reducer

Abstract

A reducer is provided. A reducer (100) according to an aspect of the present application includes: an internal gear (116) having a housing (122) that surrounds a main axis (1La) and a plurality of external pins (117) that are rotatably arranged in pin grooves (116b) provided in an inner periphery of the housing; an external gear (114) that is engaged with the internal gear; an eccentric body (112) that oscillates the external gear; a gear carrier (118, 120) that rotates relative to the housing; and a main bearing (124, 126) having an inner peripheral sliding surface (148) that rotates integrally with the housing and an outer peripheral sliding surface (149) that rotates integrally with the gear carrier. One of the inner peripheral sliding surface and the outer peripheral sliding surface is formed of resin, and the other sliding surface is formed of a heat conductive material having higher wear resistance than the resin.

Description

Technical Field

[0001] This invention relates to a speed reducer. Background Technology

[0002] Conventionally, eccentric oscillating reducers are known to reduce rotational speed between two object-side components at a predetermined reduction ratio. These eccentric oscillating reducers include: an outer cylinder fixed to one object-side component; and a gear carrier disposed within the outer cylinder and fixed to the other object-side component. The gear carrier rotates relative to the outer cylinder by the oscillating rotation of an eccentric gear mounted to the eccentric portion of the crankshaft.

[0003] In recent years, there has been a trend of demanding further miniaturization and weight reduction of robots due to changes in the robot's operating environment. Along with this, there is also a demand for miniaturization and weight reduction of reducers.

[0004] As disclosed in Patent Document 1, in order to make the components of the reducer lighter, for example, a solution of using components formed of resin is conceived.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-17362 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, the technology described in Patent Document 1 has the problem of insufficient lightweighting.

[0010] Furthermore, in the technology described in Patent Document 1, when more resin parts are added to achieve weight reduction, there is a possibility that the incidence of defects may increase due to insufficient strength caused by the resin parts. Moreover, when the temperature rises during the use of the reducer, there is a possibility that defects such as deformation and malfunction may occur due to the resin parts.

[0011] The present invention aims to provide a speed reducer that can simultaneously achieve lightweight and increased rigidity.

[0012] Solution for solving the problem

[0013] (1) A speed reducer according to one embodiment of the present invention comprises: an internal gear having: a housing (equivalent to the internal gear body) surrounding a main shaft; and a plurality of outer pins rotatably disposed in pin grooves located on the inner periphery of the housing; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing having an inner peripheral sliding surface integrally rotating with the housing and an outer peripheral sliding surface integrally rotating with the gear carrier. One of the inner and outer peripheral sliding surfaces is formed of resin, and the other sliding surface is formed of a thermally conductive material with higher wear resistance than the resin.

[0014] According to a technical solution of the present invention, a reducer uses an external pin between the housing and the external gear, thereby maintaining a small and lightweight design while improving rigidity and heat dissipation. Consequently, reducer malfunctions can be suppressed.

[0015] (2) For the reducer described in (1), the main bearing may be configured such that the inner circumferential sliding surface is formed on the inner circumferential surface of the housing, or the outer circumferential sliding surface is formed on the outer circumferential surface of the gear carrier.

[0016] (3) For the reducer described in (2), the gear carrier may also be formed of the resin, and the outer peripheral sliding surface may be formed on the outer peripheral surface of the gear carrier.

[0017] (4) For the reducer described in (3), the inner circumferential sliding surface may also be formed of the thermally conductive material and the inner circumferential sliding surface may be disposed at a position that overlaps with the outer pin in the direction along the main axis.

[0018] (5) A speed reducer according to one embodiment of the present invention comprises: an internal gear having: a housing (equivalent to the internal gear body) surrounding a main axis; and a plurality of outer pins rotatably disposed in pin grooves provided on the inner periphery of the housing; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing having an inner circumferential sliding surface formed on the inner periphery of a metal ring integrally rotating with the housing and an outer circumferential sliding surface formed on the outer circumferential surface of the gear carrier. The housing and the gear carrier are formed of resin. The metal ring and the outer pins are arranged in an overlapping position along the direction of the main axis.

[0019] According to a technical solution of the present invention, a reducer uses an outer pin between the housing and the external gear, and the outer pin and the metal ring are stacked along the main axis. Therefore, it is possible to maintain a small and lightweight state while further improving rigidity. Consequently, it is possible to suppress reducer failure.

[0020] (6) A speed reducer according to one embodiment of the present invention comprises: an internal gear disposed on the inner periphery of a housing surrounding a main shaft; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing having an inner peripheral sliding surface that rotates integrally with the housing and an outer peripheral sliding surface that rotates integrally with the gear carrier. One of the inner and outer peripheral sliding surfaces is formed of resin, and the other sliding surface is formed of a thermally conductive material with higher wear resistance than the resin. At least one of the inner and outer peripheral sliding surfaces is inclined such that its diameter relative to the main shaft increases or decreases in the direction along the main shaft.

[0021] According to a technical solution of the present invention, the speed reducer can increase the contact area of ​​the shaft support surface of the sliding bearing and thus improve the stability of operation.

[0022] (7) For the reducer described in (6), it is also possible that a protrusion is formed on the inner peripheral sliding surface and the outer peripheral sliding surface to serve as a compression allowance.

[0023] (8) For any one of (1) to (7) the reducer may also have grooves formed on the inner and outer peripheral sliding surfaces that are not in communication with the internal space for receiving the external gear.

[0024] (9) A speed reducer according to one embodiment of the present invention comprises: an internal gear disposed on the inner periphery of a housing surrounding a main shaft; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing having an inner circumferential sliding surface formed on the inner circumferential surface of the housing and an outer circumferential sliding surface formed on the outer circumferential surface of the gear carrier. The housing is formed of metal, and the gear carrier is formed of resin. The inner and outer circumferential sliding surfaces are inclined such that their diameter relative to the main shaft increases along the main shaft in a direction away from the external gear. Protrusions forming a compression allowance are formed on the inner and outer circumferential sliding surfaces. Grooves not communicating with the internal space for receiving the external gear are formed on the inner and outer circumferential sliding surfaces.

[0025] According to a technical solution of the present invention, a speed reducer can collect dust, excess grease, etc., in grooves at the inner and outer peripheral sliding surfaces. Therefore, it is possible to prevent dust and the like from affecting the sliding state at the inner and outer peripheral sliding surfaces. Furthermore, it is possible to prevent dust and the like from entering the interior of the speed reducer.

[0026] (10) A speed reducer according to one embodiment of the present invention is an eccentric oscillating type speed reducer that transmits driving force by switching speeds between a first component and a second component at a predetermined speed ratio. It comprises: an eccentric portion; an external gear having a through hole into which the eccentric portion is inserted and having external teeth; a housing configured to be mounted on one of the first component and the second component; a gear carrier configured to be mounted on the other component of the first component and the second component; and a main bearing having an inner circumferential sliding surface that rotates integrally with the housing and an outer circumferential sliding surface that rotates integrally with the gear carrier. The housing has internal teeth that mesh with the external teeth of the external gear. The gear carrier is disposed radially inward of the housing, holding the external gear in place. Due to the oscillation of the external gear as the eccentric portion rotates, the housing and the gear carrier can rotate concentrically relative to each other. One of the inner and outer circumferential sliding surfaces is formed of resin, and the other sliding surface is formed of a thermally conductive material with higher wear resistance than the resin.

[0027] According to a technical solution of the present invention, a reducer uses an external pin between the housing and the external gear, thereby maintaining a small and lightweight design while improving rigidity and heat dissipation. Consequently, reducer malfunctions can be suppressed.

[0028] (11) One embodiment of the present invention provides a speed reducer that is an eccentric oscillating type speed reducer having two or more eccentric bodies and external gears corresponding to each of the eccentric bodies. It comprises: a housing having an internal gear meshing with the external gear on its inner circumference; a gear carrier that rotates relative to the housing and relative to the eccentric bodies; and a main bearing having an inner circumferential sliding surface formed on the inner circumferential surface of the housing and an outer circumferential sliding surface formed on the outer circumferential surface of the gear carrier. One of the inner and outer circumferential sliding surfaces is formed of resin, and the other sliding surface is formed of a thermally conductive material with higher wear resistance than the resin.

[0029] According to a technical solution of the present invention, a reducer uses an external pin between the housing and the external gear, thereby maintaining a small and lightweight design while improving rigidity and heat dissipation. Consequently, reducer malfunctions can be suppressed.

[0030] (12) A speed reducer according to one embodiment of the present invention comprises: an internal gear having: a housing (equivalent to the internal gear body) surrounding a main shaft; and a plurality of outer pins rotatably disposed in pin grooves provided on the inner periphery of the housing; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing disposed such that the outer pins are clamped between an inner peripheral surface integrally rotating with the housing and an outer peripheral surface integrally rotating with the gear carrier. The inner and outer peripheral surfaces are formed of resin and the outer pins are formed of a thermally conductive material with higher wear resistance than the resin, or the outer pins are formed of resin and the inner and outer peripheral surfaces are formed of a thermally conductive material with higher wear resistance than the resin.

[0031] According to a technical solution of the present invention, a reducer uses an external pin between the housing and the external gear, thereby maintaining a small and lightweight design while improving rigidity and heat dissipation. Consequently, reducer malfunctions can be suppressed.

[0032] (13) For the reducer described in (12), it is also possible that an enlarged diameter portion is formed at the end (one end and / or the other end) of the outer pin.

[0033] (14) A speed reducer according to one embodiment of the present invention comprises: an internal gear having: a housing (equivalent to the internal gear body) surrounding a main shaft; and a plurality of outer pins rotatably disposed in pin grooves provided on the inner periphery of the housing; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; a first main bearing disposed such that the outer pins are clamped between an inner circumferential surface integrally rotating with the housing and an outer circumferential surface integrally rotating with the gear carrier; and a second main bearing configured as a crossed roller bearing comprising a plurality of rollers disposed between V-grooves of V-shaped cross sections facing each other. The inner and outer circumferential surfaces are formed of resin and the outer pins are formed of a thermally conductive material with higher wear resistance than the resin, or the outer pins are formed of resin and the inner and outer circumferential surfaces are formed of a thermally conductive material with higher wear resistance than the resin.

[0034] (15) A speed reducer according to one embodiment of the present invention comprises: an internal gear having: a housing (equivalent to the internal gear body) surrounding a main shaft; and a plurality of outer pins rotatably disposed in pin grooves provided on the inner periphery of the housing; an external gear meshing with the internal gear; an eccentric body causing the external gear to oscillate; a gear carrier rotating relative to the housing; and a main bearing disposed such that the outer pins are clamped between an inner peripheral surface integrally rotating with the housing and an outer peripheral surface integrally rotating with the gear carrier. The inner and outer peripheral surfaces are formed of resin. The outer pins are formed of metal. An enlarged diameter portion is formed at the end of the outer pin.

[0035] According to a technical solution of the present invention, the reducer uses an external pin between the housing and the external gear, thereby maintaining a small and lightweight design while improving rigidity and heat dissipation. Therefore, it can suppress reducer malfunctions and improve operational reliability.

[0036] The effects of the invention

[0037] According to the present invention, the following effects are achieved: the rigidity and heat dissipation are improved while maintaining the small and lightweight state, and the operation reliability is improved by suppressing the occurrence of failures. Attached Figure Description

[0038] Figure 1 This is a cross-sectional view along the main axis showing the first embodiment of the reducer of the present invention.

[0039] Figure 2 yes Figure 1 The view along section II-II.

[0040] Figure 3 This is a cross-sectional view along the main axis showing the second embodiment of the reducer of the present invention.

[0041] Figure 4 This is a cross-sectional view along the main axis showing the third embodiment of the reducer of the present invention.

[0042] Figure 5 yes Figure 4 The VV section view in the diagram.

[0043] Figure 6 This is a cross-sectional view along the main axis showing the fourth embodiment of the reducer of the present invention.

[0044] Figure 7 This is an enlarged cross-sectional view of the vicinity of the main bearing in the fifth embodiment of the reducer of the present invention.

[0045] Figure 8This is a cross-sectional view of the housing showing the inner circumferential sliding surface of the main bearing in the sixth embodiment of the reducer of the present invention.

[0046] Figure 9 This is an enlarged cross-sectional view of the housing, which is an example of the relationship between the compression allowance of the inner circumferential sliding surface and the groove in the sixth embodiment.

[0047] Figure 10 This is a cross-sectional view of a housing, illustrating an example of the relationship between the compression allowance of the inner circumferential sliding surface and the groove in the sixth embodiment.

[0048] Figure 11 This is a cross-sectional view along the main axis showing the seventh embodiment of the reducer of the present invention.

[0049] Figure 12 yes Figure 11 The XII-XII section view in the image.

[0050] Figure 13 This is a cross-sectional view along the main axis showing the eighth embodiment of the reducer of the present invention.

[0051] Figure 14 This is a cross-sectional view along the main axis showing the ninth embodiment of the speed reducer of the present invention.

[0052] Figure 15 yes Figure 14 The XV-XV section view in the diagram.

[0053] Figure 16 This is a cross-sectional view along the main axis showing the tenth embodiment of the speed reducer of the present invention.

[0054] Figure 17 This is a cross-sectional view along the main axis showing the 11th embodiment of the speed reducer of the present invention.

[0055] Figure 18 This is a cross-sectional view along the main axis showing the 12th embodiment of the speed reducer of the present invention.

[0056] Figure 19 This is a cross-sectional view along the main axis showing the 13th embodiment of the reducer of the present invention.

[0057] Figure 20 This is a cross-sectional view along the main axis showing the 14th embodiment of the speed reducer of the present invention.

[0058] Explanation of reference numerals in the attached figures

[0059] 100, 200, 300, 400, 500, 600: Reducers; 1La, 2La, 3La, 4La, 5La, 6La: Central axis (main axis); 112, 212, 312, 512, 612: Input shaft (eccentric body); 112a, 212a, 312a, 410a, 410b, 503, 612a: Eccentric part; 114, 214, 314, 414, 416, 514, 614: External gears; 116, 216... 316, 417A, 516, 616, internal gears; 116b, 216b, 316b, 422b, 516b, 616b, pin grooves; 117, 217, 317, 417, 517, 617, external pins (internal gear pins); 118, 218, 318, 404a, 518, 618, first gear carrier (shaft support); 120, 220, 320, 404b, 520, 620, second gear carrier (retaining support); 122, 222, 32 2, 422, 522, 622, housing; 124, 224, 324, 424, 524, 624, main bearing; 126, 226, 326, 426, 526, 626, main bearing; 148, 248, 348, 448, 548, inner circumferential sliding surface; 149, 249, 349, 449, 549, outer circumferential sliding surface; 221, first cover; 223, second cover; 144, 145, 244, 245, 444, 445, 544. 545. Metal ring; 348a, 348b. Protrusions; 360. Groove; 361. Radial groove; 362, 363. Circumferential groove; 404, 519. Gear carrier; 408. Input shaft; 410. Crankshaft (eccentric body); 617b. End face; 617c. Circumferential surface; 617f. Expanded diameter section; 646, 647. Circumferential recess; 648. Inner circumferential surface; 649a. Annular surface; 649b. Outer circumferential surface; 624a. Outer ring; 624b. Inner ring; 624c. Roller. Detailed Implementation

[0060] (First Embodiment)

[0061] Hereinafter, a first embodiment of the reducer of the present invention will be described based on the accompanying drawings.

[0062] Figure 1 This is a cross-sectional view along the main axis of the reducer of this embodiment. Figure 2 yes Figure 1 The figure shows a section view along section II-II. For ease of understanding, the dimensions of the components in each figure are shown at appropriate enlargements or reductions. Parts of components that are not essential to illustrating the embodiments are omitted from the figures.

[0063] exist Figure 1 and Figure 2In the attached diagram, reference numeral 100 indicates a speed reducer. Figure 2 For ease of understanding, only one of the two external gears 114 is shown in the diagram.

[0064] The reducer 100 of this embodiment is an eccentric oscillating type reducer that causes the external gear meshing with the internal gear to oscillate, thereby causing one of the gears, the internal gear and the external gear, to rotate, and outputs the generated rotation component from the output member to the driven device.

[0065] like Figure 1 , Figure 2 As shown, the eccentric oscillating type reducer 100 includes: an input shaft 112, an external gear 114, an internal gear 116, a first gear carrier 118, a second gear carrier 120, a housing 122, a first main bearing 124, a second main bearing 126, an inner pin 140, and a gear carrier pin 138.

[0066] Hereinafter, the direction along the central axis (main axis) 1La of the internal gear 116 will be referred to as the "axial direction," and the circumferential direction and radial direction of the circle centered on the central axis 1La will be designated as "circumferential" and "radial," respectively. For convenience, one side of the axial direction ( Figure 1 The right side of the input is called the input side, and the other side ( Figure 1 The left side of the input is called the inverse input side or the output side.

[0067] Furthermore, in the following description, the first gear carrier 118 and the second gear carrier 120 may be simply referred to as gear carriers 118 and 120. Similarly, the first main bearing 124 and the second main bearing 126 may be simply referred to as main bearings 124 and 126.

[0068] The input shaft 112 rotates about its rotation center line using rotational power input from a drive source. In this embodiment, the reducer 100 is a type of central crankshaft where the rotation center line of the input shaft 112 is located on the same axis as the central axis 1La of the internal gear 116. The drive source can be, for example, a motor, a geared motor, or an engine.

[0069] The input shaft 112 is an eccentric shaft with multiple eccentric portions 112a for oscillating the external gear 114. Such an input shaft (eccentric body) 112 is sometimes referred to as a crankshaft. The core of the eccentric portion 112a is eccentric relative to the rotation center line of the input shaft 112. In this embodiment, two eccentric portions 112a are arranged adjacent to each other on the input shaft 112. The eccentric phases of adjacent eccentric portions 112a are offset by 180°.

[0070] The input side of the input shaft 112 is supported on the second gear carrier 120 by means of an input shaft bearing 134, and the reverse input side is supported on the first gear carrier (shaft support) 118 by means of an input shaft bearing 134. The input shaft 112 is supported so as to be rotatable relative to the first gear carrier 118 and the second gear carrier (retaining support) 120. The structure of the input shaft bearing 134 is not particularly limited; in this example, it is a ball bearing having, for example, spherical rolling elements.

