JP6729074B2 - Toroidal type continuously variable transmission - Google Patents

Description

The present invention relates to a toroidal type continuously variable transmission.

For example, as a double cavity type toroidal type continuously variable transmission used as a transmission for an automobile, ones shown in FIGS. 8 and 9 are known.
This double-cavity toroidal type continuously variable transmission is configured as shown in FIGS. 8 and 9. As shown in FIG. 8, an input shaft 1 is rotatably supported inside a casing 50, and two input side disks 2 and 2 and two output side disks 3 are provided on the outer periphery of the input shaft 1. 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. The output side disks 3 and 3 are connected to the 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 (loading cam) 7 located on the left side in the drawing. It has become. Further, the output gear 4 is supported in the casing 50 via the intermediate wall 13 formed by coupling of two members, whereby the output gear 4 can rotate about the axis O of the input shaft 1 while the axis O. Directional displacement is blocked.

As shown in FIG. 8, the output disks 3 and 3 are rotatably supported about the axis O of the input shaft 1 by needle bearings 5 and 5 interposed between the output disks 3 and 3. The input side disc 2 on the left side of the drawing is supported by the input shaft 1 via a ball spline 6, and the input side disc 2 on the right side of the drawing is spline-coupled to the input shaft 1. Are designed to rotate with the input shaft 1. In addition, power is provided between the inner side surfaces (concave surface; also called traction surface) 2a, 2a of the input side disks 2, 2 and the inner side surfaces (concave surface; also called traction surface) 3a, 3a of the output side disks 3, 3. The roller 11 (see FIG. 9) is rotatably held.

A step portion 2b is provided on the inner peripheral surface 2c of the input side disk 2 located on the right side in FIG. 8, and the step portion 1b provided on the outer peripheral surface 1a of the input shaft 1 is abutted against the step portion 2b. At the same time, the back surface (right surface in FIG. 8) of the input side disk 2 is abutted against a loading nut 9 screwed into a screw portion formed on the outer peripheral surface of the input shaft 1. As a result, the displacement of the input side disk 2 with respect to the input shaft 1 in the direction of the axis O 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. The disc spring 8 has concave surfaces 2a, 2a, 3a of the disks 2, 2, 3, 3. 3a and the peripheral surface 11a of the power roller 11, 11 and the contact portion of 11a are applied with a pressing force (preload).

FIG. 9 is a sectional view taken along the line AA of FIG. As shown in FIG. 9, inside the casing 50, a pair of trunnions 15 and 15 that swing about the pair of pivot shafts 14 and 14 that are twisted with respect to the input shaft 1 are provided. It should be noted that the illustration of the input shaft 1 is omitted in FIG. 9. Each trunnion 15, 15 has a pair of bent wall portions 20, 20 formed at both ends in the longitudinal direction (vertical direction in FIG. 9) of the support plate portion 16 so as to be bent toward the inner side surface of the support plate portion 16. have. The bent wall portions 20 and 20 form concave pocket portions P for accommodating the power roller 11 in the trunnions 15 and 15. Further, pivots 14, 14 are concentrically provided on the outer side surfaces of the bent wall portions 20, 20, respectively.

A circular hole 21 is formed in the center of the support plate portion 16, and the base end portion (first shaft portion) 23 a of the displacement shaft 23 is supported in the circular hole 21. By swinging the trunnions 15 and 15 around the pivots 14 and 14, the inclination angle of the displacement shaft 23 supported at the central portion of the trunnions 15 and 15 can be adjusted. Further, each power roller 11 is rotatably supported around the distal end portion (second shaft portion) 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15, and each power roller 11, Reference numeral 11 is sandwiched between the input side disks 2 and 2 and the output side disks 3 and 3. The base end portion 23a and the tip end portion 23b of each displacement shaft 23, 23 are eccentric to each other.

