JP2018115715A - Ball speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball speed reducer having a simple structure and having a small number of machining man-hours.SOLUTION: A ball speed reducer 1 includes: an eccentric disk cum 3 turning integrally with an input side rotation body 2; an oscillation body 4 which is engaged with the outer peripheral side of the eccentric disk cum 3 so as to be relatively turnable and is oscillated; a plurality of balls 5 housed in a ball-holding part 23 of the oscillation body 4 so as to be rolled; a fixation member 6 on which a first side surface part 24 facing the one side surface 4a of the oscillation body 4 is formed; and an output side rotation body 7 on which a second side surface part 40 facing the other side surface 4b of the oscillation body 4 is formed. On the first side surface part 24, a plurality of radial-direction grooves 30 guiding the balls 5 along the radial direction are formed. On the second side surface part 40, an annular waveform groove 31 guiding the balls 5 along a circumferential direction in a waveform shape is formed. The waveform groove 31 is such that the groove depth of its peak is deeper than the groove depth at the center position of the wave height. The radial-direction groove 30 is such that the groove depth at a position corresponding to the peak of the waveform groove 31 is shallower than the groove depth at the intermediate position in the radial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ball speed reducer used for decelerating and transmitting rotation.

  Conventionally, the ball speed reducer is smaller and has a larger speed reduction ratio than the gear speed reduction device, so that it can be used as a power transmission unit for various machines (for example, industrial robots, steering angle variable type steering devices, etc.). It is used.

  FIG. 14 is a view showing such a conventional ball speed reducer 100. 14A is a longitudinal sectional view of a conventional ball speed reducer 100, and FIG. 14B is a ball speed reducer 100 cut along line A13-A13 in FIG. 14A. FIG.

  As shown in FIG. 14, in the ball reducer 100, an eccentric rotating plate 104 is attached to the outer peripheral side of an eccentric cam 102 formed on the input shaft 101 via a bearing 103, and the eccentric rotating plate 104 is the eccentric cam 102. Is driven eccentrically. Further, in this ball speed reducer 100, output side rotating bodies 105 connected to an output shaft (not shown) are arranged on both sides on the radially inner side of the eccentric rotating plate 104, and the input shaft 101 is an output side rotating body. It is supported on the inner peripheral side of 105 through a bearing 106 so as to be relatively rotatable. Further, in this ball speed reducer 100, fixing members 107 fixed to a part of an industrial robot or the like are arranged on both sides on the radially outer side of the eccentric rotating plate 104 via balls 108, respectively. A rotating body 105 is rotatably supported on the inner peripheral side of the fixed member 107 via a bearing 110. The ball 108 sandwiched between the eccentric rotating plate 104 and the fixing member 107 is formed by a first corrugated groove (first cycloid groove formed by an outer cycloid curve) 111 formed on the side surface of the eccentric rotating plate 104 and the fixing member 107. The eccentric rotating plate 104 is engaged with a second corrugated groove (second cycloid groove formed by an inner cycloid curve) 112 formed on the inner side surface (side surface facing the eccentric rotating plate 104) so as to roll. And the fixing member 107 are connected. The wave number of the second corrugated groove 112 is formed so as to be two more than the wave number of the first corrugated groove 111.

  Further, the output-side rotator 105 is connected to the eccentric rotating plate 104 via the eccentric absorbing mechanism 113. The eccentric absorbing mechanism 113 allows the eccentric rotating plate 104 to move eccentrically with respect to the output side rotating body 105 (absorbs the eccentricity of the eccentric rotating plate 104). The rotation is transmitted to the output side rotating body 105. The eccentric absorbing mechanism 113 includes a plurality of balls 114 interposed between the eccentric rotating plate 104 and the output-side rotating body 105, and a driving annular groove 115 of the eccentric rotating plate 104 that accommodates the balls 114 in a rollable manner. And a driven annular groove 116 of the output side rotator 105. The shape and size of the driving annular groove 115 and the driven annular groove 116 are determined in consideration of the amount of eccentricity of the eccentric cam 102, and the ball 114 when the eccentric rotating plate 104 rotates eccentrically with respect to the rotation center of the input shaft 101. The output-side rotator 105 can rotate integrally with the eccentric rotating plate 104 via a ball 114 (see Patent Document 1).

  In such a conventional ball speed reducer 100, for example, when the wave number of the first wave groove 111 of the eccentric rotating plate 104 is N-2 and the wave number of the second wave groove 112 of the fixed member 107 is N, the input shaft When 101 is rotationally driven by an electric motor (not shown) or the like, the eccentric rotating plate 104 is eccentrically driven by the eccentric cam 102 of the input shaft 101, and the output side rotating body 105 is integrated with the eccentric rotating plate 104 via the eccentric absorbing mechanism 113. The output-side rotator 105 rotates -2 / (N-2) with respect to one rotation of the input shaft 101 (2 / (N- in the direction opposite to the rotation direction of the input shaft 101). 2) Rotate). That is, in the conventional ball speed reducer 100, when the wave number of the first corrugated groove 111 of the eccentric rotating plate 104 is N-2 and the wave number of the second corrugated groove 112 of the fixed member 107 is N, the reduction ratio is 2 / (N-2).

JP-A-5-10400

  However, in the conventional ball speed reducer 100 shown in FIG. 14, the first corrugated grooves 111 are formed on both side surfaces of the eccentric rotating plate 104, and the inner surfaces of the fixing members 107 respectively disposed on both sides of the eccentric rotating plate 104 are used. Since the second corrugated groove 112 is formed, the corrugated grooves 111, 111, 112, 112 must be formed with high accuracy on a total of four side surfaces (four locations), and the processing man-hours increase. It was.

  Further, since the conventional ball speed reducer 100 shown in FIG. 14 rotates the eccentric rotating plate 104 and the output side rotating body 105 together, the output side rotating body 105 is eccentrically rotated via the eccentric absorbing mechanism 113. The structure is complicated and the processing man-hours increase.

  Accordingly, an object of the present invention is to provide a ball speed reducer that has a simple structure and a small number of processing steps.

