Cycloid reduction gear

Abstract

To achieve a cycloid reduction gear which can improve transmission efficiency to higher efficiency as compared with conventional ones.SOLUTION: A cycloid reduction gear (100) includes: an input shaft (130) having an eccentric portion (132); a plurality of rolling pins (170) having shaft sections (171a) which are arranged at equal intervals in a circumferential direction outside the input shaft (130) and rotate by being driven by eccentric oscillation rotation of the eccentric portion (132) of the input shaft (130) and shaft end sections (171e, 171f) eccentric to the shaft sections (171a); an internal gear (180) having an internal tooth of a wave type tooth form (182a) composed of an epitrochoid parallel curved line which performs rolling contact with the plurality of rolling pins (170); and output carriers (160, 190) which have holding sections (162a, 193a) which rotatably hold the shaft end sections (171e, 171f) in the plurality of rolling pins (170) and are arranged coaxially with the input shaft (130).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a cycloidal reducer. [Background technology]

[0002] Conventionally, typical non-backlash reducers include wave reducers that use the differential between an ellipse and a perfect circle, and cycloid reducers that consist of an internal planetary gear mechanism. Wave reducers (such as those manufactured by Harmonic Drive Systems, Inc.) can achieve low backlash by using elastic internal teeth.

[0003] However, wave reducers are structurally unable to achieve a low reduction ratio, and problems have been raised such as the hollow cylindrical portion bending as it rotates and then gradually returning to a circular shape, which makes it longer in the axial direction, a decrease in transmission efficiency due to elastic bending of the hollow cylindrical portion, and a decrease in strength of the hollow cylindrical portion.On the other hand, cycloid reducers can achieve a high reduction ratio by using a cycloid gear with teeth that are parallel to a trochoid curve (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-55343 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the cycloid reducer of Patent Document 1, although the structural strength is high, the transmission efficiency is reduced due to the large number of sliding parts, and the number of irregular parts increases due to the presence of the Oldham mechanism for extracting output torque without eccentricity, so the structure is complex and the transmission efficiency is insufficient.

[0006] An example of an object of the present invention is to realize a cycloid reducer that can achieve higher transmission efficiency than conventional ones. [Means for solving the problem]

[0007] The cycloidal reducer of the present invention comprises an input shaft having an eccentric portion, a shaft portion arranged at equal intervals in the circumferential direction on the outside of the input shaft and rotating in response to the eccentric oscillating rotation of the eccentric portion of the input shaft, a plurality of rolling pins having eccentric shaft ends with respect to the shaft portion, an internal gear having internal teeth with a wave-shaped tooth profile consisting of epitrochoidal parallel curves that are in rolling contact with the plurality of rolling pins, and an output carrier arranged coaxially with the input shaft and having holding portions that rotatably hold the shaft ends of the plurality of rolling pins. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an overall configuration of a cycloidal reducer according to an embodiment that is an example of the present invention. [Diagram 2] 1 is a cross-sectional view showing an internal structure of a cycloid reducer according to an embodiment that is an example of the present invention. [Diagram 3] 1 is a perspective view showing a configuration of an input shaft side housing of a cycloid reducer according to an embodiment which is an example of the present invention. FIG. [Figure 4] FIG. 2 is a perspective view showing a configuration of an input shaft side rolling pin support plate of a cycloid reducer according to an embodiment which is an example of the present invention. [Diagram 5] 1 is a perspective view showing a configuration of an output shaft side housing of a cycloidal reducer according to an embodiment which is an example of the present invention. FIG. [Figure 6] FIG. 2 is a perspective view showing a configuration of an output shaft side rolling pin support plate of a cycloid reducer according to an embodiment which is an example of the present invention. [Figure 7] FIG. 1 is a perspective view showing a configuration of an input shaft of a cycloid reducer according to an embodiment which is an example of the present invention. [Figure 8]1A is a perspective view showing the overall configuration of a rolling pin of a cycloid reducer according to an embodiment which is one example of the present invention; FIG. 1B is a top view showing the overall configuration of the rolling pin; FIG. 1C is a perspective view showing the configuration of a shaft portion; and FIG. 1D is a front view showing the configuration of the shaft portion. [Figure 9] 1A and 1B are a perspective view and a plan view showing a configuration of an internal gear of a cycloidal reducer according to an embodiment that is an example of the present invention. [Figure 10] 1 is a cross-sectional view illustrating an operation of a cycloid reducer according to an embodiment that is an example of the present invention. FIG. [Figure 11] 3A and 3B are schematic diagrams showing trajectories of rolling pins (shaft portion and bearings) of a cycloid reducer according to an embodiment that is an example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing the overall configuration of a cycloid reducer according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing the internal structure of a cycloid reducer according to an embodiment of the present invention. Fig. 3 is a perspective view showing the configuration of an input shaft side housing of a cycloid reducer according to an embodiment of the present invention.

[0010] Fig. 4 is a perspective view showing the configuration of an input shaft side rolling pin support plate of a cycloid reducer according to an embodiment which is one example of the present invention. Fig. 5 is a perspective view showing the configuration of an output shaft side housing of a cycloid reducer according to an embodiment which is one example of the present invention. Fig. 6 is a perspective view showing the configuration of an output shaft side rolling pin support plate of a cycloid reducer according to an embodiment which is one example of the present invention.

