JP2013108600A - Friction roller type speed reducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure, with which repair and replacement work can be easily performed when an annular roller is damaged, in a friction roller type speed reducer of a type in which the annular roller rotates.SOLUTION: The annular roller 5b and an output shaft 3b are connected with a connection bracket 30 to enable synchronized rotation. A holding tube part 32 of the connection bracket 30 is disposed around the annular roller 5b. The holding tube part 32 and the annular roller 5b are coupled enabling torque transmission, by engaging a recessed part 35 formed on an inner circumferential surface of the holding tube part 32 and a protrusion 37 formed on the outer circumferential surface of the annular roller 5b. Further, a retaining ring 43 prevents the annular roller 5b from exiting from the holding tube part 32.

Description

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

[Description of prior art]
In order to improve the convenience of electric vehicles that have begun to spread in recent years, it is important to improve the efficiency of the electric motor in order to increase the travelable distance per charge. In order to improve this efficiency, it is effective to use a small electric motor that rotates at high speed, and to reduce the rotation of the output shaft of this electric motor before transmitting it to the drive wheels. Of the speed reducers used in this case, at least the first stage speed reducer directly connected to the output shaft of the electric motor has a very high operating speed, so friction and noise during operation can be reduced. It is conceivable to use a roller speed reducer. As a friction roller type speed reducer that can be used in such a case, for example, those described in Patent Documents 1 to 3 are known. Of these, the conventional structure described in Patent Document 3 will be described with reference to FIGS.

The friction roller speed reducer 1 includes an input shaft 2, an output shaft 3, a sun roller 4, an annular roller 5, a plurality of planetary rollers 6 and 6, each of which is an intermediate roller, a loading cam device 7, Is provided.
Among these, the sun roller 4 is concentric with each other with a pair of sun roller elements 8a and 8b divided in the axial direction around the input shaft 2 and with a gap interposed between the tip surfaces of each other. Of these, the sun roller element 8a is arranged so as to be rotatable relative to the input shaft 2. The outer peripheral surfaces of the two sun roller elements 8a and 8b are inclined surfaces that are inclined in a direction in which the outer diameter becomes smaller toward the respective front end surfaces, and these inclined surfaces serve as rolling contact surfaces. Therefore, the outer diameter of this rolling contact surface is small at the axially intermediate portion and becomes larger toward both ends.

The annular roller 5 has a circular shape as a whole, and is supported and fixed to a fixed portion such as a housing (not shown) in a state of being arranged concentrically with the sun roller 4 around the sun roller 4. . The inner peripheral surface of the annular roller 5 is a rolling contact surface inclined in a direction in which the inner diameter increases toward the axial center.
The planetary rollers 6 and 6 are disposed at a plurality of locations in the circumferential direction of the annular space 9 between the outer peripheral surface of the sun roller 4 and the inner peripheral surface of the annular roller 5. The planetary rollers 6, 6 are rotatable around planetary shafts 10, 10, which are rotation shafts, which are arranged in parallel with the input shaft 2 and the output shaft 3, respectively, via radial needle bearings. I support it. The base end portions of the planetary shafts 10 and 10 are supported and fixed to a carrier 11 that is a support frame and is fixedly coupled to the base end portion of the output shaft 3. The outer peripheral surfaces of the planetary rollers 6, 6 are convex curved surfaces having a partial arc shape on the generatrix, and are in rolling contact with the outer peripheral surface of the sun roller 4 and the inner peripheral surface of the annular roller 5, respectively.

  Further, the loading cam device 7 is provided between one sun roller element 8 a and the input shaft 2. For this purpose, a support ring 13 is locked to the intermediate portion of the input shaft 2 by a retaining ring 12, and the support ring 13 and the one sun roller element 8a are arranged in this order from the support ring 13 side. A disc spring 14, a cam plate 15, and a plurality of balls 16, 16 are provided. Then, the driven cam surfaces 17 and 17 and the driving cam surface 18 are respectively provided at a plurality of circumferential positions on the base end surface of the one sun roller element 8a and the one side surface of the cam plate 15 facing each other. , 18 are provided. Each of the cam surfaces 17 and 18 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 7, when the input shaft 2 is stopped, the balls 16, 16 are deepest on the cam surfaces 17, 18 as shown in FIG. Located in the part. In this state, the one sun roller element 8a is pressed toward the other sun roller element 8b by the elasticity of the disc spring 14. On the other hand, when the input shaft 2 rotates, the balls 16 and 16 move to shallow portions of the cam surfaces 17 and 18 as shown in FIG. Then, the distance between the one sun roller element 8a and the cam plate 15 is increased, and the one sun roller element 8a is pressed toward the other sun roller element 8b. As a result, the one sun roller element 8a is generated by the elasticity of the disc spring 14 and the balls 16, 16 riding on the cam surfaces 17, 18 toward the other sun roller element 8b. 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 1 as described above, the distance between the two sun roller elements 8a and 8b is reduced by the axial thrust generated by the loading cam device 7. And the surface pressure of the rolling contact portion between the outer peripheral surface of the sun roller 4 constituted by both the sun roller elements 8a and 8b and the outer peripheral surface of the planetary rollers 6 and 6 increases. As the surface pressure increases, the planetary rollers 6 and 6 are pushed outward in the radial direction of the sun roller 4 and the annular roller 5. Then, the surface pressure of the rolling contact portion between the inner peripheral surface of the annular roller 5 and the outer peripheral surfaces of the planetary rollers 6 and 6 also increases. As a result, the surface pressures of the plurality of rolling contact portions, which are provided between the input shaft 2 and the output shaft 3 and are to be used for power transmission, each of which is a traction portion, are determined by It rises according to the magnitude of the torque to be transmitted between.

