Eccentric oscillating gear device, assembling method thereof, robot, industrial machine

Abstract

Provided is an eccentric oscillating gear device, a robot, an industrial machine, and a method for assembling an eccentric oscillating gear device. The eccentric oscillating gear device of the present application includes a housing, a first member supported by a first bearing to the housing, a second member supported by a second bearing to the housing, and a fastening portion that fastens the first member and the second member in the axial direction of the housing. The fastening portion includes an internally threaded portion (200) formed in the first member and a fastener (101) having an externally threaded portion (103). The hardness of the fastener is set to be 44 or more on the Rockwell hardness (HRC) scale, and the hardness of the internally threaded portion is lower than the hardness of the fastener.

Description

Technical Field

[0001] This invention relates to an eccentric oscillating gear device, a robot, industrial machinery, and a method for assembling the eccentric oscillating gear device. Background Technology

[0002] Conventionally, examples of eccentric oscillating gear mechanisms include gearboxes (reducers) installed in robots for industrial applications. In such eccentric oscillating gear mechanisms, for example, as described in Patent Document 1, a gear carrier that rotates relative to the target. The gear carrier consists of a retainer and a shaft. The retainer and shaft are fastened by fasteners (bolts). Multiple bolts are arranged around the axis of the gear carrier. The retainer and shaft rotate relative to the housing while being fastened by multiple bolts.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-109264 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, in the prior art, when comparing multiple fasteners (bolts) between the retainer and the shaft, there is a possibility of frictional deviation between the fastening surfaces of the retainer and the shaft. In the event of such frictional deviation, the axial force of the retainer and the shaft becomes unstable. In this case, there is a possibility that the preload cannot be applied evenly to the main bearing.

[0008] The purpose of this invention is to provide an eccentric oscillating gear device, robot, industrial machinery, and assembly method of the eccentric oscillating gear device, which can stabilize the axial force of the retaining member and shaft, improve the stability of fastening, and improve the stability of rotation.

[0009] Solution for solving the problem

[0010] (1) The eccentric oscillating gear device of the present invention solves the above problems through the following solution:

[0011] An eccentric oscillating gear device, comprising:

[0012] case;

[0013] The first component is supported on the housing by means of a first bearing;

[0014] The second component, which is supported on the housing by means of a second bearing; and

[0015] A fastening part that fastens the first component and the second component in the axial direction of the housing.

[0016] The fastening part has an internal thread portion formed on the first component and a fastener having an external thread portion.

[0017] The hardness of the fastener is set to Rockwell hardness (HRC) 44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener.

[0018] With this configuration, the external thread of the aforementioned hardness can plastically deform the rough, minute protrusions of the internal thread during tightening. This increases the contact area between the external and internal threads at the tightening point, reducing deviations in tightening force. Consequently, the axial force of the first and second components can be stabilized. Furthermore, by increasing the hardness of the external thread, individual variations in the surface characteristics after tightening can be minimized. Additionally, the frictional force on the base surface and threaded surface at the tightening point can be stabilized, thus stabilizing the axial force. Therefore, axial force deviations when tightening with the same tightening torque at multiple tightening points can be reduced. This allows for suppression of the upper limit of axial force deviation at the bolt yield point. Moreover, tightening stability enables uniformity of the preload applied to the first and second bearings.

[0019] This improves the stability of rotation in eccentric oscillating gear devices.

[0020] (2) The eccentric oscillating gear device of the present invention is based on (1) above, wherein,

[0021] It can be configured such that the hardness of the internal thread portion is less than the Brinell hardness (HB) 353 (corresponding to HRC38).

[0022] (3) The eccentric oscillating gear device of the present invention is based on (1) above, wherein,

[0023] It can be configured such that the hardness difference between the fastener and the internal thread is greater than the Vickers hardness (HV) 62 (corresponding to HRC6).

[0024] (4) The eccentric oscillating gear device of the present invention is based on (1) above, wherein,

[0025] The relationship between the surface roughness MRa of the externally threaded portion after interlocking and tightening and the surface roughness FRa of the internally threaded portion after tightening can be set as follows:

[0026] The surface roughness FRa of the internal thread portion is in the range of 0.2 to 1.0.

[0027] The ratio RRa = MRa / FRRa is a value in the range of 0.25 to 3.333.

[0028] The units for surface roughness MRa and surface roughness FRa are μm.

[0029] (5) The eccentric oscillating gear device of the present invention is based on (4) above, wherein,

[0030] It can be set as follows: in a rectangular coordinate system with the horizontal axis representing the surface roughness FRa of the internal thread and the vertical axis representing the surface roughness MRa of the external thread / the surface roughness FRa of the internal thread: RRa,

[0031] The relationship between the surface roughness MRa of the externally threaded portion after interlocking and tightening and the surface roughness FRa of the internally threaded portion after tightening is as follows:

[0032] The surface roughness FRa of the internal thread portion is represented by points (FRa, RRa) and the ratio RRa = MRa / FRa, respectively, and these points are set as follows: RRa1 (0.3, 3.333), RRa2 (0.4, 2.500), RRa3 (0.5, 2.000), RRa4 (0.6, 1.667), RRa5 (0.7, 1.429), RRa6 (0.8, 1.250), RRa7 (0.9, 1.111), and RRa8 (1.0, 1.000). The values ​​within the range enclosed by points RRa9(1.0, 0.500), RRa10(0.9, 0.556), RRa12(0.8, 0.250), RRa13(0.7, 0.286), RRa14(0.6, 0.333), RRa15(0.5, 0.400), RRa16(0.4, 0.500), RRa17(0.3, 0.667), RRa18(0.2, 1.000), and RRa19(0.2, 2.500) are:

[0033] The units for surface roughness MRa and surface roughness FRa are μm.

[0034] (6) The eccentric oscillating gear device of the present invention is based on (1) above, wherein,

[0035] The relationship between the surface roughness MRpk of the externally threaded portion after interlocking and tightening and the surface roughness FRpk of the internally threaded portion after tightening can be set as follows:

[0036] The surface roughness FRpk of the internal thread portion is in the range of 0.2 to 0.6.

[0037] The ratio RRpk = MRpk / FRpk is a value in the range of 0.4 to 5.5.

[0038] The units for surface roughness MRpk and surface roughness FRpk are μm.

[0039] (7) The eccentric oscillating gear device of the present invention is based on (6) above, wherein,

[0040] It can be set as follows: in a rectangular coordinate system with the horizontal axis representing the surface roughness FRpk of the internal thread and the vertical axis representing the surface roughness MRpk of the external thread / the surface roughness FRpk:RRpk of the internal thread,

[0041] The relationship between the surface roughness MRpk of the externally threaded portion after interlocking and tightening and the surface roughness FRpk of the internally threaded portion after tightening is as follows:

[0042] The values ​​are set as follows: FRpk represents the surface roughness of the internal thread portion, and RRpk = MRpk / FRpk represents the values ​​at points (FRpk, RRpk), defined as follows: RRpk1 (0.2, 5.500), RRpk2 (0.3, 3.667), RRpk3 (0.4, 2.750), RRpk4 (0.5, 2.200), RRpk5 (0.6, 1.833), RRpk6 (0.6, 1.000), RRpk7 (0.5, 0.400), RRpk8 (0.4, 0.500), RRpk9 (0.3, 0.667), and RRpk10 (0.2, 1.000).

[0043] The units for surface roughness MRpk and surface roughness FRpk are μm.

[0044] (8) The eccentric oscillating gear device of the present invention is based on (1) above, wherein,

[0045] The relationship between the surface roughness MRv of the externally threaded portion after interlocking and tightening and the surface roughness FRv of the internally threaded portion after tightening can be set as follows:

[0046] The surface roughness FRv of the internal thread portion is a value in the range of 0.4 to 1.1.

[0047] The ratio RRv = MRv / FRv is a value in the range of 0.364 to 1.833.

[0048] The units for surface roughness MRv and surface roughness FRv are μm.

[0049] (9) The eccentric oscillating gear device of the present invention is based on (8) above, wherein,

[0050] It can be set as follows: in a rectangular coordinate system with the horizontal axis representing the surface roughness FRv of the internal thread and the vertical axis representing the surface roughness MRv of the external thread / the surface roughness FRv:RRv of the internal thread,

[0051] The relationship between the surface roughness MRv of the externally threaded portion after interlocking and tightening and the surface roughness FRv of the internally threaded portion after tightening is as follows:

[0052] If the surface roughness FRv of the internal thread portion is represented by points (FRv, RRv) and the ratio RRv = MRv / FRv, then the points are set as follows: point RRv1 (0.4, 1.500), point RRv2 (0.5, 1.200), point RRv3 (0.6, 1.833), point RRv4 (0.7, 1.571), point RRv5 (0.8, 1.375), point RRv6 (0.9, 1.222), and point RRv7 (1.0, 1.100). The values ​​within the range enclosed by points RRv8(1.1, 1.000), RRv9(1.1, 0.364), RRv10(1.0, 0.400), RRv11(0.9, 0.444), RRv12(0.8, 0.500), RRv13(0.7, 0.571), RRv14(0.6, 0.667), RRv15(0.5, 0.800), and RRv16(0.4, 1.000) are:

[0053] The units for surface roughness MRv and surface roughness FRv are μm.

[0054] (10) Another technical solution of the present invention, the eccentric oscillating gear device, solves the above problems through the following solution:

[0055] An eccentric oscillating gear device, comprising:

[0056] case;

[0057] An internal gear is disposed on the inner circumference of the housing;

[0058] An external gear that meshes with the internal gear;

[0059] An eccentric body that causes the external gear to oscillate;

[0060] The first component is supported on the housing by means of a first bearing;

[0061] The second component, which is supported on the housing by means of a second bearing; and

[0062] A fastening part that fastens the first component and the second component in the axial direction of the housing.

[0063] The fastening part has an internal thread portion formed on the first component and a fastener having an external thread portion.

[0064] The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener.

[0065] With this configuration, the external thread of the aforementioned hardness can plastically deform the rough, minute protrusions of the internal thread during tightening. This increases the contact area between the external and internal threads at the tightening point, reducing deviations in tightening force. Consequently, the axial force of the first and second components can be stabilized. Simultaneously, by increasing the hardness of the external thread, individual variations in the surface characteristics after tightening can be minimized. Furthermore, the frictional force on the base surface and threaded surface at the tightening point can be stabilized. Therefore, axial force stability is achieved. Consequently, axial force deviations when tightening with the same tightening torque at multiple tightening points can be reduced. Thus, the upper limit of axial force deviation can be suppressed based on the bolt yield point. Moreover, tightening stability allows for uniform preload applied to the first and second bearings.

[0066] This improves the stability of rotation in eccentric oscillating gear devices.

[0067] (11) Another technical solution of the present invention provides a robot that solves the above problems through the following solution:

[0068] A robot that possesses:

[0069] Multiple components, including an arm that is connected to be freely movable;

[0070] A connecting portion that connects a plurality of said components, including the arm portion, to be rotatable; and

[0071] An eccentric oscillating gear device is mounted on the connecting part.

[0072] The eccentric oscillating gear device includes:

[0073] case;

[0074] The first component is supported on the housing by means of a first bearing;

[0075] The second component, which is supported on the housing by means of a second bearing; and

[0076] A fastening part that fastens the first component and the second component in the axial direction of the housing.

[0077] The fastening part has an internal thread portion formed on the first component and a fastener having an external thread portion.

[0078] The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener.

[0079] With this configuration, the external thread of the aforementioned hardness can plastically deform the rough, minute protrusions of the internal thread during tightening. This increases the contact area between the external and internal threads at the tightening point, reducing deviations in tightening force. Consequently, the axial force of the first and second components can be stabilized. Furthermore, by increasing the hardness of the external thread, individual variations in the surface characteristics after tightening can be minimized. Additionally, the frictional force on the base surface and threaded surface at the tightening point can be stabilized. Therefore, axial force stability is achieved. Consequently, tightening can be performed at multiple tightening points using the same tightening torque. This reduces axial force deviations during tightening at the tightening points. Thus, the upper limit of axial force deviation can be suppressed based on the bolt yield point. Moreover, tightening stability allows for uniform preload applied to the first and second bearings.

[0080] This improves the fastening between the relatively rotating first and second components and enhances rotational stability. Consequently, it allows for improved rotational stabilization in the eccentric oscillating gear mechanism. Furthermore, by stabilizing the axial force and ensuring rigidity stability of the eccentric oscillating gear mechanism under torque, the robot's positional and trajectory accuracy can be maintained at a high level.

[0081] (12) Another technical solution of the present invention provides an industrial machine that solves the above problems through the following solution:

[0082] An industrial machine that has:

[0083] Multiple components, which are interconnected;

[0084] A connecting part that connects the plurality of said components to allow for free rotation; and

[0085] An eccentric oscillating gear device is mounted on the connecting part.

