Internal gear planetary gear device, wheel device, and vehicle

Abstract

An internal meshing planetary gear device in which a structure is easily simplified. An internal tooth gear (2) has a ring-shaped gear body (22), and a plurality of pins (23) held in a self-rotating state to an inner peripheral surface of the gear body (22) and constituting internal teeth (21). A planetary gear (3) has external teeth (31) that partially mesh with the internal teeth (21). A plurality of internal pins (4) revolve in internal pin holes (32) formed in the planetary gear (3) and relatively rotate with respect to the gear body (22) in a state of being respectively inserted into the internal pin holes (32). A first bearing member (6) and a second bearing member (7) rotatably support the plurality of internal pins (4) to the gear body (22) at two portions in a rotational axis (Ax1) direction. The first bearing member (6) has a first inner ring (61), a first outer ring (62), and a plurality of bearing pins (63). The plurality of internal pins (4) are located inside the second bearing member (7) when viewed from one side in the rotational axis (Ax1) direction. A wheel device and a vehicle including the internal meshing planetary gear device are also disclosed.

Description

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Japanese Patent Application No. 2020-146351, filed on August 31, 2020, the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] As a linking technology, there is a known eccentric oscillating type gear device in which a planetary gear engages internally with an internal gear while eccentrically oscillating. In this gear device, the eccentric body is integrally formed with the input shaft, and the planetary gear is mounted on the eccentric body via an eccentric body bearing. External teeth, such as arc-shaped teeth, are formed on the outer periphery of the planetary gear.

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

[0006] In the aforementioned related technology structure, since crossed roller bearings are used as bearing components, there is a situation where the relatively complex structure of the crossed roller bearings hinders the simplification of the overall structure of the internal meshing planetary gear device.

[0007] The purpose of this disclosure is to provide an internal meshing planetary gear device, wheel device, and vehicle that are easy to simplify in structure.

[0008] An embodiment of the internal meshing planetary gear device disclosed herein includes an internal gear, a planetary gear, a plurality of inner pins, a first bearing member, and a second bearing member. The internal gear has an annular gear body and a plurality of pins that are rotatably held on the inner circumferential surface of the gear body and form internal teeth. The planetary gear has external teeth that partially mesh with the internal teeth. The plurality of inner pins, when respectively inserted into a plurality of inner pin holes formed in the planetary gear, revolve within the inner pin holes and rotate relative to the gear body. The first bearing member and the second bearing member rotatably support the plurality of inner pins on the gear body at two locations in the direction of rotation. The first bearing member has a first inner ring, a first outer ring, and a plurality of bearing pins. The plurality of inner pins, viewed from one side in the direction of rotation, are located inside the second bearing member.

[0009] One embodiment of the wheel assembly disclosed herein includes: the internal meshing planetary gear assembly; and a wheel body that rolls on a travel surface by rotational output when the plurality of inner pins rotate relative to the gear body.

[0010] One embodiment of the vehicle disclosed herein includes the wheel assembly and a body that holds the wheel assembly.

[0011] According to embodiments of this disclosure, it is possible to provide an internally meshing planetary gear assembly, a wheel assembly, and a vehicle with easily simplified structures. Attached Figure Description

[0012] Figure 1A The schematic structure of the internal meshing planetary gear device of Embodiment 1 is shown in a perspective view viewed from the output side of the rotating shaft.

[0013] Figure 1B The schematic structure of the aforementioned internal meshing planetary gear device is shown in a perspective view viewed from the input side of the rotating shaft.

[0014] Figure 2 This is a schematic exploded perspective view of the aforementioned internal meshing planetary gear device as seen from the output side of the rotating shaft.

[0015] Figure 3 This is a schematic cross-sectional view of the aforementioned internal meshing planetary gear assembly.

[0016] Figure 4 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 Sectional view along line A1-A1 and its enlarged portion.

[0017] Figure 5 This is a perspective view showing the structure around the internal gear and planetary gears of the aforementioned internal meshing planetary gear device.

[0018] Figure 6 This is an exploded perspective view showing the structure around the internal gear and planetary gear of the aforementioned internal meshing planetary gear device.

[0019] Figure 7 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 Sectional view along line B1-B1 and its enlarged portion.

[0020] Figure 8 This is a perspective view showing the structure around the first bearing component of the aforementioned internal meshing planetary gear device.

[0021] Figure 9 This is an exploded perspective view showing the structure around the first bearing component of the aforementioned internal meshing planetary gear device.

[0022] Figure 10 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 3 A magnified view of region Z1.

[0023] Figure 11 This is a schematic perspective view of a wheel assembly and vehicle that uses the aforementioned internal meshing planetary gear system.

[0024] Figure 12 This is a modified example of the internal meshing planetary gear device of embodiment 1, equivalent to Figure 10 Enlarged image.

[0025] Figure 13 This is a schematic cross-sectional view of the internal meshing planetary gear device of Embodiment 2.

[0026] Figure 14 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 13 Sectional view along line B1-B1 and its enlarged portion.

[0027] Figure 15 This is a modified example of the internal meshing planetary gear device of embodiment 2, equivalent to Figure 10 Enlarged image.

[0028] Figure 16 This is a schematic cross-sectional view of the internal meshing planetary gear device of Embodiment 3.

[0029] Figure 17 This illustrates the aforementioned internal meshing planetary gear mechanism. Figure 16 Sectional view along line B1-B1 and its enlarged portion. Detailed Implementation

[0030] (Implementation Method 1)

[0031] (1) Summary

[0032] The following is a summary of the internal meshing planetary gear device 1 of this embodiment, referring to... Figures 1A to 4 The accompanying drawings, which are used in the embodiments of this disclosure, are schematic diagrams, and the size and thickness ratios of the structural elements shown may not reflect the actual dimensional ratios. For example, Figures 1A to 4 The tooth shape, size, and number of teeth of the inner tooth 21 and the outer tooth 31 are merely schematic representations for illustrative purposes, and their main purpose is not limited to the shape shown in the illustration.

[0033] The internal meshing planetary gear device 1 (hereinafter, also simply referred to as "gear device 1") in this embodiment includes an internal gear 2 (see reference 1). Figure 4 A gear assembly consisting of a planetary gear 3 and multiple inner pins 4. In this gear assembly 1, a planetary gear 3 is arranged inside a ring-shaped internal gear 2, and an eccentric bearing 5 is arranged inside the planetary gear 3. The eccentric bearing 5 has an inner eccentric ring 51 and an outer eccentric ring 52. The inner eccentric ring 51 surrounds a ring extending from its center C1 (see reference 4). Figure 3 The offset rotation axis Ax1 (refer to) Figure 3 The planetary gear 3 oscillates due to the rotation (eccentric motion) of the eccentric inner ring 51, for example, by the rotation of the eccentric shaft 54 ​​inserted into the eccentric inner ring 51. Figure 4 The figure shows a rotation (eccentric motion) around the rotation axis Ax1.

[0034] The internal gear 2 has internal teeth 21. Specifically, in this embodiment, the internal gear 2 has an annular gear body 22 and multiple pins 23. The multiple pins 23 are held in a rotatable state on the inner circumferential surface 221 of the gear body 22, forming the internal teeth 21. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. That is, inside the internal gear 2, the planetary gear 3 is tangent to the internal gear 2, and a portion of the external teeth 31 meshes with a portion of the internal teeth 21. In this state, when the eccentric shaft 54 ​​rotates, the planetary gear 3 oscillates, and the meshing position of the internal teeth 21 and the external teeth 31 moves along 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) along with the relative rotation of the two gears. As a result, a rotational output that is reduced at a relatively high reduction ratio can be obtained from the planetary gear 3, corresponding to the difference in the number of teeth between the two gears.

[0035] This gear device 1 is used in such a way that the relative rotation between the planetary gear 3 and the internal gear 2, that is, the rotation of the planetary gear 3 with its rotational component when the internal gear 2 is fixed, is taken out, for example, as the relative rotation of the rotating member relative to the fixed member. In short, the gear device 1 rotates the rotating member by means of its output while the fixed member is fixed. Thus, the gear device 1 functions as a gear device with a relatively high reduction ratio, with the eccentric shaft 54 ​​as the input side and the rotating member as the output side. Therefore, in the gear device 1 of this embodiment, in order to transmit the relative rotation between the planetary gear 3 and the internal gear 2 to the fixed member and the rotating member, the gear body 22 is fixed to one of the fixed member and the rotating member, and the planetary gear 3 is connected to the other of the fixed member and the rotating member by a plurality of internal pins 4.

[0036] 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 internal gear 2. That is, the inner pin holes 32 have a larger diameter than the inner pins 4, allowing the inner pins 4 to move by revolving within the inner pin holes 32 when inserted. Furthermore, the oscillation component of the planetary gear 3, i.e., the revolution component of the planetary gear 3, is absorbed by the interlocking of the inner pin holes 32 and the inner pins 4. In other words, the multiple inner pins 4 move by revolving within the plurality of inner pin holes 32, thereby absorbing the oscillation component of the planetary gear 3. Therefore, through the multiple inner pins 4, the rotation (rotation component) of the planetary gear 3, excluding the oscillation component (revolution component), is transmitted to the fixed or rotating member.

[0037] In this way, the relative rotation between the planetary gear 3 and the internal gear 2 is transmitted to the fixed member and the rotating member as the relative rotation between the gear body 22 and the plurality of inner pins 4. Therefore, in the gear assembly 1, the reduced rotational output can be obtained from either the planetary gear 3 or the internal gear 2. That is, for example, when the gear body 22 is fixed to the fixed member, the planetary gear 3 is connected to the rotating member by the plurality of inner pins 4, so the relative rotation between the planetary gear 3 and the internal gear 2 is obtained from the planetary gear 3. On the other hand, when the gear body 22 is fixed to the rotating member, the planetary gear 3 is connected to the fixed member by the plurality of inner pins 4, so the relative rotation between the planetary gear 3 and the internal gear 2 is obtained from the internal gear 2.

[0038] Additionally, the gear assembly 1 includes a (first) bearing member 6. The bearing member 6 has a (first) inner ring 61 and a (first) outer ring 62. The inner ring 61 is disposed inside the outer ring 62 and is supported so as to be rotatable relative to the outer ring 62. The bearing member 6 is a component for rotatably supporting the rotating member to the fixed member. In other words, the (first) bearing member 6 is a component for rotatably supporting a plurality of inner pins 4 to the gear body 22. By supporting the rotating member to the fixed member in a rotatable state through such a bearing member 6, the gear assembly 1 can output the relative rotation between the planetary gear 3 and the internal gear 2 as the rotation of the rotating member relative to the fixed member.

[0039] However, in this gear assembly 1, as a related technology, the use of crossed roller bearings in the bearing components is known. In crossed roller bearings, the axis of the cylindrical rolling element (roller) is inclined at 45 degrees relative to a plane orthogonal to the rotation axis Ax1 and orthogonal to the outer circumference of the inner ring. Moreover, the axes of a pair of rolling elements adjacent to each other in the circumferential direction of the inner ring are orthogonal to each other. That is, in gear assembly 1, loads in various directions can act depending on its application, such as radial loads, thrust loads (loads in the direction along the rotation axis Ax1), and bending forces (bending moment loads) on the rotation axis Ax1. In related technologies, crossed roller bearings are used in the bearing components to withstand the aforementioned loads in various directions. However, in related technologies, since crossed roller bearings are used as bearing components, there is a situation where the relatively complex structure of the crossed roller bearing hinders the simplification of the overall structure of gear assembly 1. The gear assembly 1 of this embodiment provides an internal meshing planetary gear assembly 1 with a simplified structure that is easy to achieve through the following structure.

[0040] That is, as shown in Figure 1~ Figure 3 As shown, the gear device 1 of this embodiment includes an internal gear 2, a planetary gear 3, a plurality of inner pins 4, a first bearing member 6, and a second bearing member 7. The internal gear 2 has an annular gear body 22 and a plurality of pins 23 that are held in a rotatable state on the inner circumferential surface 221 of the gear body 22 and form internal teeth 21. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. The plurality of inner pins 4, when respectively inserted into a plurality of inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 and rotate relative to the gear body 22. The first bearing member 6 and the second bearing member 7 support the plurality of inner pins 4 at two locations in the direction of the rotation axis Ax1 so that they can rotate relative to the gear body 22. Here, the first bearing member 6 has a first inner ring 61, a first outer ring 62, and a plurality of bearing pins 63. Moreover, when viewed from one side in the direction of the rotation axis Ax1, the plurality of inner pins 4 are located inside the second bearing member 7.

[0041] According to this configuration, the first bearing member 6 and the second bearing member 7 support multiple inner pins 4 at two locations in the direction of rotation axis Ax1, allowing them to rotate relative to the gear body 22. Therefore, the multiple inner pins 4 are supported at two points on the gear body 22. Thus, compared to a single-point support where the multiple inner pins 4 are supported at one location in the direction of rotation axis Ax1, it is easier to withstand loads such as bending forces (bending moment loads) on the rotation axis Ax1. Furthermore, the first bearing member 6 has a first inner ring 61, a first outer ring 62, and multiple bearing pins 63. That is, the first bearing member 6 is a needle roller bearing that uses the bearing pins 63 as "rolling elements (rollers)," and can withstand relatively large radial loads. In addition, while being a two-point support, when viewed from one side in the direction of rotation axis Ax1, the second bearing member 7 is located outside the multiple inner pins 4, thus allowing for a simpler structure within the limited space inside the multiple inner pins 4. Therefore, compared with related technologies that use crossed roller bearings as bearing components, the gear device 1 of this embodiment has the advantage of being easy to simplify in structure.

[0042] Furthermore, crossed roller bearings are among the most expensive bearing components. Therefore, according to the structure of the gear device 1 of this embodiment, such crossed roller bearings can be omitted, thus also having the advantage of easy cost reduction.

[0043] (2) Definition

[0044] The term "annular" as used in this disclosure refers to a shape that forms a ring (circle) of enclosed space (area) on the inside, at least when viewed from above. It is not limited to a circular shape (annular) that is perfectly round when viewed from above; for example, it can also be an elliptical shape or a polygonal shape. Furthermore, even shapes with a bottom, such as a cup shape, are included in the term "annular" as long as their peripheral walls are annular.

[0045] The term "playing" in this embodiment refers to a state where the inner pin 4 is fitted with a clearance, and the inner pin hole 32 is a hole for the inner pin 4 to play. That is, the inner pin 4 is inserted into the inner pin hole 32 with sufficient space (clearance) between it and the inner circumferential surface 321 of the inner pin hole 32. In other words, the diameter of at least the portion of the inner pin 4 inserted into the inner pin hole 32 is smaller (thinner) than the diameter of the inner pin hole 32. Therefore, the inner pin 4, when inserted into the inner pin hole 32, can move within the inner pin hole 32, that is, it can move relative to the center of the inner pin hole 32. Thus, the inner pin 4 can revolve within the inner pin hole 32. However, it is not necessary to ensure a gap as a void between the inner circumferential surface of the inner pin hole 32 and the inner pin 4; for example, a fluid such as liquid can be filled into the gap.

