Internal gear planetary gear device and joint device for robots

Abstract

The present disclosure provides an internal meshing planetary gear device and a joint device for a robot that easily reduces loss generated when an internal pin rotates. An internal meshing planetary gear device (1A) includes a bearing member (6A), an internal gear (2), a planetary gear (3), a plurality of internal pins (4), a plurality of sets of rolling bearings (41, 42), and a circulation path (170). The plurality of internal pins (4) relatively rotate with respect to the internal gear (2) while orbiting within internal pin holes (32) in a state of being respectively inserted in the plurality of internal pin holes (32) formed in the planetary gear (3). The plurality of sets of rolling bearings (41, 42) respectively hold the plurality of internal pins (4) at both sides in a direction parallel to a rotation axis (Ax1) with respect to the planetary gear (3). The circulation path (170) includes a gap between an inner circumferential surface of the internal pin hole (32) and the internal pin (4) and a raceway (404) of a rolling element (402) in the rolling bearing (41, 42). In the internal meshing planetary gear device (1A), a lubricant is circulated through the circulation path (170).

Description

Cross-references to related applications

[0001] This application is based on and claims priority to Japanese Patent Application No. 2021-164157, filed on October 5, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to internal meshing planetary gear devices and robot joint devices, and more specifically, to internal meshing planetary gear devices and robot joint devices in which a planetary gear with external teeth is disposed inside an internal gear having internal teeth. Background Technology

[0003] As a related technology, an internal meshing planetary gear device (structure) is known where the planetary gear (external gear) oscillates and rotates together with the input shaft, causing the external teeth of the subcycloidal tooth profile located on the outer periphery of the planetary gear to mesh with the internal teeth of the internal gear (for example, see Patent Document 1). In the internal meshing planetary gear device of the related technology, the rotation of the input shaft is reduced to a decelerated rotation (rotation) of the planetary gear and thus removed through the meshing of the external teeth of the planetary gear with the internal teeth (pin) of the internal gear.

[0004] In this internal meshing planetary gear assembly, an inner pin, which passes through the inner pin hole (clearance fitting hole) of the planetary gear, is rotatably fitted into the flange of the output shaft via a bushing. Thus, the rotation of the planetary gear absorbs its oscillation component through the gap between the inner pin hole and the inner pin, and only the rotation component is transmitted to the output shaft via the inner pin.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 05-044790 Summary of the Invention The technical problem that the invention aims to solve In the aforementioned related technologies, the output shaft (flange) is held in place by a bushing to allow the inner pin to rotate. However, when the inner pin rotates, friction occurs between the output shaft (flange) and the inner pin, which can result in power transmission losses. In particular, with long-term use of internal meshing planetary gear systems, losses due to friction increase, for example, due to lubricant deterioration, which also hinders the extension of the lifespan of the internal meshing planetary gear system.

[0006] The purpose of this disclosure is to provide an internally engaged planetary gear device and a joint device for robots that can easily reduce losses caused by the rotation of the inner pin.

[0007] Solutions for solving technical problems An internally meshing planetary gear assembly according to one embodiment of this disclosure includes a bearing component, an internal gear, a planetary gear, a plurality of inner pins, a plurality of sets of rolling bearings, and a circulation path. The bearing component has an outer ring and an inner ring disposed inside the outer ring, the inner ring being 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, respectively inserted into a plurality of inner pin holes formed in the planetary gear, rotate relative to the internal gear while revolving within the inner pin holes. The plurality of sets of rolling bearings hold the plurality of inner pins on both sides of the planetary gear in a direction parallel to the rotation axis. The circulation path includes the gap between the inner circumferential surface of the inner pin hole and the inner pin, and the raceways of the rolling elements in the rolling bearings. In the internally meshing planetary gear assembly, lubricant circulates through the circulation path.

[0008] One embodiment of the present disclosure includes a robot joint device comprising: the internally meshing planetary gear assembly, a first component fixed to the outer ring, and a second component fixed to the inner ring.

[0009] Invention Effects According to embodiments of this disclosure, an internal meshing planetary gear device and a joint device for robots can be provided that easily reduce losses caused by the rotation of the inner pin. Attached Figure Description

[0010] Figure 1 This is a perspective view showing the schematic configuration of an actuator containing the internal meshing planetary gear mechanism involved in the basic structure.

[0011] Figure 2 This is a schematic exploded perspective view of the same internal meshing planetary gear mechanism, viewed from the output side of the rotating shaft.

[0012] Figure 3 This is a schematic cross-sectional view of the same internal meshing planetary gear assembly.

[0013] Figure 4 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 3 Sectional view along line A1-A1.

[0014] Figure 5A This is a perspective view of the planetary gears of the same internal meshing planetary gear assembly, shown as a single unit.

[0015] Figure 5B This is a front view of the planetary gears of the same internal meshing planetary gear assembly, shown as a single unit.

[0016] Figure 6AThis is a perspective view of the bearing components of the same internal meshing planetary gear assembly shown as a single unit.

[0017] Figure 6B This is a front view of the bearing components of the same internal meshing planetary gear assembly, shown as a single unit.

[0018] Figure 7A This is a perspective view of the eccentric shaft of the same internal meshing planetary gear assembly shown in the figure.

[0019] Figure 7B This is a front view of the eccentric shaft of the same internal meshing planetary gear assembly shown as a single unit.

[0020] Figure 8A This is a perspective view of the support body of the same internal meshing planetary gear assembly shown as a single unit.

[0021] Figure 8B This is a front view of the support body of the same internal meshing planetary gear assembly shown as a single unit.

[0022] Figure 9 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 3 A magnified view of region Z1.

[0023] Figure 10 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 3 Sectional view along line B1-B1.

[0024] Figure 11 This is a schematic cross-sectional view of the internal meshing planetary gear device of the first embodiment.

[0025] Figure 12 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 13 Sectional view along line B1-A1.

[0026] Figure 13 This is a side view of the same internal meshing planetary gear assembly, viewed from the input side of the rotating shaft.

[0027] Figure 14 This is a side view of the same internal meshing planetary gear assembly, viewed from the output side of the rotating shaft.

[0028] Figure 15 This is a schematic cross-sectional view showing the state of the internal meshing planetary gear assembly with the cover and oil seal removed.

[0029] Figure 16 This is a side view, taken from the input side of the rotating shaft, showing the internal meshing planetary gear assembly with the cover and oil seal removed.

[0030] Figure 17This is a side view, taken from the output side of the rotating shaft, showing the internal meshing planetary gear assembly with the cover and oil seal removed.

[0031] Figure 18 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 11 Sectional view along line A1-A1.

[0032] Figure 19 This is an example of an internal meshing planetary gear assembly, as shown above. Figure 11 Sectional view along line B1-B1.

[0033] Figure 20 This is an explanatory diagram showing the configuration of the rolling bearings in the same internal meshing planetary gear assembly.

[0034] Figure 21 This is a schematic cross-sectional view showing the circulation path of the lubricant in the same internal meshing planetary gear assembly.

[0035] Figure 22 This is an illustrative diagram schematically representing the flow of lubricant in the same internal meshing planetary gear assembly, focusing on the third region.

[0036] Figure 23 This is a schematic diagram illustrating the circulation of lubricant in the circulation path via a pump function in the same internal meshing planetary gear assembly.

[0037] Figure 24 This is a magnified schematic cross-sectional view of the area near the third region of the same internal meshing planetary gear assembly.

[0038] Figure 25 This is a schematic diagram illustrating the sequence of replacement of the inner pins in the same internal meshing planetary gear assembly.

[0039] Figure 26 This is a schematic diagram illustrating the replacement sequence of the rolling elements in the same internal meshing planetary gear assembly.

[0040] Figure 27 This is a schematic cross-sectional view of a robot joint device that uses the same internal meshing planetary gear mechanism.

[0041] Figure 28 This is a schematic cross-sectional view of an internal meshing planetary gear assembly used for comparison with the above-mentioned internal meshing planetary gear assembly and its variant.

[0042] Figure 29 This is a schematic cross-sectional view of the internal meshing planetary gear device of the second embodiment. Detailed Implementation

[0043] (Basic Structure) (1) Summary The following is for reference Figures 1-3 The general outline of the internal meshing planetary gear device 1 involved in this basic structure will be described. The accompanying drawings referenced in the embodiments of this disclosure are schematic diagrams, and the size and thickness ratios of the constituent elements in the drawings may not necessarily reflect the 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 shown schematically for illustration only and are not limited to the shapes shown in the figure.

[0044] The basic structure involves an internal meshing planetary gear assembly 1 (hereinafter also referred to as "gear assembly 1"), which is a gear assembly including an internal gear 2, planetary gears 3, and multiple inner pins 4. In this gear assembly 1, the planetary gears 3 are arranged inside the annular internal gear 2, and an eccentric bearing 5 is arranged inside the planetary gears 3. The eccentric bearing 5 has an eccentric inner ring 51 and an eccentric outer ring 52, with the eccentric inner ring 51 surrounding a central ring C1 (see [reference needed]). Figure 3 The rotation axis Ax1 is deviated from (see Figure 3 The planetary gear 3 oscillates due to the rotation (eccentric motion) of the inner ring 51. The inner ring 51 of the eccentric gear rotates about the axis of rotation Ax1, for example, by rotating the eccentric shaft 7 inserted into the inner ring 51. Additionally, the internal meshing planetary gear assembly 1 also includes a bearing component 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 to be able to 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, the planetary gear 3 is internally connected to the internal gear 2 on the inner side, 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 external teeth 31 moves in the circumferential direction 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) with the relative rotation of the two gears. As a result, a rotational output that is reduced at a higher reduction ratio is obtained from planetary gear 3, corresponding to the difference in the number of teeth between the two gears.

[0046] This gear assembly 1 is used to extract the rotation of the planetary gear 3, corresponding to its rotational component, as the rotation of an output shaft integrated with the inner ring 61 of the bearing component 6, for example. Thus, the gear assembly 1 functions as a gear assembly with a high reduction ratio, using the eccentric shaft 7 as the input side and the output shaft as the output side. Therefore, in the gear assembly 1 with this basic structure, in order to transmit the rotation of the planetary gear 3, corresponding to its rotational component, to the inner ring 61 of the bearing component 6, multiple inner pins 4 connect the planetary gear 3 and the inner ring 61. The multiple inner pins 4, each inserted into a plurality of inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 while rotating relative to the inner gear 2. That is, the inner pin holes 32 have a larger diameter than the inner pins 4, and the inner pins 4, when inserted into the inner pin holes 32, can move by revolving within the inner pin holes 32. Furthermore, the oscillation component of the planetary gear 3, i.e., the revolution component of the planetary gear 3, is absorbed by the clearance engagement between the inner pin holes 32 of the planetary gear 3 and the inner pins 4. In other words, the oscillation component of the planetary gear 3 is absorbed by the multiple inner pins 4 moving in a manner that revolves within the multiple inner pin holes 32. Therefore, the rotation (rotation component) of the planetary gear 3, other than the oscillation component (revolution component), is transmitted to the inner ring 61 of the bearing component 6 through the multiple inner pins 4.

[0047] However, in this gear assembly 1, the inner pin 4 revolves within the inner pin hole 32 of the planetary gear 3 while transmitting the rotation of the planetary gear 3 to multiple inner pins 4. Therefore, as a first related technology, it is known to use inner rollers mounted on the inner pins 4 and capable of rotating around the inner pins 4. That is, in the first related technology, the inner pin 4 is held in a state where it is pressed into the inner ring 61 (or a planetary carrier 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 related technology, inner rollers are used to reduce the losses caused by the frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4. However, if a structure including inner rollers is used as in the first related technology, the inner pin hole 32 needs to have a diameter that allows the inner pin 4 with the inner roller to revolve, making it difficult to miniaturize the inner pin hole 32. If miniaturization of the inner pin hole 32 is difficult, it will hinder the miniaturization of the planetary gear 3 (especially its small diameter), and consequently hinder the overall miniaturization of the gear assembly 1. The gear assembly 1 involved in this basic structure can provide an easily miniaturized internal meshing planetary gear assembly 1 through the following structure.

[0048] In other words, such as Figures 1-3As shown, the gear assembly 1 involved in this basic structure includes a bearing component 6, an internal gear 2, a planetary gear 3, and a plurality of inner pins 4. The bearing component 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 able to rotate 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, while being 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, the plurality of inner pins 4 are each held in a state where they can rotate on their own axis within the inner ring 61. Furthermore, at least a portion of each of the plurality of inner pins 4 is arranged in the same position as the bearing component 6 in the axial direction.

[0049] According to this method, multiple inner pins 4 are 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 capable of rotating 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 device 1 according to this basic structure, inner rollers are not necessary, which has the advantage of easy miniaturization. Moreover, at least a portion of each of the multiple inner pins 4 is arranged in the same position as the bearing member 6 in the axial direction, so the axial dimension of the gear device 1 in 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 (opposite) in the axial direction of the bearing member 6, in the gear device 1 according to this basic structure, the axial dimension of the gear device 1 can be reduced, thereby contributing to further miniaturization (thinning) of the gear device 1.

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

[0051] Furthermore, in this gear assembly 1, since the inner pins 4 need to revolve within the inner pin holes 32 of the planetary gear 3, as a second related technology, sometimes the multiple inner pins 4 are held only by the inner ring 61 (or a planetary carrier integrated with the inner ring 61). According to the second related technology, 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 reduced transmission efficiency. That is, the multiple inner pins 4 revolve within the inner pin holes 32 while rotating relative to the internal gear 2, thereby transmitting the rotational component of the planetary gear 3 to the inner ring 61 of the bearing component 6. At this time, if the centering accuracy of the multiple inner pins 4 is insufficient, the rotation axis of the multiple inner pins 4 will be offset or tilted relative to the rotation axis of the inner ring 61, resulting in a state of poor centering, which will lead to adverse conditions such as vibration and reduced transmission efficiency. The gear assembly 1 according to 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] In other words, such as Figures 1-3 As shown, the gear assembly 1 involved in 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, respectively inserted into multiple inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 while rotating 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 positioned by contacting the multiple pins 23 with its outer circumferential surface 81.

[0053] According to this method, multiple inner pins 4 are supported by an annular support body 8, thus binding the multiple inner pins 4 together and suppressing relative offset 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 limiting the position of the support body 8. In short, the support body 8 is centered by the multiple pins 23, resulting in the multiple inner pins 4 supported on the support body 8 also being centered by the multiple pins 23. Therefore, the gear device 1 based on this basic structure has the advantage of easily achieving improved accuracy in centering the multiple inner pins 4 and reducing the likelihood of adverse situations caused by poor centering of the multiple inner pins 4.

[0054] In addition, such as Figure 1As shown, the gear assembly 1 involved in this basic structure, together with the drive source 101, constitutes the actuator 100. In other words, the actuator 100 involved in 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 oscillates the planetary gear 3 by rotating the eccentric shaft 7 around the rotation axis Ax1.

[0055] (2) Definition In this embodiment of the disclosure, "ring-shaped" refers to a shape that forms a wrap around an enclosed space (region) on the inside, at least when viewed from above. It is not limited to a circular shape (ring-shaped) that is perfectly round when viewed from above; for example, it can also be an elliptical shape or a polygonal shape. Furthermore, for example, even a shape with a bottom, such as a cup, is included in "ring-shaped" as long as its peripheral walls are ring-shaped.

[0056] In this embodiment, "clearance fitting" refers to insertion with a clearance (gap), where the inner pin hole 32 is a hole for the inner pin 4 to engage with the clearance. That is, the inner pin 4 is inserted into the inner pin hole 32 with a sufficient space (gap) 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 can move within the inner pin hole 32 while inserted, i.e., 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, a gap, not necessarily a void, is required 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 in this gap.

[0057] In this embodiment of the disclosure, "revolution" refers to the rotation of an object around an axis of rotation other than the central axis passing through the object's center (center of gravity). When an object revolves, its center moves along a revolution track centered on the axis of rotation. Therefore, for example, when the object rotates around an eccentric axis parallel to the central axis passing through the object's center (center of gravity), the object revolves around the eccentric axis. As an example, the inner pin 4 rotates around an axis of rotation passing through the center of the inner pin hole 32 and revolves within the inner pin hole 32.

[0058] Furthermore, in this embodiment of the disclosure, one side of the rotating shaft Ax1 ( Figure 3 The left side of the axis (Ax1) is sometimes referred to as the "input side," while the other side of the axis (Ax1) is... Figure 3 The right side (of the image) is sometimes called the "output side". Figure 3In the example, rotation is applied 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 labels added for illustration only and are not intended to define the positional relationship between input and output as observed from the gear device 1.

[0059] In this embodiment of the disclosure, the term "rotation axis" refers to an imaginary axis (straight line) that serves as the center of rotational motion of the rotating body. That is, rotation axis Ax1 is an imaginary axis without a physical form. The inner ring 51 of the eccentric body rotates around rotation axis Ax1.

[0060] In this embodiment, "internal teeth" and "external teeth" do not refer to individual "teeth," but rather to a collection (group) of multiple "teeth." That is, the internal teeth 21 of the internal gear 2 are composed of a collection of multiple teeth arranged 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 arranged on the outer circumferential surface of the planetary gear 3.

[0061] (3) Structure The following is for reference Figures 1-8B The detailed structure of the internal meshing planetary gear device 1 involved in this basic structure is described.

[0062] Figure 1 This is a perspective view showing the schematic structure of the actuator 100, including the gear mechanism 1. Figure 1 The drive source 101 is shown schematically. Figure 2 This is a simplified exploded perspective view of the gear device 1 as observed 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 A1-A1 line sectional view. However, in Figure 4 In the text, for parts other than the eccentric shaft 7, section lines are omitted even in cross-sections. Additionally, 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 three-dimensional view and front view of the eccentric shaft 7 are shown 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.

[0063] (3.1) Overall structure like Figures 1-3 As shown, the gear assembly 1 involved in this basic structure includes an internal gear 2, a planetary gear 3, multiple inner pins 4, an eccentric bearing 5, a bearing assembly 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 materials of the internal gear 2, planetary gear 3, multiple inner pins 4, eccentric bearing 5, bearing assembly 6, eccentric shaft 7, and support body 8, which are components of the gear assembly 1, are stainless steel, cast iron, carbon steel for mechanical construction, chromium-molybdenum steel, phosphor bronze, or aluminum bronze, etc. The metals mentioned here include metals that have undergone surface treatments such as nitriding.

