JPH08240252A - Toroidal type continuously variable transmission - Google Patents

Abstract

PURPOSE: To prevent excessive bearing pressure from acting on the rolling surface of a needle to form a thrust needle bearing and at the same time, prevent a needle from dropping from the pocket of a cage. CONSTITUTION: A thrust ball bearing is used to bear a thrust load acting on a power roller. A thrust needle bearing 27c allows the displacement of the outer ring of the thrust ball bearing relative to a trunnion 6. Also, a projection 54 formed on the cage 48 of the bearing 27c is engaged to the recess 56 of the trunnion 6, thereby restricting the displacement variable of the cage 48, and preventing needles 33 and 33 from being derailed from a race 31b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The toroidal type continuously variable transmission according to the present invention is used, for example, as a transmission for automobiles or as a transmission for various industrial machines.

[0002]

2. Description of the Related Art As a transmission for an automobile, for example, FIG.
The use of a toroidal type continuously variable transmission as schematically shown in 16 has been studied. This toroidal type continuously variable transmission is
For example, as disclosed in Japanese Utility Model Laid-Open No. 62-71465, an output shaft which is concentric with the input shaft 1 and supports an input side disc 2 which is a first disc, and which is arranged concentrically with the input shaft 1. The output side disk 4, which is a second disk, is fixed to the end portion of 3. Inside the casing in which the toroidal type continuously variable transmission is housed, there are provided trunnions 6 and 6 which swing around a pivot shaft 5 and 5 which are twisted with respect to the input shaft 1 and the output shaft 3. .

The trunnions 6, 6 are provided with the pivots 5, 5 on the outer surfaces of both ends. Further, the base ends of the displacement shafts 7, 7 are supported on the central portions of the trunnions 6, 6, and the trunnions 6, 6 are swung about the pivot shafts 5, 5, so that the displacement shafts 7, 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. And each power roller 8, 8
Are sandwiched between the input side and output side disks 2 and 4.

The inner surfaces 2a, 4a of the input-side and output-side disks 2, 4 facing each other have a cross-section of a concave surface obtained by rotating an arc about the pivot 5. The peripheral surfaces 8a, 8a of the power rollers 8, 8 formed in the spherical convex surface are in contact with the inner side surfaces 2a, 4a.

A loading cam type pressing device 9 is provided between the input shaft 1 and the input side disk 2, and the input side disk 2 is directed toward the output side disk 4 by the pressing device 9 and elastically. Pressing. This pressing device 9
Is a cam plate 10 that rotates together with the input shaft 1, and a retainer 11.
A plurality of (for example, four) rollers 12 held by
It is composed of 12 and. On one side surface (left side surface of FIGS. 15 to 16) of the cam plate 10, there is formed a cam surface 13 which is a concavo-convex surface extending in the circumferential direction, and the outer surface of the input side disk 2 (right side of FIGS. 15 to 16). Surface), the same cam surface 14
Is formed. Then, the plurality of rollers 12, 1
2 is rotatably supported about an axis in the radial direction with respect to the center of the input shaft 1.

When the toroidal type continuously variable transmission constructed as described above is used, when the cam plate 10 rotates as the input shaft 1 rotates, the cam surface 13 causes the plurality of rollers 12, 1 to rotate.
2 is pressed against the cam surface 14 on the outer surface of the input side 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, based on the pressing force between the pair of cam surfaces 13, 14 and the plurality of rollers 12, 12. The input side disk 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the plurality of power rollers 8, 8.
The output shaft 3 fixed to the output side disk 4 rotates.

When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6, 6 centering on the pivot shafts 5, 5 are used.
As shown in FIG. 15, the peripheral surfaces 8a, 8a of the power rollers 8, 8 are moved toward the center of the inner side surface 2a of the input side disk 2 and the outer peripheral side of the inner side surface 4a of the output side disk 4. The displacement shafts 7, 7 are tilted so as to abut with and respectively.

On the other hand, when increasing the speed, the trunnions 6, 6 are swung so that the peripheral surfaces 8a, 8a of the power rollers 8, 8 are located inside the input side disk 2 as shown in FIG. The outer peripheral portion of the side surface 2a and the inner side surface 4 of the output side disk 4
The displacement shafts 7, 7 are tilted so that they are brought into contact with the central portions of a. If the inclination angles of the displacement shafts 7, 7 are set in the middle between FIGS. 15 and 16, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.

Further, FIGS. 17 to 18 show Japanese Utility Model Application No. 63-69.
1 shows a more specific toroidal type continuously variable transmission described in a microfilm of No. 293 (Actual Kaihei No. 1-173552). The input side disk 2 and the output side disk 4 are rotatably supported around a circular tubular 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 (the left end portion in FIG. 17) of the input shaft 15, and is prevented from moving in the direction away from the input side disk 2 by the collar portion 17. The cam plate 10 and the rollers 12, 12 constitute a loading cam type pressing device 9. The pressing device 9 rotates 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. An output gear 18 is connected to the output side disk 4 by keys 19 and 19 so that the output side disk 4 and the output gear 18 rotate in synchronization with each other.

Both ends of the pair of trunnions 6, 6 are supported by the pair of support plates 20, 20 so as to be swingable and displaceable in the axial direction (front and back directions in FIG. 17, left and right directions in FIG. 18). There is. The displacement shafts 7, 7 are supported by the circular holes 23, 23 formed in the intermediate portions of the trunnions 6, 6. Each displacement shaft 7, 7 has a support shaft portion 21, 21 and a pivot shaft portion 22, 22 which are parallel to each other and are eccentric. Of these, the support shaft portions 21, 21 are connected to the circular holes 2
Inside of 3, 23, via needle bearings 24, 24,
It is rotatably supported. Also, each of the pivot shaft portions 22, 2
2 around the power rollers 8, 8 and another needle bearing 2
It is rotatably supported via 5, 25.

