JP2000205362A - Troidal type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the durability of a needle bearing irrespective of elastic deformation of a disc 4 on output side based on load applied at the time of operation. SOLUTION: Proper crownings 59, 59 are applied in both end parts in the axial direction of each needle 54a, 54a constituting a needle bearing 16a. A crowning amount of each needle is 7 to 13% of a length in the axial direction from an end face in the axial direction of each needle 54a and 0.1 to 0.4% of an outside diameter of a central part in the axial direction of each needle 54a in a part close to the center in the axial direction. Edge load is not applied to an outer ring receway 57 provided on an inner peripheral face of a disc 4 on output side and an inner ring receway 56 formed on an outer peripheral face of an input shaft 15 even when the disc 4 on output side is elastically deformed. Consequently, it is possible to prevent the occurrence of damage such as early peeling on each face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A toroidal type continuously variable transmission according to the present invention is used, for example, as a transmission unit constituting a transmission for an automobile or as a transmission for various industrial machines.
Use each.

[0002]

2. Description of the Related Art The use of a toroidal type continuously variable transmission as schematically shown in FIGS. 8 and 9 has been studied, for example, as a transmission unit constituting a transmission for an automobile. This toroidal-type continuously variable transmission supports an input disk 2 concentrically with an input shaft 1 as disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 62-71465, and an output arranged concentrically with the input shaft 1. The output disk 4 is fixed to the end of the 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.

That is, these trunnions 6, 6 arranged at portions off the central axis of the two disks 2, 4 have the pivots 5, 5 on the outer surfaces of both ends, respectively, and the center of the two disks 2, 4 They are provided in a direction perpendicular to the direction of the axis and concentric with each other. In addition, the trunnions 6 and 6 support the base ends of the displacement shafts 7 and 7 at the intermediate portions thereof, and swing the trunnions 6 and 6 about the pivots 5 and 5 so that the respective displacements can be adjusted. The inclination angles of the shafts 7, 7 can be adjusted freely. Power rollers 8 are rotatably supported around the displacement shafts 7 supported by the trunnions 6 respectively. The power rollers 8, 8 are sandwiched between the inner surfaces 2a, 4a of the input and output disks 2, 4 facing each other. Each of the inner side surfaces 2a, 4a has a concave section obtained by rotating an arc around the pivot 5 as described above. Then, the peripheral surfaces 8a, 8a of the power rollers 8, 8, which are formed into spherical convex surfaces, are connected to the inner surfaces 2a, 4a.
a.

[0004] 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. It can be pressed freely. The pressing device 9 includes a cam plate 10 that rotates together with the input shaft 1, and a plurality (for example, four) of rollers 12, which are rotatably held by a holder 11. The cam plate 10
On one side surface (left side surface in FIGS. 8 and 9), a drive side cam surface 13 which is an uneven surface extending in the circumferential direction is formed, and the outer side surface of the input side disk 2 (right side surface in FIGS. 8 and 9). Has a driven side cam surface 14 having a similar shape. And
The plurality of rollers 12, 12 are rotatably supported about a radial axis 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, the driving-side cam surface 13 has a plurality of rollers 12, 12.
Is pressed against the driven cam surface 14 formed 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, 8, and at the same time, the input side disk is pressed based on the pressing between the driving side and driven side cam surfaces 13, 14 and the plurality of rollers 12, 12. 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the plurality of power rollers 8, 8, and the output side disk 4
, The fixed output shaft 3 rotates.

When the rotational speed ratio (speed change ratio) between the input shaft 1 and the output shaft 3 is changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, each of the pivots 5 The trunnions 6, 6 are swung in a predetermined direction as a center. The peripheral surfaces 8a, 8a of the power rollers 8, 8 are shown in FIG.
As shown in FIG. 5, the displacement shafts 7, 7 are inclined so as to abut against the central portion of the inner surface 2a of the input disk 2 and the outer peripheral portion of the inner surface 4a of the output disk 4, respectively. Conversely, when increasing the speed,
, Each of the trunnions 6 is swung in the opposite direction. The peripheral surface 8 of each of the power rollers 8
As shown in FIG. 9, the displacement shafts 7 a and 8 a abut against the outer peripheral portion of the inner surface 2 a of the input disk 2 and the central portion of the inner surface 4 a of the output disk 4, respectively. , 7 are tilted. If the inclination angle of each of the displacement shafts 7 is in the middle between FIGS. 8 and 9, an intermediate speed ratio can be obtained between the input shaft 1 and the output shaft 3.

