JP2007010046A - Toroidal type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toroidal type continuously variable transmission capable of reducing stress generated by an input shaft and increasing the allowable transmission torque of a variator. <P>SOLUTION: The toroidal type continuously variable transmission comprises a casing 200 incorporating a variator part which consists of the input shaft 18 to which rotating torque is input, an input side disc 2 and an output side disc 4 supported on the input shaft 18 mutually concentrically and rotatably with their inside faces opposing each other, and a power roller provided between the input side disc 2 and the output side disc 4 for transmitting the rotating force of the input side disc 2 to the output side disc 4 at a predetermined speed ratio. The input shaft 18 has the end located on the side of the output side disc 4 and non-rotatably supported on the casing 200 so as to receive only axial tensile force f1 operating on the input side disc 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In some cases, a toroidal continuously variable transmission as schematically shown in FIGS. 3 and 4 is used as an automobile transmission. This toroidal continuously variable transmission supports an input side disk 2 concentrically with an input shaft 1, and an output side disk 4 is fixed to an end of an output shaft 3 disposed concentrically with the input shaft 1. On the inner side of the casing containing the toroidal type continuously variable transmission, trunnions 6 and 6 are provided that swing around pivots (tilting shafts) 5 and 5 that are twisted with respect to the input shaft 1 and the output shaft 3. It has been.

  Further, by swinging each trunnion 6, 6 about each pivot 5, 5, the inclination angle of the displacement shaft 9 supported at the center of each trunnion 6, 6 can be adjusted. A power roller 11 is rotatably supported around the tip of the displacement shaft 9 protruding from the inner surface of each trunnion 6, 6, and each power roller 11, 11 is provided on the input side and the output side. It is sandwiched between both disks 2 and 4. In addition, the base end part and the front-end | tip part of each displacement shaft 9 and 9 are mutually eccentric.

  The cross sections of the inner side surfaces 2a and 4a facing each other of the input and output side disks 2 and 4 each form a concave surface obtained by rotating an arc centering on the pivot 5 or a curve close to such an arc. ing. And the peripheral surface 11a, 11a of each power roller 11, 11 formed in the spherical convex surface is contact | abutted to each inner surface 2a, 4a.

  Between the input shaft 1 and the input side disk 2, a loading cam type pressing device 12 is provided. The pressing device 12 elastically presses the input side disk 2 toward the output side disk 4. The pressing device 12 includes a cam plate (loading cam) 13 that rotates together with the input shaft 1 and a plurality of (for example, four) rollers 15 and 15 held by a cage 14. Further, a cam surface 16 that is an uneven surface is formed in the circumferential direction on one side surface (the left side surface in FIGS. 3 and 4) of the cam plate 13, and the outer surface of the input side disk 2 (see FIGS. 3 and 4). A similar cam surface 17 is also formed on the right side surface of FIG. The plurality of rollers 15 and 15 are supported so as to be rotatable about an axis extending in the radial direction with respect to the input shaft 1.

  In the toroidal type continuously variable transmission having such a configuration, when the input shaft 1 is rotated, the cam plate 13 is rotated along with the rotation of the input shaft 1, and the plurality of rollers 15, 15 are connected to the input side disk by the cam surface 16. 2 is pressed by the cam surface 17 provided on the outer side surface of the head. As a result, the input-side disk 2 is pressed against the plurality of power rollers 11, 11, and at the same time, based on the pressing between the pair of cam surfaces 16, 17 and the rolling surfaces of the plurality of rollers 15, 15. The input side disk 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the power rollers 11 and 11, and the output shaft 3 fixed to the output side disk 4 rotates.

  When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is performed between the input shaft 1 and the output shaft 3, the trunnions 6 and 6 are swung around the pivot shafts 5 and 5. As shown in FIG. 3, the peripheral surfaces 11 a and 11 a of the power rollers 11 and 11 are arranged near the center of the inner surface 2 a of the input disk 2 and the outer periphery of the inner surface 4 a of the output disk 4. The displacement shafts 9 and 9 are inclined so as to abut each other.

  On the other hand, when the speed is increased, the trunnions 6 and 6 are swung so that the peripheral surfaces 11a and 11a of the power rollers 11 and 11 have an inner surface 2a of the input side disk 2 as shown in FIG. Each of the displacement shafts 9 and 9 is inclined so as to come into contact with the outer peripheral portion and the central portion of the inner side surface 4 a of the output side disk 4. If the inclination angle of each of the displacement shafts 9 and 9 is intermediate between those shown in FIGS. 3 and 4, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.

