JPH09324841A - Troidal type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a loss torque through bearings at an input/output shaft over an entire rotating range. SOLUTION: Power rollers held in troid-shaped grooves formed at each of opposing surfaces of an input disc and an output disc, and an input shaft side bearing means and an output shaft side bearing for pivotally supporting each of an input shaft 14 and an output gear 26 within a casing 67 are constructed such that tapered roller bearings 1, 2, rolling members and thrust needle bearings having equal contact angles between the roller member and an outer ring and between the roller member and an inner ring are arranged in series, and they are selectively rotated in response to a degree of friction torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a bearing for an input / output shaft of a toroidal type continuously variable transmission used for a vehicle or the like.

[0002]

2. Description of the Related Art As a structure for supporting an input / output shaft of a toroidal-type continuously variable transmission, a structure as disclosed in Japanese Patent Application Laid-Open No. Sho 63-130953 is known.

[0003] This is a case where a driving force is transmitted from an input shaft to an output shaft (or an output gear) at a speed ratio according to a tilt angle of a power roller sandwiched between a pair of input disks and an output disk. In addition, an angular ball bearing that supports a clamping force in the thrust direction and a radial load is used to support the input / output shaft.

In the toroidal type continuously variable transmission, in order to prevent loss of transmission torque due to slippage of the power roller, the power roller and the input / output disk are pressed with a large force to maintain a high contact surface pressure (pressure). Although pressure-viscosity index α high oil, for example, traction oil is used,
In the case of an angular ball bearing that supports the input and output shafts, spin occurs with the rotation of the bearing, and the thrust in the thrust direction applied to the angular ball bearing by the reaction force that pinches and presses the power roller is extremely large. The contact surface pressure between the ball and groove of the bearing also becomes very high, for example, exceeding 1 GPa. At such a high pressure, the traction oil becomes semi-solid as described above. There is a problem that the efficiency of the toroidal-type continuously variable transmission is reduced due to the increase.

Therefore, the applicant of the present application has filed Japanese Patent Application No. 7-153.
No. 442 proposed a toroidal-type continuously variable transmission employing a tapered roller bearing in place of the angular ball bearing.

To explain this, as shown in FIG. 6, an input disk 1 having a toroidal groove on its opposite surface.
8, the output disk 20 is arranged coaxially with the input shaft 14, and by changing the inclination angle of the pair of power rollers 22, 22 pressed against the input disk 18 and the output disk 20, an arbitrary transmission ratio can be obtained. It can be set in a stepless manner.

The input disk 18 rotates substantially integrally with the input shaft 14 via a cam roller 79 and a cam flange 77. The input shaft 14 is a tapered roller bearing provided at a base end (right side in the figure). 1 and a needle bearing 66 provided at an end on the cam flange 77 side, and is rotatably supported by a casing 67.

On the other hand, the output disc 20 is connected to the output gear 26 on the rear side (right side in the drawing) and is rotatably supported relative to the input shaft 14, and the inner periphery of the output disc 20 and the input shaft 14 are connected to each other. It is rotatably supported by a needle bearing 73 interposed between the output gear 26 and the casing 67 and a tapered roller bearing 2 interposed between the output gear 26 and the casing 67.

The taper roller bearing 1 supporting the input shaft 14 and the taper roller bearing 2 supporting the output gear 26 constituting the output shaft are in contact with the outer rings 5 and 6 via the snap ring 9, and The taper roller bearing 1 on the shaft side is arranged so that the small diameter portion of the taper roller 7 faces the power roller 22 so as to support the thrust load in the direction of the power roller 22, while the taper roller bearing 2 on the output shaft side is provided.
Is arranged with the small diameter portion of the taper roller 8 facing the disc spring 70 so as to support the thrust load toward the disc spring 70 side.

The axial pressure that holds the power roller 22 between the input disk 18 and the output disk 20 is
And a cam roller 79 provided on the left end side of the input shaft 14.

