JPS62209201A - Accumulator - Google Patents

Abstract

PURPOSE:To prevent release of a spring fixed to a piston, by fitting a swelled diameter part formed on a spring fixing side, in the large diameter part of the spring fixing part on the piston end face. CONSTITUTION:A depressed spring fixing part 2 is formed on the piston 1 end face of an accumulator A, and the inner surface of the spring fixing part 2 is formed into a taper face 2c, small diameter part 2a, and large diameter part 2b sequentially from its opening side. On the other hand, a swelled diameter part 3a is formed on the side of the spring fixing part 2 for a spring 3 fixed to the spring fixing part 2. With this arrangement, if the swelled diameter part 3a of the spring 3 is fitted in the large diameter part 2b of the spring fixing part 2, the movement of the swelled diameter path part 3a is controlled by means of the small diameter part 2c, thereby the release of the spring 3 can be prevent.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an accumulator in an automatic transmission mounted on an automobile, and more particularly to a fixing structure between a piston and a spring in the accumulator.

(B) Conventional technology Generally, an automatic transmission has a planetary speed change gear mechanism, and predetermined elements of the speed change gear mechanism are engaged or locked by a clutch or a brake (II friction element). It is configured to obtain a desired gear position. These clutches or brakes are controlled by a hydraulic servo to which hydraulic pressure is supplied or drained by switching the shift valve, and an accumulator is installed in parallel to the hydraulic servo.
Based on the hydraulic characteristics of the accumulator, the servo pressure of the hydraulic servo and the engagement characteristics of each clutch and brake are determined.

In addition, for a predetermined accumulator, for example, an accumulator for a second brake that operates in 2nd gear, a disc spring or a piston stroke is disposed on the accumulator chamber side, and the disc spring or spring acts only on the piston stroke start portion. Therefore, it is desirable to configure the accumulator so as to obtain predetermined accumulator characteristics (for example, see Japanese Utility Model Application Publication No. 58-146101). In this case, if a disc spring is used, the degree of freedom in its stroke, load capacity, and elastic modulus is small, and it is extremely difficult to set the desired hydraulic characteristics.In addition, a coil spring is used to fix the spring to the housing side. As a result, the spring tends to tilt, and if the piston comes into contact with the spring in the tilted state, the piston will not be able to move to the lower end of its stroke, which may cause a large shift shock.

→ Problem to be solved by the invention Therefore, the present applicant has developed a method for tightening screws by caulking, tightening bolts, or springs.・An accumulator has been proposed in which a spring is fixed in the spring, thereby preventing the spring from tilting and improving ease of assembly (Japanese Patent Application No. 59-16805).
No. 8 unpublished).

Incidentally, in recent years, automatic transmissions have been used even in small-horsepower automobiles, and automatic transmissions themselves have been required to be smaller due to the shift to F-F (front engine, front drive), etc., and along with this, accumulators have also become smaller. something is required.

In such devices, it is extremely difficult to fix the spring by caulking or bolts, etc., as the inner diameter of the spring is small, and the spring tends to tilt during fixation. Press-fitting using a spring tightening margin makes it easy for the spring to come off and prevents it from coming off (if the tightening margin is increased, it becomes difficult to press-fit the spring).

Furthermore, with the above-described fixing means such as caulking, bolts, press-fitting, etc., the fixed portion is relatively large, and it is necessary to form a large recess in the piston so that the fixed portion does not interfere with the housing. Then, in an accumulator that is normally used with the piston facing upward, air accumulates in the above-mentioned piston recess located at the upper part of the accumulator chamber, and the air pocket formed by the recess occupies a relatively large volume with respect to the accumulator chamber, which affects the accumulator characteristics. deviates from the desired characteristics and changes significantly, causing shift rays to occur.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an accumulator that solves the above-mentioned problems by allowing a spring to be easily and reliably fixed to a piston in a small space.

(Example) Means for Solving the Problem The present invention was developed in view of the above circumstances, and as shown in FIGS. 1 and 2, a small diameter portion 2a is provided on the end surface 1a of the piston 1. A concave spring fixing portion 2 is formed, with the rear side becoming a large-diameter portion 2b.

