JP7775787B2 - Toroidal type continuously variable transmission - Google Patents

Description

The present invention relates to a toroidal-type continuously variable transmission that can be used in automobiles, aircraft generators, and transmissions for various industrial machines.

For example, a double-cavity toroidal continuously variable transmission used as an automobile transmission is configured as shown in Figures 6 and 7. As shown in Figure 6, an input shaft 1 is rotatably supported inside a casing 49, and two input side discs 2, 2 and two output side discs 3, 3 are attached to the outer periphery of this input shaft 1. An output gear (transmission gear) 4 is rotatably supported on the outer periphery of an intermediate portion of the input shaft 1. The output side discs 3, 3 are connected by spline connection to cylindrical flange portions (sleeves) 4a, 4a provided at the center of this output gear 4.
The input shaft 1 is rotationally driven by a drive shaft 22 via a loading cam type pressing device 12 provided between the input side disc 2 located on the left side in Fig. 6 and a cam plate (loading cam) 7. The output gear 4 is supported in a casing 49 via a partition wall 13 formed by joining two members, which allows the output gear 4 to rotate around the axis O of the input shaft 1 while preventing displacement in the direction of the axis O.

The output discs 3, 3 are supported for rotation around the axis O of the input shaft 1 by needle bearings 5, 5 interposed between them. The input disc 2 on the left side of FIG. 6 is supported on the input shaft 1 via a ball spline 6, while the input disc 2 on the right side of FIG. 6 is spline-connected to the input shaft 1, allowing these input discs 2 to rotate together with the input shaft 1. Power rollers 11 (see FIG. 7) are rotatably sandwiched between the inner surfaces (concave surfaces; also called traction surfaces) 2a, 2a of the input discs 2, 2 and the inner surfaces (concave surfaces; also called traction surfaces) 3a, 3a of the output discs 3, 3.

A stepped portion 2b is provided on the inner peripheral surface 2c of the input disc 2, located on the right side in Figure 6. A stepped portion 1b on the outer peripheral surface 1a of the input shaft 1 abuts against this stepped portion 2b, and the back surface of the input disc 2 (the right surface in Figure 6) abuts against a loading nut 9 threaded onto a threaded portion formed on the outer peripheral surface of the input shaft 1. This effectively prevents displacement of the input disc 2 in the direction of the axis O relative to the input shaft 1. A disc spring 8 is provided between the cam plate 7 and the flange 1d of the input shaft 1. This disc spring 8 applies a pressing force (preload) to the contact points between the concave surfaces 2a, 2a, 3a, 3a of the discs 2, 2, 3, 3 and the peripheral surfaces 11a, 11a of the power rollers 11, 11.

Figure 7 is a cross-sectional view taken along line A-A in Figure 6. As shown in Figure 7, a pair of trunnions 15, 15 are provided inside the casing 49, which swing around a pair of pivot shafts 14, 14 that are twisted relative to the input shaft 1. Note that the input shaft 1 is not shown in Figure 7. Each trunnion 15, 15 has a pair of bent wall portions 20, 20 at both ends of the support plate portion 16 in the longitudinal direction (vertical direction in Figure 7), which are bent toward the inner surface of the support plate portion 16. These bent wall portions 20, 20 form a recessed pocket P in each trunnion 15, 15 for accommodating the power roller 11. Furthermore, the pivot shafts 14, 14 are concentrically located on the outer surfaces of the bent wall portions 20, 20.

A circular hole 21 is formed in the center of the support plate portion 16, and this circular hole 21 supports the base end 23a of the displacement shaft 23. By swinging each trunnion 15, 15 around each pivot 14, 14, the inclination angle of the displacement shaft 23 supported in the center of each trunnion 15, 15 can be adjusted. Furthermore, each power roller 11 is rotatably supported around the tip end 23b of the displacement shaft 23 protruding from the inner surface of each trunnion 15, 15, and each power roller 11, 11 is sandwiched between each input side disk 2, 2 and each output side disk 3, 3. The base end 23a and tip end 23b of each displacement shaft 23, 23 are eccentric to each other.