The disc spring 70 is interposed between a spacer 68 of the tapered roller bearing 1 that supports the input shaft 14 and a loading nut 69 fastened to the base end side of the input shaft 14, and has a flange portion 68a. Via the spacer 68, the spacer 68 is urged to the left in the drawing.

Further, since the spacer 68 and the input shaft 14 are allowed to be displaced in the axial direction, the input shaft 14 is urged to the right side in the drawing by the reaction force of the disc spring 70, and the initial load for sandwiching the power roller 22 is obtained. To get

A thrust force for urging the input disc 18 to the right side in the drawing in accordance with the rotation of the input shaft 14 is provided between the cam flange 77 provided at the left end portion of the input shaft 14 in the drawing and the input disc 18. The generated cam roller 79 is interposed.

Therefore, the power roller 22 has a disc spring 70.
The input disk 18 and the output disk 20 rotate without slipping due to the initial load generated by the cam roller 79 and the axial thrust generated by the cam roller 79, transmitting torque from the input disk 18 to the output disk 20 and transmitting the input shaft 14. Roller bearings 1 and 2 that support the output gear 26
Supports the clamping pressure of the power roller 22 by axially pressing the outer rings 5 and 6 to each other through the spacer 9 and also supports the load in the radial direction.

The power roller 22 is rotatably supported by an eccentric shaft 80 provided on a trunnion 83 which is rotatable about its axis, and the power roller 22 is displaced in accordance with the displacement of the trunnion 83 in the axial direction (the penetrating direction in the drawing of the drawing). Tilt and input disk 18
The gear ratio is continuously changed by changing the contact radius between the motor and the output disk 20.

By supporting the input / output shafts by the tapered roller bearings 1 and 2, as shown in FIG. 7, for example, in the tapered roller bearing 2 on the output shaft side, the inner ring 4, the outer ring 6, and the tapered roller 8 have raceway surfaces 40. , in contact with 60, for the extended line of the rotation axis O _B of the taper roller 8, the extension line L _1, L ₂ of the raceway surfaces 40, 60 intersect at a point on the rotary axis O _a bearing,
The loss of torque of the continuously variable transmission is reduced by preventing the occurrence of spin as in the angular ball bearing. In the figure, γ,
γ ₁ and γ ₂ represent the contact angles of the taper roller 8 and the raceway surfaces 40 and 60, and although not shown, the input side taper roller bearing 1 is also similarly configured.

[0017]

By the way, in the toroidal type continuously variable transmission as described above, as shown in FIG. 7, since the contact angles γ ₁ and γ ₂ of the inner ring 4 and the outer ring 6 of the taper roller 8 are different from each other. In the taper roller 8, the large-diameter portion 8b generates a component force toward the large collar 41 of the inner ring 4, and the large-diameter portion 8b contacts the large collar 41 and slides to support the component force. Since there is no spin unlike the angular ball bearing, the torque loss due to the rolling of the taper roller 8 is smaller than that of the angular ball bearing, and a sufficient oil film is formed between the large flange 41 and the large diameter portion 8b of the taper roller 8. If so, the friction coefficient and the loss torque can be reduced.

However, in such a conventional toroidal type continuously variable transmission, the friction torque of the tapered roller bearing that supports the input / output shaft is "bearing".
Engineer No. 52 "(published by NTN Co., Ltd. in 1985), pp. 101-107, in the graph of FIG. 8 between the taper roller 8 and the raceway surfaces 40, 60 of the inner and outer races 4, 6. It is the sum of the rolling friction torque Mr and the sliding friction torque Ms generated between the large flange 41 and the large diameter portion 8b of the taper roller 8, and the rolling friction torque Mr rises as the rotation speed increases. The sliding friction torque Ms is large in a low rotation range (30 rpm or less) where the oil film is thin and is in metal contact, and has a characteristic that it decreases with an increase in rotation speed. Furthermore, as shown in FIG. The thrust torque of the tapered roller bearing increases in proportion to the magnitude of the load. Therefore, when the input / output shaft of the continuously variable transmission is supported, the power roller 22 is set as described above. Since a large thrust load for lifting the pressing is applied, the friction torque at low rotation region is increased, the loss torque at a low rotational speed range of the continuously variable transmission there is a problem that increases.

