JP2013057397A - Wave gear speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase torsional rigidity.SOLUTION: In a wave gear speed reducer 190, a rotation of an input shaft causes two planetary rollers 3 to rotate inside a ring external gear 6a engaging with an internal gear 7a while revolving to elastically deform the external gear 6a in an ellipse, and changing two engagement positions of the internal gear and the external gear causes the rotation of the input shaft 11 to be transmitted to an output shaft 13 connected to the external gear while a speed of the rotation is reduced. The wave gear speed reducer includes an elastically-deformable flex ring 5 between the external gear and the planetary roller. The flex ring can inhibit the external gear in the vicinity in a circumferential direction of the planetary roller from bending toward the inside of the ellipse. Accordingly, the number of engagement gears between the external gear and the internal gear is increased and the torsional rigidity in a structure on an output shaft side can be improved.

Description

  The present invention relates to a wave gear reducer that can obtain a high reduction ratio by utilizing the operation of an internal gear and an elliptical external gear that mesh with each other.

  A wave gear reducer consists of a circular spline as a rigid internal gear, a flex spline as an external gear with an elastic body with fewer teeth than the circular spline, and a wave generator that contacts the inside of the flex spline. ing.

  The wave generator has a structure in which an elastically deformable bearing is mounted on the outer periphery of a cam plate connected to an input shaft and formed in an ellipse. The bearing is composed of a steel ball, an outer ring, an inner ring, and a retainer. The steel balls are arranged between the inner ring and the outer ring and are arranged at equal intervals by a retainer. In addition, the steel ball moves relative to the inner ring and the outer ring in the circumferential direction while rotating and rotating, and is held in the thrust direction by grooves formed on the outer side of the inner ring and the inner side of the outer ring. Rotates relatively smoothly. Further, when the bearing is a single product, it is circular, and when an elliptical cam plate is inserted inside the inner ring of the bearing, the inner ring elastically deforms into an elliptical shape following the cam plate. Following the inner ring deformed into an ellipse, the outer ring is also elastically deformed into an ellipse via a steel ball. A flexspline is attached to the outer periphery of the outer ring of the bearing. When the input shaft rotates, the wave generator transmits rotational force to the flexspline while elastically deforming the outer ring of the bearing into an ellipse. At this time, the flexspline is also elastically deformed into an ellipse.

  Then, the meshing positions of the two external teeth near the major axis of the flexspline elastically deformed into an ellipse and the inner teeth of the circular spline are sequentially changed. For this reason, every time the input shaft rotates once, the flexspline rotates by the difference in the number of teeth from the circular spline. The flexspline is provided with an output shaft, and the rotation of the input shaft is decelerated and taken out from the output shaft. As described above, the wave gear reducer has a feature that a high reduction ratio can be obtained without backlash although the number of parts is small.

  However, the outer ring and flexspline of the elastically deforming bearing have a problem that it is difficult to design and process and is expensive.

  In particular, the outer ring of the elastically deforming bearing has a problem that the design and processing are special and costly because it is necessary to allow elastic deformation while the thickness accuracy of the thickness in the radial direction is high.

  Therefore, a wave gear reducer that addresses these problems is disclosed in Patent Document 1. As schematically shown in FIGS. 13 to 15, the wave gear reducer includes a wave generator 917 including a holding member 901 provided on an input shaft 909 and a bearing 904 as a planetary roller. The wave gear reducer 990 includes a circular spline 907 as an internal gear fixed to a frame 908, and a flex spline 906 that is provided on the output shaft 913 and elastically deforms as an external gear. . The flex spline 906 is deformed into an ellipse by the six bearings 904, and meshes with the teeth of the circular spline 907 in the vicinity of the two major diameters. In this configuration, since the bearing 904 does not need to be elastically deformed, a commercially available bearing can be used, and the wave generator 917 can be reduced in cost.

  The torque of the output shaft 913 is received by the flex spline 906 through the cup-shaped flex spline 906 and the external teeth near the major axis of the flex spline 906 elastically deformed into an ellipse mesh with the internal teeth of the circular spline 907. . For this reason, the thickness in the radial direction of the flexspline 906 is a thickness that simultaneously satisfies the contradictory condition of being able to be elastically deformed into an ellipse and obtaining torsional rigidity to receive torque from the output shaft 913. It has become. Further, the torque from the output shaft 913 is decomposed into a radial load and a circumferential load applied in the radial direction and inward by the pressure angle of the gear near the major axis of the flexspline 906 deformed into an ellipse. This radial load is received by the bearing 904 inside the flexspline 906, and the circumferential load is received by the circular spline 907.

