JP2014040885A - Friction roller-type change gear - Google Patents

Abstract

To achieve a structure capable of reducing friction loss in a portion where rolling surfaces of inclined surfaces having a generatrix shape inclined with respect to the center of rotation are brought into contact with each other because it is necessary to improve the surface pressure with a pressing device.
Loading cam devices (15b, 15b) as the pressing devices are provided on the annular roller (13b) side. The distance from the rotation center of the annular roller 13b to the traction portion related to the inclined bus bar shape can be increased, and the difference in the peripheral speed at both ends of each traction portion can be reduced. As a result, the friction loss in each of these traction portions can be suppressed to a low level, and the above problem can be solved.
[Selection] Figure 1

Description

  The present invention relates to an improvement in a friction roller type transmission that transmits torque from an electric motor to driving wheels in a state where it is incorporated in a driving system of an electric vehicle, for example.

  In response to the recent trend of reducing fossil fuel consumption, research on electric vehicles has progressed and some have been implemented. Unlike an internal combustion engine (engine) that moves by directly burning fossil fuel, an electric motor that is a power source of an electric vehicle is preferable for an automobile in terms of output shaft torque and rotational speed characteristics (generally at startup) Therefore, it is not always necessary to provide a transmission such as a general automobile using an internal combustion engine as a drive source. However, even in the case of an electric vehicle, acceleration performance and high speed performance can be improved by providing a transmission. Specifically, by providing a transmission, the relationship between the traveling speed and acceleration of the vehicle can be made smooth, similar to a car equipped with a gasoline engine. This point will be described with reference to FIG.

  For example, when a power transmission device having a large reduction ratio is provided between an output shaft of an electric motor that is a drive source of an electric vehicle and an input portion of a differential gear connected to the drive wheel, the acceleration (G) of the electric vehicle And the traveling speed (km / h) are such that the left half of the solid line a in FIG. 4 and the chain line b are continuous. In other words, acceleration performance at low speed is excellent, but high-speed running is not possible. On the other hand, when a power transmission device with a small reduction ratio is provided in the intermediate portion, the relationship is such that the chain line c in FIG. 4 and the right half of the solid line a are continuous. That is, high-speed travel is possible, but acceleration performance at low speed is impaired. On the other hand, if a transmission is provided between the output shaft and the input unit and the reduction ratio of the transmission is changed according to the vehicle speed, the left half part and the right half part of the solid line a are made continuous. The following characteristics can be obtained. This characteristic is almost the same as that of a gasoline engine vehicle having the same level of output as indicated by the broken line d in FIG. 4, and it can be seen that the acceleration performance and the high speed performance can be equivalent to those of the gasoline engine vehicle.

  FIG. 5 shows an electric vehicle drive device that has been considered in view of such circumstances (Japanese Patent Application No. 2011-250531). The drive device for an electric vehicle according to the prior invention includes an electric motor 1 for driving a vehicle, a friction roller type speed reducer 2, a transmission 3, and a rotation transmission device 4. The input shaft 5 of the friction roller type reduction gear 2 and the output shaft 6 of the electric motor 1 for driving the vehicle are arranged concentrically with each other so that torque can be transmitted. An output shaft 19 (see FIG. 6 to be described later) of the friction roller type speed reducer 2 is disposed concentrically with the drive side rotating shaft 7 of the transmission 3 so as to be able to transmit torque.

The transmission 3 is provided with a pair of gear transmission mechanisms 9a and 9b having different reduction ratios between the driving side rotating shaft 7 and the driven side rotating shaft 8. Then, by switching between the pair of clutch mechanisms 10a and 10b, only one of the gear transmission mechanisms 9a (9b) is allowed to transmit power so that the drive side rotary shaft 7 and the driven side rotary shaft 8 can be transmitted. The reduction ratio between and can be converted into two steps of high and low.
Further, the rotation transmission device 4 is a general gear transmission mechanism in which a plurality of gears are combined. The rotation transmission device 4 transmits the rotation of the driven side rotation shaft 8 to the input portion of the differential gear 11 and a pair of left and right drive wheels. Is driven to rotate.

