JPH1172152A - Friction roller type transmission - Google Patents

Abstract

(57) [Problem] To realize a structure that can be miniaturized and can obtain high transmission efficiency irrespective of fluctuation of torque to be transmitted. An inner ring (33) having an outer peripheral surface having a conical convex surface is supported at an intermediate portion of an input shaft (26) so as to be displaceable in the axial direction. Between the outer peripheral surface 34 of the inner race 33 and the inner peripheral surface 36 of the fixed outer race 35, transmission rollers 40 each having a hollow tapered roller shape are sandwiched. These transmission rollers 4
A pivot 38 pivoted at zero is coupled to the output shaft 30. or,
A loading cam device 42 is provided between the input shaft 26 and the inner ring 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a friction roller type transmission which transmits rotational motion while reducing or increasing speed by being incorporated in various types of mechanical devices. This realizes a structure having the above.

[0002]

2. Description of the Related Art A friction roller type transmission generates less noise even when operated at a high speed than a gear type transmission such as a planetary gear type. For this reason, a structure in which a friction roller type transmission is assembled to an output portion of an electric motor and used as a speed reducer, and the rotational movement of the electric motor is reduced and the torque is increased is described in, for example, Japanese Patent Application Laid-Open No. Hei 8-210455. Have been. 8 and 9 are described in this publication.
1 shows an electric motor with a friction roller type reduction gear;

[0003] A motor case 2 constituting the electric motor 1
Consists of a bottomed cylindrical case body 3 and a lid 4 that closes an opening of one end (the lower end in FIG. 8) of the case body 3. The rotation drive shaft 5 is rotatably supported at the center of the inside of the motor case 2. A stator 6 is fixed on the inner peripheral surface of the case body 3, and a rotor 7 is fixed on a portion of the intermediate peripheral surface of the rotary drive shaft 5 facing the inner peripheral surface of the stator 6. The rotation shaft 5 is freely rotatable on the basis of the energization of. A planetary roller type speed reducer 8 is provided on the outer surface of the lid 4 (the lower surface in FIG. 8).

The planetary roller type speed reducer 8 has one end (the lower end in FIG. 8) of the rotary drive shaft 5 which is the first rotary shaft.
The portion protruding from the outer surface of the lid 4 functions as the center roller 9. The center roller 9 is concentric with the rotation drive shaft 5 and has an outer peripheral surface as a first cylindrical surface 10. An outer ring 11 is disposed around the center roller 9 so as to be rotatable relative to the center roller 9.
In the illustrated example, the outer ring 11 is fitted inside a cylindrical wall portion 12 formed near the outer diameter of the outer surface of the lid 4, and the outer ring 11 is fixed by a plurality of fixing bolts 21, 21.
Is fixed to the lower surface of the lid 4. That is, in the illustrated example, the center roller 9 is fixed inside the fixed outer ring 11.
Rotates. The inner peripheral surface of such an outer ring 11 is a second cylindrical surface 13.

In the annular space 14 between the second cylindrical surface 13 and the first cylindrical surface 10, a part of a plurality of (four in the illustrated example) pivots 15, 15 are inserted. ing. These pivots 15 are arranged in parallel with the rotary drive shaft 5, respectively. Further, planetary rollers 16, 16 are rotatably supported by radial needle bearings 17, 17 at portions of the respective pivots 15, 15 which are located inside the annular space 14. ing. The outer peripheral surface of each of the planetary rollers 16 is a third cylindrical surface 18 that comes into contact with the first cylindrical surface 10 and the second cylindrical surface 13, respectively. Further, portions protruding from the annular space 14 at the ends of the pivots 15 and 15 are connected and fixed to a ring-shaped connecting plate 19. The base end of the output shaft 20, which is the second rotating shaft, is fixedly connected to the center of the connecting plate 19. This output shaft 20
Is rotatable by a pair of ball bearings 25, 25 inside a cylindrical portion 24 provided at the center of a cover 23 fixedly connected to the distal end of the cylindrical wall portion 12 by a plurality of connecting bolts 22, 22. I support it.

The operation of the planetary roller type electric motor with a speed reducer constructed as described above is as follows. When the rotation drive shaft 5 rotates based on the energization of the stator 6,
Based on the friction between the first cylindrical surface 10 of the center roller 9 and the third cylindrical surfaces 18 of the planetary rollers 16, these planetary rollers 16, 16 move around the center roller 9. Revolves while rotating. This revolving motion is transmitted to the output shaft 20 via the pivots 15 and 15 and the connecting plate 19, and the output shaft 20 rotates at a lower speed than the rotary drive shaft 5.

In order to secure the transmission efficiency of the planetary roller type speed reducer 8, in order to prevent slippage between the third cylindrical surfaces 18, 18 and the first and second cylindrical surfaces 10, 13, Therefore, it is necessary to secure the contact pressure between these cylindrical surfaces 18, 10, and 13. In order to secure this contact pressure, in the case of the structure shown in FIGS.
16 is pressed into an annular space 14 between the first cylindrical surface 10 and the second cylindrical surface 13. That is, the outer ring 11 provided with the second cylindrical surface 13 is heated to
The respective planetary rollers 16, 16 are inserted into the annular space 14 in a state where the diameter of the second cylindrical surface 13 is expanded by thermally expanding. After the insertion, if the temperature of the outer race 11 is reduced and the diameter of the second cylindrical surface 13 is reduced, the cylindrical surfaces 18, 10, 13 are connected to each other by the components 9, 11, 11 of the planetary roller type speed reducer 8. , 16 based on the elastic deformation
Contact with sufficiently large pressure. Further, although not shown in the drawings, the structure of the planetary roller alone can be applied, for example, in Japanese Unexamined Patent Application Publication No.
As described in JP-A-226509 and the like, it has been widely known.

