JP2017125596A - Wave gear transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave gear transmission device which can alleviate the stress of a flexible outer gear.SOLUTION: A wave gear transmission device 1 comprises a pair of rigid inner gears 2 and 3 having a plurality of inner teeth 21 and 31 at internal peripheries, and a flexible outer gear 4 having a plurality of outer teeth 41 at an external periphery. Wave motion generators 5 and 6 provided inside the flexible outer gear 4 make the flexible outer ring gear 4 partially engage with the pair of rigid inner gears 2 and 3 by elliptically bending the same. The flexible outer gear 4 includes a plurality of elements 50 which are aligned in a peripheral direction, and form the outer teeth 41, and a flexible annular connecting member 60 which connects and supports the plurality of elements 50 at tooth bottoms of the outer teeth 41.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flat type (pancake type) wave gear transmission device.

  There has been proposed a flat type (pancake type) wave gear transmission device in which a so-called flat type (pancake type) flexible external gear meshes with a pair of rigid internal gears having a difference in the number of teeth. (For example, refer to Patent Document 1).

JP-A-2-221740

  A tooth motion generator is disposed inside the flexible external gear. The flexible external gear is bent in an elliptical shape by a wave generator. In order to bend into an ellipse, the flexible external gear is formed thin. In such a thin flexible external gear, the bottom portion of the external teeth meshing with the internal teeth is elastically deformed so as to be extended by receiving the meshing pressure. For this reason, a high stress is generated in the tooth bottom portion.

  The objective of this invention is providing the wave gear transmission which can relieve | moderate the stress of a flexible external gear.

  The invention of claim 1 can be provided with a pair of rigid internal gears (2, 3) arranged on the same axis and having a plurality of internal teeth (21, 31) on the inner periphery and a plurality of external teeth (41) on the outer periphery. The flexible external gear (4) is arranged inside the flexible external gear, and the flexible external gear is bent into an elliptical shape so as to partially mesh with the pair of rigid internal gears. A wave generator (5, 6) for moving the position in the circumferential direction, wherein the flexible external gear is arranged in the circumferential direction of the flexible external gear to form external teeth (50) And a flexible annular connecting member (60) that connects and supports the plurality of elements at the bottom of the external teeth.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
According to a second aspect of the present invention, each of the elements has a closed end (70b) in the middle of the tooth width direction from an open end (70a) at both ends in the tooth width direction (W) of the tooth bottom portion (41a) of the external tooth. A pair of insertion grooves (70) extending to the tooth thickness direction (T) and the annular coupling member may include a pair of annular coupling members respectively inserted into the pair of insertion grooves.

As in claim 3, each of the elements includes a pair of split elements (51, 52) that are combined in the tooth thickness direction (T) to form a single external tooth, and a pair of the pair of split elements The mating surfaces (73, 74) may be connected by uneven engagement.
According to a fourth aspect of the present invention, the pair of split elements include a pair of tooth surfaces (71, 72) inclined in opposite directions, and the concave and convex engagement connects the pair of mating surfaces at the tooth bottom. The pair of split elements may be elastically deformable so that the pair of mating surfaces are separated from each other on the tooth tip side.

  The element may be made of resin, and the annular connecting member may be formed by a plurality of annular steel plates (61) arranged in a stacked manner.

In the first aspect of the invention, when the external teeth of the flexible external gear are subjected to the reaction force of meshing with the internal teeth, the flexible annular connecting member is bent to displace the elements forming the external teeth. It becomes easy to do. For this reason, the stress of a flexible external gear can be relieved.
In the second aspect of the invention, in the flexible external gear, the plurality of elements can be stably connected and supported by the pair of annular connecting members inserted into the pair of insertion grooves of each element.

In the invention of claim 3, in the flexible external gear, a pair of split elements can be connected by concave and convex engagement to form a single external tooth.
In the invention of claim 4, the pair of split elements having the respective tooth surfaces of the external teeth are elastically deformed so that the mating surfaces are separated from each other on the tooth tip side, whereby the meshing rate of the external teeth with respect to the internal teeth is increased. Can be improved.