[0086] The eccentric oscillating gear device includes:

[0087] case;

[0088] The first component is supported on the housing by means of a first bearing;

[0089] The second component, which is supported on the housing by means of a second bearing; and

[0090] A fastening part that fastens the first component and the second component in the axial direction of the housing.

[0091] The fastening part includes an internal thread portion formed on the first member and a fastener having an external thread portion.

[0092] The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener.

[0093] With this configuration, the external thread of the aforementioned hardness can plastically deform the rough, minute protrusions of the internal thread during tightening. This increases the contact area between the external and internal threads at the tightening point, reducing deviations in tightening force. Consequently, the axial force of the first and second components can be stabilized. Furthermore, by increasing the hardness of the external thread, individual variations in the surface characteristics after tightening can be minimized. Additionally, the frictional forces on the base surface and threaded surface at the tightening point can be stabilized. Therefore, the axial force at the tightening point can be stabilized. Thus, tightening can be performed at multiple tightening points using the same tightening torque. This reduces axial force deviations during tightening at the tightening points. Consequently, the upper limit of axial force deviation can be suppressed based on the bolt yield point. Moreover, tightening stabilization allows for uniform preload applied to the first and second bearings.

[0094] This improves the fastening between the relatively rotating first and second components and enhances rotational stability. Consequently, it allows for improved rotational stabilization in eccentric oscillating gear mechanisms. Furthermore, by stabilizing the axial force, the rigidity of the eccentric oscillating gear mechanism under torque is stabilized, enabling the positional and trajectory accuracy of industrial machinery to remain at a high level.

[0095] (13) Another technical solution of the present invention provides an assembly method for an eccentric oscillating gear device that solves the above problems through the following solution:

[0096] A method for assembling an eccentric oscillating gear device, wherein,

[0097] The eccentric oscillating gear device includes:

[0098] case;

[0099] The first component is supported on the housing by means of a first bearing;

[0100] The second component, which is supported on the housing by means of a second bearing; and

[0101] A fastening part that fastens the first component and the second component in the axial direction of the housing.

[0102] In the assembly method of the eccentric oscillating gear device,

[0103] During the assembly of the eccentric oscillating gear assembly, when fastening the first component and the second component using the fastening part, a preload is applied to the first bearing and the second bearing.

[0104] The fastening part has an internal thread portion formed on the first component and a fastener having an external thread portion.

[0105] The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener.

[0106] With this configuration, during tightening, the external thread with the aforementioned hardness can plastically deform the rough, minute protrusions of the internal thread during tightening. This increases the contact area between the external and internal threads at the tightening point, reducing deviations in tightening force. Consequently, the axial force of the first and second components can be stabilized. Simultaneously, by increasing the hardness of the external thread, individual variations in the surface characteristics after tightening can be minimized. Furthermore, the frictional force on the base surface and threaded surface at the tightening point can be stabilized, thus stabilizing the axial force. Therefore, tightening can be performed at multiple tightening points using the same tightening torque. This reduces axial force deviations during tightening at the tightening points. Thus, the upper limit of axial force deviation can be suppressed based on the bolt yield point. Moreover, tightening stabilization allows for uniform preload applied to the first and second bearings.

[0107] This improves the fastening between the relatively rotating first and second components and enhances rotational stability. Consequently, rotational stabilization in the eccentric oscillating gear mechanism allows for increased torque density. Furthermore, by stabilizing the axial force, the rigidity of the eccentric oscillating gear mechanism under torque is stabilized, thus stabilizing its lifespan.

[0108] The effects of the invention

[0109] According to the present invention, the following effects can be achieved: an eccentric oscillating gear device, a robot, industrial machinery, and an assembly method for the eccentric oscillating gear device can be provided, which can reduce force deviation, stabilize the axial force of the shaft and the retaining member, and uniformly apply preload to the main bearing. Attached Figure Description

[0110] Figure 1 This is a cross-sectional view showing the first embodiment of the eccentric oscillating gear device of the present invention.

[0111] Figure 2 It is along Figure 1A sectional view along line II-II.

[0112] Figure 3 This is a cross-sectional view showing the internal thread portion of the fastening part in the first embodiment of the eccentric oscillating gear device of the present invention.

[0113] Figure 4 This is a cross-sectional view showing the external thread portion of the fastening part in the first embodiment of the eccentric oscillating gear device of the present invention.

[0114] Figure 5 This is a cross-sectional view showing the second embodiment of the eccentric oscillating gear device of the present invention.

[0115] Figure 6 This is a cross-sectional view showing the third embodiment of the robot of the present invention.

[0116] Figure 7 This is a graph showing the relationship between the surface roughness FRa (μm) of the internal thread portion and the surface roughness MRa (μm) of the external thread portion / the surface roughness FRa (μm) of the internal thread portion: RRa in the eccentric oscillating gear device of the present invention.

[0117] Figure 8 This is a graph showing the relationship between the surface roughness FRa (μm) of the internal thread portion and the surface roughness MRa (μm) of the external thread portion / the surface roughness FRa (μm) of the internal thread portion: RRa in the eccentric oscillating gear device of the present invention.

[0118] Figure 9 This is a graph showing the relationship between the surface roughness FRpk (μm) of the internal thread portion and the surface roughness MRpk (μm) of the external thread portion / the surface roughness FRpk (μm) of the internal thread portion: RRpk in the eccentric oscillating gear device of the present invention.

[0119] Figure 10 This is a graph showing the relationship between the surface roughness FRpk (μm) of the internal thread portion and the surface roughness MRpk (μm) of the external thread portion / the surface roughness FRpk (μm) of the internal thread portion: RRpk in the eccentric oscillating gear device of the present invention.

[0120] Figure 11 This is a graph showing the relationship between the surface roughness FRv (μm) of the internal thread portion and the surface roughness MRv (μm) of the external thread portion in the eccentric oscillating gear device of the present invention: RRv / internal thread portion surface roughness FRv (μm).

[0121] Figure 12This is a graph showing the relationship between the surface roughness FRv (μm) of the internal thread portion and the surface roughness MRv (μm) of the external thread portion in the eccentric swing type gear device of the present invention: RRv / surface roughness FRv (μm) of the internal thread portion.

[0122] Explanation of Reference Numerals

[0123] 1. Eccentric swing type gear device (reducer); 2. Outer cylinder (housing); 4. Gear holder portion; 6A. First bearing (main bearing); 6B. Second bearing (main bearing); 10A. Crankshaft (eccentric body); 41. First gear holder (first member, shaft); 42. Second gear holder (second member, retainer); 44. Support portion (shaft portion); 100. Fastening portion; 101, 151. Bolts (fasteners); 103. External thread portion; 105. Base surface; 110, 210. Thread teeth; 110b, 210b. Thread root; 111, 201. Pressing side tooth flank (Japanese: Oshi furanku men); 112, 202. Rear side tooth flank (Japanese: Ato furanku men); 150. Mounting and fastening portion; 200, 250. Internal thread portion; R. Robot; 330L, 330U, 330S. Connecting portion. Detailed Description of the Embodiment

[0124] <First Embodiment>

[0125] Hereinafter, a first embodiment of the eccentric swing type gear device of the present invention will be described based on the drawings.

[0126] Figure 1 This is a cross-sectional view showing the eccentric swing type gear device in this embodiment. Figure 2 It is Figure 1 a cross-sectional view taken along line II-II. In Figure 1 and Figure 2 , the reference numeral 1 denotes an eccentric swing type gear device.

[0127] [Eccentric Swing Type Gear Device]

[0128] As Figure 1 , Figure 2 shown, the eccentric swing type gear device 1 of this embodiment is a so-called solid shaft reducer (transmission) with a solid input shaft 8.

[0129] The eccentric swing type gear device (reducer) 1 includes a housing 30 and a reduction mechanism portion 40.

[0130] The housing 30 includes a main body portion 32 and a flange portion 34. The flange portion 34 has a shape that protrudes radially outward from the main body portion 32. In the description of the first embodiment, the direction along the axis C1 of the main body portion 32 is simply referred to as the axial direction, the direction intersecting the axis C1 from the axial view is referred to as the radial direction, and the direction of rotation around the axis C1 is referred to as the circumferential direction. In addition, in the eccentric oscillating gear device 1, the side connected to the drive source is referred to as the input side, and the side connected to the mechanism portion such as the arm that receives the output of the eccentric oscillating gear device 1 is referred to as the output side. The drive source is an example of the first component, and the mechanism portion such as the arm is an example of the second component. The eccentric oscillating gear device 1 transmits driving force by changing the rotational speed between the first component and the second component at a predetermined rotational speed ratio.

[0131] The main body 32 is formed in a cylindrical shape along axis C1. As an example of the first cylindrical part, the main body 32 has an input side opening in the direction of axis C1. The reduction gear 40 is rotatably housed in the opening of the main body 32. A flange 34 is integrally formed on the main body 32. Multiple (e.g., three) transmission gears 20 are exposed to the outside in the eccentric oscillating gear device 1. Rotation from the motor is input to the eccentric oscillating gear device 1 via the transmission gears 20.

[0132] A flange 34 is provided on the outer periphery of the housing 30. The flange 34 has a through hole 35 extending axially through it. Through holes 35 are provided at arbitrary intervals in the circumferential direction of the flange 34. The through holes 35 are fastening holes through which fastening members such as bolts for fastening the eccentric oscillating gear device 1 and the robot R (described later) pass. The through holes 35 have an internal thread (not shown). The fastening member is screwed into the internal thread. The through holes 35 and the fastening member constitute the mounting fastening part (described later).

[0133] The eccentric oscillating gear device 1 rotates the crankshaft (eccentric body) 10A by rotating the input shaft 8 corresponding to the input gear 20b. The eccentric oscillating gear device 1 is configured such that the oscillating gear 14 and the oscillating gear 16 oscillate and rotate in conjunction with the eccentric portions 10a and 10b of the crankshaft 10A, thereby obtaining the output rotation obtained by reducing the input rotation speed.

[0134] The eccentric oscillating gear device 1 includes: an outer cylinder (housing) 2, which corresponds to the main body 32 (first cylinder); a gear frame 4, which is an example of the second cylinder; an input shaft 8; a plurality of (e.g., 3) crankshafts 10A; a first oscillating gear 14; a second oscillating gear 16; and a plurality of (e.g., 3) transmission gears 20.

[0135] The outer cylinder 2 has a generally cylindrical shape. The outer cylinder 2 forms the outer surface of the eccentric oscillating gear device 1. Multiple pin grooves 2b are formed on the inner circumferential surface of the outer cylinder 2. Each pin groove 2b is arranged to extend axially along the outer cylinder 2. Each pin groove 2b has a semi-circular cross-sectional shape in a section orthogonal to the axial direction. These pin grooves 2b are arranged at equal intervals along the circumferential direction on the inner circumferential surface of the outer cylinder 2.

[0136] The outer cylinder 2 has multiple internal toothed pins (internal teeth) 3. Each internal toothed pin 3 is installed in a pin groove 2b.

[0137] Specifically, each internal toothed pin 3 is embedded in a corresponding pin groove 2b, arranged in a posture extending axially in the outer cylinder 2. Thus, the plurality of internal toothed pins 3 are arranged at equal intervals along the circumference of the outer cylinder 2. The first external tooth 14a of the first oscillating gear 14 and the second external tooth 16a of the second oscillating gear 16 mesh with these internal toothed pins 3.

[0138] The gear carrier 4 and the outer cylinder 2 are arranged coaxially. The gear carrier 4 is housed inside the outer cylinder 2. The gear carrier 4 rotates relative to the outer cylinder 2 (housing 30) about the same axis.

[0139] Specifically, the gear carrier 4 is disposed radially inside the outer cylinder 2. In this state, the gear carrier 4 is supported by the main bearing 6 and can rotate relative to the outer cylinder 2. The gear carrier 4 is composed of a first gear carrier (first member; shaft) 41 and a second gear carrier (second member; retainer) 42, which are separated in the direction of axis C1. The first gear carrier (first member; shaft) 41 is disposed on the first direction side in the direction of axis C1. The second gear carrier (second member; retainer) 42 is disposed on the second direction side in the direction of axis C1.

[0140] Furthermore, the first direction side corresponds to the previously described output side. The second direction side corresponds to the previously described input side.

[0141] The main bearing 6 is a ball bearing with spherical rolling elements. A pair of main bearings 6 are arranged axially separated from each other. However, the structure of the main bearing 6 is not limited to this embodiment. Various types of bearings, such as roller bearings, especially tapered roller bearings with approximately frustum-shaped rolling elements, and sliding bearings, can be used as the main bearing 6.

[0142] The first gear carrier 41 includes a circular plate-shaped base plate portion 43 and a plurality of (for example, three in this embodiment) support portions (shaft portions) 44 protruding in a second direction from the end of the base plate portion 43 on the second direction side. In this embodiment, the base plate portion 43 and the support portions 44 are integrally formed.

