KR102503263B1 - Flexible engagement gear device - Google Patents

Abstract

[PROBLEMS] To provide a bending meshing type gear device capable of reducing the weight and taking measures against heat generation of gears.
Bending meshing type gear having a vibrating body 12, an external gear 14 bent by the vibrating body 12, and internal gears 18-A and 18-B meshing with the external gear 14 As a device, the internal gears 18-A and 18-B are made of resin, the external gear 14 is made of a high thermal conductivity material with higher thermal conductivity than resin, and the vibrating bearings 16-A and 16- B) has a rolling element 16a that rolls the inner circumferential surface of the outer gear 14. When the internal gears 18-A, 18-B and the external gear 14 generate heat, heat transfer from the engaged position to other locations through the external gear 14 made of high heat conduction material is promoted. Heat dissipation in other places can be promoted. Therefore, by using resin for the internal gears 18-A and 18-B, it is possible to reduce the weight and take measures against heat generation of the gears.

Description

Bending engagement gear device {Flexible engagement gear device}

This application claims priority based on Japanese Patent Application No. 2017-204323 filed on October 23, 2017. The entire content of that application is incorporated herein by reference.

The present invention relates to a bending meshing type gear device.

BACKGROUND OF THE INVENTION [0002] As a small-sized gear device from which a high reduction ratio can be obtained, a bending meshing type gear device is known. In recent years, the use of gear devices has been diversified, and there is a case where weight reduction is requested in this type of bending meshing type gear device. As a response to this request, Patent Literature 1 discloses a bending meshing type gear device using resin for internal gears and external gears.

Patent Document 1: Japanese Unexamined Patent Publication No. 2013-170611

However, when resin is used for gears, there is a concern that the life of the gears may decrease due to the influence of thermal deterioration when heat is generated at the meshing portion of the gears. A bending meshing type gear device in which this countermeasure is taken has not yet been proposed, and the proposal is desired.

One aspect of the present invention is made in view of such a situation, and one of the objects is to provide a bending meshing type gear device capable of taking measures against heat generation of gears while achieving weight reduction.

One aspect of the present invention relates to a bending meshing type gear device, which includes an excitation body, an external gear bent by the vibration body, and an internal gear meshing with the external gear. As a gear device, the internal gear is made of resin, the external gear is made of a high thermal conductivity material having a higher thermal conductivity than the resin, and the vibrating body bearing has a rolling element for rolling the inner circumferential surface of the external gear.

ADVANTAGE OF THE INVENTION According to this invention, the countermeasure against heat generation of a gear can be taken while achieving weight reduction.

1 is a side sectional view showing a gear device of a first embodiment.
FIG. 2 is an enlarged view of a portion of FIG. 1 .
In Fig. 3, Fig. 3 (a) is a front cross-sectional view schematically showing the engagement state of the external gear and the internal gear, and Fig. 3 (b) shows part of the range A in Fig. 3 (a). is an enlarged
Fig. 4 is a side cross-sectional view showing a part of a gear device of a second embodiment.

Hereinafter, in the embodiments and modified examples, the same reference numerals are assigned to the same components, and overlapping descriptions are omitted. In addition, in each drawing, for convenience of explanation, some of the components are appropriately omitted or the dimensions of the components are appropriately enlarged or reduced.

(First Embodiment)

1 is a side sectional view showing a gear unit 10 according to a first embodiment. The gear device 10 rotates the external gear by changing the engagement position for the internal gear in the circumferential direction while bending the external gear that engages with the internal gear, and outputs its rotation component. The gear device of the present embodiment is a so-called tubular bending meshing type gear device that decelerates and outputs the rotation of the vibrating body 12 using an internal gear 18-A for reduction and an internal gear 18-B for output. am.

The gear device 10 mainly includes a vibrating body 12, an external gear 14, a vibrating body bearing 16-A, 16-B, an internal gear 18-A, 18-B, A support member 20 and bearing housings 22-A and 22-B are provided. Hereinafter, the direction along the rotation center line La of the vibrating body 12 is simply referred to as "axial direction X", and with respect to the circumferential direction and radial direction centered on the rotation center line La, simply "circumferential direction" "," is sometimes referred to as the "radial direction".