[0064] Furthermore, in this basic structure, as an example of gear device 1, an internal planetary gear device with a subcycloidal tooth profile is illustrated. That is, the gear device 1 involved in this basic structure includes an internal planetary gear 3 having a subcycloidal curved tooth profile.

[0065] 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 component 6 fixed to a fixed component 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 component (housing 10, etc.).

[0066] 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 a rotational force is extracted from the output shaft, which is integrated with the inner ring 61 of the bearing component 6, as output. In other words, the gear device 1 operates by using 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. Thus, in the gear device 1, an output rotation that is reduced at a higher reduction ratio relative to the input rotation can be obtained.

[0067] The drive source 101 is a power source such as a motor. The power generated by the drive source 101 is transmitted to the eccentric shaft 7 of the gear device 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.

[0068] Furthermore, in the gear device 1 involved in this basic structure, such as Figure 3As shown, the input-side rotation axis Ax1 and the output-side rotation axis Ax1 are located 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 to which the input rotation is applied, and the output-side rotation axis Ax1 is the rotation center of the inner ring 61 (and the output shaft) that generates the output rotation. That is, in the gear device 1, an output rotation that is reduced at a higher reduction ratio relative to the input rotation is obtained on the same axis.

[0069] like Figure 4 As shown, the internal gear 2 is an annular part 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 internal gear 2 on the inner circumferential surface of the annular internal gear 2. All the 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 in the direction of the rotation axis Ax1. The tooth lines of the internal teeth 21 are all parallel to the rotation axis Ax1. The dimension in the tooth line direction of the internal teeth 21 is slightly smaller than that in the thickness direction of the internal gear 2.

[0070] 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 internal teeth 21. In other words, the multiple pins 23 function as multiple teeth constituting the internal teeth 21. Specifically, as... Figure 2 As shown, multiple grooves are formed throughout the circumferential area of ​​the inner circumferential surface 221 of the gear body 22. All grooves are of the same shape and are evenly spaced. Each groove is parallel to the rotation axis Ax1 and extends along the entire thickness of the gear body 22. Multiple pins 23 are combined with the gear body 22 by being inserted into the grooves. Each pin 23 is held within its groove in a rotatable state. Furthermore, the gear body 22 (together with the outer ring 62) is fixed to the housing 10. Therefore, multiple fixing holes 222 for fixing are formed in the gear body 22.

[0071] like Figure 4 As shown, the planetary gear 3 is an annular part with external teeth 31. In this basic structure, the planetary gear 3 has an annular shape with 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 the 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 offset from the rotation axis Ax1 (see...). Figure 4 The planetary gear 3 has a specified thickness in 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 lines of the external teeth 31 are all 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.

[0072] Here, the planetary gear 3 is assembled 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. When 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 in the opening 33 of the planetary gear 3. Furthermore, by inserting the eccentric shaft 7 into the inner ring 51 of the eccentric bearing 5, the eccentric bearing 5 and the eccentric shaft 7 are combined with the planetary gear 3. With the eccentric bearing 5 and the eccentric shaft 7 combined with the planetary gear 3, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates around the rotation axis Ax1.

[0073] 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, and 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.

[0074] Furthermore, the pitch circle of the external tooth 31 is one rotation smaller than that of the internal tooth 21. Also, with the planetary gear 3 internally engaged with the internal gear 2, the center C1 of the pitch circle of the external tooth 31 is located a distance ΔL offset from the center of the pitch circle of the internal tooth 21 (rotation axis Ax1) (see...). Figure 4 The position of the external gear 31 and the internal gear 21 is such that, at least part of them are positioned opposite each other with a gap, and they are not completely meshed in the circumferential direction. However, the planetary gear 3 oscillates (revolves) around the rotation axis Ax1 inside the internal gear 2, so the external gear 31 and the internal gear 21 partially mesh. That is to say, 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.

[0075] Here, the number of teeth on the internal gear 21 of the internal gear 2 is N more than the number of teeth on the external gear 31 of the planetary gear 3 (N is a positive integer). In this basic structure, as an example, N is "1", and the number of teeth on the planetary gear 3 (external teeth 31) is "1" more than the number of teeth on 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 relative to the input rotation in the gear unit 1.

[0076] Furthermore, in this basic structure, for example, the thickness of the planetary gear 3 is smaller than the thickness of the gear body 22 of the internal gear 2. Additionally, the dimension of the external tooth 31 in the tooth line direction (parallel to the rotation axis Ax1) is smaller than the dimension of the internal tooth 21 in the tooth line 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 line of the internal tooth 21.

[0077] In this basic structure, as described above, the rotation of the planetary gear 3, corresponding to its rotational component, is taken out as the rotation (output rotation) of the output shaft integrated with the inner ring 61 of the bearing component 6. Therefore, the planetary gear 3 is connected to the inner ring 61 via multiple inner pins 4. Figure 5A and Figure 5B As shown, a plurality of inner pin holes 32 for inserting a plurality of inner pins 4 are formed on the planetary gear 3. 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 of the plurality of inner pin holes 32 has a circular opening and is a hole that passes through the planetary gear 3 along the thickness direction. The plurality of (here, 18) inner pin holes 32 are arranged at equal intervals in the circumferential direction on an imaginary circle concentric with the opening 33.

[0078] Multiple inner pins 4 are parts that connect the planetary gear 3 and the inner ring 61 of the bearing component 6. Each inner pin 4 is cylindrical. The diameter and length of the multiple inner pins 4 are common. 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 with a sufficient space allowance (clearance) between it and the inner circumferential surface 321 of the inner pin hole 32 (see...). Figure 4 ).

[0079] The bearing component 6 has an outer ring 62 and an inner ring 61, and is a part used to extract the output of the gear device 1 by rotating 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...). Figure 3 ).

[0080] like Figure 6A and Figure 6BAs shown, both the outer ring 62 and the inner ring 61 are annular parts. Both the outer ring 62 and the inner ring 61 are circular rings when viewed from above. The inner ring 61 is smaller than the outer ring 62 and is positioned inside the outer ring 62. Here, because the inner diameter of the outer ring 62 is larger than the outer diameter of the inner ring 61, a gap is created between the inner circumferential surface of the outer ring 62 and the outer circumferential surface of the inner ring 61.

[0081] The inner ring 61 has a plurality of retaining holes 611 into which a plurality of inner pins 4 are inserted. The number of retaining holes 611 is the same as the number of inner pins 4; in this basic structure, for example, there are 18 retaining holes 611. Figure 6A and Figure 6B As shown, multiple retaining holes 611 each have a circular opening and are holes that penetrate the inner ring 61 along the thickness direction. Multiple (here, 18) retaining holes 611 are arranged at equal intervals in the circumferential direction on an imaginary circle concentric with the outer circumference of the inner ring 61. The diameter of the retaining holes 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.

[0082] Furthermore, the inner ring 61 is integrated with the output shaft, and the rotation of the inner ring 61 is taken out 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...). Figure 2 In this basic structure, a plurality of output-side mounting holes 612 are arranged on an imaginary circle that is inside the plurality of retaining holes 611 and concentric with the outer periphery of the inner ring 61.

[0083] 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 in the figure... Figure 3 As shown, the outer ring 62 is fixed to the housing 10 by a fixing screw (bolt) 60 passing through the through hole 621 and the fixing hole 222 of the gear body 22, with the gear body 22 spaced between the outer ring 62 and the housing 10.

[0084] 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 in the circumferential direction of the outer ring 62. All of the multiple rolling elements 63 are metal parts of the same shape and are evenly spaced throughout the entire circumferential area of ​​the outer ring 62.

[0085] In this basic structure, bearing component 6 is, as an example, a crossed roller bearing. That is, bearing component 6 has cylindrical rollers as rolling elements 63. Furthermore, the axis of the cylindrical rolling element 63 has a 45-degree angle relative to a plane orthogonal to the rotation axis Ax1, and is orthogonal to the outer circumference of the inner ring 61. Additionally, a pair of adjacent rolling elements 63 in the circumferential direction of the inner ring 61 are arranged in an axially orthogonal orientation. Bearing component 6 constructed with such a crossed roller bearing can easily withstand radial loads, thrust loads (along the direction of the rotation axis Ax1), and bending forces (bending moment loads) against the rotation axis Ax1. Moreover, by using a single bearing component 6, it is possible to withstand these three types of loads, ensuring the necessary rigidity.

[0086] like Figure 7A and Figure 7B As shown, the eccentric shaft 7 is a cylindrical part. 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 a perfect circle in plan view. 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 a perfect circle in plan view. The center (central axis) of the eccentric portion 72 coincides with a center C1 that is offset from the rotation axis Ax1. Here, the distance ΔL between the rotation axis Ax1 and the center C1 (see...) Figure 7B The eccentricity of the eccentric portion 72 relative to the central portion 71 is eccentricity. The eccentric portion 72 forms a flange shape at the center of the central portion 71 along its length (axial direction), protruding from the outer circumference of the central portion 71. According to the above structure, the eccentric shaft 7 rotates (spins) about the rotation axis Ax1 via the central portion 71, and the eccentric portion 72 performs eccentric motion.

[0087] 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, in this shape, is combined with the eccentric bearing 5 in the planetary gear 3. Therefore, when the eccentric shaft 7 rotates with the eccentric bearing 5 and the eccentric shaft 7 combined in the planetary gear 3, the planetary gear 3 oscillates about the rotation axis Ax1.

[0088] Furthermore, the eccentric shaft 7 has a through hole 73 that extends through the shaft center portion 71 in the axial direction (length direction). The through hole 73 opens in a circular shape at both ends 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. For example, power cables and signal cables can pass through the through hole 73.

[0089] Furthermore, in this basic structure, a rotational force is applied as an input from the drive source 101 to the eccentric shaft 7. Therefore, multiple input-side mounting holes 74 are formed on the eccentric shaft 7 for mounting an input shaft connected to the drive source 101 (see [link to documentation]). Figure 7A and Figure 7BIn this basic structure, a plurality of input-side mounting holes 74 are arranged around the through hole 73 on one end face of the shaft portion 71 in the axial direction, and are arranged on an imaginary circle concentric with the through hole 73.

[0090] The eccentric bearing 5 has an outer eccentric ring 52 and an inner eccentric ring 51. It is a component used to absorb the rotational component of the eccentric shaft 7, transmitting only the oscillating component (revolutionary component) of the rotation of the eccentric shaft 7 (excluding its rotational component) to the planetary gear 3. 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...). Figure 3 ).

[0091] Both the outer eccentric ring 52 and the inner eccentric ring 51 are annular parts. Both have a circular shape 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. Because the inner diameter of the outer eccentric ring 52 is larger than the outer diameter of the inner eccentric ring 51, a gap is created between the inner circumferential surface of the outer eccentric ring 52 and the outer circumferential surface of the inner eccentric ring 51.

[0092] 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 circumferentially on the outer ring 52. All of the 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.

[0093] Here, the inner diameter of the inner ring 51 of the eccentric shaft is the same as the outer diameter of the eccentric portion 72 of 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. Furthermore, the outer diameter of the outer ring 52 of the eccentric shaft is the same as 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 inserted into the opening 33 of the planetary gear 3. In other words, the eccentric bearing 5, which is assembled with the eccentric portion 72 of the eccentric shaft 7, is housed in the opening 33 of the planetary gear 3.

[0094] 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. Furthermore, 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 line 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.

[0095] 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 about a rotation axis Ax1 that is offset 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, the planetary gear 3 is only transmitted to the eccentric gear 3 the rotational component of the eccentric shaft 7 other than its rotational component, that is, the oscillating component (revolutionary component) of the eccentric shaft 7. Therefore, with the eccentric bearing 5 and eccentric shaft 7 combined in the planetary gear 3, when the eccentric shaft 7 rotates, the planetary gear 3 oscillates about the rotation axis Ax1.

[0096] like Figure 8A and Figure 8B As shown, the support body 8 is formed in a ring shape and is a component that supports multiple inner pins 4. The support body 8 has multiple support holes 82 for the insertion of the multiple inner pins 4. The number of support holes 82 is the same as the number of inner pins 4; in this basic structure, for example, there are 18 support holes 82. Figure 8A and Figure 8B As shown, multiple support holes 82 each have a circular opening and are holes that penetrate the support body 8 along the thickness direction. Multiple (here, 18) support holes 82 are arranged at equal intervals in the circumferential direction on an imaginary circle concentric with the outer peripheral surface 81 of the support body 8. The diameter of the support holes 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 holes 82 is equal to the diameter of the retaining hole 611 formed in the inner ring 61.

[0097] like Figure 3As shown, the support body 8 is positioned opposite the planetary gear 3 from one side (input side) of the rotating shaft Ax1. The support body 8 functions by inserting multiple inner pins 4 into multiple support holes 82, binding the multiple inner pins 4. Furthermore, the support body 8 is positioned by contacting its outer peripheral surface 81 with multiple pins 23. Thus, the support body 8 is centered by the multiple pins 23, and consequently, the multiple inner pins 4 supported on the support body 8 are also centered by the multiple pins 23. The support body 8 is described in detail in section "(3.3) Support Body".

[0098] 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... 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, separated by an eccentric portion 72. Viewed from the eccentric portion 72, the first bearing 91 is positioned on the input side of the rotation axis Ax1. 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 component 6. Thus, the two portions of the shaft center portion 71 of the eccentric shaft 7 on both sides of the eccentric portion 72 in a direction parallel to the rotation axis Ax1 are held rotatably.

[0099] The housing 10 is cylindrical and has a flange 11 on the output side of the rotating shaft Ax1. Multiple mounting holes 111 for fixing the housing 10 itself are formed in the flange 11. Additionally, a bearing hole 12 is formed on the end face of the housing 10 on the output side of the rotating shaft Ax1. The bearing hole 12 has a circular opening. A first bearing 91 is mounted relative to the housing 10 by inserting it into the bearing hole 12.

[0100] Furthermore, a plurality of threaded holes 13 are formed on the end face of the output side of the rotating shaft Ax1 of the housing 10 and around the bearing hole 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 component 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 fastened to the threaded holes 13, thereby fixing the gear body 22 and the outer ring 62 relative to the housing 10.

[0101] In addition, such as Figure 3As shown, the gear assembly 1 involved in this basic structure also includes multiple oil seals 14, 15, 16, etc. Oil seal 14 is installed at the end of the eccentric shaft 7 located on the input side of the rotating shaft Ax1, blocking the gap between the housing 10 and the eccentric shaft 7 (shaft core 71). Oil seal 15 is installed at the end of the eccentric shaft 7 located on the output side of the rotating shaft Ax1, blocking the gap between the inner ring 61 and the eccentric shaft 7 (shaft core 71). Oil seal 16 is installed on the end face of the bearing assembly 6 on the output side of the rotating shaft Ax1, blocking 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...). 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. Furthermore, the lubricant retention space 17 houses a plurality of pins 23, planetary gears 3, eccentric bearings 5, support bodies 8, a first bearing 91, and a second bearing 92, etc.

[0102] Furthermore, lubricant is injected into the lubricant holding space 17. The lubricant is liquid and can flow within the lubricant holding space 17. Therefore, when using 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. "Gel-like" here refers to a state having intermediate properties between liquid and solid, including a colloid state composed of two phases: a liquid phase and a solid phase. For example, states such as emulsions where the dispersion medium is a liquid phase and the dispersed phase is a liquid phase, and suspensions where the dispersed phase is a solid phase, are called gels or sols and are included in "gel-like". Additionally, states where the dispersion medium is a solid phase and the dispersed phase is a liquid phase are also included in "gel-like". In this basic structure, as an example, the lubricant is a liquid lubricating oil.

[0103] In the gear assembly 1 of the described structure, by applying a rotational force as input to the eccentric shaft 7, the eccentric shaft 7 rotates around the rotation axis Ax1, thereby causing the planetary gear 3 to oscillate (revolve) around the rotation axis Ax1. At this time, the planetary gear 3 oscillates with its inner side engaged with the inner gear 2 and 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 in the circumferential direction of the inner gear 2. As a result, a relative rotation corresponding to the difference in the number of teeth between the planetary gear 3 and the inner gear 2 is generated between the two gears (inner gear 2 and planetary gear 3). Furthermore, the rotation of the planetary gear 3 (rotation component), excluding the oscillation component (revolution component), is transmitted to the inner ring 61 of the bearing component 6 through multiple inner pins 4. As a result, a rotational output that is reduced in speed at a higher reduction ratio corresponding to the difference in the number of teeth between the two gears is obtained from the output shaft integrated with the inner ring 61.

[0104] 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 determines 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 "V1" and the number of teeth of the planetary gear 3 is "V2", the reduction ratio R1 is expressed by the following formula 1.

[0105] R1=V2 / (V1-V2)…(Formula 1) 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, when the eccentric shaft 7 rotates clockwise around the rotating shaft Ax1 for one full revolution (360 degrees), the inner ring 61 rotates counterclockwise around the rotating shaft Ax1 by the amount of the difference in the number of teeth "1" (approximately 7.06 degrees).

[0106] By using the gear device 1 involved in this basic structure, such a high reduction ratio R1 can be achieved through the combination of a first-stage gear (internal gear 2 and planetary gear 3).

[0107] 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. For example, it may also include spline sleeves as constituent elements.

[0108] However, as with the gear device 1 involved in this basic structure, when the input rotation, which is on the high-speed rotating side, is accompanied by eccentric motion, failure to achieve weight balance of the high-speed rotating body may lead to vibration, etc. Therefore, sometimes a counterweight or the like is 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, by providing a gap 75 in a portion of the eccentric part 72 of the eccentric shaft 7, the weight balance of the rotating body relative to the rotation shaft Ax1 is achieved.

[0109] In summary, in this basic structure, instead of adding counterweights, weight reduction is achieved by reducing the weight of a portion of the rotating body (here, the eccentric shaft 7), thereby achieving weight balance of the rotating body relative to the rotation axis Ax1. That is, the gear assembly 1 involved in this basic structure includes an eccentric bearing 5, which is housed in the opening 33 formed in the planetary gear 3 and causes 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. Viewed from the rotation axis Ax1 of the inner eccentric ring 51, 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 its center C1 side. 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, when viewed from the rotation axis Ax1, the gap 75 is located on the side of the center C1, so 75 functions to make the weight balance of the eccentric shaft 7 nearly equal in the circumferential direction from the rotation axis Ax1.

