 81. That is, the surface roughness of the outer peripheral surface 81 is smaller than that of the two end faces of the support 8 in the axial (thickness direction). The term "surface roughness" as used in this embodiment refers to the degree of roughness of an object's surface; the smaller the value, the less unevenness (roughness) the surface, and the smoother it is. In this basic structure, as an example, the surface roughness is set to the arithmetic mean roughness (Ra). For example, through processes such as grinding, the outer peripheral surface 81 has a smaller surface roughness than the surfaces of the support 8 other than the outer peripheral surface 81. In this structure, the rotation of the support 8 becomes smoother.

[0141] Furthermore, in this basic structure, the hardness of the outer peripheral surface 81 of the support body 8 is lower than that of the peripheral surfaces of the plurality of pins 23 and higher than that of the inner peripheral surface 221 of the gear body 22. The term "hardness" as used in this embodiment refers to the degree of hardness of an object; the hardness of a metal is, for example, expressed by the size of the indentation formed when a steel ball is pressed under a certain pressure. Specifically, examples of metal hardness include Rockwell hardness (HRC), Brinell hardness (HB), Vickers hardness (HV), or Shore hardness (Hs). Methods for increasing the hardness (hardening) of metal parts include, for example, alloying or heat treatment. In this basic structure, as an example, the hardness of the outer peripheral surface 81 of the support body 8 is increased through treatments such as carburizing and quenching. In this structure, even due to the rotation of the support body 8, wear particles are unlikely to be generated, and the smooth rotation of the support body 8 can be easily maintained for a long period.

[0142] (4) Applicable examples

[0143] Next, an applicable example of the gear device 1 and actuator 100 of this basic structure will be described.

[0144] The gear assembly 1 and actuator 100 of this basic structure are suitable for robots such as horizontal articulated robots, i.e., robots of the so-called Selective Compliance Assembly Robot Arm (SCARA) type.

[0145] Furthermore, the application examples of the gear device 1 and actuator 100 of this basic structure are not limited to horizontal articulated robots as described above. For example, they can also be industrial robots or robots other than horizontal articulated robots. Among industrial robots other than horizontal articulated robots, examples include vertical articulated robots or parallel linkage robots. Among robots other than industrial robots, examples include home robots, nursing robots, or medical robots.

[0146] (Implementation Method 1)

[0147] <Summary>

[0148] The internal meshing planetary gear device 1A (hereinafter also simply referred to as "gear device 1A") of this embodiment is as follows: Figures 11-14 As shown, the main difference is in the structure around the bearing component 6A compared to the gear assembly 1 in the basic structure. Hereinafter, structures identical to the basic structure will be labeled with the same reference numerals and descriptions will be omitted as appropriate.

[0149] Figure 11 This is a schematic cross-sectional view of gear assembly 1A. Figure 12 It is the output side of the gear device 1A from the rotating shaft Ax1 ( Figure 11 Side view observed from the right side. Figure 11 Equivalent to Figure 12 Sectional view along line C1-C1. Figure 13 yes Figure 11 Sectional view along line A1-A1, Figure 14 yes Figure 11 The sectional view along line B1-B1 and its enlarged partial view. Among them, in Figure 13 and Figure 14 In the middle, regarding the components other than the eccentric shaft 7, although they are cross-sections, the cross-section lines are omitted.

[0150] In this embodiment, the bearing member 6A has an outer ring 62A, an inner ring 61A disposed inside the outer ring 62A, and a plurality of rolling elements 63 disposed between the outer ring 62A and the inner ring 61A. Furthermore, the inner ring 61A is supported so that it can rotate relative to the outer ring 62A about a rotation axis Ax1. This is the same as in the basic structure.

[0151] Regarding the gear device 1A of this embodiment, as the first major difference from the basic structure, the inner ring 61A of the bearing member 6A is not composed of a single component but comprises two components: a first inner ring 601 and a second inner ring 602. That is, as... Figure 11 As shown, in gear assembly 1A, the inner ring 61A includes opposing and opposite surfaces 601A and 602A (see reference) in a direction parallel to the rotation axis Ax1. Figure 15 The first inner circle 601 and the second inner circle 602 are in contact with each other.

[0152] Furthermore, as a second major difference between the gear device 1A of this embodiment and the basic structure, the outer ring 62A of the bearing member 6A is not separately formed from the gear body 22 of the internal gear 2, but is seamlessly integrally formed with the gear body 22. That is, as... Figure 11 As shown, in the gear assembly 1A, the outer ring 62A and the gear body 22 are seamlessly and continuously arranged in a direction parallel to the rotation axis Ax1 (the tooth direction of the internal teeth 21).

[0153] In summary, regarding the gear device 1A of this embodiment, the main difference from the basic structure is the new use of drilling for the inner ring 61A and the outer ring 62A of the bearing member 6A. The drilling for the inner ring 61A includes having a first inner ring 601 and a second inner ring 602, and the drilling for the outer ring 62A includes seamlessly and continuously connecting the outer ring 62A to the gear body 22.

[0154] Other differences

[0155] In the gear device 1A of this embodiment, apart from the main differences mentioned above (the drilling of the inner ring 61A and the drilling of the outer ring 62A), there are several differences relative to the basic structure as described below.

[0156] As another first difference, the gear device 1A of this embodiment is used in a manner that allows the rotation of the planetary gear 3, corresponding to its rotational component, to be extracted as the rotation of the output shaft, etc., which is integrated with the outer ring 62A of the bearing member 6A. That is, in the basic structure, the relative rotation between the planetary gear 3 and the internal gear 2 is extracted as the rotational component of the planetary gear 3 from the inner ring 61 connected to the planetary gear 3 by a plurality of inner pins 4. In contrast, in this embodiment, the relative rotation between the planetary gear 3 and the internal gear 2 is extracted from the outer ring 62A, which is integrated with the gear body 22 of the internal gear 2. In this embodiment, as an example, the gear device 1A is used in a state in which the inner ring 61A of the plurality of inner pins 4 is fixed to the fixing member (such as the hub member 104 described later) and the outer ring 62A is fixed to the housing 10, which serves as the rotating member. That is, since the planetary gear 3 is connected to the fixing member by a plurality of inner pins 4 and the gear body 22 is fixed to the rotating member, the relative rotation between the planetary gear 3 and the internal gear 2 is extracted from the internal gear 2 (gear body 22). In other words, in this embodiment, the gear device 1A is configured to output the rotational force of the gear body 22 when the plurality of inner pins 4 rotate relative to the gear body 22.

[0157] Furthermore, taking the gear device 1A, which extracts the rotational force of the gear body 22 as its output, as an example, it is used in the wheel device W1 (see reference). Figure 17 In this case, the rotating member (housing 10) serves as the wheel body 102 (see reference). Figure 17 The gear mechanism 1A functions such that the wheel body 102 can rotate along with the relative rotation of the internal gear 2 and the planetary gear 3. Thus, in this embodiment, by using the gear mechanism 1A for the wheel assembly W1, the wheel body 102 can be driven to roll on the travel surface by utilizing the rotational output of the multiple internal pins 4 relative to the gear body 22. In summary, when the gear mechanism 1A is used as the wheel assembly W1, it applies a rotational force as input to the eccentric shaft 7, thereby extracting a rotational force as output from the rotating member that serves as the wheel body 102. That is, the gear mechanism 1A operates with the rotation of the eccentric shaft 7 as input rotation and the rotation of the rotating member to which the gear body 22 is fixed as output rotation. Therefore, in the gear mechanism 1A, it is possible to obtain an output rotation that is reduced at a relatively high reduction ratio relative to the input rotation as the rotation of the wheel body 102.

[0158] As a second difference, the gear device 1A of this embodiment includes a plurality of planetary gears 3. Specifically, the gear device 1A includes two planetary gears 3: a first planetary gear 301 and a second planetary gear 302. The two planetary gears 3 are configured to face each other in a direction parallel to the rotation axis Ax1. That is, the planetary gears 3 include a first planetary gear 301 and a second planetary gear 302 facing each other in a direction parallel to the rotation axis Ax1.

[0159] The two planetary gears 3 (first planetary gear 301 and second planetary gear 302) are arranged about the rotation axis Ax1 with a phase difference of 180 degrees. Figure 11 In the example, the first planetary gear 301 and the second planetary gear 302 located on the input side of the rotating shaft Ax1 ( Figure 11 The center C1 of the first planetary gear 301 (on the left side) is in a state that is offset (biased) from the top relative to the rotation axis Ax1. On the other hand, the output side of the rotation axis Ax1 ( Figure 11 The center C2 of the second planetary gear 302 (on the right side) is offset (biased) downward relative to the rotation axis Ax1. Thus, by arranging the multiple planetary gears 3 evenly in the circumferential direction centered on the rotation axis Ax1, weight balance among the multiple planetary gears 3 can be achieved. In the gear device 1A of this embodiment, since weight balance is achieved among the multiple planetary gears 3 in this way, the clearance 75 of the eccentric shaft 7 (see reference 1A) is omitted. Figure 3 ).

