JP2011226584A - Decelerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost of machining a roller type decelerating device.SOLUTION: An input axle 7 and an output axle 14 are coaxially arranged so that the axial ends thereof face each other, and a housing 1 covers the ends of both axles and supports an internal gear 3. Eccentric disks 9 are rotatably provided at the axial end of the input axle 7 in the internal gear 3. A cage 16 is provided at the axial end of the output axle 14, and is disposed between the internal gear 3 and bearings 13 which are pressure fitted to the outer surfaces of the eccentric disks 9. A plurality of pockets 19 are formed in the cage 16, and rollers 20 that can roll along the outer diameter surfaces of outer rings of the bearings 13 are accommodated in the pockets 19, respectively. The rotation of the input axle 7 is reduced in accordance with the number of the internal teeth 4 and is transmitted to the output axle 14. The eccentric disk 9 is separated from the input axle 7, and the eccentric disk 9 is press-fitted into the input axle 7, thereby reducing the cost as compared with a decelerating device in which the eccentric disk 9 is integrated with the input axle 7.

Description

  The present invention relates to a roller-type reduction device that engages a roller with internal teeth formed on the inner periphery of an internal gear and decelerates and transmits the rotation of an input shaft to an output shaft.

  As this type of roller speed reducer, the one described in Patent Document 1 has been conventionally known. FIG. 8 shows a roller-type speed reducer described in Patent Document 1. In this roller type speed reducer, the input shaft 30 and the output shaft 31 are arranged coaxially so that the shaft end portions face each other. An eccentric disc 34 that supports an internal gear 33 on the circumference, is provided at the shaft end of the input shaft 30 and is rotatable within the internal gear 33, and an internal gear 33 and A cage 36 disposed between the bearings 35 press-fitted into the outer diameter surface of the eccentric disk 34 is provided, and a plurality of pockets 37 are formed in the cage 36, and the outer diameter surface of the bearing 35 is formed in each of the pockets 37. The roller 38 which can roll along is accommodated.

  In the reduction gear configured as described above, when the input shaft 30 rotates, the roller 38 sequentially meshes with the internal teeth 33a of the internal gear 33 due to the rotation of the eccentric disk 34, and for each rotation of the input shaft 30, The output shaft 31 is decelerated with respect to the rotation of the input shaft 30 and rotates according to the number of teeth of the internal teeth 33a.

  In addition, in order to obtain smooth rotation transmission, the output shaft 31 is rotated by the rotation of the eccentric disc 34 so that the tooth profile of the internal teeth 33 a is within the range of the rotation angle of the output shaft 31 corresponding to one pitch of the internal gear 33. At this time, a tooth profile having one tooth corresponding to the curve outside the roller 38 among the curves parallel to the locus drawn by the center of the roller 38 is used.

JP 62-93565 A

  By the way, in the conventional roller type speed reducer, the eccentric disk 34 is provided integrally with the input shaft 30, and the outer diameter surface of the eccentric disk 34 is the press-fit surface 34a of the bearing 35. Post-processing of the surface 34a is necessary, and the press-fitting surface 34a is eccentric with respect to the input shaft 30, so that there is a problem that grinding is difficult and the processing cost is high.

  In addition, as shown in FIG. 8, when the eccentric disks 34 are provided in double rows in the axial direction of the input shaft 30, grinding becomes more difficult, and points to be improved in order to reduce the processing cost. Was left.

  An object of the present invention is to reduce the processing cost of the roller type reduction gear.

  In order to solve the above-described problems, in the present invention, a fixed housing, an internal gear supported by the housing and provided with a plurality of internal teeth on the inner periphery, and coaxial with the internal gear And an input shaft provided with an eccentric disk at an end of the shaft located inside the internal gear, a bearing supported on the outer diameter surface of the eccentric disk, and the input shaft. An output shaft provided with a cage having a closed end rotatable in the internal gear at the shaft end portion, and accommodated in a pocket formed in the cage, and can roll along the outer diameter surface of the bearing A decelerating device configured to decelerate and rotate the output shaft with respect to the rotation of the input shaft according to the number of teeth of the inner teeth per one rotation of the input shaft. The input shaft at an eccentric position relative to the center of the cylindrical outer diameter surface It is a fitted is the input shaft shaft insertion hole is formed and the separate, is of the eccentric disc adopting a configuration in which prevent rotation fitted on the input shaft.

  As described above, by making the eccentric disk separate from the input shaft, the outer diameter surface of the eccentric disk can be easily finished by centerless grinding, etc., and the processing cost can be reduced. Can do.

  Here, the rotation prevention of the eccentric disk with respect to the input shaft may be by press-fitting, or may be by fitting of a spline or serration.

  In the speed reducer according to the present invention, when the eccentric disk is formed, an eccentric disk shaped material is formed by forging or pressing, and a forming method is employed in which the outer diameter surface of the eccentric disk shaped material is ground. Compared with the case where the eccentric disk is formed by turning, the eccentric disk can be easily formed, and the processing cost can be further reduced.