The pivots 14 of each trunnion 15 are supported by a pair of yokes 23A and 23B, respectively, for swinging and axial displacement (vertical in Figure 7), with horizontal movement of the trunnions 15 restricted by the yokes 23A and 23B. Each yoke 23A and 23B is formed into a rectangular shape by pressing or forging metal such as steel. Four circular support holes 18 are provided at the four corners of each yoke 23A and 23B, and the pivots 14 at both ends of the trunnion 15 are supported in these support holes 18 via radial needle bearings 30 for swinging motion. A circular locking hole 19 is provided at the center of the width of each yoke 23A and 23B (horizontal in Figure 7), and the inner circumferential surface of this locking hole 19 is cylindrical, with a spherical post 64 or 68 fitted within. That is, the upper yoke 23A is supported so as to be able to swing freely by a spherical post 64 that is supported on the casing 49 via a fixed member 52, and the lower yoke 23B is supported so as to be able to swing freely by a spherical post 68 and the upper cylinder body 56 of the drive cylinder 31 that supports it.

The displacement shafts 23, 23 provided on each trunnion 15, 15 are located 180 degrees opposite each other with respect to the input shaft 1. Furthermore, the direction in which the tip end 23b of each of these displacement shafts 23, 23 is eccentric relative to the base end 23a is the same as the direction of rotation of the two disks 2, 2, 3, 3 (opposite directions in Figure 7). The eccentric direction is also approximately perpendicular to the direction in which the input shaft 1 is disposed. Therefore, each power roller 11, 11 is supported so that it can be slightly displaced in the longitudinal direction of the input shaft 1. As a result, even if each power roller 11, 11 tends to be displaced in the axial direction of the input shaft 1 due to elastic deformation of each component due to the thrust load generated by the pressing device 12, this displacement is absorbed without applying excessive force to each component.

Moreover, between the outer surface of the power roller 11 and the inner surface of the support plate portion 16 of the trunnion 15, thrust ball bearings (thrust bearings) 24 and thrust needle bearings 25 are provided, in order from the outer surface side of the power roller 11. Of these, the thrust ball bearings 24 support the thrust load applied to each power roller 11 while allowing each power roller 11 to rotate. Each thrust ball bearing 24 is composed of a plurality of balls (hereinafter referred to as rolling elements) 26, 26, an annular cage 27 that holds each rolling element 26, 26 for free roll, and an annular outer ring 28. The inner ring raceway of each thrust ball bearing 24 is formed on the outer surface (large end face) of each power roller 11, and the outer ring raceway is formed on the inner surface of each outer ring 28.

The thrust needle bearings 25 are sandwiched between the inner surface of the support plate portion 16 of the trunnion 15 and the outer surface of the outer ring 28. These thrust needle bearings 25 support the thrust load applied to each outer ring 28 from the power rollers 11, while allowing the power rollers 11 and outer rings 28 to oscillate around the base end 23a of each displacement shaft 23.

Furthermore, a drive rod (trunnion shaft) 29 is provided at one end (lower end in Figure 7) of each trunnion 15, and a drive piston (hydraulic piston) 33 is fixed to the outer surface of the middle portion of each drive rod 29. Each of these drive pistons 33 is oil-tightly fitted into a drive cylinder 31 composed of an upper cylinder body 56 and a lower cylinder body 57. Each of these drive pistons 33 and drive cylinder 31 constitutes a drive unit 32 that displaces each trunnion 15 in the axial direction of the pivot shafts 14 of the trunnions 15.

In a toroidal-type continuously variable transmission configured in this manner, the rotation of the input shaft 1 is transmitted to the input discs 2, 2 via a pressing device 12. The rotation of these input discs 2, 2 is then transmitted to the output discs 3, 3 via a pair of power rollers 11, 11, and the rotation of these output discs 3, 3 is then extracted by the output gear 4.

To change the rotational speed ratio between the input shaft 1 and the output gear 4, the pair of drive pistons 33 are displaced in opposite directions. As the drive pistons 33 are displaced, the pair of trunnions 15 are displaced in opposite directions. For example, the power roller 11 on the left side of Figure 7 is displaced downward, and the power roller 11 on the right side of Figure 7 is displaced upward.
As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 11 a, 11 a of the power rollers 11, 11 and the inner surfaces 2 a, 2 a, 3 a, 3 a of the input side discs 2, 2 and the output side discs 3, 3 changes. Then, in accordance with the change in the direction of the force, the trunnions 15, 15 swing (tilt) in opposite directions to each other about the pivots 14, 14 pivotally supported by the yokes 23A, 23B.

As a result, the contact position between the peripheral surfaces 11a, 11a of each power roller 11, 11 and the inner surfaces 2a, 3a changes, changing the rotational speed ratio between the input shaft 1 and the output gear 4. Furthermore, when the torque transmitted between the input shaft 1 and the output gear 4 fluctuates and the amount of elastic deformation of each component changes, the power rollers 11, 11 and their associated outer rings 28, 28 rotate slightly around the base ends 23a, 23a of the displacement shafts 23, 23. The presence of thrust needle bearings 25, 25 between the outer surfaces of the outer rings 28, 28 and the inner surfaces of the support plates 16 that make up each trunnion 15, 15, ensures smooth rotation. Therefore, as mentioned above, only a small force is required to change the inclination angle of the displacement shafts 23, 23.

