JP2005172022A - Toroidal continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure stable operation of a toroidal continuously variable transmission by preventing the wear and damage of a disc spring for imparting preload between a power roller and each disc and an input shaft or other portions for receiving the disc spring to improve the durability of thses components. <P>SOLUTION: The toroidal continuously variable transmission comprises the input side disc 2 and the output side disc 3 supported concentrically and rotatably with their inside faces being opposed to each other, the plurality of power rollers 11 held between the input side disc 2 and the output side disc 3, and the disc spring 8A for pushing outer peripheral faces 11a of the plurality of power rollers 11 against the inside faces 2a, 3a of the input side disc 2 and the output side disc 3. On the inner peripheral face and/or the outer peripheral face of the disc spring 8A, a circular face 40 is formed at an angled portion abutting on the outside, hardly causing stress concentration on a contact portion between the disc spring 8A and the outside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toroidal continuously variable transmission used as a transmission of, for example, automobiles and various industrial machines.

For example, a double-cavity toroidal continuously variable transmission used as a transmission for an automobile is configured as shown in FIGS.
As shown in FIG. 7, an input shaft (center shaft) 1 is rotatably supported inside the casing 50, and two input side disks 2, 2 and two outputs are provided on the outer periphery of the input shaft 1. Side disks 3 and 3 are attached. An output gear 4 is rotatably supported on the outer periphery of the intermediate portion of the input shaft 1. Output side disks 3 and 3 are connected to cylindrical flange portions 4a and 4a provided at the center of the output gear 4 by spline coupling.

  The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between an input side disk 2 and a cam plate 7 located on the left side in the drawing. . The output gear 4 is supported in the casing 50 via a partition wall 13 formed by coupling two members, so that the output gear 4 can rotate around the axis O of the input shaft 1 while the axis O. Directional displacement is prevented.

The output side disks 3 and 3 are supported by needle bearings 5 and 5 interposed between the input shaft 1 so as to be rotatable about the axis O of the input shaft 1.
Further, the left input side disk 2 in the figure is supported on the input shaft 1 via a ball spline 6, and the right side input disk 2 in the figure is splined to the input shaft 1. Rotates together with the input shaft 1. Further, the power roller 11 (see FIG. 8) is freely rotatable between the inner side surfaces (concave surfaces) 2a, 2a of the input side discs 2, 2 and the inner side surfaces (concave surfaces) 3a, 3a of the output side discs 3, 3. Is sandwiched between.

  A step 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 7, and the step 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step 2b. At the same time, the back surface (the right surface in FIG. 7) of the input side disk 2 is abutted against the loading nut 9. Thereby, the displacement of the input side disk 2 in the direction of the axis O with respect to the input shaft 1 is substantially prevented. Further, a disc spring 8 is provided between the cam plate 7 and the flange 1d of the input shaft 1, and this disc spring 8 is a concave surface 2a, 2a, 3a of each disk 2, 2, 3, 3. , 3a and a pressing portion (preload) is applied to a contact portion between the peripheral surfaces 11a and 11a of the power rollers 11 and 11.

  As shown in FIG. 9, the disc spring 8 is in contact with the cam plate 7 via a thrust needle bearing 10, while the flange 1 d of the input shaft 1 is in direct contact with the inner corner thereof. ing. The portion where the input shaft 1 and the flange portion 1d intersect is stressed particularly when high torque is transmitted. Therefore, a so-called corner radius portion 1e, which is a portion where the corner portion is rounded, is formed. Yes.

8 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 8, a pair of trunnions 15, 15 that swing about a pair of pivots 14, 14 that are twisted with respect to the input shaft 1 are provided inside the casing 50. In addition, illustration of the input shaft 1 is abbreviate | omitted in FIG.
Each trunnion 15, 15 is a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 8) of the support plate portion 16 so as to be bent toward the inner surface side of the support plate portion 16. have. The bent wall portions 20 and 20 form concave pocket portions P for accommodating the power rollers 11 in the trunnions 15 and 15. Further, the pivot shafts 14 and 14 are concentrically provided on the outer side surfaces of the bent wall portions 20 and 20, respectively.