FIGS. 10 to 11 show Japanese Utility Model Application No. 63-692.
1 shows an example of a more specific toroidal-type continuously variable transmission described in the microfilm of No. 93 (Japanese Utility Model Laid-Open No. 1-173552). The input side disk 2 and the output side disk 4 are provided around a cylindrical input shaft 15 around a needle bearing 1 corresponding to the radial bearing described in the claims.
It is rotatably supported via 6 and 16. As shown in detail in FIGS. 12 to 14, each of the needle bearings 16, 16 has a plurality of needles 54, 54, and a cage-shaped retainer for rotatably supporting these needles 54, 54. 55. The outer peripheral surface of the input shaft 15 is a cylindrical inner raceway 56, and the inner peripheral surfaces of the input and output disks 2, 4 are outer raceway 57.

The cam plate 10 is spline-engaged with the outer peripheral surface of the input shaft 15 at the end (left end in FIG. 10), and is prevented from moving away from the input disk 2 by the flange 17. I have. The cam plate 10 and the roller 1
A loading cam type pressing device 9 for rotating the input side disk 2 while pressing the input side disk 2 toward the output side disk 4 based on the rotation of the input shaft 15 by the rotation of the input shaft 15.
Is composed. The output side disk 4 has an output gear 1
8 are connected by keys 19, 19 so that the output side disk 4 and the output gear 18 rotate synchronously.

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. 10, and left and right directions in FIG. 11). 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 has a support shaft 21 and a pivot shaft 22, 22 which are parallel and eccentric to each other. Each of the support shaft portions 21, 21 is provided inside the above-mentioned circular hole 23, 23 with a radial needle bearing 24,
It is rotatably supported via 24. The power rollers 8, 8 are rotatably supported around the pivot shafts 22, via separate radial needle bearings 25, 25.

Note that the pair of displacement shafts 7 are provided at positions 180 ° opposite to the input shaft 15. or,
The direction in which the respective pivot shaft portions 22, 22 of the respective displacement shafts 7, 7 are eccentric with respect to the respective support shaft portions 21, 21 is the same as the rotation direction of the input side and output side disks 2, 4. In FIG. 11, the left and right directions are opposite. The eccentric direction is
The direction is substantially perpendicular to the direction in which the input shaft 15 is provided. Accordingly, the power rollers 8 are supported to be slightly displaceable in the direction in which the input shaft 15 is provided. As a result, the power rollers 8, 8 move in the axial direction of the input shaft 15 (see FIG. Even in the case of displacement in the left-right direction (the front-back direction in FIG. 11), this displacement can be absorbed without applying unreasonable force to the components.

Further, 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, thrust ball bearings 26, 26 and thrust needle bearings 27, 27 are provided. The thrust ball bearings 26 support rotation of the power rollers 8 while supporting the load applied to the power rollers 8 in the thrust direction. Each of such thrust ball bearings 26, 26 has a plurality of balls 29, 29, and each of these balls 2
Circular retainers 28, 2 that hold rolling rolls 9, 29 freely
8 and an annular outer ring 30. The inner raceway of each thrust ball bearing 26, 26 is on the outer surface of each power roller 8, 8 and the outer raceway is each of the outer races 30, 3
0 are formed on the inner surface.

The thrust needle bearings 27, 2
7 comprises a race 31, a retainer 32, and needles 33,33. Race 31 and cage 32 of these
And are slightly displaceable in the direction of rotation about the support shaft 21. Such thrust needle bearings 27, 27 are provided between the inner surfaces and the outer surfaces of the outer rings 30, 30 with the races 31, 31 abutting on the inner surfaces of the trunnions 6, 6, respectively. It is pinched. Such thrust needle bearings 27, 27
While supporting the thrust load applied to the outer races 30, 30 from the power rollers 8, 8, the respective pivot shafts 2 are supported.
2, 22 and the outer race 30, 30 are supported by the support shaft 2
Swinging around 1 and 21 is allowed.

Further, driving rods 36, 36 are provided at one end (the left end in FIG. 11) of each of the trunnions 6, 6, respectively.
And drive pistons 37, 37 are fixedly provided on the outer peripheral surface of the intermediate portion of each of the drive rods 36, 36. And
These drive pistons 37 are fitted in drive cylinders 38 in an oil-tight manner, respectively.

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 side 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 further, the output side disk 4
Is taken out from the output gear 18. Input shaft 15
When changing the rotation speed ratio between the output gear 18 and
The pair of drive pistons 37 are displaced in directions opposite to each other. The pair of trunnions 6, 6 are displaced in opposite directions with the displacement of the drive pistons 37, 37. For example, the lower power roller 8 in FIG. Power roller 8 on the left side of FIG.
Each is displaced. As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner surfaces 2a, 4a of the input disk 2 and the output disk 4 changes. I do. Then, with the change in the direction of the force, the trunnions 6 swing in opposite directions about the pivots 5 pivotally supported by the support plates 20. As a result, as shown in FIGS. 8 and 9 described above, the contact positions between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner surfaces 2a, 4a change, and the input shaft 15 The rotation speed ratio with the output gear 18 changes.

