JP2573004Y2 - Return spring for master cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a return spring for a master cylinder.

[0002]

2. Description of the Related Art A master cylinder employed in a brake device operates a piston by depressing a brake pedal, and the piston causes liquid in a pressure chamber to be pumped to a wheel cylinder. When the depression force of the brake pedal is released, the piston is returned to the original position by the urging force of the return spring.

[0003]

By the way, in such a master cylinder, as shown in FIG.
A return spring 3 is arranged between the end wall 1a of the piston 2 and the end 2a of the piston 2. The return spring 3 is positioned by narrowing its end 3 a and fitting the end 3 a to a projection 2 b formed at the tip of the piston 2.

However, it is generally difficult to form the end 3a of the spring 3 so as to be in close contact with the projection 2b over the entire circumference, and the spring 3 cannot be fixedly held on the projection 2b of the piston 2.

That is, as shown in FIG.
When the inner diameter of the end 3a is larger than the outer diameter of the projection 2b, the spring 3 contacts the projection 2b only at one point, for example, at the point A, and as shown in FIG. When the spring 3 is simply contracted, the spring 3 contacts the protrusion 2b only at two points, for example, at points B and C. In the former case, the spring 3 is supported in a state of rattling on the projection 2b, so the attitude of the spring is not determined at all. In the latter case, the spring 3 is held by the projection 2b at the points B and C. However, the spring 3 swings about the line connecting the points B and C.

Therefore, in the conventional master cylinder,
When the return spring 3 is assembled in the cylinder 1, there is a possibility that the free end 3b of the return spring 3 may damage the peripheral wall 1b of the cylinder 1.

Accordingly, an object of the present invention is to provide a master cylinder return spring which can be fixedly held on a projection of a piston.

[0008]

In the present invention the master cylinder return spring Means for Solving the Problems] are perpendicular to the mandrel with a one volume of one end of the return spring to vertically into positioned with respect to the axial center of the return spring Diameter reduction along the direction
And, the one volume of that by abutting at three or more locations on the peripheral surface of the projection is formed into a non-circular so as to fixedly held in the projections.

[0009]

In the master cylinder return spring according to the present invention, the spring contacts the protrusion of the piston at three or more end portions. Therefore, the spring is fixedly held by the projection.

[0010]

FIG. 1 shows a master cylinder provided with a return spring according to the present invention, and FIGS. 2 and 3 show an enlarged view of a main part thereof.

In the master cylinder 10, a primary piston 13 and a secondary piston 14 are disposed in a cylinder 12 of a cylinder main body 11, and the primary piston 13 and the secondary piston 14 are provided.
Primary piston 13 and secondary piston 14
Thereby, the inside of the cylinder 12 is defined as a first pressure chamber 15 and a second pressure chamber 16. Outlets 17 and 18 are formed in the first pressure chamber 15 and the second pressure chamber 16, respectively.
The outlets 17 and 18 are connected to wheel cylinders and the like of each brake system.

Flanges 19 and 20 slidingly contacting the cylinder 12 are formed at the leading end and the rear end of the primary piston 13, and flanges 21 and 20 slidingly contacting the cylinder 12 are also formed at the leading and trailing ends of the secondary piston 14.
2 are formed. And those flanges 19,
20, 21, 22 include cup packings 23, 24, 2;
5, 26 are attached.

A bolt 27 is implanted at the tip of the primary piston 13, and a retainer 28 is fitted to the bolt 27, and the cup packing 23 is held on the primary piston 13 by the retainer 28. A columnar projection 1 is provided at the tip of the secondary piston 14.
4a, and the retainer 2 is formed on the projection 14a.
9 is fitted, and the cup packing 25 is held on the secondary piston 14 by the retainer 29.

A hat-shaped retainer 30 is provided at the rear end of the secondary piston 14, and the bolt 27 is inserted through the top of the retainer 30. A return spring 31 is interposed between the retainers 28 and 30.

Further, as shown in FIG. 2, the retainer 29 of the secondary piston 14 and the end wall 12a of the cylinder 12
Also, a return spring 32 is interposed between them. In this return spring 32, one turn 32a at one end is disposed substantially perpendicular to the axis of the return spring 32, and the turn 32a is formed in a substantially triangular shape as shown in FIG. ing.

The return spring 32 is
One end thereof is fitted around the projection 14a of the secondary piston 14 so as to be wound therearound. In this way, the return split <br/> ring 32 fitted to the projection 14a of the secondary <br/> piston 14, as shown in FIG. 3, substantially in one turn 32a at one end of the return spring 32 Each side of the triangle contacts the peripheral surface of the projection 14a at three locations D, E, and F.

Therefore, the return spring 32
Is fixedly held by the projection 14a of the secondary piston 14.

The contact point F is set at the spring end 32.
The portion excluding b is preferable. This is the spring end 32
This is to prevent the peripheral surface of the projection 14a from being damaged by b. Further, it is preferable that the contact points D, E, and F are arranged at substantially equal intervals. This is return spring 3
2 in order to fixedly securely held in the projection 14a.

[0019] The return spring 32, in advance Seca
After it mounted on the Secondary piston 14, cylinder 12 of the cylinder body 11 together with the secondary <br/> piston 14
Will be incorporated within.

[0020]

As described above, in the return spring for the master cylinder according to the present invention, one turn of the end is formed by a surface perpendicular to its axis on the peripheral surface of the projection formed at the tip of the piston. To abut at three or more locations within
The piston is fixedly held concentrically with the projection of the piston.

Therefore, when assembling the piston to the cylinder body, the spring can be incorporated into the cylinder without the free end of the spring coming into contact with the cylinder peripheral surface of the cylinder body, thereby damaging the inner peripheral surface of the cylinder. There is no fear.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a master cylinder having a return spring according to the present invention.

FIG. 2 is a sectional view showing a main part of FIG.

FIG. 3 is a sectional view showing a state in which the return spring according to the present invention is attached to a piston.

FIG. 4 is a sectional view showing a main part of a conventional master cylinder.

FIG. 5 is a cross-sectional view showing an example of a state in which a return spring in a conventional master cylinder is attached to a piston.

FIG. 6 is a cross-sectional view showing another example of a conventional master cylinder in which a return spring is attached to a piston.

[Explanation of symbols]

 Reference Signs List 10 master cylinder 11 cylinder body 12 cylinder 12a end wall 14 secondary piston 14a projection 16 second pressure chamber 25 cup packing 29 retainer 32 return spring 32a one turn

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norihide Sasaki 1-26-10 Bessho, Urawa-shi, Saitama Co., Ltd. Taga Works Co., Ltd. (56) References Hikaru 3-51105 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylindrical protrusion is formed at the tip of the piston, the master return spring cylinder which is HaiSo with one end fitted projecting into force, the return of one volume of one end of the return spring in a direction perpendicular to the mandrel as well as vertically into positioned with respect to the axial center of the spring
Along reduced in diameter, the one volume of that by abutting at three or more locations on the peripheral surface of the protrusion return master cylinder characterized by being formed in a non-circular so as to fixedly held in the projections spring .