Further, an expanded diameter portion 3a having a larger diameter than the small diameter portion 2a of the spring fixing portion 2 is formed at one end of the spring 3. The spring 3 is fixed to the piston 1 by fitting the expanded diameter part 3a into the large diameter part 2b. It is preferable to apply this method to a spring 3 having a natural length of 100 mm, which acts at the stroke start portion of the piston 1 in opposition to another spring 6 contracted at the other end of the piston.

(e) Operation Based on the hypothetical configuration, pressure oil is supplied to the accumulator chamber 5 of the accumulator A via the oil passage 7 when pressure oil is supplied to a predetermined engagement element based on the switching circle of the shift valve. Then, the retaining characteristics of the predetermined engagement element are adjusted by the hydraulic pressure acting on the back pressure side spring 6, the back pressure chamber 9, the capacity of the accumulator chamber 5, the predetermined accumulator characteristics based on the spring 3, etc., and the engagement element is smoothly engage.

Similarly, when the predetermined engagement element is released, the pressure oil in the accumulator chamber 5 is drained from the oil passage 7, and the spring 3 contacts the valve body 10 at the lower end of the stroke of the piston 1, and the predetermined engagement is performed based on the accumulator characteristics. Adjust the release of elements.

Further, when assembling, for example, the spring 3 can be easily attached to the end surface of the piston 1 by tilting the spring 3 and pushing it in the direction of the arrow based on the tapered surface 2C of the spring fixing part 2, as shown in FIG. It will be done.

Further, even if air accumulates in the accumulator chamber 5 due to use, the concave portion, which is the spring fixing portion 2, which serves as the air reservoir, is relatively small and does not have a large effect on the accumulator characteristics.

(F) Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

As shown in FIG. 1, the second brake accumulator A has a housing 11 forming a cylinder chamber 11a, and the housing 11 is attached to the valve body 10 by appropriate means.

Further, in the cylinder chamber 11a, a screw 1-1 is connected to an O-ring 1.
2 and 13, and are slidably fitted in an oil-tight manner, and an accumulator chamber 5 is formed between the end surface 1a of the piston and the valve body 10, and both O-rings 12,
13 and the housing 11 constitutes a back pressure chamber 9. Further, an oil passage 7 is communicated with the accumulator chamber 5 through an orifice 15, and the oil passage 7
is in communication with the shift valve and the engagement element (second brake), and the back pressure chamber 9 is in communication with an oil passage 16 extending from the accumulator control valve. Furthermore, a spring 6 is compressed between the other end of the piston 1 and the bottom surface of the housing 11, and the spring 6 always urges the piston 1 toward the accumulator chamber 5. Note that the hole 17 formed in the bottom surface of the housing is an air communication hole.

As shown in detail in FIG. 4, a concave spring fixing part 2 is formed on the end face 1a of the piston l, and the spring fixing part 2 has a tapered surface 2c whose diameter gradually becomes smaller from the end face 1a. It consists of a small diameter portion 2a and a large diameter portion 2b that widens at the back side of the small diameter portion 2c. Further, the spring 3 fixed to the fixing part 2 is made of a coil spring whose natural length is shorter than the piston stroke, and has an expanded diameter part 3a whose one end is expanded in diameter. Then, the diameters of the small diameter part 2a and the large diameter part 2b of the fixed part 2 are set to B and C, respectively.
If the normal diameter of the spring 3 and the diameter of the expanded diameter portion 3a are respectively E, then the relationship is set as follows: D<B<E<C.

Then, as shown in FIG. 3, the spring 3
Taper surface 2 such that a part of a enters fixed part large diameter part 2b.
It is placed obliquely along C, and in this state it is pressed from the direction of the arrow or by slightly twisting, so that the enlarged diameter part 3a passes over the small diameter part 2a and fits into the large diameter part 2b. As a result, the spring 3 is attached to the fixed part 2 of the piston 1, and its enlarged diameter part 3a is caught on the fixed part small diameter part 2a, and the spring 3 is reliably prevented from coming off.

Note that if the diameter C of the fixed portion large diameter portion 2b is set equal to or slightly larger than the diameter E of the expanded diameter portion 3a of the spring 3 (C
≦E), the spring 3 can be fixed more reliably, and the spring can be more reliably prevented from tilting, thereby preventing interference between the spring 3 and the housing 11.

Further, the expanded diameter portion 3a of the spring 3 may be configured to have a large diameter for one turn as shown in FIG. 5(a), but as shown in FIG. 5(b), the end a is The spring 3 is bent in the radial direction, so that the spring 3 is sometimes attached.
It may be arranged to prevent the end a from damaging the fixing part 2 and causing cracks or the like.