Incidentally, the input shaft 15 and the output gear 1 are
When transmitting the rotational force to the power rollers 8, the power rollers 8, 8 are displaced in the axial direction of the input shaft 15 based on the elastic deformation of the constituent members. Each of the displacement shafts 7, which pivotally supports 8, slightly rotates around each of the support shaft portions 21, 21. As a result of this rotation, the outer ring 3 of each of the thrust ball bearings 26, 26
The outer surfaces of the trunnions 6 and 6 are relatively displaced from each other. 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.

Further, in order to increase the torque that can be transmitted, as shown in FIGS. 15 and 16, two input disks 2A and 2B and two output disks 4 and 4 are provided around the input shaft 15a. A structure in which two input-side disks 2A and 2B and two output-side disks 4 and 4 are arranged in parallel with each other in the power transmission direction is also conventionally known. Each of the structures shown in FIGS.
An output gear 18a is supported around an intermediate portion of the output gear 18a so as to be freely rotatable with respect to the input shaft 15a. The output disks 4 are mounted on both ends of a cylindrical portion provided at the center of the output gear 18a. Have been combined. Needle bearings 16 and 16 are provided between the inner peripheral surface of each of the output disks 4 and 4 and the outer peripheral surface of the input shaft 15a, and these output disks 4 and 4 are arranged around the input shaft 15a. ,
The rotation with respect to the input shaft 15a and the input shaft 15
a is freely supported in the axial direction. The input side disks 2A and 2B are rotatably supported on both ends of the input shaft 15a together with the input shaft 15a. The input shaft 15a is rotationally driven by a driving shaft 51 via a loading device 9 of a loading cam type. The outer peripheral surface of the distal end of the drive shaft 51 (the left end in FIGS. 15 to 16) and the base end of the input shaft 15a (the right end in FIGS. 15 to 16).
A radial bearing 52 such as a sliding bearing or a needle bearing is provided between the bearing and the inner peripheral surface. Therefore, the drive shaft 51 and the input shaft 15a are arranged concentrically with each other.
They are combined so as to be slightly displaceable in the rotation direction.

However, the input side disk 2A (left side in FIGS. 15 to 16) has a rear surface (left surface in FIGS. 15 to 16) directly on the loading nut 39 (in the case of the structure shown in FIG. 16) or a large size. 1 through an elastic disc spring 45 (FIG. 1).
5, the input shaft 15a
In the axial direction (the left-right direction in FIGS. 15 and 16). On the other hand, the input side disk 2B opposed to the cam plate 10 is supported on the input shaft 15a by a ball spline 40 so as to be freely displaceable in the axial direction. Then, the rear surface of the input side disk 2B (FIG. 1)
5 to 16) and the front surface of the cam plate 10 (the left surface in FIGS. 15 to 16).
2 are provided in series with each other. Among them, the plate spring 41 is provided on the inner side surface 2a of each of the disks 2A, 2B, and 4,
It serves to apply a preload to a contact portion between the power roller 4a and the peripheral surfaces 8a of the power rollers 8,8. Further, the thrust needle bearing 42 plays a role of permitting relative rotation between the input side disk 2B and the cam plate 10 when the pressing device 9 is operated.

In the case of the structural example shown in FIG. 15, the output gear 18a is mounted on a partition wall 44 provided inside the housing 53 (FIG. 11) by a pair of angular ball bearings 43,4.
By 3, it is rotatably supported in a state where displacement in the axial direction is prevented. On the other hand, in the case of the structural example shown in FIG. 16, the displacement of the output gear 18a in the axial direction is free. As shown in FIGS. 15 and 16, the so-called double-cavity toroidal in which two input disks 2A and 2B and two output disks 4 and 4 are arranged in parallel with respect to the power transmission direction. The one or both input side disks 2A, 2A,
B is connected to the input shaft 1 by the ball splines 40 and 40a.
The reason for supporting the shaft 5a so that it can be displaced in the axial direction is as follows.
While completely rotating the two disks 2A and 2B, the two disks 2A and 2B are connected to the input shaft 15 based on the elastic deformation of the constituent members accompanying the operation of the pressing device 9.
This is to allow displacement in the axial direction with respect to a.

