JP2013087825A - Deflection engagement type gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize rollers for an excitation body bearing so as to prevent skew and reduce loss of transmission torque.SOLUTION: A deflection engagement type gear device 100 is equipped with: an excitation body 104; an external gear 120; excitation body bearing 110; an annulus gear 130A for deceleration; and an annulus gear 130B for output. While a gap Gp is provided whose size is increased as it extends toward the end part in the axial direction O of rollers 116A, 116B, between the rollers 116A, 116B prior to incorporation of an excitation body bearing 110 into the excitation body 104, and outer races 118A, 118B, whereas the size of the gap Gp is made to be equal to or greater than the amount of deformation of the outer races 118A, 118B under the state of the excitation body bearing 110 being incorporated in the excitation body 104.

Description

  The present invention relates to a flexure meshing gear device.

  A flexure meshing gear device disclosed in Patent Document 1 includes a vibrating body, and a cylindrical external gear having flexibility that is arranged on the outer periphery of the vibrating body and is bent and deformed by rotation of the vibrating body. And a vibration body bearing having a roller rotatably supporting the external gear between the vibration body and the external gear, and an outer ring provided outside the roller, and the external gear And an internal gear having rigidity for internal meshing.

JP 2009-299765 A

  In the flexibly meshing gear device described in Patent Document 1, as described above, rollers are used for the vibration generator bearings. For this reason, compared with the case where a ball bearing is used, a vibration body bearing can be made long-life. However, the roller of this vibration body bearing may revolve outside the vibration body on a non-circular raceway, and is likely to cause skew, resulting in a loss of transmission torque.

  Accordingly, the present invention has been made to solve the above-described problems, and a flexure meshing gear device that prevents skew while using a roller for a vibration generator bearing and that can reduce loss of transmission torque. The issue is to provide.

  The present invention includes a vibrator, a cylindrical external gear that is arranged on an outer periphery of the vibrator and has a flexibility that is bent and deformed by rotation of the vibrator, the vibrator and the outer A vibration body bearing having a roller rotatably supporting the external gear between the toothed gear and an outer ring provided on the outer side of the roller; and a rigid inner for meshing the external gear. In a flexure meshing gear device including a toothed gear, between the roller and the outer ring before the vibration generator bearing is incorporated in the vibration generator, toward the axial end of the roller An increasing gap is provided, and the size of the gap is equal to or greater than the amount of deformation of the outer ring in a state where the vibrator bearing is incorporated in the vibrator. .

  The inventors have incorporated a vibration body bearing into a vibration body, and when the shape of the vibration body bearing is deformed into a non-circular shape following the shape of the vibration body, the central portion of the cross section of the outer ring is outward in the axial direction of the outer ring. Deforms into an overhanging arcuate shape, and the amount of deformation (including the concept of deformed shape) is such a size that it cannot be absorbed even when normal crowning is applied to the rollers. Or I found out that it was a shape. For this reason, the end of the roller in the axial direction hits the inner peripheral surface of the deformed outer ring, and the load from the outer ring concentrates on that part, and the roller is inclined to become stable with respect to this load, Skew has occurred.

  Therefore, in the present invention, a gap that increases toward the end in the axial direction of the roller is provided between the roller and the outer ring before the vibration generator bearing is incorporated into the vibration generator, and the size of the gap is large. The amount of deformation of the outer ring in a state where the vibration body bearing is incorporated in the vibration body is set to be greater than the deformation amount. That is, in the present invention, a clearance that allows the amount of deformation is provided in advance in anticipation of the amount of deformation of the outer ring in which the vibration body bearing is incorporated in the vibration body. Thereby, even if the outer ring is deformed, it is possible to prevent a local load from being generated at the end portion of the roller, and thus it is possible to prevent the roller from being skewed. When no local load is generated at the end of the roller, the size of the gap may be exactly the same as the deformation amount of the outer ring.

  The present invention includes a vibrator, a cylindrical external gear that is arranged on the outer periphery of the vibrator and has a flexibility that is bent and deformed by the rotation of the vibrator, the vibrator, A vibration body bearing having a roller rotatably supporting the external gear and an outer ring provided on the outer side of the external gear, and a rigidity with which the external gear meshes internally. In the flexibly meshing gear device provided with the internal gear, between the roller and the outer ring before the vibration generator bearing is incorporated in the vibration generator, the axial end of the roller is provided. It can also be considered that a gap that increases toward the roller is provided, and the length of the gap in the axial direction of the roller is 50 times or less than the length of the gap in the radial direction of the roller.

  According to the present invention, skew is prevented while using a roller for a vibration body bearing, and transmission torque loss can be reduced.

