JP2011052765A - Reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure tooth face accuracy of an internal gear, and to suppress manufacturing costs of the internal gear. <P>SOLUTION: An input shaft 12 and an output shaft 13 rotatably supported on a housing 11, and the internal gear 14 fixed to the housing 11 are coaxially arranged, and a roller 21 is held so as to roll by a retainer 22 between the internal gear 14 and an eccentric shaft 18 provided on the input shaft 12. The internal gear 14 is formed by overlapping a plurality of pieces of plate internal gears 30 in a state of matching circumferential positions of its teeth 32, and it is loosely fit in the housing 11. An engaging means for stopping the rotation of each plate internal gear 30 with respect to the housing 11 is formed of an engagement groove 15a in an axial direction provided in the housing 11, and a protrusion 31 provided on the outer periphery of the plate internal gear 30 fitting in the engagement groove 15a. The internal gear 14 is fixed with respect to the housing 11 by the engaging means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a speed reducer that decelerates rotation of an input shaft and transmits it to an output shaft.

  Generally, a reduction device is known as a device that decelerates the rotation of an input shaft that receives a driving force from a driving source such as a DC motor, transmits the rotation to an output shaft, and drives a counterpart machine connected to the output shaft.

  As such a reduction gear, for example, an input shaft 42 and an output shaft 43 rotatably supported by a cylindrical housing 41 as shown in FIG. 8 and an internal gear 44 fixed in the housing 41 are coaxial. A plurality of rollers 46 are interposed between the eccentric shaft 45 having a circular cross section provided on the input shaft 42 and the internal gear 44, and pockets for holding the rollers 46 are arranged at equal pitches in the circumferential direction. There is one in which an annular retainer portion 47 provided is provided on the output shaft 43 (see Patent Document 1).

JP 62-93565 A

  As shown in FIG. 9, the cage portion 47 is thinned out at a part of the dividing point that is one more than the number of teeth of the internal gear 44 when the dividing portion 47 is divided at an equal pitch in the circumferential direction. It has a structure having a pocket 48 for holding the roller 46 at a position.

  When the input shaft 42 is rotated once in one direction, the roller 46 is pressed against the teeth of the internal gear 44 by the outer peripheral portion of the input shaft 42, and one tooth (one person in the same direction as the input shaft 42 with respect to the teeth of the internal gear 44). Tooth) and revolve around the axis of the input shaft 42 in the same direction. Due to the revolution of the roller 46, the rotation of the reduction ratio corresponding to the number of teeth of the internal gear 44 is transmitted to the output shaft 43 through the cage portion 47.

  In the reduction gear device described in Patent Document 1, the internal gear 44 is formed in a cylindrical shape having a width in the axial direction because it is necessary to interpose a roller 46 between the internal gear 44 and the eccentric shaft portion 45, as shown in FIG. It is fixed to the housing 41 by press fitting. The press-fitted and fixed internal gear 44 is prevented from rotating with respect to the housing 41, and the roller 46 is pressed against the teeth of the internal gear 44 along with the rotation of the input shaft 42 to prevent it from rotating together with the roller 46. It was.

  However, the internal gear 44 is compressed by receiving a radially inward load from the inner surface of the housing 41 due to the press-fitting to the housing 41, the tooth surface accuracy is lowered, and the roller 46 is not smoothly revolved. There was a problem that transmission of smooth rotation to the output shaft was hindered.

  Further, as described above, since the internal gear 44 is formed in a cylindrical shape having a width in the axial direction, it is necessary to form teeth on the inner peripheral portion by broaching or the like after forming a cylindrical outer portion. There was a production cost.

  Accordingly, an object of the present invention is to secure the tooth surface accuracy of the internal gear and to suppress the manufacturing cost of the internal gear.