  The present invention relates to a ball speed reducer 1 that decelerates and transmits the rotation of an input side rotator 2 to an output side rotator 7. A ball speed reducer 1 according to the present invention is fitted to an eccentric disk cam 3 that rotates integrally with the input-side rotator 2 and to the outer peripheral side of the eccentric disk cam 3 so as to be capable of relative rotation. An oscillating body 4 (55) oscillated by a plate cam 3, a plurality of balls 5 accommodated in a ball holding portion 23 (56) of the oscillating body 4 (55), and both sides of the oscillating body 4 (55) A fixing member 6 having a first side surface portion 24 positioned opposite to one of the surfaces 4a and 4b (55a and 55b) and fixed to the fixed member; The ball holding portion 23 (56) of the rocking body 4 (55) is formed along the relative rotation direction of the rocking body 4 (55) and the eccentric disc cam 3, and the plurality of balls 5 Is accommodated so as to roll along the relative rotation direction. The output-side rotator 7 has a second side surface portion 40 that faces the other of the two side surfaces 4a and 4b (55a and 55b) of the oscillator 4 (55), and serves as a rotation center. Is arranged so as to be coaxial with the rotation center 2a of the input-side rotator 2. Further, any one of the first side surface portion 24 and the second side surface portion 40 has a radial direction extending in a radial direction from the rotation center 2a in a virtual plane orthogonal to the rotation center 2a of the input-side rotator 2. Then, the radial groove 30 that guides the ball 5 so as to roll along the radial direction of one of the first side surface portion 24 and the second side surface portion 40 of the input shaft side rotating body 2. A plurality are formed around the rotation center 2a. Further, the other of the first side surface portion 24 and the second side surface portion 40 has the ball in the virtual plane when the direction along the outer edge of the virtual circle centered on the rotation center 2a is the circumferential direction. An annular corrugated groove 31 (61, 62) is formed to guide 5 in a wave shape along the circumferential direction of the other of the first side surface portion 24 and the second side surface portion 40. The ball 5 is slidably engaged with the radial groove 30 and the corrugated groove 31 (61, 62), and the rocking body 4 (55) is rocked by the eccentric disc cam 3. And roll in the radial groove 30 and the corrugated groove 31 (61, 62). The corrugated groove 31 has a trough 31a at the radially inner end, a peak 31b at the radially outer end, and a wave height central position at an intermediate position between the valley bottom 31a and the peak 31b. The depth is deeper than the groove depth at the center of the wave height, and the groove depth is smoothly changed. The radial groove 30 has a radial position corresponding to the center position of the wave height of the corrugated groove 31 as a radial intermediate position, and a radial position corresponding to the peak 31b of the corrugated groove 31 as a peak corresponding position. Then, the groove depth at the peak-corresponding position is shallower than the groove depth at the radial intermediate position, and the groove depth changes smoothly.

  In the ball speed reducer according to the present invention, the corrugated grooves are formed only on one side surface portion of the output side rotating body and the fixed member facing the oscillating body. Compared to the conventional example, it is possible to reduce the number of processing steps. In the ball speed reducer according to the present invention, since the swinging body can swing independently with respect to the output-side rotating body and the fixed member, the output-side rotating body and the swinging body rotate together. This eliminates the need for a complicated mechanism, and simplifies the structure and reduces the number of processing steps.

  Further, the ball speed reducer 1 according to the present invention makes the groove depth at the peak position of the corrugated groove prone to ratcheting deeper than the other part of the corrugated groove, and the center position of the wave height of the corrugated groove from the peak of the corrugated groove. The height of the ridge formed between adjacent waves (between adjacent peaks and peaks) is increased by decreasing the groove depth toward the top, and the groove is formed by a tool that forms a corrugated groove. Because the gap between the outer edge of the corrugated groove and the ball is reduced and the function of holding the ball by the corrugated groove is strengthened, the ball located in one of the adjacent waves does not easily jump over the ridge line to the other of the adjacent waves (Ratcheting is less likely to occur)

1 is a longitudinal sectional view of a ball speed reducer according to a first embodiment of the present invention. It is a figure which shows the input shaft (input side rotary body) of the ball | bowl speed reducer which concerns on 1st Embodiment of this invention, Fig.2 (a) is the front of the input shaft seen from the direction of arrow B1 of FIG.2 (c). FIG. 2B is a cross-sectional view taken along line A1-A1 in FIG. 2C, and FIG. 2C is a side view of the input shaft. It is a figure which shows the rocking | swiveling body of the ball | bowl speed reducer which concerns on 1st Embodiment of this invention, and Fig.3 (a) is cut | disconnected along the longitudinal cross-sectional view (A2-A2 line of FIG.3 (b)) of a rocking body. 3 (b) is a front view of the oscillating body, FIG. 3 (c) is a longitudinal sectional view of the inner oscillating ring (a cross section taken along the line A3-A3 in FIG. 3 (d)). 3 (d) is a front view of the inner rocking ring, and FIG. 3 (e) is a longitudinal sectional view of the outer rocking ring (a cross-sectional view cut along line A4-A4 in FIG. 3 (f)). ). It is a figure which shows the fixing member of the ball reducer which concerns on 1st Embodiment of this invention, Fig.4 (a) is a front view of a fixing member, FIG.4 (b) is a longitudinal cross-sectional view (Fig.4 (a) of a fixing member. ) Is a sectional view of the fixing member cut along the line A5-A5. It is a figure which shows the output side rotary body of the ball | bowl speed reducer which concerns on 1st Embodiment of this invention, and Fig.5 (a) is a figure which shows the front end surface of an output shaft part (from the direction of arrow B2 of FIG.5 (b)). FIG. 5B is a longitudinal sectional view of the output-side rotating body (a sectional view taken along line A6-A6 in FIG. 5C), FIG. 5C. Is a front view of the output side rotator (view of the output side rotator as seen from the direction of arrow B3 in FIG. 5B), and FIG. 5D is a processing of the boundary (intermediate position) between adjacent waves of the corrugated groove. It is a figure for demonstrating the relationship between the tool diameter to perform and the shape of the outer edge of a waveform groove. It is a figure which shows the cover of the ball reducer which concerns on 1st Embodiment of this invention, Fig.6 (a) is a front view of a cover, FIG.6 (b) follows the A7-A7 line | wire of Fig.6 (a). It is sectional drawing of the cover shown cut | disconnected. It is a figure which shows the modification of the fixing member of the ball | bowl speed reducer which concerns on 1st Embodiment of this invention, Fig.7 (a) is a front view of a fixing member, FIG.7 (b) is a longitudinal cross-sectional view (figure) of a fixing member It is sectional drawing of the fixing member cut | disconnected and shown along the A8-A8 line | wire of 7 (a). It is a figure which shows the modification of the rocking body of the ball | bowl speed reducer which concerns on 1st Embodiment of this invention, and Fig.8 (a) is along the longitudinal cross-sectional view (A9-A9 line of FIG.8 (b)) of a rocking body. FIG. 8B is a front view of the oscillating body, and FIG. 8C is an enlarged view of the ball holding portion of the oscillating body. It is a figure which shows the modification of the waveform groove | channel formed in the output side rotary body of the ball reducer which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the ball reducer which concerns on 2nd Embodiment of this invention. It is a figure which shows the fixing member of the ball reducer which concerns on 2nd Embodiment of this invention, Fig.11 (a) is a front view of a fixing member, FIG.11 (b) is a longitudinal cross-sectional view (Fig.11 (a) of a fixing member. ) Is a sectional view of the fixing member cut along the line A10-A10. It is a figure which shows the output side rotary body of the ball reducer which concerns on 2nd Embodiment of this invention, Fig.12 (a) is a figure which shows the front end surface of an output shaft part (from the direction of arrow B4 of FIG.12 (b)). FIG. 12B is a longitudinal sectional view of the output side rotating body (a sectional view taken along the line A11-A11 in FIG. 12C), and FIG. 12C. These are front views (the figure seen from the direction of arrow B5 of Drawing 12 (b)) of an output side rotating body. It is a figure which shows the modification of the output side rotary body of the ball reducer which concerns on 2nd Embodiment of this invention, Fig.13 (a) is a longitudinal cross-sectional view (A12-A12 of FIG.13 (b)) of an output side rotary body. FIG. 13B is a front view of the output-side rotator as seen from the direction of arrow B6 in FIG. 13A. ). It is a figure which shows the conventional ball reducer, FIG.14 (a) is a longitudinal cross-sectional view of a ball reducer, FIG.14 (b) is sectional drawing cut | disconnected and shown along the A13-A13 line of Fig.14 (a) It is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view of a ball speed reducer 1 according to a first embodiment of the present invention. As shown in FIG. 1, a ball speed reducer 1 according to this embodiment includes an input shaft (input-side rotating body) 2, an eccentric disc cam 3, a rocking body 4, a plurality of balls (steel balls) 5, and a fixing member. 6, an output side rotating body 7, a cover 8, and the like.