The pair of displacement shafts 7, 7 are provided at positions opposite to the input shaft 15 by 180 degrees. or,
The directions in which the pivot shafts 22, 22 of the displacement shafts 7, 7 are eccentric with respect to the support shafts 21, 21 are the input side,
The rotation directions of the output side disks 2 and 4 are the same (left and right opposite directions in FIG. 18). The eccentric direction is a direction substantially orthogonal to the disposing direction of the output shaft 15. Therefore, the power rollers 8, 8 are supported so as to be slightly displaceable in the arrangement direction of the input shaft 15. As a result, due to dimensional accuracy and elastic deformation of components,
Even if the power rollers 8, 8 tend to be displaced in the axial direction of the input shaft 15, the displacement can be absorbed without applying an unreasonable force to each component.

Between the outer surface of each of the power rollers 8 and 8 and the inner surface of the intermediate portion of each of the trunnions 6, 6, there are thrust ball bearings 26, in order from the outer surface of the power rollers 8, 8. 26 and thrust needle bearings 27, 27 are provided. Of these, the thrust ball bearings 26, 26 support the loads in the thrust direction applied to the power rollers 8, 8 while allowing the power rollers 8, 8 to rotate. Such thrust ball bearings 26, 26 have a plurality of balls 29, 29 and balls 29, 2 respectively.
An annular retainer 28, 28 for holding 9 in a rollable manner,
It is composed of an annular outer ring 30, 30. The inner ring races of the thrust ball bearings 26, 26 are formed on the outer side surfaces of the power rollers 8, 8 and the outer ring races are formed on the inner side surfaces of the outer rings 30, 30 respectively.

The thrust needle bearings 27, 27 are also provided.
Is a race 31 and a retainer 3 as detailed in FIGS.
2 and needles 33, 33. Of these, the race 31 and the cage 32 are combined so as to be slightly displaceable in the rotational direction. Further, the race 31 and the retainer 32 protrude outward in the diametrical direction from circular ring portions 34a and 34b centering on the pivot shaft portion 22 and partial outer peripheral edges of the circular ring portions 34a and 34b. It has protrusions 35a and 35b.

Such thrust needle bearings 27, 27
With the races 31 and 31 in contact with the inner side surfaces of the trunnions 6 and 6, the inner side surfaces and the outer ring 3 are
It is sandwiched between the outer surface of 0 and 30. In addition, the arrangement direction of each of the projecting portions 35a and 35b is the same as that of the supporting shaft portion 21,
The eccentric directions of the pivot shaft portions 22, 22 with respect to 21 are matched. Such thrust needle bearings 27, 27 are
While supporting the thrust load applied to the outer rings 30, 30 from the power rollers 8, 8, the pivot shaft portion 22,
22 and the outer rings 30 and 30 are the support shaft portions 21 and 21.
Allows swinging around.

Further, drive rods 36, 36 are provided at one end portions (the left end portions in FIG. 18) of the trunnions 6, 6 respectively.
And drive pistons 37, 37 are fixedly provided on the outer peripheral surfaces of the intermediate portions of the drive rods 36, 36. Then, the drive pistons 37, 37 are respectively connected to the drive cylinder 3
8 and 38 are oil-tightly fitted.

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 the rotation of the output side disk 4 is taken out from the output gear 18.

When the rotation speed ratio between the input shaft 15 and the output gear 18 is changed, the pair of drive pistons 37,
37 is displaced in opposite directions. As the drive pistons 37, 37 are displaced, the pair of trunnions 6,
6 are displaced in the opposite directions, for example, the lower power roller 8 in FIG. 18 is displaced to the right side in FIG. 18, and the upper power roller 8 in FIG. 18 is displaced to the left side in FIG. As a result,
The peripheral surfaces 8a, 8a of each of the power rollers 8, 8 and the inner side surfaces 2a, 4 of the input side disk 2 and the output side disk 4, respectively.
The direction of the tangential force acting on the contact portion with a changes. The trunnions 6, 6 are pivotally supported by the support plates 20, 20 in accordance with the change in the direction of the force.
It swings in directions opposite to each other with 5 as the center.

As a result, as shown in FIGS. 15 to 16, the contact positions between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner side surfaces 2a, 4a are changed, and the input power is changed. The rotational speed ratio between the shaft 15 and the output gear 18 changes.

For example, when the torque to be transmitted fluctuates and the amount of elastic deformation of the components changes, the displacement shafts 7, 7 rotate slightly about the support shafts 21, 21. Then, the power rollers 8, 8 are made to follow the inner side surfaces 2a, 4a of the both disks 2, 4. As a result of this rotation, the outer ring 30 of each thrust ball bearing 26, 26,
The outer side surface of 30 and the inner side surfaces of the trunnions 6, 6 are relatively displaced. Since the thrust needle bearings 27, 27 are present between the outer side surface and the inner side surface, the force required for this relative displacement is small. Therefore, as described above, the force for causing the power rollers 8, 8 to follow the inner side surfaces 2a, 4a can be small.

In the case of the toroidal type continuously variable transmission constructed and operated as described above, the durability of the outer ring 30 constituting the thrust ball bearing 26 is not always sufficient, and the toroidal type continuously variable transmission is used as a transmission for automobiles. It has been found by the study of the present inventors that this point needs to be improved in order to put into practical use. The reason for this is that the thrust needle bearing 27 that is configured to include the race 31 and the retainer 32 having the shapes shown in FIGS. 19 to 20 and that is sandwiched between the outer ring 30 of the thrust ball bearing 26 and the inner surface of the trunnion 6 is provided. This is because the thrust load applied to the outer ring 30 via the thrust ball bearing 26 cannot always be supported sufficiently.

That is, the thrust needle bearing 27 incorporated in the conventional toroidal type continuously variable transmission has the outer ring 30.
The purpose is to smooth the relative displacement between the trunnion 6 and the trunnion 6, and no consideration has been given to backing up the outer ring 30 against the thrust load. Therefore, when the cage 32 having the shape as shown in FIG. 19 and the outer ring 30 are overlapped with each other, a part of the outer ring 30 projects diametrically outward from the outer peripheral edge of the cage 32. The part of the outer ring 30 protruding in this way cannot be supported by the needles 33 held by the retainer 32.

