JP6507489B2 - Toroidal type continuously variable transmission - Google Patents

Description

  The present invention relates to a toroidal continuously variable transmission that can be used as a transmission for automobiles and various industrial machines.

  For example, a double cavity type toroidal continuously variable transmission used as a transmission for an automobile is configured as shown in FIG. 4 and FIG. As shown in FIG. 4, the input shaft 1 (shaft) is rotatably supported inside the casing 50, and two input side disks 2 and 2 (second 1) and two output side disks 3, 3 (second disks) are attached. Further, an output gear 4 is rotatably supported on the outer periphery of the middle portion of the input shaft 1 (shaft). The output side disks 3 and 3 are connected to the cylindrical flanges 4a and 4a provided at the center of the output gear 4 by spline connection.

  The input shaft 1 (shaft) is rotationally driven by the drive shaft 22 via a loading cam type pressing device 12 provided between the input side disk 2 positioned on the left side in the drawing and the cam plate 7. It has become. In addition, the output gear 4 is supported in the casing 50 via a partition wall 13 formed by coupling of two members, whereby it can rotate around the axis O of the input shaft 1 (shaft). , Displacement in the direction of the axis O is prevented.

  The output side disks 3, 3 are rotatably supported centering on the axis O of the input shaft 1 (shaft) by needle bearings 5, 5 interposed between the output side disks 3 and 3 (input shaft 1). Further, the input side disc 2 on the left side in the figure is supported by the input shaft 1 (axis) via a ball spline 6, and the input side disc 2 on the right side in the figure is splined to the input axis 1 (axis) These input side disks 2 are designed to rotate with the input shaft 1 (shaft). In addition, the power roller 11 (see FIG. 5) is rotatable between the inner side surfaces (concave surfaces) 2a, 2a of the input side disks 2, 2 and the inner side surface (concave surface) 3a, 3a of the output side disks 3, 3. It is held by

  A step 2b is provided on the inner peripheral surface 2c of the input side disk 2 positioned on the right side in FIG. 4, and the step 1b provided on the outer peripheral surface 1a of the input shaft 1 (shaft) is provided on the step 2b. While being abutted, the rear surface (right surface in FIG. 4) of the input side disc 2 is abutted against the loading nut 9. Thereby, the displacement of the input disk 2 in the direction of the axis O with respect to the input shaft 1 (axis) is substantially prevented. Further, a disc spring 8 is provided between the cam plate 7 and the flange portion 1d of the input shaft 1 (shaft), and the disc spring 8 is a concave surface 2a of each of the disks 2, 2, 3 and 3. A pressing force is applied to the contact portion between 2a, 3a, 3a and the circumferential surfaces 11a, 11a of the power rollers 11, 11.

  FIG. 5 is a cross-sectional view taken along the line AA of FIG. As shown in FIG. 5, inside the casing 50, a pair of trunnions 15, 15 swinging around a pair of pivots 14, 14 at a position of torsion with respect to the input shaft 1 (shaft) are provided. . In FIG. 5, the illustration of the input shaft 1 (axis) is omitted. Each of the trunnions 15, 15 is a pair of bent wall portions 20, 20 formed at both end portions in the longitudinal direction (vertical direction in FIG. 5) of the support plate portion 16 so as to be bent toward the inner side surface of the support plate portion 16. have. A concave pocket portion P for accommodating the power roller 11 is formed in each of the trunnions 15, 15 by the bent wall portions 20, 20. The pivots 14 and 14 are provided concentrically with each other on the outer surface of each of the bent wall portions 20 and 20.

  A circular hole 21 is formed in the central portion of the support plate portion 16, and a base end (first shaft portion) 23 a of the displacement shaft 23 is supported by the circular hole 21. The tilt angles of the displacement shafts 23 supported at the central portions of the trunnions 15, 15 can be adjusted by swinging the trunnions 15, 15 about the pivots 14, 14, respectively. In addition, each power roller 11 is rotatably supported around the tip 23 b of the displacement shaft 23 protruding from the inner side surface of each trunnion 15, 15, and each power roller 11 is a disk on each input side 2, 2 and each output side disc 3, 3 are held. The proximal end 23a and the distal end 23b of each displacement shaft 23, 23 are eccentric to each other.