  As shown in FIGS. 1 and 2, the input shaft 2 is configured such that the shaft body portion 10 is rotatably supported by a fixing member 6 via a first bearing 11 and is driven to rotate by an electric motor (not shown) or the like. It has become. The input shaft 2 has a hook-shaped portion 12 having a diameter larger than that of the shaft main body portion 10 adjacent to the shaft main body portion 10, and the side surface of the first bearing 11 is abutted against the side surface of the hook-shaped portion 12. The one bearing 11 is held between the inner peripheral projection 14 of the boss portion 13 of the fixing member 6 and the flange portion 12. Further, the input shaft 2 is formed with an eccentric disc cam 3 at a position closer to the shaft tip side than the flange-shaped portion 12 and adjacent to the flange-shaped portion 12. The eccentric disc cam 3 is a disc whose center 3a is eccentric with respect to the rotation center 2a of the input shaft 2 (the rotation center 10a of the shaft body 10) by an eccentric amount (e). And the input shaft 2 are rotated eccentrically around the rotation center 2a. And the rocking body 4 is attached to the outer peripheral side of the eccentric disk cam 3 via the 2nd bearing 15 so that relative rotation is possible. Further, the input shaft 2 has a balance weight attaching portion 16 formed at the outer periphery of the eccentric disc cam 3 and at a position closer to the tip of the shaft than the place where the second bearing 15 is attached. The balance weight mounting portion 16 is formed in a portion (FIG. 2A) formed by cutting out one portion on the outer peripheral side of the eccentric disc cam 3 along a line indicating the center 3a of the eccentric disc cam 3. D-cut shape as shown). A balance weight 17 is press-fitted and fixed to the balance weight mounting portion 16, and a second bearing 15 is held between the balance weight 17 and the hook-shaped portion 12 in a positioned state. Further, the input shaft 2 is formed with a tip shaft portion 20 to which the third bearing 18 is attached. The tip shaft portion 20 has a rotational center concentric with the rotational center 2 a of the shaft main body portion 2, and supports the output side rotating body 7 via a third bearing 18 so as to be rotatable. In the following description, when a virtual plane orthogonal to the rotation center 2a of the input shaft 2 is considered, the radial direction means a direction extending radially from the rotation center 2a on the virtual plane. When a virtual plane orthogonal to the rotation center 2a of the input shaft 2 is considered, the circumferential direction refers to a direction along the outer edge of the virtual circle centered on the rotation center 2a of the input shaft 2.

  As shown in FIGS. 1 and 3, the oscillating body 4 is oscillated by an eccentric disc cam 3, and includes an inner oscillating ring 21 and an outer oscillating ring 22. In the swing body 4, a ball holding portion 23 is formed between the inner swing ring 21 and the outer swing ring 22, and a plurality of balls 5 are accommodated in the ball holding portion 23 in a rollable manner. The ball holding portion 23 of the rocking body 4 has an annular space (the rocking body 4 and the eccentric disk cam 3) formed between the outer peripheral surface 21 a of the inner rocking ring 21 and the inner peripheral surface 22 a of the outer rocking ring 22. The outer rocking ring 22 is supported by a plurality of balls 5 arranged along the circumferential direction of the outer peripheral surface 21a of the inner rocking ring 21 so as to be able to roll. Yes. In addition, the rocking body 4 accommodates a ball support protrusion 25 formed on a first side surface 24 of the fixing member 6 to be described later, and a ball support protrusion relief 26 that enables relative rotation with the fixing member 6. Is formed. The ball support protrusion relief portion 26 includes an inner tapered surface 21b formed so as to be obliquely cut away from the outer peripheral surface 21a of the inner swing ring 21 toward the radially inward side, and the inner periphery of the outer swing ring 22. The outer surface 22a is formed so that the surface 22a is obliquely cut out radially outward, and has a cross-sectional shape that expands toward the first side surface 24 of the fixing member 6. ing. And the 1st side surface part 24 of the fixing member 6 is arrange | positioned so that the one side surface 4a side of the both sides | surfaces 4a and 4b of the rocking | swiveling body 4 may oppose. The inner rocking ring 21 has a plurality of lightening holes 27 formed at equal intervals along the circumferential direction between the bearing surface 21c to which the second bearing 15 is fitted and the outer peripheral surface 21a for supporting the ball 5. Has been.

  As shown in FIGS. 1 and 4, the fixing member 6 is fixed to a fixed member (not shown) (for example, a machine frame or a robot arm), and the shaft main body portion 10 of the input shaft 2 is placed inside the boss portion 13. The first bearing 11 attached to the peripheral surface is rotatably supported. Further, the fixing member 6 is provided on the inner side surface 24a of the first side surface portion 24 facing the one side surface 4a of the oscillating body 4 (side surface facing the one side surface 4a), and the ball support protrusion relief portion 26 of the oscillating body 4. A ball support protrusion 25 is formed to be engaged so as not to come into contact with. The ball support protrusion 25 is a trapezoidal annular body having a tapered cross section, and is an annular body formed concentrically with the center 28 a of the bearing mounting hole 28 of the boss portion 13. The ball support protrusions 25 are formed with a plurality of radial grooves 30 that engage with the balls 5 accommodated in the ball holding portion 23 of the rocking body 4 at equal intervals along the circumferential direction. The radial groove 30 is formed so as to cut out the ball support protrusion 25 in the radial direction, and the cross-sectional shape orthogonal to the radial direction is an arc shape having a curvature radius similar to the radius of the ball 5. The groove depth at the radial intermediate position of the moving trajectory of the ball 5 is the deepest in accordance with the moving trajectory in the radial direction of the rolling ball 5, and the radially outer end of the moving trajectory and the radial inner end of the moving trajectory. The cross-sectional shape has a substantially arc shape from the radially inner side toward the radially outer side so that the groove depth gradually decreases gradually toward the outer surface. Further, the radial groove 30 of the fixing member 6 is formed at (N + 1) locations when the wave number of the waved groove 31 of the output side rotator 7 is N wave, and rolls (N + 1) balls 5 one by one. Accommodate as possible. Such a radial groove 30 of the fixing member 6 is such that when the eccentric disk cam 3 rotates once and the rocking body 4 is swung by one stroke, the ball 5 is divided according to the rocking amount of the rocking body 4. Can only roll in the radial direction. In addition, the fixing member 6 reduces the contact area between the first side surface portion 24 and the rocking body 4 and reduces the contact resistance, so that the first side surface portion 24 and the ball support which are radially inward from the ball support protrusion 25 are used. A plurality of contact relief recesses 32 and 33 are formed along the circumferential direction on the first side surface portion 24 radially outward from the protrusion 25. The fixing member 6 has a cover mounting portion 34 formed on the radially outer end side thereof. And inside this cover attaching part 34, while the rocking | swiveling body 4 is accommodated so that a rocking | swiveling is possible, the output side rotary body 7 is accommodated so that rotation is possible. Further, the cover mounting portion 34 of the fixing member 6 has a substantially rectangular outer shape when viewed from the front side, and includes a positioning pin mounting hole 35, an assembly screw hole 36, and a fixing bolt insertion hole 37 at each corner. It is formed in the part (4 corners). A positioning pin (not shown) that engages with the positioning pin engaging hole 48 of the cover 8 is press-fitted into the positioning pin mounting hole 35. Thereby, the cover 8 is fixed in a state of being positioned on the fixing member 6. In addition, a thread portion (not shown) of an assembly bolt for fixing the cover 8 to the fixing member 6 is screwed into the assembly screw hole 36. In addition, a shaft portion (not shown) of a fixing bolt for integrally attaching the cover 8 and the fixing member 6 to a fixed member (not shown) is inserted into the fixing bolt insertion hole 37. Note that a lubricant such as grease is appropriately accommodated in the contact relief recesses 32 and 33 of the fixing member 6.