  For example, the friction roller type speed reducer 2 described in Patent Document 1 can be used. FIG. 6 shows the friction roller transmission 2 described in Patent Document 1. The friction roller type speed reducer 2 includes an input shaft 5, an output shaft 19, a sun roller 12, an annular roller 13, a plurality of planetary rollers 14 and 14, and a loading cam device 15. Of these, the sun roller 12 is concentrically arranged with a pair of sun roller elements 16a and 16b divided in the axial direction around the input shaft 5 with a gap interposed between the tip surfaces thereof. In addition, one of the sun roller elements 16a is arranged so as to be rotatable relative to the input shaft 5. The planetary rollers 14, 14 are rotatably supported around the planetary shafts 17, 17, and the outer peripheral surfaces thereof are the outer peripheral surface of the sun roller 12 and the inner peripheral surface of the annular roller 13. Rolling contact. The base end portions of the planetary shafts 17 and 17 are coupled and fixed to the base end portion of the output shaft 19 via a carrier 18.

  Further, the loading cam device 15 is provided between one sun roller element 16a and the input shaft 5, and the one sun roller element 16a is replaced with the other sun roller as the input shaft 5 rotates. The sun roller 12 composed of both the sun roller elements 16a and 16b is rotationally driven while being pressed toward the element 16b. For this purpose, a support ring 21 is locked to a middle portion of the input shaft 5 by a retaining ring 20, and the support ring 21 and the one sun roller element 16 a are sequentially arranged from the support ring 21 side. In addition, a disc spring 22, a cam plate 23, and a plurality of balls 24, 24, each of which is a rolling element, are provided. Then, the driven cam surfaces 25 and 25 and the driving cam surface 26 are respectively provided at a plurality of circumferential positions on the base end surface of the one sun roller element 16a and the one side surface of the cam plate 23, which face each other. , 26 are provided. Each of the cam surfaces 25 and 26 has a shape in which the depth in the axial direction is deepest in the central portion in the circumferential direction, and gradually becomes shallower toward both ends.

  In such a loading cam device 15, when the input shaft 5 is stopped, the balls 24, 24 are deepest on the cam surfaces 25, 26 as shown in FIG. Located in the part. In this state, the one sun roller element 16a is pressed toward the other sun roller element 16b by the elasticity of the disc spring 22. On the other hand, when the input shaft 5 rotates, the balls 24 and 24 move to shallow portions of the cam surfaces 25 and 26 as shown in FIG. And the space | interval of said one sun roller element 16a and the said cam board 23 is expanded, and said one sun roller element 16a is pressed toward the said other sun roller element 16b. As a result, the one sun roller element 16a is generated by the elasticity of the disc spring 22 and the balls 24 and 24 riding on the cam surfaces 25 and 26 toward the other sun roller element 16b. It is driven to rotate while being pressed by the larger force of the thrust to be applied.

  During operation of the friction roller type speed reducer 2 as described above, the outer circumferential surface of each of the planetary rollers 14, 14, the outer circumferential surface of the sun roller 12, and the annular shape are generated by the axial thrust generated by the loading cam device 15. The surface pressure of the rolling contact portion with the inner peripheral surface of the roller 13 increases. This surface pressure increases according to the magnitude of torque to be transmitted between the input shaft 5 and the output shaft 19. When the input shaft 5 is rotated in this state, the rotation is transmitted from the sun roller 12 to the planetary rollers 14, 14, and the planetary rollers 14, 14 are rotating around the sun roller 12. Revolve. Therefore, the revolving motion of each of the planetary rollers 14 and 14 is taken out by the output shaft 19 through the carrier 18.

If the friction roller type transmission 2 is arranged between the vehicle driving electric motor 1 and the transmission 3 as in the electric vehicle driving device shown in FIG. 5 described above, for efficient use of electric energy, Even if a small and high rotation type (for example, the maximum rotation speed is about 30,000 min ⁻¹ ) is used as the vehicle driving electric motor 1, vibration and noise during operation can be suppressed. That is, since the friction roller type speed reducer 2 is used as the first stage speed reducer, it is possible to suppress the occurrence of vibrations at the high speed rotating portion. The rotational speeds of the transmission 3 and the rotation transmission device 4, each of which is a gear transmission mechanism, are approximately the same as the driving speed of a transmission portion of a vehicle equipped with a general gasoline engine (up to several thousand min ⁻¹ Therefore, no unpleasant vibration or noise is generated in any part.

