JP4110645B2 - Toroidal continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a toroidal-type continuously variable transmission used as a transmission for an automobile, for example, and prevents a stress from being applied to a component member, thereby realizing a structure having sufficient durability. .
[0002]
[Prior art]
The use of a toroidal continuously variable transmission as schematically shown in FIGS. This toroidal continuously variable transmission, for example, as disclosed in Japanese Utility Model Laid-Open No. 62-71465, supports an input side disk 2 concentrically with an input shaft 1, and outputs arranged concentrically with the input shaft 1. An output side disk 4 is fixed to the end of the shaft 3. Trunnions 6 and 6 swinging around the pivot shafts 5 and 5 are provided at intermediate positions in the axial direction of the input side and output side discs 2 and 4 inside the casing containing the toroidal type continuously variable transmission. . Each of the pivots 5 and 5 is in a twisted position perpendicular to the direction of the center axis of the input shaft 1 and the output shaft 3 and not intersecting with the center axis.
That is, these trunnions 6 and 6 are provided with the pivots 5 and 5 concentrically with each other on the outer surfaces of both ends. In addition, the base portions of the displacement shafts 7 and 7 are supported at intermediate portions of the trunnions 6 and 6, and the trunnions 6 and 6 are swung around the pivot shafts 5 and 5, so that the respective displacements are displaced. The inclination angle of the shafts 7 and 7 can be freely adjusted. Power rollers 8 and 8 are rotatably supported around the displacement shafts 7 and 7 supported by the trunnions 6 and 6, respectively. Each of these power rollers 8 and 8 is sandwiched between inner surfaces 2a and 4a of the input side and output side disks 2 and 4 facing each other. Each of these inner side surfaces 2a, 4a has a concave surface obtained by rotating a circular arc with the pivot axis 5 as the center. And the peripheral surfaces 8a and 8a of each said power roller 8 and 8 formed in the spherical convex surface are made to contact | abut to the said inner surface 2a and 4a.
[0004]
A loading cam type pressing device 9 is provided between the input shaft 1 and the input side disc 2, and the pressing device 9 allows the input side disc 2 to be elastically pressed toward the output side disc 4. . The pressing device 9 includes a cam plate 10 that rotates together with the input shaft 1 and a plurality of (for example, four) rollers 12 and 12 that are rotatably held by a cage 11. On one side surface (right side surface in FIGS. 8 to 9) of the cam plate 10, a cam surface 13 that is uneven in the circumferential direction is formed, and the outer side surface of the input side disk 2 (left side surface in FIGS. 8 to 9). ) Also has a cam surface 14 having a similar shape. The plurality of rollers 12 and 12 are supported so as to be rotatable about the radial axis with respect to the center of the input shaft 1.
[0005]
When the toroidal type continuously variable transmission configured as described above is used, when the cam plate 10 rotates with the rotation of the input shaft 1, the cam surface 13 moves the rollers 12, 12 to the outside of the input side disk 2. The cam surface 14 formed on the side surface is pressed. As a result, the input-side disk 2 is pressed against the plurality of power rollers 8 and 8 and at the same time, based on the pressing force between the cam surfaces 13 and 14 and the plurality of rollers 12 and 12, the input disk 2 is pressed. The side disk 2 rotates. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 through the plurality of power rollers 8, 8, and the output shaft 3 fixed to the output side disk 4 rotates.
[0006]
When changing the rotational speed ratio (transmission ratio) between the input shaft 1 and the output shaft 3, and when first decelerating between the input shaft 1 and the output shaft 3, the pivots 5 and 5 are used as the centers. Each trunnion 6, 6 is swung in a predetermined direction. As shown in FIG. 8, the peripheral surfaces 8a and 8a of the power rollers 8 and 8 are formed on a portion near the center of the inner surface 2a of the input side disc 2 and a portion near the outer periphery of the inner surface 4a of the output side disc 4, respectively. The displacement shafts 7 and 7 are inclined so as to contact each other. On the other hand, when increasing the speed, the trunnions 6 and 6 are swung in the opposite directions around the pivots 5 and 5. The peripheral surfaces 8a and 8a of the power rollers 8 and 8 are formed on the outer peripheral portion of the inner side surface 2a of the input side disc 2 and the central portion of the inner side surface 4a of the output side disc 4 as shown in FIG. The displacement shafts 7 and 7 are inclined so as to contact each other. If the inclination angle of each of the displacement shafts 7 and 7 is set intermediate between those shown in FIGS. 8 and 9, an intermediate transmission ratio can be obtained between the input shaft 1 and the output shaft 3.
