JPH08178007A - Toroidal type continuously variable transmission - Google Patents

Abstract

PURPOSE: To prevent the interference between trunnions and inside faces of both disks on the input side and output side and apply sufficient rigidity to the trunnions. CONSTITUTION: The size in the diameter direction of an inner half section 36 entering between inside faces 2a, 4a is set small. The size in the diameter direction of an outer half section 37 not entering between both faces 2a, 4a is set large to secure rigidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The toroidal type continuously variable transmission according to the present invention is used as, for example, an automobile transmission.

[0002]

2. Description of the Related Art As a transmission for an automobile, use of a toroidal type continuously variable transmission as schematically shown in FIGS. The toroidal type continuously variable transmission supports an input side disk 2 concentrically with an input shaft 1 and an output side disk 4 at an end of an output shaft 3 as disclosed in Japanese Utility Model Laid-Open No. 62-71465. Is fixed. An inner surface of a casing accommodating the toroidal type continuously variable transmission, or a support bracket provided in the casing swings around a pivot shaft 5 in a twisted position with respect to the input shaft 1 and the output shaft 3. A trunnion 6, 6 is provided.

The trunnions 6 and 6 are shown in FIGS.
As shown in FIG. 3, the shafts 5 and 5 are provided on the outer surfaces of both ends by being formed of a metal material having sufficient rigidity. In addition, a circular hole 7 formed in the center of each trunnion 6, 6.
The base ends of the displacement shafts 8 (FIGS. 9 to 10) are supported by the pivot shafts 5 and 5, and each trunnion 6 is swung to adjust the inclination angle of each displacement shaft 8. .
Power rollers 9, 9 are rotatably supported around displacement shafts 8, 8 supported by the trunnions 6, 6, respectively. The power rollers 9, 9 are sandwiched between the input side and output side disks 2, 4. Inner side surfaces 2 of the input side and output side disks 2 and 4 facing each other
Each of a and 4a has an arcuate concave surface whose cross section is centered on the pivot 5. The peripheral surfaces 9a, 9a of the power rollers 9, 9 formed in the spherical convex surface are in contact with the inner side surfaces 2a, 4a.

A loading cam type pressurizing device 10 is provided between the input shaft 1 and the input side disc 2, and the input side disc 2 is elastically directed toward the output side disc 4 by the pressurizing device 10. Is pressed against. This pressurizing device 1
0 is a cam plate 11 that rotates together with the input shaft 1, and a retainer 1
A plurality of (for example, four) rollers 1 held by 2
It is composed of 3 and 13. On one side surface (right side surface in FIGS. 9 to 10) of the cam plate 11, there is formed a cam surface 14 which is an uneven surface extending in the circumferential direction, and the input side disk 2 is provided.
The same cam surface 1 on the outer surface (left side surface in FIGS. 9 to 10) of
5 is formed. And the plurality of rollers 13,
13 is rotatably provided about the 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 11 rotates with the rotation of the input shaft 1, the cam surface 14 causes the plurality of rollers 13, 1 to rotate.
3 is pressed against the cam surface 15 on the outer surface of the input side disk 2. As a result, the input side disk 2 is pressed against the plurality of power rollers 9 and 9 and at the same time, the input side disk 2 is pressed against the pair of cam surfaces 14 and 15 and the plurality of rollers 13 and 13. 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 9, 9, and the output shaft 3 fixed to the output side disk 4 rotates.

When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, as shown in FIG. As a result, the trunnions 6, 6 are swung so that the peripheral surfaces 9a, 9a of the power rollers 9, 9 are located near 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 8 and 8 are inclined so that they come into contact with each other. On the contrary, in order to increase the speed, the trunnions 6 and 6 are swung as shown in FIG. 10, and the peripheral surfaces 9a and 9a of the power rollers 9 and 9 are fitted to the inner surface 2a of the input side disk 2. Around the outer periphery of the disk and the inner surface 4a of the output side disk 4
The displacement shafts 8, 8 are tilted so that they are brought into contact with the portions closer to the center of the displacement axes. By setting the inclination angles of the displacement shafts 8, 8 in the middle between FIG. 9 and FIG. 10, it is possible to obtain an intermediate gear ratio between the input shaft 1 and the output shaft 3.