  When the input shaft 2 is rotated in this state, the rotation is transmitted from the sun roller 4 to the planetary rollers 6, 6, and the planetary rollers 6, 6 are rotating around the sun roller 4. Revolve. The revolving motion of these planetary rollers 6 and 6 can be taken out by the output shaft 3 through the carrier 11. The surface pressure of each of the traction portions is appropriate according to the magnitude of torque to be transmitted between the two shafts 2 and 3, and excessive slip occurs in each of the traction portions, or these It is possible to prevent the rolling resistance from increasing due to excessive surface pressure of each traction section.

[Description of Prior Invention]
The above-described conventional structure is a planetary roller type friction roller type speed reducer that takes out the revolving motion of the planetary roller through the carrier. However, according to the structure in which the rotation of the annular roller is taken out to the output shaft, the carrier is not rotated. It will end. The fact that it is not necessary to rotate the carrier is to increase the strength and rigidity of each part and to ensure the durability of the friction roller type reducer, and in addition to each rolling contact part between the peripheral surfaces of each roller There are advantages such as easy supply of traction oil to the traction section and the like. As such a friction roller type speed reducer that rotates an annular roller, there is an invention according to Japanese Patent Application No. 2011-57869. The friction roller type speed reducer according to the present invention will be described with reference to FIGS.

  The friction roller type speed reducer 1a according to the present invention rotationally drives the sun roller 4a by the input shaft 2a, and transmits the rotation of the sun roller 4a to the annular roller 5a through a plurality of intermediate rollers 19, 19. The rotation of the annular roller 5a is taken out from the output shaft 3a. Each of the intermediate rollers 19, 19 rotates only around the rotation shafts 20, 20 provided at the center thereof, and does not revolve around the sun roller 4 a. This sun roller 4a is formed by concentrically combining a pair of sun roller elements 8c, 8c having the same shape, and a pair of loading cams at a position sandwiching both the sun roller elements 8c, 8c from both sides in the axial direction. Devices 7a and 7a are installed. Each of these parts is housed in a stepped cylindrical housing 21 in which the diameter of the intermediate part in the axial direction is large and the diameters at both ends are small.

  The base half of the input shaft 2a (the right half of FIG. 24) is placed inside the input side small diameter cylindrical portion 22 of the housing 21 and a multi-row ball bearing unit 23, and the output shaft 3a is also the output side small diameter cylindrical portion. Each is supported rotatably by a double row ball bearing unit 25 inside 24. A labyrinth seal 26 is provided between a pair of ball bearings constituting the double row ball bearing unit 25, and foreign matter enters the housing 21 through the installation portion of the output shaft 3a located on the outer space side. It is preventing. The base end portion of the output shaft 3a is connected to the annular roller 5a by a connecting portion 27 having an L-shaped cross section.

  The two sun roller elements 8c, 8c are concentric with the input shaft 2a around the front half of the input shaft 2a so as to be able to rotate relative to the input shaft 2a, and have their front end surfaces (opposing each other). Are arranged with a gap between them. The pair of cam plates 15a and 15a constituting the both loading cam devices 7a and 7a are positioned at two positions of the intermediate portion and the tip portion of the input shaft 2a, and the sun roller elements 8c and 8c are pivoted. It is fitted and fixed at positions sandwiched from both sides in the direction so as to rotate in synchronization with the input shaft 2a. Then, the driven cam surfaces 17 and 17 are driven at a plurality of positions in the circumferential direction between the base end surfaces of the sun roller elements 8c and 8c and the one side surfaces of the cam plates 15a and 15a, which face each other. Side cam surfaces 18 and 18 are provided, and balls 16 and 16 are sandwiched between the cam surfaces 17 and 18 to constitute both loading cam devices 7a and 7a. Each of the cam surfaces 17 and 18 has a depth in the axial direction that gradually changes in the circumferential direction, and is deepest at the central portion in the circumferential direction, and also becomes shallower toward both ends.

  In a state where torque is not input to the input shaft 2a, as shown in FIG. 25A, the balls 16, 16 constituting the loading cam devices 7a, 7a are connected to the cam surfaces 17, It exists on the bottom of 18 or the side close to the bottom. From this state, when torque is input to the input shaft 2a (the friction roller type speed reducer 1a is activated), the engagement between the balls 16 and 16 and the cam surfaces 17 and 18 As shown in FIG. 25B, the axial thicknesses of both loading cam devices 7a and 7a increase. The sun roller elements 8c, 8c bite into the intermediate rollers 19, 19 with respect to the radial direction of the friction roller type speed reducer 1a, and remove the intermediate rollers 19, 19 with respect to the radial direction. Push towards. As a result, the surface pressure of each of the traction portions increases, and power can be transmitted from the sun roller 4a to the annular roller 5a without causing excessive slippage in the traction portions. A direction in which a spring is provided between the sun roller element 8c constituting the loading cam devices 7a, 7a and the cam plate 15a, and the members 8c, 15a are relatively rotated with respect to the rotation direction. Of elasticity. Based on this elasticity, the balls 16, 16 tend to run on the shallow sides of the cam surfaces 17, 18, and a certain amount of thrust is applied to the loading cam devices 7a, 7a even when power is not transmitted. Is generated (preload is applied).

  At the time of operation of the friction roller type speed reducer 1a, each of the intermediate rollers 19 and 19 rotates around the respective rotation shafts 20 and 20, and at the same time, the radial direction of the friction roller type speed reducer 1a is accompanied by a change in transmission torque. It is displaced to. In the case of the structure of the previous invention in order to smoothly perform the rotation and radial displacement of the intermediate rollers 19 and 19, the rotation shafts 20 that are the rotation centers of the intermediate rollers 19 and 19. , 20 with respect to the support frame 28 that is supported and fixed inside the housing 21 so as to be capable of displacement in the radial direction of the sun roller 4a and the annular roller 5a.