Further, the pivots 14, 14 of the trunnions 15, 15 are respectively supported by the pair of yokes 23A, 23B so as to be swingable and axially displaceable (vertical direction in FIG. 9). The trunnions 15, 15 are restricted from moving in the horizontal direction by 23B. Each of the yokes 23A and 23B is formed in a rectangular shape by pressing or forging metal such as steel. Four circular support holes 18 are provided at the four corners of each of the yokes 23A and 23B, and the pivots 14 provided at both ends of the trunnion 15 swing through the radial needle bearings 30 in the support holes 18, respectively. It is supported freely. Further, a circular locking hole 19 is provided at the center of the yokes 23A and 23B in the width direction (left-right direction in FIG. 8), and the inner peripheral surface of the locking hole 19 is a cylindrical surface. 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 23B is supported by the spherical post 68 and the drive that supports the spherical post 68. It is swingably supported by an upper cylinder body 61 of a cylinder (cylinder body) 31.

The displacement shafts 23, 23 provided on the trunnions 15, 15 are provided at positions 180 degrees opposite to each other with respect to the input shaft 1. Further, the direction in which the tip end portion 23b of each of these displacement shafts 23, 23 is eccentric with respect to the base end portion 23a is the same as the rotational direction of both discs 2, 2, 3, 3. (Reverse direction). Further, the eccentric direction is a direction substantially orthogonal to the arrangement direction of the input shaft 1. Therefore, the power rollers 11, 11 are supported so as to be slightly displaceable in the longitudinal direction of the input shaft 1. As a result, when the power rollers 11, 11 tend to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component based on the thrust load generated by the loading cam type pressing device 12 or the like. However, this displacement is absorbed without applying an unreasonable force to each component.

In addition, 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, which is a thrust rolling bearing, is provided in order from the outer surface side of the power roller 11. , And a thrust needle bearing 25. Of these, the thrust ball bearings 24 support the loads in the thrust direction applied to the power rollers 11 and allow the power rollers 11 to rotate. Such thrust ball bearings 24 are each provided with a plurality of balls (rolling elements) 26, 26, an annular retainer 27 rotatably holding each of these rolling elements 26, 26, and an annular outer ring. And 28. 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. The thrust needle bearing 25 as described above supports the thrust load applied from the power roller 11 to each outer ring 28, while the power roller 11 and the outer ring 28 swing about the base end portion 23 a of each displacement shaft 23. Tolerate.

Further, drive rods (trunnion shafts) 29, 29 are provided at one end portions (lower end portions in FIG. 9) of the trunnions 15, 15 respectively, and the drive pistons (trunnion shafts) are provided on the outer peripheral surfaces of the intermediate portions of the drive rods 29, 29. Hydraulic pistons 33, 33 are fixed. Each of the drive pistons 33, 33 is oil-tightly fitted in the drive cylinder 31 constituted by the upper cylinder body 61 and the 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 pivots 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 is transmitted to each of the input side disks 2 and 2 via the loading cam type pressing device 12. Then, the rotations of the input side disks 2 and 2 are transmitted to the output side disks 3 and 3 via the pair of power rollers 11 and 11, and the rotations of the output side disks 3 and 3 are further transmitted to the output gear 4. Taken out.

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. Along with the displacement of the drive pistons 33, 33, the pair of trunnions 15, 15 are displaced in opposite directions. For example, the power roller 11 on the left side of FIG. 9 is displaced to the lower side of the figure, and the power roller 11 on the right side of the figure is displaced to the upper side of the figure.

As a result, they act on the contact portions between the peripheral surfaces 11a and 11a of the power rollers 11 and 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 and 15 swing (tilt) in opposite directions about the pivots 14 and 14 pivotally supported by the yokes 23A and 23B.

As a result, the abutting positions of the peripheral surfaces 11a, 11a of the power rollers 11, 11 and the inner side surfaces 2a, 3a change, and the rotation speed ratio between the input shaft 1 and the output gear 4 changes. When the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the elastic deformation amount of each component changes, the power rollers 11, 11 and the outer ring attached to each of the power rollers 11, 11 change. 28 and 28 slightly rotate about the base end portions 23a and 23a of the displacement shafts 23 and 23, respectively. Thrust needle bearings 25, 25 exist between the outer surface of each outer ring 28, 28 and the inner surface of the support plate portion 16 constituting each trunnion 15, 15, so that the above-mentioned rotation can be performed smoothly. Be seen. Therefore, as described above, a small force is required to change the inclination angle of each displacement shaft 23.