  In invention of Claim 5, durability can be improved by using the some cyclic | annular steel plate laminated | stacked and arrange | positioned as an annular connection member, achieving weight reduction by making an element into resin.

It is a schematic sectional drawing of the wave gear transmission device of one Embodiment of this invention. It is a schematic diagram when a flexible external gear is bent from a circle to an ellipse and meshes with a corresponding rigid internal gear. It is a side view of a flexible external gear. It is a disassembled perspective view of the element which forms the external tooth of a flexible external gear. It is a typical side view of the principal part of a flexible external gear. It is a typical side view of the principal part of a flexible external gear.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of a wave gear transmission device according to an embodiment of the present invention. As shown in FIG. 1, the wave gear transmission device 1 includes a first rigid internal gear 2, a second rigid internal gear 3, a flexible external gear 4, a first wave generator 5, and a second wave generation. The device 6 includes an input shaft 7, a first member 8, a second member 9, a cross roller bearing 10, a first bearing 11, and a second bearing 12. The wave gear transmission device 1 is used for a speed reducer or a speed increaser.

The first rigid internal gear 2 has an annular shape, and a plurality of first internal teeth 21 are formed on the inner peripheral surface. The second rigid internal gear 3 has an annular shape, and a plurality of second internal teeth 31 are formed on the inner peripheral surface.
The flexible external gear 4 is a flat type (pancake type). The flexible external gear 4 is disposed inside the first rigid internal gear 2 and the second rigid internal gear 3. The flexible external gear 4 has a plurality of external teeth 41 that are arranged in the circumferential direction of the outer periphery and mesh with the first internal teeth 21 and the second internal teeth 31.

The input shaft 7 constitutes a rotation input element that is connected and fixed to a rotation source such as an output shaft of the motor. Further, the first rigid internal gear 2 constitutes a non-rotatable element that is restrained by the first member 8 so as not to rotate. The second rigid internal gear 3 is formed integrally with the second member 9 and constitutes a reduced speed rotation output element.
The first member 8 and the second member 9 are annular members, and the central axes of the first member 8 and the second member 9 coincide with the device axis 1a.

The input shaft 7 extends so that the centers of the first member 8 and the second member 9 are inserted in the direction of the device axis 1a. The input shaft 7 is rotatably supported by the first member 8 and the second member 9 via the first bearing 11 and the second bearing 12, respectively. The 1st bearing 11 and the 2nd bearing 12 consist of ball bearings, for example.
The first rigid internal gear 2 includes an annular portion 22 having a plurality of first internal teeth 21 formed on the inner peripheral surface, and an extending portion 23 extending radially outward from one end of the annular portion 22. .

The first member 8 includes a pair of members 81 and 82 that are separated from each other in the direction of the apparatus axis 1a. The extending portion 23 of the first rigid internal gear 2 is sandwiched between the pair of members 81 and 82 with respect to the direction of the device axis 1a. For this reason, the 1st rigid internal gear 2 is restrained so that rotation is impossible.
A pair of members 81 and 82 of the first member 8 and the first rigid internal gear 2 are fastened to each other by a fixing screw 13. A plurality of fixing screws 13 are provided at regular intervals in the circumferential direction of the first member 8.

The first bearing 11 is interposed between the inner peripheral surface of the boss portion 83 formed at the radially inner end of one member 81 of the first member 8 and the outer peripheral surface 7 a at one end in the axial direction X of the input shaft 7. doing. The second rigid internal gear 3 is disposed radially inward of the other member 82 of the first member 8.
The second rigid internal gear 3 includes an annular portion 32 having a plurality of second internal teeth 31 formed on the inner peripheral surface, an extending portion 33 extending radially inward from one end of the annular portion 32, and an extended portion. And a boss portion 34 formed at the radially inner end of the installation portion 33.

The second bearing 12 is interposed between the inner peripheral surface of the boss portion 34 of the second rigid internal gear 3 and the outer peripheral surface 7 b at the other end in the axial direction X of the input shaft 7. The boss portion 34 of the second rigid internal gear 3 is integrally connected to one end of the cylindrical second member 9.
The cross roller bearing 10 is interposed between the inner peripheral surface 82a of the other member 82 of the first member 8 and the outer peripheral surface 9a of the second member 9 in the radial direction. The cross roller bearing 10 includes an outer ring 14, an inner ring 15, and a roller 16.