[0071] The internal gear 116 meshes with the external gear 114. The internal gear 116 of this embodiment has: an internal gear body 116a, which is integrated with the housing 122; and an external pin (internal tooth pin) 117, which is disposed in each pin groove 116b, and the pin grooves 116b are formed in the internal gear body 116a in a circumferentially spaced manner.

[0072] The outer pin 117 is a cylindrical or cylindrical pin member that is rotatably supported on the internal gear body 116a. The outer pin 117 constitutes the internal teeth of the internal gear 116. The number of outer pins 117 (the number of internal teeth) of the internal gear 116 is slightly more than the number of external teeth of the external gear 114 (only one more in this example).

[0073] Basically, all the outer pins 117 have the same shape. The diameter of the outer pins 117 is set equally along the entire length of the central axis 1La. All the outer pins 117 are arranged parallel to the central axis 1La. All the outer pins 117 are arranged in the same position in the axial direction and radial direction along the central axis 1La, and are arranged apart from each other in the circumferential direction.

[0074] The internal gear body 116a and housing 122, which are formed as one piece, are made of resin.

[0075] The internal gear body 116a and housing 122 can be made of various resins. For example, in this case, the internal gear body 116a and housing 122 are formed of POM (polyacetal). However, this is not a limitation; for example, the internal gear body 116a and housing 122 can also be formed of resins different from POM, such as PEEK (polyetheretherketone) and PAEK (polyaryletherketones).

[0076] The resin used for the internal gear body 116a, the housing 122, and other constituent components of this embodiment can be a resin containing reinforcing fibers such as glass fiber and carbon fiber, or a resin without reinforcing fibers, or a material formed by impregnating a substrate such as paper or cloth with resin and then laminating it. The resin used for each constituent component of this embodiment can also be a resin mixed with thermally conductive fillers.

[0077] In the reducer 100, the outer pin 117 can also be formed from a raw material with a higher thermal conductivity [W / (m·K)] than the resin of the inner gear body 116a, and with higher wear resistance than the resin of the inner gear body 116a.

[0078] The following examples illustrate thermally conductive materials such as metals, which exhibit higher wear resistance than resins. Furthermore, in this specification, "metal" includes thermally conductive materials with higher wear resistance than the aforementioned resins.

[0079] The raw materials used to form export version 117 can be materials with higher wear resistance and thermal conductivity than the resin of the internal gear body 116a. They can also be metal materials, resins with high thermal conductivity, non-metallic materials, etc. Export version 117 can also be a resin mixed with, for example, carbon nanotubes (CNTs) or boron nitride nanotubes (BNNTs). Figure 1 , Figure 2 The outer pin 117 of this embodiment shown can also be formed of ferrous metals such as bearing steel.

[0080] Outer pin 117 can be either a solid or hollow component. Outer pin 117 can also be a multi-layered component consisting of a core material encased in a surface material. For example, outer pin 117 can also be a component where one of the core material and the surface material is an ferrous metal, and the other is a copper-based or aluminum-based metal. In this case, a balance between mechanical and thermal properties can be achieved. Furthermore, as another example, outer pin 117 can also be a component where one of the core material and the surface material is formed of metal, and the other is formed of resin. Additionally, outer pin 117 can also be formed of sintered metal.

[0081] The external gear 114 is individually provided with corresponding eccentric portions 112a. The external gear 114 is supported on the eccentric portions 112a in a rotatable manner by means of eccentric bearings 130.

[0082] like Figure 2 As shown, on the external gear 114, 10 through holes are formed at equal intervals at positions offset from the central axis of the external gear 114.

[0083] Of the 10 through holes, 3 through holes, centered on the axis of the external gear 114 and arranged at equal intervals of 120 degrees, are designated as gear carrier pin holes 139. Gear carrier pins 138 are inserted into the gear carrier pin holes 139.

[0084] The remaining 7 through holes are designated as internal pin holes 141. Internal pins 140 are inserted into the internal pin holes 141. These gear carrier pin holes 139 and internal pin holes 141 can also be of the same diameter.

[0085] The external gear 114, like the internal gear body 116a, is formed of resin. Various resins can be used for the external gear 114. The external gear 114 is positioned closer to the input shaft 112 than the internal gear body 116a. The external gear 114 is formed of, for example, PEEK. However, it is not limited to this; the external gear 114 may also be formed of a resin different from PEEK, such as POM.

[0086] The gear carrier pin hole 139 and the inner pin hole 141 are circular holes of the same diameter, formed at the same position in the radial direction. Wavy teeth are formed on the outer periphery of the external gear 114. The external gear 114 moves by contacting the wavy teeth with the internal gear 116, thereby oscillating in a plane with its central axis as the normal. A clearance is provided between the inner pin 140 and the inner pin hole 141 to absorb the oscillation component of the external gear 114. The inner pin 140 is in partial contact with the inner wall surface of the inner pin hole 141.

[0087] Gear carriers 118 and 120 are positioned on opposite sides of the external gear 114 along the axial direction. The first gear carrier (shaft support) 118 is positioned on the side of the external gear 114 on the reverse input side. The second gear carrier (retaining support) 120 is positioned on the side of the external gear 114 on the input side.

[0088] The first gear carrier (shaft support) 118 is rotatably supported on the housing 122 by means of the first main bearing 124. The second gear carrier (retaining bracket) 120 is rotatably supported on the housing 122 by means of the second main bearing 126.

[0089] The gear carriers 118 and 120 are generally formed in a disk shape. The first gear carrier 118 supports the input shaft 112 for free rotation via the input shaft bearing 134. The second gear carrier 120 supports the input shaft 112 for free rotation via the input shaft bearing 134.

[0090] The gear carrier pin 138 is connected to the first gear carrier (shaft support) 118 and the second gear carrier (retaining support) 120 by means of bolts 138a.

[0091] The inner pin 140 is connected to the first gear carrier (shaft support) 118 and the second gear carrier (retaining support) 120, for example, by means of a bolt 140a made of ferrous metal.

[0092] The first gear carrier 118 and the second gear carrier 120 are connected by a gear carrier pin 138 and an inner pin 140. The gear carrier pin 138 and the inner pin 140 pass through the external gear 114 along the axial direction at a position offset radially relative to the shaft of the external gear 114.

[0093] In this example, the gear carrier pin 138 and the inner pin 140 are provided independently of the gear carriers 118 and 120. However, this is not a limitation; for example, a portion of the gear carrier pin 138 and the inner pin 140 may also be formed as part of the gear carriers 118 and 120.

[0094] Either the first gear carrier 118 or the housing 122 functions as an output member that outputs rotational power to the driven device, while the other functions as a fixed member that is fixed to an external member used to support the reducer 100.

[0095] The output component is rotatably supported on the fixed component by means of main bearings 124 and 126. The driven component driven by the reducer 100 is connected to the end face of the first gear carrier 118 on the opposite input side by bolts or the like. Alternatively, the driven component driven by the reducer 100 can also be connected to the outer peripheral flange of the housing 122 by bolts or the like.

[0096] The housing 122 is generally formed as a hollow cylinder. An internal gear 116 is provided on the inner periphery of the housing 122. A flange or the like may also be provided on the outer periphery of the housing 122. A first metal ring 144 located on the reverse input side of the housing 122 and a second metal ring 145 located on the input side of the housing 122 are provided. The first metal ring 144 and the second metal ring 145 are fixedly integrated with the housing 122.

[0097] In addition, the first metal ring 144 and the second metal ring 145 can also be fixed to the housing 122 using a plurality of bolts arranged in the circumferential direction.

[0098] In the following description, the first metal ring 144 and the second metal ring 145 may be referred to simply as metal rings 144 and 145.

[0099] The housing 122 has a recess for receiving the first metal ring 144. The first metal ring 144 protrudes relative to the recess in the axial direction. The first metal ring 144 functions as the outer ring of the first main bearing 124. The outer periphery of the first metal ring 144 may also be flush with the outer periphery of the housing 122.

[0100] A first metal ring 144, functioning as the outer ring of the first main bearing 124, is located on the output side of the housing 122. The first metal ring 144 is exposed on the output side of the housing 122. A portion of the first metal ring 144 that protrudes from the recess of the housing 122 in the axial direction forms an inner circumferential sliding surface 148, which functions as the outer ring. The inner circumferential sliding surface 148 contacts the first gear carrier (shaft support) 118. The first metal ring 144 is fixed to the housing 122 using, for example, a clearance fit, an interference fit, or a transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0101] The housing 122 has a recess for receiving the second metal ring 145. The second metal ring 145 protrudes relative to the recess in the axial direction. The second metal ring 145 functions as the outer ring of the second main bearing 126. The outer periphery of the second metal ring 145 may also be flush with the outer periphery of the housing 122.

[0102] A second metal ring 145, functioning as the outer ring of the second main bearing 126, is located on the input side of the housing 122. The second metal ring 145 is exposed on the input side of the housing 122. A portion of the second metal ring 145 that protrudes axially relative to the recess in the housing 122 forms an inner circumferential sliding surface 148, which functions as the outer ring. The inner circumferential sliding surface 148 contacts the second gear carrier (retaining bracket) 120. The second metal ring 145 is fixed to the housing 122 using, for example, a clearance fit, an interference fit, or a transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0103] The first main bearing 124 is disposed between the first gear carrier 118 and the housing 122. The second main bearing 126 is disposed between the second gear carrier 120 and the housing 122. Figure 1 , Figure 2 In the embodiment shown, the main bearings 124 and 126 are configured as sliding bearings.

[0104] The main bearings 124 and 126 have an inner circumferential sliding surface 148 that functions as part of the outer ring and an outer circumferential sliding surface 149 that functions as part of the inner ring.

[0105] The outer peripheral sliding surface 149 is provided on the outer peripheral surface of the gear carriers 118 and 120. The inner peripheral sliding surface 148 is provided on the inner peripheral surface of the metal rings 144 and 145.

[0106] The inner circumferential sliding surface 148, which functions as part of the outer ring of the main bearings 124 and 126, is formed from a raw material with a higher thermal conductivity than the resin of the gear carriers 118 and 120, which forms the outer circumferential sliding surface 149, which also functions as part of the inner ring.

[0107] In the main bearings 124 and 126, the raw materials for forming the metal rings 144 and 145, which function as outer rings, can be materials with higher thermal conductivity and higher strength than the resins of the gear carriers 118 and 120, which function as inner rings. For example, the raw materials for forming the metal rings 144 and 145 can also be metallic or non-metallic materials. In this embodiment, the metal rings 144 and 145 can also be formed from copper-based or aluminum-based metals, bearing steel, or other ferrous metals.

[0108] Metal rings 144 and 145 can be solid or hollow components. They can also be multi-layered components formed by wrapping a core material with a surface material forming the inner circumferential sliding surface 148. For example, metal rings 144 and 145 can also be made of an iron-based metal and a copper-based or aluminum-based metal, where one of the core material and the surface material is iron. As another example, metal rings 144 and 145 can also be formed from sintered metal.

[0109] In the main bearings 124 and 126, the inner circumferential sliding surface 148 and the outer circumferential sliding surface 149 are located radially outward from the outer pin 117.

[0110] like Figure 1 As shown, both the first metal ring 144 and the second metal ring 145 are arranged to overlap with the outer pin 117 in the radial direction. This allows strength to be maintained along the entire length of the housing 122.

[0111] The inner pin 140 is inserted into the inner pin hole 141 formed in the external gear 114 with a gap. One end of the inner pin 140 is embedded in the recess 118a of the first gear carrier 118, and the other end is embedded in the recess 120b of the second gear carrier 120. The inner pin 140 is fixed to the recesses 118a and 120b by bolts 140a. Alternatively, the inner pin 140 can be pressed into the recesses 118a and 120b. In this case, it is not necessary to fix the inner pin 140 by bolts or the like.

[0112] The inner pin 140 contacts a portion of the inner pin hole 141 formed in the outer gear 114. Thus, the inner pin 140 constrains the rotation of the outer gear 114, allowing only oscillation. The inner pin 140 functions as a connecting member facilitating the transmission of power between the first gear carrier 118 and the second gear carrier 120 and the outer gear 114.

[0113] The gear carrier pin 138 is inserted into the gear carrier pin hole 139 formed in the external gear 114 with a gap. One end of the gear carrier pin 138 is embedded in the recess 118c of the first gear carrier 118, and the other end is embedded in the recess 120c of the second gear carrier 120. The gear carrier pin 138 is fixed to the recesses 118c and 120c by bolts 138a. Alternatively, the gear carrier pin 138 can be pressed into the recesses 118c and 120c. In this case, it is not necessary to fix it with bolts or the like.

[0114] The gear carrier pin 138 does not contact the gear carrier pin hole 139 of the external gear 114. Therefore, the gear carrier pin 138 does not contribute to the constraint of the rotation of the external gear 114. The gear carrier pin 138 functions only as a connecting member that facilitates the connection between the first gear carrier 118 and the second gear carrier 120.

[0115] As a speed reducer, its applications have expanded to collaborative robots operating near humans. To broaden its applications, lightweight and low-noise reduction of the speed reducer is desired. Conventional speed reducers are constructed from ferrous metal components; to achieve weight reduction, it is desirable to form components from low-density raw materials. Resin and the like are preferred materials for this purpose.

[0116] On the other hand, if the constituent components are made of resin, it is believed that the temperature will rise due to reduced heat dissipation, resulting in a shorter lifespan. Therefore, it is desirable to select the raw materials used to form each constituent component while considering both lightweighting and heat dissipation. At this point, it is necessary to avoid a decrease in strength resulting from lightweighting.

[0117] In the reducer 100, heat generation is often significant within its interior, particularly around the main bearings 124 and 126, which are configured as sliding bearings. Furthermore, heat generation is often significant around the input shaft 112, which rotates at a relatively high speed. Moreover, without maintaining sufficient strength for the inner pin 140 and the outer gear 114, there is a possibility of malfunction in the reducer 100.

[0118] Thus, with limited heat dissipation from the internal components to the external components, the temperature of the reducer rises. If the temperature increases, the stiffness and strength of the resin components decrease drastically. Therefore, if this condition is maintained and the reducer continues to be used, the likelihood of malfunction is high.

[0119] Therefore, for components that move relative to each other, when one component is made of resin, it is desirable that the other component be made of a material with higher wear resistance and thermal conductivity [W / (m·K)] than the raw material of the resin component. In this case, compared to the case of lower thermal conductivity, heat dissipation from internally generated heat to the outside can be improved. At the same time, compared to the case of lower wear resistance, the component life can be extended.

[0120] The raw material for forming the inner peripheral sliding surface 148, which functions as the outer ring, can be a raw material with higher wear resistance and thermal conductivity than the resin of the inner gear body 116a, which functions as the inner ring. Alternatively, it can be a metallic material, a non-metallic material, or a raw material with high thermal conductivity.

[0121] The first metal ring 144 and the second metal ring 145, as well as the outer pin 117, forming the inner circumferential sliding surface 148 of this embodiment, can be formed from ferrous metals such as bearing steel, aluminum metals, light metals such as aluminum, magnesium, beryllium, and titanium, or composite materials thereof. Alternatively, the first metal ring 144 and the second metal ring 145, as well as the outer pin 117, can also be formed from ceramics or the like. Furthermore, the gear carriers 118 and 120 are formed from resin, thereby achieving a balance between lightweighting and mechanical strength in the reducer 100.

[0122] The high-speed rotation before deceleration is input to the input shaft 112 and the input shaft bearing 134, which is located between the first gear carrier 118 and the input shaft 112. Therefore, if the temperature rise of the input shaft 112 and the input shaft bearing 134 is relatively large and their heat resistance is low, the permissible input speed will decrease. Therefore, the input shaft bearing 134, the input shaft 112, and the eccentric bearing 130 can also be made of metals such as ferrous metals. In this case, the decrease in the permissible input speed can be suppressed.

[0123] Furthermore, since a large torsional stress is applied to the input shaft 112, it is desirable that the input shaft 112 be formed of a material with a higher stiffness than the first gear carrier 118. The input shaft 112 may also be formed of, for example, aluminum or a ferrous metal with a higher torsional strength than aluminum. As a ferrous metal, carbon steel, bearing steel, stainless steel, etc., can be used depending on the desired properties.

[0124] To ensure the connection strength between the first gear carrier 118 and the second gear carrier 120, it is desirable that the gear carrier pin 138 has high rigidity. For this reason, the gear carrier pin 138 can also be made of metal. In this example, the gear carrier pin 138 is made of a metal such as aluminum, which has higher wear resistance and thermal conductivity than resin.

[0125] Explain the operation of the reducer 100 configured as described above.

[0126] If rotational power is transmitted from the drive unit to the input shaft 112, the eccentric portion 112a of the input shaft 112 rotates about the rotation center line (central axis 1La) passing through the input shaft 112. As a result, the external gear 114 oscillates using the eccentric portion 112a. The external gear 114 oscillates by rotating its own shaft about the rotation center line of the input shaft 112. As the external gear 114 oscillates, the meshing position of the external gear 114 and the outer pin 117 of the internal gear 116 shifts sequentially. Consequently, for each revolution of the input shaft 112, the rotation of one of the gears, the external gear 114 and the internal gear 116, is equivalent to the difference between the number of teeth on the external gear 114 and the number of outer pins 117 on the internal gear 116.

[0127] In this embodiment, due to the rotation of the external gear 114, a decelerated rotation is output from the first gear carrier 118 or the housing 122.

[0128] In the reducer 100 of this embodiment, the first metal ring 144 and the second metal ring 145 are used as the first main bearing 124 and the second main bearing 126, and the first gear carrier 118 and the second gear carrier 120, which constitute the main weight of the reducer 100, are made of resin, thus achieving weight reduction.

[0129] In the reducer 100 of this embodiment, the metal rings 144 and 145 forming the inner circumferential sliding surface 148 are formed from a raw material that has wear resistance relative to the resin forming the outer circumferential sliding surface 149 of the gear carrier 118 and 120, and has a higher thermal conductivity than the resin of the gear carrier 118 and 120. Therefore, internal heat can be dissipated more efficiently by means of the metal rings 144 and 145 and the outer pin 117. As a result, the rise in internal temperature can be further suppressed.