[0110] More specifically, the gap 75 includes a recess formed on the inner circumferential surface of the through hole 73 of the rotating body, which passes through the rotation axis Ax1 of the inner ring 51 of the eccentric body. In other words, in this basic structure, since the rotating body is the eccentric shaft 7, the recess formed on the inner circumferential surface of the through hole 73, which passes through the eccentric shaft 7 along the rotation axis Ax1, functions as the gap 75. Thus, by using 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.

[0111] (3.2) The self-rotation structure of domestic sales Next, refer to Figure 9 The rotation structure of the inner pin 4 of the gear device 1 involved in this basic structure will be explained in more detail. Figure 9 yes Figure 3 A magnified view of region Z1.

[0112] First, as a premise, as described above, the multiple inner pins 4 are parts that connect the planetary gear 3 and the inner ring 61 of the bearing component 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.

[0113] Here, the diameter of the inner pin 4 is slightly smaller than the diameter of the inner pin hole 32, thus ensuring a gap between the inner pin 4 and the inner circumferential surface 321 of the inner pin hole 32. This allows the inner pin 4 to move within the inner pin hole 32, i.e., to move relative to the center of the inner pin hole 32. On the other hand, although the diameter of the retaining hole 611 is larger than or equal to the diameter of the inner pin 4, it is 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 relative to the center of the retaining hole 611 is prohibited. Thus, 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 is held relative to the inner ring 61 in a state where it cannot revolve within the retaining hole 611. Thus, the oscillation component of planetary gear 3, that is, the revolution component of planetary gear 3, is absorbed through the clearance engagement between the inner pin hole 32 and the inner pin 4, and the rotation (rotation component) of planetary gear 3 other than the oscillation component (revolution component) is transmitted to the inner ring 61 through multiple inner pins 4.

[0114] However, in this basic structure, the diameter of the inner pin 4 is slightly larger than that of the retaining hole 611. Therefore, when the inner pin 4 is inserted into the retaining hole 611, it is prohibited from revolving within the retaining hole 611, but it can rotate on its own axis within the retaining hole 611. That is, even when the inner pin 4 is inserted into the retaining hole 611, it will not be pressed into the retaining hole 611, and thus it can rotate on its own axis within the retaining hole 611. In this way, in the gear device 1 involved in this basic structure, multiple inner pins 4 are each held in a rotatable state within the inner ring 61, so that when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 itself can rotate on its own axis.

[0115] In summary, in this basic structure, the inner pin 4 is held relative to the planetary gear 3 in a state where it can both revolve and rotate within the inner pin hole 32, and is held relative to the inner ring 61 in a state where it can only rotate within the retaining hole 611. That is, the multiple inner pins 4, in their respective unrestricted rotational states (capable of rotation), can rotate (revolve) around the rotation axis Ax1, and can also 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 through the multiple inner pins 4, the inner pin 4 can simultaneously revolve and rotate within the inner pin hole 32 while rotating 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 rotatable state, 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 less likely to cause losses due to frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4.

[0116] Thus, in the structure involved in this basic structure, since it is 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, the inner roller can be omitted. Therefore, in this basic structure, a structure is adopted in which multiple inner pins 4 are in direct contact with the inner circumferential surface 321 of the inner pin hole 32. That is, in this basic structure, the inner pin 4 in the state without the inner roller is installed 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, the diameter of the inner pin hole 32 can be kept small, and thus the planetary gear 3 can be miniaturized (especially the diameter can be reduced), and the gear device 1 as a whole can also be miniaturized. If the size of the planetary gear 3 is set to be fixed, compared with the first related technology, for example, the number of inner pins 4 can be increased to make the rotation transmission smoother, and the inner pins 4 can be thickened to increase strength. Furthermore, the number of parts can be reduced to the amount corresponding to the inner roller, and the cost of the gear device 1 can also be reduced.

[0117] Furthermore, in the gear assembly 1 involved in this basic structure, at least a portion of each of the plurality of inner pins 4 is arranged axially in the same position as the bearing component 6. That is, as Figure 9 As shown, at least a portion of the inner pin 4 is positioned at the same location as the bearing component 6 in a direction parallel to the rotation axis Ax1. In other words, at least a portion of the inner pin 4 is located between the two end faces of the bearing component 6 in a direction parallel to the rotation axis Ax1. Further, at least a portion of each of the plurality of inner pins 4 is positioned inside the outer ring 62 of the bearing component 6. In this basic structure, the end of the inner pin 4 located on the output side of the rotation axis Ax1 is positioned at the same location as the bearing component 6 in a direction parallel to the rotation axis Ax1. In summary, the end of the inner pin 4 located on the output side of the rotation axis Ax1 is inserted into the retaining hole 611 formed in the inner ring 61 of the bearing component 6, thus at least this end is positioned at the same location as the bearing component 6 in the axial direction.

[0118] In this way, by arranging at least a portion of each of the multiple inner pins 4 in the same position as the bearing component 6 in the axial direction, the size of the gear device 1 in the direction parallel to the rotation axis Ax1 can be reduced. That is, compared with the structure in which the bearing component 6 and the inner pins 4 are arranged (opposite) in the axial direction of the bearing component 6, the gear device 1 with this basic structure can reduce the size of the gear device 1 in the direction parallel to the rotation axis Ax1, which can help to further miniaturize (thinnify) the gear device 1.

[0119] Here, the opening on the output side of the rotating shaft Ax1 in the retaining hole 611 is closed, for example, by an output shaft integrated with the inner ring 61. Thus, the inner pin 4 extends towards the output side of the rotating shaft Ax1 ( Figure 9 The movement of the right side is limited by the output shaft integrated with the inner ring 61.

[0120] Furthermore, in this basic structure, to ensure smooth rotation of the inner pin 4 relative to the inner ring 61, the following structure is adopted. That is, 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, the rotation of the inner pin 4 is made smooth. Specifically, in this basic structure, a lubricant retaining space 17 for injecting lubricant exists between the inner ring 61 and the outer ring 62; therefore, the smooth rotation of the inner pin 4 is achieved by utilizing the lubricant within the lubricant retaining space 17.

[0121] In this basic structure, such as Figure 9 As shown, the inner ring 61 has a plurality of retaining holes 611 for inserting a plurality of inner pins 4 and a plurality of connecting paths 64. The plurality of connecting paths 64 connect the lubricant retention 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 on the opposing surface of the inner ring 61 opposite to the outer ring 62 and between the inner circumferential surface of the retaining hole 611. In other words, the opening surface of the connecting path 64 on the lubricant retention space 17 side is positioned facing (opposing) the rolling element 63 of the bearing component 6. The lubricant retention space 17 and the retaining hole 611 are spatially connected via such a connecting path 64.

[0122] According to the above structure, since the lubricant holding space 17 and the holding hole 611 are connected 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 component 6 moves and the rolling element 63 rotates, the rolling element 63 acts as a pump, which can deliver the lubricant in the lubricant holding space 17 into 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 located facing (opposite) to the rolling element 63 of the bearing component 6, so that the rolling element 63 effectively acts 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.

[0123] (3.3) Support body Next, refer to Figure 10 The structure of the support body 8 of the gear device 1 involved in this basic structure will be described in more detail. Figure 10 yes Figure 3 The sectional view along line B1-B1. However, in Figure 10In the text, for parts other than support body 8, section lines are omitted even in cross-sections. Additionally, in... Figure 10 Only the internal gear 2 and the support body 8 are shown in the diagram; other parts (such as the inner pin 4) are omitted. Additionally, in... Figure 10 The inner circumferential surface 221 of the gear body 22 is omitted from the diagram.

[0124] First, as mentioned above, the support body 8 is a component that supports multiple inner pins 4. That is, by binding the multiple inner pins 4 together, the support body 8 distributes the load applied to the multiple inner pins 4 when the rotation (rotation component) of the planetary gear 3 is transmitted to the inner ring 61. Specifically, it has multiple support holes 82 for inserting the multiple inner pins 4. 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 multiple inner pins 4 in a state where each inner pin 4 can rotate. That is, the multiple inner pins 4 are held in the inner ring 61 of the bearing component 6 and the support body 8 respectively in a state where they can rotate relative to both the inner ring 61 of the bearing component 6 and the support body 8.

[0125] In this way, multiple inner pins 4 are positioned relative to the support body 8 in both the circumferential and radial directions. That is, by inserting the inner pins 4 into the support holes 82 of the support body 8, the movement of the inner pins 4 in all directions within a plane orthogonal to the rotation axis Ax1 is restricted. Therefore, the inner pins 4 are positioned in the support body 8 not only in the circumferential direction but also in the radial direction.

[0126] Here, the support body 8 has an annular shape with at least its outer peripheral surface 81 viewed as a perfect circle. Furthermore, the support body 8 is positioned by contacting its outer peripheral surface 81 with a plurality of pins 23 of 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 positioned 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 imaginary circle (addition 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. Therefore, with the support body 8 positioned by the plurality of pins 23, the center of the support body 8 is positioned to coincide with the center (rotation axis Ax1) of the internal gear 2. Thus, 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.

[0127] Furthermore, the multiple inner pins 4 transmit the rotation (rotation component) of the planetary gear 3 to the inner ring 61 by rotating (revolving) around the rotation axis Ax1. Therefore, the support body 8 supporting 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, since the support body 8 is centered by the multiple pins 23, the support body 8 rotates smoothly while its center remains on the rotation axis Ax1. Moreover, the support body 8 rotates while its outer circumferential surface 81 is in contact with the multiple pins 23, so as the support body 8 rotates, the multiple pins 23 rotate (rotate). Therefore, the support body 8 and the internal gear 2 together constitute a needle roller bearing and rotate smoothly.

[0128] In other words, the outer peripheral surface 81 of the support body 8 rotates relative to the gear body 22 together with the multiple inner pins 4 while in contact with the multiple pins 23. Therefore, if the gear body 22 of the internal gear 2 is regarded as the "outer ring" and the outer ring support body 8 is regarded 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, which can rotate smoothly.

[0129] Furthermore, since the support body 8 clamps multiple pins 23 between itself and the gear body 22, the support body 8 also functions as a "limiting element" to inhibit the movement of the pins 23 away from the inner circumferential surface 221 of the gear body 22. That is, the multiple pins 23 are clamped between the outer circumferential surface 81 of the support body 8 and the inner circumferential surface 221 of the gear body 22, thereby preventing the multiple pins 23 from floating off the inner circumferential surface 221 of the gear body 22. In summary, in this basic structure, the multiple pins 23 are restricted from moving away from the gear body 22 by contacting the outer circumferential surface 81 of the support body 8.

[0130] However, in this basic structure, such as Figure 9As shown, the support body 8 is located on the opposite side of the inner ring 61 of the bearing component 6, separated from the planetary gear 3. That is, the support body 8, the planetary gear 3, and the inner ring 61 are arranged side-by-side in a direction parallel to the rotation axis Ax1. In this basic structure, as an example, viewed from the planetary gear 3, the support body 8 is located on the input side of the rotation axis Ax1, and viewed from the planetary gear 3, the inner ring 61 is located on the output side of the rotation axis Ax1. Furthermore, the support body 8 and the inner ring 61 together support both ends of the inner pin 4 in the longitudinal direction (parallel to the rotation axis Ax1), and the central portion of the inner pin 4 in the longitudinal direction is inserted into the inner pin hole 32 of the planetary gear 3. In summary, the gear device 1 involved in this basic structure includes a bearing component 6, which has an outer ring 62 and an inner ring 61 disposed inside the outer ring 62, the inner ring 61 being 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.

[0131] With this structure, the support body 8 and the inner ring 61 support the two ends of the inner pin 4 along its length, thus preventing the inner pin 4 from tilting. In particular, it is also susceptible to bending forces (bending moment loads) applied to the multiple inner pins 4 relative to the rotation axis 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 rotation axis Ax1. Thus, the housing 10 restricts the support body 8 from reaching the input side of the rotation axis Ax1 (…). Figure 9 The movement of the inner pin 4 (to the left side) through the support hole 82 of the support body 8 and protruding from the support body 8 toward the input side of the rotating shaft Ax1. Figure 9 The movement of the left side is also restricted by the housing 10.

[0132] 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 end located on the input side 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 end located on the output side of the rotation axis Ax1). According to this structure, the support body 8 and the inner ring 61 are centered by the two ends of the pin 23 along its length, thus preventing the inner pin 4 from tilting. In particular, it is also susceptible to bending forces (bending moment loads) applied to the multiple inner pins 4 relative to the rotation axis Ax1.

[0133] Furthermore, the multiple pins 23 have a length exceeding the thickness of the support body 8. In other words, in the direction parallel to the rotation axis Ax1, the support body 8 is contained within the tooth line of the internal teeth 21. Therefore, the outer peripheral surface 81 of the support body 8 contacts the multiple pins 23 along its entire length in the tooth line direction of the internal teeth 21 (parallel to the rotation axis Ax1). Thus, undesirable conditions such as "unilateral wear" where the outer peripheral surface 81 of the support body 8 is partially worn are less likely to occur.

[0134] Furthermore, in this basic structure, the surface roughness of the outer peripheral surface 81 of the support 8 is smaller than that of the surface adjacent to the outer peripheral surface 81 of the support 8. That is, the surface roughness of the outer peripheral surface 81 is smaller compared to the two end faces of the support 8 in the axial (thickness direction). The "surface roughness" described in this embodiment refers to the degree of surface roughness of an object; the smaller the value, the less unevenness and smoother the surface. In this basic structure, as an example, the surface roughness is the arithmetic mean roughness (Ra). For example, through processes such as grinding, the surface roughness of the outer peripheral surface 81 is smaller than that of the surfaces other than the outer peripheral surface 81 of the support 8. In this structure, the rotation of the support 8 becomes smoother.

[0135] 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 multiple pins 23, but 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 expressed, for example, 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 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 with the rotation of the support body 8, wear powder and the like are difficult to generate, and the smooth rotation of the support body 8 can be maintained for a long time.

[0136] (4) Application examples Next, an application example of the gear device 1 and actuator 100 involved in this basic structure will be described.

[0137] The gear mechanism 1 and actuator 100 involved in this basic structure are applied, for example, to horizontal multi-joint robots, such as the so-called Selective Compliance Assembly Robot Arm (SCARA) type robot.

[0138] Furthermore, the application examples of the gear device 1 and actuator 100 involved in this basic structure are not limited to the horizontal articulated robot described above. For example, they can also be industrial robots other than horizontal articulated robots, or robots other than industrial robots. Among industrial robots other than horizontal articulated robots, examples include vertical articulated robots or parallel linkage robots. Among non-industrial robots, examples include household robots, nursing robots, or medical robots.

[0139] (First Implementation) <Summary> The internal meshing planetary gear device 1A of this embodiment (hereinafter also referred to as "gear device 1A") is as follows: Figures 11-17 As shown, the main differences between the gear assembly 1 and the basic structure are the structures around the inner pin 4 and the input shaft (eccentric shaft 7). Hereinafter, structures identical to the basic structure will be labeled with the same reference numerals, and descriptions will be omitted as appropriate.

[0140] Figure 11 This is a schematic cross-sectional view of gear assembly 1A. Figure 12 This is a schematic cross-sectional view of the gear assembly 1A after the bushing 70 (described later) has been removed. Figure 13 It is from the input side of the rotation axis Ax1 ( Figure 11 The side view obtained by observing the gear device 1A from the left side. Figure 11 Equivalent to Figure 13 Sectional view along line A1-A1, Figure 12 Equivalent to Figure 13 Sectional view along line B1-A1. Figure 14 From the output side of rotating shaft Ax1 ( Figure 11 The side view obtained by observing the gear assembly 1A from the right side. Figure 13 and Figure 14 In the diagram, enlarged views of the Z1-Z1 line profiles of each individual are shown within the leader box. Figure 15 In the context of Figure 12 The same sectional view (equivalent to) Figure 13 A rough cross-sectional view of the state of the covers 163 and 164 and oil seals 14 and 15 after they have been removed, as described later, in the B1-A1 line cross-sectional view. Figure 16 It is from the input side of the rotation axis Ax1 ( Figure 15 The side view obtained by observing the gear device 1A with the covers 163, 164 and oil seals 14, 15 removed (from the left side). Figure 17 From the output side of rotating shaft Ax1 ( Figure 15 (Right side view of the gear assembly 1A with the covers 163, 164 and oil seals 14, 15 removed)

[0141] The first major difference between the gear device 1A in this embodiment and the basic structure is that the structure supporting the multiple inner pins 4 (support structure 40) uses rolling bearings 41 and 42 to hold the two ends of the inner pins 4. That is, the gear device 1A includes multiple sets of rolling bearings 41 and 42 on both sides of the planetary gear 3 in a direction parallel to the rotation axis Ax1, respectively, to hold the multiple inner pins 4. The multiple inner pins 4 are held in their respective sets of rolling bearings 41 and 42 in a rotatable state. Here, the multiple inner pins 4, while being inserted into the 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 about the rotation axis Ax1.

[0142] Another major difference between the gear device 1A in this embodiment and the basic structure is that it employs a structure for improving the lubrication of the inner pin 4. Specifically, the gear device 1A includes a circulation path 170 (see...). Figure 21 The circulation path 170 includes the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, and the rolling elements 402 in the rolling bearings 41, 42 (see...). Figure 20 Raceway 404 (see) Figure 20 The gear assembly 1A circulates lubricant through the circulation path 170. In other words, in this embodiment, the lubrication condition of the inner pin 4 is improved by circulating lubricant through the circulation path 170.

[0143] Furthermore, the third major difference between the gear device 1A of this embodiment and the basic structure is that, at least when the bearing component 6A, the internal gear 2, and the planetary gear 3 are assembled, multiple inner pins 4 can be removed individually. That is, the gear device 1A includes an inner pin path Sp1 (see...). Figure 15 The inner pin path Sp1 is located on at least one side of the plurality of inner pins 4 in a direction parallel to the rotation axis Ax1. With the bearing component 6A, the internal gear 2, and the planetary gear 3 assembled, the plurality of inner pins 4 can be removed individually. Furthermore, when viewed from a direction parallel to the rotation axis Ax1, the plurality of inner pins 4 are disposed inside the inner ring 61 (of the bearing component 6A).

[0144] Furthermore, the rolling elements 402 of the rolling bearings 41 and 42 (see...) Figure 20 Similar to the inner pin 4, it is configured to be detachable at least when the bearing component 6A, the internal gear 2, and the planetary gear 3 are assembled. Specifically, the rolling elements 402 of the rolling bearings 41 and 42 can be detached from the outer ring 62 of the bearing component 6A toward the opposite side of the planetary gear 3 in a direction parallel to the rotation axis Ax1.

