JPS6165953A - Sealing construction of v-belt type non-stage transmission - Google Patents

Abstract

PURPOSE:To prevent oil from leaking by disposing diaphragms between the end part and the shaft part of a cylinder which surrounds the hydraulic working chamber of a V-belt type non-stage speed change gear. CONSTITUTION:The hydraulic working chamber 19 of a non-stage speed change gear having a V-belt 50 has sub chambers 20 and 21 positioned at the inner diameter side and at the back of said chamber 19. The hydraulic working chamber 19 and the sub chamber 20 placed at the inner diameter side thereof are separated by a primary diaphragm 22 and the hydraulic working chamber 19 and the other sub chamber 21 placed at the back thereof are separated by a fixed and bent piston 23 which is stuck to a driven shaft 11. In addition, the back side sub chamber 21 is separated from the outside by a secondary diaphragm 24. Oil will thereby be prevented from leaking to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a V-belt continuously variable transmission suitable as an automobile transmission, and more particularly to a seal structure for preventing leakage of hydraulic fluid in the continuously variable transmission.

Conventional technology and its problems Conventionally, as described in Japanese Patent Laid-Open No. 58-42862, a movable sheave is moved in the axial direction behind the movable sheave of a driving pulley and a driven pulley around which a V-belt is wound. Continuously variable transmissions are known that are integrally provided with a hydraulic operating chamber for the purpose of By controlling the hydraulic pressure to the hydraulic working chamber, the movable sheave can be moved in the axial direction, and the pulley ratio (speed ratio) between the driving pulley and the driven pulley can be changed steplessly.

By the way, in a continuously variable transmission that uses a metal 1V belt, it is necessary to constantly lubricate the V belt, so there is no problem even if oil leaks from the hydraulic operating chamber.
In continuously variable transmissions that use belts or rubber V-healds, if oil adheres to the V-belt, the frictional resistance between the V-belt and the belt transfer surface will be extremely reduced, making it impossible to obtain the necessary transmission torque. Protect the belt from oil and gear/
It is necessary to completely eliminate oil leakage from the hydraulic working chamber. Therefore, it is conceivable to seal the inside and outside of the hydraulic operating chamber with an oil seal or an O-ring. Since the ring slides against the shaft, an oil film forms on this sliding part and does not create a perfect seal, causing the leaked oil to fly away due to the centrifugal force caused by the rotation of the boob and enter the V-heald. There is a problem that it sticks and stains the engine room.

Purpose of the Invention The present invention has been made in view of such conventional problems.
The purpose is to provide a seal structure for a V-held continuously variable transmission that can completely prevent oil leakage from a hydraulic chamber.

Structure of the Invention In order to achieve the above object, the present invention provides a diaphragm between the end of the cylinder surrounding the hydraulic chamber and the shaft, and seals the inside and outside of the cylinder with this diaphragm. In other words, the diaphragm is an oil seal or
Unlike a ring, it does not have any sliding parts, so it can completely prevent oil leakage from the hydraulic chamber.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example of a continuously variable transmission according to the present invention. This continuously variable transmission includes a driving pulley 1, a driven pulley 10, and an endless belt 50 wound between these pulleys. These boots U1.10 are provided outside the gear case 6 (see FIG. 2).

The drive pulley 1 has a fixed sheave 3 fixed to the drive shaft 2 and a movable sheave 4 that is movable relative to the drive shaft 2. By pressing the movable sheave 4 from behind with the actuating means 5, The pulley diameter is variable. The actuating means 5 includes a hydraulic pulley ratio control means equipped with a hydraulic actuating chamber (to be described later), a centrifugal actuating means that moves the movable sheave 4 in the axial direction by centrifugal force accompanying rotation, and an input torque of the drive shaft 2. There are torque cam means and the like that generate commensurate sheave thrust.

Similarly to the driving side boob I71, the driven side boob 1710 also includes a fixed sheave 12 fixed to the driven shaft 11, a movable sheave 13 that is movable in the axial direction with respect to the driven shaft 11, and a movable sheave 1.
3 in the axial direction.