Japanese Utility Model Publication No. 63-125247

  However, in the conventional wave gear reducer 990, the flex spline 906 near the bearing in the circumferential direction may be bent inside the ellipse along the curvature of the bearing 904 due to the radial load (see the broken line in FIG. 14). Note that the broken line is exaggerated for easy understanding of the bending, but in actuality, the bending is not so much. Due to this bending, the outer teeth of the flex spline 906 are separated in the radial direction and do not mesh with the inner teeth of the circular spline 907. As a result, there is a problem that the torsional rigidity of the structure on the output shaft side is lowered.

  An object of the present invention is to provide a wave gear reducer having high torsional rigidity while having a low-cost configuration using planetary rollers.

  In the wave gear reducer according to the present invention, the rotation of the input shaft causes the two planetary rollers to rotate while revolving inside the ring-shaped external gear that meshes with the internal gear to make the external gear into an oval shape. An output shaft connected to one of the external gear and the internal gear by elastically deforming and changing the meshing position of the two positions of the internal gear and the external gear And a flex ring that is elastically deformable between the external gear and the planetary roller.

  In the wave gear reducer according to the present invention, the flex ring can suppress the external gear in the vicinity of the planetary roller in the circumferential direction from being bent to the inside of the ellipse. Therefore, the number of meshing teeth between the external gear and the internal gear can be reduced. To increase the torsional rigidity of the structure on the output shaft side.

It is sectional drawing along the rotating shaft of the wave gear reducer of Embodiment 1 of this invention. It is AA arrow sectional drawing of FIG. FIG. 3 is a cross-sectional view taken along line BB in FIG. It is sectional drawing of the flex ring in which the groove | channel which a planetary roller approached was formed along the circumferential direction of an inner periphery. It is sectional drawing of the planetary roller with which the outer periphery roller was mounted | worn on the outer periphery of the bearing. It is sectional drawing of the planetary roller with which the outer periphery roller was mounted | worn on the outer periphery of the bearing. It is sectional drawing of the flex ring in which the groove | channel which hold | maintains a lubricant was formed along the circumferential direction of an outer periphery. It is sectional drawing of the flex ring in which the circular arc surface where the middle of the axial direction was middle-high was formed. (A) is a figure corresponded in BB arrow sectional drawing of FIG. (B) is a figure equivalent to CC sectional view taken on the line of FIG. (C) is a figure corresponded to DD sectional view taken on the line of FIG. It is sectional drawing of the flex ring in which the taper part was formed in the outer periphery. (A) is a figure corresponded in BB arrow sectional drawing of FIG. (B) is a figure equivalent to CC sectional view taken on the line of FIG. It is sectional drawing of the flex ring which provided the resin member in the outer periphery. (A) is a figure corresponded in BB arrow sectional drawing of FIG. (B) is a figure equivalent to CC sectional view taken on the line of FIG. It is sectional drawing of the planetary roller with which the outer periphery roller was mounted | worn on the outer periphery of the bearing. (A) is a figure corresponded in BB arrow sectional drawing of FIG. (B) is a figure equivalent to CC sectional view taken on the line of FIG. It is sectional drawing along the input shaft and output shaft of the wave gear reducer of other embodiment. It is sectional drawing along the input shaft and output shaft of the conventional wave gear reducer. It is EE arrow sectional drawing of FIG. FIG. 15 is a cross-sectional view taken along the line FF in FIG.

  Hereinafter, a wave gear reducer according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In addition, a numerical value is a reference numerical value, Comprising: This invention is not limited.

  FIG. 1 is a cross-sectional view taken along an input shaft and an output shaft of a wave gear reducer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG.

  First, the wave gear reducer will be outlined.

  The wave gear reducer 190 of the present invention is characterized in that a flex ring 5 that is elastically deformable is provided between the flex spline 6 and the main planetary roller 3 and the auxiliary planetary roller 4. When the input shaft 11 rotates, the two main planetary rollers 3 and the four auxiliary planetary rollers 4 rotate while revolving in the flex ring 5 inside the ring-shaped flexspline 6 that meshes with the circular spline 7. As a result, the flex spline 6 and the flex ring 5 are elastically deformed into an oval shape, and the two meshing positions of the circular spline 7 and the flex spline 6 are changed. As a result, the wave gear reducer 190 can transmit the rotation of the input shaft 11 to the output shaft 13 connected to the flexspline at a reduced speed.

  Next, the wave gear reducer will be described in detail.