Therefore, the present invention has been made in view of the above problems, and reduces the torque loss due to the bearing of the input / output shaft in the entire rotation range of the toroidal type continuously variable transmission to improve the power transmission efficiency. With the goal.

[0020]

According to a first aspect of the present invention, there is provided an input disk connected to an input shaft, an output disk connected to an output shaft, and a toroidal shape formed on an opposing surface of the input / output disk. A power roller sandwiched between the grooves,
In a toroidal type continuously variable transmission including an input side bearing means and an output side bearing means for axially supporting the input shaft and the output shaft, respectively, at least one of the input side bearing means and the output side bearing means. On the other hand, a tapered roller bearing and a second bearing having the same contact angle between the rolling element and the outer race and the inner race are arranged in series.

In a second aspect based on the first aspect, the second bearing is a thrust needle bearing.

In a third aspect based on the first aspect, the second bearing is an angular ball bearing.

[0023]

Therefore, according to the first aspect of the invention, the thrust load corresponding to the clamping pressure of the power roller is applied to the input side bearing means and the output side bearing means, but at least one of these bearing means is provided with a rolling element. A tapered roller bearing that does not generate spin and a second bearing having the same contact angle between the rolling element and the outer ring and the inner ring are arranged in series to support the thrust load. The taper roller bearing has a thin lubricating oil film in the low rotation speed region of the friction torque, and the friction torque of sliding due to the contact between the flange and the rolling element is dominant and increases, but it increases as the rotation speed increases. The friction torque of the slip is reduced. Along with this, the friction torque due to the rolling of the rolling elements becomes dominant in the high rotation range, but as described above, the taper roller bearing has a small friction torque because the rolling of the rolling elements does not involve spin. On the other hand, since the contact angles of the second bearing are equal to each other and slippage does not occur, the friction torque does not become excessive even in the low rotation range. However, since the rolling element rolls with spin, the friction torque due to this rolling has a larger value than the friction torque due to the rolling of the taper roller bearing. Therefore, in the low rotation speed range, the friction torque of the second bearing is smaller than that of the tapered roller bearing.
Only the bearing rotates and receives a thrust load, but when the number of rotations increases, the friction torque of the second bearing becomes larger than the friction torque of the taper roller bearing due to the spin of the rolling elements, so that the contact torque becomes larger. Only the bearing can rotate to support the thrust load, and the tapered roller bearing and the second bearing selectively rotate according to the magnitude of the friction torque to prevent the friction torque from increasing in the low rotation range. However, the input / output shaft can be smoothly supported.

Further, in the second aspect of the invention, as in the first aspect of the invention, the thrust load applied to the input / output shaft is reduced by rotating only the thrust needle bearing, which has a relatively small friction torque in the low rotation range. Supports thrust load by rotating only the tapered roller bearing that supports, while the friction torque decreases relatively as the number of rotations increases, preventing the increase of friction torque in the low rotation range and smoothing the input / output shaft. Can be pivoted to.

The third invention, like the first invention, supports the thrust load applied to the input / output shaft by rotating only the angular ball bearing in which the friction torque becomes relatively small in the low rotation range. On the other hand, the friction torque becomes relatively smaller when the number of rotations increases. Only the tapered roller bearing rotates to support the thrust load and prevent the friction torque from increasing in the low rotation range, while smoothing the input / output shaft. Can be pivoted.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show a case where the present invention is applied to the toroidal type continuously variable transmission shown in FIG. 6 of the conventional example, in which the tapered roller bearings 1 and 2 are thrust needle bearings which receive a thrust load. With the respective
Others are almost the same as the above-mentioned conventional example, the same components are designated by the same reference numerals, and a duplicate description will be omitted.