  Here, the bearing provided on the outer diameter surface of the eccentric disk may be a ball bearing or a roller bearing. In the use of ball bearings, the inner ring of the ball bearing can be made unnecessary by forming a ball groove for guiding the ball on the outer diameter surface of the eccentric disc, thereby reducing the cost of the reduction gear. Can do.

  In addition, when a roller bearing is used, the inner ring of the roller bearing can be made unnecessary by forming a rolling surface that guides the roller on the cylindrical outer diameter surface of the eccentric disc, so that the cost of the speed reducer can be reduced. Can be reduced.

  As described above, in the present invention, since the eccentric disk is separated from the input shaft, the outer diameter surface of the eccentric disk can be easily finished by centerless grinding or the like. Reduction can be achieved.

A longitudinal front view showing a first embodiment of a reduction gear according to the present invention Sectional view along the line II-II in FIG. 1 is an exploded perspective view showing an input shaft, an eccentric disc, and a spacer of the speed reducer shown in FIG. Longitudinal front view showing a second embodiment of a reduction gear according to the present invention 4 is an exploded perspective view showing the input shaft, the eccentric disc, and the spacer of the speed reducer shown in FIG. Longitudinal front view showing a third embodiment of a reduction gear according to the present invention Longitudinal front view showing a fourth embodiment of a reduction gear according to the present invention Longitudinal front view showing a conventional speed reducer

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of a reduction gear device according to the present invention. As illustrated, the housing 1 has a cylindrical shape. The housing 1 is divided into two in the axial direction, and a first divided housing 1a and a second divided housing 1b are provided.

  The first divided housing 1a and the second divided housing 1b are coupled and integrated by tightening bolts (not shown), and the inner surface of the abutting side end spans the first divided housing 1a and the second divided housing 1b. A large-diameter recess 2 is formed.

  An internal gear 3 is press-fitted into the large-diameter recess 2, and a plurality of internal teeth 4 are provided on the inner periphery of the internal gear 3.

  An end plate 5 is provided at the opening end of the first divided housing 1a, and an input shaft 7 is inserted into a shaft insertion hole 6 formed in the center of the end plate 5. The input shaft 7 is rotatably supported by a bearing 8 incorporated in the shaft insertion hole 6, is arranged coaxially with the internal gear 3, and has an internal gear 3 at the end of the shaft located in the housing 1b. Two eccentric discs 9 which can be rotated inside are provided at intervals in the axial direction.

  Each of the two eccentric discs 9 has a shaft insertion hole 11 at an eccentric position with respect to the center of the cylindrical outer diameter surface 10 and is separated from the input shaft 7.

  In forming the eccentric disk 9, here, an eccentric disk element is formed by forging or pressing, and the outer diameter surface 10 of the eccentric disk element is finished by centerless grinding. You may make it form by turning.

  The two eccentric discs 9 are prevented from being rotated by press-fitting to the input shaft 7, and the flange 7 a formed at the shaft end portion of the input shaft 7, the two eccentric discs 9, and one eccentric circle. It is positioned in the axial direction by a spacer 12 incorporated between the plate 9 and the bearing 8 that supports the input shaft 7.

The two eccentric discs 9 are mounted so that the center of the cylindrical outer diameter surface is shifted by 180 ° in the circumferential direction, and a bearing 13 is press-fitted into the outer diameter surface 10. A ball bearing is employed as the bearing 13. Here, δ shown in FIG. 2 indicates the amount of eccentricity between the center O ₀ of the input shaft 7 and the center O ₁ of the cylindrical outer diameter surface of the eccentric disk 9.

  An output shaft 14 is inserted inside the second divided housing 1b. The output shaft 14 is rotatably supported by a bearing 15 incorporated in the opening end portion of the second divided housing 1b, and is arranged coaxially with the input shaft 7.

  A cage 16 is provided at the end of the output shaft 14 facing the input shaft 7, and the cage 16 is rotatable between the bearing 13 on the eccentric disc 9 and the facing portion of the internal gear 3. The cage 16 has a closed end, and a bearing 26 that receives the shaft end of the input shaft 7 is incorporated in a small-diameter hole 18 formed in the center of the closed end surface 17.

  The cage 16 is formed with a plurality of pockets 19 arranged at equal intervals in the circumferential direction in double rows, and the pockets 19 in each row are positions facing the bearings 10 attached to the two eccentric disks 9 respectively. The pockets 19 in one row and the pockets 19 in the other row are offset by a half pitch in the circumferential direction.

  The number of pockets 19 in the double row is different from the number of teeth of the internal teeth 4 formed on the inner periphery of the internal gear 3, and one roller 20 is accommodated in each pocket 19 so as to be movable in the radial direction. Yes.

  The roller 20 can mesh with the internal teeth 4 of the internal gear 3, and the internal teeth 4 with which the rollers 20 are meshed have a rotation angle of the output shaft 14 as described in Patent Document 1 described above. In the range of one pitch of the internal teeth 4 of the internal gear 3, the output shaft 14 is rotated by the rotation of the eccentric disk 9, and at that time, the center of the roller 20 is outside the roller 20 in a curve parallel to the locus drawn. The tooth profile has one curve.