  In the wave gear reducer 190, components are housed in a frame 8 formed by combining two divided first and second divided frames 8A and 8B. In FIG. 1, an input shaft 11 is rotatably provided by an input shaft bearing 12 in the left first divided frame 8A. The input shaft 11 is connected to a drive source (not shown). In FIG. 1, an output shaft 13 is rotatably provided by an output shaft bearing 14 in the right second divided frame 8B.

  The wave gear reducer 190 includes a circular spline 7 having inner teeth formed on a hollow annular inner diameter surface and fixed to the second divided frame 8B. Further, the wave gear reducer 190 is a flex spline that has 2n teeth (n is a positive integer), for example, two fewer external gears than the internal gear of the circular spline 7 and has flexibility. 6 is provided. Further, the wave gear reducer 190 also includes a wave generator 17 that bends the flexspline 6 into a substantially elliptical shape and engages the circular spline 7 and the flexspline 6 at two locations of the long diameter portion thereof.

  The input shaft 11 is provided with an elliptical holding member 1 that rotates integrally with the input shaft 11. A main planetary roller 3 and an auxiliary planetary roller 4 are provided on the outer periphery of the holding member 1 by a support shaft 2. The main planetary roller 3 is composed of a bearing 3A and a support shaft 2, and the auxiliary planetary roller 4 is composed of a bearing 4A and a support shaft 2. On the outer periphery of the holding member 1, a recess 1a for receiving the bearings 3A and 4A and a notch 1b for receiving the support shaft 2 are formed. The notches 1b are formed radially.

  The main planetary roller 3 is positioned at both ends of the long diameter of the elliptical holding member 1 by the engagement between the support shaft 2 and the notch 1b and is rotatably provided. The auxiliary planetary roller 4 is rotatably provided by being positioned by engagement of the support shaft 2 and the notch 1b at a position deviating from the long diameter of the elliptical holding member 1 adjacent to the main planetary roller 3. That is, the distance r1 between the center of the main planetary roller 3 and the input shaft 11 is longer than the distance r2 between the center of the auxiliary planetary roller 4 and the input shaft 11 (r1> r2). In this case, the diameters of the outer rings of the bearings 3A and 4A are the same. For convenience, six main planetary rollers 3 and auxiliary planetary rollers 4 are provided.

  The holding member 1, the support shaft 2, the main planetary roller 3, and the auxiliary planetary roller 4 form a wave generator 17. The main planetary roller 3 and the auxiliary planetary roller 4 are attached to the input shaft 11 by inserting the support shaft press-fitted into the inner ring of the bearing into the recess 1a of the holding member 1 while inserting it into the notch 1b. Therefore, in the wave generator 17, when the input shaft 11 rotates, the holding member 1, the support shaft 2, the main planetary roller 3, and the auxiliary planetary roller 4 rotate integrally. For this reason, the main planetary roller 3 and the auxiliary planetary roller 4 revolve around the revolution axis 9 that is the axis of the input shaft 11 and rotate around the rotation axis 10 that is the axis of the support shaft 2. It has become.

  The flex ring 5 as a cylindrical member is a ring-shaped member having thin elasticity, and is attached to the outer rings of the main planetary roller 3 and the auxiliary planetary roller 4 and is formed in an elliptical shape.

  The flex spline 6 is formed in a thin cup shape, and one end thereof is attached to the output shaft 13. An external gear 6a is formed on the outer periphery of the tip which is the cup-shaped other end. The flex spline 6 is in contact with the outer periphery of the flex ring 5 and slides in the circumferential direction with respect to the flex ring 5 by the revolution and rotation of the main planetary roller 3 and the auxiliary planetary roller 4. It is elastically deformed into a shape.

  The circular spline 7 is formed in a ring shape and is fixed to the second divided frame 8 </ b> B of the frame 8. An internal gear 7 a that meshes with the external gear 6 a of the flex spline 6 is formed on the inner surface of the circular spline 7. The number of teeth of the circular spline 7 is 2n more (n is a positive integer) than the number of teeth of the flexspline 6. The internal gear 7a of the circular spline 7 includes an external gear 6a of the flexspline 6 that is elastically deformed into an ellipse by the main planetary roller 3, the auxiliary planetary roller 4, and the flex ring 5, and two of the main planetary roller 3 near the major axis of the ellipse. It meshes at the place (Fig. 2).

  In the above configuration, the rotation center of the input shaft 11, the holding member 1, the flex ring 5, the flex spline 6 and the output shaft 13 and the center of the circular spline 7 are coincident with each other on the revolution axis 9.

  Next, the operation of the wave gear reducer 190 will be described.