[0145] Furthermore, the fourth major difference between the gear device 1A of this embodiment and the basic structure is that the bushing 70 is provided with a fixing structure 701 for fixing the matching component relative to the eccentric shaft 7, which serves as the input shaft. In other words, the gear device 1A includes an input shaft (eccentric shaft 7) that causes the planetary gear 3 to oscillate eccentrically, and a bushing 70. The bushing 70 has the fixing structure 701 for fixing the matching component and is coupled to the input shaft (eccentric shaft 7) and rotates together with it.

[0146] In summary, the main difference between the gear device 1A of this embodiment and the basic structure lies in the new use of a structure around the inner pin 4, particularly the design related to the support structure 40 (rolling bearings 41, 42) of the inner pin 4, the design for improving the lubrication of the inner pin 4, and the design for allowing the inner pin 4 to be removed. Furthermore, another major difference between the gear device 1A and the basic structure is the new use of a structure around the input shaft (eccentric shaft 7), particularly the design related to the bushing 70. Here, the rolling bearings 41, 42 are fixed to the inner ring 61 of the bearing component 6A, and the inner pin 4 is held in place within the inner ring 61 of the bearing component 6A by means of the rolling bearings 41, 42. Therefore, in the gear device 1A of this embodiment, the fact that multiple inner pins 4 are held in a self-rotating state within the inner ring 61 is also the same as in the basic structure.

[0147] Other differences In the gear device 1A of this embodiment, apart from the main differences mentioned above (the structure around the inner pin 4 and the structure around the input shaft), there are several differences relative to the basic structure, as will be explained below.

[0148] As another first difference, the bearing component 6A of the gear device 1A in this embodiment includes a first bearing component 601A and a second bearing component 602A. The first bearing component 601A and the second bearing component 602A are each constructed of an angular contact ball bearing, having an inner ring 61, an outer ring 62, and a plurality of rolling elements 63. The inner ring 61 of both the first bearing component 601A and the second bearing component 602A is annular, and its outer circumferential surface, viewed from above, is a perfect circle centered on the rotation axis Ax1. Specifically, as... Figure 11 As shown, viewed from planetary gear 3, on the input side of rotating shaft Ax1 ( Figure 11 The first bearing component 601A is arranged on the left side of the planetary gear 3, and is located on the output side of the rotating shaft Ax1. Figure 11 The second bearing component 602A is configured on the right side. The bearing component 6A is configured to withstand any one of the following through the first bearing component 601A and the second bearing component 602A: radial load, thrust load (along the direction of the rotation axis Ax1), and bending force (bending moment load) relative to the rotation axis Ax1.

[0149] Here, the first bearing component 601A and the second bearing component 602A are arranged opposite to each other in the direction parallel to the rotation axis Ax1 relative to the planetary gear 3. That is, the bearing component 6A is a "combined angular contact ball bearing" that combines multiple (in this case, two) angular contact ball bearings. Here, as an example, the first bearing component 601A and the second bearing component 602A are "back-to-back combination type" that bear the load in the direction in which their respective inner rings 61 approach each other, i.e., the thrust direction (along the direction of the rotation axis Ax1). Furthermore, in the gear assembly 1A, the first bearing component 601A and the second bearing component 602A are combined in a state where the inner rings 61 are properly preloaded by fastening their respective inner rings 61 toward each other. In the embodiments of this disclosure, "preload" refers to a state in which internal stress is always applied by pre-applied pressure, which is called preload. In other words, in the gear device 1A of this embodiment, in each of the first bearing component 601A and the second bearing component 602A, the rolling element 63 is pressed against the outer ring 62 from the outside in a direction parallel to the rotation axis Ax1.

[0150] As another second difference, such as Figure 11 As shown, the gear device 1A of this embodiment includes a planetary carrier flange 18 and an output flange 19. The planetary carrier flange 18 and the output flange 19 are arranged on opposite sides of the planetary gear 3 in a direction parallel to the rotation axis Ax1, and pass through the planetary carrier bore 34 of the planetary gear 3 (see...). Figure 12 And they combine with each other. Specifically, such as Figure 11 As shown, viewed from planetary gear 3, on the input side of rotating shaft Ax1 ( Figure 11 The planetary carrier flange 18 is configured on the left side, and viewed from the planetary gear 3, it is located on the output side of the rotating shaft Ax1. Figure 11 The output flange 19 is located on the right side of the planetary carrier flange 18. The inner ring 61 of the bearing component 6A (each of the first bearing component 601A and the second bearing component 602A) is fixed relative to the planetary carrier flange 18 and the output flange 19. In this embodiment, as an example, the inner ring 61 of the first bearing component 601A is seamlessly integrated with the planetary carrier flange 18. Similarly, the inner ring 61 of the second bearing component 602A is seamlessly integrated with the output flange 19.

[0151] The output flange 19 has a plurality of (in one example, 6) planetary carrier pins 191 protruding from one surface of the output flange 19 toward the input side of the rotating shaft Ax1 (see... Figure 12 These multiple planetary carrier pins 191 pass through multiple (in one example, six) planetary carrier holes 34 formed in the planetary gear 3, and their tops are secured relative to the planetary carrier flange 18 by planetary carrier bolts 181 (see...). Figure 12The planetary carrier pin 191 is fixed in place. Here, the diameter of the planetary carrier pin 191 is slightly smaller than the diameter of the planetary carrier bore 34. A clearance is ensured between the planetary carrier pin 191 and the inner circumferential surface of the planetary carrier bore 34, allowing the planetary carrier pin 191 to move within the planetary carrier bore 34, i.e., to move relative to the center of the planetary carrier bore 34. Furthermore, the clearance between the planetary carrier pin 191 and the inner circumferential surface of the planetary carrier bore 34 is larger than the clearance between the inner pin 4 and the inner circumferential surface 321 of the inner pin bore 32. When the inner pin 4 revolves within the inner pin bore 32, the planetary carrier pin 191 does not contact the inner circumferential surface of the planetary carrier bore 34. Additionally, multiple flange bolt holes 192 for fixing the output flange 19 itself are formed on the surface of the output flange 19 opposite to the planetary carrier pin 191 (see [reference]). Figure 17 ).

[0152] Here, the two ends of the inner pin 4 are not directly held to the inner ring 61 of the bearing component 6A, but are held (by means of rolling bearings 41, 42) to the planetary carrier flange 18 and the output flange 19 integrated with the inner ring 61. That is, the multiple inner pins 4 are indirectly held to the inner ring 61 of the bearing component 6A by being held to the planetary carrier flange 18 and the output flange 19.

[0153] Thus, the gear assembly 1A is used to extract the rotation of the planetary gear 3, corresponding to its rotational component, as rotation of the planetary carrier flange 18 and output flange 19, which are integrated with the inner ring 61 of the bearing component 6A. In other words, 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, which is connected to the planetary gear 3 via multiple 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 planetary carrier flange 18 and output flange 19, which are integrated with the inner ring 61. In this embodiment, as an example, the gear assembly 1A is used with the outer ring 62 of the bearing component 6A fixed to the housing, which is a fixed component. That is, the planetary gear 3 is connected to the planetary carrier flange 18 and output flange 19, which are rotating components, via multiple inner pins 4, and the gear body 22 is fixed to the fixed component; therefore, the relative rotation between the planetary gear 3 and the internal gear 2 is extracted from the rotating components (planetary carrier flange 18 and output flange 19). In other words, in this embodiment, the rotational force of the planetary carrier flange 18 and the output flange 19 is taken out as an output when the plurality of inner pins 4 rotate relative to the gear body 22.

[0154] As a third difference, in this embodiment, the housing 10 and the gear body 22 of the internal gear 2 are seamlessly integrated. 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 component 6. In contrast, in this embodiment, the gear body 22, which serves as a fixing component, and the housing 10 are seamlessly and continuously arranged in a direction parallel to the rotation axis Ax1.

[0155] More specifically, the housing 10 is cylindrical, forming the outline of the gear assembly 1A. In this embodiment, the central axis of the cylindrical housing 10 is aligned with the rotation axis Ax1. That is, at least the outer peripheral surface of the housing 10, viewed from above (from the direction of the rotation axis Ax1), is a perfect circle centered on the rotation axis Ax1. The housing 10 is formed as a cylinder with openings at both ends in the direction of the rotation axis Ax1. Here, the gear body 22 of the internal gear 2 is seamlessly integrated with the housing 10, and the housing 10 and the gear body 22 are treated as a single part. Therefore, the inner peripheral surface of the housing 10 includes the inner peripheral surface 221 of the gear body 22. In addition, the outer ring 62 of the bearing component 6A is fixed to the housing 10. That is, on the inner peripheral surface of the housing 10, at the input side of the rotation axis Ax1 as viewed from the gear body 22 (… Figure 11 On the left side), the outer ring 62 of the first bearing component 601A is fixed by means of embedding. On the other hand, on the output side of the rotating shaft Ax1 viewed from the gear body 22 on the inner circumferential surface of the housing 10 ( Figure 11 (on the right side), the outer ring 62 of the second bearing component 602A is fixed by means of embedding.

[0156] Furthermore, the housing 10 is located on the input side of the rotating shaft Ax1 ( Figure 11 The left end face of the housing 10 is closed by the planetary carrier flange 18, and the housing 10 is located on the output side of the rotating shaft Ax1. Figure 11 The right-hand end face (of which) is blocked by the output flange 19. Therefore, as Figure 11 and Figure 12 As shown, the planetary gear 3, multiple inner pins 4, multiple pins 23, and eccentric bearing 5 are housed within the space enclosed by the housing 10, planetary carrier flange 18, and output flange 19. Here, oil seal 161 blocks the gap between the planetary carrier flange 18 and the housing 10, and oil seal 162 blocks the gap between the output flange 19 and the housing 10. The space sealed by multiple oil seals 14, 15, 161, and 162 constitutes the lubricant retention space 17 in the same manner as the basic structure (see [link to basic structure]). Figure 11 Multiple mounting holes 111 are formed on both ends of the housing 10 in a direction parallel to the rotation axis Ax1 for fixing the housing 10 itself.

[0157] As a fourth 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 arranged opposite each other in a direction parallel to the rotation axis Ax1 (separated by the support ring 8A). That is, the planetary gears 3 include a first planetary gear 301 and a second planetary gear 302 arranged in a direction parallel to the rotation axis Ax1.

[0158] The two planetary gears 3 (first planetary gear 301 and second planetary gear 302) are configured about the rotation axis Ax1 with a phase difference of 180 degrees. Figure 11 In the example, in the first planetary gear 301 and the second planetary gear 302, the input side of the rotating shaft Ax1 is located ( Figure 11 The center C1 of the first planetary gear 301 (on the left side) is offset (biased) relative to the rotation axis Ax1 upwards. 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 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, weight balance is thus achieved among the multiple planetary gears 3, therefore the clearance 75 of the eccentric shaft 7 is omitted (see...). Figure 3 ).

[0159] 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 are identical in shape. Moreover, an eccentric bearing 5 is housed in the opening 33 of the first planetary gear 301, fitted with the eccentric portion 72 centered on center C1. Similarly, an eccentric bearing 5 is housed in the opening 33 of the second planetary gear 302, fitted with the eccentric portion 72 centered on center C2. 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.

[0160] Figure 18 and Figure 19 The state of the first planetary gear 301 and the second planetary gear 302 at a certain moment is shown. Figure 18 yes Figure 11 The A1-A1 sectional view shows the first planetary gear 301. Figure 19 yes Figure 11 The sectional view along line B1-B1 shows the second planetary gear 302. However, in Figure 18 and Figure 19 The illustration of cage 54 is omitted, and even the shading is omitted in the cross-section. For example... Figure 18 and Figure 19As shown, in the first planetary gear 301 and the second planetary gear 302, their centers C1 and C2 are located at a position 180 degrees rotationally symmetrical with respect to the rotation axis Ax1. In this embodiment, the eccentricity ΔL1 and eccentricity ΔL2 are viewed from the rotation axis Ax1 in opposite directions, but their absolute values ​​are the same. According to the above structure, the first planetary gear 301 and the second planetary gear 302 rotate around the rotation axis Ax1 with a phase difference of 180 degrees about the rotation axis Ax1 (eccentric motion) by rotating the shaft center 71 around the rotation axis Ax1.

[0161] As another fifth difference, in this embodiment, such as Figure 11 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...). Figure 3 ) and eccentric outer circle 52 (see Figure 3 Therefore, the inner circumferential surface of the planetary gear 3 (opening 33) replaces the outer ring 52 of the eccentric shaft to become the rolling surface of the multiple rolling elements 53, and the outer circumferential surface of the eccentric portion 72 replaces the inner ring 51 of the eccentric shaft to become the rolling surface of the multiple rolling elements 53. In this embodiment, the eccentric bearing 5 has a cage (bearing cage) 54, and the multiple rolling elements 53 are 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. As a result, as the cage 54 rotates, the multiple rolling elements 53 held by the cage 54 move in the circumferential direction of the eccentric portion 72.

[0162] As another sixth difference, such as Figure 11 As shown, the gear device 1A of this embodiment includes a support ring 8A instead of a support body 8. The support ring 8A is disposed between the two planetary gears 3, the first planetary gear 301 and the second planetary gear 302. The support ring 8A has an annular shape with at least its outer circumferential surface being a perfect circle. Furthermore, the support ring 8A is positioned by contacting the outer circumferential surface with a plurality of pins 23 of 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 ring 8A is positioned by contacting the outer circumferential surface with the internal teeth 21. Here, the diameter of the outer circumferential surface of the support ring 8A is the same as the diameter of the imaginary circle (tooth 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 circumferential surface of the support ring 8A. Therefore, with the support ring 8A positioned by the plurality of pins 23, the center of the support ring 8A is positioned so as to coincide with the center (rotation axis Ax1) of the internal gear 2.

[0163] Here, the support ring 8A is held between the first planetary gear 301 and the second planetary gear 302, and rotates around the axis of rotation Ax1 as the planetary gear 3 rotates (rotates). At this time, the support ring 8A rotates while its outer circumferential surface is in contact with multiple pins 23. Therefore, as the support ring 8A rotates, the multiple pins 23 rotate (rotate). Thus, the support ring 8A and the internal gear 2 together constitute a needle roller bearing, which rotates smoothly. That is, if the gear body 22 of the internal gear 2 is regarded as the "outer ring" and the support ring 8A as the "inner ring", then the multiple pins 23 between the two function as "rolling elements (rollers)". In this way, the support ring 8A and the internal gear 2 (gear body 22 and multiple pins 23) together constitute a needle roller bearing, which can rotate smoothly. In addition, since the support ring 8A has multiple pins 23 sandwiched between it and the gear body 22, the support ring 8A also functions as a "limiting element" to inhibit the pins 23 from moving away from the inner circumferential surface 221 of the gear body 22.

[0164] As another seventh difference, such as Figure 11 As shown, the gear device 1A of this embodiment includes a spacer 55. The spacer 55 is disposed between the first bearing 91 and the second bearing 92, which are inner bearing components, and the eccentric bearing 5. Specifically, the spacer 55 is disposed between the first bearing 91 and the eccentric bearing 5 on the side of the first planetary gear 301, and between the second bearing 92 and the eccentric bearing 5 on the side of the second planetary gear 302. The spacer 55 has an annular shape with at least its inner circumferential surface being a perfect circle. The spacer 55 functions as a "pressing member" for the eccentric bearing 5, restricting the movement of the eccentric bearing 5 (especially the cage 54) in a direction parallel to the rotation axis Ax1.

[0165] Here, the spacer 55 maintains a clearance between itself and the outer rings of the first bearing 91 and the second bearing 92. Therefore, in the first bearing 91 and the second bearing 92, their outer rings do not contact the spacer 55; only their inner rings contact the spacer 55. On the other hand, the first bearing component 601A and the second bearing component 602A, as bearing components 6A, maintain a clearance with the planetary gear 3. Therefore, the first bearing component 601A and the second bearing component 602A do not contact the planetary gear 3.

[0166] As another eighth difference, the gear device 1A of this embodiment is configured such that, when the plurality of inner pins 4 are not rotating relative to the internal gear 2, a preload is applied to each inner pin 4 from the planetary gear 3. That is, in the gear device 1A, when the plurality of inner pins 4 are not rotating relative to the internal gear 2, the inner circumferential surface 321 of each of the plurality of inner pin holes 32 presses against each of the plurality of inner pins 4, thus applying a preload to each of the plurality of inner pins 4. Here, the gear device 1A uses support structures 40 (rolling bearings 41, 42) to support the plurality of inner pins 4 respectively, maintaining the state of applied preload. The support structures 40 support the plurality of inner pins 4 respectively in a manner that counteracts the torque generated in each of the plurality of inner pins 4 due to the preload.

[0167] According to this structure, in the gear device 1A of this embodiment, the inner pin 4 is always in contact with the planetary gear 3 at a portion of the inner circumferential surface 321 of the inner pin hole 32, making it difficult for the inner pin 4 to separate from the planetary gear 3. Therefore, when the gear device 1A is driven, the inner pin 4 revolves within the inner pin hole 32 while being pressed against the inner circumferential surface 321 of the inner pin hole 32. Normally, considering assembly tolerances, a gap is ensured between the inner circumferential surface of the inner pin hole and the inner pin when the gear device is not driven after assembly. However, the gear device 1A of this embodiment is configured to intentionally eliminate this gap. Therefore, according to the gear device 1A of this embodiment, at least the backlash caused by the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 can be reduced or eliminated, thereby making it easier to suppress angle transmission errors to a smaller extent. Especially in the gear device 1A with a high reduction ratio, even if the backlash is caused by a small gap, the error of the rotation of the output side (output flange 19) relative to the rotation of the input side (eccentric shaft 7), that is, the angular transmission error, becomes larger, so the effect of reducing or eliminating backlash is greater.

[0168] In addition to the aspects mentioned above, the number of teeth, reduction ratio, number of internal pin holes 32 and internal pins 4, and specific shapes and dimensions of each part of the internal gear 2 and planetary gear 3 are also appropriately different in this embodiment and the basic structure. For example, there are 18 internal pin holes 32 and internal pins 4 in the basic structure, while there are 6 internal pin holes 32 and internal pins 4 in this embodiment as an example.

[0169] <Structure of Domestic Sales> Next, refer to Figures 11-20 The structure around the inner pin 4 in the gear device 1A of this embodiment will be described in detail.