  When the input shaft 2a is rotationally driven during the operation of the friction roller type speed reducer 1a according to the previous invention configured as described above, both the cam plates 15a, 15a fitted on the input shaft 2a rotate, The sun roller elements 8c, 8c rotate at the same speed in the same direction as the input shaft 2a while being pressed toward each other based on the engagement between the balls 16, 16 and the cam surfaces 17, 18. . Then, the rotation of the sun roller 4a constituted by the both sun roller elements 8c and 8c is transmitted to the annular roller 5a through the intermediate rollers 19 and 19, and is taken out from the output shaft 3a. In order to circulate traction oil in the housing 21 during operation of the friction roller type speed reducer 1a, traction oil is provided at the rolling contact portion (traction portion) between the peripheral surfaces of the rollers 4a, 19, 5a. The thin film exists. Further, the surface pressure of each of these traction portions is appropriately adjusted by the both loading cam devices 7a and 7a. Therefore, power transmission can be performed without causing excessive slippage in each traction section, regardless of changes in the operating state of the friction roller type speed reducer 1a.

  During the operation of the friction roller type speed reducers 1 and 1a according to the above-described conventional or the above-described prior invention, the inner surfaces of the annular rollers 5 and 5a are connected to the sun rollers 4 and 7 from the loading cam devices 7 and 7a. A large radial load is applied by the radial force applied to the planetary rollers 6 and 6 or the intermediate rollers 19 and 19 via 4a. Further, a portion of the annular rollers 5 and 5a to which this radial load is applied moves in the circumferential direction along with the revolution of the planetary rollers 6 and 6 or the rotation of the annular roller 5a. As described above, a situation in which a large radial load is applied to a part of the circumferential direction and the applied position is constantly moved in the circumferential direction is a severe situation from the viewpoint of ensuring the durability of the annular rollers 5 and 5a.

  In the case of the planetary roller type friction roller speed reducer 1 shown in FIG. 21, since the annular roller 5 is fixed, the annular roller 5 is easily reinforced by a housing or the like, which is advantageous from the viewpoint of ensuring durability. is there. Further, since the shape of the annular roller 5 is simple, the cost can be reduced when the damaged annular roller 5 is repaired or replaced. On the other hand, in the case of the friction roller type speed reducer 1a according to the previous invention shown in FIG. 24, the annular roller 5a rotates, so that it cannot be reinforced by the housing 21, which is disadvantageous from the viewpoint of ensuring durability. is there. Further, since the annular roller 5a, the connecting portion 27, and the output shaft 3a are integrated, when the annular roller 5a is damaged, the cost required for repair and replacement increases.

JP 59-187154 A JP-A-61-136053 JP 2004-116670 A

  In view of the above-described circumstances, the present invention is a friction roller type speed reducer of a type in which an annular roller rotates, and realizes a structure that can be easily repaired and replaced when the annular roller is damaged. Invented accordingly.

The friction roller type speed reducer of the present invention includes an input shaft, an output shaft, a sun roller, an annular roller, a plurality of intermediate rollers, and a loading cam device.
Of these, the sun rollers are concentric to each other with a pair of sun roller elements divided in the axial direction around the input shaft, with a gap between the tip surfaces of the elements. It is arranged so that it can rotate relative to the shaft. The outer peripheral surfaces of the two sun roller elements are inclined surfaces that are inclined in a direction in which the outer diameter decreases toward the respective tip surfaces, and both the inclined surfaces serve as rolling contact surfaces.
The annular roller is disposed around the sun roller concentrically with the sun roller, and has an inner peripheral surface which is a rolling contact surface and is concentrically coupled to the output shaft via a connecting bracket. Thus, it can be rotated together with this output shaft.
Each of the intermediate rollers has a rotation shaft arranged in parallel with the input shaft at a plurality of locations in the circumferential direction of the annular space between the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller. Each outer peripheral surface is in rolling contact with the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller while being rotatably supported around the center.
The loading cam device is provided between the movable sun roller element, which is at least one of the two sun roller elements, and the input shaft. The sun roller element is rotated while being pressed in the axial direction toward the other sun roller element.
The intermediate rollers rotate about the rotation shafts while being pressed against the inner peripheral surface of the annular roller based on a pressing force generated by the loading cam device as the input shaft rotates.
Further, the connection bracket includes a base portion that is connected to an end portion of the output shaft so as to be able to transmit torque, a holding cylinder portion disposed around the annular roller, and a connection that connects the base portion and the holding cylinder portion. A part. The annular roller and the coupling bracket transmit torque by engaging protrusions formed at a plurality of circumferential positions of the annular roller and recesses formed at a plurality of circumferential positions of the holding cylinder portion. Is possible to combine.

When the friction roller type speed reducer according to the present invention as described above is implemented, more specifically, for example, as in the invention described in claim 2, the annular roller and the connecting bracket are connected to the annular roller. The protrusions formed at a plurality of locations in the circumferential direction of the outer peripheral surface are engaged with the recesses formed in a plurality of locations in the circumferential direction of the inner peripheral surface of the holding cylinder portion and continuously recessed in the axial direction in a radially recessed state. It is possible to couple torque transmission. The projections are prevented from coming out of the recesses by a retaining ring locked to a portion closer to the opening than the annular roller in the axial direction in the inner peripheral surface of the holding cylinder portion.
When the invention described in claim 2 is implemented, preferably, as in the invention described in claim 3, the protrusions are notched into the tops of the notches so as to be recessed radially inward. The shape is provided.
Further, when the invention described in claim 3 is carried out, more preferably, as in the invention described in claim 4, the shape of each of the protrusions viewed from the axial direction is set to both sides in the circumferential direction. The side surface and the outer peripheral surface of the annular roller are smoothly continuous by a partial arc so that the width dimension in the circumferential direction increases in the radially inner direction. And the said notch part formed in the top part of each said protrusion is each made into partial arc shape.