In the above-described known planetary roller type speed reducer 8, it is difficult to increase the transmission efficiency over the entire range. The loss was inevitable. The reason is as follows. That is, in the case of the above-mentioned conventional planetary roller type speed reducer 8, in order to secure the transmission efficiency of the planetary roller type speed reducer 8, the outer peripheral surface of the center roller 9 and the inner peripheral surface of the outer ring 11 are formed as described above. Between each of the planetary rollers 16, 1
6, and the cylindrical surface 1 of each of the members 9, 11, 16
The contact pressure between 0, 13, and 18 is secured.

On the other hand, assuming that the contact pressure is constant, the larger the torque transmitted through the planetary roller type speed reducer 8, the more the cylindrical surfaces 10, 13, and 18 come into contact with each other. The part becomes slippery. For this reason, conventionally, the contact pressure has been regulated (increased) so that the contact portions do not slip even when the torque transmitted through the planetary roller type speed reducer 8 is maximized. However, when the contact pressure between the peripheral surfaces that are in rolling contact is increased, the rolling resistance increases, and the power loss in the planetary roller type speed reducer 8 increases. That is, even if the torque transmitted via the planetary roller type speed reducer 8 is small and there is no possibility that the above-mentioned contact portions may slip even if the contact pressure is low, excessive contact between these contact portions may occur. The contact pressure is applied, and the internal loss (power transmission loss) of the planetary roller type speed reducer 8 increases.

On the other hand, Japanese Patent Application Laid-Open No. 47-26555 discloses a method in which a first cylindrical surface is provided on the outer peripheral surface of an inner ring whose diameter can be expanded and contracted, and the outer diameter of the inner ring is determined by the torque to be transmitted. A planetary roller type speed reducer that expands and contracts according to the size is described. According to such a structure, the contact pressure between the third cylindrical surface provided on the outer peripheral surface of the planetary roller and the first and second cylindrical surfaces is changed in accordance with the torque to be transmitted, thereby reducing the planetary roller type deceleration. The internal loss of the machine can be reduced.

[0011]

Problems to be Solved by the Invention
In the case of the planetary roller type speed reducer described in Japanese Patent Publication No. 5 (1993), since a torque cam for expanding and contracting the inner ring is incorporated on the inner diameter side of the inner ring in accordance with the magnitude of the torque to be transmitted, the diameter of the inner ring increases. . When increasing the reduction ratio of the planetary roller type speed reducer, it is necessary to reduce the outer diameter of the first cylindrical surface provided on the outer peripheral surface of the inner ring, so it is not preferable that the diameter of the inner ring is increased. . In other words, it is very difficult to incorporate a torque cam on the inner diameter side of the inner ring when considering that a planetary roller type reduction gear that can obtain a required reduction ratio is installed in a limited space. SUMMARY OF THE INVENTION In view of such circumstances, the present invention has been conceived to realize a friction roller type transmission that can be configured in a small size and that can obtain good transmission efficiency even in a situation where the torque to be transmitted fluctuates.

[0012]

SUMMARY OF THE INVENTION A friction roller type transmission according to the present invention is disposed concentrically with a first rotating shaft and rotates relative to the first rotating shaft. A second rotating shaft, an inner ring having a conical convex surface on an outer circumferential surface rotatably supported on the outer circumferential surface of the first rotating shaft together with the first rotating shaft, and concentric with the inner ring around the inner ring. An outer ring having an inner peripheral surface with a conical concave surface, a plurality of pivots inserted between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and rotatable around each of these pivots. A plurality of tapered roller-shaped transmission rollers each of which is supported and whose outer peripheral surface is in contact with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and a base end of the plurality of pivots. A first support member for connecting and supporting, a second support member for supporting the outer ring, From the first and second support members, a coupling member for coupling one of the support members and the second rotation shaft, between the first rotation shaft and the second rotation shaft. And pressing means for pressing at least one of the inner ring and the outer ring toward the plurality of transmission rollers in the axial direction during the power transmission. The other of the first and second support members is fixed.

[0013]

During operation of the friction roller type transmission of the present invention constructed as described above, the pressing means directs at least one of the inner race and the outer race toward the transmission roller to transmit the transmission between the first and second rotating shafts. Press with a force corresponding to the applied torque. Therefore, good transmission efficiency can be obtained even when the torque to be transmitted fluctuates. In addition, since the pressing means is disposed at a position shifted in the axial direction with respect to the inner ring or the outer ring, the provision of the pressing means does not limit the diameters of the inner ring and the outer ring.

[0014]

FIG. 1 shows a first example of an embodiment of the present invention, which corresponds to only claim 1 of the present invention. The input shaft 26, which is the first rotating shaft, is connected to the frame 2 of various mechanical devices.
A rolling bearing such as a radial needle bearing 29 is rotatably supported inside a housing 28 fixed to a fixed portion such as 7 by screws. Also, the output shaft 30, which is the second rotating shaft, is connected to the front end of the input shaft 26 (the left end in FIG. 1).
And is arranged concentrically with the input shaft 26. A cylindrical portion 31 concentric with the output shaft 30 is provided at the base end of the output shaft 30.
Is fixed. By providing a pair of rolling bearings, such as a pair of deep groove ball bearings 32, 32, between the inner peripheral surface of the cylindrical portion 31 and the outer peripheral surface of the distal end portion of the input shaft 26, the input shaft 26 The relative rotation of the output shaft 30 is free.

