JP2008002599A - Toroidal type stepless speed change device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toroidal type stepless speed change device in which loading nut can be fastened with input shaft threaded portion strength enhanced. <P>SOLUTION: In the toroidal type stepless speed change device, a core diameter D of a nut engaging portion 1d of the input shaft 1 is set larger than an outer diameter d of a disc supporting portion 1f. Therefore, the strength of the threaded portion 200 of the nut engaging portion 1d becomes higher than that of conventional one, allowing the strength of the input shaft 1 at this position to be increased. Besides, thrust load generated by a pressing device 300 is supported by cotter 250 at the opposite side of the loading nut 9 and hence guarantee against stress can be easily fulfilled as compared to the case of supporting the thrust load by a screw. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toroidal continuously variable transmission that can be used for transmissions of 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. 2, the input shaft 1 is rotatably supported inside the casing 50, and two input side disks 2, 2 and two output side disks 3 are disposed on the outer periphery of the input shaft 1. 3 is 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 driven to rotate by a drive shaft 22 via a loading cam type pressing device 12 provided between an input side disk 2 and a cam plate (loading cam) 7 located on the left side in the drawing. It has become. The output gear 4 is supported on a partition wall (intermediate wall) 13 formed by coupling two members via an angular ball bearing 107 and is supported in the casing 50 via the partition wall 13. Thus, while being able to rotate around the axis O of the input shaft 1, displacement in the direction of the axis O 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. , 2 rotate together with the input shaft 1. A power roller is provided between the inner side surfaces (concave surface; also referred to as a traction surface) 2a and 2a of the input side disks 2 and 2 and the inner side surfaces (concave surface; also referred to as a traction surface) 3a and 3a of the output disks 3 and 3. 11 (see FIG. 3) is rotatably held.

  A step 2b is provided on the inner peripheral surface 2c of the input disk 2 located on the right side in FIG. 2, 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 (right surface in FIG. 2) of the input side disk 2 is abutted against a loading nut 9 screwed into a threaded portion formed on the outer peripheral surface of the input shaft 1. 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 the contact surface between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 are applied with a pressing force.

  As shown in FIG. 3 which is a cross-sectional view taken along the line AA of FIG. 2, both the disks 3 and 3 are sandwiched from both sides inside the casing 50 and at the side positions of the output side disks 3 and 3. The pair of yokes 23A and 23B is supported in the state. The pair of yokes 23A and 23B are formed in a rectangular shape by pressing or forging a metal such as steel. In order to support pivots 14 provided at both ends of the trunnion 15 to be described later in a swingable manner, circular support holes 18 are provided at the four corners of the yokes 23A and 23B, and the width direction of the yokes 23A and 23B. A circular locking hole 19 is provided at the center of the.

  The pair of yokes 23A and 23B is supported by support posts 64 and 68 formed on the inner surface of the casing 50 so as to be able to swing around the support posts 64 and 68 as fulcrums. These support posts 64 and 68 are provided so as to face the first cavity 221 and the second cavity 222, respectively, between the inner side surface 2a of the input side disk 2 and the inner side surface 3a of the output side disk 3. Yes.

  Therefore, the yokes 23 </ b> A and 23 </ b> B are supported by the support posts 64 and 68, and one end thereof faces the outer peripheral portion of the first cavity 221, and the other end faces the outer peripheral portion of the second cavity 222. is doing.

  Since the first and second cavities 221 and 222 have the same structure, only the first cavity 221 will be described below.

  As shown in FIG. 3, inside the casing 50, the first cavity 221 is provided with 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. It has been. In FIG. 3, the input shaft 1 is not shown. Each trunnion 15, 15 is a pair of bent portions formed in a state in which the trunnions 15, 15 are bent toward the inner side surface of the support plate 16 at both ends in the longitudinal direction (vertical direction in FIG. 3) of the support plate 16. Wall portions 20 and 20 are provided. 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 center portion of the support plate portion 16, and a base end portion (first shaft 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. In addition, each power roller 11 is rotatably supported around the tip end portion (second shaft portion) 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15. 11 is sandwiched between the input disks 2 and 2 and the output 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.