  5 and 6 show a more specific single cavity type toroidal continuously variable transmission (see, for example, Patent Document 1). In the casing 200, the input side disk 2 and the output side disk 4 are supported around the input shaft 18 via needle bearings 19 and 19 so as to be rotatable and axially displaceable. The cam plate 13 for constituting the loading cam type pressing device 12 is spline-engaged with the outer peripheral surface of the end portion (left end portion in FIG. 5) of the input shaft 18. Further, an output gear 21 is connected to the output side disk 4 by a key 22 so that the output side disk 4 and the output gear 21 rotate in synchronization.

  The trunnions 6 and 6 that swing about the pivots (tilting shafts) 5 and 5 that are twisted with respect to the input shaft 18 are provided at both ends of the support plate 7 in the longitudinal direction (left-right direction in FIG. 6). The support plate portion 7 has a pair of bent wall portions 8 and 8 formed in a state of being bent toward the inner surface side. The bent wall portions 8 and 8 form a recessed pocket portion P in the trunnion 6 for accommodating a power roller 11 described later. Further, the pivots 5 and 5 are concentrically provided on the outer side surfaces (surfaces opposite to the support plate portion 7) of the bent wall portions 8 and 8, respectively.

  Both ends of the trunnions 6 and 6 are supported so as to be swingable and displaceable in the axial direction (left and right direction in FIG. 6) with respect to the pair of links (yokes) 23 and 23, respectively. The links 23 and 23 are supported by support posts 99A and 99B. And in the circular hole 10 formed in the center part of the support plate part (core part) 7 which comprises each trunnion 6 and 6, the displacement axis | shaft 9 with which the base end part 9a and the front-end | tip part 9b were mutually parallel and eccentric. The base end portion 9a is rotatably supported. A power roller 11 is rotatably supported around the distal end portion 9b of each displacement shaft 9 protruding from the inner side surface of each support plate portion 7.

  The pair of displacement shafts 9 and 9 provided for each pair of trunnions 6 and 6 are provided at positions 180 degrees opposite to the input shaft 18. Further, the direction in which the distal end portion 9b of each of the displacement shafts 9 and 9 is eccentric with respect to the base end portion 9a is the same as the rotational direction of both the input side and output side discs 2 and 4 (FIG. 6). In the opposite direction). The eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 18 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 18. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 18 due to elastic deformation of each component 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.

  In addition, a thrust rolling bearing is provided between the outer surface of each power roller 11, 11 and the inner surface of the support plate portion 7 constituting each trunnion 6, 6 in order from the outer surface side of the power roller 11. A ball bearing 24 and a thrust needle bearing 25 are provided. 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.

  Further, a drive rod 29 is coupled to one end portion (left end portion in FIG. 6) of each trunnion 6, 6, and a drive piston 30 is fixed to an outer peripheral surface of an intermediate portion of each drive rod 29. Each of these drive pistons 30 is fitted in the drive cylinder 31 in an oil-tight manner.

  In the case of the toroidal continuously variable transmission configured as described above, the rotation of the input shaft 18 is transmitted to the input-side disk 2 via the pressing device 12. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the pair of power rollers 11, 11, and the rotation of the output side disk 4 is further taken out from the output gear 21.

  When the rotational speed ratio between the input shaft 18 and the output gear 21 is changed, the pair of drive pistons 30 and 30 are displaced in directions opposite to each other. As the drive pistons 30 and 30 are displaced, the pair of trunnions 6 and 6 are displaced in directions opposite to each other. For example, the power roller 11 on the left side in FIG. 6 is displaced to the right side in the figure, and the power roller 11 on the right side in the figure is displaced to the left side in the figure. As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 4a of the input side disk 2 and the output side disk 4 changes. As the force changes, the trunnions 6 and 6 swing in directions opposite to each other about the pivots 5 and 5 pivotally supported by the links 23 and 23.

  As a result, as shown in FIG. 3 and FIG. 4 described above, the contact positions between the peripheral surfaces 11a and 11a of the power rollers 11 and 11 and the inner surfaces 2a and 4a change, and the input shaft 18 and the output gear are changed. The rotational speed ratio between 21 and 21 changes. When the torque transmitted between the input shaft 18 and the output gear 21 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11 and 11 and the outer ring 28 attached to each power roller 11 Rotate slightly around the base end 9a of each displacement shaft 9. Since each thrust needle bearing 25 exists between the outer side surface of each outer ring 28 and the inner side surface of the support plate portion 7 constituting each trunnion 6, the rotation can be performed smoothly. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 9, 9 can be small.