[0130] In this embodiment, the reducer 100, as described above, is configured such that the first metal ring 144 and the second metal ring 145 are radially stacked with the outer pin 117. This maintains strength along the entire length of the housing 122 in the axial direction. Consequently, deformation of the housing 122, deformation of the gear carriers 118 and 120, and malfunction of the external gear 114 can be prevented. Therefore, sufficient strength can be maintained.

[0131] In this embodiment, the outer pin 117 is made of metal or the like. This prevents malfunction of the outer gear 114 and maintains sufficient strength.

[0132] Furthermore, for the main bearings 124 and 126, the inner circumferential sliding surface 148 and the outer circumferential sliding surface 149 are not stacked in the axial direction, but are arranged in a substantially continuous manner in the axial direction. This allows for the reduction of the thickness of the reducer 100 while maintaining its strength. In other words, it enables the reduction of the size of the reducer 100 in the direction of its central axis 1La, thus achieving miniaturization.

[0133] The inner circumferential sliding surfaces 148 of the first metal ring 144 and the second metal ring 145 are located radially close to the outer pin 117. Therefore, heat transferred from the main bearings 124 and 126, which are sliding bearings, to the first metal ring 144 and the second metal ring 145 can be dissipated to the outside, thus improving heat dissipation.

[0134] There is a possibility that the resin may melt on the surface of the inner peripheral sliding surface 148 and the outer peripheral sliding surface 149 due to excessive temperature rise, or stick together, causing malfunction. However, since heat dissipation is improved in this embodiment, heat will not accumulate in the reducer 100, thus preventing malfunctions.

[0135] Furthermore, the outer pin 117 is made of metal or the like, which prevents heat loss from the vicinity of the main bearings 124 and 126, thus preventing a localized temperature rise. Consequently, the heat dissipation of the reducer 100 is improved.

[0136] Meanwhile, since the main bearings 124 and 126 are constructed using metal rings 144 and 145 and gear carriers 118 and 120, the number of heavier components such as metal can be reduced compared to structures such as ball bearings and roller bearings. Therefore, further weight reduction can be achieved while maintaining the structural reliability of the reducer 100 and ensuring good heat dissipation.

[0137] (Second Implementation)

[0138] The second embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0139] Figure 3 This is a cross-sectional view along the main axis of the reducer according to this embodiment. In this embodiment, the difference from the first embodiment lies in the points related to the main bearing; other structures corresponding to those in the first embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0140] The reducer 100 in this embodiment, such as Figure 3 As shown, the first metal ring 144 of the first main bearing 124 is disposed on the first gear carrier (shaft support) 118. The first metal ring 144 has an outer peripheral sliding surface 149 of the main bearing 124 formed on its outer periphery.

[0141] The first gear carrier (shaft support) 118 is provided with a recess for receiving the first metal ring 144. The first metal ring 144 is arranged adjacent to the outer pin 117 in the axial direction. In the first gear carrier (shaft support) 118, the first metal ring 144 functions as the inner ring of the first main bearing 124. The outer periphery of the first metal ring 144 may also be flush with the outer periphery of the first gear carrier (shaft support) 118.

[0142] A first metal ring 144, functioning as the inner ring of the first main bearing 124, is located on the input side of the first gear carrier (shaft support) 118. The outer peripheral portion of the first metal ring 144, flush with the outer periphery of the first gear carrier (shaft support) 118, forms an outer peripheral sliding surface 149, which also functions as the inner ring. The outer peripheral sliding surface 149 of the first metal ring 144 contacts the housing 122. The first metal ring 144 is fixed to the first gear carrier (shaft support) 118 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0143] The inner peripheral surface of the housing 122 that contacts the outer peripheral sliding surface 149 forms an inner peripheral sliding surface 148 that functions as the outer ring of the first main bearing 124. Therefore, the outer ring of the first main bearing 124 is designed to be integral with the housing 122.

[0144] Similarly, in this embodiment, the reducer 100, such as Figure 3 As shown, the second metal ring 145 of the second main bearing 126 is disposed on the second gear carrier (retaining bracket) 120. The second metal ring 145 has an outer peripheral sliding surface 149 of the main bearing 126 formed on its outer periphery.

[0145] The second gear carrier (retaining bracket) 120 is provided with a recess for receiving the second metal ring 145. The second metal ring 145 is arranged adjacent to the outer pin 117 in the axial direction. In the second gear carrier (retaining bracket) 120, the second metal ring 145 functions as the inner ring of the second main bearing 126. The outer periphery of the second metal ring 145 may also be flush with the outer periphery of the second gear carrier (retaining bracket) 120.

[0146] A second metal ring 145, functioning as the inner ring of the second main bearing 126, is located on the output side of the second gear carrier (retaining bracket) 120. The outer peripheral portion of the second metal ring 145, flush with the outer periphery of the second gear carrier (retaining bracket) 120, forms an outer peripheral sliding surface 149, which functions as the inner ring. The outer peripheral sliding surface 149 of the second metal ring 145 contacts the housing 122. The second metal ring 145 is fixed to the second gear carrier (retaining bracket) 120 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0147] The inner peripheral surface of the housing 122 that contacts the outer peripheral sliding surface 149 forms an inner peripheral sliding surface 148 that functions as the outer ring of the second main bearing 126. Therefore, the outer ring of the second main bearing 126 is designed to be integral with the housing 122.

[0148] In addition, the metal rings 144 and 145 of the main bearings 124 and 126 can also be configured to cover the entire outer periphery of the gear carriers 118 and 120 from the radially outer side.

[0149] exist Figure 3 In the reducer 100 shown in this embodiment, the inner peripheral sliding surface 148 and the outer peripheral sliding surface 149 are also formed of resin and metal, respectively. Therefore, it can achieve the same effect as the first embodiment.

[0150] (Third Implementation)

[0151] The third embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0152] Figure 4 This is a cross-sectional view along the main axis direction of the reducer in this embodiment. Figure 5 yes Figure 4 The VV section view in the diagram. Figure 4 and Figure 5 In the attached diagram, reference numeral 200 indicates a speed reducer.

[0153] The reducer 200 of this embodiment is an eccentric oscillating type reducer: by oscillating the external gear meshing with the internal gear, one of the internal gear and the external gear rotates, and the rotation component generated therefrom is output from the output member to the driven device.

[0154] In this embodiment, the reducer 200, such as Figure 4 , Figure 5 As shown, the two external gears 214 are combined with each other at a phase difference of 180 degrees, which is different from the first embodiment, but the other structures are the same.

[0155] The reducer 200 of this embodiment includes: an input shaft 212, an external gear 214, an internal gear 216, a first gear carrier 218, a second gear carrier 220, a housing 222, a first main bearing 224, a second main bearing 226, an inner pin 240, and a gear carrier pin 238.

[0156] Hereinafter, the direction along the central axis 2La of the internal gear 216 will be referred to as the "main axis direction," and the circumferential direction and radial direction of the circle centered on the central axis 2La will be designated as "circumferential" and "radial," respectively. Furthermore, for convenience, one side of the axis direction ( Figure 4 The right side of the input is called the input side, and the other side ( Figure 4 The left side of the input is called the reverse input side.

[0157] In the following description, the first gear carrier 218 and the second gear carrier 220 may be referred to simply as gear carriers 218 and 220. Similarly, the first main bearing 224 and the second main bearing 226 may be referred to simply as main bearings 224 and 226.

[0158] The input shaft 212 rotates around its rotation center line using rotational power input from a drive unit (not shown). In this embodiment, the reducer 200 is a type of central crankshaft where the rotation center line of the input shaft 212 is located on the same axis as the central axis 2La of the internal gear 216. The drive unit is, for example, a motor, a geared motor, or an engine.

[0159] In this embodiment, the input shaft 212 is an eccentric shaft having multiple eccentric portions 212a for oscillating the external gear 214. Such an input shaft (eccentric body) 212 is sometimes referred to as a crankshaft. The core of the eccentric portion 212a is eccentric relative to the rotation center line of the input shaft 212. In this embodiment, two eccentric portions 212a are arranged adjacent to each other. The eccentric phases of adjacent eccentric portions 212a are offset by 180°.

[0160] The input side of the input shaft 212 is supported on the second housing 223 by means of an input shaft bearing 234, and the reverse input side is supported on the first gear carrier 218 by means of an input shaft bearing 234. That is, the input shaft 212 is supported so as to be freely rotatable relative to the first gear carrier 218 and the second housing 223. The structure of the input shaft bearing 234 is not particularly limited, but in this example it is a ball bearing with spherical rolling elements. Preload can also be applied to the input shaft bearing 234, but in this example no preload is applied.

[0161] The internal gear 216 meshes with the external gear 214. The internal gear 216 of this embodiment has: an internal gear body 216a, which is integrated with the housing 222; and an external pin (internal tooth pin) 217, which is disposed in each pin groove 216b, and the pin grooves 216b are formed in the internal gear body 216a in a circumferentially spaced manner.

[0162] The outer pin 217 is a cylindrical pin member that is rotatably supported on the internal gear body 216a. The outer pin 217 constitutes the internal teeth of the internal gear 216. The number of outer pins 217 (the number of internal teeth) of the internal gear 216 is slightly more than the number of external teeth of the external gear 214 (only one more in this example).

[0163] The internal gear body 216a is formed of resin. Various resins can be used for the internal gear body 216a. In this embodiment, the internal gear body 216a is formed of, for example, POM (polyacetal). However, it is not limited to this; the internal gear body 216a may also be formed of resins different from POM, such as PEEK (polyetheretherketone) or PAEK (polyaryletherketones).

[0164] The resin used in the internal gear body 216a and other constituent components of this embodiment can be a resin containing reinforcing fibers such as glass fiber and carbon fiber, or a resin without reinforcing fibers, or a material formed by impregnating a substrate such as paper or cloth with resin and then laminating it.

[0165] In particular, the resin used in each component of this embodiment can be a resin mixed with a thermally conductive filler. Examples of thermally conductive fillers include, for example, nanoscale fillers, ceramic powders such as alumina and aluminum nitride, and metal powders such as aluminum, copper, and graphite.

[0166] In the reducer 200, heat generation is often significant, particularly around the input shaft 212 which rotates at relatively high speeds. With low heat dissipation from the internally generated area, the temperature of the reducer 200 rises considerably. As the temperature increases, the strength of the resin components decreases sharply. Therefore, if continued use under these conditions, the likelihood of breakage is high. Thus, for meshing gear pairs, when one gear is made of resin, it is desirable that the other gear be formed from a material with a higher thermal conductivity [W / (m·K)] than the resin component.

[0167] Therefore, in the eccentric oscillating type reducer 200, the outer pin 217 is formed from a raw material with a higher thermal conductivity than the resin of the internal gear body 216a. In this case, compared to the case where the outer pin 217 has a lower thermal conductivity, heat dissipation performance, which allows heat generated internally to be dissipated to the outside, is improved.

[0168] The raw material used to form the outer pin 217 can be a material with a higher thermal conductivity than the resin of the internal gear body 216a, and can also be a metal material, a resin with high thermal conductivity, or a non-metallic material. Examples of resins with high thermal conductivity include resins mixed with thermally conductive fillers. The outer pin 217 can also be a resin mixed with, for example, carbon nanotubes (CNTs) or boron nitride nanotubes (BNNTs). In this embodiment, the outer pin 217 is formed from an ferrous metal such as bearing steel.

[0169] Outer pin 217 can be either a solid or hollow component. Outer pin 217 can also be a multi-layered component consisting of a core material encased in a surface material. As an example, outer pin 217 can also be a component where one of the core material and the surface material is an ferrous metal, and the other is a copper-based or aluminum-based metal. In this case, a balance between mechanical and thermal properties can be achieved. Furthermore, as another example, outer pin 217 can also be a component where one of the core material and the surface material is formed of metal, and the other is formed of resin. Moreover, outer pin 217 can also be formed of sintered metal.

[0170] External gears 214 are individually provided on multiple eccentric portions 212a. External gears 214 are rotatably supported on eccentric portions 212a by means of eccentric bearings 230. On external gears 214, 12 through holes are formed at equal intervals at positions offset relative to the axis of external gears 214.

[0171] Of the 12 through holes, three through holes centered on the axis of the external gear 214 and arranged at equal intervals of 120 degrees are designated as gear carrier pin holes 239. Gear carrier pins 238 are inserted into the gear carrier pin holes 239.

[0172] The remaining nine through holes are designated as internal pin holes 241. Internal pins 240 are inserted into the internal pin holes 241. In this embodiment, the diameter of the gear carrier pin hole 239 is larger than the diameter of the internal pin hole 241. However, this is not a limitation; the gear carrier pin hole 239 and the internal pin hole 241 may also have the same diameter.

[0173] The external gear 214 is formed of resin. Various resins can be used for the external gear 214. In particular, since the external gear 214 is located near the input shaft 212 where the temperature rises significantly, it can also be formed of a resin with a higher heat resistance temperature than the internal gear body 216a. For this reason, the external gear 214 is formed of, for example, PEEK. However, it is not limited to this; the external gear 214 can also be formed of a resin different from PEEK, such as POM.

[0174] The gear carrier pin hole 239 and the inner pin hole 241 are arranged in the same position in the radial direction and are formed into a circle. Wavy teeth are formed on the outer periphery of the external gear 214. The wavy teeth move while contacting the internal gear 216, causing the external gear 214 to oscillate in a plane with its axis as the normal. A clearance is provided between the inner pin 240 and the inner pin hole 241 to absorb the oscillation component of the external gear 214. The inner pin 240 is in partial contact with the inner wall surface of the inner pin hole 241.

[0175] Gear carriers 218 and 220 are disposed on the side of the external gear 214 along its axial direction. The first gear carrier (shaft support) 218 ​​is disposed on the side of the external gear 214 on the reverse input side. The second gear carrier (retaining support) 220 is disposed on the side of the external gear 214 on the input side. The first gear carrier 218 and the second gear carrier 220 are rotatably supported on the housing 222 by means of the first main bearing 224 and the second main bearing 226. The gear carriers 218 and 220 are generally formed in a disc shape.

[0176] The first gear carrier 218 supports the input shaft 212 for free rotation via the input shaft bearing 234. The second gear carrier 220 may also be configured to support the input shaft 212 via the input shaft bearing 234, but in this embodiment, neither the input shaft bearing 234 nor the input shaft 212 is supported.

[0177] The first gear carrier 218 and the second gear carrier 220 are connected by a gear carrier pin 238 and an inner pin 240. The gear carrier pin 238 and the inner pin 240 pass through a plurality of external gears 214 along the axial direction at a position offset radially relative to the shaft core of the external gears 214. In this embodiment, the gear carrier pin 238 and the inner pin 240 are provided independently of the gear carriers 218 and 220. However, this is not a limitation; for example, a portion of the gear carrier pin 238 and the inner pin 240 may also be formed integrally as part of the gear carriers 218 and 220.

[0178] One of the first gear carrier 218 and the housing 222 functions as an output member that outputs rotational power to the driven device, while the other functions as a fixed member that is fixed to an external member that supports the reducer 200. The output member is rotatably supported on the fixed member by means of the main bearings 224 and 226.

[0179] In this embodiment, the output component is the first gear carrier 218, and the fixed component is the housing 222. The driven component 250, driven by the reducer 200, is connected to the end face of the first gear carrier 218 on the opposite input side by bolts 250b. In this embodiment, the bolts 250b may also be made of ferrous metals.

[0180] The housing 222 is generally formed as a hollow cylinder. An internal gear 216 is provided on the inner periphery of the housing 222. A flange or the like may also be provided on the outer periphery of the housing 222, but no flange is provided in this example. A first cover 221 covering the reverse input side of the housing 222 and a second cover 223 covering the input side of the housing 222 are provided on the housing 222. The first cover 221 and the second cover 223 are fixed to the housing 222 by a plurality of bolts arranged in the circumferential direction.

[0181] The housing 222 has a recess on the input side for receiving the outer ring of the first main bearing 224. The first cover 221 has a recess on the reverse input side for receiving a portion of the outer ring of the first main bearing 224. The outer ring of the first main bearing 224 is supported by being sandwiched between the housing 222 and the first cover 221 in the axial direction.

[0182] The housing 222 has a recess for receiving the outer ring of the second main bearing 226 on the reverse input side. The second cover 223 has a recess for receiving a portion of the input side of the outer ring of the second main bearing 226. The outer ring of the second main bearing 226 is supported by being sandwiched between the housing 222 and the second cover 223 in the axial direction. The second cover 223 also has a recess for receiving the outer ring of the input shaft bearing 234 on the input side. In other words, the second cover 223 supports the input side of the input shaft 212 for free rotation by means of the input shaft bearing 234.

[0183] The first main bearing 224 is disposed between the first gear carrier 218 and the housing 222. The second main bearing 226 is disposed between the second gear carrier 220 and the housing 222. In this embodiment, the main bearings 224 and 226 each have metal rings 244 and 245 forming an inner circumferential sliding surface 248. The metal rings 244 and 245 support the gear carriers 218 and 220 for free rotation.

[0184] Main bearings 224 and 226 are configured as sliding bearings. Main bearings 224 and 226 have metal rings 244 and 245 forming an inner circumferential sliding surface 248 that functions as an outer ring, and an outer circumferential sliding surface 249 that functions as an inner ring. The outer circumferential sliding surface 249 is provided on the outer circumferential surface of gear carriers 218 and 220. The metal rings 244 and 245, which function as outer rings, are fixed to the housing 222 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates. Preload can be applied to the main bearings 224 and 226, but in this example, no preload is applied.

[0185] In this embodiment, the metal rings 244 and 245, which function as the outer rings of the main bearings 224 and 226, are formed from a raw material with a higher thermal conductivity than the resin of the internal gear body 216a. Furthermore, the metal rings 244 and 245 are in contact with the outer pin 217 in the axial direction. Figure 4 As shown, the ends of metal rings 244 and 245 can also be configured to be in direct contact with the end of outer pin 217.

[0186] However, this is not a limitation. The ends of the metal rings 244 and 245 and the end of the outer pin 217 can also be configured to contact each other in the axial direction with a spacer. This spacer is made of a material with a higher thermal conductivity than the resin of the internal gear body 216a. With this configuration, the heat transferred to the outer pin 217 is dissipated via the metal rings 244 and 245 to the gear carriers 218 and 220, the housing 222, etc., thus improving heat dissipation. Furthermore, the heat transferred to the first gear carrier 218 is dissipated to the outside via the driven member 250, further improving heat dissipation.