  Alternatively, as another specific structure when implementing the friction roller type speed reducer of the present invention, for example, as in the invention described in claim 5, the annular roller and the connecting bracket are arranged in the axial direction of the annular roller. Torque transmission is possible by engaging protrusions formed at multiple locations in the circumferential direction of the side surface and recesses formed in the axially recessed state at multiple locations in the circumferential direction inside the holding cylinder. Combine. The projections are prevented from coming out of the recesses by a retaining ring locked to a portion closer to the opening than the annular roller in the axial direction in the inner peripheral surface of the holding cylinder portion.

According to the friction roller type speed reducer of the present invention configured as described above, repair and replacement work can be easily performed when the annular roller is damaged.
That is, since the connecting bracket for transmitting torque between the annular roller and the output shaft is separated from the annular roller, when the annular roller is repaired or replaced, the annular roller is By separating from the connecting bracket, this repair and replacement work can be done easily and at low cost.

Sectional drawing which shows the power transmission device of the drive device for electric vehicles incorporating the friction roller type reduction gear of this invention. The a section enlarged view of FIG. The figure seen from the right side of FIG. The perspective view shown in the state which took out the friction roller type reduction gear, abbreviate | omitted the sun roller and the annular roller, and was seen from the upper right of FIG. The orthographic projection shown in the state similarly seen from the right side of FIG. The orthographic view seen from the left of FIG. Bb sectional drawing of FIG. The perspective view which shows the state which assembled the connection bracket, the annular roller, and the retaining ring. The perspective view shown in the state before assembling similarly. The c section enlarged view of FIG. Dd sectional drawing of FIG. The schematic diagram which shows the cross-sectional shape of an annular roller with the part (A) which formed the protrusion, and the part (B) which removed from the protrusion. The perspective view (A) and end view (B) which show the 1st example of the shape of an annular roller. The figure similar to FIG. 13 which shows the said 2nd example. The figure similar to FIG. 13 which shows the 3rd example. The figure similar to FIG. 13 which shows the same 4th example. The figure similar to FIG. 13 which shows the said 5th example. The end view which shows another 3 examples of the shape of the processus | protrusion of an annular roller outer peripheral surface. The perspective view which shows the 6th example of the shape of an annular roller. Sectional drawing similar to FIG. 11 which shows three examples of the assembly state with respect to the connection bracket of the annular roller of this 6th example. Sectional drawing which shows an example of the friction roller type reduction gear conventionally known. FIG. 22 is a cross-sectional view taken along the line ee of FIG. The schematic diagram equivalent to the ff cross section of FIG. 22 which each shows the state (B) which has generate | occur | produced similarly to the state (A) in which the loading cam apparatus is not generating thrust. Sectional drawing of the friction roller type reduction gear which concerns on a prior invention. The schematic diagram which shows the condition where an intermediate | middle roller displaces based on the effect | action of a loading cam apparatus at the time of non-transmission of a torque (A) and transmission (B).

[First example of embodiment]
FIGS. 1-13 has shown the 1st example of embodiment of this invention corresponding to Claim 1,2. The friction roller type speed reducer 1b of this example is housed in a speed reducer case such as the housing 21 shown in FIG. Then, the sun roller 4b is rotationally driven by an input shaft 2b that is provided outside the speed reducer case and is coupled to a drive shaft of an electric motor (not shown), and the rotation of the sun roller 4b is caused by rotating a plurality of intermediate rollers 19a and 19a. The rotation of the annular roller 5b is taken out through the output shaft 3b. In order to install the output shaft 3b, a bearing case 29 is oil-tightly fixed to one end side wall portion of the speed reducer case. The output shaft 3b is rotatably supported by the output side rolling bearing unit 45 and the output side sealing unit 46 on the inner diameter side of the bearing case 29 while maintaining oil tightness. The output shaft 3b and the annular roller 5b are coupled to each other by a connection bracket 30 in a state of being arranged concentrically with each other.

  The connection bracket 30 includes a base portion 31, a holding cylinder portion 32, and a connection portion 33. Of these, the base portion 31 is formed in a cylindrical shape, and is fitted and fixed to the base end portion of the output shaft 3b. Of the inner peripheral surface of the base 31, the front half (left half in FIG. 1) is a cylindrical surface and the latter half (right half in FIG. 1) is the fitting direction with respect to the base end of the output shaft 3b. It is a female spline part. The root diameter (maximum inner diameter) of the female spline portion is equal to or smaller than the inner diameter of the cylindrical surface portion. Such a base 31 fits the cylindrical surface portion and the cylindrical surface portion on the outer peripheral surface side of the output shaft 3b with an interference fit, and also includes the female spline portion and the male spline portion on the outer peripheral surface side of the output shaft 3b. Are combined to enable torque transmission. Further, in this state, the flange 34 formed on the outer peripheral surface of the output shaft 3b is brought into contact with the axial end surface of the base portion 31, so that the output shaft 3b and the connection bracket 30 including the base portion 31 are brought into contact with each other. The positioning in the axial direction is intended.

  Further, the holding cylinder portion 32 is formed into a substantially cylindrical shape by subjecting a metal material such as carbon steel, which can ensure the required strength and rigidity, to appropriate processing such as cutting and extrusion. doing. The holding cylinder portion 32 has a plurality of circumferential locations (six locations in the example shown in the figure) directed outward in the radial direction and projecting into a substantially “concave” shape, thereby forming recesses 35, 35 on the inner circumferential surface of the portion. Is forming. Of the inner peripheral surface of the holding cylinder portion 32, the portions excluding these concave portions 35, 35 are positioned on a single cylindrical surface.

  Further, the connecting portion 33 is formed integrally with the base portion 31 and has a stepped partial conical cylindrical shape as a whole, and the base end portion (left end portion in FIG. 1) is continued to the base portion 31. The holding cylinder portion 32 is coupled and fixed to the distal end portion (the right end portion in FIGS. 1 and 2). The holding cylinder part 32 and the connecting part 33 (and the base part 31) may be configured integrally, but in the case of the structure of this example, the connecting part 33 and the holding cylinder part 32 are The separate parts are connected and fixed by fitting them with an interference fit afterwards. For this reason, in the case of this example, a support cylinder part 36 for externally fixing and fixing the base end part (the left end part in FIGS. 1 and 2) of the holding cylinder part 32 is formed at the distal end part of the connecting part 33. doing. The holding cylinder part 32 and the connecting part 33 have a large tightening allowance by shrink fitting or cold fitting or the like on the support cylinder part 36 at the base end part (left end part in FIGS. 1 and 2) of the holding cylinder part 32. They are concentrically coupled and fixed to each other so that torque can be transmitted by external fitting or by welding.