Japanese Patent Application Laid-Open No. 2004-347047 Japanese Patent Application Laid-Open No. 2003-166609

In a toroidal-type continuously variable transmission, a roller bearing or a cage and roller is interposed between a disk (input disk or output disk) and a shaft, thereby rotatably supporting the disk on the shaft. The disk and the shaft rotate in opposite directions, and the bearing between them must support the relative rotation. In a toroidal-type continuously variable transmission for aircraft, which is used at high speeds, the relative rotation speed of the bearing can reach a maximum of approximately 30,000 rpm. If the bearing cage comes into contact with a mating part (e.g., a retaining ring) that supports the axial position, there is a risk of seizure or retainer wear, which may ultimately lead to retainer or retainer breakage.
If the bearing cage breaks, the supporting disc and shaft will vibrate more, causing the toroidal continuously variable transmission to become out of sync and potentially making it impossible to transmit power. Furthermore, when the cage breaks, it may impact surrounding components, potentially causing the disc or shaft to crack.
Furthermore, if the retaining ring of a bearing breaks, the bearing will move axially, causing the bearing rollers to roll in places other than their intended raceway, which could lead to early failure of the bearing.
As mentioned above, retaining rings rotate at high speeds, generating centrifugal force. To prevent the retaining ring from coming loose even if it deforms due to centrifugal force, it is advantageous to place the retaining ring on the hole side, i.e., on the inner diameter side of the disk. However, if a retaining ring groove (fitting groove) for fitting the retaining ring is provided on the inner diameter surface of the disk, the retaining ring groove of the disk becomes a high-stress area, raising the risk of the disk cracking.

For example, in the prior art shown in Figure 8, the retainer 72 of the bearing 70 is supported in the axial direction by the splined step portion (axial end surface of the spline portion) 2d of the disk 2, a shim 73, and a retaining ring 74. Meanwhile, the disk's inner diameter surface 2c deforms inward due to the normal force from the power roller 11, causing high stress in the retaining ring groove 2e provided on the disk's inner diameter surface 2c. Disks 2 for aircraft rotate at approximately 20,000 rpm (over 300 Hz), and this deformation occurs twice per disk rotation, raising concerns about disk fatigue failure (disk cracking).

Therefore, a configuration in which a retaining ring is provided on the shaft 1A side is considered, but because the oil moves radially outward due to centrifugal force caused by high-speed rotation, there is a tendency for oil to be insufficient on the radially inner side, i.e., on the shaft side, and there is a possibility that oil will not be present at the contact point between the retaining ring on the shaft side and the shim (the part located between the cage & roller and the retaining ring).As a result, wear of the retaining ring and shim will progress due to oil film breakdown, and there is a risk of the retaining ring breaking.
In a toroidal type continuously variable transmission for aircraft, the shaft designated by the reference symbol 1A is an output shaft, and the input side disk 2 is rotatably supported by this output shaft 1A via a bearing 70.

The present invention was made in consideration of the above circumstances, and aims to provide a toroidal-type continuously variable transmission that does not cause oil film breakdown on the shaft side, suppresses the occurrence of high-stress areas on the disc, and prevents fatigue failure of the disc.

In order to achieve the above object, the toroidal type continuously variable transmission of the present invention is a toroidal type continuously variable transmission including a shaft, a first disc and a second disc provided on the shaft so as to be rotatable concentrically with each other and integrally with the shaft with their inner surfaces facing each other, and a power roller sandwiched between the two discs,
an oil chamber is provided between an outer diameter surface of the shaft and an inner diameter surface of the second disk, and a seal body is provided that forms an end of the oil chamber in the axial direction of the shaft and comes into contact with the inner diameter surface of the second disk;
a bearing that rotatably supports the second disk and the shaft is provided in the oil chamber,
fitting grooves extending in a circumferential direction of the shaft are provided on an outer diameter surface of the shaft so as to be spaced apart in the axial direction,
A retaining ring is fitted into the fitting groove to restrict movement of the seal body in the axial direction and in a direction away from the bearing.

Here, when the toroidal-type continuously variable transmission is in operation, oil is constantly supplied to the oil chamber, for example, from an oil supply hole formed inside the shaft.