  As shown in FIGS. 1 and 5, the output-side rotator 7 includes a second side surface portion 40 that faces the other side surface 4 b of the both side surfaces 4 a and 4 b of the oscillating body 4, and the second side surface. It has a bearing cylindrical portion 41 formed integrally on the radially inner side of the portion 40, and an output shaft portion 42 formed integrally with the bearing cylindrical portion 41. The output-side rotator 7 has an inner peripheral side of the bearing cylindrical portion 41 rotatably supported by the tip shaft portion 20 of the input shaft 2 via the third bearing 18, and an outer peripheral side of the bearing cylindrical portion 41 is The output shaft 42 is concentrically rotated with the rotation center 2 a of the input shaft 2 by being rotatably supported by the cover 8 via a fourth bearing 43. A corrugated groove 31 that engages with the ball 5 accommodated in the ball holding portion 23 of the oscillating body 4 is formed on the inner side surface 40 a of the second side surface portion 40 (side surface facing the other side surface 4 b of the oscillating body 4). The output shaft portion 42 is formed in an annular shape (endless shape) around the rotation center (axial center) 42a. The corrugated groove 31 is configured to guide the ball 5 in a wave shape along the circumferential direction of the second side surface portion 40, with the radially inner end serving as a valley bottom 31a and the radially outer end serving as a peak 31b. If the intermediate position in the radial direction between the valley bottom 31a and the peak 31b is the center of the wave height, the groove depth is such that the groove depth of the valley bottom 31a and the groove depth of the peak 31b are deeper than the groove depth at the center of the wave height. Is changing smoothly. In contrast to the corrugated groove 31 having such a shape, the radial groove 30 has a radial intermediate position corresponding to the center position of the wave height of the corrugated groove 31, and the groove depth at the radial intermediate position is the deepest. The groove depth becomes shallower toward the radial position corresponding to the valley bottom 31a and the radial position corresponding to the peak 31b of the corrugated groove 31. In the output-side rotating body 7, the eccentric disk cam 3 rotates once, the swinging body 4 swings by one stroke, and the ball 5 reciprocates in the radial groove 30 of the fixed member 6 once in the radial direction. Then, the wave groove 31 is rotated by one wave. The output shaft portion 42 is disposed such that the rotation center 42a is concentric with the rotation center of the input shaft 2, and is connected to a driven member (not shown). Further, the output-side rotator 7 reduces the contact area between the second side surface portion 40 and the rocking body 4 to reduce the contact resistance, so that the second side surface portion 40 on the radially inner side from the corrugated groove 31 A plurality of contact relief recesses 44 are formed along the circumferential direction, and a plurality of contact relief recesses 45 are formed along the circumferential direction on the second side surface portion 40 radially outward from the corrugated groove 31. The contact relief recesses 44 and 45 appropriately contain a lubricant such as grease.

  As shown in FIGS. 1 and 6, the cover 8 integrally includes a flange portion 46 and a cylindrical portion 47, and a space for rotatably accommodating the output-side rotator 7 is formed radially inward. Has been. The flange portion 46 has a substantially rectangular shape as viewed from the front side, similar to the outer shape of the cover mounting portion 34 of the fixing member 6, and includes a positioning pin engaging hole 48, an assembly bolt mounting hole 50, and Fixing bolt insertion holes 51 are formed at each corner (four corners). The positioning pin engaging hole 48, the assembly bolt mounting hole 50, and the fixing bolt insertion hole 51 of the cover 8 are in one-to-one correspondence with the positioning pin mounting hole 35, the assembly screw hole 36, and the fixing bolt insertion hole 37 of the fixing member 6. It is formed to correspond. A positioning pin (not shown) fixed to the fixing member 6 is inserted into the positioning pin engaging hole 48. Further, an assembly bolt (not shown) for fastening and fixing the fixing member 6 and the cover 8 is engaged with the assembly bolt mounting hole 50. Further, the fixing bolt insertion hole 51 is engaged with a fixing bolt (not shown) for attaching the cover 8 and the fixing member 6 together to an object to be attached which is not shown. The flange portion 46 of the cover 8 is arranged such that a gap is formed between the side surface 46 a facing the output side rotating body 7 and the second side surface portion 40 of the output side rotating body 7. Further, the cylindrical portion 47 of the cover 8 has an inner peripheral surface of the bearing fitting hole 52 fitted to an outer peripheral surface of the fourth bearing 43, and the cylindrical portion 41 for bearing of the output-side rotating body 7 through the fourth bearing 43. Is supported rotatably. A bearing positioning projection 53 is formed at the axial end of the cylindrical portion 47 and is located on the side of the outer race of the fourth bearing 43. This bearing positioning projection 53 accommodates the fourth bearing 43 between the bearing positioning step 54 of the output side rotating body 7 and prevents the fourth bearing 43 from coming out between the output side rotating body 7 and the cover 8. It is preventing.

  In the ball speed reducer 1 according to the present embodiment as described above, when the input shaft 2 and the eccentric disc cam 3 are integrated and rotated once, the oscillator 4 has an eccentric amount (e) of the eccentric disc cam 3. The ball 5 accommodated in the ball holding portion 23 of the rocking body 4 reciprocates once in the radial groove 30 of the fixing member 6 by being swung by a double size (2e). At this time, the output-side rotator 7 simply moves the ball 5 in the radial groove 30 of the fixing member 6 along the radial direction of the first side surface portion 24, so Is rotated by one wave. Therefore, in the ball speed reducer 1 according to the present embodiment, the wave number of the corrugated groove 31 is N and the number of grooves of the radial groove 30 is (N + 1). The body 7 rotates 1 / N in the opposite direction to the input shaft 2. In the ball speed reducer 1 according to the present embodiment, as shown in FIGS. 4 and 5, the wave number (N) of the corrugated groove 31 of the output side rotating body 7 is 51, and the radial groove 30 of the fixing member 6. In this example, the number of grooves (N + 1) is 52. Therefore, the ball speed reducer 1 according to the present embodiment reduces the rotation of the input shaft 2 to 1/51 (1 / N) and transmits it to the output side rotating body 7.

  Since the ball speed reducer 1 according to the present embodiment configured as described above is configured to form the corrugated groove 31 only in the second side surface portion 40 of the output-side rotator 7 facing the oscillator 4. Compared with the conventional ball reducer 100 in which the corrugated grooves 111, 111, 112, 112 are respectively formed at four locations (see FIG. 14), the number of processing steps can be reduced. Further, in the ball speed reducer 1 according to the present embodiment, the oscillating body 4 and the output side rotator can be independently oscillated with respect to the fixed member 6 and the output side rotator 7. It is not necessary to provide a complicated mechanism (for example, the eccentric absorption mechanisms 113 and 113 of the ball speed reducer 100 according to the conventional example) for integrally rotating the motor 7 and the structure can be simplified and the number of processing steps can be reduced. Become.