The vibrating body 12 is a tubular member having rigidity. A drive shaft (not shown) of a driving device such as a motor is connected to the vibrating body 12 using a key or the like. The vibrating body 12 can be rotated with its own shaft center as the rotation center by the drive shaft. However, the driving device is arranged on one side (right side in the drawing) of the axial direction X rather than the vibrating body 12 . Hereinafter, one side in the axial direction X is referred to as an input side, and the other side (left side in the drawing) is referred to as a counter-input side.

The vibrating body 12 has a hollow part 12a formed on the inner side in the radial direction of the vibrating body bearings 16-A and 16-B. The hollow part 12a penetrates the central part in the radial direction of the vibrating body 12 in the axial direction X. An insertion member (not shown) such as wiring is inserted into the hollow portion 12a. By forming the hollow part 12a in the vibrating body 12, the weight of the gear device 10 can be achieved.

The vibration body 12 has an intermediate shaft portion 12b, an input side shaft portion 12c located on the input side from the intermediate shaft portion 12b, and a half-input side shaft portion 12d located on the input side from the intermediate shaft portion 12b. These intermediate shaft portions 12b, input-side shaft portions 12c, and half-input-side shaft portions 12d are provided outside the hollow portion 12a in the radial direction. The outer peripheral shape of the intermediate shaft part 12b in the cross section orthogonal to the axial direction X forms an ellipse. The input-side shaft portion 12c and the counter-input-side shaft portion 12d have a circular outer circumferential shape in a cross section orthogonal to the axial direction X. The "ellipse" in this specification is not limited to a geometrically strict ellipse, but also includes an approximate ellipse.

The outer gear 14 is disposed on the outer circumferential side of the intermediate shaft portion 12b of the vibrating body 12. The outer gear 14 is a tubular member having flexibility. The outer gear 14 has a tubular base 14a, a first outer tooth portion 14b and a second outer tooth portion 14c formed integrally with the base portion 14a on the outer circumferential side of the base portion 14a. ) has The 1st external tooth part 14b is arrange|positioned on the input side, and meshes with the internal gear 18-A for speed reduction mentioned later. The 2nd external tooth part 14c is arrange|positioned on the half input side, and meshes with the output internal gear 18-B mentioned later. In the first outer tooth portion 14b and the second outer tooth portion 14c, both sides in the long axis direction of the intermediate shaft portion 12b of the vibrating body 12 mesh with the internal gear 18.

The outer gear 14 follows the rotation of the vibrating body 12, and is bent into an elliptical shape through the vibrating body bearing 16 by the intermediate shaft portion 12b of the vibrating body 12. At this time, the external gear 14 is bent to fit the shape of the intermediate shaft portion 12b of the vibrating body 12 while changing the engagement position with the internal gears 18-A and 18-B in the circumferential direction.

The vibrating body bearings 16-A and 16-B are disposed between the intermediate shaft portion 12b of the vibrating body 12 and the external gear 14. In the vibrating body bearings 16-A and 16-B, the first vibrating body bearing 16-A disposed between the first external tooth portion 14b of the external gear 14 and the vibrating body 12, A second vibrating body bearing 16-B disposed between the second external tooth portion 14c of the external gear 14 and the vibrating body 12 is included. The vibrating body 12 rotatably supports the external gear 14 via the vibrating body bearings 16-A and 16-B. The plurality of vibrating body bearings 16-A and 16-B are arranged on both sides of the plurality of vibrating body bearings 16-A and 16-B in the axial direction X to the ring-shaped displacement regulating members 28. By touching, the displacement in the axial direction X is regulated.

Hereinafter, with regard to other components having commonalities, "first and second" are appended to both names and "-A, -B" are added to the end of the code to distinguish them, these are omitted when generic. For example, the 1st vibrating body bearing 16-A and the 2nd vibrating body bearing 16-B are described as "vibration body bearing 16" when generically named.

The vibrating body bearing 16 has a plurality of rolling elements 16a and a retainer 16b. The retainer 16b rotatably supports the plurality of rolling elements 16a while supporting the relative positions of the plurality of rolling elements 16a.

The rolling element 16a of this embodiment is a roller. The rolling element 16a of this embodiment is a cylindrical roller whose outer peripheral surface is provided along the axial direction X. The rolling element 16a of this embodiment rotates around the rotational axis along the axial direction X.