On the other hand, the outer ring 30 has a plurality of balls 29 which form the thrust ball bearing 26 together with the outer ring 30.
By 29, a thrust load is applied over the entire circumference.
Therefore, bending stress is applied to the outer ring 30 by the thrust load applied to the above portion and the thrust load applied to the remaining portion, centering on the boundary between these portions and the remaining portion. In the case of a toroidal type continuously variable transmission used as a transmission for automobiles, such bending stress is considerably large, and moreover, it is repeatedly applied as the plurality of balls 29, 29 revolve. Therefore, the outer ring 30 is likely to be cracked or damaged such as peeling of the outer ring raceway surface, and the durability of the toroidal type continuously variable transmission is insufficient.

For example, according to an experiment conducted by the present inventor using thrust needle bearings according to the conventional structure shown in FIGS. 19 to 20, the outer ring raceway formed on the inner side surface of the outer ring 30 is prematurely peeled, Vibration occurred in the thrust ball bearing 26 portion. The thrust needle bearing used in the experiment is
As shown in FIG. 21, it has a ring-shaped main cage 39 and arc-shaped sub cages 40a and 40b.
a and 40b each have a plurality of needles 33, 33
Is rotatably held. Of these, the main retainer 39 is arranged around the support shaft portion 21 that constitutes the displacement shaft 7, and the sub-retainers 40a and 40b are aligned with the eccentric direction of the pivot shaft portion 22 with respect to the support shaft portion 21. Main cage 39
It is located on the outer part of the. In FIG. 21, 41 is a pocket formed in each cage 39, 40a, 40b, 42a,
42b is a race 31 which constitutes a thrust needle bearing.
Of the outer peripheral edge and the inner peripheral edge, respectively.

A portion of the plurality of needles 33, 33 constituting such a thrust needle bearing, the inner and outer circles of which are defined by the inscribed circle and the circumscribed circle, and the portion between adjacent needles that are adjacent to each other are defined by the needles. It becomes the load receiving part that can support the thrust load. In the case of the structure shown in FIG. 21, the one donut-shaped portion, the two arc-shaped portions, and the portion between these portions serve as the load receiving portion. In the case of the thrust needle bearing used in the experiment, when the load bearing portion and the pitch circle a of the thrust ball bearing 26 are overlapped when viewed in the axial direction of the pivot shaft portion 22, the pitch circle a Approximately 65% of the perimeter was included in the load receiving portion. That is, of the alternate long and short dash line representing the pitch circle a, the portion indicated by the thick line is included in the load receiving portion, while the portion indicated by the thin line is deviated from the load receiving portion.

From this fact, it was confirmed that sufficient durability cannot be obtained only by backing up about 65% of the pitch circle a of the balls 29, 29 constituting the thrust ball bearing 26 against the thrust load. Was done. In view of such circumstances, the present inventor previously invented a toroidal type continuously variable transmission as shown in FIGS. 22 to 25 (Japanese Patent Application No. 6-5997).
issue).

[0026]

Description of Prior Invention First, FIG. 22 shows a first structural example of the aforementioned prior invention. The thrust needle bearing 27a is
It has a main retainer 39A formed in an annular shape and a sub retainer 40A formed in an arc shape. In the case of the toroidal type continuously variable transmission of the previous invention, the diameter of the main retainer 39A is larger than that of the toroidal type continuously variable transmission belonging to the conventional structure shown in FIG. The diameter is larger than the diameter of the main cage 39). And this main cage 39A
Are arranged around the pivot shaft portion 22 that constitutes the displacement shaft 7.

The main cage 39A has a large number of pockets 4
1, 41 are formed in a radial direction centered on the pivot shaft portion 22. And, each of the needles 33, 33 is rotatably held in each of the pockets 41, 41. The spacing (pitch) between the adjacent needles 33, 33 of the plurality of needles 33, 33 is at most 5% or less of the circumferential length of the pitch circle a of the balls 29, 29 constituting the thrust ball bearing 26. Are arranged in.

Therefore, when the needles 33, 33 are arranged at equal intervals, the number of needles 33, 33 must be 20 or more. The needles 33, 33 do not necessarily have to be arranged at equal intervals. However, when arranging them at unequal intervals, 5% of the above perimeter even at the widest interval
The minimum required number of needles 33, 33 is increased so as to be within the range. In general, 50 to 33 needles 33, 33 are arranged at equal intervals so that the interval becomes 2 to 3% of the circumference.

A portion (an annular portion in which the plurality of needles 33, 33 are arranged) whose inner and outer circumferences are defined by the inscribed circle and the circumscribed circle of the plurality of needles 33, 33 is thrust by the needles 33, 33. It becomes the load receiving part that can support the load. In the case of the first structural example shown in FIG. 22, the load bearing portion and the pitch circles a of the plurality of balls 29, 29 constituting the thrust ball bearing 26 are connected to the pivot shaft portion 22.
When stacked in the axial direction (direction of front and back in FIG. 22),
The pitch circle a is included in the load receiving portion over the entire length thereof. That is, in the case of this structural example, the pitch circle a
Is included in the load receiving portion.

The inner surface of the trunnion 6 is in contact with the rolling surfaces of the plurality of needles 33, 33.
A race 31A made of a hard metal plate is attached. This race 3
The outer peripheral edge 42a of 1A is substantially concentric with the pivot shaft portion 22, and the inner peripheral edge 42b is substantially concentric with the support shaft portion 21 that constitutes the displacement shaft 7 together with the pivot shaft portion 22. If the trunnion 6 is made of hard metal, the race 31A can be omitted by smoothing the inner surface. However, in general, it is difficult to increase the surface hardness of the trunnion 6 that requires a large toughness (if the surface hardness that can be used as the raceway surface is secured as it is, the trunnion 6 lacks in toughness). Further, in order to use the inner side surface of the trunnion 6 as it is as a raceway surface, polishing is required to finish the inner side surface with high accuracy (roughness).
This causes an increase in manufacturing cost. Therefore, the race 31A is used.