  In the ball speed reducer 1 according to the present embodiment, the ball 5 is positioned at the intersection of the radial groove 30 and the corrugated groove 31, so that the ball 108 is the first corrugated of the eccentric rotating plate 104. Compared to the conventional ball reducer 100 configured to simultaneously contact the groove wall of the groove 111 and the groove wall of the second corrugated groove 112 of the fixing member 107 (see FIG. 14), the radial groove 30 and the corrugated groove 31. This makes it easy to assemble the rocking body 4, the fixing member 6, the output side rotating body 7, and the like.

  Further, the ball speed reducer 1 according to the present embodiment increases the groove depth at the valley bottom 31a and the peak 31b of the corrugated groove 31 that is likely to cause ratcheting, and the corrugated groove 31 extends from the valley bottom 31a and the peak 31b of the corrugated groove 31. By reducing the groove depth toward the center of the wave height, it is formed between adjacent waves (between adjacent peak 31b and peak 31b and between adjacent valley bottom 31a and valley bottom 31a). While the height of the ridge line 31c is increased, the gap between the outer edge 31d of the corrugated groove 31 formed by the tool for forming the corrugated groove 31 and the ball 5 is reduced, and the function of holding the ball 5 by the corrugated groove 31 is enhanced. Therefore, the ball 5 located at one peak 31b or the valley bottom 31a of the adjacent wave jumps over the ridge line 31c to the other peak 31b or the valley bottom 31a of the adjacent wave. Ratcheting is less likely to occur that. 5D illustrates the relationship between the tool diameters (D1, D2) for processing the adjacent wave boundaries (intermediate positions) of the corrugated groove 31 and the shape of the outer edge 31d (31e) of the corrugated groove 31. FIG. FIG. As shown in FIG. 5D, the corrugated groove 31 has a tool diameter (tool diameter forming the outer edge 31e of the corrugated groove 31) when the groove depth is constant at the boundary between adjacent waves. On the other hand, if the groove diameter gradually decreases from the peak 31b toward the center of the wave height (the tool diameter that forms the outer edge 31d of the wave groove 31) is D2 (D2 <D1), The gap between the ball 5 and the outer edge 31d of the corrugated groove 31 becomes smaller when the groove depth gradually decreases from the peak 31b toward the center of the wave height than when the groove depth is formed constant. The relationship between the shape of the outer edge 31d on the peak 31b side of the corrugated groove 31 and the tool diameter described in FIG. 5D applies to the relationship between the shape of the outer edge 31f on the valley bottom 31a side of the corrugated groove 31 and the tool diameter. Is done.

  Moreover, since the clearance between the flange part 46 of the cover 8 and the 2nd side part 40 of the output side rotary body 7 is provided in the ball reducer 1 which concerns on this embodiment, rotation of the output side rotary body 7 is carried out. The resistance can be reduced, the power transmission efficiency can be improved, and the amount of clearance between the flange portion 46 of the cover 8 and the second side surface portion 40 of the output-side rotating body 7 can be adjusted, whereby the output side The deformation of the second side surface portion 40 of the rotating body 7 in the direction away from the fixing member 6 can be suppressed by the flange portion 46 of the cover 8, and the ball 5 in the corrugated groove 31 can move along the corrugated groove 31. Therefore, ratcheting caused by jumping from one groove of the adjacent wave to the other groove can be prevented. The adjustment of the gap amount between the flange portion 46 of the cover 8 and the second side surface portion 40 of the output-side rotator 7 is performed, for example, by the protrusion between the cover mounting portion 34 of the fixing member 6 and the flange portion 46 of the cover 8. This can be done by sandwiching a gap adjusting shim (not shown) between the contact surfaces. Ratcheting may also occur between adjacent radial grooves 30,30.

  Further, the ball speed reducer 1 according to the present embodiment is formed on the first side surface portion 24 of the fixing member 6 so that the ball support protrusion 25 protrudes toward the rocking body 4, and the ball holding portion 23 of the rocking body 4 The position where the ball 5 is held is located closer to the second side surface portion 40 of the output side rotating body 7 than the center in the plate thickness direction of the oscillating body 4 (than the intermediate position between both side surfaces 4a and 4b). As a result, the ball speed reducer 1 according to the present embodiment can increase the depth of the corrugated groove 31 of the output-side rotator 7, and can reduce the occurrence of ratcheting during power transmission.

  Further, in the ball speed reducer 1 according to the present embodiment, the contact relief recesses 32, 33, 44 for reducing the contact area by reducing the contact area with the rocking body 4 on the fixed member 6 and the output side rotating body 7 are provided. , 45 are formed in a plurality, the power can be transmitted efficiently. In the ball speed reducer 1 according to the present embodiment, when the contact relief recesses 32, 33, 44, 45 of the oscillating body 4 are filled with grease, the fixed member 6, the output side rotating body 7, and the oscillating body 4 Since the viscous resistance of the grease acting during this period can be reduced, energy loss caused by the viscous resistance of the grease can be reduced, and power transmission can be performed efficiently.

  Further, the ball speed reducer 1 according to this embodiment has a balance weight 17 fixed to the input shaft 2 and maintains the rotational balance of the input shaft when the rocking body 4 is swung by the eccentric disc cam 3. Therefore, it is possible to prevent vibrations and noises caused by imbalance in the rotation balance of the input shaft 2 and to extend the life of the first to fourth bearings.

  Further, in the ball speed reducer 1 according to the present embodiment, when the wave number of the wave groove 31 of the output side rotator 7 is N, the reduction ratio becomes 1 / N, and the ball speed reducer 100 of the conventional example shown in FIG. The reduction ratio can be increased.

(Modification 1 of the first embodiment)
In the ball speed reducer 1 according to the present embodiment, the wave number (N) of the corrugated groove 31 of the output side rotating body 7 is 51 waves, the number of grooves (N + 1) of the radial groove 30 of the fixing member 6 is 52 grooves, The number is 52, but the present invention is not limited to this. The wave number (N) of the corrugated groove 31, the number of grooves (N + 1) of the radial groove 30, and the number of balls 5 are not limited to this. Is determined. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30.

(Modification 2 of the first embodiment)
In the ball speed reducer 1 according to the present embodiment, when the output shaft rotating body 7 is rotated in the same direction as the input shaft 2 without changing the reduction ratio, the wave number of the waveform groove 31 of the output side rotating body 7 is N. Then, the number of radial grooves 30 of the fixing member 6 is (N-1), and the number of balls 5 is (N-1). The radial grooves 30 are arranged at equal intervals along the circumferential direction of the fixing member 6. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30.