The ball splines 40 and 40a installed for the above-described purpose are provided on the inner diameter side ball spline grooves 46 formed on the inner peripheral surfaces of the input side disks 2A and 2B and on the outer peripheral surface of the intermediate portion of the input shaft 15a. The formed outer diameter side ball spline groove 47, and both of these ball spline grooves 46,
A plurality of balls 4 provided so as to be able to roll between 47
8, 48. As for the ball spline 40 for supporting the input disk 2B on the pressing device 9 side, a locking ring 50 is formed in a locking groove 49 formed in a portion of the inner peripheral surface of the input disk 2B near the inner surface 2a. Lock the
The plurality of balls 48, 48 are connected to the input side disk 2.
B is restricted from being displaced toward the inner side surface 2a. Further, the balls 48, 48 are prevented from falling out from between the inner diameter side and outer diameter side ball spline grooves 46, 47. In the structure shown in FIG. 15, a ball spline 40a for supporting the input disk 2A remote from the pressing device 9 has a portion near the tip of the input shaft 15a (a portion near the left end in FIG. 15). The locking ring 50a is locked in the locking groove 49a formed in the above-mentioned manner, thereby restricting the displacement of the plurality of balls 48, 48 toward the inner side surface 2a of the input side disk 2A.

[0020]

In the case of a conventional toroidal-type continuously variable transmission configured and operating as described above, the input shaft 1
Needle bearings 16 for supporting the output side disks 4 and 4 around the periphery of the shafts 5 and 15a so as to be freely rotatable and axially displaceable.
The durability of No. 16 was not always sufficient. The reason will be described below.

When the toroidal type continuously variable transmission is used as a transmission unit of a transmission for an automobile, the power transmitted from the engine to the input shafts 15 and 15a is transmitted from the input side disks 2, 2A and 2B to the power rollers 8 respectively. , 8 to the output side disks 4, 4. A traction portion for transmitting power between the power rollers 8, 8 and the output disks 4, 4, that is, the output disks 4, 4,
The contact portions between the inner side surfaces 4a, 4a and the peripheral surfaces 8a, 8a of the power rollers 8, 8 are present at a plurality of positions at equal intervals in the circumferential direction. Therefore, the radial component of the load applied to the inner surfaces 4a, 4a of the output disks 4, 4 based on the power transmission is canceled in the output disks 4, 4. Therefore, each of the needle bearings 16, 16
The radial load applied to the output disks 4 and 4
And only the weights of the output gears 18, 18a and the like fixedly connected to the output side disks 4, 4, respectively.

On the other hand, the needle bearings 16,
The operating speed of the needle bearings 16 for supporting the output disks 4 is the relative rotational speed between the output disks 4 and the input shafts 15a. Since the rotation directions of the output disks 4 and 4 and the input shafts 15 and 15a are opposite to each other,
For example, the rotation speed of the input shafts 15 and 15a is 4000 rpm.
When the gear ratio is 1, the above-mentioned needle bearings 1
The operating speeds of 6 and 16 are 8000 rpm (= 4000 rpm).
m. + 4000 rpm). When the reduction ratio is 0.5 (2
In the case of double speed, the operating speed of each of the needle bearings 16 is 12,000 rpm (= 4000 rpm + 80).
00 rpm), and in the case of 2.0 (reduced to 1/2), 6000 rpm (= 4000 rpm + 2000)
rpm).

As long as the load applied to each of the needle bearings 16 and 16 is of a level commensurate with the above-described weight, even if the operating speed is at the above-described level, each of these needle bearings 1
Rolling fatigue life of 6, 16 does not matter. However, according to experiments by the present inventors, when the input torque (the drive torque of the input shafts 15 and 15a) is large, and the transmission between the input disks 2, 2A and 2B and the output disks 4 and 4, If the operation is performed for a long time in the deceleration state, the inner peripheral surfaces of the output disks 4 and 4 and the input shaft 1
Needle bearings 16 provided between the outer peripheral surfaces of the needle bearings 5 and 15a,
No. 16, premature peeling occurred.

The present inventors have studied the cause of such early peeling and found that the output side disks 4 and 4 are repeatedly elastically deformed due to power transmission. That is, in the case of a structure in which two power rollers 8 are provided for each capacity, the inner surfaces 4a, 4a,
a contacts the peripheral surfaces 8a, 8a of the power rollers 8, 8 at two positions on the opposite side in the circumferential direction. The large thrust load generated by the pressing device 9 during power transmission causes
The position is strongly pushed in the axial direction. As a result, the output disks 4, 4 are elastically deformed. In particular, FIGS.
As shown in FIG. 2, the peripheral surfaces 8a of the power rollers 8, 8 are connected to the output disks 4, 2A, 2B to reduce the speed between the output disks 4, 4. In a state where the inner disks 4 are in contact with the inner diameter portions of the inner side surfaces 4a, 4a, a large moment is applied to the output side disks 4, 4 as shown by arrows in FIG.