By the way, in the single cavity type toroidal continuously variable transmission (for example, Patent Document 1) having the above-described configuration, the input shaft 18 rotates with respect to the casing 200 to generate an axial direction generated by the loading cam type pressing device 12. The axial force f1 (hereinafter referred to as the input-side disk axial force or loading reaction force) acting on the input-side disk 2 and the torque are transmitted. The loading reaction force f <b> 1 is supported by the angular bearing 70 via the input shaft 18.
Further, for example, as disclosed in Patent Document 2, a torque transmission shaft that transmits torque and a tensile force transmission shaft that transmits tensile force are arranged on the same axis, and the tensile force transmission shaft has a link post at its center. A structure is also known in which the axial force generated by the pressing device 12 is not transmitted to the casing 200 at all by supporting the casing 200 via the casing 200.

Japanese Patent No. 3503348 JP 2001-108043 A

  However, in the structure disclosed in Patent Document 1, the input shaft 18 transmits both the torque and the input-side disk axial force f1, and the stress generated in the input shaft 18 is increased. Increase in the allowable transmission torque of the variator composed of the power roller 11 or the like is limited. Of course, it is possible to reduce the stress generated in the input shaft 18 by increasing the outer diameter R of the input shaft 18, but in such a case, the thickness T of the inner peripheral surface portion of the disks 2, 4 is thin. turn into. 7 (when the number of power rollers per cavity formed between the inner surface 2a of the input side disk 2 and the inner side surface 4a of the output side disk 4 is two) and FIG. 8 (per cavity) As shown in (when the number of power rollers is three), the disks 2 and 4 are deformed into an elliptical shape by the axial force generated by the pressing device 12, and the inner peripheral surface portions A and B (see FIG. 8, high stress (tensile force) is generated in A, B, C) (S 1, S 2 in FIG. 7 and S 1, S 2, S 3 in FIG. Therefore, when the wall thickness T at the inner peripheral surface portion of the disks 2 and 4 decreases, the strength of the disks 2 and 4 decreases, and as a result, an increase in the allowable transmission torque cannot be expected. . Further, when the number of power rollers 11 per cavity is increased to increase the density of torque transmission (for example, when the number of power rollers 11 is increased from two in FIG. 7 to three in FIG. 8), one contact point Since the hit pressing force is the same, the axial force increases, and this problem becomes remarkable.

  On the other hand, in the structure disclosed in Patent Document 2, the input shaft 18 always rotates in the opposite direction to one of the disks 2 and 4 (for example, the input side disk 2 rotates in the same direction as the input shaft 18). Therefore, the rotation speed of the rolling element of the bearing 19 provided on the inner peripheral surface portion of the disk rotating in the direction opposite to the input shaft 18 is extremely high. To be high. In addition to this, as described above, the inner peripheral surface portions of the disks 2 and 4 are deformed into an elliptical shape by the axial force generated by the pressing device 12, so that the durability of the bearing 19 is inevitably deteriorated. .

  Further, in the structure disclosed in Patent Document 2, the axial force generated by the pressing device 12 is supported by the casing 200 by supporting the tensile force transmission shaft at the center thereof with respect to the casing 200 via the link post. Therefore, the tensile force transmission shaft not only receives the input side disk axial force (loading reaction force) f1 on the input side disk 2 side than the link post, but also from the link post. On the output side disk 4 side, the output side disk axial force (axial force acting on the output side disk 4 with the input side disk axial direction force f1) f2 is received. The axial forces f1 and f2 acting on the disks 2 and 4 are equal to each other in the constant speed state, but on the deceleration side, the output-side disk axial force f2 is larger than the input-side disk axial force f1, and the speed increases. On the side, the input-side disk axial force f1 is larger than the output-side disk axial force f2, and the output-side disk axial force f2 at the time of maximum deceleration becomes maximum.

  In any case, in the configuration disclosed in Patent Document 2, since the output side disk axial force f2 acts, it is necessary to design in consideration of a large tensile force. Increase in transmission torque is limited.

  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 reduce the stress generated in the input shaft and increase the allowable transmission torque of the variator. And

  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-side disk and an output-side disk that are freely supported by the input shaft, and provided between the input-side disk and the output-side disk, and the rotational force of the input-side disk at a predetermined speed ratio on the output side In the toroidal-type continuously variable transmission in which a variator unit composed of a plurality of power rollers that transmit to a disk is incorporated in a casing, the input shaft receives only an axial tensile force acting on the input side disk. The end located on the output side disk is supported so as not to rotate with respect to the casing.

