JP3155609B2 - Accumulator for hydraulic control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator used for a hydraulic control circuit of an automatic transmission for an automobile or the like.

[0002]

2. Description of the Related Art In an automatic transmission, a hydraulic clutch that rotates for switching gears is used. An accumulator is arranged in the middle of the oil passage to the clutch drum to alleviate the sudden change in the hydraulic pressure, and the accumulator is provided with a bleed mechanism for discharging the air in the working pressure chamber to the atmosphere release side when the hydraulic pressure rises excessively. Such a bleed mechanism is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-308257.
For example, a check valve as disclosed in Japanese Unexamined Patent Application Publication No. H10-260, can be used. This is shown in FIG.
Is installed separately in the piston 2 of the accumulator 1, a check ball 8 is disposed in a valve cylinder 5 having a through hole 6 between both ends, and a stop pin 7 is provided across the through hole 6 to provide a check valve unit. Is configured.

[0003]

However, in the above-mentioned conventional accumulator, high fitting accuracy is required for a fitting portion in which the check valve 4 as a unit is incorporated into the piston 2, so that the cost and the number of steps of the assembling work are reduced. There is such a problem, and there is also a possibility that parts such as the retaining pin 7 may be missing at the time of assembly. In addition, considerable attention must be paid to ensuring the sealing performance of the fitting as a basic function. In addition, a through hole 9 for passing the retaining pin 7 must be provided in the valve cylinder 5, which also increases the number of working steps, cost, and sealing performance. Moreover, even if the above points are taken into consideration, concerns such as falling off from the fitting portion due to thermal expansion due to temperature change of the hydraulic oil and thermal deformation of a relatively thin valve cylinder are not solved. Accordingly, an object of the present invention is to provide an accumulator for a hydraulic control circuit that reduces the number of steps and costs when a check valve is provided and does not cause a problem of sealing performance.

[0004]

For this purpose, the present invention comprises a variable-volume working pressure chamber formed by a main body cylinder and a top wall of a piston urged by an accumulator spring and sliding in the main body cylinder, In an accumulator for a hydraulic control circuit for mitigating a change in hydraulic pressure applied to a working pressure chamber, the accumulator for a hydraulic control circuit includes a check valve that allows a limited air flow between the working pressure chamber and the atmosphere side. A valve cylinder for accommodating the check ball, wherein the valve cylinder is formed integrally with the top wall, and the check ball is prevented from coming off by a spring stopper provided between an inner surface of the top wall and an accumulator spring. And

[0005]

Since the valve cylinder of the check valve is formed integrally with the top wall of the piston, it does not require machining accuracy and requires less man-hours than those which are incorporated separately. Of course, there is no problem of the sealing property. A spring stopper provided between the top wall and the accumulator spring prevents the check ball from coming off. The pressing force of the accumulator spring is leveled and evenly applied to the piston top wall over the entire surface of the spring stopper, so that no local load is applied to the inner surface of the top wall.

[0006]

FIG. 1 shows an embodiment of the present invention. A piston 12 is slidably provided in a main body cylinder 11 of the accumulator 10, and the piston 12 is attached to the accumulator spring 1.
5, the volume of the accumulator working pressure chamber R is changed by the hydraulic pressure guided thereto. The piston 12 is formed of a resin material, and a valve cylinder 22 of a check valve 20 is integrally formed on a top wall 13 facing the working pressure chamber R toward the outside of the piston. The valve cylinder 22 has a small-diameter hole 24 at its outer end and a large-diameter hole 2 at its inner side.
6 are provided and are connected by a tapered hole 25 to form a check passage passing through the top wall 13. The inside of the piston communicates with the atmosphere through a passage 17.

[0007] Accumulator spring 15 and top wall 1
A spring stopper 30 is disposed between the spring stopper 30 and the inner surface of the spring 3, and a hole 32 concentric with the check passage is provided in the center of the spring stopper 30. Large diameter hole 26
A check ball 40 having a diameter larger than the diameter of the small-diameter hole 24 is freely movably arranged in a room formed by the tapered hole 25. The diameter of the spring stopper hole 32 is smaller than the diameter of the check ball 40.
0 is prevented from falling off by the spring stopper 30. The spring stopper 30 is always pressed against the inner surface 13a of the top wall 13 by the accumulator spring 15.

As a result, the check ball 40 comes into contact with and separates from the tapered hole 25 on the one hand, and opens and closes the hole 32 of the spring stopper 30 on the other hand. Thus, when the piston 12 slides according to the pressure of the working pressure chamber R between the piston top wall 13 and the cylinder 11, limited air flow is allowed during the movement of the check ball 40 in the valve cylinder 22, The air bleed function is exhibited.

According to the above configuration, the valve cylinder 22
However, since it is integrated with the piston 12, machining and assembling work of the valve cylinder fitting portion become unnecessary, and the problem of sealing performance does not occur. Further, since the check ball 40 is prevented from coming off by the spring stopper 30 receiving the accumulator spring 15, there is no need to provide a special check ball coming off. Even if the piston 12 is formed of a resin material, the pressing force of the accumulator spring 15 is leveled by the spring stopper 30 and is evenly applied to the piston top wall 13 over the entire surface of the spring stopper. There is no possibility that the side surface 13a is locally damaged. Since the spring stopper 30 has a simple washer shape, it can be formed of metal or other resin having high wear resistance.

[0010]

As described above, according to the present invention, the valve cylinder of the check valve provided on the accumulator is formed integrally with the top wall of the piston. Therefore, there is no need to worry about the processing accuracy of the fitting portion without causing the problem of the sealing property of the fitting portion. Further, since a spring stopper is provided between the top wall and the accumulator spring to prevent the check ball from coming off, it is not necessary to perform a special process for preventing the check ball from coming off. As a result, the cost is reduced. In addition, since the pressing force of the accumulator spring 15 is prevented from being locally applied to the top wall by the spring stopper, there is no possibility that the contact portion with the accumulator spring is damaged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Accumulator 2 Piston 4 Check valve 5 Valve cylinder 6 Through hole 7 Stop pin 8 Check ball 10 Accumulator 11 Main body cylinder 12 Piston 12 13 Top wall 15 Accumulator spring 17 Passage 20 Check valve 22 Valve cylinder 24 Small diameter hole 25 Tapered hole 26 Large diameter Hole 30 Spring stopper 32 Hole 40 Check ball R Working pressure chamber

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-308257 (JP, A) JP-A-2-278001 (JP, A) JP-A-61-48601 (JP, A) Jpn. 102603 (JP, U) JP-A 3-17303 (JP, U) JP-A 62-39029 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-63 / 48 F15B 1/00-1/06

Claims (3)

(57) [Claims] A variable-pressure operating pressure chamber formed by a main body cylinder and a top wall of a piston which is urged by an accumulator spring and slides in the main body cylinder, wherein a change in hydraulic pressure received by the operating pressure chamber is detected. In an accumulator for a hydraulic control circuit to be relaxed, the accumulator for a hydraulic control circuit includes a check valve for enabling a limited air flow between the working pressure chamber and the atmosphere side, the check valve including a check ball and a valve cylinder accommodating the check ball. The valve cylinder is formed integrally with the top wall, and the check ball is prevented from coming off by a spring stopper provided between an inner surface of the top wall and an accumulator spring. Accumulator for circuit. 2. The accumulator for a hydraulic control circuit according to claim 1, wherein said spring stopper has a hole having a diameter smaller than that of said check ball at a central portion thereof. 3. The accumulator for a hydraulic control circuit according to claim 1, wherein the top wall is formed of a resin material.