An inner ring 33 is supported on the outer peripheral surface of the intermediate portion of the input shaft 26 by a radial needle bearing 54 so as to be rotatable with respect to the input shaft 26 and displaceable in the axial direction. The inner ring 33 has a shape like an inner ring constituting a tapered roller bearing, and has an outer peripheral surface 34 having a conical convex surface. On the other hand, an outer ring 35 is fixedly fitted inside the housing 28 in a state of being concentric with the inner ring 33 around the inner ring 33 on the inner peripheral surface of the intermediate portion. Therefore, in the case of this example, the housing 28 corresponds to the second support member. The outer ring 35 has a shape like an outer ring constituting a tapered roller bearing, and has an inner peripheral surface 36 having a conical concave surface.

An outer flange-like mounting portion 37 corresponding to a first support member is fixedly provided on the outer peripheral surface of the open end (the right end in FIG. 1) of the cylindrical portion 31. Therefore, in the case of this example, the cylindrical portion 31 corresponds to a connecting member. And
The base portion (left end in FIG. 1) of a plurality (generally about 3 to 4) of pivots 38 is supported and fixed to the mounting portion 37. The pivot 38 has a circular cross section and is formed into an overall "K" shape by bending an intermediate portion at an obtuse angle, and each tip (the right end in FIG. 1) is attached to the inner peripheral surface 3 of the outer ring 35.
6 is inserted into an annular space 39 between the inner ring 33 and the outer peripheral surface 34 of the inner ring 33. In this state, the center line α of the distal end of each pivot 38 is located at a position that bisects the intersection angle between the generatrix of the inner peripheral surface 36 and the generatrix of the outer peripheral surface 34.

A transmission roller 40 is rotatably supported by a rolling bearing such as the radial needle bearing 17 at the distal end of each pivot 38 as described above. Each of the transmission rollers 40 has a shape in which a tapered roller constituting a tapered roller bearing is hollow, and a support hole 41 having a circular cross section is formed at the center. The radial needle bearing 17 is provided between the inner peripheral surface of the support hole 41 and the outer peripheral surface of the tip of the pivot 38. Further, in such a state that the transmission roller 40 is rotatably supported on the distal end of each of the pivots 38, two positions on the part of the outer peripheral surface of each of the transmission rollers 40 opposite to the cross-section in the diameter direction are inside the outer ring 35. The peripheral surface 36 and the outer peripheral surface 34 of the inner ring 33 are in contact with each other over substantially the entire length.

Further, a loading cam device 42 as a pressing means is provided between the input shaft 26 and the inner ring 33 so that power can be freely transmitted between the input shaft 26 and the output shaft 30. In addition, along with the power transmission, the inner ring 33 is directed toward the plurality of transmission rollers 40, and is capable of being pressed in the axial direction (rightward in FIG. 1). In order to constitute such a loading cam device 42, a cam plate 43 is provided at a portion of the intermediate portion of the input shaft 26 facing the large-diameter side end surface 45 (the left end surface in FIG. 1) of the inner ring 33, and a spline engagement is provided. Thus, the input shaft 26 is supported so as to be freely displaceable in the axial direction. The large diameter end face 45 and the large diameter end face 4
5, one side of the cam plate 43 (right side in FIG. 1)
The cam surfaces 44 each have irregularities extending in the circumferential direction (in FIG. 1, the irregularities extending in the circumferential direction are shown as the irregularities extending in the diameter direction for the sake of explanation). 44 are formed. A plurality (for example, about 3 to 5) of these two cam surfaces 44, 44 and the large diameter side end surface 45 are provided between the two cam surfaces 44, 44 and the large diameter side end surface 45.
The center axis of each of the pressing rollers 46 and the diameter direction of the cam plate 43 coincide with each other (FIG. 1 shows the center axis and the diameter direction orthogonal to each other for the sake of explanation). However, they are actually matched), and they are held in a state of being freely rolled by a retainer (not shown).

An outward flange-shaped flange portion 55 is fixedly provided at an intermediate portion of the input shaft 26 at a position opposite to the inner ring 33 with respect to the cam plate 43 by screwing a nut or the like. . Then, between one side surface (the right surface in FIG. 1) of the flange portion 55 and the other surface (the left surface in FIG. 1) of the cam plate 43,
An elastic member 48 such as oil-resistant rubber or a compression coil spring is sandwiched. This elastic member 48 is free in the axial direction (FIG. 1).
(Left-right direction of the transmission roller 40) is increased, and the inner ring 33 has elasticity in a direction to approach the transmission rollers 40. In addition, the distal end surface of a stopper 57 provided on the outer periphery of one side of the flange portion 55 is made to closely approach the other surface of the cam plate 43. The elastic member 48 serves to apply a preload to each of the pressing rollers 46, and
Reference numeral 7 serves to secure a force for pressing each of the pressing rollers 46 between the cam surfaces 44, 44 regardless of the presence of the elastic member 48. The housing 28
A base end portion of a cover 49, which is formed in a cylindrical shape with a crank-shaped cross section, is fixedly connected to the outer peripheral portion on one side.
This cover 49 covers the periphery of the mounting portion 37 to prevent foreign matter from entering the inside of the friction roller type transmission, and to prevent the lubricating oil such as traction grease filled in the friction roller type transmission from flowing outside. To prevent leakage.