[0143] A first bearing housing portion 41h is formed on the outer peripheral surface 41a of the first gear carrier 41. The inner ring 6Aa of the first bearing (main bearing) 6A is fitted into the first bearing housing portion 41h. Additionally, a first bearing housing portion 2h is formed on the inner peripheral surface of the outer cylinder 2 (housing 30) near the first direction. The outer ring 6Ab of the first bearing 6A is fitted into this first bearing housing portion 2h.

[0144] The support portion 44 of the first gear carrier 41 is formed as a column extending along the axis C1. The support portion 44 is triangular in shape when viewed from the axis C1. Each support portion 44 is arranged circumferentially between the mounting holes 4e of the base plate portion 43 (described later). That is, each support portion 44 is arranged at equal intervals circumferentially toward the second direction side of the base plate portion 43. The pitch circle diameter of each support portion 44 is approximately the same as the pitch circle diameter of the mounting hole 4e.

[0145] The front end portion 44a of the support portion 44 is formed flat. An internal thread portion 200, serving as a fastening portion 100, is formed on the front end portion 44a of the support portion 44. In this embodiment, two fastening portions 100 are formed for each support portion 44. Three or more fastening portions 100 may also be formed. In this embodiment, the number of fastening portions 100 is not limited to these examples. Multiple fastening portions 100 are located on the same circle centered on axis C1. Furthermore, in each of the three support portions 44, the fastening portions 100 are also located on the same circle centered on axis C1. That is, all six fastening portions 100 are located on the same circle centered on axis C1. The pitch circle diameters of the six fastening portions 100 are the same, centered on axis C1.

[0146] The internal thread portion 200 extends from the front end portion 44a of the support portion 44 toward the first direction. The bolt (fastener) 101 is fastened to the internal thread portion 200, thereby assembling the first gear carrier 41 and the second gear carrier 42 into one unit.

[0147] The second gear carrier 42 is formed in the shape of a circular plate. The first end 42a of the second gear carrier 42 on the first direction side abuts against the front end 44a of the support portion 44. Thus, the second gear carrier 42 is positioned relative to the first gear carrier 41. Therefore, a gap with the same height as the support portion 44 is formed between the base plate portion 43 of the first gear carrier 41 and the second gear carrier 42. The housing 30 surrounds the area around this gap, thereby forming a swing gear housing portion for housing the swing gear 14 and the swing gear 16.

[0148] A second bearing housing portion 42g is formed on the outer peripheral surface 42c of the second gear carrier 42. The inner ring 6Ba of the second bearing (main bearing) 6B is fitted into the second bearing housing portion 42g. Additionally, a second bearing housing portion 2g is formed on the inner peripheral surface of the outer cylinder 2 (housing 30). The second bearing housing portion 2g is located in a second direction. The outer ring 6Bb of the second bearing 6B is fitted into this second bearing housing portion 2g.

[0149] The first end 42a of the second gear carrier 42 is generally flat. A fitting hole 45, extending through the thickness of the second gear carrier 42, is formed on the second gear carrier 42 at a position corresponding to the internal thread 200. A bolt (fastener) 101 is inserted into the fitting hole 45 from the second direction side of the second gear carrier 42. The bolt 101 is fastened to the internal thread 200 of the support portion 44. Thus, the first gear carrier 41 and the second gear carrier 42 are combined as a single unit. The bolt 101 and the internal thread 200 constitute the fastening portion 100. The fastening portion 100 will be discussed subsequently.

[0150] With the bolt 101 fastened to the internal thread 200, the shank 102 of the bolt 101 engages with the internal thread 200 of the support portion 44 and the engagement hole 45 of the second gear carrier 42. That is, the shank 102 of the bolt 101 is positioned across the first gear carrier 41 and the second gear carrier 42.

[0151] A countersunk hole 45a, which connects to a fitting hole 45, is formed at the second end 42b of the second gear carrier 42 facing the second direction. The head 104 of the bolt 101 is inserted into the countersunk hole 45a. This reduces the protrusion height of the head 104 of the bolt 101 from the second end 42b of the second gear carrier 42. The base surface 105 of the head 104 of the tightened bolt 101 contacts the bottom surface 45b of the countersunk hole 45a.

[0152] The input shaft 8 functions as an input section for supplying driving force to a drive motor (not shown). The input shaft 8 is inserted into a through hole in the second gear carrier (end plate portion) 42. The input shaft 8 is also inserted into a through hole 4d in the base plate portion 43. The input shaft 8 is arranged such that its axis is aligned with the axes of the outer cylinder 2 and the gear carrier portion 4. The input shaft 8 rotates about its axis. An input gear 8a is provided on the outer peripheral surface of the front end of the input shaft 8.

[0153] Three crankshafts 10A are arranged at equal intervals around the input shaft 8 inside the outer cylinder 2 (see reference). Figure 2 Each crankshaft 10A is supported by a pair of crankshaft bearings 12a and 12b, allowing it to rotate about an axis relative to the gear carrier 4 (see reference). Figure 1 ).

[0154] Each crankshaft 10A has a shaft body 12c and eccentric portions 10a and 10b integrally formed with the shaft body 12c.

[0155] A fitting portion 10c is provided at one end of the crankshaft 10A. A transmission gear 20 is mounted on the fitting portion 10c. One end of the crankshaft 10A is positioned axially outward from the mounting hole 4e of the base plate portion 43. Furthermore, the eccentric oscillating gear device 1 of this embodiment is not limited to... Figure 1 The example shown. In an eccentric oscillating gear device, for example, the crankshaft 10A may be configured in the opposite direction axially. In this case, the mating part 10c is positioned axially outward from the mounting hole 4g ​​of the second gear carrier (end plate part) 42.

[0156] The first oscillating gear 14 is disposed in the closed space inside the outer cylinder 2. The first oscillating gear 14 is mounted on the first eccentric portion 10a of each crankshaft 10A by means of the first roller bearing 18a. When the first eccentric portion 10a rotates eccentrically with the rotation of each crankshaft 10A, the first oscillating gear 14 oscillates and rotates while meshing with the internal gear pin 3 in conjunction with the eccentric rotation of the first eccentric portion 10a.

[0157] The second oscillating gear 16 is disposed in the closed space inside the outer cylinder 2. The second oscillating gear 16 is mounted on the second eccentric portion 10b of each crankshaft 10A by means of the second roller bearing 18b. The first oscillating gear 14 and the second oscillating gear 16 are arranged axially in a manner corresponding to the configuration of the first eccentric portion 10a and the second eccentric portion 10b. When the second eccentric portion 10b rotates eccentrically with the rotation of each crankshaft 10A, the second oscillating gear 16 oscillates and rotates in conjunction with the eccentric rotation of the second eccentric portion 10b, while meshing with the internal gear pin 3.

[0158] Each transmission gear 20 transmits the rotation of the input gear 8a to the corresponding crankshaft 10A. Each transmission gear 20 is fitted onto the corresponding engagement portion 10c of the crankshaft 10A. Each transmission gear 20 rotates integrally with the crankshaft 10A about an axis that is the same as the axis of rotation of the crankshaft 10A. Each transmission gear 20 has external teeth 20a that mesh with the input gear 8a.

[0159] [Fastening Part]

[0160] The fastening part 100 has an internal thread 200 and a bolt 101.

[0161] Bolt 101 includes a shank 102, an externally threaded portion 103 formed in the shank 102, and a head 104 formed in the portion of the shank 102 located on the second direction side. The head 104 is coaxially disposed with the shank 102. The head 104 is enlarged in diameter compared to the shank 102. The hardness of the internally threaded portion 200 is lower than that of the bolt 101.

[0162] The internal thread portion 200 is described below.

[0163] Figure 3 This is a cross-sectional view showing the internal thread portion of the fastener, including the axis of the thread teeth, in this embodiment. Note that, for ease of explanation, some parts are not accurately shown with dimensions, etc.

[0164] The thread tooth 210 in the internal thread portion 200 has a push-side tooth surface 201, a rear tooth surface 202, and a thread root 210b sandwiched between the push-side tooth surface 201 and the rear tooth surface 202.

[0165] First, when tightening the internal thread portion 200 and the bolt 101, the direction in which the internal thread portion 200 and the bolt 101 approach each other along the axis C5 of the internal thread portion 200 and the bolt 101 is defined as the approach direction. The approach direction is along... Figure 1 The direction of axis C1 in the middle. In the internal thread section 200, in Figure 3 The second direction from left to right becomes the approach direction. Furthermore, in... Figure 3 In the diagram, arrow S1, pointing from right to left, indicates the direction of travel of bolt 101 during tightening. Therefore, from the perspective of bolt 101, the approach direction becomes... Figure 3 The first direction is from right to left. If viewed from bolt 101, the approach direction becomes... Figure 3 The direction of travel from right to left is S1.

[0166] The angle of the thread tooth 210 is approximately 60 degrees. The angle of the thread tooth 210 is not limited to this angle. The push-side tooth flank 201 and the rear tooth flank 202 are formed on the upper part of the thread tooth 210 near the front end 210a. The upper part of the thread tooth 210 refers to the portion of the thread tooth 210 that is away from the thread root 210b. The upper part of the thread tooth 210 is the portion of the thread tooth 210 near the front end 210a. The upper part of the thread tooth 210 is the portion near the axis C5 of the internal thread portion 200.

[0167] The push-side tooth flank 201 and the back-side tooth flank 202 are formed such that the threaded tooth 210 is sandwiched in the middle and is opposite to each other along the axis C5. The push-side tooth flank 201 is formed on the opposite side of the threaded tooth 210 along the axis C5 relative to the back-side tooth flank 202. The push-side tooth flank 201 is formed at a position of the threaded tooth 210 facing a first direction. The back-side tooth flank 202 is formed at a position of the threaded tooth 210 facing a second direction.

[0168] The external thread portion 103 of bolt 101 will be described.

[0169] Figure 4 This is a cross-sectional view showing the external thread portion of the fastening part, including the axis of the thread teeth, in this embodiment. Wherein, in this... Figure 4In order to make the explanation easier to understand, there are also parts that are not accurately represented by their respective dimensions.

[0170] The thread tooth 110 of the external thread portion 103 has a push-side tooth lateral surface 111, a rear tooth lateral surface 112, and a thread root 110b sandwiched between the push-side tooth lateral surface 111 and the rear tooth lateral surface 112.

[0171] First, in the external thread portion 103, as described above, the first direction from right to left becomes the approach direction. Therefore, the approach direction of the external thread portion 103 corresponds to the approach direction as viewed from the bolt 101.

[0172] The angle of thread 110 is approximately 60 degrees. The pitch of thread 110 is equivalent to the distance measured parallel to axis C5 between adjacent thread roots 110b. The upper part of thread 110 refers to the portion of thread 110 that is furthest from the thread root 110b. The upper part of thread 110 is the portion of thread 110 near the front end 110a. The upper part of thread 110 is the portion near axis C5 of the external thread portion 103.

[0173] The push-side tooth facet 111 and the rear tooth facet 112 are formed such that the threaded tooth 110 is sandwiched in the middle and is opposite to each other along the axis C5. The push-side tooth facet 111 is formed on the opposite side of the threaded tooth 110 along the axis C5 relative to the rear tooth facet 112. The push-side tooth facet 111 is formed on the threaded tooth 110 facing the base surface 105 (see reference). Figure 1 The push-side tooth lateral surface 111 is formed on the portion of the thread tooth 110 facing the second direction. The rear tooth lateral surface 112 is formed on the portion of the thread tooth 110 facing the first direction.

[0174] When the bolt 101 is screwed into the internal thread portion 200, the push-side tooth 111 of the thread tooth 110 of the external thread portion 103 pushes the push-side tooth 201 of the thread tooth 210 of the internal thread portion 200.

[0175] At this time, due to the force from the bolt 101, the thread 210 deforms towards the base surface 105 of the bolt 101 (right side of the figure). As a result, the thread 210 undergoes elastic deformation.

[0176] Similarly, due to the force from the internal thread 200, the thread tooth 110 deforms in the direction of travel S1 (left side of the figure) of the bolt 101. As a result, the thread tooth 110 undergoes elastic deformation.

[0177] In the fastening part 100, if the hardness of the internal thread part 200 and the hardness of the external thread part 103 are compared, the hardness of the internal thread part 200 is lower than that of the external thread part 103.

[0178] The hardness of bolt 101 is Rockwell hardness (HRC) 44 or higher. The hardness of bolt 101 can be Rockwell hardness (HRC) 44 to (HRC) 100. More preferably, the hardness of bolt 101 can be Rockwell hardness (HRC) 44 to (HRC) 55. Alternatively, the hardness of bolt 101 can be Rockwell hardness (HRC) 44 to (HRC) 50.