  In the toroidal type continuously variable transmission of the present invention, the input shaft does not rotate with respect to the casing, and therefore the input shaft does not transmit torque. Therefore, only the tensile force (input-side disk axial force) acts on the input shaft (the output-side disk axial force that causes a large tensile force does not act), resulting in lowering the stress generated on the input shaft. (The input shaft need only be able to withstand the input side disk axial force.) If the stress generated in the input shaft can be reduced in this way, it is not necessary to increase the diameter of the input shaft and reduce the thickness of the inner peripheral surface portion of the disk, and increase the allowable transmission torque of the variator section. Will be able to. In addition, since the input shaft does not rotate, the number of rotations of the rolling elements in the bearing provided on the inner peripheral portion of the disk also decreases, so that the durability of the bearing can be sufficiently ensured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The feature of the present invention lies in the mounting structure of the input shaft 18, and other configurations and operations are the same as those of the conventional configuration and operation described above. Therefore, in the following, only the features of the present invention will be referred to. Other parts are denoted by the same reference numerals as those in FIGS. 3 to 8 and detailed description thereof is omitted.

  FIG. 1 shows an embodiment of the present invention. As shown in the figure, in this embodiment, the input shaft 18 receives an axial tensile force f1 acting on the input-side disc 2 so that its end located on the output-side disc 4 side is on the casing 200. On the other hand, it is supported so that it cannot rotate. Specifically, the end of the input shaft 18 on the side where the output gear 21 is disposed is supported with respect to the casing 200 by a nut 93. In this case, a disc spring 90 and an insertion member 92 are disposed between the nut 93 and the casing 200. In the figure, reference numeral 72 denotes a drive shaft for inputting power.

  In such a configuration, the power (torque) input by the drive shaft 72 is transmitted to the input disk 2 via the cam plate 13 and the roller 15 of the pressing device 12 and then output via the power roller 11. This is transmitted to the side disk 4 and the output gear 21. That is, torque is not transmitted to the input shaft 18. Further, the input shaft 18 receives only the input-side disk axial force f1, and the output-side disk axial force f2 is supported by the casing 200 via the output gear 21 and the angular bearing 70.

  As described above, in the present embodiment, the input shaft 18 does not rotate with respect to the casing 200, and therefore the input shaft 18 does not transmit torque. Therefore, only the tensile force (input-side disk axial force f1) acts on the input shaft 18 (the output-side disk axial force f2 causing a large tensile force does not act), and as a result, the input shaft 18 generates (The input shaft 18 only needs to withstand only the input side disk axial force f1). In addition, if the stress generated in the input shaft 18 can be reduced in this way, it is not necessary to increase the diameter of the input shaft 18 and reduce the thickness T of the inner peripheral surface portion of the disks 2 and 4. The allowable transmission torque can be increased. Further, since the input shaft 18 does not rotate, the number of rotations of the rolling elements in the bearings 19 provided on the inner peripheral portions of the disks 2 and 4 also decreases, so that the durability of the bearings 19 can be sufficiently ensured.

FIG. 2 shows another embodiment of the present invention. As illustrated, in this embodiment, the input shaft 18 is completely fixed to the casing 200 by a nut 93. In the figure, reference numeral 72A denotes an input gear.
Even with such a configuration, it is possible to obtain the same effects as those of the above-described embodiment.

  The present invention can be applied to a toroidal type continuously variable transmission of various configurations of a single cavity type.

It is principal part sectional drawing of the toroidal type continuously variable transmission which concerns on embodiment of this invention. It is principal part sectional drawing of the toroidal type continuously variable transmission which concerns on other embodiment of this invention. It is a side view which shows the fundamental structure of the toroidal type continuously variable transmission conventionally known in the state at the time of maximum deceleration. It is a side view which shows the basic structure of the toroidal type continuously variable transmission conventionally known in the state at the time of maximum acceleration. It is sectional drawing which shows an example of the conventional concrete structure. It is sectional drawing which follows the XX line of FIG. It is the schematic which shows the deformation | transformation state (when the number of power rollers per cavity is two) of the disk by loading force. It is the schematic which shows the deformation | transformation state (when the number of power rollers per cavity is 3) of the disk by loading force.

Explanation of symbols

2 Input side disk 4 Output side disk 11 Power roller 18 Input shaft 200 Casing

Claims (1)

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 variator unit, which is provided between the output side disk and includes a plurality of power rollers that transmit the rotational force of the input side disk to the output side disk at a predetermined speed ratio. In a step transmission,
The input shaft is supported such that its end located on the output side disk is non-rotatable with respect to the casing so as to receive only an axial tensile force acting on the input side disk. A toroidal-type continuously variable transmission.

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