JP5179978B2 - Reduction gear - Google Patents

Description

  The present invention relates to a reduction gear used for industrial robots, automotive auxiliary machines, and the like.

  As a small reduction gear used in industrial robots and automotive accessories, an input shaft with an eccentric disk and a plurality of rollers that are in rolling contact with the outer diameter surface of the eccentric disk are held at equal pitches in the circumferential direction. An output shaft having an annular cage portion provided with a pocket and an internal gear in which a plurality of cam crests to which these rollers roll and contact are formed at equal pitches in the circumferential direction of the inner diameter surface are arranged on the same axis, When the number of rollers is less than the number of cam ridges and the shape of the cam ridge is rotated, the roller held in the pocket revolves along the outer diameter surface of the eccentric disk when the input shaft is rotated. There has been proposed a speed reducer that matches the outer diameter side envelope and outputs the revolution of the roller held in the pocket as the rotation of the output shaft (see, for example, Patent Document 1).

  In the speed reduction device described in Patent Document 1, the number of rollers is one less than the number of cam peaks, the output shaft rotates in the opposite direction to the input shaft, and when the input shaft makes one rotation, the rollers Revolution by one pitch provides a reduction ratio equal to the number of rollers.

JP-B-2-28027

  The speed reduction device described in Patent Document 1 can obtain a medium speed reduction ratio of about 10 to 50, which is required for industrial robots and automotive auxiliary machines, and can increase rigidity. Since it is necessary to arrange | position on a coaxial center so that an axis | shaft may be faced, an axial direction dimension becomes large, and there exists a problem that installation is difficult in the site | part to which an axial direction dimension is restrained small.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a reduction gear which can obtain a medium reduction ratio of about 10 to 50 with high rigidity and can be designed with a compact axial dimension.

  In order to solve the above-described problems, the speed reducer of the present invention includes an input shaft having a cylindrical inner surface that is eccentric to the cylindrical portion, and an annular shape that includes a pocket that holds a plurality of rollers that are in rolling contact with the eccentric cylindrical inner surface. An output shaft having a cage portion, and a base shaft formed by equidistantly forming a plurality of cam ridges in contact with a roller held in the pocket in the circumferential direction of the outer diameter surface, and The roller is held at a position where the number of dividing points when the cage portion is divided at equal pitches in the circumferential direction is different from the number of the cam crests by one or all of the divided points. The inner diameter side envelope of the locus in which the roller held in the pocket revolves along the eccentric cylindrical inner surface when the input shaft is rotated. Align with the line, and The revolution of the roller held in Tsu bets adopted a configuration in which the output as the rotation of the output shaft.

  In other words, an eccentric cylindrical inner diameter surface is provided in the cylindrical portion of the input shaft, and the same coaxial is formed between the cam ridges formed at an equal pitch in the circumferential direction of the outer diameter surface of the base shaft disposed coaxially on the inner diameter side. The roller held in the pocket of the holder part of the output shaft arranged on the center is brought into rolling contact, and the number of dividing points when the annular holder part is divided at equal pitches in the circumferential direction is A pocket for holding the roller is provided at all or a part of the dividing points that differ from the number by one, and the shape of one pitch of the cam crest is held in the pocket when the input shaft is rotated. By matching the inner envelope of the trajectory of the roller that revolves along the eccentric cylindrical inner surface, the rotation of the roller held in the cage pocket is output as the rotation of the output shaft. A medium reduction ratio of about 10-50 is obtained. The axial dimension compactly and to be able to design.

  A pocket for holding the roller of the cage part is provided at a position where a part of the dividing point is thinned out, and by making the thinning interval uniform in the circumferential direction, the rotation balance of the output shaft is kept well, The number of pockets and the number of rollers can be reduced.

  By providing a gear to which rotational force is input on the outer diameter surface of the input shaft, a rotational drive source such as a motor can be arranged on the outer diameter side of the input shaft, and the axial dimension can be designed more compactly. it can.

  The output shaft can be rotated in the same direction as the input shaft by increasing the number of dividing points of the cage part by one more than the number of the cam crests. When the number of division points is one more than the number of cam crests, as shown in FIG. 2 later, the input shaft 1 rotates clockwise, and an eccentric cylindrical inner diameter surface and cam crest 4a are formed. Assuming that the maximum portion A of the annular space with the outer diameter surface of the base shaft 4 is at a position of 0 ° (12 o'clock) clockwise and the minimum portion B is at a position of 180 ° (6 o'clock), the input shaft 1 is rotated. Accordingly, the maximum portion A and the minimum portion B move clockwise, and the right half of the annular space tends to be widened and the left half of the annular space tends to be narrowed. For this reason, the roller 2 existing in the right half of the annular space moves in the outer diameter direction going up the cam peak 4a, and the roller 2 existing in the left half of the annular space moves in the inner diameter direction going down the cam peak 4a. As shown, the retainer portion 3 b of the output shaft 3 that holds the roller 2 rotates in the same clockwise direction as the input shaft 1.