  A circular hole 21 is formed in the central portion of the support plate portion 16, and the base end portion 23 a of the displacement shaft 23 is supported in the circular hole 21. Then, by swinging each trunnion 15, 15 about each pivot 14, 14, the inclination angle of the displacement shaft 23 supported at the center of each trunnion 15, 15 can be adjusted. Each power roller 11 is rotatably supported around the distal end portion 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15, and each power roller 11, 11 is connected to each input side disk. 2 and 2 and between the output side disks 3 and 3. In addition, the base end part 23a and the front-end | tip part 23b of each displacement shaft 23 and 23 are mutually eccentric.

  The pivot shafts 14 and 14 of the trunnions 15 and 15 are supported so as to be swingable and axially displaceable with respect to the pair of yokes 23A and 23B (back and front directions in FIG. 7 and up and down directions in FIG. 8). The trunnions 15 and 15 are restricted from moving in the horizontal direction by the yokes 23A and 23B.

Each yoke 23A, 23B is formed in a rectangular shape by pressing or forging a metal such as steel. Four circular support holes 18 are provided at the four corners of each of the yokes 23 </ b> A and 23 </ b> B, and the pivot shafts 14 provided at both ends of the trunnion 15 swing through the radial needle bearings 30. It is supported freely.
Further, a circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (the left-right direction in FIG. 8). 64 and 68 are fitted inside. That is, the upper yoke 23A is swingably supported by the spherical post 64 supported by the casing 50 via the fixing member 52, and the lower yoke 23A is composed of the spherical post 68 and the cylinder that supports the same. 31 is supported by the upper valve body 61 so as to be swingable.

  The displacement shafts 23 and 23 provided in the trunnions 15 and 15 are provided at positions 180 degrees opposite to the input shaft 1. Further, the direction in which the distal end portion 23b of each of the displacement shafts 23 and 23 is eccentric with respect to the base end portion 23a is the same direction as the rotational direction of both the disks 2, 2, 4 and 4 (up and down in FIG. 8). (Reverse direction). Further, the eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 1 is disposed. Accordingly, the power rollers 11 and 11 are supported so that they can be slightly displaced in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component member based on the thrust load generated by the pressing device 12, each component This displacement is absorbed without applying an excessive force to the member.

  Further, between the outer surface of the power roller 11 and the inner surface of the support plate portion 16 of the trunnion 15, a thrust ball bearing 24 that is a thrust rolling bearing, and a thrust needle bearing, in order from the outer surface side of the power roller 11. 25. Among these, the thrust ball bearing 24 supports the rotation of each power roller 11 while supporting the load in the thrust direction applied to each power roller 11. Each of the thrust ball bearings 24 is composed of a plurality of balls 26, 26, an annular retainer 27 for holding the balls 26, 26 in a freely rolling manner, and an annular outer ring 28. ing. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface of each power roller 11, and the outer ring raceway is formed on the inner side surface of each outer ring 28.

  The thrust needle bearing 25 is sandwiched between the inner surface of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. Such a thrust needle bearing 25 supports the thrust load applied to each outer ring 28 from the power roller 11, while the power roller 11 and the outer ring 28 swing around the base end portion 23 a of each displacement shaft 23. Allow.

  Further, driving rods (trunnion shafts) 29 and 29 are provided at one end portions (lower end portions in FIG. 8) of the trunnions 15 and 15, respectively, and a driving piston ( Hydraulic pistons) 33, 33 are fixed. Each of these drive pistons 33 and 33 is oil-tightly fitted in a drive cylinder 31 constituted by an upper valve body 61 and a lower valve body 62. The drive pistons 33 and 33 and the drive cylinder 31 constitute a drive device 32 that displaces the trunnions 15 and 15 in the axial direction of the pivots 14 and 14 of the trunnions 15 and 15.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 1 is transmitted to the input side disks 2 and 2 via the pressing device 12. Then, the rotation of the input side disks 2 and 2 is transmitted to the output side disks 3 and 3 via the pair of power rollers 11 and 11, and the rotation of the output side disks 3 and 3 is further transmitted to the output gear 4. Is taken out more.