In the present invention, a retaining ring that forms the axial end of the oil chamber and restricts axial movement of the seal body that contacts the inner diameter surface of the second disk away from the bearing is fitted into fitting grooves provided axially spaced apart on the outer diameter surface of the shaft, eliminating the need to form a retaining ring groove on the inner diameter surface of the second disk as in the prior art. This eliminates high stress areas on the second disk and prevents fatigue failure of the second disk.
In addition, since the oil chamber is formed by the outer diameter surface of the shaft, the inner diameter surface of the second disk, and the seal body, there is no oil film breakdown on the shaft side, and therefore an oil film is formed on the bearing provided in the oil chamber, the seal body facing the oil chamber, and the retaining ring that restricts the movement of the seal body, thereby suppressing wear caused by oil film breakdown.

In the above-described configuration of the present invention, the seal body includes a cylindrical member that is fitted onto the shaft with a predetermined gap therebetween, and a seal member that is provided on an outer peripheral surface of the cylindrical member and that is in oil-tight contact with the inner diameter surface of the second disk,
A surface of the cylindrical member that is closer to the inner diameter and faces the retaining ring may be in contact with the retaining ring.
The term "oil-tight" used herein means that "the sealing member (outer surface) fits loosely to the inner diameter surface of the second disc, and viscous oil is prevented or suppressed from passing between the sealing member (outer surface) and the inner diameter surface of the second disc," and this also applies to the following explanation.

Here, if too much oil is supplied to the oil chamber, the dynamic torque (rotational resistance) of the shaft and second disk will increase, so to prevent this increase, it is preferable to adjust the amount of oil leaking (discharged) from the oil chamber by adjusting the size of the gap between the shaft and the cylindrical member.

With this configuration, the seal portion of the seal body is in oil-tight contact with the inner diameter surface of the second disk, and the surface of the cylindrical member facing the retaining ring near the inner diameter is in contact with the retaining ring. As a result, oil supplied to the oil chamber is discharged from the gap between the cylindrical member (its inner diameter surface) and the shaft and supplied to the contact point between the cylindrical member and the retaining ring. This reduces wear at the contact point between the retaining ring and the cylindrical member.

The toroidal type continuously variable transmission of the present invention is a toroidal type continuously variable transmission including a shaft, a first disc and a second disc provided on the shaft so as to be rotatable concentrically with each other and integrally with the shaft with their inner surfaces facing each other, and a power roller sandwiched between the first and second discs,
an oil chamber is provided between an outer diameter surface of the shaft and an inner diameter surface of the second disk, and an annular plate-shaped seal member is provided which forms an end of the oil chamber in the axial direction of the shaft and is in oil-tight contact with the inner diameter surface of the second disk;
fitting grooves extending in a circumferential direction of the shaft are provided on an outer diameter surface of the shaft so as to be spaced apart in the axial direction,
A seal member is fitted into the fitting groove,
The shaft and the second disk are rotatably supported by the oil pressure in the oil chamber.

Here, when the toroidal-type continuously variable transmission is in operation, oil is constantly supplied to the oil chamber, for example, from an oil supply hole formed inside the shaft.

In the present invention, the axial ends of the oil chambers are formed in fitting grooves provided axially spaced apart on the outer diameter surface of the shaft, and seal members that contact the inner diameter surface of the second disk in an oil-tight manner are fitted into these fitting grooves, eliminating the need to form a retaining ring groove on the inner diameter surface of the second disk as in the past. This eliminates high-stress areas on the second disk, preventing fatigue failure of the second disk.
Furthermore, since the oil chamber is formed by the outer diameter surface of the shaft, the inner diameter surface of the second disk, and the seal member, there is no oil film breakdown on the shaft side, and therefore an oil film is formed on the seal member facing the oil chamber, thereby suppressing wear caused by oil film breakdown.
Furthermore, since the shaft and the two discs are rotatably supported by the oil pressure in the oil chamber, there is no need to provide a bearing between the shaft and the second disc to rotatably support them, which reduces the number of parts.
In addition, since the seal member is in oil-tight contact with the inner diameter surface of the second disc, the oil filled in the oil chamber does not leak from between the seal member and the second disc, and the oil pressure in the oil chamber can be maintained constant.

This invention prevents oil film rupture on the shaft side and suppresses the occurrence of high-stress areas on the disk (second disk), preventing fatigue failure of the disk.