[0160] More specifically, the eccentric shaft 7 has two eccentric portions 72 relative to a central portion 71. The centers (central axes) of these two eccentric portions 72 coincide with centers C1 and C2, respectively, which are offset from the rotation axis Ax1. Furthermore, the first planetary gear 301 and the second planetary gear 302 have identical shapes. An eccentric bearing 5, centered on center C1 and mounted on the eccentric portion 72, is housed in the opening 33 of the first planetary gear 301. Similarly, an eccentric bearing 5, centered on center C2 and mounted on the eccentric portion 72, is housed in the opening 33 of the second planetary gear 302. Here, the distance ΔL1 between the rotation axis Ax1 and the center C1 is the eccentricity of the first planetary gear 301 relative to the rotation axis Ax1, and the distance ΔL2 between the rotation axis Ax1 and the center C2 is the eccentricity of the second planetary gear 302 relative to the rotation axis Ax1. In this embodiment, although the eccentricity ΔL1 and eccentricity ΔL2 are oriented in opposite directions when viewed from the rotation axis Ax1, their absolute values ​​are the same. According to the above structure, the shaft center 71 rotates (rotates) around the rotation axis Ax1, thereby causing the first planetary gear 301 and the second planetary gear 302 to rotate (eccentrically move) around the rotation axis Ax1 with a phase difference of 180 degrees.

[0161] As a third difference, in this embodiment, such as Figure 13 and Figure 14 As shown, the eccentric bearing 5 is constructed of a roller bearing instead of the deep groove ball bearing described in the basic structure. That is, in the gear device 1A of this embodiment, the eccentric bearing 5 uses cylindrical rollers as rolling elements 53. Furthermore, in this embodiment, the inner ring 51 of the eccentric bearing is omitted (see reference). Figure 3 ) and eccentric outer ring 52 (refer to Figure 3 Therefore, the inner circumferential surface of the planetary gear 3 (opening 33) replaces the rolling surface of the multiple rolling elements 53 instead of the outer ring 52 of the eccentric portion 72, and the outer circumferential surface of the eccentric portion 72 replaces the rolling surface of the multiple rolling elements 53 instead of the inner ring 51 of the eccentric portion 72. In this embodiment, the eccentric bearing 5 has a cage (retainer) 54, and the multiple rolling elements 53 are each held by the cage 54 in a rotatable state. The cage 54 holds the multiple rolling elements 53 at equal intervals in the circumferential direction of the eccentric portion 72. Furthermore, the cage 54 is not fixed relative to the planetary gear 3 and the eccentric shaft 7, and can rotate relative to the planetary gear 3 and the eccentric shaft 7, respectively. Thus, with the rotation of the cage 54, the multiple rolling elements 53 held by the cage 54 move in the circumferential direction of the eccentric portion 72.

[0162] As a fourth difference, in this embodiment, the housing 10 is seamlessly integrated with the gear body 22 of the internal gear 2 and the outer ring 62A of the bearing member 6A. That is, in the basic structure, the gear body 22 of the internal gear 2 is used in a state where it is fixed to the housing 10 together with the outer ring 62 of the bearing member 6. In contrast, in this embodiment, through the refinement of the outer ring 62A, the outer ring 62A, which is seamlessly and continuously provided with the gear body 22 in a direction parallel to the rotation axis Ax1, is also seamlessly and continuously provided with the housing 10, which is a rotating member.

[0163] More specifically, the housing 10 is cylindrical and forms the outline of the gear device 1A. In this embodiment, since the housing 10, as a rotating member, functions as, for example, the wheel body 102, the central axis of the cylindrical housing 10 is configured to coincide with the rotation axis Ax1. That is, at least the outer peripheral surface of the housing 10, when viewed from above (from the direction of the rotation axis Ax1), is a perfect circle centered on the rotation axis Ax1. Figure 11 As shown, the housing 10 has a main body 18 and a cover 19. The main body 18 is a cylindrical component with openings at both ends in the direction of the rotation axis Ax1. The cover 19 is the input side of the rotation axis Ax1 installed in the main body 18. Figure 11The left end face of the gear body 22 and the outer ring 62A of the bearing member 6A are closed by a disc-shaped component that encloses the opening face of the input side of the rotating shaft Ax1 in the main body 18. Furthermore, in this embodiment, the gear body 22 of the internal gear 2 and the outer ring 62A of the bearing member 6A are seamlessly integrated into the main body 18 in the housing 10. Thus, the gear body 22 and the outer ring 62A are treated as a single component (main body 18). Therefore, the inner circumferential surface of the main body 18 includes the inner circumferential surface 221 of the gear body 22 (see reference 18). Figure 14 ) and the inner circumferential surface 620 of the outer ring 62A (refer to Figure 13 ).

[0164] In addition to the points mentioned above, for example, the number of teeth, reduction ratio, number of internal pin holes 32 and internal pins 4, and the specific shape and size of each part of the internal gear 2 and planetary gear 3 are also appropriately different from those in the basic structure. For example, there are 18 internal pin holes 32 and internal pins 4 in the basic structure, while in this embodiment, as an example, there are 12 of each.

[0165] <In-depth study of the inner circle>

[0166] Next, refer to Figures 11-16 The grinding of the inner ring 61A of the bearing member 6A in the gear device 1A of this embodiment is described in detail.

[0167] In this embodiment, as described above, the inner ring 61A of the bearing member 6A is configured to include two components: a first inner ring 601 and a second inner ring 602, which are opposite each other in a direction parallel to the rotation axis Ax1. The first inner ring 601 and the second inner ring 602 are combined in a state where their opposing surfaces 601A and 602A are in contact with each other. In other words, the inner ring 61A is divided into the two components, the first inner ring 601 and the second inner ring 602, which are arranged side by side in a direction parallel to the rotation axis Ax1.

[0168] Both the first inner ring 601 and the second inner ring 602 are annular components. Both the first inner ring 601 and the second inner ring 602 are circular rings that appear perfectly round when viewed from above. In the first inner ring 601 and the second inner ring 602, the outer diameter... (Refer to Figure 15 The inner diameters are also approximately the same. In this embodiment, as an example, the second inner ring 602 is larger than the first inner ring 601 in the direction parallel to the rotation axis Ax1, but this dimensional relationship is not limited to.

[0169] The first inner ring 601 and the second inner ring 602 are both one size smaller than the outer ring 62A and are positioned inside the outer ring 62A. Here, the inner diameter of the outer ring 62A... (Refer to Figure 15 The outer diameters of the first inner ring 601 and the second inner ring 602 are compared. The outer diameter is large, thus creating a gap between the inner circumferential surface 620 of the outer ring 62A and the outer circumferential surfaces of the first inner ring 601 and the second inner ring 602. Furthermore, although details are described later, the outer diameters of the first inner ring 601 and the second inner ring 602... The multiple pin retaining grooves 223 of the inner circumferential surface 221 of the gear body 22 (see reference) Figure 14 The virtual circle VC1 at the bottom of ) Figure 14 (Reference) diameter (Refer to Figure 15 Smaller.

[0170] Here, the first inner ring 601 and the second inner ring 602 are configured such that, in a direction parallel to the rotation axis Ax1, the first inner ring 601 is on the side of the planetary gear 3, and the second inner ring 602 is on the opposite side to the planetary gear 3. In other words, the first inner ring 601 and the second inner ring 602 are configured such that the first inner ring 601 is on the input side of the rotation axis Ax1. Figure 11 (Left side), the second inner ring 602 is the output side of the rotating shaft Ax1 ( Figure 11 (Right side). Therefore, the opposing surface 601A in the first inner ring 601, which is opposite to the second inner ring 602, is located on the output side of the first inner ring 601 facing the rotation axis Ax1. Figure 11 The surface on the right side is formed. Conversely, the opposing surface 602A in the second inner ring 602, which is opposite to the first inner ring 601, is formed by the input side of the second inner ring 602 facing the rotation axis Ax1. Figure 11 The surface of the left side is formed. The first inner ring 601 and the second inner ring 602 are combined with each other in such a way that their opposite surfaces 601A and 602A are in contact with each other to form the inner ring 61A.