On the other hand, the sub-retainer 40A is the same as that shown in FIG.
Unlike the structure shown in FIG. 1, it is arranged inside the main cage 39A on an arc centered on the support shaft portion 21. This auxiliary cage 40A is part of the race 31A.
The supporting shaft portion 21 is also provided in a portion facing the outer peripheral edge of
Forming a circular arc-shaped ridge 43. The auxiliary cage 40A is positioned between the protrusion 43 and the outer peripheral surface of the support shaft portion 21. Then, the needle 3 held in the pockets 41, 41 of the sub-retainer 40A
Reference numerals 3 and 33 denote a part of the outer surface of the outer ring 30, which is the support shaft portion 2.
The inner peripheral portion of the eccentric portion is supported.

During operation of the toroidal type continuously variable transmission of the prior invention constructed as described above, the power roller 8 (see FIGS.
The input side, the output side, the disks 2, 4 (see FIG. 15)
17) and the elastic deformation of each member, the outer surface of the outer ring 30 and the inner surface of the trunnion 6 are displaced relative to each other. This relative displacement is performed with a light force as the plurality of needles 33, 33 constituting the thrust needle bearing 27a roll. Further, since the displacement amount of the power roller 8 and the outer ring 30 is small, the pitch circle a does not come off from the load receiving portion due to this displacement.

That is, in the case of the toroidal type continuously variable transmission according to the previous invention, the outer ring 30 covers the entire length of the pitch circle a of the balls 29, 29 regardless of the displacement of the power roller 8 and the outer ring 30. Backed up (thrust load is supported on the outer surface side). Therefore, the thrust load applied to the power roller 8 due to the operation of the toroidal type continuously variable transmission is
Even when repeatedly applied via the balls 29, 29, a large bending stress is less likely to be applied to the outer ring 30. As a result, the outer ring raceway of the outer ring 30 is less likely to be peeled off or damaged such that the outer ring 30 is cracked. Therefore, the durability of the outer ring 30 and the toroidal type continuously variable transmission incorporating the outer ring 30 can be improved.

Next, FIGS. 23 to 25 show a second structural example of the prior invention. In the case of the first structural example described above, mainly,
The thrust needle bearing 27a is configured by combining the auxiliary and two cages 39A and 40A, whereas in the case of this structural example, one cage 44 having the shape as shown in FIG. This constitutes a thrust needle bearing 27b as shown in FIGS.

The holder 44 is formed by forming a plurality of pockets 41, 41 each having an elongated rectangle on a substrate 45 such as a metal plate or a synthetic resin plate. The outer peripheral edge 46 of the retainer 44, when mounted between the outer surface of the outer ring 30 of the thrust ball bearing 26 and the inner surface of the trunnion 6, has
Is almost concentric with the pivot shaft portion 22 that constitutes
Is substantially concentric with the support shaft portion 21 forming the displacement shaft 7.

Further, in the case of this structural example, the cage 4
4 each pocket 41, 41 formed in 4
Support shaft portion 21 constituting the displacement shaft 7 and the longitudinal direction of 1, 41
It is formed in a state in which the radiation direction centered on the point o on the central axis of is matched. Therefore, each pocket 41, 41
The axial directions of all the needles 33, 33 held inside coincide with the direction of radiation centered on the point o.

During operation of the toroidal type continuously variable transmission, the power roller 8 (see FIGS. 15 to 18) swings on the input side and output side, the disks 2 and 4 (see FIGS. 15 to 17), and the elasticity of the constituent members. The outer ring 30 is displaced based on the deformation, and when the outer surface of the outer ring 30 and the inner surface of the trunnion 6 are relatively displaced with this displacement, the outer ring 30 swings around the support shaft portion 22. In the case of this structural example, all of the above needles 3
The axial directions of 3 and 33 are arranged at right angles to the swinging direction of the outer ring 30. In other words, all the needles 33, 33 constituting the thrust needle bearing 27b.
The axial direction of is coincident with the radial direction centered on the center o of the support shaft portion 21. Therefore, unlike the case of the first structural example described above, sliding friction does not occur between the rolling surface of each needle 33, 33 and the mating surface when the outer ring 30 swings. That is, in the case of this structural example, each of the needles 3
The contact state between the rolling surfaces 3 and 33 and the mating surface is close to 100% rolling contact. As a result, relative displacement between the outer surface of the outer ring 30 and the inner surface of the trunnion 6 can be performed more smoothly than in the case of the first structural example.

In the case of the toroidal type continuously variable transmission of the previous invention, it is an essential condition that 70% or more of the pitch circle a of the balls 29, 29 constituting the thrust ball bearing 26 overlap the load receiving portion. is there. If it is 70% or more, excellent durability can be obtained as compared with the conventional structure even if they do not necessarily overlap 100% as in the illustrated first and second structural examples. Of course, if they are overlapped by 100%, the durability is improved as compared with the case of about 70%. Further, among the plurality of needles 33, 33 constituting the thrust needle bearings 27a, 27b, it is necessary that the interval between the adjacent needles 33, 33 be 5% or less of the circumferential length of the pitch circle a. It is a load receiving part that should secure 70% or more. 70% of this
If the above can be secured, the durability can be improved as compared with the conventional structure even if the interval of the remaining portion (the portion of 30% or less of the circumferential length) exceeds the above 5%. However, in order to further improve the durability, the above-mentioned interval is preferably 5% or less of the circumferential length over the entire length.

[0039]

According to the toroidal type continuously variable transmission according to the above-mentioned invention, the thrust ball bearing 26 is provided.
By improving the durability of the outer ring 30 constituting the
Can improve the durability and reliability of the toroidal type continuously variable transmission including the following. To further improve the durability, consider the improvement of the durability of the needles 33, 33 in the following aspects. There is a need.

That is, in the toroidal type continuously variable transmission of the above-mentioned invention, although the durability of the outer ring 30 which constitutes the thrust ball bearing 26 is taken into consideration, the durability of the components of the thrust needle bearing 27 is considered. No particular consideration is given to More specifically, the thrust needle bearing 2
Since a mechanism for limiting the amount of displacement of the cages 39A, 44 constituting 7 is not provided, the needles 33, 33 held in the pockets 41, 41 of the cages 39A, 44 can be detached from the inner surface of the trunnion 6. There is a nature. Thus, when the needles 33, 33 come off the inner surface of the trunnion 6,
When a part of the rolling surface of the needles 33, 33 hits the edge of the thrust raceway surface, an excessive surface pressure acts on a part of this rolling surface, and the fatigue life of the rolling surface is impaired. Further, in a remarkable case, the needles 33, 33 may fall out of the pockets 41, 41.