The rolling element 16a of this embodiment rolls the inner peripheral surface of the outer gear 14. The inner circumferential surface of the outer gear 14 serves as the outer ring of the vibrating body bearing 16. The vibrating body bearing 16 has a structure that does not have an outer ring capable of bending and deformation through which the rolling element 16a rolls.

The rolling element 16a of this embodiment rolls the outer circumferential surface of the intermediate shaft portion 12b of the oscillating element 12, and the outer circumferential surface of the oscillating element 12 is the inner rolling surface 30 on which the rolling element 16a rolls. function as The outer circumferential surface of the vibrating body 12 serves as the inner ring of the vibrating body bearings 16-A and 16-B. The vibrating body bearing 16 has a structure that does not have an inner ring on which the rolling elements 16a roll.

The internal gears 18-A and 18-B are annular members having such rigidity that they do not deform following the rotation of the vibrating body 12. The internal gears 18-A and 18-B are disposed on the outer circumferential side of the first external tooth portion 14b and the second external tooth portion 14c of the external gear 14. In the internal gears 18-A and 18-B of this embodiment, the internal gear 18-A (first internal gear) for speed reduction disposed on the input side and the internal gear 18-B for output disposed on the half-input side ) (second internal gear) is included.

The internal gear 18-A for speed reduction has a first internal tooth portion 18a to which the first external tooth portion 14b of the external gear 14 engages. The internal dimension of the first internal tooth portion 18a is greater than the external dimension of the first external tooth portion 14b by 2i (i is a natural number greater than or equal to 1). As a result, when the vibrating body 12 rotates, the rotation of the vibrating body 12 is decelerated at a reduction ratio according to the size difference between the first internal tooth portion 18a and the first external tooth portion 14b, so that the external tooth gear 14 rotate

The output internal gear 18-B has a second internal tooth portion 18c to which the second external tooth portion 14c of the external gear 14 engages. The inner dimension of the second inner tooth portion 18c is the same as the outer dimension of the second outer tooth portion 14c. Thereby, when the vibrating body 12 rotates, the rotation of the same magnitude as the rotation component of the external gear 14 is output to the internal gear 18-B for output.

The supporting member 20 is disposed radially outside the output internal gear 18-B, and rotatably supports the output internal gear 18-B via the main bearing 24. The support member 20 of this embodiment is integrated with the internal gear 18-A for speed reduction by using interference fit, intermediate fit, or the like. Although the supporting member 20 and the internal gear 18-A for speed reduction of this embodiment are separate bodies, they may constitute part of a single member.

The bearing housings 22 are arranged at intervals in the axial direction X. The bearing housing 22 includes an input-side bearing housing 22-A disposed on the input side and an input-reduction bearing housing 22-B disposed on the input-reduction side. The input side bearing housing 22-A is integrated with the internal gear for speed reduction 18-A using a bolt B1 or the like. The half input side bearing housing 22-B is integrated with the output internal gear 18-B using a bolt B3 or the like.

Between the input-side bearing housing 22-A and the input-side shaft portion 12c of the vibration body 12, or between the input-side bearing housing 22-B and the input-side shaft portion 12d of the vibration body 12, bearings (26) is placed. The pair of bearing housings 22-A and 22-B rotatably support the vibrating body 12 via bearings 26 on both sides.

The operation of the above gear unit 10 will be described. When the driving shaft of the driving device rotates, the vibrating body 12 rotates together with the driving shaft. When the vibrating body 12 rotates, the external gear 14 is continuously bent to match the shape of the intermediate shaft portion 12b of the vibrating body 12 while changing the engagement position with the internal gear 18 in the circumferential direction Transformed. Thereby, the 1st external tooth 14b corresponds to the size difference with the 1st internal tooth 18a of the internal gear 18-A for reduction|deceleration every time the vibration body 12 rotates once. It rotates (rotates) relative to the internal gear 18-A. At this time, the rotation of the oscillating body 12 is decelerated at a reduction ratio according to the difference in dimension with the first internal tooth portion 18a, and the outer gear 14 rotates. The second internal tooth portion 18c of the output internal gear 18-B has the same dimensions as the second external tooth portion 14c. Therefore, the internal gear 18-B for output is synchronized with the same rotational component as the external gear 14 while the relative engagement position with the second external tooth portion 14c does not change before and after the vibrating body 12 rotates once. to rotate The rotation of this output internal gear 18-B is transmitted from the output internal gear 18-B to the driven device. As a result, the rotation of the oscillating body 12 is decelerated and output from the output internal gear 18-B to the driven device.