1 is a cross-sectional view showing an overall outline of a toroidal-type continuously variable transmission according to a first embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2 according to the first embodiment. FIG. FIG. 10 is a cross-sectional view of a main portion of a toroidal-type continuously variable transmission according to a second embodiment of the present invention. FIG. 1 is a cross-sectional view showing an example of a conventional toroidal type continuously variable transmission. FIG. 7 is a cross-sectional view taken along line AA in FIG. 6. FIG. 1 is an enlarged cross-sectional view of a main portion of an example of a conventional toroidal-type continuously variable transmission for aircraft.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
The toroidal type continuously variable transmission of this embodiment is a transmission used in an aircraft generator, and changes the rotation speed of the aircraft engine, which varies, to a constant rotation speed and outputs it to the generator.
FIG. 1 is a cross-sectional view showing an outline of the entire toroidal type continuously variable transmission according to the first embodiment, FIG. 2 is a cross-sectional view of the main part of the same, and FIG. 3 is an enlarged cross-sectional view of the main part in FIG.
6 and 7, the output side disc 3 is rotatably supported by the input shaft 1 via a bearing 5. In this embodiment, however, the input side disc 2 is rotatably supported by the output shaft 1A via a bearing 70. However, the toroidal-type continuously variable transmission of this embodiment and the conventional toroidal-type continuously variable transmission share the same configuration, such as the power roller 11 sandwiched between the input side disc 2 and the output side disc 3, and the pressing device 12 that presses one of the input side disc 2 and the output side disc 3 (2), and therefore a description thereof will be omitted. Also, hatching is omitted in FIG. 1.

As described above, the toroidal type continuously variable transmission of this embodiment is a double-cavity half-toroidal type continuously variable transmission for aircraft (power generators), in which the input side disc (second disc) 2 and output side disc (first disc) 3, which are arranged in one cavity, are attached around the output shaft (shaft) 1A, and the input side disc (second disc) 2 and output side disc (first disc) 3, which are arranged in the other cavity, are attached around the output shaft (shaft) 1A.
The output side disc 3 is rotatable integrally with the output shaft 1A, and the input side disc 2 is rotatable relative to the output shaft 1A via a bearing 70. A power roller 11 is provided between the input side disc 2 and the output side disc 3, and the power roller 11 is sandwiched between the two discs 2, 3.
In this embodiment, the output side disc 3 is pressed against the input side disc 2 by a pressing device 12 .

2 to 4, the bearing 70 includes a plurality of cylindrical rollers 71 that can roll between the output shaft 1A and the input-side disk 2, and a cylindrical cage 72 that is attached to the output shaft 1A and that rotatably holds the plurality of rollers 71. The rollers 71 are in rolling contact with the outer diameter surface of the output shaft 1A and the inner diameter surface of the input-side disk 2.
A plurality of retaining holes 72d are formed at predetermined equal angular intervals on the outer peripheral surface (outer diameter surface) 72a of the retainer 72, opening in the radial direction of the retainer 72. Each retaining hole 72d is capable of rotatably holding a roller 71 that rolls between the output shaft 1A and the input side disk 2.

As shown in FIGS. 2 and 3, the bearing 70 is provided in an oil chamber 50 (described later) provided between the output shaft 1A and the input side disc 2.
The input side disc 2 has a axial hole 2A in its radial center that has a circular cross section and extends in the axial direction, and the output shaft 1A is inserted through this axial hole 2A. One end of the axial hole 2A opens on the small end face side of the input side disc 2 (the right side in the axial direction in Figure 2), and the other end opens on the large end face side of the input side disc 2 (the left side in the axial direction in Figure 2).

1, an input gear 40 is provided between the pair of input side discs 2, 2. For example, rotational force from the rotating shaft of a turbine of an engine is transmitted to the input gear 40 via gears or the like.
As shown in Fig. 2, the input gear 40 includes a gear portion 41 disposed outside (axially outward from) the input-side disc 2, and a cylindrical sleeve 42 provided at the right end of the gear portion 41 on the radially central side (the output shaft 1A side in Fig. 2). The sleeve 42 is disposed coaxially with the axial hole 2A of the input-side disc 2, and approximately half of the tip end of the sleeve 42 is inserted into the axial hole 2A. As shown in Fig. 1, a sleeve 42 similar to the sleeve 42 is provided symmetrically at the left end of the gear portion 41 on the radially central side, and this sleeve 42 is similarly inserted into the axial hole 2A of the input-side disc 2 provided in the other cavity located on the left side of the gear portion 41.