[0046] In this embodiment of the disclosure, "revolution" refers to an object rotating around an axis other than the central axis passing through the object's center (center of gravity). When an object revolves, its center moves along a revolution path centered on the rotation axis. Therefore, for example, when an object rotates around an eccentric axis parallel to the central axis passing through its center (center of gravity), the object revolves around the eccentric axis. As an example, the inner pin 4 revolves around an axis of rotation passing through the center of the inner pin hole 32, and revolves within the inner pin hole 32.

[0047] Additionally, in this embodiment of the present disclosure, sometimes one side of the rotating shaft Ax1 ( Figure 3 The right side of the axis (Ax1) is called the "input side". The other side of the axis (Ax1) is called the "input side". Figure 3 The left side (of the output) is called the "output side". Figure 3 In the example, rotation is imparted to the rotating body (eccentric inner ring 51) from the "input side" of the rotating shaft Ax1, and the relative rotation between the planetary gear 3 and the internal gear 2 is taken out from the "output side" of the rotating shaft Ax1. However, "input side" and "output side" are merely labels given for illustrative purposes, and their purpose is not to limit the positional relationship between input and output as observed from the gear device 1.

[0048] In this embodiment of the disclosure, the "rotation axis" refers to a virtual axis (straight line) that serves as the center of rotational motion of the rotating body. That is, the rotation axis Ax1 is a virtual axis without a physical component. The inner ring 51 of the eccentric body rotates around the rotation axis Ax1.

[0049] In this embodiment of the disclosure, "internal teeth" and "external teeth" refer to a collection (group) of multiple "teeth" rather than a single "tooth". That is, the internal teeth 21 of the internal gear 2 are composed of a collection of multiple teeth 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.

[0050] (3) Structure

[0051] The following detailed structure of the internal meshing planetary gear device 1 according to this embodiment will be provided with reference to... Figures 1A to 10 Please provide an explanation.

[0052] Figure 1A The schematic structure of gear device 1 is shown, starting from the output side of rotating shaft Ax1 ( Figure 3 (The left side) Observe the three-dimensional view of the gear device 1. Figure 1B The schematic structure of gear device 1 is shown, starting from the input side of the rotating shaft Ax1 ( Figure 3 (The right side) Observe the three-dimensional view of the gear device 1. Figure 2This is a schematic 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 Sectional view along line A1-A1 and its enlarged portion. Figure 5 This is a perspective view primarily showing the structure surrounding the internal gear 2 and planetary gear 3 of the gear assembly 1. Figure 6 It is its exploded three-dimensional diagram. Figure 7 yes Figure 3 Sectional view along line B1-B1 and its enlarged portion. Figure 8 This is a perspective view primarily showing the structure surrounding the first bearing member 6 of the gear assembly 1. Figure 9 It is its exploded three-dimensional diagram. Figure 10 yes Figure 3 A magnified view of region Z1. Where, in Figure 4 and Figure 7 In the middle section, for components other than the eccentric shaft 54, although they are also cross-sections, the cross-section lines are omitted.

[0053] (3.1) Overall Structure

[0054] like Figures 1A to 3 As shown, the gear assembly 1 of this embodiment includes an internal gear 2, a planetary gear 3, multiple inner pins 4, an eccentric bearing 5, a first bearing member 6, a second bearing member 7, an eccentric shaft 54, and a support body 8. Furthermore, in this embodiment, the gear assembly 1 also includes a retaining member 55, a counterweight 56, a first bearing 91, a second bearing 92, a spacer 93, and a housing 10. In this embodiment, the materials of the internal gear 2, planetary gear 3, multiple inner pins 4, eccentric bearing 5, first bearing member 6, and second bearing member 7, which are components of the gear assembly 1, are stainless steel, cast iron, carbon steel for mechanical structures, chromium-molybdenum steel, phosphor bronze, or aluminum bronze. Furthermore, the materials of the eccentric shaft 54, support body 8, retaining member 55, counterweight 56, and housing 10 are also the same metals as described above. The metals mentioned here include metals that have undergone surface treatments such as nitriding.

[0055] Furthermore, in this embodiment, as an example of gear device 1, an internally tangent planetary gear device with a subcycloidal tooth profile is illustrated. That is, the gear device 1 of this embodiment includes an internally tangent planetary gear 3 having a subcycloidal curved tooth profile.

[0056] In addition, in this embodiment, as an example, the gear device 1 uses a retaining member 55 (see reference 4) to hold a plurality of inner pins 4. Figure 2It is used in a fixed state attached to a fixed member (such as the hub member 14 described later). That is, the planetary gear 3 is connected to the fixed member by a plurality of inner pins 4, and the gear body 22 is fixed to a rotating member (such as the main body 11 described later). Therefore, the relative rotation between the planetary gear 3 and the internal gear 2 is taken out from the internal gear 2. In other words, in this embodiment, when the plurality of inner pins 4 rotate relative to the gear body 22, the rotational force of the gear body 22 is taken out as the output.

[0057] Furthermore, in this embodiment, as an example, the gear device 1 is used in the wheel device W1 (see reference). Figure 11 Details will be described later. In this case, the rotating component (main body 11, etc.) serves as the wheel body 102 (see reference). Figure 11 The gear unit 1 functions such that, with the relative rotation of the internal gear 2 and the planetary gear 3, the wheel body 102 can be rotated. Thus, in this embodiment, by using the gear unit 1 in the wheel assembly W1, the wheel body 102 can be driven to roll on the travel surface by the rotational output of the multiple internal pins 4 relative to the gear body 22. In summary, when the gear unit 1 is used as the wheel assembly W1, it applies a rotational force as input to the eccentric shaft 54 ​​and extracts a rotational force as output from the rotating member (body part 11, etc.) that serves as the wheel body 102. That is, the gear unit 1 operates by rotating the eccentric shaft 54 ​​as input and rotating the rotating member (body part 11, etc.) to which the gear body 22 is fixed as output rotation. Therefore, in the gear unit 1, relative to the input rotation, an output rotation that is reduced at a relatively high reduction ratio can be obtained as the rotation of the wheel body 102.

[0058] Furthermore, in the gear device 1 of this embodiment, such as Figure 3 As shown, the input-side rotation axis Ax1 and the output-side rotation axis Ax1 are on the same straight line. In other words, the input-side rotation axis Ax1 and the output-side rotation axis Ax1 are coaxial. Here, the input-side rotation axis Ax1 is the rotation center of the eccentric shaft 54 ​​to which the input rotation is imparted, and the output-side rotation axis Ax1 is the rotation center of the gear body 22 to which the output rotation is generated. That is, in the gear device 1, an output rotation with a relatively high reduction ratio can be obtained by rotating coaxially relative to the input.

[0059] like Figure 1A and Figure 1BAs shown, the housing 10 is cylindrical and forms the outline of the gear device 1. In this embodiment, the housing 10 functions as the wheel body 102, therefore the central axis of the cylindrical housing 10 is configured to coincide with the rotation axis Ax1. That is, at least the outer peripheral surface of the housing 10, when viewed from above (viewed from the side in the direction of the rotation axis Ax1), is a perfect circle centered on the rotation axis Ax1.

[0060] The housing 10 has a main body 11, a cover 12, a ring cover 13, and a hub member 14. The main body 11 is a cylindrical component with openings at both ends in the direction of the rotation axis Ax1. The cover 12 is mounted on the output side of the rotation axis Ax1 of the main body 11. Figure 3 A disc-shaped component that closes the opening on the output side of the rotation shaft Ax1 of the main body 11 on the left end face. The ring cover 13 is located on the input side of the rotation shaft Ax1 of the main body 11. Figure 3 A ring-shaped component is mounted on the end face of the right side of the main body 11. The hub component 14 is a ring-shaped component disposed inside the ring cover 13. A portion of the opening face on the input side of the rotation shaft Ax1 of the main body 11 is filled by the hub component 14. Here, the main body 11, cover 12, ring cover 13 and hub component 14 are all formed into a perfect circle centered on the rotation shaft Ax1 when viewed from above.

[0061] Multiple (eight in one example) threaded holes 111 are formed on the end face of the output side of the rotating shaft Ax1 of the main body 11 (see reference). Figure 5 Multiple threaded holes 111 are used to secure the cover 12 to the main body 11. Specifically, multiple screws 151 for securing the cover 12 pass through the cover 12 and are screwed into the threaded holes 111, thereby securing the cover 12 to the main body 11. Multiple threaded holes 112 (eight in one example) are formed around the end face of the input side of the rotation shaft Ax1 of the main body 11 (see reference). Figure 8 Multiple threaded holes 112 are used to secure the ring cap 13 to the main body 11. Specifically, multiple screws 152 for securing the ring cap 13 are passed through the ring cap 13 and screwed into the threaded holes 112, thereby securing the ring cap 13 to the main body 11.

[0062] Furthermore, the internal space of the housing 10, which is enclosed by the main body 11, cover 12, ring cover 13, and hub member 14, houses the internal gear 2, planetary gear 3, multiple inner pins 4, eccentric bearing 5, first bearing member 6, second bearing member 7, and support body 8. The hub member 14 is mounted from the input side of the rotation shaft Ax1 to a retaining member 55 that holds the multiple inner pins 4. Multiple (eight in one example) threaded holes 554 are formed on the end face of the retaining member 55 on the input side of the rotation shaft Ax1 (see reference). Figure 9Multiple threaded holes 554 are used to secure the hub component 14 to the retaining member 55. Specifically, multiple screws 153 for securing the hub component 14 pass through the hub component 14 and are screwed into the threaded holes 554, thereby securing the hub component 14 to the retaining member 55.

[0063] Here, multiple (four in one example) fixing holes 141 are formed on the end face of the input side of the rotation shaft Ax1 of the hub member 14 (see reference). Figure 1B Multiple mounting holes 141 are used to secure the hub member 14. In this embodiment, since the gear device 1 is used for the wheel device W1, the hub member 14 is positioned relative to the vehicle body 100 on which the wheel device W1 is mounted (see reference 100). Figure 11 The wheel hub component 14 is fixed. Specifically, multiple screws (four in one example) for fixing pass through a part of the vehicle body 100 and are screwed into the fixing holes 141, thereby fixing the wheel hub component 14 relative to the vehicle body 100. In this way, the wheel hub component 14 is fixed to the vehicle body 100 even within the housing 10 that constitutes the wheel body 102, forming a "fixed component" that does not rotate even when the gear device 1 is driven. On the other hand, the main body 11, the cover 12, and the ring cover 13 constitute "rotating components" that rotate relative to the wheel hub component 14 when the gear device 1 is driven. That is, when the multiple inner pins 4 rotate relative to the gear body 22, the rotation of the rotating components (main body 11, cover 12, and ring cover 13) relative to the fixed component (wheel hub component 14) is taken out as an output of the gear device 1. When the housing 10 is used as the wheel body 102, these rotating components rotate and roll on the travel surface.

[0064] Therefore, the ring cover 13, which is a rotating member, and the hub member 14, which is a fixed member, are configured to rotate relative to each other about the rotation axis Ax1. Specifically, the outer diameter of the hub member 14 is smaller than the inner diameter of the ring cover 13, and a gap is generated between the hub member 14 and the ring cover 13 when the hub member 14 is disposed inside the ring cover 13.

[0065] Furthermore, the hub member 14, when viewed from above, has a through hole 142 extending through the hub member 14 along the rotation axis Ax1 at its central portion. The through hole 142 is a hole through which the eccentric shaft 54 ​​passes. The hub member 14 and the eccentric shaft 54 ​​are configured to rotate relative to each other about the rotation axis Ax1. Specifically, the inner diameter of the hub member 14 (the diameter of the through hole 142) is larger than the outer diameter of the eccentric shaft 54 ​​(its central portion 541), creating a gap between the hub member 14 and the eccentric shaft 54 ​​when the eccentric shaft 54 ​​is inserted through the through hole 142.

[0066] Furthermore, in this embodiment, the outer peripheral surface of the main body 11, which serves as a rotating member, becomes the contact surface, i.e., the contact surface, in the wheel body 102 that contacts the traveling surface. Therefore, a tire 103, for example made of rubber, is fitted onto the outer peripheral surface of the main body 11. Figure 1A and Figure 1B In the diagram, tire 103 is represented by an imaginary line (double-dotted line).

[0067] However, in this embodiment, the gear body 22 of the internal gear 2, the first outer ring 62 of the first bearing member 6, and the second outer ring 72 of the second bearing member 7 are fixed to the main body 11, which serves as a rotating member. Here, as an example, the gear body 22 and the first outer ring 62 are integrated with the main body 11. Furthermore, the main body 11 has an outer ring fixing frame 74 for fixing the second outer ring 72 (see reference). Figure 10 In particular, in this embodiment, the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 are integrally formed from a single metal component, thereby treating the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 as a seamless single component (body 11). The gear body 22, the first outer ring 62, and the outer ring fixing frame 74 are arranged from the output side of the rotating shaft Ax1 in the order of gear body 22, first outer ring 62, and outer ring fixing frame 74. Therefore, as... Figure 2 As shown, the inner circumferential surface of the main body 11 includes the inner circumferential surface 221 of the gear body 22 and the inner circumferential surface 621 of the first outer ring 62.

[0068] like Figures 4-6 As shown, the internal gear 2 is an annular component with internal teeth 21. In this embodiment, 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 arranged at equal intervals throughout the entire circumferential region of the inner circumferential surface of the internal gear 2. That is, the pitch circle of the internal teeth 21 is a perfect circle when viewed from above. The center of the pitch circle of the internal teeth 21 is located on the rotation axis Ax1. Furthermore, the internal gear 2 has a predetermined thickness along the direction of the rotation axis Ax1. The tooth directions of the internal teeth 21 are all parallel to the rotation axis Ax1. The dimension of the internal teeth 21 in the tooth direction is slightly smaller than that in the thickness direction of the internal gear 2.

[0069] Here, as described above, the internal gear 2 has an annular (ring-shaped) gear body 22 and multiple pins 23. The multiple pins 23 are held in a rotatable state on the inner circumferential surface 221 of the gear body 22, forming the internal teeth 21. In other words, the multiple pins 23 function as multiple teeth constituting the internal teeth 21. Specifically, on the inner circumferential surface 221 of the gear body 22, as... Figure 6As shown, multiple grooves are formed throughout the circumferential region. These multiple grooves are multiple gear-side grooves 222 that respectively serve as retaining structures for multiple pins 23 (see reference). Figure 4 In other words, the retaining structure of the multiple pins 23 includes multiple gear side grooves 222 formed on the inner circumferential surface 221 of the gear body 22. All of the multiple gear side grooves 222 are of the same shape and are equally spaced. All of the multiple gear side grooves 222 are parallel to the rotation axis Ax1 and are formed across the entire width of the gear body 22.