[0170] First, as a premise, in the gear device 1A of this embodiment, the inner pin 4 moves (revolves) within the inner pin hole 32 along with the eccentric movement of the planetary gear 3. The amount of movement of the inner pin 4 at this time is in a linear direction orthogonal to the rotation axis Ax1 (for example, ...). Figure 11The eccentricity ΔL1 (ΔL2) in the vertical direction is twice that of the internal pin 32. Ideally, the diameter Di of the internal pin 32, expressed as the diameter Di of the internal pin 4, is "Di = di + 2ΔL1". Therefore, the internal pin 4 is inserted into the internal pin hole 32 with sufficient space (clearance) between it and the inner circumferential surface 321. However, both the diameter Di of the internal pin 4 and the diameter Di of the internal pin hole 32 are difficult to achieve at their design values ​​(ideal values), resulting in subtle deviations within tolerance limits. For example, if the diameter Di of the internal pin 4 is smaller than the design value, the clearance between the inner circumferential surface 321 of the internal pin hole 32 and the internal pin 4 increases, causing backlash and increasing angular transmission error. Conversely, if the diameter Di of the internal pin 4 is larger than the design value, the clearance between the inner circumferential surface 321 of the internal pin hole 32 and the internal pin 4 decreases, increasing the torque (input torque) required to rotate the eccentric shaft 7 and increasing losses in the gear mechanism 1A.

[0171] In this embodiment, as described above, at least with the bearing component 6A, the internal gear 2, and the planetary gear 3 assembled, the plurality of inner pins 4 can be removed via the inner pin passage Sp1. That is, in the gear assembly 1A, the plurality of inner pins 4 can be removed individually without disassembling the bearing component 6A, the internal gear 2, and the planetary gear 3. Here, the inner pin passage Sp1 is located on at least one side of the plurality of inner pins in a direction parallel to the rotation axis Ax1; therefore, the inner pins 4 are removed via the inner pin passage Sp1 in a manner that allows them to move along a direction parallel to the rotation axis Ax1.

[0172] In other words, at least one side of the multiple inner pins 4 in the direction parallel to the rotating shaft Ax1 can be opened through the inner pin passage Sp1, so that the multiple inner pins 4 can be removed individually through this open part (inner pin passage Sp1). Furthermore, by removing the inner pins 4, replacement of the inner pins 4 is possible. That is, after removing the inner pin 4, by reassembling another inner pin 4 or maintaining the same inner pin 4 (grinding or cleaning, etc.), at least with the bearing component 6A, the internal gear 2, and the planetary gear 3 assembled, replacement of the inner pin 4 is possible. The reassembled inner pin 4 is also inserted through the inner pin passage Sp1 in the same way as when it was removed.

[0173] In summary, based on the above structure, in the gear device 1A of this embodiment, the inner pin 4 can be replaced without disassembling the bearing component 6A, the internal gear 2, and the planetary gear 3. Therefore, for example, if the diameter di of the inner pin 4 is smaller than the design value, by replacing it with an inner pin 4 with a larger diameter, the backlash caused by the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 can be reduced or eliminated, thereby making it easier to suppress the angle transmission error. Conversely, if the diameter di of the inner pin 4 is larger than the design value, by replacing it with an inner pin 4 with a smaller diameter, the input torque required to rotate the eccentric shaft 7 can be suppressed, thereby making it easier to suppress the loss of the gear device 1A. Especially in the gear device 1A with a high reduction ratio, even backlash caused by a small gap increases the error of the rotation of the output side (output flange 19) relative to the rotation of the input side (eccentric shaft 7), i.e., the angle transmission error, thus the effect of reducing or eliminating backlash is significant.

[0174] Furthermore, according to the structure of this embodiment, the angular transmission error during the start-up of the gear device 1A from a stopped state can be reduced, thus significantly improving the starting characteristics of the gear device 1A and greatly enhancing its responsiveness during start-up or rotation direction switching. As a result, in fields such as robotics where frequent stopping, starting, or rotation direction switching is required and where angular transmission error is critical, the gear device 1A can fully utilize its characteristics.

[0175] Furthermore, in this embodiment, the multiple inner pins 4 are each held in a rotatable state within the inner ring 61. However, each inner pin 4 is not strictly held directly within the inner ring 61, but is indirectly held within the inner ring 61 of the bearing component 6A by means of rolling bearings 41, 42, which are integrated with the planetary carrier flange 18 and the output flange 19. Thus, by employing a structure in which the inner pins 4 are held in a rotatable state, the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 is small. Even when the inner pin 4 is pressed against the inner circumferential surface 321 of the inner pin hole 32 and revolves within the inner pin hole 32, the inner pin 4 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 minimizing losses caused by frictional resistance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4.

[0176] Furthermore, viewed from a direction parallel to the rotation axis Ax1, a plurality of inner pins 4 are arranged inside the inner ring 61 (of the bearing component 6A). That is, the plurality of inner pins 4 are arranged inside the bearing component 6A (the first bearing component 601A and the second bearing component 602A). Thus, since a plurality of inner pins 4 are arranged inside the bearing component 6A, the inner pins 4 can be removed simply by ensuring an inner pin passage Sp1 inside the bearing component 6A. Specifically, the planetary carrier flange 18 and the output flange 19 inside the bearing component 6A have holes for inserting the plurality of inner pins 4, and the inner pin passage Sp1 can be achieved by opening at least one of these holes in a direction parallel to the rotation axis Ax1. According to this structure, the increase in the radial dimension (in a direction orthogonal to the rotation axis Ax1) of the gear device 1A can be suppressed.

[0177] Furthermore, in the gear device 1A of this embodiment, such as Figure 15 As shown, the inner pin path Sp1 is located on both sides of the multiple inner pins 4 in a direction parallel to the rotation axis Ax1. That is, when viewed from the multiple inner pins 4, the input side of the rotation axis Ax1 ( Figure 15 (left side) and the output side of rotating shaft Ax1 ( Figure 15 Both sides (right side) can be opened via the inner pin path Sp1. Therefore, multiple inner pins 4 can be removed from either the input side or the output side of the rotation axis Ax1. Alternatively, an existing inner pin 4 can be pushed from one side parallel to the rotation axis Ax1, while the inner pin 4 can be removed from the other side parallel to the rotation axis Ax1. Therefore, when replacing an inner pin 4, for example, by pushing an existing inner pin 4 with a new inner pin 4 from the input side of the rotation axis Ax1, it is possible to remove the existing inner pin 4 from the output side of the rotation axis Ax1 while simultaneously inserting a new inner pin 4.

[0178] Furthermore, in this embodiment, the inner pin path Sp1 is not always open, but is covered by covers 163 and 164 at least when the gear assembly 1A is used. Covers 163 and 164 are detachably mounted relative to, for example, the planetary carrier flange 18 and the output flange 19. Specifically, cover 163 is detachably mounted relative to the planetary carrier flange 18, covering the inner pin path Sp1 on the input side of the rotating shaft Ax1 when mounted on the planetary carrier flange 18. Cover 164 is detachably mounted relative to the output flange 19, covering the inner pin path Sp1 on the output side of the rotating shaft Ax1 when mounted on the output flange 19.

[0179] In summary, the gear device 1A of this embodiment also includes covers 163 and 164. Covers 163 and 164 are movable between a first position covering the inner pin path Sp1 and a second position exposing the inner pin path Sp1. In this embodiment, covers 163 and 164 are mounted on the planetary carrier flange 18 and the output flange 19. Figure 11 and Figure 12 The state is equivalent to the "first position", the state after being removed from the planetary carrier flange 18 and the output flange 19. Figure 15 The state of (the first position) is equivalent to the "second position". The covers 163 and 164 only need to be able to move between the first position and the second position, and do not necessarily need to be able to be removed from the planetary carrier flange 18 and the output flange 19.

[0180] Furthermore, covers 163 and 164 together cover the multiple inner pin paths Sp1 corresponding to the multiple inner pins 4 in the first position. That is, in this embodiment, as an example, since there are 6 inner pins 4, there are also 6 inner pin paths Sp1 on both the input and output sides of the rotating shaft Ax1. Cover 163 does not cover the 6 inner pin paths Sp1 on the input side of the rotating shaft Ax1 one by one, but covers them all at once. Similarly, cover 164 does not cover the 6 inner pin paths Sp1 on the output side of the rotating shaft Ax1 one by one, but covers them all at once. Therefore, when cover 163 is removed, as Figure 16 As shown, the six inner pins on the input side of the rotating shaft Ax1 are exposed via path Sp1. When the cover 164 is removed, as... Figure 17 As shown, the six inner pins on the output side of the rotating shaft Ax1 are exposed via path Sp1.

[0181] Specifically, covers 163 and 164 are both annular rings with outer and inner circumferential surfaces that are perfectly circular when viewed from above. Furthermore, covers 163 and 164 are positioned by contacting their outer circumferential surfaces with the planetary carrier flange 18 and the output flange 19. That is, the planetary carrier flange 18 and the output flange 19 each have recesses that open outwards in a direction parallel to the rotation axis Ax1. Covers 163 and 164 are mounted to the planetary carrier flange 18 and the output flange 19 by fitting into these recesses. Additionally, oil seals 14 and 15 are embedded inside covers 163 and 164. That is, covers 163 and 164 are combined with oil seals 14 and 15 such that their inner circumferential surfaces contact the outer circumferential surfaces of oil seals 14 and 15, respectively. Therefore, the position of oil seals 14 and 15, when viewed from a direction parallel to the rotation axis Ax1, is restricted by covers 163 and 164.

[0182] In this embodiment, as an example, such as Figure 13 and Figure 14 As shown, covers 163 and 164 are mounted on the planetary carrier flange 18 and the output flange 19 by multiple (in one example, six) mounting screws 160. That is, cover 163 is secured to the planetary carrier flange 18 by tightening the six mounting screws 160 into the threaded holes 183 of the planetary carrier flange 18 with the screws 160 (see [reference]). Figure 16The cover 164 is fixed to the planetary carrier flange 18. With the cover 164 embedded in the recess of the output flange 19, it is secured by six mounting screws 160 in the threaded holes 193 of the output flange 19 (see [link to documentation]). Figure 17 (This is used to fix the cover 163 and 164 to the output flange 19. The cover 163 and 164 are made of the same material as other parts, such as stainless steel, cast iron, carbon steel for mechanical construction, chromium molybdenum steel, phosphor bronze or aluminum bronze.)

[0183] like Figure 13 As shown, an opening 165 is formed in the cover 163. The openings 165 are located at positions corresponding to the planetary carrier bolts 181 when the cover 163 is mounted on the planetary carrier flange 18. In this embodiment, since there are six planetary carrier bolts 181, six openings 165 are also provided. The openings 165 function as clearance holes to avoid the heads of the planetary carrier bolts 181. Furthermore, as... Figure 14 As shown, an opening 166 is formed in the cover 164. The openings 166 are located at positions corresponding to the flange bolt holes 192 when the cover 164 is installed on the output flange 19. In this embodiment, since there are six flange bolt holes 192, there are also six openings 166. The openings 166 function as through holes that expose the flange bolt holes 192.

[0184] Thus, in this embodiment, the mounting screws 160 for mounting the cover 163 to the planetary carrier flange 18 are separate from the planetary carrier bolts 181 for fixing the planetary carrier flange 18 to the output flange 19. Therefore, while keeping the planetary carrier flange 18 fixed to the output flange 19 using the planetary carrier bolts 181, the cover 163 can be removed from the planetary carrier flange 18 by removing the mounting screws 160. However, this structure is not limited to; the planetary carrier bolts 181 used to fix the planetary carrier flange 18 to the output flange 19 can also be used for mounting the cover 163 to the planetary carrier flange 18. In this case, the mounting screws 160 are omitted, the planetary carrier flange 18 is fixed to the output flange 19 using the planetary carrier bolts 181, and the cover 163 is mounted to the planetary carrier flange 18.

[0185] Additionally, this embodiment includes a positioning structure for positioning the cover bodies 163, 164 and the inner ring 61 relative to each other. As an example, the positioning structure consists of a protrusion 167 (see...). Figure 15 ) and recesses 184, 194 (see Figure 16 and Figure 17Specifically, protrusions 167 are provided on the opposing surfaces of the cover bodies 163 and 164, which face the planetary carrier flange 18 and the output flange 19, respectively. Recesses 184 and 194 are provided on the opposing surfaces (i.e., the recessed bottom surfaces) of the planetary carrier flange 18 and the output flange 19, respectively, corresponding to the protrusions 167. The cover body 163 is combined with the planetary carrier flange 18 in such a way that the protrusions 167 are embedded in the recesses 184 of the planetary carrier flange 18, and is positioned relative to the inner ring 61 of the first bearing component 601A integrated with the planetary carrier flange 18. Similarly, the cover body 164 is combined with the output flange 19 in such a way that the protrusions 167 are embedded in the recesses 194 of the output flange 19, and is positioned relative to the inner ring 61 of the second bearing component 602A integrated with the output flange 19.

[0186] With this positioning structure, the relative positions of the covers 163 and 164 with respect to the inner ring 61 can be determined with high precision. That is, the positions of the covers 163 and 164 can be precisely defined when viewed from a direction parallel to the rotation axis Ax1. In this embodiment, the positions of the oil seals 14 and 15, particularly when viewed from a direction parallel to the rotation axis Ax1, are limited by the covers 163 and 164. Therefore, by improving the positional accuracy of the covers 163 and 164, misalignment of the oil seals 14 and 15 can be suppressed. As a result, leakage of lubricant from the lubricant retention space 17 sealed by the oil seals 14 and 15 is easily suppressed.

[0187] Furthermore, the relative positions of the covers 163 and 164 and the inner ring 61 in the rotational direction centered on the rotation axis Ax1 are preferably uniquely determined by the positioning structure. Thus, the covers 163 and 164 are combined with respect to the inner ring 61 of the bearing component 6A in a non-rotationally symmetrical, i.e., 360-degree rotationally symmetrical, configuration with respect to the rotation axis Ax1. In this embodiment, as an example, such as... Figure 16 As shown, viewed from the input side of the rotation axis Ax1, the recesses 184 of the planetary carrier flange 18 are provided in multiple (two in this case) positions that are not rotationally symmetric about the rotation axis Ax1. Similarly, as Figure 17 As shown, viewed from the output side of the rotation axis Ax1, the recess 194 of the output flange 19 has multiple (two in this case) recesses at non-rotationally symmetrical positions about the rotation axis Ax1. As a result, the relative positional accuracy of the covers 163, 164 relative to the inner ring 61 is further improved.

[0188] Furthermore, in this embodiment, at least a portion of the plurality of inner pins 4 are held by the inner ring 61 (of the bearing component 6A) at the same position as the bearing component 6A in a direction parallel to the rotation axis Ax1. That is, as... Figure 15As shown, multiple sets of rolling bearings 41 and 42, which serve as the support structure 40 for retaining (supporting) the inner pin 4, are located at least partially overlapping with the first bearing component 601A and the second bearing component 602A in a direction parallel to the rotation axis Ax1. That is, in a direction parallel to the rotation axis Ax1, at least a portion of the rolling bearing 41 is located at the same position as the first bearing component 601A, and at least a portion of the rolling bearing 42 is located at the same position as the second bearing component 602A. In particular, in this embodiment, the width dimensions (in the direction parallel to the rotation axis Ax1) of each of the first bearing component 601A and the second bearing component 602A are approximately the same as the width dimensions of each of the rolling bearings 41 and 42. Therefore, in a direction parallel to the rotation axis Ax1, the first bearing component 601A and the second bearing component 602A respectively fall approximately within the respective ranges of the rolling bearings 41 and 42. In other words, the first bearing component 601A and the second bearing component 602A are respectively arranged on the outer side of each rolling bearing 41 and 42.

[0189] Thus, in this embodiment, the space originally located inside the bearing component 6A (first bearing component 601A and second bearing component 602A) of the gear device 1A is used as the space for the support structure 40 of the inner pin 4. Therefore, the increase in the size of the gear device 1A in the direction parallel to the rotation axis Ax1 caused by the installation of the support structure 40 can be suppressed.

[0190] In this embodiment, in particular, the support structure 40 (rolling bearings 41, 42) is disposed outside the inner bearing components (first bearing 91 and second bearing 92) and inside the bearing component 6A (first bearing component 601A and second bearing component 602A). In other words, the rolling bearings 41, 42 are disposed using the space between the inner bearing components (first bearing 91 and second bearing 92) and the bearing component 6A (first bearing component 601A and second bearing component 602A). Therefore, it is also possible to suppress the increase in the radial dimension (in the direction orthogonal to the rotation axis Ax1) of the gear device 1A caused by the arrangement of the rolling bearings 41, 42.

[0191] Furthermore, the inner pin path Sp1 communicates with the lubricant holding space 17, which holds the lubricant. Specifically, the inner pin path Sp1 is connected to the lubricant holding space 17 through the insertion holes of the inner pin 4 in the planetary carrier flange 18 and the output flange 19. According to this structure, when replacing the inner pin 4, etc., lubricant can be replenished to the lubricant holding space 17 from the inner pin path Sp1.

[0192] However, in this embodiment, a pair of rolling bearings 41, 42 hold the two ends of the inner pin 4 along its length in a state where the inner pin 4 can rotate. Here, as... Figure 20As shown, each rolling bearing 41, 42 has a cage (bearing cage) 401 and a plurality of rolling elements 402. The outer ring 403 of each rolling bearing 41, 42 also serves as the planetary carrier flange 18 and the output flange 19. Specifically, the inner circumferential surface of the insertion hole for the inner pin 4 in the planetary carrier flange 18 and the output flange 19 functions as the outer ring 403 of each rolling bearing 41, 42. The outer ring 403 is a perfect circle when viewed from above, and the inner diameter of the outer ring 403 is larger than the diameter (outer diameter) of the inner pin 4, thus creating a gap between the outer ring 403 and the outer circumferential surface of the inner pin 4. The plurality of rolling elements 402 are arranged in the gap between the outer ring 403 and the inner pin 4. The plurality of rolling elements 402 are arranged in the circumferential direction of the outer ring 403. All of the plurality of rolling elements 402 are metal parts of the same shape and are evenly spaced throughout the entire circumferential region of the outer ring 403. The cage 401 holds a plurality of rolling elements 402 at equal intervals in the circumferential direction of the outer ring 403.