In such a toroidal type continuously variable transmission, the power roller is pinched between the input and output side disks by a force corresponding to the transmission torque, so that the trunnion elastically deforms due to the pinching force (pressing force), It is unavoidable that the side disk is elastically deformed, and in many cases, in reality, the power roller cannot actually contact the input/output side disk at the designed position due to the elastic deformation.
In order to solve this, for example, a power roller support structure described in Patent Document 1 is known. In this power roller support structure, the power roller is brought close to the input/output side disk rotation axis so as to compensate for the deviation of the frictional engagement position between the power roller and the input/output side disk due to the deformation caused by the clamping pressure. The power roller is projected in the rotation axis direction, and the projection amount is configured to be larger when the tilting state is in the low side shift state than in the high side shift state.

Further, in the case of a toroidal type continuously variable transmission used as a transmission of an automobile, when the input shaft has a low torque such as when traveling downhill on a highway or when the engine is braked at high speed. The durability of the thrust ball bearing for bearing the thrust load applied to the power roller is impaired when it is rotated at high speed.
That is, when the thrust ball bearing is rotated at a high speed under a low load, the balls of the thrust ball bearing slip due to the gyro moment generated in the ball. Such slippage increases the rotational torque and heat generation amount of the thrust ball bearing due to an increase in frictional resistance, and deteriorates the durability of the thrust ball bearing.

Moreover, the contact surface pressure between the rolling contact part (traction part) between the peripheral surface of the power roller and the side surface of the disc and the rolling contact part inside the thrust ball bearing for rotatably supporting these power rollers is always appropriate. The structure described in Patent Document 2 is known as an example of a structure capable of preventing significant wear from occurring on each surface constituting these rolling contact portions by maintaining the rolling contact portion.
This structure includes a hydraulic thrust generator that generates thrust in a direction in which the input side disc and the output side disc are brought closer to each other, and a controller that controls the hydraulic pressure in order to adjust the thrust generated by this thrust generator. It has and. Then, this controller has a function of obtaining a first target value necessary for power transmission (traction transmission) between the input side disk and the output side disk, and each ball forming the thrust ball bearing of the power roller. Necessary to compare the first and second target values with the function to find the second target value necessary to prevent the state of revolving without rotating, and to generate thrust corresponding to a large target value. And a function of introducing a proper hydraulic pressure into the hydraulic thrust generator.

JP, 2004-68942, A JP, 2011-112103, A

By the way, attempts have been made to use the toroidal type continuously variable transmission in applications other than the transmission of an automobile, and one of them is considered to be applied to an aircraft generator. In the AC generator, in order to keep the frequency of the output AC current constant, the number of rotations of the generator (number of rotations per unit time: rotation speed) is made constant. Is an engine in which, when a generator is driven by the rotation of a turbine of an aircraft engine (for example, a turbo jet), a transmission is interposed between the rotation shaft of the turbine of the engine and the generator to change the rotation speed. The speed is changed so that the rotation speed of the output to the generator becomes constant with respect to the input from.
The toroidal transmission as a part of such an aircraft generator is required to be small and lightweight and to be operated at a high rotation speed.

In a toroidal continuously variable transmission for a generator, as shown in FIG. 10, the output rotation speed (the rotation speed N _OD of the output side disk) is constant and the input rotation speed (the rotation speed N _ID of the input side disk) fluctuates. If, for example, decelerated when the rotation speed N _ID of the input side disk is relatively high with respect to the rotational speed N _OD of the output side disc becomes constant, relatively low rotational speed N _ID of the input side disk In this case, since the speed is increased, the rotation speed N _ID of the input side disk and the rotation speed N _{PR of the} power roller are increased on the deceleration side as shown in FIG.
Note that the graphs of FIGS. 10 and 11 show the relative relationship of each item, and are not graphs based on actual numerical values, and therefore the scale and units are not shown on the horizontal axis and the vertical axis. Further, in the graph of FIG. 10 in which the reduction ratio (gear ratio) is shown on the horizontal axis as the deceleration side and the speed increasing side, for example, the deceleration side and the speed increasing side are not necessarily separated at the portion where the final gear ratio becomes 1. Not divided into sides. Here, in FIG. 10, when the fluctuating rotation speed N _ID of the input side disk is smaller than the rotation speed N _OD of the output side disk which is constant, the speed increasing side is set, and when it is larger, the speed reducing side is set.