  When the number of division points is reduced by one less than the number of cam peaks, the rotation direction of the input shaft 1 and the positions of the maximum portion A and the minimum portion B of the annular space are shown in FIG. 2, similarly, the roller 2 existing in the right half of the annular space moves in the outer diameter direction above the cam peak 4 a, and the roller 2 existing in the left half of the annular space sets the cam peak 4 a. In this case, as indicated by an arrow in the figure, the cage portion 3b of the output shaft 3 that holds the roller 2 rotates counterclockwise opposite to the input shaft 1.

  By making the base shaft rotatable in both directions, the reduction ratio can be increased or decreased by rotating the base shaft. That is, when the number of dividing points of the cage portion is increased by one more than the number of cam peaks, the revolution angle for one pitch of the cam peaks of the roller is increased by rotating the base shaft in the same direction as the input shaft. As a result, the reduction ratio becomes smaller, and when the roller is rotated in the opposite direction, the revolution angle for one pitch of the cam crest of the roller becomes smaller and the reduction ratio becomes larger. If the number of division points is one less than the number of cam peaks, conversely, if the base shaft is rotated in the same direction as the input shaft, the reduction ratio will increase, and if it is rotated in the reverse direction, the reduction ratio will be reduced. Get smaller.

  By forming the cylindrical inner diameter surface of the input shaft with the inner diameter surface of the inner ring of the rolling bearing fitted in the cylindrical portion, slip between the roller and the cylindrical inner diameter surface is reduced, and the input shaft and the output shaft are made smooth. Can be rotated.

  By using the roller bearing as a needle roller bearing, the radial dimension can be designed to be compact.

  By providing a means for compressing the outer ring of the rolling bearing in the axial direction, the outer ring is elastically deformed so that the inner diameter of the outer ring is reduced, and the radial direction of the rolling bearing is suppressed. Can be reduced.

  By forming the longitudinal section of the outer ring of the rolling bearing into a crank shape, it can be easily elastically deformed so that the inner diameter of the outer ring is reduced.

  Two pockets adjacent to each other in the circumferential direction of the cage portion are merged, two rollers are held at both ends in the circumferential direction of the merged pocket, and the two rollers are circumferentially moved. By providing an elastic member that urges in the direction of separating at, the rotational direction of the reduction gear can be reduced and the pocket can be easily processed.

  The outer diameter portion in which the camshaft of the base shaft is formed is divided in the axial direction, and one of the divided outer diameter portions is used as a separate cam crest member, and is elastic in the axial direction between the other divided outer diameter portion. By interposing a member and providing a phase difference between the cam crest of the cam crest member and the cam crest of the other outer diameter portion, the roller is sandwiched between two cam crests having a phase difference, The rotational direction of the speed reducer can be reduced.

  The speed reducer according to the present invention is provided with an eccentric cylindrical inner surface on the cylindrical portion of the input shaft, and a cam crest formed at an equal pitch in the circumferential direction of the outer surface of the base shaft coaxially disposed on the inner diameter side. The number of division points when the roller held in the pocket of the output shaft retainer portion, which is also arranged on the same coaxial axis, is brought into rolling contact with the annular retainer portion and divided at equal pitches in the circumferential direction. However, when the pockets that hold the rollers are provided at all or part of the dividing points that differ by 1 from the number of cam ridges, and the input shaft is rotated to the shape of one pitch of the cam ridges The roller held in the pocket matches the inner envelope of the locus on which the roller revolves along the eccentric cylindrical inner surface, and the revolution of the roller held in the pocket of the cage part is output as the rotation of the output shaft. Because it was so, with a large rigidity of about 10-50 Speed ratio is obtained, it is possible to design the axial dimension compact.

  A pocket for holding the roller of the cage part is provided at a position where a part of the dividing point is thinned out, and this thinning interval is made uniform in the circumferential direction, so that the rotation balance of the output shaft is kept well, and the pocket The number of machining and the number of rollers can be reduced.