[0193] In this embodiment, as an example, each rolling bearing 41 and 42 is a needle roller bearing. That is, each rolling bearing 41 and 42 has cylindrical rollers as rolling elements 402. Moreover, the shafts of the cylindrical rolling elements 402 are all arranged parallel to the rotation axis Ax1. In this embodiment, each rolling bearing 41 and 42 does not have an inner ring, and the inner pin 4 functions as the inner ring. Therefore, by using each rolling bearing 41 and 42, the inner pin 4 rotates relative to the outer ring 403 through the rolling of multiple rolling elements 402, and each rolling bearing 41 and 42 can hold the inner pin 4 in a position to rotate.

[0194] According to this structure, the inner pin 4 can rotate, making it 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, thus eliminating the need for the inner roller. Therefore, in this embodiment, 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 small, thus enabling miniaturization (especially small diameter) of the planetary gear 3, and facilitating the overall miniaturization of the gear assembly 1A. Furthermore, each inner pin 4 is held by a pair of rolling bearings 41, 42. Therefore, when the inner pin 4 rotates, losses due to frictional resistance between the inner pin 4 and the planetary carrier flange 18 and the output flange 19 are less likely to occur.

[0195] On the other hand, the arrangement of the multiple sets of rolling bearings 41, 42, viewed from a direction parallel to the rotation axis Ax1, is basically the same as the arrangement of the multiple inner pins 4. That is, as... Figure 18 and Figure 19As shown, viewed from a direction parallel to the rotation axis Ax1, with an imaginary circle VC1 passing through the centers of multiple inner pins 4, multiple sets of rolling bearings 41, 42 are arranged on this imaginary circle VC1. In this embodiment, particularly as... Figure 20 As shown, viewed from a direction parallel to the rotation axis Ax1, multiple sets of rolling bearings 41 and 42 are arranged at equal intervals in the circumferential direction around the rotation axis Ax1. Figure 20 The configuration of rolling bearing 41 is shown, but the configuration of rolling bearing 42 is the same. Additionally, in... Figure 20 Even in cross-sections, section lines are appropriately omitted.

[0196] In other words, multiple sets of rolling bearings 41, 42 are arranged at equal intervals along the circumference of the imaginary circle VC1. That is, when viewed from a direction parallel to the rotation axis Ax1, the imaginary circle VC1 passes through the centers of each of the multiple rolling bearings 41 (or 42), and the distance between any two adjacent rolling bearings 41 (or 42) on the imaginary circle VC1 is equal among the multiple rolling bearings 41 (or 42). According to this arrangement, multiple inner pins 4 are held by the multiple sets of rolling bearings 41, 42, and when driven by the gear mechanism 1A, the force applied to the multiple inner pins 4 can be evenly distributed.

[0197] Furthermore, in this embodiment, such as Figure 20 As shown, viewed from a direction parallel to the rotation axis Ax1, the center of the imaginary circle VC1, passing through the centers of the multiple sets of rolling bearings 41 and 42, coincides with the rotation axis Ax1. In other words, the center of the imaginary circle VC1 is the same as the center of the gear body 22 of the internal gear 2 or the center of the pitch circle of the internal gear 21, and is located on the rotation axis Ax1. According to this structure, the center of the gear body 22 of the internal gear 2 and the multiple inner pins 4 relative to the rotation center of the internal gear 2 can be easily and accurately maintained on the rotation axis Ax1. As a result, the gear assembly 1A has the advantage of being less prone to vibrations caused by poor centering and reduced transmission efficiency.

[0198] Next, the force (preload) acting on the inner pins 4 when they are not rotating relative to the internal gear 2, i.e., when the gear assembly 1A is not driven, will be described in more detail. The two ends of each inner pin 4 are held by a pair of rolling bearings 41, 42. Each rolling bearing 41, 42 maintains a state in which the multiple rolling elements 402 are pressed against the outer circumferential surface of each inner pin 4. As a result, a "preload" is maintained on the inner pins 4 from each rolling bearing 41, 42.

[0199] The aforementioned preload is achieved by setting a negative clearance (minus clearance) between the inner pin 4 and the plurality of rolling elements 402. The "negative clearance" referred to in this disclosure is a so-called "interference fit," meaning that the two elements overlap (press) each other during the designed assembly. That is, when the inner pin 4 is assembled with the rolling bearings 41 and 42, by making this clearance less than zero, the plurality of rolling elements 402 are pressed against the inner pin 4, thus preventing a positive clearance from forming between the inner pin 4 and the plurality of rolling elements 402. As a result, in the combined state of the inner pin 4 and the rolling bearings 41 and 42, preload is applied to the inner pin 4 from the plurality of rolling elements 402.

[0200] In this embodiment, as an example, the difference between the inner diameter of the outer ring 403 and the body diameter of the inner pin 4 is less than twice the body diameter of the rolling element 402. This results in a negative clearance (interference) of 0 or more between the inner pin 4 and the rolling element 402. As an example, the fitting tolerance of the inner pin 4 relative to the rolling bearings 41 and 42 is preferably "k6" or more, and more preferably "p6". In summary, each of the multiple sets of rolling bearings 41 and 42 has multiple rolling elements 402. Preload is applied by pressing the multiple rolling elements 402 against the multiple inner pins 4.

[0201] In this embodiment, a negative clearance is uniformly set for all of the multiple (here, 6) inner pins 4 relative to the rolling bearings 41 and 42. Therefore, the inner pins 4 are preloaded from both the rolling bearings 41 and 42. However, this structure is not a necessary structure for the gear device 1A, and it is also possible not to apply inner pin preload to a portion of the inner pins 4.

[0202] Furthermore, in this embodiment, preload is applied to the inner pin 4 not only from the rolling bearings 41 and 42, but also from the planetary gear 3. That is, preload is applied to the inner pin 4 from the planetary gear 3 through the negative clearance (minus clearance) provided between the inner pin 4 and the inner circumferential surface 321 of the inner pin hole 32.

[0203] As explained above, by applying a "preload" to the inner pin 4, the clearance between the inner pin 4 and the rolling bearings 41, 42 or the planetary gear 3 can be reduced or eliminated, and the wobble of the inner pin 4 caused by this clearance can be suppressed. As a result, the gear device 1A of this embodiment can reduce or eliminate backlash caused by the clearance between the inner pin 4 and the rolling bearings 41, 42 or the planetary gear 3, and the angular transmission error can be suppressed to a smaller extent.

[0204] <Structure for improving the lubrication of internal pins> Next, refer to Figures 21-24 The structure for improving the lubrication state of the inner pin 4 in the gear device 1A of this embodiment will be described in detail.

[0205] As a premise, especially in structures that preload the inner pin 4 with a negative clearance as described above, poor lubrication is prone to occur, particularly at the preloaded portion of the inner pin 4. If poor lubrication occurs, friction arises between the rolling bearings 41 and 42 or between the inner pin 4 and the inner circumferential surface 321 of the inner pin hole 32 when the inner pin 4 rotates. This friction can become a loss in power transmission. Furthermore, in the case of long-term use of the gear device 1A, for example, due to lubricant deterioration, the losses caused by friction increase, which may also hinder the longevity of the gear device 1A. Therefore, in the gear device 1A of this embodiment, by employing a structure for improving the lubrication state of the inner pin 4, a gear device 1A that easily reduces the losses generated when the inner pin 4 rotates is achieved.

[0206] like Figure 21 As shown, the gear device 1A of this embodiment includes a circulation path 170 as a structure for improving the lubrication state of the inner pin 4. This circulation path 170 includes the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, and the raceway 404 of the rolling elements 402 in the rolling bearings 41, 42. Furthermore, in the gear device 1A, the lubrication state of the inner pin 4 is improved by circulating lubricant in this circulation path 170. Figure 21 In the diagram, dashed arrows conceptually illustrate the flow (circulation) of lubricant in circulation path 170.

[0207] Here, the raceway 404 of the rolling element 402 in rolling bearings 41 and 42 refers to the path along which the rolling element 402 moves (rolls), and the gap between the outer ring 403 and the inner ring of each rolling bearing 41 and 42 corresponds to the raceway 404. In this embodiment, as described above, since the planetary carrier flange 18 or the output flange 19 also serves as the outer ring 403, and the inner pin 4 functions as the inner ring, the gap between the planetary carrier flange 18 or the output flange 19 and the inner pin 4 constitutes the raceway 404 of the rolling element 402. In other words, an annular raceway 404 is formed along the outer circumferential surface of the inner pin 4 centered on the central axis of the inner pin 4. Based on such a raceway 404, the path of the lubricant, including the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, corresponds to the circulation path 170.

[0208] In this embodiment, a circulation path 170 is formed within the lubricant holding space 17 for injecting lubricant. By forming such a circulation path 170, the lubricant circulates at least through the gap between the inner peripheral surface 321 of the inner pin hole 32 and the inner pin 4, as well as the raceway 404 of the rolling element 402, thus improving the lubrication condition of the inner pin 4. That is, although the structure applies pre-pressure to the inner pin 4 with a negative clearance as described above, by actively circulating the lubricant, a situation of "lubricant depletion" due to insufficient or exhausted lubricant is not easily generated around the inner pin 4, and a certain amount of lubricant is always supplied. Moreover, compared with a structure where the lubricant stagnates in a fixed position, by circulating the lubricant through the circulation path 170, the lubricant can be replaced at any time, even at the pre-pressured part of the inner pin 4, thereby suppressing the deterioration of the lubricant.

[0209] Therefore, even in the pre-loaded areas of the inner pin 4, lubrication is improved, reducing the likelihood of poor lubrication. When the inner pin 4 rotates, friction between the rolling bearings 41 and 42, or between the inner pin 4 and the inner circumferential surface 321 of the inner pin hole 32, is reduced. Thus, even with long-term use of the gear assembly 1A, losses due to friction are reduced, easily extending the service life of the gear assembly 1A. As a result, the gear assembly 1A of this embodiment has the advantage of easily reducing losses generated during the rotation of the inner pin 4. In summary, the gear assembly 1A of this embodiment is particularly less prone to reliability degradation during long-term use, thus improving the transmission efficiency of the gear assembly 1A, extending its service life, and enhancing its performance.

[0210] More specifically, in this embodiment, such as Figure 22 As shown, the lubricant is pushed out in a direction away from the planetary gear 3 in a direction parallel to the rotating shaft Ax1 by the contraction of the gap (between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4). Figure 22 This is an illustrative diagram schematically showing the flow of lubricant in the case of the third region R3, which is considered in the first region R1 to the fourth region R4.

[0211] In other words, if the planetary gear 3 is oscillated by rotating the eccentric shaft 7, the inner pin 4, while inserted into the inner pin hole 32 formed in the planetary gear 3, moves by revolving within the inner pin hole 32. Thus, as the inner pin 4 revolves within the inner pin hole 32, the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 repeatedly expands and contracts. That is, if viewed from the inner pin 4, the gap existing on the side of the rotation axis Ax1 (in...) Figure 22 The gap between the inner circumferential surface 321 of the inner pin hole 32 (located on the upper side) and the inner pin 4, then as the inner pin 4 revolves, this gap changes from... Figure 22 The state shown on the left is as follows Figure 22As shown on the right side, it contracts (compresses). Similarly, if we look at the opposite side of the rotation axis Ax1 when viewed from the inner pin 4 (in... Figure 22 The gap between the inner circumferential surface 321 of the inner pin hole 32 (located on the lower side) and the inner pin 4, then as the inner pin 4 revolves, this gap changes from... Figure 22 The state shown on the right is as follows Figure 22 As shown on the left, it contracts (compresses). This alternating process repeats with the revolution of the inner pin 4. Figure 22 The states shown on the left and right sides indicate that the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 repeatedly expands and contracts.

[0212] Furthermore, when the gap contracts, the lubricant that has entered the gap is pushed out of the gap in a direction parallel to the rotating shaft Ax1, moving away from the planetary gear 3. Thus, the inner pin 4, which revolves within the inner pin hole 32, constitutes a positive displacement pump like a vane pump, pushing the lubricant out of the gap with sufficient pressure, thereby facilitating the circulation of the lubricant in the circulation path 170. Figure 23 This is a schematic diagram illustrating the circulation of lubricant in the circulation path 170 by the pump function 172 generated by the revolution of the inner pin 4 within the inner pin hole 32. Thus, by having the pump function 172 in the circulation path 170, the lubricant circulates in the circulation path 170 at a certain flow rate, thereby improving the lubrication condition of the inner pin 4.

[0213] In particular, in this embodiment, such as Figure 22 As shown, when the eccentric shaft 7 rotates, the lubricant, moving away from the rotating shaft Ax1 due to centrifugal force, easily reaches the vicinity of the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4. In other words, in the high-reduction-ratio gear device 1A, because the eccentric shaft 7, which serves as the input shaft, rotates at high speed, a large centrifugal force acts on the lubricant from the eccentric shaft 7, and the lubricant easily reaches the inner pin 4 located around the eccentric shaft 7. Thus, the lubricant reaching the vicinity of the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 is pushed out by the pump function 172 as described above, thereby facilitating the circulation of the lubricant in the circulation path 170.

[0214] Furthermore, the gear device 1A of this embodiment includes a cover 163, 164 located on at least one side of the plurality of inner pins 4 in a direction parallel to the rotation axis. Here, as Figure 21 and Figure 22As shown, grooves 171 are formed in the covers 163 and 164, forming part of the circulation path 170. The grooves 171 are located on the opposing surfaces of the covers 163 and 164, opposite to the rolling bearings 41 and 42. The grooves 171 widen the gap between the covers 163 and 164 and the rolling bearings 41 and 42, ensuring a gap through which lubricant can pass. In this embodiment, as an example, the grooves 171 are located on the inner circumferential side of the covers 163 and 164, which are formed in annular shape. By forming such grooves 171, the circulation path 170 can be configured with a relatively simple structure.

[0215] Furthermore, in this embodiment, the groove 171 is formed to be continuous along the entire circumference of the covers 163 and 164. Therefore, when viewed from the input side of the rotation axis Ax1, the groove 171 is annular. By forming such a groove 171, the circulation path 170 connects between the plurality of inner pins 4. That is, the groove 171 is formed in an annular shape to connect the opposing portions of the covers 163 that face the plurality of (six in this embodiment) inner pins 4, so on the input side of the rotation axis Ax1, the circulation path 170 connects between the plurality of inner pins 4 through the groove 171. Similarly, since the groove 171 is formed in an annular shape to connect the opposing portions of the covers 164 that face the plurality of (six in this embodiment) inner pins 4, on the output side of the rotation axis Ax1, the circulation path 170 connects between the plurality of inner pins 4 through the groove 171. In this way, by forming a circulation path 170 connecting multiple inner pins 4, the lubricant can circulate over a wider range, thereby further improving the lubrication condition of the inner pins 4.

[0216] Furthermore, in this embodiment, the circulation path 170 causes the lubricant to circulate primarily in one direction. That is, as... Figures 21-23 As shown, the direction of the lubricant flowing in the circulation path 170 is fixed to one direction, and the lubricant flows in that one direction. The flow direction of the lubricant is determined, for example, by the direction of the centrifugal force acting on the lubricant when the eccentric shaft 7 rotates, as described above, and by the direction in which the lubricant is pushed out by the pump function 172 generated by the inner pin 4 revolving within the inner pin hole 32. In this embodiment, as an example, such as... Figure 21 As shown, in the first region R1, the lubricant circulates counterclockwise in the circulation path 170 containing the rolling bearing 41, and in the second region R2, the lubricant circulates counterclockwise in the circulation path 170 containing the rolling bearing 42. On the other hand, as... Figure 21As shown, in the third region R3, the lubricant circulates clockwise in the circulation path 170 containing the rolling bearing 41, and in the fourth region R4, the lubricant circulates counterclockwise in the circulation path 170 containing the rolling bearing 42. This makes the flow of lubricant within the circulation path 170 smoother, reducing the likelihood of lubricant stagnation, and thus further improving the lubrication condition of the inner pin 4.

[0217] Here, as Figure 23 As shown, at least a portion of the inner circumferential surface of the circulation path 170 is provided with a direction limiting part 173 that restricts the flow direction of the lubricant. That is, the circulation direction of the lubricant in the circulation path 170 is also... Figure 23 The direction limiting portion 173 is shown. The direction limiting portion 173 can be formed, for example, on at least a portion of the inner peripheral surface of the circulation path 170, such as the inner peripheral surface of the outer ring 403 or the surface of the groove 171 of the cover 163, 164, or it can be formed entirely on the inner peripheral surface of the circulation path 170. As an example, the direction limiting portion 173 is implemented by laser processing or the like to give at least a portion of the inner peripheral surface of the circulation path 170 a hydrodynamic directional control function. By providing such a direction limiting portion 173, the flow of lubricant within the circulation path 170 becomes smoother, and lubricant stagnation is less likely to occur, thus further improving the lubrication state of the inner pin 4.

[0218] In addition, in this embodiment, such as Figure 21 As shown, the cross-section including the rotation axis Ax1 is divided into a first block B1 that is on one side relative to the rotation axis Ax1 and a second block B2 that is on the other side. Furthermore, the first block B1 is divided into a first region R1 that is on one side relative to the planetary gear 3 and a second region R2 that is on the other side. The second block B2 is divided into a third region R3 that is on one side relative to the planetary gear 3 and a fourth region R4 that is on the other side. A circulation path 170 is provided in all the first regions R1, second regions R2, third regions R3, and fourth regions R4. In summary, as... Figure 21 The cross-section shown, including the rotating shaft Ax1, is divided into four regions: a first region R1 to a fourth region R4, by the rotating shaft Ax1 and the planetary gear 3. Figure 21 In the diagram, the first block B1, which includes the first region R1 and the second region R2, is located above the rotation axis Ax1, while the second block B2, which includes the third region R3 and the fourth region R4, is located below the rotation axis Ax1. Furthermore, the first region R1 and the third region R3 are located to the left of the planetary gear 3, and the second region R2 and the fourth region R4 are located to the right of the planetary gear 3.

[0219] By forming circulation paths 170 in all of the first regions R1 to the fourth region R4, the bias of circulation paths 170 in the gear assembly 1A can be suppressed. In other words, circulation paths 170 are distributed throughout the entire gear assembly 1A, thereby improving the lubrication condition of the inner pin 4 throughout the entire gear assembly 1A.

[0220] In this embodiment, the circulation path 170 circulates lubricant between the first region R1 and the third region R3, and between the second region R2 and the fourth region R4 (see [link]). Figure 28 In other words, in this embodiment, as described above, the groove 171 forming part of the circulation path 170 is formed to be continuous along the entire circumference of the covers 163 and 164, thereby connecting the circulation path 170 between the plurality of inner pins 4. As a result, lubricant circulates between the first region R1 and the third region R3 located on both sides of the rotating shaft Ax1, and similarly, between the second region R2 and the fourth region R4 located on both sides of the rotating shaft Ax1. Thus, the lubrication condition of the inner pins 4 can be improved throughout the entire gear assembly 1A.