[0171] When the first inner ring 601 and the second inner ring 602 are combined as described above, such as Figure 12 As shown, the inner rings 61A and 602 are joined using multiple locating pins 65 and multiple bolts 66. The locating pins 65 are pressed from the first inner ring 601 towards the second inner ring 602 into multiple holes that penetrate the inner ring 61A in a direction parallel to the rotation axis Ax1. Furthermore, the bolts 66 pass through the second inner ring 602 and are tightened onto the first inner ring 601. Therefore, the first inner ring 601 and the second inner ring 602 are joined using multiple bolts 66 while their relative positions in a plane orthogonal to the rotation axis Ax1 are positioned by the locating pins 65.

[0172] Here, in bearing component 6A, as Figure 15As shown, a plurality of rolling elements 63 are located on the dividing surface between the first inner ring 601 and the second inner ring 602 in the inner ring 61A. In this embodiment, the opposing surface 601A of the first inner ring 601 opposite to the second inner ring 602 is the dividing surface between the first inner ring 601 and the second inner ring 602, therefore the plurality of rolling elements 63 are located on a plane including the opposing surface 601A of the first inner ring 601 opposite to the second inner ring 602. In this embodiment, the bearing member 6A is a crossed roller bearing that bears radial loads, thrust loads (in the direction along the rotation axis Ax1), and bending forces (bending moment loads) relative to the rotation axis Ax1. Therefore, the plurality of rolling elements 63 of the bearing member 6 are each composed of cylindrical rollers inclined at 45 degrees relative to a plane orthogonal to the rotation axis Ax1. Such a plurality of rolling elements 63 are located on the same plane of the opposing surface 601A of the first inner ring 601 opposite to the second inner ring 602.

[0173] In this embodiment, the centers of the plurality of rolling elements 63 in the direction parallel to the rotation axis Ax1 are located on the same plane of the opposing surface 601A of the first inner ring 601, which is opposite to the second inner ring 602. In other words, the inner ring 61A is divided into the first inner ring 601 and the second inner ring 602, with the plane containing the centers of the plurality of rolling elements 63 in the direction parallel to the rotation axis Ax1 as the dividing plane. With this structure, during the assembly of the bearing component 6A, the plurality of rolling elements 63 disposed on the outer ring 62A are sandwiched between the first inner ring 601 and the second inner ring 602 from both sides in the direction parallel to the rotation axis Ax1, thereby making the assembly of the bearing component 6A relatively simple.

[0174] In this embodiment, oil seal 15 fills the gap between the second inner ring 602 and the eccentric shaft 7 (shaft center 71). Similarly, oil seal 16 fills the gap between the second inner ring 602 and the outer ring 62. The space sealed by the plurality of oil seals 14, 15, and 16 constitutes the lubricant retention space 17 in the same manner as the basic structure (see reference). Figure 11 ).

[0175] In this way, the inner ring 61A is divided into two parts: a first inner ring 601 and a second inner ring 602, thereby creating a gap, even if small, between the first inner ring 601 and the second inner ring 602. By creating such a gap, for example, lubricant can easily circulate within the lubricant holding space 17. In particular, if the gap between the first inner ring 601 and the second inner ring 602 is small, the lubricant within the lubricant holding space 17 is expected to expand through the gap due to, for example, capillary action. Therefore, compared to the case where the inner ring 61A is not divided into the first inner ring 601 and the second inner ring 602, even during long-term use of the gear mechanism 1A, the lubricant can easily spread throughout the entire lubricant holding space 17, making it less likely for adverse conditions such as a decrease in transmission efficiency in the gear mechanism 1A to occur.

[0176] Furthermore, by dividing the inner ring 61A into two parts, the first inner ring 601 and the second inner ring 602, the bearing component 6A can be easily assembled without significantly complicating the machining of the inner ring 61A. Moreover, by keeping the machining of the inner ring 61A simple, the size of the inner ring 61 can be kept relatively small, thus enabling a more compact bearing component 6A as a crossed roller bearing.

[0177] However, in this embodiment, similar to the basic structure, multiple inner pins 4 connect the planetary gear 3 to the inner ring 61A of the bearing member 6A. Specifically, one end of the inner pin 4 in the longitudinal direction (the end on the input side of the rotating shaft Ax1) is inserted into the inner pin hole 32 of the planetary gear 3 (the first planetary gear 301 and the second planetary gear 302), and the other end of the inner pin 4 in the longitudinal direction (the end on the output side of the rotating shaft Ax1) is inserted into the retaining hole 611 of the inner ring 61A.

[0178] Furthermore, since the diameter of the inner pin 4 is slightly larger than that of the retaining hole 611, the inner pin 4, while prohibited from revolving within the retaining hole 611 when inserted into the bearing member 6A, can still rotate within the retaining hole 611. That is, although the inner pin 4 is inserted into the retaining hole 611, it is not pressed into it, and therefore can rotate within the retaining hole 611. Thus, in the gear device 1A of this embodiment, each of the multiple inner pins 4 is held in the inner ring 61A in a state where it can rotate, so when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 itself can also rotate.

[0179] In this embodiment, unlike the basic structure, each of the multiple retaining holes 611 is configured not to penetrate the entire inner ring 61A, but only to penetrate the first inner ring 601 within the inner ring 61A. That is, the first inner ring 601 has multiple retaining holes 611 in a direction parallel to the rotation axis Ax1, through which the multiple inner pins 4 respectively pass. Furthermore, the inner pins 4 are retained in the inner ring 61A by inserting their other end in the longitudinal direction (the end on the output side of the rotation axis Ax1) into the retaining hole 611.

[0180] In this embodiment, since the inner pin 4 is not inserted into the second inner ring 602, the retaining hole 611 is not provided in the second inner ring 602. Therefore, the end faces of the plurality of inner pins 4 are in contact with the opposing surface 602A of the second inner ring 602 opposite to the first inner ring 601. That is, the end face of the inner pin 4 in the longitudinal direction opposite to the planetary gear 3 (output side of the rotating shaft Ax1) is in contact with the surface (opposing surface 602A) of the second inner ring 602. The end face of the inner pin 4 in the longitudinal direction can either lightly contact or separate from the opposing surface 602A of the second inner ring 602 to a degree that does not hinder the rotation of the inner pin 4. Therefore, the movement of the inner pin 4 toward the output side of the rotating shaft Ax1 is restricted by the second inner ring 602, and leakage of lubricant in the lubricant retaining space 17 through the retaining hole 611 can be suppressed.

[0181] Furthermore, since the diameter of the inner pin 4 is slightly larger than that of the retaining hole 611, a gap is formed between the inner circumferential surface of each of the plurality of retaining holes 611 of the first inner ring 601 and the outer circumferential surface of each of the plurality of inner pins 4. That is, the retaining hole 611 is a hole for the inner pin 4 to be fitted, and the inner pin 4 is inserted into the retaining hole 611 with sufficient space (gap) between it and the inner circumferential surface of the retaining hole 611. However, the inner pin 4 only needs to be able to rotate within the retaining hole 611, so the gap between the inner circumferential surface of the retaining hole 611 and the inner pin 4 is smaller than the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4. In addition, it is not necessary to ensure a gap as a void between the inner circumferential surface of the retaining hole 611 and the inner pin 4; for example, a fluid such as a liquid can be filled into the gap. Specifically, lubricant is filled into the gap between the inner circumferential surface of the retaining hole 611 and the inner pin 4. Therefore, the rotation of the inner pin 4 within the retaining hole 611 becomes smooth due to the lubricant.

[0182] In addition, such as Figure 16 As shown, the gear device 1A of this embodiment also includes a lubricant circulation path RL1. Figure 16In the diagram, the flow of lubricant through circulation path RL1 is schematically represented by dashed arrows. Circulation path RL1 is a path (circulation path) through which lubricant circulates, at least through the gap between the first inner ring 601 and the second inner ring 602, the spaces accommodating the rolling elements 63, and the retaining holes 611 of the plurality of retaining holes 611. That is, circulation path RL1 includes the gap between the first inner ring 601 and the second inner ring 602, the spaces accommodating the rolling elements 63, the retaining holes 611, and as shown... Figure 16 As shown, it is formed in a ring shape. Thus, lubricant injected, for example, into the space housing the rolling element 63, can easily recirculate back into the space housing the rolling element 63 along the circulation path RL1, passing through the gap between the first inner ring 601 and the second inner ring 602, and the gap between the inner circumferential surface of the retaining hole 611 and the inner pin 4. However, the direction in which the lubricant moves through the circulation path RL1 is not limited to... Figure 16 The direction indicated by the middle arrow can also be the opposite direction.

[0183] In addition, regarding the surface hardness of each component, the gear device 1A of this embodiment satisfies the following conditions.