The configuration of the driven pulley lO will be explained in detail according to Fig. 2.
The fixed sheave 2 is spline-engaged with the end of the driven shaft 11 and coupled with a rotation stopper nut 14. A vertical groove 15 is formed on the inner circumferential surface of the boss portion 13a of the movable sheave 13, and a vertical groove 15 is formed on the outer circumferential surface of the driven shaft 11.
By arranging a plurality of poles I7 between the movable sheave 13 and the driven shaft 11, the movable sheave 13 is movable only in the axial direction. A hydraulic chamber 19 that constitutes a part of the hydraulic pulley ratio control means 18 is integrally provided at the back of the movable sheave 13, and the hydraulic pressure acting on this hydraulic chamber 19 is controlled by a hydraulic control valve (not shown). By this, movable sheave 1
3 in the axial direction, and adjust the boolean ratio between the driving side and the driven side (
transmission ratio) can be changed steplessly. In FIG. 2, the upper half of the driven shaft 11 shows the state in which the pulley diameter of the driven pulley 10 is the smallest, and the lower half shows the state in which the pulley diameter is the largest.

The specific configuration of the hydraulic pulley ratio control means 18 includes, for example, a pitot tube that detects the engine rotation speed, a cam that interlocks with the throttle opening, and a pitot tube, as described in Japanese Patent Application Laid-Open No. 58-42862. It may be configured with a hydraulic control valve that controls the pulley ratio based on the hydraulic signal from the cam and the displacement signal of the cam, or any other hydraulic control method may be used.

By the way, even when the hydraulic pressure to the hydraulic chamber 19 is zero, hydraulic pressure is generated in the hydraulic chamber 19 due to centrifugal force based on the rotation of the driven pulley lO, and this hydraulic pressure moves the movable sheave 13 to change the pulley ratio. may change. In order to eliminate this deviation in the boost ratio, sub-chambers 20 and 21 are provided on the inner diameter side and the rear side of the hydraulic working chamber 19.

The hydraulic working chamber 19 and the inner subchamber 20 are partitioned by a first diaphragm 22, and the hydraulic working chamber 19 and the back subchamber 21 are partitioned by a bent fixed piston 23 fixed to the driven shaft 11. The collateral chamber 21 and the outside are separated by a second diaphragm 24. That is, the inner and outer peripheral parts of the first diaphragm 22 are closely fixed to the boss part 23a of the fixed piston 23 and the annular wall 13b protruding from the back surface of the movable sheave 13, while the inner and outer peripheral parts of the second diaphragm 24 are , is closely fixed to a sleeve 25 (shaft portion) fitted onto the driven shaft 11 and an end of a cylinder 26 connected to the movable sheave 13. Therefore, the spaces between the hydraulic chamber 19 and the inner sub-chamber 20 and between the back sub-chamber 21 and the outside are completely sealed, and no oil can escape.

Note that the fixed piston 23 has a bent shape, and the first
The reason why the diaphragm 22 is arranged on the outer diameter side of the second diaphragm 24 is to shorten the space in the axial direction. That is, the pulley diameter of the driven pulley 10 is the minimum (second
When the outer circumference of the first diaphragm 22 is in the outer diameter recess 23b of the fixed piston 23 (upper half of the figure), and when the pulley diameter of the driven pulley 10 is at its maximum (lower half of the figure 2), the second diaphragm 24 is The outer periphery is a fixed piston 23
It fits into the inner diameter side recess 23C. Therefore, the outer peripheries of the first and second diaphragms 22 and 24 can be displaced to positions close to each other depending on whether the pulley diameter is the minimum or the maximum, and the axial direction is proportional to the stroke of the movable sheave 13. Space can be shortened.