[0007]
FIGS. 10 to 11 show an example of a more specific toroidal type continuously variable transmission described in the microfilm of Japanese Utility Model Application No. 63-69293 (Japanese Utility Model Laid-Open No. 1-173552). The input side disk 2 and the output side disk 4 are rotatably supported around needle-shaped input shafts 15 via needle bearings 16 and 16, respectively. Further, the cam plate 10 is spline-engaged with the outer peripheral surface of the end portion (left end portion in FIG. 10) of the input shaft 15 and the movement of the cam plate 10 in the direction away from the input side disk 2 is prevented by the flange portion 17. The cam plate 10 and the rollers 12 and 12 constitute a pressing device 9 that 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 coupled to the output side disk 4 by means of keys 19, 19, so that the output side disk 4 and the output gear 18 rotate in synchronization.
[0008]
The pivots 5, 5 provided at both ends of the pair of trunnions 6, 6 are respectively oscillated and displaced in the axial direction (front and back direction in FIG. 10, left and right direction in FIG. 11) on the pair of support plates 20, 20. Supports freely. The displacement shafts 7 and 7 are supported in the circular holes 21 and 21 formed in the intermediate portions of the trunnions 6 and 6. These displacement shafts 7 and 7 have support shaft portions 22 and 22 and pivot shaft portions 23 and 23 that are parallel to each other and eccentric, respectively. Of these, the support shaft portions 22 and 22 are rotatably supported inside the circular holes 21 and 21 via radial needle bearings 24 and 24. Further, power rollers 8 and 8 are rotatably supported around the pivot shaft portions 23 and 23 via other radial needle bearings 25 and 25, respectively.
[0009]
The pair of displacement shafts 7 and 7 are provided at positions opposite to the input shaft 15 by 180 degrees. The direction in which the pivot shafts 23 and 23 of the displacement shafts 7 and 7 are eccentric with respect to the support shafts 22 and 22 is the same with respect to the rotational directions of the input side and output side disks 2 and 4. It is set as the direction (left-right reverse direction in FIG. 11). The eccentric direction is a direction substantially perpendicular to the direction in which the input shaft 15 is disposed. Accordingly, the power rollers 8 and 8 are supported so as to be slightly displaceable along the axial direction of the input shaft 15 (the left-right direction in FIG. 10 and the front-back direction in FIG. 11). As a result, the power rollers 8 and 8 tend to be displaced in the axial direction of the input shaft 15 due to elastic deformation of the constituent members based on a large load applied to the constituent members in the state of transmission of rotational force. Even in such a case, this displacement can be absorbed without applying an excessive force to each component.
[0010]
Further, the thrust ball bearings 26 and 26 and the thrust are arranged 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 and 6 in order from the outer surface of the power rollers 8 and 8. Needle bearings 27 and 27 are provided. Of these, the thrust ball bearings 26, 26 allow the power rollers 8, 8 to rotate while supporting a load in the thrust direction applied to the power rollers 8, 8. The thrust needle bearings 27, 27 support the thrust load applied to the outer rings 28, 28 constituting the thrust ball bearings 26, 26 from the power rollers 8, 8, respectively. 23 and 23 and the outer rings 28 and 28 are allowed to swing around the support shaft portions 22 and 22.
[0011]
Further, driving rods 29 and 29 are respectively coupled to one end portions (left end portions in FIG. 11) of the trunnions 6 and 6, and driving pistons 30 and 30 are fixed to the outer peripheral surfaces of the intermediate portions of the driving rods 29 and 29. Has been established. The drive pistons 30 and 30 are oil-tightly fitted in the drive cylinders 31 and 31, respectively.
[0012]
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 through a pair of power rollers 8, 8, and the rotation of the output side disk 4 is taken out from the output gear 18. When changing the rotational speed ratio between the input shaft 15 and the output gear 18, the pair of drive pistons 30, 30 are displaced in opposite directions. As the drive pistons 30 and 30 are displaced, the pair of trunnions 6 and 6 are respectively displaced in the opposite directions. For example, the lower power roller 8 in FIG. The power rollers 8 are displaced to the left in the figure. As a result, the direction of the tangential force acting on the contact portion between the peripheral surfaces 8a, 8a of the power rollers 8, 8 and the inner side surfaces 2a, 4a of the input side disk 2 and the output side disk 4 changes. To do. The trunnions 6 and 6 swing in opposite directions around the pivots 5 and 5 pivotally supported by the support plates 20 and 20 in accordance with the change in the direction of the force. As a result, as shown in FIGS. 8 to 9 described above, the contact position between the peripheral surfaces 8a and 8a of the power rollers 8 and 8 and the inner surfaces 2a and 4a is changed. The rotational speed ratio with the output gear 18 changes.
