JP3293304B2 - Toroidal type continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The toroidal type continuously variable transmission according to the present invention is used, for example, as a transmission for an automobile or as a transmission for various industrial machines.

[0002]

2. Description of the Related Art As a transmission for a motor vehicle, to be used a substantially toroidal-type continuously variable transmission that such shown in FIGS. 2-3 have been studied. This toroidal-type continuously variable transmission supports an input disk 2 concentrically with an input shaft 1 and is disposed concentrically with the input shaft 1 as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 62-71465. An output disk 4 is fixed to an end of the output shaft 3. Inside the casing containing the toroidal-type continuously variable transmission, trunnions 6 and 6 that swing about pivots 5 and 5 that are twisted with respect to the input shaft 1 and the output shaft 3 are provided. .

Each of the trunnions 6, 6 has the pivots 5, 5 on the outer surfaces of both ends. The center of each trunnion 6, 6 supports the base end of the displacement shaft 7, 7 and swings each trunnion 6, 6 around the pivot 5, 5, thereby allowing each displacement shaft 7, 6 to swing. The inclination angle of 7 can be freely adjusted. Power rollers 8, 8 are rotatably supported around displacement shafts 7, 7 supported by the trunnions 6, 6, respectively. The power rollers 8 are sandwiched between the input side and output side disks 2, 4.

The inner surfaces 2a and 4a of the input and output disks 2 and 4 which are opposed to each other have cross sections each having a concave surface obtained by rotating an arc around the pivot 5. The peripheral surfaces 8a, 8a of the power rollers 8, 8 formed on the spherical convex surfaces are in contact with the inner side surfaces 2a, 4a.

[0005] A loading device 9 of a loading cam type is provided between the input shaft 1 and the input disk 2, and the input disk 2 is directed toward the output disk 4 by this pressing device 9 so as to be elastic. Pressing. This pressing device 9
Is a cam plate 10 that rotates together with the input shaft 1 and a retainer 11
(For example, four) rollers 12 held by
12. On one side surface (left side surface in FIGS. 2 and 3 ) of the cam plate 10, a cam surface 13 which is an uneven surface extending in a circumferential direction is formed, and an outer side surface of the input side disk 2 (right side in FIGS. Surface) also has a similar cam surface 14 formed thereon. The plurality of rollers 12 are supported rotatably about an axis in a radial direction with respect to the center of the input shaft 1.

When the cam plate 10 rotates with the rotation of the input shaft 1 during use of the toroidal type continuously variable transmission configured as described above, a plurality of rollers 12, 1
2 is pressed against the cam surface 14 on the outer surface of the input disk 2. As a result, the input side disk 2 is pressed by the plurality of power rollers 8 and 8 and at the same time, based on the engagement between the pair of cam surfaces 13 and 14 and the plurality of rollers 12, The input side disk 2 rotates. And
The rotation of the input disk 2 is transmitted to the output disk 4 via the plurality of power rollers 8, and the output shaft 3 fixed to the output disk 4 rotates.

When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6, 6 are pivoted about the pivots 5, 5.
And the peripheral surfaces 8a, 8a of the power rollers 8, 8
As shown in FIG. 2 , each of the displacement shafts 7 is inclined so as to abut on a portion of the inner surface 2 a of the input disk 2 near the center and a portion of the inner surface 4 a of the output disk 4 near the outer periphery.

Conversely, when increasing the speed, the trunnions 6, 6 are swung so that the peripheral surfaces 8a, 8a of the power rollers 8, 8, as shown in FIG. A portion near the outer periphery of the side surface 2a and an inner side surface 4a of the output side disk 4
The respective displacement shafts 7 are inclined so as to abut against the portion near the center of. FIG. 2 shows the inclination angles of the displacement shafts 7 and 7 .
3 and FIG. 3 , an intermediate speed ratio can be obtained between the input shaft 1 and the output shaft 3.

FIGS. 4 to 7 show Japanese Utility Model Application No. 63-6929.
3 shows a more specific toroidal-type continuously variable transmission described in Microfilm No. 3 (Japanese Utility Model Laid-Open No. 1-173552). Input disk 2 and output disk 4
Is rotatably supported around a cylindrical input shaft 15 via needle bearings 16 and 16, respectively. Further, the cam plate 10 is spline-engaged with the outer peripheral surface of the end portion (left end portion in FIG. 4 ) of the input shaft 15, and is prevented from moving away from the input side disk 2 by the flange portion 17. Then, based on the rotation of the input shaft 15, the input side disk 2 is rotated by the cam plate 10 and the rollers 12 and 12.
Is rotated while being pressed toward the output side disk 4,
The loading device 9 of the loading cam type is constituted. The output side disk 4 is provided with an output gear 18 and keys 19, 19.
Output disk 4 and output gear 18
And rotate in synchronization.