Here, in the gear device 10 of the first embodiment, one feature is that the internal gear 18 is made of resin and the outer gear 14 is made of a high heat conductive material. The resin constituting the internal gear 18 (hereinafter, referred to as gear resin) is, for example, a general-purpose engineered plastic such as polyacetal or polyamide. The "resin" of the present invention also includes composite materials of resin and other materials. This composite material is, for example, carbon fiber reinforced resin or glass fiber reinforced resin. In this embodiment, both the internal gear 18-A for speed reduction and the internal gear 18-B for output are comprised by resin for gears. However, only one of the internal gear 18-A for reduction|deceleration and the internal gear 18-B for output may be comprised by resin for gears.

The outer tooth gear 14, that is, each of the base 14a, the first outer tooth portion 14b, and the second outer tooth portion 14c is constituted by a high thermal conductivity material. This high thermal conductivity material refers to a material having a higher thermal conductivity [W/(m·K)] than gear resin, that is, a material in which heat is more easily transferred than gear resin. In this embodiment, although metals such as iron and aluminum are used as the high thermal conductive material, other resins having higher thermal conductivity than gear resins may be used.

As a result, when heat is generated at the meshing location of the internal gear 18 and the external gear 14, heat transfer from the engaged area to other locations via the external gear 14 made of high thermal conductive material is promoted, and heat transfer is promoted at other locations. Heat dissipation is promoted. Here, other locations include members other than the external gear 14 (for example, the vibrating body bearing 16) other than the engaging position of the external gear 14 other than the position that becomes a part of the external gear 14. do. Therefore, the temperature of the internal gear 18 and the external gear 14 due to heat generation at the meshing location of the internal gear 18 and the external gear 14 can be suppressed. As a result, it is possible to prevent a decrease in the life of the internal gear 18 and the external gear 14 due to the influence of thermal deterioration, and good durability of the internal gear 18 and the external gear 14 can be obtained. For this reason, by using the gear resin for the internal gear 18, it is possible to achieve a countermeasure against heat generation of the gear while achieving weight reduction.

The high thermal conductive material preferably has a higher thermal conductivity than that of the resin for gears from the viewpoint of transferring heat generated at the meshing location of the gear to other locations. From this point of view, the thermal conductivity of the high thermal conductive material is preferably set to be 10.0 times or more of the thermal conductivity of the resin for gears, for example.

In the bending meshing type gear device 10, the internal gear 18, which is usually disposed on the outside in the radial direction of the external gear 14, has a larger volume than the external gear 14. In this embodiment, since this large-volume internal gear 18 is constituted by resin for gears, weight reduction can be achieved more effectively than when the external gear 14 of small volume is constituted by resin for gears. there is.

[0003] In seeking to improve the transmission efficiency of a bending meshing type gear device, reduction of the volume of the bending deformation portion is effective in order to reduce energy loss at the bending deformation portion. Here, the vibrating body bearing 16 has a rolling element 16a that rolls on the inner circumferential surface of the outer gear 14, and has a structure that does not have an outer ring capable of bending and deforming through which the rolling element 16a rolls. Therefore, as long as there is no outer ring that is bent together with the external gear 14, energy loss due to bending of the outer ring can be avoided, and high transmission efficiency of the gear device 10 can be achieved.

In addition, after using a sphere as the rolling element 16a, when the outer ring of the vibrating element bearing 16 is omitted, the contact area in the axial direction X between the inner peripheral surface of the outer gear 14 and the rolling element 16a gets smaller Accordingly, the axial distribution of the load transmitted from the rolling element 16a to the external gear 14 becomes non-uniform, and the tooth root of the load transmitted from the external gear 14 to the meshing location with the internal gear 18 ) direction (axial direction X) becomes non-uniform. In this respect, when a roller is used as the rolling element 16a, even if the outer ring of the vibrating element bearing 16 is omitted, the contact area in the axial direction X between the inner peripheral surface of the outer gear 14 and the rolling element 16a gets bigger Thereby, by equalizing the axial distribution of the load transmitted from the rolling element 16a to the external gear 14, the tooth root direction of the load transmitted from the external gear 14 to the meshing location with the internal gear 18 (axial The distribution in the direction X) can be made uniform, and their contact state can be stabilized.