(Modification 3 of the first embodiment)
FIG. 7 is a diagram illustrating a third modification of the ball speed reducer 1 according to the present embodiment, and is a diagram illustrating a modification of the radial groove 30 of the fixing member 6. As shown in FIG. 7, the radial groove 30 of the fixing member 6 has a groove number (m) of (N + 1) / 2 when the wave number (N) of the wave groove 31 of the output side rotating body 7 is 51 waves. It is good also as = 26. The number (m) of the balls 5 accommodated in the radial grooves 30 may be (N + 1) / 2 = 26. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30. Further, the present modification is established when the number of grooves m is a natural number with respect to the wave number (N) of the waveform groove 31 of the output side rotator 7. Further, the radial groove 30 of the fixing member 6 may have a groove number (m) of (N−1) / 2 = 25 when the wave number (N) of the waved groove 31 of the output side rotating body 7 is 51 waves. Good. The number (m) of the balls 5 accommodated in the radial grooves 30 may be (N−1) / 2 = 25.

  Compared with the ball speed reducer 1 according to the first embodiment, the ball speed reducer 1 using the fixing member 6 according to the present modified example has the number of balls 5 reduced by half. It becomes possible to reduce (it becomes possible to reduce in weight), and the product cost can be reduced. In addition, the ball speed reducer 1 using the fixing member 6 according to the present modification can increase the ball 5 by the amount that the number of the balls 5 is reduced to half, and the depth of the corrugated groove 31 is increased. Therefore, the occurrence of ratcheting during power transmission can be reduced, and the torque that can be transmitted can be increased.

(Modification 4 of the first embodiment)
FIG. 8 is a view showing a modification of the rocking body 4 of the ball speed reducer 1 according to the first embodiment. FIG. 8A is a longitudinal sectional view of the oscillating body 55 according to this modification (a cross-sectional view of the oscillating body 55 cut along the line A9-A9 in FIG. 8B). FIG. 8B is a front view of the oscillating body 55 according to this modification. FIG. 8C is an enlarged view of the ball holding portion 56 of the rocking body 55.

  The oscillating body 55 according to this modification has a structure in which the inner oscillating ring 21 and the outer oscillating ring 22 according to the first embodiment are integrally connected by a plurality of ribs connected in the radial direction. . That is, the rocking body 55 according to this modification has the same shape as the inner rocking ring portion 57 having the same shape as the inner rocking ring 21 according to the first embodiment and the outer rocking ring 22 according to the first embodiment. An outer swing ring portion 58, a plurality of ribs 60 that connect and integrate the inner swing ring portion 57 and the outer swing ring portion 58, and a ball holding portion formed between adjacent ribs 60, 60 56. The swinging body 55 is configured such that the outer rocking ring part 58 is rocked inward by connecting the outer peripheral side of the inner rocking ring part 57 and the inner peripheral side of the outer rocking ring part 58 with a plurality of ribs 60. It is located concentrically with the ring portion 57. A plurality of ribs 60 are formed at equal intervals along the outer peripheral surface 57 a of the inner rocking ring portion 57. The ball holding portion 56 is a long hole formed along the circumferential direction, and is a semicircular portion 56a (both ends having the same dimensions as the radius R of the ball 5) that are in contact with the generatrix of the ball 5. The distance L between the pair of semicircular portions 56a and 56a positioned so as to be larger than the dimension (2e) twice the eccentric amount (e) of the eccentric disc cam 3 is formed. When the oscillating body 55 formed in this way is used instead of the oscillating body 4 according to the first embodiment, one of the side surfaces 55a of both side surfaces 55a and 55b is the first side surface portion 24 of the fixing member 6. The other side surface 55b of the side surfaces 55a and 55b is disposed so as to oppose the second side surface portion 40 of the output side rotating body 7. The swinging body 55 is not limited in movement (swinging) by the fixing member 6 and the output side rotating body 7, and is smoothly swung with respect to the fixing member 6 and the output side rotating body 7, and the first embodiment. It functions similarly to the rocking body 4 according to the above. Note that in the rocking body 55 according to this modification, when the wave number N of the waved groove 31 of the output-side rotating body 7 is 51, the elongated hole that is the ball holding portion 56 extends along the outer peripheral surface 57a of the inner rocking ring portion 57. 26 balls are formed at equal intervals, and one ball 5 is accommodated in each ball holding portion 56 so as to roll.

  Compared with the ball reducer 1 according to the first embodiment, the ball reducer 1 using the oscillating body 55 according to this modification example is different from the ball reducer 1 according to the first embodiment in which the inner oscillating ring 21 and the outer oscillating ring 22 are separate from each other. Assembly work is facilitated. Further, the ball speed reducer 1 using the rocking body 55 according to the present modification has 26 balls 5 to be used, so that it is compared with the ball speed reducer 1 according to the first embodiment in which the number of balls 5 is 52. As a result, the overall weight can be reduced (the weight can be reduced), and the product cost can be reduced.

(Modification 5 of the first embodiment)
FIG. 9 is a view showing a modification of the wave groove 31 of the output side rotator 7. As shown in FIG. 9, the output-side rotator 7 according to this modification includes a first corrugated groove 61 formed in an annular shape around the rotation center 42 a, a first corrugated groove 61 concentric with the first corrugated groove 61, and the first An annular second corrugated groove 62 is formed on the radially outer side of the corrugated groove 61. When the wave number (N) is 51 waves, the first wave groove 61 and the second wave groove 62 are formed so that the amplitude of the wave becomes the same size as the eccentric amount (e) of the eccentric disc cam 3. Then, 26 ((N + 1) / 2) or 25 ((N−) balls 5 that roll in the first corrugated groove 61 are equally spaced around the rotation center 42a of the output-side rotator 7 (circumferential direction). 1) / 2) It is accommodated in a radial groove (not shown) of the fixing member 6 so as to be arranged. Further, the ball 5 rolling in the second corrugated groove 62 is positioned so as to be shifted from the ball 5 in the first corrugated groove 61 by a half wave along the circumferential direction of the output side rotating body 7. 26 ((N + 1) / 2) or 25 ((N-1) / 2) pieces are arranged around the rotation center 42a (circumferential direction) of the output side rotating body 7 at equal intervals, and the diameter of the fixing member 6 (not shown). Housed in a directional groove. Note that the ball speed reducer 1 in which the output-side rotator 7 according to this modification is used is an oscillating body (not shown) including an inner oscillating ring, an intermediate oscillating ring, and an outer oscillating ring, or an inner side. An oscillating body (not shown) in which the oscillating ring, the intermediate ring, and the outer oscillating ring are connected in a radial direction with ribs is used.

  The ball speed reducer 1 using the output-side rotator 7 according to this modification example is different from the ball speed reducer 1 according to the modification example 3 of the present embodiment in that the output torque fluctuations (from the output-side rotator body 7). (Variation in torque transmitted to the driven member) can be reduced. The size of the ball 5 that rolls in the first corrugated groove 61 is not limited to the same size as the ball that rolls in the second corrugated groove 62. A ball smaller than the moving ball 5 may be used. Further, the ball 5 rolling in the second corrugated groove 62 is not limited to the case where the ball 5 in the first corrugated groove 61 is arranged so as to be shifted by a half wave in the circumferential direction. The ball 5 may be arranged so as to be deviated by less than a half wave in the circumferential direction, or may be arranged so as to be deviated from the ball 5 in the first corrugated groove 61 by a half wave or more in the circumferential direction.

