JP6277002B2 - Gears and inscribed planetary gears - Google Patents

Description

  The present invention relates to a gear and an inscribed planetary gear device, and more particularly to an improved gear for backlash and an inscribed planetary gear device using the gear.

  As an improved gear for backlash, an elastic portion is provided between a gear body portion formed of a hub portion or the like and a ring-shaped peripheral portion having a series of tooth portions, and the elastic portion is subjected to elastic deformation in the toothing direction. Or a structure having a structure in which the tooth portion is engaged and pressed against the tooth portion of the mating partner (for example, Patent Documents 1, 2, and 3; this is referred to as Conventional Example 1), and each tooth portion is divided in the tooth thickness direction. And an elastic part, and has a structure in which the tooth part is engaged and pressed against the tooth part of the other party under the elastic deformation of the elastic part in the tooth thickness direction (for example, Patent Document 4). Is known).

JP-A-8-177987 Japanese Patent No. 4585154 JP 2003-74646 A JP 2013-250272 A

  As for the meshing of the gear, even if there is only one meshing tooth portion that substantially transmits torque, the delaying tooth portion adjacent to the meshing gear advances, and the leading tooth portion tends to be disengaged from the meshing. Therefore, when the series of tooth portions are collectively displaced by the elastic deformation of the elastic portion, there is a possibility that interference occurs in the meshing of the delay side and the advance side tooth portions. For this reason, in the prior art example 1, since the elastic portion collectively supports the series of tooth portions, there is a possibility that interference occurs in the meshing even if the backlash is eliminated.

  Since the gear of Conventional Example 2 is composed of a combination of a highly rigid portion and an elastic portion whose tooth portions are divided in the tooth thickness direction, the tooth shape changes due to elastic deformation of the elastic portion, and the tooth shape is not fixed. Therefore, even if the backlash is eliminated, torque transmission is not stable.

  Further, in the internal planetary gear device used as a hypocycloid type reduction gear, the difference in the number of teeth of the external gear and the number of teeth of the internal gear is small, the larger the number of teeth of the external gear, A large reduction ratio can be obtained, but the smaller the difference in the number of teeth and the greater the number of teeth of the external gear, the more the external teeth add to the internal teeth when the external teeth of the external gear are extracted from the tooth spaces of the internal gear. It is easy to cause trochoid interference that interferes with the tooth tip of the tooth. Trochoid interference not only hinders smooth torque transmission, but also damages the external gear and the internal gear and shortens the mechanical life of the gear.

  In order to avoid trochoidal interference, it is necessary to limit the number of meshing teeth or lower the tooth depth, leading to a decrease in transmission torque due to a reduction in the number of meshing teeth and a decrease in transmission torque due to a reduction in meshing area. Become.

  The problem to be solved by the present invention is to eliminate backlash without causing interference in the meshing of the gear, and to avoid and mitigate trochoidal interference without causing other adverse effects.

  The gear according to the present invention is a gear (28) having a plurality of teeth (30) in a gear body (32), and forms a tooth profile (30A) to which the teeth (30) are fixed. The tooth part (30) is connected to the gear body part (32) by an elastic part (34, 40, 46, 48) that is elastically deformable in at least the tooth direction provided for each tooth part (30). Has been. The elastic portion (34, 40, 46, 48) is a zigzag shape or meander shape that is folded back multiple times in the tooth thickness direction of the tooth portion (30), or a rollover V shape that is folded back in the tooth thickness direction of the tooth portion (30). It can be constituted by a shape or a piece of the tooth portion (30) inclined in the tooth thickness direction.

  According to this structure, the tooth part (30) in the meshing part corresponds to each tooth part (30) corresponding to each tooth part (30) due to elastic deformation in the direction of toothing of the elastic part (34, 40, 46, 48). Since each of the tooth portions (30) in the meshing portion does not affect or give to the meshing of the other adjacent tooth portions (30), the tooth of the corresponding meshing partner is pressed. Backlash is eliminated while maintaining proper meshing for each part (22). Further, trochoidal interference is avoided and alleviated by the displacement of the tooth portion (30) in the toothpaste direction due to elastic deformation of the elastic portions (34, 40, 46, 48).