  In order to solve the above-mentioned problems, the present invention has an input shaft and an output shaft that are rotatably supported by a housing, and an internal gear that is fixed in the housing coaxially arranged, and the input shaft has a circular cross section. An annular cage in which a plurality of rollers are interposed between the internal gear and the eccentric shaft portion provided therein, and pockets for holding the rollers are provided at equal pitches in the circumferential direction. A portion is provided on the output shaft, and the annular cage portion has all the positions of the dividing points when the number of dividing points is different by one from the number of teeth of the internal gear when divided in the circumferential direction at an equal pitch. Or having a pocket for holding the roller in a part of the thinned-out position, and the shape corresponding to one pitch of the teeth revolves along the outer peripheral portion of the eccentric shaft portion when the input shaft rotates. Among the curves parallel to the locus drawn by the center of the roller, In the reduction gear that matches the curve on the outer diameter side of the roller and transmits the revolution of the roller to the output shaft through the retainer portion, the internal gear includes a plurality of plate-like internal gears. The teeth are overlapped with each other in the circumferential position, and are fitted into the housing so as to form a clearance fit. The plate-like internal gears are prevented from rotating with respect to the housing. A configuration is employed in which an engaging means is provided and the internal gear is fixed in the housing by the engaging means.

  In this configuration, the internal gear is formed by overlapping a plurality of plate-like internal gears in a state where the circumferential positions of the teeth are matched, and is fitted into the housing so as to be a clearance fit. For this reason, each plate-like internal gear that forms the internal gear fitted in the housing is not subjected to a radially inward load from the inner surface of the housing, unlike the internal gear of the conventional reduction gear. Therefore, the reduction of the tooth surface accuracy of each plate-like internal gear is prevented, and the internal gear formed of a plurality of plate-like internal gears can ensure the tooth surface accuracy.

  Further, as the plate-like internal gear forming the internal gear, it is possible to form teeth together with the formation of the outer portion of the plate-like internal gear by processing the plate material, and it is possible to reduce the manufacturing cost.

  Further, the internal gear formed from the plate-like internal gear is fitted to the housing so as to be a clearance fit by the engaging means for preventing the rotation of each plate-like internal gear with respect to the housing. Is also locked and secured within the housing.

  A structure in which the engaging means is formed by an axial groove provided in the housing and a protrusion provided on an outer peripheral portion of the plate-like internal gear fitted in the groove, or a shaft provided in the housing It can be set as the structure formed by the protrusion of a direction and the recessed part provided in the outer peripheral part of the said plate-shaped internal gear with which the protrusion protrudes.

  If the engaging means having such a configuration is applied, the projection of the plate-like internal gear is engaged with the groove of the housing or the recess of the plate-like internal gear is engaged with the protrusion of the housing. As a result, the assemblability of the reduction gear can be improved.

  The engaging means includes a hole provided in the plate-like internal gear, a screw hole provided in the housing, and a screw member that penetrates the hole of the plate-like internal gear and is coupled to the screw hole of the housing. If formed by this, a plurality of plate-like internal gears can be firmly fixed in the housing by the screw member.

  When the configuration of the engaging means using the screw member is adopted, a plurality of holes in the plate-like internal gear are provided at intervals in the circumferential direction, and screw holes in the housing are arranged in the circumferential direction of the holes in the plate-like internal gear. When a plurality of configurations corresponding to the positions are employed, the internal gear formed from each plate-like internal gear can be firmly fixed to the housing over the entire circumference in the circumferential direction.

  In the above configuration, when the plate-like internal gear is formed by press working, teeth are formed together with the outer portion of the plate-like internal gear by press working, and broaching or the like required when manufacturing the teeth of the conventional internal gear is performed. It becomes unnecessary and the manufacturing process can be simplified, the productivity can be increased and the manufacturing cost 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 the thinning interval is made uniform in the circumferential direction, so that the rotation balance of the output shaft is kept good, and the pocket The number of processing and the number of rollers can be reduced.

  If the outer peripheral portion of the eccentric shaft portion is formed by the outer peripheral portion of a rolling bearing fitted to the outer periphery of the eccentric shaft portion, slip between the roller and the outer diameter surface of the eccentric shaft portion can be suppressed.