  The annular roller 5b is fitted in the intermediate portion of the holding cylinder portion 32 so as to be able to transmit torque to and from the holding cylinder portion 32. The annular roller 5b is made of a metal material that can ensure sufficient strength and rigidity, such as bearing steel, high speed steel, high carbon steel, etc. Protrusions 37 and 37 are formed at a plurality of locations, respectively. Each of the protrusions 37 and 37 is connected to all or a part of the recesses 35 and 35 on the inner peripheral surface of the holding cylinder portion 32 without rattling in the circumferential direction (rotation transmission direction). Match. In the example shown in the figure, the projections 37 are provided at three positions on the outer circumferential surface of the annular roller 5b at equal intervals in the circumferential direction, and the projections 37 are connected to one of the recesses 35, 35. It engages with the recesses 35, 35.

  Further, in the case of this example, the portion of the inner peripheral surface of the holding cylinder portion 32 that is removed from the concave portions 35 and 35 in the circumferential direction and the outer peripheral surface of the annular roller 5b are stepped in the axial direction. It has a shape. Specifically, an inner peripheral surface side stepped portion 38 is formed at an axially intermediate portion of the inner peripheral surface of the holding cylinder portion 32, and the inner diameter of the holding cylinder portion 32 is defined as the boundary between the inner peripheral surface side stepped portion 38. As shown in FIG. 8, the distal end side (the right side in FIGS. 8 to 10) is larger than the proximal end side (the left side in FIGS. 8 to 10). In accordance with this, an outer peripheral surface side stepped portion 39 is formed at an axially intermediate portion of the outer peripheral surface of the annular roller 5b, and the outer diameter of the annular roller 5b is set at the front end with the outer peripheral surface side stepped portion 39 as a boundary. The side is larger than the base end side. Each of the protrusions 37 is formed on the tip end portion of the outer peripheral surface of the annular roller 5b where the outer diameter is increased. In the case of this example, the projections 37, 37 are parallel to each other on both sides in the circumferential direction, and are provided with partial arc-shaped notches 40 that are recessed inward in the radial direction at the tops.

  Further, a locking groove 41 is formed in a portion of the inner peripheral surface of the holding cylinder portion 32 that is closer to the distal end side than the inner peripheral surface side stepped portion 38. The locking groove 41 is formed over substantially the entire circumference except for the point where the recesses 35 are interrupted. The distance from the front end surface 42 of the support cylinder part 36 to the base end side edge of the locking groove 41 is made to coincide with the axial thickness of the annular roller 5b.

  The annular roller 5b and the holding cylinder portion 32, each having the above-described configuration, are brought close to each other in the axial direction, and the concave portions 35, 35 and the projections 37, 37 are engaged with each other. , Combining torque transmission between each other. Further, by locking the retaining ring 43 in the locking concave groove 41, the annular roller 5b is prevented from moving in the direction of coming out of the holding cylinder portion 32. The retaining ring 43 is formed in a ring shape with a metal plate having elasticity and sufficient strength and rigidity, such as a spring steel plate, and has locking holes 44 and 44 at both ends in the circumferential direction. Such a retaining ring 43 is inserted into the holding cylinder portion 32 in a state where the distal end portion of the tool is locked in the locking holes 44, 44 and the outer diameter is reduced, The tool is removed while being positioned on the inner diameter side. Then, a portion closer to the outer diameter of the retaining ring 43 is locked in the locking groove 41. In this state, the annular roller 5b and the holding cylinder portion 32 are combined in a state where torque transmission is possible and separation in the axial direction is also prevented. When the annular roller 5b and the holding cylinder part 32 are separated from each other, the outer diameter of the retaining ring 43 is reduced by the tool, and the retaining ring 43 is extracted from the holding cylinder part 32, and then the annular roller 5b. Is extracted from the holding cylinder portion 32.

  The input shaft 2b is rotated in an oil tight state by an input side rolling bearing unit 47 and an input side sealing unit 48 inside the other end side wall (not shown) of the speed reducer case. Supports freely. And the said sun roller 4b is provided in the front-end | tip part of the said input shaft 2b, and this sun roller 4b is rotated by this input shaft 2b. This sun roller 4b is composed of a pair of sun roller elements 8d and 8d having symmetrical shapes as in the case of the prior invention structure shown in FIGS. 24 to 25, and the base half of the input shaft 2b. It arrange | positions around (the left half part of FIG. 1). Further, loading cam devices 7b and 7b are provided between the sun roller elements 8d and 8d and the input shaft 2b, respectively, and these sun roller elements 8d and 8d are pressed in a direction approaching each other. The elements 8d and 8d are driven to rotate together with the input shaft 2b. The cam plates 15b and 15b constituting the both loading cam devices 7b and 7b are fitted and fixed to the input shaft 2b by an interference fit, and rotate together with the input shaft 2b. Further, the opposite side surfaces of the cam plates 15b and 15b are respectively pushed into a flange portion 49 formed at the intermediate portion of the input shaft 2b or a loading nut 50 screwed and fixed to the base end portion of the input shaft 2b. I guess. The loading cam devices 7b and 7b are similar to the loading cam device 7 having the conventional structure shown in FIG. 21 described above, in addition to a plurality of driven-side and driving-side cam surfaces and balls. For application, a coil spring is provided for pressing both the cam plates 15b, 15b and the two sun roller elements 8d, 8d in the relative rotational direction. The structure of this part is not related to the gist of the present invention, and another structure can be adopted.