[0187] The raw materials used to form the metal rings 244 and 245 and the outer pin 217 can be materials with a higher thermal conductivity than the resin of the internal gear body 216a, or they can be metallic materials, highly thermally conductive resins, or non-metallic materials. In this embodiment, the metal rings 244 and 245 and the outer pin 217 can also be formed from ferrous metals such as bearing steel.

[0188] The raw material for forming the first gear carrier 218 can be a material with a higher thermal conductivity than the resin of the internal gear body 216a, or it can be a metal, a resin with high thermal conductivity, or a non-metallic material. From the viewpoint of balancing lightweight and mechanical strength, the first gear carrier 218 can also be formed from lightweight metals (metals with a specific gravity of 4 to 5 or less), such as aluminum, magnesium, beryllium, and titanium, or composite materials thereof. In this embodiment, the first gear carrier 218 is formed from an aluminum-based metal. In this case, the first gear carrier 218 can be formed from a metal material with a specific gravity lower than that of the input shaft 212.

[0189] The second gear carrier 220 can be formed from metal or various resins. In this embodiment, the second gear carrier 220 is formed from, for example, POM. In this case, the second gear carrier 220 can be made lightweight.

[0190] To reduce heat conduction from the input shaft bearing 234, the second gear carrier 220 is not in direct contact with the input shaft bearing 234, but is positioned with a gap between them. Furthermore, the second gear carrier 220 can also be formed from a raw material with a higher thermal conductivity than the resin of the internal gear body 216a. In this case, heat dissipation can be further improved.

[0191] The inner pin 240 is inserted into the inner pin hole 241 formed through the external gear 214 with a gap. One end of the inner pin 240 is embedded in the recess 218a of the first gear carrier 218, and the other end is embedded in the recess 220b of the second gear carrier 220. The inner pin 240 is pressed into the recesses 218a and 220b, but is not fixed by bolts or the like. The inner pin 240 contacts a portion of the inner pin hole 241 formed in the external gear 214. Thus, the inner pin 240 restricts the rotation of the external gear 214, allowing only oscillation. The inner pin 240 functions as a connecting member that facilitates the transmission of power between the first gear carrier 218 and the second gear carrier 220 and the external gear 214.

[0192] The gear carrier pin 238 is inserted into the gear carrier pin hole 239 formed in the external gear 214 with a gap. One end of the gear carrier pin 238 is embedded in the recess 218c of the first gear carrier 218, and the other end is embedded in the recess 220c of the second gear carrier 220. The gear carrier pin 238 is pressed into the recesses 218c and 220c and is not fixed by bolts or the like. The gear carrier pin 238 is surrounded by a tubular spacer 237.

[0193] One end of the spacer 237 contacts the first gear carrier 218, and the other end contacts the second gear carrier 220. The spacer 237 functions as a spacer to maintain an appropriate axial distance between the first gear carrier 218 and the second gear carrier 220. The gear carrier pin 238 and the spacer 237 do not contact the gear carrier pin hole 239 of the external gear 214 and do not contribute to the rotation constraint of the external gear 214. The gear carrier pin 238 functions only as a connecting member that facilitates the connection between the first gear carrier 218 and the second gear carrier 220.

[0194] It is desirable to select materials for the constituent components used in this embodiment, taking into account lightweight design and heat dissipation. In recent years, the applications of speed reducers have expanded to collaborative robots and the like that operating near humans. Therefore, lightweight and low-noise speed reducers are desirable. Conventional speed reducers consist of constituent components formed from ferrous metals; for lightweight purposes, it is desirable to form these components from low-density raw materials. Resin and the like are preferred as such materials. On the other hand, if the constituent components are made of resin, it is believed that the temperature will rise due to reduced heat dissipation, resulting in a shorter lifespan.

[0195] The high-speed input shaft 212 and the input shaft bearing 234 are located between the first gear carrier 218 and the input shaft 212 before deceleration. Therefore, when the input shaft 212 and the input shaft bearing 234 experience a large temperature rise and low heat resistance, the permissible input speed decreases. Therefore, the input shaft bearing 234, the input shaft 212, and the eccentric bearing 230 can also be made of metals such as ferrous metals. In this case, the decrease in permissible input speed can be suppressed.

[0196] Furthermore, since a large torsional stress is applied to the input shaft 212, it is desirable that the input shaft 212 be formed of a material with a stiffness higher than that of the first gear carrier 218. The input shaft 212 is formed of an ferrous metal with a torsional strength higher than that of aluminum. The ferrous metals used as constituent components in this embodiment can be carbon steel, bearing steel, stainless steel, etc., depending on the desired properties.

[0197] To ensure the connection strength between the first gear carrier 218 and the second gear carrier 220, it is desirable that the gear carrier pin 238 has high rigidity. For this purpose, the gear carrier pin 238 is formed of metal, and for weight reduction, the spacer 237 can also be formed of resin. In this embodiment, the gear carrier pin 238 is formed of an ferrous metal, and the spacer 237 is formed of POM. The housing 222 is integrated with the inner gear body 216a and can also be formed of the same material as the inner gear body 216a. For weight reduction, the first cover 221 and the second cover 223 can also be formed of resin. The first cover 221 and the second cover 223 can be formed of the same resin or different resins. In this embodiment, the first cover 221 and the second cover 223 can also be formed of, for example, POM.

[0198] Explain the operation of reducer 200.

[0199] If rotational power is transmitted from the drive device to the input shaft 212, the eccentric portion 212a of the input shaft 212 rotates about the rotation center line of the input shaft 212. As a result, the external gear 214 oscillates using the eccentric portion 212a. The external gear 214 oscillates by rotating its own shaft about the rotation center line of the input shaft 212. As the external gear 214 oscillates, the meshing position of the external gear 214 and the outer pin 217 of the internal gear 216 shifts sequentially. Consequently, for each revolution of the input shaft 212, the rotation of one of the gears, the external gear 214 and the internal gear 216, is equivalent to the difference between the number of teeth on the external gear 214 and the number of outer pins 217 on the internal gear 216. In this embodiment, the external gear 214 rotates, outputting decelerated rotation from the first gear carrier 218.

[0200] In this embodiment, the reducer 200, as the main bearings 224 and 226, does not have any metal components heavier than resin except for the metal rings 244 and 245, thus enabling further weight reduction.

[0201] The reducer 200 according to this embodiment can achieve the same effect as the various embodiments described above.

[0202] (Fourth implementation)

[0203] The fourth embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0204] Figure 6 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from the first embodiment lies in the points related to the main bearing. Other structures corresponding to those in the first embodiment are labeled with the same reference numerals as in the 300 section relative to the 100 section, and their descriptions are omitted.

[0205] In this embodiment, the reducer 300, such as Figure 6 As shown, the housing 322 is integrally formed with the inner peripheral sliding surface 348, which functions as the outer ring of the first main bearing 324 and the second main bearing 326. The entire housing 322 is formed of a thermally conductive material with higher wear resistance than the resin constituting the outer peripheral sliding surface 349, which functions as the inner ring of the first main bearing 324 and the second main bearing 326. Specifically, the housing 322 is made of metal.

[0206] Furthermore, in the following description, the first main bearing 324 and the second main bearing 326 may be referred to simply as main bearings 324 and 326.

[0207] In this embodiment, the reducer 300, such as Figure 6 As shown, the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 are formed such that their diameters increase as they move away from the external gear 314 in the direction along the central axis 3La. The inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 are formed such that their angles relative to the central axis 3La are in the range of, for example, 30° to 60°.

[0208] However, it is not limited to this case. The inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 may also be formed with an angle relative to the central axis 3La in the range of, for example, 40° to 50°, more preferably 45°.

[0209] Alternatively, in this embodiment, the angle between the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 of the reducer 300 and the central axis 3La can be set to 45° to 40°.

[0210] In this case, the angle between the end faces (outer peripheral surfaces) of the first gear carrier (shaft support) 318 and the end faces (outer peripheral surfaces) of the second gear carrier (retaining support) 320, both formed of resin, can be reduced to suppress their deformation. In other words, it is possible to prevent the axial thickness near the outer edge of the first gear carrier (shaft support) 318 and the outer edge of the second gear carrier (retaining support) 320 from becoming too thin.

[0211] In this embodiment, the reducer 300, housing 322, and first gear carrier (shaft support) 318 seal the internal space of the reducer 300 by means of first main bearing 324. Similarly, housing 322 and second gear carrier (retaining support) 320 seal the internal space of the reducer 300 by means of second main bearing 326. External gear 314 and external pin (internal gear pin) 317 are housed within the internal space of the reducer 300.

[0212] The main bearings 324 and 326 are sliding bearings. The internal space of the reducer 300 is sealed by the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349.

[0213] In the reducer 300 of this embodiment, the drive gear 313 that inputs driving force to the input shaft (eccentric body) 312 is configured to rotate integrally with the drive shaft 313a. Furthermore, in Figure 6 The diagram of the gear carrier pin is omitted in the text.

[0214] According to the reducer 300 of this embodiment, the housing 322 is entirely formed of a thermally conductive material, such as metal, which has higher wear resistance than resin. This allows heat generated at the main bearings 324 and 326 to be rapidly dissipated to the outside via the housing 322. Consequently, the temperature rise of the reducer 300 can be effectively suppressed.

[0215] Meanwhile, by making the components, except for the housing 322, inner pin 340, and drive gear 313, of resin, the weight of the reducer 300 can be achieved. Moreover, by making the housing 322 of metal, sufficient strength and rigidity can be maintained.

[0216] Furthermore, in the reducer 300 according to this embodiment, the angles of the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 relative to the central axis 3La are set within the aforementioned range. Therefore, without increasing the thickness of the reducer 300 in the axial direction, the areas of the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 can be increased. Moreover, deformation of the housing 322, the first gear carrier (shaft support) 318, and the second gear carrier (retaining support) 320 can be prevented, providing sufficient strength to prevent malfunctions. Thus, malfunctions are prevented, and operational stability can be maintained.

[0217] Furthermore, the reducer 300 according to this embodiment can achieve the same effect as the various embodiments described above.

[0218] (Fifth Embodiment)

[0219] The fifth embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0220] Figure 7 This is an enlarged cross-sectional view along the axial direction showing the vicinity of the main bearing in the reducer of this embodiment. In this embodiment, the difference from the fourth embodiment described above lies in the points related to the main bearing; other structures corresponding to those in the fourth embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0221] In this embodiment, the reducer 300, such as Figure 7As shown, the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 at the main bearings 324 and 326 bulge outwards from each other in the direction along the central axis 3La to form a protrusion. Alternatively, one of the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 may bulge outwards in the direction along the central axis 3La to form a protrusion.

[0222] Preferably, the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 are in contact with each other across their entire surfaces, thereby increasing the contact area of ​​the sliding support. However, there are cases where it is difficult to achieve the ideal state due to deformation or other reasons caused by manufacturing processes. Therefore, there is a possibility of malfunction due to wobbling or other reasons. Therefore, in order to prevent malfunction, a compression allowance is pre-formed on the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349.

[0223] As a compression allowance formed on the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349, such as Figure 7 As shown, the protrusion can be configured as a curved surface. According to this structure, the contact range between the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 can be set to a range predetermined by a compression allowance, reliably determining the contact range. This prevents non-contact states caused by manufacturing errors and ensures reliable contact between the inner circumferential sliding surface 348 and the outer circumferential sliding surface 349 near the center in the axial direction. Consequently, the operational stability of the first gear carrier (shaft support) 318 and the second gear carrier (holding support) 320 relative to the housing 322 can be improved.

[0224] Furthermore, it possesses sufficient strength to prevent deformation of the housing 322, the first gear carrier (shaft support) 318, and the second gear carrier (retaining support) 320 without causing malfunctions. Moreover, it can suppress temperature rise at the main bearings 324 and 326.

[0225] Furthermore, the reducer 300 according to this embodiment can achieve the same effect as the various embodiments described above.

[0226] (Sixth Embodiment)

[0227] The sixth embodiment of the speed reducer of the present invention will be described with reference to the accompanying drawings.

[0228] Figure 8 This is a cross-sectional view of the housing of the reducer according to this embodiment, showing the inner circumferential sliding surface of the main bearing. In this embodiment, the difference from the fourth embodiment described above lies in the points related to the main bearing; other structures corresponding to those in the fourth embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0229] In this embodiment, the reducer 300, such as Figure 8 As shown, a groove 360 ​​is formed on the inner circumferential sliding surface 348 of the housing 322.

[0230] The groove 360 ​​has a radial groove 361 extending radially along the inner circumferential sliding surface 348 and circumferential grooves 362 and 363 extending circumferentially.

[0231] Multiple radial grooves 361 are formed on the inner circumferential sliding surface 348 in a manner that they are separated from each other in the circumferential direction. The radial grooves 361 may also be separated, for example, by being spaced at equal intervals in the circumferential direction.

[0232] A peripheral groove 362 is formed in the axial direction near the center of the inner peripheral sliding surface 348. A peripheral groove 363 is formed in the axial direction near the external gear 314 on the inner peripheral sliding surface 348. A radial groove 361 is not formed in the axial direction at a position closer to the external gear 314 than the peripheral groove 363. The radial groove 361 extends in the axial direction away from the external gear 314 to the end of the inner peripheral sliding surface 348, thus maintaining continuity with the outside.

[0233] Circumferential grooves 362 and 363 are continuously formed around the entire circumference of the inner circumferential sliding surface 348. A radial groove 361 connects to the circumferential groove 363 such that it becomes the end of the circumferential groove 363. No other grooves are formed on the inner circumferential sliding surface 348 at positions closer to the input shaft 312 than the circumferential groove 363. That is, groove 360 ​​is separate from and does not contact the outer pin 317.

[0234] The depth and width of the groove 360 ​​can be exactly the same, and the peripheral grooves 362 and 363 can be larger than the radial groove 361.

[0235] according to Figure 8 The reducer 300 of this embodiment shown can capture foreign objects such as dust and particles that have entered between the inner peripheral sliding surface 348 and the outer peripheral sliding surface 349 using the groove 360. This prevents foreign objects from entering the internal space of the reducer 300. In other words, it prevents foreign objects such as dust and particles from affecting the operation of the external gear 314, the outer pin 317, etc. Furthermore, the groove 360 ​​can capture excess grease and lubricant between the inner peripheral sliding surface 348 and the outer peripheral sliding surface 349.

[0236] Furthermore, the reducer 300 according to this embodiment can achieve the same effect as the various embodiments described above.

[0237] Moreover, it can also Figure 8 The structure of this embodiment shown is similar to, for example... Figure 7 The structural combination shown in the fifth embodiment.

[0238] Figure 9This is an enlarged cross-sectional view of the housing 322 of the reducer 300 of this embodiment, showing the relationship between the compression allowance of the inner circumferential sliding surface 348 and the groove 360.

[0239] Figure 10 This is a cross-sectional view of the housing 322, which is another example of the relationship between the compression allowance of the inner circumferential sliding surface 348 and the groove 360 ​​of the reducer 300 in this embodiment.

[0240] Specifically, multiple arc-shaped protrusions are formed on the inner circumferential sliding surface 348 as compression allowances, and grooves are formed between these protrusions.

[0241] For example, such as Figure 9 As shown, two circumferentially parallel, arc-shaped protrusions are formed in the housing 322, with a circumferential groove 363 between them. A curved protrusion 348a is formed on the inner circumferential sliding surface 348, radially close to the input shaft 312. A curved protrusion 348b is also formed on the inner circumferential sliding surface 348, radially close to the outer periphery of the housing 322. Protrusions 348a and 348b are formed with approximately the same curvature at their cross-sections. A circumferential groove 363 is formed between protrusions 348a and 348b. This allows for a compression allowance to be provided on the inner circumferential sliding surface 348, improving operational stability and preventing contamination within the reducer 300.

[0242] Or, such as Figure 10 As shown, it is not a problem to make the curvature at the cross-section of the protrusion 348a greater than that at the cross-section of the protrusion 348b. Therefore, the peripheral groove 363 can be formed at a position that is closer to the input shaft 312 in the radial direction.

[0243] exist Figures 8-10 In the sixth embodiment shown, a groove 360 ​​is formed on the inner peripheral sliding surface 348 of the housing 322, but a groove can also be formed on, for example, the outer peripheral sliding surface 349. In this case, the outer peripheral sliding surface 349 is preferably formed of metal rather than resin. Therefore, the inner peripheral sliding surface 348 can be formed of resin. That is, as shown... Figure 3 In the second embodiment shown, metal rings can be provided on the gear carriers 318 and 320, and grooves can be formed on the outer peripheral sliding surface 349.

[0244] (Seventh Embodiment)

[0245] The seventh embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0246] Figure 11 This is a cross-sectional view along the axial direction of the reducer of this embodiment. Figure 12 yes Figure 11A sectional view at line XII-XII in the diagram. Figure 11 and Figure 12 In the attached diagram, reference 400 indicates a speed reducer.

[0247] The eccentric oscillating type reducer 400 of this embodiment is suitable for use as a reducer in rotating parts of various working machines, such as the rotating body of a robot, the wrist joint, and collaborative robots. This reducer 400 is used, for example, at speeds of 80 rpm to 200 rpm.

[0248] In this embodiment, the reducer 400, such as Figure 11 , Figure 12 As shown, the crankshaft (eccentric body) 410 is rotated by rotating the input shaft 408. Furthermore, it is configured such that the first external gear 414 and the second external gear 416 are oscillating and rotating in conjunction with the eccentric portions 410a and 410b of the crankshaft 410, thereby obtaining the output rotation obtained by decelerating the input rotation.

[0249] The reducer 400 includes: a housing (outer cylinder) 422, a gear carrier 404, an input shaft 408, a plurality of (e.g., 3) crankshafts 410, a first external gear 414, a second external gear 416, and a plurality of (e.g., 3) transmission gears 420.

[0250] The housing 422, which forms the outer surface of the reducer 400, has a generally cylindrical shape. A plurality of pin grooves 422b are formed on the inner circumferential surface of the housing 422. Each pin groove 422b is arranged to extend along the axial direction of the housing 422 and has a semi-circular cross-sectional shape in a section orthogonal to the axial direction. These pin grooves 422b are arranged at equal intervals in the circumferential direction on the inner circumferential surface of the housing 422.