[0011] Fig. 7 is a perspective view showing the configuration of an input shaft of a cycloid reducer according to an embodiment which is one example of the present invention. Fig. 8 is a perspective view (A) showing the overall configuration of a rolling pin of a cycloid reducer according to an embodiment which is one example of the present invention, a top view (B) showing the overall configuration of the rolling pin, a perspective view (C) showing the configuration of a shaft portion, and a front view (D) showing the configuration of the shaft portion.

[0012] Fig. 9 is a perspective view (A) and a plan view (B) showing the configuration of an internal gear of a cycloid reducer according to an embodiment of the present invention. Fig. 10 is a cross-sectional view for explaining the operation of a cycloid reducer according to an embodiment of the present invention. Fig. 11 is a schematic diagram (A) and (B) showing the trajectory of a rolling pin (shaft part and bearing) of a cycloid reducer according to an embodiment of the present invention.

[0013] For the sake of convenience, in the description of the embodiments of the present invention, the direction of arrow a is referred to as the upper side or one side, and the direction of arrow b is referred to as the lower side or the other side. Here, the direction of arrow ab is referred to as the up-down direction or vertical direction. The direction of arrow cd is referred to as the left-right direction, and when the output shaft side of the cycloid reducer is viewed from the front side, the direction of arrow c is referred to as the left side, and the direction of arrow d is referred to as the right side. Furthermore, the direction of arrow e is referred to as the input shaft side, the direction of arrow f is referred to as the output shaft side, and the direction of arrow ef is referred to as the axial X direction or depth direction.

[0014] <Cycloid reducer> As shown in Figures 1 and 2, a cycloidal reducer 100 of the present invention is a reducer that reduces the power from a drive source (not shown) at a predetermined reduction ratio and outputs it, and is used, for example, in electric vehicles, hybrid vehicles, robots, industrial machines, etc.

[0015] As shown in Figures 1 and 2, the cycloidal reducer 100 mainly comprises an input shaft side housing 110, an output shaft side housing 120, an input shaft 130, a shaft support plate 140, an output shaft 150, an input shaft side rolling pin support plate 160 (Figure 2), rolling pins 170 (Figure 2), an internal gear 180, and an output shaft side rolling pin support plate 190 (Figure 2).

[0016] Here, FIG. 1 shows the cycloidal reducer 100 in a state where all parts are assembled, whereas FIG. 2 shows the cycloidal reducer 100 shown in FIG. 1 in a state where the shaft support plate 140 and the output shaft 150 have been removed.

[0017] <Input shaft side housing> As shown in FIG. 3, the input shaft side housing 110 of the cycloid reducer 100 has a square-shaped angular cylinder portion 111 (hereinafter referred to as the "input shaft side angular cylinder portion") that is short in the direction of axis X and is provided on the input shaft side (direction of arrow e) in a plan view, and a angular cylinder portion 112 (hereinafter referred to as the "output shaft side angular cylinder portion") that is short in the direction of axis X and is provided on the output shaft side (direction of arrow f) of the input shaft side angular cylinder portion 111.

[0018] The input shaft side angular cylinder portion 111 of the input shaft side housing 110 has through holes 111a at its four corners for connecting to the shaft support plate 140 with bolts B1 (FIG. 1). The input shaft side angular cylinder portion 111 also has a through hole 111h at its center for accommodating a protruding portion (not shown) of the shaft support plate 140 that protrudes toward the output shaft side (in the direction of arrow f).

[0019] The output-shaft-side angular tube portion 112 of the input-shaft-side housing 110 has cutout portions 112k cut into quadrant shapes at its four corners, and has two through holes 112a on each side of the cutout portions 112k. Therefore, the output-shaft-side angular tube portion 112 has a total of eight through holes 112a, and the through holes 112a also penetrate the input-shaft-side angular tube portion 111.

[0020] That is, the input shaft side housing 110 has eight through holes 112a penetrating the input shaft side angular cylindrical portion 111 and the output shaft side angular cylindrical portion 112. The eight through holes 112a in the input shaft side housing 110 are used for connecting the internal gear 180 and the output shaft side housing 120 with bolts (not shown) or the like.

[0021] Furthermore, the output-shaft side angular cylinder portion 112 has, in its center, a through-hole 112h for holding a cylindrical portion 161 and a flange portion 162 of an input-shaft side rolling pin support plate 160 (FIGS. 2 and 4) which will be described later.

[0022] Therefore, the input shaft side housing 110 has a space in the through hole 112h of the output shaft side square cylinder portion 112, so that it is possible to hold the cylindrical portion 161 and the flange portion 162 of the input shaft side rolling pin support plate 160.

[0023] In practice, the output-shaft-side square cylinder portion 112 of the input-shaft-side housing 110 can rotatably support the cylindrical portion 161 of the input-shaft-side rolling pin support plate 160 via a bearing 115 (FIG. 2). As the bearing 115, for example, a ball bearing or a roller bearing can be used.

[0024] <Input shaft side rolling pin support plate> As shown in Figures 2 and 4, the input shaft side rolling pin support plate 160 is rotatably supported by bearing 115 relative to the input shaft side housing 110, and has a structure in which a cylindrical portion 161 on the input shaft side (direction of arrow e) and a flange portion 162 on the output shaft side (direction of arrow f) are integrated.