The outer ring 14 of the cross roller bearing 10 is fixed to the inner peripheral surface 82 a of the other member 82 of the first member 8. For this reason, the outer ring | wheel 14 is restrained so that rotation is impossible. The inner ring 15 of the cross roller bearing 10 is connected to the outer peripheral surface 9a of the second member 9 so as to be integrally rotatable.
The first wave generator 5 and the second wave generator 6 are arranged coaxially and spaced apart in the axial direction. The first wave generator 5 is disposed inside the flexible external gear 4 inside the first rigid internal gear 2. The second wave generator 6 is disposed inside the flexible external gear 4 inside the second rigid internal gear 3.

The first wave generator 5 and the second wave generator 6 bend the corresponding axial region of the flexible external gear 4 into an ellipse, and are partially flexible at two points of the major axis of the ellipse. The external gear 4 is engaged with the corresponding rigid internal gears 2 and 3. The first wave generator 5 and the second wave generator 6 have the same configuration.
FIG. 2 is a schematic view when the flexible external gear 4 is bent from a circle to an ellipse and meshes with the corresponding rigid internal gears 2 and 3. As shown in FIGS. 2 and 3, each wave generator 5, 6 includes a bearing 91 and an elliptical cam 92. The bearing 91 has flexibility. The cam 92 is disposed on the inner peripheral side of the bearing 91. The cam 92 elastically deforms the bearing 91 toward the outer peripheral side.

Bearing 91 includes an inner ring 93, an outer ring 94, a plurality of balls 95, and a retainer (not shown). The inner ring 93 and the outer ring 94 are flexible. The ball 95 is sandwiched between the inner ring 93 and the outer ring 94 so as to be able to rotate and revolve.
The retainer is configured to hold the balls 95 apart from each other. The bearing 91 has a perfect circle shape when the cam 92 is not provided.

The cam 92 is formed integrally with the outer peripheral surface 7 c of the intermediate portion in the axial direction X of the input shaft 7. The cam 92 may be fixed to the outer peripheral surface 7c of the intermediate portion in the axial direction X of the input shaft 7 by screwing or the like.
The major diameter of the cam 92 is set larger than the inner diameter of the inner ring 93 of the bearing 91, and the minor diameter of the cam 92 is set smaller than the inner diameter of the inner ring 93. For this reason, the cam 92 is disposed on the inner peripheral side of the inner ring 93, thereby pressing the inner ring 93 toward the outer peripheral side at two locations of the long diameter portion to elastically deform the inner ring 93 into an elliptical shape. As the cam 92 rotates, the major axis portion rotates and the elastically deformed inner ring 93 rotates integrally with the cam 92.

The outer ring 94 is fixed to the inner peripheral side of the flexible external gear 4 and rotates integrally with the flexible external gear 4. Since the inner ring 93 and the outer ring 94 can rotate independently, the inner ring 93 rotates integrally with the rotation of the cam 92, and the outer ring 94 is bent into an oval shape by the inner ring 93.
FIG. 3 is a side view of the flexible external gear. As shown in FIG. 3, the flexible external gear 4 includes a plurality of elements 50 and a pair of flexible annular coupling members 60 that couple the plurality of elements 50. The element 50 is made of resin. Each annular connecting member 60 is formed by a plurality of annular steel plates 61 arranged in a stacked manner.

Since each of the plurality of annular steel plates 61 is thinner than the case where a single annular steel plate is used as the annular coupling member 60, the annular coupling member 60 is easily bent in the radial direction. Moreover, the tensile strength of the circumferential direction Y as a whole of the some annular steel plate 61 is equivalent to the tensile strength of a single annular steel plate.
The elements 50 are arranged in the circumferential direction Y of the flexible external gear 4 and each form a single external tooth 41. The annular connecting member 60 connects and supports a plurality of elements 50 at the tooth bottom portion 41 a of the external tooth 41.

FIG. 4 is an exploded perspective view of the element 50. As shown in FIGS. 3 and 4, each element 50 includes a pair of block-shaped split elements 51 and 52 that are combined in the tooth thickness direction T to form a single external tooth 41.
Each element 50 (that is, the divided elements 51 and 52) includes a pair of insertion grooves 70 that are inserted in the tooth thickness direction T. The pair of insertion grooves 70 extend from the open ends 70 a at both ends in the tooth width direction W to the closed ends 70 b in the middle in the tooth width direction W at the root portion 41 a of the external tooth 41. The corresponding annular connecting members 60 are inserted through the pair of insertion grooves 70.

The pair of split elements 51, 52 have a pair of tooth surfaces 71, 72 that are inclined in opposite directions with respect to the toothing direction H, and a pair of mating surfaces 73, 74 that face each other. The pair of mating surfaces 73 and 74 are opposed to the tooth thickness direction T.
The pair of mating surfaces 73 and 74 are connected by concave and convex engagement, whereby the pair of split elements 51 and 52 are connected to each other. Specifically, a convex portion 75 a and a concave portion 75 b are provided on the mating surface 73 of one split element 51. On the mating surface 74 of the other split element 52, there are provided a concave portion 76a that is unevenly fitted to the convex portion 75a, and a convex portion 76b that is unevenly fitted to the concave portion 75b.

  The convex portions 75a and 76b and the concave portions 75b and 76a that achieve the concave-convex engagement with the pair of mating surfaces 73 and 74 are disposed on the tooth bottom portion 41a. As shown in FIG. 5, the pair of split elements 51 and 52, in which the mating surfaces 73 and 74 are connected to each other at the tooth bottom 41a, separate the mating surfaces 73 and 74 on the tooth tip side. It can be elastically deformed. Thereby, the meshing rate of the external tooth 41 with respect to the internal tooth 21 (31) can be improved. Further, the meshing backlash can be brought close to zero.

  In addition, as shown in FIG. 4, the element 50 has a structure for connecting to an element 50 (not shown) adjacent to both sides of the element 50. Specifically, one split element 51 has a convex portion 77 a and a concave portion 77 b on the side surface 73 a opposite to the mating surface 73. The other split element 52 has a concave portion 78 a and a convex portion 78 b on the side surface 74 a opposite to the mating surface 74.

  The opposite side surface 73a (the convex portion 77a and the concave portion 77b) of one split element 51 is opposite to the opposite side surface 74a (the concave portion 78a and the convex portion 78b) of the other split element 52 of the element 50 (not shown) adjacent to the opposite side surface 73a. Engage with irregularities. Thereby, the opposite side surface 73a of one division element 51 is connected to the opposite side surface 74a of the other division element 52 of the adjacent element 50 (not shown).

  The opposite side surface 74a (the concave portion 78a and the convex portion 78b) of the other split element 52 is opposite to the opposite side surface 73a (the convex portion 77a and the concave portion 77b) of one split element 51 of the element 50 (not shown) adjacent to the opposite side surface 74a. Engage with irregularities. Thereby, the opposite side surface 74a of the other split element 52 is connected to the opposite side surface 73a of one split element 51 of the adjacent element 50 (not shown).

  The pair of split elements 51 and 52 are formed in the same shape so as to share parts. That is, the convex portion 77a and the concave portion 77b of one split element 51 are arranged in this order on one side in the tooth width direction W, and the concave portion 78a and the convex portion 78b of the other split element 51 are arranged in one side in the tooth width direction W. They are lined up in this order. When the direction of one split element 51 is changed and one split element 51 is used as the other split element 52, the convex portion 77a and the concave portion 77b of one split element 51 are the convex portion 78b of the other split element 52. And used as a recess 78a. The same applies to the relationship between the convex portions 75a and concave portions 75b of one split element 51 and the convex portions 76b and concave portions 76a of the other split element 52.

The common use of the pair of split elements 51 and 52 makes it easy to manage the parts, and the assembly of the flexible external gear 4 is simple and easy to manufacture.
According to the present embodiment, as shown in FIG. 6, when the external tooth 41 of the flexible external gear 4 receives a reaction force of meshing with the internal tooth 21 or 31, the flexible annular connecting member 60. The element 50 forming the external teeth 41 is easily displaced by bending. For this reason, the stress of the flexible external gear 4 can be relieved. Thereby, the durable life of the flexible external gear 4 can be lengthened, and hence the durable life of the wave gear transmission device 1 can be lengthened.

  As shown in FIG. 4, each element 50 has a pair of insertion grooves 70 extending from both ends in the tooth width direction W to the middle part in the tooth width direction W in the tooth bottom portion 41 a of the external teeth 41 and inserted in the tooth thickness direction T. Have. Therefore, as shown in FIG. 3, a plurality of elements 50 are formed by a pair of annular connecting members 60 inserted from both sides in the tooth width direction W into the pair of insertion grooves 70 of each element 50 (the divided elements 51 and 52). Can be stably connected and supported.

Moreover, the single external tooth | gear 41 can be formed by connecting the mating surfaces 73 and 74 of a pair of division | segmentation elements 51 and 52 by uneven | corrugated engagement (concavo-convex fitting).
Moreover, the weight reduction of the flexible external gear 4 and by extension, the wave gear transmission apparatus 1 can be achieved by making the element 50 resin. Moreover, durability can be improved, allowing the displacement of the resin-made element 50 by comprising the cyclic | annular connection member 60 by the some cyclic | annular steel plate 61 laminated | stacked and arrange | positioned.

  The present invention is not limited to the above embodiment, and a single external tooth may be formed by a single element without using a split element. Two adjacent external teeth may be formed by a single element. In addition, the present invention can be variously modified within the scope of the claims.

  DESCRIPTION OF SYMBOLS 1 ... Wave gear transmission device, 2 ... 1st rigid internal gear, 3 ... 2nd rigid internal gear, 4 ... Flexible external gear, 5 ... 1st wave generator, 6 ... 2nd wave generator, 21 ... 1st DESCRIPTION OF SYMBOLS 1 Internal tooth, 31 ... 2nd internal tooth, 41 ... External tooth, 41a ... Tooth bottom part, 50 ... Element, 51, 52 ... Dividing element, 60 ... Annular connection member, 61 ... Annular steel plate, 70 ... Insertion groove, 70a ... Open end, 70b ... closed end, 71, 72 ... tooth surface, 73, 74 ... mating surface, 75a ... convex part, 75b ... concave part, 76a ... concave part, 76b ... convex part, 91 ... bearing, 92 ... cam, 93 ... Inner ring, 94 ... outer ring, 95 ... ball, H ... toothpaste direction, T ... tooth thickness direction, W ... tooth width direction, X ... axial direction, Y ... circumferential direction

Claims (5)

A pair of rigid internal gears arranged on the same axis and having a plurality of internal teeth on the inner periphery;
A flexible external gear having a plurality of external teeth on the outer periphery;
Wave generation that is arranged inside the flexible external gear, flexes the flexible external gear in an elliptical shape, partially meshes with the pair of rigid internal gears, and moves the meshing position in the circumferential direction And equipped with
The flexible external gear includes a plurality of elements that are arranged in the circumferential direction of the flexible external gear to form external teeth, and a flexible ring that connects and supports the plurality of elements at the bottom of the external teeth. A wave gear transmission device including a connecting member. 2. The element according to claim 1, wherein each of the elements includes a pair of insertion grooves that extend from the open ends at both ends in the tooth width direction to the closed ends in the middle of the tooth width direction in the tooth bottom portion of the external teeth and are inserted in the tooth thickness direction. Including
The annular gearing device is a wave gear transmission device including a pair of annular coupling members respectively inserted into the pair of insertion grooves. In Claim 1 or 2, each said element includes a pair of division elements which are combined with each other in the tooth thickness direction to form a single external tooth,
A wave gear transmission device in which a pair of mating surfaces of the pair of split elements are connected by concave-convex engagement. In Claim 3, the pair of split elements includes a pair of tooth surfaces inclined in opposite directions,
The concavo-convex engagement connects the pair of mating surfaces at the root part,
The pair of split elements are wave gear transmissions that can be elastically deformed so that the pair of mating surfaces are separated from each other on the tooth tip side. In any one of Claims 1-4, the said element is resin,
The annular coupling member is a wave gear transmission device formed by a plurality of annular steel plates arranged in a stacked manner.

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