  By providing a gear to which rotational force is input on the outer diameter surface of the input shaft, a rotational drive source such as a motor can be arranged on the outer diameter side of the input shaft, and the axial dimension can be designed more compactly. it can.

  The output shaft can be rotated in the same direction as the input shaft by increasing the number of division points of the cage part by one more than the number of cam peaks.

  By making the base shaft rotatable in both directions, the reduction ratio can be increased or decreased by rotating the base shaft.

  By forming the cylindrical inner diameter surface of the input shaft with the inner diameter surface of the inner ring of the rolling bearing fitted in the cylindrical portion, slipping between the roller and the inner diameter surface of the cylinder is reduced, and the input shaft and the output shaft rotate smoothly. Can be made.

  By using the roller bearing as a needle roller bearing, the radial dimension can be designed to be compact.

  By providing a means for compressing the outer ring of the rolling bearing in the axial direction, the outer ring is elastically deformed so that the inner diameter of the outer ring is reduced, and the radial direction of the rolling bearing is suppressed. Can be reduced.

  By forming the longitudinal section of the outer ring of the rolling bearing into a crank shape, it can be easily elastically deformed so that the inner diameter of the outer ring is reduced.

  Two pockets adjacent to each other in the circumferential direction of the cage portion are merged, two rollers are held at both ends of the merged pocket in the circumferential direction, and the two rollers are circumferentially aligned. By providing the elastic member that urges in the separating direction, the rotational direction of the reduction gear can be reduced and the pocket can be easily processed.

  The outer diameter portion of the base shaft forming the cam crest is divided in the axial direction, one divided outer diameter portion is a separate cam crest member, and the other outer diameter portion is divided in the axial direction. By interposing an elastic member and providing a phase difference between the cam crest of this cam crest member and the cam crest of the other outer diameter portion, the roller is sandwiched between two cam crests having a phase difference, The rotational direction of the speed reducer can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment. The speed reducer includes an input shaft 1 having a cylindrical portion 1a with an eccentric inner surface, an output shaft 3 having an annular retainer portion 3b provided with pockets 3a for holding a plurality of rollers 2, and a plurality of cam peaks 4a. Of the inner ring 5b of the needle roller bearing 5 in which the outer ring 5a is fitted on the inner diameter surface of the eccentric cylindrical portion 1a. The roller 2 held in each pocket 3a is brought into rolling contact with the cam crest 4a of the inner diameter surface and the outer diameter surface of the base shaft 4, and when the cage portion 3b is divided at a constant pitch in the circumferential direction. Pockets 3a for holding the rollers 2 are provided at all positions of the dividing points where the number N of dividing points is one more than the number of cam peaks 4a, and the shape of one pitch of the cam peaks 4a is input. An inner ring in which the roller 2 held in the pocket 3a is eccentric when the shaft 1 is rotated. The locus inner diameter side envelope of which revolves along the cylindrical inner diameter surface of b is adapted to match. In this embodiment, the number of pockets 3a and rollers 2, that is, the number N of division points is 15, and the number of cam peaks 4a is 14.

  The input shaft 1 and the output shaft 3 are supported on the base shaft 4 by ball bearings 6a and 6b, respectively, and a gear 7 to which rotational force is input from a driving source such as a motor is provided on the outer diameter surface of the input shaft 1. ing. Further, the base shaft 4 is rotatable in both directions, and the reduction ratio of the input shaft 1 and the output shaft 3 can be increased or decreased by rotating the base shaft 4 as will be described later.

  Below, the deceleration mechanism of the speed reducer mentioned above is demonstrated. As shown in FIG. 2, the input shaft 1 rotates clockwise, and the maximum portion A of the annular space between the cylindrical inner surface of the eccentric inner ring 5b and the outer surface of the base shaft 4 on which the cam ridge 4a is formed is a clock. Assuming that the position of 0 ° and the minimum portion B are 180 ° around, the maximum portion A and the minimum portion B move clockwise as the input shaft 1 rotates, and the right half of the annular space is wide. The left half of the annular space tends to become narrower. For this reason, the roller 2 existing in the right half of the annular space moves in the outer diameter direction going up the cam peak 4a, and the roller 2 existing in the left half of the annular space moves in the inner diameter direction going down the cam peak 4a. As shown, the retainer portion 3 b of the output shaft 3 that holds the roller 2 rotates in the same clockwise direction as the input shaft 1.

  In this embodiment, since the number N of the dividing points of the cage portion 3b is one more than the number of the cam peaks 4a, each roller 2 rotates clockwise by one pitch of the cam peaks 4a when the input shaft 1 rotates once. The speed reduction ratio between the input shaft 1 and the output shaft 3 is equal to the number N of division points.