  In the friction roller transmission 2 shown in FIG. 6 described above, the annular roller 13 is fixed, and the intermediate rollers are used as the planetary rollers 14, 14. A structure is adopted in which the movement is taken out as a decelerated output via the carrier 18. On the other hand, there is a structure in which the intermediate roller can only rotate and the annular roller is rotated to transmit power. For example, although not disclosed, the Japanese Patent Application No. 2011-250531 discloses a friction roller type transmission 2a having a structure as shown in FIG. Although the present invention can be implemented even with the structure shown in FIG. 6 described above, it is preferable to implement the structure in which the annular roller is rotated to transmit power from the viewpoint of securing the surface pressure of each rolling contact portion. The structure shown in FIG. 9 will be briefly described.

  In the friction roller type speed reducer 2a shown in FIG. 9, the sun roller 12a is rotationally driven by the input shaft 5a, and the rotation of the sun roller 12a is transmitted to the annular roller 13a through a plurality of intermediate rollers 27 and 27. The rotation of the annular roller 13a is taken out from the output shaft 19a. Each of the intermediate rollers 27 and 27 rotates around the rotation shafts 28 and 28 provided at the center thereof, but does not revolve around the sun roller 12a. The sun roller 12a is formed by concentrically combining a pair of sun roller elements 16c and 16c having the same shape, and the loading cam device 15a is provided at a position sandwiching both the sun roller elements 16c and 16c from both sides in the axial direction. , 15a, and the two sun roller elements 16c, 16c are driven to rotate in the same direction while being pressed toward each other as the input shaft 5a rotates. Each component described above is housed in a stepped cylindrical housing 29.

  Further, the annular roller 13a is disposed concentrically with the sun roller 12a in the peripheral portion of the sun roller 12a at the axially intermediate portion of the housing 29. The inner peripheral surface of the annular roller 13a is a cylindrical surface whose inner diameter does not change in the axial direction, and the annular roller 13a and the base end portion of the output shaft 19a are connected by a connecting portion 30 having an L-shaped cross section.

  Further, the intermediate rollers 27 and 27 can freely rotate (rotate) around the rotation shafts 28 and 28 in an annular space between the inner peripheral surface of the annular roller 13a and the sun roller 12a. In addition, the annular roller 13a and the sun roller 12a are installed so as to be slightly displaceable in the radial direction. Further, the outer peripheral surfaces of the intermediate rollers 27 and 27 have an axially intermediate portion as a simple cylindrical surface, and both axial portions are inclined at the same angle in the same direction as the outer peripheral surfaces of the solar roller elements 16c and 16c. In this case, the inclined surface is convex. Accordingly, the peripheral surfaces of the rollers 12a, 13a, and 27 are in line contact with each other, and are the rolling contact portions of the peripheral surfaces of the rollers 12a, 13a, and 27, and transmit the torque. Can be secured.

  When the input shaft 5a is rotationally driven by an electric motor during the operation of the friction roller type speed reducer 2a according to the present invention configured as described above, both the sun roller elements 16c and 16c are moved to the both loading cam devices 15a, By the action of 15a, it is rotated in the same direction as the input shaft 5a at the same speed while being pressed toward each other. Then, the rotation of the sun roller 12a constituted by the both sun roller elements 16c and 16c is transmitted to the annular roller 13a through the intermediate rollers 27 and 27 and is taken out from the output shaft 19a.

  Regardless of the conventional structure shown in FIG. 6 or the structure according to the prior invention shown in FIG. 9, the surface pressure of each traction portion, which is a rolling contact portion between the peripheral surfaces of each roller, is secured. The loading cam devices 15 and 15a are provided on the sun rollers 12 and 12a side. In order to configure the loading cam devices 12 and 12a, the outer peripheral surface of the sun rollers 12 and 12a and the outer peripheral surface of the planetary rollers 14 and 14 or the intermediate rollers 27 and 27 are partially conical convex surfaces, respectively. Rolling contact between the inclined surfaces. For this reason, the friction loss regarding the outer peripheral surface of the sun rollers 12 and 12a and the outer peripheral surface of the planetary rollers 14 and 14 or the intermediate rollers 27 and 27 increases. The reason why this friction loss occurs is that the outer peripheral surfaces of these rollers 12, 12a, 14, and 27 are in line contact or close to line contact, whereas the rotation centers of these rollers 12, 12a, 14, and 27 are This is because the shaft and the generatrix of each outer peripheral surface are not parallel.