[0179] In other words, the hardness of bolt 101 is Brinell hardness (HB) 409 or higher. Alternatively, the hardness of bolt 101 can be Brinell hardness (HB) 409 to (HB) 475 (HRC50).

[0180] In other words, the hardness of bolt 101 is Vickers hardness (HV) 434 or higher. Alternatively, the hardness of bolt 101 can be Vickers hardness (HV) 434 to (HV) 513.

[0181] On the other hand, the first gear carrier (first component; shaft) 41, the base plate portion 43, and the shaft portion 44 are made of the same raw material. Specifically, the hardness of the internal thread portion 200 formed in the shaft portion 44 is less than the Brinell hardness (HB) 353 (corresponding to HRC38).

[0182] In other words, the hardness of the internal thread 200 is less than the Rockwell hardness (HRC) 38.

[0183] In other words, the hardness of the internal thread 200 is less than the Vickers hardness (HV) 372 (corresponding to HRC38).

[0184] Furthermore, in the fastening portion 100, the hardness difference between the bolt 101 and the internal thread portion 200 is greater than the Vickers hardness (HV) 62 (corresponding to HRC 6). In other words, the hardness difference between the bolt 101 and the internal thread portion 200 is greater than the Brinell hardness (HB) 56 (corresponding to HRC 6). In other words, the hardness difference between the bolt 101 and the internal thread portion 200 is greater than the Rockwell hardness (HRC) 6.

[0185] In the fastening portion 100, due to the fastening force during fastening, the thread 110 of the harder external thread portion 103 comes into contact with the thread 210 of the softer internal thread portion 200. As a result, the surface of the thread 210 of the softer internal thread portion 200 changes. Specifically, due to the fastening force, the shape of the push-side tooth flank 111 of the harder external thread portion 103 is transferred to the push-side tooth flank 201 of the softer internal thread portion 200. That is, the rough tooth portion formed on the push-side tooth flank 201 is flattened due to the applied fastening force. In other words, the rough micro-protrusions of the push-side tooth flank 201 are plastically deformed due to the applied fastening force. Therefore, the coefficient of friction of the push-side tooth flank 201 decreases, and the axial force stabilizes.

[0186] Therefore, the surface roughness (surface roughness) of the push-side tooth flank 201 of the thread tooth 210 of the internal thread portion 200 is within the predetermined range mentioned above. The change in surface roughness of the push-side tooth flank 201 in the thread tooth 210 of the internal thread portion 200 can be used as an index of the fastening state at the fastening portion 100.

[0187] According to the eccentric oscillating gear device 1 of this embodiment, the first gear carrier (shaft) 41 and the second gear carrier (retainer) 42 are fastened together according to the above-described structure. As a result, the threads 110 and 210 of the bolt (fastener) 101 (external thread 103) and the support portion 44 (internal thread 200) respectively come into contact with each other. At this time, due to the difference in hardness, the surface shape of the thread 110 is transferred onto the surface shape of the thread 210. Therefore, the deviation of frictional force at the contact surfaces of the threads 110 and 210 of the plurality of fastening portions 100 can be reduced. Thus, the axial force of the first gear carrier 41 and the second gear carrier 42 can be stabilized. In the eccentric oscillating gear device 1 of this embodiment, a preload can be uniformly applied to the main bearing 6.

[0188] Furthermore, it is possible to set the same tightening torque for multiple fasteners 100, thereby reducing axial force deviation during tightening at multiple fasteners 100. This allows for suppression of the upper limit of axial force deviation at the bolt yield point. Consequently, the torque density used to achieve the increased axial force can be improved.

[0189] Furthermore, it is possible to uniformly apply preload to the tapered bearings of crankshaft bearings 12a and 12b used in crankshaft (eccentric body) 10A. As a result, the rotational stability of the eccentric oscillating gear device 1 can be improved, and the service life of the eccentric oscillating gear device 1 can be extended.

[0190] Simultaneously, due to the hardness difference between thread 110 and thread 210, the surface shape of the thread 110 of the external thread portion 103 can be transferred to the thread 210 of the internal thread portion 200 provided on the first gear carrier (shaft) 41. Furthermore, by setting the hardness difference between thread 110 and thread 210 as described above, the transfer of the surface shape of thread 110 to thread 210 can be facilitated. Therefore, in the fastening portion 100, the contact area between the thread 110 of the external thread portion 103 and the thread 210 on the internal thread portion 200 side can be increased. Consequently, the axial force of the fastening portion 100 can be stabilized.

[0191] In the fastening part 100, the deviation of frictional force at the contact surface between the bolt 101 and the first gear carrier (shaft) 41 can be reduced. As a result, the axial force of the first gear carrier (shaft) 41 and the axial force of the second gear carrier (retainer) 42 can be stabilized, and a preload can be uniformly applied to the main bearing 6.

[0192] Furthermore, by making the hardness of the internal thread portion 200 of the second gear carrier (retainer) 42 lower than that of the bolt 101, the thread teeth 210 of the internal thread portion 200 can be actively elastically deformed. As a result, the contact area between the thread teeth 110 of the bolt 101 and the thread teeth 210 provided to the second gear carrier 42 can be increased, thereby stabilizing the axial force.

[0193] Furthermore, in the first embodiment described above, the eccentric oscillating gear device 1 may also be a so-called hollow shaft reducer (gearbox) in which the rotating shaft serving as the input is hollow.

[0194] In the first embodiment described above, a structure was described in which two fastening parts 100 are formed in each of the three support sections 44, but the structure is not limited to this. As long as the fastening parts 100 are located on the same circle centered on the axis C1 at each support section 44 and are in a symmetrical position at each support section 44, the number of fastening parts 100 can be appropriately changed.

[0195] For example, it can also be configured with three fastening parts 100 respectively on the three support sections 44. In this case, besides Figure 2 In addition to the two locations shown, a third fastening part 100 can be provided at an equal distance from the two fastening parts 100 and on a circle smaller than the two fastening parts 100 with the axis C1 as the center.

[0196] Alternatively, it can be configured such that each of the three support sections 44 has a fastening section 100.

[0197] Furthermore, the fastening part 100 can employ a structure with the aforementioned characteristics for the internal thread part 200. The bolt 101 can also employ a structure with conventional characteristics. Alternatively, the fastening part 100 can employ a structure with the aforementioned characteristics for the external thread part 103, and a structure with conventional characteristics for the internal thread part 200. Moreover, the various structures of the fastening part 100 can be combined and used separately.

[0198] <Second Implementation>

[0199] Hereinafter, a second embodiment of the eccentric oscillating gear device of the present invention will be described based on the accompanying drawings.

[0200] Figure 5 This is a cross-sectional view showing the eccentric oscillating gear device of this embodiment.

[0201] This embodiment differs from the first embodiment described above in points related to the crankshaft. Figure 5 In the figure, reference numeral 3000 indicates an eccentric oscillating gear device.

[0202] In this embodiment, the eccentric oscillating gear device (reducer) 3000 is configured as a so-called central crankshaft type. For example... Figure 5 As shown, the eccentric oscillating gear device 3000 of this embodiment includes an outer cylinder 3300 and an outer wall 3740.

[0203] The eccentric oscillating gear unit 3000 includes a gear carrier 3400C, a crankshaft assembly 3500C, a gear section 3600C, two main bearings 3710C and 3720C, and an input gear 3730C.

[0204] Figure 5 The output axis 3C1 shown corresponds to the central axis (axis) of the two main bearings 3710C and 3720C, as well as the input gear 3730C. The outer cylinder 3300 and the gear carrier 3400C can rotate relative to each other about the output axis 3C1.

[0205] The driving force generated by the motor (not shown) and other drive sources (not shown) is input to the crankshaft assembly 3500C via the input gear 3730C extending along the output axis 3C1. The driving force input to the crankshaft assembly 3500C is transmitted to the gear section 3600C, which is disposed in the internal space enclosed by the outer cylinder 3300 and the gear carrier 3400C.

[0206] Two main bearings 3710C and 3720C are embedded in the annular space formed between the outer cylinder 3300 and the gear carrier 3400C surrounded by the outer cylinder 3300. The outer cylinder 3300 or the gear carrier 3400C rotates about the output axis 3C1 under the action of the driving force transmitted to the gear section 3600C.

[0207] The gear carrier 3400C includes a base (first gear carrier) 3410C and an end plate (second gear carrier) 3420C.

[0208] The gear carrier 3400C is generally cylindrical. The end plate 3420C is roughly circular. The outer circumferential surface of the end plate 3420C is partially surrounded by the second cylindrical portion 3312. The main bearing 3720C is embedded in the annular gap between the second cylindrical portion 3312 and the circumferential surface of the end plate 3420C. The outer circumferential surface of the end plate 3420C is formed by the rollers of the main bearing 3720C rolling directly on the end plate 3420C.

[0209] The base portion 3410C includes a base plate portion 3411C and a plurality of shaft portions 3412C. The outer peripheral surface of the base plate portion 3411C is partially surrounded by a third cylindrical portion 3313. A main bearing 3710C is embedded in an annular gap between the third cylindrical portion 3313 and the outer peripheral surface of the base plate portion 3411C. The outer peripheral surface of the base plate portion 3411C is formed by the rollers of the main bearing 3710C rolling directly on the outer peripheral surface of the base plate portion 3411C.

[0210] The substrate portion 3411C separates from the end plate 3420C in the extending direction of the output axis 3C1. The substrate portion 3411C and the end plate 3420C are substantially coaxial. That is, the output axis 3C1 corresponds to the central axis of the substrate portion 3411C and the end plate 3420C.

[0211] The substrate portion 3411C includes an inner surface 3415C and an outer surface 3416C on the opposite side of the inner surface 3415C. The inner surface 3415C is opposite to the gear portion 3600C. The inner surface 3415C and the outer surface 3416C are along an imaginary plane (not shown) orthogonal to the output axis 3C1.

[0212] A central through-hole 3417C is formed in the substrate portion 3411C. The central through-hole 3417C extends along the output axis 3C1 between the inner surface 3415C and the outer surface 3416C. The output axis 3C1 corresponds to the central axis of the central through-hole 3417C.

[0213] End plate 3420C includes an inner surface 3421C and an outer surface 3422C on the opposite side of the inner surface 3421C. The inner surface 3421C is opposite to the gear portion 3600C. The inner surface 3421C and the outer surface 3422C are along an imaginary plane (not shown) orthogonal to the output axis 3C1.

[0214] A central through hole 3423C is formed in end plate 3420C. The central through hole 3423C extends along the output axis 3C1 between the inner surface 3421C and the outer surface 3422C. The output axis 3C1 corresponds to the central axis of the central through hole 3423C.

[0215] Multiple shaft portions 3412C extend from the inner surface 3415C of the base plate portion 3411C toward the inner surface 3421C of the end plate 3420C. The end plate 3420C is connected to the front end face of each of the multiple shaft portions 3412C. The end plate 3420C can also be connected to the front end face of each of the multiple shaft portions 3412C using a fastening part 100 consisting of a bolt 101 and an internal thread portion 200, as well as a locating pin, etc.

[0216] [Fastening Part]

[0217] Fastening part 100 is configured to be with Figure 3 , Figure 4 The structure shown in the first embodiment is equivalent to the structure shown; therefore, the labeling is the same as... Figure 3 , Figure 4 The same reference numerals are used in the accompanying drawings of the first embodiment shown, and their descriptions are omitted.

[0218] The gear portion 3600C is disposed between the inner surface 3415C of the base plate portion 3411C and the inner surface 3421C of the end plate 3420C. A plurality of shaft portions 3412C pass through the gear portion 3600C and are connected to the end plate 3420C.

[0219] The gear section 3600C includes two oscillating gears 3610C and oscillating gear 3620C.

[0220] The oscillating gear 3610C is disposed between the end plate 3420C and the oscillating gear 3620C. The oscillating gear 3620C is disposed between the base plate portion 3411C and the oscillating gear 3610C. The oscillating gear 3610C and the oscillating gear 3620C can also be formed based on a common design drawing. The oscillating gear 3610C and the oscillating gear 3620C can be either a subcycloidal gear or a cycloidal gear.

[0221] The principle of this embodiment is not limited to the specific type of gear used as the oscillating gear 3610C and the oscillating gear 3620C.

[0222] Oscillating gears 3610C and 3620C mesh with multiple internal toothed pins 3320, respectively. If the crankshaft assembly 3500C rotates about the output axis 3C1, the oscillating gears 3610C and 3620C, while meshing with the internal toothed pins 3320, move around within the housing 3310 (i.e., oscillating rotation). During this period, the centers of the oscillating gears 3610C and 3620C rotate around the output axis 3C1. The relative rotation of the outer cylinder 3300 and the gear carrier 3400C is caused by the oscillating rotation of the oscillating gears 3610C and 3620C.