[0070] However, in this embodiment, since the gear body 22 is part of the main body 11 as described above, the plurality of gear side grooves 222 are formed only in the portion of the main body 11 corresponding to the gear body 22 (see reference). Figure 10 Multiple pins 23 are fitted into multiple gear side grooves 222, thereby assembling into the gear body 22 (body portion 11). Each of the multiple pins 23 is held in a self-rotating state within the gear side groove 222, and its movement in the circumferential direction of the gear body 22 is restricted by the gear side groove 222.

[0071] like Figures 4-6 As shown, the planetary gear 3 is an annular component with external teeth 31. In this embodiment, the planetary gear 3 has an annular shape, at least its outer circumferential surface being a perfect circle when viewed from above. External teeth 31 are formed on the outer circumferential surface of the annular planetary gear 3 along the circumferential direction of the planetary gear 3. All teeth constituting the external teeth 31 are of the same shape and are evenly spaced throughout the entire circumferential region of the outer circumferential surface of the planetary gear 3. That is, the pitch circle of the external teeth 31 is a perfect circle when viewed from above. The center C1 of the pitch circle of the external teeth 31 is located at a distance ΔL offset from the rotation axis Ax1 (see reference). Figure 4 The planetary gear 3 has a defined thickness along the direction of the rotation axis Ax1. The external teeth 31 are formed along the entire length of the planetary gear 3 in the thickness direction. The tooth direction of the external teeth 31 is parallel to the rotation axis Ax1. Unlike the internal gear 2, the external teeth 31 and the main body of the planetary gear 3 are integrally formed from a single metal component.

[0072] Here, regarding the planetary gear 3 assembly, the eccentric bearing 5 and the eccentric shaft 54 ​​are used. That is, as... Figure 5 and Figure 6As shown, 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. An eccentric bearing 5 is accommodated in the opening 33 of the planetary gear 3. Furthermore, the eccentric bearing 5 and the eccentric shaft 54 ​​are combined into the planetary gear 3 by inserting the eccentric shaft 54 ​​into the inner ring 51 of the eccentric bearing 5. With the eccentric bearing 5 and the eccentric shaft 54 ​​combined, when the eccentric shaft 54 ​​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, when the planetary gear 3 is internally tangent to the internal gear 2, the center C1 of the pitch circle of the external tooth 31 is offset by a distance ΔL (refer to the reference point) from the center of the pitch circle of the internal tooth 21 (rotation axis Ax1). Figure 4 Therefore, the external teeth 31 and the internal teeth 21 are at least partially opposed with a gap, and there is no overall meshing in the circumferential direction. However, since the planetary gear 3 oscillates (revolves) around the rotation axis Ax1 inside the internal gear 2, the external teeth 31 and the internal teeth 21 partially mesh. That is, through 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 of the internal gear 21 in the internal gear 2 is N more than the number of teeth of the external gear 31 in the planetary gear 3 (N is a positive integer). In this embodiment, as an example, N is "1", so the number of teeth of the planetary gear 3 (external teeth 31) is "1" more than the number of teeth of the internal gear 2 (internal teeth 21). This difference in the number of teeth between the planetary gear 3 and the internal gear 2 defines the reduction ratio of the output rotation to the input rotation in the gear unit 1.

[0076] Furthermore, in this embodiment, as an example, the thickness of the planetary gear 3 is smaller than the thickness of the gear body 22 in the internal gear 2. Strictly speaking, the thickness of the planetary gear 3 is smaller than the thickness of the portion of the main body 11 that functions as the gear body 22 (see reference). Figure 10 The external tooth 31 has a smaller dimension in the direction parallel to the rotation axis Ax1 than the internal tooth 21. Furthermore, the external tooth 31's dimension in the tooth direction (parallel to the rotation axis Ax1) is smaller than the internal tooth 21's dimension in the tooth direction (parallel to the rotation axis Ax1). In other words, in the direction parallel to the rotation axis Ax1, the external tooth 31 is contained within the tooth direction of the internal tooth 21.

[0077] In this embodiment, as described above, the relative rotation between the planetary gear 3 and the internal gear 2 is transmitted to the fixed member and the rotating member as a relative rotation between the gear body 22 and the plurality of internal pins 4. Figure 5 and Figure 6 As shown, the planetary gear 3 has multiple inner pin holes 32 for inserting multiple inner pins 4. The number of inner pin holes 32 is the same as the number of inner pins 4; in this embodiment, for example, there are eight inner pin holes 32 and eight inner pins 4. Each inner pin hole 32 is a hole that opens in a circular shape and passes through the planetary gear 3 along its thickness direction. The multiple (here, eight) inner pin holes 32 are arranged at equal intervals along the circumferential direction on a virtual circle concentric with the opening 33.

[0078] Multiple inner pins 4 are components that connect the planetary gear 3 to a fixed member or a rotating member. In this embodiment, in particular, the planetary gear 3 is connected to a fixed member (hub member 14, etc.) using multiple inner pins 4, and the gear body 22 is fixed to a rotating member (body part 11, etc.). Therefore, the planetary gear 3 is directly or indirectly connected to the fixed member (hub member 14, etc.) using multiple inner pins 4. Each of the multiple inner pins 4 is cylindrical. The diameter and length of the multiple inner pins 4 are the same. The diameter of the inner pin 4 is one size smaller than the diameter of the inner pin hole 32. Thus, the inner pin 4 is inserted into the inner pin hole 32 (see reference 32) with sufficient clearance between it and the inner circumferential surface of the inner pin hole 32. Figure 4 and Figure 5 ).

[0079] The retaining member 55 is a component that retains a plurality of inner pins 4. In this embodiment, as... Figure 8 and Figure 9As shown, the retaining member 55, viewed from above, is a perfect circle centered on the rotation axis Ax1, and is sized to the same degree as the hub member 14. The retaining member 55 has a plurality of retaining holes 551 into which a plurality of inner pins 4 are inserted. The number of retaining holes 551 is the same as the number of inner pins 4; in this embodiment, for example, there are eight retaining holes 551. Each retaining hole 551 is a hole that opens in a circular shape and penetrates the retaining member 55 in the thickness direction. The plurality of (here, eight) retaining holes 551 are arranged at equal intervals in the circumferential direction on a virtual circle concentric with the outer periphery of the retaining member 55. The diameter of the retaining holes 551 is greater than or equal to the diameter of the inner pins 4 but smaller than the diameter of the inner pin holes 32.

[0080] In this embodiment, the diameter of the retaining hole 551 is approximately the same as the diameter of the inner pin 4 and slightly larger than the diameter of the inner pin 4. Therefore, the movement of the inner pin 4 within the retaining hole 551 is restricted; that is, relative movement with respect to the center of the retaining hole 551 is prohibited. Thus, the inner pin 4 is held in the inner pin hole 32 in a state where it can revolve within the planetary gear 3, and is held in the retaining member 55 in a state where it cannot revolve within the retaining hole 551. Consequently, the oscillation component of the planetary gear 3, i.e., the revolution component of the planetary gear 3, is absorbed by the interlocking of the inner pin hole 32 and the inner pin 4. Through the multiple inner pins 4, the rotation (rotation component) of the planetary gear 3, excluding the oscillation component (revolution component), is transmitted to the retaining member 55.

[0081] Furthermore, in this embodiment, the diameter of the inner pin 4 is slightly larger than that of the retaining hole 551. Therefore, while the inner pin 4 is prohibited from revolving within the retaining hole 551 when inserted, it can still rotate within the retaining hole 551. That is, although the inner pin 4 is inserted into the retaining hole 551, it is not pressed into it, and thus it can rotate within the retaining hole 551. In this way, in the gear device 1 of this embodiment, each of the multiple inner pins 4 is held in a rotatable state within the retaining member 55, so that when the inner pin 4 revolves within the inner pin hole 32, the inner pin 4 itself can also rotate.

[0082] In summary, in this embodiment, the inner pin 4 is held in the planetary gear 3 in a state where it can both revolve and rotate within the inner pin hole 32, and is held in the retaining member 55 in a state where it can only rotate within the retaining hole 551. That is, the multiple inner pins 4 can revolve within the multiple inner pin holes 32 in a state where their rotation is unrestricted (a state where they can rotate). Therefore, when the rotation (rotation component) of the planetary gear 3 is transmitted to the retaining member 55 using the multiple inner pins 4, the inner pin 4 can revolve and rotate within the inner pin hole 32 while simultaneously rotating within the retaining hole 551. Therefore, since the inner pin 4 is in a state where it can rotate while revolving within the inner pin hole 32, it rolls relative to the inner circumferential surface of the inner pin hole 32. In other words, the inner pin 4 rolls on the inner circumferential surface of the inner pin hole 32 while revolving within the inner pin hole 32, thus minimizing losses caused by frictional resistance between the inner circumferential surface of the inner pin hole 32 and the inner pin 4.

[0083] Thus, in this embodiment, since it is inherently difficult to generate losses due to frictional resistance between the inner circumferential surface of the inner pin hole 32 and the inner pin 4, the inner roller can be omitted. Therefore, in this embodiment, each of the multiple inner pins 4 adopts a structure in which it directly contacts the inner circumferential surface of the inner pin hole 32. That is, in this embodiment, the inner pin 4 without the inner roller is inserted into the inner pin hole 32, forming a structure in which the inner pin 4 directly contacts the inner circumferential surface of the inner pin hole 32. As a result, the inner roller can be omitted, and the diameter of the inner pin hole 32 can be kept relatively small. Therefore, the planetary gear 3 can be miniaturized (especially reduced in diameter), and the gear assembly 1 as a whole can also be easily miniaturized. As long as the size of the planetary gear 3 remains constant, for example, the number of inner pins 4 can be increased to make the rotational transmission smoother, or the inner pins 4 can be thickened to increase strength. In addition, the number of components can be reduced to decrease the amount of inner rollers, which also helps to reduce the cost of the gear assembly 1.

[0084] The retaining member 55 is fixed to the hub member 14, which is a fixed member. Thus, the planetary gear 3 is connected to the fixed member (hub member 14) via the retaining member 55 using multiple inner pins 4. Since the retaining member 55 is fixed to the hub member 14, it is also included within the "fixed member". As a result, the multiple inner pins 4 are held directly or indirectly to the fixed member, and their relative positions with respect to the rotating shaft Ax1 are fixed. Furthermore, the opening on the input side of the rotating shaft Ax1 in the retaining hole 551 is closed, for example, by the hub member 14. Therefore, the movement of the inner pins 4 towards the input side of the rotating shaft Ax1 is restricted by the hub member 14.

[0085] Furthermore, the retaining member 55, when viewed from above, has a bearing hole 552 extending through it along the rotation axis Ax1 at its central portion. The bearing hole 552 is a hole through which the eccentric shaft 54 ​​passes, and it communicates with the through hole 142 of the hub member 14. Moreover, the retaining member 55 and the eccentric shaft 54 ​​are configured to rotate relative to each other about the rotation axis Ax1. Specifically, the inner diameter of the retaining member 55 (the diameter of the bearing hole 552) is larger than the outer diameter of the eccentric shaft 54 ​​(its central portion 541), creating a gap between the retaining member 55 and the eccentric shaft 54 ​​when the eccentric shaft 54 ​​is inserted through the bearing hole 552.

[0086] Here, the first inner ring 61 of the first bearing member 6 and the second inner ring 71 of the second bearing member 7 are fixed to the retaining member 55. In this embodiment, as an example, the first inner ring 61 is integrated with the retaining member 55. Specifically, the end of the first inner ring 61 on the output side of the rotation shaft Ax1 in the retaining member 55 is in the shape of a flange protruding circumferentially from the outer peripheral surface 553 of the retaining member 55. In particular, in this embodiment, the retaining member 55 and the first inner ring 61 are integrally formed from a single metal member, thereby treating the retaining member 55 and the first inner ring 61 as a seamless single component.

[0087] The first bearing member 6 is a component that rotatably supports a plurality of inner pins 4 on the gear body 22. In other words, the first bearing member 6 is a component for rotatably supporting a rotating component (body part 11, etc.) on a fixed component (hub member 14, etc.).

[0088] The second bearing member 7 is a component that rotatably supports a plurality of inner pins 4 on the gear body 22. In other words, the second bearing member 7 is a component used together with the first bearing member 6 to rotatably support a rotating member (body part 11, etc.) on a fixed member (hub member 14, etc.).

[0089] The first bearing member 6 and the second bearing member 7 are arranged side by side along the rotation axis Ax1, and multiple inner pins 4 are rotatably supported on the gear body 22 at two locations along the rotation axis Ax1. In this embodiment, the first inner ring 61 and the second inner ring 71 are fixed to a fixed member (hub member 14, etc.), and the first outer ring 62 and the second outer ring 72 are fixed to a rotating member (body part 11, etc.). Therefore, the first bearing member 6 and the second bearing member 7 rotatably support the rotating member (body part 11, etc.) on the fixed member (hub member 14, etc.) by means of the relative rotation of the inner and outer rings. The first bearing member 6 and the second bearing member 7 will be described in more detail in the section "(3.2) Bearing Members".

[0090] like Figure 2As shown, the eccentric shaft 54 ​​is a cylindrical component. The eccentric shaft 54 ​​has a central portion 541 and an eccentric portion 542. The central portion 541 is cylindrical, with at least its outer circumferential surface being perfectly circular when viewed from above. The center (central axis) of the central portion 541 coincides with the rotation axis Ax1. The eccentric portion 542 is disk-shaped, with at least its outer circumferential surface being perfectly circular when viewed from above. The center (central axis) of the eccentric portion 542 coincides with a center C1 offset from the rotation axis Ax1. Here, the distance ΔL between the rotation axis Ax1 and the center C1 (refer to...) Figure 2 The eccentricity of the eccentric portion 542 relative to the axis portion 541 is defined as follows: The eccentric portion 542 is a flange shape that protrudes from the outer circumference of the axis portion 541 at a portion other than both ends in the longitudinal direction (axial direction). According to the above structure, for the eccentric shaft 54, the eccentric portion 542 performs eccentric motion by rotating (rotating) the axis portion 541 around the rotation axis Ax1.