  And the said friction loss becomes so large that the difference of the peripheral speed is large between the both ends of each rolling contact part (traction part) of the outer peripheral surfaces of each said roller 12, 12a, 14, 27. In the case of the structure shown in FIGS. 6 and 9, since the distance (rotation radius) from the rotation center of the sun roller 12a to the traction parts is short, the sun is between the ends of the traction parts. A difference in angular velocity is increased with respect to the outer peripheral surface of the roller 12a, and a difference in peripheral speed is increased between both ends of these tractions. As a result, the friction loss in each of these traction portions increases, which is disadvantageous in terms of ensuring the transmission efficiency of the friction roller transmissions 2 and 2a.

JP 2004-116670 A

  In view of the above-described circumstances, the present invention can reduce friction loss at a portion where the inclined surfaces having the generatrix shape inclined with respect to the center of rotation are brought into rolling contact with each other because it is necessary to improve the surface pressure by the pressing device. It was invented to realize the structure.

The friction roller transmission of the present invention includes an input shaft and an output shaft, a sun roller, an annular roller, a plurality of intermediate rollers, and a surface pressure applying device.
Each of these intermediate rollers is installed in an annular space between the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller so that it can rotate at least. In contact with the outer peripheral surface of the annular roller and the inner peripheral surface of the annular roller.
The surface pressure applying device is for ensuring the surface pressure of the rolling contact portion between the peripheral surfaces of these rollers.
The input shaft and the output shaft can rotate relative to each other, and are arranged concentrically with the sun roller and the annular roller. The input shaft and the output shaft are coupled to two different elements to two types of elements selected from the supporting members that rotate together.

In particular, in the friction roller transmission of the present invention, the surface pressure applying device is provided on the annular roller side, and the intermediate rollers are pressed inward in the radial direction of the annular roller, The surface pressure of each rolling contact portion is increased.
And the friction roller type transmission of this invention is equipped with all the requirements of following (A)-(E).
(A) The annular roller is paired with an inner peripheral surface of a holding cylinder provided concentrically with the first rotating shaft at an end of the first rotating shaft that is one of the input shaft and the output shaft. The annular roller element is configured so as to be rotatable with the holding cylinder and capable of moving toward and away from each other.
(B) A pressing means is provided between the holding cylinder and at least one of the annular roller elements to press the annular roller elements toward each other.
(C) The inner peripheral surfaces of the annular roller elements are partially conical concave surfaces that are inclined in a direction in which the inner diameter increases toward the distal end surface, which is a surface of the annular roller elements facing each other.
(D) The outer peripheral surface of each of the intermediate rollers is a cylindrical surface in which the outer diameter of the intermediate portion in the axial direction does not change with respect to the axial direction, and the outer diameter increases toward the both end surfaces in the axial direction of the respective intermediate rollers. It is a partial conical convex surface that is inclined in the direction of decreasing.
(E) Among the sun rollers, at least a portion of the outer peripheral surface of each of the intermediate rollers where the intermediate portion in the axial direction may be in rolling contact is a cylindrical surface whose outer diameter does not change in the axial direction.

When implementing the friction roller type transmission of the present invention as described above, for example, as in the invention described in claim 2, the pressing means is disposed at a position sandwiching the annular roller elements from both sides in the axial direction. In addition, a pair of loading cam devices are provided.
Each of these loading cam devices is composed of an anchor plate, a plurality of cam surfaces, and a plurality of rolling elements.
The anchor plate is supported on the inner peripheral surface of the holding cylinder so as to be able to rotate in synchronization with the holding cylinder.
Further, each of the cam surfaces is formed at a plurality of locations on one side in the axial direction of the anchor plate and the base end surface of the annular roller element facing each other, and the cam surface is related to the axial direction toward the circumferential end. It is inclined in the direction in which the depth dimension decreases.
The rolling elements are sandwiched between the cam surfaces.
And, one anchor plate of the pair of anchor plates constituting the both loading cam devices is supported on the inner peripheral surface of the holding cylinder in a state in which axial displacement in the direction of retreating from the other anchor plate is prevented. To do.
Further, a spring that elastically presses the other anchor plate toward the one anchor plate is provided between the other anchor plate and the holding cylinder.