  When changing the rotational speed ratio between the input shaft 1 and the output gear 4, the pair of drive pistons 33, 33 are displaced in opposite directions. As the drive pistons 33 and 33 are displaced, the pair of trunnions 15 and 15 are displaced in directions opposite to each other. For example, the power roller 11 on the left side in FIG. 8 is displaced to the lower side in the figure, and the power roller 11 on the right side in the figure is displaced to the upper side in the figure. As a result, the peripheral surfaces 11a and 11a of the power rollers 11 and 11 act on contact portions of the input side disks 2 and 2 and the inner side surfaces 2a, 2a, 3a and 3a of the output side disks 3 and 3, respectively. The direction of the tangential force changes. As the force changes, the trunnions 15 and 15 swing in opposite directions around the pivots 14 and 14 pivotally supported by the yokes 23A and 23B.

  As a result, the contact position between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 3a changes, and the rotational speed ratio between the input shaft 1 and the output gear 4 changes. Further, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11 and 11 and the outer rings attached to the power rollers 11 and 11 will be described. 28 and 28 slightly rotate around the base end portions 23a and 23a of the displacement shafts 23 and 23, respectively. Since the thrust needle bearings 25 and 25 exist between the outer side surfaces of the outer rings 28 and 28 and the inner side surfaces of the support plate portions 16 constituting the trunnions 15 and 15, respectively, the rotation is performed smoothly. Is called. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 23, 23 can be small.

  In the toroidal-type continuously variable transmission configured as described above, it is necessary to ensure smooth operation of the sliding portion accompanying relative movement between the constituent members, and if foreign matter is generated in such a sliding portion. The contact surface (traction surface) between the power rollers 11 and 11 and the two disks 2 and 3 causes indentation and surface peeling due to biting, thereby shortening the service life. Therefore, various devices have been made in addition to supplying lubricating oil to these parts. For example, Patent Document 1 describes that a surface that receives a disc spring for applying a preload between the power rollers 11 and 11 and both the disks 2 and 3 is heat-treated and cured.

JP 2002-89647 A

  In the toroidal type continuously variable transmission configured as described above, the load applied to the disc spring also changes as the transmission torque changes, and the disc spring repeatedly expands and contracts. At this time, a pressing force of several tons is applied to the disc spring, so that the disc spring itself, the flange of the input shaft that receives the disc spring, and the surface of the thrust needle bearing are likely to be worn or damaged. When the disc spring is worn, the thrust of the disc spring decreases, and it becomes impossible to generate an appropriate pressing force particularly at a low torque. On the other hand, scratches and wear on the flange portion on the input shaft side cause a decrease in strength of the input shaft.

  Also, the disc spring's inner diameter corner that is in contact with the corner radius of the input shaft's outer diameter and flange surface is not chamfered or curved, so the disc spring's corner is subject to wear and input Damage to the rounded corners of the shaft is also likely to occur. If the input shaft is worn, the strength may be reduced and the input shaft may be damaged. Furthermore, when foreign matter generated due to wear of the disc spring and the input shaft adheres to the traction surface, indentation, peeling, etc. are likely to occur on the disk and power roller surfaces, leading to a reduction in life.

  Therefore, the present invention improves the durability of these parts by preventing wear and scratches on the disc spring that applies preload between the power roller and both discs, and the input shaft that receives the disc spring or other parts. Therefore, an object is to ensure a stable operation of the toroidal type continuously variable transmission.

  In order to achieve the object, the toroidal continuously variable transmission according to claim 1 includes an input side disk and an output side that are concentrically and rotatably supported with their inner side surfaces facing each other. A disc, a plurality of power rollers sandwiched between the input side disc and the output side disc, and a disc spring for pressing the outer peripheral surfaces of the plurality of power rollers against the inner side surfaces of the input side disc and the output side disc In the toroidal type continuously variable transmission provided with the above-mentioned structure, the inner peripheral surface and / or the outer peripheral surface of the disc spring is formed with a circular arc surface at a corner contacting the outside.

  A toroidal continuously variable transmission according to a second aspect of the present invention is the invention according to the first aspect, wherein the corner portion is in contact with a flange portion formed on a shaft body, and the curvature of the arc surface is equal to that of the flange portion. It is characterized by being set larger than the radius of curvature of the corner rounded portion formed at the base.