[0091] In this embodiment, the central portion 541 and the eccentric portion 542 are integrally formed from a single metal component, thereby achieving a seamless eccentric shaft 54. This eccentric shaft 54, with such a shape, is combined with the eccentric bearing 5 in the planetary gear 3. Therefore, when the planetary gear 3 is combined with the eccentric bearing 5 and the eccentric shaft 54, the planetary gear 3 oscillates around the rotation axis Ax1 when the eccentric shaft 54 ​​rotates.

[0092] The eccentric bearing 5 is a component having an outer eccentric ring 52 and an inner eccentric ring 51, absorbing the rotational component of the eccentric shaft 54, and transmitting only the oscillating component (revolutionary component) of the eccentric shaft 54 ​​to the planetary gear 3, excluding the rotational component of the eccentric shaft 54. In addition to the outer eccentric ring 52 and the inner eccentric ring 51, the eccentric bearing 5 also has multiple rolling elements 53 (see reference). Figure 4 ).

[0093] Both the outer eccentric ring 52 and the inner eccentric ring 51 are annular components. Both are perfectly circular rings when viewed from above. The inner eccentric ring 51 is smaller than the outer eccentric ring 52 and is positioned inside the outer eccentric ring 52. Here, the inner diameter of the outer eccentric ring 52 is larger than the outer diameter of the inner eccentric ring 51, thus creating a gap between the inner circumferential surface of the outer eccentric ring 52 and the outer circumferential surface of the inner eccentric ring 51.

[0094] Multiple rolling elements 53 are disposed in the gap between the outer ring 52 and the inner ring 51 of the eccentric outer ring. The multiple rolling elements 53 are arranged side-by-side along the circumferential direction of the outer ring 52. All 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 embodiment, as an example, the eccentric bearing 5 is constructed of a deep groove ball bearing using balls as rolling elements 53.

[0095] Here, the inner diameter of the inner ring 51 of the eccentric shaft 54 ​​matches the outer diameter of the eccentric portion 542 of the eccentric shaft 54. The eccentric bearing 5 is assembled with the eccentric shaft 54 ​​with the eccentric portion 542 inserted into the inner ring 51. Furthermore, the outer diameter of the outer ring 52 of the eccentric shaft 54 ​​matches the inner diameter (diameter) of the opening 33 of the planetary gear 3. The eccentric bearing 5 is assembled with the planetary gear 3 with the outer ring 52 embedded in the opening 33 of the planetary gear 3. In other words, the eccentric bearing 5, which is fitted with the eccentric portion 542 of the eccentric shaft 54, is accommodated in the opening 33 of the planetary gear 3.

[0096] Furthermore, in this embodiment, as an example, the width direction (the direction parallel to the rotation axis Ax1) of the inner eccentric ring 51 and the outer eccentric ring 52 of the eccentric bearing 5 is approximately the same as the thickness of the eccentric portion 542 of the eccentric shaft 54. In addition, the width direction of the inner eccentric ring 51 and the outer eccentric ring 52 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.

[0097] With the eccentric bearing 5 and eccentric shaft 54 ​​combined in the planetary gear 3, when the eccentric shaft 54 ​​rotates, the inner ring 51 of the eccentric bearing 5 rotates around a rotation axis Ax1 offset from the center C1 of the inner ring 51 (eccentric motion). At this time, the rotational component of the eccentric shaft 54 ​​is absorbed by the eccentric bearing 5. Therefore, through the eccentric bearing 5, the rotation of the eccentric shaft 54, except for its rotational component, is transmitted to the planetary gear 3, i.e., only the oscillating component (revolutionary component) of the eccentric shaft 54. Thus, with the planetary gear 3 combined with the eccentric bearing 5 and eccentric shaft 54, when the eccentric shaft 54 ​​rotates, the planetary gear 3 oscillates around the rotation axis Ax1.

[0098] like Figure 2As shown, the support body 8 is a component formed in an annular shape that supports a plurality of inner pins 4. The support body 8 has an annular shape in which at least its outer circumferential surface 81 is a perfect circle when viewed from above. The support body 8 has a plurality of support holes 82 into which the plurality of inner pins 4 are inserted respectively. The number of support holes 82 is the same as the number of inner pins 4; in this embodiment, for example, there are eight support holes 82. Each of the plurality of support holes 82 is a hole that opens in a circular shape and penetrates the support body 8 along the thickness direction. The plurality of (here, eight) support holes 82 are arranged at equal intervals along the circumferential direction on a virtual circle concentric with the outer circumferential 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 pins 4 but smaller than the diameter of the inner pin holes 32. In this embodiment, for example, the diameter of the support holes 82 is equal to the diameter of the retaining hole 551 formed in the retaining member 55. Therefore, the support body 8 supports the plurality of inner pins 4 in a state in which each of the plurality of inner pins 4 can rotate on its own axis. That is, each of the multiple inner pins 4 is held in a state in which it can rotate relative to either the retaining member 55 or the support body 8.

[0099] like Figure 3 As shown, the support body 8 is arranged opposite the planetary gear 3 from one side (input side) of the rotation axis Ax1. Furthermore, the support body 8 functions to bind the multiple inner pins 4 by inserting them into the multiple support holes 82. Thus, the support body 8 disperses the load acting on the multiple inner pins 4 when the rotation (rotation component) of the planetary gear 3 is transmitted to the fixed or rotating member.

[0100] Furthermore, the support body 8 is positioned by contacting its outer peripheral surface 81 with a plurality of pins 23. Here, the diameter of the outer peripheral surface 81 of the support body 8 is the same as the diameter of the virtual circle (addition circle) at the tip of the internal tooth 21 of the internal gear 2. Therefore, all of the pins 23 are in contact with the outer peripheral surface 81 of the support body 8. Thus, with the support body 8 positioned by the pins 23, the center of the support body 8 is positioned in a manner that overlaps with the center (rotation axis Ax1) of the internal gear 2. This allows for the centering of the support body 8, resulting in the centering of the plurality of internal pins 4 supported by the support body 8 also being achieved via the pins 23.

[0101] Furthermore, the multiple pins 23 constitute the internal teeth 21 of the internal gear 2. Therefore, when the gear body 22 rotates relative to the multiple internal pins 4, the support body 8 supporting the multiple internal pins 4 rotates relative to the internal gear 2 (gear body 22) together with the multiple internal pins 4. At this time, since the support body 8 is centered by the multiple pins 23, the support body 8 rotates smoothly relative to the internal gear 2 while its center remains on the rotation axis Ax1. Moreover, the outer peripheral surface 81 of the support body 8 rotates relative to the gear body 22 together with the multiple internal pins 4 in a state of tangency to the multiple pins 23. Therefore, if the gear body 22 of the internal gear 2 is regarded as the "outer ring" and the support body 8 as the "inner ring", 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 (needle roller bearing) and can rotate smoothly.

[0102] Furthermore, since the support body 8 has multiple pins 23 sandwiched between it and the gear body 22, the support body 8 also functions as a "movement limiter" to suppress the movement of the pins 23 in the direction of separation from the inner peripheral surface 221 of the gear body 22. That is, the multiple pins 23 are sandwiched between the outer peripheral surface 81 of the support body 8 and the inner peripheral surface 221 of the gear body 22, thereby suppressing the lifting of the multiple pins 23 from the inner peripheral surface 221 of the gear body 22. In summary, in this embodiment, each of the multiple pins 23 is restricted to move in the direction of separation from the gear body 22 by contacting the outer peripheral surface 81 of the support body 8.

[0103] In addition, in this embodiment, such as Figure 3 As shown, the support body 8 is located on the opposite side of the retaining member 55, separated from the planetary gear 3. That is, the support body 8, the planetary gear 3, and the retaining member 55 are arranged side by side along a direction parallel to the rotation axis Ax1. Furthermore, the support body 8 and the retaining member 55 together support both ends of the inner pin 4 in the length direction (parallel to the rotation axis Ax1), and the central portion of the inner pin 4 in the length direction is inserted through the inner pin hole 32 of the planetary gear 3. In this way, since the support body 8 and the retaining member 55 support both ends of the inner pin 4 in the length direction, it is difficult for the inner pin 4 to tilt. In particular, it is also easy to withstand the bending force (bending moment load) acting on the multiple inner pins 4 relative to the rotation axis Ax1.

[0104] Furthermore, in this embodiment, the support 8 is sandwiched between the planetary gear 3 and the housing 10 (cover 12) in a direction parallel to the rotation axis Ax1. Thus, the support 8 extends towards the output side of the rotation axis Ax1 (…). Figure 9 The movement of the left side of the support body 8 is restricted by the housing 10. The movement of the inner pin 4, which protrudes from the support body 8 to the output side of the rotating shaft Ax1 through the support hole 82 of the support body 8, to the output side of the rotating shaft Ax1 is also restricted by the housing 10.

[0105] The first bearing 91 and the second bearing 92 are respectively mounted on the central portion 541 of the eccentric shaft 54. 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 542 in the shaft center portion 541 in a direction parallel to the rotation shaft Ax1, sandwiching the eccentric portion 542. Viewed from the eccentric portion 542, the first bearing 91 is positioned on the output side of the rotation shaft Ax1. Viewed from the eccentric portion 542, the second bearing 92 is positioned on the input side of the rotation shaft Ax1. In this embodiment, as an example, both the first bearing 91 and the second bearing 92 are constructed from deep groove ball bearings using balls as rolling elements.

[0106] The first bearing 91 is held in the housing 10. Specifically, a circular recess is formed on the input side surface of the rotating shaft Ax1 in the cover 12, and the first bearing 91 is mounted in the housing 10 by inserting it into the recess. On the other hand, the second bearing 92 is held in the retaining member 55. Specifically, the second bearing 92 is mounted in the retaining member 55 by inserting it into the bearing hole 552 of the retaining member 55. In other words, the second bearing 92 is fitted into the gap between the retaining member 55 and the eccentric shaft 54. Thus, the two portions on both sides of the eccentric portion 542 of the axial portion 541 of the eccentric shaft 54 ​​in the direction parallel to the rotating shaft Ax1 are held in a rotatable manner.

[0107] The counterweight 56 ​​is a component through which the central portion 541 of the eccentric shaft 54 ​​is inserted. Here, as in the gear device 1 of this embodiment, when the input rotation, which is on the high-speed rotation side, is accompanied by eccentric motion, if the weight balance of the rotating body rotating at high speed is not achieved, vibration or the like may occur. Therefore, the counterweight is provided to achieve weight balance of the rotating body, composed of at least one of the inner ring 51 of the eccentric shaft and the component (eccentric shaft 54) that rotates together with the inner ring 51, relative to the rotation axis Ax1. The counterweight 56 ​​is formed asymmetrically with respect to the rotation axis Ax1; in this embodiment, as an example, it is formed in a generally fan-shaped form. Here, the counterweight 56 ​​functions by adding weight to the side of the outer ring 52 of the eccentric shaft opposite to the center C1 when viewed from the rotation axis Ax1, so that the weight balance of the eccentric shaft 54 ​​approaches evenly in the circumferential direction from the rotation axis Ax1.

[0108] The spacer 93 is a component through which the central portion 541 of the eccentric shaft 54 ​​is inserted. The spacer 93 is an annular component and is disposed between the eccentric portion 542 of the eccentric shaft 54 ​​and the first bearing 91. Thus, a certain amount of spacing of the spacer 93 is ensured between the eccentric portion 542 and the first bearing 91.

[0109] In addition, such as Figure 3 As shown, the gear device 1 of this embodiment also includes multiple oil seals 94, 95, 96, etc. Oil seal 94 is fitted between the hub member 14 and the ring cover 13, filling the gap between them. Oil seals 95 and 96, when fitted to the axial center 541 of the eccentric shaft 54, are disposed within the through hole 142 of the hub member 14, thereby filling the gap between the hub member 14 and the eccentric shaft 54. The internal space of the housing 10 sealed by these multiple oil seals 94, 95, and 96 constitutes a sealed space.

[0110] Furthermore, a lubricant is injected into the sealed space (the internal space of the housing 10). The lubricant is a liquid and can flow within the sealed space. Therefore, when the gear device 1 is in use, 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 disclosure includes liquid or gel-like substances. The term "gel-like" as used herein refers to a state having intermediate properties between liquid and solid, including a colloid state composed of both a liquid phase and a solid phase. For example, emulsions in which the dispersant is a liquid phase and the dispersed substance is a liquid phase, and suspensions in which the dispersed substance is a solid phase, are states referred to as gels or sols, which are included in the term "gel-like". Moreover, states in which the dispersant is a solid phase and the dispersed substance is a liquid phase are also included in the term "gel-like". In this embodiment, as an example, the lubricant is a liquid lubricating oil.

[0111] In the gear assembly 1 with the above-described structure, a rotational force is applied as input to the eccentric shaft 54, which rotates around the rotation axis Ax1, causing the planetary gear 3 to oscillate (revolve) around the rotation axis Ax1. At this time, the planetary gear 3 is internally tangent to the internal gear 2 on the inner side, and oscillates in a state where a part of the external teeth 31 meshes with a part of the internal teeth 21. Therefore, the meshing position of the internal teeth 21 and the external teeth 31 moves along the circumferential direction of the internal gear 2. As a result, a relative rotation corresponding to the difference in the number of teeth between the planetary gear 3 and the internal gear 2 is generated between the two gears (internal gear 2 and planetary gear 3). Furthermore, since the planetary gear 3 is connected to a fixed member (hub member 14, etc.) by multiple inner pins 4, and the gear body 22 is fixed to a rotating member (body part 11, etc.), the relative rotation between the planetary gear 3 and the internal gear 2 is removed from the internal gear 2. At this time, only the rotational component (rotational component) of the planetary gear 3, excluding the oscillating component (revolutionary component) of the planetary gear 3, is extracted from the internal gear 2. As a result, a rotational output that is reduced in speed at a relatively high reduction ratio, corresponding to the difference in the number of teeth between the two gears, can be obtained from the rotating member to which the gear body 22 is fixed.

[0112] Furthermore, in the gear device 1 of this embodiment, as described above, the difference in the number of teeth between the internal gear 2 and the planetary gear 3 defines the reduction ratio of the output rotation relative to the input rotation in the gear device 1. That is, when the number of teeth of the internal gear 2 is set to "V1" and the number of teeth of the planetary gear 3 is set to "V2", the reduction ratio R1 is expressed by the following formula 1. Here, it is assumed that the gear body 22 is fixed to the rotating member and the relative rotation between the planetary gear 3 and the internal gear 2 is taken out from the internal gear 2.

[0113] R1=V1 / (V1-V2)…(Equation 1)

[0114] 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 "30", and the number of teeth V2 of the planetary gear 3 is "29", with a difference in the number of teeth (V1-V2) of "1". Therefore, according to Equation 1 above, the reduction ratio R1 becomes "30". In this case, viewed from the input side of the rotating shaft Ax1, when the eccentric shaft 54 ​​rotates clockwise one revolution (360 degrees) around the rotating shaft Ax1, the gear body 22 rotates clockwise around the rotating shaft Ax1 by the amount of the tooth difference "1" (approximately 12.0 degrees).