  The pivot shafts 14 and 14 of the trunnions 15 and 15 are respectively swingably supported on the pair of yokes 23A and 23B and displaceable in the axial direction (vertical direction in FIG. 5). The horizontal movement of trunnions 15, 15 is restricted by 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 23A and 23B, and pivot shafts 14 provided at both ends of the trunnion 15 are respectively pivoted through the radial needle bearings 30 in these support holes 18 It is freely supported. Further, a circular locking hole 19 is provided at the central portion in the width direction (left and right direction in FIG. 4) of the yokes 23A and 23B, and the inner peripheral surface of the locking hole 19 is a cylindrical surface. 64, 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 23B is a spherical post 68 and a drive for supporting the same. It is pivotally supported by the upper cylinder body 61 of the cylinder 31.

  The displacement shafts 23, 23 provided in the trunnions 15, 15 are provided at positions 180 degrees opposite to each other with respect to the input shaft 1 (shaft). Further, the direction in which the distal end portion 23b of each displacement shaft 23, 23 is eccentric with respect to the base end portion 23a is the same direction with respect to the rotation direction of both the disks 2, 2, 3 and 3 (in FIG. In the opposite direction). Moreover, the eccentric direction is a direction substantially orthogonal to the arrangement direction of the input shaft 1 (axis). Therefore, each power roller 11, 11 is supported so as to be slightly displaceable in the longitudinal direction of the input shaft 1 (shaft). As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 (axis) due to elastic deformation of each component based on the thrust load generated by the pressing device 12, etc. This displacement is absorbed without applying an excessive force to each component.

  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 (thrust bearing) 24 and a thrust rolling bearing are sequentially arranged from the outer surface side of the power roller 11. And thrust needle bearings 25 are provided. Among these, the thrust ball bearings 24 allow the rotation of each power roller 11 while supporting the load in the thrust direction applied to each power roller 11. Each of such thrust ball bearings 24 has a plurality of balls (hereinafter referred to as rolling elements) 26, 26 and an annular cage 27 for rollingly holding the rolling elements 26, 26, and a circle. It comprises an annular outer ring 28. Further, the inner ring raceway of each thrust ball bearing 24 is formed on the outer side surface (large end face) of each power roller 11, and the outer ring raceway is formed on the inner side surface of each outer ring 28.

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

  Further, drive rods (trunnion shafts) 29, 29 are provided at one end (lower end in FIG. 5) of each trunnion 15, 15, and a drive piston (an outer peripheral surface between the drive rods 29, 29 is provided) Hydraulic pistons 33, 33 are fixed. Each of the drive pistons 33, 33 is oil-tightly fitted in a drive cylinder 31 formed of an upper cylinder body 61 and a lower cylinder body 62. The drive pistons 33, 33 and the drive cylinder 31 constitute a drive device 32 for displacing the trunnions 15, 15 in the axial direction of the pivot shafts 14, 14 of the trunnions 15, 15.

  In the case of the toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 1 (shaft) is transmitted to the input side disks 2, 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 output to the output gear 4. It is taken out.

  When changing the rotational speed ratio between the input shaft 1 (shaft) and the output gear 4, the pair of drive pistons 33, 33 are displaced in opposite directions to each other. With the displacement of the drive pistons 33, the pair of trunnions 15, 15 are displaced in opposite directions. For example, the power roller 11 on the left side in FIG. 5 is displaced downward, and the power roller 11 on the right side in FIG. 5 is displaced upward.

  As a result, it acts on the contact portions between the circumferential surfaces 11a and 11a of the power rollers 11 and the inner side surfaces 2a, 2a, 3a and 3a of the input side disks 2 and 2 and the output side disks 3 and 3, respectively. The direction of the tangential force changes. Then, with the change in the direction of the force, the trunnions 15, 15 swing in opposite directions with respect to the pivots 14, 14 pivotally supported by the yokes 23A, 23B.

  As a result, the contact positions of the circumferential surfaces 11a, 11a of the power rollers 11, 11 and the inner side surfaces 2a, 3a change, and the rotational speed ratio between the input shaft 1 (shaft) and the output gear 4 changes. Do. In addition, when the torque transmitted between the input shaft 1 (shaft) and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11, 11 and the power rollers 11, 11 The attached outer rings 28, 28 rotate slightly around the proximal ends 23a, 23a of the displacement shafts 23, 23, respectively. Since the thrust needle bearings 25 and 25 exist between the outer surface of each of the outer rings 28 and 28 and the inner surface of the support plate portion 16 constituting each of the trunnions 15 and 15, respectively, the rotation smoothly proceeds. It will be. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 23, 23 may be small.

