WO2010004843A1

WO2010004843A1 - Reduction device

Info

Publication number: WO2010004843A1
Application number: PCT/JP2009/061099
Authority: WO
Inventors: 幸治秋吉; 隆英齋藤; 義主寺田
Original assignee: Ntn株式会社
Priority date: 2008-07-08
Filing date: 2009-06-18
Publication date: 2010-01-14

Abstract

A reduction device having high rigidity, capable of providing an intermediate reduction ratio in the range from 10 to 50, and having a reduced axial dimension and a reduced outer diameter dimension. The reduction device has coaxially mounted thereto an input shaft (1) having an eccentric cylindrical inner diameter surface on a cylindrical section (1a) thereof, an output shaft (3) having an annular retainer section (3a) in which pockets (2a) for holding rollers (2), which make rolling contact with the eccentric cylindrical inner diameter surface, are formed, and a base shaft (4) having cam crest (4a), with which the rollers (2) make rolling contact, formed at equal intervals on the outer diameter surface of the base shaft (4). The pockets (2a) are formed in the retainer section (3a) at the positions of split points the number of which is determined by circumferentially equally dividing the retainer section and which is different by one from the number of the cam crests. The shape of the cam crest (4a) for one pitch is aligned with the inner diameter-side envelope of a path on which the rollers (2) held in the pockets (2a) revolve along the cylindrical inner diameter surface of an inner ring (5b) when the input shaft (1) is rotated. The revolution of the rollers (2) held in the pockets (2a) of the retainer section (3a) is outputted as the rotation of the output shaft (3).

Description

Reduction gear

The present invention relates to a reduction gear used for industrial robots, automobile 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. In addition, when the torque is transmitted, a tensile stress is generated in the circumferential direction on the internal gear, and there is a steep wall thickness variation by the number of cam ridges in the circumferential direction of the internal gear, so stress concentration occurs in many thin portions. Cheap. For this reason, since it is necessary to set the thickness of the internal gear to be sufficiently thick, there is a problem that the outer diameter is increased and the compact design is hindered.

Therefore, an object of the present invention is to provide a reduction gear device that can obtain a medium reduction ratio of about 10 to 50 with high rigidity and that can be designed to have a compact axial dimension and outer diameter.

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. In line with the line, The revolution of the roller held in the packet, and employs a configuration for outputting a 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. With a medium reduction ratio of about 10-50 Were to be designed the axial dimension compact.

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 cam peaks. 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 a 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 3a 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.

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.

Further, the speed reducer of the present invention includes an input shaft having a cylindrical inner surface eccentric to the cylindrical portion, an output shaft having a plurality of cam ridges formed at equal pitches on the outer diameter surface, and an eccentric cylindrical inner surface of the input shaft. And an intermediate shaft having an annular retainer portion provided with a pocket for holding a plurality of rollers that are in rolling contact with the outer diameter surface of the output shaft formed with a cam crest, and arranged on the same axis, the annular retainer A pocket for holding the roller at a position where the number of dividing points when the part is divided at equal pitches in the circumferential direction is different from the number of the cam crests by all or part of the dividing points. And the shape of one pitch of the cam crest is configured such that the roller held in the pocket circumscribes when the input shaft is rotated and the output shaft rotates by one pitch of the cam crest. The configuration was also adopted.

In other words, the cylindrical part of the input shaft is provided with an eccentric cylindrical inner diameter surface, and a cam crest is formed on the outer diameter surface of the output shaft arranged on the inner diameter side, which is held in the pocket of the cage part of the intermediate shaft. All the positions or parts of the dividing points where the number of dividing points differs by one from the number of cam crests when the annular retainer part is divided at equal pitches in the circumferential direction. A pocket for holding the roller is provided in the thinned position, and the shape of one pitch of the cam peak is held in the pocket when the input shaft is rotated and the output shaft rotates by one pitch of the cam peak. By adopting a shape that circumscribes the roller, it is possible to obtain a moderate reduction ratio of about 10 to 50 with a large rigidity, assuming that the outer ring has a gentle wall thickness fluctuation of only one cycle due to eccentricity in the circumferential direction, and the outer diameter dimension. Can be designed compactly.