  When the holding member 1 connected to the input shaft 11 rotates around the revolution axis 9, the convenient six planetary rollers 3 and auxiliary planetary rollers 4 arranged around the holding member 1 are connected to the flex ring 5. Move to roll on the inner surface. That is, the main planetary roller 3 and the auxiliary planetary roller 4 rotate around the rotation axis 10 while revolving around the rotation axis 9.

  Due to the movement of the main planetary roller 3, the ellipse major axis position of the flex ring 5 and the flex spline 6 on its outer side also moves while elastically deforming. For this reason, the positions of the two positions where the external gear 6a of the flexspline 6 and the internal gear 7a of the circular spline 7 are also moved. With this movement of the meshing position, every time the holding member 1 rotates, the flex spline 6 rotates at a reduced speed by a difference in the number of teeth from the circular spline 7.

  In this way, the flex ring 5 and the flex spline 6 are arranged so as to contact each other so as to slide in the circumferential direction. For this reason, compared with the case where the thickness of the flexspline 6 is increased by the thickness of the flex ring 5, the maximum stress at the time of elliptical deformation can be relaxed. The flex ring 5 and the flex spline 6 can both be elastically deformed into an ellipse. On the other hand, the flex ring 5 has an elliptical shape along the curvature of the main planetary roller 3 when a radial and inward radial load is applied to the flexspline 6 near the circumferential direction of the main planetary roller 3. It acts to suppress bending inward. In other words, it is possible to prevent bending as in the conventional flex spline 906 indicated by a broken line in FIG. Thereby, it is possible to prevent the number of meshing teeth between the external gear 6a of the flexspline 6 and the internal gear 7a of the circular spline 7 from decreasing.

  Therefore, the wave gear reducer 190 is configured so that the number of meshing teeth between the external gear 6a of the flexspline 6 and the internal gear 7a of the circular spline 7 is larger than that of the conventional example using the planetary roller. It has come to accept the torque of. For this reason, the torsional rigidity of the output shaft 13 can be increased. Further, in the conventional wave gear reducer using the elastic deformation bearing, it is necessary to process the surface where the inner ring and the outer ring are in contact with the steel ball with high precision. However, since the present invention does not have an inner ring, an inexpensive configuration is possible. It becomes. As a result, the present invention can provide a wave gear reducer having a high torsional rigidity while maintaining an inexpensive configuration using planetary rollers.

  The flex ring 5 is manufactured in a perfect circle and then elastically deformed into an elliptical shape by the main planetary roller 3 and the auxiliary planetary roller 4. The thickness of the flex ring 5 is set so as to be within the elastic range of the material used for the flex ring 5 when deformed into an ellipse. That is, the thickness of the flex ring 5 is set to a thickness at which the flex ring 5 is not plastically deformed. If the flex ring is made of the material SUJ2, is a perfect circle with an outer diameter of 60 mm, and has a thickness of about 1.75 mm, the amount of deformation of the long diameter when the flex ring is deformed into an ellipse is about 1 mm. The maximum stress is in the elastic region of SUJ2.

  In the above description, the distance r1 between the center of the main planetary roller 3 and the input shaft 11 is longer than the distance r2 between the center of the auxiliary planetary roller 4 and the input shaft 11 (r1> r2), and the bearings 3A and 4A. The outer ring has the same diameter. However, this setting is not necessarily required. If the external gear near the major axis of the flexspline 6 is engaged with the internal gear of the circular spline 7 and the external gear near the minor axis of the flexspline 6 is set apart from the internal gear of the circular spline 7. Good.

  The auxiliary planetary roller 4 is not necessarily required. Only the main planetary roller 3 may be used. If only the main planetary roller 3 is used, the flex ring 5 is longer than that shown in FIG. 2, and therefore the inner circumference of the flex ring 5 may come into contact with the outer circumference of the elliptical holding member 1. For this reason, it is necessary to make the shape of the holding member 1 longer than that in FIG. 2 so that the flex ring 5 does not come into contact.

  In addition, as shown in FIG. 4, the flex ring 5 may form a groove 5a along the circumferential direction of the inner periphery, and the main planetary roller 3 and the auxiliary planetary roller 4 may enter the groove 5a. In this case, when the holding member 1 is rotated by the input shaft 11, the main planetary roller 3 and the auxiliary planetary roller 4 move so as to roll on the groove 5 a of the flex ring 5.

  With such a structure, the flex ring 5 can be prevented from coming off from the main planetary roller 3 and the auxiliary planetary roller 4 when the flex ring 5 receives axial force (thrust direction) from the flex spline 6. it can.

  Therefore, the wave gear reducer can reliably transmit the rotation of the input shaft to the output shaft.