  Various proposals have conventionally been made for the power roller 11 used for the toroidal type continuously variable transmission, and for example, Japanese Patent Application Laid-Open No. 2001-108044 (the following patent document 1) describes the use of the toroidal type continuously variable transmission. The finishing surface of the power roller is subjected to final finishing only on the contact oval portion on the chain line representing the contact angle, and the range portion closer to the outer end surface than this portion, and the range portion not rolling contact with the mating surface There is described a method of reducing the manufacturing cost of the power roller while securing the yield strength of the power roller by not performing the final finishing process.

  As for the input disc 2 and the output disc 3 used for the toroidal type continuously variable transmission, for example, the traction drive mechanism has the direction of the rotation axis as disclosed in JP-A-11-082659 (Patent Document 2 below). An input disk and an output disk, which are disposed opposite to each other so as to be coincident, and the opposing contact surfaces are formed into a toroidal curved surface, and are rotatably supported around the center of curvature of the contact surfaces along a plane including the rotation axis. The transmission roller, the input disc, and the output, which are composed of the trunnion that has been used, the transmission roller that contacts each contact surface, and is rotatably supported by the trunnion, and the curvature of each contact surface changes continuously. Eliminates slippage in the contact area with the disc, improves the maximum allowable transmission force, and provides a long-life, high-reliability traction drive mechanism That method are described.

JP, 2001-108044, A Japanese Patent Application Laid-Open No. 11-082659

  In the above-mentioned toroidal type continuously variable transmission, although high efficiency is required, the main factor of loss is the traction surface where the power roller and the first and second disks make contact, and the power roller bearing Among them, most of the loss on the traction surface is the spin loss in the contact ellipse between the power roller and the first and second disks.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a highly efficient toroidal continuously variable transmission which reduces spin loss in the contact ellipse between the power roller and the first and second disks. With the goal.

In order to achieve the above object, a toroidal type continuously variable transmission according to the present invention comprises an axis, a first disc supported by the axis, and a second disc supported rotatably relative to the axis. the first disk and a power roller interposed between the second disk, the radius of curvature of the power roller in the traction surface and the power roller and the first and second disk comes into contact, it is changed in accordance with the form half apex angle of a normal line at the contact point with the axis of the power roller.

  In the present invention, the radius of curvature of the power roller on the traction surface where the power roller contacts the first and second disks changes in accordance with the half apex angle between the axis of the power roller and the contact point. Since it is possible to control the size of the contact ellipse between the power roller and the first and second disks, spin loss in the contact ellipse between the power roller and the first and second disks can be reduced. it can.

In this case, the radius of curvature of the sites half apex angle is small, the not smaller than the radius of curvature of the sites half apex angle is large. The radius of curvature of the traction surface of the power roller is set on the basis of the surface pressure generated at high load with a large half apex angle, so at low load with a small half apex angle, the power roller and the first and second disks The contact ellipse with this becomes larger and the spin loss becomes larger. Therefore, by making the radius of curvature of the portion with a small half apex angle smaller than the radius of curvature of the portion with a large half apex angle, in other words, the radius of curvature of the power roller on the traction surface By reducing the contact ellipse between the power roller and the first and second disks by reducing the movement according to the movement to the contact point of the disc, within the contact ellipse between the power roller and the first and second disks Spin loss can be reduced.

The curvature radius of the traction surface of the power roller, the that have continuously smaller in accordance with decrease of the half apex angle. By continuously reducing the radius of curvature of the traction surface of the power roller according to the decrease of the half apex angle, the spin loss in the contact ellipse between the power roller and the first and second disks is continuously made. It can be reduced.

  According to the present invention, it is possible to reduce the spin loss in the contact ellipse between the power roller and the first and second disks, and to provide a highly efficient toroidal continuously variable transmission.

BRIEF DESCRIPTION OF THE DRAWINGS It is principal part sectional drawing which shows the toroidal type continuously variable transmission of embodiment of this invention. It is the elements on larger scale which show the half apex angle which makes from the axis line of a power roller to a contact point. It is a figure which illustrates the embodiment of the power roller used for this invention. It is sectional drawing which shows an example of the concrete structure of the half toroidal type continuously variable transmission known conventionally. It is sectional drawing in alignment with the AA of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the toroidal-type continuously variable transmission of the present embodiment lies in the radius of curvature at the contact point of the power roller, and the other configuration and operation are the same as the conventional configuration and operation described above. Only the features of this embodiment will be mentioned, and the other parts will be described briefly with the same reference numerals as in FIGS. 4 and 5.