Alternatively, as in the invention described in claim 3, the pressing means is a loading cam device and a spring arranged at positions sandwiching the two annular roller elements from both axial sides.
Among them, the loading cam device is composed of an anchor plate, a plurality of cam surfaces, and a plurality of rolling elements, and the anchor plate can be rotated on the inner peripheral surface of the holding cylinder in synchronization with the holding cylinder. And it supports in the state which prevented the displacement of the direction away from one annular roller element of the said both annular roller elements.
Further, each of the cam surfaces is formed at a plurality of locations on one side in the axial direction of the anchor plate and the base end surface of the one annular roller element facing each other. It is inclined in the direction in which the depth dimension with respect to the direction becomes smaller.
The rolling elements are sandwiched between the cam surfaces.
Furthermore, the spring is provided between the base end face of the other annular roller element of the annular roller elements and the holding cylinder. The other annular roller element is elastically pressed toward the one annular roller element.

Alternatively, as in the invention described in claim 4, the pressing means is a spring.
Further, one annular roller element of both the annular roller elements is supported inside the holding cylinder portion in a state in which displacement in a direction away from the other annular roller element is prevented.
The spring is provided between a base end surface of the other annular roller element of the annular roller elements and the holding cylinder, and the other annular roller element is elastically directed toward the one annular roller element. Press.

According to the friction roller transmission of the present invention configured as described above, it is necessary to improve the surface pressure by the pressing device, and the friction at the portion where the inclined surfaces having the generatrix shape inclined with respect to the rotation center are brought into rolling contact with each other. Loss can be reduced.
That is, in the case of the structure of the present invention, since the pressing device is provided on the annular roller side, the distance (rotation radius) from the rotation center of the annular roller to each traction portion can be increased. For this reason, even when the inclination angle of the inclined surface is the same as that of the above-described conventional structure or the structure of the previous invention, the difference in peripheral speed between the both ends of each of the traction portions can be kept small. As a result, the friction loss in each of these traction portions can be reduced, and the transmission efficiency of the friction roller transmission can be easily ensured.

BRIEF DESCRIPTION OF THE DRAWINGS The half part schematic sectional drawing of the friction roller type transmission which shows the 1st example of embodiment of this invention. The half part schematic sectional drawing of the friction roller type transmission which shows the 2nd example. The half part schematic sectional drawing of the friction roller type transmission which shows the 3rd example. The diagram for demonstrating the effect by incorporating a transmission into the drive device for electric vehicles. The perspective view of the drive device for electric vehicles which concerns on a prior invention. Sectional drawing which shows an example of the friction roller type transmission conventionally known. The expanded AA sectional view of FIG. The expanded BB sectional drawing of FIG. Sectional drawing of the friction roller type transmission which concerns on a prior invention.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention corresponding to claims 1 and 2. The friction roller type transmission 2b of this example includes an outer peripheral surface of a sun roller 12b integrated with an input shaft, and an annular roller 13b concentrically connected to the output shaft 19b at a base end portion of the output shaft 19b. A plurality of intermediate rollers 27a are arranged in an annular space between the inner peripheral surface of the annular roller 13b and the outer peripheral surface of the sun roller 12b. The intermediate roller 27a supports a support frame (not shown) so as to be able to rotate, but supports a slight displacement in the radial and axial directions of the sun roller 12b and the annular roller 13b in a state in which revolving is prevented. Yes. The rotation of the sun roller 12b is transmitted to the annular roller 13b via the intermediate rollers 27a, and the rotation of the annular roller 13b can be taken out from the output shaft 19b.

The annular roller 13 b includes a holding cylinder 31 and a pair of annular roller elements 32 and 32. A pair of anchor plates 33, 33, a plurality of balls 24, 24, each of which is a rolling element, and a spring 34 are arranged on the inner diameter side of the holding cylinder 31 at a position sandwiching the annular roller 13 b from both axial sides. Are assembled.
Of these, the holding cylinder 31 is provided concentrically with the output shaft 19b at the base end portion of the output shaft 19b, and has a female spline portion on the inner peripheral surface thereof. Then, the outer peripheral edge portions of the two anchor plates 33, 33 are spline-engaged with the female spline portion so that both the anchor plates 33, 33 rotate in synchronization with the output shaft 19b.