  In addition, the flex ring 5 of FIGS. 7 to 10 to be described later is also formed with a groove 5a in which the outer ring of the bearings 3A and 4A engages along the circumferential direction of the inner periphery, so that the main planetary roller 3 and the auxiliary planetary roller 4 are engaged. It is prevented from coming off.

  Further, as shown in FIG. 5, a ring-shaped outer peripheral roller 16 may be mounted on the outer periphery of the outer ring 3 </ b> Aa of the bearing 3 </ b> A of the main planetary roller 3. The outer ring 3Aa and the outer peripheral roller 16 are integrated. A circumferential groove 16 a is formed on the outer periphery of the outer peripheral roller 16. A protrusion 5 b is formed in the circumferential direction of the inner periphery of the flex ring 5. The groove 16a and the protrusion 5b are engaged with each other. An outer peripheral roller (not shown) is also mounted on the outer periphery of the outer ring of the bearing 4A of the auxiliary planetary roller 4 to form a groove that engages with the protrusion 5b formed in the circumferential direction of the inner periphery of the flex ring 5. Good. In addition, as shown in FIG. 6, the groove | channel 5c may be formed in the flex ring 5, and the outer peripheral part (equivalent to a protrusion) of the outer peripheral roller 16 may engage with the groove | channel 5c.

  With this structure, when the flex ring 5 receives axial force (thrust direction) from the flex spline 6, the flex ring 5 is prevented from coming off from the main planetary roller 3 and the auxiliary planetary roller 4. Can do.

  Therefore, the wave gear reducer can reliably transmit the rotation of the input shaft to the output shaft.

  Furthermore, the radial load received by the steel balls of the bearing 3A of the main planetary roller 3 can be dispersed to the steel balls in the periphery of the long diameter. Therefore, durability of the wave gear reducer is improved.

  Further, as shown in FIG. 7, three (not limited to three) grooves 5 d are formed as concave portions for holding the lubricant along the circumferential direction of the outer periphery of the flex ring 5. A recess may be formed instead of the groove 5d.

  With such a structure, since the lubricant is held in the groove 5d on the outer periphery of the flex ring 5, the friction between the flex spline 6 and the flex ring 5 can be reduced. The flex ring 5 shown in FIGS. 5 and 6 may also have grooves 5d formed along the circumferential direction of the outer periphery.

  Therefore, the wave gear reducer can improve the durability by reducing the progress of wear in both the flex spline 6 and the flex ring 5.

  In addition, as shown in FIG. 8, the outer periphery of the flex ring 5 may be formed as a middle-high arc surface 5 e in the middle in the axial direction so that the arc surface 5 e contacts the inner periphery of the flex spline 6. FIG. 8A is a view corresponding to the cross-sectional view taken along the line BB in FIG. FIG. 8B is a view corresponding to the cross-sectional view taken along the line CC in FIG. FIG. 8C is a diagram corresponding to the cross-sectional view taken along the line DD in FIG.

  Since the flex spline 6 has flexibility, as shown in FIGS. 8A, 8B, and 8C, the portion in contact with the main planetary roller 3 and the auxiliary planetary roller 4 The portions that are in contact and the portions that are not in contact with the planetary roller have different ways of bending. The portion in contact with the main planetary roller 3 spreads as shown in FIG. 8A, and the portion in contact with the auxiliary planetary roller 4 hardly spreads as shown in FIG. The part which is not narrowed as shown in FIG. In this way, the flexspline 6 expands, narrows and elastically deforms. Therefore, as in the flex ring 5 shown in FIG. 4, if the arc surface is not formed, the corners of the flex ring 5 abut against the flex spline 6, and local wear occurs in the flex ring 5 and the flex spline 6. There is a fear.

  However, when the arc surface 5e is formed on the outer periphery of the flex ring 5, the flex spline 6 comes into contact with the entire outer periphery of the flex ring 5 substantially uniformly as shown in FIGS. 8 (A), (B), and (C). And the local wear is reduced. The arc surface may be formed on the inner periphery of the flexspline 6. Even in this case, since the flex spline 6 comes into contact with the entire outer periphery of the flex ring 5 substantially uniformly, local wear on the flex ring 5 and the flex spline 6 is reduced.

  Therefore, the wave gear reducer can improve durability by preventing local wear from occurring in the flex ring 5 and the flex spline 6.

  Further, as shown in FIG. 9, a tapered portion 5 f having a reduced diameter toward the input shaft is formed on the outer periphery of the flex ring 5 so that the tapered portion 5 f contacts the inner periphery of the flex spline 6. Also good. FIG. 9A is a diagram corresponding to the cross-sectional view taken along the line BB in FIG. FIG. 9B is a view corresponding to a cross-sectional view taken along the line CC in FIG.

