JP7449887B2 - friction transmission - Google Patents

Description

The present invention relates to a friction transmission device.

Patent Document 1 describes a continuously variable transmission device in which rolling elements are provided between an input side transmission member and an output side transmission member. This transmission device includes an input roller that rotates integrally with the input shaft, an output ring that rotates integrally with the output shaft, a speed change ring, and a plurality of planetary planets each having a friction surface in contact with the input roller, the output ring, and the speed change ring. It includes a roller and a movable holder that holds a plurality of planetary rollers so that they can rotate and revolve. The input roller, output ring, speed change ring, and planetary rollers constitute a traction transmission section.

Japanese Patent Application Publication No. 2014-031800

The continuously variable transmission described in Patent Document 1 includes a biasing spring that generates a thrust load and a member that receives the load from the biasing spring in order to apply pressurization to the friction surface of the traction transmission section. There is. It is important that the member receiving the load from the biasing spring be processed with high precision in order to appropriately transmit the spring load to the friction surface. Therefore, this member has had to be a member that requires high manufacturing costs.

The present invention was made in view of such problems, and one of the objects is to provide a friction transmission device that can reduce manufacturing costs.

In order to solve the above problems, a friction transmission device according to an aspect of the present invention includes a shaft, an input race arranged around the outer periphery of the shaft, and an input race arranged around the rotational axis of the input race and in contact with the input race. A friction transmission device comprising: a planetary rolling element that rotates; and an idling raceway ring that contacts the planetary rolling element; a spring that pressurizes the planetary rolling element; It has a bearing and a second bearing that supports the shaft. The spring contacts the raceway rings of the first bearing and the second bearing.

Note that arbitrary combinations of the above-mentioned components and mutual substitution of the components and expressions of the present invention between methods, systems, etc. are also effective as aspects of the present invention.

According to the present invention, it is possible to provide a friction transmission device that can reduce manufacturing costs.

FIG. 2 is a side sectional view showing a cross section of the friction transmission device according to the embodiment. FIG. 2 is an enlarged view showing the vicinity of a spring of the friction transmission device of FIG. 1; FIG. 2 is a diagram showing a spring of the friction transmission device of FIG. 1;

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on preferred embodiments with reference to the drawings. In the embodiments and modified examples, the same or equivalent components and members are given the same reference numerals, and redundant explanations will be omitted as appropriate. Further, the dimensions of members in each drawing are shown enlarged or reduced as appropriate to facilitate understanding. Further, in each drawing, some members that are not important for explaining the embodiments are omitted.

Also, although ordinal terms such as first, second, etc. are used to describe various components, these terms are used only to distinguish one component from another; The components are not limited by this.

[Embodiment]
The configuration of a friction transmission device 100 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a side sectional view showing a cross section of the friction transmission device 100. FIG. 2 is an enlarged view showing the periphery of a spring 50, which will be described later. The friction transmission device 100 of this embodiment transmits input power through contact between a plurality of friction transmission bodies and an output raceway. In the friction transmission device 100, the output raceway has a friction surface (also a raceway surface) of the friction transmission body, and the friction surface may not be a mere cylindrical surface but a surface inclined with respect to the central axis. . The friction transmission device 100 of this embodiment is a transmission device that changes the speed of rotation input from a drive source (not shown) and outputs it to an output raceway. In particular, the friction transmission device 100 is configured to cause the friction transmission body to rotate and revolve by rotating the input raceway, and output the generated rotational component to the output raceway.

The friction transmission device 100 includes a shaft 12, an input race 14, a plurality of planetary rolling elements 20, a support race 26, an idling race 28, an output race 30, a casing 40, and a bearing housing section. 44, an output flange 46, an output shaft 48, a spring 50, a main bearing 52, a first bearing 54, a second bearing 56, and a third bearing 58. Hereinafter, the direction along the central axis La of the shaft 12 will be referred to as the "axial direction", and the circumferential direction and radial direction of a circle centered on the central axis La will be referred to as the "circumferential direction" and the "radial direction", respectively. Further, for convenience, one side in the axial direction (the right side in the figure) will be referred to as the input side, and the other side (the left side in the figure) will be referred to as the counter-input side.

