reducer

Abstract

The reducer includes: an annular external gear having multiple external teeth arranged circumferentially to form multiple through holes; an input shaft passing through a space surrounded by the inner circumferential surface of the external gear; a bearing disposed between the external gear and the input shaft; an annular internal gear having multiple internal teeth meshing with the external gear and surrounding the outer circumferential surface of the external gear; multiple internal pins passing axially through the multiple through holes; and an internal pin retainer holding both ends of the internal pins. The internal pin retainer includes: a first retainer portion having an annular retaining portion holding a first end of the internal pin; a second retainer portion having an annular retaining portion holding a second end of the internal pin; and a column portion connecting the first retainer portion and the second retainer portion and passing through the through holes. The reducer also includes a fixing member inserted into the interior of the column portion from its end face, fixing the end face of the column portion to the first retainer portion or the second retainer portion.

Description

Technical Field

[0001] This invention relates to a speed reducer. This application claims priority to Japanese Application No. 2021-087529, filed May 25, 2021, and invokes the entire contents of the aforementioned Japanese application. Background Technology

[0002] Traditionally, speed reducers have been used in drive control units for wheels in mobile devices, robots, or machine tools. This technology is described, for example, in Patent Document 1.

[0003] The reducer described in Patent Document 1 includes: an input shaft having a pair of eccentric portions; a pair of cycloidal gears in contact with the eccentric portions; a hub constituting an output shaft; an output shaft pin retainer; a plurality of outer peripheral pins; an outer peripheral pin retainer holding the outer peripheral pins; and an inner peripheral pin supported by the hub. The inner peripheral pin includes: a shaft; an outer ring rotatably disposed relative to the shaft; and a roller rolling between the shaft and the outer ring. Both ends of the shaft are fixed to the hub and the output shaft pin retainer by fixing bolts.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-48852 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] As described above, in the reducer disclosed in Patent Document 1, both ends of the inner circumferential pin shaft are fixed to the hub and output shaft pin retainer by fixing bolts. Therefore, holes for inserting fixing bolts need to be formed at the ends of the inner circumferential pin shaft. In this case, because it is difficult to make the inner circumferential pin shaft thinner, it is difficult to reduce the radial dimension of the reducer. Therefore, there is still room for improvement in the compactness of existing reducers.

[0009] The purpose of this invention is to provide a speed reducer that can achieve a compact design.

[0010] means for solving problems

[0011] The transmission of the present invention comprises: an external gear, which is annular in shape and has a plurality of external teeth arranged circumferentially on its outer peripheral surface, and a plurality of through holes arranged circumferentially to form a through hole extending axially; an input shaft extending axially through a space surrounded by the inner peripheral surface of the external gear; a bearing disposed between the external gear and the input shaft, holding the input shaft so that it can rotate relative to the external gear circumferentially; an internal gear, which is annular in shape and has a plurality of internal teeth arranged circumferentially on its inner peripheral surface and meshing with the external teeth, and surrounding the outer peripheral surface of the external gear; a plurality of inner pins extending axially through the plurality of through holes; and an inner pin retainer holding both ends of the inner pins, forming a space for the input shaft to pass through. The inner circumferential pin retainer includes: a first retainer portion having an annular retaining portion for retaining a first end of the inner circumferential pin; a second retainer portion having an annular retaining portion for retaining a second end of the inner circumferential pin on the side opposite to the first end; and a post portion connecting the first retainer portion and the second retainer portion, arranged circumferentially spaced apart, and passing through the aforementioned through hole. The aforementioned reducer further includes: a fixing member inserted into the interior of the post portion from its end face, fixing the end face of the post portion to the first retainer portion or the second retainer portion.

[0012] The effects of the invention

[0013] According to the present invention, a speed reducer capable of achieving compactness can be provided. Attached Figure Description

[0014] Figure 1 This is a perspective view showing the external structure of the cycloidal reducer according to the first embodiment.

[0015] Figure 2 This is a front view of the cycloidal reducer of the first embodiment, viewed from the input shaft side.

[0016] Figure 3 This is a rear view of the cycloidal reducer of the first embodiment, viewed from the output shaft side.

[0017] Figure 4 It is along Figure 2 A cross-sectional view of line segment IV-IV in the diagram.

[0018] Figure 5 It is along Figure 4 A cross-sectional view of line segment VV in the diagram.

[0019] Figure 6 It is a three-dimensional diagram showing the structure of the input shaft.

[0020] Figure 7 It is a three-dimensional diagram showing the structure of the pressing component.

[0021] Figure 8 This is a top view showing the structure of the cycloidal gear.

[0022] Figure 9 This is a three-dimensional diagram showing the structure of the outer peripheral pin cage.

[0023] Figure 10 This is a three-dimensional diagram showing the structure of the inner circumferential pin.

[0024] Figure 11 It is a three-dimensional diagram showing the cage-like structure in which the inner circumferential pin is held by the inner circumferential pin cage.

[0025] Figure 12 yes Figure 11 A magnified view of region XII in the image.

[0026] Figure 13 This is a perspective view showing the structure of the second cage section and the column section.

[0027] Figure 14 This is a three-dimensional diagram showing the structure of the internal peripheral pin lubrication component.

[0028] Figure 15 This is a perspective view showing the external structure of the cycloidal reducer according to the second embodiment.