  FIG. 3 shows a modification of the first embodiment. In this modification, the number N of division points of the cage portion 3b is 15, the number of cam peaks 4a is 16, and the number N of division points is one less than the number of cam peaks 4a. As in the first embodiment, pockets 3a for holding the rollers 2 are provided at all dividing points. As in FIG. 2, the input shaft 1 rotates clockwise, and the maximum portion A of the annular space between the cylindrical inner surface of the eccentric inner ring 5b and the outer surface of the base shaft 4 on which the cam ridge 4a is formed is clockwise. Assuming that the position of 0 ° and the minimum portion B are at the position of 180 °, the right half of the annular space tends to be widened, the left half of the annular space tends to be narrowed, and the roller 2 existing in the right half of the annular space is The roller 2 existing in the left half of the annular space moves in the outer diameter direction going up the cam peak 4a and moves in the inner diameter direction going down the cam peak 4a. In this modification, the roller 2 is held as shown by the arrows in the figure. The retainer portion 3b of the output shaft 3 that rotates rotates counterclockwise opposite to that of the input shaft 1.

  When the base shaft 4 is rotated in the same clockwise direction as the input shaft 1, in the case of FIG. 2 in which the number of pockets 3a is larger than the number of cam peaks 4a, the revolution angle of the roller 2 with respect to one pitch of the cam peaks 4a is increased. In the case of FIG. 3 in which the reduction ratio becomes smaller and the number N of division points is reduced by one than the number of cam peaks 4a, the revolution angle of the roller 2 with respect to one pitch of the cam peaks 4a becomes smaller. Reduction ratio increases. Further, when the base shaft 4 is rotated counterclockwise opposite to the input shaft 1, the speed reduction ratio increases in the case of FIG. 2, and the speed reduction ratio decreases in the case of FIG.

  FIG. 4 shows a second embodiment. This speed reduction device has the same basic configuration as that of the first embodiment, and is thinned out every second part of the dividing points of the cage part 3b where the number N of the dividing points is 15. The difference is that pockets 3a for holding the rollers 2 are provided at five locations at equal intervals in the circumferential direction. The other parts are the same, and the deceleration characteristics are the same as those in the first embodiment.

  In the second embodiment described above, the number of division points N (= 15) is divided by 3 which is a divisor, and the pockets of the cage portion are provided at five locations at equal thinning intervals. It can also be provided in three places by dividing by 5 which is a divisor. Even when the number N of division points is another number, the pockets of the cage portion may be provided at equal thinning intervals at the number of places divided by the divisor.

  FIG. 5 shows a third embodiment. The basic structure of this reduction gear is also the same as that of the first embodiment. Two adjacent pockets 3a of the retainer portion 3b of the output shaft 3 are combined, and the combined pockets are combined. The difference is that the two rollers 2 held at both ends in the circumferential direction 3a are urged away by springs 8 as elastic bodies. In this embodiment, the backlash in the circumferential direction of the roller 2 in the pocket 3a is eliminated, and the backlash in the circumferential direction of the reduction gear can be reduced. Further, the processing of the pocket 3a can be facilitated. In this embodiment, the number of pockets before merging is 14 and the number of cam peaks 4a is 13, and when the number of pockets before merging is an odd number, only one extra pocket is independently created. It may be formed.

  FIG. 6 shows a fourth embodiment. The basic structure of this reduction gear is the same as that of the first embodiment, and the outer ring 5a of the needle roller bearing 5 fitted into the cylindrical portion 1a of the input shaft 1 is connected to the end of the cylindrical portion 1a. It differs in that it is compressed in the axial direction by a nut 9 screwed into the part, and its longitudinal cross section has a crank shape. In this embodiment, the outer ring 5a is elastically deformed so that the inner diameter thereof is reduced, the radial direction of the needle roller bearing 5 is suppressed, and the circumferential direction of the reduction gear is reduced.

  7 and 8 show a fifth embodiment. The basic structure of this reduction gear is the same as that of the first embodiment. The outer diameter portion of the base shaft 4 provided with the cam ridges 4a is divided in the axial direction, and the separated cam ridges are divided. The member 10a is abutted against the other integral outer diameter portion 10b with a rubber ring 11 as an elastic member interposed therebetween in the axial direction, and the cam mountain 4a of the cam mountain member 10a and the cam mountain 4a of the integral outer diameter portion 10b The difference is that a small phase difference is provided between the two. In this embodiment, the roller 2 is sandwiched between two cam ridges 4a having a phase difference, so that the play in the circumferential direction of the reduction gear can be reduced.