By reducing the number of division points of the cage part by one less than the number of cam ridges, the output shaft of the reduction gear at each stage can be rotated in the same direction as the input shaft. When the number of division points is one less than the number of cam crests, as shown in FIG. 12 later, the input shaft 11 rotates clockwise to form an eccentric cylindrical inner surface and cam crest 13a. Assuming that the maximum portion A of the annular space with the outer diameter surface of the output shaft 13 is at a position of 0 ° (12 o'clock) in the clockwise direction and the minimum portion B is at a position of 180 ° (6 o'clock), the rotation of the input shaft 11 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 12 existing in the right half of the annular space moves relative to the outer diameter direction going up the cam peak 13a, and the roller 12 existing in the left half of the annular space moves relative to the inner diameter direction going down the cam peak 13a. As indicated by the arrow, the output shaft 13 rotates in the same clockwise direction as the input shaft 11.

When the number of division points is increased by one more than the number of cam peaks, the rotational direction of the input shaft 11 and the positions of the maximum portion A and the minimum portion B of the annular space are set as shown in FIG. If the same setting as in FIG. 12 is used, similarly, the roller 12 present in the right half of the annular space moves in the outer diameter direction up the cam peak 13a, and the roller 12 present in the left half of the annular space descends the cam peak 13a. In this case, the output shaft 13 rotates counterclockwise opposite to the input shaft 11 as indicated by an arrow in the figure.

The reduction gears are arranged in a plurality of stages in series in the axial direction, and a cylinder portion having the eccentric cylindrical inner surface is provided on the output end side of the output shaft of the adjacent front reduction gear, and the subsequent reduction gear By using this input shaft, the reduction ratio can be easily increased.

By applying a phase difference between the pockets of the intermediate shaft of the adjacent front-stage speed reducer and the subsequent-stage speed reducer, and energizing these intermediate shafts to rotate in the opposite directions, the output shaft of the front stage It is possible to eliminate the rotation direction of the integral input / output shaft that becomes the input shaft of the subsequent stage, and to reduce the rotation direction of the plurality of reduction gears.

The outer diameter portion in which the cam peak of the output shaft is formed is divided in the axial direction, one divided outer diameter portion is used as a separate cam crest member, and the other outer diameter portion is divided in the axial direction. By providing an elastic 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.

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 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 compactly.

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, the outer ring 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 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 Reduction ratio is obtained, it is possible to design the axial dimension compact.

Further, the speed reducer of the present invention is provided with an eccentric cylindrical inner surface on the cylindrical portion of the input shaft, and a cam crest is formed on the outer diameter surface of the output shaft arranged on the inner diameter side of the intermediate shaft. The number of division points when the roller held in the cage pocket rolls and the annular cage part is divided at equal pitches in the circumferential direction is different from the number of cam ridges by one. When a pocket that holds the roller is provided at all or a part of the position where the roller is thinned, the shape of one pitch of the cam crest is rotated, and the input shaft is rotated to rotate the output shaft by one pitch of the cam crest In addition, since a configuration in which the roller held in the pocket is circumscribed is also adopted, a medium reduction ratio of about 10 to 50 can be obtained with high rigidity, and the outer diameter can be designed compactly.

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. A longitudinal sectional view showing a reduction gear device according to a sixth embodiment Sectional view along line XII-XII in FIG. Sectional drawing which shows the modification of FIG. Cross-sectional view showing a reduction gear according to a seventh embodiment A longitudinal sectional view showing a reduction gear device according to an eighth embodiment a and b are sectional views taken along lines XVIa-XVIa and XVIb-XVIb in FIG. A longitudinal sectional view showing a reduction gear device according to a ninth embodiment Sectional drawing which expands and shows the principal part of FIG. FIG. 17 is a longitudinal sectional view showing a modification of FIG.