  Further, as described above, the pivot shafts 14 and 14 of the trunnions 15 and 15 are supported so as to be swingable with respect to the pair of yokes 23A and 23B and to be displaceable in the axial direction (vertical direction in FIG. 3). The trunnions 15 and 15 are restricted from moving in the horizontal direction by the yokes 23A and 23B. As described above, four circular support holes 18 are provided at the four corners of each of the yokes 23A and 23B, and the pivot shafts 14 provided at both ends of the trunnion 15 are respectively provided in the support holes 18 with radial needle bearings ( A tilting bearing 30 is supported so as to be swingable (tiltable). Further, as described above, the circular locking hole 19 is provided in the central portion of the yokes 23A and 23B in the width direction (left and right direction in FIG. 3), and the inner peripheral surface of the locking hole 19 is cylindrical. Support posts 64 and 68 are internally fitted as surfaces. 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 23B is supported by the spherical post 68 and the drive for supporting the same. The upper cylinder body 61 of the cylinder 31 is swingably supported.

  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, 3 and 3 (up and down in FIG. 3). (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 (large end 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 (shaft portions extending from the pivot shaft) 29 and 29 are respectively provided at one end portions (lower end portions in FIG. 3) of the trunnions 15 and 15, and outer peripheral surfaces of intermediate portions of the driving rods 29 and 29. The drive pistons (hydraulic pistons) 33, 33 are fixedly provided. Each of these drive pistons 33 and 33 is oil-tightly fitted in a drive cylinder 31 constituted by an upper cylinder body 61 and a lower cylinder 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 drive shaft 22 is transmitted to the input side disks 2 and 2 and the input shaft 1 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. It 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 of FIG. 3 is displaced downward in the figure, and the power roller 11 on the right side of FIG. 3 is displaced upward 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.

  By the way, in the toroidal type continuously variable transmission having the above-described configuration, the portion of the input shaft 1 on the side opposite to the side on which the loading nut 9 is attached is thick. It has become. That is, the following description will be given by taking as an example the further conventional structure shown in FIG. 4 (the same components as those in FIGS. 2 and 3 are denoted by the same reference numerals and description thereof will be omitted). Each of the pair of output side disks 3 is coupled to the output gear 4 at the center of the input shaft 1 so as to face the corresponding input side disk 2 and is supported by the casing 50 via the partition wall 13. Has been. The input shaft 1 has a flange 1d as a first end to which rotational torque is input and a second end 1e positioned on the opposite side, and the first and second ends. It is supported by bearings 100 and 101 disposed in the portions 1d and 1e and bearings 5 and 5 disposed in the center between the first and second end portions 1d and 1e. An angular ball bearing 190 that can support a thrust load is interposed between the flange 1d of the input shaft 1 and the cam plate 7. Further, a first disc spring 8 is provided between the input side disk 2 and the cam plate 7 located on the left side in the drawing adjacent to the flange (first end) 1d, and the second end 1e. A second disc spring 10 is provided between the input side disk 2 located on the right side in the drawing and the loading nut 9. These disc springs 8 and 10 are preloaded in contact portions between the concave surfaces 2a, 2a, 3a and 3a of the disks 2, 2, 3 and 3 and the peripheral surfaces (traction surfaces) 11a and 11a of the power rollers 11 and 11, respectively. Is granted.

  As described above, in the structure of FIG. 4 including the conventional structure shown in FIGS. 2 and 3, the first end on the opposite side of the second end 1e of the input shaft 1 to which the loading nut 9 is attached is also provided. Since the outer diameter of the end 1d is large, it is necessary to attach the disks 2 and 3 from the second end 1e on the side where the loading nut 9 is attached. Therefore, at least the outer diameter of the thread portion 1g of the input shaft 1 to which the loading nut 9 is screwed needs to be smaller than the inner diameter of the disks 2 and 3. On the other hand, it is necessary to generate a surface pressure of about 1 GPa between the disks 2 and 3 and the power roller 11 in order to perform the traction drive even when there is no load. As a result, the loading nut 9 at the thread portion 1g is required. A very large axial force is generated by tightening. That is, it is necessary to generate a large axial force with the thin screw portion 1g, but it is desirable to improve this to increase the strength of the screw portion of the input shaft 1.

  Further, the input shaft 1 is carburized to increase the surface hardness in order to make itself the raceway surface of the bearings 5 and 5 and to transmit a large force. On the contrary, the threaded portion 1g is brittle by carburizing. Will increase. Therefore, although the carburizing agent is applied to the thread portion 1g, the application of the carburizing agent may not be sufficient or may not be applied uniformly, and labor is required to keep the quality constant. There is also a method of machining the screw after adding extra meat to the threaded portion 1g and then removing the carburized layer, but removing the carburized layer is not easy and increases the manufacturing cost. .

  In relation to this, Patent Document 1 attempts to solve the above problem by using a cotter as a fixing member. Even when such a cotter is used, the input shaft 1 is cut into a locking groove (cotter groove), so that the outer diameter of the input shaft 1 becomes thin. However, the screw bottom has a shape close to a V-shaped notch. On the other hand, since the cotter groove is not such a shape, stress concentration is less likely to occur compared to the threaded portion. Therefore, it becomes easy to guarantee against stress.