The tapered roller bearing 1 supporting the input shaft 14 and the tapered roller bearing 2 supporting the output gear 26 on the output shaft side contact the outer rings 5 and 6 via the snap ring 9.

The inner ring 3 of the tapered roller bearing 1 is provided with a thrust needle bearing 11 and a radial needle bearing 1 interposed between the input shaft 14 and a spacer 68 connected in the rotational direction.
5, the inner ring 4 of the tapered roller bearing 2 is rotatably supported by a thrust needle bearing 12 and a radial needle bearing 16 which are interposed between the inner ring 4 and the output gear 26.

That is, as shown in FIG.
In the tapered roller bearing 1 that axially supports, the spacer 68 that transmits the initial load from the disc spring 70 is composed of a flange portion 68a protruding in the radial direction and a cylindrical portion 68b protruding toward the output gear 26 side. While the radial needle bearing 15 is interposed between the outer circumference of the portion 68b and the inner circumference of the inner ring 3 of the tapered roller bearing 1, between the end surface 68d of the flange portion 68a and the end surface 3a of the inner ring 3 that face each other, A thrust needle bearing 11 is interposed as a first bearing in which the rolling elements have the same contact angle with the outer ring and the inner ring.

The taper roller bearing 1 and thrust needle bearing 11 rotate selectively according to friction and receive a thrust load according to an initial load applied by the disc spring 70, as will be described later. The bearing 15 supports only the radial load while absorbing a minute relative displacement of the spacer 68 and the inner ring 3 in the axial direction.

The spacer 68 and the input shaft 14 are coupled in the rotational direction by the ball 100 engaged with the groove 14b formed on the input shaft 14 and the groove 68c formed on the inner circumference of the cylindrical portion 68b, while the shaft 68 is coupled with the shaft. Allows minute relative displacement in the direction. Similarly, the input disk 18 and the input shaft 14
1, the ball 1 engaged with the groove formed on the input shaft 14 and the groove formed on the inner circumference of the input disk 18 as shown in FIG.
While 01 is coupled in the rotational direction, it allows a minute relative displacement in the axial direction.

On the other hand, as shown in FIG. 2, the inner ring 4 of the tapered roller bearing 2 supporting the output shaft (output gear 26) has a cylindrical portion 26a protruding from the output gear 26 toward the disc spring 70 and the inner ring 4 of the inner ring 4. While the needle roller bearing 16 supporting only a radial load is interposed between the inner circumference and the inner circumference, between the side surface 26b of the output gear 26 and the end surface 4a of the inner ring 4 on the side where the outer diameter is large, A thrust needle bearing 12 is provided as a second bearing having the same contact angle between the rolling elements and the outer ring and the inner ring. The taper roller bearing 2 and the thrust needle bearing 12 selectively rotate according to friction, as will be described later. The radial needle bearing 16 does not absorb the minute relative displacement of the output gear 26 and the inner ring 4 in the axial direction, because the thrust load corresponding to the thrust applied by the cam roller 79 is received. Only the support Luo radial load.

Here, as in the prior art example, the input shaft side tapered roller bearing 1 is arranged with the small diameter portion of the tapered roller 7 facing the power roller 22 so as to support the thrust load in the direction of the power roller 22. On the other hand, the output shaft side taper roller bearing 2 is arranged with the small diameter portion of the taper roller 8 facing the disc spring 70 so as to support the thrust load toward the disc spring 70 side.