In addition, as the high thermal conductive material of the present embodiment, a material having an elastic constant [Pa] larger than that of the resin for gears is used. The elastic constant of the high thermal conductive material is set to be 10 times or more of the elastic constant of the gear resin, for example. This is realized, for example, by a combination of the above-mentioned general-purpose engineered plastic and metal.

In this way, the fact that the elastic constant of the high thermal conductivity material is greater than that of the gear resin means that the load to be applied to elastically deform the high thermal conductive material is greater than that of the gear resin, and the energy loss due to elastic deformation is greater than that of the gear resin. means that Therefore, when such a high thermal conductive material having an elastic constant is used for the outer gear 14, compared to the case of using a high thermal conductive material having an elastic constant equal to or smaller than the elastic constant of the gear resin, the gear device 10 transfer efficiency tends to decrease. Even under a structure in which the transmission efficiency of the gear unit 10 tends to decrease in this way, as described above, by eliminating the outer ring of the vibrator bearing 16, high transmission efficiency of the gear unit 10 can be achieved. There is an advantage.

Other features of the gear unit 10 will be described. FIG. 2 is an enlarged view of a portion of FIG. 1 . As described above, the rolling element 16a of the vibrating body bearing 16 rolls the outer peripheral surface of the intermediate shaft portion 12b of the vibrating body 12. This intermediate shaft portion 12b constitutes a rolling element rolling portion 12e in which the rolling element 16a rolls on the outer circumferential surface.

The thickness Ta of the outer gear 14 in the radial direction is set to be smaller than the thickness Tb of the rolling element rolling element 12e in the radial direction. The thickness (Ta) of the outer gear 14 and the thickness (Tb) of the rolling element rolling element 12e refer to the thickness at the thinnest point in the range over their entire circumference. Specifically, the thickness Ta of the outer gear 14 refers to the dimension in the radial direction from the tooth bottom 14d of the outer gear 14 to the inner peripheral surface 14e of the outer gear 14. . The thickness Ta of this outer gear 14 is measured under the condition that the outer gear 14 is separated from the vibrating body 12 and made into a perfect circle. In FIG. 2, the thickness Ta under the state attached to the vibrating body 12 is shown for explanatory convenience. Explain this advantage.

Figure 3 (a) is a front sectional view schematically showing the engagement state of the external gear 14 and the internal gear 18, Figure 3 (b) is a part of the range A of Figure 3 (a) is an enlarged view of When the external gear 14 is bent into an elliptical shape, the internal gear 18 normally engages both sides of the outer gear 14 in the long axis direction, and the other than the opposite side portions 14f in the long axis direction. become unreachable. At this time, the portion between the contact points of the outer gear 14 in contact with the plurality of rolling elements 16a (hereinafter referred to as the portion 14h between the contact points) is the restoring force (Fa) according to the bending deformation of the outer gear 14 ), it is intended to be deformed to be closer to the inner side in the diametric direction.

Here, when the thickness Ta of the external gear 14 is greater than the thickness Tb of the vibrating body 12, compared to the case where the condition is not satisfied, the portion between the contact points of the external gear 14 (14h) ) becomes difficult to deform so that it approaches the inside in the radial direction. In the example of Fig. 3(b), the portion 14h between the contact points of the outer gear 14 is less likely to be deformed to the point of the solid line, and it is easier to be located at the point of the double-dashed line. As a result, despite the fact that the portion 14h between the contact points should not touch the internal gear 18 in the vicinity of the both sides 14f in the long axis direction of the external gear 14, the internal gear 18 is unintentional. It becomes easier for contact situations to occur.

(A) If this point, the thickness Ta of the external gear 14 is made smaller than the thickness Tb of the vibrating body 12, compared to the case where the condition is not satisfied, the contact point of the external gear 14 It is easy to deform the liver portion 14h so as to approach the inside in the radial direction by the restoring force Fa according to the bending deformation. As a result, compared to the case where the thickness Ta of the external gear 14 does not satisfy the condition smaller than the thickness Tb of the vibrating body 12, the vicinity of the long axial direction both side portions 14f of the external gear 14 It is easy to avoid a situation where the portion 14h between the contact points touches the internal gear 18 unintentionally.