  Each of the intermediate rollers 19a and 19a supports the support frame 28a supported and fixed in the reduction gear case so as to be able to rotate and slightly displace in the radial direction of the support frame 28a. The reason why this radial displacement is possible is that the sun roller elements 8d and 8d approach each other due to the action of the loading cam devices 7b and 7b, and the intermediate rollers 19a and 19a are located radially outside the support frame 28a. This is because the displacement of each of the intermediate rollers 19a, 19a is allowed smoothly when pressed in the opposite direction. For this reason, the structure for enabling the displacement in the radial direction is, for example, in the middle part of the swing frames 51, 51 pivotally supporting the respective base end parts with respect to the support frame 28a. A structure in which the intermediate rollers 19a and 19a are rotatably supported by ball bearings 52 and 52 can be employed. Alternatively, a structure may be employed in which the outer rings of the ball bearings 52, 52 provided at both ends of the intermediate rollers 19a, 19a are loosely fitted inside the long holes in the radial direction formed in the support frame 28a. it can. In any case, the structure that enables the radial displacement is not related to the gist of the present invention, and a detailed description thereof will be omitted.

  Also, from the plural circumferentially equidistantly spaced locations (three locations in the illustrated example) on the one axial side surface of the annular connection portion 56 of the support frame 28a toward the installation side of the intermediate rollers 19a, 19a, Column portions 57 and 57 projecting parallel to the axial direction of the support frame 28a are provided. Further, traction oil supply passages 53 and 53 are provided inside the pillars 57 and 57, and the outer peripheral surfaces of the intermediate rollers 19a and 19a, the outer peripheral surface of the sun roller 4b, and the annular roller 5b. Traction oil can be sent to the rolling contact part (traction part) with the inner peripheral surface. The lubricant supply paths 53 and 53 need only have a structure capable of supplying the traction oil required for each traction section, and are not related to the gist of the present invention. Omitted.

  During operation of the friction roller type reduction gear 1b incorporated in a drive device for an electric vehicle or the like, the sun roller 4b is rotationally driven by the electric motor (not shown) via the input shaft 2b. The rotation of the sun roller 4b is transmitted to the annular roller 5b through the intermediate rollers 19a and 19a. The sun roller elements 8d and 8d constituting the sun roller 4b are preloaded in a direction approaching each other by the loading cam devices 7b and 7b each incorporating a preload spring. Accordingly, the surface pressure of the rolling contact portion (traction portion) between the peripheral surfaces of the rollers 4b, 19a, and 5b is ensured to some extent even when no torque is transmitted between the rollers 4b, 19a, and 5b. ing. Further, when the torque transmitted between the rollers 4b, 19a, and 5b increases, the force (thrust) that the loading cam devices 7b and 7b press the sun roller elements 8d and 8d closer to each other. Increases, and the surface pressure of each of the traction portions is further increased. Since each of the intermediate rollers 19a and 19a is supported by the support frame 28a so as to be capable of radial displacement, the outer peripheral surface of each of the intermediate rollers 19a and 19a, the outer peripheral surface of the sun roller 4b, and the annular The surface pressure of the rolling contact portion with the inner peripheral surface of the roller 5b effectively increases. As a result, power transmission from the sun roller 4b to the annular roller 5b can be performed efficiently regardless of fluctuations in torque transmitted between the rollers 4b, 19a, 5b.

  The power transmitted to the annular roller 5b in this way is the projections 37, 37 protruding from the outer peripheral surface of the annular roller 5b and the concave portions 35 formed on the inner peripheral surface of the holding cylinder portion 32. , 35 is transmitted to the holding cylinder portion 32 based on the engagement with. Further, the power transmitted to the holding cylinder portion 32 is transmitted to the output shaft 3 b via the connecting portion 33 and the base portion 31. As a result, the output shaft 3b is rotationally driven at a lower speed and with a higher torque than the input shaft 2b. In addition, when power is transmitted between the annular roller 5 b and the holding cylinder portion 32, circumferential stress is generated in the protrusions 37 and 37. Since the diameters of the installation portions of the projections 37 and 37 are large, the projections 37 and 37 are cracked without particularly increasing the size (circumferential width and axial length) of the projections 37 and 37. It is unlikely that such damage will occur. However, in order to more reliably prevent damage to the protrusions 37 and 37 while reducing the size and weight of the friction roller type speed reducer 1b, the protrusions 37 and 37 are attached to the protrusions 37 and 37 as the power is transmitted. It is preferable to suppress the generated stress to a lower level. In the case of this example, a notch 40 is formed at the center of the top of each of the protrusions 37. For this reason, these protrusions 37 and 37 are appropriately elastically deformed in the circumferential direction, and the stress generated in the protrusions 37 and 37 during torque transmission can be kept low.

  Along with the operation of the friction roller type speed reducer 1b as described above, each of the rollers 4b, 19a, 5b receives a large force directed in the radial direction based on the action of the loading cam devices 7b, 7b. Repeatedly applied, an internal stress is generated in each of the rollers 4b, 19a and 5b. In particular, since a large force directed radially outward is applied to the annular roller 5b, a tensile stress is generated. Unless the thickness of the annular roller 5b in the radial direction is considerably increased, when the friction roller type speed reducer 1b is used for a long period of time, the annular roller 5b is not damaged due to the tensile stress as described above. The possibility of occurrence cannot be denied. If the entire friction roller type speed reducer 1b is replaced when damage occurs, the repair cost of the drive device for the electric vehicle and the like increases. In addition, as in the structure of the previous invention shown in FIG. 24 described above, when the annular roller 5a, the connecting portion 27, and the output shaft 3a are integrated, there are many parts to be replaced for repair, and the parts cost is low. Not only does it increase, but also the replacement work becomes cumbersome, and even if it can be suppressed as compared with the case where the entire friction roller type speed reducer 1a is replaced, repair costs still increase.