  Moreover, in order to improve the strength and wear resistance of the teeth of the plate-like internal gear, induction hardening can be performed on the tooth surfaces of the plate-like internal gear. Furthermore, in order to improve the mechanical strength of the plate-like internal gear, the plate-like internal gear may be carburized.

In the speed reducer according to the present invention, each plate-like internal gear has a tooth surface because no load is applied radially inward from the inner surface of the housing to each plate-like internal gear that forms the internal gear fitted in the housing. The reduction in accuracy is prevented, and the internal gear formed by a plurality of plate-like internal gears can ensure the tooth surface accuracy.
In addition, since the internal gear is formed by superimposing a plurality of plate-like internal gears, it is possible to form teeth along with the formation of the outer shape portion of the plate-like internal gear by processing the plate material, thereby reducing the production cost. It becomes possible.

Sectional drawing which shows Example 1 of the reduction gear device which concerns on this invention Sectional view along the II-II line of FIG. (A) The perspective view which shows the internal gear of Example 1, (b) The perspective view which shows the plate-shaped internal gear which forms the internal gear same as the above. The perspective view which shows the principal part same as the above Sectional drawing which shows Example 2 of the speed reducer based on this invention Sectional drawing along the VI-VI line of FIG. (A) Perspective view showing the internal gear of Example 2, (b) Perspective view showing the plate-like internal gear forming the internal gear of the above. Sectional view showing a conventional speed reducer Sectional drawing along the IX-IX line of FIG. A perspective view showing an internal gear of a conventional reduction gear

  1 to 4 show a first embodiment of a reduction gear according to the present invention.

  As shown in FIG. 1, in the speed reducer in this embodiment, an input shaft 12 and an output shaft 13 that are rotatably supported by a cylindrical housing 11 and an internal gear 14 fixed in the housing 11 are coaxial. Are arranged in a shape.

  The housing 11 is formed by fitting cylindrical bodies divided in the axial direction by known means (not shown). The input shaft 12 is rotatably supported at one end and the output shaft 13 is rotatably supported at the other end. Has been. An engagement groove 15a (see FIG. 2) is provided on the inner surface of the housing 11 on the input shaft 12 side.

  The input shaft 12 is rotatably supported by bearings 16 and 17 at one end portion of the housing 11 and the large-diameter portion 13b of the output shaft 13. Between the bearings 16 and 17 of the input shaft 12, a pair of circular eccentric shaft portions 18 and 18 are integrally provided at two locations in the axial direction. The eccentric shaft portion 18 is eccentric so that the shaft center sandwiches the shaft center of the input shaft 12, and a bearing 19 is press-fitted and fixed to the outer periphery thereof.

  As shown in FIG. 2, the internal gear 14 is fixed to the inner peripheral portion of the housing 11 and is arranged coaxially with the input shaft 12, and the inner peripheral portion of the internal gear 14 is a bearing 19 of a pair of eccentric shaft portions 18. It faces the outer peripheral part. As shown in FIG. 2, a plurality of teeth 32 (51 in the case of FIG. 2) are formed on the inner peripheral portion of the internal gear 14 at a constant pitch in the circumferential direction. A plurality of rollers 21 are interposed between the inner peripheral portion of the internal gear 14 and the bearing 19 of the eccentric shaft portion 18 so as to be in contact with them.

  As shown in FIG. 3A, the internal gear 14 is formed by overlapping a plurality of plate-like internal gears 30 with their circumferential positions of their teeth 32 matched. The plate-like internal gear 30 is made of a plate-shaped torus, and a plurality of teeth 32 are formed at an equal pitch on the inner peripheral portion, and radially outward projections 31 are formed on the outer peripheral portion (FIG. 3B). )reference). The protrusion 31 can be engaged with the engagement groove 15 a of the housing 11, and constitutes an engagement means with the engagement groove 15 a of the housing 11. The engaging means may be formed by engaging a radially inward recess formed in the plate-like internal gear 30 and an axial protrusion provided in the housing 11.