[0184] That is, each of the plurality of inner pins 4 and the first inner ring 601 has the same level of surface hardness. Specifically, the difference between the surface hardness of each of the plurality of inner pins 4 and the surface hardness of the first inner ring 601 is HRC3 or less. That is, the surface hardness of the inner pin 4 is set in the range of ±3 based on the surface hardness of the first inner ring 601 using Rockwell hardness (HRC). Here, the difference between the surface hardness of the inner pin 4 and the surface hardness of the first inner ring 601 is preferably HRC2 or less, more preferably HRC1 or less. The "surface hardness of the first inner ring 601" referred to here refers to the hardness of at least the inner circumferential surface of the retaining hole 611 in the first inner ring 601. Since the first inner ring 601 holds the inner pin 4 in a self-rotating state within the retaining hole 611, as in this embodiment, by making the surface hardness of the inner pin 4 and the first inner ring 601 the same level (a difference of HRC3 or less), it is expected to suppress the wear of the inner pin 4 and the first inner ring 601. As a result, even with the rotation of the inner pin 4 within the retaining hole 611, it is difficult to generate wear powder, etc., and it is easy to maintain the smooth rotation of the inner pin 4 for a long time.

[0185] Furthermore, the surface hardness of each of the plurality of inner pins 4 is approximately HRC60. More precisely, the surface hardness of each of the plurality of inner pins 4 is within the range of HRC60±3. In this embodiment, since the surface hardness of the inner pins 4 and the first inner ring 601 is the same (a difference of less than HRC3), the surface hardness of the first inner ring 601 is within the range of HRC60±6. Here, the surface hardness of the inner pins 4 is preferably within the range of HRC60±2, and more preferably within the range of HRC60±1. As a result, even due to the rotation of the inner pins 4 within the retaining hole 611, it is difficult to generate wear particles, etc., and it is easy to maintain the smooth rotation of the inner pins 4 for a long time.

[0186] Furthermore, in this embodiment, the second inner ring 602 also adopts the same level of surface hardness as the first inner ring 601 (and the inner pin 4). Specifically, the difference between the surface hardness of the second inner ring 602 and the surface hardness of the first inner ring 601 is HRC3 or less. Methods for increasing the hardness (hardening) of metal parts include, for example, alloying or heat treatment.

[0187] <Study of the outer circle>

[0188] Next, refer to Figures 11-16 The grinding of the outer ring 62A of the bearing member 6A in the gear device 1A of this embodiment is described in detail.

[0189] In this embodiment, as described above, the outer ring 62A of the bearing member 6A is seamlessly and continuously provided with the gear body 22 in a direction parallel to the rotation axis Ax1 (the tooth direction of the internal teeth 21). The term "seamless" in this embodiment refers to a structure in which multiple components (parts) are connected without joints, meaning that these multiple components (parts) cannot be separated without damage. That is, in this embodiment, instead of combining the outer ring 62A, which is prepared as a separate component, with the gear body 22 using, for example, fasteners (bolts) or adhesives, the outer ring 62A and the gear body 22 are integrated in a seamless and continuous manner.

[0190] Specifically, for example, the outer ring 62A and the gear body 22 are integrally formed by machining a substrate made of a metal block, resulting in a seamless and continuous outer ring 62A and gear body 22. Alternatively, in the case of casting, the outer ring 62A and gear body 22 are integrally formed by flowing a substrate made of molten metal into a forming mold, resulting in a seamless and continuous outer ring 62A and gear body 22. Thus, in the gear device 1A of this embodiment, the outer ring 62A and gear body 22 are integrally formed, for example, by machining a substrate, thereby achieving a seamless and continuous outer ring 62A with the gear body 22 in a direction parallel to the rotation axis Ax1. In other words, the manufacturing method of the gear device 1A includes the step of integrally forming the outer ring 62A and gear body 22 by machining a substrate.

[0191] Thus, in the gear device 1A of this embodiment, by seamlessly and continuously arranging the outer ring 62A and the gear body 22 in a direction parallel to the rotation axis Ax1, it becomes easier to improve the centering accuracy of the internal gear 2 and the bearing member 6A. That is, the center of the gear body 22 of the internal gear 2 and the center of the outer ring 62A of the bearing member 6A can be easily maintained on the rotation axis Ax1 with high precision. As a result, the gear device 1A has the advantages of being less prone to vibrations caused by poor centering and less prone to adverse conditions such as a decrease in transmission efficiency.

[0192] Both the gear body 22 and the outer ring 62A have an annular shape that appears perfectly round when viewed from above. In this embodiment, in particular, the gear body 22 and the outer ring 62A are seamlessly integrated with the main body 18 of the housing 10. In other words, a portion of the main body 18 of the housing 10 functions as the gear body 22 and the outer ring 62A. Therefore, as Figure 15 As shown, the gear body 22 has the same outer diameter as the outer ring 62A. However, the gear body 22 differs from the outer ring 62A in terms of inner diameter.

[0193] Specifically, such as Figure 14 As shown, multiple grooves are formed on the inner circumferential surface 221 of the gear body 22, covering the entire circumferential area. These multiple grooves are multiple pin retaining grooves 223 that serve as retaining structures for multiple pins 23. In other words, the retaining structure for multiple pins 23 includes multiple pin retaining grooves 223 formed on the inner circumferential surface 221 of the gear body 22. All of the multiple pin retaining grooves 223 are of the same shape and are arranged at equal intervals. The multiple pin retaining grooves 223 are all formed parallel to the rotation axis Ax1 and cover the entire width of the gear body 22. However, in this embodiment, as described above, the gear body 22 is part of the main body portion 18, therefore the multiple pin retaining grooves 223 are only formed in the portion of the main body portion 18 corresponding to the gear body 22 (see reference). Figure 11Multiple pins 23 are fitted into multiple pin retaining grooves 223 and assembled into the gear body 22 (body part 18). Each of the multiple pins 23 is held in the pin retaining groove 223 in a state where it can rotate, and its movement in the circumferential direction of the gear body 22 is restricted by the pin retaining groove 223.

[0194] By forming multiple pin retaining grooves 223, the inner diameter of the gear body 22 is maximized at the bottom of the pin retaining grooves 223 and minimized outside the pin retaining grooves 223. In this embodiment, the diameter of the virtual circle VC1 passing through the bottom of the multiple pin retaining grooves 223 is... That is, the maximum value of the inner diameter of the gear body 22 is defined as the inner diameter of the gear body 22. Furthermore, as... Figure 15 As shown, the inner diameter of the gear body 22 The inner diameter of the outer ring 62A of the bearing component 6A They are different. In short, the inner diameter of the outer ring 62A is different. The diameter of the virtual circle VC1 at the bottom of the plurality of pin retaining grooves 223 that hold the plurality of pins 23 in the inner circumferential surface 221 of the gear body 22 is equal to the diameter of the virtual circle VC1. They are different. Therefore, even if the gear body 22 and the outer ring 62A are seamlessly continuous, the function of the gear body 22 and the outer ring 62A can be easily and clearly distinguished based on the difference in their inner diameters.

[0195] Furthermore, in this embodiment, such as Figure 15 As shown, the inner diameter of outer ring 62A The diameter of the virtual circle VC1 big That is, the diameter of the virtual circle VC1, which is the inner diameter (maximum value) of the gear body 22. The inner diameter of the outer ring 62A Small. Therefore, on the inner circumferential surface of the main body 18, between the bottom of the plurality of pin retaining grooves 223 in the inner circumferential surface 221 of the gear body 22 and the outer ring 62A, as... Figure 16 As shown, this creates a height difference D1. The height difference D1 is preferably, for example, the diameter of pin 23. (Refer to Figure 14 one-twelfth More than twice as much Below. As an example, in the diameter of pin 23... When the height difference is around 2.5mm, the height D1 of the height difference is preferably 0.2mm or more and 0.5mm or less. This height difference can prevent interference between the pin 23 held by the pin retaining groove 223 and the inner circumferential surface 620 of the outer ring 62A.

[0196] Furthermore, in this embodiment, the outer diameter of the inner ring 61A (the first inner ring 601 and the second inner ring 602) The diameter of the virtual circle VC1 Smaller. That is, the diameter of the virtual circle VC1. Compared to the outer diameter of inner ring 61A Large, and the inner diameter of the outer ring is 62A. The diameter of the virtual circle VC1 Large. In other words, the diameter of the virtual circle VC1. The outer diameter of the inner ring 61A The inner diameter of the outer ring 62A The values ​​between

[0197] In addition, such as Figure 16 As shown, a retaining recess 67 is disposed between the inner circumferential surface 620 of the outer ring 62A and the inner circumferential surface 221 of the gear body 22. The retaining recess 67 is formed by a groove disposed circumferentially throughout the outer ring 62A. The retaining recess 67 is formed such that, for example, surface tension can retain the size and shape of the lubricant. That is, the retaining recess 67 functions as an "oil accumulation point" for accumulating lubricant (lubricating oil). In this embodiment, the gear body 22 and the outer ring 62A are configured such that the gear body 22 is the input side of the rotating shaft Ax1 ( Figure 16 (on the left side), and the outer ring 62A is the output side of the rotating shaft Ax1 ( Figure 16 (on the right side). Therefore, the inner circumferential surface 221 of the gear body 22, the retaining recess 67 and the inner circumferential surface 620 of the outer ring 62A are arranged from the input side of the rotating shaft Ax1 in the order of the inner circumferential surface 221 of the gear body 22, the retaining recess 67 and the inner circumferential surface 620 of the outer ring 62A.