  On the other hand, according to the structure of this example, when the annular roller 5b is damaged, it is only necessary to replace the annular roller 5b, and the replacement work can be easily performed, so that the repair cost can be kept low. . That is, as described above, the damaged annular roller 5b and the holding cylinder portion 32 reduce the outer diameter of the retaining ring 43 with a tool, and after removing the retaining ring 43 from the holding cylinder portion 32, The annular rollers 5b can be separated from each other by being extracted from the holding cylinder portion 32. Then, after the new annular roller 5b is fitted into the holding cylinder portion 32, as described above, if the retaining ring 43 is locked in the locking groove 41, the replacement operation of the annular roller 5b is completed. it can. At this time, since it is not necessary to attach or detach parts other than the annular roller 5b and the retaining ring 43, the repair / replacement work of the annular roller 5b can be performed easily and at low cost.

[Second to fifth examples of embodiment]
The second to fifth examples of the embodiment of the present invention in which the shape of the protrusion on the outer peripheral surface of the annular roller is different will be described with reference to FIGS.
First, the annular roller 5c of the second example shown in FIG. 14 corresponds to claim 4, and the shape of the projections 37a, 37a formed on the outer peripheral surface viewed from the axial direction is defined as the both side surfaces in the circumferential direction. The outer circumferential surface of the annular roller 5c is smoothly continuous with a partial arc so that the width dimension in the circumferential direction increases radially inward. Further, partial arc-shaped notches 40, 40 that are recessed inward in the radial direction are provided at the tops of the projections 37a, 37a.

  The larger the radius of curvature of the partial arc that connects the circumferential side surfaces of the projections 37a and 37a and the outer circumferential surface of the annular roller 5c, the more the stress generated with torque transmission can be reduced. However, if it is too large, it becomes difficult to engage the projections 37a and 37a with the recesses 35 and 35 (see FIGS. 1 to 3 and 8 to 10) of the holding cylinder portion 32. Considering these, when the inner diameter of the annular roller 5c is about 60 to 80 mm and the diameter of the circumscribed circle of the projections 37a and 37a is about 80 to 100 mm, the radius of curvature of the partial arc is 1.5 to 2 mm. It is preferable to regulate to about 5 mm. Of course, the value of the radius of curvature is appropriately changed according to the dimensions of the annular roller 5c, the shapes and dimensions of the recesses 35 and 35, and the like.

  Furthermore, the stress generated as the inclination angle with respect to the radial direction of both side surfaces of the projections 37a and 37a with respect to the radial direction is increased (the inclination with respect to the circumferential surface is moderated) can be reduced. It becomes difficult to engage the protrusions 37a and 37a with the concave portions 35 and 35 (see FIGS. 1 to 3 and 8 to 10) of the holding cylinder portion 32. Considering these, it is preferable to regulate the inclination angle with respect to the radial direction to about 20 to 40 degrees (the intersection angle between the top and the side surface is about 110 to 130 degrees). Of course, this angle is appropriately changed depending on the shape of each of the concave portions 35 and 35.

  In the case of the structure of this example as described above, the stress applied to each of the protrusions 37a and 37a along with torque transmission can be sufficiently reduced by devising the shape of the protrusions 37a and 37a. Note that, as in the first example of the above-described embodiment, even in a structure in which the circumferential side surfaces of the protrusions 37 and 37 are substantially orthogonal to each other in the circumferential direction, the continuous portion between these side surfaces and the outer circumferential surface of the annular roller 5b If the curved surface having a curvature radius of about 1.5 to 2 mm is smoothly continuous, the stress applied to each of the protrusions 37 and 37 can be kept low.

The annular rollers 5d to 5f of the third to fifth examples shown in FIGS. 15 to 17 are somewhat inferior to the above-described annular roller 5c of the second example in reducing the stress applied to the protrusions 37b and 37 during torque transmission. However, depending on the magnitude of the torque transmitted by the friction roller type reduction gear, it can be sufficiently put into practical use.
First, in the case of the annular roller 5d of the third example shown in FIG. 15, rectangular protrusions 37b and 37b are formed at a plurality of locations in the circumferential direction of the outer peripheral surface.
Next, in the case of the annular roller 5e of the fourth example shown in FIG. 16, the rectangular protrusions 37b and 37b formed at a plurality of locations in the circumferential direction on the outer circumferential surface are cut out at portions sandwiched from both sides in the circumferential direction. 54 and 54 are formed. In the illustrated example, the notches 54 and 54 are formed over the entire length in the thickness direction of the protrusions 37b and 37b. However, the stress can be reduced by forming the notches 54 and 54 in part. Is possible.
Further, in the case of the annular roller 5f of the fifth example shown in FIG. 17, notches 54 and 54 are formed in the portions sandwiching the projections 37 and 37 similar to those of the first example from both sides in the circumferential direction, respectively. Is. Also in the case of this example, the positions where the notches 54 and 54 are formed can be regulated in the same manner as in the case of the fourth example described above.
Furthermore, as the shape of the protrusion 37, as shown in FIGS. 18A to 18C, it is possible to adopt a shape in which both circumferential sides are parallel to each other.

[Sixth Example of Embodiment]
A sixth example of the embodiment of the present invention corresponding to claims 1 and 5 will be described with reference to FIGS. In the case of this example, projections 37c and 37c projecting in the axial direction are formed at a plurality of locations in the circumferential direction on one axial side surface of the annular roller 5g. Then, the projections 37c, 37c and the recesses 55a, 55b formed in the axially recessed state are engaged with a plurality of circumferential positions of the connection bracket 30 (FIGS. 1, 2, 8, 9). Thus, the annular roller 5g and the connecting bracket 30 are coupled so as to be able to transmit torque. Of the one side surface in the axial direction of the annular roller 5g, the radial position for forming the projections 37c, 37c is the outer end position as shown in FIG. 20A, or the central position as shown in FIG. It can be a position or an inner end position as shown in FIG. The recesses 55a and 55b are formed in accordance with the positions of the projections 37c and 37c. In order to provide these recesses 55a and 55b, a notch is formed at the front end edge of the support cylinder portion 36 (FIGS. 1 and 2) of the connecting portion 33 constituting the connecting bracket 30, and this notch is formed in each of the above-mentioned notches. It can also function as the recesses 55a and 55b. In any case, by engaging the projections 37c and 37c with the recesses 55a and 55b formed at a plurality of locations in the circumferential direction of the connection bracket 30, the annular roller 5g and the connection bracket 30 are Combine torque transmission possible. The projections 37c and 37c are prevented from coming out of the recesses 55a and 55b by the retaining ring 43 locked to the inner peripheral surface of the holding cylinder portion 32.

  The friction roller type speed reducer which is an object of the present invention is not limited to a drive system of an electric vehicle, and can be used as a power transmission device for various rotary machine devices.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Friction roller type reduction gear 2, 2a, 2b Input shaft 3, 3a, 3b Output shaft 4, 4a, 4b Sun roller 5, 5a-5g Annular roller 6 Planetary roller 7, 7a, 7b Loading cam device 8a , 8b, 8c, 8d Solar roller element 9, 9a Annular space 10 Planetary shaft 11 Carrier 12 Retaining ring 13 Support ring 14 Disc spring 15, 15a, 15b Cam plate 16 Ball 17 Drive side cam surface 18 Drive side cam surface 19, 19a Intermediate roller 20 Rotating shaft 21 Housing 22 Input side small diameter cylindrical portion 23 Multi-row ball bearing unit 24 Output side small diameter cylindrical portion 25 Double row ball bearing unit 26 Labyrinth seal 27 Connecting portion 28, 28a Support frame 29 Bearing case 30 Connecting bracket 31 Base part 32 Holding cylinder part 33 Connecting part 34 Gutter part 35 Recessed part 36 Supporting cylinder part 37, 3 a, 37b, 37c Protrusion 38 Inner peripheral surface side stepped portion 39 Outer peripheral surface side stepped portion 40 Notch portion 41 Locking groove 42 Front end surface 43 Retaining ring 44 Locking hole 45 Output side rolling bearing unit 46 Output side sealing unit 47 Input side rolling bearing unit 48 Input side sealing unit 49 Gutter 50 Loading nut 51 Oscillating frame 52 Ball bearing 53 Supply path 54 Notch 55a, 55b Recess 56 Connection plate 57 Column

Claims (5)

An input shaft, an output shaft, a sun roller, an annular roller, a plurality of intermediate rollers, and a loading cam device;
Of these, the sun rollers are concentric to each other with a pair of sun roller elements divided in the axial direction around the input shaft, with a gap between the tip surfaces of the elements. The outer peripheral surfaces of the two sun roller elements are inclined surfaces that are inclined in a direction in which the outer diameter decreases toward the respective front end surfaces, and these two inclined surfaces are arranged. Rolling contact surface,
The annular roller is arranged concentrically with the sun roller around the sun roller, has an inner peripheral surface as a rolling contact surface, and is connected concentrically with the output shaft via a connection bracket, It can rotate with this output shaft,
Each of the intermediate rollers is centered on a rotation shaft disposed in parallel with the input shaft at a plurality of locations in the circumferential direction of the annular space between the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller. In a state of being rotatably supported, each outer peripheral surface is in rolling contact with the outer peripheral surface of the sun roller and the inner peripheral surface of the annular roller,
The loading cam device is provided between a movable sun roller element, which is at least one of the sun roller elements, and the input shaft, and the movable sun roller is rotated along with the rotation of the input shaft. The element is rotated while being pressed in the axial direction toward the other sun roller element,
The intermediate rollers rotate around the rotation shafts while being pressed against the inner peripheral surface of the annular roller based on the pressing force generated by the loading cam device as the input shaft rotates.
The connection bracket includes a base portion connected to an end portion of the output shaft so as to be able to transmit torque, a holding cylinder portion disposed around the annular roller, and a connection portion connecting the base portion and the holding cylinder portion. The annular roller and the coupling bracket engage with protrusions formed at a plurality of circumferential positions of the annular roller and recesses formed at a plurality of circumferential directions of the holding cylinder portion. Friction roller type speed reducer that is connected to enable torque transmission.   The annular roller and the connecting bracket are recessed in a radial direction, formed at a plurality of circumferential positions on the outer circumferential surface of the annular roller, and at a plurality of circumferential positions on the inner circumferential surface of the holding cylinder portion. In this state, it is coupled so as to be able to transmit torque by engaging with a concave portion that is continuous in the axial direction. Of the inner peripheral surface of the holding cylinder portion, it is closer to the opening portion than the annular roller in the axial direction. The friction roller type speed reducer according to claim 1, wherein each of the protrusions is prevented from coming out of each of the recesses by a locked retaining ring.   The friction roller type speed reducer according to claim 2, wherein a notch portion that is recessed radially inward is provided at a top portion of each projection.   When the projections formed on the outer peripheral surface of the annular roller are viewed from the axial direction, the outer circumferential surfaces of the circumferential roller and the outer peripheral surface of the annular roller are smoothly connected by partial arcs, The friction roller type speed reducer according to claim 3, wherein the width dimension in the circumferential direction increases, and the notch formed at the top of each protrusion has a partial arc shape.   The annular roller and the connecting bracket are recessed in the axial direction at the protrusions formed at a plurality of circumferential positions on the axial side surface of the annular roller, and at a plurality of circumferential positions inside the holding cylinder portion. A retaining ring that is coupled to a recess formed in the above-described manner so as to be able to transmit torque and that is locked to a portion closer to the opening than the annular roller in the axial direction on the inner peripheral surface of the holding cylinder portion. The friction roller type speed reducer according to claim 1, wherein the protrusions prevent the protrusions from coming out of the recesses.

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