  The outer diameter of the plate-like internal gear 30 is slightly smaller than the inner diameter of the inner peripheral portion of the housing 11. Therefore, as shown in FIG. 3A, when the internal gear 14 is formed by overlapping a plurality of plate-like internal gears 30 in a state where the circumferential positions of the teeth 32 are matched, the internal gear 14 is The protrusions 31 of the respective plate-like internal gears 30 that are continuous in the axial direction are engaged with the engagement grooves 15 a of the housing 11, and can be fitted into the housing 11 so as to have a clearance fit. Due to the engagement between the projection 31 of the plate-like internal gear 30 and the engagement groove 15 a of the housing 11, the internal gear 14 is prevented from rotating with respect to the housing 11 and fixed in the housing 11.

  When the internal gear 14 is clearance-fitted in the housing 11, each plate-like internal gear 30 forming the internal gear 14 is not subjected to a radially inward load from the inner surface of the housing 11. For this reason, each of the plate-like internal gears 30 is prevented from lowering the tooth surface accuracy, and the internal gear 14 formed by the plurality of plate-like internal gears 30 can ensure the tooth surface accuracy.

  If the internal gears 14 are formed by overlapping the plate-like internal gears 30, the number of the plate-like internal gears 30 is appropriately selected according to the torque capacity of the reduction gear, and Since the width in the axial direction can be set, the versatility of the internal gear 14 is improved.

  The shape corresponding to one pitch of the teeth 32 of the plate-like internal gear 30 is a curve parallel to the locus drawn by the center of the roller 21 revolving along the outer periphery of the bearing 19 of the eccentric shaft portion 18 when the input shaft 12 rotates. Of these, it matches the curve outside the roller 21.

  The plate-like internal gear 30 can be formed by pressing a low carbon material such as a plate-like structural low carbon steel or low alloy steel. By forming by press working, the teeth 32 can be formed together with the outer shape portion of the plate-like internal gear 30, and broaching or the like required when manufacturing the teeth of the conventional internal gear becomes unnecessary. Therefore, the manufacturing process can be greatly simplified, the productivity can be increased, and the manufacturing cost can be reduced.

  In order to improve the mechanical strength of the plate-like internal gear 30, a carburizing process may be performed. Moreover, in order to improve the strength and wear resistance of the teeth of the plate-like internal gear 30, induction hardening can be performed on the surfaces of the teeth 32 of the plate-like internal gear 30. Here, the carburizing treatment is a method in which carbon is infiltrated / diffused from the surface of the low carbon material and then quenched. Induction hardening is a hardening method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current is flowing and generating electromagnetic Joule heat. .

  The output shaft 13 has a small-diameter portion 13a located on the other end side of the housing 11 and a large-diameter portion 13b located closer to the input shaft 12 than the small-diameter portion 13a. The bearing 11 is rotatably supported by bearings 24 at two axial positions on the other end of the housing 11.

  The large-diameter portion 13b of the output shaft 13 has a cylindrical shape, and has a tapered portion whose outer diameter gradually increases from the other end portion to the one end portion at the outer peripheral portion, and is input by a bearing 17 fitted to the inner peripheral portion. The other end of the shaft 12 is rotatably supported. An annular retainer portion 22 is coaxially and integrally formed at one end portion of the large diameter portion 13b of the output shaft 13. The cage portion 22 is located between the internal gear 14 and the bearings 19 of both eccentric shaft portions 18.

  The cage portion 22 has pockets 23 formed at equal pitches in the circumferential direction, and a plurality of rollers 21 interposed between the internal gear 14 and the bearing 19 of the eccentric shaft portion 18 are accommodated in the pocket 23 so as to be able to roll. The The pockets 23 are formed in two rows in the axial direction with a half-pitch deviation from the pitch (see FIG. 4).

