JP2016194315A - Flexspline for wave motion gearing device and wave motion gearing device using flexspline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexspline having a new structure that is sufficiently deformed in an easy manner in regard to a radial input from a wave generator, realizing superior durability and enables its manufacturing to be carried out easily in less-expensive manner, and provide a wave motion gear device using the flexspline.SOLUTION: This invention relates to a flexspline 12 for a wave motion gear device 10. A cylindrical part 24 having outer teeth is constituted by a plurality of pin members 20 supported by a supporting member 18 while being arranged in a peripheral direction and at the same time there is provided holding means 26 for holding pin members 20 at an outer peripheral surface of a wave generator 16. The cylindrical part 24 is pushed wide toward an outer periphery by the wave generator 16 partially on the periphery to cause the pin members 20 to be inclined and engaged with inner teeth 28 of a circular spline 14 and at the same time the pin members 20 at the other portions on the periphery of the cylindrical part 24 are not engaged with the inner teeth 28 of a circular spline 14 by holding means 26, but held at a position spaced apart at the inner periphery.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a flexspline constituting a wave gear device and a wave gear device using the flex spline.

  2. Description of the Related Art Conventionally, a wave gear device is known as a kind of precision reducer used for, for example, driving a robot joint. The wave gear device generally has a structure in which a flexspline is inserted into a circular spline and a wave generator is inserted into the flexspline. In addition, inner teeth arranged in the circumferential direction are formed on the inner circumferential surface of the circular spline, and the flexspline has a cylindrical portion having outer teeth corresponding to the inner teeth in a number different from the inner teeth on the outer circumferential surface. Is provided. The cylindrical portion of the flexspline is elastically deformable in the radial direction, and a wave generator having an outer peripheral surface with a non-circular cross section is inserted into the cylindrical portion, so that the cylindrical portion is The inner teeth of the circular spline and the outer teeth of the flex spline are meshed at the expanding portion of the cylindrical portion by the wave generator.

  Then, with either one of the circular spline or flex spline fixed, the wave generator is rotated by an input from a motor or the like, and the meshing position of the internal and external teeth is sequentially moved on the circumference, A rotational output corresponding to the difference in the number of external teeth and internal teeth can be obtained from either the circular spline or the flexspline. Examples thereof include Japanese Patent No. 5165120 (Patent Document 1) and Japanese Patent Laid-Open No. 5-26305 (Patent Document 2).

  By the way, the flex spline of the wave gear device is required to have a high durability against repeated input as well as being able to be deformed by a relatively small input since the cylindrical portion is repeatedly bent and deformed by the wave generator. Therefore, the conventional flexspline is generally formed of a metal such as nickel-molybdenum steel having excellent toughness.

  However, in a flexspline formed of nickel-molybdenum steel having excellent strength, it is necessary to make the cylindrical portion very thin in order to easily cause elastic deformation of the cylindrical portion. Therefore, the flexspline of the current wave gear device is difficult to manufacture by mold forming that can be easily mass-produced, and it is necessary to cut the forging material with high precision, making it extremely difficult and extremely There was a problem of being expensive.

Japanese Patent No. 5165120 JP-A-5-26305

  The present invention has been made in the background of the above-mentioned circumstances, and its solution is easily deformable with respect to the radial input from the wave generator, exhibits excellent durability, and is manufactured. It is an object of the present invention to provide a flex spline having a novel structure that can be easily obtained at low cost, and a wave gear device using the flex spline.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  That is, the first aspect of the present invention has a cylindrical portion inserted into an annular circular spline having a plurality of internal teeth arranged in the circumferential direction on the inner peripheral surface, and the outer peripheral surface of the cylindrical portion. A plurality of external teeth different in number from the internal teeth are formed side by side in the circumferential direction, and the cylindrical portion is partially outer circumferentially by a wave generator inserted in the cylindrical portion. A flex spline for a wave gear device, wherein the external teeth of the cylindrical portion are configured to be partially meshed with the internal teeth of the circular spline. The cylindrical portion is constituted by a plurality of pin members, and the pin members are supported by the support member side by side in the circumferential direction, while holding means for holding the pin members on the outer peripheral surface of the wave generator The cylinder is provided The pin member is tilted by the wave generator to be partially spread out on the circumference by the wave generator and meshed with the inner teeth of the circular spline. In the portion, the pin member is held by the holding means at a position away from the inner periphery without meshing with the inner teeth of the circular spline.

  According to the flex spline for the wave gear device structured according to the first aspect as described above, the cylindrical portion having the external teeth is constituted by a plurality of pin members supported side by side in the circumferential direction, These pin members are structured to mesh with the internal teeth by tilting. Thus, the cylindrical part provided with the external teeth is not a structure that is continuous in the circumferential direction as in the prior art, but has a structure in which a plurality of pin members are disposed so as to be tilted and displaced substantially independently. . Therefore, the cylindrical portion that can be easily obtained without requiring high-precision molding by cutting can realize partial meshing with the inner teeth, and can also obtain excellent durability. .