The output-side disks 4, 4 are connected to the needle bearings 16, 16 as fulcrums in FIGS.
As shown in an exaggerated manner in FIG. The amount of elastic deformation generated by such a mechanism is particularly large on the inner diameter side of the output-side disks 4 and 4, particularly at the small-diameter end portion (the inner end surface 4 a side open end portion) where the thickness is small. The cross-sectional shape of the center hole 58 of each of the output side disks 4 and 4 is the same as that of the above-described 2
An elliptical shape, in which the direction of the straight line connecting the locations is the major axis direction. Along with this, a portion in which the position in the circumferential direction is shifted by 90 degrees with respect to the long diameter direction becomes the short diameter direction of the elliptical shape, and is formed by the inner circumferential surfaces of the center holes 58 of the output side disks 4 and 4. The configured outer raceway 57 and the input shaft 1
The distance between the inner ring raceway 56 provided on the outer peripheral surface of each of the inner and outer races 5 and 15a is reduced. In addition, the distance between these two tracks 57 and 56 is not uniform in the axial direction, as shown exaggeratedly in FIG. That is, the inner surface 4a of each of the output side disks 4, 4,
The portion becomes narrower at the portion (the left portion in FIG. 22) closer to 4a. In the portion where the distance between the two raceways 57, 56 is narrow, the needles 54, 54 constituting the needle bearings 16, 16 are strongly pushed between the inner raceway 56 and the outer raceway 57. It is in a state of being crushed. As a result,
Excessive surface pressure based on the edge load is applied to portions of the inner raceway 56 and the outer raceway 57 that face the axial ends of the rolling surfaces of the needles 54, 54, thereby causing early separation or the like on the portions. This can cause damage.

When such damage occurs, the noise and vibration generated at the needle bearing 16 are increased, so that not only the toroidal type continuously variable transmission itself incorporating the needle bearing 16 but also the toroidal type continuously variable transmission is used. The sound and vibration of the entire transmission incorporating the transmission will increase.
And, it has a bad influence on the riding comfort performance of the vehicle equipped with this transmission. Further, when the strip generated due to the separation of the raceway surface is caught in the traction portion transmitting power, the surface pressure becomes excessive at the portion, and both the input side and the output side disks constituting the traction portion are formed. 2,
2A, 2B, 4 inner surface 2a, 4a and power roller 8,
It also causes damage such as premature peeling on the peripheral surfaces 8a, 8a. Further, the small pieces may cause clogging of the strainer or the filter, resulting in a decrease in the discharge flow rate of the pump for supplying the lubricating oil, resulting in poor lubrication, and a possibility of shortening the life of other parts. The input-side disk unit for a toroidal-type continuously variable transmission according to the present invention has been invented in view of such circumstances.

[0027]

An input side disk unit for a toroidal type continuously variable transmission according to the present invention has an input shaft rotatable and rotatable, similarly to the above-mentioned conventional toroidal type continuously variable transmission. An input disk supported concentrically with the input shaft and rotatably supported with the input shaft; and a radial bearing around the input shaft rotatable with respect to the input shaft. An output disk provided with its side surfaces facing each other, and a twist position which does not intersect with the central axes of both the input and output disks, but which is at a right angle to the direction of the central axes of these two disks. A plurality of trunnions swinging about a pivot axis, and a displacement shaft supported at a middle portion of each of the trunnions so as to protrude from the inner surface of each of the trunnions; Inner surface arranged on the side and the input side of the trunnion, while being held between the output side disks, and a power roller which is rotatably supported around said displacement shafts. The inner surfaces of the input and output disks are arc-shaped concave surfaces in cross section, and the peripheral surface of the power roller is a spherical convex surface. Abut each other.

In particular, in the toroidal-type continuously variable transmission according to the present invention, the radial bearing is a needle bearing, and a plurality of needles constituting the needle bearing are crowned at both ends in the axial direction. I have. The crowning amount of each needle is 7 to 13% of the axial length from the axial end face of each needle toward the center in the axial direction, and 0.1% of the outer diameter of the central portion in the axial direction of each needle.
~ 0.4%.

[0029]

The toroidal-type continuously variable transmission of the present invention constructed as described above has a rotational force between the input side disk and the output side disk based on the same operation as the above-mentioned conventional toroidal type continuously variable transmission. 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, an appropriate amount of crowning is applied to each needle constituting a needle bearing for rotatably supporting the output side disk with respect to the input shaft. Therefore, regardless of the elastic deformation of the output side disk, it is possible to effectively prevent an excessive surface pressure from being applied to the components of the needle bearing.

[0031]

1 to 5 show an example of an embodiment of the present invention. The feature of the present invention is that the input shaft 15
And a needle bearing 16a for rotatably supporting the output side disk 4 around an intermediate portion of the needle bearing 16a. Since the structure and operation of the other parts are the same as those of the above-described conventional structure, overlapping illustration and description will be omitted or simplified, and the following description will focus on features of the present invention.