In the case of the prior invention structure shown in FIGS. 22 and 25, the outer diameter dimension of the race 31A for abutting the rolling surfaces of the needles 33, 33 is set to the width dimension of the trunnion 6 (FIG. 22). , 25 in the left-right direction),
The above-mentioned dropout is prevented from occurring. However, the needle 33,
It is not possible to prevent the 33 from coming off from the inner side surface of the trunnion 6, and it is impossible to prevent an excessive surface pressure from acting on the rolling surfaces of some of the needles 33, 33. That is, the needles 33, 3
Even if the rolling surface of 3 faces the race 31A, if the race 31A is not backed up by the inner surface of the trunnion 6, excessive rolling contact pressure is applied to the rolling surface facing the edge of the trunnion 6. To work.

As described above, even if the outer diameter of the race 31A is made larger than the width of the trunnion 6, the needles 33, 3
The effect of preventing excessive surface pressure from acting on the rolling surface of No. 3 is insufficient. Further, in consideration of reduction in material cost of the race 31A, reduction in weight, and prevention of interference between the outer peripheral edge of the race 31A protruding from both sides in the width direction of the trunnion 6 and other components, the shape of the race 31A is considered. Trunnion 6
It is preferable to match the shape of the inner surface of the. In such a case, not only is it possible to prevent excessive surface pressure from acting on the rolling surfaces of the needles 33, 33, but also to ensure that these needles 33, 33 fall out of the pockets 41, 41. The structure must be preventable. The toroidal type continuously variable transmission of the present invention was invented in view of such circumstances.

[0043]

The toroidal type continuously variable transmission of the present invention is concentric with each other in the state where the inner side surfaces thereof face each other, like the above-described conventional toroidal type continuously variable transmission. In addition, the first and second discs rotatably supported, and the trunnion swinging about a pivot in a twisted position with respect to the central axes of the first and second discs are parallel and eccentric to each other. Having a support shaft portion and a pivot shaft portion,
The trunnion is rotatably supported by the supporting shaft portion, and the pivot shaft portion is rotatably supported around the displacement shaft and the pivot shaft portion protruding from the inner surface of the trunnion. In the state, the power roller sandwiched between the first and second disks, and the power roller is provided so as to be attached to the outer surface of the power roller, while supporting the load in the thrust direction applied to the power roller, A thrust ball bearing that allows the power roller to rotate, and a thrust load applied from the power roller to the outer ring are provided between the outer surface of the outer ring that constitutes the thrust ball bearing and the inner surface of the trunnion. In addition, a thrust needle bearing that allows the pivot shaft portion and the outer ring to swing about the support shaft portion is provided. And, 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 side surface are in contact with each other.

The toroidal type continuously variable transmission of the present invention is
Similarly to the toroidal continuously variable transmission according to the previous invention described above, the following conditions are all satisfied. When the load bearing portion capable of bearing a thrust load by a plurality of needles constituting the thrust needle bearing and the pitch circle of the thrust ball bearing are overlapped in the axial direction of the pivot shaft portion, the pitch circle 70% or more of the circumference is included in the load receiving portion. Among the plurality of needles forming the thrust needle bearing, at least the needle existing in the load receiving portion corresponding to 70% or more of the circumferential length has a distance between adjacent needles of at least the pitch circle of the thrust ball bearing. It is arranged so as to be 5% or less of the circumference. Of course, these conditions must be satisfied regardless of the relative displacement between the trunnion and the outer ring.

In particular, the toroidal type continuously variable transmission according to the first aspect of the present invention satisfies the following conditions. The thrust needle bearing is provided with a retainer that rotatably holds all the needles, and between the retainer and the trunnion, the retainer swings around the support shaft portion. A concavo-convex engaging portion is provided for limiting the dynamic displacement angle. The axial directions of all the needles that make up the thrust needle bearing coincide with the radial direction around the support shaft portion.

Further, in the toroidal type continuously variable transmission according to a second aspect of the present invention, a recess having a predetermined width is formed in the middle portion of the inner side surface of the bent portion that is bent from the end of the trunnion to the side where the power roller is installed. A convex portion having a width dimension smaller than the predetermined width dimension is formed at a portion of the end edge facing the bent portion, the convex portion projecting from the end edge. Then, a concave-convex engaging portion is formed by inserting the convex portion into the concave portion, and a portion of the inner side surface of the trunnion corresponding to the concave portion is also a thrust needle of the inner side surface. A plurality of needles constituting the bearing project toward the power roller side more than a portion where the needles face or abut.

[0047]

The toroidal type continuously variable transmission of the present invention configured as described above transmits the rotational force based on the same action as the above-described conventional toroidal type continuously variable transmission, and further increases the rotational speed ratio. Change. Further, like the toroidal type continuously variable transmission of the previous invention, the outer ring forming the thrust ball bearing is backed up in a wide range (70% or more of the circumference of the pitch circle), so that when a thrust load is applied. However, it becomes difficult to apply a large bending stress to this outer ring. As a result, the outer ring is less likely to be damaged by peeling or cracking, and the durability of the toroidal type continuously variable transmission can be improved.

Particularly, in the case of the toroidal type continuously variable transmission of the present invention, the swinging displacement angle of the cage is limited by the concave-convex engaging portion provided between the trunnion and the cage.
It is possible to prevent the needle that constitutes the thrust needle bearing from coming off the thrust raceway surface, and to prevent the rolling surface of the needle from damaging the thrust raceway surface by contacting the edge of the thrust raceway surface. Further, it is possible to reliably prevent the needle from falling out of the cage pocket. If the condition of is not satisfied, the contact state between the rolling surface of each needle and the mating surface is
It will include sliding contact. Therefore, the friction loss in the thrust needle bearing portion becomes large, the outer ring of the thrust ball bearing cannot be smoothly displaced, and the efficiency of the toroidal continuously variable transmission is reduced. Therefore, by satisfying the above conditions, the contact state between the rolling surface and the mating surface is brought into a substantially 100% rolling contact state, and the friction loss in the thrust needle bearing portion is reduced. As a result, the outer ring of the thrust ball bearing is smoothly displaced, and the efficiency of the toroidal type continuously variable transmission is improved.