As described above, the rotation speed N _ID of the input side disk and the rotation speed N _{PR of the} power roller increase on the deceleration side, that is, when the power roller rotates at a high speed with a low thrust load, it occurs in the ball of the thrust ball bearing. The gyro moment causes the balls of the thrust ball bearing to slip. Such slippage increases the rotational torque and heat generation amount of the thrust ball bearing due to an increase in frictional resistance, and deteriorates the durability of the thrust ball bearing. Therefore, there is a problem in suppressing the slippage of the thrust ball bearing due to the gyro moment.
FIG. 11 shows the relationship between the thrust force (Fpr: horizontal axis) of the thrust bearing of the power roller and the heat generation amount (vertical axis) of the thrust bearing during high rotation. As shown in FIG. 11, when the thrust force (load) applied to the thrust bearing (PR-BRG) of the power roller becomes smaller than a certain point (vertical dotted line in FIG. 11), rapid heat generation due to sliding occurs. Therefore, the thrust force of the thrust bearing of the power roller is designed to have a value (on the right of the position of the vertical dotted line in FIG. 11) at which sudden heat generation due to sliding does not occur.

On the other hand, if the pressing force is set to prevent sudden heat generation and damage due to PR-BRG sliding, it will be over-pressed under other reduction ratio conditions (particularly low torque conditions), and the variator (transmission) power transmission efficiency will increase. There is a concern that it will decrease and the durability life will decrease.
Therefore, by changing the thrust force to the PR-BRG depending on the operating conditions of the variator, particularly the rotational speed of the power roller, rapid heat generation due to slippage is suppressed in the deceleration side gear shift state where the rotational speed of the power roller becomes high. Is needed.

Further, in the structure described in Patent Document 2, since the thrust generating device (pressing device) is a hydraulic type, the control value of the pressing force can be arbitrarily determined depending on the operating conditions (torque, reduction ratio). Further, since it is a hydraulic type, the pressing force changes due to centrifugal oil pressure, and there is a concern that excessive pressing force may be generated in a toroidal type continuously variable transmission for aircraft generators that is operated at a high rotation speed.
On the other hand, in the loading cam type pressing device, the pressing force does not change due to the rotation, and the pressing force is determined only by the torque. Further, the loading cam type pressing device cannot change the pressing force depending on the reduction ratio. For this reason, there is a possibility that an excessive pressing force may be input, and there is a risk that the transmission efficiency and the yield strength may decrease.

The present invention has been made in view of the above circumstances, and in the case of shifting so that the output rotation speed is constant with respect to the fluctuating input rotation speed, the power is reduced in the deceleration side shift state in which the rotation speed of the power roller increases. An object of the present invention is to provide a toroidal type continuously variable transmission that can suppress rapid heat generation due to slippage in a thrust bearing of a roller.

In order to achieve the above-mentioned object, a toroidal type continuously variable transmission according to the present invention includes an input side disk and an output side disk that are concentrically and rotatably provided to each other in a state where their inner side surfaces face each other. A power cam held between the two disks and a loading cam type pressing device for pressing the two disks in a direction to bring them closer to each other, and the power roller is tilted about a tilt axis to change the speed. In the toroidal type continuously variable transmission for shifting so that the output rotation speed becomes constant with respect to the input rotation speed that fluctuates with
In a deceleration-side gear shift state in which the power roller tilts and the rotational speed of the power roller increases, a thrust force that suppresses slippage of the thrust bearing of the power roller is applied to the power roller. It is characterized by being provided with a thrust force imparting structure for imparting stronger than in the speed-up side shift state in which the number becomes low.

According to the present invention, in the deceleration side gear shift state in which the power roller is tilted and the rotational speed of the power roller is increased, the thrust force imparting structure prevents the power roller from slipping on the thrust bearing of the power roller. Since a strong thrust force is applied more strongly than in the speed-up side shift state, it is possible to suppress the sudden heat generation of the thrust bearing due to this slip. Further, it is possible to prevent the input of an excessive pressing force, and it is possible to improve the transmission efficiency and the yield strength.

Further, in the above configuration of the present invention, in the thrust force imparting structure, a half apex angle formed by a normal line at a contact point between the disks and the power roller and a rotation axis of the power roller is a rotation of the power roller. It may be configured by setting so that the deceleration side shift state in which the rotation number of the power roller is high becomes smaller than the acceleration side shift state in which the number becomes lower.