The disassembled perspective view which shows an example of the whole structure of the bending meshing type gear apparatus which concerns on 1st Embodiment of this invention. Similarly sectional drawing which shows an example of whole composition A front view (A) and a cross-sectional view (B) showing the vibrator as well Sectional drawing which shows the outline of the state of the clearance gap of the vibration body bearing before incorporating a vibration body bearing into a vibration body Similarly, a cross-sectional view (A) of a vibration body bearing before the vibration body bearing is incorporated into the vibration body, and a cross-sectional view (B) of the vibration body bearing in a state where it is incorporated. Sectional view (A) of the vibration body bearing before incorporating the vibration body bearing into the vibration body according to the second embodiment of the present invention and cross section (B) of the vibration body bearing in the assembled state Sectional view (A) of the vibration body bearing before incorporating the vibration body bearing into the vibration body according to the prior art, and cross section (B) of the vibration body bearing in the assembled state

  Hereinafter, an example of the first embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 4, the state of the clearance of the vibration body bearing is exaggerated so as to be understood.

  First, the overall configuration of the present embodiment will be schematically described.

  As shown in FIGS. 1, 2, and 4, the flexure meshing gear device 100 is arranged so as to be bent and deformed by the rotation of the vibrating body 104 and the vibrating body 104. Cylinder-shaped external gears 120A and 120B (120) having a roller, and rollers 116A and 116B that rotatably support the external gear 120 between the vibrating body 104 and the external gear 120, and outside the 116A and 116B. Vibration generator bearings 110A and 110B (110) having outer rings 118A and 118B provided on the inner ring, a reduction internal gear 130A (internal gear) having rigidity with which the external gear 120A meshes internally, and a reduction gear And an output internal gear 130B (internal gear) that is provided in parallel with the internal gear 130A and has rigidity to internally mesh with the external gear 120B. Further, between the rollers 116A and 116B and the outer rings 118A and 118B before the vibration body bearing 110 is incorporated into the vibration body 104, the diameter increases in the axial direction O of the rollers 116A and 116B (radial direction). Gap) Gp is provided. The size of the gap Gp is set to be equal to or greater than the deformation amount (radial deformation amount) of the outer rings 118A and 118B in a state where the vibration body bearing 110 is incorporated in the vibration body 104. If no local load is generated at the ends of the rollers 116A and 116B, the size of the gap Gp may be exactly the same as the deformation amount of the outer rings 118A and 118B. In other words, the deformation amount here means that the deformation of the end of the outer ring 118A, 118B is not restricted by the rollers 116A, 116B, and the end of the outer ring 118A, 118B can be freely deformed. This is the amount of deformation of the outer rings 118A and 118B in a state where the vibrator bearing 110 is incorporated.

  Hereinafter, each component will be described in detail.

  As shown in FIGS. 2 and 3, the vibrating body 104 has a substantially columnar shape. More specifically, the vibrating body 104 has a meshing range FA with a constant curvature radius r1 centered on an eccentric position (eccentricity L), and has a shape in which a plurality of curvature radii are combined. The vibrating body 104 is configured to realize a meshing state between the external gears 120A and 120B, the reduction internal gear 130A, and the output internal gear 130B in the meshing range FA. The vibrator 104 is formed with an input shaft hole 106 into which an input shaft (not shown) is inserted at the center. A keyway 108 is provided in the input shaft hole 106 so that the vibrator 104 rotates integrally with the input shaft when the input shaft is inserted and rotated.

  As illustrated in FIG. 2, the vibration body bearing 110 is a bearing disposed between the outside of the vibration body 104 and the inside of the external gear 120. As shown in FIG. 2, the vibrator bearing 110A (110B) includes an inner ring 112, a cage 114A (114B), rollers 116A (116B) as rolling elements, and an outer ring 118A (118B). The inner ring 112 is integrated with the vibration body bearings 110A and 110B, is disposed in contact with the outer periphery of the vibration body 104, and is in contact with the rollers 116A and 116B. The rollers 116A (116B) are rotatably held by the cage 114A (114B). The rollers 116A (116B) may have a cylindrical shape and include a needle shape. The outer ring 118A (118B) is disposed outside the rollers 116A (116B). The outer ring 118A (118B) is bent and deformed by the rotation of the vibrating body 104, and deforms the external gear 120A (120B) disposed outside the outer ring 118A (118B).

  Here, the vibration body bearing 110 in a state before being incorporated in the vibration body 104 will be described. Since the vibration body bearings 110A and 110B have the same shape except for the position in the axial direction O, only the vibration body bearing 110A will be described below with reference to FIG. 4, and description of the vibration body bearing 110B will be omitted. To do. In FIG. 4, the retainer 114A is omitted.

  As shown in FIG. 4, a gap Gp is provided between the roller 116 </ b> A and the outer ring 118 </ b> A that increases toward the ends (both ends) of the roller 116 </ b> A in the axial direction O. The gap Gp is formed by making the diameter r2 of the end portion in the axial direction O of the roller 116A smaller than the diameter r3 of the central portion. Regarding the gap Gp, the length Ln of the gap Gp in the axial direction O of the roller 116A is 50 times or less (the ratio Ln / Dp ≦ 50) the length Dp of the gap Gp in the radial direction R of the roller 116A. Specifically, for example, when the length of the roller 116A in the axial direction O is about 8 mm and the length Ln is 2 mm, the length Dp is 40 μm or more.

  Before the vibration body bearing 110A is incorporated in the vibration body 104, as shown in FIGS. 4 and 5A, the outer ring 118A extends in parallel with the axial direction O. A gap Gp is formed between 116A and 116A. When the vibration body bearing 110A is incorporated in the vibration body 104, as shown in FIG. 5 (B), it is deformed into an arcuate shape in which the central portion of the cross section of the outer ring 118A projects outward in the axial direction O. At this time, the outer ring 118A is simply deformed so that the gap Gp is eliminated or reduced without being biased, and generation of a load concentrated on the local portion (end) of the roller 116A due to the deformation of the outer ring 118A is avoided. In FIG. 5B, it is described that a gap is formed between the outer ring 118A and the center part of the roller 116A, but the outer ring 118A and 116A are in contact with each other at the center part. Has been.

  As shown in FIGS. 1 and 2, the external gear 120 has a cylindrical shape including a base member 122 and external teeth 124. The base member 122 is a flexible cylindrical member and is disposed outside the vibration body bearing 110. As shown in FIG. 2, the external teeth 124 (124 </ b> A, 124 </ b> B) are divided in the axial direction O, but the base member 122 that supports each is integrated and shared. The tooth profile of the external tooth 124 is determined based on the trochoid curve so as to realize theoretical meshing.

  The reduction internal gear 130A is formed of a rigid member, as shown in FIG. The internal gear 130A for reduction has a number of teeth that is i (i = 2, 4,...) Greater than the number of teeth of the external teeth 124A of the external gear 120A. A casing (not shown) is fixed to the reduction internal gear 130A via a bolt hole 132A. And the internal gear 130A for deceleration contributes to the deceleration of rotation of the vibration body 104 by meshing with the external gear 120A. The internal teeth 128A of the reduction internal gear 130A are shaped so as to theoretically mesh with the external teeth 124A based on the trochoid curve.

  On the other hand, as shown in FIG. 2, the output internal gear 130B is also formed of a rigid member, like the reduction internal gear 130A. The output internal gear 130B has the same number of teeth of the internal teeth 128B as the number of teeth of the external teeth 124B of the external gear 120B (constant speed transmission). Note that an output shaft (not shown) is attached to the output internal gear 130B via a bolt hole 132B, and the same rotation as the rotation of the external gear 120B is output to the outside.

  Next, operation | movement of the bending meshing type gear apparatus 100 is demonstrated using FIG. 2, FIG.

  When the vibration generator 104 is rotated by rotation of an input shaft (not shown), the external gear 120 is bent and deformed via the vibration generator bearing 110 according to the rotation state (that is, the external gear 120B is external gear). It bends and deforms in the same phase as 120A).

  When the external gear 120 is bent and deformed by the vibrating body 104, the external teeth 124 move radially outward in the meshing range FA and mesh with the internal teeth 128 of the internal gear 130.

  At the time of meshing, the vibration body bearings 110A and 110B are respectively a portion supporting the external teeth 124A and a portion supporting the external teeth 124B in the axial direction O. For this reason, each of the skew of the roller 116B caused by the meshing between the reduction internal gear 130A and the external tooth 124A, and the skew of the roller 116A caused by the meshing between the output internal gear 130B and the external tooth 124B, respectively. Is prevented.

  In the axial direction O, the external teeth 124 are divided into a portion meshing with the reduction internal gear 130A (external teeth 124A) and a portion meshing with the output internal gear 130B (external teeth 124B). For this reason, when the external gear 120A meshes with the reduction internal gear 130A, even if the external teeth 124B are deformed, the deformation does not cause the external teeth 124A to be deformed. Similarly, when the external gear 120B meshes with the output internal gear 130B, even if the external teeth 124A are deformed, the external teeth 124B are not deformed by the deformation. That is, by dividing the external teeth 124, it is possible to prevent the deformation of one external tooth 124A (124B) from deforming the other external tooth 124B (124A) to deteriorate the meshing relationship.