  According to the first aspect of the present invention, since the arc surface is formed at the corner of the end face of the disc spring, even if both slide with each other during the operation of the device, the stress concentration at these contact portions Is unlikely to occur. Therefore, both the corner portion of the disc spring itself and the spring receiving member that contacts the disc spring are prevented from being worn or damaged by friction. Therefore, the action of the disc spring that presses the outer peripheral surface of the power roller against the inner surface of the input side disc and the output side disc is kept stable, and wear and scratches on the input shaft receiving the disc spring are also prevented. Thus, efficient and stable operation of the toroidal continuously variable transmission is maintained. In addition, since the generation of foreign matter due to wear can be prevented, it is also possible to prevent foreign matter from adhering to and scratching the inner surface of the input side disk and output side disc and the outer peripheral surface of the power roller. A stable operation of the apparatus can be achieved.

  According to the second aspect of the present invention, since the curvature of the arc surface is set larger than the curvature radius of the corner radius portion formed at the base of the flange portion, the arc surface of the disc spring contacts the corner radius portion. Is prevented. Therefore, it is possible to prevent the corner radius portion where stress is easily concentrated during power transmission from being worn or damaged by friction, and to extend the life.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a toroidal-type continuously variable transmission according to an embodiment of the present invention. The basic configuration and function of this embodiment are the same as those in FIGS. 7 to 8 described above, the step 2b on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. ) Since it is the same except that there is no step portion 1b provided on the outer peripheral surface 1a, the same reference numerals are given to the respective constituent elements and the description thereof is omitted.

  FIG. 2 shows the structure of the disc spring 8A, which is the main part of the present invention, and the structure of the portion that accommodates it. The base portion of the flange portion 1d of the input shaft 1 has a concave arc-shaped corner as in the prior art. A rounded portion 1e is formed. On the other hand, as is well known, the disc spring 8A is an umbrella-shaped annular member having a hole formed in the center, and the positions of the inner peripheral surface and the outer peripheral surface slightly shifted in the axial direction. In this embodiment, four sheets are used in combination by overlapping two sheets in the same direction and butting the large diameter side. Arc surfaces 40 are formed at the corners on the small diameter side of the inner peripheral surface and the large diameter side of the outer peripheral surface of each disc spring 8A (only the inner diameter side is shown in the figure). The arc surface 40 may be formed by plastic working when manufacturing the disc spring 8A or by chamfering after manufacturing.

  In this embodiment, the radius of curvature (R2) of the arc surface 40 of the disc spring 8A is set to be larger than the radius of curvature (R1) of the corner radius portion 1e of the base portion of the flange 1d (R2> R1). ). Therefore, the disc spring 8A always comes into contact with the flat surface of the flange 1d, not the corner radius 1e (FIG. 2). Accordingly, the corner radius portion 1e where stress concentration is likely to occur is prevented from being damaged by the contact of the disc spring 8A and the friction accompanying the operation of the apparatus, and accidents such as breakage of the input shaft 1 can be reduced.

In this embodiment, the arcuate surface 40 is formed on the corners on the small diameter side of the inner peripheral surface and the large diameter side of the outer peripheral surface in all four disc springs 8A. That is, if the circular arc surface 40 is formed only at the corners on the small diameter side of the inner peripheral surface of the disc spring 8A at both ends in the axial direction, the purpose of alleviating stress concentration at the contact portion can be achieved.
Further, when the radius of curvature (R2) of the circular arc surface 40 of the disc spring 8A is set to be twice or more of the radius of curvature (R1) on the corner radius portion 1e side, the number of contact points becomes two points, which is further effective in preventing wear. The following values are recommended as examples of dimensions.
R2: 1mm to 2mm
R1: 0.5 mm to 1 mm
This is because the thickness of the disc spring is often about 2 mm to 4 mm due to its function, and about 1/2 of that is the radius of curvature.

