JP5088303B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement of a toroidal type continuously variable transmission used as an automatic transmission for an automobile. Specifically, the power roller is smoothly displaced with respect to the trunnion to achieve a structure that can ensure high transmission efficiency.

[Description of prior art]
The use of a toroidal type continuously variable transmission as an automobile transmission is described in many publications such as Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, and has been well-known in some implementations. is there. FIG. 11 shows a basic configuration of a toroidal type continuously variable transmission that is currently being implemented. First, this conventional structure will be briefly described. A pair of input side disks 1a and 1b with respect to the input rotation shaft 2, each of which is a toroidal curved surface (concave arc-shaped concave surface) and corresponding to one axial side surface recited in the claims. In a state where the three and three are opposed to each other, concentric and synchronized rotation is supported freely.

  An output cylinder 5 having an output gear 4 fixed to the outer peripheral surface of the intermediate portion is supported around the intermediate portion of the input rotary shaft 2 so as to freely rotate with respect to the input rotary shaft 2. Further, output side disks 6 and 6 are supported at both ends of the output cylinder 5 so as to be rotatable in synchronization with the output cylinder 5 by spline engagement. In this state, each of the output side inner surfaces 7 and 7 of the output side disks 6 and 6, each of which is a toroidal curved surface and corresponding to one axial side surface recited in the claims, is the both input side inner side surfaces. 3 and 3 are opposed.

  Further, two power rollers 8 and 8 each having a spherical convex surface on each of the peripheral surfaces (cavities) between the input side and output side inner side surfaces 3 and 7 around the input rotation shaft 2 are provided. It is arranged. The power rollers 8 and 8 are respectively connected to the inner surfaces of the trunnions 9 and 9 via support shafts 10 and 10 whose base half and tip half are eccentric and a plurality of rolling bearings. 10 is supported in such a manner that it can be rotated about the front half of the front half and a small amount of swinging about the base half of each of the support shafts 10 and 10.

  The trunnions 9 and 9 are swingable and displaceable around the tilting shafts provided concentrically for each trunnion 9 and 9 at both ends in the length direction (front and back direction in FIG. 11). is there. The operation of swinging (tilting) each of the trunnions 9 and 9 is performed by displacing each of the trunnions 9 and 9 in the axial direction of each of the tilt shafts by a hydraulic actuator. At the time of shifting, the trunnions 9 and 9 are displaced in the axial direction of the tilt shafts by supplying and discharging pressure oil to and from the actuators. As a result, the direction of the force acting in the tangential direction of the contact portion (traction portion) between the peripheral surface of each of the power rollers 8 and 8 and each of the input side and output side inner surfaces 3 and 7 changes (side slip occurs). Therefore, the trunnions 9, 9 are oscillated and displaced about the tilt axes.

  During operation of the toroidal-type continuously variable transmission as described above, one input side disk 1a is rotated by the drive shaft 11 via a loading cam type pressing device 12 (see FIG. 11). As a result, the pair of input-side disks 1a and 1b supported at both ends of the input rotation shaft 2 rotate synchronously while being pressed toward each other. Then, this rotation is transmitted to the output side disks 6 and 6 through the power rollers 8 and 8 and is taken out from the output gear 4.

  When the ratio of the rotational speed between the input rotary shaft 2 and the output gear 4 is changed, and when deceleration is first performed between the input rotary shaft 2 and the output gear 4, the trunnions 9, 9 are arranged as shown in FIG. The power rollers 8 and 8 are swung to the positions shown in FIG. 3 so that the peripheral surfaces of the input-side discs 1a and 1b and the output-side discs 6 and 6 It is made to contact | abut to the outer peripheral side part of the output side inner surfaces 7 and 7, respectively. On the contrary, when the speed is increased, the trunnions 9 and 9 are swung in the direction opposite to that shown in FIG. 11, and the peripheral surfaces of the power rollers 8 and 8 are input to the input disks 1a and 1b. It is made to contact | abut to the outer peripheral part of the side inner side surfaces 3 and 3, and the center side part of the output side inner side surfaces 7 and 7 of the said output side discs 6 and 6, respectively. An intermediate speed ratio (transmission ratio) can be obtained between the input rotary shaft 2 and the output gear 4 by setting the swing angles of the trunnions 9 and 9 to an intermediate position.

  During operation of the toroidal type continuously variable transmission as described above, the members used for power transmission, that is, the input side and output side disks 1a, 1b, 6 and the power rollers 8, 8 are It is elastically deformed based on the pressing force (thrust) generated by the pressing device 12. And along with this elastic deformation, each said disk 1a, 1b, 6 is displaced to an axial direction. Further, the pressing force generated by the pressing device 12 increases as the torque transmitted by the toroidal continuously variable transmission increases, and the amount of elastic deformation of each member increases accordingly. Accordingly, in order to properly maintain the contact state between the input and output side surfaces 3 and 7 and the peripheral surfaces of the power rollers 8 and 8 irrespective of the torque fluctuation, 8 is required to displace the disc 8 in the axial direction of the discs 1a, 1b, 6 with respect to the trunnions 9, 9. In the case of the first example of the conventional structure shown in FIG. 11, the first half of each of the support shafts 10 and 10 that support the power rollers 8 and 8 is also oscillated and displaced about the base half. Thus, the power rollers 8, 8 are displaced in the axial direction.