  The pockets 23 are provided in one number different from the number of teeth 32 of the internal gear 14 (plate-shaped internal gear 30). For example, the pockets 23 are equally divided in the circumferential direction by one more than the number of teeth 32 of the internal gear 14. In this case, positions are thinned out every third division point (13 places in the case of FIG. 2), that is, the thinning intervals are provided so as to be equal in the circumferential direction. Thereby, the rotation balance of the output shaft 13 can be kept favorable, and the number of processing of the pocket 23 and the number of incorporation of the rollers 21 can be reduced.

  Here, “the pockets 23 are provided in different numbers with respect to the teeth 32 of the internal gear 14” means not only the case where the pockets 23 are provided at all positions with respect to the dividing point, but also a part thereof. This also includes the case where it is provided at a thinned position. Moreover, you may provide the pocket 23 in the number one less than the number of the teeth 32 of the internal gear 14 (plate-shaped internal gear 30).

  The operation of the speed reducer having the above configuration will be described.

  As indicated by an arrow in FIG. 2, the input shaft 12 rotates clockwise, and the minimum portion A of the annular space between the outer peripheral surface of the outer ring of the bearing 19 of the eccentric shaft portion 18 and the internal gear 14 having the teeth 32 is the timepiece. Assuming that the rotation angle is 0 ° and the maximum portion B is 180 °, the minimum portion A and the maximum portion B move clockwise as the input shaft 12 rotates, and the right half of the annular space is narrow. The left half of the annular space tends to become wider. For this reason, the roller 21 existing in the right half of the annular space moves in the outer diameter direction down the teeth 32 of the internal gear 14, and the roller 21 existing in the left half of the annular space moves in the inner diameter direction above the teeth 32. As indicated by the arrows, the cage portion 22 of the output shaft 13 that holds the roller 21 rotates in the same clockwise direction as the input shaft 12.

  In the first embodiment, since the number N of the dividing points of the cage portion 22 is one more than the number of teeth 32, each rotation of the input shaft 12 makes each roller 21 clockwise by one pitch of the teeth 32. Revolution, the reduction ratio of the input shaft 12 and the output shaft 13 becomes equal to the number N of division points. When the number N of division points is one less than the number of teeth 32, each roller 21 revolves counterclockwise, and the output shaft 13 rotates in the direction opposite to the input shaft 12.

  A second embodiment of the reduction gear according to the present invention is shown in FIGS.

  The speed reduction device according to the second embodiment is different from the first embodiment in the engagement means for preventing the rotation of each plate-like internal gear 30 that forms the internal gear 14 with respect to the housing 11. Other configurations are the same as those of the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof is omitted.

  Specifically, in the second embodiment, as an engaging means, a through hole 33 provided in a plate-like internal gear 30 forming the internal gear 14 and an end surface near the outer peripheral portion of the housing 11 in the axial direction. The screw holes 15b and 15c are provided, and screw members 34 that pass through the through holes 33 of the plate-like internal gear 30 and are coupled to the screw holes 15b and 15c of the housing 11 (see FIG. 5).

  As shown in FIG. 7B, a plurality of through holes 33 (six in the case of FIG. 6) are provided in the circumferential direction so as to match the position of each through hole 33. Further, screw holes 15b and 15c are provided in the housing 11 in six axial directions. The number of the through holes 33 of the plate-like internal gear 30 is not particularly limited, but may be provided at one place, two places,... As long as the effect of the engagement means is exhibited. By providing at six places, the internal gear 14 can be firmly fixed to the housing 11 over the entire circumference in the circumferential direction.

  As shown in FIG. 7A, the internal gear 14 is formed by overlapping the plate-like internal gear 30 in a state where the circumferential positions of the teeth 32 thereof are matched, as in the case of the first embodiment. It fits in the housing 11 so as to be a clearance fit. In this fitted state, the screw holes 15b and 15c of the housing 11 and the through-hole 33 of the plate-like internal gear 30 are matched to insert and tighten the screw member 34.