Further, in the case of the toroidal type continuously variable transmission according to the second aspect, a portion of the inner surface of the trunnion corresponding to the recess and a plurality of thrust needles constituting the inner surface of the trunnion. It is possible to process the part where the needle faces or abuts with a different tool. Therefore, it is possible to efficiently process the portion where a plurality of needles having a larger area than the portion facing the recessed portion face or abut. The details of this reason will be described later.

[0050]

1 to 5 show a first embodiment of the present invention corresponding to claim 1. The feature of the present invention is that the needles 33, 33 constituting the thrust needle bearing 27c are retained on the inner side surface of the trunnion 6 so as to prevent the needles 33, 33 from protruding from the attached race 31B without protruding from the inner side surface. The concave-convex engaging portion is provided between the container 48 and the trunnion 6. Since the structure and operation of many other parts are the same as in the case of the above-mentioned prior invention, the description of the equivalent parts will be omitted or simplified, and the characteristic part of the present invention will be mainly described below.

The retainer 48 is formed by forming a plurality of pockets 41, 41 each having an oblong shape on a substrate 49 formed in a substantially oval shape with a metal plate, a synthetic resin plate or the like. Further, in a part of the substrate 49, which is slightly deviated from the center to one side in the length direction (lower side in the vertical direction in FIGS. 1 and 2),
A circular hole 50 and a notch 51 projecting radially outward from a part of the circular hole 50 are formed. A protrusion 52 formed on the inner surface of the trunnion 6 is rotatably fitted into the circular hole 50 without rattling. One end of a circular hole 23 formed in the trunnion 6 for inserting the support shaft portion 21 of the displacement shaft 7 (see FIGS. 17 to 18 described above or FIG. 10 described later) is opened inside the protrusion 52. There is. With the circular hole 50 fitted onto the protrusion 52, the retainer 48 is
The length directions of the pockets 41, 41 formed on the substrate 49 of (1) coincide with the radial direction centered on the circular hole 50.
Therefore, the axial direction of all the needles 33, 33 forming the thrust needle bearing 27c coincides with the radial direction around the support shaft portion 21 inserted into the circular hole 23.

In the illustrated embodiment, the plurality of pockets 41, 41 are arranged in a polished shape, and are separated from the pivot shaft portion 21 (toward the upper side in FIGS. 1 and 2) in the width direction on both sides (FIG. Pockets 4 located on the left and right sides of 1-2)
The distance between 1, 41 is narrowed. this is,
Despite the swinging of the cage 48 centered around the ridge 52,
The needles 33 held in the pockets 41, 41,
This is to reliably prevent the rolling surface of 33 from protruding from the race 31B. Further, the left and right edges of the base plate 49 are formed in a mountain shape so that the base plate 49 does not largely project from the left and right sides of the trunnion 6 regardless of the swing.

Furthermore, in the case of the toroidal type continuously variable transmission of the present invention, the convex portion 54 is formed at one end (upper end in FIGS. 1 and 2) of the substrate 49 in the length direction. On the other hand, on both ends of the trunnion 6 in the length direction (upper and lower ends in FIGS. 1 and 2, front and back ends in FIGS. 3 and 5, left and right ends in FIG. 4), the power roller installation side (front side in FIGS. 1 and 2, FIG. Of the bent portions 55a and 55b formed in a bent state (toward the lower side of 5), a concave portion 56 is formed in the middle portion of the inner side surface of the bent portion 55a facing the convex portion 54. The width dimension W ₅₆ of the concave portion ₅₆ is slightly larger than the width dimension W ₅₄ of the convex portion 54 (W ₅₆ > W ₅₄ ). Then, the circular hole 50 is replaced with the protrusion 52.
The convex portion 54 is loosely fitted in the concave portion 56 in a state where the convex portion 54 is externally fitted. Therefore, the cage 48 is within the range where the convex portion 54 can be displaced inside the concave portion 56 (“W ₅₆ −
(Within a stroke range of W ₅₄ )), the support shaft portion 21 is swingable. 1 and 2 showing the present embodiment, FIG. 1 shows a state in which the cage 48 is in the neutral position, and FIG. 2 shows a state in which the cage 48 is most pivotally displaced. In the case of the present invention, Not only in the neutral state shown in FIG. 1 but also in the maximum displacement state shown in FIG. 2, a part of the needles 33, 33 does not come off from the race 31B. Incidentally, reference numeral 57 in FIGS. 1 and 2 denotes an oil hole for circulating the lubricating oil. The oil hole 57 is aligned with the notch 51 and feeds the lubricating oil to a necessary place. Therefore, regardless of the swing displacement of the cage 48, the notch 51
Is sized so that a part of it matches the oil hole 57.

In the case of the toroidal type continuously variable transmission of the present invention configured as described above, the recess 56 formed in the intermediate portion of the inner side surface of the bent portion 55a of the trunnion 6 and one end in the longitudinal direction of the retainer 48. The swinging displacement angle of the cage 48 is limited by the concave-convex engaging portion formed by the convex portion 54 formed in the middle portion of the edge. Therefore, it is possible to prevent the needles 33, 33 forming the thrust needle bearing 27c from coming off from the race 31B forming the thrust raceway surface. As a result, it is possible to prevent the rolling surface of each of the needles 33, 33 from abutting the edge of the race 31B and damaging the rolling surface. In addition, the needles 33, 33 are attached to the retainer 48.
It can be surely prevented from falling out of the pockets 41, 41.