As mentioned above, working pressure is applied to the hydraulic working chamber 19 from the hydraulic control valve through the oil passage 27, and low-pressure lubrication is applied to the unidirectional radial subchamber 20 from the oil pump 28 through the orifice 29. A lubrication oil passage 30 for supplying oil communicates with the sub-chambers 20, 21, and a communication passage 3 provided in the fixed piston 23.
It communicates via 1. In other words, the first diaphragm 2
Only the difference between the hydraulic pressure in the hydraulic chamber 19 and the centrifugal force in the auxiliary chamber 20 acts on the second diaphragm 24, while only a small hydraulic pressure due to the centrifugal force acts on the second diaphragm 24. There is no excessive load. Therefore, even a diaphragm that is generally considered to have poor pressure resistance can be made sufficiently durable for practical use.

Here, the sub-chamber 20. The operation of '21 will be explained with reference to FIG. Now, while the driven pulley 10 is rotating, in addition to the operating pressure, a hydraulic pressure corresponding to the centrifugal force is generated in the hydraulic chamber 19, and this hydraulic pressure causes the movable sheave 13 to move the fixed sheave 12011 ( (towards the left in Figure 3). On the other hand, the auxiliary chamber 2 rotates integrally with the hydraulic working chamber 19.
0 and 21 are also generated due to centrifugal force, and due to this oil pressure, the inner subchamber 20 pushes the movable sheave 13 to the left in FIG.
Push it to the right in Figure 3 with the force of . At this time, the hydraulic working chamber 19
Since the sum of the areas of the hydraulic working surface of the inner diameter subchamber 20 and the hydraulic working surface of the inner subchamber 20 is set approximately equal to the hydraulic working area of the rear subchamber 21, the hydraulic pressure due to the centrifugal force is balanced on the left and right sides, and the pulley ratio is I never go crazy.

In the above embodiment, the auxiliary chambers 20.2 are located on both sides of the hydraulic working chamber 19.
1 is provided, but the purpose of the auxiliary chamber 20 is to eliminate the imbalance between the hydraulic working surface of the hydraulic working chamber 19 and the hydraulic working surface of the auxiliary chamber 21. If the areas of the surfaces are set to be approximately equal, the subchamber 20 is not necessary.

Further, in the above embodiment, there is no seal between the inner diameter side subchamber 20 and the outside by a diaphragm, but since this subchamber 20 is located on the smaller diameter side than the rear side subchamber 21, the hydraulic pressure due to centrifugal force is low. This is because the oil seal 32 provided at the tip of the boss portion 13a of the movable sheave 13 can also sufficiently prevent oil leakage.

In addition, although the hydraulic operating chamber I9 and the auxiliary chamber 20 are partitioned by the first diaphragm 22, a complete seal between the compartments 19 and 20 is not necessarily required, so instead of the first diaphragm 22, a normal oil seal or a A ring may also be used.

Effects of the Invention As is clear from the above description, according to the present invention, since a diaphragm is provided between the cylinder surrounding the hydraulic working chamber and the shaft, oil leakage to the outside can be completely prevented. Also,
Since the cylinder and the shaft do not slide relative to each other, the movement of the movable sheave is extremely smooth, and since dimensional accuracy between the cylinder end and the shaft is not required, manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a heald-type continuously variable transmission according to the present invention, FIG. 2 is a detailed sectional view of the driven pulley, and FIG. 3 is a schematic diagram showing the function of the auxiliary chamber. ■... Drive side pulley, 10... Driven side pulley, 13
...Movable sheave, 19...Hydraulic operating chamber, 20.21
...Antechamber, 22. '24...Diaphragm, 23.
...Fixed piston, 26...Cylinder, 50...■
belt.

Claims (1)

[Claims] (1) In a V-belt continuously variable transmission in which a hydraulic chamber for moving the movable sheave in the axial direction is integrally provided in at least one movable sheave of the driving pulley or the driven pulley, the hydraulic chamber A seal structure for a V-belt continuously variable transmission, characterized in that a diaphragm is provided between an end of a cylinder surrounding the cylinder and a shaft.