  By tightening the screw member 34, the internal gear 14 is prevented from rotating with respect to the housing 11, and is securely fixed to the housing 11, and the housing 11 that is broken in the axial direction is fixed.

DESCRIPTION OF SYMBOLS 11 Housing 12 Input shaft 13 Output shaft 13a Small diameter part 13b Large diameter part 14 Internal gear 15a Engagement groove 15b, 15c Screw hole 16, 17, 19, 24 Bearing 18 Eccentric shaft part 21 Roller 22 Cage part 23 Pocket 30 Plate shape Internal gear 31 Protrusion 32 Teeth 33 Through hole 34 Screw member 41 Housing 42 Input shaft 43 Output shaft 44 Internal gear 45 Eccentric shaft portion 46 Roller 47 Cage portion 48 Pocket

Claims (10)

  An input shaft (12) and an output shaft (13) rotatably supported by the housing (11) and an internal gear (14) fixed in the housing (11) are coaxially arranged, and the input shaft (12) is provided with an eccentric shaft portion (18) having a circular cross section, and a plurality of rollers (21) are interposed between the internal gear (14) and the eccentric shaft portion (18) provided therein, An annular cage portion (22) having pockets (23) for holding the rollers (21) provided at equal pitches in the circumferential direction is provided on the output shaft, and the annular cage portion (22) is arranged in the circumferential direction, etc. The number of dividing points when divided by pitch is different from the number of teeth (32) of the internal gear (14) by one, and the rollers (21) And the shape of one tooth of the teeth (32) when the input shaft (12) rotates, the eccentric shaft portion (18) A curve parallel to a trajectory drawn by the center of the roller (21) revolving along the outer periphery matches a curve on the outer diameter side of the roller (21), and the revolution of the roller (21) is controlled by the cage. In the speed reducer configured to transmit to the output shaft (13) via the portion (22), the internal gear (14) is configured to connect a plurality of plate-like internal gears (30) in the circumferential direction of the teeth (32). The plate-like internal gears (30) are formed so as to be overlapped with each other in a matched state, and are fitted into the housing (11) so as to form a clearance fit. A speed reducer characterized in that the internal gear (14) is fixed in the housing (11) by means of an engaging means for preventing rotation.   An axial groove (15a) provided in the housing (11) with the engaging means, and a protrusion (31) provided on the outer peripheral portion of the plate-like internal gear (30) fitted in the groove (15a) The speed reducer according to claim 1, wherein:   The engagement means is formed by an axial protrusion provided in the housing (11) and a recess provided in an outer peripheral portion of the plate-like internal gear to which the protrusion is fitted. Item 4. The reduction gear according to item 1.   A hole (33) provided in the plate-like internal gear (30) for the engaging means, screw holes (15b, 15c) provided in the housing (11), and a hole (15) in the plate-like internal gear (30) ( 33. The speed reducer according to claim 1, wherein the speed reducer is formed by a screw member (34) penetrating through 33) and coupled to the screw holes (15b, 15c) of the housing (11).   A plurality of holes (33) of the plate-like internal gear (30) are provided at intervals in the circumferential direction, and screw holes (15b, 15c) of the housing (11) are provided in the holes (30) of the plate-like internal gear (30). 33. The speed reducer according to claim 4, wherein a plurality of speed reducers are provided corresponding to the circumferential position of 33).   The speed reducer according to any one of claims 1 to 5, wherein the plate-like internal gear (30) is formed by press working.   The pocket (23) for holding the roller (21) of the retainer part (22) 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 the above.   The outer peripheral portion of the eccentric shaft portion (18) is formed by the outer peripheral portion of a rolling bearing (19) fitted to the outer periphery of the eccentric shaft portion (18). The speed reducer described in 1.   The reduction gear according to any one of claims 1 to 8, wherein the plate-like internal gear (30) is carburized.   The speed reducer according to any one of claims 1 to 9, wherein the surface of the teeth (32) of the plate-like internal gear (30) is induction-hardened.

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