Both ends of the pair of trunnions 6, 6 are supported on a pair of support plates 20, 20 so as to be swingable and displaceable in the axial direction (front and back directions in FIG . 4 and left and right directions in FIG. 5 ) . I have.
The displacement shafts 7, 7 are supported by circular holes 23, 23 formed in the middle portions of the trunnions 6, 6, respectively. Each of the displacement shafts 7 is parallel and eccentric to the support shaft 2.
1 and 21 and pivot shaft portions 22 and 22, respectively.
Of these, the support shafts 21, 21 are inserted into the respective circular holes 23, 23.
Are rotatably supported through needle bearings 24, 24 inside. A power roller 8, 8 is provided around each of the pivot shafts 22, 22 with another needle bearing 25, 25.
It is rotatably supported via.

The pair of displacement shafts 7, 7 are provided at positions opposite to the input shaft 15 by 180 degrees. or,
The direction in which the respective pivot shaft portions 22, 22 of these displacement shafts 7, 7 are eccentric with respect to the support shaft portions 21, 21 depends on the input side,
The same direction as the rotation direction of both output side disks 2 and 4 ( Fig.
5 is the opposite direction). Further, the eccentric direction is a direction substantially perpendicular to the disposing direction of the input shaft 15. Therefore, each of the power rollers 8 is connected to the input shaft 1.
5 is supported so as to be slightly displaceable in the arrangement direction. As a result, even if the power rollers 8 tend to be displaced in the axial direction of the input shaft 15 due to the dimensional accuracy of the components, etc., without applying excessive force to the components, This displacement can be absorbed.

A thrust rolling bearing is provided between the outer surface of each of the power rollers 8, 8 and the inner surface of the intermediate portion of each of the trunnions 6, 6 in order from the outer surface of the power rollers 8, 8. Thrust ball bearings 26 and 26 and thrust needle bearings 27 and 27 are provided. The thrust ball bearings 26 support the load in the thrust direction applied to the power rollers 8 and allow the power rollers 8 to rotate. Such thrust ball bearings 26, 26 each have a plurality of ball 2
9, 29, annular retainers 28, 28 for rollingly holding the balls 29, 29, and annular outer rings 30, 30. The inner raceway of each thrust ball bearing 26, 26 is formed on the outer surface of each of the power rollers 8, 8, and the outer raceway is formed on the inner surface of each of the outer races 30, 30, respectively.

The thrust needle bearings 27, 27
Is composed of a race 31, a retainer 32, and needles 33, 33 as shown in FIGS . Race 3 of these
1 and the retainer 32 are combined so as to be slightly displaceable in the rotational direction. The race 31 and the cage 3
2 is an annular portion 34a centered on the support shaft portion 21 ,
34b, and projecting portions 35a, 35b projecting diametrically outward from a part of the outer periphery of each of the annular portions 34a, 34b.

Such thrust needle bearings 27, 27
In a state where the races 31, 31 are in contact with the inner surfaces of the trunnions 6, 6, the inner surfaces and the outer race 3
It is sandwiched between the outer surfaces of 0 and 30. In addition, the arrangement direction of each of the protrusions 35a and 35b is the same as that of the support shaft 21,
The eccentric directions of the pivot shaft portions 22, 22 with respect to 21. Such thrust needle bearings 27, 27
While supporting the thrust load applied to each of the outer rings 30, 30 from each of the power rollers 8, 8, the pivot shaft portion 22,
22 and the outer races 30, 30 are supported by the support shafts 21, 21.
Swing around the center.

Furthermore, the one end attached to each drive rod 36, 36 (left end in FIG. 5), the drive piston 37 to the intermediate outer peripheral surface of the drive rod 36, 36 of the trunnions 6, 37 are fixed. Then, these drive pistons 37 are respectively connected to the drive cylinders 3.
8 and 38 are fitted in an oil-tight manner.

In the case of the toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 15 is transmitted to the input disk 2 via the pressing device 9. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the pair of power rollers 8, 8, and the rotation of the output side disk 4 is taken out from the output gear 18.