FIG. 14 shows each of the trunnions 6 when shifting.
As a mechanism for inclining the pivots 5 and 5, the one described in US Pat. No. 4,928,542 is shown. The pivot shafts 5 and 5 are supported by the needle bearings 16 and 16 relative to the housing 17 so as to be freely rotatable and slightly displaced in the axial direction. At the time of speed change, pressure oil is sent into the hydraulic cylinder 18 supported by the housing 17 to displace the trunnion 6 in the axial direction. Based on this displacement, the peripheral surface 9a of the power roller 9 and the input side,
Inner side surfaces 2a and 4a of both output side disks 2 and 4 (see FIGS.
0) changes the contact positional relationship, and the trunnion 6 swings about the pivots 5 and 5 in any direction.

As is apparent from FIG. 14, the actual displacement shaft 8 is an eccentric shaft in which the base half portion and the front half portion are eccentric to each other, and the base half portion is pivotally supported on the trunnion 6, A power roller 9 is pivotally supported around the half part. Further, a cylindrical surface portion 19 is formed on the maximum diameter portion of the outer peripheral surface of the power roller 9. Furthermore, the outer peripheral edge of the outer ring 20 for pivotally supporting the power roller 9 with respect to the displacement shaft 8 and the outer peripheral edge of the cage 22 holding the balls 21, 21 are the peripheral surface 9a of the power roller 9. Are located inward of the spherical surface obtained by extending the disk so that these outer peripheral edges do not interfere with the inner side surfaces 2a, 4a of both the input side and output side disks 2, 4.

In order to put the toroidal type continuously variable transmission configured and functioning as described above into practical use, while suppressing an increase in weight,
It is desired to improve the performance. On the other hand, the trunnions 6, 6 for swingably supporting the power rollers 9, 9 are heavy in order to secure sufficient rigidity. For this reason, the structure of the trunnions 6, 6 is important for reducing the weight and improving the performance of the toroidal type continuously variable transmission. That is,
When the toroidal type continuously variable transmission is in operation, a large thrust load is applied from one of the power rollers 9, 9 to one surface of each of the trunnions 6, 6 (the surface on which the power rollers 9, 9 are installed). If the rigidity of each of the power rollers 9 and 9 is insufficient and the power rollers 9 and 9 are elastically deformed in a direction in which the one surface side becomes a concave surface, the thrust ball bearing formed by the outer ring 20 and the balls 21 and 21 is biased. A load is applied and the durability of this thrust ball bearing is reduced. Therefore, it is necessary to sufficiently secure the rigidity of each of the trunnions 6, 6, but simply increasing the size of the trunnions 6 and 6 in order to secure the rigidity,
The weight increases unnecessarily, impairing the practicality of the toroidal type continuously variable transmission.

[0010] In consideration of such a situation, an actual Kaihei 6-1460
Japanese Patent Publication No. 3 proposes a trunnion 27 having a shape as shown in FIGS. The trunnion 27 is made of a material having sufficient rigidity such as steel and has a base portion 28.
And a pair of pivots 5 protruding from both end surfaces of the base 28,
5 and 5. The base portion 28 is formed by cutting off a part of a cylindrical material having the first central axis a.
That is, the concave portion 24 is provided by scraping off the one-sided intermediate portion of the material, and the circular hole 29 is bored in the intermediate portion of the concave portion 24. The circular hole 29 supports the base end of the displacement shaft for supporting the power roller. Also, at both ends of the base 28,
The portions apart from the recess 24 are plate portions 25, 25 that are bent with respect to the main body portion 26 having the circular hole 29. Further, the other surface of the material is also milled to form a flat surface 30 parallel to the recess 24. On the outer side surfaces of the pair of plate portions 25, 25, pivots 5 and 5 are respectively provided so as to project. Each of the pivots 5 and 5 formed integrally with the base 28 is parallel to the first central axis a and protrudes from the displacement axis 8 with respect to the first central axis a (see FIGS. 15 to 17). It is formed in a columnar shape having a second central axis b, which is eccentric in the downward direction). In the case of the trunnion 27 configured as described above, the weight of the trunnion 27 can be reduced while ensuring the rigidity.

[0011]

In the case of the trunnion 27 as shown in FIGS. 15 to 17 constructed as described above, in comparison with the conventional trunnion 6 as shown in FIGS. The same rigidity results in a lighter weight. However, the base 28 and the inner side surfaces 2 of both the input side and output side disks 2 and 4
Since the shape is not enough to prevent interference with a and 4a,
It may be difficult to secure the rigidity when the weight is further reduced.