(Modification 6 of the first embodiment)
In the ball reducer 1 according to the first embodiment, the corrugated groove 31 has the same groove depth from the valley bottom 31a to the center of the wave height, and gradually increases the groove depth gradually from the wave height central position toward the peak 31b. The groove depth of the peak 31b may be deepest. Moreover, in this modification, the radial groove 30 gradually increases the groove depth gradually from the position corresponding to the peak 31b of the corrugated groove 31 toward the radial center position, and the valley bottom of the corrugated groove 31 from the radial center position. The groove depth may be constant up to a position corresponding to 31a. In the ball speed reducer 1 in which the corrugated groove 31 and the radial groove 30 according to this modification are formed, the ridgeline 31c formed between adjacent waves (between the adjacent peak 31b and peak 31b). As the height increases, the gap between the outer edge 31d of the corrugated groove 31 formed by the tool for forming the corrugated groove 31 and the ball 5 decreases, and the function of holding the ball 5 by the corrugated groove 31 is enhanced. The ratcheting in which the ball located at one peak 31b of the matching wave jumps over the ridge line 31c to the other peak 31b of the adjacent wave is less likely to occur.

[Second Embodiment]
FIG. 10 is a longitudinal sectional view of the ball speed reducer 1 according to the second embodiment of the present invention. As shown in FIG. 10, the ball speed reducer 1 according to the present embodiment is similar to the ball speed reducer 1 according to the first embodiment in that an input shaft (input side rotating body) 2, an eccentric disc cam 3, The moving body 4, the plurality of balls 5, the fixing member 6, the output side rotating body 7, and the cover 8 are configured. In such a ball speed reducer 1 according to this embodiment, the corrugated groove 31 is formed in the fixed member 6, the radial groove 30 is formed in the output-side rotating body 7, and the swinging body 4 is reversed and used. Except for the point, it is configured in the same manner as the ball speed reducer 1 according to the first embodiment. Accordingly, in the ball speed reducer 1 according to the present embodiment, the same components as those of the ball speed reducer 1 according to the first embodiment are denoted by the same reference numerals, and the description of the ball speed reducer 1 according to the first embodiment is duplicated. Description is omitted.

  As shown in FIGS. 10 and 11, the fixing member 6 has an annular corrugated groove 31 formed on the first side surface portion 24 facing the one side surface 4 a of the both side surfaces 4 a and 4 b of the rocking body 4. . The corrugated groove 31 has the same shape as the corrugated groove 31 formed in the second side surface portion 40 of the output side rotating body 7 of the ball speed reducer 1 according to the first embodiment, and is formed in the ball holding portion 23 of the rocking body 4. The accommodated ball 5 is guided in a wave shape along the circumferential direction of the first side surface portion 24.

  As shown in FIGS. 10 and 12, the output-side rotator 7 is formed on the second side surface portion 40 in which the plurality of radial grooves 30 are opposed to the other side surface 4 b of the both side surfaces 4 a and 4 b of the rocking body 4. Has been. The second side surface portion 40 is formed with a ball support projection 25 similar to the ball support projection 25 formed on the first side surface portion 24 of the fixing member 6 of the ball speed reducer 1 according to the first embodiment. The ball support protrusion 25 is formed with a plurality of radial grooves 30 that engage with the balls 5 accommodated in the ball holding portion 23 of the rocking body 4 at equal intervals along the circumferential direction. The radial groove 30 has the same shape as the radial groove 30 formed in the first side surface portion 24 of the fixing member 6 of the ball speed reducer 1 according to the first embodiment. Further, the number of the grooves in the radial groove 30 is N + 1 when the wave number of the corrugated groove 31 is N, similarly to the number of the radial grooves 30 of the ball reducer 1 according to the first embodiment.

  In the ball speed reducer 1 according to the present embodiment as described above, when the input shaft 2 and the eccentric disc cam 3 are integrated and rotated once, the oscillator 4 has an eccentric amount (e) of the eccentric disc cam 3. The ball 5, which is swung by twice the dimension (2 e) and is accommodated in the ball holding portion 23 of the rocking body 4, is moved in the radial groove 30 of the output side rotating body 7, and the waveform of the fixing member 6 is It can be moved in the groove 31. As a result, in the ball speed reducer 1 according to the present embodiment, when the wave number of the corrugated groove 31 is N, the number of radial grooves is N + 1, and the number of balls 5 is N + 1, 1 of the input shaft 2 With respect to the rotation, the output-side rotator 7 rotates 1 / (N + 1) in the same direction as the input shaft 2.

  Since the ball speed reducer 1 according to the present embodiment configured as described above is configured to form the corrugated groove 31 only in the first side surface portion 24 of the fixing member 6 facing the oscillator 4, the corrugated groove Compared to the conventional ball speed reducer 100 in which 111, 111, 112, and 112 are formed at four locations, respectively (see FIG. 14), the number of processing steps can be reduced. Further, in the ball speed reducer 1 according to the present embodiment, the swinging body 4 can swing independently with respect to the output side rotating body 7 and the fixed member 6 in the same manner as the ball speed reducer 1 according to the first embodiment. Therefore, it is not necessary to provide a complicated mechanism (for example, the eccentric absorption mechanisms 113 and 113 of the conventional ball speed reducer 100) for rotating the rocking body 4 and the output side rotating body 7 together. As a result, the structure is simplified and the number of processing steps can be reduced.

  In addition, the ball speed reducer 1 according to the present embodiment has the same function as the ball speed reducer 1 according to the first embodiment in the radial groove 30 and the corrugated groove 31, so that the function of holding the ball 5 by the corrugated groove 31 is enhanced. Thus, ratcheting in which the ball 5 located at one peak 31b or valley bottom 31a of the adjacent wave jumps over the ridge line 31c to the other peak 31b or valley bottom 31a of the adjacent wave is less likely to occur.

(Modification 1 of 2nd Embodiment)
In the ball speed reducer 1 according to the present embodiment, the wave number (N) of the corrugated groove 31 of the fixing member 6 is 51 waves, the number of grooves (N + 1) of the radial groove 30 of the output shaft rotating body 7 is 52 grooves, The number is 52, but the present invention is not limited to this. The wave number (N) of the corrugated groove 31, the number of grooves (N + 1) of the radial groove 30, and the number of balls 5 are not limited to this. Is determined. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30.

(Modification 2 of the second embodiment)
In the ball speed reducer 1 according to the present embodiment, the wave number of the corrugated groove 31 of the fixing member 6 is N, the number of the radial grooves 30 of the output shaft rotating body 7 is (N−1), and the ball 5 When the number is (N−1), when the input shaft rotates once, the output-side rotating body 7 rotates 1 / (N−1) in the opposite direction to the input shaft 2. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30.

(Modification 3 of 2nd Embodiment)
FIG. 13 is a diagram illustrating a third modification of the ball speed reducer 1 according to the present embodiment, and is a diagram illustrating a modification of the radial groove 30 of the output-side rotator 7. As shown in FIG. 13, when the wave number (N) of the corrugated groove 31 of the fixing member 6 is 51 waves, the radial groove 30 of the output side rotator 7 has a groove number (m) of (N + 1) / 2. It is good also as = 26. The number (m) of the balls 5 accommodated in the radial grooves 31 may be (N + 1) / 2 = 26. In addition, as long as the smooth rotation transmission of the ball reducer 1 is not impaired, the balls 5 may be arranged to be smaller than the number of the radial grooves 30. Further, the present modification is established when the number of grooves m is a natural number with respect to the wave number (N) of the corrugated grooves 31 of the fixing member 6. Further, the radial groove 30 of the output-side rotator 7 may have a groove number (m) of (N−1) / 2 = 25 when the wave number (N) of the corrugated groove 31 of the fixing member 6 is 51 waves. Good. The number (m) of the balls 5 accommodated in the radial grooves 30 may be (N−1) / 2 = 25.