When changing the rotation speed ratio between the input shaft 15 and the output gear 18, the pair of drive pistons 37,
37 are displaced in opposite directions. With the displacement of each of the drive pistons 37, 37, the pair of trunnions 6,
6, displaced in opposite directions, for example, on the right side of the lower power roller 8 is the drawing of FIG. 5, the left side of the power roller 8 of the upper side of the figure drawing, displaced respectively. As a result, the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner surfaces 2a, 4a of the input side disk 2 and the output side disk 4 are formed.
The direction of the tangential force acting on the abutting portion changes. Then, with the change in the direction of the force, the trunnions 6, 6 are pivotally supported by the support plates 20, 20, respectively.
5 oscillate in mutually opposite directions.

As a result, as shown in FIGS.
The contact position between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner surfaces 2a, 4a changes, and the input shaft 15
The rotation speed ratio between the output gear 18 and the output gear 18 changes.

In order to change the rotational speed ratio between the input shaft 15 and the output gear 18, the displacement shafts 7, 7
When changing the inclination angle of each of these displacement axes 7, 7
Slightly rotate about the support shaft portions 21, 21. As a result of this rotation, each of the thrust ball bearings 26, 26
The outer surfaces of the outer races 30, 30 and the inner surfaces of the trunnions 6, 6 are relatively displaced. Since the thrust needle bearings 27 exist between the outer surface and the inner surface, the force required for the relative displacement is small. Therefore, the force for changing the inclination angle of each of the displacement shafts 7 can be small as described above.

[0020] Although not described in publications such as, FIG
The present inventors previously considered a thrust needle bearing as shown in FIG. 8 as a thrust needle bearing according to the structure of No. 6 . This thrust needle bearing has an annular main cage 3
9 and arc-shaped auxiliary holders 40a, 40b, and each of the holders 39, 40a, 40b holds a plurality of needles 33, 33 in each of the pockets 41, 41 so as to roll freely. Consisting of The main retainer 39 is disposed around the support shaft 21 that constitutes the displacement shaft 7, and the sub retainers 40 a and 40 b are connected to the pivot shaft 22 with respect to the support shaft 21.
In the outer part of the main retainer 39 in accordance with the eccentric direction of. In any case, in the case of the conventional thrust needle bearing, the plurality of needles 33, 33 having the same outer diameter and the same length are used.

[0021]

However, in the case of a toroidal type continuously variable transmission constructed and operated as described above, there are the following points to be solved. That is, the thrust needle bearing 2 provided between the outer surfaces of the outer rings 30, 30 of the thrust ball bearings 26, 26 and the inner surfaces of the trunnions 6, 6.
The thrust load applied to 7 becomes non-uniform in the plane direction. Such non-uniformity of the thrust load is caused by elastic deformation of the trunnions 6, 6 based on the thrust load applied to the power rollers 8, 8.

That is, when the toroidal type continuously variable transmission is operated, the trunnions 6 are elastically deformed in the length direction based on the thrust load. Then, the inner surface of each of the trunnions 6, 6 and the outer surface of each of the outer races 30, 30
The distance from the surface becomes uneven. In addition, each trunnion 6, 6
Is elastically deformed into an arc shape in the longitudinal direction based on a thrust load applied to the intermediate portion in the longitudinal direction through the power rollers 8. Therefore, the distance between the inner surface and the outer surface is
It is large at the center in the length direction and small at both ends.

As described above, the thrust needle bearings 27, 27
In the case of the conventional structure, the thrust needle bearing 2
As the plurality of needles 33, 33 constituting 7, 27, those having the same outer diameter and length have been used. Because of this,
The thrust load is not uniformly applied to all the needles 33, 33, but is greatly applied to some of the needles 33, 33.
For example, in the case of the structure shown in FIG. 8 , a large thrust load acts on the needles 33, 33 arranged at both ends in the longitudinal direction (vertical direction in FIG. 8 ) of the inner surface of the trunnion 6,
Only a small thrust load acts on the needles 33, 33 arranged at the center in the longitudinal direction.