That is, during operation of the toroidal type continuously variable transmission,
In order to increase the gear ratio between the input side disc 2 and the output side disc 4, it is necessary to incline the trunnion 27 largely about the pivots 5 and 5. Further, even when the trunnion 27 is greatly inclined in this way, the side edge of the base portion 28 that constitutes the trunnion 27 and each of the inner side surfaces 2 described above.
It is necessary to avoid interference with a and 4a. On the other hand, the trunnion 27 described in the above publication does not have a shape that takes into consideration preventing such interference. Therefore, in order to prevent the interference even when the inclination angle of the trunnion 27 about the pivots 5 and 5 becomes large,
The width of the base 28 should be reduced. However, the reduction in the width dimension of the base portion 28 leads to the reduction in the rigidity of the base portion 28, so that it is not possible to achieve both weight reduction and ensuring the rigidity. The toroidal type continuously variable transmission of the present invention was invented in view of such circumstances.

[0013]

SUMMARY OF THE INVENTION A toroidal type continuously variable transmission according to the present invention comprises an input side disc and an output side disc which is arranged concentrically with the input side disc and is rotatably supported with respect to the input side disc. And a trunnion that swings about a pair of pivots that are twisted with respect to the central axes of both the input and output disks, a displacement shaft supported by the trunnion, and a rotatably supported by the displacement shaft. And a power roller sandwiched between the input side and output side disks. The inner side surfaces of the input side and output side discs, which face each other, are concave surfaces each having an arcuate cross section, and 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. I am letting you.

Particularly, in the toroidal type continuously variable transmission according to the present invention, a part of the trunnion is moved between the inner side surfaces of the input side disk and the output side disk due to the swing around the pivot axis. The outer surface of the portion that enters into the inner side of the shaft is located diametrically inward of the cylindrical surface that is in contact with each of the inner side surfaces with the pivot axis as the center. On the other hand, the outer surface of the portion that does not enter between the inner side surfaces of the input side and output side disks regardless of the swinging around the pivot in the remaining part of the trunnion is
It exists diametrically outside the cylindrical surface.

[0015]

With the toroidal type continuously variable transmission of the present invention configured as described above, the action itself at the time of freely changing the speed ratio between the input shaft and the output shaft is the same as that of the conventional toroidal type continuously variable transmission described above. This is similar to the case of the transmission. Particularly, in the case of the toroidal continuously variable transmission of the present invention, the rigidity of the trunnion can be maximized in a limited installation space. Further, even when the trunnion is swung about the pivot, the side edge of the trunnion does not interfere with the inner side surfaces of both the input side and output side disks. Therefore, it is possible to obtain a toroidal type continuously variable transmission that is lightweight and has a large gear ratio.

[0016]

1 to 7 show an embodiment of the present invention.
The toroidal type continuously variable transmission of the present invention is characterized by the shape of the trunnion, and the other parts are the same as the conventional structure described above. Therefore, the following description will be focused on the trunnion. The trunnion 31 made of a material having sufficient rigidity such as steel has a base portion 32 at the middle portion in the longitudinal direction (left-right direction in FIGS. 2 and 4). Further, bent portions 33, 33 are formed at both ends in the length direction of the base portion 32, and are bent at right angles from the base portion 32 in the same direction. The base 3
A circular hole 34 is formed in a portion slightly closer to one end (the left end in FIGS. 2 and 4) in the length direction from the central portion of 2. This circular hole 34
14, the base half of the displacement shaft 8 as shown in FIG. 14 is pivotally supported, and the power roller 9 as also shown in FIG. 14 is pivotally supported at the front half of the displacement shaft 8. Power roller 9 in this state
The center of rotation of is located substantially in the center of the base 32.
In addition, the inner side surfaces of the bent portions 33, 33 facing each other are arcuate surface-shaped concave surfaces whose central portions in the width direction (vertical direction in FIG. 4) are recessed. As a result, interference between the bent portions 33, 33 and the power roller 9 is prevented, and bending rigidity of a continuous portion between the bent portions 33, 33 and the base portion 32 is secured.

Concentric pivots 5 and 5 are formed on the outer side surfaces of the bent portions 33 and 33, respectively. In order to reduce the weight of the trunnion 31 to the maximum, these pivots 5, 5
Through holes 35a and 35b are formed in the central portion of the shafts 5 and 5 within a range in which the rigidity of the shafts 5 and 5 can be secured.
5 is formed in a cylindrical shape.

Further, the base portion 32 constituting the trunnion 31 has a sectional shape as shown in FIG. That is, the surface side half (the lower half of FIG. 3) from which the displacement shaft 8 projects is the surface (the lower surface of FIG. 3) from which the displacement shaft 8 projects from the center in the thickness direction (vertical direction of FIG. 3). The width of the inner half 36 is gradually increased toward the inner half 36, and the opposite half (upper half of FIG. 3) is the outer half 37 continuous from the inner half 36. The outer half portion 37 has a large width dimension but a large dimension in the thickness direction.