  The annular roller elements 32 and 32 have an outer diameter smaller than the inner diameter (tooth tip diameter) of the female spline portion, and are arranged between the anchor plates 33 and 33 on the inner diameter side of the holding cylinder 31. The part is provided with a mutual movement. The inner circumferential surfaces of the annular roller elements 32, 32 are partially conical concave surfaces that are inclined in the direction in which the inner diameter increases toward the distal end surface side, which is the mutually opposing surfaces of the annular roller elements 32, 32. is there.

  In addition, driven cam surfaces 25a and 25a are formed at a plurality of circumferentially equidistant positions on one axial surface of the two anchor plates 33 and 33 facing each other. Drive-side cam surfaces 26a and 26a are respectively formed at a plurality of circumferentially equidistant positions on the base end surfaces of the annular roller elements 32 and 32, which are opposed to one axial surface of the anchor plates 33 and 33, respectively. Yes. Each of the cam surfaces 25a and 26a is inclined in a direction in which the depth dimension in the axial direction becomes smaller toward the circumferential end. Then, by sandwiching the balls 24, 24 between the driven cam surfaces 25a, 25a and the driving cam surfaces 26a, 26a, respectively, a pair of press means is provided. The loading cam devices 15b and 15b are configured. In order for these loading cam devices 15b and 15b to function, a retaining ring 35 is locked to the inner peripheral surface of the tip end portion (left end portion in FIG. 1) of the holding cylinder 31, and the anchor plates 33 and 33 are The distal end anchor plate 33 is prevented from retracting away from the proximal end (right side in FIG. 1) anchor plate 33. Also, the spring 34, which constitutes a pressing means together with the loading cam devices 15b and 15b, is formed between the anchor plate 33 on the base end side and the connecting portion 30a for connecting the holding cylinder 31 and the output shaft 19b. The anchor plate 33 on the proximal end side is elastically pressed toward the anchor plate 33 on the distal end side. It should be noted that when the pressing force generated by both the loading cam devices 15b, 15b becomes sufficiently large, the continuous portion 30a has an outer portion than the spring 34 so that the spring 34 is not completely crushed. The portion near the diameter is used as a stopper.

  Further, the outer peripheral surface of each intermediate roller 27a is a cylindrical surface in which the outer diameter of the intermediate portion in the axial direction does not change with respect to the axial direction. It is a partial conical convex surface inclined in the direction of decreasing diameter. The inclination angles of these partial conical convex surfaces are the same as the inclination angles of the inner peripheral surfaces of the annular roller elements 32, 32, and the partial conical convex surfaces and the inner peripheral surfaces of the annular roller elements 32, 32 are separated from each other. , Rolling contact (line contact) over a wide area. The cylindrical surface and the partial conical convex surface constituting the outer peripheral surface of each intermediate roller 27a are smoothly continuous by a curved surface having a partial arc shape in cross section. The cylindrical surface present in the axially intermediate portion of the outer peripheral surface of each intermediate roller 27a is in rolling contact with the outer peripheral surface of the sun roller 12b, but due to the presence of the curved surface, both ends of the rolling contact portion are Excessive surface pressure based on edge load is prevented from acting.

  The operation in the case where power is transmitted from the input shaft 12b to the output shaft 19b by the friction roller transmission 2b of this example configured as described above is as follows. First, the rotation of the input shaft 12b is transmitted to the annular roller elements 32 and 32 via the intermediate rollers 27a. Then, the two annular roller elements 32, 32 tend to be displaced in the circumferential direction with respect to the two anchor plates 33, 33, and the balls 24, 24 are connected to the drive side cam surfaces 26a, 26a and the The two annular roller elements 32, 32 approach each other on the driven cam surfaces 25a, 25a. As a result, the surface pressure of each traction portion, which is a rolling contact portion between the outer peripheral surface of each intermediate roller 27a, the outer peripheral surface of the sun roller 12b, and the inner peripheral surface of the annular roller 13b, increases. Further, it is possible to efficiently transmit power without causing excessive sliding in each of these traction portions and suppressing increase in rolling resistance due to excessive surface pressure of each of these traction portions.