[0025] A through hole 161h is formed in the center of the cylindrical portion 161 of the input shaft side rolling pin support plate 160. Also, a through hole 162h is formed in the center of the flange portion 162 of the input shaft side rolling pin support plate 160.

[0026] The inner diameter of the through hole 162h of the flange portion 162 is larger than the inner diameter of the through hole 161h of the cylindrical portion 161. Moreover, the distance in the axial direction of the through hole 162h of the flange portion 162 (the direction of the arrow ef) is longer than the distance in the axial direction of the through hole 161h of the cylindrical portion 161. The input shaft side rolling pin support plate 160 has a step portion 163 between the through hole 161h of the cylindrical portion 161 and the through hole 162h of the flange portion 162.

[0027] The through hole 161h of the cylindrical portion 161 is a portion that holds an input shaft side bearing (hereinafter referred to as the "input shaft side bearing") 165 (Figure 1) that supports the shaft portion on the input shaft side (in the direction of arrow e) of the eccentric portion 132 provided on the input shaft 130.

[0028] When the cylindrical portion 161 holds the input shaft side bearing 165, the stepped portion 163 prevents the input shaft side bearing 165 from slipping out toward the input shaft side (in the direction of the arrow e). As the input shaft side bearing 165, for example, a ball bearing or a roller bearing can be used.

[0029] A flat surface 162f on the output shaft side (arrow f direction) of the flange portion 162 perpendicular to the axial direction X of the flange portion 162 is formed with twelve recesses (hereinafter referred to as "rolling pin support recesses") 162a evenly spaced around the circumference.

[0030] These twelve rolling pin support recesses 162a serving as retaining portions are cylindrical recesses with a circular bottom in a plan view, and support an input shaft side bearing 172e provided on the input shaft side (direction of arrow e) of the rolling pin 170 described below. In this case, the outer ring of the input shaft side bearing 172e is fixed to the rolling pin support recesses 162a of the flange portion 162 by press fitting or the like.

[0031] <Output shaft side housing> As shown in FIGS. 5(A) and 5(B), the output shaft side housing 120 of the cycloid reducer 100 has a main body 121 which is a square prism body short in the direction of axis X when viewed from above, and a cylindrical portion 122 which is short in the direction of axis X and is provided on the output shaft side (direction of arrow f) of the main body 121.

[0032] The main body 121 of the output shaft side housing 120 has four through holes 121a at its four corners for coupling with other devices or equipment. The main body 121 also has a through hole 121h for holding the output shaft side rolling pin support plate 190. This through hole 121h of the main body 121 extends beyond the main body 121 to near the center of the cylindrical portion 122.

[0033] The main body 121 of the output shaft side housing 120 has bottomed cylindrical recesses 121r on both sides of the four through holes 121a around the through holes 121h on the flat surface 121t on the input shaft side (arrow e direction). In other words, a total of eight recesses 121r are formed on the flat surface 121t of the main body 121, and a female screw portion is formed on the inner peripheral surface.

[0034] The cylindrical portion 122 of the output shaft side housing 120 has a through hole 122h for holding the oil seal 198 (FIG. 1). The cylindrical portion 122 has an annular protruding portion 123 that forms a boundary between the through hole 122h for holding the oil seal 198 and the through hole 121h of the main body portion 121.

[0035] The length in the axial direction of the through hole 122h in the cylindrical portion 122 is the same as the width of the oil seal 198, but is shorter than the length in the axial direction of the through hole 121h in the main body portion 121. The protruding portion 123 provided between the through hole 121h in the main body portion 121 and the through hole 122h in the cylindrical portion 122 is an annular projection that protrudes slightly inward from the inner circumferential surface of the cylindrical portion 122, and forms the boundary between the through hole 121h and the through hole 122h.

[0036] <Output shaft side rolling pin support plate> As shown in Figures 2 and 6(A) and (B), the output shaft side rolling pin support plate 190 used as an output carrier is rotatably supported by the output shaft side housing 120, and has a central cylindrical portion 191, a small diameter cylindrical portion 192 on the output shaft side (arrow f direction), and a flange portion 193 on the input shaft side (arrow e direction).

[0037] The cylindrical body portion 191 of the output shaft side rolling pin support plate 190 is a member consisting of a cylindrical body extending in the axial X direction (arrow ef direction), and has a small diameter cylindrical body portion 192 integrated with it on the output shaft side (arrow f direction) and a flange portion 193 integrated with it on the input shaft side (arrow e direction).

[0038] A bearing 125 that supports the rotation of the output shaft side rolling pin support plate 190 is attached between the outer circumferential surface of the cylindrical body portion 191 and the inner circumferential surface that forms the through hole 121h of the main body portion 121 in the output shaft side housing 120. Note that as the bearing 125, for example, a ball bearing or a roller bearing can be used.

[0039] The small diameter cylindrical portion 192 of the output shaft side rolling pin support plate 190 is a cylindrical member having a smaller diameter than the cylindrical portion 191, and has a cylindrical recess 192r with a bottom in the center. The recess 192r of the small diameter cylindrical portion 192 is a portion into which a cylindrical portion (not shown) provided on the input shaft side (direction of arrow e) of the base 151 of the output shaft 150 used as an output carrier is press-fitted.

[0040] The small diameter cylindrical portion 192 of the output shaft side rolling pin support plate 190 has a plurality of (six) mounting holes 192a arranged at equal intervals around the circumferential direction outside the recess 192r. Female threads are formed on the inner peripheral surfaces of these six mounting holes 192a.