(B) In addition, when a sphere is used for the rolling element 16a, in the cross section along the axial direction X, the inner raceway 30 on which the rolling element 16a rolls can be made concave, so that the rolling element ( The contact area between 16a) and the inner raceway 30 can be increased. On the other hand, when a roller is used for the rolling element 16a, as shown in Fig. 1, in the cross section along the axial direction X, the rolling element 16a and the inner raceway 30 form a straight line. As a result, the contact area between the rolling element 16a and the inner raceway 30 is reduced compared to the case where a sphere is used for the rolling element 16a and the inner raceway 30 is concave, The surface pressure between the rolling element 16a and the inner raceway 30 increases, and the strength required of the member (vibrator 12) having the inner raceway 30 increases. Here, in this embodiment, since the thickness Tb of the vibrating body 12 is larger than the thickness Ta of the outer gear 14, compared to the case where the condition is not met, the vibrating body 12 It becomes easier to secure the required strength.

However, in this embodiment, from the viewpoint of achieving weight reduction, the support member 20 and the bearing housing 22 are made of resin such as resin for gears. In addition, from the viewpoint of securing strength against abrasion due to rolling of the rolling elements, the vibrating body bearing 16, the main bearing 24, and the bearing 26 are made of metal. From the same point of view, the vibrating body 12 having the inner raceway 30 on which the rolling elements 16a of the vibrating body bearing 16 roll is also made of metal. Here, when a bearing has a rolling element, an outer ring, and an inner ring, it is assumed that all of them are made of metal, but a part may be made of metal and the rest may be made of resin such as resin for gears.

(Second Embodiment)

Fig. 4 is a side cross-sectional view showing a part of the gear unit 10 according to the second embodiment. The gear device 10 of this embodiment differs from the first embodiment in the point of the vibrating body bearing 16. The vibrator bearing 16 has an inner ring 16c in addition to a plurality of rolling elements 16a and a retainer 16b. The inner ring 16c is a separate body from the plurality of rolling elements 16a and the vibrating element 12. The inner ring 16c is disposed between the plurality of rolling elements 16a and the intermediate shaft portion 12b of the vibrator 12. The inner ring 16c has an elliptical outer circumferential shape in a cross section orthogonal to the axial direction X. The inner ring 16c is provided rotatably integrally with the intermediate shaft portion 12b of the vibrating body 12 . In this embodiment, the inner ring 16c of a single number is shared by the 1st oscillator body bearing 16-A and the 2nd oscillator body bearing 16-B.

Unlike the first embodiment, the plurality of rolling elements 16a roll not on the outer circumferential surface of the intermediate shaft portion 12b of the oscillator 12 but on the outer circumferential surface of the inner ring 16c. The inner rolling surface 30 on which the rolling element 16a rolls is provided on the outer circumferential surface of the inner ring 16c. At this time, the thickness Ta of the outer gear 14 in the radial direction is set to be smaller than the thickness Tc of the inner ring 16c in the radial direction. The definition of the thickness Ta of the outer gear 14 here is as described above. In addition, as described above, the thickness Tc of the inner ring 16c refers to the thickness at the thinnest point in the range over the entire circumference.

Thereby, the same effect as the above-mentioned (A) is obtained. That is, if the thickness Ta of the outer gear 14 is made smaller than the thickness Tc of the inner ring 16c, compared to the case where the condition is not satisfied, the portion 14h between the contact points of the outer gear 14 (See Fig. 3) is easily deformed so as to approach the inside in the radial direction by the restoring force Fa according to the bending deformation. As a result, compared to the case where the condition that the thickness Ta of the outer gear 14 is smaller than the thickness Tc of the inner ring 16c is not met, in the vicinity of both sides 14f in the long axial direction of the outer gear 14 It becomes easy to avoid the situation where the part 14h between contact points touches the internal gear 18.

Moreover, the same effect as the above-mentioned (B) is acquired. That is, when a roller is used for the rolling element 16a, compared to the case where the inner raceway 30 is concave by using a sphere for the rolling element 16a, the rolling element 16a and the inner raceway 30 The surface pressure between them increases, and the strength required of the member (inner ring 16c) having the inner raceway 30 increases. Here, since the thickness Tc of the inner ring 16c is greater than the thickness Ta of the outer gear 14, it is easier to secure the required strength of the inner ring 16c than in the case where the condition is not met. .