In the tapered roller bearing 2 on the output gear 26 side, as shown in FIG. 3, the large diameter portion 8b of the tapered roller 8 slides on the large flange 41 protruding from the inner ring 4 on the output gear 26 side. On the other hand, the inner ring 4 on the side of the small diameter portion 8a is provided with a small collar 42 for preventing the taper roller 8 from falling off, and the inner diameters of the inner ring raceway surface 40 and the outer ring raceway surface 60 are small on the small diameter portion 8a side. similar to FIG. 7, the relative rotation axis O _a of the input shaft 14 and the output gear 26 is coaxial with the inner ring 4 and outer ring 6, the contact angle rotation axis O _B is in a predetermined taper roller 8 gamma
In is inclined, the extension line of the rotation axis O _B orbital surface 40, 6
It intersects the extension lines L ₁ and L _{2 of} 0 at one point, and simultaneously supports the thrust load and the radial load without generating spin. Although not shown, the same applies to the tapered roller bearings 1 that support the input shaft 14. The tapered roller bearings 1 and 2 are provided with retainers 1a and 2a, respectively, so that the rolling elements have a predetermined circumference. To roll.

With the above construction, the operation will be described.

The input and output shafts that receive the reaction force of the thrust load that clamps and presses the power roller 22 are supported by the tapered roller bearings 1 and 2 and the thrust needle bearings 11 and 12 that are arranged in series via the inner rings 3 and 4. To be done.

Here, the friction of the tapered roller bearings 1 and 2 is the lubrication between the tapered rollers 7 and 8 and the large flanges 31 and 41 of the inner rings 3 and 4 as shown in FIGS. Low revs (for example, oil shortage and metal contact)
At 30 rpm or less), the sliding friction torque is large, and the sliding friction torque decreases and becomes less than the rolling friction torque as the rotation speed increases. That is, the rolling friction torque is more dominant in the high rotation range.

On the other hand, the rolling friction characteristics of elements and the inner and outer rings of the contact angle is equal to the thrust needle bearing 11 and 12, as shown in FIG. 4, up to a predetermined rotational speed N _1, the friction torque tapered roller bearing 1 Although it is less than T ₀ which is smaller than 2, but becomes larger than the tapered roller bearings 1 and 2 when the number of rotations exceeds a predetermined number N ₁ .

That is, the thrust needle bearings 11, 1
No. 2 has the same contact angle between the needle, which is a rolling element, and the outer ring and inner ring, and does not have a rib portion that causes sliding like a taper roller bearing, so that the friction torque is not particularly increased even at low rotation and high load. Instead, the friction torque is basically determined by the friction torque caused by the rolling of the needle, which is a rolling element. However, since the needle accompanies spin when rolling, it has a larger value than the rolling friction torque of the taper rollers 7 and 8 that does not accompany spin during rolling. Therefore, in FIG. 4, the magnitude relation of the friction torques of the taper roller bearings 1 and 2 and the thrust needle bearings 11 and 12 is reversed at the rotational speed N _{1 at} which the friction torque becomes T ₀ .

Considering now the taper roller bearing 2 and the thrust needle bearing 12 that axially support the output gear 26, as shown in FIG. 3, the thrust load Fa from the output gear 26 side corresponds to the clamping pressure of the power roller 22. When the output gear 26 starts to rotate from the stopped state, the torque that attempts to rotate the inner ring 4 of the tapered roller bearing 2 is the loss torque (friction torque, the same applies hereinafter) T ₁ of the thrust needle bearing 12. . The inner ring and the outer ring of the thrust needle bearing 12 are respectively the output gear 2
The side surface 26b of 6 and the end surface 4b of the inner ring 4 correspond to each other.

Loss torque T ₁ of thrust needle bearing 2
There In smaller than the loss torque T ₂ of the tapered roller bearing 2 (rotational speed N ₁ below the section of FIG. 4), the tapered roller bearing 2 only thrust needle bearing 12 is rotated is not rotated, the thrust load thrust Needle bearing 12
The radial load is supported by the radial needle bearings 16, respectively.