  On the other hand, Patent Document 3 discloses a toroidal-type continuously variable transmission in which the change of the gear ratio and the displacement of each power roller in the axial direction of each disk on the input side and output side are performed by completely different mechanisms. The machine is listed. The toroidal type continuously variable transmission of the second example of this conventional structure includes a speed change mechanism as shown in FIGS. In the case of the second example of the conventional structure shown in FIGS. 12 to 13, the swing frame 13 is disposed around the input rotation shaft 2 between the input side and output side disks 1, 6. Can be swung around the center. The three trunnions 9a, 9a are rotatably supported between the support plate portions 14, 14 provided at the radially outer end of the swing frame 13 on the inner side surfaces thereof. Is supported so as to be able to swing only about the tilting shafts 15 and 15 provided at both ends. These trunnions 9a and 9a are not displaced in the axial direction of the tilting shafts 15 and 15 with respect to the swinging frame 13, unlike the structure shown in FIG. In this state, the extension lines α and α of the central axes of the power rollers 8 a and 8 a intersect on the central axes β of the disks 1 and 6.

  Of the tilting shafts 15 and 15, the remaining tilting shafts 15 and 15 other than the two tilting shafts 15 and 15 located at the upper end of FIGS. 12 to 13 include sector gears 16 and 16a. Is fixed. And the sector gears 16 and 16a regarding the trunnions 9a and 9a adjacent in the circumferential direction are meshed | engaged. With this configuration, all trunnions 9a, 9a are inclined at the same angle in the same direction with respect to the direction in which the gear ratio is changed. Furthermore, any one of the sector gears 16 and 16a (lower right part in FIGS. 12 to 13) is connected to a tilt shaft 15 to which the sector gear 16a is fixed by a cam device 17 and an actuator 18. Oscillate around the center.

  The cam device 17 includes a cam follower 19 supported by the one sector gear 16a and a cam member 21 fixed to the inner surface of a housing 20 housing a toroidal-type continuously variable transmission. The cam groove 22 provided in the cam member 21 is engaged with the cam follower 19. The actuator 18 is a hydraulic double-acting type, and the movement of the pin 24 engaged with the long hole provided in the piston 23 is transmitted to the swing frame 13 through the coupling bracket 25, and this swing is performed. The frame 13 is swung around the input rotation shaft 2. As the swing frame 13 swings, the positional relationship between the cam follower 19 supported by the one sector gear 16 a and the cam groove 22 changes, and the sector gear 16 a is centered on the tilt shaft 15. Swing. Further, the movement of the sector gear 16a is transmitted to all trunnions 9a and 9a via the remaining sector gears 16 and 16. As a result, the power rollers 8a and 8a supported on the inner surfaces of the trunnions 9a and 9a have the same direction as to the direction in which the gear ratio between the input and output disks 1 and 6 changes. And the gear ratio is adjusted to a desired value.

  In the structure described in Patent Document 3 as described above, the power rollers 8a and 8a only swing in the front and back direction in FIG. 13 with respect to the relative positional relationship with the swing frame 13 at the time of shifting. . In other words, the power rollers 8a and 8a are displaced with respect to the swing frame 13 (along with the swing frame 13 in the rotational direction or the counter-rotation direction of the input rotary shaft 2 for the speed change operation). Even so, the tilting shafts 15 and 15 are not displaced in the axial direction (perpendicular to the extension lines α and α). The swing frame 13 is supported at a position between the input side and output side disks 1 and 6 so as to be swingable and displaceable by an angle required for shifting. There is no displacement in the axial direction of 1 and 6 (front and back direction in FIG. 13). Therefore, the trunnions 9a and 9a are not displaced in the axial direction of the disks 1 and 6.

  On the other hand, during operation of the toroidal continuously variable transmission, the surface pressure of the rolling contact portion (traction portion) between the inner side surfaces 3, 7 of the disks 1, 6 and the peripheral surfaces of the power rollers 8a, 8a is secured. The members 1, 6, 8a are elastically deformed by the force applied for this purpose. And each of these power rollers 8a and 8a is displaced in the front and back direction of FIG. In the case of the structure shown in FIG. 11, the power rollers 8 and 8 are supported by the support shafts (eccentric shafts) 10 and 10 in which the base half and the front half are eccentric with respect to the trunnions 9 and 9, respectively. By supporting the swingable displacement, the power rollers 8 and 8 can be displaced in accordance with the elastic deformation of the constituent members. However, in the case of the structure shown in FIGS. 12 to 13, it is not possible to employ a structure that only allows the rocking displacement of the power rollers 8 a and 8 a by the eccentric shaft.

  The reason for this is that, in the structure in which each of the power rollers 8a and 8a is simply swung by the eccentric shaft, each of the power rollers 8a and 8a is tilted on the basis of the arc motion having the eccentric amount as the rotation radius. This is because although the shafts 15 and 15 are displaced slightly in the axial direction (perpendicular to the extension lines α and α). As described with reference to the structure shown in FIG. 11, when the power rollers 8a and 8a are displaced in the axial direction of the tilt shafts 15 and 15, side slips are generated in the traction portions. The trunnions 9a and 9a are applied with force in the direction of swinging around the tilt shafts 15 and 15 (directions for changing the gear ratio) via the power rollers 8a and 8a. Such a force is generated even when the displacement is about 0.1 to 0.2 mm. Naturally, it is not preferable to continue the operation of the toroidal type continuously variable transmission in a state where the side slip as described above occurs and the force as described above is applied. Specifically, the side slip is associated with a decrease in transmission efficiency and durability, and the force is associated with an increase in force that is actually required when changing the gear ratio.