  Since the flexspline 6 has flexibility, as shown in FIGS. 9A and 9B, the portion in contact with the main planetary roller 3 and the auxiliary planetary roller 4 are in contact with each other. The bending method is different from the portion. In the flex spline 6, the portion in contact with the main planetary roller 3 spreads as shown in FIG. 9A, and the portion in contact with the auxiliary planetary roller 4 hardly spreads out as shown in FIG. 9B. . The portion of the flexspline 6 corresponding to the cross-sectional view taken along the line CC in FIG. 2 is narrowed as shown in FIG.

  According to this, even if the cup-shaped flexspline 6 is tilted around the major axis of the ellipse (FIG. 9A), the flexspline 6 and the flex ring are inclined because the flex ring 5 has the same tilt as the tilt. The contact area of 5 increases.

  Therefore, the wave gear reducer can improve the radial rigidity of the flex spline 6 at the meshing portion between the external teeth of the flex spline 6 and the internal teeth of the circular spline 7 and increase the torsional rigidity on the output shaft side. it can.

  Further, as shown in FIG. 10, a thin cylindrical resin member 15 is provided along the circumferential direction of the outer periphery of the flex ring 5, and the resin member 15 is in a pressure contact state between the flex ring 5 and the flex spline 6. May be interposed. FIG. 10A is a diagram corresponding to the cross-sectional view taken along the line BB in FIG. FIG. 10B is a diagram corresponding to the cross-sectional view taken along the line CC in FIG.

  Since the flexspline 6 has flexibility, as shown in FIGS. 10A and 10B, a portion where the main planetary roller 3 is in contact via the resin member 15 and an auxiliary planet The way in which the roller 4 is in contact is different. In the flex spline 6, the portion in contact with the main planetary roller 3 spreads as shown in FIG. 10A, and the portion in contact with the auxiliary planetary roller 4 hardly spreads out as shown in FIG. 10B. . The portion of the flex spline 6 corresponding to the cross-sectional view taken along the line CC in FIG. 2 is narrowed as shown in FIG. In this way, the flex spline 6 is configured to open, narrow, or elastically deform.

  Thereby, as for the cup-shaped flexspline 6, the inclination of the flexspline 6 changes as the ellipse major axis of the holding member 1 moves. Following the inclination, the pressurized resin member 15 is deformed, and the contact area between the flex spline 6 and the flex ring 5 hardly changes as shown in FIGS.

  Therefore, the wave gear reducer improves the radial rigidity of the flex spline 6 at the meshing portion between the external gear of the flex spline 6 and the internal gear of the circular spline 7 and increases the torsional rigidity on the output shaft side. can do.

  Further, as shown in FIG. 11A, a ring-shaped outer peripheral roller 16 may be attached to the outer periphery of the outer ring 3Aa of the bearing 3A of the main planetary roller 3. The outer ring 3Aa and the outer peripheral roller 16 are integrated. An arc convex surface 16 b is formed in the axial direction of the outer periphery of the outer peripheral roller 16, and an arc concave surface 5 g that engages with the arc convex surface 16 b is formed in the axial direction of the inner periphery of the flex ring 5. As shown in FIG. 11 (B), the outer peripheral roller 16 is integrally mounted on the outer periphery of the outer ring 4Aa of the bearing 4A of the auxiliary planetary roller 4 as well. The outer peripheral roller 16 is also formed with an arc convex surface 16 b that engages with the arc concave surface 5 g of the flex ring 5. FIG. 11A is a view corresponding to the cross-sectional view taken along the line BB in FIG. FIG. 11B is a diagram corresponding to a cross-sectional view taken along the line CC in FIG.

  Since the flexspline 6 is flexible, the portion where the main planetary roller 3 is in contact is spread as shown in FIG. 11A, and the portion where the auxiliary planetary roller 4 is in contact is shown in FIG. It hardly spreads as in B). The portion of the flex spline 6 corresponding to the cross-sectional view taken along the line CC in FIG. 2 is narrowed as shown in FIG.

  Thus, even if the flexspline 6 expands or narrows and tilts in the vicinity of the ellipse major axis of the holding member, the flex ring 5 follows the tilt by engagement of the arc concave surface 5g and the arc convex surface 16b. Tilts. For this reason, the contact area of the flexspline 6 and the flex ring 5 increases.