As shown in FIG. 2, the outer diameter surface of the tip of the sleeve 42 is provided with a spline portion 45a having a radially uneven shape that extends (continuously) along the circumferential direction and also extends in the axial direction.
On the other hand, an inner diameter side spline portion 45b having a radially uneven shape extending (continuously) along the circumferential direction and extending axially is provided on the inner diameter surface radially opposing the spline portion 45a of the axial hole 2A of the input side disk 2. The inner diameter side spline portion 45b and the spline portion 45a have approximately the same length in the axial direction.
Then, by spline-engagement between this inner diameter side spline portion 45b and the outer diameter side spline portion 45a of the sleeve 42, the rotation of the input gear 40 is transmitted to the input side disc 2 via the sleeve 42, and the rotation of this input side disc 2 is transmitted to the output shaft 1A via the power roller 11 and the output side disc 3.

In this embodiment, as shown in Figures 2 and 3, an oil chamber 50 is provided between the outer diameter surface of the output shaft 1A and the inner diameter surface of the input side disc (second disc) 2, closer to the small end face of the input side disc 2 than the tip of the sleeve 42. At both axial ends of this oil chamber 50 (axial direction of the output shaft 1A), seal bodies 51, 51 are provided facing and spaced apart in the axial direction. Therefore, the area surrounded by the pair of seal bodies 51, 51, the outer diameter surface of the output shaft 1A, and the inner diameter surface of the input side disc 2 forms the oil chamber 50. The bearing 70 is provided in this oil chamber 50.

The seal body 51 comprises a cylindrical iron member 51a that is fitted onto the output shaft 1A with a predetermined radial gap S, and a seal member 51b that is attached to the outer surface of the cylindrical member 51a and that makes oil-tight contact with the inner diameter surface of the input side disc 2. A groove 51c is formed along the circumferential direction on the outer surface of the cylindrical member 51a, and the inner peripheral portion of a ring-shaped seal member 51b is fitted into this groove 51c. This seal member 51b makes oil-tight contact with the inner diameter surface of the input side disc 2. As the input side disc 2 rotates around the output shaft 1A, the seal member 51b makes oil-tight sliding contact with the inner diameter surface of the rotating input side disc 2. The seal member 51b is formed, for example, from an O-ring or a resin ring-shaped seal material.

Furthermore, fitting grooves 1g, 1g extending circumferentially of the output shaft 1A are provided on the outer diameter surface of the output shaft 1A at intervals in the axial direction. The inner peripheral portion of a circular plate-shaped retaining ring 53 is fitted into the fitting groove 1g, and the outer peripheral portion of the retaining ring 53 protrudes radially outward beyond the outer diameter surface of the output shaft 1A and the inner diameter surface of the cylindrical member 51a.
The retaining rings 53 restrict movement of the seal bodies 51 in the axial direction and in a direction away from the bearing 70 (in FIG. 3 , the right-side seal body 51 is to the right, and the left-side seal body 51 is to the left). That is, the surface of the seal body 51 that is closer to the inner diameter of the cylindrical member 51 a and faces the retaining ring 53 abuts against the retaining ring 53, thereby restricting movement of the seal body 51 in the axial direction and in a direction away from the bearing 70. That is, in FIG. 3 , the right-side retaining ring 53 restricts movement of the right-side seal body 51 to the right, and the left-side retaining ring 53 restricts movement of the left-side seal body 51 to the left.

In addition, an oil passage 1e extending in the axial direction is provided in the radial center of the output shaft 1A, and a plurality of oil supply holes 1f extending radially from the oil passage 1e are provided at predetermined intervals in the circumferential direction.
The oil supply hole 1f opens to the oil chamber 50 on the outer diameter surface of the output shaft 1A. Therefore, oil is constantly supplied to the oil chamber 50 through the oil passage 1e and the oil supply hole 1f when the toroidal-type continuously variable transmission is in operation. As described above, the bearing 70 is provided in the oil chamber 50.
The oil supplied to this oil chamber 50 is then supplied to the bearing 70, the outer diameter surface of the output shaft 1A supported by the bearing 70, and the inner diameter surface of the input-side disc 2. Furthermore, since a gap S is provided between the inner diameter surface of the cylindrical member 51a of the seal body 51 and the output shaft 1A, the oil supplied to the oil chamber 50 is discharged through the gap S and is supplied to the contact portion between the retaining ring 53 and the cylindrical member 51a of the seal body 51. This flow of oil is indicated by arrows in Figure 3.
If excessive oil is supplied to the oil chamber 50, the dynamic torque (rotational resistance) of the output shaft 1A and the input side disk 2 will increase. To prevent this increase, the amount of oil leaking (discharged) from the oil chamber 50 is adjusted by adjusting the size of the gap S between the output shaft 1A and the cylindrical member 51a.