[0115] According to the gear device 1 of this embodiment, such a high reduction ratio R1 can be achieved by a combination of a primary gear (internal gear 2 and planetary gear 3).

[0116] 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 first bearing component 6 and a second bearing component 7, and may also include, for example, a spline bushing as a structural element.

[0117] (3.2) Bearing components

[0118] Next, the structure of the first bearing member 6 and the second bearing member 7 of this embodiment will be described in more detail.

[0119] like Figure 2 and Figure 3 As shown, the first bearing component 6 has a first inner ring 61 and a first outer ring 62. The first inner ring 61 and the first outer ring 62 are in a rotatable relative relationship about the rotation axis Ax1. Figure 2 and Figure 3 As shown, the first bearing component 6 has a first outer ring 62 and a first inner ring 61, as well as a plurality of bearing pins 63.

[0120] like Figures 7-9As shown, both the first inner ring 61 and the first outer ring 62 are annular components. Both the first inner ring 61 and the first outer ring 62 are circular rings that, when viewed from above, form a perfect circle centered on the rotation axis Ax1. The first inner ring 61 is one ring smaller than the first outer ring 62 and is positioned inside the first outer ring 62. Here, since the inner diameter of the first outer ring 62 is larger than the outer diameter of the first inner ring 61, the inner circumferential surface 621 of the first outer ring 62 and the outer circumferential surface 611 of the first inner ring 61 (see reference) Figure 7 Gaps are created between them.

[0121] As described above, the first inner ring 61 is fixed to the retaining member 55. The outer peripheral surface 611 of the first inner ring 61, when viewed from above, is concentric with the outer peripheral surface 553 of the retaining member 55. In this embodiment, the first inner ring 61 is particularly integrated with the retaining member 55, and the first inner ring 61 is formed by a flange-shaped portion protruding throughout the entire circumference of the outer peripheral surface 553 of the retaining member 55. That is, in Figure 7 In the diagram, the portion outside the outer peripheral surface 553, represented by the imaginary line (double-dotted line), corresponds to the first inner ring 61. Since the retaining member 55 is fixed to the hub member 14, the result is that the first inner ring 61 is fixed relative to the fixing member (hub member 14, etc.).

[0122] As described above, the first outer ring 62 is fixed to the main body 11, which serves as a rotating member. The inner circumferential surface 621 of the first outer ring 62 is concentric with the outer circumferential surface 611 of the first inner ring 61 when viewed from above. In this embodiment, the first outer ring 62 is particularly integrated with the main body 11, and a portion of the main body 11 constitutes the first outer ring 62.

[0123] A plurality of bearing pins 63 are disposed between the first inner ring 61 and the first outer ring 62. The plurality of bearing pins 63 are arranged side-by-side along the circumferential direction of the first outer ring 62. All of the plurality of bearing pins 63 are metal components of the same shape and are equally spaced throughout the entire circumferential region of the first outer ring 62. Each of the plurality of bearing pins 63 is cylindrical. The diameter and length of the plurality of bearing pins 63 are identical.

[0124] Here, multiple bearing pins 63 are held between the first inner ring 61 and the first outer ring 62 in a rotatable state. Furthermore, the multiple bearing pins 63 are sandwiched between the outer circumferential surface 611 of the first inner ring 61 and the inner circumferential surface 621 of the first outer ring 62. Therefore, when the first outer ring 62 rotates relative to the first inner ring 61, each of the multiple bearing pins 63 rotates (self-rotates) along with the rotation of the first outer ring 62. Thus, the first bearing member 6 constitutes a needle roller bearing.

[0125] In this embodiment, multiple bearing pins 63 are held on the inner circumferential surface 621 of the first outer ring 62 in a rotatable state. Specifically, as... Figure 9 As shown, multiple grooves are formed on the inner circumferential surface 621 of the first outer ring 62, covering the entire circumferential region. These multiple grooves are multiple bearing-side grooves 622 that respectively serve as retaining structures for multiple bearing pins 63 (see reference). Figure 7 In other words, the retaining structure of the plurality of bearing pins 63 includes a plurality of bearing side grooves 622 formed on the inner circumferential surface 621 of the first outer ring 62. All of the plurality of bearing side grooves 622 are of the same shape and are equally spaced. All of the plurality of bearing side grooves 622 are formed parallel to the rotating shaft Ax1 and extend across the entire width of the gear body 22.

[0126] However, in this embodiment, as described above, since the first outer ring 62 is part of the main body 11, the plurality of bearing side grooves 622 are only formed in the main body 11 at the portion corresponding to the first outer ring 62 (see reference). Figure 10 Multiple bearing pins 63 are fitted into multiple bearing side grooves 622 and thus assembled into the first outer ring 62 (main body 11). Each of the multiple bearing pins 63 is held in the bearing side groove 622 in a rotatable state and is restricted by the bearing side groove 622 to move in the circumferential direction of the first outer ring 62.

[0127] Thus, since the first bearing member 6 is a needle roller bearing, it is easy to bear the radial load primarily in the first bearing member 6. Compared with deep groove ball bearings, needle roller bearings have a larger radial load tolerance, so by equipping such a first bearing member 6, the radial load tolerance (load capacity) of the gear assembly 1 as a whole can be increased.

[0128] That is, the first bearing member 6 uses multiple bearing pins 63, which have substantially the same structure as the multiple pins 23 constituting the internal teeth 21 of the internal gear 2, as rolling elements. In this embodiment, in particular, the number and diameter of the bearing pins 63 and pins 23 are the same. That is, as Figure 4 and Figure 7 As shown, there are 30 pins 23 and 30 bearing pins 63. The diameter of pin 23 is... (Refer to Figure 4 ) and the diameter of bearing pin 63 (Refer to Figure 7 )same

[0129] Furthermore, the configuration of pins 23 and bearing pins 63 is identical when viewed from one side in the direction of the rotation axis Ax1. Therefore, pins 23 and bearing pins 63 are arranged to overlap each other in a direction parallel to the rotation axis Ax1. Specifically, the plurality of gear side grooves 222 formed on the inner circumferential surface 221 of the gear body 22, which serve as retaining structures for the plurality of pins 23, and the plurality of bearing side grooves 622 formed on the inner circumferential surface 621 of the first outer ring 62, which serve as retaining structures for the plurality of bearing pins 63, share a common configuration. That is, when both the plurality of gear side grooves 222 and the plurality of bearing side grooves 622 are formed on the gear body 22, which is part of the main body 11, or on the first outer ring 62, the configuration is identical when viewed from one side in the direction of the rotation axis Ax1 (see reference). Figure 2 Therefore, the configuration of the pin 23 held in the gear side groove 222 and the bearing pin 63 held in the bearing side groove 622 is the same when viewed from one side in the direction of the rotation axis Ax1.

[0130] However, the shapes of the gear side groove 222, which serves as the retaining structure for pin 23, and the bearing side groove 622, which serves as the retaining structure for bearing pin 63, are different. In this embodiment, the depth D1 of the gear side groove 222 (refer to...) Figure 4 The depth D2 of the bearing side groove 622 (refer to) Figure 7 The depths of the multiple gear side grooves 222 and the multiple bearing side grooves 622 are different (D1>D2). Specifically, when viewed from one side along the direction of the rotation axis Ax1, both the gear side grooves 222 and the bearing side grooves 622 have a diameter equal to that of the pin 23 or the bearing pin 63. The groove has an arc-shaped bottom surface with a diameter greater than the above. In other words, the bottom surfaces of both the gear side groove 222 and the bearing side groove 622 have a radius of curvature greater than or equal to the radius of the pin 23 or the bearing pin 63. Here, as an example, the bottom surfaces of both the gear side groove 222 and the bearing side groove 622 have the same radius of curvature as the pin 23 or the bearing pin 63. Furthermore, the bearing side groove 622 is made shallower than the gear side groove 222.

[0131] Furthermore, in this embodiment, due to the diameter of pin 23 Diameter of bearing pin 63 same Therefore, compared to the multiple gear side grooves 222, the ratio of the depth of the multiple bearing side grooves 622 to the diameter of the retaining pin is reduced. That is, the depth D2 of the bearing side groove 622 is smaller relative to the diameter of the bearing pin 63. ratio The depth D1 of the gear side groove 222 relative to the diameter of the pin 23 ratio Small. In this embodiment, as an example, the depth D1 of the gear side groove 222 is relative to the diameter of the pin 23. ratio It is "1 / 2". On the other hand, the depth D2 of the bearing side groove 622 is relative to the diameter of the bearing pin 63. ratio The value is "1 / 3". Here, at least the depth D2 of the bearing side groove 622 is relative to the diameter of the bearing pin 63. ratio Preferably, it is "1 / 2" or less, more preferably "1 / 3" or less, for example, it can be about "1 / 4".

[0132] In summary, the primary function of pin 23 is to exert a force in the rotational direction about the rotation axis Ax1, while the primary function of bearing pin 63 is to exert a radial force. Therefore, the bearing side groove 622 that keeps bearing pin 63 in place only needs to be at a minimum depth D2 to prevent bearing pin 63 from falling off. Conversely, by minimizing the depth D2 of the bearing side groove 622, it is advantageous to reduce the frictional resistance between the inner surface of the bearing side groove 622 and the bearing pin 63, and to reduce the loss of the first bearing member 6. Furthermore, minimizing the depth D2 of the bearing side groove 622 also allows lubricant to easily enter the bearing side groove 622.

[0133] As explained above, in this embodiment, pin 23 and bearing pin 63 have the same outer diameter and the same configuration when viewed from one side in the direction of the rotation axis Ax1. Therefore, in this embodiment, the central axis Ax2 (refer to...) becomes the center when pin 23 rotates (spins on its own axis). Figure 10 ) and the central axis Ax3 that becomes the center when bearing pin 63 rotates (rotates) (refer to Figure 10 They are located on a straight line. In other words, each of the plurality of bearing pins 63 is concentrically arranged with each of the plurality of pins 23.

[0134] Furthermore, in this embodiment, each of the plurality of bearing pins 63 and each of the plurality of pins 23 are separate units. When the rotation (self-rotation) of pin 23 and the rotation (self-rotation) of bearing pin 63 are originally asynchronous, the separate pins 23 and bearing pins 63 can rotate independently. In other words, the rotation (self-rotation) of pin 23 and the rotation (self-rotation) of bearing pin 63 are unlikely to interfere with each other or hinder each other's rotation. However, pins 23 and bearing pins 63 can rotate synchronously to some extent.

[0135] Furthermore, in this embodiment, the surface roughness of the outer peripheral surface 611 of the first inner ring 61 is smaller than the surface roughness of a surface adjacent to the outer peripheral surface 611 of the first inner ring 61. That is, the surface roughness of the outer peripheral surface 611 is smaller compared to the two end faces in the rotation axis Ax1 direction of the first inner ring 61. The term "surface roughness" as used in this disclosure refers to the degree of roughness of an object's surface; the smaller the value, the less unevenness (roughness) and the smoother the surface. In this embodiment, as an example, the surface roughness is set to the arithmetic mean roughness (Ra). For example, through processes such as grinding, the surface roughness of the outer peripheral surface 611 of the first inner ring 61 is smaller than that of any surface other than the outer peripheral surface 611 of the first inner ring 61. In this structure, the rotation of the first outer ring 62 relative to the first inner ring 61 becomes smoother.

[0136] Furthermore, in this embodiment, the hardness of the outer peripheral surface 611 of the first inner ring 61 is lower than that of the peripheral surfaces of the plurality of bearing pins 63, and higher than that of the inner peripheral surface 621 of the first outer ring 62. The term "hardness" as used in this disclosure refers to the degree of hardness of an object; the hardness of a metal is, for example, expressed by the size of the indentation formed when a steel ball is pressed against it with 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 (hardening) the hardness of metal components include, for example, alloying or heat treatment. In this embodiment, as an example, the hardness of the outer peripheral surface 611 of the first inner ring 61 is increased by treatments such as carburizing and quenching. In this structure, even due to the rotation of the first outer ring 62 relative to the first inner ring 61, wear particles are unlikely to be generated, and the smooth rotation of the first bearing member 6 can be maintained for a long time.

[0137] Such a surface structure with low surface roughness and high hardness is also preferably suitable for the outer peripheral surface 81 of the support body 8. That is, in this embodiment, the support body 8 functions as the "inner ring" of the same needle roller bearing as the first bearing member 6, so an appropriate surface roughness and hardness are preferably applied to the outer peripheral surface 81 of the support body 8, which is equivalent to the outer peripheral surface of the inner ring.

[0138] like Figure 2 and Figure 3 As shown, the second bearing component 7 has a second outer ring 72 and a second inner ring 71. The second inner ring 71 and the second outer ring 72 are in a rotatable relative relationship about the rotation axis Ax1. Figure 2 and Figure 3 As shown, the second bearing component 7 has a second outer ring 72 and a second inner ring 71, as well as a plurality of second rolling elements 73.

[0139] like Figure 2As shown, both the second inner ring 71 and the second outer ring 72 are annular components. Both the second inner ring 71 and the second outer ring 72 are circular rings that, when viewed from above, form a perfect circle centered on the rotation axis Ax1. The second inner ring 71 is one ring smaller than the second outer ring 72 and is positioned inside the second outer ring 72. Here, since the inner diameter of the second outer ring 72 is larger than the outer diameter of the second inner ring 71, a gap is created between the inner circumferential surface of the second outer ring 72 and the outer circumferential surface of the second inner ring 71. Furthermore, in this embodiment, as... Figure 3 As shown, the inner diameter of the second outer ring 72 is larger than the outer diameter of the first inner ring 61 but smaller than the inner diameter of the first outer ring 62. The outer diameter of the second inner ring 71 is smaller than the outer diameter of the first inner ring 61.

[0140] The second inner ring 71 is fixed to the retaining member 55. Here, the inner diameter of the second inner ring 71 matches the outer diameter of the retaining member 55 (outer peripheral surface 553). The second bearing member 7 is combined with the retaining member 55 with the retaining member 55 inserted into the second inner ring 71. Since the retaining member 55 is fixed to the hub member 14, the second inner ring 71 is fixed relative to the fixed member (hub member 14, etc.).

[0141] The second outer ring 72 is fixed to the main body 11, which serves as a rotating member. The outer diameter of the second outer ring 72 is related to the outer ring fixing frame 74 in the main body 11 (see reference). Figure 3 The inner diameters of the bearing components are the same. The second bearing component 7 is combined with the main body 11 in a state where the second outer ring 72 is embedded in the outer ring fixing frame 74 of the main body 11. In other words, the second bearing component 7, which is a rotating component, is housed in the outer ring fixing frame 74 of the main body 11, in a state where it is assembled with the retaining component 55.

[0142] A plurality of second rolling elements 73 are disposed in the gap between the second inner ring 71 and the second outer ring 72. The plurality of second rolling elements 73 are arranged side-by-side along the circumferential direction of the second outer ring 72. All of the plurality of second rolling elements 73 are metal components of the same shape and are evenly spaced throughout the entire circumferential region of the second outer ring 72. In this embodiment, as an example, the second bearing member 7 is constituted by a deep groove ball bearing using balls as the second rolling elements 73. That is, the second bearing member 7 includes a deep groove ball bearing.

[0143] Thus, since the second bearing member 7 is a deep groove ball bearing, it is easy for the second bearing member 7 to primarily bear the load in the thrust direction (along the direction of the rotation axis Ax1). That is, the second bearing member 7 bears at least the load in the direction of the rotation axis Ax1. Although the radial load tolerance of a deep groove ball bearing is smaller than that of a needle roller bearing, the thrust load tolerance is larger. Therefore, by equipping such a second bearing member 7, the thrust load tolerance (load capacity) of the gear device 1 as a whole can be increased.

[0144] In summary, the gear assembly 1 of this embodiment, by including the first bearing member 6 and the second bearing member 7, can easily withstand radial loads and thrust loads. Specifically, the gear assembly 1 can withstand radial loads via the first bearing member 6, which is a needle roller bearing, and thrust loads via the second bearing member 7, which is a deep groove ball bearing. Furthermore, the gear assembly 1, through the first bearing member 6 and the second bearing member 7, rotatably supports multiple inner pins 4 on the gear body 22 at two locations along the rotation axis Ax1. Therefore, the gear assembly 1 can easily withstand any bending force (bending moment load) on the rotation axis Ax1.

[0145] Thus, in the gear device 1 of this embodiment, even without using crossed roller bearings, it can withstand three types of loads: radial load, thrust load, and bending force on the rotating shaft Ax1, ensuring the required rigidity. Moreover, by sharing the load with the first bearing member 6 and the second bearing member 7, it also helps to extend the lifespan of each of the first bearing member 6 and the second bearing member 7.

[0146] Next, refer to Figure 3 and Figure 10 This describes the relative positional relationship between the first bearing member 6 and the second bearing member 7, and their arrangement. Specifically, in this embodiment, the first bearing member 6 and the second bearing member 7 rotatably support multiple inner pins 4 on the gear body 22 at two locations along the rotation axis Ax1. Therefore, the first bearing member 6 and the second bearing member 7 are arranged side-by-side along a direction parallel to the rotation axis Ax1.

[0147] In this embodiment, such as Figure 3 As shown, the internal gear 2, the first bearing member 6, and the second bearing member 7 are arranged side-by-side from the output side of the rotating shaft Ax1 in the order of internal gear 2, first bearing member 6, and second bearing member 7. That is, the first bearing member 6 is located between the internal gear 2 and the second bearing member 7 in a direction parallel to the rotating shaft Ax1. In other words, the first bearing member 6 and the second bearing member 7 are located on the same side in the direction of the rotating shaft Ax1 with respect to the plurality of pins 23. In this embodiment, both the first bearing member 6 and the second bearing member 7 are located on the input side of the rotating shaft Ax1 with respect to the plurality of pins 23. Figure 3 (Right side).

[0148] Furthermore, in the direction of rotation axis Ax1, a plurality of bearing pins 63 are located between the second bearing member 7 and the plurality of pins 23. That is, the first bearing member 6 is located on the input side of rotation axis Ax1 relative to the plurality of pins 23. Figure 3(on the right side), the second bearing member 7 is located on the input side of the rotation shaft Ax1 relative to the first bearing member 6. Figure 3 (to the right). Therefore, in a direction parallel to the rotation axis Ax1, a plurality of bearing pins 63 of the first bearing member 6 are sandwiched between the second bearing member 7 and a plurality of pins 23.

[0149] Here, the internal gear 2, the first bearing component 6, and the second bearing component 7 are arranged side by side with approximately no gap in a direction parallel to the rotation axis Ax1. Specifically, as... Figure 10 As shown, when the main body 11 is divided into three regions in a direction parallel to the rotation axis Ax1, these three regions function as the internal gear 2, the first outer ring 62 of the first bearing member 6, and the outer ring fixing frame 74 for fixing the second bearing member 7, respectively. That is, in this embodiment, the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 constitute a seamless component (main body 11), therefore, in Figure 10 In the diagram, the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 are distinguished by the boundary lines represented by imaginary lines (double-dotted lines).

[0150] With the configuration described above, one end of the plurality of bearing pins 63 in the direction of rotation axis Ax1 contacts the second outer ring 72 or the second inner ring 71. Specifically, as Figure 10 As shown, the input side of the rotating shaft Ax1 of bearing pin 63 ( Figure 10 The right end face of the bearing pin 63 contacts the second outer ring 72 of the second bearing member 7. Therefore, the movement of the bearing pin 63 toward the input side of the rotation shaft Ax1 is restricted by the second outer ring 72. Furthermore, the other ends of the plurality of bearing pins 63 in the direction of the rotation shaft Ax1 contact the pin 23. Specifically, as... Figure 10 As shown, the output side of the rotating shaft Ax1 of bearing pin 63 ( Figure 10 The left end face of the bearing pin 63 contacts the pin 23. Therefore, the movement of the bearing pin 63 toward the output side of the rotating shaft Ax1 is restricted by the pin 23.

[0151] Furthermore, in the gear device 1 of this embodiment, each of the plurality of inner pins 4 is at least partially disposed at the same position as the first bearing member 6 and the second bearing member 7 in the axial direction (rotation axis Ax1 direction) of the first bearing member 6. That is, as Figure 10 As shown, in a direction parallel to the rotation axis Ax1, the inner pin 4 positions at least a portion of itself in the same position as the first bearing member 6 and the second bearing member 7.

[0152] In other words, each of the plurality of inner pins 4 has at least a portion disposed inside the first bearing member 6 and the second bearing member 7. In summary, in this embodiment, as described above, when viewed from the side in the direction of the rotation axis Ax1, the plurality of inner pins 4 are located inside the second bearing member 7. Furthermore, in relation to the first bearing member 6, when viewed from the side in the direction of the rotation axis Ax1, the plurality of inner pins 4 are also located inside the first bearing member 6. Thus, with at least a portion of each of the plurality of inner pins 4 arranged axially in the same position as the first bearing member 6 and the second bearing member 7, the size of the gear assembly 1 in the direction parallel to the rotation axis Ax1 can be minimized.

[0153] Furthermore, the first bearing member 6 and the second bearing member 7 are positioned relative to the retaining member 55 that holds the plurality of inner pins 4 as follows: When viewed from the direction of rotation axis Ax1, the first bearing member 6 and the second bearing member 7 are located outside the retaining member 55. Specifically, the first inner ring 61 of the first bearing member 6, being a flange shape that protrudes circumferentially from the outer peripheral surface 553 of the retaining member 55, is located outside the retaining member 55 when viewed from the direction of rotation axis Ax1. The second bearing member 7, being combined with the retaining member 55 in a state where the retaining member 55 is inserted into the second inner ring 71, is also located outside the retaining member 55 when viewed from the direction of rotation axis Ax1.

[0154] (4) Applicable examples

[0155] Next, refer to Figure 11 This section describes an example of the applicability of the gear device 1 in this embodiment.

[0156] In this embodiment, the gear device 1 and the wheel body 102 together constitute the wheel device W1. In other words, the wheel device W1 of this embodiment includes the gear device 1 and the wheel body 102. The wheel body 102 rolls on the travel surface by the rotation output when the plurality of inner pins 4 rotate relative to the gear body 22. In this embodiment, the main body 11, cover 12, and ring cover 13, which are "rotating members" in the housing 10 that constitutes the outer contour of the gear device 1, constitute the wheel body 102. That is, in the wheel device W1 of this embodiment, the gear device 1 rotates as input rotation of the eccentric shaft 54 ​​and rotates as output rotation of the rotating member (main body 11, etc.) to which the gear body 22 is fixed, thereby rotating the wheel body 102 and rolling on the travel surface. Here, a tire 103, for example made of rubber, is fitted on the outer peripheral surface of the main body 11, which is the contact surface of the wheel body 102 that contacts the travel surface, i.e., the contact surface.

[0157] And, for example Figure 11As shown, the wheel assembly W1, which uses the gear device 1, together with the vehicle body 100 constitutes the vehicle V1. In other words, the vehicle V1 of this embodiment includes the wheel assembly W1 and the vehicle body 100. The vehicle body 100 holds the wheel assembly W1. That is, the vehicle V1 of this embodiment uses the wheel assembly W1, which includes the gear device 1, as wheels, and the wheel body 102 rotates and rolls on the travel surface, thereby traveling on a flat travel surface formed by the floor surface or the like. Figure 11 In the example, vehicle V1 includes four wheel assemblies W1, which are respectively mounted at the four corners of a rectangular body 100 viewed from above. Such a vehicle V1 includes a drive source 101 for imparting driving force to the wheel assemblies W1. Figure 11 In the example, the vehicle V1 is equipped with four drive sources 101, which are arranged as "hub motors" that correspond one-to-one with the wheel assembly W1.

[0158] The drive source 101 generates a driving force to oscillate the planetary gears 3 of the gear assembly 1 included in each wheel assembly W1. Specifically, the drive source 101 is a power source such as a motor (electric motor). The power generated by the drive source 101 is transmitted to the eccentric shaft 54 ​​in the gear assembly 1. That is, the drive source 101 causes the planetary gears 3 to oscillate by rotating the eccentric shaft 54 ​​of the corresponding wheel assembly W1 around the rotation axis Ax1. As a result, the rotation (input rotation) generated by the drive source 101 is reduced in the gear assembly 1 with a relatively high reduction ratio, and the wheel body 102 is rotated with a relatively high torque.

[0159] In this way, by individually driving multiple (four in this case) wheel assemblies W1, the vehicle V1 can move in any direction on the travel surface. For example, the vehicle V1 can travel in a straight line by driving multiple wheel assemblies W1 to rotate in the same direction at the same speed, and by imparting a rotational difference between the multiple wheel assemblies W1, it can change its direction of travel to perform cornering or turning. Therefore, the vehicle V1 can perform forward, reverse, and left / right turning. The turning mentioned here includes in-situ turning and turning on the spot.

[0160] In this way, the vehicle V1, using the wheel assembly W1 as its drive wheels, can move freely on the travel surface under the control of the drive source 101. In particular, the vehicle V1 of this embodiment is suitable for vehicles requiring relatively high torque, such as Automated Guided Vehicles (AGVs). This AGV, acting as an automated guided vehicle, moves autonomously on the travel surface, for example, with the transported goods loaded on its body 100. Thus, the vehicle V1 can transport the transported goods placed in one location to another.

[0161] In this vehicle V1, the wheel assembly W1 needs to support not only the weight of the vehicle body 100, but also the weight of the cargo loaded on the vehicle body 100. That is, not only when the vehicle V1 is moving, but also when the vehicle V1 is parked, there are sometimes situations where a relatively large load acts on the wheel assembly W1 in the radial direction (orthogonal to the rotation axis Ax1). In this embodiment, the wheel assembly W1 uses a needle roller bearing with a bearing pin 63 as the "rolling element (roller)" as the first bearing member 6 of the gear assembly 1, so it can withstand a relatively large load for radial loads.

[0162] Furthermore, when the vehicle V1 travels on curves or turns, a thrust load (along the direction of the rotation axis Ax1) also acts on the wheel assembly W1, but the thrust load is much smaller than the radial load. Moreover, since the wheel assembly W1 of this embodiment uses a deep groove ball bearing as the second bearing member 7 of the gear assembly 1, the second bearing member 7 can bear such a thrust load. In short, the wheel assembly W1 using the gear assembly 1 of this embodiment is particularly suitable for vehicles V1, such as automated guided vehicles, which tend to experience relatively large radial loads but not such large thrust loads.

[0163] Furthermore, in this embodiment, since the gear assembly 1 extracts the rotational force of the gear body 22 as its output, when the wheel assembly W1 is driven, the first outer ring 62, which is integrated with the gear body 22, also rotates around the rotation axis Ax1. When the first outer ring 62 rotates, the multiple bearing pins 63 held by the multiple bearing side grooves 622 of the first outer ring 62 also rotate around the rotation axis Ax1. As a result, in the first bearing member 6, which mainly bears the radial load, the bearing pins 63 located in the vertical direction of the rotation axis Ax1 change constantly, thus easily avoiding the situation where a portion of the bearing pins 63 are concentrated under load.

[0164] Furthermore, in this embodiment, the drive source 101 is not included in the components of the wheel assembly W1, but it is not limited to this example; the drive source 101 may also be included in the components of the wheel assembly W1. In this case, the wheel assembly W1 includes the drive source 101, the gear assembly 1, and the wheel body 102.

[0165] (5) Variations

[0166] Embodiment 1 is merely one of the various embodiments of this disclosure. Various modifications can be made to Embodiment 1, depending on the design, etc., as long as the objectives of this disclosure are achieved. Furthermore, the accompanying drawings referenced in this disclosure are schematic diagrams, and the size and thickness ratios of the constituent elements in the drawings may not necessarily reflect actual dimensional ratios. Hereinafter, variations of Embodiment 1 are listed. The variations described below can be appropriately combined and applied.

[0167] In embodiment 1, a gear device 1 with a single planetary gear 3 is illustrated; however, the gear device 1 may include multiple planetary gears 3. For example, when the gear device 1 includes two planetary gears 3, it is preferable that these two planetary gears 3 are arranged with a 180-degree phase difference around the rotation axis Ax1. Furthermore, when the gear device 1 includes three planetary gears 3, it is preferable that these three planetary gears 3 are arranged with a 120-degree phase difference around the rotation axis Ax1. In this way, when the multiple planetary gears 3 are evenly arranged circumferentially around the rotation axis Ax1, weight balance among the multiple planetary gears 3 can be achieved.

[0168] Furthermore, the tooth profile and other structural (principles) can be appropriately modified. The gear device 1 can be, for example, an eccentric oscillating type gear device employing a planetary gear 3 with a circular tooth profile (see, for example, Japanese Patent Application Publication No. 2017-137989). Additionally, the gear device 1 can be, for example, an eccentric oscillating type gear device that converts the rotation of the input gear into eccentric oscillation via a spur gear and crankshaft (see, for example, Japanese Patent Application Publication No. 2020-85213).

[0169] In addition, such as Figure 12 As shown, each of the plurality of bearing pins 63 can be integrally formed with each of the plurality of pins 23. That is, in Figure 12 In the example, a pin is extended axially, with one part functioning as bearing pin 63 and the other part functioning as pin 23. In this modified structure, pin 23 rotates together with bearing pin 63 and cannot rotate independently, but this reduces the number of components.

[0170] Furthermore, each of the plurality of inner pins 4 is configured, at least a portion thereof, in the direction of the rotation axis Ax1 at the same position as the first bearing member 6 or the second bearing member 7, which is not a necessary configuration in the gear device 1. That is, each of the plurality of inner pins 4 is arranged side by side (opposite to) the first bearing member 6 or the second bearing member 7 in the direction of the rotation axis Ax1.

[0171] Furthermore, the number of internal pins 4, the number of pins 23 (the number of teeth of internal teeth 21), and the number of teeth of external teeth 31 described in Embodiment 1 are merely examples and can be appropriately changed.

[0172] Furthermore, the second bearing component 7 is not limited to a deep groove ball bearing; for example, it can be a crossed roller bearing or an angular contact ball bearing. In addition, the second bearing component 7 can be a structure that can withstand radial loads, thrust loads (in the direction along the rotation axis Ax1), and bending forces (bending moment loads) on the rotation axis Ax1, such as a four-point contact ball bearing.

[0173] In addition, the gear assembly 1 may also include bearing components such as deep groove ball bearings, crossed roller bearings, or angular contact ball bearings, in addition to the second bearing component 7.

[0174] Furthermore, the eccentric bearing 5 is not limited to deep groove ball bearings; for example, it can be an angular contact ball bearing. Moreover, the eccentric bearing 5 is not limited to ball bearings; for example, it can be a roller bearing such as a cylindrical roller bearing, a needle roller bearing, or a tapered roller bearing, where the rolling elements 53 are composed of non-spherical "rollers".

[0175] Furthermore, the materials of the various structural elements of the gear device 1 are not limited to metal; for example, they can be resins such as engineering plastics.

[0176] Furthermore, the gear device 1 is not limited to a structure that extracts the rotational force of the gear body 22 as an output when the multiple inner pins 4 rotate relative to the gear body 22. For example, the planetary gear 3 can be connected to a rotating member by multiple inner pins 4, and the gear body 22 can be fixed to a fixed member, thereby extracting the rotational force (rotation component) of the planetary gear 3 as an output when the multiple inner pins 4 rotate relative to the gear body 22.

[0177] In addition, lubricants are not limited to liquid substances such as lubricating oil (oil), but can also be gel-like substances such as lubricating grease.

[0178] Additionally, the gear assembly 1 may include internal rollers. That is, in the gear assembly 1, it is not necessary for each of the multiple internal pins 4 to be in direct contact with the inner circumferential surface 321 of the internal pin hole 32; internal rollers may be sandwiched between each of the multiple internal pins 4 and the internal pin hole 32. In this case, the internal rollers are mounted on the internal pins 4 and can rotate about the internal pins 4 as an axis. Furthermore, it is not necessary for each of the multiple internal pins 4 to be held in a rotating state in the retaining member 55.

[0179] Furthermore, each of the plurality of inner pins 4 may be configured in the same position as the first bearing member 6 or the second bearing member 7 in the direction of rotation axis Ax1, provided that at least a portion of each inner pin 4 is disposed within the range of the first bearing member 6 or the second bearing member 7 in the direction of rotation axis Ax1.

[0180] Furthermore, it is not necessary in the gear assembly 1 for multiple inner pins 4 to connect the planetary gear 3 to the fixed member (hub member 14, etc.) via the retaining member 55. For example, multiple inner pins 4 can be inserted into the retaining holes formed in the hub member 14, thereby directly connecting the planetary gear 3 to the fixed member (hub member 14, etc.).

[0181] Furthermore, the positioning of multiple inner pins 4 relative to the support body 8 in both the circumferential and radial directions is not necessary in the gear device 1. For example, the support body 8 may have a slit-like support hole 82 extending radially, with the multiple inner pins 4 positioned relative to the support body 8 only in the circumferential direction. Conversely, the support body 8 may also have multiple inner pins 4 positioned relative to the support body 8 only in the radial direction.

[0182] Furthermore, the inclusion of a counterweight 56 ​​as in Embodiment 1 is not a necessary structure for the gear device 1. That is, the counterweight 56 ​​can be omitted, and weight reduction can be achieved by reducing the weight of a portion of the rotating body (such as the inner ring 51 of the eccentric inner ring and the eccentric shaft 54), thereby achieving weight balance of the rotating body relative to the rotating shaft Ax1. With this structure, the number of components can be reduced, and suppression of vibrations caused by weight balancing of the high-speed rotating body can also be expected.

[0183] Furthermore, the vehicle V1 only needs to include one or more wheel assemblies W1, and the number of wheel assemblies W1 is not limited to four (four wheels). As an example, the vehicle V1 may include one to three wheel assemblies W1, or it may include five or more wheel assemblies W1. In addition, the drive source 101 for driving the wheel assemblies W1 is not limited to a one-to-one arrangement of hub motors relative to the wheel assemblies W1, and one drive source 101 can be provided for multiple wheel assemblies W1. Moreover, the wheel assemblies W1 in Embodiment 1 only need to be provided on the drive wheels of the vehicle V1. For example, in addition to the wheel assemblies W1 that serve as drive wheels, the vehicle V1 may also include one or more driven wheels. Driven wheels are "non-drive wheels" that do not receive power from the drive source 101 and therefore do not generate driving force for the vehicle V1 to move.

[0184] Furthermore, the vehicle V1 using the wheel device W1 including the gear device 1 of Embodiment 1 is not limited to an automated guided vehicle (AGV). For example, it can also be a monitoring vehicle or a camera vehicle, or a vehicle other than a transport vehicle. In addition, the vehicle V1 is not limited to an autonomous vehicle that is not driven by anyone. For example, it can also be a vehicle that is entered and operated (driven) by a person or a vehicle that is remotely operated by a person.

[0185] Furthermore, the gear device 1 in Embodiment 1 is not limited to its use as a wheel device W1, but can also be applied to robots such as horizontal articulated robots, i.e., so-called Selective Compliance Assembly Robot Arm (SCARA) type robots. In this case, the gear device 1, together with the drive source 101 that generates the driving force for oscillating the planetary gear 3, constitutes an actuator, which is mounted on the robot. Moreover, the applicability of the gear device 1 and the actuator is not limited to horizontal articulated robots; for example, it can 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 link robots. Among robots other than industrial robots, examples include home robots, nursing robots, or medical robots.

[0186] Furthermore, the integrated structure of the gear body 22, the first outer ring 62, and the outer ring fixing frame 74, as in Embodiment 1, is not necessary for the gear device 1. For example, the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 can be separate (individual components), and the gear body 22, the first outer ring 62, and the outer ring fixing frame 74 can be fixed to the main body 11 by pressing, welding, or bonding.

[0187] Furthermore, the integration of the first inner ring 61 with the retaining member 55 as in Embodiment 1 is not a necessary structure for the gear device 1. For example, the first inner ring 61 and the retaining member 55 can be separate (individual components), and the first inner ring 61 can be fixed to the retaining member 55 by means of pressing, welding, or bonding. In addition, the second inner ring 71 can be integrated with the retaining member 55.

[0188] (Implementation Method 2)

[0189] The internal meshing planetary gear device 1A (hereinafter also simply referred to as "gear device 1A") of this embodiment is as follows: Figure 13 and Figure 14 As shown, the structure of the first bearing member 6A differs from that of the gear device 1 in Embodiment 1. Hereinafter, for structures identical to those in Embodiment 1, the same reference numerals will be used, and descriptions will be omitted where appropriate. Figure 13 This is a schematic cross-sectional view of gear assembly 1A. Figure 14 yes Figure 13 The sectional view along line B1-B1 and its enlarged partial view. However, in Figure 14 In the middle, for components other than the eccentric shaft 54, although they are cross-sections, the section lines are omitted.

[0190] However, in the aforementioned related technologies, crossed roller bearings are used as bearing components, which can hinder the simplification of the overall structure of the gear device 1 due to the relatively complex structure of the crossed roller bearings. The gear device 1A of this embodiment provides an internal meshing planetary gear device 1A with a simplified structure that is easy to achieve through the following structure.

[0191] That is, such as Figure 13 and Figure 14 As shown, the gear device 1A of this embodiment includes an internal gear 2, a planetary gear 3, a plurality of inner pins 4, and a first bearing member 6A. The internal gear 2 has an annular gear body 22 and a plurality of pins 23 that are held in a rotatable state on the inner circumferential surface 221 of the gear body 22 and form internal teeth 21. The planetary gear 3 has external teeth 31 that partially mesh with the internal teeth 21. The plurality of inner pins 4, when respectively inserted into a plurality of inner pin holes 32 formed in the planetary gear 3, revolve within the inner pin holes 32 and rotate relative to the gear body 22. The first bearing member 6A has a first inner ring 61 and a first outer ring 62, and a plurality of bearing pins 63. The plurality of bearing pins 63 are held in a rotatable state between the first inner ring 61 and the first outer ring 62. Here, the plurality of pins 23 and the plurality of bearing pins 63 have different diameters and different holding structures.

[0192] According to this configuration, the first bearing member 6A has a first inner ring 61, a first outer ring 62, and a plurality of bearing pins 63. That is, the first bearing member 6A is a needle roller bearing with the bearing pins 63 as "rolling elements (rollers)," capable of withstanding relatively large radial loads. Furthermore, since the diameters and retaining structures of the plurality of pins 23 and the plurality of bearing pins 63 are different, the diameters and retaining structures of the bearing pins 63 are designed to easily withstand various envisioned loads. Therefore, compared to related technologies using crossed roller bearings as bearing members, the gear device 1A of this embodiment has the advantage of easily achieving structural simplification.

[0193] That is, the diameters of the plurality of pins 23 and the plurality of bearing pins 63 are different. In this embodiment, compared with embodiment 1, the diameter of the bearing pins 63 in the first bearing member 6A is... (Refer to Figure 14 The ratio relative to length increases. That is, in this embodiment, a coarse pin is used as the bearing pin 63. Therefore, as Figure 13 As shown, bearing pin 63 has a larger diameter than pin 23. In other words, the diameter of bearing pin 63 is... Diameter of pin 23 (Refer to Figure 4Therefore, in the first bearing member 6A of this embodiment, compared with the first bearing member 6 of embodiment 1, the radial load-bearing capacity can be increased, and the radial load-bearing capacity can also be increased as a whole as the gear device 1A.

[0194] Furthermore, in this embodiment, the retaining structures for the plurality of pins 23 and the plurality of bearing pins 63 are different. The term "different retaining structures" as used in this disclosure refers to certain differences between the retaining structures used to retain the pins 23 and the retaining structures used to retain the bearing pins 63. For example, as described in Embodiment 1, the housings with different shapes (depths) for the gear side groove 222 serving as the retaining structure for the pins 23 and the bearing side groove 622 serving as the retaining structure for the bearing pins 63 are also included in the category of "different retaining structures." As another example, the housings with different materials or hardness, etc., in the retaining structures for the plurality of pins 23 and the plurality of bearing pins 63 are also included in the category of "different retaining structures."

[0195] In this embodiment, firstly, similar to embodiment 1, the depth D1 of the gear side groove 222 (refer to...) Figure 4 The depth D2 of the bearing side groove 622 (refer to) Figure 14 The depths of the multiple gear side grooves 222 and the multiple bearing side grooves 622 are different (D1>D2). Specifically, the bearing side groove 622 has a diameter of the bearing pin 63 when viewed from one side in the direction of the rotation axis Ax1. The groove has an arc-shaped bottom surface with a diameter greater than the above. In other words, the bottom surface of the bearing side groove 622 has a larger radius of curvature than the bottom surface of the gear side groove 222. As an example, the bottom surface of the bearing side groove 622 has the same radius of curvature as the bearing pin 63. Moreover, the bearing side groove 622 is shallower than the gear side groove 222.

[0196] Furthermore, in this embodiment, the diameter of pin 23 Diameter of bearing pin 63 different However, compared to the multiple gear side grooves 222, the ratio of the depth of the multiple bearing side grooves 622 to the diameter of the retaining pin is set smaller. That is, the depth D2 of the bearing side groove 622 is smaller relative to the diameter of the bearing pin 63. ratio The depth D1 of the gear side groove 222 relative to the diameter of the pin 23 ratio Small. In this embodiment, as an example, the depth D2 of the bearing side groove 622 is relative to the diameter of the bearing pin 63. ratio Less than "1 / 4".

[0197] In summary, in this embodiment, the difference between the retaining structure of pin 23 (gear side groove 222) and the retaining structure of bearing pin 63 (bearing side groove 622) includes not only the difference in depth (D1 and D2) but also the difference in the radius of curvature of the bottom surface. Thus, even though the machining of the main body 11 for forming the gear side groove 222 and bearing side groove 622 becomes more complex when the shapes of the gear side groove 222 and bearing side groove 622 are different, it is still possible to reliably retain pins 23 and bearing pins 63 with different diameters respectively.

[0198] Furthermore, in this embodiment, since the outer diameters (diameters) of pins 23 and bearing pins 63 are different, the central axis Ax2, which serves as the center of rotation (self-rotation) of pin 23, and the central axis Ax3, which serves as the center of rotation (self-rotation) of bearing pin 63, are offset from each other. In other words, the plurality of bearing pins 63 and the plurality of pins 23 are not concentrically arranged. In this embodiment, as... Figure 13 As shown, the central axis Ax3 of bearing pin 63 is located inside the central axis Ax2 of pin 23 (on the side of the rotation axis Ax1).

[0199] Furthermore, in this embodiment, the diameter of the support body 8 (outer peripheral surface 81) is smaller than the diameter of the virtual circle (tip circle) at the front end of the internal tooth 21 of the internal gear 2. Therefore, the outer peripheral surface 81 of the support body 8 does not contact the plurality of pins 23, creating a gap between the outer peripheral surface 81 of the support body 8 and the plurality of pins 23.

[0200] As a variation of implementation method 2, such as Figure 15 As shown, each of the plurality of bearing pins 63 can be integrally formed with each of the plurality of pins 23. That is, in Figure 15 In this example, a pin is extended axially, with one part functioning as bearing pin 63 and the other part functioning as pin 23. Here, due to the diameter of bearing pin 63... Diameter of pin 23 Because they are different, the central axis Ax2, which serves as the center of rotation (self-rotation) of pin 23, is aligned with the central axis Ax2, which serves as the center of rotation (self-rotation) of bearing pin 63. This allows the integrated pin 23 and bearing pin 63 to rotate around the central axis Ax2. In this modified structure, pin 23 rotates together with bearing pin 63 and cannot rotate independently, but this reduces the number of components.