Furthermore, as shown in FIG. 5(0), the spring expanded diameter portion 3
A may be formed into an ellipse whose short diameter portion has approximately the same diameter as the normal coil diameter, and the elongated portions (protruding portions) b and b' of the ellipse may be fitted into the large diameter portion 2b of the fixed portion. In addition, as shown in FIG. 5(d), the enlarged diameter portion 3a is configured in a triangular shape that protrudes radially outward at three locations, and the protrusions C, Q', and C" It may be fitted into the large diameter portion 2b.In this case, one of the protruding portions S, C, C' is first inserted into the large diameter portion 2b, and the remaining one is inserted into the large diameter portion 2b.
Large diameter part 2 by pushing in protruding part b' or C' of the cylinder.
When the spring is inserted into the spring, the remaining protruding portion b' or C'' is easily bent in the radial direction, so that the spring can be attached very easily.

(G) As described in detail, according to the present invention, the expanded diameter portion 3a of the spring 3 having a larger diameter than the small diameter portion 2a of the spring fixing portion 2 is located on the back side of the small diameter portion 2a. Since it fits into the large diameter portion 2b and fixes the spring 3 to the end surface of the piston,
Although it is extremely easy to install,
- Once the eaves are attached, they will not come off (and the fixing part 2 for attaching them has an extremely simple structure and requires only a small amount of space.

Furthermore, a spring 3 is located in the accumulator chamber 5;
When applied to a piston with a natural length shorter than the stroke of the piston 1, it is possible to prevent the spring 3 from tilting and prevent the spring 3 from interfering with the housing 11, and to maintain smooth movement of the piston 1. The concave portion of the spring fixing portion 2 that serves as an air reservoir can be configured to be small, and even if air accumulates due to toilet use, the influence of the air can be reduced and the set accumulator characteristics can be maintained at all times.

Further, by bending the enlarged diameter side end a of the spring 3 in the radially inward direction, it is possible to prevent scratches and cracks from occurring when the spring is attached.

Furthermore, a tapered surface 2 is formed between the piston end surface 1a and the small diameter portion 2a, the diameter of which gradually decreases from the piston end surface toward the small diameter portion.
If C is selected, the spring 3 can be attached extremely easily.

Further, if the expanded diameter portion 3a of the spring is composed of a plurality of protrusions (c) that protrude radially outward, the spring 3 can be attached more easily and is less likely to come off.

[Brief explanation of drawings]

FIG. 1 is a diagram showing different left and right states of the accumulator according to the present invention along the center line, FIG. 2 is an enlarged sectional view showing a spring fixing part, and FIG. 3 is an enlarged sectional view showing a state in which a spring is attached. . FIG. 4 is an exploded view showing the spring and piston, and FIGS. 5(a) to 5(d) are plan views showing the enlarged diameter portion of the spring showing different embodiments. 1...Piston, 1a...End face, 2.
...Spring fixing part, 2a...Small diameter part, 2
b...Large diameter part, 2C...Tapered surface, 3...
・Spring, 3a... Expansion portion, 5... Accumulator chamber, A... Accumulator, B
...Small wire diameter, E...Expanded diameter, a...
Ends, b, c... protruding parts.

Claims (5)

[Claims] (1) A piston that is slidably inserted into the cylinder chamber,
In an accumulator comprising a spring that urges the piston, a concave spring fixing part is formed on the end surface of the piston, the part having a small diameter and the back side having a large diameter part; An accumulator configured by forming an enlarged diameter part having a larger diameter than the small diameter part of the spring fixing part, and fitting the enlarged diameter part into the large diameter part to fix the spring to the piston. (2) the spring is located in an accumulator chamber;
The accumulator according to claim 1, wherein the accumulator has a natural length that is shorter than a stroke of the piston. (3) The accumulator according to claim 1, wherein a space between the piston end face and the small-diameter portion in the spring fixing portion is a tapered surface whose diameter gradually becomes smaller from the piston end face toward the small-diameter portion. (4) The accumulator according to claim 1, wherein the expanded end of the spring is bent in a radially inward direction. (5) The accumulator according to claim 1, wherein the expanded diameter portion of the spring comprises a plurality of protrusions that protrude in a radially outward direction.