According to the first embodiment, the retaining rings 53, 53 that restrict movement of the seal body 51 that forms the axial end of the oil chamber 50 in the axial direction of the output shaft 1A and in the direction away from the bearing 70 are fitted into the fitting grooves 1g, 1g provided axially spaced apart on the outer diameter surface of the output shaft 1A, so there is no need to provide a retaining ring groove on the inner diameter surface of the input side disc 2. As a result, high stress areas are eliminated from the input side disc 2, and fatigue failure of the input side disc 2 can be prevented.
Furthermore, since the oil chamber 50 is formed by the outer diameter surface of the output shaft 1A, the inner diameter surface of the input side disc 2, and the seal bodies 51, 51, there is no oil film breakdown on the output shaft 1A side. Therefore, an oil film is formed on the bearing 70 provided in the oil chamber 50, the seal body 51 facing the oil chamber 50, and the retaining ring 53 that restricts the movement of the seal body 51, thereby suppressing wear due to oil film breakdown.

The seal body 51 comprises a cylindrical member 51a that is fitted onto the output shaft 1A with a predetermined gap S, and a seal member 51b that is attached to the outer surface of the cylindrical member 51a and that is in oil-tight contact with the inner diameter surface of the input-side disc 2. The surface of the cylindrical member 51a closest to the inner diameter and facing the retaining ring 53 abuts against the retaining ring 53, so that oil supplied to the oil chamber 50 is discharged through the gap S between the inner diameter surface of the cylindrical member 51a and the output shaft 1A and is supplied to the abutment (contact portion) between the cylindrical member 51a and the retaining ring 53. This reduces wear at the abutment portion between the retaining ring 53 and the cylindrical member 51a.

Second Embodiment
5 is a cross-sectional view showing the main parts of a toroidal-type continuously variable transmission according to the second embodiment. The second embodiment differs from the first embodiment in that the input disc 2 and the output shaft 1A are rotatably supported by the oil pressure in the oil chamber 60, without providing a bearing between the outer diameter surface of the output shaft 1A and the inner diameter surface of the input disc 2. Therefore, the following will focus on this point, and the same components as those in the first embodiment will be designated by the same reference numerals and their description may be omitted.

In the second embodiment, an oil chamber 60 is provided between the outer diameter surface of the output shaft 1A and the input side disc 2, on the small end face side of the input side disc 2 from the tip end portion of the sleeve 42.
Seal members 61, 61 are provided axially opposite and spaced apart at both axial ends of the oil chamber 60 (axial direction of the output shaft 1A). Therefore, the area surrounded by the pair of seal members 61, 61, the outer diameter surface of the output shaft 1A, and the inner diameter surface of the input-side disc 2 forms the oil chamber 60.

The seal member 61 is formed in the shape of an annular plate, and is formed, for example, from a resin ring-shaped seal material. This seal member 61 is in oil-tight contact with the inner diameter surface of the input side disc 2. Since the input side disc 2 rotates around the output shaft 1A, the seal member 61 is in oil-tight sliding contact with the inner diameter surface of the rotating input side disc 2.
Additionally, fitting grooves 1h, 1h extending circumferentially of the output shaft 1A are provided on the outer diameter surface of the output shaft 1A at intervals in the axial direction. The inner peripheral portion of an annular plate-shaped seal member 61 is fitted into the fitting groove 1h, thereby restricting axial movement of the seal member 61. In other words, in FIG. 5, the right fitting groove 1h restricts rightward movement of the right seal member 61, and the left fitting groove 1h restricts leftward movement of the left seal member 61.

Also, as in the first embodiment, the output shaft 1A has an oil passage 1e extending axially in the radial center, and a plurality of oil supply holes 1f extending radially from the oil passage 1e are provided at predetermined intervals around the circumference.
The oil supply hole 1f opens into the oil chamber 60 on the outer diameter surface of the output shaft 1A. Therefore, oil is constantly supplied to the oil chamber 60 through the oil passage 1e and the oil supply hole 1f when the toroidal type continuously variable transmission is in operation.
The input side disc 2 and the output shaft 1A are rotatably supported by the oil pressure of the oil supplied to this oil chamber 60. This suppresses radial movement and resonance of the output shaft 1A.