According to such a configuration, the half-vertical angle is set to be smaller in the deceleration-side gear shift state in which the power roller rotation speed is higher than in the speed-up gear shift state in which the power roller rotation speed is low. Therefore, in the deceleration side shift state, the power roller is pushed out toward the disc more strongly than in the speed up side shift state. For this reason, the thrust force applied to the power roller is greater in the deceleration side gear shift state than in the speed increase side gear shift state. Therefore, slippage of the thrust bearing of the power roller is suppressed and the thrust bearing abruptly changes. Heat generation can be suppressed.

Further, in the configuration of the present invention, in the thrust force applying structure, the cavity diameter of the input side disk is set to be larger than the reference cavity diameter, and the radius of curvature of the traction surface of the input side disk with which the power roller contacts is set. It is set smaller than the standard radius of curvature,
The cavity diameter of the output side disc is set smaller than the reference cavity diameter, and the radius of curvature of the traction surface of the output side disc with which the power roller contacts is set smaller than the reference radius of curvature. Good.

With this configuration, the cavity diameter of the input side disc is set to be larger than the reference cavity diameter, the radius of curvature of the traction surface of the input side disc is set to be smaller than the reference radius of curvature, and the cavity diameter of the output side disc is set to the reference Since it is set smaller than the cavity diameter and the radius of curvature of the traction surface of the output side disc is set smaller than the reference radius of curvature, the normal line at the contact point between both discs and the power roller and the rotation axis of the power roller form The half-vertical angle is smaller in the deceleration side shift state in which the power roller rotation speed is higher than in the acceleration side shift state in which the power roller rotation speed is low. Therefore, in the deceleration-side shift state, the power roller is pushed out toward the disc more strongly than in the acceleration-side shift state, so the thrust force applied to the power roller is greater in the deceleration-side shift state than in the acceleration-side shift state. growing. Therefore, it is possible to suppress slippage of the thrust bearing of the power roller, and to suppress rapid heat generation of the thrust bearing due to this slippage.

Further, in the above configuration of the present invention, in the thrust force applying structure, the position of the yoke hole that determines the position of the tilt axis of the power roller is the output side disk side in the axial direction of the input side disk from the reference position. May be configured by being offset to.

With this configuration, the position of the yoke hole that determines the position of the tilt axis of the power roller is offset from the reference position to the output side disc side in the axial direction of the input side disc, so that the deceleration side shift state In this case, since the power roller is pushed out toward the disc more strongly than in the speed-up side shift state, the thrust force applied to the power roller is larger in the deceleration-side shift state than in the speed-up side shift state. Therefore, it is possible to suppress slippage of the thrust bearing of the power roller, and to suppress rapid heat generation of the thrust bearing due to this slippage.

ADVANTAGE OF THE INVENTION According to this invention, in the deceleration side speed change state where the rotation speed of the power roller of the toroidal type continuously variable transmission which shifts so that an output rotation speed may become fixed becomes high, the power roller is made to contact the power roller by the thrust force imparting structure. Since the thrust force that suppresses the slip of the thrust bearing is applied more strongly than the speed-increasing gear shift state, it is possible to suppress the sudden heat generation of the thrust bearing due to the slip.