When such a trunnion 31 is assembled to a toroidal type continuously variable transmission and the input shafts 2 and 4 are largely tilted about the respective pivot shafts 5 and 5 in order to increase the speed ratio between the input disc 2 and the output disc 4. Both widthwise end portions of the inner half portion 36 enter the portion 38 between the inner side surfaces 2a, 4a of both the input side and output side disks 2, 4 shown by the oblique grid in FIG. On the other hand, the S range in FIG. 1 including the outer half portion 37 does not enter the portion 38 during this period. To this end, in the illustrated embodiment, the outer surface of the inner half 36 is provided with the pivots 5, 5,
Is located on the inner side in the diametrical direction with respect to the cylindrical surface in contact with the inner side surfaces 2a, 4a. On the other hand, the outer surface of the outer half portion 37, which is the remaining portion of the trunnion 31, is present on the outer side in the diametrical direction with respect to the inner surfaces 2a, 4a in contact with the inner surfaces 2a, 4a about the pivots 5, 5.

In the case of the toroidal type continuously variable transmission of the present invention constructed as described above, the rigidity of the trunnion 31 provided in the limited installation space can be maximized. That is, the outer half 3 which does not enter the portion 38 between the side surfaces 2a, 4a.
7 can secure a sufficient thickness, so the trunnion 3
The rigidity of 1 can be sufficiently secured. Therefore, the elastic deformation of the trunnion 31 can be suppressed to a very small level, and an unbalanced load can be prevented from being applied to the thrust bearing provided between the power roller 9 and the trunnion 31. Therefore, the durability of this thrust bearing can be sufficiently ensured.

On the other hand, since the inner half portion 36 which enters the portion 38 between the inner side surfaces 2a, 4a is provided on the inner side in the diametrical direction with respect to the cylindrical surface, it is shown in FIGS. As shown, no matter which direction the trunnion 31 is swung about the pivots 5 and 5, both side edges of the trunnion 31 in the width direction and the inner side surfaces 2a and 4a of the input side and output side disks 2 and 4 are formed. And do not interfere. Therefore, it is possible to obtain a toroidal type continuously variable transmission that is lightweight and has a large gear ratio.

In order to further reduce the size and weight of the toroidal type continuously variable transmission, in order to maximize the rigidity of the trunnion 31 installed in a limited space, the number shown in FIG. As in the second embodiment, the outer surface of the outer half portion 37 of the trunnion 31 is positioned on the diametrically inner side of the cylindrical surface indicated by the chain line α in the figure. The cylindrical surface indicated by the chain line α is in contact with the base end portion of the displacement shaft 8 projecting from the outer half portion 37 with the center axis of the pair of pivot shafts 5 as the center. If the shape of the outer half portion 37 is regulated in this way and a casing having a predetermined clearance with respect to the cylindrical surface indicated by the chain line α is made, the trunnion 31 having the highest rigidity in the range that can be accommodated in this casing. Can be obtained.

Further, in order to surely prevent the inner surface 2a of the input side disk 2 and the trunnion 31 from interfering with each other even during an abnormal operation, as in the third embodiment shown in FIG. A portion of the output side disks 2 and 4 which enters the portion 38 between the inner side surfaces 2a and 4a is positioned inside the cylindrical surface indicated by a chain line β in the diametrical direction. The cylindrical surface indicated by the chain line β has a radius r represented by the following formula (1) with the central axis of the pair of pivots 5 as its center.

R = R-L-C --- (1) In this equation (1), R is both the input side and output side disks 2,
The radius of curvature L of the inner side surfaces 2a, 4a of 4 is the height C of the cam surface 15 formed on the back surface of the input side disk 2 so as to constitute the loading cam type pressing device 10. 2a's bus shape is 1 /
When the number of arcs exceeds 4 arcs, this is the amount of overhang of the protrusion existing on the outer peripheral edge of the input side disk 2.

If the inner half portion 36 is disposed inside the cylindrical surface having the radius r obtained by the equation (1) with the central axis of the pair of pivots 5 as the center, the input can be made even during abnormal operation. Interference between the inner surface of the side disc 2 and the trunnion can be reliably prevented.

The reason for this will be described. Generally, in a toroidal type continuously variable transmission, an output side disk 4 is rotatably supported (displaceable in the axial direction), and an input side disk 2 is rotatably and slightly displaceable in the axial direction.
Then, during operation, the input side disk 2 is strongly pressed toward the output side disk 4 by the action of the pressing device 10. Due to this pressing, the input side disc 2 is slightly moved in the axial direction toward the output side disc 4. In this state, the distance between the inner side surfaces 2a, 4a of the two disks 2, 4 is narrowed, and the inner side surfaces 2a, 4a and the inner half portion 36 are closed.
Interference with the outer surface of the.