During the operation of the friction roller type transmission of the present invention constructed as described above, it is generated on the basis of the rotation of the input shaft 26 and the inner ring 33 as in the case of the conventional structure shown in FIGS. Then, the orbital motion of each of the transmission rollers 40 is taken out, and the output shaft 30 is rotated at a lower speed than the input shaft 26. When transmitting the rotational force from the input shaft 26 to the output shaft 30 in this way, the loading cam device 42
Is directed toward the transmission roller 40 and pressed with a force having a magnitude corresponding to the torque transmitted between the input shaft 26 and the output shaft 30, and at the same time, the rotation of the input shaft 26 is transmitted to the inner ring 33. That is, when the input shaft 26 is rotationally driven by a driving source such as an electric motor (not shown), the plurality of pressing rollers 46 constituting the loading cam device 42 ride on the convex portions of the cam surfaces 44, 44. Each of the pressing rollers 46 connects the inner ring 33 to the corresponding transmission roller 4.
Press towards zero. As a result, each of these transmission rollers 4
0, the outer peripheral surface 34 of the inner race 33 and the outer race 35
The contact pressure of the contact portion with the inner peripheral surface 36 increases. Further, the rolling surfaces of the plurality of pressing rollers 46 and the two cam surfaces 44,
The rotation of the cam plate 43 that rotates together with the input shaft 26 is transmitted to the inner ring 33 based on the pressing with the input shaft 26, and the inner ring 33 rotates at the same speed as the input shaft 26.
At this time, the inner ring 33 is slightly displaced in the axial direction, and accordingly, the transmission rollers 40 are also displaced in the axial direction of the inner ring 33. Absorption is caused by gaps and elastic deformation of the pivots 38.

Each of the pressing rollers 46 is connected to both of the cam surfaces 4.
The degree of riding on the projections 4 and 44 changes according to the magnitude of the torque applied from the input shaft 26 to the cam plate 43. That is, the greater the torque, the greater the extent to which each of the pressing rollers 46 rides on the convex portions of the two cam surfaces 44, 44, and the outer peripheral surfaces of the transmission rollers 40, the outer peripheral surface 34 of the inner ring 33, and Inner peripheral surface 3 of outer ring 35
The contact pressure with the pressure 6 increases. On the other hand, when the torque is small, each of the pressing rollers 46 is
The degree of riding on the convex portion of the roller 44 becomes smaller, and the contact pressure between the outer peripheral surface of each transmission roller 40, the outer peripheral surface 34 of the inner ring 33, and the inner peripheral surface 36 of the outer ring 35 decreases. As described above, the contact pressure needs to be increased as the torque to be transmitted between the input shaft 26 and the output shaft 30 increases. Therefore, the friction roller type transmission incorporating the loading cam device 42 acting as described above can always obtain good transmission efficiency even in a situation where the torque to be transmitted fluctuates.

In addition, the loading cam device 42
Is disposed at a position displaced in the axial direction with respect to the inner ring 33 or the outer ring 35. Therefore, by providing the loading cam device 42, the diameters of the inner ring 33 and the outer ring 35 are not limited. In other words, the outer diameter of the inner ring 33 can be sufficiently reduced regardless of the presence of the loading cam device 42 without increasing the diameter of the entire friction roller transmission. Therefore, a friction roller type transmission having a required reduction ratio and a small diameter can be realized.

Next, FIG. 2 shows a second example of the embodiment of the present invention, which also corresponds only to the first aspect. In the case of the first example described above, the present invention is applied to a planetary friction roller type transmission in which a plurality of transmission rollers 40 revolve around the pivot 38 while revolving around the inner ring 33. On the other hand, in the case of this example, each transmission roller 40 is connected to each pivot 38.
The present invention is applied to a non-planetary-type friction roller type transmission in which the rotation only occurs around the periphery of the roller and does not revolve. In the case of this example based on such a type difference, each of the pivots 3
8 is supported and fixed to a fixed portion such as the frame 27 via an annular support bracket 50 corresponding to a first support member. The outer race 35 is internally fitted and fixed to the distal end of a cylindrical holder 51 corresponding to a second support member. The holder 51 has a mounting portion 37 corresponding to a coupling member.
And, it is connected and fixed to the base end of the output shaft 30 via the cylindrical portion 31. Therefore, the output shaft 30 and the outer ring 35 rotate in synchronization with each other. Further, in the case of this example, the cam surface is not formed on the large-diameter side end surface 45 of the inner ring 33, but is simply a flat surface. Therefore, in the case of this example, the input shaft 26
Is transmitted to the inner ring 33 based on frictional engagement between the rolling surfaces of the plurality of pressing rollers 46 and the flat surface formed on the large-diameter end surface 45.

In the case of the present embodiment configured as described above, the input shaft 2
The rotation of 6 is transmitted from the inner ring 33 to the plurality of transmission rollers 40, and the transmission rollers 40 rotate around the respective pivots 38. The rotation of each transmission roller 40 is as follows.
The power is transmitted to the outer ring 35 to rotate the outer ring 35 and the output shaft 30 at a lower speed than the input shaft 26. Also in the case of the present embodiment configured and operated as described above, the outer peripheral surfaces of the transmission rollers 40, the outer peripheral surface 34 of the inner race 33, and the inner peripheral surface 3 of the outer race 35 are operated by the loading cam device 42.
6 is increased as the torque to be transmitted between the input shaft 26 and the output shaft 30 increases, so that good transmission efficiency can always be obtained even in a situation where the torque to be transmitted fluctuates. The other configurations and operations are the same as those in the first example described above, and therefore, the same parts are denoted by the same reference numerals, and redundant description will be omitted.