[0223] A through hole is formed at the center of each of the oscillating gears 3610C and 3620C. The crankshaft assembly 3500C is embedded in the through holes formed at the centers of the oscillating gears 3610C and 3620C.

[0224] Multiple through holes are formed in the oscillating gears 3610C and 3620C respectively, corresponding to multiple shaft portions 3412C arranged along a predetermined imaginary circle around the output axis 3C1. The multiple shaft portions 3412C pass through these through holes. The size of these through holes is set in a manner that prevents interference between the multiple shaft portions 3412C and the oscillating gears 3610C and 3620C.

[0225] The crankshaft assembly 3500C includes a crankshaft 3520C, two journal bearings 3531C and 3532C, and two crankshaft bearings 3541C and 3542C.

[0226] The crankshaft 3520C includes a first journal 3521C, a second journal 3522C, a first eccentric portion 3523C, and a second eccentric portion 3524C.

[0227] The first journal 3521C extends along the output axis 3C1 and is inserted into the central through hole 3423C of the end plate 3420C. The second journal 3522C is located on the opposite side of the first journal 3521C and extends along the output axis 3C1, and is inserted into the central through hole 3417C of the base plate portion 3411C.

[0228] Journal bearing 3531C is embedded in the annular space between the first journal 3521C and the inner wall of the end plate 3420C forming the central through hole 3423C. As a result, the first journal 3521C is connected to the end plate 3420C. Journal bearing 3532C is embedded in the annular space between the second journal 3522C and the inner wall of the base plate portion 3411C forming the central through hole 3417C. As a result, the second journal 3522C is connected to the base plate portion 3411C.

[0229] Therefore, the gear carrier 3400C can support the crankshaft assembly 3500C. In this embodiment, the first end wall is exemplified by the end plate 3420C. The second end plate is exemplified by the base plate portion 3411C.

[0230] The first eccentric portion 3523C is located between the first journal 3521C and the second eccentric portion 3524C. The second eccentric portion 3524C is located between the second journal 3522C and the first eccentric portion 3523C. The crankshaft bearing 3541C is embedded in a through hole formed in the center of the oscillating gear 3610C and is connected to the first eccentric portion 3523C. As a result, the oscillating gear 3610C is mounted on the first eccentric portion 3523C. The crankshaft bearing 3542C is embedded in a through hole formed in the center of the oscillating gear 3620C and is connected to the second eccentric portion 3524C. As a result, the oscillating gear 3620C is mounted on the second eccentric portion 3524C.

[0231] The first journal 3521C and the second journal 3522C are approximately coaxial and rotate about the output axis 3C1. The first eccentric portion 3523C and the second eccentric portion 3524C are each formed in a cylindrical shape and are eccentric relative to the output axis 3C1. The first eccentric portion 3523C and the second eccentric portion 3524C rotate eccentrically relative to the output axis 3C1, causing the oscillating gear 3610C and the oscillating gear 3620C to oscillate and rotate. In this embodiment, the eccentric portion is exemplified by one of the first eccentric portion 3523C and the second eccentric portion 3524C.

[0232] With the outer cylinder 3300 fixed, the oscillating gears 3610C and 3620C mesh with multiple internal toothed pins 3320 of the outer cylinder 3300. Therefore, the oscillating rotation of the oscillating gears 3610C and 3620C is converted into the rotational motion of the crankshaft 3520C about the output axis 3C1 and the rotation of the base plate portion 3411C. The end plate 3420C is connected to the first journal 3521C, and the base plate portion 3411C is connected to the second journal 3522C. Thus, the rotational motion of the crankshaft 3520C is converted into the rotational motion of the end plate 3420C and the base plate portion 3411C about the output axis 3C1. The rotational phase difference between the oscillating gears 3610C and 3620C is determined by the difference in the eccentric direction between the first eccentric portion 3523C and the second eccentric portion 3524C.

[0233] In contrast, with the gear carrier 3400C fixed, the oscillating gears 3610C and 3620C mesh with multiple internal toothed pins 3320 of the outer cylinder 3300. Therefore, the oscillating rotation of the oscillating gears 3610C and 3620C is converted into the rotational motion of the outer cylinder 3300 about the output axis 3C1. The input gear 3730C extends along the output axis 3C1 and penetrates the support wall 3742. The input gear 3730C penetrates the space 3750 enclosed by the outer wall 3740. A through hole 3525 extending along the output axis 3C1 is formed in the crankshaft 3520C. The front end of the input gear 3730C is inserted into the through hole 3525.

[0234] A keyway 3732 is formed at the front end of the input gear 3730C. Another keyway 3526 is formed on the inner wall surface of the crankshaft 3520C, forming a through-hole 3525. Keyways 3732 and 3526 extend substantially parallel to the output axis 3C1. A key 3733 is inserted into keyways 3732 and 3526. As a result, the input gear 3730C is connected to the crankshaft 3520C. If the input gear 3730C rotates about the output axis 3C1, the crankshaft 3520C rotates about the output axis 3C1. This results in the oscillating rotation of the oscillating gears 3610C and oscillating gear 3620C.

[0235] The central through hole 3417C formed in the substrate portion 3411C includes a first cavity portion 3491 and a second cavity portion 3492. Both the first cavity portion 3491 and the second cavity portion 3492 have a circular cross-section. The cross-sectional area of ​​the first cavity portion 3491 is smaller than that of the second cavity portion 3492.

[0236] The first cavity portion 3491 is provided with a second journal 3522C and a journal bearing 3532C. The outer surface 3416C of the base plate portion 3411C is connected by pressing against the target member (not shown).

[0237] A flange 3314 is formed along the entire circumference of the outer periphery of the housing 3310, and this flange 3314 is connected to the outer wall 3740. The outer wall 3740 has an outer cylindrical wall 3741. The front end portion 3741a of the outer cylindrical wall 3741 is formed flat. An internal thread portion 250 is formed at the front end portion 3741a of the outer cylindrical wall 3741 as a mounting fastener 150.

[0238] A flange portion 3314 is provided on the outer periphery of the housing 3310, and has a through hole 3315 extending through the flange portion 3314 in the direction along the axis 3C1. The through holes 3315 are arranged at arbitrary intervals in the circumferential direction. The through holes 3315 are fastening holes through which bolts 151, which are used to fasten the eccentric oscillating gear device 3000 and the outer wall 3740, which is part of the robot R, pass. The bolts 151, as fastening members, pass through the through holes 3315. The internal thread portion 250 of the outer wall 3740 and the bolts 151 constitute the mounting fastening portion 150.

[0239] [Installation and fastening]

[0240] The mounting fastener 150 has a basis. Figure 3 , Figure 4 The structure of the fastening part 100 in the first embodiment is shown. The bolt 151 and the internal thread 250 that mount the fastening part 150 are... Figure 3 , Figure 4 The bolt 101 and the internal thread 200 of the fastening part 100 shown in the first embodiment correspond to each other. Figure 5 In the figure, these will be represented by reference numerals 150, 151, and 250. Otherwise, the reference numerals will be... Figure 3 , Figure 4 The fastening part 100 in the first embodiment shown uses the same reference numerals, and its description is omitted.

[0241] When installing the fastener 150, also with Figure 3 , Figure 4 Similarly, in the fastening part 100 shown in the first embodiment, due to the hardness difference between the external thread part 103 and the internal thread part 250, the thread teeth 110 and 210 deform. As a result, when fastening the eccentric oscillating gear device 3000 to the outer wall 3740, which is a part of the robot R, the contact area between the external thread part 103 and the internal thread part 250 at the mounting fastening part 150 can be increased, thereby reducing the deviation of frictional force.

[0242] According to this embodiment, similarly to the embodiment described above, the shaft portion 3412C is fastened to the end plate 3420C. Consequently, the threads 110 and 210 of the external thread portion 103 of the bolt (fastener) 101 and the internal thread portion 200 of the shaft portion 3412C respectively come into contact with each other. At this time, due to the hardness difference between the external thread portion 103 and the internal thread portion 200, the surface shape of the external thread portion 103 is transferred to the internal thread portion 200. Therefore, at the plurality of fastening portions 100, the deviation of frictional force at the contact surfaces of the threads 110 and 210 can be reduced. Therefore, the axial force of the shaft portion 3412C and the end plate 3420C can be stabilized. Therefore, a uniform preload can be applied to the main bearings 3710C and 3720C.

[0243] Furthermore, preload can be uniformly applied to the first journal 3521C and the second journal 3522C used in the crankshaft assembly 3500C. This improves the rotational stability of the eccentric oscillating gear device 3000 and increases the torque density of the eccentric oscillating gear device 3000.

[0244] Simultaneously, due to the hardness difference between thread 110 and thread 210, the surface shape of the external thread portion 103 is transferred to the thread 210 of the internal thread portion 200 provided on the shaft portion 3412C, and this transfer is facilitated. Therefore, the contact area between the thread 110 of the external thread portion 103 and the thread 210 on the internal thread portion 200 side can be increased in the fastening portion 100, thereby stabilizing the axial force.

[0245] In the fastening part 100, the deviation of the frictional force between the contact surface between the bolt 101 and the shaft 3412C can be reduced, thereby stabilizing the axial force of the shaft 3412C and the end plate 3420C. As a result, preload can be applied uniformly to the main bearings 3710C and 3720C.

[0246] Furthermore, by making the hardness of the internal thread portion 200 of the shaft portion 3412C lower than that of the bolt 101, the thread teeth 210 provided in the internal thread portion 200 can be actively elastically deformed by utilizing the thread teeth 110 on the external thread portion 103 side. As a result, the contact area between the thread teeth 110 of the bolt 101 and the thread teeth 210 of the shaft portion 3412C can be increased, thereby stabilizing the axial force.

[0247] According to this embodiment, the axial force of the shaft portion 3412C is stabilized by using the fastening part 100 and the mounting fastening part 150. Therefore, due to the mounting fastening part 150, the eccentric oscillating gear device 3000 is rigidly stable when subjected to torque, and the positional accuracy and trajectory accuracy of the robot R are stabilized at a high level.

[0248] In this embodiment, the same effect as that of the embodiment described above can be achieved.

[0249] <Third Implementation>

[0250] The third embodiment of the industrial robot of the present invention will be described below based on the accompanying drawings.

[0251] Figure 6 This is a schematic diagram representing the robot in this embodiment.

[0252] This embodiment differs from the first and second embodiments described above in points relating to the robot for mounting the eccentric oscillating gear device. Other corresponding components are labeled with the same reference numerals and their descriptions are omitted.

[0253] [Robot (Object Component)]

[0254] In this embodiment, the robot R is preferably an industrial robot, and more preferably a collaborative (cooperative) robot. A collaborative (cooperative) robot refers to a robot that "works in collaboration with operators" in fields such as factory automation (FA).

[0255] In addition, as robot R, a multi-joint robot with multiple reducers (gearboxes) corresponding to either the eccentric oscillating gear unit 1 or the eccentric oscillating gear unit 3000 can be used.

[0256] [Eccentric Oscillating Gear Mechanism]

[0257] An eccentric oscillating gear device 1 or an eccentric oscillating gear device 3000 is provided at the connecting part (joint part of robot R) 330L, connecting part 330U, and connecting part 330S of a pair of rotatably connected arms. The eccentric oscillating gear device 1 or the eccentric oscillating gear device 3000 reduces the motor torque input from a motor (not shown) that serves as a drive source and outputs it at a reduced speed.

[0258] Furthermore, the eccentric oscillating gear device 1 or eccentric oscillating gear device 3000 can be not only the structure described above, but also have a structure capable of changing the rotation of the drive source that generates rotational force. For example, a speed increaser that increases the rotational speed of the drive source that generates rotational force can be used instead of the eccentric oscillating gear device 1 or eccentric oscillating gear device 3000. Therefore, in this embodiment, the eccentric oscillating gear device is also included and referred to as a transmission.

[0259] Robot R has multiple gearboxes (first gearbox 308, second gearbox 314, and third gearbox 320) respectively provided in connecting parts 330S, 330L, and 330U. Each of these gearboxes 308, 314, and 320 has a fastening part 100. Furthermore, gearboxes 308, 314, and 320 are all mounted by mounting fastening parts 150.

[0260] Among them, the transmissions 308, 314, and 320, which correspond to the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000, become parts of the robot R.

[0261] The robot R includes: a fixed base 302 that contacts a mounting surface; a rotating head 304 that extends upward from the fixed base 302; multiple arms (first arm 310 and second arm 316) that are rotatably assembled to the rotating head 304; an end effector E that is disposed at the front end of the arm; and multiple gearboxes (first gearbox 308, second gearbox 314 and third gearbox 320).