  9 and 10 show a modification of the fifth embodiment. In this modification, circular grooves 12 extending in the circumferential direction are provided on the opposed surfaces of the divided separate cam crest members 10 a and the integrated outer diameter portion 10 b, and the coil springs 13 are accommodated in these circular grooves 12. Then, a phase difference is provided between the cam crest 4a of the cam crest member 10a and the cam crest 4a of the integral outer diameter portion 10b, and the restoring force of the coil spring 13 causes the roller 2 to have two cam crests 4a having a phase difference. It is trying to pinch with. In addition, you may provide each circular groove | channel 12 which accommodates the coil spring 13 in the multiple places of the circumferential direction.

The longitudinal cross-sectional view which shows the reduction gear of 1st Embodiment Sectional view along the line II-II in FIG. Sectional drawing which shows the modification of FIG. The cross-sectional view of the principal part showing the reduction gear of the second embodiment Cross section of the principal part which shows the reduction gear device of 3rd Embodiment Longitudinal sectional view showing a reduction gear according to a fourth embodiment A longitudinal sectional view showing a reduction gear device according to a fifth embodiment Sectional drawing which expands and shows the principal part of FIG. FIG. 7 is a longitudinal sectional view showing a modification of FIG. Sectional view along line XX in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 1a Cylinder part 2 Roller 3 Output shaft 3a Pocket 3b Cage part 4 Base shaft 4a Cam crest 5 Needle roller bearing 5a Outer ring 5b Inner ring 6a, 6b Ball bearing 7 Gear 8 Spring 9 Nut 10a Cam crest member 10b Integrated outer diameter Part 11 Rubber ring 12 Arc groove 13 Coil spring

Claims (11)

  An input shaft having a cylindrical inner diameter surface eccentric to the cylindrical portion, an output shaft having an annular retainer portion provided with a pocket for holding a plurality of rollers in rolling contact with the eccentric cylindrical inner diameter surface, and held in the pocket When a plurality of cam crests with which the roller rolls are arranged on the same axis with a base shaft formed at an equal pitch in the circumferential direction of the outer diameter surface, the annular cage portion is divided at an equal pitch in the circumferential direction. A pocket for holding the roller is provided at a position where all or some of the dividing points differ from the number of the cam peaks by one, and a shape corresponding to one pitch of the cam peaks is formed. When the input shaft is rotated, the roller held in the pocket is held in the pocket of the cage portion so as to match the inner diameter side envelope of the locus revolving along the eccentric cylindrical inner diameter surface. The rotation of the output roller, Reduction apparatus designed to output as rolling.   The speed reducer according to claim 1, wherein a pocket for holding the roller of the cage part is provided at a position where a part of the dividing point is thinned out, and the thinning interval is made uniform in the circumferential direction.   The speed reducer according to claim 1 or 2, wherein a gear to which a rotational force is input is provided on an outer diameter surface of the input shaft.   The speed reducer according to any one of claims 1 to 3, wherein the number of dividing points of the cage portion is increased by one more than the number of the cam peaks.   The speed reducer according to any one of claims 1 to 4, wherein the base shaft is rotatable in both directions.   The reduction gear according to any one of claims 1 to 5, wherein a cylindrical inner diameter surface of the input shaft is formed by an inner diameter surface of an inner ring of a rolling bearing fitted in the cylindrical portion.   The speed reducer according to claim 6, wherein the rolling bearing is a needle roller bearing.   The speed reducer according to claim 6 or 7, further comprising means for compressing an outer ring of the rolling bearing in an axial direction.   The speed reducer according to claim 8, wherein a longitudinal section of the outer ring of the rolling bearing is formed in a crank shape.   Two pockets adjacent to each other in the circumferential direction of the cage portion are merged, two rollers are held at both ends in the circumferential direction of the merged pocket, and the two rollers are circumferentially moved. The speed reducer according to claim 1, further comprising an elastic member that is urged in a direction in which the elastic member is separated.   The outer diameter portion in which the camshaft of the base shaft is formed is divided in the axial direction, and one of the divided outer diameter portions is used as a separate cam crest member, and is elastic in the axial direction between the other divided outer diameter portion. The speed reducer according to any one of claims 1 to 10, wherein a phase difference is provided between a cam crest of the cam crest member and a cam crest of the other outer diameter portion with a member interposed therebetween.

Images