JP2007239911A - V-belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a V-belt type continuously variable transmission preventing the loosening of a bearing rotatably supporting a drive shaft. <P>SOLUTION: The V-belt type continuously variable transmission is comprised of a drive pulley 16 and a driven pulley 26 provided with pairs of fast pulleys 18, 30, respectively, and movable pulleys 22, 34, and a V-belt 1 suspended between the drive pulley and the driven pulley. Bearings 88a, 88b are provided for rotatably supporting both ends of the drive shaft 14 transmitting rotation from a drive source to the fast pulley, and a portion for press-fitting the bearing of the drive shaft is tapered so that a diameter becomes smaller as it is separated from the fast pulley 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a V-belt type continuously variable transmission.

In conventional V-belt type continuously variable transmissions, as a means for restricting the axial position of the fixed pulley that constitutes the drive pulley, the position of the support bearing of the drive shaft that is integrally formed with the fixed pulley is restricted to the casing by a snap ring. There is a means to do this (see Patent Document 1, especially FIG. 2). Further, there is a means for eliminating the snap ring for cost reduction and providing a wall for restricting the axial position of the bearing on the casing itself.
JP 7-243500 A

  However, if a wall for position regulation is provided in the casing, the position of this wall is prioritized, and the design freedom of the casing is narrowed. Further, when the positioning wall is abolished, the drive shaft is deformed by an input generated at the time of shifting, and the deformation may cause the bearing to come out of the drive shaft. The mechanism by which the bearing comes out will be described later.

  The present invention has been made in view of these facts, and an object of the present invention is to provide a V-belt continuously variable transmission that prevents a bearing from coming out of a drive shaft when the drive shaft is deformed.

  The present invention relates to a V-belt continuously variable transmission comprising a drive pulley and a driven pulley each having a pair of fixed pulleys and a movable pulley, and a V-belt stretched between the drive pulley and the driven pulley. A bearing that rotatably supports both ends of the drive shaft that transmits rotation from the fixed pulley is provided, and the portion of the drive shaft into which the bearing is press-fitted is tapered so as to become smaller in diameter as the distance from the fixed pulley increases. The V-belt type continuously variable transmission is characterized in that it is formed as follows.

  The present invention can prevent the bearing from coming out of the drive shaft by bringing the drive shaft and the bearing into surface contact even when the drive shaft is deformed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the configuration of a V-belt type continuously variable transmission. This continuously variable transmission includes a torque converter (starting mechanism) 12, a forward / reverse switching mechanism 15, a V-belt continuously variable transmission mechanism 29, and an operating device 56, and rotates the output shaft 10 of the engine with a predetermined gear ratio and rotation. Direction to the actuator 56.

  The torque converter 12 includes a so-called lockup mechanism, and controls the hydraulic pressure of the lockup oil chamber 12a to mechanically connect or disconnect the input-side pump impeller 12b and the output-side turbine liner 12c. Has been. The output shaft of the torque converter 12 is connected to a rotating shaft (input shaft) 13, and the rotating shaft 13 is connected to a forward / reverse switching mechanism 15.

  The forward / reverse switching device 15 includes a pair of planetary gear devices 19, a forward clutch 40, and a reverse brake 50, and is a known forward / reverse switching mechanism that switches the rotational direction of the engine output shaft 10 in accordance with the traveling direction of the vehicle. It is.

  The V-belt type continuously variable transmission mechanism 29 includes a drive pulley 16, a driven pulley 26, and a V-belt 24 that is coupled between the drive pulley 16 and the driven pulley 26 so as to be able to transmit power. Both ends of the drive shaft (output shaft) 14 are rotatably supported by the casing 83 by bearings 88 a and 88 b, and the drive pulley 16 is provided coaxially with the drive shaft 14. The fixed pulley 18 rotates integrally with the drive shaft 14. A movable pulley 22 is provided which is disposed to face the fixed pulley 18 to form a V-shaped pulley groove and which can be moved in the axial direction of the drive shaft 14 by hydraulic pressure acting on the drive pulley cylinder chamber 20.

  The driven pulley 26 is provided coaxially with a driven shaft 28 that is parallel to the drive shaft 14 and the central axis. The driven pulley 26 rotates in unison with the driven shaft 28, and is disposed opposite to the fixed pulley 30. And a movable pulley 34 that forms a letter-shaped pulley groove and is movable in the axial direction of the driven shaft 28 by hydraulic pressure acting on the driven pulley cylinder chamber 32. A V-belt continuously variable transmission mechanism 29 is configured by connecting the V-belt 24 to the pulley grooves of the driving pulley 16 and the driven pulley 26 so as to be able to transmit.

  In the operating device 56, the drive gear 46 rotates integrally with the driven shaft 28, the idler gear 48 meshes with the drive gear 46 that rotates integrally with the idler shaft 52, and the pinion gear 54 rotates integrally with the idler shaft 52. The pinion gear 54 and the final gear 44 mesh with each other.

  FIG. 2 is a view for explaining the withdrawal of the bearing, which is the subject of the present invention. First, a mechanism in which the output shaft 14 is deformed and the bearing 88a is removed from the drive shaft 14 will be described.

  When the tension of the belt 24 acts on the upper portion (belt pull-in side) of the drive pulley 16 at the time of shifting, a moment M is generated to expand the pulley groove formed by the fixed pulley 18 and the movable pulley 22 of the drive pulley 16. This moment M acts on the bearing 88a in the same way via the fixed pulley 18, and becomes a force F that pulls the bearing 88a out of the drive shaft 14.