Next, FIG. 3 shows a third example of the embodiment of the present invention, which also corresponds only to the first aspect. In practicing the present invention, the pressing means such as the loading cam device 42 may be provided on the input shaft side or on the output shaft side. Further, the friction roller type transmission of the present invention can be used not only as a speed reducer but also as a speed increaser. Therefore, in the first example and the second example described above, the input shaft 26
And the output shaft 30 can be exchanged and used as it is as a gearbox. However, in order to more effectively prevent the contact portion between the outer peripheral surface of the transmission roller 40 and the outer peripheral surface 34 of the inner race 33 and the inner peripheral surface 36 of the outer race 35 from slipping, and to obtain good transmission efficiency immediately after the start of operation. Preferably, the pressing means is provided on the input shaft side. In view of such circumstances, in the present example, when the non-planetary friction roller type transmission as in the second example described above is used as a gearbox, good transmission efficiency can be obtained immediately after the start of operation. Provides structure.

In order to achieve such an object, in the case of the present embodiment, a base end portion of the input shaft 26a corresponding to the second rotating shaft is provided with:
The holder 51a corresponding to the second support member is connected and fixed via the cylindrical portion 31 and the mounting portion 37 corresponding to the connecting member. The outer ring 35 is provided on the inner peripheral surface of the holder 51a.
a is supported by a rolling bearing such as a radial needle bearing 54a so as to be freely rotated with respect to the holder 51a and displaceable in the axial direction. A cam plate 43a is supported by a spline engagement on a portion of the inner peripheral surface of the holder 51a facing the large-diameter end surface 52 of the outer ring 35a so as to be freely movable only in the axial direction with respect to the holder 51a. I have. And one side of this cam plate 43a (left side in FIG. 3)
Cam surface 44a provided on the outer ring 35a and the large diameter side end surface 5 of the outer ring 35a.
A plurality of pressing rollers 46 are sandwiched between the two and constitute a loading cam device 42a as a pressing device.
Further, one surface (left surface in FIG. 3) of an inward flange-shaped flange portion 56 formed on the inner peripheral surface of the tip portion (right end portion in FIG. 3) of the holder 51a and the other surface (right surface in FIG. 3) of the cam plate 43a. An elastic member 48a is provided between the outer ring 35a and the cam plate 43a to elastically and lightly press the cam plate 43a toward the large-diameter end surface 52 of the outer ring 35a. On the other hand, the inner ring 33a is externally fixed to the outer peripheral surface of the intermediate portion of the output shaft 30a corresponding to the first rotation shaft so as not to move in the axial direction and the rotation direction with respect to the output shaft 30a. . During the operation of the loading cam device 42a as described above, the cam plate 43a moves axially rearward (to the right in FIG. 3) as the plurality of pressing rollers 46 ride on the cam surface 44a. In this case, the leading edge (right edge in FIG. 3) of the cylindrical stopper 57a formed on the inner peripheral edge of the other surface side (right surface side in FIG. 3) of the cam plate 43a is connected to the flange portion 56.
, The pressing force of each of the pressing rollers 46 is secured.

In the case of the present embodiment configured as described above, the input shaft 2
6a is rotated by the loading cam device 42a and the outer race 3
5a to the plurality of transmission rollers 40, and the transmission rollers 40 rotate around the respective pivots 38. Such rotation of each transmission roller 40 is transmitted to the inner ring 33a to rotate the inner ring 33a and the output shaft 30a at a higher speed than the input shaft 26a. Also in the case of this example configured and operated in this manner, the loading cam device 42a
, The contact pressure between the outer peripheral surface of each transmission roller 40, the outer peripheral surface 34 of the inner ring 33a, and the inner peripheral surface 36 of the outer ring 35a should be transmitted between the input shaft 26a and the output shaft 30a. The higher the torque is, the higher the torque is, so that good transmission efficiency is always obtained even in the situation where the torque to be transmitted fluctuates. Other configurations and operations are the same as those in the above-described second example. Therefore, the same reference numerals are given to the same parts, and the duplicate description will be omitted.

Next, FIG. 4 corresponds to claims 1-2.
14 shows a fourth example of an embodiment of the present invention. In the case of the above-described first to third examples, the loading cam devices 42 and 42a as the pressing means are all provided in a space where the power transmission unit including the inner ring 33, the outer ring 35a and the respective transmission rollers 40 is installed. I have. On the other hand, in the case of the present embodiment, the pressing means is provided outside the space in which the power transmission unit is installed, so that the space in which the power transmission unit is installed is further reduced. In order to achieve such an object, in the case of this example, the first housing element 5 in which the input shaft 26 as the first rotating shaft is fixed to a frame or the like of various mechanical devices.
Inside the housing 8, a radial needle bearing 29 supports the first housing element 58 so as to be freely rotatable and displaceable in the axial direction. Further, the output shaft 30, which is the second rotating shaft, is supported by a radial needle bearing 60 inside the second housing element 59 fixed to the frame or the like so as to freely rotate only relative to the input shaft 26. . And, in the space 61 existing between the first housing element 58 and the second housing element 59,
A power transmission unit 62 for transmitting a rotational force between the input shaft 26 and the output shaft 30 is provided.

That is, the power transmission section 62 is attached to the outer peripheral surface of the portion of the input shaft 26 which is inserted into the space 61 at the tip end.
Are fixedly connected to each other. In the case shown in the figure, the inner ring 33b is spline-engaged with the tip of the input shaft 26, and is screwed to a portion of the input shaft 26 projecting from one end face (the left end face in FIG. 4) of the inner ring 33b. The input shaft 26 is fixed by the nut 63 tightened and tightened.
By restraining it on the step surface 64 formed on the outer peripheral surface of the input shaft 26, relative rotation with respect to the input shaft 26 and displacement in the axial direction are impossible. On the other hand, the outer race 35b is internally fitted and fixed to the base end (the left end in FIG. 4) of the bottomed cylindrical mounting portion 65. That is, the outer ring 35b has one end face (the left end face in FIG. 4).
4 is abutted against the inner surface (the right side surface in FIG. 4) of the annular portion 66 constituting the mounting portion 65, and is internally fitted and fixed to the cylindrical portion 67 fixed to the outer peripheral edge of the mounting portion 65. . And
The output shaft 30 is rotated in synchronization with the outer ring 35b by connecting the inner peripheral edge of the ring portion 66 to the base end of the output shaft 30. Therefore, in the case of the present example, the mounting portion 65 functions as both the second support member and the coupling member. In the illustrated example, a rolling bearing such as a thrust needle bearing 68 is provided between the second housing element 59 and the ring portion 66. Each pivot 38 for rotatably supporting a plurality of transmission rollers 40.
Is supported and fixed to the inner side surface (the left side surface in FIG. 4) of the first housing element 58 corresponding to the first support member.

Further, a loading cam device 42b is provided outside (in the right side of the first housing element 58) outside the space 61 in the axial direction of the input shaft 26.
In the case of this example, the loading cam device 42b includes a base end (the right end in FIG. 4) of the input shaft 26 and the input shaft 2
6 is provided concentrically with the distal end of a rotary drive shaft 5 that constitutes a conductive motor (not shown). The loading cam device 42b allows the power transmission between the rotary drive shaft 5 and the input shaft 26 to be free, and the inner ring 33b fixed to the distal end portion of the input shaft 26 with the power transmission. The transmission rollers 40 can be pressed axially (to the left in FIG. 4). In order to constitute such a loading cam device 42b, the input shaft 26
A disk 69 is provided at the base end of the motor, and a cam plate 43b is provided at the front end of the rotary drive shaft 5. Of these, the cam plate 43b is supported on the tip of the rotary drive shaft 5 by a spline engagement or the like so as to be displaceable in the axial direction of the rotary drive shaft 5. Then, the cam surface 44b formed on one side (the left side in FIG. 4) of the cam plate 43b and the disc 69
Between the flat surface 71 formed on one side (the right side in FIG. 4)
A plurality of pressing rollers 46 are sandwiched.

An outward flange-shaped flange portion 70 is fixedly provided on the outer peripheral surface of the rotary drive shaft 5 near the front end. Then, one side of the flange 70 (the left side in FIG. 4) and the cam plate 4
An elastic member 48a is provided between the rear surface of 3b (the right surface in FIG. 4) and the cam plate 43b is lightly pressed toward the flat surface 71 of the disk 69. Also in the case of the present embodiment, a cylindrical stopper 57 is provided on the outer peripheral edge on the back side of the cam plate 43b, and the flat portion, which is a portion for holding the pressing rollers 46 when the loading cam device 42b is operated, is provided. Face 7
The gap between the cam surface 1 and the cam surface 44b is prevented from becoming too wide. A thrust needle bearing 73 and a radial needle bearing 74 are provided between the third housing element 72 fixed to a fixed portion such as the frame and the intermediate portion of the flange 70 and the rotary drive shaft 5, respectively. Provided. The intermediate portion of the rotary drive shaft 5 is supported by the third housing element 72 only rotatably by these two bearings 73 and 74.

During the operation of the friction roller type transmission of the present embodiment, the rotation of the rotary drive shaft 5 is transmitted to the input shaft 26 via the loading cam device 42b. Then, the rotation of the input shaft 26 is
To the plurality of transmission rollers 40, and each of these transmission rollers 40 rotates around each pivot 39. The rotation of each of the transmission rollers 40 is transmitted to the outer ring 35b to cause the outer ring 3b to rotate.
5b and the output shaft 30 are rotated at a lower speed than the input shaft 26. When transmitting the rotational force from the input shaft 26 to the output shaft 30 in this manner, the loading cam device 42b
Turns the inner ring 33 b connected to the tip of the input shaft 26 toward each of the transmission rollers 40, and
Pressing with a force of a magnitude corresponding to the torque transmitted between zero. Therefore, also in the case of the present example, the contact pressure between the outer peripheral surface of each transmission roller 40, the outer peripheral surface 34 of the inner ring 33b, and the inner peripheral surface 36 of the outer ring 35b is input by the operation of the loading cam device 42b. The higher the torque to be transmitted between the shaft 26 and the output shaft 30, the higher the torque. Because of this,
Even in situations where the torque to be transmitted fluctuates, good transmission efficiency can always be obtained. In addition, in the case of this example, the loading cam device 42b is provided outside the space 61 in which the power transmission unit 62 is installed. Therefore, with the provision of the loading cam device 42b, not only the diameters of the inner ring 33b and the outer ring 35b are not limited, but also the axial dimension of the power transmission unit 62 does not increase. As a result, a friction roller type transmission having a required gear ratio and a smaller diameter can be realized.

Next, FIG. 5 shows a fifth embodiment of the present invention, which also corresponds to claims 1 and 2. While the above-described fourth example applies the present invention to a friction roller type transmission having a non-planetary type power transmission portion 62a, in the case of this example, the present invention is applied to a planetary type friction roller type transmission. The invention has been applied. In the case of the present example based on such a type difference, the base end of each pivot 38 is supported and fixed to a ring-shaped flange 75 fixed to the base end of the output shaft 30. Therefore,
In the case of the present example, the flange 75 functions as both the first support member and the coupling member. Further, the outer ring 35b is internally fitted and fixed to a second housing element 59a corresponding to a second support member.

During the operation of the friction roller type transmission of this embodiment having the above-described structure, the frictional transmission is generated based on the rotation of the input shaft 26 and the inner ring 33b as in the case of the conventional structure shown in FIGS. Take out the revolving motion of each transmission roller 40,
The output shaft 30 is rotated at a lower speed than the input shaft 26. Also in the case of the present embodiment configured and operated in this manner, the loading cam device 42b does not affect the fluctuation of the torque transmitted between the input shaft 26 and the output shaft 30 and has a good transmission efficiency. Can be obtained. Other configurations and operations are the same as those of the above-described fourth example, and therefore, the same reference numerals are given to the same parts, and the overlapping description will be omitted.

Next, FIG. 6 shows a sixth embodiment of the present invention, which also corresponds to claims 1 and 2. In the case of this example, a solenoid 76 is used as a pressing means for pressing the input shaft 26 in the axial direction, instead of the loading cam device 42b (FIGS. 4 and 5). This solenoid 7
6 is provided outside the space 61 in which the power transmission unit 62 is installed. Such a solenoid 76 is made of a magnetic material or a permanent magnet plunger 77 externally fitted and fixed to an intermediate portion of the input shaft 26, and a coil provided around the plunger 77 and supported and fixed to a fixed portion (not shown). 84.
The plunger 77 is displaced to one side in the axial direction (left side in FIG. 6) with the energization of the coil 84, and the input shaft 26
To the output shaft 30 side. At the same time, the inner ring 33 b fixed to the tip of the input shaft 26 is connected to each transmission roller 4.
Press in the axial direction toward zero. The pressing force of the solenoid 76 can be adjusted by changing the amount of current supplied to the coil 84. Therefore, also in the case of this example, a good transmission efficiency can be obtained without being affected by the fluctuation of the torque transmitted between the input shaft 26 and the output shaft 30.

In the case of this embodiment, the pressing force and the pressing direction by the solenoid 76 are determined by the input shaft 26 and the output shaft 30.
It can be adjusted independently of the fluctuation of the torque transmitted between. Therefore, by controlling the pressing force or pressing direction by the solenoid 76, when the torque transmitted between the input shaft 26 and the output shaft 30 reaches a certain magnitude, the outer circumference of the inner ring 33b is controlled. Sliding may occur between the surface 34 and the outer peripheral surface of each of the transmission rollers 40, or the contact between these two peripheral surfaces may be cut off. As a result, it is possible to prevent the constituent members from being damaged, thereby ensuring the safety of the friction roller type transmission of the present invention. Also, the plunger 7
7, a permanent magnet magnetized in the axial direction is used, and the direction of energization to the coil 84 is controlled.
When the force is attracted to the coil 84 and a force is applied to the input shaft 26 in the right direction in FIG. 4, the connection of the power transmission unit 62 can be disconnected. Of course, at the time of power transmission, the plunger 77 is urged away from the coil 84. Such an operation and effect can be obtained similarly when a hydraulic pressing device is used as the pressing means. Other configurations and operations are the same as those of the above-described fourth example. In addition, the solenoid 76,
Alternatively, the friction roller type transmission of the present invention can be configured by combining the hydraulic pressing device and the planetary roller type power transmission portion 62a shown in FIG. 5 described above. Regardless of the structure employed, ON and OFF of power transmission can be controlled, so that, for example, a starting clutch can also be used as a transmission for an automobile having a small output.

Although not shown, the friction roller type transmission according to the present invention can be used not only as a speed reducer but also as a speed increaser. That is, in the above-described fourth to sixth examples, the input shaft 26 and the output shaft 30 can be exchanged and used as it is as a speed-increasing gear. Further, the pressing means such as the loading cam device 42b and the solenoid 76 may be provided on the input shaft side or on the output shaft side. However, in order to more effectively prevent the contact portion between the outer peripheral surface of the transmission roller 40 and the outer peripheral surface 34 of the inner race 33b and the inner peripheral surface 36 of the outer race 35b from slipping, and to obtain good transmission efficiency immediately after the start of operation. Preferably, the pressing means is provided on the input shaft side.

In the first to sixth examples described above, each pressing means can be provided on both the input shaft 26 side and the output shaft 30 side. If both are provided, good transmission efficiency can be obtained immediately after the start of operation even when the same type of friction roller type transmission is used as a speed reducer or when used as a speed increaser. When a loading cam device is employed as the pressing means, the cam surface constituting the loading cam device may be provided on at least one of a pair of surfaces that sandwich a plurality of pressing rollers. However, the torque to be transmitted by the loading cam device is large, and this torque is applied only to the frictional force acting between the rolling surface of each pressing roller and the flat surface formed on the other surface of the pair of surfaces. If it is difficult to transmit by cam,
Form on both sides of the pair.

Further, when the cam surface constituting the loading cam device is provided on only one surface, the shape of the cam surface is devised so that the loading cam device can be rotated only in a predetermined direction. A function of a one-way clutch that generates thrust can be added. That is, in this case, as shown in FIG. 7, of the cam surface 78 which is uneven in the circumferential direction, each pressing roller 4
The cross section of the concave portion 80, which is a portion for sandwiching the concave portion 6, in the circumferential direction (vertical direction in FIG. 7) of the concave portion 80 is changed from one side (the upper side in FIG. 7) to the other side (the upper side in FIG. 7). It is formed so as to be recessed inside the cam plate 81 toward the lower side. In the case of the loading cam device configured as described above, when transmitting the rotational force in a predetermined direction, as shown in FIG. 7A, each of the pressing rollers 46 forms one side of each of the concave portions 80 in the circumferential direction. Rides on the inclined surface 82. Thus, the rolling surface of each of the pressing rollers 46, the flat surface 79 and the cam surface 78 are formed.
The contact pressure with the contact surface increases, and the rotational force in the predetermined direction is transmitted based on frictional engagement between the surfaces. On the other hand, when transmitting the rotational force in the direction opposite to the predetermined direction, as shown in FIG. 7B, each of the pressing rollers 46 is moved to the other circumferential side of each of the concave portions 80. It moves to the existing back part 83. Thereby, the contact pressure between the rolling surface of each pressing roller 46 and the flat surface 79 and the cam surface 78 is reduced, or the rolling surface of each pressing roller 46 and the flat surface 79 are separated. I do. As a result, the frictional engagement between the rolling surface of each of the pressing rollers 46 and the flat surface 79 and the cam surface 78 is released, and it becomes impossible to transmit the rotational force in the direction opposite to the predetermined direction.

[0040]

Since the present invention is constructed and operates as described above, it is possible to realize a small-sized friction roller type transmission having good transmission efficiency and contribute to miniaturization and improvement of performance of various mechanical devices. .

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a half sectional view showing the second example.

FIG. 3 is a half sectional view showing the third example.

FIG. 4 is a half sectional view showing the fourth example.

FIG. 5 is a half sectional view showing the fifth example.

FIG. 6 is a half sectional view showing the sixth example.

FIG. 7 is a partial schematic cross-sectional view showing another example of a cam surface formed on a cam plate.

FIG. 8 is a cross-sectional view of a conventionally known electric motor with a planetary roller type reduction gear.

FIG. 9 is a sectional view taken along line AA of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 2 Motor case 3 Case main body 4 Lid 5 Rotation drive shaft 6 Stator 7 Rotor 8 Planetary roller type reduction gear 9 Center roller 10 1st cylindrical surface 11 Outer ring 12 Cylindrical wall part 13 2nd cylindrical surface 14 Annular space DESCRIPTION OF SYMBOLS 15 Axis 16 Planetary roller 17 Radial needle bearing 18 Third cylindrical surface 19 Connection plate 20 Output shaft 21 Fixing bolt 22 Connection bolt 23 Cover 24 Cylindrical part 25 Ball bearing 26, 26a Input shaft 27 Frame 28 Housing 29 Radial needle bearing 30, Reference Signs List 30a Output shaft 31 Cylindrical part 32 Ball bearing 33, 33a, 33b Inner ring 34 Outer surface 35, 35a, 35b Outer ring 36 Inner surface 37 Mounting part 65 38 Axis 39 Annular space 40 Transmission roller 41 Support hole 42, 42a, 42b Loading cam Device 43, 43a, 43b Cam plate 4, 44a, 44b Cam surface 45 Large diameter end surface 46 Pressing roller 47 Small diameter side end surface 48, 48a Elastic member 49 Cover 50 Support bracket 51, 51a Holder 52 Large diameter side end surface 54, 54a Radial needle bearing 55, 56 Flange 57 , 57a Stopper 58 First housing element 59, 59a Second housing element 60 Radial needle bearing 61 Space 62, 62a Power transmission section 63 Nut 64 Step surface 65 Mounting section 66 Ring section 67 Cylindrical section 68 Thrust needle bearing 69 yen Plate 70 Flange 71 Flat surface 72 Third housing element 73 Thrust needle bearing 74 Radial needle bearing 75 Flange 76 Solenoid 77 Plunger 78 Coil 79 Flat surface 80 Depression 81 Cam plate 82 Inclined surface 83 Back 84 coil

Claims (2)

[Claims] A first rotating shaft, a second rotating shaft arranged concentrically with the first rotating shaft and rotating relative to the first rotating shaft, and a first rotating shaft. An inner ring having a conical convex surface on the outer peripheral surface rotatably supported on the outer peripheral surface together with the first rotating shaft, and an outer ring disposed concentrically with the inner ring around the inner ring and having a conical concave inner peripheral surface. And a plurality of pivots inserted between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring; and rotatably supported around each of the pivots, each outer peripheral surface being the inner peripheral surface of the outer ring. A plurality of tapered roller-shaped transmission rollers abutted on the outer peripheral surface of the inner ring, a first support member for connecting and supporting the base ends of the plurality of pivots, and the outer ring A second support member for supporting the first and second support members, one of the first and second support members And a coupling member for coupling the second rotating shaft, and at the time of power transmission between the first rotating shaft and the second rotating shaft, at least one of the inner ring and the outer ring is A friction roller type transmission comprising: pressing means for pressing in a direction of an axis toward a plurality of transmission rollers; and fixing the other of the first and second support members. 2. The apparatus according to claim 1, wherein at least one of the first rotating shaft and the second rotating shaft is freely displaceable in the axial direction, and the pressing means is a space for installing the inner ring, the outer ring, and the plurality of transmission rollers. Of the inner ring and the outer ring by axially pressing a rotation axis of the first rotation axis and the second rotation axis, the rotation axis being freely displaceable in the axial direction. 2. The friction roller type transmission according to claim 1, wherein at least one of said transmissions is axially pressed toward said plurality of transmission rollers.