For this reason, in the structure described in Patent Document 3, the power rollers 8a, 8a among the power rollers 8a, 8a of the members 1, 6, 8a are elastically deformed as shown in FIGS. Is displaced only in the axial direction (front and back direction in FIG. 13) of both the input side and output side disks 1 and 6. The support shaft 10a used in this structure for rotatably supporting the power roller 8a with respect to the trunnion 9a includes a base portion 26 and a support shaft portion 27 that are eccentric to each other. On the other hand, a circular recess 28 is formed in the middle portion of the inner surface of the trunnion 9a. A circular (thick disk-shaped) crank member 29 is rotatably fitted in the circular recess 28. A circular hole 30 is formed in a part of the crank member 29 at a position deviated from the center of the crank member 29. Eccentricity [delta] ₂ of the central axis X ₃₀ of the central axis X ₂₉ and the circular hole 30 of the outer peripheral surface of the crank member 29, the eccentricity of the central axis X ₂₇ of the central axis X ₂₆ and the support shaft portion 27 of the base 26 It is equal to the quantity δ ₁ (δ ₂ = δ ₁ ). The base portion 26 is fitted in the circular hole 30 so as not to rattle and swingable. Therefore, consistent with one another and the central axis X ₂₆ and the central axis X ₃₀ of the circular hole 30 of the base 26. Of course, the center axis X ₈ of the power roller 8 a rotatably supported around the support shaft portion 27 coincides with the center axis X ₂₇ of the support shaft portion 27.

  Further, a long hole 31 extending in the axial direction of the tilting shafts 15 and 15 is formed in a part of the trunnion 9a aligned with the bottom corner of the circular recess 28, and the bottom surface of the circular recess 28 and the trunnion It forms in the state which communicates with the outer surface of 9a. A guide rod 32 projecting at one corner of the base end surface {the right end surface of FIG. 15B) of the base portion 26 of the support shaft 10a is formed in the long hole 31, and the length of the long hole 31 is set. A displacement in the direction (the axial direction of each of the tilting shafts 15, 15 and the vertical direction in FIG. 15) is supported.

In the case of the structure described in Patent Document 3, the input side and output side inner side surfaces 3 and 7, which are axial side surfaces of the input side and output side discs 1 and 6, are configured as described above. Accompanying the axial displacement, the power roller 8a is displaced only in the axial direction as shown by an arrow a in FIG. When the power roller 8a is displaced in the direction of the arrow a, the guide rod 32 is moved to the tilt shafts 15 and 15 inside the elongated hole 31 as shown by an arrow b in FIG. Displacement in the axial direction. At this time, the arcuate movement based on the amount of eccentricity [delta] ₂ of the central axis X ₃₀ of the circular hole 30 around the center axis X ₂₉ of the outer peripheral surface of the crank member 29, the central axis X ₂₆ of the base 26 of the support shaft portion 27 The arc motion based on the eccentric amount δ ₁ with respect to the central axis X ₂₇ is canceled out, and the support shaft portion 27 is caused to linearly move.

  Whether the first example of the conventional structure shown in FIG. 11 or the second example of the conventional structure shown in FIGS. 12 to 16, the power rollers 8, 8 a are connected to the shafts of the disks 1, 1 a, 1 b, 6. The contact state between each of the disks 1, 1a, 1b, 6 and the peripheral surface of each of the power rollers 8, 8 can be properly maintained regardless of changes in the amount of elastic deformation of the constituent members. However, in any structure, the structure for displacing each of the power rollers 8 and 8 in the axial direction is complicated, and parts production, parts management, and assembly work are troublesome, and cost increases. Unavoidable. In Patent Document 4, a linear motion type rolling bearing is provided between an inner surface of a trunnion and an outer ring of a thrust ball bearing for rotatably supporting the power roller, whereby the shaft of each disk of the power roller is provided. A structure that allows directional displacement is described. Even the structure described in Patent Document 4 has the same problem.

[Description of Prior Invention]
As a technique for solving such a problem, there is an invention disclosed in Japanese Patent Application No. 2006-250530 (Japanese Patent Laid-Open No. 2008-25821). An example of the structure of the prior invention will be described with reference to FIGS. The feature of the toroidal-type continuously variable transmission of the prior invention is that the power roller 8b is supported with respect to the trunnion 9b so as to be capable of axial displacement of the input side and output side disks 1a, 1b, 6 (see FIG. 11). In the structure. The structure and operation of the toroidal-type continuously variable transmission as a whole are the same as those conventionally known, including the structure shown in FIGS. For this reason, the illustration and description of the parts configured in the same manner as in the prior art will be omitted or simplified, and the following description will focus on the characteristic parts of the prior invention structure.

The trunnion 9b constituting the toroidal-type continuously variable transmission of the previous invention exists between a pair of tilting shafts 15 and 15 provided concentrically at both ends, and between these two tilting shafts 15 and 15. Further, at least the inner side (upper side in FIGS. 18, 20 to 22) in the radial direction (the vertical direction in FIGS. The support beam portion 34 is provided. The two tilting shafts 15 and 15 swing to the yoke (not shown) or the support plate portions 14 and 14 (see FIGS. 12 to 13) of the swing frame 13 via radial needle bearings 35 and 35, respectively. Support possible. Further, as shown in FIGS. 18 and 21, the central axis A of the cylindrical convex surface 33 is parallel to the central axes B of the both tilting axes 15, 15, and the central axes B of the both tilting axes 15, 15 are. Rather than the outer side (the lower side of FIGS. 18, 20 to 22) in the radial direction of each of the disks 1a, 1b, and 6. Further, a concave portion 38 having a partial cylindrical surface is formed across the outer surface in the radial direction on the outer surface of the outer ring 37 constituting the thrust ball bearing 36 provided between the support beam portion 34 and the outer surface of the power roller 8b. It is provided in the state. Then, the concave portion 38 is engaged with the cylindrical convex surface 33 of the support beam portion 34 so that the outer ring 37 can be oscillated and displaced in the axial direction of the discs 1a, 1b, 6 with respect to the trunnion 9b. I support it. In the case of this example, the curvature radius r ₃₈ of the cross-sectional shape of the concave portion 38 and the curvature radius r ₃₃ (FIG. 22) of the cross-sectional shape of the cylindrical convex surface 33 are made to coincide with each other, The convex surface 33 is in direct contact. Incidentally, the curvature radius r ₃₈ of the concave portion 38 side, the curvature of the cylindrical convex surface 33 side larger than the radius _{r 33 (r 38> r 33} ) and may be.