FIG. 3 is a half cross-sectional view of both disks for explaining a deceleration side speed change state, showing an essential part of the toroidal type continuously variable transmission according to the first embodiment of the present invention. FIG. 3 is a half cross-sectional view of both discs for explaining the speed-up side shift state. FIG. 3 is a sectional view of a disk for explaining the cavity diameter of the same. FIG. 6 is a half cross-sectional view of both disks for explaining a deceleration side speed change state, showing an essential part of a toroidal type continuously variable transmission according to a second embodiment of the present invention. FIG. 3 is a half cross-sectional view of both discs for explaining the speed-up side shift state. FIG. 6 is a half cross-sectional view for explaining a deceleration side gear shifting state, showing an essential part of a toroidal type continuously variable transmission according to a third embodiment of the present invention. FIG. 7 is a half cross-sectional view for explaining the speed-up side shift state. It is sectional drawing which shows an example of the conventional toroidal type continuously variable transmission. It is sectional drawing which follows the AA line in FIG. Relative relationship between the speed reduction ratio and the rotation speed of each of the input side disk (ID), the output side disk (OD) and the power roller (PR) and the speed reduction ratio assumed in the toroidal type continuously variable transmission used in the aircraft generator. It is a graph which shows. 6 is a graph showing a relative relationship between a thrust force of a thrust bearing of a power roller and a heat generation amount, which is assumed in a toroidal type continuously variable transmission of an aircraft generator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
1 and 2 show a main part of a toroidal type continuously variable transmission according to a first embodiment of the present invention, and are half-sectional views of an input side disk 2 and an output side disk 3. 1 and 2, the power roller sandwiched between the input/output side disks 2 and 3 is not shown. Further, in FIGS. 1 and 2, the traction surface 2A of the input side disk 2 and the traction surface 3A of the output side are shown as deformed respectively. Therefore, actually, the radius of curvature R _I of the traction surface 2A is slightly smaller than the radius of curvature R _S of the reference traction surface 2a, and the radius of curvature R _O of the traction surface 3A is the radius of curvature R _S of the reference traction surface 3a. It is slightly smaller.
Also, a tilting center of the sign O _P point indicated by the power rollers, through the tilting center O _P, and a line perpendicular to the axis O of both the disc 2 is tilt axis.

Further, the toroidal type continuously variable transmission according to the present embodiment and the second and third embodiments to be described later is a transmission used in an aircraft generator, and the number of revolutions from an aircraft engine. The variable speed is changed to a constant speed and output to the generator. Further, the toroidal type continuously variable transmission of the first to third embodiments includes a pair of input side disks 2 and 2 and a pair of output side disks 3 and 3 similar to the conventional toroidal type continuously variable transmission. The double-cavity half toroidal type continuously variable transmission has a configuration on the input side and a configuration on the output side substantially opposite to those of the conventional toroidal type continuously variable transmission. However, the basic configuration is the same as that of the above-described conventional toroidal type continuously variable transmission for automobiles, and the same configuration as that of the related art will not be illustrated and described.

In the toroidal type continuously variable transmission according to the present embodiment, in the deceleration-side gear shifting state (state shown in FIG. 1) in which the power roller tilts and the rotation speed of the power roller increases, the power roller is fed with the power. A thrust force applying structure 100 is provided that applies a thrust force that suppresses slippage of the thrust bearing of the roller more strongly than in the speed-up side speed change state where the rotation speed of the power roller decreases.

Here, as shown in FIG. 3, the (input/output side) disk 2 (3) of the toroidal type continuously variable transmission has a traction surface 2a (3a) having an arcuate cross section that contacts the power roller. Curvature radius _{R S} of the traction surface 2a (3a), when the center of curvature and _{O R,} the center of curvature _O R are two spaced apart in the radial direction of the disk 2 (3), the distance a cavity diameter of between _{O R} Define as D _S.

As shown in FIGS. 1 and 2, the thrust force applying structure 100 has a cavity diameter D _I of the input side disk 2 set to be larger than a reference cavity diameter D _S and traction of the input side disk 2 with which the power roller contacts. The radius of curvature R _I of the surface 2A is set smaller than the reference radius of curvature R _S , the cavity diameter D _O of the output side disc 3 is set smaller than the reference cavity diameter D _S , and the output side disc 3 with which the power roller contacts is set. The radius of curvature R _O of the traction surface 3A is set to be smaller than the reference radius of curvature R _S.
1 and 2, the radius of curvature of the traction surfaces 2a and 3a indicated by the two-dot chain lines of the input/output side disks 2 and 3 is the reference radius of curvature R _S. With reference to the conventional input/output side disk having the traction surfaces 2a and 3a having the reference radius of curvature R _S and the reference cavity diameter D _S, and having the outer diameter equal to that of the input/output side disks 2 and 3, the cavity diameter D is used. _{I, the} radius of curvature R _I , the cavity diameter D _O , and the radius of curvature R _O are set as described above.