Mode for carrying out the invention

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 having an eccentric inner surface, an output shaft 3 having an annular retainer portion 3a provided with pockets 2a 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 2a 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 3a is divided at a constant pitch in the circumferential direction. Pockets 2a 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 2a 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 2a and rollers 2, that is, the number N of dividing 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.

Hereinafter, the deceleration mechanism of the above-described reduction gear will be described. 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 a 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 3a is one more than the number of cam peaks 4a, when the input shaft 1 makes one rotation, each roller 2 rotates clockwise by one pitch of the cam peaks 4a. 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 3a 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 2a 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 3 a 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 2a 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 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 reducer 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 3a where the number N of dividing points is 15. The difference is that pockets 2a for holding the rollers 2 are provided at five locations at equal thinning 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 N (= 15) of the dividing points is divided by 3 which is a divisor, and the pockets 2a of the cage portion 3a are provided at five locations at equal thinning intervals. Alternatively, it can be provided at three locations by dividing by another divisor of 5. Even when the number N of division points is another number, the pockets 2a of the cage portion 3a are preferably 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, and two adjacent pockets 2a of the retainer portion 3a of the output shaft 3 are combined, and this combined pocket The difference is that the two rollers 2 held at both ends in the circumferential direction 2a 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 2a is eliminated, and the backlash in the circumferential direction of the reduction gear can be reduced. Further, the processing of the pocket 2a 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 25 as an elastic member interposed in the axial direction, and the cam crest 4a of the cam crest member 10a and the cam crest 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 26 extending in the circumferential direction are provided on the opposed surfaces of the divided separate cam crest members 10a and the integrated outer diameter portion 10b, and the coil springs 27 are accommodated in the circular grooves 26. Thus, 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 27 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 26 which accommodates the coil spring 27 in the multiple places of the circumferential direction.

FIG. 11 and FIG. 12 show a sixth embodiment. The speed reducer includes an input shaft 11 having a cylindrical portion 11a having an eccentric inner surface, an output shaft 13 having a plurality of cam ridges 13a formed on the outer surface at an equal pitch, and a pocket 12a for holding a plurality of rollers 12. The intermediate shaft 14 having the annular retainer portion 14a provided is coaxially disposed, and the cylindrical inner diameter surface of the inner ring 5b of the needle roller bearing 5 and the output shaft 13 fitted into the inner diameter surface of the eccentric cylindrical portion 11a. The roller 12 held in each pocket 12a is brought into rolling contact with the cam crest 13a of the outer diameter surface, and the number N of division points when the cage portion 14a is divided at a constant pitch in the circumferential direction. However, pockets 12a for holding the rollers 12 are provided at all positions of the dividing points that are one less than the number of cam peaks 13a, and the shape of one pitch of the cam peaks 13a causes the input shaft 11 to rotate. The output shaft 13 is 1 pin of the cam crest 13a. When rotating switch component, it has a shape roller 12 held in the pocket 12a is circumscribed. In this embodiment, the number of pockets 12a and rollers 12, that is, the number N of division points is 15, and the number of cam peaks 13a is 16. The intermediate shaft 14 is fixed with a ring portion 14b projecting outward so as to be prevented from rotating.

Hereinafter, the deceleration mechanism of the above-described reduction gear will be described. As shown in FIG. 12, the input shaft 11 rotates clockwise, and the maximum portion A of the annular space between the eccentric cylindrical inner diameter surface of the inner ring 5b and the outer diameter surface of the output shaft 13 formed with the cam ridge 13a is obtained. If the clockwise position is 0 ° and the minimum portion B is 180 °, the maximum portion A and the minimum portion B move clockwise as the input shaft 11 rotates, and the right half of the annular space is The left half of the annular space tends to become narrower. For this reason, the roller 12 existing in the right half of the annular space moves relative to the outer diameter direction going up the cam peak 13a, and the roller 12 existing in the left half of the annular space moves relative to the inner diameter direction going down the cam peak 13a. As indicated by the arrow, the output shaft 13 rotates in the same clockwise direction as the input shaft 11.

In this embodiment, since the number N of division points is one less than the number of cam peaks 13a, when the input shaft 11 rotates once, the output shaft 13 rotates clockwise by one pitch of the cam peaks 13a, and the input The reduction ratio between the shaft 11 and the output shaft 13 is equal to the number of cam peaks 13a.

FIG. 13 shows a modification of the sixth embodiment. In this modification, the number N of division points of the cage portion 14a is 15, the number of cam peaks 13a is 14, and the number N of division points is one more than the number of cam peaks 13a. As in the sixth embodiment, pockets 12a for holding the rollers 12 are provided at all dividing points. As in FIG. 12, the input shaft 11 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 output shaft 13 on which the cam ridges 13a are formed is clockwise. If the minimum portion B is at a 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 12 present in the right half of the annular space. The roller 12 present in the left half of the annular space moves relative to the outer diameter direction going up the cam crest 13a and toward the inner diameter direction going down the cam crest 13a. In this modification, as shown by the arrows in FIG. 13 rotates counterclockwise opposite to the input shaft 11.

FIG. 14 shows a seventh embodiment. This speed reducer has the same basic configuration as that of the sixth embodiment, and is thinned out at every second part of the dividing points of the cage part 14a where the number N of the dividing points is 15. The difference is that pockets 12a for holding the rollers 12 are provided at five locations at equal thinning intervals in the circumferential direction. Other parts are the same, and the deceleration characteristic is the same as that of the sixth embodiment.

15 and 16 show an eighth embodiment. In this reduction gear, the reduction gear of the sixth embodiment is arranged in two stages in series in the axial direction, and a cylindrical portion 21a having an inner diameter surface eccentric to the output end side of the output shaft 13 of the first reduction gear is provided. The needle roller bearing 5 is fitted on the inner diameter surface of the cylindrical portion 21a, and the cylindrical inner diameter surface of the inner ring 5b and the second stage output shaft are provided. The plurality of rollers 22 held in the pocket 22a of the cage portion 24a of the intermediate shaft 24 at the second stage are in contact with the cam crest 23a of the outer diameter surface 23. The

cam ridges

13a, 23a and the

pockets

12a, 22a of the first-stage and second-stage reduction gears have the same number, and the number of the

cam ridges

13a, 23a is one more than the number of the

pockets

12a, 22a. ing. Note that the number of

cam ridges

13a and 23a in the first and second stages and the number of

pockets

12a and 22a may be different from each other.

As shown in FIGS. 16A and 16B, the first and second

intermediate shafts

14 and 24 have a phase difference between the

pockets

12a and 22a of the

cage portions

14a and 24a. The intermediate shaft 14 at the stage is urged by the respective

annular portions

14b and 24b so as to twist in the clockwise direction and the second stage intermediate shaft 24 in the counterclockwise direction. Therefore, the rotation direction of the integral input / output shaft that becomes the second-stage input shaft 21 at the first-stage output shaft 13 is eliminated, and consequently the rotation direction of the two-stage reduction gear is reduced. The

17 and 18 show a ninth embodiment. This reduction gear has the same basic configuration as that of the sixth embodiment, and the outer diameter portion provided with the cam crest 13a of the output shaft 13 is divided in the axial direction. The crest member 10a is abutted against the other integral outer diameter portion 10b with a rubber ring 25 as an elastic member interposed therebetween in the axial direction, and the cam crest 13a of the cam crest member 10a and the cam crest 13a of the integral outer diameter portion 10b. Is different in that a small phase difference is provided. In this embodiment, it is possible to reduce the play in the circumferential direction of the reduction gear by sandwiching the roller 12 between two cam peaks 13a having a phase difference.