According to the second embodiment, the seal members 61, 61 that form the axial ends of the oil chamber 60 and that contact oil-tightly with the inner diameter surface of the input side disc 2 are fitted into fitting grooves 1h, 1h that are provided axially spaced apart on the outer diameter surface of the output shaft 1A, eliminating the need to provide a retaining ring groove on the inner diameter surface of the input side disc 2. This eliminates high stress areas on the input side disc 2, preventing fatigue failure of the input side disc 2.
Furthermore, the oil chamber 60 is formed by the outer diameter surface of the output shaft 1A, the inner diameter surface of the input side disc 2, and the seal members 61, 61, so there is no oil film breakdown on the output shaft 1A side. Therefore, an oil film is formed on the seal members 61, 61 facing the oil chamber 60, so there is no oil film breakdown and wear due to oil film breakdown can be suppressed.

Furthermore, the seal member 61 is formed in the shape of an annular plate, with its inner periphery fitted into the fitting groove 1h and its outer periphery in oil-tight contact with the inner diameter surface of the input side disc 2. This prevents the oil filled in the oil chamber 60 from leaking between the seal member 61 and the input side disc 2, and maintains a constant oil pressure within the oil chamber 60.

In the first and second embodiments, the present invention has been described as being applied to a toroidal type continuously variable transmission for aircraft, but the present invention can also be applied to other uses (for example, automobile transmissions).
Furthermore, in the first and second embodiments, the present invention has been described with reference to an example in which it is applied to a double-cavity half-toroidal continuously variable transmission. However, the present invention is not limited to this, and can also be applied to a double-cavity full-toroidal continuously variable transmission, and further, can also be applied to a single-cavity half-toroidal continuously variable transmission, or a single-cavity full-toroidal continuously variable transmission.

Furthermore, while the first and second embodiments have been described using an example in which the output disc 3 is pressed by a pressing device 12, in a toroidal-type continuously variable transmission, the input/output relationship between the input disc and the output disc may be reversed. Therefore, the present invention can also be applied to a case in which the input disc 2 is pressed by a pressing device 12. In other words, as shown in Figures 6 and 7, the present invention can also be applied to a toroidal-type continuously variable transmission that includes an input shaft 1, an input disc 2 that is splined to the input shaft 1 by a ball spline and rotates integrally with the input shaft 1, and an output disc 3 that faces the input disc 2 and is rotatable relative to the input shaft 1.

1A output shaft (shaft)
1g, 1h Fitting groove 2 Input side disc (second disc)
3. Output disk (first disk)
11 Power roller 50, 60 Oil chamber 51 Seal body 51a Cylindrical member 51b Seal member 53 Retaining ring 61 Seal member 70 Bearing 72 Cage

Claims (3)

A toroidal type continuously variable transmission comprising: a shaft; a first disk and a second disk rotatable relative to the shaft, the first disk and the second disk being concentric with each other and rotatable integrally with the shaft with their inner surfaces facing each other; and a power roller sandwiched between the first and second disks,
an oil chamber is provided between an outer diameter surface of the shaft and an inner diameter surface of the second disk, and a seal body is provided that forms an end of the oil chamber in the axial direction of the shaft and comes into contact with the inner diameter surface of the second disk;
a bearing that rotatably supports the second disk and the shaft is provided in the oil chamber,
fitting grooves extending in a circumferential direction of the shaft are provided on an outer diameter surface of the shaft so as to be spaced apart in the axial direction,
a retaining ring fitted into the fitting groove to restrict movement of the seal body in the axial direction and in a direction away from the bearing; the seal body includes a cylindrical member that is fitted onto the shaft with a predetermined gap therebetween, and a seal member that is provided on an outer peripheral surface of the cylindrical member and that is in oil-tight contact with the inner diameter surface of the second disk,
2. The toroidal type continuously variable transmission according to claim 1, wherein a surface of the cylindrical member that faces the snap ring and is closer to the inner diameter of the cylindrical member abuts against the snap ring. A toroidal type continuously variable transmission comprising: a shaft; a first disk and a second disk rotatable relative to the shaft, the first disk and the second disk being concentric with each other and rotatable integrally with the shaft with their inner surfaces facing each other; and a power roller sandwiched between the first and second disks,
an oil chamber is provided between an outer diameter surface of the shaft and an inner diameter surface of the second disk, and an annular plate-shaped seal member is provided which forms an end of the oil chamber in the axial direction of the shaft and is in oil-tight contact with the inner diameter surface of the second disk;
fitting grooves extending in a circumferential direction of the shaft are provided on an outer diameter surface of the shaft so as to be spaced apart in the axial direction,
A seal member is fitted into the fitting groove,
a toroidal-type continuously variable transmission, wherein the shaft and the second disc are rotatably supported by hydraulic pressure in the oil chamber;