  In the case of this example, a support shaft 10b is fixed to the central portion of the inner surface of the outer ring 37, and the power roller 8b is mounted around the support shaft 10b as a radial needle bearing. 39 is rotatably supported via 39. Further, a downstream oil supply passage 40 for supplying lubricating oil to the thrust ball bearing 36 and the radial needle bearing 39 is provided inside the outer ring 37 and the support shaft 10b. An upstream oil supply passage 41 connected to the downstream oil supply passage 40 is provided. A recess 42 that is long in the swinging direction of the outer ring 37 is formed on the outer surface of the outer ring 37 that surrounds the upstream end opening of the downstream oil supply passage 40, regardless of the swinging displacement of the outer ring 37. The oil passages 40 and 41 are in communication with each other. Further, an oil supply pipe 43 connected to the upstream oil supply passage 41 is provided outside the support beam portion 34. The upstream end of the oil supply pipe 43 is opened to the inner diameter side of the pulley 44 provided at the end of the trunnion 9b for bridging the synchronous cable, and the lubricating oil is supplied through the inner diameter side of the pulley 44. It is possible.

  In the case of the prior invention, a pair of stepped surfaces facing each other at the continuous portion between the both end portions of the support beam portion 34 and the pair of tilting shafts 15 and 15 on the inner side surface of the trunnion 9b. 45 and 45 are provided. The distance between the two step surfaces 45 and 45 is slightly larger (for example, about several tens of μm) than the outer diameter of the outer ring 37. Therefore, the outer peripheral surface of the outer ring 37 is in contact with or in close proximity to the step surfaces 45 and 45 in a state where the concave portion 38 and the cylindrical convex surface 33 are in contact with each other. That is, the outer ring 37 is assembled between the step surfaces 45 and 45 so that the traction force applied to the outer ring 37 from the power roller 8b can be supported by any of the step surfaces 45 and 45.

According to the toroidal-type continuously variable transmission of the prior invention configured as described above, the power roller 8b is displaced in the axial direction of each of the disks 1a, 1b, 6 to change the amount of elastic deformation of each component. Regardless, the structure that can properly maintain the contact state between the peripheral surface of the power roller 8b and the disks 1a, 1b, and 6 can be configured simply and at low cost.
That is, during operation of the toroidal type continuously variable transmission, each of the power rollers 8b is connected to each of the disks 1a, 1b, 6 on the basis of elastic deformation of the input side, output side disks 1a, 1b, 6, and each power roller 8b. When it is necessary to displace axially, the outer ring 37 of the thrust ball bearing 36 that rotatably supports each of the power rollers 8b is provided with a concave portion 38 and a supporting beam portion 34 provided on the outer surface. While sliding the contact surface with the cylindrical convex surface 33, the cylindrical convex surface 33 is oscillated and displaced about the central axis a. Based on this oscillating displacement, a portion of the peripheral surface of each power roller 8b that is in rolling contact with one axial side surface of each disk 1a, 1b, 6 is the axial direction of each disk 1a, 1b, 6. To maintain the above contact state properly. As described above, the central axis A of the cylindrical convex surface 33 is greater than the central axes B of the tilting shafts 15 and 15 that are the swing centers of the trunnions 9b during the shifting operation. It exists outside in the radial direction. Therefore, the rocking radius of the rocking displacement centered on the central axis A of the cylindrical convex surface 33 is larger than the rocking radius at the time of the shifting operation, and the input side disks 1a and 1b and the output side disk 6 Has little effect on the change in transmission ratio during the period (can be neglected or remain within an easily modifiable range).

In this way, the processing of the concave portion 38 and the cylindrical convex surface 33 required for maintaining the contact state properly is easy, and no special parts are required. For this reason, it can be configured simply and at low cost.
Further, since the traction force applied from the power roller 8b to the outer ring 37 is supported by any one of the step surfaces 45, the power roller 8b is displaced in the axial direction of the tilt shafts 15 and 15 on the inner surface of the trunnion 9b. This ensures the stability of the shifting operation of the toroidal type continuously variable transmission.

  When the toroidal continuously variable transmission according to the present invention is operated, the traction force applied to the outer ring 37 from the power roller 8b is supported by any one of the step surfaces 45 as described above. The traction force, which is called 2Ft in the technical field of toroidal continuously variable transmissions, is considerably large. On the other hand, the outer peripheral surface 46 of the outer ring 37 is a convex cylindrical surface, whereas the two step surfaces 45 and 45 enable the outer ring 37 to be oscillated and displaced about the support beam portion 34. It is necessary to provide flat surfaces parallel to each other that exist in a direction orthogonal to the central axis of the support beam portion 34. For this reason, the contact area between the step surface 45 and the outer peripheral surface 46 is small, and when the traction force applied to the outer ring 37 is supported by the step surface 45, the contact between the step surface 45 and the outer peripheral surface 46 is small. A large surface pressure acts on the contact portion. If the stepped surface 45 and the outer peripheral surface 46 slide with a change in the gear ratio of the toroidal type continuously variable transmission in a state where a large surface pressure is applied to the abutting portion, the both surfaces 45, 46 are brought to an early stage. Damage such as wear may occur. Moreover, even when not sliding, an indentation may occur on the stepped surface 45 side.