The input raceway 14 is arranged around the outer periphery of the shaft 12 . The plurality of planetary rolling elements 20 are arranged around the rotation axis La of the input raceway 14 . The plurality of planetary rolling elements 20 contact the input race 14, the support race 26, the idle race 28, and the output race 30, and together with these races constitute a friction transmission mechanism.

The output raceway ring 30 is arranged on the opposite input side of the planetary rolling element 20. The casing 40 surrounds the idler race 28 , the first bearing 54 , the second bearing 56 , the third bearing 58 and the spring 50 . The bearing accommodating portion 44 functions as a casing that accommodates the main bearing 52 and the output flange 46 mainly on the non-input side. The output flange 46 is fixed to the non-input side of the output raceway 30. The output shaft 48 projects from the end surface of the output flange 46 on the non-input side toward the non-input side. The spring 50 is bent in the axial direction to pressurize the planetary rolling element 20.

The shaft 12 is an input shaft to which the rotation of the drive source is input at the end on the input side, and rotates around the central axis La. The shaft 12 of this embodiment is a circular member extending in the axial direction. On the outer periphery of the shaft 12, from the non-input side to the input side, an input bearing ring 14, a bearing ring fitting part 122, a first bearing fitting part 123, a spring arrangement part 124, and a bearing arrangement part 125. , a circumferential recess 127, and a connecting portion 128 are provided in this order. The input bearing ring 14 extends radially in the shape of a flange near the end of the shaft 12 on the non-input side. In this embodiment, the input raceway 14 rotates integrally with the shaft 12. The input raceway 14 may be formed separately and fixed to the outer periphery of the shaft 12. An output shaft (not shown) of a drive source is connected to the connecting portion 128 .

The second bearing 56 supports the shaft 12. The second bearing 56 is arranged between the bearing arrangement portion 125 of the shaft 12 and the casing 40. Although there is no limitation on the configuration of the second bearing 56, the second bearing 56 of this embodiment is a deep groove ball bearing having a spherical rolling element 562, an outer ring 563, and an inner ring 564. The outer ring 563 is supported by the inner circumference of the casing 40, and the inner ring 564 fits into the bearing arrangement portion 125 of the shaft 12 and supports the shaft 12.

The idle bearing ring 28 is a hollow cylindrical member rotatably supported by the shaft 12 via the third bearing 58. The end face of the input side of the idle bearing ring 28 contacts the non-input side of the first bearing 54 and receives the biasing force of the spring 50 via the first bearing 54 . The biasing force of the spring 50 is a force directed toward the opposite input side in the axial direction, and pressurizes the idling raceway ring 28 toward the planetary rolling element 20 side.

The idle bearing ring 28 has a rolling surface 28h on the non-input side. The rolling surface 28h is a surface on which the planetary rolling element 20 rolls, and substantially makes point contact with the first contact surface 202 on the input side of the planetary rolling element 20. The rolling surface 28h is inclined with respect to the axial direction and the radial direction. The rolling surface 28h includes a tapered surface whose diameter decreases toward the non-input side. The rolling surface 28h may be a curved surface such as a convex surface or a concave surface, but in this example, it is a flat surface.

The third bearing 58 is a hollow cylindrical radial bearing disposed between the bearing ring fitting portion 122 of the shaft 12 and the idle bearing ring 28, and is a cylindrical roller bearing in this example. The third bearing 58 may be a sliding bearing such as an oil-impregnated metal bearing.