[0198] In this embodiment, as an example, such as Figure 16 As shown, the cross-sectional shape of the retaining recess 67, which is orthogonal to the circumferential direction of the outer ring 62A, is rectangular. The depth D2 (distance from the inner circumferential surface 620 of the outer ring 62A) and the width D3 of the retaining recess 67 are both greater than the height difference D1. The depth D2 and width D3 of the retaining recess 67 are preferably the diameters of the pin 23. one-tenth More than twice Below. As an example, in the diameter of pin 23... With a diameter of approximately 2.5mm, the depth D2 and width D3 of the recess 67 are preferably 0.25mm or more and 5.0mm or less. Figure 16 In this example, the depth D2 of the retaining recess 67 is greater than the width D3 of the retaining recess 67, but it is not limited to this example. The depth D2 of the retaining recess 67 can also be less than or equal to the width D3. Furthermore, the cross-sectional shape of the retaining recess 67 is not limited to a rectangular shape, but can also be a semi-circular shape, a triangular shape, or other polygonal shapes, etc.

[0199] In this embodiment, the gear device 1A further includes a path for lubricant connecting the retaining recess 67 to at least one of the plurality of inner pins 4, the plurality of pins 23, and the plurality of rolling elements 63. That is, the retaining recess 67, acting as an "oil accumulation point," is connected to at least one of the plurality of inner pins 4, the plurality of pins 23, and the plurality of rolling elements 63 via the lubricant path. Thus, the lubricant held in the retaining recess 67 supplies lubricant to at least one of the plurality of inner pins 4, the plurality of pins 23, and the plurality of rolling elements 63, ensuring smooth operation of the inner pins 4, pins 23, and rolling elements 63. In this embodiment, the retaining recess 67 is located on the lubricant circulation path RL1, thereby using a portion of the circulation path RL1 as a "lubricant" path to supply lubricant within the retaining recess 67 to at least one of the inner pins 4, pins 23, and rolling elements 63. Particularly in this embodiment, as... Figure 16 As shown, since the inner pin 4, pin 23 and rolling element 63 are all located on the circulation path RL1, the lubricant held in the retaining recess 67 can be supplied to all of the inner pin 4, pin 23 and rolling element 63.

[0200] In this embodiment, in particular, the rolling element 63 is located on the circulation path RL1. Therefore, when the bearing member 6A actuates, the rolling element 63 rotates, thereby functioning as a pump to actively circulate the lubricant within the lubricant holding space 17 via the circulation path RL1. Especially since the dividing surfaces of the first inner ring 601 and the second inner ring 602 are positioned facing (opposite to) the rolling element 63, the rolling element 63 functions efficiently as a pump when it rotates. As a result, the lubricant within the lubricant holding space 17 circulates easily, and even during long-term use of the gear assembly 1A, the lubricant easily spreads throughout the entire lubricant holding space 17, making it difficult for adverse conditions such as a decrease in transmission efficiency in the gear assembly 1A to occur.

[0201] <Example>

[0202] like Figure 17As shown, the gear device 1A of this embodiment, together with the wheel body 102, constitutes the wheel device W1. In other words, the wheel device W1 of this embodiment includes the gear device 1A and the wheel body 102. The wheel body 102 rolls on the travel surface by the rotation output when the plurality of inner pins 4 rotate relative to the gear body 22. In this embodiment, the main body 18 and the cover 19, which are "rotating members" in the housing 10 that constitutes the outer contour of the gear device 1, constitute the wheel body 102. That is, in the wheel device W1 of this embodiment, the gear device 1A rotates as input rotation of the eccentric shaft 7 and rotates as output rotation of the rotating member (main body 18, etc.) to which the gear body 22 is fixed, thereby rotating the wheel body 102 and rolling on the travel surface. Here, a tire 103, for example made of rubber, is fitted on the outer peripheral surface of the main body 18, which is the contact surface of the wheel body 102 that contacts the travel surface, i.e., the contact surface.

[0203] The wheel assembly W1 configured in this way is used with the inner ring 61A fixed to the hub member 104, which serves as a fixed member. Thus, by rotating the eccentric shaft 7, the rotating member (wheel body 102) rotates relative to the fixed member (hub member 104), thereby rotating the wheel body 102. In this embodiment, as an example, the wheel assembly W1 uses multiple bolts 66 to fix the inner ring 61A (first inner ring 601 and second inner ring 602) to the hub member 104. In this case, it is preferable that the second inner ring 602 of the inner ring 61A is fixed to the hub member 104, etc.

[0204] Here, in the case where the gear device 1A is used for the wheel device W1, the gear device 1A is used essentially in an orientation where the rotating shaft Ax1 is along the horizontal plane. Therefore, through the circulation path RL1 (refer to...) Figure 16 The circulating lubricant is also easily supplied to the periphery of the eccentric shaft 7, including the eccentric bearing 5 (rolling element 53) and the second bearing 92. That is, a portion of the lubricant circulating through the circulation path RL1 is easily supplied to the eccentric bearing 5 and the second bearing 92, etc., through the gap between the planetary gear 3 (second planetary gear 302) and the first inner ring 601 under the influence of gravity. Therefore, even when the eccentric shaft 7 rotates at high speed and the lubricant splashes to the outer periphery due to centrifugal force, the lubricant can still be supplied to the periphery of the eccentric shaft 7 through the circulation path RL1, thereby easily maintaining the smooth rotation of the eccentric shaft 7.

[0205] Furthermore, the wheel assembly W1 using gear unit 1A is applied to vehicles such as Automated Guided Vehicles (AGVs). That is, the wheel assembly W1 is mounted on a hub member 104 located on the vehicle body, and the wheel body 102 rotates to roll on the travel surface, thereby allowing the vehicle to travel on a flat travel surface formed by the bottom surface, etc. As an example, multiple (e.g., four) gear units 1A are mounted on the vehicle body, and each gear unit 1A is driven by a different drive source, thus employing a "hub motor" layout. Therefore, the drive source rotates the eccentric shaft 7 of the wheel assembly W1 around the rotation axis Ax1, causing the planetary gear 3 to oscillate. As a result, the rotation generated by the drive source (input rotation) is reduced at a relatively high reduction ratio in the gear unit 1A, thereby causing the wheel body 102 to rotate with a relatively high torque.

[0206] However, in this embodiment, the outer peripheral surface 680 of the outer ring 62A constitutes a pressure-bearing surface that withstands stress greater than that of the outer peripheral surface 224 of the gear body 22. In other words, a stress greater than that of the outer peripheral surface 224 of the gear body 22 acts on the outer peripheral surface 680 (pressure-bearing surface) of the outer ring 62A from the outside. Especially when the gear device 1A is used for a wheel device W1, etc., the outer peripheral surface 680 of the outer ring 62A is preferably configured to withstand stress greater than that of the outer peripheral surface 224 of the gear body 22. The gear body 22 has a relatively large clearance with the planetary gear 3, allowing the planetary gear 3 to revolve (oscillate) inside the gear body 22. In contrast, the outer ring 62A only needs to allow the inner ring 61A to rotate inside it, and has a relatively small clearance with the inner ring 61A. That is, compared to the gear body 22, the outer ring 62A is a solid structure that is close to being blocked inside, and therefore has high rigidity against radial external forces. Therefore, by setting the outer peripheral surface 680 of the outer ring 62A as the pressure-bearing surface, the high-rigidity outer ring 62A side can withstand the stress from the outside, thereby increasing the stress resistance of the gear device 1A as a whole.