JP-A-3-74667 JP 2001-165262 A German Patent Application Publication No. 10246432 (DE10246432A1) JP 2003-294099 A Motoo Aoyama, “Bessed Best Car Red Badge Series 245 / A book that understands the latest mechanics of cars”, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001, p. 92-93 Hirohisa Tanaka, “Toroidal CVT”, Corona Inc., July 13, 2000

  In view of the circumstances as described above, the present invention displaces each power roller in the axial direction of each disk, and regardless of the change in the amount of elastic deformation of each constituent member, the peripheral surface of each power roller and each of these disks The invention has been invented to realize a structure that can maintain a proper contact state with each other, can be configured simply and at low cost, and has excellent durability.

The toroidal type continuously variable transmission of the present invention includes at least a pair of disks, a plurality of trunnions, and a plurality of power rollers, as in the above-described conventionally known toroidal type continuously variable transmissions.
Of these, at least one pair of discs are supported concentrically and freely in relative rotation with each other in the state in which one side surface in the axial direction is a toroidal curved surface having an arcuate cross section.
Each trunnion is centered on a tilting shaft that is twisted with respect to the central axis of each disc at a plurality of locations in the circumferential direction between the axial side surfaces of each disc in the axial direction. The oscillating displacement is freely provided.
Further, each of the power rollers is rotatably supported on the inner surface of each of the trunnions via a thrust rolling bearing, and each circumferential surface having a spherical convex surface is applied to one side surface in the axial direction of the both disks. Touching.

Further, in the toroidal type continuously variable transmission according to the present invention, as in the above-described toroidal type continuously variable transmission according to the present invention, each of the trunnions is provided at the both ends concentrically with each other. The tilting shaft and the tilting shaft exist between the two tilting shafts, and at least the inner side surface in the radial direction of the two disks is parallel to the central axis of the two tilting shafts and is more than the central axis of the tilting shaft. And a support beam portion having a cylindrical convex surface having a central axis existing outside in the radial direction of the two disks.
Each thrust rolling bearing is provided between the support beam and the outer surface of each power roller. The outer ring is provided on the support beam and the inner surface of the outer ring. And a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway provided on the outer surface of the power roller.
Then, the outer ring has a swing displacement in the axial direction of the two discs with respect to each trunnion by engaging a concave portion having a partial cylindrical surface provided on the outer surface with a cylindrical convex surface of the support beam portion. Is supported by possible.
In addition, a pair of stepped surfaces facing each other are provided in the continuous portion between the both end portions of the support beam portion and the pair of tilting shafts on the inner side surface of each trunnion. A traction force applied to the outer ring from the power roller is engaged with a portion between the step surfaces so as to be supported by any of the step surfaces.

Furthermore, in the case of the toroidal continuously variable transmission according to the present invention, the radius of curvature in the circumferential direction of the outer peripheral surface of the outer ring facing the two step surfaces is made larger than the radius of curvature of the remaining portion. ing.
In this way, the outer peripheral surface and the two stepped surfaces are significantly increased to a degree that the radius of curvature of the portion facing the two step surfaces of the outer ring of the outer ring is larger than the curvature radius of the remaining portions. The contact area of the abutment portion can be increased (widened) to suppress wear on both sides.
Most preferably, as described in claim 2, a radius of curvature in the circumferential direction of a portion of the outer peripheral surface facing the two step surfaces is infinite, and the shape of this portion is parallel to the two step surfaces. A flat surface. In other words, flat surfaces parallel to each other are formed at two positions opposite to the diameter direction of the outer peripheral surface of the outer ring, each in a direction perpendicular to the central axis of the support beam portion.
Preferably, as described in claim 3, the outer circumferential surface of the outer ring is changed from a portion having a different radius of curvature in the circumferential direction (a portion provided with a flat surface in the case of claim 2) in the axial direction. A cylindrical surface having a circular cross-section in a direction perpendicular to the central axis is provided in a portion that is disengaged in order to bring the shoe into contact (sliding contact) when processing the outer ring.

According to the toroidal type continuously variable transmission of the present invention configured as described above, each power roller is displaced in the axial direction of each disk in the same manner as the above-described toroidal type continuously variable transmission according to the previous invention. Regardless of the change in the amount of elastic deformation of each member, a structure capable of maintaining the contact state between the peripheral surface of each power roller and each disk properly can be configured simply and at low cost.
That is, when the toroidal type continuously variable transmission is operated, if it is necessary to displace the power rollers in the axial direction of the disks based on the elastic deformation of the input and output disks and the power rollers, The outer ring of each thrust rolling bearing that rotatably supports the power roller is oscillated and displaced about the engaging portion between the concave portion of the partial cylindrical surface provided on the outer surface and the cylindrical convex surface of the support beam portion. Based on this swing displacement, the portion of the peripheral surface of each power roller that is in rolling contact with one axial side surface of each disk is displaced in the axial direction of each disk, and the contact state is maintained appropriately. To do. The central axis of the cylindrical convex surface is present on the outer side in the radial direction of each disk with respect to the central axis of the tilting axis that becomes the center of oscillation of each trunnion during the shifting operation. Therefore, the rocking radius of the rocking displacement centered on the central axis of the cylindrical convex surface is larger than the rocking radius at the time of the gear shifting operation, and the gear ratio between the input side disk and the output side disk is It has little effect on variability (it can be ignored or can be easily corrected).
In this way, the processing of the concave portion and the cylindrical convex surface, which is necessary for maintaining the contact state properly, is easy, and no special parts are required. For this reason, it can be configured simply and at low cost.