The first bearing 54 receives the load of the idle bearing ring 28 in the axial direction. The first bearing 54 fits on the outer periphery of the first bearing fitting part 123 of the shaft 12 and is arranged between the idler ring 28 and the second bearing 56 in the axial direction. The first bearing 54 is supported by the shaft 12. A spring 50 is disposed between the first bearing 54 and the second bearing 56. Although there is no limitation on the configuration of the first bearing 54, the first bearing 54 of this embodiment is a thrust bearing having a plurality of cylindrical rolling elements 542, a thrust plate 543, and a retainer 544. The cylindrical rolling elements 542 are cylindrical rollers that extend in the radial direction and are arranged at predetermined intervals in the circumferential direction. The thrust plate 543 is a hollow disk-shaped member arranged on the input side of the cylindrical rolling element 542. The non-input side of the cylindrical rolling element 542 is in direct contact with the input side end surface of the idle bearing ring 28 . In other words, the input side end face of the idle bearing ring 28 functions as a rolling surface of the cylindrical rolling element 542. The retainer 544 holds the cylindrical rolling element 542.

The planetary rolling elements 20 function as a friction transmission body that transmits rotation while performing planetary motion between the input raceway 14 , the support raceway 26 , the idling raceway 28 , and the output raceway 30 . The planetary rolling element 20 is a disc-shaped member, and a first contact surface 202 is provided on the outer peripheral side of the input side surface, and a second contact surface 204 is provided on the outer peripheral side of the non-input side surface. The first contact surface 202 and the second contact surface 204 are inclined with respect to the axial direction and the radial direction, and approach each other toward the outer circumferential side of the planetary rolling element 20.

A plurality of (for example, six) planetary rolling elements 20 are arranged at predetermined intervals in the circumferential direction. Although a retainer may be provided to hold the plurality of planetary rolling elements 20 at desired positions, this embodiment does not include a retainer. A structure without a retainer is advantageous in terms of manufacturing cost, device size, device mass, etc. Note that the number of planetary rolling elements 20 is not particularly limited, and may be less than or greater than 6, but is preferably 6 to 12.

In this embodiment, the support raceway 26 and the idling raceway 28 contact the first contact surface 202 of the planetary rolling element 20, and the input raceway 14 and the output raceway 30 contact the second contact surface 202 of the planetary rolling element 20. Contact surface 204. The input raceway 14 contacts the planetary rolling elements 20 on the radially inner side of the output raceway 30 , and the idler raceway 28 contacts the planetary rolling elements 20 on the radially inner side of the support raceway 26 .

The input raceway 14 contacts the planetary rolling element 20, and causes the planetary rolling element 20 to rotate and revolve as the input raceway 14 rotates. The input bearing ring 14 may be formed separately from the shaft 12, but in this example, it is formed integrally with the shaft 12. The input bearing ring 14 is a substantially disc-shaped member and has a rolling surface 14h on the input side. The rolling surface 14h is a surface on which the planetary rolling element 20 rolls, and is substantially in point contact with the planetary rolling element 20. The rolling surface 14h is inclined with respect to the axial direction and the radial direction. The rolling surface 14h includes a tapered surface whose diameter decreases toward the input side. The rolling surface 14h may be a curved surface such as a convex surface or a concave surface, but in this example, it is a flat surface. The rolling surface 14h substantially faces the rolling surface 28h of the idle raceway ring 28 with the planetary rolling element 20 in between.

The support raceway ring 26 and the idling raceway raceway 28 maintain the attitude and position of the planetary rolling element 20 within a certain range. The support raceway ring 26 is arranged on the input side of the planetary rolling element 20 and on the radially outer side of the idler raceway ring 28 . Idle raceway ring 28 is arranged on the input side of planetary rolling element 20 and radially inside support raceway 26 . The idling bearing ring 28 is arranged to face the input bearing ring 14 in the axial direction with the planetary rolling element 20 in between. The support raceway 26 is arranged to face the output raceway 30 in the axial direction with the planetary rolling elements 20 in between. The output raceway 30 is disposed on the opposite input side of the planetary rolling elements 20 and on the radially outer side of the input raceway 14 . The input raceway 14 is disposed on the opposite input side of the planetary rolling elements 20 and on the radially inner side of the output raceway 30 .

The support raceway 26 has a cylindrical portion 264 that surrounds the planetary rolling elements 20 and the output raceway 30 with a gap therebetween. The support raceway ring 26 has a rolling surface 26h facing toward the non-input side at a portion extending radially inward from the input side end of the cylindrical portion 264. The rolling surface 26h is a surface on which the planetary rolling element 20 rolls, and is substantially in point contact with the planetary rolling element 20. The rolling surface 26h is inclined with respect to the axial direction and the radial direction. The rolling surface 26h includes a tapered surface whose diameter decreases toward the input side. The rolling surface 26h may be a curved surface such as a convex surface or a concave surface, but in this example, it is a flat surface. The cylindrical part 264 of the support bearing ring 26 is arranged between the casing 40 and the bearing housing part 44, and is fixed to the casing 40 and the bearing housing part 44 with bolts B1.

The output raceway ring 30 contacts the planetary rolling element 20 and rotates about the central axis as the planetary rolling element 20 rotates. In this example, the rotation axis of the output raceway 30 coincides with the center axis La, so the output raceway 30 rotates around the center axis La. The output raceway 30 is fixed to the output flange 46 by bolts B2, and as the output raceway 30 rotates, the output flange 46 rotates.

The output raceway ring 30 has an annular body portion 302 surrounding the shaft 12 and the planetary rolling elements 20, and a hollow disk-shaped disk portion 304 extending radially inward from the non-input side of the body portion 302. The output raceway 30 has a rolling surface 30h on the input side of the main body 302. The rolling surface 30h is a surface on which the planetary rolling element 20 rolls, and is substantially in point contact with the planetary rolling element 20. The rolling surface 30h is inclined with respect to the axial direction and the radial direction. The rolling surface 30h includes a tapered surface whose diameter decreases toward the non-input side. The rolling surface 30h may be a curved surface such as a convex surface or a concave surface, but in this example, it is a flat surface. The rolling surface 30h substantially faces the rolling surface 26h of the support raceway 26 with the planetary rolling element 20 in between.

Hereinafter, when the rolling surface 30h of the output bearing ring 30, the rolling surface 14h of the input bearing ring 14, the rolling surface 26h of the support bearing ring 26, and the rolling surface 28h of the idle bearing ring 28 are collectively referred to, they will simply be referred to as "rolling surface 28h". It is sometimes referred to as "moving surface".

The axial position, radial position, and attitude of the planetary rolling element 20 are regulated by contacting the four rolling surfaces. The shape of the planetary rolling element 20 may be any shape as long as its attitude is determined by contacting the four rolling surfaces and can roll while contacting the four rolling surfaces. The planetary rolling element 20 in this example has an annular shape that is flat in the axial direction and has a convexly curved surface that contacts the four rolling surfaces.

The casing 40 includes a hollow cylindrical tubular portion 404 extending in the axial direction, a disk-shaped flange portion 402 extending radially outward from the non-input side of the tubular portion 404, and a radially inward extending from the input side of the tubular portion 404. It is a circular member having a hollow disk portion 406. The flange portion 402 faces the input side of the planetary rolling element 20 and surrounds the idling bearing ring 28 . Tubular portion 404 surrounds first bearing 54 , second bearing 56 , third bearing 58 and spring 50 . The disc portion 406 faces the input side of the second bearing 56 . The connecting portion 128 of the shaft 12 passes through the center hole 408 of the disc portion 406 and projects toward the input side.

A second bearing 56 fits into the tubular portion 404 . A set screw 41 extending in the radial direction is screwed into the tubular portion 404 . The tip of the set screw 41 is in contact with the outer ring 563 of the second bearing 56, and the second bearing 56 is fixed while the position of the second bearing 56 is adjusted. A plurality of setscrews 41 may be provided spaced apart in the circumferential direction.

The bearing housing portion 44 includes a hollow cylindrical bearing support portion 444 extending in the axial direction, a cylindrical portion 446 extending in the axial direction from the input side of the bearing support portion 444, and a cylindrical portion 446 extending radially inward from the non-input side of the bearing support portion 444. It is a circular member having a hollow extension portion 442 that extends. The bearing support portion 444 surrounds the main bearing 52 , and the extension portion 442 abuts the non-input side of the outer ring 523 of the main bearing 52 . In this example, the inner diameter of the cylindrical portion 446 is larger than the inner diameter of the bearing support portion 444.

The main bearing 52 is arranged between the bearing housing part 44 and the output flange 46, and rotatably supports the output flange 46 with respect to the bearing housing part 44. Although there is no limitation to the configuration of the main bearing 52, the main bearing 52 of this embodiment is a cross roller bearing having a plurality of cylindrical rolling elements 522, an outer ring 523, and an inner ring 524. The outer ring 523 fits into the inner periphery of the bearing support portion 444 , and the inner ring 524 fits into the outer periphery of the output flange 46 .

The output flange 46 is a disk-shaped member fixed to the opposite input side of the disk portion 304 of the output raceway 30 . The output flange 46 axially faces the end surface of the shaft 12 on the non-input side, and covers the non-input side of the friction transmission mechanism.

The output shaft 48 is a cylindrical member that protrudes from the non-input side of the output flange 46 and extends toward the non-input side. In this example, the output shaft 48 is integrally formed with the output flange 46. The output shaft 48 and the output flange 46 rotate integrally with the output raceway 30 and output the decelerated rotation taken out to the output raceway 30.

The spring 50 is a biasing member that pressurizes the idling bearing ring 28 in the axial direction toward the planetary rolling element 20 side. Although there is no limitation on the configuration of the spring 50, the spring 50 of this embodiment is a disc-shaped disc spring in which the inner circumferential side protrudes more toward the input side than the outer circumferential side. In this case, a large pressurization can be applied to the idle bearing ring 28 in a small space, and the transmission capacity of the friction transmission mechanism can be increased.

FIG. 3 is a diagram showing the spring 50 of the friction transmission device 100. 3(A) is a side view of the spring 50, and FIG. 3(B) is a rear view of the spring 50. The spring 50 is a hollow circular member having a through hole 506 through which the shaft 12 passes. As shown in FIG. 3(A), the spring 50 is provided with a first contact portion 502 that contacts the first bearing 54 on the radially outer non-input side, and a second bearing 56 on the radially inner input side. A second contact portion 504 that contacts the bearing ring is provided. In this example, the second contact portion 504 contacts the inner ring 564 of the second bearing 56 . In this case, the first bearing 54 and the inner ring 564 of the second bearing 56 rotate together, and the spring 50 comes into contact with the inner ring of the first bearing 54 and the second bearing 56 that rotate together with the shaft 12, so that the spring 50 is not worn out. Reduced. Further, the spring 50 applies a biasing force toward the input side to the inner ring 564, and pressurizes the space between the inner ring 564 and the outer ring 563.

Return to Figure 2. The position of the second bearing 56 is regulated by a retaining ring 60 that fits onto the shaft 12 . In this case, the pressurization can be adjusted on the shaft 12 side before connecting the casing 40 and the like. Further, the second bearing 56 can be positioned with a simple configuration. The retaining ring 60 fits into the circumferential recess 127 of the shaft 12 and contacts the inner ring 564 of the second bearing 56 with the shim 62 in between.

A shim 62 for pressurization adjustment is provided on the opposite side of the second bearing 56 from the spring 50. In this case, the pressurization of the spring 50 can be adjusted with a simple configuration. The shim 62 is inserted between the inner ring 564 of the second bearing 56 and the retaining ring 60. The set screw 41 is used to fix the second bearing 56. Pressure adjustment is performed by first inserting the shim 62 and then inserting the retaining ring 60. The preload can be adjusted depending on the thickness of the shim 62 to be inserted. By adjusting the pressurization, the transmission characteristics of the friction transmission mechanism can be ensured.

The first bearing 54 is a bearing that receives a load only in the axial direction. In this case, the structure can be made more compact than a bearing that receives a radial load.

Since the shaft 12 rotates at high speed, the first bearing 54 and the second bearing 56 generate heat, raising the temperature of surrounding members. If the first bearing 54, second bearing 56, and spring 50 become excessively hot, the pressurization changes, which affects the transmission characteristics of the friction transmission mechanism. Furthermore, when the thermal conductivity of the shaft 12 is high, heat is transmitted to the planetary rolling elements 20 via the shaft 12, causing thermal expansion of the planetary rolling elements 20, which affects the transmission characteristics of the friction transmission mechanism. Therefore, this embodiment includes a casing 40 that surrounds the spring 50, and the casing 40 is made of a material having higher thermal conductivity than the shaft 12. In this case, the heat generated by the first bearing 54 and the second bearing 56 is dissipated into the atmosphere by the casing 40, which has high thermal conductivity, so that it is possible to suppress the temperature rise of the surrounding members. The amount of heat transferred to the planetary rolling elements 20 via the shaft 12 can be reduced. As a result, the influence on the transmission characteristics of the friction transmission mechanism can be reduced.

In the shaft 12, the diameter of the spring arrangement part 124 where the spring 50 is arranged is larger than the diameter of the bearing arrangement part 125 where the second bearing 56 is arranged. In this case, the second contact portion 504 of the spring 50 can be brought into contact with an area avoiding the inner chamfered portion of the inner ring 564, which is unstable in shape. As a result, the second contact portion 504 can appropriately transmit the biasing force and stabilize pressurization.

The operation of the friction transmission device 100 configured as above will be explained. When rotational power is transmitted from the drive source to the shaft 12, the input bearing ring 14 rotates around the central axis La. When the input bearing ring 14 rotates, the planetary rolling elements 20 revolve around the revolution axis while rotating around the rotation axis. In this example, the revolution axis of the planetary rolling elements 20 coincides with the central axis La. The rotation of the planetary rolling elements 20 is transmitted to the output raceway 30, and the output raceway 30 rotates. The output shaft 48 and the output flange 46 rotate integrally with the output raceway 30 and output the decelerated rotation taken out to the output raceway 30.

When the idle bearing ring 28 is freely rotating and the support bearing ring 26 is non-rotating and stationary, the output bearing ring 30 has a predetermined speed change determined by the position of each contact point with respect to the rotation of the input bearing ring 14. Rotate by ratio. The speed ratio of the friction transmission device 100 can be adjusted by changing the inclination angle of the rotation axis of the planetary rolling element 20 with respect to the central axis La. When the inclination angle of the planetary rolling elements 20 is constant, the gear ratio is kept constant.

The characteristics of the friction transmission device 100 configured as above will be explained. The friction transmission device 100 includes a shaft 12 , an input race 14 disposed around the outer periphery of the shaft 12 , a planetary rolling element 20 disposed around the rotation axis La of the input race 14 and in contact with the input race 14 , A friction transmission device comprising an idling raceway ring 28 that contacts the planetary rolling element 20, a spring 50 that pressurizes the planetary rolling element 20, and a first bearing 54 that receives the load in the axial direction of the idling raceway ring. and a second bearing 56 that supports the shaft 12. The spring 50 abuts against the races of the first bearing 54 and the second bearing 56 .

According to this configuration, the members receiving the biasing force from the spring 50 are the bearing rings of the first bearing 54 and the second bearing 56, and since these are originally machined with high precision, the pressurized force generated by the spring 50 is can be appropriately transmitted to the friction surface of the friction transmission mechanism. This is advantageous in terms of manufacturing costs because the number of man-hours required to rework the member receiving the biasing force from the spring 50 with high precision can be reduced.