[0013]
When the rotational force is transmitted between the input shaft 15 and the output gear 18 in this way, the power rollers 8 and 8 are connected to the input shaft 15 based on the elastic deformation of the constituent members. The displacement shafts 7 and 7 that are displaced in the axial direction and pivotally support the power rollers 8 and 8 are slightly rotated around the support shaft portions 22 and 22. As a result of this rotation, the outer surfaces of the outer rings 28, 28 of the thrust ball bearings 26, 26 and the inner surfaces of the trunnions 6, 6 are relatively displaced. Since the thrust needle bearings 27, 27 exist between the outer surface and the inner surface, the force required for this relative displacement is small. Therefore, as described above, the force for changing the inclination angle of each displacement shaft 7, 7 can be small.
[0014]
[Problems to be solved by the invention]
In the case of the conventional toroidal-type continuously variable transmission, the area of the cross section (cross section shown in FIG. 10) of each trunnion 6, 6 in a plane extending in a direction perpendicular to the central axis direction of each pivot 5, 5 is In particular, the trunnions 6 and 6 were not determined in consideration of the rigidity. FIG. 12 shows an example of a trunnion shape that has been generally considered. An intermediate portion of the trunnion 6, that is, a portion between the bent portions 32, 32 formed at both ends in order to form the pivots 5, 5, is opposed to the outer surface of the power roller 8 (FIGS. 10 to 11). The cross-sectional area of the portion to be performed and the vicinity thereof is constant with respect to the axial directions of the pivots 5 and 5.
[0015]
On the other hand, the bending stress applied to each trunnion 6, 6 based on the thrust load applied to each power roller 8, 8 increases as the distance from each power roller 8, 8, which is the force application point, increases. Therefore, in order to prevent the trunnions 6 and 6 from being elastically deformed in the bending direction regardless of the thrust load, the section modulus of the trunnions 6 and 6 is set to the both ends close to the pivots 5 and 5. It is preferable to enlarge the closer part. On the other hand, conventionally, as described above, since the cross-sectional area of the intermediate portion is the same over the axial directions of the pivots 5 and 5, the bending rigidity of each portion cannot be set to an optimum value. That is, when it is intended to ensure sufficient bending rigidity at both ends, the bending rigidity at the center becomes excessive, and because of the wall thickness, the trunnions 6 and 6 and the input side disk 2 are formed at the center. Or not only does it easily interfere with the output-side disk 4, but the weight of the trunnions 6, 6 increases. On the other hand, if the bending rigidity of the central portion is suppressed to an appropriate value and the thickness of the intermediate portion is made small so that the central portion does not interfere with the input side disk 2 or the output side disk 4, the bending at the ends near both ends is reduced. Rigidity is insufficient, and the amount of elastic deformation of the trunnions 6 and 6 based on the thrust load becomes excessive, making it difficult to maintain the performance of the toroidal continuously variable transmission.
[0016]
That is, if the amount of elastic deformation of each trunnion 6, 6 is excessive, not only the durability of each trunnion 6, 6 itself is impaired, but the position of each power roller 8, 8 becomes unstable, and It becomes impossible to realize the transmission ratio. Further, the thrust load applied to the thrust ball bearings 26 and 26 for rotatably supporting the power rollers 8 and 8 becomes uneven in the circumferential direction, and an excessive surface pressure acts on a part of the raceway surface. As a result, the durability of the thrust ball bearings 26, 26 is impaired.
[0017]
As inventions related to the shape of the trunnion, there are those described in JP-A-8-178007, JP-A-4-96654, and 6-14603, but they do not solve the above-mentioned problems. . That is, what is described in Japanese Utility Model Laid-Open No. 4-96654 considers the improvement of the heat dissipation of the trunnion, and does not consider the balance between weight reduction and securing of rigidity. Further, those described in JP-A-8-178007 and JP-A-6-14603 are intended to improve the rigidity of the entire intermediate portion of the trunnion, and prevent the rigidity from becoming excessive. It is not a consideration for achieving both weight reduction and rigidity.