[0251] The housing 422 has a plurality of internal toothed pins (external pins) 417. Each internal toothed pin 417 is respectively mounted in a pin groove 422b. Specifically, each internal toothed pin 417 is embedded in a corresponding pin groove 422b in an arrangement extending in the axial direction of the housing 422. Thus, the plurality of internal toothed pins 417 are arranged at equal intervals along the circumference of the housing 422. The first external tooth 414a of the first external gear 414 and the second external tooth 416a of the second external gear 416 mesh with these internal toothed pins 417. The plurality of internal toothed pins 417 constitute an internal gear 417A.

[0252] The gear carrier 404 is housed within the housing 422, positioned on the same axis as the housing 422. The gear carrier 404 rotates relative to the housing 422 about the same axis. Specifically, the gear carrier 404 is positioned radially inward of the housing 422. The gear carrier 404 is supported by a first main bearing 424 and a second main bearing 426, which are axially separated from each other, enabling it to rotate relative to the housing 422.

[0253] In the following description, the first main bearing 424 and the second main bearing 426 may be referred to simply as main bearings 424 and 426.

[0254] The gear carrier 404 includes: a second gear carrier (retaining bracket) 404b, and a base having a first gear carrier (shaft bracket) 404a and a plurality of (e.g., 3) shaft portions 404c.

[0255] The first gear carrier 404a is disposed within the housing 422 near one end in the axial direction. A through hole 404d is formed in the radial center of the first gear carrier 404a. Around the through hole 404d, a plurality of (e.g., 3) crankshaft mounting holes 404e (hereinafter simply referred to as mounting holes 404e) are provided at equal intervals in the circumferential direction.

[0256] The second gear carrier 404b is configured separately from the first gear carrier 404a in the axial direction, and is disposed within the housing 422 near its other end in the axial direction. A through hole 404f is provided at the radial center of the second gear carrier 404b. A plurality of (e.g., three) crankshaft mounting holes 404g (hereinafter simply referred to as mounting holes 404g) are formed around the through hole 404f. The mounting holes 404g are provided at positions corresponding to the plurality of mounting holes 404e of the first gear carrier 404a.

[0257] An internal space is formed within the housing 422 by the inner surface of the second gear carrier 404b and the inner surface of the first gear carrier 404a, as well as the inner circumferential surface of the housing 422.

[0258] Three shaft portions 404c are integrally formed with the first gear carrier 404a. The shaft portions 404c extend in a straight line from one main surface (inner surface) of the first gear carrier 404a toward the second gear carrier 404b. The three shaft portions 404c are arranged at equal intervals in the circumferential direction (see reference). Figure 12 ).

[0259] Each shaft 404c is fastened to the second gear carrier 404b using bolts 404h (see reference). Figure 11 Thus, the first gear carrier 404a, the shaft portion 404c, and the second gear carrier 404b are integrated.

[0260] The first gear carrier (shaft support) 404a and the second gear carrier (retaining support) 404b are rotatably supported on the housing 422 by means of the first main bearing 424 and the second main bearing 426. The first gear carrier 404a is rotatably supported on the housing 422 by means of the first main bearing 424. The second gear carrier 404b is rotatably supported on the housing 422 by means of the second main bearing 426.

[0261] The housing 422 is provided with: a first metal ring 444 located on the side of the first gear carrier 404a in the axial direction of the input shaft 408; and a second metal ring 445 located on the side of the second gear carrier 404b in the axial direction of the input shaft 408. The first metal ring 444 and the second metal ring 445 are fixed to the housing 422 as a whole.

[0262] The housing 422 has a recess for receiving the first metal ring 444. The first metal ring 444 is received in the recess of the housing 422 in the axial direction. The first metal ring 444 functions as the outer ring of the first main bearing 424. The outer periphery of the first metal ring 444 is connected to the inner periphery of the housing 422.

[0263] A first metal ring 444, functioning as the outer ring of the first main bearing 424, is located at the top end in the axial direction of the input shaft 408. The first metal ring 444 has an inner circumferential sliding surface 448 on its inner circumferential surface, which functions as the outer ring. The inner circumferential sliding surface 448 contacts the outer circumferential surface of the first gear carrier 404a. The first metal ring 444 is fixed to the housing 422 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0264] The housing 422 has a recess for receiving the second metal ring 445. The second metal ring 445 is received in the recess of the housing 422 in the axial direction. The second metal ring 445 functions as the outer ring of the second main bearing 426. The outer periphery of the second metal ring 445 is connected to the inner periphery of the housing 422.

[0265] A second metal ring 445, functioning as the outer ring of the second main bearing 426, is located at the base end side in the axial direction of the input shaft 408. The second metal ring 445 has an inner circumferential sliding surface 448 on its inner circumferential surface, which functions as the outer ring. The inner circumferential sliding surface 448 contacts the outer circumferential surface of the second gear carrier 404b. The second metal ring 445 is fixed to the housing 422 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0266] The first main bearing 424 is disposed between the first gear carrier 404a and the housing 422. The second main bearing 426 is disposed between the second gear carrier 404b and the housing 422. In this embodiment, the main bearings 424 and 426 are configured as sliding bearings.

[0267] The main bearings 424 and 426 have an inner peripheral sliding surface 448 that functions as an outer ring and an outer peripheral sliding surface 449 that functions as an inner ring. The outer peripheral sliding surface 449 is provided on the outer peripheral surface of the first gear carrier 404a and the second gear carrier 404b.

[0268] In the first metal ring 444 and the second metal ring 445, the inner circumferential sliding surface 448 and the outer circumferential sliding surface 449 are arranged radially at positions approximately equal to those of the inner toothed pin 417.

[0269] like Figure 11 , Figure 12 As shown, both the first metal ring 444 and the second metal ring 445 are configured to contact the internal toothed pin 417 in a direction along the central axis (main axis) 4La of the input shaft 408. By making the first metal ring 444, the second metal ring 445, and the internal toothed pin 417 contact each other in the axial direction, strength can be maintained along the entire length of the housing 422 in the axial direction.

[0270] The input shaft 408 functions as an input section for supplying driving force to a drive motor (not shown). The input shaft 408 is inserted into the through hole 404f of the second gear carrier 404b and the through hole 404d of the first gear carrier 404a. The input shaft 408 is configured with its central axis 4La aligned with the axes of the housing 422 and the gear carrier 404, and rotates about these axes. An input gear 408a is provided on the outer peripheral surface of the top end of the input shaft 408.

[0271] Three crankshafts 410 are arranged at equal intervals around the input shaft 408 within the housing 422 (see reference). Figure 12 Each crankshaft 410 is supported by a pair of crankshaft bearings 412a, 412b so that it can rotate about an axis relative to the gear carrier 404 (see reference). Figure 11 ).

[0272] Specifically, a first crankshaft bearing 412a is installed on a portion of each crankshaft 410 extending a predetermined length inward from one end along the axial direction. The first crankshaft bearing 412a is fixedly mounted in the mounting hole 404e of the first gear carrier 404a. A second crankshaft bearing 412b is installed on the other end of each crankshaft 410 along the axial direction. The second crankshaft bearing 412b is fixedly mounted in the mounting hole 404g of the second gear carrier 404b. Thus, the crankshaft 410 is rotatably supported by the first gear carrier 404a and the second gear carrier 404b.

[0273] Each crankshaft 410 has a shaft body 412c and eccentric portions 410a and 410b integrally formed with the shaft body 412c. The first eccentric portion 410a and the second eccentric portion 410b are arranged axially between portions supported by two crankshaft bearings 412a and 412b. The first eccentric portion 410a and the second eccentric portion 410b are each cylindrical in shape. The first eccentric portion 410a and the second eccentric portion 410b extend radially outward from the shaft body 412c in a state of eccentricity relative to the axis of the shaft body 412c. The first eccentric portion 410a and the second eccentric portion 410b are eccentric relative to the axis by a predetermined amount and are arranged with a predetermined angular phase difference between them.

[0274] At one end of the crankshaft 410, i.e., in the mounting hole 404e of the first gear carrier 404a, a fitting portion 410c for mounting the transmission gear 420 is provided.

[0275] The first external gear 414 is disposed in the closed space within the housing 422 and is mounted on the first eccentric portion 410a of each crankshaft 410 by means of the first roller bearing 418a. If the first eccentric portion 410a is eccentrically rotated by the rotation of each crankshaft 410, the first external gear 414 is linked to the eccentric rotation and oscillates and rotates while meshing with the internal gear pin 417.

[0276] The first external gear 414 is formed to a size slightly smaller than the inner diameter of the housing 422. The first external gear 414 has: a first external tooth 414a, a central through hole 414b, a plurality of (e.g., 3) first eccentric through holes 414c, and a plurality of (e.g., 3) shaft through holes 414d. The first external tooth 414a has a wave shape that is smoothly and continuously continuous throughout the entire circumference of the external gear 414.

[0277] A central through hole 414b is provided at the radial center of the first external gear 414. An input shaft 408 is inserted into the central through hole 414b with clearance.

[0278] Three first eccentric through holes 414c are provided at equal intervals around the central through hole 414b along the circumferential direction of the first external gear 414. The first eccentric part 410a of each crankshaft 410 is inserted into each first eccentric through hole 414c in a state where the first roller bearing 418a is clamped.

[0279] Three shaft through holes 414d are equally spaced around the central through hole 414b along the circumferential direction of the first external gear 414. Each shaft through hole 414d is positioned circumferentially between the three first eccentric through holes 414c. A corresponding shaft portion 404c is inserted into each shaft through hole 414d with clearance.

[0280] The second external gear 416 is disposed in a closed space within the housing 422 and is mounted on the second eccentric portion 410b of each crankshaft 410 by means of a second roller bearing 418b. The first external gear 414 and the second external gear 416 are arranged in the axial direction corresponding to the configuration of the first eccentric portion 410a and the second eccentric portion 410b. If the second eccentric portion 410b rotates eccentrically due to the rotation of each crankshaft 410, the second external gear 416 rotates in conjunction with this eccentric rotation, engaging with the internal gear pin 417 while oscillating.

[0281] The second external gear 416 is formed with a size slightly smaller than the inner diameter of the housing 422, and has the same structure as the first external gear 414. That is, the second external gear 416 has: a second external tooth 416a, a central through hole 416b, a plurality of (e.g., 3) second eccentric through holes 416c, and a plurality of (e.g., 3) shaft through holes 416d. They have the same structure as the first external tooth 414a, the central through hole 414b, the plurality of first eccentric through holes 414c, and the plurality of shaft through holes 414d. The second eccentric portion 410b of the crankshaft 410 is inserted into each of the second eccentric through holes 416c in a state in which the second roller bearing 418b is clamped.

[0282] Each transmission gear 420 transmits the rotation of the input gear 408a to the corresponding crankshaft 410. Each transmission gear 420 is fitted onto a mating portion 410c located at one end of the shaft body 412c of the corresponding crankshaft 410. Each transmission gear 420 rotates integrally with the crankshaft 410 about an axis that is the same as the rotation axis of the crankshaft 410. Each transmission gear 420 has external teeth 420a that mesh with the input gear 408a.

[0283] Among them, for the formation Figure 11 , Figure 12 The raw materials of each part of the reducer 400 shown in this embodiment will be described.

[0284] In this embodiment, the reducer 400, gear carrier 404, and housing 422 are made of resin, which makes the reducer 400 lightweight.

[0285] The inner circumferential sliding surface 448, which functions as the outer ring of the main bearings 424 and 426, is formed from a raw material with a higher thermal conductivity than the resin used to form the outer circumferential sliding surface 449, which functions as the inner ring.

[0286] In the main bearings 424 and 426, the raw materials for the metal rings 444 and 445, which function as outer rings, can be materials with higher thermal conductivity and higher strength than the resin of the gear carrier 404, which functions as an inner ring. These materials can also be metallic or non-metallic. In this embodiment, the metal rings 444 and 445 can also be formed from copper-based or aluminum-based metals or alloys, or from ferrous metals such as bearing steel or stainless steel.

[0287] Furthermore, the internal gear pin 417 can also be formed from the same material as the metal rings 444 and 445. The input shaft 408, crankshaft 410, first roller bearing 418a, second roller bearing 418b, first crankshaft bearing 412a, second crankshaft bearing 412b, transmission gear 420, etc., can also be formed from the same material as the metal rings 444 and 445. Moreover, the first external gear 414 and the second external gear 416 can also be formed from the same material as the gear carrier 404.

[0288] In this embodiment, the reducer 400, as the main bearings 424 and 426, does not have any metal components heavier than resin except for the metal rings 444 and 445, thus enabling further weight reduction.

[0289] In this embodiment, this configuration allows heat transferred from the main bearings 424 and 426, which are sliding bearings, to the first metal ring 444 and the second metal ring 445 to be dissipated to the outside. As a result, the heat dissipation performance of the reducer 400 is improved.

[0290] By improving heat dissipation on the inner and outer sliding surfaces 448 and 449, the resin is less likely to melt on the surface or stick together due to excessive temperature rise. This prevents malfunctions. Consequently, heat does not accumulate inside the reducer 400, preventing adverse conditions from occurring.

[0291] At the inner circumference of the housing 422, a first metal ring 444, an internal toothed pin 417, and a second metal ring 445, all made of metal, are arranged adjacent to and in contact with each other in the axial direction. Therefore, strength can be maintained along the entire length of the housing 422 in the axial direction. This prevents malfunction of the reducer 400 and maintains sufficient strength. Furthermore, it suppresses the increase of surface pressure on the tooth surfaces of the external gears 414 and 416, and prevents a shortened lifespan of the external gears 414 and 416.

[0292] Furthermore, this embodiment is not limited to the structure described above, and various modifications and improvements can be made without departing from its main idea. For example, in this embodiment, a structure with two oscillating external gears 414 and 416 is provided, but it is not limited to this. For example, it may also be a structure with one external gear, or a structure with three or more external gears.

[0293] Furthermore, in this embodiment, the input shaft 408 is disposed at the central portion of the gear carrier 404, and a plurality of crankshafts 410 are disposed around the input shaft 408, but it is not limited to this. For example, it can also be a central crankshaft type in which the crankshaft 410 is disposed at the central portion of the gear carrier 404. In this case, as long as the input shaft 408 is configured to mesh with the transmission gear 420 mounted to the crankshaft 410, the input shaft 408 can be disposed at any position.

[0294] Furthermore, in this embodiment, the housing 422 and gear carrier 404 are exemplified as being made of resin, and the metal rings 444 and 445 are made of metal such as aluminum alloy. However, for example, the housing 422 and the gear carrier 404 can be made of metal. In this case, they can be made of aluminum alloy, but it is not limited to this. In particular, as long as lightweight and the required rigidity can be maintained, the inner peripheral sliding surface 448 and the outer peripheral sliding surface 449 can be made of any different materials, such as resin and metal, and the raw materials of the components of the reducer 400 can be appropriately selected.

[0295] Furthermore, the reducer 400 according to this embodiment can achieve the same effect as the various embodiments described above.

[0296] (Eighth Embodiment)

[0297] The eighth embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0298] Figure 13 This is a cross-sectional view showing the reducer of this embodiment along the main axis direction. Figure 13 In the attached diagram, 500 indicates a speed reducer.

[0299] The reducer 500 in this embodiment is an eccentric oscillating type, such as... Figure 13 As shown, it has an input shaft (eccentric body) 512, an eccentric part 503, an external gear 514 corresponding to the eccentric part 503, an eccentric part bearing 509, a gear carrier 519, and an internal gear 516.

[0300] like Figure 13As shown, the input shaft 512 has an opening 512D at its output-side end along the axial direction of the central axis (main axis) 5La. The input shaft 512 also has a protrusion 512A at its input-side end in the axial direction, which can engage with a motor (not shown). The input shaft 512 is positioned radially at the center of the reducer 500. A support portion 512B is formed on the input shaft 512 near its output-side end, and a support portion 512C is formed near its input-side end.

[0301] The input shaft 512 is supported on the gear carrier 519 by a pair of bearings 534 and 536. Bearing 534 supports the input shaft 512 at support portion 512B. Bearing 536 supports the input shaft 512 at support portion 512C. The rolling elements of the pair of bearings 534 and 536 are balls. There is a clearance (not shown) between the rolling elements and the inner and outer rings.

[0302] An eccentric portion 503 is integrally formed with the input shaft 512 at a position where it is clamped by bearings 534 and 536. Thus, the input shaft 512 functions as an eccentric shaft.

[0303] The direction along the central axis 5La, from the eccentric portion 503 toward the bearing 534, is called the output side. The direction along the central axis 5La, from the eccentric portion 503 toward the bearing 536, is called the input side.

[0304] The eccentric portion 503 includes a first eccentric portion 503a, a second eccentric portion 503b, and a third eccentric portion 503c. The first eccentric portion 503a, the second eccentric portion 503b, and the third eccentric portion 503c are arranged in a configuration along the central axis 5La.

[0305] The first eccentric portion 503a and the third eccentric portion 503c (two outer eccentric portions) are arranged separately along the central axis 5La. A second eccentric portion (inner eccentric portion) 503b is arranged between the first eccentric portion 503a and the third eccentric portion 503c. That is, in the direction along the central axis 5La, the first eccentric portion 503a and the third eccentric portion 503c are arranged such that the second eccentric portion 503b is sandwiched in the middle.

[0306] The centers of the three eccentric parts 503a, 503b, and 503c are each eccentricated by the same amount relative to the central axis 5La of the input shaft 512. The eccentric phase configuration of these three eccentric parts 503a, 503b, and 503c is 120 degrees, obtained by dividing 360 degrees by the number of eccentric parts 503a, 503b, and 503c, which is 3. The position of maximum eccentricity of each eccentric part 503a, 503b, and 503c relative to the central axis 5La is different in its circumferential position relative to the central axis 5La.

[0307] Specifically, in the case of a right-hand (or left-hand) rotation relative to the central axis 5La of the input shaft 512, the maximum eccentricity position of the second eccentricity portion 503b is offset by 120 degrees, based on the maximum eccentricity position of the first eccentricity portion 503a. Furthermore, the maximum eccentricity position of the third eccentricity portion 503c is set to be 120 degrees offset from the maximum eccentricity position of the second eccentricity portion 503b. Moreover, the maximum eccentricity position of the first eccentricity portion 503a becomes 120 degrees offset from the maximum eccentricity position of the third eccentricity portion 503c.

[0308] An eccentric bearing 509 is disposed on the outer periphery of the eccentric portion 503 and is configured to transmit the eccentric rotation of the eccentric portion 503. Corresponding to each eccentric portion 503a, 503b, and 503c, there are first eccentric bearings 509a, 509b, and 509c. Each of these three eccentric bearings 509a, 509b, and 509c has rollers and a cage that restricts the circumferential position of the rollers. None of these three eccentric bearings 509a, 509b, and 509c has an inner ring and an outer ring. Furthermore, the term "roller" includes the concept of "needle roller."

[0309] The external gear 514 is mounted and fixed to the outer periphery of the eccentric portion 503 by means of the eccentric bearing 509. The external gear 514 oscillates and rotates by means of the eccentric portion 503. The external gear 514 has a first external gear 514a, a second external gear 514b, and a third external gear 514c corresponding to each of the eccentric portions 503a, 503b, and 503c.

[0310] Each of the three external gears 514a, 514b, and 514c has multiple inner pin holes 515a, 515b, and 515c. These inner pin holes 515a, 515b, and 515c pass through each of the external gears 514a, 514b, and 514c. An inner pin 540 with a rotatable inner roller 537 engages with each of the external gears 514a, 514b, and 514c with some clearance.

[0311] The gear carrier 519 includes a first gear carrier (shaft support) 518 and a second gear carrier (retaining support) 520. The first gear carrier 518 is integrally formed with the inner pin 540.

[0312] The first gear carrier 518 and the second gear carrier 520 are integrated by means of bolt 540a. Bolt 540a is screwed in from the outside of the second gear carrier 520 and connected to the inner pin 540.

[0313] The first gear carrier 518 is positioned closer to the output side than the first external gear 514a. The second gear carrier 520 is positioned closer to the input side than the third external gear 514c.

[0314] Gear carrier 519 is supported on housing 522 by first main bearing 524 and second main bearing 526. Gear carrier 518 is supported on housing 522 by first main bearing 524. Gear carrier 520 is supported on housing 522 by second main bearing 526.

[0315] In the following description, the first main bearing 524 and the second main bearing 526 may be referred to simply as main bearings 524 and 526.

[0316] Both main bearings 524 and 526 are sliding bearings with an inner circumferential sliding surface 548 and an outer circumferential sliding surface 549. Main bearings 524 and 526 each have a first metal ring 544 and a second metal ring 545.

[0317] In the following description, the first metal ring 544 and the second metal ring 545 may be referred to simply as metal rings 544 and 545.

[0318] The main bearing 524 has a first metal ring 544. The second main bearing 526 has a second metal ring 545. The first metal ring 544 is disposed on the output side of the housing 522. The second metal ring 545 is disposed on the input side of the housing 522. The first metal ring 544 and the second metal ring 545 are fixedly integrated with the housing 522.

[0319] The outer periphery of the first metal ring 544 is fixed to the inner periphery of the housing 522. A recess for receiving the first metal ring 544 is provided on the inner periphery of the housing 522. The first metal ring 544 is received in the recess of the housing 522 along the axial direction. The first metal ring 544 functions as the outer ring of the first main bearing 524.

[0320] A first metal ring 544, functioning as the outer ring of the first main bearing 524, is located on the output side of the housing 522. The first metal ring 544 has an inner circumferential sliding surface 548 that functions as the outer ring. The inner circumferential sliding surface 548 contacts the first gear carrier (shaft support) 518. The first metal ring 544 is fixed to the housing 522 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0321] The outer periphery of the second metal ring 545 is fixed to the inner periphery of the housing 522. A recess for receiving the second metal ring 545 is provided on the inner periphery of the housing 522. The second metal ring 545 protrudes toward the input side relative to the recess of the housing 522 in the direction along the central axis 5La. The second metal ring 545 functions as the outer ring of the second main bearing 526.

[0322] A second metal ring 545, functioning as the outer ring of the second main bearing 526, is located on the input side of the housing 522. The second metal ring 545 is exposed on the input side of the housing 522. The second metal ring 545 has an inner circumferential sliding surface 548 that functions as the outer ring. The inner circumferential sliding surface 548 contacts the second gear carrier (retaining bracket) 520. The second metal ring 545 is fixed to the housing 522 using a clearance fit, interference fit, or transition fit. The clearance can also be set corresponding to the difference in thermal expansion rates.

[0323] The first main bearing 524 is disposed between the first gear carrier 518 and the housing 522. The second main bearing 526 is disposed between the second gear carrier 520 and the housing 522. The main bearings 524 and 526 have an outer peripheral sliding surface 549 that functions as an inner ring. The outer peripheral sliding surface 549 contacts the inner peripheral sliding surface 548.

[0324] The outer peripheral sliding surface 549 is provided on the outer peripheral surface of the gear carriers 518 and 520. The outer peripheral sliding surface 549 moves in a manner that maintains a state of sliding relative to the inner peripheral sliding surface 548 formed on the inner peripheral surface of the metal rings 544 and 545.

[0325] The outer peripheral sliding surfaces 549 of the main bearings 524 and 526, which function as inner rings, are formed on the gear carriers 518 and 520, and the inner peripheral sliding surfaces 548, which function as outer rings, are formed on the metal rings 544 and 545. The metal rings 544 and 545 are supported on the inner periphery of the housing 522.

[0326] The inner circumferential sliding surface 548 and the outer circumferential sliding surface 549 formed by the first metal ring 544 and the second metal ring 545 are arranged radially at positions approximately equal to those of the outer pin (internal toothed pin) 517.

[0327] The first metal ring 544 and the second metal ring 545 are configured to contact the internal toothed pin 517 in a direction along the central axis 5La of the input shaft 512. The first metal ring 544, the second metal ring 545 and the internal toothed pin 517 are in contact with each other in a direction along the central axis 5La, thereby maintaining strength of the housing 522 along the entire length of the housing 522 in the direction along the central axis 5La.

[0328] The inner circumferential sliding surface 548, which functions as the outer ring of the main bearings 524 and 526, is formed from a raw material with a higher thermal conductivity than the resin of the gear carriers 518 and 520, which forms the outer circumferential sliding surface 549, which functions as the inner ring.

[0329] In the main bearings 524 and 526, the raw materials for forming the metal rings 544 and 545, which function as outer rings, can be materials with higher thermal conductivity and higher strength than the resin of the gear carriers 518 and 520, which function as inner rings. These materials can also be metallic or non-metallic. In this embodiment, the metal rings 544 and 545 can also be formed from copper-based or aluminum-based metals, or ferrous metals such as bearing steel.

[0330] The internal gear 516 has: a cylindrical internal toothed pin 517; and an internal gear body 516a, which has a pin groove 516b that supports the internal toothed pin 517 so that it can rotate.

[0331] The internal gear body 516a and the housing 522 are integrally formed. There is a small difference in the number of teeth between the internal gear 516 and the first external gear 514a. There is a small difference in the number of teeth between the internal gear 516 and the second external gear 514b. There is a small difference in the number of teeth between the internal gear 516 and the third external gear 514c.

[0332] In addition, an oil seal 533 is disposed between the housing 522 and the first gear carrier 518, on the outer side of the metal ring 544.

[0333] If the input shaft 512 is driven to rotate by a motor (not shown), the eccentric portion 503 disposed on the outer periphery of the input shaft 512 rotates eccentrically along with the input shaft 512. Due to the rotation of the eccentric portion 503, the external gears 514a, 514b, and 514c corresponding to each of the eccentric portions 503a, 503b, and 503c will also oscillate and rotate around the input shaft 512. However, the rotation of each external gear 514a, 514b, and 514c is constrained by the internal gear 516, so they only oscillate while in contact with the internal gear 516.

[0334] The oscillating component is absorbed by the inner pin holes 515a, 515b, 515c and the inner pin 540 (and the inner roller 537). As a result, the first external gear 514a, the second external gear 514b, and the third external gear 514c rotate relative to the fixed internal gear 516 by an amount equivalent to the difference in the number of teeth between them and the internal gear 516. That is, only the rotational component generated by the difference in the number of teeth between the first external gear 514a, the second external gear 514b, the third external gear 514c and the internal gear 516 is transmitted to the gear carrier 519.

[0335] To form Figure 13 The raw materials of each part of the reducer 500 shown in this embodiment will be described.

[0336] In this embodiment, the reducer 500, gear carrier 519, housing 522, first external gear 514a, second external gear 514b, and third external gear 514c are formed of resin, thereby making the reducer 500 lightweight.

[0337] The inner circumferential sliding surface 548, which functions as the outer ring of the main bearings 524 and 526, can also be formed from a raw material with a higher thermal conductivity than the resin used to form the outer circumferential sliding surface 549, which functions as the inner ring.

[0338] The raw materials used to form the metal rings 544 and 545, which function as the outer rings, can be materials with higher thermal conductivity and higher strength than the resin of the gear carrier 519, which functions as the inner ring. They can also be metallic or non-metallic materials. In this embodiment, the metal rings 544 and 545 can also be formed from copper-based or aluminum-based metals, alloys, or ferrous metals such as bearing steel or stainless steel.

[0339] Furthermore, the internal toothed pin 517 can also be formed from the same raw material as the metal rings 544 and 545. The input shaft 512, eccentric bearing 509, bearings 534 and 536, etc., can also be formed from the same raw material as the metal rings 544 and 545.

[0340] In the reducer 500 of this embodiment, the main bearings 524 and 526 do not have any metal components heavier than resin except for the metal rings 544 and 545, thus enabling further weight reduction.

[0341] In this embodiment, the heat transferred from the main bearings 524 and 526, which are sliding bearings, to the first metal ring 544 and the second metal ring 545 can be dissipated to the outside, thus improving heat dissipation.

[0342] For the inner circumferential sliding surface 548 and the outer circumferential sliding surface 549, the improved heat dissipation prevents the resin from melting on the surface or sticking together due to excessive temperature rise. Therefore, it prevents malfunctions. Consequently, heat does not accumulate inside the reducer 500, preventing adverse conditions from occurring.

[0343] At the inner circumference of the housing 522, a first metal ring 544, an internal toothed pin 517, and a second metal ring 545, all made of metal, are adjacent to and in contact with each other in the axial direction. This ensures that strength is maintained along the entire axial length of the housing 522. Consequently, malfunction of the reducer 500 is prevented, and sufficient strength is maintained.

[0344] In addition, Figure 13 In the embodiment shown, the first gear carrier 518 functions as an output shaft relative to a machine not shown. The gear carrier 519 includes a second gear carrier 520, which is configured to support the inner pin 540 at both ends, or it may be configured to cantilever support the inner pin.

[0345] Furthermore, while there are three or more eccentric bodies arranged in an eccentric phase of 360 degrees / (number of eccentric bodies), this is not a limitation. Moreover, it is not limited to a structure in which the axial length of the inner eccentric body located inside the outer eccentric body is longer than the axial length of the two outer eccentric bodies located at opposite ends of the axial direction.

[0346] The reducer 500 according to this embodiment can achieve the same effect as the various embodiments described above.

[0347] (9th embodiment)

[0348] The ninth embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0349] Figure 14 This is a cross-sectional view along the main axis direction of the reducer in this embodiment. Figure 15 yes Figure 14 The XV-XV section view in the diagram. Figure 14 and Figure 15 In the attached diagram, reference 600 indicates a speed reducer.

[0350] The reducer 600 of this embodiment is an eccentric oscillating type reducer in which the external gear meshing with the internal gear oscillates, thereby causing one of the gears, the internal gear and the external gear, to rotate, and the rotation component is output from the output member to the driven device.

[0351] like Figure 14 , Figure 15As shown, the reducer 600 of this embodiment includes: an input shaft 612, an external gear 614, an internal gear 616, a first gear carrier 618, a second gear carrier 620, a housing 622, a first main bearing 624, a second main bearing 626, and a gear carrier pin 638.

[0352] Hereinafter, the direction along the central axis (main axis) 6La of the internal gear 616 will be referred to as the "axial direction," and the circumferential direction and radial direction of the circle centered on this central axis 6La will be designated as "circumferential" and "radial," respectively. For convenience, one side of the axial direction ( Figure 14 The right side of the input is called the input side, and the other side ( Figure 14 The left side of the input is called the inverse input side or the output side.

[0353] In the following description, the first gear carrier 618 and the second gear carrier 620 may be referred to simply as gear carriers 618 and 620. The first main bearing 624 and the second main bearing 626 may also be referred to simply as main bearings 624 and 626.

[0354] The input shaft 612 rotates around the rotation center line using rotational power input from the drive source. Figure 14 , Figure 15 The reducer 600 shown in this embodiment is a type of central crankshaft where the rotation center line of the input shaft 612 is set on the same axis as the central axis 6La of the internal gear 616. The drive source is, for example, a motor, a geared motor, an engine, etc.

[0355] The input shaft 612 is an eccentric shaft having multiple eccentric portions 612a for oscillating the external gear 614. Therefore, the input shaft (eccentric body) 612 is sometimes referred to as a crankshaft. The core of the eccentric portion 612a is eccentric relative to the rotation center line of the input shaft 612. In this embodiment, two eccentric portions 612a are arranged adjacent to each other on the input shaft 612. The eccentric phases of adjacent eccentric portions 612a are offset by 180°.

[0356] The input side of the input shaft 612 is supported on the second gear carrier 620 by means of an input shaft bearing 634, and the reverse input side is supported on the first gear carrier 618 by means of an input shaft bearing 634. The input shaft 612 is supported so as to be rotatable relative to the first gear carrier 618 and the second gear carrier 620. There are no particular limitations on the structure of the input shaft bearing 634, but in this example it is a ball bearing with spherical rolling elements.

[0357] The internal gear 616 meshes with the external gear 614. The internal gear 616 of this embodiment has: an internal gear body 616a, which is integrated with the housing 622; and an external pin (internal tooth pin) 617, which is disposed in each pin groove 616b, and the pin grooves 616b are formed in the internal gear body 616a in a circumferentially spaced manner.

[0358] The outer pin 617 is a cylindrical or cylindrical pin member that is rotatably supported on the internal gear body 616a. The outer pin 617 has a uniform diameter along its entire axial length. The outer pin 617 constitutes the internal teeth of the internal gear 616. The number of outer pins 617 (the number of internal teeth) of the internal gear 616 is slightly more than the number of external teeth of the external gear 614 (only one more in this example).

[0359] The internal gear body 616a and housing 622 are formed of resin. Various resins can be used for the internal gear body 616a and housing 622; in this example, they are formed of, for example, POM (polyacetal). However, this is not a limitation; for example, the internal gear body 616a and housing 622 can also be formed of resins different from POM, such as PEEK (polyetheretherketone).

[0360] The resin used in the internal gear body 616a, the housing 622, and other constituent components of this embodiment can be a resin containing reinforcing fibers such as glass fiber and carbon fiber, or a resin without reinforcing fibers, or a material formed by impregnating a substrate such as paper or cloth with resin and then laminating it. The resin used in each constituent component of this embodiment can also be a resin mixed with thermally conductive fillers.

[0361] In the reducer 600, the outer pin 617 can also be formed from a raw material with a higher thermal conductivity [W / (m·K)] than the resin of the internal gear body 616a.

[0362] The raw materials used to form export version 617 can be materials with higher thermal conductivity and stiffness than the resin of the internal gear body 616a. These materials can also be metals, resins with high thermal conductivity, or non-metallic materials. Export version 617 can also be a resin mixed with, for example, carbon nanotubes (CNTs) or boron nitride nanotubes (BNNTs). Figure 14 , Figure 15 The outer pin 617 of this embodiment shown is formed of ferrous metals such as bearing steel.

[0363] Export 617 can be either a solid or hollow component. Export 617 can also be a multi-layered component consisting of a core material encased in a surface material. For example, export 617 may have one of the core material and the surface material being an ferrous metal, and the other a copper-based or aluminum-based metal. In this case, a balance between mechanical and thermal properties can be achieved. Furthermore, as another example, export 617 may have one of the core material and the surface material being made of metal, and the other of resin. Additionally, export 617 may also be made of sintered metal, ceramic, or the like.

[0364] The external gear 614 is individually provided with corresponding eccentric portions 612a. The external gear 614 is supported on the eccentric portions 612a in a rotatable manner by means of eccentric bearings 630.

[0365] like Figure 15 As shown, on the external gear 614, at a position offset relative to the axis of the external gear 614, a plurality of gear carrier pin holes (inner pin holes) 639 are formed at equal intervals in the circumferential direction. Gear carrier pins (inner pins) 638 are inserted into the gear carrier pin holes 639. These gear carrier pin holes 639 are all of the same diameter. The diameter of the gear carrier pin holes 639 is set to be larger than the diameter of the gear carrier pins 638.

[0366] The external gear 614, like the internal gear body 616a, is formed of resin. Various resins can be used for the external gear 614. The external gear 614 is positioned closer to the input shaft 612 than the internal gear body 616a. The external gear 614 can also be formed of, for example, PEEK. However, it is not limited to this; the external gear 614 can also be formed of a resin different from PEEK, such as POM.

[0367] Multiple gear carrier pin holes 639 are formed in the same position in the radial direction and are circular. Wavy teeth are formed on the outer periphery of the external gear 614. The wavy teeth move while contacting the internal gear 616, causing the external gear 614 to oscillate in a plane with the central axis 6La as the normal. A clearance is provided between the gear carrier pin 638 and the gear carrier pin hole 639 to absorb the oscillation component of the external gear 614. The gear carrier pin 638 is in partial contact with the inner wall surface of the gear carrier pin hole 639.

[0368] Gear carriers 618 and 620 are positioned on opposite sides of the external gear 614 along its axial direction. The first gear carrier (shaft support) 618 is positioned on the side of the external gear 614 on the reverse input side. The second gear carrier (retaining support) 620 is positioned on the side of the external gear 614 on the input side.

[0369] The first gear carrier 618 and the second gear carrier 620 are rotatably supported on the housing 622 by means of the first main bearing 624 and the second main bearing 626. The first gear carrier (shaft support) 618 is rotatably supported on the housing 622 by means of the first main bearing 624. The second gear carrier (retaining support) 620 is rotatably supported on the housing 622 by means of the second main bearing 626.

[0370] The gear carriers 618 and 620 are generally formed in a disk shape. The first gear carrier 618 supports the input shaft 612 for free rotation via the input shaft bearing 634. The second gear carrier 620 supports the input shaft 612 for free rotation via the input shaft bearing 634.

[0371] The gear carrier pin (inner pin) 638 is connected to the first gear carrier (shaft support) 618 and the second gear carrier (retaining support) 620 by bolts 638a. Bolts 638a are made of rigid raw materials such as ferrous metals.

[0372] The first gear carrier 618 and the second gear carrier 620 are connected by a plurality of gear carrier pins 638. The gear carrier pins 638 axially pass through the plurality of external gears 614 at a position radially offset relative to the shaft core of the external gear 614. In this embodiment, the gear carrier pins 638 are provided independently of the gear carriers 618 and 620. However, this is not a limitation; a portion of the gear carrier pins 638 may also be integrally formed with the gear carriers 618 and 620.

[0373] Either the first gear carrier 618 or the housing 622 functions as an output member that supplies rotational power to the driven device, while the other component functions as a fixed member attached to an external member that supports the reducer 600. The output member is rotatably supported on the fixed member by means of main bearings 624 and 626. The driven member, which is rotated by the reducer 600, can also be connected to the end face of the first gear carrier 618 on the opposite input side using bolts or the like. Alternatively, the driven member, which is rotated by the reducer 600, can also be connected to the outer peripheral flange of the housing 622 using bolts or the like.

[0374] The housing 622 is generally formed as a hollow cylinder. An internal gear 616 is provided on the inner periphery of the housing 622. A flange or the like may also be provided on the outer periphery of the housing 622. A pin groove 616b supporting an outer pin 617 is formed in the housing 622 along the central axis 6La. The outer pin 617 extends outward relative to the pin groove 616b in the direction of the central axis 6La.

[0375] In other words, the length of the outer pin 617 in the direction of the central axis 6La is set to be greater than the length of the outer pin 616b in the direction of the central axis 6La. The outer pin 617 protrudes outward from the outer pin 616b in the direction of the central axis 6La.

[0376] The gear carriers 618 and 620 are provided with circumferential recesses 646 and 647 that accommodate the portion of the outer pin 617 exposed from the pin groove 616b. The circumferential recesses 646 and 647 are continuously formed along the entire circumference of the gear carriers 618 and 620. The circumferential recesses 646 and 647 have the same cross-sectional shape along their entire circumferential length.

[0377] The radial cross-sections of the circumferential recesses 646 and 647 are rectangular. The radial cross-sectional shape of the circumferential recesses 646 and 647 corresponds to the axial cross-section of the outer pin 617.

[0378] The recesses 646 and 647 each have an annular surface 649a formed flat along the radial direction and a cylindrical outer peripheral surface 649b continuously disposed with the annular surface 649a.

[0379] As the gear carriers 618 and 620 and the housing 622 rotate relative to each other about the central axis 6La, the portion of the outer pin 617 exposed from the pin groove 616b can move circumferentially inside the circumferential recesses 646 and 647.

[0380] The circumferential recesses 646 and 647 of the gear carriers 618 and 620 function as the inner rings of the main bearings 624 and 626.

[0381] The main bearings 624 and 626 have an outer pin 617 and a pin groove 616b that serves as a retainer to limit the circumferential position of the outer pin 617. The internal gear body 616a of the main bearings 624 and 626 functions as an outer ring. In other words, the main bearings 624 and 626 in this embodiment are configured as rolling bearings consisting of an outer pin 617.

[0382] The first main bearing 624 is disposed between the first gear carrier 618 and the housing 622. The second main bearing 626 is disposed between the second gear carrier 620 and the housing 622.

[0383] The first main bearing 624 includes a pin groove 616b in the housing 622, an outer pin 617, and a circumferential recess 646 disposed on the outer periphery of the input side of the first gear carrier 618.

[0384] In the peripheral recess 646, the end face 617b of the outer pin 617 is slightly separated from or in contact with the annular surface 649a. In the peripheral recess 646, the peripheral surface 617c of the outer pin 617 is in contact with the outer peripheral surface 649b.

[0385] The output-side end face 617b of the outer pin 617 moves in a non-contact manner relative to the annular surface 649a, or slides in contact with and moves relative to the annular surface 649a, as the first gear carrier 618 and the housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c near the end face 617b of the outer pin 617 rolls in contact with and moves relative to the outer circumferential surface 649b, as the first gear carrier 618 and the housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c of the outer pin 617 maintains a linear contact with the outer circumferential surface 649b in the direction of the central axis 6La.

[0386] The second main bearing 626 includes a pin groove 616b in the housing 622, an outer pin 617, and a circumferential recess 647 disposed on the outer periphery of the output side of the second gear carrier 620.

[0387] In the peripheral recess 647, the end face 617b of the outer pin 617 is slightly separated from or in contact with the annular surface 649a. In the peripheral recess 647, the peripheral surface 617c of the outer pin 617 is in contact with the outer peripheral surface 649b.

[0388] The input-side end face 617b of the outer pin 617 moves in a non-contact manner relative to the annular surface 649a, or slides in contact with and moves relative to the annular surface 649a, as the second gear carrier 620 and housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c near the end face 617b of the outer pin 617 rolls in contact with and moves relative to the outer circumferential surface 649b, as the second gear carrier 620 and housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c of the outer pin 617 maintains a linear contact with the outer circumferential surface 649b in the direction of the central axis 6La.

[0389] The contact length along the central axis 6La between the peripheral surface 617c and the outer peripheral surface 649b is equal at all of the multiple outer pins 617. The contact positions between the peripheral surface 617c and the outer peripheral surface 649b are all circumferentially separated by equal distances at all of the multiple outer pins 617. The circumferential separation distance of the multiple outer pins 617 is maintained by the circumferential separation distance of the pin groove 616b.

[0390] In the main bearings 624 and 626, radially outward forces are applied from the circumferential recesses 646 and 647 to both ends of the outer pin 617 in the direction along the central axis 6La. Furthermore, radially inward forces are applied from the pin groove 616b to the central portion of the outer pin 617 in the direction along the central axis 6La. Thus, the main bearings 624 and 626 support the housing 622 and the gear carriers 618 and 620 circumferentially, enabling relative rotation.

[0391] The distance between the annular surface 649a of the circumferential recess 646 and the annular surface 649a of the circumferential recess 647 along the central axis 6La is set to be slightly larger than the axial dimension of the outer pin 617, or set to be approximately equal to the axial dimension of the outer pin 617.

[0392] Furthermore, the diameter of the outer peripheral surface 649b from the central axis 6La is set to the value obtained by subtracting the diameter of the outer pin 617 from the maximum diameter in the pin groove 616b.

[0393] The radial dimension of the annular surface 649a can be set to be equal to the diameter of the outer pin 617. In this case, the outer peripheral surfaces of the gear carriers 618 and 620 have a diameter equal to the diameter of the cylindrical surface connected to the outermost radial position of the outer pin 617. At the same time, the entire end face 617b of the outer pin 617 can contact the annular surface 649a.

[0394] Alternatively, the radial dimension of the annular surface 649a can be set to be smaller than the diameter of the outer pin 617. In this case, the cylindrical surface at the outermost radial position connected to the outer pin 617 has a diameter larger than the diameter of the outer circumferential surface of the gear carrier 618, 620.

[0395] Furthermore, the axial length of the outer peripheral surface 649b is set to be approximately equal to the axial length of the portion of the peripheral surface 617c of the outer pin 617 that contacts the outer peripheral surface 649b.

[0396] In the main bearings 624 and 626, the outer pin 617 is formed of a thermally conductive material with higher wear resistance than the resin of the housing 622 and the gear carriers 118 and 120. The housing 622 forms a pin groove 616b (inner circumferential surface 648) that functions as an outer ring, and the gear carriers 118 and 120 form an outer circumferential surface 649b that functions as an inner ring.

[0397] Specifically, the raw materials used to form export 617 can be materials with higher thermal conductivity and higher strength than the resins of the housing 622 and gear carriers 618 and 120. They can also be metallic or non-metallic materials. Figure 14 , Figure 15 The outer sleeve 617 shown in this embodiment can also be formed of copper-based or aluminum-based metals, alloys, or ferrous metals such as bearing steel.

[0398] In the main bearings 624 and 626, the outer pin 617 is sandwiched between the pin groove 616b, which functions as the inner circumferential surface 648 and the outer circumferential surface 649b, which functions as the inner ring.

[0399] In other words, export version 617 is sandwiched between housing 622 and gear carriers 618 and 620.

[0400] The portion of the outer pin 617 that protrudes relative to the pin groove 616b in the direction along the central axis 6La is also served by the outer pin constituting the internal gear 616. Therefore, the main bearing 624, the internal gear 616, and the main bearing 626 are arranged adjacent to each other along the central axis 6La. This allows strength to be maintained along the entire axial length of the reducer 600.

[0401] The gear carrier pin (inner pin) 638 is inserted into the gear carrier pin hole (inner pin hole) 639 formed in the external gear 614 with a gap. One end of the gear carrier pin 638 is embedded in the recess 618c of the first gear carrier 618, and the other end is embedded in the recess 620c of the second gear carrier 620. The gear carrier pin 638 is fixed to the recesses 618c and 620c by bolts 638a. The gear carrier pin 638 can also be pressed into the recesses 618c and 620c, in which case it is not fixed by bolts or the like.

[0402] The gear carrier pin (inner pin) 638 contacts a portion of the gear carrier pin hole 639 formed in the external gear 614. Thus, the gear carrier pin 638 constrains the rotation of the external gear 614, allowing only oscillation. The gear carrier pin 638 functions as a connecting member facilitating the transmission of power between the first gear carrier 618 and the second gear carrier 620 and the external gear 614.

[0403] Furthermore, it is acceptable to designate a portion of the multiple gear carrier pins 638 as gear carrier pins that do not contact the gear carrier pin hole 639 of the external gear 614. In this case, the gear carrier pins 638 do not contribute to the constraint of the rotation of the external gear 614. Therefore, in this case, the gear carrier pins 638 function as connecting members that only contribute to the connection between the first gear carrier 618 and the second gear carrier 620.

[0404] As a speed reducer, its applications have expanded to include collaborative robots that operate near humans. To broaden its applications, lightweight and low-noise reduction of the speed reducer is desired. Conventional speed reducers are constructed from ferrous metal components; to achieve weight reduction, it is desirable to form the components from low-density raw materials. Resin and the like are preferred materials for this purpose.

[0405] On the other hand, if the constituent components are made of resin, it is believed that adverse conditions such as failure will occur due to a decrease in strength and stiffness. Furthermore, if the constituent components are made of resin, it is believed that the temperature will rise due to reduced heat dissipation, thereby shortening the lifespan. Therefore, it is desirable to select the raw materials used to form each constituent component while considering strength maintenance, lightweighting, and heat dissipation. In particular, it is necessary to avoid a decrease in strength resulting from lightweighting.

[0406] In the reducer 600, many of its components can be made of resin to reduce weight. The housing 622, gear carriers 618 and 620, and external gear 614 occupy most of the volume of the reducer 600's components. Therefore, by making these components of resin, a significant reduction in weight can be achieved.

[0407] Furthermore, preferably, considering strength and heat dissipation, the input shaft 612, gear carrier pin (inner pin) 638 and bolt 638a, eccentric bearing 630, input shaft bearing 634, and outer pin 617 are made of metal.

[0408] Furthermore, in the reducer 600, the main bearings 624 and 626 are not provided with bearings of different structures, so that the outer pin 617 can be used to support the housing 622 and the gear carriers 618 and 620 for rotation. Therefore, further weight reduction of the reducer 600 is possible. Moreover, since the main bearings 624 and 626 do not have metal components other than the outer pin 617, further weight reduction is possible.

[0409] In the main bearings 624 and 626, the circumferential surface 617c of the outer pin 617 rolls into contact with the outer circumferential surface 649b and moves relative to the outer circumferential surface 649b as the gear carriers 618 and 620 and the housing 622 rotate relative to the central axis 6La. Therefore, compared with the sliding contact structure, friction can be reduced and the operational stability can be improved.

[0410] Furthermore, the annular surface 649a and the outer peripheral surface 649b are formed of resin, and the outer pin 617 is formed of metal. Therefore, heat dissipation is improved by efficiently dissipating heat generated from the parts where they come into contact with each other.

[0411] In the reducer 600, heat generation is often significant within its interior, particularly around the main bearings 624 and 626. Furthermore, heat generation is often significant around the input shaft 612, which rotates at a relatively high speed. Moreover, if the gear carrier pin (inner pin) 638 and the external gear 614 are not maintained with sufficient strength, there is a possibility that the reducer 600 may malfunction.

[0412] Thus, with limited heat dissipation from the internal components to the external environment, the temperature of the reducer rises. If the temperature increases, the stiffness and strength of the resin components decrease drastically; therefore, if this condition is maintained and continued in use, the likelihood of breakage is high.

[0413] Therefore, for components that move relative to each other, when one component is made of resin, it is desirable that the other component is made of a raw material with higher wear resistance and thermal conductivity [W / (m·K)] than the resin component. In this case, compared to the case of lower thermal conductivity, heat dissipation from internally generated heat to the outside is improved. Moreover, compared to the case of lower wear resistance, the component life can be extended. Furthermore, it can also reduce noise levels.

[0414] The raw material forming the outer pin 617 of the main bearings 624 and 626 can be a raw material with higher wear resistance than the resin forming the annular surface 649a and the outer peripheral surface 649b of the inner ring, and with higher thermal conductivity than the resin forming the annular surface 649a and the outer peripheral surface 649b of the inner ring. It can also be a metallic material, a non-metallic material, a high-rigidity material, or a material with high thermal conductivity.

[0415] The outer pins 617 constituting the main bearings 624 and 626 in this embodiment can also be formed of ferrous metals such as bearing steel, aluminum metals, light metals such as aluminum, magnesium, beryllium, and titanium, or composite materials thereof. Alternatively, the outer pins 617 can also be formed of ceramics or the like. Furthermore, the gear carriers 618 and 620, housing 622, etc., are formed of resin, thereby achieving a balance between lightweighting and mechanical strength in the reducer 600.

[0416] The high-speed rotation before deceleration is input to the input shaft 612 and the eccentric bearing 630 and input shaft bearing 634, which are arranged in contact with the input shaft 612. Therefore, when the temperature rise of the input shaft 612, the eccentric bearing 630, and the input shaft bearing 634 is relatively large and their heat resistance is low, the permissible input speed decreases. Therefore, the input shaft 612, the input shaft bearing 634, and the eccentric bearing 630 can also be formed of a metal such as an ferrous metal. In this case, the decrease in the permissible input speed can be suppressed.

[0417] Furthermore, since a large torsional stress is applied to the input shaft 612, it is desirable that the input shaft 612 be formed of a material with higher stiffness than the gear carriers 618 and 620. The input shaft 612 may also be formed of a ferrous metal with higher torsional strength than aluminum. As a ferrous metal, carbon steel, bearing steel, stainless steel, etc., can be used depending on the desired properties.

[0418] To ensure the rotational transmission of the external gear 614, it is desirable that the gear carrier pin (inner pin) 638 have high rigidity. Furthermore, to ensure the connection strength between the first gear carrier 618 and the second gear carrier 620, it is desirable that the gear carrier pin 638 have high rigidity. For these considerations, the gear carrier pin 638 and the bolt 638a can also be made of metal. In this example, the gear carrier pin 638 can be made of a ferrous metal.

[0419] This explains the operation of the reducer 600 configured as described above.

[0420] If rotational power is transmitted from the drive device to the input shaft 612, the eccentric portion 612a of the input shaft 612 rotates about the central axis 6La of the input shaft 612. As a result, the external gear 614 oscillates using the eccentric portion 612a. The external gear 614 oscillates by rotating its own axis about the rotational center line of the input shaft 612. As the external gear 614 oscillates, the meshing position of the external gear 614 and the outer pin 617 of the internal gear 616 shifts sequentially. Consequently, for each revolution of the input shaft 612, the rotation of one of the gears, the external gear 614 and the internal gear 616, is equivalent to the difference between the number of teeth on the external gear 614 and the number of outer pins 617 on the internal gear 616. Figure 14 , Figure 15 In the embodiment shown, due to the rotation of the external gear 614, a decelerated rotation is output from the first gear carrier 618 or the housing 622.

[0421] At this time, in the main bearings 624 and 626, the portion of the outer pin 617 exposed from the pin groove 616b moves relative to the circumferential recesses 646 and 647 as the gear carriers 618 and 620 and the housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c of the outer pin 617 contacts the outer circumferential surface 649b in a linear manner in the direction of the central axis 6La.

[0422] In this embodiment of the reducer 600, the outer pin 617 serves as both an internal gear pin for the internal teeth of the internal gear 616 and a roller for the main bearings 624 and 626. Therefore, the number of constituent parts can be reduced, resulting in miniaturization and weight reduction of the reducer 600. In particular, since there is no need to construct the main bearing as a separate component on the outside of the outer pin 617, the thickness dimension of the reducer 600 can be reduced. Furthermore, since the outer pins 617 are arranged to cover most of the thickness direction near the outer periphery of the reducer 600, sufficient strength is provided to prevent malfunctions caused by deformation.

[0423] In this embodiment, the reducer 600 does not have any metal components heavier than resin, except for the outer pin 617, thus enabling further weight reduction. Furthermore, when one component is made of resin, and the other component is formed from a raw material with higher wear resistance and thermal conductivity than the resin component, weight reduction, high rigidity, high heat dissipation, and improved operational reliability can be achieved.

[0424] The reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0425] (10th Embodiment)

[0426] The tenth embodiment of the speed reducer of the present invention will be described with reference to the accompanying drawings.

[0427] Figure 16 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from the 9th embodiment lies in the points related to the outer pin; other structures corresponding to those in the 9th embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0428] In this embodiment, the reducer 600, such as Figure 16 As shown, enlarged diameter portions 617f are formed at both ends of the outer pins 617 of the main bearings 624 and 626. The enlarged diameter portions 617f are formed in the portions exposed from the pin grooves 616b. The portion of the outer pin 617 that is received in the pin grooves 616b is configured with the same structure as in the ninth embodiment.

[0429] The diameter of the enlarged portion 617f is larger than the diameter of the portion of the outer pin 617 that is received in the pin groove 616b. The diameter of the enlarged portion 617f is equal along its entire length in the direction along the central axis 6La. Furthermore, the enlarged portions 617f formed at both ends of the outer pin 617 are all of the same shape.

[0430] The end face 617b of the outer pin 617 at the expanded diameter portion 617f is slightly separated from or in contact with the annular surface 649a. The circumferential surface 617c at the expanded diameter portion 617f is in contact with the outer circumferential surface 649b. Simultaneously, the radial positions of the circumferential recesses 646 and 647 are close to the central axis 6La. Similarly, the radial dimension of the annular surface 649a also increases.

[0431] Compared to the ninth embodiment, the cross-sectional shapes of the circumferential recess 646 and the enlarged diameter portion 617f are correspondingly increased in the radial direction.

[0432] The circumferential surface 617c of the expanded diameter portion 617f rolls into contact with the outer circumferential surface 649b and moves relative to the outer circumferential surface 649b as the gear carriers 618 and 620 and the housing 622 rotate relative to each other about the central axis 6La. The circumferential surface 617c of the outer pin 617 remains in contact with the outer circumferential surface 649b in a linear manner in the direction of the central axis 6La.

[0433] exist Figure 16 In the reducer 600 of this embodiment, the diameter of the circumferential surface 617c of the expanded diameter portion 617f is larger than that of the circumferential surface 617c in the ninth embodiment. Therefore, when the rotational speed at the outer pin 617 is the same, the circumferential speed of the circumferential surface 617c increases proportionally to the diameter.

[0434] As a prerequisite, the outer pin 617 rotates at a constant speed as the gear carriers 618, 620 and housing 622 rotate relative to each other about the central axis 6La, and as the inner pin of the inner gear 616 contacts the outer gear 614.

[0435] The rotating circumferential surface 617c contacts the outer circumferential surface 649b of the circumferential recesses 646 and 647, thereby enabling the circumferential surface 617c to roll into contact with the outer circumferential surface 649b under ideal rotational conditions.

[0436] However, when the circumferential speed of the outer circumferential surface 617c differs significantly from that of the outer circumferential surface 649b, the circumferential surface 617c and the outer circumferential surface 649b become in sliding contact. Compared to rolling contact, sliding contact may lead to increased wear, increased heat generation, shortened product lifespan, increased noise, and increased failure rate. Therefore, there is a need to improve these aspects.

[0437] exist Figure 16 The reducer 600 of this embodiment, as shown, thickens the outer pin 617 by providing an enlarged diameter portion 617f. Therefore, the sliding contact between the peripheral surface 617c and the outer peripheral surface 649b can be reduced, and a rolling contact state can be maintained. This allows for adjustment of the peripheral speed of the outer pin 617.

[0438] In other words, by providing an enlarged diameter portion 617f to the outer pin 617, it is less susceptible to sliding resistance from the gear carriers 618 and 620, and the outer pin 617 can rotate primarily due to the contact resistance between it and the outer gear 614.

[0439] This allows the rotational speeds of many outer pins 617 to be synchronized, thereby improving the stability of the relative rotation of the gear carriers 618, 620 and the housing 622 about the central axis 6La.

[0440] Furthermore, depending on the diameter of the gear carriers 618, 620 and the housing 622, their relative rotational states about the central axis 6La, the rotational speed of the outer pin 617 is preferably different.

[0441] Thus, by forming an enlarged diameter portion 617f in the outer pin 617, the circumferential speed of the circumferential surface 617c, which contacts the outer circumferential surface 649b, is increased. Therefore, even if the rotational speed of the outer pins 617 is the same, the circumferential speed of the outer pins 617 can be made close to the circumferential speed of the outer circumferential surface 649b. This makes it easier to match the relative rotational speeds between the gear carriers 618 and 620 and the housing 622. Consequently, the efficiency for adjusting the rotational speeds of the numerous outer pins 617 can be improved.

[0442] In other words, in this embodiment of the reducer 600, the circumferential speed at the circumferential surface 617c of the expanded diameter portion 617f is faster than the position that contacts the pin groove 616b.

[0443] The outer pin 617 contacts the outer peripheral surface 649b at a relatively high rotational speed. Therefore, the circumferential speed at which the peripheral surface 617c contacts the outer peripheral surface 649b is ideally consistent at all outer pins 617.

[0444] Among them, the one with a larger relative contact speed has a higher effect on adjusting the speed deviation at the outer pin 617, that is, suppressing the deviation of the circumferential speed. Therefore, by forming the expanded diameter portion 617f, the rotational speed of many outer pins 617 can be made consistent, so that the circumferential speed of all outer pins 617 is the same. Thus, the deviation of the circumferential speed at many outer pins 617 can be suppressed.

[0445] In this embodiment of the reducer 600, the external gear (oscillating gear) 614 meshing with the outer pin 617 on the radially inner side is not affected. Instead, the diameter of the outer pin 617 is increased by expanding the diameter portion 617f, thereby increasing the circumferential speed at the position in contact with the outer peripheral surface 649b. As a result, it is possible to easily make the rotational speed of many outer pins 617 consistent.

[0446] The reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0447] Furthermore, in this embodiment, an enlarged diameter portion 617f is formed at both ends of the outer pin 617, but it is also possible to form an enlarged diameter portion 617f only on one side.

[0448] (11th Embodiment)

[0449] The 11th embodiment of the speed reducer of the present invention will be described with reference to the accompanying drawings.

[0450] Figure 17 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from the 10th embodiment lies in the points related to the division of the gear carrier. Other structures corresponding to those in the 10th embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0451] In this embodiment, the reducer 600, such as Figure 17 As shown, the first gear carrier (shaft support) 618 is divided into two parts along the central axis 6La. Specifically, as in... Figure 17 As indicated by the dashed line, the dividing plane can be aligned with the central axis 6La as its normal and with the annular plane 649a.

[0452] The first gear carrier (shaft support) 618 is divided into an inner shaft support 618a arranged to surround the internal space of the reducer 600 and an outer shaft support 618b arranged on the outside of the reducer 600.

[0453] The inner shaft bracket 618a is configured to surround the internal space of the reducer 600. The periphery of the inner shaft bracket 618a is aligned with the outer peripheral surface 649b. The thickness of the inner shaft bracket 618a is set to be equal to the axial dimension of the outer peripheral surface 649b.

[0454] The outer shaft bracket 618b is disposed on the outside of the reducer 600. A portion of the periphery of the outer shaft bracket 618b is aligned with the annular surface 649a.

[0455] The first gear carrier (shaft support) 618 is configured such that the inner shaft support 618a and the outer shaft support 618b overlap in the direction along the central axis 6La.

[0456] Similarly, the second gear carrier (retaining bracket) 620 can also be divided into two in the direction of the central axis 6La. In this case, as in Figure 17 As shown by the dashed line, the dividing plane can be aligned with the central axis 6La as the normal and with the annular plane 649a.

[0457] The second gear carrier (retaining bracket) 620 is divided into an inner retaining bracket 620a arranged to surround the internal space of the reducer 600 and an outer retaining bracket 620b arranged on the outside of the reducer 600.

[0458] The inner retaining bracket 620a is configured to surround the internal space of the reducer 600. The periphery of the inner retaining bracket 620a is aligned with the outer peripheral surface 649b. The thickness of the inner retaining bracket 620a is set to be equal to the axial dimension of the outer peripheral surface 649b.

[0459] An outer retaining bracket 620b is disposed on the outside of the reducer 600. A portion of the periphery of the outer retaining bracket 620b is aligned with the annular surface 649a.

[0460] The second gear carrier (holding bracket) 620 is configured such that the inner holding bracket 620a and the outer holding bracket 620b overlap in the direction along the central axis 6La.

[0461] The inner shaft bracket 618a, the outer shaft bracket 618b, the inner retaining bracket 620a, and the outer retaining bracket 620b are all connected to the gear carrier pin (inner pin) 638 by bolts 638a.

[0462] When assembling the reducer 600 of this embodiment, the input shaft 612 and its surrounding components, the outer pin 617, and the outer gear 614 are housed in the housing 622.

[0463] In this state, the inner shaft bracket 618a and the inner retaining bracket 620a are inserted in such a way that they contact the enlarged diameter portion 617f of the plurality of outer pins 617.

[0464] Next, the gear carrier pin 638 is inserted into the gear carrier pin hole 639, and the outer shaft bracket 618b and the outer retaining bracket 620b are brought into contact with or close to the end face 617b of the outer pin 617. Then, the inner shaft bracket 618a and the outer shaft bracket 618b, as well as the inner retaining bracket 620a and the outer retaining bracket 620b, are connected to the gear carrier pin (inner pin) 638 using bolts 638a.

[0465] Therefore, when assembling the reducer 600, it will not be affected by the expansion portion 617f formed in the outer pin 617, which can shorten the assembly time and improve efficiency.

[0466] Furthermore, the outer peripheral surface 649b for contact with the outer pin 617 can be formed simply by machining the outer peripheral contours of the inner shaft bracket 618a and the inner retaining bracket 620a. As a result, the ease of machining is improved.

[0467] Furthermore, when the gear carrier pin 638 and the first gear carrier (shaft support) 618 are integrated, the gear carrier pin 638 and the inner shaft support 618a can be integrated.

[0468] The reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0469] Furthermore, in this embodiment, for example like the 9th embodiment, it is also possible to configure a structure in which the expansion portion 617f is not provided in the outer pin 617.

[0470] (12th implementation)

[0471] The 12th embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0472] Figure 18 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from embodiments 9 to 11 lies in the points related to the main bearing. Other structures corresponding to those in embodiments 9 to 11 are labeled with the same reference numerals, and their descriptions are omitted.

[0473] In this embodiment, the reducer 600, such as Figure 18 As shown, a crossed roller bearing is provided at one end of the outer pin 617 as a main bearing 624. The other end of the outer pin 617 also serves as a main bearing 626, similar to that in embodiments 9 to 11.

[0474] In the main bearing 626, the pin groove 616b covers the entire length of the outer pin 617 along the central axis 6La. The pin groove 616b extends from the radially outer side of the outer gear 614 to the radially outer side of the second gear carrier 620.

[0475] Therefore, the housing 622, which integrally forms the internal gear 616, also extends radially outward from the second gear carrier 620 in the same way as the pin groove 616b.

[0476] Thus, the outer pin 617 and pin groove 616b constituting the internal teeth of the internal gear 616 are equivalent to the inner circumferential surface 648 of the main bearing 626.

[0477] The main bearing 624 has an outer ring 624a that rotates integrally with the housing 622, an inner ring 624b that rotates integrally with the first gear carrier 618, and rollers 624c that serve as rolling elements. V-grooves with opposing cross-sections are formed on the opposing surfaces between the outer ring 624a and the inner ring 624b. Between the outer ring 624a and the inner ring 624b, a plurality of rollers 624c are arranged alternately in a manner orthogonal to their axes, utilizing the V-grooves.

[0478] The main bearing 624, configured as a crossed roller bearing, is adjacent to the output side of the outer pin 617 along the direction of the central axis 6La. The outer ring 624a is adjacent to the output end of the outer pin 617. The inner ring 624b is configured separately from the external gear 614 located on the output side along the direction of the central axis 6La.

[0479] The main bearing 624, which is a crossed roller bearing, is preferably made of metal.

[0480] The outer ring 624a is mounted in a recess formed in the housing 622. In this embodiment, the member 650, which serves as a fixing member or an output member, is mounted to the housing 622 using bolts 650a. The outer ring 624a of the main bearing 624 is held in place by the portion of the housing 622 where the bolts 650a are mounted.

[0481] In other words, the housing 622 and the integral component 650 covering the outer ring 624a of the main bearing 624. The inner ring 624b of the main bearing 624 is mounted radially outward of the first gear carrier 618.

[0482] In the reducer 600 of this embodiment, the gear carrier pin 638 has a flange portion 638b at its output side end. The output side end of the gear carrier pin 638 passes through the hole 618d of the first gear carrier 618. The output side end of the gear carrier pin 638 is fixed to the first gear carrier 618 by means of the flange portion 638b.

[0483] The input-side end of the gear carrier pin 638 is inserted into the hole 620d of the second gear carrier 620. The input-side end of the gear carrier pin 638 has an external thread 638e, which is fixed to the second gear carrier 620 by a nut 638d. The gear carrier pin 638 is surrounded by a tubular inner roller 637.

[0484] The gear carrier pin (inner pin) 638 is inserted into and passes through the gear carrier pin hole (inner pin hole) 639 formed by the external gear 614 with a gap.

[0485] In this embodiment, an input shaft bearing 634 supports the output side end of the input shaft 612. A motor shaft (not shown) or the like is connected to the input side of the input shaft 612. Alternatively, a structure can be provided in which the input side of the input shaft 612 is supported by a bearing such as a motor shaft. Therefore, a bearing is not shown on the input side of the input shaft 612.

[0486] In this embodiment, the main bearing 624 on the output side is a crossed roller bearing. Therefore, rolling contact can reduce resistance, thereby stabilizing the relative rotation between the gear carriers 618 and 620 and the housing 622. In particular, the positional stability of the gear carriers 618 and 620 and the housing 622 in the thrust direction during rotation can be improved.

[0487] The reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0488] (13th implementation)

[0489] The 13th embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0490] Figure 19 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from the 12th embodiment lies in the points related to the main bearing. Other structures corresponding to those in the 12th embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0491] In this embodiment, the reducer 600, such as Figure 19 As shown, the input end of the outer pin 617 also serves as the main bearing 626, just like in the 12th embodiment.

[0492] In the main bearing 626, the pin groove 616b, which functions as the inner circumferential surface 648, does not cover the entire length of the outer pin 617 along the central axis 6La. That is, the pin groove 616b is located radially outside the outer gear 614, but not radially outside the second gear carrier 620.

[0493] The housing 622, like the pin groove 616b, covers the radially outer side of the external gear 614. The housing 622 does not extend radially outwards to the second gear carrier 620. The housing 622 may also be positioned near the inner circumferential side of the central axis 6La, such that the input-side end face 622a is flush with the output-side end face of the second gear carrier 620. Therefore, the outer pin 617 does not contact the pin groove 616b radially outwards to the second gear carrier 620.

[0494] In this embodiment, the reducer 600 housing 622 is not located radially outside the second gear carrier 620, thus enabling further weight reduction.

[0495] Furthermore, the reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0496] (14th embodiment)

[0497] The 14th embodiment of the speed reducer of the present invention is described with reference to the accompanying drawings.

[0498] Figure 20 This is a cross-sectional view along the axial direction of the reducer according to this embodiment. In this embodiment, the difference from the 12th and 13th embodiments lies in the points related to the main bearing. Other structures corresponding to those in the 12th and 13th embodiments are labeled with the same reference numerals, and their descriptions are omitted.

[0499] In this embodiment, the reducer 600, such as Figure 20 As shown, the input end of the outer pin 617 also serves as the main bearing 626, similar to the 13th embodiment, and is not covered by the pin groove 616b corresponding to the inner circumferential surface 648. An enlarged diameter portion 617f is provided at the input end of the outer pin 617, similar to the 10th embodiment.

[0500] In the outer pin 617 of the main bearing 626, an enlarged diameter portion 617f is provided on the input side where it does not contact the pin groove 616b. In the outer pin 617, the enlarged diameter portion 617f is provided on the input side of the portion in the axial direction that is closer to the end face 622a of the housing 622.

[0501] An enlarged diameter portion 617f is provided on the portion of the outer pin 617 that protrudes from the pin groove 616b. The enlarged diameter portion 617f is sandwiched between an end face 622a and an annular face 649a in the direction of the central axis 6La. A portion of the enlarged diameter portion 617f protrudes outside the circumferential recess 647 in the direction of the central axis 6La.

[0502] Therefore, on the output side of the reducer 600, the position setting in the thrust direction is stabilized by using the main bearing 624, which is a cross roller bearing, and the rotational stability of the housing 622 and the gear carriers 618 and 620 is ensured by using the main bearing 624, which is made of metal.

[0503] On the input side of the reducer 600, the output side of the expanded diameter portion 617f is limited by the end face 622a in the direction of the central axis 6La, and the input side is limited by the annular surface 649a in the direction of the central axis 6La. This allows for limitation of the housing 622 and the gear carriers 618 and 620 in the direction of the central axis 6La.

[0504] Therefore, it can improve the operational stability of the reducer 600.

[0505] The reducer 600 according to this embodiment can achieve the same effect as the various embodiments described above.

[0506] In this invention, the structures in the above embodiments can be combined individually.

[0507] In addition, PAEK (Polyaryletherketones) also includes PEK (polyetherketone), PEKK (polyetherketoneketone), PEKKEK (polyetherketoneketone), etc.

[0508] Industrial availability

[0509] As a flexible application example of the present invention, service robots, collaborative work robots, and assistive devices that are physically close to humans can be listed, which can achieve the safety effect brought about by their lightweight nature.

Claims

1. A speed reducer, wherein, This reducer has the following features: The shell that surrounds the main axis; An internal gear having: a resin-made internal gear body integral with the housing; and a plurality of external pins rotatably disposed in pin grooves formed in the internal gear body; An external gear that meshes with the internal gear; An eccentric body that causes the external gear to oscillate; A resin gear carrier that rotates relative to the housing; as well as The main bearing supports the gear carrier so that it can rotate freely relative to the housing. The main bearing is configured as a sliding bearing, which has an inner circumferential sliding surface formed on the inner circumferential surface of a metal ring integrally rotating with the housing, and an outer circumferential sliding surface formed on the outer circumferential surface of the gear carrier and in contact with the inner circumferential sliding surface. The metal ring having the inner circumferential sliding surface is formed from a raw material having a higher thermal conductivity and higher wear resistance than the resin having the outer circumferential sliding surface of the gear carrier. The outer pin is formed from a raw material with a higher thermal conductivity and wear resistance than the resin of the inner gear body.

2. The reducer according to claim 1, wherein, The inner circumferential sliding surface is positioned to overlap with the outer pin in the direction along the main axis.

3. The reducer according to claim 1 or 2, wherein, The inner and outer sliding surfaces have grooves that do not communicate with the internal space for receiving the external gear.

Images