As a result, the load on the needles 33, 33 disposed at both longitudinal ends of the inner side surface of the trunnion 6 and the raceway surface facing the rolling surface of the needles 33, 33 increases, and these surfaces become large. And sufficient durability cannot be ensured, such as shortening the fatigue life of steel. The balls 29, 29 of the thrust ball bearing 26, which are the rolling elements of the thrust rolling bearing, and the outer ring 3
Since the contact load of 0 becomes large near both ends in the longitudinal direction of the trunnion 6, the fatigue life of the thrust ball bearing 26 as the thrust rolling bearing also becomes short. The toroidal-type continuously variable transmission of the present invention has been invented in view of the above-described circumstances.

[0025]

Means for Solving the Problems The toroidal type stepless of the present invention
The transmission, like the above-described conventional toroidal-type continuously variable transmission, has first and second disks concentrically and rotatably supported in a state where the inner surfaces thereof are opposed to each other, A trunnion that swings around a pivot axis that is twisted with respect to the central axis of the first and second disks, and a support shaft and a pivot shaft that are parallel and eccentric to each other,
The pivot shaft is rotatably supported by the trunnion by the support shaft, and the pivot shaft is rotatably supported around the pivot shaft and a displacement shaft protruding from the inner surface of the trunnion. In the state, the power roller sandwiched between the first and second disks, and provided alongside the outer surface of the power roller, while supporting the load in the thrust direction applied to the power roller, A thrust rolling bearing that allows rotation of the power roller, and is provided between an outer surface of an outer ring and an inner surface of the trunnion that constitute the thrust rolling bearing, and supports a thrust load applied to the outer ring from the power roller. A thrust needle bearing that allows the pivot shaft portion and the outer ring to swing about the support shaft portion. The inner surfaces of the first and second disks are Each section is a concave arc-shaped peripheral surface of the power roller is a spherical convex surface, the peripheral surface and the inner surface are in contact with each other.

In particular, in the case of the toroidal type continuously variable transmission of the present invention , the following conditions are satisfied. The outer diameters of the plurality of needles constituting the thrust needle bearing slightly differ depending on the positions of the needles. The outer diameter of each needle is large at a portion near the center in the longitudinal direction of the trunnion and small at portions near both ends in the longitudinal direction.

[0027]

[0028]

The toroidal-type continuously variable transmission of the present invention configured as described above has a similar operation to that of the above-described conventional toroidal-type continuously variable transmission, and is provided between the first disk and the second disk. The transmission of the rotational force is carried out by means of, and by changing the inclination angle of the trunnion, the rotational speed ratio between these two disks is changed.

In particular, in the case of the toroidal-type continuously variable transmission of the present invention, the thrust needle bearing provided between the inner surface of the trunnion and the outer surface of the outer ring constituting the thrust rolling bearing covers substantially the entire surface thereof. And a uniform thrust load is applied.

That is, in the case of the toroidal type continuously variable transmission of the present invention, the diameter of the needle is adjusted in accordance with the unevenness of the distance between the inner surface and the outer surface based on the elastic deformation of the trunnion. Changing. Therefore, only some of the needles do not stick between these two surfaces, and the thrust loads applied to the plurality of needles can be made uniform.
Further, the contact load between the rolling element of the thrust rolling bearing and the outer ring can be made uniform.

[0031]

[0032]

FIG. 1 shows an embodiment of the present invention . still,
A feature of the present invention is that a thrust load is uniformly applied to the plurality of needles 33, 33 (see FIG. 8 ) constituting the thrust needle bearing 27, the needles 33, 33, the members opposed to the needles 33, 33, and the thrust rolling. In order to improve the durability of the thrust ball bearing 26 as a bearing,
The point is that the diameters of the needles 33, 33 are devised in relation to the arrangement position. The structure and operation of the other parts are the same as those of a conventionally known toroidal-type continuously variable transmission, for example, as described above. Therefore, description of the same parts as those of the conventional structure is omitted, and the following description focuses on the features of the present invention.

The plurality of needles 33 constituting the thrust needle bearing 27 are arranged in ranges A, B, C and D shown by oblique lattices in FIG. Each range A to D
In the arrangement direction of the needles 33, 33, the direction of radiation centered on the center O of the support shaft 21 (see FIG. 5 ) of the displacement shaft 7 (this radiation coincides with the central axis of each needle 33, 33) Direction).

The outer diameters of the needles 33, 33 arranged in each of the ranges A to D are different for each range. The diameters of the needles 33 included in the same range are the same. That is, the needle 3 included in the range C located near the center in the length direction of the trunnion 6 (vertical direction in FIG. 1).
The diameters of the needles 33, 33 included in the range B slightly shifted to the end side are set to be the same as or slightly smaller than the needles in the range C. Further, a range A located at a portion near both ends in the length direction,
The diameter of the needles 33 included in D is made smaller (C ≧ B
> A, D). The extent to which the diameters of the needles 33 are different in each of the ranges A to D is determined in design according to the length and rigidity of the trunnion 6, the thrust load applied to the trunnion 6, and the like. However, even between the needles 33 having the most different diameters, the difference (for example, C-
A) is about several tens to several hundreds μm.

The thrust needle bearing 27 as described above is
Based on the elastic deformation of the trunnion 6, this trunnion 6
Inner surface and outer ring 30 of thrust ball bearing 26 (see FIG. 5 )
The diameters of the needles 33, 33 are changed in accordance with the distance between the needles 33 and 33 becoming uneven. Therefore, only some of the needles 33, 33 do not stick between these two surfaces, and the thrust load applied to the plurality of needles 33, 33 is made uniform.

[0036]

[0037]

[0038]

[0039]

The toroidal-type continuously variable transmission according to the present invention is constructed and operated as described above, so that the durability and reliability of the thrust needle bearing portion and the thrust rolling bearing are improved, and this thrust needle bearing is improved. In addition, the durability and reliability of a toroidal type continuously variable transmission incorporating a thrust rolling bearing can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a trunnion inner surface portion showing an embodiment of the present invention .

FIG. 2 is a side view showing a basic configuration of a conventionally known toroidal type continuously variable transmission in a state of maximum deceleration.

FIG. 3 is a side view showing a state at the time of maximum speed increase.

FIG. 4 is a cross-sectional view showing one example of a conventional specific structure.

FIG. 5 is a sectional view taken along line AA of FIG . 4 ;

FIG. 6 is a view of the thrust needle bearing incorporated in the conventional structure as viewed in the same direction as FIG.

FIG. 7 is an enlarged sectional view taken along line BB of FIG . 6 ;

FIG. 8 is a view similar to FIG. 6 , showing a thrust needle bearing manufactured according to a conventional structure.

[Explanation of symbols]

 Reference Signs List 1 input shaft 2 input side disk 2a inner surface 3 output shaft 4 output side disk 4a inner surface 5 pivot 6 trunnion 7 displacement shaft 8 power roller 8a peripheral surface 9 pressing device 10 cam plate 11 retainer 12 roller 13, 14 cam surface 15 Input shaft 16 Needle bearing 17 Flange 18 Output gear 19 Key 20 Support plate 21 Support shaft 22 Pivot shaft 23 Circular hole 24, 25 Needle bearing 26 Thrust ball bearing 27 Thrust needle bearing 28 Cage 29 Ball 30 Outer ring 31 Race 32 Holder 33 Needle 34a, 34b Ring 35a, 35b Projection 36 Drive Rod 37 Drive Piston 38 Drive Cylinder 39 Main Holder 40a, 40b Secondary Holder 41 Pocket

Claims (1)

(57) [Claims] 1. In a state where the inner side surfaces are opposed to each other,
First and second discs concentrically and rotatably supported, a trunnion swinging about a pivot that is twisted with respect to the central axis of the first and second discs, and a trunnion that is parallel to each other. And a displaceable shaft having an eccentric support shaft and a pivot shaft, rotatably supported by the trunnion by the support shaft, and projecting the pivot shaft from the inner surface of the trunnion. A power roller sandwiched between the first and second disks while being rotatably supported around the pivot shaft portion; and a power roller provided alongside an outer surface of the power roller. A thrust rolling bearing that allows the rotation of the power roller while supporting a load in the thrust direction applied to the power roller, and between an outer surface of an outer ring and an inner surface of the trunnion that constitute the thrust rolling bearing. And a thrust needle bearing that allows the pivot shaft portion and the outer ring to swing about the support shaft portion while supporting a thrust load applied to the outer ring from the power roller. The inner surface of each of the first and second disks is a concave surface having an arc-shaped cross section, the peripheral surface of the power roller is a spherical convex surface, and the peripheral surface and the inner surface are in contact with each other, and A toroidal type continuously variable transmission that satisfies the following conditions. The outer diameters of the plurality of needles constituting the thrust needle bearing slightly differ depending on the positions of the needles.
The outer diameter of each needle is large at a portion near the center in the longitudinal direction of the trunnion and small at portions near both ends in the longitudinal direction.