Furthermore, according to the structure of the present invention, the contact area between the outer peripheral surface of the outer ring of each thrust rolling bearing and the step surface provided on the inner surface of each trunnion can be increased. For this reason, even when a large traction force called 2Ft is supported by the contact portion between the outer peripheral surface and the step surface during operation of the toroidal continuously variable transmission, the surface pressure of the contact portion can be suppressed. As a result, it is possible to prevent the stepped surface from being damaged such as indentation or early wear.
The specification and drawings of Japanese Patent Application No. 2006-250530 described above describe a structure in which the traction force is transmitted from the outer ring to the trunnion by a thrust needle bearing or bracket provided between the trunnion and the outer ring. ing. According to such a structure, it is possible to prevent indentation and wear on the stepped surface as described above, but instead, the manufacturing cost increases due to an increase in the number of parts. In the case of the present invention, generation of the indentation and wear can be suppressed while suppressing such cost increase.

[First example of embodiment]
1 to 3 show a first example of an embodiment of the present invention corresponding to claim 1 only. The features of this example and the second to third examples to be described later are based on the steps of the outer peripheral surface 46 of the outer ring 37 constituting the thrust ball bearing 36 and the inner side surface of the trunnion 9b on the premise of the structure of the previous invention. It has a structure for ensuring the contact area with the surfaces 45 and 45. The structure and operation of other parts are the same as the structure according to the prior invention described with reference to FIGS. Therefore, with respect to the same parts as those of the structure according to the present invention, overlapping illustrations and descriptions will be omitted or simplified, and the following description will focus on the characteristic parts of this example.

Of the outer ring 37, traction force support is provided at the portions facing the step surfaces 45 and 45 at two positions opposite to the diameter direction of the portion of the outer ring 37 that is closest to the power roller 8b and has the largest outer diameter. Surfaces 47 and 47 are formed. Both the traction force support surfaces ₄₇ , ₄₇ are partially convex cylindrical surfaces like the outer peripheral surface 46 of the outer ring 37, but the respective radii of curvature R ₄₇ are the both traction force support surfaces of the outer peripheral surface 46. _{47 and 47} are larger than the radius of curvature r ₄₆ of the part deviating from ₄₇ (R ₄₇ > r ₄₆ ). That is, the center of curvature of the outer circumferential surface 46 that is out of the both traction force support surfaces 47, 47 exists at the point O on the central axis of the outer ring 37, whereas the both traction force support The center of curvature of the surfaces 47 and 47 exists on the far side from the point O on a virtual straight line α passing through the point O and parallel to the central axis of the support beam portion 34.

  In the state where the thrust ball bearing 36 having the outer ring 37 provided with the traction force support surfaces 47 and 47 as described above is assembled to the trunnion 9b, the both traction force support surfaces 47 and 47 are both stepped surfaces 45. 45, abut or face each other. That is, on the side that supports the traction force called 2Ft described above, the traction force support surface 47 and the step surface 45 abut, and the traction force transmitted from the power roller 8b to the outer ring 37 is It is transmitted to the trunnion 9b. On the other hand, the traction force support surface 47 and the step surface 45 on the opposite side are close to each other through a minute gap of about several tens of μm as described above. When the direction of torque passing through the toroidal type continuously variable transmission is reversed, such as when the engine brake is operated, the traction force support surface 47 and the step surface 45 on the opposite side come into contact with each other.

According to the structure of this example, since the radius of curvature R ₄₇ of both the traction force support surfaces _{47 and 47} is large, the contact area between the traction force support surface 47 on the side transmitting the traction force and the step surface 45 is widened. it can. For this reason, the surface pressure of the contact portion between the both surfaces 47 and 45 can be suppressed to prevent the stepped surface 45 from being damaged such as indentation or early wear.

Further, according to the structure of the present example, the width dimension (short diameter) D ₃₇ of the outer ring 37 in the axial direction of the support beam portion 34 can be increased by forming both the traction force support surfaces 47, 47. The traction force support surfaces 47, 47 can be made smaller than the case where they are not formed. Then, the distance D ₄₅ between the two step surfaces 45, 45 is extended by the amount that the width dimension D ₃₇ can be reduced, and further, the support beam portion 34 that exists between the two step surfaces 45, 45 exists. The axial length L ₃₄ can be shortened. As a result, the amount of elastic deformation of the support beam portion 34 based on the thrust load applied from the power roller 8b during operation of the toroidal type continuously variable transmission can be reduced. When the support beam portion 34 is elastically deformed, the distance between the two step surfaces 45, 45 is reduced although it is slightly. Accordingly, in order to prevent the outer ring 37 from being strongly clamped (engaged) between the two step surfaces 45, 45 in order to enable a speed change operation, the two step surfaces 45, 45 are connected to each other. The distance D ₄₅ (= L ₃₄ ) must be larger than the width dimension D _{37 of the} outer ring 37 in the axial direction of the support beam portion 34.

On the other hand, if the distance D ₄₅ is made larger than the width dimension D ₃₇ , the transmission torque of the toroidal continuously variable transmission is small, and the elastic deformation amount of the support beam 34 is small. The displaceable amount of the outer ring 37 along the support beam portion 34 is increased. When the displaceable amount of the outer ring 37 is increased, the power roller 8b supported by the thrust ball bearing 36 including the outer ring 37 is rotated when the torque transmission direction is reversed by the toroidal continuously variable transmission (for example, At the moment when “acceleration / deceleration” is switched), the support beam 34 is greatly displaced in the axial direction. The displacement in the axial direction leads to a change in the gear ratio of the toroidal-type continuously variable transmission. Therefore, in order to prevent the gear ratio from changing carelessly, the outer ring 37 is moved in the axial direction of the support beam 34. It is necessary to displace the trunnion 9b in the opposite direction by the amount displaced. If such an operation is required, the stability of the transmission ratio retention of the toroidal-type continuously variable transmission is lost when the torque transmission direction is reversed (control responsiveness to obtain a desired transmission ratio). Gets worse).

On the other hand, in the structure of this example, as described above, the axial length L ₃₄ of the support beam 34 can be shortened by forming the both traction force support surfaces 47 and 47. Therefore, the bending rigidity of the support beam portion 34 can be increased accordingly. Therefore, when the toroidal continuously variable transmission is operated, the extent to which the distance between the two step surfaces 45, 45 is reduced based on the elastic deformation of the support beam portion 34 can be kept small. Then, the distance D ₄₅ (= L ₃₄ ) between the two step surfaces 45, 45 can be set to the width dimension D of the outer ring 37 with respect to the axial direction of the support beam portion 34 in a torque non-transmitting state. _The degree to be larger than ₃₇ can be reduced. As a result, it is possible to reduce the displaceable amount of the outer ring 37 along the support beam portion 34 in a state where the transmission torque of the toroidal continuously variable transmission is small and the elastic deformation amount of the support beam portion 34 is small. In response to the torque reversal, control responsiveness for obtaining a desired gear ratio can be improved. In the case of this example, in order to change the gear ratio, the trunnion 9b is displaced in the axial direction of the tilt shafts 15 and 15 as in the first example of the conventional structure shown in FIG.

[Second Example of Embodiment]
FIGS. 4-8 has shown the 2nd example of embodiment of this invention corresponding to Claim 1,2. In the case of this example, the radius of curvature in the circumferential direction of the portion facing the pair of step surfaces 45, 45 provided on the inner surface of the trunnion 9b in the outer peripheral surface 46 of the outer ring 37 is infinite. . In this portion, a pair of traction force support surfaces 47a and 47a, which are flat surfaces parallel to the two step surfaces 45 and 45, are provided. In other words, they are flat surfaces parallel to each other at two positions on the diametrically opposite side of the outer circumferential surface 46 of the outer ring 37, each in a direction orthogonal to the central axis of the support beam portion 34 of the trunnion 9b. Both the traction force support surfaces 47a and 47a are formed.

In the case of this example, the contact area between the step surfaces 45 and 45 and the traction force support surfaces 47a and 47a can be made wider than in the case of the first example of the embodiment described above. . And damage of each of these surfaces 45 and 47a can be prevented more effectively. Further, the width D ₃₇ of the outer ring 37 with respect to the axial direction of the support beam 34 can be made smaller, the axial length L ₃₄ of the support beam 34 can be made shorter, and the bending rigidity of the support beam 34 can be made higher. Thus, the control responsiveness for obtaining a desired gear ratio at the time of torque reversal can be further improved. It should be noted that both end portions in the circumferential direction of the traction support surfaces 47a and 47a and the remaining portion of the outer peripheral surface 46 are smoothly continued by a convex curved surface, so that the lubricating oil is applied to the sliding portions of the surfaces 45 and 47a. Is preferable from the viewpoint of facilitating the incorporation of.
Since the configuration and operation of the other parts are the same as those in the first example of the above-described embodiment, redundant description is omitted.
In addition, the perspective view regarding the structure of this example is shown in FIGS. FIG. 6 shows that the members constituting the thrust ball bearing 36 and the power roller 8b are attached to the structure shown in FIG. FIG. 7 is a perspective view showing a state in which the thrust ball bearing 36 and the power roller 8b are separated from the trunnion 9b, and FIG. 8 is a state in which only the thrust ball bearing 36 and the power roller 8b are taken out. It is the perspective view shown by. 4 to 8 also, like FIGS. 1 to 5 described above, the same reference numerals are given to the same parts as the structure according to the previous invention.

[Third example of embodiment]
FIGS. 9-10 has shown the 3rd example of embodiment of this invention corresponding to Claims 1-3. In the case of this example, the axial direction of the outer ring 37 from the portion where the pair of traction force support surfaces 47a are provided in the outer peripheral surface of the outer ring 37 constituting the thrust ball bearing 36 (with respect to the radial direction of each disk). A shoe cylindrical surface 48 for abutting (sliding contact) with the shoe when the outer ring 37 is processed is provided on the part that is removed outward. The shoe cylindrical surface 48 is a cylindrical surface having a circular cross section in a direction perpendicular to the central axis of the outer ring 37, and has an outer diameter that is outside the outer peripheral surface of the portion where the traction force support surface 47a is provided. It is smaller than the diameter (diameter of circumscribed circle). Further, in the case of this example, the backing plate stepped surface 50 is continuously extended from the shoe cylindrical surface 48 through the chamfered portion 49 over the entire circumference radially outward of the outer surface of the outer ring 37. The outer ring 37 is provided so as to be orthogonal to the central axis. The step surface 50 for the backing plate is used to contact the backing plate when the outer ring 37 is processed, and to position the outer ring 37 in the axial direction.

In the case of this example, when the outer ring 37 is processed, a portion (for example, a center hole) for contacting the center for center processing is not provided (or a portion for contacting the center). In the processing of the outer ring 37, the shoe is brought into contact (sliding contact) with the shoe cylindrical surface 48, and the backing plate is brought into contact with the backing plate step surface 50. Can be done in the state. Therefore, the outer ring 37 can be processed with high accuracy.
Since the configuration and operation of the other parts are the same as those of the second example of the above-described embodiment, redundant description is omitted.

The side view which shows the 1st example of embodiment of this invention. The figure which abbreviate | omitted and showed some components of a power roller and a thrust ball bearing, and was seen from the upper direction of FIG. The figure seen from the same direction as FIG. 2 except a trunnion. The figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. The same figure as FIG. Similarly perspective view. The perspective view shown in the state which isolate | separated the thrust ball bearing and the power roller from the trunnion. The perspective view shown in the state which took out only a thrust ball bearing and a power roller, and was seen from the opposite side to FIGS. 6-7 regarding the axial direction of these both members. The figure similar to FIG. 7 which shows the 3rd example of embodiment of this invention. Similarly, the same figure as FIG. Sectional drawing which shows the 1st example of a conventional structure. The principal part perspective view which shows the 2nd example. The figure which took out a part of FIG. 12, and looked from the axial direction of each disc. The disassembled perspective view shown in the state which took out the trunnion and the power roller. (A) is the figure seen from the inner surface side of the trunnion, (B) is sectional drawing in the assembled state. (A) is the perspective view seen from the inner surface side of the trunnion in the same state, (B) is the perspective view seen from the outer surface side in the state which cut | disconnected a part. The principal part perspective view which shows an example of the structure of a prior invention. The front view. The top view seen from the upper part of FIG. The side view seen from the right side of FIG. AA sectional drawing of FIG. BB sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Input side disk 2 Input rotating shaft 3 Input side inner surface 4 Output gear 5 Output cylinder 6 Output side disk 7 Output side inner surface 8, 8a, 8b Power roller 9, 9a, 9b Trunnion 10, 10a, 10b Support shaft 11 Drive shaft 12 Press device 13 Oscillating frame 14 Support plate portion 15 Tilt shaft 16, 16a Sector gear 17 Cam device 18 Actuator 19 Cam follower 20 Housing 21 Cam member 22 Cam groove 23 Piston 24 Pin 25 Coupling bracket 26 Base 27 Support shaft portion 28 Circular concave portion 29 Crank member 30 Circular hole 31 Long hole 32 Guide rod 33 Cylindrical convex surface 34 Support beam portion 35 Radial needle bearing 36 Thrust ball bearing 37 Outer ring 38 Concave portion 39 Radial needle bearing 40 Downstream oil supply passage 41 Upstream side Oil supply path 42 Recess 4 Fueling pipe 44 pulley 45 stepped surface 46 outer circumferential surface 47,47a traction supporting surface 48 cylindrical surface 49 chamfered portion 50 backing plate for step surface for a shoe

Claims (3)

  At least one pair of discs that are concentrically supported by each other in a state in which one side surfaces in the axial direction, each of which is a toroidal curved surface having an arc-shaped cross section, are opposed to each other and freely rotatable relative to each other, and each of these discs in the axial direction. A plurality of trunnions provided freely at a plurality of locations in the circumferential direction between the side surfaces in the axial direction of the disc, with a swinging displacement centering on a tilting shaft located at a twisted position with respect to the central axis of each disk. And a plurality of powers that are rotatably supported on the inner side surfaces of the respective trunnions via thrust rolling bearings, and whose respective circumferential surfaces have spherical convex surfaces are in contact with one axial side surfaces of both disks. In the toroidal type continuously variable transmission provided with a roller, each trunnion exists between the pair of tilting shafts concentrically provided at both ends and the two tilting shafts. And at least the inner side surface in the radial direction of the two discs has a central axis that is parallel to the central axis of the two tilting shafts and outside the central axis of the tilting shafts in the radial direction of the two discs. Each of the thrust rolling bearings is provided between the support beam portion and the outer surface of each of the power rollers, and the support beam portion. An outer ring provided on the side, and a plurality of rolling elements provided between the outer ring raceway provided on the inner side surface of the outer ring and the inner ring raceway provided on the outer side surface of the power roller. The outer ring is configured such that the shafts of the two discs are engaged with the trunnions by engaging a concave portion having a partial cylindrical surface provided on an outer surface and a cylindrical convex surface of the support beam portion. Supports oscillating displacement with respect to direction Among the inner side surfaces of each trunnion, a pair of stepped surfaces facing each other is provided at a continuous portion between both end portions of the support beam portion and the pair of tilting shafts, and the outer ring has these A traction force applied to the outer ring from the power roller is engaged in a state where it can be supported by any one of the step surfaces between the two step surfaces. A toroidal-type continuously variable transmission characterized in that the radius of curvature in the circumferential direction of the portion to be operated is larger than the radius of curvature of the remaining portion.   The toroidal continuously variable transmission according to claim 1, wherein a radius of curvature in a circumferential direction of a portion facing both step surfaces is infinite, and a shape of this portion is a flat surface parallel to the both step surfaces.   A cross-section in a direction perpendicular to the central axis for abutting the shoe when machining the outer ring on a part of the outer ring of the outer ring that has a different radius of curvature in the circumferential direction. The toroidal continuously variable transmission according to any one of claims 1 to 2, wherein a cylindrical surface having a circular shape is provided.

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