In view of such circumstances, the toroidal continuously variable transmission of the present invention has been invented to achieve both reduction in weight of the trunnion and securing of rigidity.
[0018]
[Means for solving the problems]
The toroidal-type continuously variable transmission of the present invention is similar to the above-described conventional toroidal-type continuously variable transmission, and both input side and output side disks are supported concentrically and independently of each other, and these input disks. A plurality of trunnions swinging around a pair of concentric axes that are concentric with each other, at a twisted position perpendicular to the direction of the center axis of both the discs on the side and output side, and not intersecting with the center axis; A displacement shaft supported by each trunnion, a power roller rotatably supported by each displacement shaft, and sandwiched between the inner surfaces of both the input side and output side disks, and an outer side of each of these power rollers A thrust bearing provided between the side surface and the inner side surface of each trunnion. The inner side surfaces of the input side and output side disks facing each other are concave surfaces each having a circular arc cross section, and the peripheral surfaces of the power rollers are spherical convex surfaces. It is made to contact the side.
In particular, in the toroidal-type continuously variable transmission of the present invention, a cross section of an intermediate portion of each trunnion in a plane extending in a direction perpendicular to the central axis direction of each pivot is considered . Assuming a solid structure with no holes or oil passage holes , the cross-sectional area of each trunnion in the vicinity of each displacement axis at the center of each trunnion is It is smaller than the cross-sectional area of the portion close to the pivot axis.
[0019]
[Action]
With the toroidal continuously variable transmission of the present invention configured as described above, the action of transmitting rotational force between the input side disk and the output side disk and the speed ratio between these two disks are changed. The operation is the same as that of the conventional toroidal type continuously variable transmission as described above.
In particular, in the case of the toroidal-type continuously variable transmission according to the present invention, the cross-sectional area of the intermediate portion of the trunnion is varied in the axial direction of the pivot. Can be optimized. For this reason, the elastic deformation of the trunnion can be suppressed without increasing the weight of the trunnion, and the performance required for the toroidal type continuously variable transmission can be exhibited.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
1 to 7 show an example of an embodiment of the present invention. The feature of the present invention is that the rigidity of the trunnion 6a extending in the axial direction of the pivot shafts 5 and 5 is set to an optimum value in any portion, so that the weight of the trunnion 6a is not increased, and the trunnion 6a The input side disk 2 and the output side disk 4 do not easily interfere with each other, and the trunnion 6a has a structure for suppressing elastic deformation. Since the structure and operation of other parts are the same as those of various toroidal-type continuously variable transmissions that have been known or considered, including the conventional structure described above, illustration and description of equivalent parts are omitted or simplified. In the following, the characteristic part of the present invention will be mainly described.
[0021]
The trunnion 6a formed by forging steel is formed with bent portions 32, 32 bent in the same direction at both end portions of the intermediate portion 33, and the pivot shaft 5 on the outer surface of both bent portions 32, 32, 5 are integrally formed concentrically with each other. Then, when considering the cross-sectional shape of the intermediate portion 33 of the trunnion 6a in a plane extending in a direction perpendicular to the central axis direction of each of the pivot shafts 5 and 5, Are different. That is, in the case of the trunnion 6a constituting the toroidal type continuously variable transmission of the present invention, the cross-sectional area of the central portion of the trunnion 6a is smaller than the cross-sectional area of the portion near both ends of the trunnion 6a. A circular hole 21 for pivotally supporting the support shaft portion 22 (FIGS. 10 to 11) of the displacement shaft 7 is formed in the central portion of the trunnion 6a. However, in the case of defining the present invention. The cross-sectional area means a state before the circular hole 21 is formed, in other words, a state in which the circular hole 21 has a solid structure. Further, in order to lubricate each part, the oil passage hole 34 formed in the trunnion 6a is in a state before the oil passage hole 34 is formed (a state in which the part is assumed to be a solid structure). To tell.