FIG. 3 shows another embodiment of the present invention, in which the radius of curvature (R2) of the arc surface 40 is set smaller than the radius of curvature (R1) of the corner radius portion 1e (R1> R2). In this case, the difference between the inner diameter (D1) of the disc spring 8A and the outer diameter (D2) of the input shaft is smaller than twice the radius of curvature (R1) of the corner radius portion 1e.
(D1-D2) / 2 <R1
When this is the case, the inner end portion of the disc spring 8A is in contact with the corner radius portion 1e. Even in this case, since the circular arc surface 40 is formed at the inner end portion of the disc spring 8A, the stress concentration at the contact portion is prevented, and the occurrence of wear, delamination and the like at both is prevented or reduced.

  4 (a) and 4 (b) show another embodiment of the present invention. In the previous embodiment, a smooth curved surface was formed by molding the end of the disc spring 8A. However, in this embodiment, an arc is formed by bending the end (edge) of the disc spring 8B. A surface 40 is formed. FIG. 4A shows a case where the radius of curvature (R2) of the arc surface 40 is set larger than the radius of curvature (R1) of the corner radius portion 1e (R2> R1), and corresponds to FIG. FIG. 4B shows a case where the radius of curvature (R2) of the arc surface 40 is set smaller than the radius of curvature (R1) of the corner radius portion 1e (R1> R2), and corresponds to FIG. Needless to say, these embodiments also exhibit the same operations and effects as the previous embodiments.

  5 and 6 show another embodiment of the present invention. In the previous embodiment, the disc springs 8A and 8B are formed on the input shaft 1 on the same side as the loading cam type pressing device 12 with respect to the input side disks 2 and 2 and the output side disks 3 and 3, respectively. It was provided so as to be in contact with the flange 1d. On the other hand, in this embodiment, the disc spring 8C is in contact with the loading nut 9 fixed to the input shaft 1 on the side opposite to the pressing device 12 with respect to the input side disks 2 and 2 and the output side disks 3 and 3. Is attached. In this embodiment, the radius of curvature (R2) of the arc surface 40 is set to be smaller than the radius of curvature (R1) of the corner radius portion 1e at the base of the loading nut 9 (R1> R2), but the reverse case (R2> R1) may be sufficient. It goes without saying that this embodiment also has the same operations and effects as the previous embodiment.

In addition, although this invention was used for the disc spring provided in the mechanical type press, it can be used similarly about the disc spring provided in the cylinder of the hydraulic press.
Although the present invention has been described in the case of a half-toroidal continuously variable transmission, it can also be used in a full-toroidal continuously variable transmission.

1 is a longitudinal sectional view of a toroidal continuously variable transmission according to an embodiment of the present invention. It is a figure which expands and shows the principal part of FIG. It is a figure which expands and shows the principal part of other embodiment of this invention. (A), (b) is a figure which expands and shows the principal part of other embodiment of this invention. It is a figure which shows the cross section of the principal part of further another embodiment of this invention. It is a figure which expands and shows the principal part of FIG. It is a longitudinal cross-sectional view of the conventional toroidal type continuously variable transmission. It is sectional drawing along the AA line of FIG. It is a figure which expands and shows the principal part of FIG.

Explanation of symbols

1 Input shaft (shaft body)
1d collar portion 1e corner radius portion 2 input side disk 2a inner side surface 3 output side disk 3a inner side surface 8A, 8B, 8C disc spring 11 power roller 11a outer peripheral surface 14 pivot 15 trunnion 40 arc surface R1 radius of curvature R2 arc Radius of curvature of face

Claims (2)

An input-side disk and an output-side disk that are concentrically and rotatably supported with their inner surfaces facing each other, and a plurality of power rollers sandwiched between the input-side disk and the output-side disk, A toroidal continuously variable transmission comprising a disc spring that presses the outer peripheral surfaces of the plurality of power rollers against the inner surfaces of the input side disk and the output side disk;
A toroidal-type continuously variable transmission characterized in that an arc surface is formed at a corner portion in contact with the outside on an inner peripheral surface and / or an outer peripheral surface of the disc spring.   The corner is in contact with a flange formed on the shaft body, and the curvature of the arc surface is set larger than the radius of curvature of the corner radius formed at the base of the flange. Item 2. The toroidal continuously variable transmission according to item 1.

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