[0041] The six mounting holes 192a in the small diameter cylindrical portion 192 correspond to six bolts B2 attached to the base 151 of the output shaft 150 (FIG. 1). Therefore, the output shaft side rolling pin support plate 190 and the base 151 of the output shaft 150 are fixed together by the six mounting holes 192a in the small diameter cylindrical portion 192 and the six bolts B2.

[0042] The flange portion 193 of the output shaft side rolling pin support plate 190 is a flange-shaped member having a larger diameter than the cylindrical portion 191, and has a bottomed recess 193r that is circular in plan view and formed from the input shaft side (direction of arrow e) toward the output shaft side (direction of arrow f).

[0043] The inner diameter of the recess 193r of the flange portion 193 is larger than the inner diameter of the recess 192r of the small diameter cylindrical body portion 192. Moreover, the recess 193r of the flange portion 193 reaches from the flange portion 193 to the cylindrical body portion 191. However, the recess 193r of the flange portion 193 and the recess 192r of the small diameter cylindrical body portion 192 do not communicate with each other (see FIG. 2).

[0044] 2, recess 193r of flange portion 193 is a portion that holds output-shaft-side bearing 195 that axially supports a shaft portion of input shaft 130 on the output-shaft side (in the direction of arrow f), and the axial depth of recess 193r is approximately the same as the width of bearing 195. As bearing 195, for example, a ball bearing or a roller bearing can be used.

[0045] In a flat annular end face 193t on the input shaft side (direction of arrow e) of the flange portion 193, twelve rolling pin supporting recesses 193a serving as retaining portions are formed around the recess 193r and evenly spaced in the circumferential direction.

[0046] These rolling pin support recesses 193a are cylindrical recesses with a bottom that are circular in plan view, and support an output shaft side bearing 172f provided on the output shaft side (direction of arrow f) of the rolling pin 170 described later. In this case, the outer ring of the output shaft side bearing 172f is fixed to the rolling pin support recesses 193a of the flange portion 193 by press fitting or the like.

[0047] As shown in FIG. 2, the twelve rolling pin support recesses 193a provided on the flange portion 193 of the output shaft side rolling pin support plate 190 and the rolling pin support recesses 162a of the input shaft side rolling pin support plate 160 described above are arranged to face each other in the cycloid reducer 100.

[0048] <Input shaft> As shown in FIG. 7, the input shaft 130 is a cylindrical member extending along the axis X direction (arrow ef direction) and has a shaft main body 131 consisting of a cylindrical body centered on the axis X, and an eccentric portion 132 which is a part of the input shaft side (arrow f direction) of the shaft main body 131 and is integrally provided eccentrically a predetermined distance from the axis X of the shaft main body 131.

[0049] 2, the shaft main body 131 of the input shaft 130 is rotatably supported by an input shaft side bearing 165 held by an input shaft side rolling pin support plate 160 of the input shaft side housing 110, and a bearing 195 held by an output shaft side rolling pin support plate 190 of the output shaft side housing 120. The axis (axis X) of the shaft main body 131 coincides with the axis (axis X) of the shaft 152 of the output shaft 150 (FIG. 1).

[0050] The eccentric portion 132, which is integral with the input shaft 130, has a thick portion and a thin portion relative to the outer peripheral surface of the shaft main body 131, and the axis of the shaft main body 131 (axis X) and the axis of the eccentric portion 132 do not coincide with each other, and the eccentric portion 132 is eccentric with respect to the shaft main body 131.

[0051] Moreover, the eccentric portion 132 of the input shaft 130 is rotatably supported by a bearing 185 held on the inner peripheral surface of a cylindrical spacer 187 provided inside an internal gear 180, which will be described later. Note that, in this case as well, the bearing 185 may be, for example, a ball bearing or a roller bearing.

[0052] Specifically, the eccentric portion 132 of the input shaft 130 is fixed to an inner ring of a bearing 185, and an outer ring of the bearing 185 is fixed to an inner peripheral surface of a spacer 187. Note that a rolling pin 170 is disposed between the internal gear 180 and the spacer 187.

[0053] <Rolling pin> As shown in Figures 8(A) to (D), the rolling pin 170 has a pin main body 171, an input shaft side bearing 172e attached to the end of the pin main body 171 on the input shaft side (in the direction of arrow e), and an output shaft side bearing 172f attached to the end of the pin main body 171 on the output shaft side (in the direction of arrow f).

[0054] In this case, a total of 12 rolling pins 170 are provided, which is the same number as the number of rolling pin support recesses 162a of the input shaft side rolling pin support plate 160 and the number of rolling pin support recesses 193a of the output shaft side rolling pin support plate 190.

[0055] The pin main body 171 of the rolling pin 170 has a central shaft portion 171a, a shaft end portion 171e (hereinafter referred to as the "input shaft side shaft end portion") that is fixed integrally to the end portion on the input shaft side (direction of arrow e) of the shaft portion 171a, and a shaft end portion 171f (hereinafter referred to as the "output shaft side shaft end portion") that is fixed integrally to the end portion on the output shaft side (direction of arrow f).

[0056] The shaft portion 171a of the pin main body 171 is a cylindrical body having a predetermined length in the axial direction (the direction of the arrow ef), and is formed to be slightly longer than the width in the axial direction of the internal gear 180. The shaft portion 171a is in contact with the outer peripheral surface of a spacer 187 on the outside of the input shaft 130, and is a portion that eccentrically oscillates in response to the eccentric oscillating rotation of the spacer 187 caused by the eccentric portion 132 of the input shaft 130.

[0057] The shaft portion 171a rolls and rotates while contacting the outer peripheral surface of the spacer 187, and also rolls and rotates while contacting a wave-shaped tooth profile 182a formed on the inner peripheral surface of a curved plate 182 in the internal gear 180 described later.

[0058] The input shaft side end 171e and the output shaft side end 171f of the pin body 171 have a smaller diameter than the shaft portion 171a. The central axis C2 of the input shaft side end 171e and the output shaft side end 171f does not coincide with the central axis C1 of the shaft portion 171a.

[0059] That is, in the pin body 171, the input shaft end 171e and the output shaft end 171f are disposed at positions on a central axis C2 that is eccentric a predetermined distance from the central axis C1 of the shaft portion 171a. The central axes C2 of the input shaft end 171e and the output shaft end 171f are aligned.

[0060] In this manner, the input shaft side shaft end 171e and the output shaft side shaft end 171f are eccentric with respect to the shaft portion 171a. An input shaft side bearing 172e and an output shaft side bearing 172f are fixed to the input shaft side shaft end 171e and the output shaft side shaft end 171f, respectively. As the input shaft side bearing 172e and the output shaft side bearing 172f, for example, a ball bearing or a roller bearing can be used.

[0061] The input shaft side bearing 172e of the rolling pin 170 is attached to the rolling pin support recess 162a of the input shaft side rolling pin support plate 160. In this case, the outer ring of the input shaft side bearing 172e is fixed to the rolling pin support recess 162a, and the inner ring of the input shaft side bearing 172e is fixed to the input shaft side shaft end portion 171e of the pin main body portion 171.

[0062] The output shaft side bearing 172f of the rolling pin 170 is attached to the rolling pin support recess 193a of the output shaft side rolling pin support plate 190. In this case, the outer ring of the output shaft side bearing 172f is fixed to the rolling pin support recess 193a, and the inner ring of the output shaft side bearing 172f is fixed to the output shaft side shaft end portion 171f of the pin main body portion 171.

[0063] In this way, the input shaft side bearing 172e of the rolling pin 170 is supported by the input shaft side rolling pin support plate 160, and the output shaft side bearing 172f is supported by the output shaft side rolling pin support plate 190. Therefore, the rolling pin 170 is held in a stable state by being supported at two points by the input shaft side rolling pin support plate 160 and the output shaft side rolling pin support plate 190.

[0064] <Internal gear> As shown in Figures 9(A) and (B), the internal gear 180 has an approximately square shape when viewed from above, and is a plate-like member that is fixed together while being sandwiched between the input shaft side housing 110 and the output shaft side housing 120, and has a main body portion 181 and a curved plate 182.

[0065] The main body 181 of the internal gear 180 has cutouts 181k cut into quadrant shapes at its four corners, and has two through holes 181a on each side of the cutout 181k. In other words, the main body 181 has a total of eight through holes 181a at its four corners.

[0066] These eight through holes 181a are provided at positions corresponding to the eight through holes 111a of the output-shaft side angular tube portion 112 of the input-shaft side housing 110 and the eight recesses 121r of the main body portion 121 of the output-shaft side housing 120.

[0067] That is, the eight through holes 181a in the main body 181 and the eight through holes 111a in the output-shaft side square tube portion 112 of the input-shaft side housing 110 are aligned with each other, and bolts (not shown) are inserted therethrough.

[0068] In this state, the eight through holes 181a in the main body 181 are aligned with the eight recesses 121r in the main body 121 in the output shaft side housing 120, and the bolts are screwed into the female threads of the eight recesses 121r, thereby connecting the three components together as a single unit.

[0069] Moreover, the curved plate 182 of the internal gear 180 is an annular member formed integrally inside the main body 181, and a wave-shaped tooth profile 182a is formed on its inner peripheral surface. The wave-shaped tooth profile 182a of the curved plate 182 is a wave shape consisting of convex portions and concave portions, and the convex portions form internal teeth.

[0070] The wave-type tooth profile 182a of the curved plate 182 is made up of a trochoid parallel curve corresponding to the eccentric oscillating rotation of the shaft portion 171a of the rolling pin 170 which is driven by the spacer 187, and in this case has a total of 25 internal teeth.

[0071] The protrusions and recesses of the wave-shaped tooth profile 182a come into contact with the shaft portion 171a of the rolling pin 170, and are the portions along which the shaft portion 171a rolls and rotates. Therefore, the shaft portion 171a of the rolling pin 170 can roll and rotate smoothly relative to the wave-shaped tooth profile 182a of the curved plate 182 without slipping.

[0072] The internal gear 180 configured in this manner is immovable because it is integrated and sandwiched between the input shaft side housing 110 and the output shaft side housing 120, as shown in Figure 2, and the curved plate 182 of the internal gear 180 sandwiches the shaft portion 171a of the rolling pin 170 between itself and the spacer 187 in the radial direction, as shown in Figure 10.

[0073] In addition, the input shaft side rolling pin support plate 160 provided on the input shaft side (arrow e direction) of the internal gear 180, and the output shaft side rolling pin support plate 190 provided on the output shaft side (arrow f direction) of the internal gear 180 are not in contact with the internal gear 180 in the axial X direction (arrow ef direction) and can rotate relative to the internal gear 180.

[0074] <Operation of the cycloid reducer> In the cycloid reducer 100, as shown in FIG. 10, when the input shaft 130 is rotated, for example, counterclockwise by a drive source (not shown), the eccentric portion 132 of the input shaft 130 also eccentrically oscillates in the counterclockwise direction.

[0075] At this time, the inner ring 185i of the bearing 185 fixed integrally with the eccentric portion 132 also rotates counterclockwise, but the rolling elements (balls) 185b of the bearing 185 rotate clockwise, and the outer ring 185g of the bearing 185 also rotates clockwise. As a result, the spacer 187 fixed integrally with the outer ring 185g of the bearing 185 rotates clockwise together with the outer ring 185g (eccentric oscillating rotation).

[0076] The spacer 187 eccentrically oscillates in a clockwise direction opposite to the eccentric oscillating rotation of the eccentric portion 132 of the input shaft 130 in the counterclockwise direction, and the shaft portion 171a of the rolling pin 170, which is in contact with the outer peripheral surface of the spacer 187, is also rotated in conjunction with the spacer 187, and therefore eccentrically oscillates (rotates on its own axis) in the counterclockwise direction opposite to that of the spacer 187.

[0077] At this time, since the wave-shaped tooth profile 182a of the curved plate 182 in the internal gear 180 is formed by a trochoidal parallel curve that can follow the eccentric oscillating rotation of the rolling pin 170, the shaft portion 171a of the rolling pin 170 rotates in the counterclockwise direction while rolling along the wave-shaped tooth profile 182a without slipping.

[0078] In this manner, the shaft portion 171a of the rolling pin 170 rotates in the counterclockwise direction while eccentrically oscillating along the wave tooth profile 182a as shown in FIG. 11(A), while the input shaft side bearing 172e and the output shaft side bearing 172f, which are attached at an eccentric position relative to the shaft portion 171a, absorb the eccentric oscillating rotation of the shaft portion 171a and rotate circularly in the clockwise direction as shown in FIG. 11(B).

[0079] That is, since the input shaft side bearing 172e and the output shaft side bearing 172f are attached at an eccentric position relative to the shaft portion 171a, the eccentric rocking rotation of the shaft portion 171a does not affect the rotation of the input shaft side bearing 172e and the output shaft side bearing 172f.

[0080] Therefore, as the shaft portions 171a of the rolling pins 170 each rotate counterclockwise along the wave-shaped tooth profile 182a of the curved plate 182, the twelve rolling pins 170 as a whole revolve (rotate in a circle) in the clockwise direction. Since the twelve rolling pins 170 as a whole rotate in a circle in the clockwise direction, the output shaft side rolling pin support plate 190 that holds the rolling pins 170 also rotates in a circle in the clockwise direction.

[0081] Thus, in the cycloidal reducer 100, the output shaft side rolling pin support plate 190 can be rotated in a circular manner in the clockwise direction via the input shaft side bearing 172e and the output shaft side bearing 172f of the rolling pin 170. As a result, the cycloidal reducer 100 can rotate the output shaft 150 at a predetermined reduction ratio via the output shaft side rolling pin support plate 190.

[0082] In this case, the reduction ratio R1 of the cycloid reducer 100 can be calculated by the following formula (1). R1=-1 / (Zi / Zp-1)=-Zp / (Zi-Zp)……………………(1) Here, Zi = the number of internal teeth (convex portions) that form the wave-shaped tooth profile 182a of the curved plate 182, Zp = the original number of rolling pins 170, and the minus sign means that the output rotates in the opposite direction to the input.

[0083] In fact, in the cycloidal reducer 100, the number of internal teeth (convex portions) of the curved plate 182 of the internal gear 180 is 25, so essentially 24 rolling pins 170 that function as the arc tooth profile that constitutes the internal planetary gear mechanism with a difference in the number of teeth of one are required.

[0084] Therefore, if the curved plate 182 in the internal gear 180 has 25 internal teeth and the orbital motion of all 24 rolling pins 170 is extracted as output from the output shaft side rolling pin support plate 190 and the output shaft 150, the reduction ratio R1 calculated using equation (1) is "24".

[0085] However, the number of rolling pins 170 in this embodiment is half, 12, and the rolling pins 170 are arranged at equal intervals, half the number of rolling pins 170 compared to the case of 24. Even in this case, the reduction ratio R1 is "24", the same as in the case of 24 rolling pins 170.

[0086] The reason for this is that the rolling pins 170 are of an inscribed type that contact the internal teeth (convex portions) of the wave-shaped tooth profile 182a of the curved plate 182, and therefore even if the number of rolling pins 170 is reduced by half, as long as they are evenly in contact with the internal teeth (convex portions) of the curved plate 182, the reduction ratio will not change even if the number of rolling pins 170 is reduced from 24 to, for example, half, 12.

[0087] In the above configuration, the cycloidal reducer 100 can absorb the eccentric oscillating rotation of the shaft portion 171a by the wave-shaped tooth profile 182a of the curved plate 182 in the internal gear 180, and the input shaft side bearing 172e and the output shaft side bearing 172f of the rolling pin 170 which rotates while abutting against the wave-shaped tooth profile 182a.

[0088] As a result, in the cycloid reducer 100, the circular rotation input from the input shaft 130 can be transmitted to the output shaft side rolling pin support plate 190 as a circular rotation output reduced at a predetermined reduction ratio via the input shaft side bearing 172e and the output shaft side bearing 172f of the rolling pin 170.

[0089] In this way, the cycloidal reducer 100 in this embodiment can be simply realized mainly by only the components of the input shaft 130 having the eccentric portion 132, the internal gear 180 having the wave-shaped tooth profile 182a that is a trochoidal parallel curve, the input shaft side bearing 172e that is eccentric with respect to the shaft portion 171a, the rolling pin 170 having the output shaft side bearing 172f, and the output shaft side rolling pin support plate 190.

[0090] In contrast, a conventional cycloid reducer must have an input shaft with an eccentric shaft portion, a curved plate that revolves around the circumference, multiple pin holes provided in the curved plate, an inner pin that rotates while inscribed in the pin hole, and multiple outer pins that engage with the wave-shaped teeth on the outer periphery of the curved plate.

[0091] Therefore, compared to conventional cycloidal reducers, the cycloidal reducer 100 can have a simplified structure, for example by eliminating the need for an Oldham mechanism, and can also reduce the number of irregularly shaped machined parts and the number of parts that require high machining accuracy.

[0092] Furthermore, in the cycloidal reducer 100, the orbital motion of the entire plurality of rolling pins 170 can be transmitted to the output shaft side rolling pin support plate 190 through the rolling rotation of the input shaft side bearing 172e and the output shaft side bearing 172f provided on both side ends of the shaft portion 171a of the rolling pin 170.

[0093] On the other hand, when the inner pin rotates while pressing against the inner peripheral surface of the pin hole of the curved plate as in the conventional cycloid reducer, slippage occurs between the inner peripheral surface of the pin hole and the inner pin. In contrast, in the cycloid reducer 100 of the present embodiment, the rotation of the input shaft 130 can be transmitted to the output shaft side rolling pin support plate 190 by rolling contact without slippage via the input shaft side bearing 172e and the output shaft side bearing 172f of the rolling pin 170, so that the transmission efficiency of the circular rotation output relative to the circular rotation input can be improved and made highly efficient.

[0094] Furthermore, the cycloidal reducer 100 achieves non-backlash through multi-point contact between the multiple rolling pins 170 and the curved plate 182 of the internal gear 180, thereby preventing wear between the wave-shaped teeth 182a of the curved plate 182 and the rolling pins 170 and preventing positioning errors and synchronization errors from occurring even when the input shaft 130 is rotated in reverse.

[0095] Furthermore, in the cycloidal reducer 100, the wave tooth profile 182a of the curved plate 182 in the internal gear 180 has 25 internal teeth (convex portions), and to achieve a reduction ratio of "24", the number of rolling pins 170 should essentially be 24.

[0096] However, in the cycloidal reducer 100, the rolling pins 170 are of an internal type that contact the internal teeth of the curved plate 182 of the internal gear 180, and therefore even if the number of rolling pins 170 is reduced, so long as they are evenly in contact with the internal teeth of the curved plate 182, it is possible to achieve a reduction ratio of "24" even if the number of rolling pins 170 is reduced to half, that is, 12. In fact, the number of rolling pins 170 may be other numbers, such as 18 or 8, so long as they are evenly in contact with the internal teeth of the curved plate 182.

[0097] Therefore, even if there is no space to place the input shaft side bearing 172e and the output shaft side bearing 172f between adjacent rolling pins 170 for an internal gear 180 with 25 internal teeth, it is only necessary to place 12 rolling pins 170, which is half of the 24, so the cycloidal reducer 100 can be made smaller.

[0098] Incidentally, in the cycloidal reducer 100, the reduction ratio can be changed to "12" simply by changing the number of internal teeth (convex portions) of the wave-shaped tooth profile 182a provided on the curved plate 182 of the internal gear 180 to 13 to match the number of rolling pins 170 (12 in this case).

[0099] In other words, in the cycloidal reducer 100, the reduction ratio can be easily changed simply by changing the number of internal teeth of the wave-shaped tooth profile 182a provided on the curved plate 182 of the internal gear 180 in accordance with the number of rolling pins 170, thereby increasing the freedom of design.

[0100] <Other embodiments> Although the cycloidal reducer 100 of the present invention has been described above with reference to a preferred embodiment, the cycloidal reducer 100 of the present invention is not limited to the configuration of the above embodiment.

[0101] For example, in the cycloid reducer 100, the output shaft side rolling pin support plate 190 is used as the output carrier, but the present invention is not limited to this, and the input shaft side rolling pin support plate 160 may be used as the output carrier, or both the output shaft side rolling pin support plate 190 and the input shaft side rolling pin support plate 160 may be used as output carriers.

[0102] In the cycloidal reducer 100 of the present invention, the circular rotation input of the input shaft 130 is transmitted to the output shaft side rolling pin support plate 190 via the output shaft side bearing 172 f of the rolling pin 170 .

[0103] However, the present invention is not limited to this, and it is also possible to insert the output shaft side shaft end 171f of the shaft portion 171a of the rolling pin 170 into the rolling pin support recess 193a of the output shaft side rolling pin support plate 190 without using the output shaft side bearing 172f, and rotate the rolling pin 170 while pressing the inner surface of the rolling pin support recess 193a with the output shaft side shaft end 171f, thereby transmitting the circular rotation input of the input shaft 130 to the output shaft side rolling pin support plate 190.

[0104] In the cycloidal reducer 100 of the present invention, a case has been described in which the reduction ratio is set to "24" when the curved plate 182 of the internal gear 180 has 25 internal teeth and the rolling pins 170 have 12, but the present invention is not limited to this, and the number of internal teeth of the curved plate 182 and the number of rolling pins 170 may be set arbitrarily in accordance with the desired reduction ratio.

[0105] In the cycloidal reducer 100 of the present invention, the number of internal teeth (convex portions) of the wave-shaped tooth profile 182a provided on the curved plate 182 of the internal gear 180 is 25, and the reduction ratio is set to "24" when the number of rolling pins 170 is 12. However, the present invention is not limited to this, and when it is desired to increase the torque of the output shaft 150, the number of rolling pins 170 may be increased.

[0106] In this case, in the cycloidal reducer 100, the torque can be increased while maintaining the same reduction ratio of "24" simply by increasing the number of rolling pins 170. This is because, in the cycloidal reducer 100, the torque of the output shaft 150 depends on the number of rolling pins 170 equipped with the input shaft side bearing 172e and the output shaft side bearing 172f.

[0107] In the cycloidal reducer 100 of the present invention, the rolling pin 170 is disposed between the internal gear 180 and the spacer 187. However, the present invention is not limited to this. Instead of using the spacer 187, a bearing 185 having an outer ring with a diameter including the thickness of the spacer 187 may be used, and the rolling pin 170 may be disposed between the internal gear 180 and the outer ring of the bearing 185.

[0108] In addition, a person skilled in the art can appropriately modify the cycloidal reducer 100 of the present invention and change the combination of various components according to conventionally known knowledge. As long as the configuration of the present invention is still provided even after such modifications, it is of course included in the scope of the present invention. [Explanation of symbols]

[0109] 100...cycloid reducer, 110...input shaft side housing, 111...input shaft side square cylinder portion, 111a...through hole, 111h...through hole, 112...output shaft side square cylinder portion, 112a...through hole, 112h...through hole, 112k...notch portion, 115...bearing, 120...output shaft side housing, 121...main body portion, 121a...through hole, 121h...through hole, 121r...recess, 121t...flat surface, 122... Cylindrical portion, 122h...through hole, 123...projection portion, 125...bearing, 130...input shaft, 131...shaft main body portion, 132...eccentric portion, 140...shaft support plate, 150...output shaft (output carrier), 151...base portion, 152...shaft, 160...input shaft side rolling pin support plate (output carrier), 161...cylindrical portion, 161h...through hole, 162...flange portion, 162a...rolling pin support recess (retaining portion), 162f...flat surface, 162h...through hole, 163...step portion, 165...input shaft side bearing, 170...rolling pin, 171...pin main body portion, 171a...shaft portion, 171e...input shaft side shaft end portion, 171f...output shaft side shaft end portion, 172e...input shaft side bearing, 172f...output shaft side bearing, 180...internal gear, 181...main body portion, 181a...through hole, 181k...notch portion, 182...curved plate, 18 2a...wave tooth profile, 184...internal teeth, 185...bearing, 187...spacer, 190...output shaft side rolling pin support plate (output carrier), 191...cylindrical body portion, 192...small diameter cylindrical body portion, 192a...mounting hole, 192r...recess, 193...flange portion, 193a...rolling pin support recess (retaining portion), 193r...recess, 193t...end surface, 195...bearing, 198...oil seal, B1, B2...bolts.

Claims

1. an input shaft having an eccentric portion; a shaft portion that is arranged in a circumferential direction on the outside of the input shaft and rotates in response to the eccentric swing rotation of the eccentric portion of the input shaft; and a plurality of rolling pins having shaft ends that are eccentric to the shaft portion; an internal gear having internal teeth with a wave-shaped tooth profile that is in rolling contact with the plurality of rolling pins; an output carrier having a holding portion that rotatably holds shaft ends of the plurality of rolling pins and is disposed coaxially with the input shaft; A cycloid reducer comprising:

2. The rolling pins each have a bearing attached to the shaft end, and the bearing is attached to the holding portion, thereby connecting the output carrier. The cycloidal reducer according to claim 1.

3. The number of the rolling pins is less than the number of the internal teeth of the internal gear.

3. A cycloidal reducer according to claim 1 or 2.

4. The rolling pins are disposed at equal intervals in the circumferential direction.

3. A cycloidal reducer according to claim 1 or 2.

5. The wavy tooth profile of the internal gear is composed of epitrochoid parallel curves.

3. A cycloidal reducer according to claim 1 or 2.

6. The plurality of rolling pins are of an internally-contacting type that contacts the internal teeth, and the plurality of rolling pins are evenly in contact with the internal teeth. The cycloidal reducer according to claim 3.

7. a second output carrier that holds an axial end portion of the rolling pin opposite to the axial end portion of the rolling pin and is disposed coaxially with the input shaft; Equipped with The second output carrier has a holding portion that rotatably holds the opposite shaft end portions of the plurality of rolling pins, and is disposed coaxially with the input shaft. The cycloidal reducer according to claim 1.

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