The needle bearing 16a has a plurality of needles 54a, 54a, and each of the needles 54a, 54a can be freely rolled, similarly to the needle bearing incorporated in the conventional toroidal type continuously variable transmission described above. And a cage-shaped retainer 55 for supporting. And the input shaft 1
The outer peripheral surface of the intermediate portion of the disk 5 is a cylindrical inner raceway 56, and the inner peripheral surface of the center hole 58 of the output side disk 4 is an outer raceway 57.

In particular, in the case of the toroidal type continuously variable transmission of the present invention, the plurality of needles 54a, 54a are crowned 59, 59 at both ends in the axial direction as shown in detail in FIG.
Has been given. The crowning amount δ ₅₉ of each of the needles 54a, 54a, that is, the respective crowning ₅₉ , ₅₉
The distance by which the outer peripheral surface of the outer peripheral surface is displaced inward in the diametrical direction from the original cylindrical surface (assuming that the cylindrical portion 60 at the axial center portion is directly extended) is regulated as follows. First, as a premise, the needles 54a, the axial length of 54a L _54a, the outer diameter of the cylindrical portion 60 and D _60, the needles 54a, from the end face of 54a to the measuring position of the crowning amount [delta] ₅₉ Is L ₅₉ . Then, the distance L ₅₉ up to this measurement positions, and 7-13% of the axial length _{L 54a {L 59 = (0.07~0.13} ) L
_54a ｝. Under such conditions, the crowning amount δ
_59, and 0.1 to 0.4% of the outer diameter D ₆₀ of the cylindrical portion _{60 {δ 59 = (0.001~0.004)} D 60}.

As described above, in the case of the toroidal type continuously variable transmission of the present invention, the needle bearing 16a for rotatably supporting the output side disk 4 at the intermediate portion of the input shaft 15 is provided.
Are crowned 59, 59 in an appropriate amount. Therefore, the distance between the inner raceway 56 and the outer raceway 57 constituting the needle bearing 16a, which is based on the elastic deformation of the output disk 4 due to a large load generated during operation of the toroidal type continuously variable transmission, is not affected. In addition, it is possible to effectively prevent an excessive surface pressure from being applied to the components of the needle bearing 16a.

That is, during operation of the toroidal type continuously variable transmission, the output side disk 4 is attached to the peripheral surfaces 8 of the power rollers 8, 8.
a, 8a (FIGS. 8 to 11 and FIGS. 15 to 18), based on a large load applied to two positions on the opposite side in the diametrical direction, FIG.
It elastically deforms as shown exaggeratedly in FIGS. Thus, even when the output side disk 4 is elastically deformed and the distance between the inner raceway 56 and the outer raceway 57 becomes uneven, the axial ends of the needles 54a, 54a and the inner raceway 56
Also, there is no contact between the outer ring raceway 57 and the occurrence of early peeling based on the edge load.

As described above, in the case of the present invention, the occurrence of the edge load is prevented by applying appropriate crownings 59, 59 to both ends of the needles 54a, 54a constituting the needle bearing 16a in the axial direction. Thus, the durability of the needle bearing 16a can be improved. That is, in the case of the present invention, the appropriate amount of crowning 59, 59 is applied to each of the needles 54a, 54a.
When the outer raceway 57 formed by the inner peripheral surface of the outer ring raceway 57 is elastically deformed, the respective needles 54a, 54a held by the retainer 55 slightly change the posture, and the rolling surfaces of the needles 54a, 54a And the inner ring raceway 56 is imitated. Then, the contact state between the rolling surfaces of the needles 54a, 54a and the inner ring raceway 56 and the outer ring raceway 57 is set to an appropriate contact state, so that the contact pressure of the contact portion is prevented from excessively increasing.

If the crowning amount δ ₅₉ of the crowning _{59, 59} applied to both ends of the needles 54 a, 54 a in the axial direction is too small, edge load cannot be sufficiently prevented, and the needle bearing 16 a Cannot sufficiently improve the durability. Conversely, if the crowning amount δ ₅₉ is too large, the needle bearing 16
a of the power rollers 8 supported by the needles 54a, 54a and the needle bearings 16a. As a result, an edge load is easily generated, and damage such as early peeling is easily caused. Moreover,
Since the output side disk 4 rotates at a high speed in a state where it is tilted as compared with the original position and transmits power, noise and vibration generated during operation of the toroidal type continuously variable transmission are increased. As a result, the entire transmission generates loud noises and vibrations from the transmission unit portion of the toroidal-type continuously variable transmission, which adversely affects the riding comfort of an automobile equipped with the transmission. On the other hand, in the case of the present invention, since the above-mentioned crowning amount δ ₅₉ is regulated within the above range, it is possible to effectively prevent the generation of the edge load and to prevent the inclination of the power roller 8 during operation.