[0221] In addition, such as Figure 24 As shown, at least one of the cover bodies 163, 164 and the inner pin 4 has a recess 174 that communicates with the circulation path 170 and retains lubricant. In this embodiment, as an example, the recess 174 is provided at the center of the opposing surface of the inner pin 4 opposite to the cover bodies 163, 164. The recess 174 widens the gap between the cover bodies 163, 164 and the inner pin 4, ensuring a gap between the cover bodies 163, 164 and the recess 174 that can retain lubricant. By retaining lubricant through this gap, lubricant can be supplied to the circulation path 170 even when the lubricant in the circulation path 170 decreases, thereby easily preventing the lubricant from running out.

[0222] <Structure around the input shaft> Next, the structure around the input shaft (eccentric shaft 7) in the gear device 1A of this embodiment will be described in detail.

[0223] In this embodiment, as described above, the gear device 1A includes a bushing 70 that engages with and rotates with an input shaft (eccentric shaft 7) that causes the planetary gear 3 to oscillate eccentrically. The bushing 70 has a fixing structure 701 for fixing the mating components.

[0224] According to the above structure, in the gear device 1A of this embodiment, the matching component is not directly fixed to the input shaft such as the eccentric shaft 7, but is fixed via a bushing 70 that engages with the input shaft. Therefore, compared to the case where the matching component is directly fixed to the end face of the input shaft, the outer diameter of the input shaft (the central portion 71 of the eccentric shaft 7) can be reduced. As a result, a gear device 1A that is easily miniaturized can be provided. Especially in gear devices 1A with high reduction ratios, the rotation from the matching component to the input shaft is sometimes at high speed, requiring a relatively strong connection between the input shaft and the matching component. According to the structure of this embodiment, since the matching component is fixed to the fixing structure 701 of the bushing 70, it can be more firmly connected to the input shaft without increasing the outer diameter of the input shaft.

[0225] Specifically, the bushing 70 has a cylindrical shape with at least its inner circumferential surface viewed as a perfect circle. The center (central axis) of the bushing 70 coincides with the rotation axis Ax1. The end of the bushing 70 located on the output side of the rotation axis Ax1 forms an insertion port 702 with an enlarged inner diameter (see...). Figure 12 The inner diameter of the insertion port 702 is approximately the same as the outer diameter of the central portion 71 of the eccentric shaft 7. Therefore, by inserting the end of the central portion 71 of the eccentric shaft 7 located on the input side of the rotating shaft Ax1 into the insertion port 702, the bushing 70 can be coupled to the eccentric shaft 7. In other words, in this embodiment, the bushing 70 has the insertion port 702 and is coupled to the input shaft when a portion of the input shaft (eccentric shaft 7) is inserted into the insertion port 702. The bushing 70 is made of the same material as the other parts, such as stainless steel, cast iron, carbon steel for mechanical construction, chromium-molybdenum steel, phosphor bronze, or aluminum bronze.

[0226] Furthermore, with a portion of the eccentric shaft 7 inserted (embedded) in the insertion port 702, the bushing 70 is pressed into place to engage with the eccentric shaft 7. Furthermore, the bushing 70 is bonded to the input shaft at least by adhesive. Specifically, the bushing 70 is firmly bonded to the eccentric shaft 7 by an adhesive applied to the inner circumferential surface of the insertion port 702. In summary, in this embodiment, the bushing 70 is bonded to the input shaft (eccentric shaft 7) by both pressing and adhesive. Thus, a strong bond is achieved between the bushing 70 and the eccentric shaft 7.

[0227] Furthermore, the outer diameter of the bushing 70 is at least larger than the outer diameter of the central portion 71 of the eccentric shaft 7. Therefore, when the bushing 70 is engaged with the eccentric shaft 7, the bushing 70 protrudes in a flange-like shape at the end of the eccentric shaft 7 located on the input side of the rotating shaft Ax1. Here, viewed from the perspective of the first bearing 91, which is an inner bearing component, the bushing 70 is located on the input side of the rotating shaft Ax1. Thus, the first bearing 91, as an inner bearing component, is positioned in a direction parallel to the rotating shaft Ax1, held between the eccentric portion 72 and the bushing 70. Therefore, the bushing 70 functions as a "pressing member" of the first bearing 91 and restricts the movement of the inner bearing component (first bearing 91) in the direction parallel to the rotating shaft Ax1. In summary, the gear device 1A of this embodiment includes an inner bearing component (first bearing 91) that holds the input shaft (eccentric shaft 7) so that it can rotate (indirectly) relative to the inner ring 61. Bushing 70 restricts the inner bearing component (first bearing 91) from moving to one side in a direction parallel to the rotation axis Ax1.

[0228] Furthermore, in this embodiment, the input shaft (eccentric shaft 7) and the bushing 70 have a through hole 73 extending along the rotation axis Ax1. That is, the through hole 73 extends from the axial center portion 71 of the eccentric shaft 7 to the bushing 70 along the rotation axis Ax1. Here, a fixing structure 701 for fixing the mating component is provided in the bushing 70. Therefore, if the outer diameter of the eccentric shaft 7 is the same, it is easier to ensure a larger diameter for the through hole 73 compared to the case without the bushing 70. In other words, since there is no need to provide a fixing structure on the eccentric shaft 7 itself, the eccentric shaft 7 (axial center portion 71) can be made thin-walled, and as a result, it is easier to increase the size of the through hole 73.

[0229] In this embodiment, as an example, the fixing structure 701 is constituted by a threaded hole. That is, by threading the mating component relative to the threaded hole serving as the fixing structure 701, the mating component can be fixed relative to the bushing 70. Here, the fixing structure 701 (threaded hole) is provided on the end face of the bushing 70 facing the input side of the rotation axis Ax1. Multiple threaded holes are provided as the fixing structure 701 (6 in this case) (see...). Figure 13 This device allows for the use of multiple screws to secure the object component. When using this fixing structure 701 to fix the mating component, the mating component is fixed relative to the bushing 70 on the input side of the rotation axis Ax1. In other words, the fixing structure 701 is configured to fix the mating component relative to the bushing 70 on one side in a direction parallel to the rotation axis Ax1.

[0230] Furthermore, in this embodiment, at least a portion of the fixing structure 701 is located at the same position as the input shaft in a direction parallel to the rotation axis Ax1. That is, as... Figure 15As shown, the fixing structure 701 for fixing the matching component is located at least partially overlapping the input shaft (eccentric shaft 7) in a direction parallel to the rotation axis Ax1. As a result, while the fixing structure 701 can be made larger, the increase in the size of the gear device 1A in the direction parallel to the rotation axis Ax1 can be suppressed.

[0231] Furthermore, in this embodiment, an inner pin path Sp1 is provided, which allows the inner pins 4 to be removed even when the bushing 70 is engaged with the eccentric shaft 7. In other words, the gear device 1A includes an inner pin path Sp1 located on at least one side of the plurality of inner pins 4 in a direction parallel to the rotation axis Ax1, allowing the plurality of inner pins 4 to be removed individually when the input shaft (eccentric shaft 7) and bushing 70 are combined. Therefore, in the gear device 1A, even after the bushing 70 is engaged with the input shaft (eccentric shaft 7), the plurality of inner pins 4 can be removed individually.

[0232] <Methods for replacing domestic sales, etc.> Next, refer to Figure 25 and Figure 26 This section describes the method for replacing the inner pin 4 and the rolling elements 402 of the rolling bearings 41 and 42 in the gear assembly 1A of this embodiment. Here, as an example, we will describe a situation in which the operator replaces the inner pin 4 and the rolling bearings 41 and 42, etc., during the manufacturing process of the gear assembly 1A for the purpose of adjusting the performance of the gear assembly 1A (backlash, input torque, etc.).

[0233] When replacing either the inner pin 4 or the rolling element 402, the operator will remove the mounting screw 160 and remove the covers 163, 164 and oil seals 14, 15 from the planetary carrier flange 18 and the output flange 19 (see [link]). Figure 15 By removing covers 163 and 164, the inner pin is exposed via path Sp1.

[0234] When replacing the domestic sales 4, such as Figure 25 As shown, the operator presses a new inner pin 4A, for example, into the planetary carrier flange 18 via path Sp1 from the inner pin on the input side of the rotating shaft Ax1. At this time, the existing inner pin 4, pushed by the new inner pin 4A, is pushed out towards the output side of the rotating shaft Ax1. Furthermore, with the new inner pin 4A fully inserted, the existing inner pin 4 is removed. In this method, since at least one of the new inner pin 4A and the existing inner pin 4 is always inserted in each rolling bearing 41, 42, the multiple rolling elements 402 of the rolling bearings 41, 42 are prevented from falling out by the inner pins 4, 4A.

[0235] Furthermore, in the above method, since the inner pins 4 can be replaced one by one, the gear device 1A can be experimentally driven each time an inner pin 4 is replaced to confirm its performance (backlash, input torque, etc.). Thus, it has advantages such as making it easy to identify inner pins 4 with defects and easily adjusting the performance of the gear device 1A to the desired level.

[0236] Additionally, when replacing rolling element 402, if Figure 26 As shown, the operator removes the existing rolling element 402, for example, from the inner pin path Sp1 on the output side of the rotating shaft Ax1. At this time, as an example, a clamp such as a magnet is appropriately used as the mechanism for removing the rolling element 402. Then, the operator inserts a new rolling element 402 from the inner pin path Sp1 on the output side of the rotating shaft Ax1.

[0237] Furthermore, in the above method, since the rolling elements 402 can be replaced one by one, the gear assembly 1A can be experimentally driven each time a rolling element 402 is replaced to confirm its performance (backlash, input torque, etc.). Therefore, it has advantages such as making it easy to identify rolling elements 402 with defects and easily adjusting the performance of the gear assembly 1A to the desired level.

[0238] When replacing either the inner pin 4 or the rolling element 402, the operator installs covers 163, 164 and oil seals 14, 15 onto the planetary carrier flange 18 and the output flange 19 after the replacement is completed. By installing covers 163, 164, the inner pin path Sp1 is blocked.

[0239] but, Figure 25 The illustrated method is only one example; the operator can also press a new inner pin 4A into the output flange 19 via path Sp1, for example, from the inner pin on the output side of the rotating shaft Ax1. Furthermore, when replacing the inner pin 4, the operator can also remove the inner pin 4 first and then replace it with a new inner pin 4A, just like with the rolling element 402. Alternatively, the inner pin 4 and the rolling element 402 can be replaced simultaneously.

[0240] Furthermore, the replacement of the inner pins 4 and rolling bearings 41, 42, etc., is not limited to the manufacturing process of the gear assembly 1A, but can also be performed during maintenance operations during the use of the gear assembly 1A. In other words, the maintenance method for the gear assembly 1A of this embodiment includes the following steps: with the bearing component 6A, the internal gear 2, and the planetary gear 3 assembled, at least one of the multiple inner pins 4 is replaced from at least one side in a direction parallel to the rotation axis Ax1. Additionally, the manufacturing method for the gear assembly 1A of this embodiment includes the step of inserting multiple inner pins 4 from at least one side in a direction parallel to the rotation axis Ax1 with the bearing component 6A, the internal gear 2, and the planetary gear 3 assembled.

[0241] <Application Example> like Figure 27 As shown, the gear device 1A of this embodiment, together with the first component 201 and the second component 202, constitutes a robot joint device 200. In other words, the robot joint device 200 of this embodiment includes the gear device 1A, the first component 201, and the second component 202. The first component 201 is fixed to the outer ring 62. The second component 202 is fixed to the inner ring 61. Figure 27 This is a schematic cross-sectional view of the robot's joint device 200.

[0242] In this embodiment, as an example, the first component 201 is indirectly fixed to the outer ring 62 of the bearing component 6A by fixing it relative to a plurality of mounting holes 111 formed in the housing 10. The second component 202 is indirectly fixed to the inner ring 61 of the bearing component 6A by fixing it relative to the planetary carrier flange 18.

[0243] The robot joint device 200 configured in this way functions as a joint device by rotating relative to the first component 201 and the second component 202 around the rotation axis Ax1. Here, the drive source 101 (see...) Figure 1 The first motor 203 drives the eccentric shaft 7 of the gear device 1A, causing the first component 201 and the second component 202 to rotate relative to each other. At this time, the rotation generated by the drive source 101 (input rotation) is reduced in the gear device 1A with a higher reduction ratio, driving the first component 201 or the second component 202 with a higher torque. That is, the first component 201 and the second component 202 connected by the gear device 1A can perform bending and stretching movements around the rotation axis Ax1.

[0244] More specifically, a first pulley P1 is fixed to the output shaft of the first motor 203. A second pulley P2 is connected to the first pulley P1 via a timing belt T1. Here, the second pulley P2 is fixed to the fixing structure 701 of the bushing 70 as a matching component. That is, when the first motor 203 is driven, its rotation is transmitted to the eccentric shaft 7, which serves as the input shaft, via the first pulley P1, the timing belt T1, and the second pulley P2.

[0245] Additionally, the robot articulation device 200 also includes a second motor 204. A third pulley P3 is fixed to the output shaft of the second motor 204. A fourth pulley P4 is connected to the third pulley P3 via a timing belt T2. Here, the fourth pulley P4 is fixed to a shaft 205. The shaft 205 passes through a through hole 73 through a bushing 70 and an eccentric shaft 7. A fifth pulley P5 is fixed to the end of the shaft 205 opposite to the fourth pulley P4. Thus, when the second motor 204 is driven, its rotation is transmitted to the fifth pulley P5 via the third pulley P3, the timing belt T2, the fourth pulley P4, and the shaft 205.

[0246] The robot joint device 200 is used, for example, in robots such as horizontal articulated robots (SCARA type robots). Furthermore, the robot joint device 200 is not limited to horizontal articulated robots; it can also be used in industrial robots or non-industrial robots, for example. Additionally, the gear device 1A of this embodiment is not limited to the robot joint device 200; it can also be used as a wheel device such as a hub motor in vehicles such as Automated Guided Vehicles (AGVs).

[0247] <Variation Example> The first embodiment is merely one of many embodiments of this disclosure. Various modifications can be made to the first embodiment based on design, etc., as long as the objectives of this disclosure are achieved. Furthermore, the accompanying drawings referenced in the embodiments of this disclosure are schematic diagrams, and the size and thickness ratios of the constituent elements in the drawings may not necessarily reflect the actual size ratios. Hereinafter, variations of the first embodiment are listed. The variations described below can be appropriately combined and applied.

[0248] In the first embodiment, two types of planetary gears 3 are illustrated in the gear assembly 1A, but the gear assembly 1A may also include three or more planetary gears 3. For example, when the gear assembly 1A includes three planetary gears 3, it is preferable that these three planetary gears 3 are arranged with a phase difference of 120 degrees around the rotation axis Ax1. Alternatively, the gear assembly 1A may include only one planetary gear 3. Or, when the gear assembly 1A includes three planetary gears 3, two of the three planetary gears 3 are in the same phase, and the remaining planetary gear 3 is arranged with a phase difference of 180 degrees around the rotation axis Ax1.

[0249] Furthermore, the inner pin path Sp1 only needs to be located on at least one side of the plurality of inner pins 4 in a direction parallel to the rotation axis Ax1, and does not need to be located on both sides. Additionally, covers 163 and 164 are not essential and can be omitted appropriately. Furthermore, covers 163 and 164 do not need to cover all the inner pin paths Sp1 corresponding to the plurality of inner pins 4 in the first position; covers 163 and 164 can be provided individually relative to each inner pin 4. Furthermore, the inner pin path Sp1 does not necessarily need to be in communication with the lubricant holding space 17; the inner pin path Sp1 can also be separated from the lubricant holding space 17.

[0250] Furthermore, the bushing 70 does not necessarily need to have an insertion port 702, and the insertion port 702 can be appropriately omitted. Also, the bushing 70 does not necessarily need to be bonded to the input shaft (eccentric shaft 7); for example, it can be bonded simply by pressing. Additionally, the bushing 70 restricting the movement of the inner bearing component (first bearing 91) to one side in the direction parallel to the rotation axis Ax1 is not a necessary structure. Furthermore, the through hole 73 of the input shaft (eccentric shaft 7) and the bushing 70 is not necessary. Furthermore, it is not necessary for the fixing structure 701 to be located at least partially in the same position as the input shaft in the direction parallel to the rotation axis Ax1.

[0251] Furthermore, when viewed from a direction parallel to the rotation axis Ax1, the multiple sets of rolling bearings 41 and 42 may not be arranged at equal intervals in the circumferential direction around the rotation axis Ax1. Moreover, when viewed from a direction parallel to the rotation axis Ax1, the center of the imaginary circle VC1 passing through the center of the multiple sets of rolling bearings 41 and 42 may not be consistent with the rotation axis Ax1.

[0252] Furthermore, the number of inner pins 4, the number of pins 23 (the number of teeth of the inner teeth 21), and the number of teeth of the outer teeth 31 described in the first embodiment are only examples and can be appropriately changed.

[0253] Furthermore, bearing component 6A is the same as the basic structure and can be a crossed roller bearing or a deep groove ball bearing, etc. However, it is preferable that bearing component 6A, such as a four-point contact ball bearing, can withstand any one of radial load, thrust load (along the direction of the rotation axis Ax1), and bending force (bending moment load) relative to the rotation axis Ax1.

[0254] In addition, the eccentric bearing 5 is not limited to roller bearings; for example, it can also be a deep groove ball bearing or an angular contact ball bearing.

[0255] Furthermore, the materials of the various components of the gear device 1A are not limited to metal; for example, they can also be resins such as engineering plastics.

[0256] Furthermore, the gear device 1A is only required to output the relative rotation between the inner ring 61 and the outer ring 62 of the bearing component 6, and is not limited to outputting the rotational force of the inner ring 61 (planetary carrier flange 18 and output flange 19). For example, the rotational force of the outer ring 62 (housing 10) that rotates relative to the inner ring 61 can also be output.

[0257] In addition, lubricants are not limited to liquid substances such as lubricating oil, but can also be gel-like substances such as lubricating grease.

[0258] Alternatively, the gear assembly 1A may also include internal rollers. That is, in the gear assembly 1A, the plurality of internal pins 4 do not necessarily have to be in direct contact with the inner circumferential surface 321 of the internal pin hole 32, and internal rollers may be sandwiched between each of the plurality of internal pins 4 and the internal pin hole 32. In this case, the internal rollers are assembled on the internal pins 4 and can rotate about the internal pins 4 as an axis.