[0262] The first arm 310 is connected to the rotating head 304 in a rotatable manner via multiple transmissions 308, 314, and 320. The second arm 316 is connected to the first arm 310 in a rotatable manner via the transmission 320. The transmissions 308, 314, and 320 can use either the eccentric oscillating gear device 1 or the eccentric oscillating gear device 3000 described above, or they can be freely combined. This will be explained in detail below.

[0263] The rotating head 304 is mounted on the fixed base 302 in a manner that allows it to rotate freely about the S-axis. The rotating head 304 rotates about the S-axis using a first servo motor 306 and a first gearbox 308 as drive sources. The first arm 310 is mounted on the upper part of the rotating head 304 in a manner that allows it to swing back and forth about the L-axis. The first arm 310 swings back and forth about the L-axis using a second servo motor 312 and a second gearbox 314 as drive sources. The second arm 316 is mounted on the upper part of the first arm 310 in a manner that allows it to swing up and down about the U-axis. The second arm 316 swings up and down about the U-axis using a third servo motor 318 and a third gearbox 320 as drive sources. This structure allows the end effector E to be driven three-dimensionally.

[0264] According to this embodiment, the axial force of the fastening part 100, shaft part 44, and shaft part 3412C is stabilized. Furthermore, due to the installation of the fastening part 150, the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000 are rigidly stabilized when subjected to torque. Therefore, the positional accuracy and trajectory accuracy of the robot R are further stabilized at a high level.

[0265] In this embodiment, a robot R with the following structure is described: it has a connecting portion 330L and a connecting portion 330U for mounting the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000. This embodiment is not limited to the robot R; for example, the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000 can be mounted on a predetermined industrial machine.

[0266] Even under these conditions, preload can be applied uniformly to main bearings 6, 3710C, and 3720C, thus increasing the probability that industrial machinery will reach its rated life.

[0267] The axial force of the mounting fastener 150 between the industrial machinery and the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000 is stabilized, thus further increasing the probability that the industrial machinery can reach its rated life.

[0268] Examples of industrial machinery in this embodiment include locators and AGVs (Automatic Guided Vehicles).

[0269] In the embodiments described above, examples of applying the fastening part 100 and the mounting fastening part 150 to the eccentric oscillating gear device 1 and the eccentric oscillating gear device 3000 have been given, but they can also be applied to eccentric oscillating gear devices with different structures. For example, the fastening part 100 and the mounting fastening part 150 can be applied to an eccentric oscillating gear device that uses planetary gears.

[0270] In the embodiments disclosed in this specification, a component composed of multiple objects can be made into one integrated object; conversely, a component composed of a single object can be divided into multiple objects. Regardless of whether it is integrated or not, it can be constructed in a manner that achieves the purpose of the invention.

[0271] In the fastening part of this invention, a bolt with an external thread having a hardness higher than that of the internal thread is used for fastening, thereby causing plastic deformation of the surface of the thread teeth of the internal thread by the external thread. This increases the contact area between the internal and external threads. Consequently, the frictional force constituting the fastening force can be uniformized among multiple fastening parts. Therefore, the axial force of the fastening part is increased during the fastening of the eccentric oscillating gear device.

[0272] In cases where the hardness difference between the internal and external threads is small, the surface friction generated in the internal thread is affected by the machining accuracy of the internal thread, making it difficult to uniformize the axial force. In contrast, in the eccentric oscillating gear device of the present invention, the hardness difference between the internal and external threads is large, thereby increasing the contact area between them. Therefore, it is possible to improve the axial force.

[0273] The inventors of this application have studied the mechanism for increasing axial force at the fastening part as follows.

[0274] The increased contact area between the internal and external threads arises because, during bolt tightening, the softer internal thread undergoes plastic deformation, mimicking the harder external thread. This plastic deformation of the internal thread, mimicking the external thread, occurs on the surfaces of the contacting threads. In other words, it is believed that when the bolt is tightened to the internal thread, the surface of the softer internal thread undergoes plastic deformation, mimicking the surface of the harder external thread.

[0275] That is, due to the tightening force applied by the bolt, the minute shape of the thread teeth on the surface of the internal thread becomes similar to the minute shape of the thread teeth on the surface of the external thread. In other words, there is a hardness difference between the internal and external threads, so that the surface roughness of the internal thread becomes similar to the surface roughness of the external thread for the thread teeth that are in contact with each other during tightening.

[0276] Consider the scenario where the surface roughness of the internal thread is smaller than that of the external thread before tightening. Therefore, due to the hardness difference between the internal and external threads, the surface roughness of the internal thread after tightening is closer to that of the harder external thread than the internal thread before tightening. In other words, the surface roughness of the internal thread, which was smaller than that of the external thread before tightening, becomes close to that of the external thread after tightening. In this case, the surface roughness of the internal thread increases both before and after tightening.

[0277] For example, if the internal thread before tightening is HCR38 with a surface roughness of Ra0.3 to 0.5 (μm) and the external thread before tightening is HCR44 with a surface roughness of Ra0.5 to 1.0 (μm), the internal thread after tightening will have a surface roughness of Ra0.3 to 1.0 (μm).

[0278] Considering that the surface roughness of the internal thread before tightening is the same as that of the external thread, and due to the hardness difference between the internal and external threads, the surface roughness of the internal thread after tightening is closer to that of the harder external thread than the surface roughness of the internal thread before tightening. In other words, the surface roughness of the internal thread, which was the same as that of the external thread before tightening, becomes close to that of the external thread after tightening. In this case, the surface roughness of the internal thread is approximately the same before and after tightening.

[0279] For example, if the internal thread before tightening is HCR38 with a surface roughness of Ra0.3 to 0.5 (μm) and the external thread before tightening is HCR44 with a surface roughness of Ra0.3 to 0.5 (μm), the internal thread after tightening will have a surface roughness of Ra0.3 to 0.5 (μm).

[0280] Consider the scenario where the surface roughness of the internal thread is greater than that of the external thread before tightening. Therefore, due to the hardness difference between the internal and external threads, the surface roughness of the internal thread after tightening is closer to that of the harder external thread than the internal thread before tightening. In other words, the surface roughness of the internal thread, which was greater than that of the external thread before tightening, becomes close to that of the external thread after tightening. In this case, the surface roughness of the internal thread decreases before and after tightening.

[0281] For example, if the internal thread before tightening is HCR38 with a surface roughness of Ra0.5 to 1.0 (μm) and the external thread before tightening is HCR44 with a surface roughness of Ra0.2 to 0.5 (μm), the internal thread after tightening will have a surface roughness of Ra0.2 to 0.8 (μm).

[0282] Thus, regardless of how the surface roughness of the internal thread changes, the surface of the internal thread matches the surface of the external thread, thereby increasing the contact area at the fastening point and improving the axial force. Furthermore, as mentioned above, the surface roughness of the internal thread after fastening depends on the surface roughness of the external thread.

[0283] Generally, in threaded fastening, a smaller surface roughness at the contact surface of the fastening part is preferred in order to increase axial force. In contrast, as described above, in the present invention, axial force can be increased regardless of the surface roughness at the contact surface of the fastening part, especially the surface roughness of the internal thread.

[0284] The axial force is calculated as follows.

[0285] Axial force = Fastening torque / (Thread surface friction + Base surface friction + Elastic deformation)

[0286] Therefore, in addition to the tightening torque affecting the axial force, the coefficient of friction also affects the axial force. There is a relationship where a higher coefficient of friction results in a lower axial force. Consequently, if the coefficient of friction varies across multiple fasteners, the axial force will become unstable.

[0287] In this invention, by using a bolt and an internal thread portion with a hardness difference, the internal thread portion can be matched with the external thread portion even if the internal thread portion has any surface roughness value. That is, the surface roughness of the internal thread portion can be made close to the surface roughness of the external thread portion. Therefore, even when tightening is performed with the same tightening torque value, the axial force at the fastening part of this invention can be stabilized compared to the conventional case where a bolt and internal thread portion without a hardness difference are used.

[0288] In this invention, friction can be increased on the fastening surface of the fastening part, and the contact area can be increased on the fastening surface of the fastening part. Therefore, the fastening torque can be improved.

[0289] Furthermore, it is conceivable to obtain the same level of axial force among multiple fasteners.

[0290] In cases where both high-hardness and low-hardness bolts are tightened to the same internal thread with the same torque, the low-hardness bolt may break. In contrast, the high-hardness bolt will not break.

[0291] In other words, in this invention, to stabilize the coefficient of friction, a bolt with higher hardness is used to make the surface roughness of the internal thread resemble the surface roughness of the bolt. Furthermore, by stabilizing the coefficient of friction, bolt breakage can be prevented even when tightened with the same tightening torque.

[0292] <Verification Example 1>

[0293] As a verification example of the mechanism, using Figures 1-4 The eccentric oscillating gear device (transmission) 1 of the embodiment shown underwent a fastening test at the fastening part 100.

[0294] In this test, a specimen and bolt 101 corresponding to the fastening part 100 of the eccentric oscillating gear device (gearbox) 1 were used.

[0295] Specifically, a specimen was prepared having an internal thread portion 200 corresponding to the fastening portion 100, and being divided in half along the axis C5 of the internal thread portion 200. Next, the specimen was assembled in such a way that the internal thread portion 200 was restored to its original shape. At this time, a specimen with at least an internal thread portion 200 having a Rockwell hardness (HRC) of 38 was prepared.

[0296] In addition, bolts 101 with a Rockwell hardness (HRC) of at least 44 are prepared for the external thread portion 103.

[0297] The bolt 101 is tightened to the internal thread portion 200 of the specimen with a predetermined tightening torque. Then, the specimen is disassembled to expose the inner circumferential surface of the internal thread portion 200, and the bolt 101 is separated from the internal thread portion 200.

[0298] In this state, the surface roughness was measured on both the meshing surfaces of the internal thread portion 200 and the external thread portion 103. For the surface roughness measurement, on the bolt 101 meshing with the internal thread portion 200, the surfaces of the thread teeth that contact the internal thread portion 200, specifically the third and fourth threads from the position near the head 104, were measured. Similarly, the surface roughness of the internal thread portion 200 was measured at positions corresponding to the previously measured positions on the bolt 101.

[0299] The following describes the specimen, bolt 101, and various elements in the fastening test.

[0300] Bolt 101 size: M12

[0301] • Reference dimension (nominal diameter) of the outer diameter of the external thread section 103: 12 [mm]

[0302] • Reference dimension of the effective diameter of the external thread section 103: 10.863 [mm]

[0303] • Reference dimension of the root diameter of the external thread section 103: 10.106 [mm]

[0304] • Pitch: 1.75 mm

[0305] • Reference dimension (nominal diameter) of the root diameter of the 200 internal thread section: 12 [mm]

[0306] • Reference dimension for the effective diameter of the 200mm internal thread section: 10.863mm

[0307] • Reference dimension of the inner diameter of the 200mm internal thread section: 10.106 mm

[0308] • Original triangle height of internal thread section 200: 1.516 [mm]

[0309] • Pitch: 1.75 mm

[0310] Test conditions

[0311] • Tightening torque: 156 N·m

[0312] • Measured surface roughness: Ra (μm), Rpk (μm), Rv (μm)

[0313] From these measurement data, the preferred relationship between the surface roughness of the external thread and the surface roughness of the internal thread is derived as follows. (See Tables 1-7 and...) Figures 7-12 The figure represents the relationship between the surface roughness of the external thread and the surface roughness of the internal thread.

[0314] Table 1

[0315]

[0316] Table 2

[0317]

[0318] Table 3

[0319]

[0320] Table 4

[0321]

[0322] Table 5

[0323]

[0324] Table 6

[0325]

[0326] Table 7

[0327]

[0328] Figure 7 This is a graph showing the relationship between the surface roughness FRa (μm) of the internal thread portion and the surface roughness MRa (μm) of the external thread portion / the surface roughness FRa (μm) of the internal thread portion: RRa in the eccentric oscillating gear device of the present invention. Figure 8 This is a graph showing the relationship between the surface roughness FRa (μm) of the internal thread portion and the surface roughness MRa (μm) of the external thread portion / the surface roughness FRa (μm) of the internal thread portion: RRa in the eccentric oscillating gear device of the present invention. Figure 9 This is a graph showing the relationship between the surface roughness FRpk (μm) of the internal thread portion and the surface roughness MRpk (μm) of the external thread portion / the surface roughness FRpk (μm) of the internal thread portion in the eccentric oscillating gear device of the present invention: RRpk. Figure 10 This is a graph showing the relationship between the surface roughness FRpk (μm) of the internal thread portion and the surface roughness MRpk (μm) of the external thread portion / the surface roughness FRpk (μm) of the internal thread portion in the eccentric oscillating gear device of the present invention: RRpk. Figure 11This is a graph showing the relationship between the surface roughness FRv (μm) of the internal thread portion and the surface roughness MRv (μm) of the external thread portion / the surface roughness FRv (μm) of the internal thread portion in the eccentric oscillating gear device of the present invention: RRv. Figure 12 This is a graph showing the relationship between the surface roughness FRv (μm) of the internal thread portion and the surface roughness MRv (μm) of the external thread portion / the surface roughness FRv (μm) of the internal thread portion in the eccentric oscillating gear device of the present invention: RRv.

[0329] exist Figure 7 The range represents the preferred relationship between the surface roughness FRa (μm) of the tightened internal thread portion derived from the data and the surface roughness MRa (μm) of the external thread portion / the surface roughness FRa (μm) of the internal thread portion: RRa.

[0330] (4) The preferred relationship between the surface roughness MRa (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRa (μm) of the internally threaded portion after tightening is as follows:

[0331] The surface roughness FRa (μm) of the internal thread portion is in the range of 0.2 to 1.0.

[0332] The ratio RRa = MRa / FRRa is a value in the range of 0.25 to 3.333.

[0333] (5) The preferred relationship between the surface roughness MRa (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRa (μm) of the internally threaded portion after tightening is as follows:

[0334] The surface roughness FRa (μm) and ratio RRa = MRa / FRa of the internal threaded portion are as follows: Figure 7The values ​​are represented by points (FRa, RRa), set as follows: RRa1 (0.3, 3.333), RRa2 (0.4, 2.500), RRa3 (0.5, 2.000), RRa4 (0.6, 1.667), RRa5 (0.7, 1.429), RRa6 (0.8, 1.250), RRa7 (0.9, 1.111), RRa8 (1.0, 1.000), and RRa9 (1.0, 0.500). The values ​​within the range enclosed by points RRa10(0.9, 0.556), RRa12(0.8, 0.250), RRa13(0.7, 0.286), RRa14(0.6, 0.333), RRa15(0.5, 0.400), RRa16(0.4, 0.500), RRa17(0.3, 0.667), RRa18(0.2, 1.000), and RRa19(0.2, 2.500).

[0335] Furthermore, when the surface roughness MbRa (μm) of the external thread portion before tightening is greater than the surface roughness FbRa (μm) of the internal thread portion before tightening, the relationship between FbRa (internal thread) and MbRa (external thread) is as follows:

[0336] The preferred relationship between the surface roughness MRa (μm) of the externally threaded portion after tightening and the surface roughness FRa (μm) of the internally threaded portion after tightening is as follows:

[0337] The surface roughness FRa (μm) and ratio RRa = MRa / FRa of the internal threaded portion are as follows: Figure 8 The values ​​are represented by points (FRa, RRa) and set to the range enclosed by points RRa19 (0.2, 2.500), RRa20 (0.3, 1.667), RRa21 (0.4, 1.250), RRa22 (0.5, 1.000), RRa23 (0.6, 0.833), RRa24 (0.7, 0.714), RRa11 (0.8, 0.625), RRa12 (0.8, 0.250), RRa13 (0.7, 0.286), RRa14 (0.6, 0.333), RRa15 (0.5, 0.400), RRa16 (0.4, 0.500), RRa17 (0.3, 0.667), and RRa18 (0.2, 1.000).

[0338] Furthermore, when the surface roughness MbRa (μm) of the external thread portion before tightening is less than the surface roughness FbRa (μm) of the internal thread portion before tightening,

[0339] The preferred relationship between the surface roughness MRa (μm) of the externally threaded portion after tightening and the surface roughness FRa (μm) of the internally threaded portion after tightening is as follows:

[0340] The surface roughness FRa (μm) and ratio RRa = MRa / FRa of the internal threaded portion are as follows: Figure 8 The values ​​are represented by points (FRa, RRa), set as follows: RRa1 (0.3, 3.333), RRa2 (0.4, 2.500), RRa3 (0.5, 2.000), RRa4 (0.6, 1.667), RRa5 (0.7, 1.429), RRa6 (0.8, 1.250), RRa7 (0.9, 1.111), and RRa8 (1.0, 1.00). The values ​​within the range enclosed by points RRa9(1.0, 0.500), RRa10(0.9, 0.556), RRa11(0.8, 0.625), RRa24(0.7, 0.714), RRa23(0.6, 0.833), RRa22(0.5, 1.000), RRa21(0.4, 1.250), and RRa20(0.3, 1.667).

[0341] Furthermore, when the surface roughness MbRa (μm) of the external thread portion before tightening is approximately equal to the surface roughness FbRa (μm) of the internal thread portion before tightening, the relationship is FbRa (internal thread) ≈ MbRa (external thread).

[0342] The preferred relationship between the surface roughness MRa (μm) of the externally threaded portion after tightening and the surface roughness FRa (μm) of the internally threaded portion after tightening is as follows:

[0343] The surface roughness FRa (μm) and ratio RRa = MRa / FRa of the internal threaded portion are as follows: Figure 8 The values ​​are set to the range enclosed by points RRa20 (0.3, 1.667), RRa21 (0.4, 1.250), RRa22 (0.5, 1.000), RRa25 (0.5, 0.600), RRa26 (0.4, 0.750), and RRa27 (0.3, 1.000), represented by points (FRa, RRa).

[0344] exist Figure 9 The range represents the preferred relationship between the surface roughness FRpk (μm) of the tightened internal thread portion derived from the data and the surface roughness MRpk (μm) of the external thread portion / the surface roughness FRpk (μm) of the internal thread portion: RRpk.

[0345] (6) The preferred relationship between the surface roughness MRpk (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRpk (μm) of the internally threaded portion after tightening is as follows:

[0346] The surface roughness FRpk (μm) of the internal thread portion is in the range of 0.2 to 0.6.

[0347] The ratio RRpk = MRpk / FRpk is a value in the range of 0.4 to 5.5.

[0348] (7) The preferred relationship between the surface roughness MRpk (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRpk (μm) of the internally threaded portion after tightening is as follows:

[0349] The surface roughness FRpk (μm) of the internal thread and the ratio RRpk = MRpk / FRpk are as follows: Figure 9 The values ​​are represented by points (FRpk, RRpk) and set to the range enclosed by points RRpk1 (0.2, 5.500), RRpk2 (0.3, 3.667), RRpk3 (0.4, 2.750), RRpk4 (0.5, 2.200), RRpk5 (0.6, 1.833), RRpk6 (0.6, 1.000), RRpk7 (0.5, 0.400), RRpk8 (0.4, 0.500), RRpk9 (0.3, 0.667), and RRpk10 (0.2, 1.000).

[0350] Furthermore, when the surface roughness MbRpk (μm) of the external thread portion before tightening is greater than the surface roughness FbRpk (μm) of the internal thread portion before tightening, the relationship between FbRpk (internal thread) and MbRpk (external thread) is as follows:

[0351] The preferred relationship between the surface roughness MRpk (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRpk (μm) of the internally threaded portion after tightening is as follows:

[0352] The surface roughness FRpk (μm) of the internal thread and the ratio RRpk = MRpk / FRpk are as follows: Figure 10The values ​​are represented by points (FRpk, RRpk) and set to the range enclosed by points RRpk20 (0.2, 2.500), RRpk11 (0.3, 1.667), RRpk16 (0.4, 1.250), RRpk15 (0.5, 1.000), RRpk7 (0.5, 0.400), RRpk8 (0.4, 0.500), RRpk9 (0.3, 0.667), and RRpk10 (0.2, 1.000).

[0353] Furthermore, when the surface roughness MbRpk (μm) of the external thread portion before tightening is less than the surface roughness FbRpk (μm) of the internal thread portion before tightening,

[0354] The preferred relationship between the surface roughness MRpk (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRpk (μm) of the internally threaded portion after tightening is as follows:

[0355] The surface roughness FRpk (μm) and ratio RRpk = MRpk / FRpk of the internal threaded portion are preferably as follows: Figure 10 The values ​​are set as follows, represented by points (FRpk, RRpk): RRpk1(0.2, 5.500), RRpk2(0.3, 3.667), RRpk3(0.4, 2.750), RRpk4(0.5, 2.200), RRpk5(0.6, 1.833), RRpk6(0.6, 1.000), RRpk14(0.5, 1.200), RRpk13(0.4, 1.500), RRpk12(0.3, 2.000), and RRpk21(0.2, 3.000).

[0356] Furthermore, when the surface roughness MbRpk (μm) of the external thread portion before tightening is approximately equal to the surface roughness FbRpk (μm) of the internal thread portion before tightening, the relationship is FbRpk (internal thread) ≈ MbRpk (external thread).

[0357] The preferred relationship between the surface roughness MRpk (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRpk (μm) of the internally threaded portion after tightening is as follows:

[0358] The surface roughness FRpk (μm) of the internal thread and the ratio RRpk = MRpk / FRpk are as follows: Figure 10The values ​​are represented by points (FRpk, RRpk) and set to the range enclosed by points RRpk21 (0.2, 3.000), RRpk12 (0.3, 2.000), RRpk13 (0.4, 1.500), RRpk17 (0.4, 0.750), RRpk18 (0.3, 1.000), and RRpk19 (0.2, 1.500).

[0359] exist Figure 11 The range represents the preferred relationship between the surface roughness FRv (μm) of the tightened internal thread portion derived from the data and the surface roughness MRv (μm) of the external thread portion / the surface roughness FRv (μm) of the internal thread portion: RRv.

[0360] (8) The preferred relationship between the surface roughness MRv (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRv (μm) of the internally threaded portion after tightening is as follows:

[0361] The surface roughness FRv (μm) of the internal thread portion is a value in the range of 0.4 to 1.1.

[0362] The ratio RRv = MRv / FRv is a value in the range of 0.364 to 1.833.

[0363] (9) The preferred relationship between the surface roughness MRv (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRv (μm) of the internally threaded portion after tightening is as follows:

[0364] The surface roughness FRv (μm) and ratio RRv = MRv / FRv of the internal threaded portion are as follows: Figure 11 The values ​​are represented by points (FRv, RRv), set as follows: RRv1 (0.4, 1.500), RRv2 (0.5, 1.200), RRv3 (0.6, 1.833), RRv4 (0.7, 1.571), RRv5 (0.8, 1.375), RRv6 (0.9, 1.222), RRv7 (1.0, 1.100), and RRv8 (1.1, 1.00). The values ​​within the range enclosed by points RRv9(1.1, 0.364), RRv10(1.0, 0.400), RRv11(0.9, 0.444), RRv12(0.8, 0.500), RRv13(0.7, 0.571), RRv14(0.6, 0.667), RRv15(0.5, 0.800), and RRv16(0.4, 1.000).

[0365] Furthermore, when the surface roughness MbRv (μm) of the external thread portion before tightening is greater than the surface roughness FbRv (μm) of the internal thread portion before tightening, the relationship between FbRv (internal thread) and MbRv (external thread) is as follows:

[0366] The preferred relationship between the surface roughness MRv (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRv (μm) of the internally threaded portion after tightening is as follows:

[0367] The surface roughness FRv (μm) and ratio RRv = MRv / FRv of the internal threaded portion are as follows: Figure 12 The values ​​are represented by points (FRv, RRv) and set to the range enclosed by points RRv17 (0.6, 1.000), RRv22 (0.7, 0.857), RRv21 (0.8, 0.750), RRv20 (0.9, 0.667), RRv19 (1.0, 0.600), RRv18 (1.1, 0.545), RRv9 (1.1, 0.364), RRv10 (1.0, 0.400), RRv11 (0.9, 0.444), RRv12 (0.8, 0.500), RRv13 (0.7, 0.571), and RRv14 (0.6, 0.667).

[0368] Furthermore, when the surface roughness MbRv (μm) of the external thread portion before tightening is less than the surface roughness FbRv (μm) of the internal thread portion before tightening,

[0369] The preferred relationship between the surface roughness MRv (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRv (μm) of the internally threaded portion after tightening is as follows:

[0370] The surface roughness FRv (μm) and ratio RRv = MRv / FRv of the internal threaded portion are as follows: Figure 12 The values ​​are represented by points (FRv, RRv) and set to the range enclosed by points RRv3 (0.6, 1.833), RRv4 (0.7, 1.571), RRv5 (0.8, 1.375), RRv6 (0.9, 1.222), RRv7 (1.0, 1.100), RRv8 (1.1, 1.000), RRv18 (1.1, 0.545), RRv19 (1.0, 0.600), RRv20 (0.9, 0.667), RRv21 (0.8, 0.750), RRv22 (0.7, 0.857), and RRv17 (0.6, 1.000).

[0371] Furthermore, when the surface roughness MbRv (μm) of the external thread portion before tightening is approximately equal to the surface roughness FbRv (μm) of the internal thread portion before tightening, the relationship is FbRv (internal thread) ≈ MbRv (external thread).

[0372] The preferred relationship between the surface roughness MRv (μm) of the externally threaded portion after interlocking and tightening and the surface roughness FRv (μm) of the internally threaded portion after tightening is as follows:

[0373] The surface roughness FRv (μm) and ratio RRv = MRv / FRv of the internal threaded portion are as follows: Figure 12 The values ​​are set to the range enclosed by points RRv1 (0.4, 1.500), RRv2 (0.5, 1.200), RRv15 (0.5, 0.800), and RRv16 (0.4, 1.000), represented by points (FRv, RRv).

[0374] The reason for setting the relationship between the surface roughness of the internal threads and the external threads to any of the aforementioned ranges is that, during bolt tightening, the thread teeth of the internal threads, which have lower hardness, are plastically deformed in a manner similar to the thread teeth of the external threads, which have higher hardness. This plastic deformation of the internal threads, mimicking the external threads, occurs on the surfaces of the internal and external threads that are in contact. In other words, by setting the surface roughness relationship to any of the aforementioned ranges, it is possible to plastically deform the minute shapes on the surface of the internal threads, when tightening force is applied due to bolt tightening, to approximate the minute shapes on the surface of the external threads. This is because, by having a hardness difference between the external and internal threads, the surface roughness of the internal threads can be made close to that of the external threads at the surfaces in contact during tightening.

[0375] These results show that by using an external thread with a higher hardness than the internal thread, regardless of the surface roughness before tightening, the surface of the internal thread plastically deforms in a manner that mimics the surface of the external thread. In other words, preferably, before tightening, regardless of the surface roughness of the internal and external threads, the surface of the tightened internal thread will approximate the surface roughness of the harder external thread. To achieve this preferred state, the relationship between the surface roughness of the tightened internal thread and the surface roughness of the external thread needs to be within any of the aforementioned ranges.

[0376] When the surface roughness of the internal thread and the external thread are both within the ranges mentioned above after tightening, the surface of the internal thread can match the surface of the external thread regardless of how the surface roughness changes before and after tightening. This increases the contact area at the tightening point, thereby improving the axial force.

[0377] In contrast, if the surface roughness of the internal thread and the external thread after tightening is not within either of the aforementioned ranges, the axial force at the tightening point cannot be increased. Therefore, there is a possibility of axial force deviations, breakage, or other adverse conditions occurring at multiple tightening points, making this method less than ideal.

[0378] By setting the surface roughness of the tightened internal thread and the surface roughness of the external thread to either of the aforementioned ranges, in the case of an eccentric oscillating gear device of the present invention having multiple fastening parts, it is possible to suppress the upper limit of axial force deviation at the bolt yield point. As a result, according to the present invention, the torque density used to achieve the increase in axial force can be improved.

[0379] Next, the increase in contact area and tightening torque at the fastening part caused by the bolt size will be explained.

[0380] The study investigated the changes in contact area and tightening torque, which corresponded to changes in bolt size and the corresponding pitch.

[0381] The contact area A is calculated as follows.

[0382] A = (D 2 -D1 2 ) / 4

[0383] Among them, A, D, and D1 are described as follows:

[0384] A: The contact area of ​​one thread tooth in the internal thread portion [mm] 2 ]

[0385] D: Nominal diameter of the internal thread [mm]

[0386] D1: Reference dimension of the inner diameter of the internal thread (D-1.0825P) [mm].

[0387] in addition,

[0388] P: Pitch of the internal thread [mm].

[0389] The following shows the bolt size, pitch [mm], and contact area [mm]. 2 Changes in tightening torque [Nm].

[0390] M5, 0.8, 6.21, 7.16

[0391] M6, 1.0, 9.28, 12.1

[0392] M8, 1.25, 15.57, 29.4

[0393] M10, 1.5, 23.44, 58.8

[0394] M12, 1.75, 32.89, 1.2

[0395] M14, 2, 43.93, 163

[0396] M16, 2, 50.73, 252

[0397] M18, 2.5, 70.77, 348

[0398] M20, 2.5, 79.27, 493

[0399] At this point, the tightening torque is the value when the bolt is tightened at 50% of its yield point axial force.

[0400] Based on the results, the tightening torque can be varied by adjusting the bolt size. Accordingly, the preferred range of surface roughness for both the internal and external threads can be changed accordingly.

Claims

1. An eccentric oscillating gear device, wherein, This eccentric oscillating gear device has the following features: case; The first component is supported on the housing by means of a first bearing; The second component is supported on the housing by means of a second bearing; as well as A fastening part that fastens the first component and the second component in the axial direction of the housing. The fastening part has: An internal thread portion, formed on the first member; and Fasteners having external threads, The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener. When the internal thread portion is threaded into the external thread portion, the external thread portion causes the small protrusions on the surface of the thread teeth of the internal thread portion to undergo plastic deformation.

2. The eccentric oscillating gear device according to claim 1, wherein, The hardness of the internal thread portion is made smaller than the Brinell hardness HB353.

3. The eccentric oscillating gear device according to claim 1, wherein, The fastening part makes the hardness difference between the fastener and the internal thread greater than Vickers hardness HV62.

4. The eccentric oscillating gear device according to claim 1, wherein, The relationship between the surface roughness MRa of the externally threaded portion after interlocking and tightening and the surface roughness FRa of the internally threaded portion after tightening is as follows: The surface roughness FRa of the internal thread portion is in the range of 0.2 to 1.

0. The ratio RRa = MRa / FRRa is a value within the range of 0.25 to 3.

333. The units for surface roughness MRa and surface roughness FRa are μm.

5. The eccentric oscillating gear device according to claim 4, wherein, In a rectangular coordinate system where the horizontal axis represents the surface roughness FRa of the internal thread and the vertical axis represents the surface roughness MRa of the external thread / the surface roughness FRa:RRa of the internal thread The relationship between the surface roughness MRa of the externally threaded portion after interlocking and tightening and the surface roughness FRa of the internally threaded portion after tightening is as follows: The surface roughness FRa of the internal thread portion is represented by points (FRa, RRa) and the ratio RRa = MRa / FRa, respectively, and these points are set as follows: RRa1 (0.3, 3.333), RRa2 (0.4, 2.500), RRa3 (0.5, 2.000), RRa4 (0.6, 1.667), RRa5 (0.7, 1.429), RRa6 (0.8, 1.250), RRa7 (0.9, 1.111), and RRa8 (1.0, 1.000). The values ​​within the range enclosed by points RRa9 (1.0, 0.500), RRa10 (0.9, 0.556), RRa12 (0.8, 0.250), RRa13 (0.7, 0.286), RRa14 (0.6, 0.333), RRa15 (0.5, 0.400), RRa16 (0.4, 0.500), RRa17 (0.3, 0.667), RRa18 (0.2, 1.000), and RRa19 (0.2, 2.500) are: The units for surface roughness MRa and surface roughness FRa are μm.

6. The eccentric oscillating gear device according to claim 1, wherein, The relationship between the surface roughness MRpk of the externally threaded portion after interlocking and tightening and the surface roughness FRpk of the internally threaded portion after tightening is as follows: The surface roughness FRpk of the internal thread portion is in the range of 0.2 to 0.

6. The ratio RRpk = MRpk / FRpk is a value in the range of 0.4 to 5.

5. The units for surface roughness MRpk and surface roughness FRpk are μm.

7. The eccentric oscillating gear device according to claim 6, wherein, In a Cartesian coordinate system where the horizontal axis represents the surface roughness FRpk of the internal thread and the vertical axis represents the surface roughness MRpk of the external thread / the surface roughness FRpk:RRpk of the internal thread, The relationship between the surface roughness MRpk of the externally threaded portion after interlocking and tightening and the surface roughness FRpk of the internally threaded portion after tightening is as follows: The values ​​are set as follows: FRpk represents the surface roughness of the internal thread portion, and RRpk = MRpk / FRpk represents the values ​​at points (FRpk, RRpk), defined as follows: RRpk1 (0.2, 5.500), RRpk2 (0.3, 3.667), RRpk3 (0.4, 2.750), RRpk4 (0.5, 2.200), RRpk5 (0.6, 1.833), RRpk6 (0.6, 1.000), RRpk7 (0.5, 0.400), RRpk8 (0.4, 0.500), RRpk9 (0.3, 0.667), and RRpk10 (0.2, 1.000). The units for surface roughness MRpk and surface roughness FRpk are μm.

8. The eccentric oscillating gear device according to claim 1, wherein, The relationship between the surface roughness MRv of the externally threaded portion after interlocking and tightening and the surface roughness FRv of the internally threaded portion after tightening is as follows: The surface roughness FRv of the internal thread portion is a value in the range of 0.4 to 1.

1. The ratio RRv = MRv / FRv is a value in the range of 0.364 to 1.

833. The units for surface roughness MRv and surface roughness FRv are μm.

9. The eccentric oscillating gear device according to claim 8, wherein, In a Cartesian coordinate system where the horizontal axis represents the surface roughness FRv of the internal thread and the vertical axis represents the surface roughness MRv of the external thread / the surface roughness FRv:RRv of the internal thread The relationship between the surface roughness MRv of the externally threaded portion after interlocking and tightening and the surface roughness FRv of the internally threaded portion after tightening is as follows: If the surface roughness FRv of the internal thread portion is represented by points (FRv, RRv) and the ratio RRv = MRv / FRv, then the points are set as follows: point RRv1 (0.4, 1.500), point RRv2 (0.5, 1.200), point RRv3 (0.6, 1.833), point RRv4 (0.7, 1.571), point RRv5 (0.8, 1.375), point RRv6 (0.9, 1.222), point RRv7 (1.0, 1.100). The values ​​within the range enclosed by points RRv8 (1.1, 1.000), RRv9 (1.1, 0.364), RRv10 (1.0, 0.400), RRv11 (0.9, 0.444), RRv12 (0.8, 0.500), RRv13 (0.7, 0.571), RRv14 (0.6, 0.667), RRv15 (0.5, 0.800), and RRv16 (0.4, 1.000) are: The units for surface roughness MRv and surface roughness FRv are μm.

10. An eccentric oscillating gear device, wherein, This eccentric oscillating gear device has the following features: case; An internal gear is disposed on the inner circumference of the housing; An external gear that meshes with the internal gear; An eccentric body that causes the external gear to oscillate; The first component is supported on the housing by means of a first bearing; The second component is supported on the housing by means of a second bearing; as well as A fastening part that fastens the first component and the second component in the axial direction of the housing. The fastening part has an internal thread portion formed on the first component and a fastener having an external thread portion. The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener. When the internal thread portion is threaded into the external thread portion, the external thread portion causes the small protrusions on the surface of the thread teeth of the internal thread portion to undergo plastic deformation.

11. A robot, wherein, This robot has the following features: Multiple components, including an arm that is connected to be freely movable; A connecting portion that connects a plurality of said components, including the arm portion, to be rotatable; and An eccentric oscillating gear device is mounted on the connecting part. The eccentric oscillating gear device includes: case; The first component is supported on the housing by means of a first bearing; The second component is supported on the housing by means of a second bearing; as well as A fastening part that fastens the first component and the second component in the axial direction of the housing. The fastening part has: An internal thread portion, formed on the first member; and Fasteners having external threads, The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener. When the internal thread portion is threaded into the external thread portion, the external thread portion causes the small protrusions on the surface of the thread teeth of the internal thread portion to undergo plastic deformation.

12. An industrial machine, wherein, This industrial machinery has the following features: Multiple components, which are interconnected; A connecting part that connects the plurality of said components to allow for free rotation; and An eccentric oscillating gear device is mounted on the connecting part. The eccentric oscillating gear device includes: case; The first component is supported on the housing by means of a first bearing; The second component is supported on the housing by means of a second bearing; as well as A fastening part that fastens the first component and the second component in the axial direction of the housing. The fastening part has: An internal thread portion, formed on the first member; and Fasteners having external threads, The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener. When the internal thread portion is threaded into the external thread portion, the external thread portion causes the small protrusions on the surface of the thread teeth of the internal thread portion to undergo plastic deformation.

13. A method for assembling an eccentric oscillating gear device, wherein the eccentric oscillating gear device outputs a deceleration output by reducing the external rotation, wherein... The eccentric oscillating gear device includes: case; The first component is supported on the housing by means of a first bearing; The second component is supported on the housing by means of a second bearing; as well as A fastening part that fastens the first component and the second component in the axial direction of the housing. In the assembly method of the eccentric oscillating gear device, During the assembly of the eccentric oscillating gear assembly, when fastening the first component and the second component using the fastening part, a preload is applied to the first bearing and the second bearing. The fastening part has: An internal thread portion, formed on the first member; and Fasteners having external threads, The hardness of the fastener is set to Rockwell hardness HRC44 or higher, and the hardness of the internal thread portion is lower than the hardness of the fastener. When the internal thread portion is threaded into the external thread portion, the external thread portion causes the small protrusions on the surface of the thread teeth of the internal thread portion to undergo plastic deformation.

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