In the present embodiment, the half-vertical angle θ formed by the normal line H at the contact point between the input side disk 2 and the output side disk 3 and the power roller and the rotation axis S of the power roller is the power roller shown in FIG. 1 is smaller in the deceleration side shift state in which the power roller rotation number is higher than in the acceleration side shift state in which the rotation number is low.
Therefore, in the deceleration side shift state, the power roller is pushed out toward the disc more strongly than in the speed up side shift state, so the thrust force applied to the power roller is larger in the deceleration side shift state than in the speed up side shift state. Become. Therefore, slippage of the thrust bearing of the power roller can be suppressed, and abrupt heat generation of the thrust bearing due to this slip can be suppressed. Further, as shown in FIG. Since the angle θ becomes large, it is possible to prevent an excessive load from being input to the thrust bearing of the power roller, and it is possible to secure durability and improve efficiency.

(Second embodiment)
Next, a second embodiment of the present invention will be described.
4 and 5 show a main part of a toroidal type continuously variable transmission according to a second embodiment of the present invention, and are half-sectional views of an input side disk 2 and an output side disk 3. 4 and 5, the power roller sandwiched between the input/output side disks 2 and 3 is not shown.
In the present embodiment, in the deceleration-side gear shift state (state shown in FIG. 4) in which the rotational speed of the power roller is high (a state shown in FIG. 4 ), the thrust that gives the power roller thrust force that suppresses slippage of the thrust bearing of the power roller. Since the structure of the force applying structure 101 is different from that of the first embodiment, this difference will be described below.

As shown in FIGS. 4 and 5, in the thrust force imparting structure 101, the position of the yoke hole that determines the position of the tilting shaft of the power roller is on the output side disc 3 side in the axial direction of the input side disc 2 from the reference position. It is constructed by being offset to.
That is, first, the point indicated by the reference sign O _P is the tilt center that serves as the reference of the power roller, and the tilt that serves as the reference is a line that passes through this tilt center O _{P and} that is orthogonal to the axis O of both disks 2 and 3. It is an axis. This tilt axis passes through the center position of the hole (support hole 18 shown in FIG. 9) of the yoke, and the pivot of the trunnion (the pivot 14 shown in FIG. 9) that supports the power roller in this hole is rotated around the tilt axis. It is fitted so that it can be tilted freely. Therefore, in FIG. 4 and FIG. 5 shows the center position of the hole in the yoke tilting center O _P is the reference.
In the present embodiment, the center position of the hole of the yoke is offset by a predetermined length on the output side disks 3 side in the axial direction of the input side disk 2 from the reference position O _P. The center position of the hole of the offset has been yoke and code O _S. In order to offset the position of the hole of the yoke, the support hole 18 formed in the yoke shown in FIG. 9 may be formed so as to be shifted on the output side disk 3 side by a predetermined length.

In this manner, in the present embodiment, the hole position of the yoke which determines the position of the tilt axis of the power roller, the reference position O _P position is offset to the output side disk 3 side in the axial direction of the input side disk 2 from O _S Therefore, in the deceleration side shift state shown in FIG. 4, the power roller is pushed out toward the disc more strongly than in the speed up side shift state shown in FIG. 5, and the half-vertical angle θ becomes smaller. Therefore, the thrust force applied to the power roller is greater in the deceleration side gear shifting state than in the speed increasing side gear shifting state, so that slippage of the thrust bearing of the power roller is suppressed, and sudden heat generation of the thrust bearing due to the slippage is suppressed. Can be suppressed.
Further, as shown in FIG. 5, the half-vertical angle θ becomes larger in the speed-up side shift state than in the deceleration-side shift state, so that it is possible to prevent the excessive load from being input to the thrust bearing of the power roller, and the durability is improved. It is possible to secure and improve efficiency.

(Third Embodiment)
Next, a third embodiment of the present invention will be described.
6 and 7 show a main part of a toroidal type continuously variable transmission according to a third embodiment of the present invention, which is a half sectional view of an input side disk 2 and an output side disk 3 including a power roller 11. is there.
In the present embodiment, in the deceleration-side gear shift state (state shown in FIG. 6) in which the rotation speed of the power roller 11 becomes high, the power roller 11 has a thrust force that suppresses slippage of the thrust bearing 24 of the power roller 11. Since the structure of the thrust force imparting structure 102 for imparting a difference is different from that of the first and second embodiments, this difference will be described below.