[0022]
For this reason, in the illustrated example, concave portions 35 are formed on both side surfaces of the central portion of the trunnion 6a, respectively, and the cross-sectional area of the central portion is set at the portion near both ends by the cross-sectional integral of the concave portions 35, 35. It is smaller than the cross-sectional area. The shape and formation position of each of the recesses 35 and 35 are regulated as follows. That is, when the trunnion 6a is assembled to a toroidal continuously variable transmission and the toroidal continuously variable transmission is operated, and the trunnion 6a is oscillated and displaced about the pivots 5 and 5 for shifting. The concave portions 35, 35 are formed in portions close to the outer peripheral edge portions of the input side and output side discs 2, 4 (FIG. 10). These concave portions 35 and 35 are formed in substantially the same shape as the outer peripheral edge portions of both disks 2 and 4 in order to prevent interference between the outer peripheral edge portions of both disks 2 and 4 and the trunnion 6a.
[0023]
Such recesses 35, 35 are formed on both side surfaces of the trunnion 6a while rotating a blade having substantially the same shape as the outer peripheral edge portions of the input side and output side discs 2, 4. That is, the blade is brought closer to the trunnion 6a in the same positional relationship as the disks 2 and 4 when the toroidal continuously variable transmission is operated. More specifically, the cutter is rotated in a direction in which the trunnion 6a and the outer peripheral edges of the disks 2 and 4 approach each other as the trunnion 6a swings around the pivots 5 and 5. In the meantime, it is brought closer to the both side surfaces and further cut. If the concave portions 35 and 35 are formed in this manner, the concave portions 35 and 35 having a relatively complicated shape can be easily processed.
[0024]
In the case of the toroidal-type continuously variable transmission of the present invention configured as described above, the cross-sectional area of the intermediate portion 33 of the trunnion 6a is varied in the axial direction of the pivot shafts 5 and 5. The section modulus of the intermediate portion 33 can be set to an optimum value for the required bending rigidity. That is, based on the thrust load applied to each of the power rollers 8 and 8 (FIGS. 10 to 11), the section modulus of the portion near both ends where a large bending stress is applied is increased, and the section coefficient of the center portion where only a relatively small bending stress is applied. Can be relatively small. For this reason, without increasing the weight of the trunnion 6a, the elastic deformation of the trunnion 6a can be suppressed and the performance required for the toroidal continuously variable transmission can be exhibited.
[0025]
Further, as in the example shown in the figure, the trunnions 6a are cut off by forming recesses 35, 35 on both sides of the trunnions 6a to prevent interference with the outer peripheral edges of the discs 2, 4. If the area is adjusted, the toroidal continuously variable transmission incorporating the trunnion 6a can be more effectively reduced in size and weight by effectively using the space. That is, as shown in FIG. 6, even when the trunnion 6a is greatly swung and displaced in order to increase the transmission ratio of the toroidal type continuously variable transmission, the trunnion 6a and the input side disk 2 (or the output side disk 4). ) Does not interfere with the outer periphery. For this reason, in order to ensure the bending rigidity of the trunnion 6a, the degree of freedom in designing the toroidal continuously variable transmission, such as increasing the width dimension and decreasing the thickness dimension, and correspondingly reducing the distance between the other members. As a result, there is room for reduction in size and weight as described above.
[0026]
Further, although not an essential requirement of the present invention, by forming the concave portions 35, 35, the width dimension of the central portion of the trunnion 6a is changed to a portion closer to both ends as shown by a chain line in FIG. It can also be larger than the width dimension. However, even in this case, by forming the concave portions 35, the thickness of the central portion is made smaller than the thickness of the portion near both ends as necessary, so that the cross-sectional area of the center portion is reduced at the portions near the both ends. Make it smaller than the cross-sectional area.
[0027]
In any case, if the width of the central portion of the trunnion 6a is increased, the outer rings 28 and 28 constituting the thrust ball bearings 26 and 26 for supporting the power rollers 8 and 8 (FIGS. 10 to 11). The outer surface of the outer ring 28 can be effectively backed up, and the durability of the outer rings 28 can be improved. That is, in order to prevent interference between the trunnion 6 (see FIG. 13 to be described below) and the outer peripheral edge portions of both the disks 2 and 4 without forming the concave portions 35 and 35, the width of the trunnion 6 is used. The whole must be made small enough to prevent interference. For this reason, as shown in FIG. 13, part of the pitch circle of the balls constituting the thrust ball bearing 26 protrudes from both side edges of the trunnion 6. In such a state, a large bending stress is applied to a portion of the outer ring 28 facing the both side edges of the trunnions 6, 6, which may deteriorate the durability of the outer ring 28. On the other hand, by forming the concave portions 35 and 35 as described above, the width dimension of the central portion of the trunnion 6a is increased, and the pitch circles of the balls constituting the thrust ball bearing 26 are arranged on both side edges of the trunnion 6a. If it backs up so that a part of this pitch circle may not be protruded from the both side edges of the trunnion 6a, it is possible to prevent bending stress from being applied to the outer ring 28 and to improve the durability of the outer ring 28. To improve performance.