  Therefore, the wave gear reducer can improve the radial rigidity of the flex spline 6 at the meshing portion between the external teeth of the flex spline 6 and the internal teeth of the circular spline 7 and increase the torsional rigidity on the output shaft side. it can.

  Alternatively, an arc concave surface may be formed on the outer peripheral roller 16 and an arc convex surface may be formed on the flex ring 5. That is, an arc concave surface may be formed on one of the outer peripheral roller 16 and the flex ring 5 and an arc convex surface may be formed on the other.

  Further, the flex ring 5 of FIGS. 7 to 10 is formed with a groove 5a along which the outer ring of the bearings 3A and 4A engages along the circumferential direction of the inner periphery.

  FIG. 12 is a cross-sectional view taken along the input shaft and the output shaft of a wave gear reducer 290 of another embodiment, which is different in configuration from the wave gear reducer 190 of the embodiment of FIGS.

  The wave gear reducer 290 shown in FIG. 12 is different in the structure of the flex spline 206 and the circular spline 207 from the wave gear reducer 190 shown in FIG. Hereinafter, only different structures will be described, and portions having the same structure are denoted by the same reference numerals as those in FIG.

  The flex spline 206 is formed in a hollow cylinder that can be elastically deformed, and is attached to the main planetary roller 3 and the auxiliary planetary roller 4, and an external gear 206 a is formed on the outer periphery.

  The fixed circular spline 207A is fixed to the first divided frame 8A. An internal gear 207Aa as a first internal gear that meshes with the external gear 206a of the flexspline 206 is formed on the inner periphery of the fixed circular spline 207A. The number of teeth of the internal gear 207Aa of the fixed circular spline 207A is 2n more than the number of teeth of the external gear 206a of the flexspline 206 (n is a positive integer). The internal gear 207Aa meshes with the external gear 206a of the flex spline 206 that is elastically deformed into an ellipse by the main planetary roller 3, the auxiliary planetary roller 4, and the flex ring 5, and the main planetary roller 3 near the major axis of the ellipse. ing.

  The output circular spline 207B is attached to the output shaft 13 and rotates integrally with the output shaft 13. An internal gear 207Ba as a second internal gear that meshes with the external gear 206a of the flex spline 206 is formed on the inner periphery of the output circular spline 207B. The number of teeth of the internal gear 207Ba of the output circular spline 207B is the same as the number of teeth of the external gear 206a of the flexspline 206. That is, the number of teeth of the internal gear 207Aa of the fixed circular spline 207A is 2n more (n is a positive integer) than the number of teeth of the internal gear 207Ba of the output circular spline 207B. As described above, the fixed circular spline 207A is formed by coaxially arranging the internal gear 207Aa and the internal gear 207Ba. The internal gear 207Ba is formed to have 2n fewer teeth than the internal gear 207Ba and transmits rotation to the output shaft.

  A flex ring 5 is interposed between the outer circumference of the main planetary roller 3 and the auxiliary planetary roller 4 and the flexspline 206.

  The operation of the wave gear reducer 290 will be described.

  The holding member 1 connected to the input shaft 11 rotates about the revolution axis 9. Then, six convenient rollers of the main planetary roller 3 and the auxiliary planetary roller 4 arranged around the holding member 1 rotate and roll while revolving on the inner peripheral surface of the flex ring 5. Due to the movement of the main planetary roller 3, the ellipse major axis position of the outer flex ring 5 and the flex spline 206 also moves while being elastically deformed. For this reason, the positions of the two positions where the external gear 206a of the flexspline 206 and the internal gear 207Aa of the fixed circular spline 207A are also moved. With this movement of the meshing position, every time the holding member 1 rotates, the flex spline 206 rotates at a reduced speed by a difference in the number of teeth from the fixed circular spline 207A. The reduced speed rotation of the flexspline 206 is transmitted to the output shaft 13 via the output circular spline 207B.

  In this way, the flex ring 5 and the flex spline 206 are arranged so as to slide in the circumferential direction so that they are elliptically deformed as compared with the case where the thickness of the flex spline 206 is increased by the thickness of the flex ring 5. The maximum stress during the process can be relaxed. Therefore, both the flex ring 5 and the flex spline 206 can be elastically deformed into an ellipse. On the other hand, the flex ring 5 has an elliptical shape along the curvature of the main planetary roller 3 when a radial and inward radial load is applied to the flexspline 206 near the circumferential direction of the main planetary roller 3. It acts to suppress bending inward. That is, it is possible to prevent bending as shown by the broken line in FIG. Thereby, it is possible to prevent the number of meshing teeth between the external gear 206a of the flexspline 206 and the internal gear 207Aa of the fixed circular spline 207A from decreasing.