Moreover, the vibrating body 12 of 2nd Embodiment is comprised by resin, specifically resin for gears. The inner ring 16c is made of metal. This metal is, for example, an iron-based material such as steel. Explain this advantage.

When the vibrating body 12 is made of resin, compared to the case where the vibrating body 12 is made of metal, weight reduction can be easily achieved, and the moment of inertia can be reduced through the weight reduction. Therefore, there is an advantage that the torque to be applied by the driving device can be reduced when accelerating or decelerating the oscillating body 12 rotating at a higher speed than other rotating elements of the gear device 10.

In the above, examples of embodiments of the present invention have been described in detail. The embodiments described above merely show specific examples in implementing the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as change, addition, and deletion of components are possible within a range that does not deviate from the spirit of the invention defined in the claims. In the above-described embodiment, descriptions such as "of the embodiment" and "in the embodiment" are attached to the contents in which such a design change is possible, but the design change is not permitted for the contents without such notation. no. In addition, the hatching pasted on the cross section of a drawing does not limit the material of the subject to which hatching is pasted.

As for the components of the gear device 10, as long as the internal gear 18 is made of resin and the outer gear 14 is made of a high thermal conductive material, the materials of the other components are not particularly limited. For example, as other components, there are the vibrating body 12, the vibrating body bearing 16, the bearing housing 22, the main bearing 24, the bearing 26, and the like. Regardless of the material of the external gear 14 and the internal gear 18, any of resin and high thermal conductivity material may be used for these.

The type of the flexural meshing type gear device is not particularly limited. For example, in addition to a tubular bending-meshing type gear device, a hat-type or cup-type bending-meshing type gear device may be used.

Although the example in which the rolling element 16a of the vibrating body bearing 16 is a cylindrical roller was demonstrated, another roller, such as a conical roller, may be sufficient as it, and a spherical shape may be sufficient as it.

Although the example of the high thermal conductive material having a larger elastic constant than that of the gear resin has been described, the elastic constant may be the same as or smaller than that of the gear resin.

The thickness Ta of the outer gear 14 of the first embodiment may be equal to or larger than the thickness Tb of the rolling element rolling portion 12e of the vibrator 12. In addition, the thickness Ta of the external gear 14 of the second embodiment may be equal to or larger than the thickness Tc of the inner ring 16c of the vibrator bearing 16.

10... gear unit
12... vibration body
12a... hollow part
12e... rolling element
14... shout gear
16-A, 16-B... vibrator bearing
16a... rolling element
16c... inner wheel
18-A, 18-B... kick gear

Claims (5)

An exciter body in which an outer circumferential shape of a cross section orthogonal to the axial direction is an ellipse;
An external gear that is bent and deformed by the vibrating body;
An oscillating body bearing disposed between the oscillating body and the outer gear;
As a bending meshing type gear device having an internal gear engaged with the external gear,
The internal gear is made of resin,
The outer gear is made of a high thermal conductivity material having higher thermal conductivity than the resin,
The vibrating body bearing is a bending meshing type gear device having a rolling element for rolling the inner circumferential surface of the outer gear. According to claim 1,
As the internal gear, it has a first internal gear and a second internal gear,
It has a main bearing for supporting the first internal gear and the second internal gear to be relatively rotatable,
The main bearing is a bending meshing type gear device made of metal. According to claim 1,
The oscillating body and the oscillating body bearing are constituted by metal. with the engine body,
An external gear that is bent and deformed by the vibrating body;
An oscillating body bearing disposed between the oscillating body and the outer gear;
As a bending meshing type gear device having an internal gear engaged with the external gear,
The internal gear is made of resin,
The outer gear is made of a high thermal conductivity material having higher thermal conductivity than the resin,
The vibrating body bearing has a rolling element for rolling the inner circumferential surface of the outer gear,
The vibrating body bearing has an inner ring separate from the vibrating body,
The thickness in the radial direction of the outer gear is smaller than the thickness in the radial direction of the inner ring. According to claim 4,
The vibrating body is made of resin,
The inner ring is a bending meshing type gear device made of metal.

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