FIG. 19 shows a modification of the ninth embodiment. In this modified example, on the opposed surfaces of the divided separate cam crest members 10a and the integrated outer diameter portion 10b, as in the modified example of the fifth embodiment shown in FIG. 10, it extends in the circumferential direction. Arc grooves 26 are provided, coil springs 27 are accommodated in these arc grooves 26, and a phase difference is provided between the cam crest 13a of the cam crest member 10a and the cam crest 13a of the integral outer diameter portion 10b. Thus, the roller 12 is sandwiched between two cam peaks 13a having a phase difference.

1, 11, 21

Input shaft

1a, 11a,

21a Tube portion

2, 12, 22

Roller

2a, 12a,

22a Pocket

3, 13, 23 Output shaft

3a Cage portion

13a, 23a Cam crest 4 Base shaft 4a Cam crest 5 Needle shape 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 parts

14, 24

Intermediate shafts

14a,

24a Cage parts

14b, 24b Ring part 25 Rubber ring 26 Arc groove 27 Coil spring

Claims

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 output shaft Reduction apparatus designed to output a rotation.
The reduction gear according to claim 1, wherein a gear for inputting a rotational force is provided on an outer diameter surface of the input shaft.
The speed reducer according to claim 1 or 2, wherein the number of division points of the cage portion is increased by one more than the number of the cam peaks.
The reduction gear according to any one of claims 1 to 3, wherein the base shaft is rotatable in both directions.
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 reduction gear according to any one of claims 1 to 4, wherein a member is interposed to provide a phase difference between the cam crest of the cam crest member and the cam crest of the other outer diameter portion.
An input shaft having a cylindrical inner diameter surface eccentric to the cylindrical portion, an output shaft having a plurality of cam peaks formed on the outer diameter surface at an equal pitch, and an eccentric cylindrical inner diameter surface of the input shaft and a cam peak of the output shaft are formed. And an intermediate shaft having an annular cage portion provided with a pocket for holding a plurality of rollers that are in rolling contact with the outer diameter surface, are arranged on the same axis, and the annular cage portion is arranged at an equal pitch in the circumferential direction. A pocket for holding the roller is provided at a position where the number of dividing points when divided is different from the number of the cam crests by one or all of the positions of the dividing points, and a part of the cam crests is provided. A speed reducer in which the shape of the pitch is such that when the input shaft is rotated and the output shaft is rotated by one pitch of the cam crest, the roller held in the pocket circumscribes the roller.
The speed reducer according to claim 6, wherein the number of dividing points of the cage portion is one less than the number of cam peaks.
The reduction gears are arranged in a plurality of stages in series in the axial direction, and a cylinder portion having the eccentric cylindrical inner surface is provided on the output end side of the output shaft of the adjacent front reduction gear, and the subsequent reduction gear The speed reducer according to claim 6 or 7, wherein an input shaft is used.
The speed reducer according to claim 8, wherein a phase difference is provided between pockets of the intermediate shaft of the adjacent front speed reducer and the subsequent speed reducer, and the intermediate shafts are urged to twist counterclockwise. .
The outer diameter portion in which the cam peak of the output shaft is formed is divided in the axial direction, one divided outer diameter portion is used as a separate cam crest member, and the other outer diameter portion is divided in the axial direction. The speed reducer according to any one of claims 6 to 9, wherein an elastic member is interposed to provide a phase difference between the cam crest of the cam crest member and the cam crest of the other outer diameter portion.
The speed reducer according to any one of claims 1 to 10, wherein a pocket for holding the roller of the cage portion 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 reduction gear according to any one of claims 1 to 11, 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 reduction gear according to claim 12, wherein the rolling bearing is a needle roller bearing.
14. The reduction gear according to claim 12, further comprising means for compressing an outer ring of the rolling bearing in an axial direction.
15. The reduction gear according to claim 14, 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 any one of claims 1 to 15, further comprising an elastic member that is urged in a direction of separating at a distance.