[0038]

EXAMPLE An experiment conducted by the present inventor to limit the above-mentioned crowning amount δ ₅₉ to the above-mentioned range will be described. In the experiment, a deceleration durability test using a motor dynamo was performed on two types of large and small toroidal type continuously variable transmissions. Among them, a large toroidal type continuously variable transmission has a cavity diameter D ₀ (trunnion 6,
6. The distance between the central axes of the pivots 5 and 5 provided at both ends of 6. See FIG. ) Used a 130 mm double-cavity toroidal type continuously variable transmission. The operating conditions at the time of the test were such that the rotation speed of the input side disks 2A and 2B was set to 4000 r.
pm, the input torque was 300 Nm, and the reduction ratio was 2.0 (the rotation speed of the output disk 4 was の of the rotation speed of the input disks 2A and 2B). The size of the needle bearing 16a is determined by setting the diameter of the inscribed circle of each needle 54a, 54a to 28.
mm, the diameter of the circumscribed circle was 36 mm (the outer diameter of the cylindrical portion 60 of each needle 54a = 4 mm), and the axial length L _54a was 7.8 mm.

Under the above conditions, each of the above rollers 54a
Changing variety of crowning amount δ ₅₉ (crowning amount δ ₅₉
The in the parameter), performs experiments to know the durability of the needle bearings 16a, grasped a proper value as the crowning amount [delta] _59. Prior to performing such a deceleration endurance test, an FEM calculation is used to determine the magnitude of the load applied to the output side disk 4 from the power rollers 8 during operation of the toroidal type continuously variable transmission. the calculated deformation amount of 4, the deformation amount was reflected in the crowning amount [delta] _59. The target time of the deceleration endurance test is set to 2
0 hours. The value of 20 hours is a numerical value which is one of the standards of durability as the life of the transmission unit of the vehicle transmission. The results of the experiments performed in this way are shown in the following Table 1 and FIG.

[0040]

[Table 1]

The cavity diameter D ₀ is 104 mm.
The same deceleration endurance test was performed on a small single-cavity toroidal type continuously variable transmission. In this case, the rotation speed of the input side disk 2 is 4000 rpm,
The input torque was 60 Nm and the reduction ratio was 2.0. The dimensions of the needle bearing 16a are as follows: the diameter of the inscribed circle of each needle 54a is 20 mm, and the diameter of the circumscribed circle is 26 mm (needle 54a
Outer diameter of the cylindrical portion 60 of 3 mm), and the axial length L _54a is 1
It was 3.8 mm. It should be noted that the axial length in the case of a small size is larger than the axial length in the case of a large size,
Based on the existence of a spline portion provided at a connection portion between the output gear 18a and the output side disks 4, 4,
This is because the length of each needle bearing 16a cannot be increased. The results of the experiments performed in this way are shown in the following Table 2 and FIG.

[0042]

[Table 2]

From the results of these experiments, the needle 54a
When the outer diameter of the cylindrical portion 60 is 4 mm, the crowning amount δ
_{When 59} is 0.004 mm to 0.016 mm, 3
In the case of mm, it was found that when the crowning amount δ ₅₉ was 0.003 mm to 0.012 mm, the desired durability could be obtained. In each of these cases, the ratio of the crowning amount δ ₅₉ for obtaining sufficient durability to the outer diameter D ₆₀ of the cylindrical portion 60 of the needle 54a is 0.1% or more and 0.4% or less. In this case, the measurement position of the crowning amount δ ₅₉ was set at a position closer to the axial center by 7 to 13% from the end face of each needle 54 a with respect to the axial length L _{54 a} of each needle 54 a. . The measurement point in the actual deceleration durability test described above is a position (10.3%) at 0.8 mm from the end face when the axial length L _54a is 7.8 mm (outer diameter = 4 mm). When the axial length _L54a was 13.8 mm (outer diameter = 3 mm), the position was set at 1.4 mm from the end face (10.1%).

Incidentally, of the axial length L _54a of 7.8 mm (outer diameter = 4 mm), the experiment No. D is located 1.0 mm from the end face of each needle 54a (12.8%)
Crowning amount [delta] ₅₉ is 0.008mm (0.2%), crowning amount [delta] ₅₉ at the position of 0.55mm from the end face of each needle 54a (7.1%) of the 0.011mm
(0.28%), and any portion satisfied the conditions defined in the claims. Also, the axial length L _54a is 1
Experiment No. out of 3.8 mm (outer diameter = 3 mm). In the case of D, the crowning amount δ ₅₉ at a position (13.0%) 1.8 mm from the end face of each needle 54a is 0.006 mm.
(0.2%) from the end face of each needle 54a.
The crowning amount δ ₅₉ at the position of 0 mm (7.2%) is 0.1.
008 mm (0.27%), and any portion satisfied the conditions defined in the claims.