[0029] Figure 16 It is along Figure 15 A cross-sectional view of line segment XVI-XVI in the diagram. Detailed Implementation

[0030] [Summary of Implementation Methods]

[0031] The reducer of the present invention comprises: an annular external gear having a plurality of external teeth arranged circumferentially on its outer circumferential surface and a plurality of through holes arranged circumferentially and extending axially; an input shaft extending axially through a space surrounded by the inner circumferential surface of the external gear; a bearing disposed between the external gear and the input shaft and holding the input shaft so that it can rotate relative to the external gear circumferentially; an internal gear having a plurality of internal teeth arranged circumferentially on its inner circumferential surface and meshing with the external gear, and surrounding the outer circumferential surface of the external gear; a plurality of inner pins extending axially through the plurality of through holes; and an inner pin retainer holding the two ends of the inner pins, forming a space through which the input shaft passes. The inner circumferential pin retainer includes: a first retainer portion having an annular retaining portion for retaining a first end of the inner circumferential pin; a second retainer portion having an annular retaining portion for retaining a second end of the inner circumferential pin on the side opposite to the first end; and a post portion connecting the first retainer portion and the second retainer portion, and being arranged circumferentially spaced apart and passing through the aforementioned through hole. The reducer further includes: a fixing member inserted into the interior of the post portion from its end face, fixing the end face of the post portion to the first retainer portion or the second retainer portion.

[0032] In the aforementioned reducer, a fixing member inserted into the interior of the column from its end face is used to fix the end face to either the first or second retainer portion. Therefore, unlike conventional reducers, it is not necessary to insert the fixing member into the shaft of the inner circumferential pin. Consequently, compared to conventional reducers, the aforementioned reducer allows for a thinner inner circumferential pin and a reduction in radial dimensions, achieving a more compact design.

[0033] In the aforementioned reducer, the cross-sectional shape of the column portion perpendicular to its length direction can be an arc extending circumferentially. The multiple through holes formed on the external gear can be elongated holes extending circumferentially. According to this structure, because the area of ​​the end face of the column portion can be increased, the restrictions on the position of the insertion holes for the fixing members are reduced. As a result, the design freedom of the reducer is increased.

[0034] In the aforementioned reducer, multiple inner circumferential pins can be configured to clamp the column portion in the circumferential direction. These inner circumferential pins can be rolling bearings or sliding bearings. According to this structure, since friction between the two circumferential sides of the column portion and the inner surface of the through-hole of the external gear can be suppressed, the friction between these two sides and the inner surface of the through-hole can be reduced. Furthermore, since the inner circumferential pins, acting as rolling or sliding bearings, rotate by contacting the inner surface of the through-hole, the increase in the rotational torque of the input shaft can be suppressed.

[0035] The aforementioned reducer may also include a lubrication member disposed inside the through hole formed on the external gear and in contact with the inner circumferential pin. According to this structure, because the inner circumferential pin can be lubricated, friction between the outer circumferential surface of the inner circumferential pin and the inner surface of the through hole of the external gear can be reduced. Therefore, losses caused by this friction can be reduced, and the increase in the rotational torque of the input shaft can be suppressed.

[0036] In the reducer, the lubrication member, in a cross-section cut with a plane perpendicular to the axial direction, may include: a radially extending base portion; a first protrusion protruding from a first end of the base portion; a second protrusion protruding from a second end of the base portion opposite to the first end; and a third protrusion protruding between the first and second ends of the base portion. The lubrication member is oscillating to achieve a first contact state and a second contact state. The first contact state is a state in which the first and third protrusions are in contact with the inner circumferential pin and the second protrusion is separated from the inner circumferential pin. The second contact state is a state in which the second and third protrusions are in contact with the inner circumferential pin and the first protrusion is separated from the inner circumferential pin. According to this structure, the lubrication member can be made to contact the inner circumferential pin at the first to third protrusions. Therefore, compared to the case where the lubrication member is in full contact with the inner circumferential pin, torque loss and temperature rise can be suppressed.

[0037] In the aforementioned reducer, a groove for accommodating a lubrication component can be formed in the column portion. The cross-sectional shape of this groove, perpendicular to its length, can correspond to the shape of the lubrication component. According to this structure, the lubrication component can smoothly oscillate within the groove in the column portion.

[0038] [Specific examples of implementation methods]

[0039] Next, embodiments of the speed reducer of the present invention will be described with reference to the accompanying drawings. In the following drawings, the same or corresponding parts are given the same reference numerals and will not be described again.

[0040] (First Implementation)

[0041] First, the structure of the cycloidal reducer 1 (hereinafter simply referred to as "reducer 1") according to the first embodiment will be described. Reducer 1 is used, for example, in the joint part of a robot, the drive control unit of the wheel in a moving device, etc. Figure 1 This is a perspective view showing the external structure of reducer 1. Figure 2 This is a front view of the reducer 1 as seen from the input shaft 10 side. Figure 3 This is a rear view of the reducer 1 viewed from the output shaft 53 side. Figure 4 It is along Figure 2 A cross-sectional view of line segment IV-IV in the diagram. Figure 5 It is along Figure 4 A cross-sectional view of line segment VV in the diagram. (See also...) Figure 4 As shown, the reducer 1 mainly includes: an input shaft 10; a first external gear 20 and a second external gear 21 (external gears); a first eccentric bearing 13 and a second eccentric bearing 14 (bearings); multiple peripheral pins 31 and peripheral pin cages 30 (internal gears); an inner peripheral pin cage 40 and a main bearing 50. These components will be described in detail below. Furthermore, in this embodiment, a lubricant such as grease is pre-filled into the bearing components.

[0042] The input shaft 10 is a hollow cylindrical shape and extends along the axial direction D1. For example... Figure 4 As shown, the input shaft 10 includes a first end 10A and a second end 10B on the opposite side of the first end 10A along the axial direction D1. The second end 10B is the end opposite to the output shaft 53 and protrudes further outward along the axial direction D1 than the end face 40A of the inner circumferential pin retainer 40. A drive motor (not shown) is mounted on the second end 10B, and by driving the motor, the input shaft 10 rotates about the shaft. Furthermore, the input shaft is not limited to a hollow shaft and can also be a solid shaft.

[0043] The input shaft 10 includes: a first shaft portion 17 including a first end portion 10A; a second shaft portion 18 including a second end portion 10B; and a third shaft portion 19 connecting the first shaft portion 17 and the second shaft portion 18. The outer diameter of the third shaft portion 19 is larger than the outer diameter of the first shaft portion 17, and the outer diameter of the second shaft portion 18 is larger than the outer diameter of the third shaft portion 19. That is, the outer diameter of the input shaft 10 increases in a stepwise manner from the first end portion 10A to the second end portion 10B. On the other hand, the inner diameters of the first to third shaft portions 17 to 19 are all the same.

[0044] like Figure 4 As shown, the third shaft portion 19 is inserted into the inner rings of the first support bearing 12, the first eccentric bearing 13, and the second eccentric bearing 14. The first shaft portion 17 is inserted into the inner ring of the second support bearing 15. The input shaft 10 is supported at both ends by the first support bearing 12 and the second support bearing 15. The first eccentric bearing 13 is disposed between the first external gear 20 and the input shaft 10 (third shaft portion 19), holding the input shaft 10 so that it can rotate relative to the first external gear 20 in the circumferential direction. The second eccentric bearing 14 is disposed between the second external gear 21 and the input shaft 10 (third shaft portion 19), holding the input shaft 10 so that it can rotate relative to the second external gear 21 in the circumferential direction. A keyway 19A for inserting a key 11 is formed on the outer circumferential surface of the third shaft portion 19, extending axially along D1. The inner rings of the first eccentric bearing 13 and the second eccentric bearing 14 are fixed to the input shaft 10 by the key 11.

[0045] like Figure 4 As shown, the first support bearing 12, the first eccentric bearing 13, and the second eccentric bearing 14 are arranged sequentially from the second end 10B to the first end 10A. Each inner ring is clamped in the axial direction D1 by the stepped end face between the second shaft portion 18 and the third shaft portion 19 and the pressing member 23. The pressing member 23 is mounted on the outer circumferential surface of the input shaft 10 (third shaft portion 19) by fixing screws 24. A plurality of pressing members 23 (three in this embodiment) are provided at intervals in the circumferential direction of the input shaft 10.

[0046] An annular groove in which a retaining ring 16 is disposed is formed on the outer peripheral surface of the first shaft portion 17. For example... Figure 4 As shown, the inner ring of the second support bearing 15 is held in the axial direction D1 by the stepped end face between the first shaft portion 17 and the third shaft portion 19 and the retaining ring 16.

[0047] Figure 6 This is a perspective view showing the structure of the input shaft 10 into which each bearing is inserted. Figure 7 This is a three-dimensional view showing the structure of the pressing component 23. For example... Figure 6 As shown, the retaining ring 16 is a circular annular (C-shaped) component with a cutout 16A formed in a portion of its circumference. Figure 7As shown, the pressing member 23 has a U-shaped opening to allow the insertion of a fixing screw. The upper surface 23A of the pressing member 23 is an inclined surface (an inclined surface relative to a surface perpendicular to the thickness direction of the pressing member 23), and its lower surface 23B forms a curved surface along the outer peripheral surface of the input shaft 10.

[0048] The first support bearing 12, the first eccentric bearing 13, and the second eccentric bearing 14 are, for example, cylindrical roller bearings. The first eccentric bearing 13 and the second eccentric bearing 14 are fixed to the input shaft 10 with their eccentric phases offset by 180°. Each of the first eccentric bearing 13 and the second eccentric bearing 14 includes an eccentric inner ring, cylindrical rollers (rolling elements), a cylindrical outer ring, and a cage. The cage can be made of lightweight resin, but is not limited to this. For example, a metal cage can also be used in the first eccentric bearing 13 and the second eccentric bearing 14.

[0049] like Figure 4 As shown, each inner ring of the first eccentric bearing 13 and the second eccentric bearing 14 includes a pair of flanges that restrict the movement of the cylindrical rollers in the axial direction D1. Furthermore, the inner ring is fixed to the outer circumferential surface of the input shaft 10 by a key 11, thereby preventing rotation relative to the input shaft 10. In this embodiment, no seal is provided on the first support bearing 12, but this is not a limitation; a seal may also be provided. Additionally, the second support bearing 15 is, for example, a deep groove ball bearing with a seal, but this is not a limitation; it may also be a bearing without a seal.

[0050] The first external gear 20 and the second external gear 21 are cycloidal gears. The first external gear 20 engages with the outer ring of the first eccentric bearing 13 from the outer side of the radial direction D2. The second external gear 21 engages with the outer ring of the second eccentric bearing 14 from the outer side of the radial direction D2.

[0051] Figure 8 This is a top view of the first external gear 20. (See attached image.) Figure 8 As shown, the first external gear 20 is an annular component with multiple external teeth 27 arranged circumferentially on its outer circumferential surface, and multiple elongated holes 26 (through holes) arranged circumferentially and extending axially. A central hole 25 (space) surrounded by an inner circumferential surface 20A is formed on the first external gear 20, and the input shaft 10 (… Figure 4 ) Through the central hole 25.

[0052] Multiple (eight in this embodiment) elongated holes 26 are formed to extend circumferentially and surround the central hole 25. The central hole 25 is a circular hole. Furthermore, the first eccentric bearing 13 can be omitted. Figure 4 The outer ring of the inner circumference 20A serves as the track surface for the cylindrical rollers.

[0053] In this embodiment, the external teeth 27 are parallel to the epicycloid curve, but are not limited to this. Furthermore, the number of external teeth 27 is not particularly limited; they can be appropriately selected to achieve the desired reduction ratio.

[0054] The first external gear 20 is made of steel such as high-carbon chromium bearing steel (SUJ2) or chromium-molybdenum steel (SCM) according to JIS (Japanese Industrial Standards) after heat treatment, but is not limited to these. For example, in addition to aluminum, resin materials such as carbon fiber reinforced plastics (CFRP) can be used as the material for the first external gear 20. Furthermore, since the second external gear 21 is basically the same as the first external gear 20, a detailed description of the second external gear 21 is omitted.

[0055] Export sales 31 ( Figure 4 It is cylindrical in shape extending along the axial direction D1, forming a structure with the external teeth 27 ( Figure 8 The outer peripheral pins 31 are held by the inner peripheral surface of the outer peripheral pin retainer 30 and are arranged circumferentially on the inner peripheral surface. The number of outer peripheral pins 31 is not particularly limited, but in this embodiment, the number of them is one more than the number of outer teeth 27.

[0056] Figure 9 This is a perspective view showing the structure of the outer peripheral pin cage 30. The outer peripheral pin cage 30 surrounds the first external gear 20 and the second external gear 21. Figure 4 The outer peripheral pin retainer 30 is a ring-shaped component. Multiple through holes 30A are formed on the outer peripheral pin retainer 30, extending from the outer peripheral surface to the inner peripheral surface, along the entire circumferential direction. The through holes 30A are formed to achieve weight reduction of the outer peripheral pin retainer 30, and their inner diameter gradually decreases radially inward. Furthermore, the shape and number of through holes 30A are not particularly limited. It should be noted that in the reducer of the present invention, the through holes 30A are not a necessary structure and can be omitted.

[0057] like Figure 9 As shown, a first pin retaining ring 32A and a second pin retaining ring 33A, which are separated from the first pin retaining ring 32A in the axial direction D1, are respectively provided on the inner circumferential surface of the outer peripheral pin retainer 30. Each of the first pin retaining ring 32A and the second pin retaining ring 33A has a plurality of arc-shaped grooves arranged circumferentially and extending in the axial direction D1, and is arranged in a ring shape along the inner circumferential surface of the outer peripheral pin retainer 30. Outer peripheral pin 31 ( Figure 4The first end of the outer peripheral pin 31 is embedded in the groove of the first pin retaining ring 32A, and the second end, on the opposite side of the first end in the axial direction D1, is embedded in the groove of the second pin retaining ring 33A. Thus, the plurality of outer peripheral pins 31 and outer peripheral pin retainers 30 have circumferentially arranged on the inner peripheral surface and are engaged with the outer teeth 27. Figure 8 Multiple meshing internal teeth form an annular internal gear surrounding the outer peripheral surfaces of the first external gear 20 and the second external gear 21. Furthermore, in this embodiment, the outer peripheral pin 31 is arranged with an interval between the slots of the first pin retaining ring 32A and the second pin retaining ring 33A, but this is not a limitation.

[0058] like Figure 4 As shown, the input shaft 10, the first external gear 20, the second external gear 21, and the inner peripheral pin retainer 40 are respectively housed on the inner side of the outer peripheral pin retainer 30 in the radial direction D2. The reducer 1 has a first pin limiting member 33 and a second pin limiting member 34 that restrict the movement of the outer peripheral pin 31 in the axial direction D1. The first pin limiting member 33 is an annular member that is aligned with the first end face of the outer peripheral pin 31 in the axial direction D1. Figure 4 The second pin limiting member 34 is an annular member identical to the first pin limiting member 33, and is opposite to the second end face of the outer peripheral pin 31 in the axial direction D1. Figure 4 (The left end face of the middle) is opposite.

[0059] The reducer 1 has a dustproof outer plate 35, which is fixed to the first end face of the outer peripheral pin retainer 30 (the end face opposite to the main bearing 50) by bolts B2. Figure 4 On the right end face of the middle. For example... Figure 4 As shown, the outer plate 35 extends to a position closer to the inner side of the radial direction D2 than the inner circumferential surface of the outer peripheral pin retainer 30, to block the radial gap D2 between the outer peripheral pin retainer 30 and the inner peripheral pin retainer 40. It should be noted that in the reducer of the present invention, the first pin limiting member 33, the second pin limiting member 34, and the outer plate 35 are all non-essential components and can be omitted.

[0060] The reducer 1 has an outer peripheral pin lubrication member 32. The outer peripheral pin lubrication member 32 is, for example, a member formed by impregnating a porous sintered resin member with a lubricant. The outer peripheral pin lubrication member 32 is disposed on the inner peripheral surface of the outer peripheral pin retainer 30. Figure 4 More specifically, the outer peripheral pin lubrication component 32 is disposed in the portion of the inner peripheral surface of the outer peripheral pin retainer 30 between the first pin retaining ring 32A and the second pin retaining ring 33A. Figure 9 ).

[0061] The outer peripheral pin 31 rotates around the shaft through contact with the first external gear 20 and the second external gear 21. Additionally, the outer peripheral pin 31 contacts the outer peripheral pin lubrication member 32. Therefore, as the outer peripheral pin 31 rotates around its shaft, the outer peripheral pin lubrication member 32 also rotates around the shaft (around the rotational shaft of the reducer 1). Since lubricant can be supplied to the outer peripheral pin 31 through the outer peripheral pin lubrication member 32, the friction between the outer peripheral pin 31 and the first external gear 20 and the second external gear 21 can be reduced. This reduces losses caused by friction and suppresses the increase in the rotational torque of the input shaft 10. It should be noted that in the reducer of the present invention, the outer peripheral pin lubrication member 32 is not an essential component and can be omitted.

[0062] The reducer 1 has multiple (sixteen in this embodiment) inner circumferential pins 60 ( Figure 5 The inner circumferential pin 60 is formed axially through multiple elongated holes 26 on the first external gear 20 and the second external gear 21. Figure 10 This is a perspective view showing the structure of the inner peripheral pin 60 in this embodiment, with the rolling element 63 represented by dashed lines. (As shown...) Figure 10 As shown, the inner circumferential pin 60 is a rolling bearing comprising a cylindrical shaft 61, a pair of annular rings 62, and a plurality of rolling elements 63 (needle rollers). Furthermore, the inner circumferential pin is not limited to a rolling bearing as in this embodiment; for example, it could also be a sliding bearing.

[0063] like Figure 10 As shown, the corners at both ends of the shaft 61 are chamfered, and the shaft 61 is inserted into a pair of outer rings 62. Rolling elements 63 are arranged annularly between the outer circumferential surface of the shaft 61 and the inner circumferential surface of the outer rings 62. The inner circumferential pin 60 includes an outer end face of the outer ring 62 and a thrust washer 64 disposed between the outer rings 62. The thrust washer 64 is made of, for example, a thermoplastic resin such as PEEK (Poly ether ether ketone), but is not limited to this.

[0064] Inner circumferential pin cage 40 ( Figure 4 The inner circumferential pin 60 is held at both ends. A space is formed on the inner circumferential pin retainer 40 for the input shaft 10 to pass through. Figure 4As shown, the inner circumferential pin retainer 40 includes a first retainer portion 41, a second retainer portion 42, and a post portion 43. Thrust washers 22 are disposed between the first external gear 20 and the first retainer portion 41, between the first external gear 20 and the second external gear 21, and between the second external gear 21 and the second retainer portion 42. These thrust washers 22 are made, for example, of a thermoplastic resin such as PEEK. This suppresses wear caused by contact between the external gears and the inner circumferential pin retainer 40, wear caused by contact between the external gears themselves, and prevents overheating. It should be noted that in the reducer of the present invention, the thrust washer is not an essential component and can be omitted.

[0065] Figure 11 This is a perspective view showing the cage-like structure in which the two ends of the axial D1 of the inner circumferential pin 60 are held by the inner circumferential pin retainer 40. Figure 11 The input shaft 10, the first external gear 20, and the second external gear 21 are omitted in the text. Figure 11 As shown, the first retainer portion 41 has an annular retaining portion for retaining the first end of the inner peripheral pin 60.

[0066] Figure 12 yes Figure 11 A magnified view of region XII in the middle. (See image below.) Figure 12 As shown, a plurality of holes 45 for pressing in the first ends of the shaft 61 are formed circumferentially spaced on the first retainer portion 41. The holes 45 penetrate the first retainer portion 41 in the thickness direction. In addition, in order to prevent the shaft 61 from falling out, only the pressed portion of the shaft 61 in the holes 45 is reamed.

[0067] The second retainer portion 42 has an annular retaining portion for retaining the second end of the inner circumferential pin 60 on the side opposite to the first end. For example... Figure 11 As shown, the second retainer portion 42 is an annular portion with approximately the same diameter as the first retainer portion 41, and is separated from the first retainer portion 41 in the axial direction D1. Similar to the first retainer portion 41, a plurality of holes for pressing into the second ends of the inner circumferential pins 60 are formed circumferentially spaced on the second retainer portion 42.

[0068] The column portion 43 connects the first retainer portion 41 and the second retainer portion 42, and is arranged at intervals in the circumferential direction. Figure 11 The column portion 43, together with the inner circumferential pin 60, passes through the elongated hole 26 formed on the first external gear 20 and the second external gear 21. Figure 5 Furthermore, there is no particular limitation on the number of pillars 43, but it is preferred that their number be half the number of inner circumferential pins 60 and more than four.

[0069] Figure 13 This indicates the state after the first retainer portion 41 has been removed from the inner circumferential pin retainer 40. For example... Figure 13 As shown, the cross-sectional shape of the column portion 43, perpendicular to the length direction (axial direction D1), is an arc extending circumferentially. In this embodiment, the second retainer portion 42 and the column portion 43 are integrally formed. The column portion 43 includes an end face 46 on the side opposite to the second retainer portion 42. This end face 46 is fixed to the first retainer portion 41 ( Figure 12 Furthermore, it is not limited to the case where the second retainer portion 42 and the column portion 43 are formed as one piece; the first retainer portion 41, the second retainer portion 42, and the column portion 43 may also be composed of different components.

[0070] The reducer 1 has a plurality of bolts B1 (fixing members) that fix the end face 46 of the column 43 to the first retainer 41 and insert from the end face 46 into the interior of the column 43. Figure 11 and Figure 12 ).like Figure 4 As shown, a bolt hole 41A (through hole) for inserting bolt B1 is formed on the first retainer portion 41. On the other hand, an internal thread hole 43A is formed on the post portion 43, which engages with the external thread formed on the outer peripheral surface of the shaft portion of bolt B1. The internal thread hole 43A is a bottomed hole that opens on one side of the first retainer portion 41 and is formed corresponding to the bolt hole 41A.

[0071] like Figure 5 As shown, the post 43 is inserted into the elongated hole 26 together with a pair of inner circumferential pins 60. More specifically, the plurality of (two) inner circumferential pins 60 are configured to clamp the post 43 from both sides in the circumferential direction. In addition, the inner circumferential pins 60 contact the inner surface of the elongated hole 26.

[0072] The reducer 1 has an inner circumferential pin lubrication member 70 for lubricating the inner circumferential pin 60. Figure 5 The inner circumferential pin lubrication component 70 is disposed inside the elongated hole 26, contacting the outer circumferential surface of the inner circumferential pin 60 (the outer circumferential surface of the outer ring 62). More specifically, as... Figure 5 As shown, grooves extending axially are formed on both sides of the circumferential portion of the column 43. The cross-sectional shape of the groove perpendicular to the axial direction is arc-shaped, and an inner circumferential pin lubrication member 70 is accommodated within the groove. The cross-section of the groove perpendicular to its length direction ( Figure 5 The cross-sectional shape corresponds to the inner circumferential pin lubrication member 70. The inner circumferential pin lubrication member 70 is, for example, a member formed by impregnating a porous sintered resin member with a lubricant, but is not limited to this.

[0073] Figure 14 This is a perspective view showing the structure of the inner circumferential pin lubrication component 70. (Reference) Figure 5 and Figure 14 The cross-section of the inner peripheral pin lubrication component 70 is formed by cutting a plane perpendicular to the axial direction D1. Figure 5The cross-section includes: a base portion 75 extending radially along D2; a first protrusion 72; a second protrusion 73; and a third protrusion 71. The first protrusion 72 protrudes from a first end of the base portion 75. The second protrusion 73 protrudes from a second end of the base portion 75 on the radial D2 direction opposite to the first end. The third protrusion 71 protrudes between the first end and the second end of the base portion 75.

[0074] The aforementioned first to third protrusions are shaped to bulge towards the outer peripheral surface of the inner peripheral pin 60, and each tip is curved. That is, the inner peripheral pin lubrication member 70 is positioned such that the tips of its first to third protrusions face the outer peripheral surface of the inner peripheral pin 60. Additionally, the back surface 74 of the inner peripheral pin lubrication member 70, opposite to the first to third protrusions... Figure 14 ) forms a curved surface, the curved surface being away from the column portion 43 ( Figure 5 The direction of the groove is concave into an arc shape. Therefore, when the drive of the reducer 1 stops, there is a gap between the circumferential side of the column 43 and the inner circumferential pin lubrication member 70.

[0075] The inner circumferential pin lubrication member 70 can swing within the grooves on both sides of the circumferential portion 43 to achieve a first contact state and a second contact state. The first contact state is that the first protrusion 72 and the third protrusion 71 are in contact with the outer circumferential surface of the inner circumferential pin 60, while the second protrusion 73 is separated from the outer circumferential surface of the inner circumferential pin 60. The second contact state is that the second protrusion 73 and the third protrusion 71 are in contact with the outer circumferential surface of the inner circumferential pin 60, while the first protrusion 72 is separated from the outer circumferential surface of the inner circumferential pin 60. More specifically, the inner circumferential pin lubrication member 70 swings along the arc-shaped curved surface formed on both sides of the circumferential portion 43, so that the first protrusion 72 and the second protrusion 73 alternately contact the outer circumferential surface of the inner circumferential pin 60. The inner circumferential pin lubrication member 70 is located on the input shaft 10 along... Figure 5 The first contact state is formed when the inner circumferential pin 60 rotates clockwise. At this time, the outer ring 62 of the inner circumferential pin 60 ( Figure 10 )along Figure 5 It rotates counterclockwise. On the other hand, the inner circumferential pin lubrication member 70 is located along the input shaft 10. Figure 5 The second contact state is formed when the inner circumferential pin 60 rotates counterclockwise. At this time, the outer ring 62 of the inner circumferential pin 60 moves along... Figure 5 Rotate clockwise within.

[0076] If the inner circumferential lubrication member 70 is in complete contact with the outer circumferential surface of the inner circumferential pin 60, i.e., the outer ring 62, the inner circumferential lubrication member 70 will adhere to the outer ring 62, resulting in torque loss and temperature rise. In contrast, by employing a structure in which the first to third protrusions contact the outer ring 62 of the inner circumferential pin 60, the aforementioned adverse conditions can be prevented. It should be noted that in the reducer of the present invention, the inner circumferential lubrication member 70 is not an essential component and can be omitted.

[0077] Main bearing 50 ( Figure 4 For example, crossed roller bearings. Figure 4 As shown, the main bearing 50 includes: an outer ring 51; an inner ring 53; a plurality of rolling elements 52 arranged in annularly between the raceway surface (inner circumferential surface) of the outer ring 51 and the raceway surface (outer circumferential surface) of the inner ring 53; and a seal 54.

[0078] The outer ring 51 is fixed to the second end face (the end face opposite to the first end face) of the outer peripheral pin retainer 30 by bolt B2. Figure 4 (Left end face of the middle). The outer ring 51 and the outer peripheral pin retainer 30 together form a fixed shaft. An insertion hole for the rolling element 52 is formed on the outer ring 51, and a cover 51A is provided to close the insertion hole. Figure 1 The cover 51A can be prevented from falling off using a pin. Furthermore, the cover can be a side cover, and is not limited to being mounted on the outer ring 51. Additionally, it is not limited to using a pin extending axially along D1; either a pin extending circumferentially or a bolt can be used to prevent the cover from falling off.

[0079] Inner ring 53 is secured by bolt B3 ( Figure 11 The inner ring 53 is fixed to the surface of the second retainer portion 42 opposite to the column portion 43, and engages with the outer ring of the second support bearing 15 from the radial side D2. The inner ring 53, together with the inner circumferential pin retainer 40, forms the output shaft and is mounted on the mating member (not shown).

[0080] The rolling elements 52 are cylindrical rollers, and the rotation axes of adjacent cylindrical rollers in the circumferential direction are orthogonal to each other. The outer ring 51 and inner ring 53 are made of metal materials such as JIS high-carbon chromium bearing steel, but are not limited to these. In addition, the main bearing 50 may also include a cage or a spacer.

[0081] Next, the operation of the reducer 1 in the first embodiment will be explained.

[0082] First, when the motor (not shown) drives the input shaft 10, the input shaft 10 rotates at high speed. Simultaneously, the centers of the first external gear 20 and the second external gear 21 rotate (revolve) around the center of the input shaft 10. Furthermore, for each revolution of the input shaft 10, the external teeth 27 of the first and second external gears 20 (…)… Figure 8 The first external gear 20 and the second external gear 21 successively contact the circumferentially adjacent outer peripheral pins 31. As a result, the first external gear 20 and the second external gear 21 revolve at high speed and rotate at low speed inside the radial direction D2 of the outer peripheral pin cage 30.

[0083] As a result, the outer ring 62 of the inner circumferential pin 60, which is internally connected to the elongated holes 26 of the first external gear 20 and the second external gear 21, is pressed circumferentially, causing the inner circumferential pin retainer 40 to rotate at a low speed along with the rotation of the first external gear 20 and the second external gear 21. Consequently, the inner ring 53 mounted on the inner circumferential pin retainer 40 (second retainer portion 42) rotates at a speed lower than that of the input shaft 10. At this time, the direction of rotation of the input shaft 10 is opposite to the direction of rotation of the inner ring 53.

[0084] Next, the effects of the speed reducer 1 in the first embodiment will be explained.

[0085] In the reducer 1, the end face 46 of the column 43 is fixed to the first retainer portion 41 by means of a bolt B1 inserted into the interior of the column 43. Therefore, in the reducer 1, it is not necessary to insert the bolt B1 into the shaft 61 of the inner circumferential pin 60. Therefore, unlike the case where the bolt B1 is inserted into the shaft 61, the inner circumferential pin 60 can be formed more thinly according to the reducer 1. Therefore, the radial dimension of the reducer 1 can be reduced, achieving compactness.

[0086] (Second Implementation)

[0087] Next, according to Figure 15 and Figure 16 The structure of the cycloidal reducer 2 (hereinafter simply referred to as "reducer 2") according to the second embodiment will be described. The reducer 2 of the second embodiment has basically the same structure and achieves the same effect as the reducer 1 of the first embodiment described above, and the main differences are in the number of external gears, etc. Hereinafter, only the differences from the reducer 1 of the first embodiment will be described.

[0088] Figure 15 This is a perspective view showing the external structure of the reducer 2 according to the second embodiment. Figure 16 It is along Figure 15 A cross-sectional view of line segment XVI-XVI in the diagram. (See attached image.) Figure 16 As shown, the reducer 2, in addition to the first external gear 20 and the second external gear 21, also includes a third external gear 82 and a fourth external gear 83. A third eccentric bearing 80 is disposed between the inner circumferential surface of the third external gear 82 and the outer circumferential surface of the input shaft 10 (third shaft portion 19). Furthermore, a fourth eccentric bearing 81 is disposed between the inner circumferential surface of the fourth external gear 83 and the outer circumferential surface of the input shaft 10 (third shaft portion 19). Both the third external gear 82 and the fourth external gear 83 are cycloidal gears, the same as the first external gear 20. Additionally, the third eccentric bearing 80 and the fourth eccentric bearing 81 are, for example, cylindrical roller bearings. Figure 16As shown, the second eccentric bearing 14, the first eccentric bearing 13, the third eccentric bearing 80, the fourth eccentric bearing 81 and the first support bearing 12 are arranged sequentially from the first end 10A toward the second end 10B.

[0089] Compared to the first embodiment described above, in the second embodiment, the input shaft 10 and the inner circumferential pin 60 are longer in the axial direction D1, and the outer circumferential pin retainer 30 and the inner circumferential pin retainer 40 are also thicker in the axial direction D1. Furthermore, as the number of external gears increases, the outer circumferential pin 31 also becomes longer in the axial direction D1, and two outer circumferential pin lubrication members 32 are arranged in the axial direction D1. According to the reducer 2 of the second embodiment, by increasing the number of cycloidal gears, effects such as increased allowable load torque, reduced vibration, and reduced backlash can be achieved. Furthermore, in Figure 15 In this embodiment, a through hole is not formed on the outer peripheral pin retainer 30, but it is not limited to this; a through hole may also be formed in the same way as in the first embodiment described above.

[0090] (Other implementation methods)

[0091] Other implementation methods will be described here.

[0092] In the first embodiment described above, the elongated hole 26 was described as an example of a through hole, but it is not limited to this. For example, the through hole can also be a perfectly round hole.

[0093] Alternatively, the first retainer portion 41 and the column portion 43 can be formed as one piece, and the end face 46 of the column portion 43 can be fixed to the second retainer portion 42 by bolt B1.

[0094] The inner circumferential pin 60 is not limited to being configured in such a way that the post portion 43 is clamped from both sides in the circumferential direction; it is also possible to configure only one inner circumferential pin 60 in the elongated hole 26.

[0095] It should be understood that all embodiments disclosed herein are exemplary and not limited to any particular embodiment. The scope of the present invention is not limited by the foregoing description, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0096] Explanation of reference numerals in the attached figures

[0097] 1, 2 reducers

[0098] 10 input axes

[0099] 10A First End

[0100] 10B Second End

[0101] 11 keys

[0102] 12 First Support Bearing

[0103] 13 First Eccentric Bearing

[0104] 14 Second eccentric bearing

[0105] 15 Second Support Bearing

[0106] 16-speed ring

[0107] 16A incision

[0108] 17 First Shaft

[0109] 18 Second Shaft

[0110] 19 Third Shaft

[0111] 19A keyway

[0112] 20 First external gear

[0113] 20A inner circumferential surface

[0114] 21 Second external gear

[0115] 22 thrust washers

[0116] 23 Pressing Components

[0117] 23A upper surface

[0118] 23B lower surface

[0119] 24 fixing screws

[0120] 25 central hole

[0121] 26 long holes

[0122] 27 external teeth

[0123] 30 outer peripheral pin cage

[0124] 30A Through Hole

[0125] 31 Weekly Sales

[0126] 32 outer peripheral pin lubrication components

[0127] 32A First Pin Retaining Ring

[0128] 33 First pin limiting component

[0129] 33A Second Pin Retaining Ring

[0130] 34 Second pin limiting component

[0131] 35 outer panel

[0132] 40 inner peripheral pin cage

[0133] 40A end face

[0134] 41 First Cage Section

[0135] 41A bolt hole

[0136] 42 Second Cage Section

[0137] 43 column

[0138] 43A internal threaded hole

[0139] 45 holes

[0140] 46 end face

[0141] 50 main bearing

[0142] 51 outer ring

[0143] 52 rolling elements

[0144] 53 Inner Circle

[0145] 54 seals

[0146] Sales within 60 weeks

[0147] 61 axis

[0148] 62 outer ring

[0149] 63 rolling elements

[0150] 64 thrust washers

[0151] 70 Inner Peripheral Pin Lubrication Components

[0152] 71 The third convex part

[0153] 72 first convex part

[0154] 73 second convex part

[0155] 74 Back

[0156] 75 base section

[0157] 80 Third Eccentric Bearing

[0158] 81 Fourth Eccentric Bearing

[0159] 82 Third External Gear

[0160] 83 Fourth External Gear

[0161] B1, B2, B3 bolts

[0162] D2 radial

Claims

1. A speed reducer, wherein, have: An external gear is ring-shaped and has multiple external teeth arranged circumferentially on its outer circumferential surface, and multiple through holes arranged axially along the circumferential direction. An input shaft passes through the space surrounded by the inner circumferential surface of the external gear and extends along the axial direction; A bearing, disposed between the external gear and the input shaft, holds the input shaft so that it can rotate relative to the external gear in the circumferential direction. An internal gear, in the shape of a ring, has a plurality of internal teeth arranged along the circumferential direction on the inner circumferential surface and meshing with the external teeth, and surrounds the outer circumferential surface of the external gear; Multiple inner peripheral pins, passing through multiple through holes along the axial direction; as well as An inner circumferential pin retainer holds both ends of the inner circumferential pin, forming a space through which the input shaft passes. The inner circumferential pin retainer includes: The first retainer portion has an annular retaining portion for retaining the first end of the inner circumferential pin; The second retainer portion has an annular retaining portion for retaining the second end of the inner circumferential pin on the side opposite to the first end; and The column portion connects the first retainer portion and the second retainer portion, and is arranged at intervals along the circumferential direction, and extends through the through hole. The reducer also features: A fixing member is inserted into the interior of the column from its end face, fixing the end face of the column to either the first retainer or the second retainer. The cross-sectional shape of the column portion perpendicular to its length direction is an arc extending along the circumferential direction. The plurality of through holes are elongated holes extending along the circumferential direction. Each of the plurality of through holes is inserted with a post and a pair of inner circumferential pins that clamp the post in the circumferential direction.

2. The reducer as described in claim 1, wherein, The plurality of through holes are elongated holes extending in a circular arc shape along the circumference.

3. The reducer as described in claim 1 or 2, wherein, The inner circumferential pin is a rolling bearing or a sliding bearing.

4. The reducer as described in claim 1 or 2, wherein, It also includes: a lubrication component disposed inside the through hole and in contact with the inner peripheral pin. A groove for accommodating the lubrication component is formed in the column portion. The shape of the cross-section of the groove perpendicular to its length corresponds to that of the lubrication component.

5. The reducer as described in claim 4, wherein, The lubrication component, in a cross-section formed by cutting with a plane perpendicular to the axial direction, includes: The base portion extends radially; The first protrusion protrudes from the first end of the base portion; The second protrusion protrudes from the second end of the base portion on the side opposite to the first end; and The third protrusion protrudes from between the first end and the second end of the base portion. The lubrication component is oscillating to achieve a first contact state and a second contact state. The first contact state is when the first protrusion and the third protrusion are in contact with the inner circumferential pin and the second protrusion is separated from the inner circumferential pin. The second contact state is when the second protrusion and the third protrusion are in contact with the inner circumferential pin and the first protrusion is separated from the inner circumferential pin.

Images