JP 2000-205361 A

  However, even when a cotter is used as disclosed in Patent Document 1, the problem of the reduction in the diameter of the threaded portion 1g and the accompanying shaft strength (stress concentration) is insufficient, and the disc spring 8, Since the annular part must be inserted into the locking groove against the force of 10, there is a problem that the assembly process becomes complicated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a toroidal continuously variable transmission that can fasten a loading nut while increasing the strength of a threaded portion of an input shaft.

  To achieve the above object, the toroidal continuously variable transmission according to claim 1 rotates concentrically and with an input shaft to which rotational torque is input and respective inner surfaces facing each other. An input disk and an output disk supported by the input shaft freely, a plurality of power rollers sandwiched between the input disk and the output disk, the input / output disk, and the power roller A toroidal continuously variable transmission comprising: a pressing device that applies a predetermined pressing force between the input shaft; and a loading nut that is screwed to the input shaft and supports a thrust load generated by the pressing device. The shaft is screwed into the loading nut and a disk support portion that supports at least one of the input side disk and the output side disk. And a nut threaded portion Flip portion is formed, the diameter of the thread root of the nut screwed part being greater than the outer diameter of the disc supporting portion.

  In the first aspect of the invention, since the diameter of the screw bottom of the nut screwing portion of the input shaft is set larger than the outer diameter of the disk support portion, the strength of the screw portion of the nut screwing portion is high. It is possible to increase the strength of the input shaft at this portion, and it is easy to guarantee stress concentration.

  According to a second aspect of the present invention, there is provided a toroidal continuously variable transmission according to the first aspect of the present invention, wherein the thrust load generated by the pressing device is applied to the input shaft on the opposite side of the loading nut. It is supported by a cotter locked in a stop groove.

  In the invention described in claim 2, since the thrust load generated by the pressing device is supported by the cotter locked in the locking groove of the input shaft on the opposite side of the loading nut, Compared to, it is easier to guarantee the stress. That is, even when a cotter is used, a cotter locking groove (cotter groove) is formed on the input shaft, so that the outer diameter of the input shaft is reduced by that amount, but the screw bottom is a V-shaped notch. Since the locking groove is not such a sharp shape in spite of the close shape, stress concentration is less likely to occur compared to the threaded portion, and therefore it is easy to guarantee the stress. In this configuration, if the cotter is attached before the loading nut is attached, the force of the preload spring that applies preload to the contact portion between each disk and the power roller does not work, so that assembly is facilitated.

  According to the toroidal type continuously variable transmission of the present invention, since the diameter of the screw bottom of the nut screwing portion of the input shaft is set larger than the outer diameter of the disc support portion, the strength of the screw portion of the input shaft is increased. The loading nut can be fastened.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the present invention lies in the structure of the input shaft, and other configurations and operations are the same as those of the conventional configuration and operations described above. Therefore, only the features of the present invention will be referred to below, and the rest These parts are simply described with the same reference numerals as those in FIGS.

  FIG. 1 shows an embodiment of the present invention. As shown in the figure, the input side disk 2 and the output side disk 3 are supported concentrically and rotatably on the input shaft 1 to which rotational torque is input, with the inner surfaces facing each other. Yes. Although the illustration is simplified, the integrated output side disk 3 is rotatably supported with respect to the input shaft 1 by a bearing interposed between the input shaft 1 and the left side in the figure. The input side disk 2 is supported on the input shaft 1 via a ball spline, and the input side disk 2 on the right side in the figure is splined to the input shaft 1, and these input side disks 2 and 2 are connected to the input shaft 1. It is designed to rotate with. Although not shown, a plurality of power rollers are sandwiched between the input side disk 2 and the output side disk 3.

  The input shaft 1 supports a first end 1d as a large-diameter collar part, a second end 1e as a small-diameter part located on the opposite side, an input side disk 2 and an output side disk 3. And a disk support portion 1f. Therefore, in the case of this configuration, the input side disk 2 and the output side disk 3 are assembled from the second end 1e side (attached to the input shaft 1).

  The first end portion 1d is provided as a nut screwing portion 1d in which a screw portion 200 is formed, and a loading nut 9 is screwed to the screw portion 200. A pressing device 300 is provided between the loading nut 9 and the input side disk 2 to apply a pressing force to the contact portion between each of the disks 2 and 3 and the power roller. As the pressing device 300, in addition to a mechanical pressing device such as a loading cam type, a hydraulic pressing device or the like can be used. The pressing device 300 is also provided with a preload spring for applying a preload to the contact portion between each of the disks 2 and 3 and the power roller. The pressing device 300 is screwed with the loading nut 9 to press the pressing device. By tightening 300, the elasticity of the preload spring can be adjusted to adjust the preload acting on the contact portion between each disk 2, 3 and the power roller. Note that the preload spring may be provided separately from the pressing device 300, and may be installed at another location, for example, between the cotter 259 and the input side disk 2 described later. It may be.

