Planetary gear device

Abstract

The utility model provides a kind of internal meshing planetary gear device.The internal meshing planetary gear device includes the input side cover of the end portion of the input side bracket of input side, by making crankshaft and input side cover contact, to limit the movement of crankshaft to input side, and the contact portion of the input side cover is contacted with the crankshaft is formed with the micro pit forming portion with multiple micro pits.Formed by this, it can ensure oil film on the input side cover and reduce the risk of abrasion and the risk of efficiency decline.

Description

Technical Field

[0001] This utility model relates to an internal meshing planetary gear device. Background Technology

[0002] Patent documents 1 and 2 disclose an internal meshing planetary gear device having a crankshaft supported by bearings. In this internal meshing planetary gear device, a disc-shaped cover is installed on the input side support to restrict the axial movement of the crankshaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2024-003287

[0006] Patent Document 2: Chinese Patent Application No. CN118293188A Utility Model Content

[0007] Problems to be solved by utility models

[0008] In the internal meshing planetary gear assembly disclosed in the aforementioned patent documents, during operation, the crankshaft and bearings are subjected to an axial component force, causing them to rotate continuously with the crankshaft and bearing retainers pressed against the cover. Consequently, since lubricant has difficulty reaching the periphery of these components, insufficient lubrication may occur, leading to accelerated wear of the crankshaft, retainer, and cover. As a result, the lifespan of the internal meshing planetary gear assembly is shortened, and efficiency decreases due to increased sliding resistance.

[0009] The purpose of this invention is to provide an internal meshing planetary gear device that can ensure an oil film on a cover that restricts the axial movement of the crankshaft, thereby reducing the risk of wear and efficiency loss.

[0010] Solution for solving the problem

[0011] The first aspect of this utility model provides an internal meshing planetary gear device, comprising: an internal gear having an annular gear body and a plurality of pins, the plurality of pins being held in a rotatable state in a plurality of pin grooves formed on the inner circumferential surface of the gear body and forming internal teeth; a planetary gear having external teeth that mesh with the internal teeth; a crankshaft that causes the planetary gear to oscillate by rotating about its axis; and an input-side bracket and an output-side bracket, the input-side bracket being axially disposed on one side of the planetary gear, i.e., the input side, along the axis of the crankshaft; and the output-side bracket being... The output side bracket is axially positioned on the other side of the planetary gear, i.e., the output side. The input side bracket and the output side bracket support the crankshaft so that it can rotate. By oscillating the planetary gear, the planetary gear rotates relative to the internal gear. The internal meshing planetary gear device also includes an input side cover mounted on the input side end of the input side bracket. By contacting the crankshaft with the input side cover, the movement of the crankshaft on the input side is restricted. A micro-dimple forming portion with multiple micro-dimples is formed in the contact portion of the input side cover that contacts the crankshaft.

[0012] The second aspect of this utility model provides an internal meshing planetary gear device according to the aforementioned first aspect, wherein the crankshaft is held in the input side bracket via an input side bearing, the end face of the input side retainer of the input side bearing contacts the input side cover, and a micro-dimple forming portion is formed in the contact portion of the input side cover that contacts both the crankshaft and the input side bearing.

[0013] The third aspect of this utility model provides an internal meshing planetary gear device according to the aforementioned first or second aspect, wherein the maximum depth of each micro-pit in the micro-pit forming portion is 1μm to 15μm.

[0014] A fourth aspect of this invention provides an internal meshing planetary gear device according to the first or second aspect described above, wherein in the micro-dimple forming portion, the area ratio of the plurality of micro-dimples to the area of ​​the micro-dimple forming portion is 5% to 50%.

[0015] The fifth aspect of this utility model provides an internal meshing planetary gear device according to the first or second aspect described above, wherein the crankshaft has a small diameter portion and a journal with an outer diameter larger than the outer diameter of the small diameter portion at its input side end in the axial direction, a shoulder portion is formed between the small diameter portion and the journal, the shoulder portion contacts the input side cover, a shaft hole is formed in the input side cover for the small diameter portion of the crankshaft to pass through, and a micro-dimple forming portion is formed around the shaft hole.

[0016] The sixth aspect of this invention provides an internal meshing planetary gear device according to the first or second aspect described above, wherein the micro-dimple forming portion is formed by shot peening.

[0017] The seventh aspect of this utility model provides an internal meshing planetary gear device according to the aforementioned first or second aspect, wherein the micro-dimple forming portion is formed by laser processing or etching.

[0018] The eighth aspect of this utility model provides an internal meshing planetary gear device according to the aforementioned first aspect, wherein multiple crankshafts are provided, and micro-pit forming portions are formed in the contact portions of the input side cover that contact each of the crankshafts.

