JP5126206B2 - 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 so as to achieve a structure capable of ensuring high transmission efficiency and ensuring excellent durability.

  The use of toroidal continuously variable transmissions as automotive transmissions has been described in many publications and is partly implemented and well known. In particular, Patent Document 1 describes a toroidal continuously variable transmission having various structures. FIG. 5 shows a basic configuration of a toroidal type continuously variable transmission which is described in Patent Document 1 and is currently being implemented. First, the first example of 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 about the tilting shafts provided concentrically for each trunnion 9 and 9 at both ends in the length direction (front and back direction in FIG. 5). 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. 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 and 9 are 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. 5, 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 periphery side 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. 5, 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.

  In the case of the first example of such a conventional 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 both troublesome and costly. It is inevitable that it is bulky. As a technique for solving such a problem, Patent Document 1 describes a structure as shown in FIGS. Since the present invention improves the second example of the conventional structure shown in FIGS. 6 to 11, the second example of the conventional structure will be described next. The feature of the second example of this conventional structure is that the power roller 8a is supported by the trunnion 9a so that the axial displacement of each of the input side and output side disks 1a, 1b, 6 (see FIG. 5) is possible. The overall structure and operation of the toroidal type continuously variable transmission are the same as those of the first example of the conventional structure shown in FIG.

  The trunnion 9a constituting the second example of the conventional structure exists between a pair of tilting shafts 13 and 13 provided concentrically with each other at both ends, and between these tilting shafts 13 and 13, and at least A support having a cylindrical convex surface 14 on the inner side (upper side in FIGS. 7 and 9 to 11) in the radial direction (the vertical direction in FIGS. 7 and 9 to 11) of both the input side and output side disks 1 a, 1 b and 6. And a beam portion 15. Both the tilting shafts 13 and 13 are respectively connected to a yoke (not shown in the drawing because it has a well-known structure) or a support plate portion of a swing frame (FIGS. 71 and 72 of Patent Document 1) via radial needle bearings 16 and 16, respectively. Are supported so as to be able to swing.

Further, as shown in FIGS. 7 and 10, the central axis A of the cylindrical convex surface 14 is parallel to the central axis B of the both tilting shafts 13 and 13, and the central axis B of the both tilting shafts 13 and 13 is. Rather than the outer side (the lower side of FIGS. 7 and 9 to 11) in the radial direction of the disks 1 a, 1 b and 6. Further, a concave portion 19 having a partially cylindrical surface is formed across the outer surface in the radial direction on the outer surface of the outer ring 18 constituting the thrust ball bearing 17 provided between the support beam portion 15 and the outer surface of the power roller 8a. It is provided in the state. And this recessed part 19 and the cylindrical convex surface 14 of the said support beam part 15 are engaged, The rocking | displacement displacement regarding the axial direction of each said disk 1a, 1b, 6 is carried out for the said outer ring 18 with respect to the said trunnion 9a. I support it as possible. As the recess the radius of curvature r ₁₉ of the cross-sectional shape of 19 the radius of curvature r ₁₄ or more of the cross-sectional shape of the cylindrical convex surface 14 (r ₁₉ ≧ r _14), the recesses 19 and the cylindrical convex surfaces 14, the entire surface or the recess It is made to contact | abut directly in the bottom vicinity part of 19. FIG.

  Further, a support shaft 10a is fixed to the center of the inner surface of the outer ring 18 integrally with the outer ring 18, and the power roller 8a is rotatable around the support shaft 10a via a radial needle bearing 20. I support it. Further, a downstream oil supply passage 21 for supplying lubricating oil to the thrust ball bearing 17 and the radial needle bearing 20 is provided inside the outer ring 18 and the support shaft 10a. An upstream oil supply passage 22 connected to the downstream oil supply passage 21 is provided. These oil supply passages 21 and 22 communicate with each other regardless of the rocking displacement of the outer ring 18 through a concave hole 31 formed in the central portion of the concave portion 19, and further, outside the support beam portion 15. In addition, an oil supply pipe 23 connected to the upstream oil supply path 22 is provided. The upstream end portion of the oil supply pipe 23 is opened to the inner diameter side of the pulley 24 provided at the end portion of the trunnion 9 a for bridging the synchronous cable, and the lubricating oil is supplied through the inner diameter side of the pulley 24. Making it possible.

  Furthermore, a pair of stepped surfaces 25 and 25 facing each other are provided on the inner surface of the trunnion 9a at a continuous portion between both ends of the support beam 15 and the pair of tilting shafts 13 and 13. . Then, these stepped surfaces 25, 25 and the outer peripheral surface of the outer ring 18 constituting the thrust ball bearing 17 are brought into contact with or in close proximity to each other, and any traction force applied to the outer ring 18 from the power roller 8a is selected. These steps 25 and 25 can be supported.

According to the toroidal type continuously variable transmission of the second example of the conventional structure configured as described above, the power roller 8a is displaced in the axial direction of each of the disks 1a, 1b, 6 so as to elastically deform the constituent members. A structure that can appropriately maintain the contact state between the peripheral surface of the power roller 8a and each of the disks 1a, 1b, 6 regardless of the amount can be configured easily and at low cost.
That is, during operation of the toroidal type continuously variable transmission, each of the power rollers 8a is connected to each of the disks 1a, 1b, 6 based on the elastic deformation of the input side, output side disks 1a, 1b, 6, and each power roller 8a. When it is necessary to displace axially, the outer ring 18 of the thrust ball bearing 17 that rotatably supports the power rollers 8a is provided with a concave portion 19 and a supporting beam portion 15 provided on the outer surface of the cylindrical portion. While sliding the contact surface with the cylindrical convex surface 14, the cylindrical convex surface 14 is oscillated and displaced about the central axis a. Based on this oscillating displacement, the portion of the peripheral surface of each power roller 8a that is in rolling contact with the 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 14 is greater than the central axes B of the tilting shafts 13 and 13 that become the oscillation centers of the trunnions 9a 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 14 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).

When the second example of the conventional structure as described above is implemented, as shown in FIG. 11A, the curvature radius r ₁₉ of the sectional shape of the concave portion 19 is set to the curvature of the sectional shape of the cylindrical convex surface 14. Generally, it is larger than the radius r ₁₄ (r ₁₉ > r ₁₄ ). The reason for this is that when both the radii of curvature r ₁₉ and r ₁₄ are equal to each other (r ₁₉ = r ₁₄ ), the inner surface of the concave portion 19 and the cylindrical convex surface 14 come into contact with the entire surface of the portions facing each other, This is because it becomes difficult to feed the lubricating oil into the contact portion. Since the inner surface of the concave portion 19 and the cylindrical convex surface 14 are oscillated and displaced with each other in a state where they are in contact with each other with a large surface pressure, if the lubricating oil is poorly fed to the contact portions, metal contact will occur. It becomes easy to generate excessive wear based on it.

However, when large (r _19> r ₁₄₎ than the radius of curvature r ₁₄ of the cross-sectional shape of the cylindrical convex 14 also produces the following (1) such problem (2).
(1) The inner surface of the concave portion 19 and the cylindrical convex surface 14 are likely to be locally worn.
(2) It is difficult to ensure the durability of the thrust ball bearing 17.
Of these, the problem (1) occurs because the inner surface of the concave portion 19 and the cylindrical convex surface 14 are almost only at the bottom or near the bottom of the concave portion 19 as shown in FIG. This is because the contact is made in a state close to line contact, and the contact surface pressure becomes high.

  The reason why the problem (2) occurs is that the outer ring 18 is elastically deformed in a direction in which the inner side surface thereof is a partially convex cylinder based on a large thrust load applied to the thrust ball bearing 17 from the power roller 8a. It is to do. As is well known in the technical field of toroidal-type continuously variable transmissions, the thrust ball bearing 17 receives a large thrust load from the power roller 8a when the half-toroidal toroidal-type continuously variable transmission subject to the present invention is operated. Will be added. Based on this thrust load, the outer ring 18 constituting the thrust ball bearing 17 causes the inner surface of the concave portion 19 to follow the cylindrical convex surface 14 as shown exaggeratedly in FIG. These two surfaces are elastically deformed in a direction in which both surfaces are almost entirely contacted. With this elastic deformation, the distance between the outer ring raceway 28 provided on the inner side surface of the outer ring 18 and the inner ring raceway 27 provided on the outer side surface of the power roller 8a is not the same in the circumferential direction of the outer ring 18. become. With the difference in distance between the two tracks 28 and 27, the surface pressure of the rolling contact portion between the tracks 28 and 27 and the rolling surfaces of the balls 26 and 26 (see FIG. 12) is changed to the outer ring 18 described above. It becomes remarkably different with respect to the circumferential direction. Specifically, at the two positions opposite to the length direction of the trunnion 9a (the axial direction of the support beam portion 15) indicated by α and α in FIG. The surface pressure of the rolling contact portion with the rolling surface becomes excessive. As a result, the rolling fatigue life of both the tracks 28 and 27 is remarkably shortened at two positions on the opposite side in the longitudinal direction, which is an obstacle to ensuring the durability of the toroidal continuously variable transmission.

JP 2008-25821 A

  In view of the circumstances as described above, the present invention secures a contact area between the inner surface of the concave portion formed on the outer surface of the outer ring constituting the thrust ball bearing and the cylindrical convex surface provided on the support beam portion constituting the trunnion. The invention was invented to suppress wear on both sides and to suppress the elastic deformation of the outer ring to ensure the durability of the thrust ball bearing and to improve the durability of the toroidal continuously variable transmission as a whole. It is.

The toroidal type continuously variable transmission of the present invention is similar to the conventional toroidal type continuously variable transmission described in Patent Document 1 described above, and includes at least a pair of disks, a plurality of trunnions, and a plurality of trunnions. A power roller.
Each of these disks is supported concentrically and freely in relative rotation with the axial one side surfaces facing each other, each of which 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.
Each such trunnion exists between the pair of tilting shafts concentrically provided at both ends, and between the two tilting shafts, and at least the inner side surface in the radial direction of the two disks. And a support beam portion having a cylindrical convex surface having a central axis that is parallel to the central axis of the two tilting axes and that is present outside the central axis of the tilting axes with respect to the radial direction of the two disks.
Each of the power rollers is rotatably supported on the inner surface of each trunnion via a thrust rolling bearing, and each circumferential surface formed as a spherical convex surface is in contact with one axial side surface of both disks. Touching.
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. The outer ring can be displaced in the axial direction of the two discs with respect to each trunnion by engaging a concave portion provided on the outer surface of the outer ring with a cylindrical convex surface of the support beam. I support it.

In particular, in the toroidal continuously variable transmission according to the present invention, the concave portions provided on the outer surface of the outer ring are provided on both side portions in the width direction, and the curvature radius of the cross-sectional shape is greater than the curvature radius of the cylindrical convex surface. Also, it has a Gothic arch-like cross-sectional shape with a large pair of side concave curved surface portions. And the recessed part provided in the outer surface of the said outer ring | wheel and the cylindrical convex surface of the said support beam part are made to contact | abut on the said both side concave curved surface part.
When implementing such a toroidal type continuously variable transmission according to the present invention, it is preferable that the curvature radius of the cross-sectional shape is cylindrical between the both side concave curved surface portions as in the invention described in claim 2. A central concave curved surface portion smaller than the radius of curvature of the convex surface is present. And the center side edge of the said both side concave curved surface part and the both side edges of this central concave curved surface part are made to continue smoothly.
In addition, the structure for supporting the traction force applied to the outer ring from the power roller is not particularly limited. However, in order to simply configure this structure, as in the case of the second example of the conventional structure described above, of the inner surface of each trunnion, the both ends of the support beam and the both tilting shafts A pair of step surfaces facing each other are provided in the continuous portion. Then, the outer ring is engaged with a portion between these step surfaces so that the traction force applied to the outer ring from the power roller can be supported by any step surface.

According to the present invention configured as described above, a toroidal type continuously variable transmission having sufficient durability can be realized.
That is, in the case of the toroidal-type continuously variable transmission according to the present invention, the recess formed in the outer surface of the outer ring constituting the thrust ball bearing is provided with a pair of side concave curved surface portions, and the cross-sectional shape is a Gothic arch shape. Therefore, the inner surface of the recess and the cylindrical convex surface provided on the support beam portion constituting the trunnion abut at two positions in the circumferential direction of both surfaces. For this reason, the contact area of these both surfaces can be ensured and abrasion of these both surfaces can be suppressed.
Further, since the both surfaces are brought into contact with each other at two positions that are separated from each other in the circumferential direction, even when a large thrust load is applied to the outer ring, the outer ring narrows the opening width of the recess. It is possible to suppress elastic deformation in the direction of the movement. Therefore, the extent to which the distance 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 is not the same in the circumferential direction of both raceways can be suppressed. For this reason, it can prevent that the surface pressure of the rolling contact part of these both track | trucks and the rolling surface of each ball | bowl is partly excessive. As a result, it is possible to ensure the durability of the thrust ball bearing, and thus the durability of the toroidal continuously variable transmission incorporating the thrust ball bearing.

  Further, as in the invention described in claim 2, if the central side edge of the both side concave curved surface portion and the both side edges of the central concave curved surface portion are smoothly continuous, the inner surface of the concave portion and the support beam portion Even when a large force in a direction away from each other is applied between the concave curved surfaces on both sides along with the pressing with the cylindrical convex surface, the stress applied to the bottom portion of the concave portion or the vicinity thereof can be reduced. As a result, it is possible to prevent the outer ring from being damaged such as a crack.

The perspective view which looked at the trunnion which supported the power roller via the thrust ball bearing which shows an example of embodiment of this invention from the radial inside of each disk. The expanded XX sectional drawing of FIG. The perspective view shown in the state which took out the outer ring | wheel which comprises a thrust ball bearing, and was seen from the opposite side to FIG. The figure shown in the state which took out the outer ring | wheel which comprises a thrust ball bearing from FIG. Sectional drawing which shows the 1st example of a conventional structure. The perspective view which looked at the trunnion which supported the power roller via the thrust ball bearing which shows the 2nd example of the conventional structure from the radial direction outer side of each disk. Similarly, the front view shown in the state seen from the circumferential direction of the disk. The top view seen from the upper part of FIG. The side view seen from the right side of FIG. YY sectional drawing of FIG. FIG. 8 is a view corresponding to the ZZ cross section of FIG. 7, and shows a state before a thrust load is applied from the power roller to the thrust ball bearing, and a view after the thrust load is applied (B). FIG. 9 is a view seen from the same direction as FIG. 8 except for the power roller and the pulley in order to show a portion where the surface pressure of the rolling contact portion increases with elastic deformation of the outer ring.

  1 to 4 show an example of an embodiment of the present invention. The feature of the present invention including this example is that the outer ring 18a and the outer ring 18a and the outer ring are formed by devising the shape of the inner surface of the recess 19a formed on the outer surface of the outer ring 18a over the diameter direction of the outer ring 18a. The durability of the thrust ball bearing 17a including 18a is ensured. Since the structure and operation of the other parts are the same as those of the second example of the conventional structure shown in FIGS. 6 to 11 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The description will focus on the features of this example.

In the structure of this example, the inner surface of the concave portion 19a is not a single cylindrical surface, but a pair of side concave curved surface portions 29, 29 and a central concave curved surface portion 30 that are smoothly continuous with a Gothic arch-shaped cross section. It has a shape. Among these, the both sides concave portions 29 and 29 are provided in the width direction both sides of the recess 19a, the radius of curvature r ₂₉ of the cross-sectional shape, a cylindrical convex surface of the supporting beam portion 15 constituting the trunnions 9a larger than the radius of curvature r ₁₄ of the outer peripheral surface of _{14 (r 29> r 14)} . In contrast, the central concave surface portion 30 is provided in the widthwise central portion of the recess 19a, the radius of curvature r ₃₀ of the cross-sectional shape, than the radius of curvature r ₁₄ of the outer peripheral surface of the cylindrical convex surface 14 Is also small (r ₃₀ <r ₁₄ ). The both side concave curved surface portions 29, 29 and the central concave curved surface portion 30, each having the curvature radii r ₂₉ , r ₃₀ as described above, are the center side edges of the both side concave curved surface portions 29, 29. And the both side edges 30 of the central concave curved surface portion share a tangent line with each other so that they are smoothly continuous.

The outer ring 18a and the trunnion 9a are combined in a state in which the support beam portion 15 on the trunnion 9a side is fitted in the recess 19a on the outer ring 18a side. In such a combined state, the cylindrical convex surface 14 of the support beam portion 15 and the both side concave curved surface portions 29 and 29 abut at two positions in the circumferential direction of the support beam portion 15. The central angle θ relating to both the abutting portions can be arbitrarily adjusted based on the ratio of the respective curvature radii r ₂₉ , r ₃₀ and r ₁₄ . As the central angle θ increases, the effect of preventing the outer ring 18a from elastically deforming as shown in FIG. However, the greater the central angle θ, the greater the force applied in the direction of widening the gap between the both side concave curved surface portions 29, 29, and the greater the tensile stress applied to the bottom of the recess 19a or the vicinity thereof. . Conversely, the smaller the central angle θ, the smaller the force applied in the direction of widening the gap between the both side concave curved surface portions 29, 29, and the smaller the tensile stress applied to the bottom portion of the concave portion 19a or the vicinity thereof. . However, the smaller the central angle θ, the smaller the effect of preventing the outer ring 18a from elastically deforming as shown in FIG. Therefore, the central angle θ is appropriately regulated within a range in which the elastic deformation of the outer ring 18a is suppressed and the tensile stress applied to the bottom portion of the concave portion 19a or the vicinity thereof is not excessive. Specifically, the ratios of the respective radii of curvature r ₂₉ , r ₃₀ , r ₁₄ are determined so that the central angle θ falls within the range of 90 ° ± 30 °.

According to the structure of the present example configured as described above, a toroidal continuously variable transmission having sufficient durability can be realized.
That is, in the case of the toroidal continuously variable transmission according to the present invention, the inner surface of the recess 19a formed on the outer surface of the outer ring 18a constituting the thrust ball bearing 17a and the cylindrical convex surface 14 provided on the support beam portion 15. Are brought into contact with each other at two positions in the circumferential direction of both surfaces. For this reason, the contact area of the inner surface of the concave portion 19a and the cylindrical convex surface 14 can be secured, the surface pressure of the contact portions on both surfaces can be kept low, and the wear on both surfaces can be suppressed.

  Also, since the inner surface of the concave portion 19a and the cylindrical convex surface 14 are brought into contact with each other at two positions separated in the circumferential direction of the support beam portion 15, a large thrust load is applied to the outer ring 18a. In addition, the outer ring 18a can be prevented from being elastically deformed so that the inner side becomes a convex cylindrical surface as shown in FIG. 11B. In other words, the height of the inner surface of the outer ring 18a can be kept unchanged in the circumferential direction. Accordingly, the distance between the outer ring raceway 28 provided on the inner side surface of the outer ring 18a and the inner ring raceway 27 provided on the outer side surface of the power roller 8a is substantially constant with respect to the circumferential direction of the both raceways 28 and 27. Yes (to reduce the degree of disparity) For this reason, it can prevent that the surface pressure of the rolling contact part of both the said tracks 28 and 27 and the rolling surface of each ball | bowl 26 and 26 becomes partially excessive. As a result, it is possible to ensure the durability of the thrust ball bearing 17a, and hence the durability of the toroidal type continuously variable transmission incorporating the thrust ball bearing 17a.

  Furthermore, in the case of the structure of this example, the center side edges of the both side concave curved surface portions 29, 29 and the both side edges of the central concave curved surface portion 30 are smoothly continuous. Even when a large force in the direction away from each other is applied between the both side concave curved surface portions 29, 29 due to the pressing with the cylindrical convex surface 14, a tensile stress applied to the bottom portion of the concave portion 19a or the vicinity thereof is applied. Can be reduced. As a result, it is possible to prevent the outer ring 18a from being damaged such as a crack. Further, by providing the central concave curved surface portion 30, the central angle θ can be increased when the damage prevention performance of the outer ring 18a is the same as the tensile stress applied to the bottom of the concave portion 19a or the vicinity thereof can be reduced. It becomes possible to do. And the effect which suppresses the elastic deformation of the said outer ring | wheel 18a can be enlarged by enlarging this center angle (theta).

DESCRIPTION OF SYMBOLS 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 Power roller 9, 9a Trunnion 10, 10a Support shaft 11 Drive shaft 12 Press device DESCRIPTION OF SYMBOLS 13 Inclination shaft 14 Cylindrical convex surface 15 Support beam part 16 Radial needle bearing 17, 17a Thrust ball bearing 18, 18a Outer ring 19, 19a Concave part 20 Radial needle bearing 21 Downstream oil supply path 22 Upstream oil supply path 23 Oil supply pipe 24 Pulley 25 Stepped surface 26 Ball 27 Inner ring track 28 Outer ring track 29 Side concave curved surface portion 30 Central concave curved surface portion 31 Concave hole

Claims (2)

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 so as to be freely rotatable relative to each other, and 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. With rollers,
Each trunnion exists between the pair of tilting shafts concentrically provided at both ends and between the two tilting shafts, and at least the inner side surfaces in the radial direction of the two disks A support beam portion having a cylindrical convex surface, having a central axis that is parallel to the central axis of the tilting axis and is present outside the central axis of the tilting axis with respect to the radial direction of the two disks.
Each thrust rolling bearing is provided between the support beam portion and the outer surface of each power roller, and is provided on the outer ring provided on the support beam portion side and on the inner side surface of the outer ring. A plurality of rolling elements provided between the outer ring raceway and the inner ring raceway provided on the outer side surface of the power roller, the outer ring is provided on the outer side surface of the outer ring. A toroidal continuously variable transmission that is supported so as to be capable of swinging displacement in the axial direction of the two discs with respect to each trunnion by engaging the provided concave portion with the cylindrical convex surface of the support beam portion. However, the recesses provided on the outer side surface of the outer ring are provided on both sides in the width direction, and have a pair of side concave curved surface portions in which the curvature radius of the cross-sectional shape is larger than the curvature radius of the cylindrical convex surface. Having a Gothic arch-like cross-sectional shape There, a cylindrical convex surface of the recess and the support beam portion provided on the outer surface of the outer ring, the toroidal type continuously variable transmission, characterized in that in contact with the both sides concave portions.   There is a central concave curved surface portion between the concave concave surface portions on both sides where the radius of curvature of the cross-sectional shape is smaller than the radius of curvature of the cylindrical convex surface. The toroidal continuously variable transmission according to claim 1, wherein both side edges are smoothly continuous.

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