  In the present embodiment, the diameter D of the screw bottom of the nut screwing portion 1d is set to be larger than the outer diameter d of the disc support portion 1f. A cotter (locking ring) 250 is locked to a locking groove (cotter groove) 240 formed in the second end 1e of the input shaft. The cotter 250 and the loading nut 9 are disposed on both sides of the pressing device 300 and each of the disks 2 and 3 and the power roller, and regulate the axial displacement of the input shaft 1 of each of the disks 2 and 3 and the power roller. In addition, the thrust load generated by the pressing device 300 (the axial load of the input shaft 1) is supported.

  Thus, in this embodiment, since the diameter D of the screw bottom of the nut screwing portion 1d of the input shaft 1 is set larger than the outer diameter d of the disk support portion 1f, the screw portion of the nut screwing portion 1d. The strength of 200 is increased compared to the conventional case, and the strength of the input shaft 1 at this portion can be increased. In addition, it is easy to guarantee against stress concentration.

In the present embodiment, the thrust load generated by the pressing device 300 is supported by the cotter 250 locked to the locking groove 240 of the input shaft 1 on the opposite side of the loading nut 9. Compared to, it is easier to guarantee the stress. That is, even when the cotter 250 is used, since the cotter locking groove 240 is cut in the input shaft 1, the outer diameter of the input shaft 1 is reduced correspondingly, but the screw bottom is close to a V-shaped notch. The shape of the cotter groove 240 is not such a sharp shape (a concave groove having a rectangular cross section), but stress concentration is less likely to occur compared to the threaded portion, and therefore it is easy to guarantee the stress.
In this embodiment, if the cotter 250 is attached before the loading nut 9 is attached, the force of the preload spring does not work, so that assembly is facilitated.

  In the above-described embodiment, the disk support portion 1f of the input shaft 1 supports both the input side disks 2 and 2 and the output side disk 3. However, the disk support portion of the input shaft serves as the input side disk and the input side disk. One of the output side disks may be supported. For example, one of the input side disk and the output side disk may be supported on the casing via a bearing.

  In the above-described embodiment, the pressing device 300 is provided between the loading nut 9 and the left input side disk 2, but may be provided at another location, for example, the cotter 250 and the right input side disk. 2 may be provided.

  In the above-described embodiment, the axial displacement of the disks 2 and 3 and the input shaft 1 of the power roller on the opposite side of the loading nut 9 is restricted, and the thrust load (input) generated by the pressing device 300 is also controlled. The cotter 250 is used to support the load in the axial direction of the shaft 1, but another one may be used instead.

  The present invention can be applied to a full toroidal continuously variable transmission having no trunnion, in addition to various half toroidal continuously variable transmissions such as a single cavity type and a double cavity type.

It is sectional drawing which simplifies and shows the principal part of the toroidal type continuously variable transmission which concerns on embodiment of this invention. It is sectional drawing which shows an example of the specific structure of the toroidal type continuously variable transmission conventionally known. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which shows an example of the other specific structure of the toroidal type continuously variable transmission conventionally known.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 1d Nut screwing part 1f Disk support part 2 Input side disk 3 Output side disk 9 Loading nut 11 Power roller 240 Locking groove 250 Cotter 300 Pressing device

Claims (2)

An input shaft to which rotational torque is input, an input-side disk and an output-side disk supported on the input shaft so as to be concentrically and freely rotatable with their inner surfaces facing each other, and the input-side disk And a plurality of power rollers sandwiched between the output side disk, a pressing device that applies a predetermined pressing force between the input / output side disk and the power roller, and screwed to the input shaft And a toroidal continuously variable transmission provided with a loading nut for supporting a thrust load generated by the pressing device,
The input shaft includes a disk support portion that supports at least one of the input side disc and the output side disc, and a nut screwing portion in which a screw portion into which the loading nut is screwed is formed, and the nut A toroidal continuously variable transmission, wherein a diameter of a screw bottom of a screwing portion is larger than an outer diameter of the disk support portion.   2. The toroidal continuously variable transmission according to claim 1, wherein a thrust load generated by the pressing device is supported by a cotter locked in a locking groove of the input shaft on the opposite side of the loading nut. Machine.

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