[0259] In addition, the support ring 8A is not necessary in the gear device 1A, and the support ring 8A can be omitted appropriately. Alternatively, the support body 8 described in the basic structure can be used instead of the support ring 8A.

[0260] Furthermore, the gear assembly 1A only needs to employ at least one of the following designs: the support structure 40 (rolling bearings 41, 42) for the inner pin 4, the design for improving the lubrication of the inner pin 4, the design for disassembling the inner pin 4, and the design for the bushing 70; it is not necessary to employ all of them. That is to say, the gear assembly 1A may, for example, not employ the design for disassembling the inner pin 4 or the design for the bushing 70.

[0261] Furthermore, since the gear assembly 1A only needs to adopt a design to improve the lubrication of the inner pins 4, other structures can be appropriately omitted or modified from the basic structure. For example, the multiple inner pins 4 can also be arranged in different positions along the axial direction of the bearing component 6A than in the same position as the bearing component 6A.

[0262] Furthermore, the input shaft that engages with the bushing 70 can be any structure that causes the planetary gear 3 to oscillate eccentrically during rotation, and is not limited to a structure that integrally has a core portion 71 and an eccentric portion 72, such as the eccentric shaft 7. For example, the input shaft that engages with the bushing 70 may also be a core portion 71 that is separately formed from the eccentric portion 72. In this case, the eccentric portion 72 is installed relative to the input shaft (core portion 71) that engages with the bushing 70.

[0263] Furthermore, the positioning structure that positions the covers 163, 164 relative to the inner ring 61 is not limited to a structure that uniquely determines the relative positions of the covers 163, 164 and the inner ring 61 in the rotational direction centered on the rotation axis Ax1. For example, the positioning structure can also be used to position the covers 163, 164 rotationally symmetrically relative to the inner ring 61 of the bearing component 6A with the rotation axis Ax1 as the axis of symmetry. Moreover, the positioning structure is not limited to the protrusions 167 and the recesses 184, 194; for example, it can be achieved through the fitting tolerances of the covers 163, 164 relative to the planetary carrier flange 18 and the output flange 19. Additionally, the positioning structure is not essential and can be appropriately omitted.

[0264] In addition, the fixing structure 701 provided in the bushing 70 is not limited to a threaded hole, but may also be a double-ended bolt or an adhesive surface, etc.

[0265] Additionally, the covers 163 and 164 can be sealed to the planetary carrier flange 18 and the output flange 19, for example, by an O(O) ring. This improves the airtightness of the lubricant retention space 17.

[0266] In addition, the recess 174 can be formed in at least one of the cover body 163, 164 and the inner pin 4. It can be formed on the opposing surface of the cover body 163, 164 opposite to the inner pin 4, or it can be formed in both the cover body 163, 164 and the inner pin 4.

[0267] Furthermore, the circulation path 170 allows the lubricant to circulate between the first region R1 and the third region R3, but circulation between the second region R2 and the fourth region R4 is not a necessary structure. That is, as... Figure 28 As shown, unlike the gear device 1A of the first embodiment, a gear device 1B can also be configured such that the circulation path 170 between the first region R1 and the third region R3 is cut off, and the circulation path 170 between the second region R2 and the fourth region R4 is also cut off. In the modified gear device 1B, the circulation path 170 allows the lubricant to circulate separately in the first region R1, the second region R2, the third region R3, and the fourth region R4. According to this structure, the path length of the circulation path 170 for lubricant circulation can be shortened, thus enabling efficient lubricant circulation.

[0268] (Second Implementation) like Figure 29 As shown, the gear devices 1C and 1D of this embodiment differ from the gear device 1A of the first embodiment in that the circulation path 170 circulates the lubricant through the entire first region R1, second region R2, third region R3, and fourth region R4. Hereinafter, structures identical to those in the first embodiment will be labeled with the same reference numerals, and descriptions will be omitted as appropriate.

[0269] In other words, in the gear device 1A of the first embodiment, since the circulation path 170 between the first region R1 and the second region R2 is cut off, and the circulation path 170 between the third region R3 and the fourth region R4 is also cut off, the lubricant does not circulate through all the first region R1, the second region R2, the third region R3, and the fourth region R4. In contrast, in this embodiment, by connecting the circulation paths 170 of the first region R1, the second region R2, the third region R3, and the fourth region R4, the lubricant circulates through all the first region R1, the second region R2, the third region R3, and the fourth region R4.

[0270] exist Figure 29 The image shows two versions of the gear mechanism 1C and 1D according to this embodiment. Figure 29In the gear assembly 1C on the left, the circulation path 170 causes the lubricant to circulate sequentially through the first region R1, the second region R2, the fourth region R4, and the third region R3. That is, in... Figure 29 In the cross-section shown, the lubricant moves from the first region R1 to the second region R2, from the second region R2 to the fourth region R4, from the fourth region R4 to the third region R3, and from the third region R3 back to the first region R1, thus circulating clockwise among the four regions from the first region R1 to the fourth region R4. According to this structure, the lubricant circulates throughout the entire gear assembly 1C, thus potentially further improving the lubrication condition of the inner pin 4.

[0271] exist Figure 29 In the gear assembly 1D on the right side, the circulation path 170 causes the lubricant to circulate sequentially in the first region R1, the fourth region R4, the second region R2, and the third region R3. That is to say, in... Figure 29 In the cross-section shown, the lubricant moves from the first region R1 to the fourth region R4, from the fourth region R4 to the second region R2, from the second region R2 to the third region R3, and from the third region R3 back to the first region R1, thus circulating in the four regions from the first region R1 to the fourth region R4. According to this structure, the lubricant circulates throughout the entire gear assembly 1C, thus potentially further improving the lubrication condition of the inner pin 4.

[0272] The structure of the second embodiment can be appropriately combined with the various structures (including variations) described in the first embodiment.

[0273] (Summarize) As described above, the first type of internal meshing planetary gear assembly 1, 1A-1D includes bearing components 6, 6A, an internal gear 2, a planetary gear 3, multiple inner pins 4, multiple sets of rolling bearings 41, 42, and a circulation path 170. The bearing components 6, 6A have an outer ring 62 and an inner ring 61 disposed inside the outer ring 62, the inner ring 61 being supported so as to be able to rotate relative to the outer ring 62 about a rotation axis Ax1. 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 multiple inner pins 4, while being 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 multiple sets of rolling bearings 41, 42 respectively hold the multiple inner pins 4 on both sides of the planetary gear 3 in a direction parallel to the rotation axis Ax1. The circulation path 170 includes the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, and the raceway 404 of the rolling elements 402 in the rolling bearings 41, 42. In the internal meshing planetary gear assemblies 1, 1A-1D, lubricant is circulated through the circulation path 170.

[0274] According to this method, since the lubricant circulates at least through the gap between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4, as well as the raceway 404 of the rolling element 402, the lubrication condition of the inner pin 4 is improved. In other words, by actively circulating the lubricant, a situation of insufficient or depleted lubricant around the inner pin 4 is less likely to occur, ensuring a constant supply of a sufficient amount of lubricant. Furthermore, compared to a structure where the lubricant stagnates at a predetermined position, by circulating the lubricant through the circulation path 170, lubricant replacement can be performed at any time, thereby suppressing lubricant deterioration. As a result, it has the advantage of easily reducing losses generated during the rotation of the inner pin 4.

[0275] In the second type of internal meshing planetary gear device 1, 1A-1D, based on the first type, the lubricant is pushed out in the direction away from the planetary gear 3 in a direction parallel to the rotation axis Ax1 by the contraction of the gap.

[0276] According to this method, the lubricant is pushed out by the pump function, and the lubricant can easily circulate in the circulation path 170.

[0277] In the third-party internal meshing planetary gear device 1, 1A-1D, based on the first or second method, the circulation path 170 causes the lubricant to circulate mainly in one direction.

[0278] According to this method, the flow of lubricant in the circulation path 170 becomes smoother and less prone to lubricant stagnation, thus enabling further improvement in the lubrication condition of the inner pin 4.

[0279] In the fourth type of internal meshing planetary gear device 1, 1A-1D, based on the third type, a direction limiting part 173 that restricts the flow direction of the lubricant is provided on at least a portion of the inner peripheral surface of the circulation path 170.

[0280] According to this method, the flow of lubricant in the circulation path 170 becomes smooth, and lubricant stagnation is less likely to occur, thus enabling further improvement in the lubrication condition of the inner pin 4.

[0281] In the fifth type of internal meshing planetary gear device 1, 1A-1D, based on any of the first to fourth types, the circulation path 170 is connected between multiple inner pins 4.

[0282] According to this method, the lubricant can circulate over a wider range, which can further improve the lubrication condition of the inner pin 4.

[0283] The sixth type of internal meshing planetary gear assembly 1, 1A-1D, based on any of the first to fifth types, further includes an internal pin path Sp1. The internal pin path Sp1 is located on at least one side of the plurality of internal pins 4 in a direction parallel to the rotation axis Ax1, and the plurality of internal pins 4 can be removed individually when the bearing components 6, 6A, internal gear 2 and planetary gear 3 are combined.

[0284] According to this method, the inner pin 4 can be replaced without disassembling the bearing components 6, 6A, internal gear 2, and planetary gear 3. Therefore, for example, if the diameter of the inner pin 4 is smaller than the design value, by replacing it with an inner pin 4 with a larger diameter, the backlash caused by the clearance between the inner circumferential surface 321 of the inner pin hole 32 and the inner pin 4 can be reduced or eliminated, making it easier to suppress angular transmission errors. As a result, it is possible to provide internal meshing planetary gear devices 1, 1A-1D that easily suppress angular transmission errors.

[0285] In the seventh type of internal meshing planetary gear device 1, 1A-1D, based on any of the first to sixth types, the cross-section including the rotating shaft Ax1 is divided into a first block B1 on one side and a second block B2 on the other side relative to the rotating shaft Ax1. The first block B1 is further divided into a first region R1 on one side and a second region R2 on the other side relative to the planetary gear, and the second block B2 is further divided into a third region R3 on one side and a fourth region R4 on the other side relative to the planetary gear. A circulation path 170 is provided in all the first regions R1, second regions R2, third regions R3, and fourth regions R4.

[0286] According to this method, the circulation path 170 is distributed throughout the internal meshing planetary gear assembly 1, 1A-1D, and the lubrication condition of the inner pin 4 can be improved throughout the internal meshing planetary gear assembly 1, 1A-1D.

[0287] In the eighth type of internal meshing planetary gear device 1, 1A-1D, based on the seventh type, the circulation path 170 allows the lubricant to circulate separately in the first region R1, the second region R2, the third region R3 and the fourth region R4.

[0288] According to this method, the path length of the circulation path 170 for lubricant circulation can be shortened, thus enabling the lubricant to circulate effectively.

[0289] In the ninth type of internal meshing planetary gear device 1, 1A-1D, based on the seventh type, the circulation path 170 circulates the lubricant between the first region R1 and the third region R3, and between the second region R2 and the fourth region R4.

[0290] According to this method, the lubricant circulates between two regions separated by the rotating shaft Ax1 on the cross section containing the rotating shaft Ax1, thus potentially further improving the lubrication condition of the inner pin 4.

[0291] In the tenth type of internal meshing planetary gear device 1, 1A-1D, based on the seventh type, the circulation path 170 circulates the lubricant through all the first region R1, the second region R2, the third region R3 and the fourth region R4.

[0292] According to this method, since the lubricant circulates throughout the entire internal meshing planetary gear assembly 1, 1A-1D, it is expected to further improve the lubrication condition of the inner pin 4.

[0293] In the internal meshing planetary gear device 1, 1A-1D of the eleventh method, based on the tenth method, the circulation path 170 causes the lubricant to circulate sequentially in the first region R1, the second region R2, the fourth region R4, and the third region R3.

[0294] According to this method, since the lubricant circulates throughout the entire internal meshing planetary gear assembly 1, 1A-1D, it is expected to further improve the lubrication condition of the inner pin 4.

[0295] In the twelfth type of internal meshing planetary gear device 1, 1A-1D, based on the tenth type, the circulation path 170 causes the lubricant to circulate sequentially in the first region R1, the fourth region R4, the second region R2, and the third region R3.

[0296] According to this method, since the lubricant circulates throughout the entire internal meshing planetary gear assembly 1, 1A-1D, it is expected to further improve the lubrication condition of the inner pin 4.

[0297] The thirteenth type of internal meshing planetary gear device 1, 1A-1D, based on any of the first to twelfth types, further includes a cover 163, 164 located on at least one side of the plurality of inner pins 4 in a direction parallel to the rotation axis Ax1, wherein a groove 171 is formed in the cover 163, 164, and the groove 171 forms part of the circulation path 170.

[0298] Based on this, the loop path 170 can be set up with a relatively simple structure.

[0299] In the fourteenth type of internal meshing planetary gear device 1, 1A-1D, based on the thirteenth type, at least one of the cover 163, 164 and the inner pin 4 is provided with a recess 174 that communicates with the circulation path 170 and retains the lubricant.

[0300] According to this method, in cases where the lubricant in the circulation path 170 decreases, the lubricant held in the recess 174 can be supplied to the circulation path 170, thereby easily suppressing the occurrence of lubricant depletion.

[0301] The fifteenth type of robot joint device 200 includes an internal meshing planetary gear device 1, 1A-1D of any of the first to fourteenth types, a first component 201 fixed to the outer ring 62, and a second component 202 fixed to the inner ring 61.

[0302] According to this method, a robot joint device 200 can be provided that easily reduces the losses generated when the inner pin 4 rotates.

[0303] The structures of the second to fourteenth methods are not necessary for the internal meshing planetary gear devices 1, 1A-1D, and can be omitted appropriately.

[0304] Explanation of reference numerals in the attached figures: 1, 1A, 1B, 1C, 1D Internal meshing planetary gear system 2. Internal gears 3 Planetary gears 4. Domestic sales 6. 6A Bearing Components 21 Internal teeth 31 External teeth 32 Inner pin holes 41, 42 Rolling bearings 61 Inner Circle 62 Outer ring 163, 164 Cover 170 loop 171 Groove 173 Directional Restriction Section 174 recess 200 Robotic Joint Devices 201 First Component 202 Second Component 321 (Inner circumferential surface of the pin hole) 402 Rolling element 404 raceway Ax1 Rotation Axis B1 First Block B2 Second Block R1 First Area R2 Second Region R3 Third Region R4 Fourth Region Sp1 domestic sales path.

[0305] Industrial applicability According to embodiments of this disclosure, an internal meshing planetary gear device and a joint device for robots can be provided that easily reduce losses caused by the rotation of the inner pin.

Claims

1. An internal meshing planetary gear device, wherein, include: A bearing component having an outer ring and an inner ring disposed inside the outer ring, the inner ring being supported to be rotatable relative to the outer ring about a rotation axis; An internal gear having internal teeth and fixed to the outer ring; Planetary gears having external teeth that partially mesh with the internal teeth; Multiple inner pins, while being inserted into multiple inner pin holes formed in the planetary gear, revolve within the inner pin holes and rotate relative to the internal gear. Multiple sets of rolling bearings, with the multiple inner pins respectively held on both sides of the planetary gear in a direction parallel to the rotation axis; as well as The circulation path includes the gap between the inner circumferential surface of the inner pin hole and the inner pin, as well as the raceway of the rolling elements in the rolling bearing. In the internal meshing planetary gear assembly, the lubricant is circulated through the circulation path; The internal gear has an annular gear body and multiple pins, which are held on the inner circumferential surface of the gear body in a rotatable state to form the internal teeth. The gear assembly further includes a support body, the outer peripheral surface of which contacts the plurality of pins, and the support body supports the plurality of inner pins.

2. The internal meshing planetary gear device according to claim 1, wherein, The lubricant is pushed away from the planetary gear in a direction parallel to the rotation axis under the action of the contraction of the gap.

3. The internal meshing planetary gear device according to claim 1, wherein, The circulation path causes the lubricant to circulate primarily in one direction.

4. The internal meshing planetary gear device according to claim 3, wherein, At least a portion of the inner circumferential surface of the circulation path is provided with a directional limiting portion that restricts the flow direction of the lubricant.

5. The internal meshing planetary gear device according to claim 1, wherein, The circulation path is connected among the multiple internal pins.

6. The internal meshing planetary gear device according to claim 1, wherein, The internal meshing planetary gear assembly further includes an inner pin path, which is located on at least one side of the plurality of inner pins in a direction parallel to the rotation axis, allowing the plurality of inner pins to be removed individually when the bearing component, the internal gear, and the planetary gear are combined.

7. The internal meshing planetary gear device according to claim 1, wherein, The cross-section including the rotating shaft is divided into a first block on one side and a second block on the other side relative to the rotating shaft. The first block is further divided into a first region on one side and a second region on the other side relative to the planetary gear. The second block is divided into a third region on one side and a fourth region on the other side relative to the planetary gear. The loop path is provided in all of the first region, the second region, the third region, and the fourth region.

8. The internal meshing planetary gear device according to claim 7, wherein, The circulation path allows the lubricant to circulate separately in the first region, the second region, the third region, and the fourth region.

9. The internal meshing planetary gear device according to claim 7, wherein, The circulation path allows the lubricant to circulate between the first region and the third region, and between the second region and the fourth region.

10. The internal meshing planetary gear device according to claim 7, wherein, The circulation path allows the lubricant to circulate through all of the first, second, third, and fourth regions.

11. The internal meshing planetary gear device according to claim 10, wherein, The circulation path causes the lubricant to circulate sequentially in the first region, the second region, the fourth region, and the third region.

12. The internal meshing planetary gear device according to claim 10, wherein, The circulation path causes the lubricant to circulate sequentially in the first region, the fourth region, the second region, and the third region.

13. The internal meshing planetary gear device according to any one of claims 1 to 12, wherein, The internal meshing planetary gear assembly also includes a cover located on at least one side of the plurality of internal pins in a direction parallel to the axis of rotation. A groove is formed in the cover, which forms part of the circulation path.

14. The internal meshing planetary gear device according to claim 13, wherein, At least one of the cover and the inner pin has a recess that communicates with the circulation path and retains the lubricant.

15. A joint device for a robot, wherein, include: The internal meshing planetary gear device according to any one of claims 1 to 14; The first component is fixed to the outer ring; as well as The second component is fixed to the inner ring.

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