[0207] More specifically, the stress from the outer casing fitted to the outer periphery of the outer ring 62A acts on the pressure-bearing surface (outer peripheral surface 680 of the outer ring 62A). Here, the tire 103 is an example of an outer casing fitted to the outer periphery of the outer ring 62A. That is, when the tire 103 is assembled to fit to the outer periphery of the main body 18, the stress (fitting pressure) acting on the main body 18 from the tire 103 on the outer ring 62A is greater than that on the gear body 22. Specifically, for example... Figure 17As shown, by providing a spacer 68 at a location corresponding to the outer ring 62A on the outer peripheral surface of the main body 18, the outer diameter of the main body 18 at the outer ring 62A is larger than that at the gear body 22. Therefore, when the tire 103, which serves as an outer casing, is fitted onto the main body 18, the stress from the tire 103 is greater on the outer ring 62A side than on the gear body 22 side. However, the structure is not limited to the provision of the spacer 68; for example, the same effect can be achieved by reducing the outer diameter of the gear body 22, or by making the inner diameter of the outer casing (tire 103, etc.) on the outer ring 62A side smaller than that on the gear body 22 side.

[0208] Alternatively, the gear assembly 1A can be configured such that, even when the stress from the outer casing is the same at the outer peripheral surface 680 of the outer ring 62A and the outer peripheral surface 224 of the gear body 22, the reaction force from the ground, such as the travel surface, is increased on the outer peripheral surface 680 side of the outer ring 62A, which is the pressure-bearing surface. Specifically, for example, when using the gear assembly 1A as the wheel assembly W1, the reaction force from the ground, such as the travel surface, due to the adjustment of the camber angle is increased on the outer ring 62A side than on the gear body 22 side. In this case, a ground pressure from the ground surface acts on the pressure-bearing surface (the outer peripheral surface 680 of the outer ring 62A).

[0209] Furthermore, the gear device 1A of this embodiment is not limited to the wheel device W1. As explained in the basic structure, it can also be applied to robots such as horizontal multi-joint robots (selective compliant assembly manipulator type robots).

[0210] <Variation Example>

[0211] Implementation method 1 is merely one of many embodiments of this disclosure. Implementation method 1 can be modified in various ways, such as by design, to achieve the objectives of this disclosure. Furthermore, the accompanying drawings referenced in this disclosure are schematic diagrams, and the size and thickness ratios of the constituent elements shown may not reflect actual dimensional ratios. Hereinafter, variations of implementation method 1 are listed. The variations described below can be appropriately combined and applied.

[0212] For domestic sales 4, it is sufficient to connect the first inner ring 601, which forms the first inner ring 601 and the second inner ring 602, or it can be as follows: Figure 18A and Figure 18B As shown, a pin 4 is inserted into part or all of the second inner ring 602. Figure 18A In the example, the inner pin 4, which passes through the first inner ring 601, is inserted into the middle of the second inner ring 602, extending the retaining hole 611 to a portion of the second inner ring 602 in a direction parallel to the rotation axis Ax1. Figure 18BIn the example, the retaining hole 611 is formed to pass through both the first inner ring 601 and the second inner ring 602 in a direction parallel to the rotation axis Ax1, and the inner pin 4 that passes through the first inner ring 601 also passes through the second inner ring 602.

[0213] In embodiment 1, two types of gear devices 1A are illustrated with planetary gears 3, but gear device 1A may also include three or more planetary gears 3. For example, when 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. Moreover, gear device 1A may also include only one planetary gear 3.

[0214] Furthermore, the plurality of inner pins 4 are each configured, at least a portion of which is axially aligned with the bearing member 6A at the same position as the bearing member 6A; this is not a necessary structure in the gear assembly 1A. That is, the gear assembly 1A only needs to include the bearing member 6A, the internal gear 2, the planetary gear 3, and the plurality of inner pins 4. The bearing member 6A has an outer ring 62A and an inner ring 61A disposed inside the outer ring 62A. The inner ring 61A is supported so as to be rotatable relative to the outer ring 62A. The gear body 22 of the internal gear 2 is fixed to the outer ring 62A. The plurality of inner pins 4 are each held in a rotatable state within the inner ring 61A. Here, the plurality of inner pins 4 may be arranged side-by-side (opposite) to the bearing member 6A axially.

[0215] Furthermore, the number of internal pins 4, the number of pins 23 (the number of teeth of internal teeth 21), and the number of teeth of external teeth 31 described in Embodiment 1 are merely examples and can be appropriately changed.

[0216] Furthermore, the bearing component 6A is not limited to crossed roller bearings, and can be a deep groove ball bearing or an angular contact ball bearing, etc. However, the bearing component 6A is preferably a four-point contact ball bearing, etc., which can withstand radial loads, thrust loads (in the direction along the rotation axis Ax1), and bending forces (bending moment loads) on the rotation axis Ax1.

[0217] Furthermore, the eccentric bearing 5 is not limited to roller bearings; for example, it can be a deep groove ball bearing or an angular contact ball bearing.

[0218] Furthermore, the materials of the various components of the gear device 1A are not limited to metal; for example, they can be resins such as engineering plastics.

[0219] Furthermore, the gear device 1A is only required to output the relative rotation between the inner ring 61A and the outer ring 62A of the bearing member 6A, and is not limited to outputting the rotational force of the outer ring 62A. For example, the rotational force of the inner ring 61A, which rotates relative to the outer ring 62A, can also be output.

[0220] In addition, lubricants are not limited to liquid substances such as lubricating oil (oil), but can also be gel-like substances such as lubricating grease.

[0221] Alternatively, the gear assembly 1A may include internal rollers. That is, in the gear assembly 1A, it is not necessary for each of the multiple internal pins 4 to directly contact the inner circumferential surface 321 of the internal pin hole 32; internal rollers may be sandwiched between each of the multiple internal pins 4 and the internal pin hole 32. In this case, the internal rollers are assembled to the internal pins 4 and can rotate about the internal pins 4 as an axis.

[0222] Furthermore, each of the multiple inner pins 4 only needs to be held in a self-rotating state within the inner ring 61A; it is not necessary for each of the multiple inner pins 4 to be directly held by the inner ring 61A. For example, each of the multiple inner pins 4 can be indirectly held by the inner ring 61A by inserting it into a holding hole formed in an output shaft or bracket integrated with the inner ring 61A.

[0223] Furthermore, the positioning of multiple inner pins 4 relative to the support body 8 in both the circumferential and radial directions is not necessary in the gear device 1A. For example, the support body 8 may have a slit-shaped support hole 82 extending radially, with the multiple inner pins 4 positioned relative to the support body 8 only in the circumferential direction. Conversely, the support body 8 may also have multiple inner pins 4 positioned relative to the support body 8 only in the radial direction.

[0224] Furthermore, the gear assembly 1A only needs to employ at least one of drilling the inner ring 61A of the bearing member 6A and drilling the outer ring 62A; it is not necessary to employ both. That is, the gear assembly 1A can employ either the case where the inner ring 61A has a first inner ring 601 and a second inner ring 602 (for drilling the inner ring 61A) or the case where the outer ring 62A is seamlessly and continuously disposed with the gear body 22 (for drilling the outer ring 62A).

[0225] Furthermore, since gear assembly 1A only requires drilling of the inner ring 61A and the outer ring 62A, other structural elements can be appropriately omitted or modified from the basic structure. For example, in gear assembly 1A, similar to the first related technology, the inner pins 4 can also be held in a state pressed into the inner ring 61A (or a bracket integrated with the inner ring 61A). In this case, each of the multiple inner pins 4 is held in a state where it cannot rotate relative to the inner ring 61A. Alternatively, each of the multiple inner pins 4 can be positioned axially in the same position as the bearing member 6A. Or, similar to the second related technology, the multiple inner pins 4 can be held solely by the inner ring 61A (or a bracket integrated with the inner ring 61A). In this case, the support body 8 can be omitted. Furthermore, even when a support body 8 is provided that supports (bundles) multiple inner pins 4, it is not necessary for the support body 8 to restrict its position by having its outer peripheral surface 81 contact the multiple pins 23; the outer peripheral surface 81 of the support body 8 can be away from the multiple pins 23.

[0226] Furthermore, regarding the study of the inner ring 61A, the gear device 1A only needs the inner ring 61A to have a first inner ring 601 and a second inner ring 602. For example, the inner ring 61A can be divided into three or more parts. That is, as an example, the inner ring 61A can have a third inner ring in addition to the first inner ring 601 and the second inner ring 602, and thus be divided into three parts.

[0227] Furthermore, the multiple holes for pressing in the multiple locating pins 65 only need to be formed from the first inner ring 601 to the second inner ring 602, and do not need to extend through the inner ring 61A in a direction parallel to the rotation axis Ax1. For example, the locating pins 65 can be pressed into holes formed from the opposing surface 602A side of the second inner ring 602 opposite to the first inner ring 601 to the middle of the thickness of the second inner ring 602. In this case, leakage of lubricant through the holes for pressing in the locating pins 65 can be prevented.