On the other hand, when the rotational speed exceeds the predetermined value N ₁ and the loss torque T ₁ of the thrust needle bearing 12 is larger than the loss torque T ₂ of the taper roller bearing 2, only the taper roller bearing 2 rotates. Thus, the thrust load and the radial load are supported.

Therefore, the overall characteristics of the friction torque of the thrust needle bearing 12 and the taper roller bearing 2 arranged in series are as shown by the solid line in FIG.
In the low rotational speed region below the rotational speed N _{1 where} the loss torque T ₁ of the thrust needle bearing 12 is smaller than the loss torque T ₂ of the taper roller bearing 2, the taper roller bearing 2 stops and only the thrust needle bearing 12 rotates. Loss torque T ₂ of the tapered roller bearing 2 while supporting the thrust load
<Thrust needle bearing 12 supports the thrust load by rotating thrust needle bearing 12 and rotating only taper roller bearing 2 in the rotation range of rotational speed N ₁ or higher where loss torque T ₁ of thrust needle bearing 12 is reached. Although not shown, the same applies to the tapered roller bearing 1 and the thrust needle bearing 11 that support the input shaft 14.

Thus, in the low rotation range of the input / output shaft where the loss torque T ₂ of the tapered roller bearings 1 and ₂ becomes extremely large, only the thrust needle bearings 11 and 12 rotate to support the thrust load, while the thrust needles Bearing 1
At a predetermined rotational speed N ₁ or more where the loss torque T ₂ is smaller than the loss torque T _{1 of} Nos. 1 and 12, only the tapered roller bearings 1 and 2 rotate to selectively support the thrust load. Therefore, it is possible to prevent an extreme increase in the loss torque in the low rotation range as in the conventional example, and it is possible to improve the power transmission efficiency of the continuously variable transmission in the entire rotation range.

FIG. 5 shows a second embodiment, in which the thrust needle bearings 11 and 12 of the first embodiment are replaced with angular ball bearings 110 and 120, respectively, and other configurations are the same as those of the first embodiment. Is the same as.

An inner ring 3a 'and an outer ring 68a' of the angular ball bearing 110 are formed on the inner ring 3 of the tapered roller bearing 1 and the flange portion 68a of the spacer 68, which face each other, and these inner ring 3a 'and outer ring 68a' are formed. Balls 111 having the same contact angle are interposed to support thrust and radial loads. In addition, angular ball bearing 1
By adopting No. 10, the radial needle bearing 15 of the first embodiment is omitted.

Similarly, on the output shaft side, an inner ring 4a 'and an outer ring 26b' of the angular ball bearing 120 are formed on the inner ring 4 of the tapered roller bearing 2 and the output gear 26 which face each other, and these inner ring 4a 'are formed. And outer ring 26b '
A ball 121 having a contact angle equal to that of the angular ball bearing 120 is mounted to support the thrust and the radial load.
Therefore, the radial needle bearing 16 of the first embodiment is omitted.

Also in this case, as in the first embodiment,
Spin occurs when the rolling elements roll, but the loss torque of the angular ball bearings 110, 120 without a collar does not become excessive even in the low rotation range, and only the angular ball bearings 110, 120 rotate in the low rotation range. However, at a predetermined number of revolutions or more at which the magnitude relation of the loss torque is reversed, only the tapered roller bearings 1 and 2 can rotate to support a large thrust load that clamps and presses the power roller 22, and is continuously variable in the entire rotation range. It is possible to improve the power transmission efficiency of the transmission.

