JP3223367B2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission.

[0002]

2. Description of the Related Art Conventionally, in a continuously variable transmission, a V-groove is formed by a fixed pulley fixed to a shaft and a movable pulley which can be separated from and connected to the fixed pulley, and a belt is applied to the V-groove. Conventionally, torque is uniformly applied to the fixed pulley and the movable pulley from the belt, and the movable pulley is configured to be slidable in the axial direction via the ball spline with respect to the shaft. There is a problem in that torque is applied and the ball spline must be made of an expensive and durable material.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a continuously variable transmission that can use an inexpensive ball spline. The gist is that the drive pulley provided on the drive shaft and the driven pulley provided on the driven shaft are each composed of a fixed pulley fixed to the shaft and a movable pulley detachable from the fixed pulley. Is
The rotation direction is regulated via a ball spline and disposed so as to be movable in the axial direction.A belt is mounted between the drive pulley and the driven pulley, and the rotation of the drive shaft is steplessly shifted to thereby allow the driven shaft to rotate. In the continuously variable transmission transmitted to the shaft, a friction coefficient of a contact portion between the movable pulley and the belt is set to be lower than a friction coefficient of a contact portion between the fixed pulley and the belt. It is.

[0004]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of the continuously variable transmission, in which a drive shaft 2 of the continuously variable transmission 1 is provided with a drive pulley 3, and the drive pulley 3 is a fixed pulley fixed to the drive shaft 2. 4 and a movable pulley 5 that moves axially on the drive shaft 2 via a ball spline 11 so as to be able to separate from and contact with the fixed pulley 4. A driven shaft 6 is parallel to the drive shaft 2. The driven shaft 6 is also provided with a driven pulley 7, and the driven pulley 7 is
And a movable pulley 9 which can be separated from and connected to the fixed pulley 8 and slides on a driven shaft 6 via a ball spline 11. The driving pulley 3 and the driven pulley 7 A belt 10 is mounted between the belts so that the rotation of the drive shaft 2 is continuously variable and transmitted to the driven shaft 6. In FIG. 1, reference numeral 12 denotes an intermediate shaft provided in parallel with the driven shaft 6, and reference numeral 13 denotes a differential gear. FIG. 2 is an enlarged view around the driven shaft 6 in FIG.

The movable pulley 5 constituting the driving pulley 3 and the movable pulley 9 constituting the driven pulley 7 are each configured to be slidable in the axial direction with the rotation direction thereof being regulated by a ball spline 11. When hydraulic pressure is supplied to a hydraulic chamber P formed on the back side of each of the movable pulleys 5 and 9, the hydraulic pulleys 5 can move in the axial direction, and the balls 14 provided in the ball spline 11 roll and satisfactorily move. 9 can move in the axial direction,
If the torque transmitted via the belt 10 is uniformly applied to, for example, the fixed pulley 8 and the movable pulley 9 of the driven pulley 7, the life of the ball spline 11 is reduced by the torque. The coefficient of friction of the contact portion b of 10 is set in advance so as to be lower than the coefficient of friction of the contact portion a between the fixed pulley 8 and the belt 10.

That is, the surface roughness of the contact surface of the movable pulley 9 is made finer than that of the contact surface of the fixed pulley 8, so that the friction coefficient on the movable pulley 9 side can be set to be low. A large amount of torque is transmitted from the fixed pulley 8 side to the driven shaft 6 and a small torque is transmitted from the movable pulley 9 to the driven shaft 6. For example, the friction coefficient of the contact surface of the movable pulley 9 is If the friction coefficient of the contact surface is about two-thirds, the torque applied to the ball spline 11 from the movable pulley 9 will be reduced as compared with the conventional art, whereby the torque transmitted to the ball spline 11 will be reduced. Is also lower,
The durability of the ball spline 11 is improved,
Even if the ball spline 11 which is cheaper than the conventional one is adopted, sufficient durability can be obtained.

When the friction coefficient of the contact surface between the pulley and the belt is set, the friction coefficient of the contact surface on the belt side may be changed. In this case, the driven side to which a large torque is applied is prioritized, and The friction coefficient of the contact surface of the belt 10 that contacts the pulley 9 can be set to be lower than the friction coefficient of the contact surface that contacts the fixed pulley 8.

[0008]

According to the present invention, the driving pulley provided on the driving shaft and the driven pulley provided on the driven shaft are each composed of a fixed pulley fixed to the shaft and a movable pulley detachable from the fixed pulley. The movable pulley is arranged so as to be movable in the axial direction with the rotation direction regulated via a ball spline, and a belt is mounted between the drive pulley and the driven pulley to rotate the drive shaft. In the continuously variable transmission in which the speed is continuously changed and transmitted to the driven shaft, a friction coefficient of a contact portion between the movable pulley and the belt is lower than a friction coefficient of a contact portion between the fixed pulley and the belt. Is set so that the torque transmitted from the belt to the movable pulley is lower than the torque transmitted from the belt to the fixed pulley. Since the torque transmitted to the emission can be reduced than conventionally, having the effect of sufficient durability can be obtained by using an inexpensive ball spline.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a continuously variable transmission.

FIG. 2 is an enlarged configuration diagram of a main part of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 continuously variable transmission 2 drive shaft 3 drive pulley 4 fixed pulley 5 movable pulley 6 driven shaft 7 driven pulley 8 fixed pulley 9 movable pulley 10 belt 11 ball spline 14 ball P hydraulic chamber a belt contact portion between fixed belt and fixed pulley b belt Of contact between the pulley and the movable pulley

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-288452 (JP, A) JP-A-63-297850 (JP, A) JP-A-10-2381 (JP, A) 59559 (JP, U) JP-A-5-14719 (JP, U) JP-B-60-44533 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 9/00-9 / 26 F16H 55/32-55/56 F16G 5/16

Claims (1)

(57) [Claims] 1. A drive pulley provided on a drive shaft and a driven pulley provided on a driven shaft each include a fixed pulley fixed to the shaft, and a movable pulley detachable from and attached to the fixed pulley. The movable pulley is disposed so as to be movable in the axial direction with the rotation direction regulated via a ball spline, and a belt is mounted between the driving pulley and the driven pulley, so that the rotation of the driving shaft is continuously variable. In the continuously variable transmission that is transmitted to the driven shaft, the friction coefficient of a contact portion between the movable pulley and the belt is
A continuously variable transmission, wherein the transmission is set to be lower than a friction coefficient of a contact portion between the fixed pulley and the belt.