Next, FIGS. 6 to 7 show a second embodiment of the present invention corresponding to claim 1. In the case of this embodiment,
Inner side surface intermediate portion 2 of the bent portion 55a of the trunnion 6
Recesses 56a and 56a formed at the positions and the retainer 48
Convex portion 5 formed at two positions in the middle of one end edge in the length direction of a
The swing displacement angle of the retainer 48a is limited by the two sets of concave-convex engaging portions composed of 4a and 54a. Other configurations and operations are similar to those of the above-described first embodiment. The small circular hole 58 formed in the central portion of the one end of the retainer 48a in the lengthwise direction is for positioning the retainer 48a during the assembling work and is not related to the gist of the present invention.

Next, FIGS. 8 to 9 show a third embodiment of the present invention corresponding to claim 1. In the case of this embodiment,
A notch 59 is formed at one end edge of the retainer 48b in the lengthwise direction (upper edge of FIGS. 8 to 9), and a pin 60 is projectingly provided at the center of one end in the lengthwise direction of the inner surface of the trunnion 6. Then, by engaging the pin 60 also corresponding to the convex portion with the inside of the notch 59 corresponding to the concave portion of the claims, the concave-convex engagement for limiting the swing displacement angle of the retainer 48b. Forming a part. Other configurations and operations are similar to those of the above-described first embodiment and the above-described second embodiment.

Next, FIGS. 10 to 12 show a fourth embodiment of the present invention, which corresponds to the second aspect. In the case of this embodiment, a step 61 is provided on the inner side surface of the trunnion 6.
That is, of the inner side surface, the portion corresponding to the concave portion 56 formed on the inner side surface of the bent portion 55a corresponds to the race 31B on which the plurality of needles 33, 33 constituting the thrust needle bearing 27c also abut on the inner side surface. Is protruded toward the side where the power roller 8 is provided (the right side in FIG. 10, the front side in FIGS. 11 to 12) from the portion where the power roller is attached. In the illustrated embodiment, the height h of the step 61 is set to the race 31.
It is the same as or slightly smaller than the thickness dimension T of B (h ≦ T). In the case of the present embodiment, by providing such a step 61 on the inner side surface of the trunnion 6, the trunnion 6 can be efficiently processed.

For this reason, FIG. 12 and FIGS.
The description will be made with reference to. The distance between the center lines of the pivots 5, 5 provided at both ends of the trunnion 6 and the inner surface of the trunnion 6 must be accurately finished. The reason for this is
This is because the contact position between the peripheral surface 8a of the power roller 8 and the inner side surfaces 2a, 4a (FIGS. 15 to 17) of both the input side and output side disks 2, 4 is made proper. On the other hand, the trunnion 6 which is required to have high strength is manufactured by forging a metal material (mainly steel). However, it is not possible to finish the above distance to the required accuracy only by forging, and the race 31B
It is also difficult to secure sufficient flatness of the inner side surface with which the abutment is made to abut. Therefore, the inner surface of the trunnion 6 needs to be cut after the forging. For example, as shown in FIG. 13 (A), such a cutting process is performed after a large part of the inner surface of the trunnion 6 is machined with a tool 65 having a large diameter D, and then the bent part 55a which cannot be machined by the tool 65. The corner portion of is processed with a tool 62 having a small diameter d as shown in FIGS. Incidentally, FIG. 13 (A) shows the small tool 6
2 shows the initial stage of processing, and FIG. 2B shows the final stage of processing. By using such a processing method, the flatness of the inner surface can be improved as compared with the case where only the casting process is performed. However, in order to secure the above dimensional accuracy and flatness to a high degree, it is not preferable to replace the tool during cutting according to the processing portion (position in the surface direction).

The efficiency of the cutting work becomes better as the diameter of the rotary tool used increases, but the maximum value of the diameter of the rotary tool that can be used is restricted by the shape of the surface to be cut. For example, as shown by the slanted lattice in FIG. 14, when the portion including the concave portion 56 is machined at once, the diameter of the concave portion 56 can be machined so that the corners of the concave portion 56 can be machined. With the tool 62 having a small d, it is necessary to process the entire portion indicated by the slant grid. Therefore, the time required for processing becomes long and the manufacturing cost of the trunnion 6 increases. FIG.
If the inner surface of the trunnion 6 is machined by the method as shown in (1), the surface accuracy can be obtained without any practical problems, but there is a possibility that a minute step may be formed in part.

On the other hand, in the case of this embodiment, since the step 61 is originally present between the portion 63 corresponding to the recess 56 and the portion 64 where the race 31B is provided, both these portions 63 are provided. , 64 need not be machined with the same tool. Therefore, as shown in FIG. 12, with the tool 62 having a small diameter d, only the portion 63 corresponding to the recess 56 is processed, and the portion 64 to which the race 31B is attached is formed by the tool 65 having a large diameter D. It becomes possible to perform processing. Therefore, a portion 64 having a larger area than the portion facing the concave portion 56 and provided with the race 31B is provided.
Can be processed efficiently. As a result, the trunnion 6 and the trunnion 6 are made more efficient by machining the trunnion 6 more efficiently than when machining the entire surface with a tool having a small diameter.
It is possible to reduce the manufacturing cost of the toroidal type continuously variable transmission incorporating the. Other configurations and operations are similar to those of the first embodiment described above. 11-14, the notch 51 formed in the cage 48, the small circular hole 58 for positioning, and the oil hole 57 formed in the trunnion 6 are omitted.

[0061]

Since the toroidal type continuously variable transmission of the present invention is constructed and operates as described above, it is possible to improve the durability of the outer ring which constitutes the thrust ball bearing, as in the case of the previous invention. it can. Further, since it is possible to prevent the needle constituting the thrust needle bearing from coming off the thrust raceway surface, it is possible to prevent the rolling surface of the needle from damaging the thrust raceway surface by contacting the edge of the thrust raceway surface. Further, it is possible to reliably prevent the needle from falling out of the cage pocket. As a result, the durability and reliability of the toroidal type continuously variable transmission including the outer ring and the needle can be improved.

[Brief description of drawings]

FIG. 1 is an inner side view of a trunnion assembled with a thrust needle bearing, showing a first embodiment of the present invention in a neutral state.

FIG. 2 is a view similar to FIG. 1, also showing the maximum displacement state.