[0201] As another variation of embodiment 2, the second bearing member 7 can be omitted appropriately. That is, the gear device 1A only needs to have an internal gear 2, a planetary gear 3, multiple internal pins 4 and a first bearing member 6A, and the second bearing member 7 can be omitted.

[0202] As another variation of embodiment 2, the diameter of bearing pin 63 is... It can be compared to the diameter of pin 23. Small. Furthermore, the number of bearing pins 63 and 23 can be different.

[0203] Furthermore, as another variation of Embodiment 2, the diameter of the outer peripheral surface 81 of the support 8 can be the same as the diameter of the virtual circle (tip circle) passing through the front end of the internal tooth 21 in the internal gear 2. In this case, similar to Embodiment 1, the support 8 is positioned by contacting the outer peripheral surface 81 with the plurality of pins 23.

[0204] The structure of Embodiment 1 (including variations) can be appropriately combined with the structure (including variations) described in Embodiment 1.

[0205] (Implementation Method 3)

[0206] like Figure 16 and Figure 17 As shown, the structure of the first bearing member 6B in the internal meshing planetary gear device 1B of this embodiment (hereinafter also simply referred to as "gear device 1B") differs from that of the gear device 1A in Embodiment 2. Hereinafter, the same reference numerals will be used to refer to structures identical to those in Embodiment 2, and descriptions will be omitted as appropriate. Figure 16 This is a schematic cross-sectional view of gear assembly 1B. Figure 17 yes Figure 16 The sectional view along line B1-B1 and its enlarged partial view. However, in Figure 17 In the middle, for components other than the eccentric shaft 54 ​​and the cage 64, although they are in cross-section, the cross-sectional lines are omitted.

[0207] In this embodiment, the first bearing member 6B is configured such that a plurality of bearing pins 63 are movable relative to the first outer ring 62 in the circumferential direction of the first outer ring 62. On the other hand, in the internal gear 2, similar to embodiment 2, the relative movement of the plurality of pins 23 relative to the gear body 22 in the circumferential direction of the gear body 22 is restricted. Therefore, the plurality of bearing pins 63 are movable relative to the plurality of pins 23 in the circumferential direction of the first outer ring 62. As a result, in the gear device 1B of this embodiment, the plurality of bearing pins 63 rotate relative to the plurality of pins 23 as the plurality of inner pins 4 rotate relative to the gear body 22.

[0208] Specifically, the first bearing component 6B has Figure 17The cage 64 (retainer) is shown. A plurality of bearing pins 63 are respectively arranged in a rotatable state between the inner circumferential surface 621 of the first outer ring 62 and the outer circumferential surface 611 of the first inner ring 61, and are held by the cage 64. The cage 64 holds the plurality of bearing pins 63 at equal intervals in the circumferential direction of the first outer ring 62. Furthermore, the cage 64 is not fixed relative to the inner circumferential surface 621 of the first outer ring 62 and the outer circumferential surface 611 of the first inner ring 61, and can rotate relative to the first inner ring 61 and the first outer ring 62 respectively about the rotation axis Ax1. Thus, with the rotation of the cage 64, the plurality of bearing pins 63 held by the cage 64 move along the circumferential direction of the first outer ring 62. In other words, the retaining structure for the plurality of bearing pins 63 includes the cage 64 disposed between the first outer ring 62 and the first inner ring 61. The cage 64 is, for example, made of metal.

[0209] In summary, in this embodiment, the retaining structure of pin 23 is a gear side groove 222, while the retaining structure of bearing pin 63 is a cage 64. The retaining structures of pin 23 and bearing pin 63 differ in their manner. In this case, it is sufficient to form only the gear side groove 222 as the retaining structure for the main body 11, thus simplifying the machining of the main body 11.

[0210] As a variation of embodiment 3, the diameter of bearing pin 63 is... It can be used with the diameter of pin 23 same The diameter of bearing pin 63 It can be compared to the diameter of pin 23. Small.

[0211] As another variation of embodiment 3, the cage 64 is not necessary, as long as the multiple inner pins 4 can rotate relative to the multiple bearing pins 63 relative to the multiple pins 23 along with the relative rotation of the multiple inner pins 4 relative to the gear body 22. Moreover, the material of the cage 64 is not limited to metal; for example, it can be a resin such as engineering plastic.

[0212] The structure of Embodiment 2 (including variations) can be appropriately combined with the structure (including variations) described in Embodiment 1.

[0213] (Summarize)

[0214] As described above, the first-type internal meshing planetary gear assembly (1, 1A, 1B) includes an internal gear (2), a planetary gear (3), multiple inner pins (4), a first bearing member (6, 6A, 6B), and a second bearing member (7). The internal gear (2) has an annular gear body (22) and multiple pins (23) that are held in a rotatable state on the inner circumferential surface (221) of the gear body (22) and 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) revolve within the multiple inner pin holes (32) formed in the planetary gear (3) and rotate relative to the gear body (22). The first bearing member (6, 6A, 6B) and the second bearing member (7) rotatably support the multiple inner pins (4) on the gear body (22) at two locations in the direction of the rotation axis (Ax1). The first bearing component (6, 6A, 6B) has a first inner ring (61), a first outer ring (62), and a plurality of bearing pins (63). The plurality of inner pins (4) are located inside the second bearing component (7) when viewed from one side in the direction of the rotation axis (Ax1).

[0215] According to this configuration, the first bearing member (6, 6A, 6B) and the second bearing member (7) rotatably support multiple inner pins (4) on the gear body (22) at two locations in the direction of the rotation axis (Ax1), thus the multiple inner pins (4) are supported at two points on the gear body (22). Therefore, compared to a single-point support where multiple inner pins (4) are supported on the gear body (22) at one location in the direction of the rotation axis (Ax1), it is easier to withstand loads such as bending forces (bending moment loads) on the rotation axis (Ax1). Moreover, the first bearing member (6, 6A, 6B) has a first inner ring (61), a first outer ring (62), and multiple bearing pins (63). That is, the first bearing member (6, 6A, 6B) is a needle roller bearing with bearing pins (63) as "rolling elements (rollers)," and can withstand relatively large loads for radial loads. Furthermore, since the bearing is supported at two points and the second bearing member (7) is located outside the plurality of inner pins (63) when viewed from one side in the direction of the rotation axis (Ax1), the limited space inside the plurality of inner pins (63) can be used to create a relatively simple structure. Therefore, it has the advantage of being easy to simplify the structure.

[0216] In the second form of the internal meshing planetary gear device (1, 1A, 1B), based on the first form, the first bearing member (6, 6A, 6B) and the second bearing member (7) are located on the same side in the direction of the rotation axis (Ax1) relative to the plurality of pins (23).

[0217] Based on this configuration, multiple inner pins (4) can be effectively supported at two points, and miniaturization in the direction of the rotation axis (Ax1) is also easily achieved.

[0218] In the third form of the internal meshing planetary gear assembly (1, 1A, 1B), based on the first or second form, a retaining member (55) is also included to hold multiple inner pins (4). The first bearing member (6, 6A, 6B) and the second bearing member (7) are located outside the retaining member (55) when viewed from one side in the direction of the rotation axis (Ax1).

[0219] Based on this shape, miniaturization in the direction of the rotation axis (Ax1) can be easily achieved.

[0220] In the fourth form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to third forms, each of the multiple bearing pins (63) is integrated with each of the multiple pins (23).

[0221] Based on this form, it is easy to keep the number of parts to a minimum.

[0222] In the fifth form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to third forms, each of the multiple bearing pins (63) and each of the multiple pins (23) are separate.

[0223] According to this configuration, the rotation of the bearing pin (63) and the rotation of the pin (23) are unlikely to interfere with each other.

[0224] In the sixth form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to fifth forms, multiple bearing pins (63) are located between the second bearing member (7) and multiple pins (23) in the direction of the rotation axis (Ax1).

[0225] Based on this configuration, the first bearing components (6, 6A, 6B) can easily and effectively bear radial loads.

[0226] In the seventh form of the internal meshing planetary gear assembly (1, 1A, 1B), based on any one of the first to sixth forms, the second bearing member (7) has a second outer ring (72) and a second inner ring (71). One end of the plurality of bearing pins (63) in the direction of the rotation axis (Ax1) contacts the second outer ring (72) or the second inner ring (71).

[0227] According to this configuration, the movement of the bearing pin (63) toward one side in the direction of the rotation axis (Ax1) can be restricted.

[0228] In the eighth form of the internal meshing planetary gear assembly (1, 1A, 1B), based on any one of the first to seventh forms, the retaining structure of the multiple pins (23) includes multiple gear side grooves (222) formed on the inner circumferential surface (221) of the gear body (22). The retaining structure of the multiple bearing pins (63) includes multiple bearing side grooves (622) formed on the inner circumferential surface (621) of the first outer ring (62). Compared with the multiple gear side grooves (222), the depth of the multiple bearing side grooves (622) is smaller in ratio to the diameter of the retaining pin.

[0229] Based on this configuration, it is easy to reduce the frictional resistance between the inner surface of the bearing side groove (622) and the bearing pin (63).

[0230] In the ninth form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to eighth forms, it is configured to extract the rotational force of the gear body (22) as output when the multiple inner pins (4) rotate relative to the gear body (22).

[0231] According to this configuration, a component integrated with the gear body (22) or the gear body (22) can be used as a rotating component.

[0232] In the tenth form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to ninth forms, the second bearing member (7) bears at least the load along the direction of the rotation axis (Ax1).

[0233] According to this configuration, the second bearing component (7) can withstand the load in the thrust direction.

[0234] In the eleventh form of the internal meshing planetary gear device (1, 1A, 1B), based on any one of the first to tenth forms, the second bearing member (7) includes a deep groove ball bearing.

[0235] According to this configuration, the second bearing component (7) can withstand the load in the direction of thrust.

[0236] The twelfth type of wheel assembly (W1) includes: an internal meshing planetary gear assembly (1, 1A, 1B) of any of the first to eleventh types; and a wheel body (102) that rolls on the travel surface by rotational output when a plurality of inner pins (4) rotate relative to the gear body (22).

[0237] Based on this form, it has the advantage of easily simplifying the structure.

[0238] The vehicle in the thirteenth form (V1) includes the wheel assembly (W1) of the twelfth form and the body (100) that holds the wheel assembly (W1).

[0239] Based on this form, it has the advantage of easily simplifying the structure.

[0240] Regarding the structures of the second to eleventh forms, these are not essential for the internal meshing planetary gear devices (1, 1A, 1B) and can be omitted appropriately.

[0241] Explanation of reference numerals in the attached figures

[0242] 1. 1A, 1B Internal meshing planetary gear assembly

[0243] 2 Internal gears

[0244] 3 planetary gears

[0245] 4. Domestic sales

[0246] 6, 6A, 6B First Bearing Components

[0247] 7 Second bearing component

[0248] 21 internal teeth

[0249] 22 Gear Body

[0250] 23 sales

[0251] 31 external teeth

[0252] 32-hole inner pin

[0253] 55 retaining components

[0254] 61 First Inner Circle

[0255] 62 First Outer Ring

[0256] 63 bearing pin

[0257] 71 Second Inner Circle

[0258] 72 Second Outer Ring

[0259] 100 body

[0260] 102 wheel body

[0261] 221 (inner circumferential surface of the gear body)

[0262] 222 Gear Side Groove

[0263] 621 (Inner circumferential surface of the first outer ring)

[0264] 622 bearing side groove

[0265] Ax1 Rotational Axis

[0266] V1 vehicles

[0267] W1 wheel assembly

[0268] Industrial applicability

[0269] According to embodiments of this disclosure, a simplified internal meshing planetary gear assembly, wheel assembly, and vehicle with an easily achievable structure can be provided.

Claims

1. An internal meshing planetary gear device, wherein, include: An internal gear has an annular gear body and a plurality of pins that are held on the inner circumferential surface of the gear body in a rotatable state and form internal teeth. A planetary gear having external teeth that partially mesh with the internal teeth; Multiple inner pins, when respectively inserted into multiple inner pin holes formed in the planetary gear, revolve within the inner pin holes and rotate relative to the gear body. and The first bearing member and the second bearing member rotatably support the plurality of inner pins on the gear body at two locations in the direction of rotation. The first bearing member and the second bearing member are located on the same side in the direction of rotation relative to the plurality of pins constituting the internal teeth. The first bearing component has a first inner ring, a first outer ring, and a plurality of bearing pins. The plurality of inner pins are located inside the second bearing member when viewed from one side in the direction of the rotation axis.

2. The internal meshing planetary gear device according to claim 1, wherein, The internal meshing planetary gear assembly also includes retaining members for holding the plurality of internal pins. The first bearing member and the second bearing member are located outside the retaining member when viewed from one side in the direction of the rotation axis.

3. The internal meshing planetary gear device according to claim 1 or 2, wherein, Each of the plurality of bearing pins is integral with each of the plurality of pins constituting the internal teeth.

4. The internal meshing planetary gear device according to claim 1 or 2, wherein, Each of the plurality of bearing pins and each of the plurality of pins constituting the internal teeth are separate entities.

5. The internal meshing planetary gear device according to claim 1 or 2, wherein, The plurality of bearing pins are located in the direction of rotation between the second bearing member and the plurality of pins constituting the internal teeth.

6. The internal meshing planetary gear device according to claim 1 or 2, wherein, The second bearing component has a second outer ring and a second inner ring. One end of the plurality of bearing pins in the direction of rotation is in contact with the second outer ring or the second inner ring.

7. The internal meshing planetary gear device according to claim 1 or 2, wherein, The retaining structure of the plurality of pins constituting the internal teeth includes a plurality of gear side grooves formed on the inner circumferential surface of the gear body. The retaining structure of the plurality of bearing pins includes a plurality of bearing side grooves formed on the inner circumferential surface of the first outer ring. Compared to the multiple gear side grooves, the depth of the multiple bearing side grooves is smaller in ratio to the diameter of the retaining pin.

8. The internal meshing planetary gear device according to claim 1 or 2, wherein, The configuration is such that when the plurality of inner pins rotate relative to the gear body, the rotational force of the gear body is extracted as an output.

9. The internal meshing planetary gear device according to claim 1 or 2, wherein, The second bearing component bears at least the load along the direction of the rotation axis.

10. The internal meshing planetary gear device according to claim 1 or 2, wherein, The second bearing component includes a deep groove ball bearing.

11. A wheel assembly, wherein, include: The internal meshing planetary gear device according to any one of claims 1 to 10; and The wheel body rolls on the travel surface by the rotational output of the plurality of inner pins when they rotate relative to the gear body.

12. A vehicle, wherein, include: The wheel assembly as claimed in claim 11; and Maintain the vehicle body of the wheel assembly.

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