As shown in FIGS. 6 and 7, in the thrust force applying structure 102, a half vertical angle θ between the normal line H at the contact point between the disks 2 and 3 and the power roller 11 and the rotation axis S of the power roller 11 is formed. Since the speed-up side shift state in which the rotation speed of the power roller 11 shown in FIG. 7 is low is set to be smaller than the deceleration-side shift state in which the rotation speed of the power roller 11 is high shown in FIG. ,It is configured.

In order to configure the thrust force imparting structure 102 in this way, for example, similarly to the second embodiment described above, the position of the yoke hole that determines the position of the tilt axis of the power roller 11 is input from the reference position. It may be offset toward the output side disk 3 side in the axial direction of the side disk 2, or may be a value obtained by increasing or decreasing the radius of curvature of the traction surface of the power roller 11 from the reference radius of curvature by a predetermined value, or other configurations. May be adopted.
In short, the half-vertical angle θ formed by the normal line H at the contact point between the disks 2 and 3 and the power roller 11 and the rotation axis line S of the power roller 11 is set to the speed-increasing side shift at which the rotational speed of the power roller 11 decreases. Any configuration may be adopted as long as it can be set so as to be smaller in the deceleration side shift state in which the rotation number of the power roller 11 is higher than in the state.

In the present embodiment, the thrust force applied to the power roller 11 is greater in the deceleration side gear shift state than in the speed increase side gear shift state. Therefore, slippage of the thrust bearing 24 of the power roller 11 is suppressed and It is possible to suppress sudden heat generation of the thrust bearing 24.
Further, as shown in FIG. 7, the half-vertical angle θ is larger in the speed-up side shift state than in the deceleration-side shift state, so that it is possible to prevent an excessive load from being input to the thrust bearing 24 of the power roller 11, It is possible to secure durability and improve efficiency.

In each of the above-described embodiments, the case where the present invention is applied to the double cavity half toroidal type continuously variable transmission has been described as an example, but the present invention is not limited to this, and the present invention is not limited to the single cavity half It can be applied to toroidal type and full toroidal type toroidal type continuously variable transmissions.

2 Input side disk 3 Output side disk 11 Power roller 12 Pressing device 18 Support hole (Yoke hole)
23A, 23B Yoke 100, 101, 102 Thrust force applying means

Claims (2)

The input side disk and the output side disk, which are concentrically and rotatably provided with the inner surfaces thereof facing each other, the power roller sandwiched between the both disks, and the both disks A loading cam type pressing device that presses in a direction of approaching each other, so that the power roller is tilted about a tilt axis to perform gear shifting, and the output speed is constant with respect to a fluctuating input speed. In a toroidal type continuously variable transmission for shifting,
In a deceleration-side gear shift state in which the power roller tilts and the rotational speed of the power roller increases, a thrust force that suppresses slippage of the thrust bearing of the power roller is applied to the power roller. Equipped with a thrust force applying structure that applies more strongly than the speed increasing side shift state where the number becomes low ,
In the thrust force imparting structure, the cavity diameter of the input side disc is set to be larger than the reference cavity diameter, and the radius of curvature of the traction surface of the input side disc with which the power roller contacts is set to be smaller than the reference radius of curvature.
The cavity diameter of the output side disc is set smaller than the reference cavity diameter, and the radius of curvature of the traction surface of the output side disc with which the power roller contacts is set smaller than the reference radius of curvature. A toroidal type continuously variable transmission characterized in that The input side disk and the output side disk, which are concentrically and rotatably provided with the inner surfaces thereof facing each other, the power roller sandwiched between the both disks, and the both disks A loading cam type pressing device that presses in a direction of approaching each other, so that the power roller is tilted about a tilt axis to perform gear shifting, and the output speed is constant with respect to a fluctuating input speed. In a toroidal type continuously variable transmission for shifting,
In a deceleration-side gear shift state in which the power roller tilts and the rotational speed of the power roller increases, a thrust force that suppresses slippage of the thrust bearing of the power roller is applied to the power roller. Equipped with a thrust force applying structure that applies more strongly than the speed increasing side shift state where the number becomes low,
In the thrust force applying structure, the position of the yoke hole that determines the position of the tilt axis of the power roller is offset from the reference position to the output side disk side in the axial direction of the input side disk. A toroidal continuously variable transmission characterized by being used.

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