[0228] Furthermore, regarding the design of the outer ring 62A, the outer ring 62A of the bearing component 6A may not be completely seamless with the gear body 22 in a direction parallel to the rotation axis Ax1. That is, the manufacturing method of the gear device 1A only needs to include a process of integrally forming the outer ring 62A and the gear body 22 by processing a base material. Specifically, for example, the outer ring 62A and the gear body 22 can be integrally formed by processing a base material into which two metal blocks are joined (integrated) by pressing or bonding. In this case, a seam is formed at the joint of the two metal blocks, so although it is not completely seamless, the same effect as a seamless outer ring 62A and gear body 22 can be expected.

[0229] (Implementation Method 2)

[0230] like Figure 19A and Figure 19B As shown, the shape of the inner ring 61A of the bearing member 6A of the internal meshing planetary gear device 1B (hereinafter also simply referred to as "gear device 1B") in this embodiment is different from that of the gear device 1A in Embodiment 1. Figure 19B Is only shown Figure 19A A diagram showing the main portion of the first inner ring 601 of the A1-A1 line section. Hereinafter, for structures identical to those in Embodiment 1, the same reference numerals will be used, and descriptions will be omitted as appropriate.

[0231] In the gear device 1B of this embodiment, an enlarged diameter portion 691 is formed on the surface of the first inner ring 601 opposite to the second inner ring 602, which expands the opening area of ​​each of the plurality of retaining holes 611. Specifically, as Figure 19A As shown, the expanded diameter section 691 is located on the input side of the rotation axis Ax1 of the first inner ring 601 ( Figure 19A The left side of the retaining hole 611 is formed at the chamfered periphery of the opening. Here, the enlarged diameter portion 691 is formed in a conical shape (C-shaped surface) such that the opening area of ​​the retaining hole 611 increases further away from the second inner ring 602. In this embodiment, such enlarged diameter portions 691 are formed separately for all retaining holes 611. The enlarged diameter portion 691 is not limited to a conical shape (C-shaped surface); for example, it can also be a curved R-shaped surface (rounded corner) or a stepped countersunk hole shape, etc.

[0232] By forming such an enlarged diameter portion 691, at least in the opening surfaces of the plurality of retaining holes 611 opposite to the second inner ring 602, the gap between the retaining hole 611 and the inner pin 4 is enlarged. As a result, the gap between the inner circumferential surface of the retaining hole 611 and the inner pin 4, created by the enlarged diameter portion 691, functions as an "oil reservoir" for pre-accumulating lubricant (lubricating oil). The enlarged diameter portion 691 is continuous with the retaining hole 611, so the lubricant accumulated in the enlarged diameter portion 691 is introduced into the gap between the inner circumferential surface of the retaining hole 611 and the inner pin 4 due to, for example, capillary action, thus ensuring smooth rotation (self-rotation) of the inner pin 4.

[0233] In addition, such as Figure 20 As shown, the enlarged diameter section 691, which serves as an "oil accumulation point," is located on the lubricant circulation path RL1. Therefore, by using a portion of the circulation path RL1 as a "lubricant" path, the lubricant within the enlarged diameter section 691 can be supplied to at least one of the pins 23 (other than the inner pin 4) and the rolling elements 63. Particularly in this embodiment, as... Figure 20 As shown, pin 23 and rolling element 63 are both located on circulation path RL1, so the lubricant held in the expanded diameter section 691 can be supplied to both pin 23 and rolling element 63.

[0234] In addition, in this embodiment, such as Figure 19A and Figure 19B As shown, a connecting groove 692 is formed on the opposing surfaces 601A and 602A of at least one of the first inner ring 601 and the second inner ring 602, opposite to the other. The connecting groove 692 connects the space accommodating each of the plurality of rolling elements 63 to each of the plurality of retaining holes 611. That is, the connecting groove 692 is provided on at least one side of the opposing surfaces 601A and 602A, which are the dividing surfaces of the first inner ring 601 and the second inner ring 602, and connects the space accommodating each of the rolling elements 63 between the inner ring 61A and the outer ring 62A to the retaining holes 611. In this embodiment, as an example, the connecting groove 692 is formed radially along the inner ring 61A on the opposing surface 601A of the first inner ring 601 opposite to the second inner ring 602. In this embodiment, such connecting grooves 692 are formed respectively corresponding to all the retaining holes 611.

[0235] The connecting groove 692 functions as a path for lubricant (lubricating oil) to pass through. In this embodiment, as... Figure 20 As shown, the connecting groove 692 forms part of the lubricant circulation path RL1. In this embodiment, as an example, such as Figure 19B As shown, the cross-sectional shape of the connecting groove 692, which is radially orthogonal to the inner ring 61A, is rectangular. The depth D4 (from the opposing surface 601A) and width D5 of the connecting groove 692 are preferably the diameters of the pin 23. one-tenth More than twice Below. As an example, in the diameter of pin 23... When the diameter is approximately 2.5mm, the depth D4 and width D5 of the connecting groove 692 are preferably 0.25mm or more and 5.0mm or less. Figure 20 In this example, the depth D4 of the connecting groove 692 is smaller than the width D5 of the connecting groove 692, but it is not limited to this example. The depth D4 of the connecting groove 692 can be greater than the width D5. In addition, the cross-sectional shape of the connecting groove 692 is not limited to a rectangular shape, but can be a semi-circular shape, a triangular shape, or other polygonal shapes, etc.

[0236] By providing such a connecting groove 692, the lubricant can easily circulate within the lubricant holding space 17. Specifically, the connecting groove 692 connects to the space between the inner ring 61A and the outer ring 62A that houses the rolling element 63. Therefore, when the bearing member 6A actuates and the rolling element 63 rotates, the rolling element 63 functions as a pump, enabling the lubricant within the lubricant holding space 17 to circulate actively via the connecting groove 692. As a result, the lubricant in the lubricant holding space 17 circulates easily, and even during long-term use of the gear unit 1B, the lubricant easily permeates the entire lubricant holding space 17, making it difficult for adverse conditions such as a decrease in transmission efficiency in the gear unit 1B to occur.

[0237] Furthermore, by providing the connecting groove 692, it is also expected that the internal pressure in the space between the oil seal 16 and the rolling element 63 can be reduced. That is, the space between the oil seal 16 and the rolling element 63 is connected to the retaining hole 611 through the connecting groove 692, thereby expanding the space between the oil seal 16 and the rolling element 63. Therefore, when the rolling element 63 functions as a pump, it helps to suppress the rise of internal pressure. As a result of suppressing the rise of internal pressure in the lubricant retaining space 17, for example, it is difficult for lubricant leakage caused by exceeding the oil seal 16 to occur.

[0238] As a variation of Embodiment 2, the connecting groove 692 may be formed on the opposing surfaces 601A and 602A of the first inner ring 601 and the second inner ring 602. Alternatively, the connecting groove 692 may be formed only on the opposing surface 602A of the second inner ring 602.

[0239] As another variation of Embodiment 2, the enlarged diameter portion 691 and the connecting groove 692 can be used separately. That is, the gear device 1B may have only the enlarged diameter portion 691 in the enlarged diameter portion 691 and the connecting groove 692, or it may have only the connecting groove 692.

[0240] The structure of Embodiment 2 (including variations) can be appropriately combined with the structure (including variations) described in Embodiment 1.

[0241] (Summarize)

[0242] As described above, the first-form internal meshing planetary gear assembly (1, 1A, 1B) includes bearing members (6, 6A), internal gears (2), planetary gears (3), and multiple inner pins (4). The bearing members (6, 6A) have an outer ring (62, 62A), an inner ring (61, 61A) disposed inside the outer rings (62, 62A), and multiple rolling elements (63) disposed between the outer rings (62, 62A) and the inner rings (61, 61A). The inner rings (61, 61A) are supported so as to be able to rotate relative to the outer rings (62, 62A) about a rotation axis (Ax1). The internal gears (2) have internal teeth (21) and are fixed to the outer rings (62, 62A). The planetary gears (3) have external teeth (31) that partially mesh with the internal teeth (21). Multiple inner pins (4), when respectively inserted into multiple inner pin holes (32) formed in the planetary gear (3), revolve within the inner pin holes (32) and rotate relative to the internal gear (2). The inner rings (61, 61A) include a first inner ring (601) and a second inner ring (602) that are opposite each other in a direction parallel to the rotation axis (Ax1) and whose opposing surfaces (601A, 602A) are in contact with each other. The first inner ring (601) has multiple retaining holes (611) through which the multiple inner pins (4) pass in a direction parallel to the rotation axis (Ax1). Each of the multiple inner pins (4) is held in the inner ring (61, 61A) in a state where it can rotate.

[0243] According to this configuration, even a small gap will be generated between the first inner ring (601) and the second inner ring (602). Due to the existence of such a gap, lubricant can be easily supplied to the inner pin (4) through the gap. Therefore, compared with the case where the inner rings (61, 61A) are not divided into the first inner ring (601) and the second inner ring (602), even during long-term use of the internal meshing planetary gear unit (1, 1A, 1B), the lubricant can easily spread throughout the whole, and it is difficult for adverse conditions such as a decrease in transmission efficiency in the internal meshing planetary gear unit (1, 1A, 1B) to occur.

[0244] In the second form of the internal meshing planetary gear device (1, 1A, 1B), based on the first form, the end faces of the plurality of inner pins (4) are respectively in contact with the opposite face (602A) of the second inner ring (602) that is opposite to the first inner ring (601).

[0245] According to this configuration, the movement of the inner pin (4) in the direction parallel to the rotation axis (Ax1) is restricted by the second inner ring (602), and the leakage of lubricant through the retaining hole (611) can be suppressed.

[0246] In the third type of internal meshing planetary gear device (1, 1A, 1B), based on the first or second type, a gap is formed between the inner circumferential surface of each of the plurality of retaining holes (611) in the first inner ring (601) and the outer circumferential surface of each of the plurality of inner pins (4).

[0247] According to this configuration, the rotation of the inner pin (4) within the retaining hole (611) becomes smooth due to the lubricant.

[0248] In the fourth type of internal meshing planetary gear device (1, 1A, 1B), based on any of the first to third types, an enlarged diameter portion (691) is formed on the surface of the first inner ring (601) opposite to the second inner ring (602), which expands the opening area of ​​each of the plurality of retaining holes (611).

[0249] According to this configuration, the gap between the inner circumferential surface of the retaining hole (611) and the inner pin (4) generated by the enlarged diameter portion (691) functions as an "oil accumulation point" for pre-accumulating lubricant, thereby enabling the inner pin (4) to rotate (self-rotate) smoothly.

[0250] In the fifth type of internal meshing planetary gear assembly (1, 1A, 1B), based on any of the first to fourth types, a connecting groove (692) is formed on the opposing surfaces (601A, 602A) of at least one of the first inner ring (601) and the second inner ring (602) opposite to the other. The connecting groove (692) connects the space housing each of the multiple rolling elements (63) with each of the multiple retaining holes (611).

[0251] According to this configuration, the lubricant can be easily circulated through the connecting groove (692). In particular, by rotating the rolling element (63), which functions as a pump, the lubricant can be actively circulated through the connecting groove (692).

[0252] In the sixth form of the internal meshing planetary gear device (1, 1A, 1B), based on any of the first to fifth forms, the difference between the surface hardness of each of the multiple inner pins (4) and the surface hardness of the first inner ring (601) is HRC3 or less.

[0253] According to this configuration, even if the inner pin (4) inside the retaining hole (611) rotates, it is difficult to generate wear powder, etc., and it is easy to maintain the smooth rotation of the inner pin (4) for a long time.

[0254] In the seventh form of the internal meshing planetary gear device (1, 1A, 1B), based on any of the first to sixth forms, the surface hardness of each of the multiple inner pins (4) is in the range of HRC60±3.

[0255] According to this configuration, even if the inner pin (4) inside the retaining hole (611) rotates, it is difficult to generate wear powder, etc., and it is easy to maintain the smooth rotation of the inner pin (4) for a long time.

[0256] In the eighth form of the internal meshing planetary gear device (1, 1A, 1B), based on any of the first to seventh forms, a plurality of rolling elements (63) are located on a plane containing the first inner ring (601) opposite to the second inner ring (602) on a plane.

[0257] According to this configuration, when the rolling element (63) rotates, the rolling element (63) functions as a pump efficiently, making it easy for the lubricant to circulate.

[0258] In the ninth form of the internal meshing planetary gear device (1, 1A, 1B), based on the eighth form, the centers of the multiple rolling elements (63) in the direction parallel to the rotation axis (Ax1) are located on the same plane of the opposing surface (601A) of the first inner ring (601) opposite to the second inner ring (602).

[0259] According to this configuration, when the rolling element (63) rotates, the rolling element (63) functions as a pump efficiently, making it easy for the lubricant to circulate.

[0260] Based on any of the first to ninth forms, the tenth form of the internal meshing planetary gear device (1, 1A, 1B) also includes a lubricant circulation path (RL1). The lubricant circulation path (RL1) passes through at least the gap between the first inner ring (601) and the second inner ring (602), the space for each of the multiple rolling elements (63) that accommodates them, and each of the multiple retaining holes (611).

[0261] According to this configuration, the lubricant becomes easily circulated through the rolling elements (63) and the inner pin (4).

[0262] The structures of the second to tenth forms are not essential for the internal meshing planetary gear system (1, 1A, 1B) and can be omitted appropriately.

[0263] Explanation of reference numerals in the attached figures

[0264] 1. 1A, 1B Internal meshing planetary gear assembly

[0265] 2 Internal gears

[0266] 3 planetary gears

[0267] 4. Domestic sales

[0268] 6. 6A bearing components

[0269] 21 internal teeth

[0270] 31 external teeth

[0271] 32-hole inner pin

[0272] 61, 61A Inner Ring

[0273] 62, 62A outer ring

[0274] 63 rolling elements

[0275] 601 First Inner Circle

[0276] 601A (first inner ring) opposite face

[0277] 602 Second Inner Circle

[0278] 602A (Second Inner Ring) Opposite Side

[0279] 611 retaining hole

[0280] 691 Expanded Diameter Section

[0281] 692 connecting slot

[0282] Ax1 Rotational Axis

[0283] RL1 loop

[0284] Industrial applicability

[0285] According to embodiments of the present invention, an internal meshing planetary gear device is provided that is less prone to adverse conditions such as a decrease in transmission efficiency.

Claims

1. An internal meshing planetary gear device, wherein, include: A bearing component has an outer ring, an inner ring disposed inside the outer ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, the inner ring being supported so as to be rotatable relative to the outer ring about a rotation axis. An internal gear has internal teeth and is fixed to the outer ring. The internal gear has an annular gear body and multiple pins. The multiple pins are held on the inner circumferential surface of the gear body in a rotatable state to form the internal teeth. Planetary gears, having external teeth that partially mesh with the internal teeth; and Multiple inner pins, when respectively inserted into multiple inner pin holes formed in the planetary gear, revolve within the inner pin holes and rotate relative to the internal gear. The inner ring includes a first inner ring and a second inner ring that are opposite each other in a direction parallel to the rotation axis and whose opposite surfaces are in contact with each other. The first inner ring has a plurality of retaining holes through which the plurality of inner pins pass in a direction parallel to the rotation axis. Each of the plurality of inner pins is held in the inner circle in a state that allows it to rotate on its own; A support body, the outer peripheral surface of which contacts the plurality of pins, the support body supporting the plurality of inner pins.

2. The internal meshing planetary gear device according to claim 1, wherein, The end faces of each of the plurality of inner pins are in contact with the opposite face of the second inner ring that is opposite to the first inner ring.

3. The internal meshing planetary gear device according to claim 1 or 2, wherein, A gap is formed between the inner peripheral surface of each of the plurality of retaining holes in the first inner ring and the outer peripheral surface of each of the plurality of inner pins.

4. The internal meshing planetary gear device according to any one of claims 1 to 3, wherein, An enlarged diameter portion is formed on the surface of the first inner ring opposite to the second inner ring, which expands the opening area of ​​each of the plurality of retaining holes.

5. The internal meshing planetary gear device according to any one of claims 1 to 4, wherein, A connecting groove is formed on the opposite surface of at least one of the first inner ring and the second inner ring, which connects the space accommodating each of the plurality of rolling elements to each of the plurality of retaining holes.

6. The internal meshing planetary gear device according to any one of claims 1 to 5, wherein, The difference between the surface hardness of each of the plurality of inner pins and the surface hardness of the first inner ring is less than HRC3.

7. The internal meshing planetary gear device according to any one of claims 1 to 6, wherein, The surface hardness of each of the plurality of inner pins is in the range of HRC60±3.

8. The internal meshing planetary gear device according to any one of claims 1 to 7, wherein, The plurality of rolling elements are located on a plane containing the opposing surface of the first inner ring, which is opposite to the second inner ring.

9. The internal meshing planetary gear device according to claim 8, wherein, The centers of the plurality of rolling elements in a direction parallel to the rotation axis are located on the same plane of the opposing surfaces of the first inner ring and the second inner ring.

10. The internal meshing planetary gear device according to any one of claims 1 to 9, wherein, The internal meshing planetary gear assembly further includes a lubricant circulation path, which passes at least through the gap between the first inner ring and the second inner ring, the space accommodating each of the plurality of rolling elements, and each of the plurality of retaining holes.

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