  The meshing position between the external gear 120 </ b> A and the reduction internal gear 130 </ b> A rotates as the vibration generator 104 rotates. Here, when the vibrating body 104 rotates once, the rotation phase of the external gear 120A is delayed by a difference in the number of teeth from the internal gear 130A for deceleration. That is, the reduction ratio by the reduction internal gear 130A can be obtained as ((the number of teeth of the external gear 120A−the number of teeth of the reduction internal gear 130A) / the number of teeth of the external gear 120A).

  Since both the external gear 120B and the output internal gear 130B have the same number of teeth, the external gear 120B and the output internal gear 130B do not move with each other, and the same teeth can move. Will be engaged. For this reason, the same rotation as the rotation of the external gear 120B is output from the output internal gear 130B. As a result, an output obtained by reducing the rotation of the vibration generator 104 based on the reduction ratio of the internal gear for deceleration 130A can be extracted from the internal gear for output 130B.

  As in the present embodiment, in a flexibly meshing gear device that includes a cylindrical external gear and uses a cylindrical roller for a vibration generator bearing, a vibration generator bearing is incorporated into the vibration generator and is conventionally When the shape of the vibrator bearing is deformed into a non-circular shape following the shape of the vibration generating body, it is deformed into an arcuate shape in which the central portion of the cross section of the outer ring projects outward in the axial direction of the outer ring. This is shown in FIG. FIG. 7A shows a state before the vibration body bearing is incorporated into the vibration body, and FIG. 7B shows a state where the vibration body bearing is incorporated into the vibration body. With the shape of the conventional roller 16A, even if the normal crowning is applied to the roller 16A, the amount of machining or the shape of the crowning is the amount of deformation when the vibrator bearing 10A is incorporated ( Including the concept of deformed shapes). That is, the processing amount or processing shape of the crowning has a size or shape that cannot absorb the deformation amount. For this reason, the end portion Eg in the axial direction O of the roller 16A hits the inner peripheral surface of the deformed outer ring 18A, and the load from the outer ring 18A is concentrated on that portion (end portion Eg). The roller 16A was inclined to cause a skew and a skew occurred. More specifically, since the outer ring 18A and the roller 16A can move in the axial direction O, the balance of the load concentrated on the end portion is lost, a thrust force is generated, and a skew is generated.

  However, in the present embodiment, between the rollers 116A and 116B and the outer rings 118A and 118B before the vibration body bearing 110 is incorporated in the vibration body 104, toward the end in the axial direction O of the rollers 116A and 116B. An increasing gap Gp is provided. The size of the gap Gp is set to be equal to or greater than the deformation amount of the outer rings 118A and 118B in a state where the vibration body bearing 110 is incorporated in the vibration body 104. That is, in the present embodiment, a gap Gp that allows the deformation amount is provided in advance in consideration of the deformation amount of the outer rings 118A and 118B in the state where the vibration body bearing 110 is incorporated in the vibration body 104. is there. As a result, even if the outer rings 118A and 118B are deformed, local load can be prevented from being generated at the ends of the rollers 116A and 116B, so that the skew of the rollers 116A and 116B can be prevented. If no local load is generated at the ends of the rollers 116A and 116B, the size of the gap Gp may be exactly the same as the deformation amount of the outer rings 118A and 118B.

  In this embodiment, as shown in FIGS. 4, 5A, and 5B, the diameter r2 of the end portions of the rollers 116A and 116B in the axial direction O is the central portion of the rollers 116A and 116B in the axial direction O. Is smaller than the diameter r3. That is, the above-described gap Gp can be provided by forming the rollers 116A and 116B accordingly. For this reason, the gap Gp can be provided easily and accurately.

  That is, in this embodiment, skew is prevented while using the rollers 116A and 116B for the vibration body bearing 110, and loss of transmission torque can be reduced.

  Although the present invention has been described with reference to the first embodiment, the present invention is not limited to the first embodiment. That is, it goes without saying that improvements and design changes can be made without departing from the scope of the present invention.

  For example, in the first embodiment, the diameter r2 of the end portions in the axial direction O of the rollers 116A and 116B is smaller than the diameter r3 of the central portion in the axial direction O of the rollers 116A and 116B. Accordingly, the gap Gp is provided, but the present invention is not limited to this. For example, the second embodiment shown in FIGS. 6A and 6B may be used. FIG. 6A shows a state before the vibration body bearing is incorporated into the vibration body, and FIG. 6B shows a state where the vibration body bearing is incorporated into the vibration body. 6A and 6B, only the vibration body bearing 210A is shown, but only the vibration body bearing 210A will be described for the same reason as in FIGS. 5A and 5B. By doing. Also, the cage is not shown in FIGS. 6 (A) and 6 (B).