  According to a second aspect of the present invention, in the flex spline for the wave gear device described in the first aspect, the holding means is an elastic holding body, and the pin member is The pin member is elastically held on the outer peripheral surface, and the pin member is allowed to tilt by elastic deformation of the elastic holding body.

  According to the second aspect, the tilting of the pin member and the return and holding from the tilted state are easily realized by the elasticity of, for example, rubber, polymer elastomer, spring steel or the like.

  According to a third aspect of the present invention, in the flexspline for the wave gear device described in the second aspect, the elastic holding body is annular, and the elastic holding body is constituted by a plurality of the pin members. Further, it is fitted on the cylindrical part.

  According to the third aspect, the tilting of the pin member and the return and holding from the tilted state can be realized very easily by fitting the annular elastic body to the cylindrical portion. Moreover, since the elastic holding body is separated from the cylindrical part, the pin member constituting the cylindrical part has a special structure and material for realizing tilting and returning and holding from the tilted state. The pin member can be formed more easily.

  According to a fourth aspect of the present invention, in the flexspline for a wave gear device according to any one of the first to third aspects, one end of the pin member in the axial direction is supported by the support member. It is what.

  According to the fourth aspect, the length of the pin member is increased when the pin member is tilted by being pushed outward by the wave generator as compared with the case where the axially intermediate portion of the pin member is supported by the support member. It becomes easy to set the ratio of the amount of tilt displacement to the outer periphery with respect to the outer periphery. Therefore, the partial meshing of the outer teeth and the inner teeth can be achieved with a relatively short pin member, and the flexspline can be downsized in the axial direction.

  According to a fifth aspect of the present invention, in the flexspline for the wave gear device according to the fourth aspect, the support member has a plurality of support holes formed therein, and one axial direction of the pin member is formed. The end portion is inserted and supported in the support hole, and the hole cross-sectional shape of the support hole is increased toward the opening, so that the pin member is allowed to tilt.

  According to the fifth aspect, it is easy to attach the pin member to the support member. In addition, by setting the hole cross-sectional shape of the support hole so as to expand in the tilt direction of the pin member toward the opening, it is possible to easily allow the tilt in the radial direction while positioning the pin member in the circumferential direction of the cylindrical portion. be able to.

  According to a sixth aspect of the present invention, in the flexspline for the wave gear device according to the fifth aspect, the holding means is an elastic holding body, and the elastic holding body is an inner peripheral surface of the support hole. And one end portion in the axial direction of the pin member are elastically supported by the support member.

  According to the sixth aspect, since the elastic holding body is provided between the support hole and the radial direction of the pin member, the pin member is elastically held in a tiltable state, and the pin member is held around the cylindrical portion. It can partially mesh with the internal teeth above. In particular, if the elastic holder is fixed to at least one of the inner peripheral surface of the support hole and the outer peripheral surface of one end of the pin member in the axial direction, the number of parts can be reduced and the assembly work associated therewith can be simplified. Can also be planned.

  According to a seventh aspect of the present invention, in the flex spline for the wave gear device according to any one of the first to sixth aspects, the pin member is supported by the support member so as not to roll. It is.

  According to the 7th aspect, the energy loss by rolling of a pin member is avoided, and the transmission efficiency of force can be improved. Furthermore, noise and vibration can be prevented from being generated by rolling of the pin member, and quietness can be improved.

  According to an eighth aspect of the present invention, in the flexspline for the wave gear device described in the seventh aspect, the pin member has a non-circular cross section.

  According to the eighth aspect, it is possible to select a pin member having a cross-sectional shape other than circular by arranging the pin member so as not to roll, and the pin member having a cross-sectional shape superior in force transmission efficiency and durability. Can be arbitrarily adopted.

  According to a ninth aspect of the present invention, in the flexspline for the wave gear device according to any one of the first to eighth aspects, an inner periphery of the circular spline that is superimposed on an outer peripheral surface of the cylindrical portion. The surface and the outer peripheral surface of the wave generator that overlaps the inner peripheral surface of the cylindrical portion and partially pushes the cylindrical portion to the outer periphery on the periphery correspond to each other with respect to the central axis. It is inclined in the direction.

  According to the ninth aspect, the pin member that is tilted by being pushed to the outer periphery by the wave generator is overlapped over a wide area in the axial direction with respect to the inner peripheral surface of the circular spline having the inner teeth, and the stress distribution As a result, the durability of the pin member and internal teeth can be improved and the torque capacity can be increased accordingly.

  Further, since the outer peripheral surface of the wave generator that tilts the pin member is inclined along the tilted pin member that meshes with the inner teeth, the tilted pin member is axially aligned with the outer peripheral surface of the wave generator. It is held over a wide area and is stably meshed with the internal teeth without rattling.

  According to a tenth aspect of the present invention, in the flex spline for the wave gear device according to any one of the first to ninth aspects, at least one of the pin member and the support member is formed of a synthetic resin. It is what.

  According to the tenth aspect, the flexspline, which has been conventionally made of metal, is made of synthetic resin at least in part, thereby reducing weight and facilitating manufacture. In addition, the pin member and the support member have a relatively low demand for shape and dimensional accuracy as compared with the conventional flex spline, and any of them can be easily formed by injection molding or the like.

  The eleventh aspect of the present invention is provided with a circular spline having an annular shape with internal teeth formed on the inner peripheral surface, and a cylindrical portion of the flexspline is inserted into the inner periphery of the circular spline. A number of external teeth different from the internal teeth of the circular spline are formed on the outer peripheral surface of the cylindrical portion of the flexspline, and a wave generator is inserted on the inner periphery of the flexspline. The cylindrical portion of the flexspline is partially pushed outward on the circumference by the wave generator, and the outer teeth of the portion spread by the wave generator are connected to the inner teeth of the circular spline. In the meshed wave gear device, the flex spline described in any one of the first to tenth aspects is used. That.

  According to the wave gear device having the structure according to the eleventh aspect, the flex spline that is difficult and expensive to manufacture in the conventional wave gear device can be simplified and simplified by the structure according to the present invention. Since it can be manufactured at a low cost, the wave gear device can be manufactured more easily than before and can be provided at a low cost.

  According to the present invention, in the flex spline constituting the wave gear device, the cylindrical portion having the external teeth is constituted by a plurality of pin members supported side by side in the circumferential direction, and the pin members tilt. It is structured to mesh with internal teeth. Thus, the cylindrical part provided with the external teeth is not a structure that is continuous in the circumferential direction as in the prior art, but a structure in which a plurality of pin members are disposed so as to be tilted and displaced substantially independently. Therefore, unlike the conventional flex spline, there is no need to cut the cylindrical portion and form it with high accuracy, and the flex spline can be obtained easily.

The front view which shows the wave gear apparatus as 1st embodiment of this invention. The front view which shows the state which removed the front cover member of the wave gear apparatus shown in FIG. III-III sectional drawing of FIG. IV-IV sectional drawing of FIG. The disassembled perspective view of the wave gear apparatus shown in FIG. The exploded right view of the wave gear apparatus shown in FIG. The perspective view of the flexspline which comprises the wave gear apparatus shown in FIG. The front view of the flexspline shown in FIG. The right view of the flexspline shown in FIG. The perspective view which shows the pin member which comprises the flexspline of the wave gear apparatus as another one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  1-4 show a wave gear device 10 as a first embodiment of the present invention. As shown in FIGS. 5 and 6, the wave gear device 10 includes a flexspline 12, a circular spline 14, and a wave generator 16.

  As shown in FIGS. 7 to 9, the flex spline 12 has a structure in which a plurality of pin members 20 are supported by an annular support member 18, and the pin members 20 are arranged in the circumferential direction over the entire circumference. ing.

  The support member 18 is a hard member formed of a synthetic resin such as ABS resin or a metal such as iron, has a substantially annular shape, and opens in an axial end surface in a radially intermediate portion. A plurality of bottomed support holes 22 are formed on the circumference. The support hole 22 of the present embodiment has a hole cross-sectional area that gradually increases toward the opening side, and the diameter of the support hole 22 is particularly large in the radial direction of the support member 18 as shown in FIG. As a result, the support hole 22 has a substantially circular cross section at the bottom and a substantially oval shape at the opening.

  The pin member 20 is a hard member formed of a synthetic resin, metal, or the like, like the support member 18, and has a substantially cylindrical shape with a small diameter. The pin member 20 has a substantially circular cross section corresponding to the hole cross-sectional shape of the end portion on the bottom side of the support hole 22.

  The pin member 20 has one end in the axial direction inserted into the support hole 22 of the support member 18, and one end in the axial direction is detachably supported by the support member 18. In addition, since the pin member 20 extends in a substantially constant circular cross section in the axial direction, with respect to the opening portion of the support hole 22 having a substantially oval cross section whose cross sectional area is larger than the end portion on the bottom side, At least in the major axis direction, they are separated from the inner circumference. As a result, the pin member 20 can be tilted with respect to the support member 18. In particular, in the present embodiment, tilting in the radial direction of the support member 18 is allowed, while in the circumferential direction of the support member 18. Tilt is limited and the plurality of pin members 20 are positioned relative to each other.

  Further, a plurality of (in this embodiment, 50) pin members 20 are supported by one end portion in the axial direction by the support member 18 and arranged side by side in the circumferential direction. A cylindrical portion 24 is configured by a portion protruding from the 18 support holes 22. Since this cylindrical part 24 is comprised by the several pin member 20, the unevenness | corrugation according to the cross-sectional shape of the pin member 20 is formed in the outer peripheral surface along with the circumferential direction, and the pin which comprises an outer peripheral surface External teeth are formed by the outer peripheral portion of the member 20. In short, the cylindrical portion 24 having external teeth on the outer peripheral surface is constituted by a plurality of pin members 20 arranged in the circumferential direction. The external teeth of the present embodiment have a substantially semi-cylindrical tooth surface and are arranged side by side in the circumferential direction, but the external teeth are not limited to a semi-cylindrical shape, depending on the shape of the pin member 20. There may be a polygonal column shape.

  Further, an elastic holding body 26 as a holding means is attached to the cylindrical portion 24. The elastic holding body 26 is formed of an elastic material such as rubber or elastomer, has a ring shape, and is externally fitted to the base end portion of the cylindrical portion 24. Further, the inner diameter dimension of the elastic holder 26 is slightly smaller than the outer diameter dimension of the neutral cylindrical portion 24 in which the pin member 20 is disposed so as to extend on the central axis of the support hole 22. Since the elastic holding body 26 is externally fitted to the portion 24, a force in the inner circumferential direction is elastically exerted on the cylindrical portion 24.

  As shown in FIGS. 2 to 4, a circular spline 14 and a wave generator 16 are assembled to the flexspline 12 having such a structure.

  The circular spline 14 is a hard member made of synthetic resin or metal, has a substantially annular shape, and has an inner tooth with a shape corresponding to the pin member 20 of the flexspline 12 on the inner peripheral surface. 28 is formed. The inner teeth 28 are formed two more than the pin members 20 constituting the outer teeth, and 52 inner teeth 28 are formed side by side in the circumferential direction. A plurality of screw holes 30 penetrating in the axial direction are formed at equal intervals on the outer peripheral portion of the circular spline 14. Further, the inner peripheral surface of the circular spline 14 is inclined with respect to the central axis, and the inner teeth 28 and the tooth grooves thereof are also inclined with respect to the central axis.

  The cylindrical portion 24 of the flex spline 12 is inserted into the inner periphery of the circular spline 14. Note that the circular spline 14 is disposed axially away from the support member 18 of the flexspline 12, and relative rotation with respect to the support member 18 is allowed without causing frictional resistance.

  The wave generator 16 has a stepped cylindrical shape whose outer diameter changes in the middle in the axial direction, and the outer diameter of the small diameter portion 31 is substantially the same as or slightly smaller than the inner diameter of the support member 18 of the flexspline 12. In addition, a plurality of screw holes 32 opened to the end face in the axial direction are distributed on the circumference.

  The large-diameter portion 33 of the wave generator 16 has a cylindrical surface whose inner peripheral surface is a cylindrical surface extending in the axial direction with a substantially constant circular cross section, and a tapered cylindrical surface 34 whose outer peripheral surface is inclined with respect to the central axis. Thus, the diameter increases as the distance from the small diameter portion 31 increases in the axial direction. The tapered cylindrical surface 34 is inclined in a direction corresponding to the inner peripheral surface of the circular spline 14, and the tapered cylindrical surface 34 and the inner peripheral surface of the circular spline 14 are at least long in a state where the tapered cylindrical surface 34 is arranged to be inserted / extracted later. The shaft portions face each other substantially in parallel.

  Further, the large-diameter portion 33 of the wave generator 16 has an outer peripheral surface that is a substantially elliptic cylindrical surface, and the outer diameter dimension in the minor axis direction is substantially the same or slightly smaller than the inner diameter dimension of the neutral cylindrical portion 24. On the other hand, the outer diameter dimension in the major axis direction is made larger than the inner diameter dimension of the neutral cylindrical portion 24.

  The wave generator 16 is inserted into the flex spline 12. That is, the wave generator 16 has a small-diameter portion 31 inserted into the inner periphery of the support member 18 of the flexspline 12 and a large-diameter portion 33 inserted into the inner periphery of the tubular portion 24 of the flexspline 12. 14 and the entire circumference are opposed to each other in the radial direction.

  After the flex spline 12, the circular spline 14 and the wave generator 16 are assembled in an extrapolated state, the front cover member 36 is attached to the circular spline 14 and the rear cover member 38 is attached to the wave generator 16. 12, the circular spline 14 and the wave generator 16 are positioned relative to each other in the axial direction.

  The front lid member 36 has a substantially annular plate shape, and a screw (not shown) that is inserted into the insertion hole 40 that is formed through the outer peripheral portion is screwed into the screw hole 30 of the circular spline 14. It is fixed to the circular spline 14. The inner peripheral portion of the front lid member 36 fixed to the circular spline 14 protrudes to the inner periphery from the circular spline 14, the axial end surface of the pin member 20 of the flexspline 12, and the large diameter of the wave generator 16. The portions 33 are overlapped in the axial direction with respect to the axial end surface.

  On the other hand, the rear lid member 38 has a substantially annular plate shape with a smaller diameter than the front lid member 36, and a screw (not shown) inserted into the insertion hole 42 penetrating in the thickness direction is a small diameter portion of the wave generator 16. It is fixed to the wave generator 16 by being screwed into the screw hole 32 of 31. The outer end of the rear lid member 38 fixed to the wave generator 16 is overlapped with the support member 18 of the flexspline 12 in the axial direction.

  As a result, the flex spline 12, the circular spline 14, and the wave generator 16 are positioned relative to each other in the axial direction in the mounted state of the front lid member 36 and the rear lid member 38, and constitute the wave gear device 10 in the present embodiment. Yes. In addition, since the protruding front end surface of the pin member 20 is covered with the front lid member 36 in a state where the flex spline 12 and the circular spline 14 are positioned in the axial direction, the pin member 20 is prevented from falling off from the support hole 22. Thus, the pin member 20 is supported by the support member 18.

  Further, the pin member 20 constituting the cylindrical portion 24 of the flex spline 12 is urged toward the inner periphery from the neutral position by the elastic holding body 26, so that the outer peripheral surface of the large-diameter portion 33 of the wave generator 16 is applied. It is elastically held in the pressed state and is arranged along the outer peripheral surface of the wave generator 16. In this embodiment, all the pin members 20 are held in contact with the outer peripheral surface of the wave generator 16, but the pin members 20 located on both sides in the long axis direction of the wave generator 16 are on the outer peripheral surface of the wave generator 16. As long as they are in contact, the pin members 20 located on both sides of the wave generator 16 in the short axis direction may be held away from the outer peripheral surface of the wave generator 16.

  Further, in the present embodiment, the pin member 20 constituting the external teeth is prevented from rolling by being pressed against the outer peripheral surface of the wave generator 16 by the elastic holding body 26, and the pin is operated when the wave gear device 10 is operated. The member 20 does not roll.

  The elastic holding body 26 is a component of the flex spline 12, but it is desirable that the elastic generator 26 be externally fitted to the cylindrical portion 24 after the wave generator 16 is inserted into the cylindrical portion 24. The spline 12 is completed while attached to the wave generator 16. When the elastic holding body 26 is attached to the cylindrical portion 24 before the wave generator 16 is inserted into the cylindrical portion 24, the pin member 20 is tilted inward by the elasticity of the elastic holding body 26 to form a cylindrical shape. This is because the opening of the portion 24 is reduced, making it difficult to insert the wave generator 16 into the cylindrical portion 24. In FIGS. 6 to 9, in order to show that the elastic holding body 26 is a component of the flexspline 12, the elastic holding body 26 is attached to the cylindrical portion 24. The tilting of the pin member 20 due to the urging force is shown in the illustration.

  The pin member 20 has a cylindrical portion 24 partially on the circumference by the wave generator 16 at a portion where the outer peripheral surface in the major axis direction of the wave generator 16 is pressed (upper and lower both side portions in FIG. 2). It is pushed to the outer periphery. In other words, the plurality of pin members 20 pressed against the outer circumferential surface of the wave generator 16 in the major axis direction are tilted from the neutral position so as to incline to the outer circumference (upward and downward in FIG. 2) as they go to the protruding tip. As a result, the cylindrical portion 24 is partially expanded to the outer periphery. In the present embodiment, the pin member 20 is supported by the support member 18 in a manner in which tilting in the radial direction is allowed, and is elastically held in the radial direction by the elastic holding body 26. 20 is tilted to the outer peripheral side against the elasticity of the elastic holding body 26 by the contact of the long axis portion of the wave generator 16.

  In this way, when the cylindrical portion 24 is partially expanded to the outer periphery by the wave generator 16, the plurality of pin members 20 constituting the expanded portion of the cylindrical portion 24 are arranged on the circular spline 14 side. And is engaged with the internal teeth 28 of the circular spline 14. In short, in the pin member 20 arranged over the entire circumference, a plurality of the wave generator 16 located at two positions in the longitudinal direction are meshed with the inner teeth 28, and the outer teeth of the cylindrical portion 24 and the circular splines 14 The internal teeth 28 are partially meshed on the circumference.

  Further, since the outer peripheral surface of the large-diameter portion 33 of the wave generator 16 has an elliptical cross-sectional shape, the cylindrical portion 24 of the flexspline 12 is formed in the short axis direction (left-right direction in FIG. 2) of the large-diameter portion 33. Is held along the outer peripheral surface of the wave generator 16 without being spread to the outer periphery by the wave generator 16. Thereby, in the short axis direction of the large-diameter portion 33 of the wave generator 16, the pin member 20 is positioned away from the inner teeth 28 of the circular spline 14 toward the inner circumference, and tooth engagement is avoided. .

  Accordingly, the pin member 20 constituting the external teeth of the flex spline 12 and the internal teeth 28 of the circular spline 14 are partially meshed with each other on the circumference. In this embodiment, the pin member 20 and the internal teeth 28 are The wave generator 16 is meshed on both sides in the long axis direction.

  In this embodiment, the pin member 20 constituting the cylindrical portion 24 is supported at one end in the axial direction by the support member 18, and the displacement amount to the outer peripheral side due to the tilting of the pin member 20 is the length of the pin member 20. A large ratio can be obtained. Therefore, even when the length of the pin member 20 is relatively short, the pin member 20 and the internal teeth 28 are held apart in the short axis direction of the wave generator 16 and meshed in the long axis direction. It is possible to reduce the size of the wave gear device 10 in the axial direction.

  The wave gear device 10 having such a structure is operated as follows, for example. That is, the circular spline 14 is fixed to a case or the like (not shown) and supported so as not to rotate, while an input shaft (not shown) is fixed to the wave generator 16 so that the input shaft can be rotated by an electric motor or the like. An output shaft (not shown) is fixed to the spline 12 so that the rotation of the flex spline 12 is output to the outside by the output shaft.

  Then, a rotational driving force is input to the wave generator 16 via the input shaft, and the wave generator 16 is rotated relative to the circular spline 14. As a result, the direction of the major axis of the large-diameter portion 33 of the wave generator 16 changes in the circumferential direction as the wave generator 16 rotates, so that the pin member 20 of the flex spline 12 that meshes with the inner teeth 28 of the circular spline 14. The position changes sequentially in the circumferential direction as the wave generator 16 rotates. Here, since the number of the pin members 20 of the flexspline 12 constituting the outer teeth and the number of the inner teeth 28 of the circular spline 14 are different from each other, the pin members 20 and the inner teeth 28 are sequentially bited on the circumference. In combination, when the wave generator 16 makes a round, the flex spline 12 rotates in the direction opposite to the rotation direction of the wave generator 16 according to the difference and the size of the number of pin members 20 and internal teeth 28. Thereby, it is possible to obtain an output decelerated at a ratio corresponding to the number of teeth 20 and 28 from the flex spline 12 with respect to the input to the wave generator 16. In the present embodiment, 50 pin members 20 as external teeth and 52 internal teeth 28 of the circular spline 14 are provided, so the reduction ratio is 50: 2.

  In the present embodiment, the pin member 20 is inclined with respect to the central axis of the cylindrical portion 24 at the portion where the pin member 20 of the flexspline 12 and the inner tooth 28 of the circular spline 14 mesh, but the inner tooth 28 of the circular spline 14. The tooth groove extends in an inclined manner with respect to the central axis of the circular spline 14 along the inclined pin member 20. Therefore, the pin member 20 and the internal teeth 28 are engaged with each other in a wide area in the axial direction, so that the torque (torque capacity) that can be transmitted can be set large. In addition, since the outer peripheral surface of the wave generator 16 that pushes the pin member 20 to the outer periphery is inclined with respect to the central axis along the tilted pin member 20, the pin member 20 meshes with the inner teeth 28 in a wide area. Thus, the target power transmission is stably realized.

  Furthermore, since the pin member 20 of the present embodiment is pressed against the outer peripheral surface of the wave generator 16 by the elastic holding body 26 and is prevented from rolling, power transmission due to friction at the time of rolling of the pin member 20 is performed. A decrease in efficiency is also avoided.

  In the wave gear device 10 having such a structure according to the present embodiment, the cylindrical portion 24 of the flexspline 12 is constituted by a plurality of pin members 20 arranged in the circumferential direction, and the pin member 20 constituting the external teeth is provided. By being tilted partially on the circumference of the cylindrical portion 24, it meshes with the internal teeth 28 of the circular spline 14. Thus, the cylindrical part 24 of the flexspline 12 is composed of a plurality of pin members 20 that can be tilted and displaced substantially independently on the circumference, so that the cylindrical part continuous in the circumferential direction. High-precision machining is not required as in the conventional flexspline with Therefore, the advanced processing of the cylindrical portion, which is required when manufacturing the conventional flexspline, becomes unnecessary in the flexspline 12 of the present invention, and the manufacturing is facilitated and the manufacturing cost is expected to be reduced. it can.

  In addition, since the holding means for holding the cylindrical portion 24 in contact with the outer peripheral surface of the wave generator 16 is provided as an elastic holding body 26 that is separate from the cylindrical portion 24, the conventional means is provided. Thus, it is not necessary to give the cylindrical portion 24 a holding function. Therefore, the pin member 20 constituting the cylindrical portion 24 employs a material that can realize the dimensional accuracy for realizing the meshing accuracy required for the gear teeth and the durability against scraping, and the like. By adopting the holding body 26 that can realize appropriate holding of the pin member 20 and durability against repeated elastic deformation, the wave gear device 10 having excellent performance can be easily obtained.

  In short, in a flexspline formed by cutting a conventional metal material, tooth shape (dimension) accuracy and strength, moderate elasticity, and durability against repeated input were realized by a single metal member. However, in the flex spline 12 according to the present invention, the same function is realized by being shared by the pin member 20 constituting the cylindrical portion 24 and the elastic holding body 26 that holds the pin member 20. Therefore, the flexspline 12 having performance equivalent to or better than that of the conventional flexspline can be easily realized by using the hard rod-shaped pin member 20 and the elastic holding body 26 of the ring-shaped elastic body, which are easy to manufacture. Is done.

  Further, the support member 18 that supports the plurality of pin members 20 side by side has a simple annular structure and can be easily manufactured. Moreover, the pin member 20 according to the present embodiment can be easily attached to the support member 18 by inserting one end portion in the axial direction into the support hole 22 of the support member 18, so that the assembling work is also simple. It is.

  Furthermore, in the present embodiment, the holding member that holds the pin member 20 in contact with the outer peripheral surface of the wave generator 16 and allows tilting to the outer periphery when pressed by the wave generator 16 is a cylindrical portion. The ring-shaped elastic holding body 26 is fitted on the outer periphery 24. Therefore, the elastic holding body 26 can be attached to the cylindrical portion 24 very easily, and the plurality of pin members 20 are elastically biased toward the inner periphery, thereby stabilizing the outer surface of the wave generator 16. Can be pressed.

  In the present embodiment, the flex spline 12, the circular spline 14, and the wave generator 16 are all made of synthetic resin, making it easy to manufacture each component and simplifying the weight reduction of the wave gear device 10. To be realized. In particular, flexsplines that have been difficult to be made into resins because high dimensional accuracy and strength are required in the past can be made of resin by adopting the structure according to the present invention, and further weight reduction is possible. Has been. Furthermore, for example, if the circular spline 14 and the pin member 20 of the flex spline 12 are formed of a resin material having a small surface friction coefficient, the power loss can be reduced by reducing the frictional resistance at the tooth meshing portion.

  The forming material of the flex spline 12, the circular spline 14, and the wave generator 16 is not particularly limited, and a metal, a synthetic resin, a rubber elastic body, a polymer elastomer or the like is used alone or in combination. Can be done. However, even if a metal material similar to that of the conventional flexspline is adopted, according to the present invention, each component can be easily manufactured because the tolerance of dimensional errors is large due to the difference in structure. it can. In addition, the flexspline 12, the circular spline 14, and the wave generator 16 are a plurality of parts formed of different materials, such as making the forming material of the support member 18 and the forming material of the pin member 20 different in the flexspline 12. It is also possible to form a combination.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the pin member is not limited to a cylindrical shape. Specifically, it may be a shape having a non-circular cross section such as a polygonal column shape as in the pin member 50 shown in FIG. Note that the pin member mounting structure (for example, the support hole 22) in the support member 18 and the shape of the internal teeth 28 of the circular spline 14 are appropriately changed in accordance with the shape of the pin member.

  In addition, the number of pin members 20 and the number of internal teeth 28, and the difference between these numbers are the number of lobes of the wave generator 16 (the number of portions that push the cylindrical portion 24 in the large diameter portion 33 outward), It can be changed as appropriate according to the required reduction ratio.

  Furthermore, when the pin member 20 having a circular cross section as in the above embodiment is employed, the pin member 20 may be supported by the support member 18 so as to be able to roll.

  Further, the support member that positions and supports the pin member 20 in the circumferential direction may be attached so as to support the intermediate portion in the axial direction of the pin member. It is not limited to what supports. Furthermore, the mounting structure of the pin member 20 and the support member 18 in which the axial end portion of the pin member 20 shown in the embodiment is inserted into the support hole 22 is merely an example, and for example, the pin member 20 is perpendicular to the axis. The structure etc. which equip the inner peripheral surface or the outer peripheral surface with a plurality of concave portions fitted together in FIG.

  Further, the specific structure of the elastic holding body is not limited to the ring shape that is externally fitted to the cylindrical portion 24 shown in the embodiment. That is, an elastic holding body may be disposed between the inner peripheral surface of the support hole 22 of the support member 18 and the outer peripheral surface of the pin member 20, for example, by covering the inner peripheral surface of the support hole 22 with a rubber layer. Can be done. Further, the elastic holder is not necessarily provided as an independent component. For example, the pin member 20 itself is formed of an elastic body so that the pin member 20 also serves as the elastic holder. It may be held by its own elasticity. Similarly, if the support member 18 is formed of an elastic body and the support member 18 also serves as an elastic holding body, the pin member 20 is held by the elasticity of the support member 18. In addition to the case where the pin member 20 itself is formed of an elastic body, the wave generator 16 moves to the outer peripheral side depending on the support mode by the support member or the elastic holding body and the pressing mode by the outer peripheral surface of the wave generator 16. Even when the pin member 20 is spread out, the entire pin member 20 may not be inclined with a clear inclination angle. However, it is understood that the pin member 20 tilts when at least the tip of the pin member 20 moves to the outer peripheral side from the initial position. For example, even when the entire pin member 20 moves to the outer peripheral side, it can be grasped as a tilting mode in which the inner end 28 of the circular spline 14 can be engaged with the movement of the tip end of the pin member 20 to the outer peripheral side.

  Furthermore, the holding means for holding the pin member 20 on the outer peripheral surface of the wave generator 16 is not limited to the elastic means of the member. For example, a magnetic attraction is provided between the outer peripheral surface of the wave generator 16 and the pin member 20. A force may be applied so that the pin member 20 is attracted and held on the outer peripheral surface of the wave generator 16.

  In the embodiment, the flex spline 12, the circular spline 14, and the wave generator 16 are all made of resin, but their forming materials are not particularly limited, and are made of metal such as iron or aluminum alloy, for example. It may be.

  The wave generator 16 has, for example, a structure in which an elliptical plate-like cam plate is disposed on the inner periphery of a ball bearing having a flexible inner ring and an outer ring, and the cam plate is fixed to the inner ring of the ball bearing. Can also be employed. By adopting such a structure with ball bearings, a reduction in power transmission efficiency due to friction between the wave generator 16 and the flexspline can be suppressed. The number of lobes of the wave generator 16 may be three or more, and generally the difference in the number of teeth between the external teeth 20 and the internal teeth 28 is set to an integral multiple of the number of lobes.

  In the above-described embodiment, the circular spline 14 is fixed to be non-rotatable and an output shaft is attached to the flexspline 12 so that the rotation of the flexspline 12 is taken out as an output. May be fixed to be non-rotatable, and an output shaft may be attached to the circular spline 14 so that the rotation of the circular spline 14 is taken out as an output. Further, by fixing the circular spline 14 so as not to rotate and attaching the input shaft to the flex spline 12 and attaching the output shaft to the wave generator 16, the wave gear device 10 can also function as a speed increaser.

10: Wave gear device, 12: Flex spline, 14: Circular spline, 16: Wave generator, 18: Support member, 20, 50: Pin member, 22: Support hole, 24: Cylindrical part, 26: Elastic holder, 28: Internal teeth

Claims (11)

It has a cylindrical portion inserted into an annular circular spline having a plurality of inner teeth arranged in the circumferential direction on the inner peripheral surface, and the outer peripheral surface of the cylindrical portion has a plurality of different numbers from the inner teeth. The outer teeth of the cylindrical portion are formed side by side in the circumferential direction, and the cylindrical portion is partially pushed outward on the circumference by a wave generator inserted in the cylindrical portion. In a flex spline for a wave gear device in which outer teeth are partially meshed with the inner teeth of the circular spline on the circumference,
While the cylindrical part provided with the external teeth is constituted by a plurality of pin members, the pin members are supported side by side in the circumferential direction by a support member,
Holding means for holding these pin members on the outer peripheral surface of the wave generator is provided,
The cylindrical portion is partially expanded on the periphery by the wave generator so that the pin member is tilted and meshed with the internal teeth of the circular spline.
In the other part on the circumference of the cylindrical part, the pin member is held by the holding means at a position away from the inner circumference without meshing with the inner teeth of the circular spline. Flex spline for wave gear device.   The holding means is an elastic holding body, and the pin member is elastically held on the outer peripheral surface of the wave generator by the elastic holding body, and the pin member is tilted by elastic deformation of the elastic holding body. The flex spline for a wave gear device according to claim 1, which is allowed.   The flexspline for a wave gear device according to claim 2, wherein the elastic holding body is annular, and the elastic holding body is externally fitted to the cylindrical portion constituted by a plurality of the pin members.   The flexspline for a wave gear device according to any one of claims 1 to 3, wherein one end portion of the pin member in the axial direction is supported by the support member.   A plurality of support holes are formed in the support member, one end of the pin member in the axial direction is inserted and supported in the support hole, and the hole cross-sectional shape of the support hole is directed toward the opening. The flexspline for a wave gear device according to claim 4, wherein the pin member is allowed to tilt and is allowed to tilt.   The holding means is an elastic holding body, the elastic holding body is interposed between the inner peripheral surface of the support hole and the outer peripheral surface of the pin member, and one end of the pin member in the axial direction is The flexspline for a wave gear device according to claim 5, which is elastically supported by the support member.   The flex spline for a wave gear device according to any one of claims 1 to 6, wherein the pin member is supported by the support member so as not to roll.   The flexspline for a wave gear device according to claim 7, wherein the pin member has a non-circular cross section.   The wave generator that is overlapped with the inner peripheral surface of the circular spline that is overlaid on the outer peripheral surface of the cylindrical portion, and that is overlapped with the inner peripheral surface of the cylindrical portion to partially push the cylindrical portion outward on the circumference The flexspline for a wave gear device according to any one of claims 1 to 8, wherein the outer peripheral surface of each of the first and second outer peripheral surfaces is inclined in directions corresponding to each other with respect to the central axis.   The flex spline for a wave gear device according to any one of claims 1 to 9, wherein at least one of the pin member and the support member is formed of a synthetic resin. A circular spline having an annular inner surface formed with inner teeth is formed, and a cylindrical portion of the flexspline is inserted into the inner periphery of the circular spline, and the outer periphery of the cylindrical portion of the flexspline A number of external teeth different from the internal teeth of the circular spline are formed on the surface, and a wave generator is inserted on the inner periphery of the flexspline, and the cylindrical portion of the flexspline is In the wave gear device in which the outer teeth of the portion that has been partially expanded to the outer periphery on the periphery by the wave generator and are expanded by the wave generator are meshed with the inner teeth of the circular spline,
A wave gear device using the flex spline according to any one of claims 1 to 10.