  Further, while preventing slippage between the belt 24 and the sheave surfaces of the pulleys 18 and 22, pulley thrust for transmitting power also acts on the bearing 88a via the fixed pulley 18, and this force also acts on the bearing 88a as a drive shaft. 14 influences force F to escape from 14.

  When the belt tension and the pulley thrust act, the drive shaft 14 is deformed into a convex shape centered between the two pulleys and opposite to the direction of the belt tension (shown by a broken line in FIG. 2).

  Further, as a phenomenon that promotes the withdrawal of the bearing 88a, there is a change in the contact form between the bearing 88a and the drive shaft 14. That is, in the normal state, the bearing 88a and the drive shaft 14 are in contact with each other by surface contact, but the output shaft 17 is deformed by the belt tension and the pulley thrust, whereby the belt tension of the bearing 88a is loaded ( The contact form changes to line contact on the side indicated in detail in FIG. By changing the contact form from the surface contact to the line contact, the force that suppresses the pull-out due to the fitting between the bearing 88a and the drive shaft 14 is reduced, and the pull-out is facilitated.

  Therefore, conventionally, in order to suppress the pull-out force F, for example, a snap ring for the drive shaft 14 and the bearing 88a is arranged, so that the cost increases due to an increase in the number of parts and processing of a groove for fitting the snap ring. I was invited.

  The present invention pays attention to the fact that the contact of the bearing 88a can be suppressed by suppressing the change of the contact form between the bearing 88a and the drive shaft 14 and maintaining the surface contact, and the method will be described below.

  As a basic idea, the deflection of the drive shaft 14 is anticipated in advance so that the drive shaft 14 and the inner diameter portion of the bearing 88a are in surface contact with each other on the side where the belt tension is applied when the drive shaft is deformed. The shaft diameter of the portion into which the bearing 88a is press-fitted is set.

  Hereinafter, the present invention will be described with reference to FIG. As described above, the drive shaft 14 is deformed by the input, and the contact between the drive shaft 14 and the bearing 88a becomes a line contact (see the left diagram in FIG. 3). For this reason, in the present invention, the shaft diameter of the bearing 88a press-fitting portion of the drive shaft 14 is formed in a tapered shape so as to become smaller as the distance from the fixed pulley 18 (the shaft diameter gradually decreases) (in FIG. 3). (Refer to the broken line shape on the right). With such a tapered shape, as indicated by the alternate long and short dash line in the right diagram of FIG. 3, even after the drive shaft 14 is deformed, the drive shaft 14 and the bearing 88 a are in surface contact, and the bearing 88 a is separated from the drive shaft 14. It becomes difficult to escape. At this time, the diameter is set so as to prevent the bearing 88a from slipping out at the time of maximum deformation of the drive shaft 14. However, the backlash of the bearing 88a during normal operation does not occur. Needless to say, Specifically, by changing the shaft diameter from 0.005 ° to 0.018 ° as the taper angle, it is possible to prevent the bearing 88a from slipping out at the time of shifting without affecting the other.

  Therefore, in the present invention, in the V-belt type continuously variable transmission, bearings that rotatably support both ends of the drive shaft that transmits the rotation from the drive source to the fixed pulley are provided, and the bearing of the drive shaft is press-fitted. Since the shaft diameter is formed so as to be smaller as it is farther from the fixed pulley, the drive shaft can be brought into surface contact with the bearing even when the drive shaft is deformed, and driving without using a snap ring or the like is possible. The bearing can be prevented from coming off from the shaft.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

It is sectional drawing of the V belt type continuously variable transmission of this embodiment. It is a figure explaining the deformation | transformation of a drive shaft, and the withdrawal of a bearing. It is a figure explaining the shape of the drive shaft of this embodiment.

Explanation of symbols

13 Rotating shaft (input shaft)
14 Drive shaft (output shaft)
16 Driving pulley 18 Fixed pulley 19 Planetary gear device 22 Movable pulley 24 V belt 26 Driven pulley 83 Casing 88a Bearing

Claims (4)

A driving pulley and a driven pulley each comprising a pair of fixed pulley and movable pulley;
In a V-belt type continuously variable transmission comprising a V-belt suspended between these drive pulley and driven pulley,
A bearing that rotatably supports both ends of the drive shaft that transmits the rotation of the drive source to the fixed pulley is provided,
The V-belt continuously variable transmission is characterized in that a portion of the drive shaft into which the bearing is press-fitted is tapered so as to have a smaller diameter as the distance from the fixed pulley increases.   The shaft diameter of the drive shaft is set according to the deformation of the press-fitting portion of the drive shaft by the tension of the V-belt and the thrust that presses the V-belt of the movable pulley against the fixed pulley. Item 2. The V-belt type continuously variable transmission according to item 1.   The shaft diameter is such that the press-fitted portion of the drive shaft and the bearing are in surface contact with each other when the press-fitted portion of the drive shaft is deformed by the tension of the V-belt and the thrust that presses the V-belt of the movable pulley against the fixed pulley. The V-belt continuously variable transmission according to claim 2, wherein the V-belt continuously variable transmission is set.   2. The V-belt continuously variable transmission according to claim 1, wherein a taper angle of a portion of the drive shaft into which the bearing is press-fitted is 0.005 ° to 0.018 °.

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