Examples of embodiments of the present invention have been described above in detail. The embodiments described above are merely specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of constituent elements may be made without departing from the idea of the invention defined in the claims. It is possible. In the above-mentioned embodiment, contents that allow such design changes are explained with the notations such as "in the embodiment" and "in the embodiment," but the design changes are not made in the content without such notation. This does not mean that changes are not allowed. Further, the hatching added to the cross section of the drawing does not limit the material of the hatched object.

A modified example will be explained below. In the drawings and description of the modified example, the same reference numerals are given to the same or equivalent components and members as in the embodiment. Explanation that overlaps with the embodiment will be omitted as appropriate, and configurations that are different from the embodiment will be mainly explained.

In the description of the embodiment, an example is shown in which the spring 50 is a disc spring, but the spring 50 may be a biasing member of a different configuration from the disc spring, such as a coil spring.

In the description of the embodiment, an example was shown in which the spring 50 directly contacts the raceway of the second bearing 56, but the spring 50 may also come into contact with the raceway of the second bearing 56 via a spacer. Furthermore, although an example has been shown in which the spring 50 directly contacts the first bearing 54, the spring 50 may contact the first bearing 54 via a spacer.

In the description of the embodiment, an example was shown in which the output raceway ring 30 contacts the non-input side of the planetary rolling element 20 and the support raceway ring 26 contacts the input side of the planetary rolling element 20, but the invention is not limited to this. For example, a configuration may be adopted in which the output raceway ring 30 contacts the input side of the planetary rolling element 20 and the support raceway ring 26 contacts the non-input side of the planetary rolling element 20.

In the description of the embodiment, an example is shown in which the first bearing 54 is a thrust bearing having a cylindrical rolling element 542, but the present invention is not limited thereto. For example, the rolling elements of the first bearing 54 may have a shape other than a cylindrical shape, such as a spherical shape.

Each of the above-mentioned modifications has the same functions and effects as the embodiment.

Any combination of components and variations of the embodiments described above are also useful as embodiments of the invention. A new embodiment resulting from a combination has the effects of each of the combined embodiments and modified examples.

100 friction transmission device, 12 shaft, 14 input bearing ring, 20 planetary rolling element, 26 support bearing ring, 28 idling bearing ring, 30 output bearing ring, 40 casing, 50 spring, 54 first bearing, 56 second bearing, 58 third bearing, 60 retaining ring, 62 shim, 124 spring arrangement section, 125 bearing arrangement section, 564 inner ring.

Claims (8)

a shaft, an input raceway arranged around the outer periphery of the shaft, a planetary rolling element arranged around the rotational axis of the input raceway and in contact with the input raceway, and an idling orbit in contact with the planetary rolling element. A friction transmission device comprising a ring,
a spring that pressurizes the planetary rolling element;
a first bearing that receives a load in the axial direction of the idle bearing ring;
a second bearing that supports the shaft;
The spring is a friction transmission device in which the spring contacts the raceway of the first bearing and the second bearing. the first bearing is supported by the shaft,
The friction transmission device according to claim 1, wherein the spring contacts an inner ring of the second bearing. The friction transmission device according to claim 1 or 2, wherein the second bearing is positionally regulated by a retaining ring that fits on the shaft. The friction transmission device according to claim 3, wherein a shim for pressurization adjustment is provided on a side of the second bearing opposite to the spring. The friction transmission device according to any one of claims 1 to 4, wherein the first bearing is a bearing that receives a load only in an axial direction. The friction transmission device according to any one of claims 1 to 5, further comprising a casing surrounding the spring, the casing being made of a material having higher thermal conductivity than the shaft. 7. The friction transmission device according to claim 1, wherein, in the shaft, a diameter of a spring arrangement part where the spring is arranged is larger than a diameter of a bearing arrangement part where the second bearing is arranged. The friction transmission device according to any one of claims 1 to 7, wherein the spring is a disc spring.

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