In particular, according to the friction roller type transmission 2b of the present example, inevitable sliding friction caused by providing both the loading cam devices 15b and 15b can be suppressed low.
That is, in the case of the structure of this example, since both the loading cam devices 15b, 15b are provided on the annular roller 13b side, the inside of the annular roller elements 32, 32 from the rotational center of the annular roller 13b. The distance (rotation radius) to each traction portion, which is a rolling contact portion between the peripheral surface and the outer peripheral surface of each intermediate roller 27a, can be increased. For this reason, the inclination angle of the inner peripheral surfaces of the annular roller elements 32, 32 and the inclination angle of the partial conical convex surfaces at both ends of the outer peripheral surface of each intermediate roller 27a are determined according to the conventional structure described above or the sun roller of the prior invention. Even when the inclination angles of the outer peripheral surfaces of the elements 16a, 16b, and 16c (see FIGS. 6 and 9) are the same, the difference in peripheral speed between both ends of each of the traction portions can be kept small. As a result, the friction loss at each of these traction portions can be reduced, and the transmission efficiency of the friction roller transmission 2a can be easily ensured.

[Second Example of Embodiment]
FIG. 2 shows a second example of an embodiment of the present invention corresponding to claims 1 and 3. In the case of this example, the loading cam in which the pressing means for ensuring the surface pressure of each traction portion is arranged at a position sandwiching the pair of annular roller elements 32, 32a constituting the annular roller 13c from both sides in the axial direction. The device 15b and the spring 34 are provided. Among these, the configuration of the portion that presses the annular roller element 32 provided on the front end side of the holding cylinder 31 by the loading cam device 15b is the same as in the case of the first example of the above-described embodiment.

On the other hand, the annular roller element 32a provided on the proximal end side of the holding cylinder 31 is spline-engaged with the inner diameter side of the holding cylinder 31 so as to rotate together with the holding cylinder 31 and the holding cylinder 31. The cylinder 31 is supported so as to be displaced in the axial direction. Then, a spring 34 is provided between the base end face of the annular roller element 32a and the connecting portion 30a, and the base end side annular roller element 32a is elastically pressed toward the tip end side annular roller element 32. doing.
Since the configuration and operation other than the point that the loading cam device 15b is set as one set are the same as those in the first example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Third example of embodiment]
FIG. 3 shows a third example of an embodiment of the present invention corresponding to claims 1 and 4. In the case of this example, a pair of annular roller elements 32 a and 32 a constituting the annular roller 13 d are both spline-engaged with the inner peripheral surface of the holding cylinder 31. Then, a spring 34 is provided between the base end surface of the annular roller element 32 a provided on the base end side of the holding cylinder 31 and the connecting portion 30 a, and the base end side annular roller element 32 a is connected to the holding cylinder 31. It is elastically pressed toward the annular roller element 32a provided on the tip side. On the other hand, the annular roller 32a on the distal end side is brought into direct contact with a retaining ring 35 that is engaged with the inner peripheral surface of the distal end portion of the holding cylinder 31, so that the annular roller 32a on the proximal end side is brought into contact. To prevent displacement in the direction of retreating.
According to the structure of this example, the surface pressure of each traction portion cannot be adjusted according to the transmission torque, but if the magnitude of the transmission torque is substantially constant, as long as the elasticity of the spring 34 is sufficiently secured. It is possible to transmit power efficiently by suppressing friction loss.
Since the configuration and operation of the other parts are the same as those in the first example of the above-described embodiment, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  In each example shown in the figure, the friction roller type transmission is used as a speed reducer. However, if the input shaft and the output shaft are interchanged, they can be used as a speed increaser. Further, the present invention can be applied to a planetary roller type structure as shown in FIG.

DESCRIPTION OF SYMBOLS 1 Electric motor for vehicle drive 2, 2a, 2b Friction roller type reduction gear 3 Transmission 4 Rotation transmission device 5, 5a Input shaft 6 Output shaft 7 Drive side rotation shaft 8 Drive side rotation shaft 9a, 9b Gear transmission mechanism 10a, 10b Clutch mechanism 11 Differential gears 12, 12a, 12b Sun rollers 13, 13a, 13b, 13c, 13d Annular roller 14 Planetary rollers 15, 15a, 15b Loading cam devices 16a, 16b, 16c Sun roller element 17 Planetary shaft 18 Carriers 19, 19a , 19b Output shaft 20 Retaining ring 21 Support ring 22 Belleville spring 23 Cam plate 24 Ball 25, 25a Drive side cam surface 26, 26a Drive side cam surface 27, 27a Intermediate roller 28 Rotating shaft 29 Housing 30, 30a Connecting portion 31 Holding Tube 32, 32a Annular roller element 33 Anchor plate 34 Spring 35 Retaining ring