[0028]
【The invention's effect】
Since the present invention is configured and operates as described above, it is possible to realize a toroidal-type continuously variable transmission that is compact and lightweight and has excellent durability, while achieving both weight reduction and rigidity securing of the trunnion.
[Brief description of the drawings]
FIG. 1 is a view of a trunnion constituting an example of an embodiment of the present invention as viewed from an inner surface side.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 in a state where a circular hole and an oil passage hole are not formed.
FIG. 3 is a sectional view taken along the line BB in FIG.
4 is a cross-sectional view taken along the line CC of FIG. 1 in a state where a circular hole and an oil passage hole are formed.
FIG. 5 is a perspective view of a trunnion, a part of which is omitted.
FIG. 6 is a view showing a relationship between a disc and a trunnion in an assembled state in a toroidal type continuously variable transmission.
FIG. 7 is a schematic view showing the relationship between the trunnion, the power roller, and the thrust ball bearing, as viewed from the inner surface side of the trunnion.
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 the same state at the maximum speed increase.
FIG. 10 is a sectional view showing an example of a specific structure of a toroidal-type continuously variable transmission.
11 is a sectional view taken along the line DD of FIG. 10;
FIG. 12 is a perspective view showing an example of a conventional trunnion with a part thereof omitted.
13 is a view similar to FIG. 7, showing a case of a conventional structure.
[Explanation of symbols]
DESCRIPTION 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 Pivot 6, 6a Trunnion 7 Displacement shaft 8 Power roller 8a Peripheral surface 9 Pressing device 10 Cam plate 11 Cage 12 Roller 13, 14 Cam Surface 15 Input shaft 16 Needle bearing 17 collar 18 output gear 19 key 20 support plate 21 circular hole 22 support shaft 23 pivot shaft 24, 25 radial needle bearing 26 thrust ball bearing 27 thrust needle bearing 28 outer ring 29 drive rod 30 Drive piston 31 Drive cylinder 32 Bent part 33 Intermediate part 34 Oil passage hole 35 Concave part

Claims (4)

The input side and output side disks supported concentrically and independently of each other, and the torsion that does not intersect the center axis in a direction perpendicular to the direction of the center axis of both the input side and output side disks. A plurality of trunnions swinging around a pair of concentric axes that are concentric with each other, a displacement shaft supported for each trunnion, and rotatably supported by each of these displacement shafts, the input side A power roller sandwiched between the inner side surfaces of the output side discs, and a thrust bearing provided between the outer side surface of each power roller and the inner side surface of each trunnion. The inner side surfaces of the both side disks facing each other are concave surfaces each having a circular arc cross section, and the peripheral surfaces of the respective power rollers are spherical convex surfaces, and these peripheral surfaces and the respective inner side surfaces are brought into contact with each other. Become In Idar type continuously variable transmission, consider the cross section of the middle portion of each trunnion of a plane extending perpendicular to the center axis of the respective pivot, the trunnions is inside the circular holes and oil passing hole If it is assumed that the solid structure is not provided , the cross-sectional area of the central portion of each trunnion in the vicinity of each of the displacement axes is a portion of the trunnion near both ends of each trunnion. A toroidal-type continuously variable transmission characterized by being smaller than the area. On both sides of the central part of each trunnion, the outer peripheral edge part of these two disks is placed on the part approaching the outer peripheral edge part of both the input side and output side disks as the trunnion swings about each pivot axis. The toroidal continuously variable transmission according to claim 1, wherein a recess is formed to prevent interference with each of the trunnions. The recess has a blade having substantially the same shape as the outer peripheral edge of both the input and output discs, and each trunnion and the both discs as the trunnions swing around the pivots with respect to each trunnion. The toroidal-type continuously variable transmission according to claim 2, wherein the toroidal-type continuously variable transmission is formed by approaching in a direction in which the outer peripheral edge portion approaches each other. The width of the central part of each trunnion is made larger than the width of the part near both ends, and the pitch circle of the ball constituting the thrust ball bearing for supporting the thrust load applied to each power roller is The toroidal type continuously variable transmission according to any one of claims 2 to 3, which is disposed between the two.

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