Normally, the height L of the cam surface 15 is regulated so that the rollers 13, 13 constituting the pressing device 10 do not completely go over the ridge of the cam surface 15.
If an unpredictably large excessive torque is applied to the cam plate 11 for some reason, the roller 13 may completely go over the ridge of the cam surface 15. In such a case, the end edge of the projecting portion existing in the outer peripheral edge portion of the input side disk 2 approaches the cylindrical surface indicated by the chain line β,
It approaches the outer half 37 of the trunnion 31. This is the state where the input side disk 2 and the trunnion 31 are closest to each other. Therefore, if the outer surface exists inside the cylindrical surface represented by the chain line β in FIG. 8, it is possible to eliminate the possibility of the inner surfaces 2a and 4a interfering with the outer surface of the inner half portion 36. still,
As for the overhang amount C, since the input side disk 2 has a circular ring shape, the trunnion 31 is long in the front and back directions in FIG.
It is necessary to consider in order to prevent interference in the three-dimensional direction. Of course, if there is no protrusion (when C = 0), it is not necessary to subtract the amount of overhang.

[0028]

Since the toroidal type continuously variable transmission of the present invention is constructed and operates as described above, the rigidity of the trunnion installed in a limited space can be maximized while ensuring a sufficient gear ratio. I can do things. As a result, the toroidal type continuously variable transmission can be reduced in weight and improved in performance.

[Brief description of drawings]

FIG. 1 is an end view of a trunnion showing a first embodiment of the present invention.

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

3 is a sectional view taken along line BB of FIG.

FIG. 4 is a view seen from below in FIG.

FIG. 5 is a half sectional view of an input side disc and an output side disc.

FIG. 6 is a half sectional view showing the relationship between the input side disc, the output side disc, and the trunnion at the time of maximum deceleration and the time of maximum acceleration.

FIG. 7 is an end view of a trunnion pivotally supporting a power roller according to a second embodiment of the present invention.

FIG. 8 is a half sectional view showing a relationship between a pressing device, an input side disc, an output side disc and a trunnion, showing a third embodiment of the present invention.

FIG. 9 is a side view showing a basic configuration of a toroidal type continuously variable transmission, which is a target of the present invention, in a state of maximum deceleration.

FIG. 10 is a side view showing the same state at the time of maximum acceleration.

FIG. 11 is an end view of a trunnion that has been conventionally used.

FIG. 12 is a side view of the same.

FIG. 13 is a partial perspective view of the same.

FIG. 14 is a cross-sectional view showing another example of the conventional structure.

FIG. 15 is an end view of a conventionally proposed trunnion.

FIG. 16 is a side view of the same.

FIG. 17 is a partial perspective view of the same.

[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 Circular Hole 8 Displacement Axis 9 Power Roller 9a Circumferential Surface 10 Pressurizing Device 11 Cam Plate 12 Cage 13 Roller 14 Cam Surface 15 Cam surface 16 Needle bearing 17 Housing 18 Hydraulic cylinder 19 Cylindrical surface part 20 Outer ring 21 Ball 22 Cage 24 Concave 25 Plate part 26 Main body part 27 Trunnion 28 Base part 29 Circular hole 30 Flat surface 31 Trunnion 32 Bent hole 34 Bent hole 35a, 35b Through hole 36 Inner half 37 Outer half 38 Between

Claims (1)

[Claims] 1. An input side disc, an output side disc which is arranged concentrically with the input side disc, and is rotatably supported with respect to the input side disc, and twists about central axes of both the input side disc and the output side disc. The trunnion swinging about a pair of pivot shafts at the position of, the displacement shaft supported by the trunnion, and the displacement shaft rotatably supported and sandwiched between the input side and output side disks. A power roller, the inner surfaces of the input side and output side disks facing each other are concave surfaces having an arcuate cross section, and the peripheral surface of the power roller is a spherical convex surface. In a toroidal type continuously variable transmission with abutting against, the trunnion enters between the inner side surfaces of both the input side and output side discs due to swinging about the pivot axis. Outside the part The surface exists diametrically inward with respect to the cylindrical surface that is in contact with each of the inner side surfaces with the pivot as the center, and the input side and the output side of the both disks are irrespective of the swinging around the pivot in the remainder of the trunnion. The toroidal type continuously variable transmission characterized in that the outer surface of the portion that does not enter between the inner side surfaces is present outside the cylindrical surface in the diametrical direction.