FIG. 3 is a view of the trunnion viewed from above in FIG.

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

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

FIG. 6 is a view similar to FIG. 1, showing a second embodiment of the present invention.

FIG. 7 is a view similar to FIG.

FIG. 8 is a view similar to FIG. 1, showing a third embodiment of the present invention.

FIG. 9 is a view similar to FIG.

FIG. 10 is a sectional view showing a fourth embodiment of the present invention in a state in which a power roller is attached to a trunnion.

11 is a view seen from the right side of FIG. 10 except for a power roller, a thrust ball bearing, and a displacement shaft.

FIG. 12 is a diagram seen from the right side of FIG. 10 with the thrust needle bearing removed.

FIG. 13 is a view of the trunnion adopted in the first embodiment seen from the same direction as FIG. 12 in order to explain a first example of troubles in trunnion processing that occurs when the structure of the fourth embodiment is not adopted.

FIG. 14 is a view similar to FIG. 13 for explaining the second example.

FIG. 15 is a side view showing a basic configuration of a conventionally known toroidal type continuously variable transmission in a state of maximum deceleration.

FIG. 16 is a side view showing the same state at the time of maximum acceleration.

FIG. 17 is a sectional view showing an example of a conventional specific structure.

18 is a cross-sectional view taken along the line CC of FIG.

FIG. 19 is a view of the thrust needle bearing incorporated in the conventional structure as viewed from the same direction as FIG. 1.

FIG. 20 is an enlarged DD sectional view of FIG. 19;

FIG. 21 is a view similar to FIG. 1, showing a thrust needle bearing manufactured according to a conventional structure for performing a durability test.

FIG. 22 is a perspective view of a trunnion inner surface portion in which a thrust ball bearing and a thrust needle bearing are assembled, showing a first structural example of the prior invention.

FIG. 23 shows a cage used in the second structural example of the prior invention,
The figure seen from the same direction as FIG.

24 is a view showing a state in which the cage is combined with a race, a pivot, and a thrust ball bearing, as viewed from the same direction as FIG. 22.

FIG. 25 is a view similar to FIG. 22, showing a second structural example of the prior invention.

[Explanation of symbols]

 1 Input Shaft 2 Input Side Disk 2a Inner Side Surface 3 Output Shaft 4 Output Side Disk 4a Inner Side Surface 5 Axis 6 Trunnion 7 Displacement Axis 8 Power Roller 8a Circumferential Surface 9 Pressing Device 10 Cam Plate 11 Cage 12 Roller 13, 14 Cam Surface 15 Input shaft 16 Needle bearing 17 Collar part 18 Output gear 19 Key 20 Support plate 21 Support shaft part 22 Pivot shaft part 23 Circular hole 24, 25 Needle bearing 26 Thrust ball bearing 27, 27a, 27b, 27c Thrust needle bearing 28 Cage 29 balls 30 outer ring 31, 31A, 31B race 32 retainer 33 needles 34a, 34b annular portion 35a, 35b protrusion 36 drive rod 37 drive piston 38 drive cylinder 39, 39A main retainer 40a, 40b, 40A auxiliary retainer 41 Pocket 42a Outer peripheral edge 42b Inner peripheral edge 43 Projection 44 retainer 45 substrate 46 outer peripheral edge 47 inner peripheral edge 48, 48a, 48b retainer 49 substrate 50 circular hole 51 notch 52 ridge 54, 54a convex portion 55a, 55b bent portion 56, 56a concave portion 57 oil hole 58 small circular hole 59 Notch 60 Pin 61 Step 62 Tool 63, 64 Part 65 Tool

Claims (2)

[Claims] 1. In a state in which the inner surfaces of each other are opposed to each other,
First and second discs that are concentrically and rotatably supported, and a trunnion that swings about a pivot that is in a twisted position with respect to the central axes of these first and second discs and is parallel to each other. A displacing shaft having an eccentric support shaft portion and a pivot shaft portion, the support shaft portion being rotatably supported by the trunnion, and the pivot shaft portion protruding from the inner surface of the trunnion. And a power roller sandwiched between the first and second disks in a state of being rotatably supported around the pivot shaft portion, and provided on the outer side surface of the power roller. Between the outer surface of the outer ring forming the thrust ball bearing and the inner surface of the trunnion, the thrust ball bearing allowing the rotation of the power roller while supporting the load in the thrust direction applied to the power roller. Provided A thrust needle bearing that allows the pivot shaft portion and the outer ring to swing around the support shaft portion while supporting the thrust load applied from the power roller to the outer ring; The inner surface of the second disk is a concave surface having an arcuate 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 of~
A toroidal type continuously variable transmission that meets all of the above conditions. When the load bearing portion capable of bearing a thrust load by a plurality of needles constituting the thrust needle bearing and the pitch circle of the thrust ball bearing are overlapped in the axial direction of the pivot shaft portion, the pitch circle 70% or more of the circumference is included in the load receiving portion. Among the plurality of needles forming the thrust needle bearing, at least the needle existing in the load receiving portion corresponding to 70% or more of the circumferential length has a distance between adjacent needles of at least the pitch circle of the thrust ball bearing. It is arranged so as to be 5% or less of the circumference. The thrust needle bearing is provided with a retainer that rotatably holds all the needles, and between the retainer and the trunnion, the retainer swings around the support shaft portion. A concavo-convex engaging portion is provided for limiting the dynamic displacement angle. The axial directions of all the needles forming the thrust needle bearing are aligned with the radial direction around the support shaft portion. 2. A recess having a predetermined width dimension is formed in an intermediate portion of an inner side surface of the bent portion bent from the end portion of the trunnion to the side where the power roller is installed, and this end portion is provided at a portion of the end edge of the retainer facing the bent portion. Projections protruding from the edge, each having a width dimension smaller than the predetermined width dimension, are formed, respectively, the concave-convex engagement portion is formed by entering this convex portion inside the concave portion, A portion of the inner side surface of the trunnion corresponding to the concave portion projects toward the power roller more than a portion of the inner side surface on which a plurality of needles forming a thrust needle bearing face or abut. The toroidal type continuously variable transmission described in 1.