  Compared with the ball reducer 1 according to the second embodiment, the ball reducer 1 using the output-side rotator 7 according to this modified example has the number of balls 5 reduced by half, It became possible to reduce the weight (it became possible to reduce the weight), and it became possible to reduce the product cost.

(Modification 4 of the second embodiment)
Further, the ball speed reducer 1 according to the present embodiment can be used in place of the rocking body 55 shown in FIG. 8 in place of the rocking body 4 shown in FIG. 8, as in the fourth modification of the first embodiment. The effect similar to the modification 4 of 1st Embodiment can be acquired.

(Modification 5 of the second embodiment)
Further, in the ball speed reducer 1 according to the present embodiment, similarly to the fifth modification of the first embodiment, the corrugated groove 31 of the fixing member 6 illustrated in FIG. In the first corrugated groove 62, 26 (or 25) balls 5 positioned at equal intervals are accommodated in the radial groove 30 formed in the output side rotating body 7, and the second corrugated groove 62 is obtained. 26 (or 25) balls 5 positioned at equal intervals in the groove 62 are accommodated in a radial groove 30 formed in the output-side rotating body 7, and the balls 5 in the radial groove 30 are adjusted in diameter by the oscillator 4. You may make it roll in a direction. According to such a modification, the same effect as that of Modification 5 of the first embodiment can be obtained.

[Modification of First and Second Embodiments]
In the ball speed reducer 1 according to the first and second embodiments, as illustrated in FIGS. 1 and 10, ball bearings are exemplified as the first to fourth bearings 11, 15, 18, and 43. However, the present invention is not limited to this. Roller bearings, bushes, etc. may be used instead of ball bearings.

  In the ball speed reducer 1 according to the first and second embodiments, the whole (the input shaft 2, the oscillating bodies 4, 55, the fixing member 6, the output side rotating body 7, the cover 8, etc.) is formed of metal. A case where a part of the whole is formed of a synthetic resin material, or a case where the whole other than the first to fourth bearings 11, 15, 18, 43 and the ball 5 is formed of a synthetic resin material can be considered. In particular, the ball speed reducer 1 according to the first and second embodiments reduces the weight when the entirety other than the first to fourth bearings 11, 15, 18, 43 and the ball 5 is formed of a synthetic resin material. Product price can be reduced. In the first and second embodiments, when the ball speed reducer 1 is formed entirely of a synthetic resin material other than the first to fourth bearings 11, 15, 18, 43 and the ball 5, the ball reducer 1 generates a contact sound with the ball. It is possible to reduce (can reduce noise) and suppress vibration. In the ball speed reducer 1 according to the first and second embodiments, when the rocking body 4 is formed of a synthetic resin material, the ball 5 is pressed toward the inner rocking ring 21 by the elastic force of the outer rocking ring 22. It is possible to prevent the ball 5 from violating in the ball holding portion 23 (rattle).

  In the ball speed reducer 1 according to the first and second embodiments, when the wave number of the corrugated groove 31 is N, the number of the radial grooves 30 and the balls 5 is (N + 1) / 2 or (N-1) / 2. However, the present invention is not limited to this, and the number (m) of the radial grooves 30 and the balls 5 may be (N + 1) / 3 or (N-1) / 3. In this case, the number (m) of the radial grooves 30 and the balls 5 is a natural number, (N + 1) is a multiple of 3, and (N−1) is a multiple of 3.

  In the ball speed reducer 1 according to the first and second embodiments, when the number (m) of the radial grooves 30 and the balls 5 is smaller than the wave number (N) of the corrugated grooves 31, the radial grooves 30 and the balls It is preferable to determine the number of radial grooves 30 and the number of balls 5 (m) so that 5 are positioned at equal intervals (equal) in the circumferential direction. The ball speed reducer 1 configured in this way is capable of smooth power transmission without causing torque fluctuations due to uneven arrangement of the radial grooves 30 and the balls 5 in the circumferential direction during power transmission. Enable.

  DESCRIPTION OF SYMBOLS 1 ... Ball reducer, 2 ... Input shaft (input side rotary body), 2a ... Center of rotation, 3 ... Eccentric disk cam, 4, 55 ... Oscillator, 4a, 4b, 55a, 55b ... Side surface, 5... Ball, 6... Fixing member, 7... Output side rotating body, 23 and 56... Ball holding portion, 24. ... Wave groove, 31a ... Valley bottom, 31b ... Mountain peak, 40 ... Second side surface part, 42a ... Rotation center (axial center)

Claims (2)

In the ball reducer that decelerates and transmits the rotation of the input side rotator to the output side rotator,
An eccentric disc cam that rotates integrally with the input side rotating body;
An oscillating body that is fitted to the outer peripheral side of the eccentric disc cam so as to be relatively rotatable, and is oscillated by the eccentric disc cam;
A plurality of balls housed in the ball holding portion of the rocking body;
A first member having a first side surface located opposite to one of the two side surfaces of the oscillator, and a fixing member fixed to the member to be fixed,
The ball holding portion of the oscillating body is formed along a relative rotation direction of the oscillating body and the eccentric disk cam, and accommodates the plurality of balls so as to roll along the relative rotation direction. ,
The output-side rotator has a second side surface portion facing the other of the two side surfaces of the oscillating body, and an axis as a rotation center is coaxial with the rotation center of the input-side rotator. Arranged to be located,
When one of the first side surface portion and the second side surface portion is a virtual plane orthogonal to the rotation center of the input-side rotator and the direction radially extending from the rotation center is a radial direction, the ball is A plurality of radial grooves that are rotatably guided along the radial direction of either the first side surface portion or the second side surface portion are formed around the rotation center of the input shaft side rotating body,
When the other side of the first side surface portion and the second side surface portion has a circumferential direction in the virtual plane along the outer edge of a virtual circle centered on the rotation center, the ball is moved to the first side surface. An annular corrugated groove is formed that guides in a wave shape along the circumferential direction of the other of the portion and the second side surface portion,
The ball is slidably engaged with the radial groove and the corrugated groove, and when the swinging body is swung by the eccentric disk cam, the ball rolls within the radial groove and the corrugated groove. And
The corrugated groove has a radially inner end as a valley bottom, a radially outer end as a mountain peak, and an intermediate position between the valley bottom and the mountain peak as a wave height central position, the groove depth of the mountain peak corresponds to the wave height. It is deeper than the groove depth at the center, and is formed so that the groove depth changes smoothly.
The radial groove corresponds to the peak when the radial position corresponding to the wave height central position of the corrugated groove is a radial intermediate position, and the radial position corresponding to the peak of the corrugated groove is a peak corresponding position. The groove depth at the position is shallower than the groove depth at the radial intermediate position, and the groove depth is formed to change smoothly.
A ball reducer characterized by that. The corrugated groove is formed such that the groove depth of the valley bottom is deeper than the groove depth of the wave height central position, and the groove depth changes smoothly,
When the radial position corresponding to the valley bottom of the corrugated groove is a valley bottom corresponding position, the groove in the radial groove is shallower than the groove depth in the radial middle position, and the groove depth is Formed to change smoothly,
The ball speed reducer according to claim 1.

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