In the toroidal type continuously variable transmission of this embodiment shown in FIG. 1, the output side disc 3 is an integral type disc, and an outer peripheral portion thereof is an output gear 4.
The output gear 4 receives a gear reaction force from a gear (not shown) meshing with the output gear 4. In addition, this integrated output side disk 3 is rotatably supported on the input shaft (variator shaft (shaft)) 1 via a radial needle bearing, and the input shaft 1 (shaft) has a gear reaction force. Based bending load is to be applied.

  As shown in FIG. 1, in this toroidal type continuously variable transmission, a power roller 11 is held between the front input side disc 2 and the integral output side disc 3. Further, a power roller 11 is sandwiched between the integrated output side disc 3 and the rear side input side disc 2. A pressing force is applied from the pressing device 12 to the input side disk 2, the power roller 11 and the output side disk 3, and a cotter which positions the input side disk 2 on the rear side with a thrust load based on the pressing force. It has a structure that 36 receives.

  FIG. 2 is a partially enlarged view of the power roller 11 of FIG. As shown in FIG. 2, the half apex angle is an angle between the axis of the power roller 11 and the normal at the contact point, and in the case of FIG. 2, the radius of curvature RB at the contact point of the power roller 11 and the axial direction And the contact point becomes smaller as it moves from high load A to low load C.

  FIG. 3 is a view illustrating an embodiment of the power roller 11 used in the present invention, and FIG. 3 (a) shows a conventional power roller 11, and the dotted line in FIG. 3 (b) shows the conventional power roller and solid line. 1 shows a power roller 11 of the present invention. In the toroidal type continuously variable transmission of the present invention, as shown in FIG. 3A, when a load is applied. Mainly, the trunnion 15 and the yokes 23A and 23B are deformed, the position of the power roller 11 moves to the outside (the trunnion 15 side), and the contact point between the power roller 11 and the first and second disks 2 and 3 is At high load, the half apex angle gradually increases as the load is increased.

  Since the radius of curvature of the traction surface of the power roller 11 is set on the basis of the surface pressure generated at the time of high load with a large half apex angle, at low load with a small half apex angle, the power roller 11 and the first and second The contact ellipse with the disks 2 and 3 becomes large, and the spin loss becomes large. Therefore, as shown in FIG. 3 (b), the radius of curvature of the portion where the half apex angle is smaller is made smaller than the radius of curvature of the portion where the half apex angle is large, the power roller and the first and second disks By reducing the contact ellipse, spin loss in the contact ellipse between the power roller and the first and second disks 2 and 3 can be reduced. As a result, it is possible to increase the efficiency at the time of low load, which is effective for improving the fuel consumption, while keeping the load capacity, so it is possible to realize the high efficiency of the continuously variable transmission.

  Further, by continuously decreasing the radius of curvature of the traction surface of the power roller 11 according to the reduction of the half apex angle, within the contact ellipse of the power roller 11 and the first and second disks 2 and 3 Spin loss can be reduced continuously. By the above, the contact ellipse in the low load region where the half apex angle is small becomes small, and the spin loss is reduced. For this reason, since the radius of curvature of the traction surface on the high load side is large, the surface pressure can be made equal to or less than the allowable value, and efficiency improvement with low torque can be realized while keeping the load capacity.

  If the variator shaft (shaft) is structured to support the input side disk 2 and the output side disk 3, it is not the input shaft 1 (shaft) but the position of the input shaft 1 (shaft) described above. It may be an output shaft disposed instead of (axis). In the above embodiment, the pair of input side disks 2 is disposed outside, and the pair of output side disks 3 is disposed between the input side disks 2. However, the pair of output side disks 3 is disposed outside. The input side disk 2 may be provided integrally between the output side disks 3 and a gear for inputting a rotational torque may be integrally provided on the input side disk 2.

  The present invention can be applied to various half toroidal continuously variable transmissions such as a single cavity type and a double cavity type, and a full toroidal continuously variable transmission.

1 Input axis (axis)
2 Input disc (first disc)
3 Output side disk (second disk)
4 Output gear 11 Power roller 12 Pressing device

Claims (1)

A shaft, a first disk supported by the shaft, a second disk relatively rotatably supported by the shaft, and a power sandwiched between the first disk and the second disk In a toroidal type continuously variable transmission provided with a roller,
The radius of curvature of the power roller on the traction surface where the power roller contacts the first and second disks is continuous according to the reduction of the semi-apical angle between the axis of the power roller and the normal at the contact point. The toroidal type continuously variable transmission characterized in that

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