  Therefore, the wave gear reducer 290 can receive the torque of the output shaft 13 in a state where the number of meshing teeth between the external gear 206a of the flexspline 206 and the internal gear 207Aa of the fixed circular spline 207A is larger than that in the conventional art. it can. For this reason, the torsional rigidity of the output shaft 13 can be increased.

  As a result, the present invention can provide a wave gear reducer having a high torsional rigidity while maintaining an inexpensive configuration using planetary rollers.

  Also in the wave gear reducer 290 described above, a groove may be formed along the circumferential direction of the inner periphery of the flex ring as shown in FIG. 4, and the planetary roller may enter the groove.

  Further, as shown in FIGS. 5 and 6, a ring-shaped outer peripheral roller is mounted on the outer periphery of the planetary roller, and grooves and protrusions that engage with each other in the circumferential direction of the outer periphery of the outer peripheral roller and the inner periphery of the flex ring. A strip may be formed. Furthermore, as shown in FIG. 7, you may form the recessed part which hold | maintains a lubrication agent in the outer periphery of a flex ring.

  3: main planetary roller, 3A: bearing, 4: auxiliary planetary roller, 5: flex ring, 5a: groove, 5b: protrusion, 5c: groove, 5d: groove, 5e: arc surface, 5f: taper part, 5g: Arc concave surface, 6: flex spline, 6a: external gear, 7: circular spline, 7a: internal gear, 11: input shaft, 13: output shaft, 17: wave generator, 190: wave gear reducer, 206: flex Spline, 206a: external gear, 207A: fixed circular spline, 207: circular spline, 207Aa: internal gear (first internal gear), 207B: output circular spline, 207Ba: internal gear (second internal gear) Gear), 290: Wave gear reducer.

Claims (9)

By rotating the input shaft, the two planetary rollers rotate while revolving inside the ring-shaped external gear meshing with the internal gear, elastically deforming the external gear into an oval shape, A wave gear reducer that reduces and transmits rotation of the input shaft to an output shaft connected to one of the external gear and the internal gear by changing the meshing position of the external gear with two locations. In
A flex ring elastically deformable between the external gear and the planetary roller,
A wave gear reducer characterized by that. A groove is formed along the circumferential direction of the inner periphery of the flex ring, and the planetary roller enters the groove.
The wave gear reducer according to claim 1. A ring-shaped outer peripheral roller is mounted on the outer periphery of the planetary roller, and grooves and ridges that engage with each other are formed in the circumferential direction of the outer periphery of the outer peripheral roller and the inner periphery of the flex ring.
The wave gear reducer according to claim 1. A recess for holding a lubricant is formed on the outer periphery of the flex ring,
The wave gear reducer according to claim 1 or 2, characterized in that The external gear is provided on the outer periphery of the other end portion of the elastically deformable cylindrical member having one end portion provided on the output shaft,
A mid-high arc surface is formed between the outer periphery of the flex ring and the inner periphery of the cylindrical member, and the flex ring and the inner periphery of the cylindrical member are in contact with each other via the arc surface. doing,
The wave gear reducer according to claim 1 or 2, characterized in that The external gear is provided on the outer periphery of the other end portion of the elastically deformable cylindrical member having one end portion provided on the output shaft,
The outer periphery of the flex ring is formed in a tapered shape that is reduced in diameter toward the output shaft, and the tapered portion is in contact with the inner periphery of the cylindrical member.
The wave gear reducer according to claim 1 or 2, characterized in that The external gear is provided on the outer periphery of the other end portion of the elastically deformable cylindrical member having one end portion provided on the output shaft,
A resin member is interposed between the outer periphery of the flex ring and the inner periphery of the cylindrical member.
The wave gear reducer according to claim 1 or 2, characterized in that The external gear is provided on the outer periphery of the other end of the elastically deformable cylindrical member having one end provided on the output shaft;
A ring-shaped outer peripheral roller is mounted on the outer periphery of the planetary roller, and an arc convex surface is formed on one of the axial direction of the outer periphery of the outer peripheral roller and the inner peripheral axis of the flex ring, and the other is related to the arc convex surface. A concave arc surface is formed,
The wave gear reducer according to claim 1. The internal gear includes a first internal gear and a first internal gear arranged in parallel with the first internal gear and connected to the output shaft by 2n fewer teeth than the first internal gear. 2 internal gears,
By changing the two meshing positions with the external gear, the rotation of the input shaft is transmitted to the output shaft at reduced speed,
The wave gear reducer according to any one of claims 1 to 4, wherein the wave gear reducer is characterized.

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