  In the second embodiment, the thickness t2 of the end portions in the axial direction O of the outer rings 218A and 218B is smaller than the thickness t3 of the central portion in the axial direction O of the outer rings 218A and 218B. Specifically, the inner diameter of the end of the outer ring 218A, 218B is larger than the inner diameter of the central part in the axial direction O. That is, as shown in FIG. 6A, the gap Gp is provided on the inner peripheral surface side of the outer ring 218A facing the roller 216A. For this reason, in the state where the vibration body bearing 210A is incorporated in the vibration body 204, the inner peripheral surface of the outer ring 218A bends along the axial direction O as shown in FIG. However, the inner peripheral surface of the outer ring 218A is bent only to the extent that it is parallel to the axial direction O, and the outer ring 218A can be avoided from hitting the end of the roller 216A locally.

  In the above embodiment, the outer ring or the end of the roller is made smaller (thinner) than the central part for providing the gap Gp. However, the present invention is not limited to this, and the outer ring and the roller Both of the end portions may be made smaller (thinner) than the respective central portions, and the gap Gp may be provided.

  Moreover, in the said embodiment, although it was set as the tooth profile based on the trochoid curve for the external tooth, this invention is not limited to this. The external teeth may be arc teeth or other teeth.

  Further, in the above embodiment, the cylindrical flexure meshing gear device having the reduction internal gear and the output internal gear is shown, but the present invention is not limited to this, and the internal gear is not limited to this. The present invention can also be applied to one so-called cup-type or top-hat type flexure meshing gear device.

  Further, in the first embodiment, the outer diameters of the rollers 116A and 116B change in a curve from the central part to the end part of the rollers 116A and 116B in the axial direction O, but the present invention is not limited to this. The outer diameter of the roller may be linearly changed in the axial direction O from the center to the end of the roller.

  In the second embodiment, the inner diameters of the outer rings 218A and 218B are changed in a curve from the central part to the end part of the outer rings 218A and 218B in the axial direction O. However, the present invention is not limited to this, and the outer ring The inner diameter of the outer ring may be linearly changed in the axial direction O from the center to the end of the outer ring.

  The present invention is widely applicable to a flexure meshing gear device.

4, 104, 204: Exciter 10A, 110, 110A, 110B, 210A ... Exciter bearings 12, 112, 212 ... Inner ring 16A, 116A, 116B, 216A ... Rollers 18A, 118A, 118B, 218A, 218B ... Outer ring DESCRIPTION OF SYMBOLS 100 ... Flexibly meshing gear apparatus 114A, 114B ... Cage 120, 120A, 120B ... External gear 122 ... Base member 124, 124A, 124B ... External tooth 128, 128A, 128B ... Internal tooth 130 ... Internal gear 130A ... Reduction internal gear 130B ... Output internal gear 132A, 132B ... Bolt hole

Claims (4)

An exciter, a cylindrical external gear having flexibility that is arranged on the outer periphery of the exciter and is bent and deformed by the rotation of the exciter, and the exciter and the external gear A vibration body bearing having a roller rotatably supporting the external gear and an outer ring provided on the outside of the roller, an internal gear having rigidity with which the external gear meshes internally, In a flexibly meshing gear device comprising:
A gap increasing toward the axial end of the roller is provided between the roller and the outer ring before the vibration generator bearing is incorporated into the vibration generator,
The size of the gap is set to be equal to or greater than the deformation amount of the outer ring in a state where the vibration body bearing is incorporated in the vibration body. An exciter, a cylindrical external gear having flexibility that is arranged on the outer periphery of the exciter and is bent and deformed by the rotation of the exciter, and the exciter and the external gear A vibration body bearing having a roller rotatably supporting the external gear and an outer ring provided on the outside of the roller, an internal gear having rigidity with which the external gear meshes internally, In a flexibly meshing gear device comprising:
A gap increasing toward the axial end of the roller is provided between the roller and the outer ring before the vibration generator bearing is incorporated into the vibration generator,
The length of the gap in the axial direction of the roller is 50 times or less the length of the gap in the radial direction of the roller. In claim 1 or 2,
A flexure meshing gear device, wherein a diameter of an end portion in the axial direction of the roller is smaller than a diameter of a central portion in the axial direction of the roller. In any one of Claims 1 thru | or 3,
An inner diameter of an end portion in the axial direction of the outer ring is made larger than an inner diameter of a central portion in the axial direction of the outer ring.

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