  The reduction gear shown in the first embodiment has the above-described structure. When the input shaft 7 rotates, the roller 20 sequentially meshes with the internal teeth 4 of the internal gear 3 by the rotation of the eccentric disk 9, and the input shaft 7, the output shaft 14 is decelerated relative to the rotation of the input shaft 7 and rotates according to the number of teeth of the inner teeth 4.

  As shown in the first embodiment, by making the eccentric disc 9 separate from the input shaft 7, the outer diameter surface of the eccentric disc 9 can be easily finished by centerless grinding or the like. Therefore, the processing cost can be reduced.

  In the first embodiment, when the eccentric disk 9 is formed, an eccentric disk shaped material is formed by forging or pressing, and the outer diameter surface 10 of the eccentric disk shaped material is formed by centerless grinding. Since finishing is performed, the processing cost can be further reduced.

  4 and 5 show a second embodiment of the reduction gear according to the present invention. In this embodiment, the first embodiment shown in FIGS. 1 to 3 is that the eccentric disk 9 is prevented from rotating by fitting the input shaft 7 and the eccentric disk 9 with the spline 21. Is different. For this reason, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted.

  As shown in the second embodiment, the eccentric disk 9 can be securely prevented from rotating by preventing the eccentric disk 9 from rotating by fitting the spline 21. Instead of the spline 21, the eccentric disk 9 may be prevented from rotating as fitting by serration.

  FIG. 6 shows a third embodiment of the reduction gear according to the present invention. In this embodiment, a ball groove 22 for guiding the movement of the ball 13a of the bearing 13 is formed in the cylindrical outer diameter surface 10 of the eccentric disk 9, and the inner ring 13b of the bearing 13 shown in FIG. This is different from the reduction gear shown in the first embodiment. For this reason, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted.

  As described above, by forming the ball groove 22 in the cylindrical outer diameter surface 10 of the eccentric disk 9, the inner ring 13b of the bearing 13 shown in FIG. 1 can be omitted, so that the cost can be reduced. it can.

  In FIG. 1, FIG. 4 and FIG. 6, a ball bearing is adopted as the bearing 13, but the bearing 13 is not limited to a ball bearing. For example, a roller bearing may be employed. In adopting the roller bearing, as shown in the fourth embodiment of FIG. 7, a small diameter rolling surface 23 for guiding the roller 13 c of the roller bearing 13 is provided on the cylindrical outer diameter surface 10 of the eccentric disk 9. By doing so, the inner ring of the roller bearing 13 can be eliminated, and in this case as well, the cost can be reduced as in the third embodiment.

Here, the small-diameter rolling surface 23 is smaller than the outer diameter of the cylindrical outer diameter surface 10, and a guide collar 24 for the roller end surface is formed only on one side of the small-diameter rolling surface 23. 7, as shown in FIG. 7, a disc 25 having the same diameter as the cylindrical outer diameter surface 10 is provided on the other side surface of the eccentric disc 9, and a roller is formed on the inner peripheral portion of the disc 25. Guide the end face of 13c.

  In each embodiment, the input shaft 7 is provided with the two eccentric discs 9. However, the number of the eccentric discs 9 is not limited to two. For example, one eccentric disk 9 may be provided on the input shaft 7.

DESCRIPTION OF SYMBOLS 1 Housing 3 Internal gear 4 Internal tooth 7 Input shaft 9 Eccentric disc 11 Shaft insertion hole 13 Bearing 14 Output shaft 16 Cage 19 Pocket 20 Roller 21 Spline 22 Ball groove 23 Rolling surface

Claims (6)

A fixed housing, an internal gear supported by the housing and provided with a plurality of internal teeth on the inner periphery, and a shaft end arranged coaxially with the internal gear and positioned inside the internal gear An input shaft provided with an eccentric disc at a portion thereof, a bearing supported on an outer diameter surface of the eccentric disc, and a shaft coaxially arranged with the input shaft, and rotatable at the end of the shaft within the internal gear An output shaft provided with a cage having a closed end, and a roller accommodated in a pocket formed in the cage and capable of rolling along the outer diameter surface of the bearing. In the speed reduction device that rotates the output shaft at a reduced speed relative to the rotation of the input shaft according to the number of teeth of the inner teeth per rotation,
The eccentric disc has a shaft insertion hole into which the input shaft is fitted at an eccentric position with respect to the center of the cylindrical outer diameter surface, and is separated from the input shaft. The eccentric disc is used as the input shaft. A speed reducer characterized by being fitted and locked.   The speed reducer according to claim 1, wherein the rotation stop is press-fitted.   The reduction gear according to claim 1, wherein the detent is a spline fitting or a serration fitting.   The reduction gear according to any one of claims 1 to 3, wherein the eccentric disk is formed by grinding an outer diameter surface of an eccentric disk shaped member formed by forging or pressing.   The speed reducer according to any one of claims 1 to 4, wherein a ball groove for guiding a ball of the bearing is formed on a cylindrical outer diameter surface of the eccentric disc.   The reduction gear according to any one of claims 1 to 4, wherein a rolling surface that guides the roller of the bearing is formed on a cylindrical outer diameter surface of the eccentric disc.

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