[0019] The ninth aspect of this utility model provides an internal meshing planetary gear device according to the aforementioned first or second aspect, the internal meshing planetary gear device further comprising an output side cover mounted on the output side end of the output side bracket, wherein the crankshaft is restricted from moving to the output side by contacting the output side end face of the crankshaft with the output side cover, and a micro-dimple forming portion is formed in the contact portion of the output side cover that contacts the crankshaft.

[0020] Effects of the utility model

[0021] In the input side cover (a cover mounted on the gear carrier end face of an internal meshing planetary gear unit and used to restrict the axial movement of the crankshaft), a micro-dimple forming portion with multiple micro-dimples is formed at least in the contact portion that contacts the crankshaft. This ensures an oil film on the cover and reduces wear. Consequently, it is possible to suppress the shortening of the lifespan of the internal meshing planetary gear unit and to suppress the decrease in efficiency due to increased sliding resistance. Attached Figure Description

[0022] Figure 1 This is a top view of the internal meshing planetary gear device of Embodiment 1.

[0023] Figure 2 It is the internal meshing planetary gear device of embodiment 1. Figure 1 A sectional view along line AA.

[0024] Figure 3 This is a top view of the internal meshing planetary gear device of Embodiment 1 after the transmission gear has been removed from the minor diameter portion of the crankshaft.

[0025] Figure 4 It is the internal meshing planetary gear device of embodiment 1. Figure 3 BB line section view.

[0026] Figure 5This is a plan view of the input side cover of the internal meshing planetary gear device in Embodiment 1, viewed from the output side in the axial direction.

[0027] Figure 6 This is a top view of the internal meshing planetary gear device of Embodiment 2 after the transmission gear has been removed from the minor diameter portion of the crankshaft.

[0028] Figure 7 It is the internal meshing planetary gear device of embodiment 2. Figure 6 CC-line sectional view.

[0029] Figure 8 This is a plan view of the input side cover of the internal meshing planetary gear device in Embodiment 2, viewed from the input side in the axial direction.

[0030] Figure 9 This is a plan view of the input side cover of the internal meshing planetary gear device in Embodiment 3, viewed from the output side in the axial direction.

[0031] Explanation of reference numerals in the attached figures

[0032] 1. 1A. Internal meshing planetary gear assembly; 2. Internal gear; 22. Gear body; 22a. Inner circumferential surface; 2b. Mounting hole; 3. Gear carrier; 31. Input side bracket; 31a. Central hole; 31c. Recess; 31e. Stepped portion; 32. Output side bracket; 32a. Base plate portion; 32b. Shaft portion; 32k. Central hole; 32j. Mounting hole; 4. Planetary gear; 41. First planetary gear; 41a. Central hole; 41b. Insertion hole; 42. Second planetary gear; 42a. Central hole; 42b. Insertion hole; 31b, 32d, 41c, 42c. Crankshaft mounting portion 5. Crankshaft; 51. Shaft body; 51a. Small diameter section; 51b. First journal; 51c. Second journal; 51d. Shoulder; 54. First eccentric section; 55. Second eccentric section; 6. Crankshaft bearing; 62. Retainer; 6A. Input side bearing; 6B. Output side bearing; 7. Drive gear; 8. Pin; 9. 9A. Input side cover; 94. Central hole; 91b. Shaft hole; 91c. Through hole; 92. Cut-off section; 93. Micro-dimple formation section; Ax1. Axis; Ax2. Shaft center; T1. Bracket bolt; B1, B2. Main bearing; A1, A2. Eccentric bearing. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For ease of explanation, only the main components of the internal meshing planetary gear device are shown in the drawings. The gear device shown in the drawings can include a variety of components not shown.

[0034] (Implementation Method 1)

[0035] Figure 1 This is a top view of the internal meshing planetary gear device of Embodiment 1. Figure 2 It is the internal meshing planetary gear device of embodiment 1. Figure 1 A sectional view along line AA. Figure 3 This is a top view of the internal meshing planetary gear device of Embodiment 1 after the transmission gear has been removed from the minor diameter portion of the crankshaft. Figure 4 It is the internal meshing planetary gear device of embodiment 1. Figure 3 A BB-line sectional view. For example... Figure 2 and Figure 3 As shown, the internal meshing planetary gear assembly 1 includes an internal gear 2, a gear carrier 3, planetary gears 4, a crankshaft 5, and a crankshaft bearing 6. The illustrated internal meshing planetary gear assembly 1 is configured such that the internal gear 2 and the gear carrier 3 rotate relative to each other by causing the planetary gear 4 to oscillate and rotate along with the crankshaft 5. The gear carrier 3 has an input-side support 31 and an output-side support 32, which support the crankshaft 5 for rotation via the crankshaft bearing 6.

[0036] Next, further reference Figures 1-4 The structure of the internal meshing planetary gear device 1 according to Embodiment 1 is described below. In the internal meshing planetary gear device 1, the internal gear 2 is configured in a generally cylindrical shape with the axis Ax1 as its central axis. The internal gear 2 has an annular gear body 22 and a plurality of pins 8, and a plurality of pin grooves are formed on the inner circumferential surface 22a of the gear body 22. Each pin groove is arranged to extend axially along the axis Ax1 direction and has a semi-circular cross-sectional shape in a section orthogonal to the axial direction. The pin grooves are arranged at equal intervals along the circumference of the internal gear 2.

[0037] like Figure 2 and Figure 4 As shown, multiple pins 8 are held in multiple pin slots in a rotatable state and form internal teeth. Each pin 8 is cylindrical in shape and extends axially. Moreover, each pin 8 is mounted in a pin slot formed on the inner circumferential surface 22a of the gear body 22.

[0038] The internal gear 2 has a plurality of mounting holes 2b extending axially through it. The mounting holes 2b are arranged at equal intervals along the circumference of the internal gear 2. Each mounting hole 2b can be used when mounting a component (not shown) constituting a joint portion of the robot onto the internal gear 2. For example, when the base of a joint portion constituting the robot is mounted onto the internal gear 2, the internal gear 2 serves as a component on the fixed side of the internal meshing planetary gear assembly 1.

[0039] The gear carrier 3 is configured to clamp the planetary gear 4 axially and is concentrically arranged with the internal gear 2. The gear carrier 3 has an input-side bracket 31 and an output-side bracket 32 ​​that are axially opposite to each other. The input-side bracket 31 is fixed to the output-side bracket 32 ​​using bracket bolts T1.

[0040] The input-side bracket 31 is generally circular and is axially positioned on one side of the planetary gear 4, i.e., the input side. A portion of the input-side bracket 31 is located inside the internal gear 2, and the remaining portion is axially located outside the internal gear 2. A central hole 31a and a crankshaft mounting portion 31b are formed in the input-side bracket 31. The central hole 31a is formed in the central portion of the input-side bracket 31 such that it extends axially through the input-side bracket 31.

[0041] The crankshaft mounting portion 31b is the part for mounting the crankshaft 5. Each crankshaft mounting portion 31b is arranged radially outward from the central hole 31a along the circumference of the gear carrier 3. Each crankshaft mounting portion 31b is formed by a through hole that passes through the input side bracket 31 axially. Moreover, three crankshaft mounting portions 31b are formed on the input side bracket 31.

[0042] The output-side bracket 32 ​​has a generally circular plate-shaped base plate portion 32a and a shaft portion 32b extending from the base plate portion 32a toward the input-side bracket 31. The output-side bracket 32 ​​is axially disposed on the other side of the planetary gear 4, i.e., the output side. A portion of the base plate portion 32a is located inside the internal gear 2, and the remaining portion is axially located outside the internal gear 2.

[0043] The shaft portion 32b extends axially from the end face of the base plate portion 32a on the side of the input-side bracket 31. A plurality of shaft portions 32b are arranged circumferentially along the gear carrier 3. In this embodiment, the output-side bracket 32 ​​is configured to have three shaft portions 32b. A central hole 32k, a crankshaft mounting portion 32d, and a mounting hole 32j are formed in the output-side bracket 32.

[0044] The central hole 32k is formed in the central portion of the output side bracket 32 ​​in such a way that it passes through the base plate portion 32a of the output side bracket 32 ​​along the axial direction.

[0045] The crankshaft mounting portion 32d is the part for mounting the crankshaft 5. Multiple crankshaft mounting portions 32d are formed circumferentially along the outer side of the central hole 32k. Each crankshaft mounting portion 32d is formed by a through hole extending axially through the base plate portion 32a, or by a recessed hole formed by a portion of the base plate portion 32a recessed axially. Each crankshaft mounting portion 32d is positioned corresponding to a crankshaft mounting portion 31b formed on the input-side bracket 31.

[0046] Mounting hole 32j is formed such that the end face of the output-side bracket 32, opposite to the input-side bracket 31, is recessed axially. Mounting hole 32j is used to mount object-side components such as rotating bodies constituting the joint portion of the robot to gear carrier 3. When a rotating body constituting the joint portion of the robot is mounted to gear carrier 3, gear carrier 3 becomes a rotating-side component of internal meshing planetary gear assembly 1. Alternatively, when, for example, the base constituting the joint portion of the robot is mounted to gear carrier 3, a rotating body constituting the joint portion of the robot is mounted to internal gear 2, thereby gear carrier 3 becomes a fixed-side component of internal meshing planetary gear assembly 1 and internal gear 2 becomes a rotating-side component of internal meshing planetary gear assembly 1.

[0047] The internal meshing planetary gear assembly 1 also includes main bearings B1 and B2. Main bearings B1 and B2 are disposed between the outer peripheral surface of the gear carrier 3 and the inner peripheral surface 22a of the internal gear 2. Specifically, main bearing B1 is disposed between the outer peripheral surface of the input-side support 31 and the inner peripheral surface 22a of the internal gear 2, and main bearing B2 is disposed between the outer peripheral surface of the base plate portion 32a of the output-side support 32 and the inner peripheral surface 22a of the internal gear 2. Main bearings B1 and B2 allow relative rotation between the internal gear 2 and the gear carrier 3.

[0048] In crankshaft mounting sections 31b and 32d, crankshaft 5 is rotatably supported on input-side bracket 31 and output-side bracket 32 ​​about axis Ax2. The planetary gear 4 oscillates as crankshaft 5 rotates about axis Ax2. This oscillation causes planetary gear 4 to rotate relative to internal gear 2.

[0049] The internal meshing planetary gear assembly 1 also includes a crankshaft bearing 6, which comprises an input-side bearing 6A and an output-side bearing 6B that allow rotation of the crankshaft 5 relative to the input-side support 31 and the output-side support 32. The input-side bearing 6A and the output-side bearing 6B can be, for example, needle roller bearings. Specifically, the crankshaft 5 is held in the input-side support 31 via the input-side bearing 6A and in the output-side support 32 via the output-side bearing 6B. In this embodiment, as... Figure 1 and Figure 3 As shown, three crankshafts 5 are arranged circumferentially along the gear carrier 3. Furthermore, the number of crankshafts 5 is arbitrary and can be appropriately varied depending on the intended use of the internal meshing planetary gear unit 1.

[0050] The crankshaft 5 has a shaft body 51 extending along the axial direction and a first eccentric portion 54 and a second eccentric portion 55 that are eccentric relative to the shaft body 51.

[0051] The shaft body 51 has a first journal (large diameter portion) 51b, a second journal (large diameter portion) 51c, and a small diameter portion 51a. The small diameter portion 51a is provided at the input side end of the crankshaft 5 in the axial direction and has an outer diameter that is slightly smaller than the outer diameter of the first journal 51b and the outer diameter of the second journal 51c.

[0052] The first journal 51b is located inside the crankshaft mounting portion 31b of the input side bracket 31. An input side bearing 6A is mounted on the outer peripheral surface of the first journal 51b.

[0053] The second journal 51c has the same outer diameter as the first journal 51b. The second journal 51c is located within the crankshaft mounting portion 32d of the output side bracket 32. An output side bearing 6B is mounted on the outer peripheral surface of the second journal 51c.

[0054] The small-diameter portion 51a is axially adjacent to the first journal 51b and extends to the side opposite to the second journal 51c. A shoulder portion 51d is formed between the small-diameter portion 51a and the first journal 51b.

[0055] The first eccentric portion 54 and the second eccentric portion 55 are axially located between the first journal 51b and the second journal 51c. Planetary gears 4 are mounted on the first eccentric portion 54 and the second eccentric portion 55 respectively via eccentric bearings A1 and A2. Eccentric bearings A1 and A2 allow relative rotation between the first eccentric portion 54, the second eccentric portion 55 and the planetary gears 4.

[0056] Planetary gear 4 is located inside internal gear 2 and is axially sandwiched between the base plate portion 32a of output side bracket 32 ​​and input side bracket 31. The internal meshing planetary gear assembly 1 also includes eccentric bearings A1 and A2. Planetary gear 4 has a first planetary gear 41 mounted on a first eccentric portion 54 via eccentric bearing A1 and a second planetary gear 42 mounted on a second eccentric portion 55 via eccentric bearing A2. The first planetary gear 41 and the second planetary gear 42 have outer diameters slightly smaller than the inner diameter of internal gear 2, and multiple external teeth are formed on their outer circumferential surfaces to mesh with the internal teeth formed by pins 8. The number of external teeth formed on the outer circumferential surfaces of each of the first planetary gear 41 and the second planetary gear 42 is slightly less than the number of pins 8. Therefore, the first planetary gear 41 and the second planetary gear 42 can oscillate and rotate in different phases inside internal gear 2, with each external tooth meshing with each pin 8.

[0057] The first planetary gear 41 has a central hole 41a corresponding to the position of the central hole 31a of the input side bracket 31, an insertion hole 41b for inserting the shaft portion 32b, and a crankshaft mounting portion 41c for inserting the first eccentric portion 54.

[0058] The second planetary gear 42 has a central hole 42a corresponding to the position of the central hole 32k of the output side bracket 32, an insertion hole 42b for inserting the shaft portion 32b, and a crankshaft mounting portion 42c for inserting the second eccentric portion 55.

[0059] In addition, in this embodiment, for example, the planetary gear 4 has two planetary gears, a first planetary gear 41 and a second planetary gear 42, but it is not limited to this. It may have only one planetary gear, or it may have three or more planetary gears.

[0060] like Figure 2 As shown, the internal meshing planetary gear assembly 1 also includes a drive gear 7, which transmits driving force to the crankshaft 5 to rotate the crankshaft 5. The drive gear 7 can be configured to have three gears corresponding to the positions of the three crankshafts 5. The drive gear 7 is located axially on the side opposite to the output side bracket 32, separated by the input side bracket 31. The drive gear 7 is mounted on the small diameter portion 51a of the shaft body 51 of the crankshaft 5. A retaining ring mounted on the small diameter portion 51a of the shaft body 51 in a manner that clamps the drive gear 7 from both sides axially restricts the axial movement of the drive gear 7.

[0061] Furthermore, the transmission gear 7 is located axially on the side opposite to the output side support 32, separated by the input side support 31, but is not limited to this. For example, the transmission gear 7 may also be located between the first eccentric portion 54 and the second eccentric portion 55. That is, the configuration of the transmission gear 7 is arbitrary and can be appropriately changed according to the shape of the internal meshing planetary gear device 1.

[0062] The transmission gear 7 has multiple external teeth on its outer circumferential surface. By meshing the input shaft of a motor (not shown) with these external teeth, the driving force (torque) of the motor is transmitted to the crankshaft 5. Then, the first eccentric portion 54 and the second eccentric portion 55 of the crankshaft 5, which receive the driving force from the transmission gear 7, rotate. Correspondingly, the planetary gear 4 oscillates and rotates within the internal gear 2. As a result, the internal gear 2 rotates relative to the gear carrier 3.

[0063] like Figure 2 and Figure 4 As shown, the internal meshing planetary gear device 1 also includes an input side cover 9 mounted axially at the end of the input side bracket 31 on the input side. By bringing the crankshaft 5 into contact with the input side cover 9, the crankshaft 5 is restricted from moving axially toward the input side using the input side cover 9.

[0064] like Figure 3 and Figure 5As shown, the input side cover 9 is formed in a disk shape centered on the axis Ax1. The outer diameter of the input side cover 9 is slightly smaller than the outer diameter of the input side bracket 31. A shaft hole 91b is formed in the input side cover 9, extending axially. The diameter of the shaft hole 91b is set to be slightly larger than the diameter of the small diameter portion 51a of the crankshaft 5, and smaller than the diameter of the first journal 51b. Figure 2 and Figure 4 As shown, the input side cover 9 is configured such that the small diameter portion 51a of the crankshaft 5 passes through the shaft hole 91b, and the shoulder portion 51d between the small diameter portion 51a and the first journal 51b in the crankshaft 5 contacts the input side cover 9. Furthermore, as... Figure 5 As shown, a central hole 94 is formed in the center of the input side cover 9, corresponding to the position of the central hole 31a of the input side bracket 31, and a through hole 91c is formed around the central hole 94, extending axially through the input side cover 9. The bracket bolt T1 passes through the through hole 91c to fix the input side bracket 31 to the output side bracket 32.

[0065] like Figure 2 and Figure 4 As shown in the cross-sectional view, a recess 31c for accommodating the input side cover 9 is formed on the input side end face of the input side bracket 31, which is the end face opposite to the output side bracket 32. A step portion 31e is formed on the bottom surface of the recess 31c. When the input side cover 9 is installed on the input side bracket 31 in a detachable manner from the input side, i.e., from the input side bracket 31, on the side opposite to the planetary gear 4, the input side cover 9 contacts the step portion 31e. The input side cover 9 is installed on the recess 31c of the input side bracket 31 using fixing bolts, but the method of installing the input side cover 9 on the input side bracket 31 is not limited to this.

[0066] By bringing the crankshaft 5 (specifically, the shoulder 51d of the crankshaft 5) into contact with the input side cover 9 mounted on the input side bracket 31, the axial movement of the crankshaft 5 toward the input side is restricted.

[0067] In addition, such as Figure 5 As shown, when viewed from the output side in the axial direction, the input side cover 9 of the internal meshing planetary gear device 1 of Embodiment 1 has a micro-dimple forming portion 93 with multiple micro-dimples formed at the contact portion that contacts the crankshaft 5. This micro-dimple forming portion 93 improves lubricant retention in the internal meshing planetary gear device 1 of Embodiment 1, ensuring an oil film on the input side cover 9 even with a small amount of lubricant. Therefore, compared to the prior art described above, lubricity is improved, suppressing insufficient lubrication. As a result, the risk of wear on the input side cover 9 and the crankshaft 5 is reduced, lowering the risk of efficiency degradation.

[0068] Furthermore, when the crankshaft 5 and the input-side end face of the retainer 62 of the input-side bearing 6A are brought into contact with the input-side cover 9 to restrict the axial movement of the crankshaft 5 and the input-side bearing 6A towards the input side, it is preferable to form a micro-dimple forming portion 93 at the contact portion of the input-side cover 9 that contacts both the crankshaft 5 and the input-side bearing 6A. This ensures a more reliable oil film on the input-side cover 9, suppresses insufficient lubrication, and reduces wear on the input-side cover 9, the crankshaft 5, and the retainer 62 of the input-side bearing 6A. As a result, it is possible to suppress the shortening of the lifespan of the internal meshing planetary gear unit and the decrease in efficiency due to increased sliding resistance.

[0069] The maximum depth of each micro-pit in the micro-pit forming section 93 is preferably 1 μm to 15 μm. This allows for a more reliable oil film to be maintained on the input side cover 9, reducing the risk of wear and efficiency degradation.

[0070] Furthermore, in the micro-pit forming portion 93, the area ratio of the plurality of micro-pits to the area of ​​the micro-pit forming portion 93 is preferably 5% to 50%. As a result, an oil film can be more reliably ensured on the input side cover 9, suppressing the occurrence of insufficient lubrication.

[0071] Furthermore, when the small diameter portion 51a of the crankshaft 5 passes through the shaft hole 91b of the input side cover 9, and the shoulder portion 51d of the crankshaft 5 contacts the input side cover 9, such as Figure 5 As shown, preferably, the micro-dimple forming portion 93 is formed around the shaft hole 91b in the input side cover 9. This allows for a more reliable oil film to be maintained on the input side cover 9, reducing the risk of wear and efficiency degradation.

[0072] Regarding the method of forming the micro-pit formation portion 93, it is preferable to form the micro-pit formation portion 93 using shot peening, a process known in the prior art. Here, forming micro-pits using shot peening helps to solidify the surface of the input side cover 9 and impart residual stress, thereby achieving a further improvement in wear resistance and fatigue strength, resulting in a deformation suppression effect on the input side cover 9. However, the method of forming the micro-pit formation portion 93 is not limited to the shot peening process described above. It can be formed using laser processing or etching processes known in the prior art, or other processing methods known in the prior art. That is, this embodiment is not limited to the method of forming the micro-pit formation portion; any known processing method can be used as long as the micro-pit formation portion described above can be formed.

[0073] Furthermore, in the case where multiple (e.g., three) crankshafts 5 are provided, such as Figure 5As shown, it is preferable that micro-dimple forming portions 93 are formed on the contact portions of the input side cover 9 that contact each of the plurality of crankshafts 5. This allows for more reliable oil film formation on the input side cover 9, reducing the risk of wear and efficiency degradation.

[0074] Furthermore, the internal meshing planetary gear assembly 1 may also include an output side cover mounted on the output side end of the output side bracket 32. By contacting the output side end face of the crankshaft 5 with this output side cover, the axial movement of the crankshaft 5 towards the output side is restricted. Similar to the input side cover 9, a micro-dimple forming portion may be formed at the contact portion of the output side cover that contacts the crankshaft 5, thereby achieving the same effect as the micro-dimple forming portion 93 in the input side cover 9.

[0075] (Implementation Method 2)

[0076] Figure 6 and Figure 7 A schematic structure of the internal meshing planetary gear device 1A according to Embodiment 2 is shown. Figure 6 This is a top view of the internal meshing planetary gear device 1A of Embodiment 2 after the transmission gear has been removed from the minor diameter portion of the crankshaft 5. Figure 7 It is the internal meshing planetary gear device 1A of embodiment 2. Figure 6 CC-line sectional view. Figure 8 This is a plan view of the input side cover 9A in the internal meshing planetary gear device 1A of Embodiment 2, viewed from the input side in the axial direction. The internal meshing planetary gear device 1A of Embodiment 2 differs from the internal meshing planetary gear device 1 of Embodiment 1 only in the structure of the input side cover; otherwise, it is constructed in the same manner as Embodiment 1. Therefore, for structures identical to those in the internal meshing planetary gear device 1 of Embodiment 1, the same reference numerals are used, and correspondingly, repeated descriptions are simplified or omitted.

[0077] like Figure 6 As shown, in Embodiment 2, the input side cover 9A of the internal meshing planetary gear device 1A has a cut-off portion 92 formed at the portion overlapping with the support bolt T1 when viewed along the axial direction. This cut-off portion 92 opens radially outward from the input side cover 9A. By forming the cut-off portion 92 in the input side cover 9A, the weight of the input side cover 9A can be reduced, thereby making the overall internal meshing planetary gear device lighter. Furthermore, in the input side cover 9A, it is not necessary to machine multiple through holes 91c for the support bolt T1 to pass through, as in Embodiment 1. Therefore, it is not necessary to consider the machining risks caused by the through holes 91c being close to each other with other through holes, and the deformation of the input side cover 9A can be reduced. In addition, the tightness of the support bolt T1 can be directly inspected through the cut-off portion 92, which ensures inspection workability and increases design flexibility.

[0078] Furthermore, when the input-side bracket 31 is fixed to the output-side bracket 32 ​​at multiple locations using multiple bracket bolts T1, it is preferable that the input-side cover 9A has a cut-off portion 92 formed in the portion overlapping with each bracket bolt T1 when viewed along the axial direction. In this case, as... Figure 6 and Figure 8 As shown, the input side cover 9A has a trident shape when viewed from the axial input side. This further reduces the weight of the input side cover 9A, further reducing the overall weight of the internal meshing planetary gear unit. Moreover, it also eliminates the need for machining multiple through holes for the support bolt T1 to pass through, further reducing the deformation of the input side cover 9A, further ensuring inspection operability, and further increasing design flexibility.

[0079] (Implementation Method 3)

[0080] Figure 9 This is a plan view of the input side cover 9B in the internal meshing planetary gear device of Embodiment 3, viewed from the output side in the axial direction. The difference between the internal meshing planetary gear device of Embodiment 3 and the internal meshing planetary gear device 1A of Embodiment 2 is that the contact portion of the input side cover 9B that contacts the crankshaft 5 is formed with a micro-dimple forming portion having multiple micro-dimples, similar to Embodiment 1. Otherwise, it is constructed in the same way as the internal meshing planetary gear device 1A of Embodiment 2. Therefore, the following mainly describes the difference from the internal meshing planetary gear device 1A of Embodiment 2, namely the input side cover 9B, and omits repeated descriptions of other structures.

[0081] In the input side cover 9B of the internal meshing planetary gear device in Embodiment 3, as Figure 9 As shown, similarly to Embodiment 2, a cut-off portion 92 is formed. Therefore, similarly to Embodiment 2, it is possible to achieve overall lightweighting of the internal meshing planetary gear device, ensure inspection operability, and increase design flexibility.

[0082] Furthermore, similar to Embodiment 2, when the input-side bracket 31 is fixed to the output-side bracket 32 ​​at multiple locations using multiple bracket bolts T1, it is preferable that the input-side cover 9B has a cut-off portion 92 formed in the portion overlapping with each bracket bolt T1 when viewed along the axial direction. In this case, as... Figure 9 As shown, the input side cover 9B has a trident shape when viewed from the input side in the axial direction. This further reduces the weight of the input side cover 9B, further reducing the overall weight of the internal meshing planetary gear assembly. Moreover, the elimination of the need for machining multiple through holes for the support bolts T1 further reduces the deformation of the input side cover 9B, further ensuring inspection operability and increasing design flexibility.

[0083] In addition, such as Figure 9 As shown, in the input side cover 9B of the internal meshing planetary gear device in Embodiment 3, a micro-dimple forming portion 93 is also formed at the contact portion that contacts the crankshaft 5. Therefore, similar to Embodiment 1, the micro-dimple forming portion 93 can be used to improve lubricant retention, ensuring an oil film on the input side cover 9B even with a small amount of lubricant. Thus, similar to Embodiment 1, lubricity is improved, suppressing the occurrence of insufficient lubrication. As a result, the risk of wear on the input side cover 9B and the crankshaft 5 can be reduced, and the risk of efficiency loss can be reduced.

[0084] Furthermore, in the input side cover 9B of the internal meshing planetary gear device in Embodiment 3, when both the shoulder of the crankshaft 5 and the input side end face of the retainer 62 of the input side bearing 6A are in contact with the input side cover 9B, it is preferable that a micro-dimple forming portion 93 is formed on the contact portion of the input side cover 9B that contacts both the crankshaft 5 and the input side bearing 6A. As a result, similar to Embodiment 1, an oil film can be more reliably maintained on the input side cover 9B, suppressing insufficient lubrication and reducing wear on the input side cover 9B, the crankshaft 5, and the retainer 62 of the input side bearing 6A. Consequently, the shortening of the lifespan of the internal meshing planetary gear device and the decrease in efficiency due to increased sliding resistance can be suppressed.

[0085] Furthermore, in the input side cover 9B of the internal meshing planetary gear device in Embodiment 3, the maximum depth of each micro-pit in the micro-pit forming portion 93 is preferably 1 μm to 15 μm. This allows for more reliable oil film retention on the input side cover 9B, reducing the risk of wear and efficiency degradation.

[0086] Furthermore, in the input side cover 9B of the internal meshing planetary gear device in Embodiment 3, the area ratio of the plurality of micro-pits to the area of ​​the micro-pit forming portion 93 is preferably 5% to 50%. This allows for more reliable oil film preservation on the input side cover 9B, reducing the risk of wear and efficiency degradation.

[0087] Furthermore, when the small diameter portion of the crankshaft 5 passes through the shaft hole 91b of the input side cover 9B, and the shoulder of the crankshaft 5 contacts the input side cover 9B, it is preferable that, Figure 9 As shown, micro-dimple formation 93 is formed around the shaft hole 91b. This allows for more reliable oil film retention on the input side cover 9B, reducing the risk of wear and efficiency degradation.

[0088] Regarding the method for forming the micro-dimple forming portion 93, similar to Embodiment 1, it is preferable to form the micro-dimple forming portion 93 using shot peening, a process known in the prior art. Here, similar to Embodiment 1, forming the micro-dimples using shot peening facilitates surface solidification of the input side cover 9B and imparts residual stress, thereby achieving a further improvement in wear resistance and fatigue strength, resulting in deformation suppression of the input side cover 9B. The method for forming the micro-dimple forming portion 93 is not limited to shot peening; it can also be formed using laser processing or etching, processes known in the prior art.

[0089] Furthermore, in the case where multiple (e.g., three) crankshafts 5 are provided, such as Figure 9 As shown, micro-dimple forming portions 93 are preferably formed on the contact portions of the input side cover 9B that contact each of the multiple crankshafts 5. This allows for more reliable oil film formation on the input side cover 9B, reducing the risk of wear and efficiency degradation.

[0090] Furthermore, similar to Embodiment 1, the internal meshing planetary gear device of Embodiment 3 may also include an output side cover mounted on the output side end of the output side bracket 32. By contacting the output side end face of the crankshaft 5 with the output side cover, the axial movement of the crankshaft 5 towards the output side is restricted. Similar to the input side cover 9B, a micro-dimple forming portion may be formed at the contact portion of the output side cover that contacts the crankshaft 5, thereby achieving the same effect as the micro-dimple forming portion 93 in the input side cover 9B.

[0091] The above is a description of exemplary embodiments of the present invention. The embodiments described above are not limited to those described herein, but can be applied to a wide variety of gear devices. Some of the features described in relation to one embodiment of the various embodiments described above can also be applied to gear devices described in relation to another embodiment.

Claims

1. An internal meshing planetary gear device, characterized in that, This internal meshing planetary gear assembly includes: An internal gear has an annular gear body and multiple pins, which are held in a rotatable state in multiple pin grooves formed on the inner circumferential surface of the gear body and constitute internal teeth. A planetary gear having external teeth that mesh with the internal teeth; A crankshaft that causes the planetary gears to oscillate by rotating about its axis; and An input-side bracket and an output-side bracket are provided. The input-side bracket is axially positioned on one side of the planetary gear, i.e., the input side, along the axis of the crankshaft. The output-side bracket is axially positioned on the other side of the planetary gear, i.e., the output side, and the input-side bracket and the output-side bracket support the crankshaft so that it can rotate. By oscillating the planetary gear, the planetary gear is rotated relative to the internal gear. The internal meshing planetary gear assembly also includes an input side cover mounted on the input side end of the input side bracket. By contacting the crankshaft with the input side cover, the movement of the crankshaft towards the input side is restricted. A micro-dimple forming portion with multiple micro-dimples is formed on the contact portion of the input side cover that contacts the crankshaft.

2. The internal meshing planetary gear device according to claim 1, characterized in that, The crankshaft is held in place by the input-side bracket via an input-side bearing, the input-side end face of the retainer of the input-side bearing contacting the input-side cover. Micro-dimples are formed in the contact portion of the input side cover that contacts both the crankshaft and the input side bearing.

3. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, The maximum depth of each micro-pit in the micro-pit forming part is 1μm~15μm.

4. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, In the micro-pit forming portion, the area ratio of the plurality of micro-pits to the area of ​​the micro-pit forming portion is 5% to 50%.

5. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, The crankshaft has a small-diameter portion and a journal with an outer diameter larger than that of the small-diameter portion at its axial input side end. A shoulder is formed between the small-diameter portion and the journal, and the shoulder contacts the input side cover. A shaft hole is formed in the input side cover for the small diameter portion of the crankshaft to pass through. The micro-dimples are formed around the shaft hole.

6. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, The micro-pit formation is formed by shot peening.

7. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, The micro-pit formation is formed using laser processing or etching.

8. The internal meshing planetary gear device according to claim 1, characterized in that, The crankshaft is provided in multiple ways. The micro-dimple forming portion is formed in the contact portion of the input side cover that contacts each of the crankshafts.

9. The internal meshing planetary gear device according to claim 1 or 2, characterized in that, The internal meshing planetary gear assembly also includes an output side cover mounted on the output side end of the output side bracket. By bringing the output side end face of the crankshaft into contact with the output side cover, the movement of the crankshaft towards the output side is restricted. A micro-dimple is formed at the contact portion of the output side cover that contacts the crankshaft.

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