[0050]

As described above, according to the first aspect of the invention, in the tapered roller bearing, the friction torque becomes large due to the contact between the flange portion and the rolling element in the low rotation range, but the friction torque increases as the rotation speed increases. Is reduced. On the other hand, since the second bearing does not have a flange with the same contact angle, no slippage occurs at this flange and the friction torque does not become excessive even in the low rotation range. Therefore, in the low rotation range, the friction torque of the second bearing is smaller than that of the taper roller bearing, so that only the second bearing rotates and receives the thrust load. On the other hand, when the number of rotations increases, the sliding friction torque at the flange portion of the friction torque of the taper roller bearing decreases, and the rolling friction torque of the rolling element becomes dominant, the second bearing is originally the rolling element. Since the rolling torque is greater than the friction torque of the tapered roller bearing, in which the rolling element rolls without spin, the friction torque is greater than the friction torque of the tapered roller bearing, so only the tapered roller bearing must rotate to support the thrust load. The tapered roller bearing and the second bearing selectively rotate according to the magnitude of the friction torque, so that the input / output shaft can be smoothly rotated while preventing an extreme increase in the friction torque in the low rotation range. Therefore, the power transmission efficiency of the continuously variable transmission can be improved in the entire rotation range.

The second invention, like the first invention, supports the thrust load applied to the input / output shaft by rotating only the thrust needle bearing in which the friction torque becomes relatively small in the low rotation range. On the other hand, when the number of rotations increases, the friction torque becomes relatively small. Only the tapered roller bearing rotates to support the thrust load and prevent the friction torque from increasing in the low rotation range, while smoothing the input / output shaft. Therefore, the power transmission efficiency of the continuously variable transmission can be improved in the entire rotation range.

The third invention, like the first invention, supports the thrust load applied to the input / output shaft by rotating only the angular ball bearing in which the friction torque becomes relatively small in the low rotation range. On the other hand, when the rotation speed increases, only the tapered roller bearing rotates to support the thrust load, and the input / output shaft can be smoothly supported while preventing the friction torque from increasing in the low rotation range. It is possible to improve the power transmission efficiency of the continuously variable transmission in the entire rotation range.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a toroidal type continuously variable transmission showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a bearing portion of the input / output shaft.

FIG. 3 is an explanatory diagram showing forces applied to a tapered roller bearing and a thrust needle bearing on the output shaft side.

FIG. 4 is a graph showing the relationship between shaft rotation speed and friction torque.

FIG. 5 is an enlarged cross-sectional view of the bearing portion of the input / output shaft according to the second embodiment.

FIG. 6 is a sectional view of a main part of a conventional toroidal type continuously variable transmission.

FIG. 7 is a half sectional view of the tapered roller bearing.

FIG. 8 is a graph showing the relationship between rolling friction torque and sliding friction torque generated in the tapered roller bearing and the number of rotations.

FIG. 9 is a graph showing the relationship between the friction torque generated in the tapered roller bearing and the number of rotations when the thrust load is changed.

[Explanation of symbols]

 1 taper roller bearing 2 taper roller bearing 3, 4 inner ring 5, 6 outer ring 7, 8 taper roller 11, 12 thrust needle bearing 14 input shaft 15, 16 radial needle bearing 18 input disc 20 output disc 22 power roller 26 output gear 26a cylindrical portion 26b Side surface 30, 50 Raceway surface 40, 60 Raceway surface 31, 41 Large brim 67 Casing 68a Cylindrical portion 68b End surface 70 Disc spring 110, 120 Angular ball bearing

Claims (3)

[Claims] 1. An input disk connected to an input shaft, an output disk connected to an output shaft, a power roller sandwiched between toroidal grooves formed on opposing surfaces of the input and output disks, respectively. In a toroidal type continuously variable transmission including an input side bearing means and an output side bearing means for axially supporting an input shaft and an output shaft respectively inside a casing, at least one of the input side bearing means and the output side bearing means. Is a toroidal type continuously variable transmission in which a tapered roller bearing and a second bearing having the same contact angle between the rolling element and the outer ring and the inner ring are arranged in series. 2. The toroidal type continuously variable transmission according to claim 1, wherein the second bearing is a thrust needle bearing. 3. The toroidal type continuously variable transmission according to claim 1, wherein the second bearing is an angular ball bearing.