Claims (4)

An input shaft and an output shaft, a sun roller, an annular roller, a plurality of intermediate rollers, and a surface pressure applying device;
Each of the intermediate rollers is installed in an annular space between the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller so that at least rotation is possible. Rolling contact with the surface and the inner peripheral surface of the annular roller,
The surface pressure applying device is for ensuring the surface pressure of the rolling contact portion between the peripheral surfaces of these rollers,
The input shaft and the output shaft can rotate relative to each other and rotate together with any one of the rollers or any roller while being concentrically arranged with the sun roller and the annular roller. In the friction roller type transmission in which the input shaft and the output shaft are coupled to different elements to two types of elements selected from among the supporting members
The surface pressure applying device is provided on the annular roller side, and increases the surface pressure of each rolling contact portion by pressing each intermediate roller inward in the radial direction of the annular roller. A friction roller transmission characterized by having all the requirements (A) to (E).
(A) The annular roller is paired with an inner peripheral surface of a holding cylinder provided concentrically with the first rotating shaft at an end of the first rotating shaft that is one of the input shaft and the output shaft. The annular roller element is configured so as to be rotatable with the holding cylinder and capable of moving toward and away from each other.
(B) A pressing means is provided between the holding cylinder and at least one of the annular roller elements to press the annular roller elements toward each other.
(C) The inner peripheral surfaces of the annular roller elements are partially conical concave surfaces that are inclined in a direction in which the inner diameter increases toward the distal end surface, which is a surface of the annular roller elements facing each other.
(D) The outer peripheral surface of each of the intermediate rollers is a cylindrical surface in which the outer diameter of the intermediate portion in the axial direction does not change with respect to the axial direction, and the outer diameter increases toward the both end surfaces in the axial direction of the respective intermediate rollers. It is a partial conical convex surface that is inclined in the direction of decreasing.
(E) Among the sun rollers, at least a portion where the intermediate portion in the axial direction of the outer peripheral surface of each intermediate roller may be in rolling contact is a cylindrical surface whose outer diameter does not change in the axial direction.   The pressing means is a pair of loading cam devices disposed at positions sandwiching the annular roller elements from both sides in the axial direction, and both the loading cam devices are respectively disposed on the inner peripheral surface of the holding cylinder. Toward the circumferential end formed on each of a plurality of anchor plate axially facing one face and the base end face of the annular roller element, which are opposed to each other and supported by an anchor plate that can be rotated in synchronization with each other. The cam surface is inclined in a direction in which the depth dimension with respect to the axial direction becomes smaller, and a plurality of rolling elements sandwiched between these cam surfaces, and constitutes both the loading cam devices 1 One anchor plate of the pair of anchor plates is supported on the inner peripheral surface of the holding cylinder in a state in which axial displacement in the direction of retracting from the other anchor plate is prevented. The friction roller type speed change according to claim 1, further comprising a spring that elastically presses the other anchor plate toward the one anchor plate between the other anchor plate and the holding cylinder. Machine.   The pressing means is a loading cam device and a spring disposed at a position sandwiching the two annular roller elements from both sides in the axial direction. Of these, the loading cam device is disposed on the inner peripheral surface of the holding cylinder on the both circumferential surfaces. An anchor plate that is supported so as to be able to rotate in synchronization with the holding cylinder in a state in which displacement in a direction away from one of the annular roller elements is prevented, and one axial surface of the anchor plate facing each other And a cam surface inclined in a direction in which the depth dimension with respect to the axial direction becomes smaller toward the circumferential end, and each of these cam surfaces. A plurality of rolling elements sandwiched between them, wherein the spring is provided between a base end surface of the other annular roller element of the annular roller elements and the holding cylinder. Is it is intended to elastically pressed toward the other of the annular roller elements on the one annular roller element, friction roller type transmission according to claim 1.   The pressing means is a spring, and one annular roller element of the two annular roller elements is supported inside the holding cylinder portion in a state in which displacement in a direction away from the other annular roller element is prevented, The spring is provided between a base end surface of the other annular roller element of the annular roller elements and the holding cylinder, and elastically moves the other annular roller element toward the one annular roller element. The friction roller transmission according to claim 1, wherein the friction roller transmission is pressed against the friction roller.

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