  In the gear according to the present invention, preferably, a displacement restricting portion (36, 42) for individually restricting the displacement in the tooth thickness direction of each tooth portion (30) is provided in the gear main body portion (32).

  According to this configuration, the displacement of the tooth portion (30) in the tooth thickness direction is limited, and the relative rotational phase of the meshing gear is not greatly increased.

  In the gear according to the present invention, preferably, a displacement restricting portion (36) for restricting the displacement in the tooth thickness direction of each tooth portion (30) to zero is provided in the gear main body portion (32).

  According to this configuration, since the tooth portion (30) is not displaced in the tooth thickness direction due to the presence of the displacement restricting portion 36, the relative rotational phase of the meshing gear does not shift.

  In the gear according to the present invention, preferably, the gear main body portion (32), the elastic portion (34, 40, 46, 48) and the tooth portion (30) are integrally formed from one material.

  According to this configuration, the number of parts of the gear does not increase and high mechanical strength can be obtained.

  An inscribed planetary gear device according to the present invention includes an input shaft (10), an external gear (20) eccentrically attached to the input shaft (10) and rotatably attached to the outer peripheral portion (22). An internal gear (28) which is arranged concentrically with the input shaft (10) and has internal teeth (30) which mesh with the external teeth (22) only on the eccentric side of the external gear (20) on the inner periphery. The internal gear (20) or the external gear (28) is constituted by the gear according to the invention described above.

  According to this configuration, trochoidal interference is avoided and alleviated by displacement in the tooth direction of the tooth portion (30) due to elastic deformation of the elastic portions (34, 40, 46, 48), so a measure for avoiding trochoidal interference Without reducing the number of teeth between the number of teeth (Za) of the external gear (20) and the number of teeth (Zb) of the internal gear (28), and the number of teeth (Za) of the external gear (20). ) Can be increased, and an inscribed planetary gear device having a large reduction ratio can be obtained.

  According to the gear according to the present invention, the tooth portion in the meshing portion is individually pressed against the tooth portion of the meshing counterpart corresponding to each tooth portion due to elastic deformation in the direction of toothing of the elastic portion. Backlash is eliminated by maintaining proper meshing for each of the teeth of the corresponding mating counterpart without affecting or being given to the meshing of other adjacent teeth. Further, the trochoidal interference is avoided and alleviated by the displacement of the tooth portion in the direction of the toothpaste due to the elastic deformation of the elastic portion.

BRIEF DESCRIPTION OF THE DRAWINGS The front view of the principal part which shows Embodiment 1 of the gearwheel by this invention, and an internal planetary gear apparatus. 1 is a longitudinal sectional view of a gear and an inscribed planetary gear device according to Embodiment 1. FIG. FIG. 3 is an enlarged cross-sectional view of a main part of the gear according to the first embodiment. The expanded sectional view of the principal part of Embodiment 2 by the gearwheel by this invention. The expanded sectional view of the principal part of Embodiment 3 by the gearwheel by this invention. The expanded sectional view of the principal part of the modification of the gearwheel by Embodiment 3. FIG. The expanded sectional view of the principal part of Embodiment 4 by the gearwheel by this invention. The expanded sectional view of the principal part of Embodiment 5 by the gearwheel by this invention.

  Embodiment 1 of a gear and an inscribed planetary gear device (hypocycloid speed reducer) according to the present invention will be described below with reference to FIGS.

  The cycloid speed reducer has an input shaft (input member) 10 that is rotatably provided around its own central axis by two ball bearings 12 that are separated in the axial direction. A recess 10 </ b> A is formed at one place in the circumferential direction of the input shaft 10. An eccentric block 14 and a wedge member 16 are provided in the recess 10A.

  A ball bearing 18 is eccentrically arranged on one side in the radial direction with respect to the input shaft 10 by an eccentric block 14 and a wedge member 16 on the outer peripheral portion of the input shaft 10. The eccentric block 14 is pressed against the inner peripheral portion of the inner race 18 </ b> A by a wedge member 16 driven between the eccentric block 14 and the outer peripheral portion of the input shaft 10, and thereby the inner race of the ball bearing 18. 18A is fixed to the outer periphery of the input shaft 10 in an eccentric state.

  An external gear (planetary gear) 20 is fixed to the outer peripheral portion of the outer race 18 </ b> B of the ball bearing 18. As a result, the external gear 20 is arranged eccentrically with respect to the input shaft 10 and is rotatable around its own central axis at a position eccentric with respect to the input shaft 10. A series of external teeth (tooth portions) 22 are formed on the outer peripheral portion of the external gear 20. An output member 26 is connected to the external gear 20 by an Oldham coupling 24. The output member 26 is arranged concentrically with the input shaft 10 and is rotatably supported by one of the two ball bearings 12.

  An annular internal gear (sun gear) 28 having a series of internal teeth (tooth portions) 30 on the inner peripheral portion is disposed on the outer peripheral side of the external gear 20. The internal gear 28 is disposed concentrically with the input shaft 10. As a result, the internal gear 28 is arranged eccentrically with respect to the external gear 20. Since the amount of eccentricity between the internal gear 28 and the external gear 20 is larger than the meshing teeth of the external teeth 22 and the internal teeth 30, the external teeth 22 and the internal teeth 30 mesh only on the eccentric side.

  In this internal planetary gear device, when the input shaft 10 rotates while the internal gear 28 is fixed to a fixing member (not shown), the external gear is engaged with the external teeth 22 and the internal teeth 30. 20 is revolved around the central axis of the input shaft 10 while rotating around its own central axis, and the output member 26 is decelerated with respect to the rotational speed of the input shaft 10 to obtain a decelerating action. The reduction ratio R of the internal planetary gear device is expressed by the following equation, where Za is the number of teeth of the external gear 20 and Zb is the number of teeth of the internal gear 28.

  R = Za / (Za-Zb)

  Accordingly, the smaller the tooth number difference between the number of teeth Za of the external gear 20 and the number of teeth Zb of the internal gear 28 (minimum = 1) and the larger the number of teeth Za of the external gear 20, the greater the reduction ratio R is obtained. .

  Next, details of the internal gear 28 will be described. The internal gear 28 has a gear main body 32 made of an annular rigid body. The internal tooth 30 has a fixed tooth shape portion 30A that does not change its shape and a rectangular portion 30B that is integrally formed on the tooth base side of the tooth shape portion 30A as a rigid structure. Here, the rigid body and the rigid structure refer to a rigid body that does not substantially undergo elastic deformation under normal use.

  The internal teeth 30 are connected to the gear main body 32 by the elastic portions 34 provided for the rectangular portions 30 </ b> B for each of the internal teeth 30. The elastic portion 34 is a cantilever beam extending radially inward of the internal gear 28 from the gear body portion 32, and is configured in a zigzag shape that is folded back multiple times in the tooth thickness direction of the internal teeth 30, so It is elastically deformable in the tooth thickness direction, and has an internal tooth 30 integrally at the tip.

  On both sides of the internal teeth 30 adjacent to each other in the tooth thickness direction, linear displacement regulating portions 36 extending from the gear main body portion 32 inward in the radial direction of the internal gear 28 are formed. That is, the internal teeth 30 and the elastic portions 34 and the displacement restricting portions 36 are alternately formed with a gap 38 in the circumferential direction of the gear main body portion 32.

  The displacement restricting portion 36 is a rigid body that is less likely to be elastically deformed than the elastic portion 34, preferably a rigid body that does not substantially undergo elastic deformation under normal use, and the displacement of the internal teeth 30 in the tooth thickness direction is reduced in the gap 38. Each internal tooth 30 is individually regulated within the range. This restriction is performed by the side surface of the rectangular portion 30 </ b> B in the tooth thickness direction coming into contact with the opposite side surface of the displacement restricting portion 36 and restricts the elastic deformation of the elastic portion 34 in the tooth thickness direction.

  The internal gear 28 is formed by integrally forming the gear main body 32, the elastic portion 34, the internal teeth 30 and the displacement restricting portion 36 from one material by press molding, laser processing or the like. Thereby, the number of parts of the internal gear 28 does not increase, and high mechanical strength can be obtained.

  According to the internal gear 28, the internal teeth 30 in the meshing portion with the external gear 20 are individually pressed against the external teeth 22 corresponding to the internal teeth 30 by the elastic deformation of the elastic portion 34 in the tooth-pitch direction. Therefore, the internal teeth 30 in the meshing portion do not affect or give to the meshing of the other adjacent internal teeth 30, and the proper meshing of the corresponding external teeth 22 is maintained, so that the backlash is eliminated. The

  Further, the trochoidal interference is avoided and alleviated by the displacement of the inner teeth 30 due to the elastic deformation of the elastic portion 34 and the displacement in the tooth thickness direction limited by the displacement restricting portion 36. Accordingly, in order to avoid trochoidal interference, the difference in the number of teeth between the number of teeth Za of the external gear 20 and the number of teeth Zb of the internal gear 28 is reduced, or the number of teeth Za of the external gear 20 is increased. Therefore, an inscribed planetary gear unit having a large reduction ratio can be obtained.

  In addition, to avoid trochoidal interference, it is not necessary to limit the number of meshing teeth or lower the toothing, avoiding a decrease in transmission torque due to a reduction in the number of meshing teeth or a decrease in transmission torque due to a reduction in meshing area. can do.

  Further, since the elastic deformation 34 is restricted in the tooth thickness direction by contacting the side surface of the displacement restricting portion 36 where the side surface of the rectangular portion 30B in the tooth thickness direction opposes, The displacement is limited, and the relative rotational phase between the external gear 20 and the internal gear 28 is not greatly increased.

  Next, Embodiment 2 of the gear according to the present invention will be described with reference to FIG. 4, parts corresponding to those in FIG. 3 are denoted by the same reference numerals as those in FIG. 3, and description thereof is omitted.

  In the present embodiment, the internal teeth 30 and the gap 38 between the elastic portion 34 and the displacement restricting portion 36 of the first embodiment are set to zero, and the internal teeth 30 are only in the toothpaste direction due to the elastic deformation of the elastic portion 34. The structure is displaceable and cannot be displaced in the tooth thickness direction.

  In the present embodiment, the effect of eliminating backlash and avoiding or mitigating trochoidal interference is obtained by displacement in the direction of the teeth of the internal teeth 30. In addition, since the internal teeth 30 are not displaced in the tooth thickness direction due to the presence of the displacement restricting portion 36, there is no deviation in the relative rotational phase between the external gear 20 and the internal gear 28. Further, the displacement restricting portion 36 plays a role of torque transmission, so that large torque transmission can be performed.

  Next, a third embodiment of the gear according to the present invention will be described with reference to FIG.

  In the present embodiment, the elastic portion 40 that connects the rectangular portion 30B of the internal tooth 30 to the gear main body portion 32 is constituted by a spring piece that is inclined in the tooth thickness direction of the tooth portion. Displacement restricting portions 42 extending from the gear main body portion 32 inward in the radial direction of the internal gear 28 are provided on both sides adjacent to the tooth thickness direction of the internal teeth 30. The displacement restricting portion 42 has a bent shape with a gap 44 on the side surface in the tooth thickness direction of the rectangular portion 30B, and has a side surface facing in the tooth thickness direction. Limit to 44.

  In the present embodiment, the elastic portion 40 is elastically deformed like a leaf spring with the connection base portion with the gear main body portion 32 as a fulcrum, and therefore, the internal teeth 30 of the elastic portion 40 asymmetric with respect to the rotational direction of the external gear 20. Elastically deforms in the toothpick direction and tooth thickness direction.

  Also in this embodiment, the effect of eliminating backlash and avoiding or mitigating trochoidal interference can be obtained by the displacement of the inner teeth 30 in the tooth direction and the displacement in the tooth thickness direction due to the elastic deformation of the elastic portion 40.

  The displacement restricting portion 42 also acts as a second elastic portion that is less likely to be elastically deformed than the elastic portion 40. By the displacement, the backlash can be eliminated and the trochoid interference can be avoided and mitigated more effectively.

  As a modification of the third embodiment, the displacement restricting portion 42 may be omitted as shown in FIG.

  Next, Embodiment 4 of the gear according to the present invention will be described with reference to FIG.

  In the present embodiment, the elastic portion 46 that connects the rectangular portion 30 </ b> B of the inner tooth 30 to the gear main body portion 32 is configured by a spring piece in a rollover V shape that is folded back in the thickness direction of the inner tooth 30.

  Also in the present embodiment, as in the first embodiment, the elastic portion 46 is elastically deformed by the displacement of the inner teeth 30 in the tooth direction and the displacement in the tooth thickness direction. By the displacement in the toothpaste direction and the displacement in the tooth thickness direction, effects of eliminating backlash and avoiding or mitigating trochoid interference can be obtained.

  Next, a fifth embodiment of the gear according to the present invention will be described with reference to FIG.

  In the present embodiment, the elastic portion 48 that connects the rectangular portion 30 </ b> B of the inner tooth 30 to the gear main body portion 32 is configured in a rollover U shape that is repeatedly folded back in the thickness direction of the inner tooth 30, that is, a meander shape.

  Also in the present embodiment, as in the first embodiment, the elastic portion 48 is elastically deformed by displacement in the toothpick direction and displacement in the tooth thickness direction of the internal teeth 30, and the teeth of the internal teeth 30 due to elastic deformation of the elastic portions 46. By the displacement in the bamboo direction and the displacement in the tooth thickness direction, effects of eliminating backlash and avoiding or mitigating trochoidal interference can be obtained.

  Although the present invention has been described above with reference to preferred embodiments thereof, the present invention is not limited to such embodiments and can be deviated from the spirit of the present invention, as will be readily understood by those skilled in the art. It is possible to change appropriately within the range not to be.

  The internal gear 28 according to the third and fourth embodiments shown in FIGS. 5 to 7 is directed according to the forward / reverse direction of torque, that is, the forward / reverse rotation direction of the external gear 20, depending on the shape of the elastic portions 40 and 46. However, it is possible to eliminate the directionality by forming the internal gear 28 by a laminated body of steel plates and then laminating the steel plates by inverting the front and back of each steel plate or every plurality of steel plates. Further, the connection between the external gear 20 and the output member 26 is not limited to the Oldham coupling, and can be performed by a deflectable coupling or the like that can be eccentric.

  The gear according to the present invention is not limited to the internal gear of the inscribed planetary gear device, but can be applied to the external gear in the same manner, and can also be applied to the spur gear, the bevel gear, the rack, and the like.

  In addition, all the components shown in the above embodiment are not necessarily essential, and can be appropriately selected without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Input shaft 14 Eccentric block 16 Wedge member 18 Ball bearing 20 External gear 22 External tooth 24 Oldham coupling 26 Output member 28 Internal gear 30 Internal tooth 30A Tooth profile part 30B Rectangular part 32 Gear body part 34 Elastic part 36 Displacement regulation part 38 Gap 40 Elastic part 42 Displacement restricting part 44 Gap 46 Elastic part 48 Elastic part

Claims (7)

A gear having a plurality of teeth on the gear body,
The tooth part forms a fixed tooth profile,
The tooth portion is connected to the gear main body portion by an elastic portion that is elastically deformable in at least the tooth direction provided for each tooth portion ;
Furthermore, the gear main-body part is provided with the displacement control part which controls the displacement of the tooth thickness direction of each said tooth part separately . A gear having a plurality of teeth on the gear body,
The tooth part forms a fixed tooth profile,
The tooth portion is connected to the gear main body portion by an elastic portion that is elastically deformable in at least the tooth direction provided for each tooth portion ;
Further, the gear main body portion is provided with a displacement restricting portion for restricting a displacement in the tooth thickness direction of each tooth portion to zero . The gear according to claim 1 or 2 , wherein the elastic portion is formed in a zigzag shape or a meander shape that is bent back and forth several times in the tooth thickness direction of the tooth portion. The gear according to claim 1 or 2 , wherein the elastic part is configured in a rollover V shape that is folded back in a tooth thickness direction of the tooth part. The gear according to claim 1 or 2 , wherein the elastic part is constituted by a piece part inclined in the tooth thickness direction of the tooth part. The gear according to any one of claims 1 to 5, wherein the gear body portion, the elastic portion, and the tooth portion are integrally formed from a single material. An input shaft;
An external gear attached to the input shaft so as to be eccentric and rotatable, and having external teeth on the outer peripheral portion;
An internal planetary gear device having an internal gear arranged concentrically with the input shaft and having an internal gear having an internal gear meshing with the external gear only on the eccentric side of the external gear on the inner peripheral portion,
The internal planetary gear device, wherein the internal gear or the external gear is constituted by the gear according to any one of claims 1 to 6 .

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