[0045]

Since the present invention is constructed and operates as described above, the toroidal-type continuously variable transmission can be provided with excellent durability and can contribute to the practical use of the toroidal-type continuously variable transmission.

[Brief description of the drawings]

FIG. 1 is an essential part cross-sectional view showing an example of an embodiment of the present invention in a state where an output side disk is elastically deformed.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a central portion of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 2;

FIG. 5 is a partially enlarged sectional view of a needle bearing.

FIG. 6 is a diagram showing the results of a first experiment conducted to find out the relationship between the crowning amount and the durability of the radial needle bearing.

FIG. 7 is a diagram showing the results of the second experiment.

FIG. 8 is a side view showing a basic configuration of a conventionally known toroidal-type continuously variable transmission in a state of maximum deceleration.

FIG. 9 is a side view showing a state at the time of maximum speed increase.

FIG. 10 is a sectional view showing a first example of a conventional specific structure.

FIG. 11 is a sectional view taken along the line CC of FIG. 10;

FIG. 12 is a view similar to FIG. 1, showing a conventional structure.

FIG. 13 is a sectional view taken along the line DD in FIG. 12;

FIG. 14 is an enlarged view of the center of FIG. 13;

FIG. 15 is a partial cross-sectional view showing a second example of a conventional specific structure.

FIG. 16 is a partial cross-sectional view showing the third example.

FIG. 17 is a cross-sectional view for explaining a load applied to each power roller during operation of a structure similar to the structure shown in FIG. 10;

18 is a cross-sectional view for explaining a load applied to each power roller during operation of a structure similar to the structure shown in FIG.

19 is a cross-sectional view of a main part of the conventional structure shown in FIG. 12 in a state where a power roller is elastically deformed.

FIG. 20 is a sectional view taken along line EE of FIG. 19;

FIG. 21 is an enlarged view of the center of FIG. 20;

FIG. 22 is a sectional view taken along line FF of FIG. 20;

[Explanation of symbols]

 Reference Signs List 1 input shaft 2, 2A, 2B 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 drive Side cam surface 14 Driven cam surface 15, 15a Input shaft 16, 16a Needle bearing 17, 17a Flange 18, 18a Output gear 19 Key 20 Support plate 21 Support shaft 22 Support shaft 23 Round hole 24 Radial needle bearing 26 Thrust Ball Bearing 27 Thrust Needle Bearing 28 Cage 29 Ball 30 Outer Ring 31 Race 32 Cage 33 Needle 34 Assembly Jig 35 Through Hole 36 Drive Rod 37 Drive Piston 38 Drive Cylinder 39 Loading Nut 40, 40a Ball Spline 41 Plate Spring 42 Thrust needle shaft 43 Angular Ball Bearing 44 Partition Wall 45 Disc Spring 46 Inner Ball Spline Groove 47 Outer Ball Spline Groove 48 Ball 49, 49a Lock Groove 50, 50a Lock Ring 51 Drive Shaft 52 Radial Bearing 53 Housing 54, 54a Needle 55 Cage 56 Inner raceway 57 Outer raceway 58 Center hole 59 Crowning 60 Cylindrical part

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Goto 1-50-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term in NSK Ltd. (reference) 3J051 AA03 BA03 BB01 BD02 BE08 ED20 FA02 3J101 AA14 AA24 AA32 AA42 AA52 AA62 AA72 BA02 FA31 GA11

Claims (1)

[Claims] An input shaft rotatably driven, an input disk concentric with the input shaft and rotatably supported with the input shaft, and a radial bearing surrounding the input shaft, An output disk provided rotatably and with its inner surface and the inner surface of the input disk facing each other, and the center axis of both the input and output disks does not intersect, but does not intersect. A plurality of trunnions swinging about a pivot at a twist position which is a position perpendicular to the direction of the center axis of the disc;
A displacement shaft supported at a middle portion of each of the trunnions so as to protrude from the inner surface of each of the trunnions, and disposed on the inner surface side of each of the trunnions and sandwiched between the input side and the output side disks. A power roller rotatably supported around each of the displacement axes,
The inner surfaces of both the input and output disks are arc-shaped concave surfaces, and the peripheral surface of the power roller is a spherical convex surface. In the toroidal type continuously variable transmission that is in contact, the radial bearing is a needle bearing, and a plurality of needles forming the needle bearing are crowned at both ends in the axial direction. The amount of crowning is 7 to 13% of the axial length from the axial end face of each of these needles to the center in the axial direction, and 0.1 to 0.4% of the outer diameter of the axially central portion of each of these needles. A toroidal type continuously variable transmission characterized by the following: