JP3253254B2 - Center valve type 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 center valve type master cylinder used for a hydraulic brake device and a hydraulic clutch device for a vehicle, and more particularly, to a retainer for maintaining stable positioning of a valve body in a center valve. Related to the support structure.

[0002]

2. Description of the Related Art As a conventional technique of this kind, there is, for example, Japanese Utility Model Laid-Open No. 1-161165. As shown in FIG. 5, a cylinder hole 3 is formed inside a main body 2 of the conventional center valve type master cylinder 1, and a hydraulic pressure chamber 4 and a large pressure chamber are formed by a piston 5 slidably fitted into the cylinder hole 3. An air pressure chamber 19 is defined. A recess 6 is formed at the tip of the piston 5 on the hydraulic pressure chamber 4 side, and a center valve mechanism 9 is provided in the recess 6. The piston 5 is formed with an axial passage 7 and a hole 18 for communicating the hydraulic pressure chamber 4 with the atmospheric pressure chamber 19.
0 communicates with the inside of a reservoir (not shown).

The center valve mechanism 9 has a valve seat 10 formed at the bottom of the recess 6, a valve body 11 that can be attached to and detached from the valve seat 10, and biases the valve body 11 against the valve seat 10. Spring 12
And a stem 13 extending from the valve body 11 to the axial passage 7 of the piston 5, and fluid communication between the fluid pressure chamber 4 and the recess 6 is possible.
A retainer 14 with which one end of a spring 12 is engaged, and a pin member 1 which is disengaged from the stem 13 in response to the movement of the piston 5
5 is provided. The pin member 15 is loosely fitted in the long hole-shaped radial passage 8 penetrating the piston 5 in the radial direction, and both ends thereof are supported by a cylindrical guide member 17 for guiding the movement of the piston 5. . The outer peripheral edge of the retainer 14 is formed by a stepped portion 21 formed at the opening end of the peripheral wall 6 a of the recess 6.
To be engaged.

FIG. 5 shows a non-operating state of the center valve type master cylinder 1. The valve body 11 is brought into contact with the stem 13 and the pin member 15 so that the valve body 11 resists the spring force of the spring 12 and the valve seat 10 moves. Have been away from As a result, the center valve mechanism 9 assumes the valve-open state, and connects the hydraulic chamber 4 to the axial passage 7,
It communicates with a reservoir (not shown) through the hole 18, the atmospheric pressure chamber 19 and the supply hole 20. Return spring 1
When the piston 5 is driven against the spring force of the spring 6, the spring 1
The valve element 11 is seated on the valve seat 10 by the spring force of 2, thereby closing the center valve mechanism 9 and generating a hydraulic pressure in the hydraulic pressure chamber 4. The generated hydraulic pressure is supplied from an output port 22 to a brake device for a wheel (not shown) so as to perform a known braking action.

[0005]

However, in the conventional center valve type master cylinder 1, if the valve body 11 of the center valve mechanism 9 is repeatedly put on and taken off, the peripheral wall 6a of the recess 6 and the retainer 14 And the engagement force between the valve body 11 and the valve body 11 may not be able to be accurately positioned. That is, when the retainer 14 moves relative to the peripheral wall 6a of the recess 6 toward the hydraulic pressure chamber 4 side, the spring force of the spring 12 may fluctuate depending on the amount of movement, so that the accurate positioning of the valve body 11 is achieved. There is a problem that can not be. This leads to an increase in the ineffective stroke of the piston 5, and as a result, adversely affects the seating action of the valve body 11 on the valve seat 10, and makes it impossible to perform the intended braking action. Further, the retainer 14 may fall out of the recess 6.

In order to avoid this, Japanese Utility Model Laid-Open Publication No.
There is one described in JP-A-62. In this publication, the outer periphery of the retainer is brought into contact with a predetermined step of the recess at the tip of the piston on the hydraulic pressure chamber side, and then the C-shaped section is formed on the hydraulic chamber side (rear side) of the retainer. The retainer is supported and positioned by elastically deforming a C-ring (C-type concentric retaining ring) and fitting it into a groove formed at a predetermined position on the peripheral wall of the recess, thereby performing stable positioning of the valve element. Like that.

However, with such technical means,
A C-ring is required, and an operation of fitting the C-ring to a predetermined position after fitting the retainer into the recess is required. Not only can the retainer not be positioned unless this C-ring fits into the groove in the peripheral wall,
In the mounting operation of the C-ring, the C-ring cannot be mounted in the above-mentioned groove depending on how to apply a force applied to the elastic deformation of the C-ring, and accurate positioning of the retainer cannot be performed. Therefore, there is a problem that the number of parts increases and the assembling operation takes time, which leads to a decrease in productivity.

It is an object of the present invention to provide a center valve type master cylinder capable of facilitating an assembling operation and accurately positioning a retainer for a long period of time. .

[0009]

The object of the present invention is to provide a main body having a cylinder bore, a piston slidably fitted in the cylinder bore to define a hydraulic chamber, and a hydraulic fluid formed at the tip of the piston. A recess that opens toward the pressure chamber, and a center valve that is disposed in the recess and that opens and closes a liquid passage between the hydraulic chamber and the reservoir in accordance with the movement of the piston. A valve seat formed at the bottom of the recess, a valve element that can be attached to and detached from the valve seat, a spring that urges the valve element to the valve seat, and an inner hole of the piston from the valve element A center valve including an extending stem, a retainer capable of fluid communication between the hydraulic chamber and the inside of the recess and engaging one end of the spring, and a pin member engaged and disengaged from the stem in response to movement of the piston. In the mold master cylinder, the peripheral wall of the recess is With an annular groove in which the retainer is fitted is formed, the retainer is a plate-like member formed
Will be shaped, to the retainer, the central has a plurality of arm portions are formed to one end engaging the radially projecting said spring radially outward from, among the plurality of arms, at least one pair is Elastically deformed from the opening side of the recess and fitted into the groove.
The center valve type master cylinder is characterized in that the remaining arm portion is a claw portion shorter than the opening diameter of the recess.

An annular groove into which the retainer is fitted is formed in the peripheral wall of the recess, and a plurality of arms are formed in the retainer so as to project radially outward from the center thereof. At least one pair of the arms is elastically deformed from the recess opening side.
By making the locked portion fitted into the groove and the remaining arm a claw shorter than the opening diameter of the recess, the retainer is assembled by elastically deforming the locked portion of the retainer. Work is easy because it is only required to fit into the groove.
Accurate positioning with respect to the valve body can be maintained for a long period of time while reliably positioning the retainer with respect to the peripheral wall of the recess without using the conventionally used C-ring.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A center valve type master cylinder according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main part of a center valve type master cylinder according to the present embodiment, which is indicated by reference numeral 31. Body 3
2, a piston (secondary piston in the present embodiment) 35 having cup seals 47 and 48 mounted on its outer periphery is slidably fitted in the cylinder hole 33. ing. This allows
A hydraulic chamber (a second hydraulic chamber in the present embodiment) 34 is defined between the piston 35 and the bottom wall 33a of the cylinder hole 33. A return spring 46 is provided between the spring receiving portion 35a of the piston 35 and the bottom wall 33a of the cylinder hole 33.
Are provided in a pre-loaded state, whereby the piston 3
5 is biased rightward in the figure.

A recess 36 is formed at the tip of the piston 35 and opens toward the hydraulic chamber 34. A center valve mechanism 39 is provided inside the recess 36. The center valve mechanism 39 includes a valve seat 40 formed at the bottom of the recess 36 and a valve body 41 that can be attached to and detached from the valve seat 40.
A spring 42 for urging the valve body 41 toward the valve seat 40; and an axial passage 3 of the piston 35 formed integrally with the valve body 41.
7, a fluid communication between the hydraulic chamber 34 and the recess 36 is possible, and a retainer 44 with which one end of a spring 42 is engaged.
And a pin member 45 which is engaged and disengaged.

The pin member 45 extends from a supply hole 53 formed in the bottom of the internal recess 52 of the boss portion 51 formed on the outer periphery of the main body 32 to a long hole 35b formed in the body of the piston 35.
And one end thereof is supported by the opposed cylinder wall. The other end of the pin member 45 is supported by a nipple portion 58 of a reservoir that is fitted into the internal recess 52 of the boss portion 51 via a sealing member 57. An atmospheric pressure chamber 49 defined between the cup seals 47 and 48 is always in communication with the inside of the reservoir via a groove 45a formed on the outer periphery of the pin member 45. The recess 36 communicates with the hydraulic chamber 34 through a through hole 35c formed in the piston 35 and a retainer 44 described later.

The retainer 44 according to the present invention has a shape as shown in FIGS. 3 and 4, and is formed by pressing a plate-like member . The retainer 44 includes a plurality of locked portions 44 a and a plurality of claw portions 44 radially projecting radially outward from the center thereof.
Ri consists is b, and includes an arm portion for one end engaging the spring 42. In the present embodiment, the locked portion 44a and the claw portion 4
4b are formed at four places each, and the locked portions 44a and the claw portions 44b are provided alternately in the circumferential direction, and are located opposite to each other. As shown in FIG. 4, the locked portion 44a and the claw portion 44b are formed by bending in the axial direction and the radial direction at right angles. Each locked part 4
The end of 4a has a locking body 70 fitted to the peripheral wall 36a of the recess 36 of the piston 35. A gap is formed between the adjacent locked portion 44a and the claw portion 44b, and a communication hole 44c is formed at the center of the retainer 44. As a result, liquid communication between the hydraulic chamber 34 and the inside of the recess 36 is possible.

On the other hand, the peripheral wall 36 of the recess 36 of the piston 35
An annular groove 55 into which the locked portion 44a of the retainer 44 is fitted is formed in a. In the present embodiment, with reference to FIG. 2, the opening diameter D ₁ of the recess 36, the groove 55
3 is smaller than the diameter D ₂ of the groove bottom of
6, that is, larger than the inner diameter D ₃ of the peripheral wall on the valve seat 40 side (the right side in the figure), and the axial length L of the groove 55 is the same as that of the locked portion 44 a of the retainer 44. The length of the locking body 70 is substantially the same as the length h. The radial length of the claw portion 44 b of the retainer 44 is shorter than the opening diameter D ₁ of the recess 36.

[0017] Therefore, when attaching the retainer 44 to the peripheral wall 36a groove 55 of the recess 36, easily retainer 44 by elastically deforming the engaged portion 44a larger than the opening diameter D ₁ of the recess 36 The locking member 70 of the locked portion 44 a can be fitted into the groove 55 formed in the peripheral wall 36 a of the recess 36.
At this time, since the locking body 70 is restricted from moving in the axial direction in conformity with the groove 55, the retainer 44 can be reliably positioned at a predetermined position inside the recess 36. Also, groove 5
5, the inner diameter D ₃ of the peripheral wall on the valve seat 40 side is the opening diameter D of the recess 36.
Since it is smaller than _1, it is possible to prevent the locked portion 44a of the retainer 44 fitted into the recess 36 from going over the groove 55 and further immersing into the valve seat 40 side.

In this embodiment, two pairs of the locked portions 44a of the retainer 44 are provided at positions facing each other, and the claw portions 44b as the remaining arms are formed by the locked portions 44a. Since they are evenly arranged therebetween, it is possible to prevent the retainer 44 from rattling due to the hydraulic pressure acting on the retainer 44 on the concave 36 side and the hydraulic pressure chamber 34 side. Further, a communication hole 44c is provided at the center of the retainer 44,
Further, since a gap is formed between the locked portion 44a and the claw portion 44b, a large passage for the hydraulic fluid to flow between the concave portion 36 and the hydraulic chamber 34 can be provided. it can.

Next, the operation of the center valve type master cylinder 31 configured as described above will be described.

FIG. 1 shows a non-operating state of the master cylinder 31. The valve body 4 is brought into contact with the stem 43 and the pin member 45.
1 is separated from the valve seat 40 against the spring force of the spring 42. As a result, the center valve mechanism 39 is opened, and the hydraulic chamber 34 communicates with the reservoir 58 via the axial passage 37, the elongated hole 35b, the atmospheric pressure chamber 49, and the supply hole 53. Depressing a brake pedal (not shown)
The piston 35 is opposed to the spring force of the return spring 46.
Is driven, the contact state between the stem 43 and the pin member 45 is released, and the valve body 41 is seated on the valve seat 40 by the spring force of the spring 42, thereby closing the center valve mechanism 39. Then, a hydraulic pressure is generated in the hydraulic pressure chamber 34. The generated hydraulic pressure is supplied to a brake operating device (not shown), and a known braking operation is performed. When the depression of the brake pedal is released, the piston 35 returns to the illustrated position by the spring force of the return spring 46, the center valve mechanism 39 is opened, and the hydraulic pressure chamber 34 and the atmospheric pressure chamber 49 are again in a communication state. Become.

According to the present embodiment, since the retainer 44 of the center valve mechanism 39 can be reliably positioned with respect to the peripheral wall 36a of the recess 36, the valve body 41 is moved toward the valve seat 40. The accurate positioning of the valve body 41 can be maintained for a long period of time by keeping the spring force of the spring 42 biased.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical concept of the present invention.

For example, in the above embodiment, the retainer 4
Four arm portions are formed of eight, and four of them are locked portions 44a.
However, instead of this, two locked portions may be formed at opposing positions, and the remaining arm portion may be formed as a claw portion. The number of arms is not limited to this, and the number may be further increased or decreased.

In the above embodiment, the secondary piston has been described. However, it is needless to say that the primary piston can be similarly configured.

Further, the center valve type master cylinder 3
When the assembly 1 is assembled by an automatic assembly line, the retainer 44 according to the present invention can be automatically supplied by a vibrating parts feeder. At this time, even if the arms of the retainer are entangled in the storage part of the vibrating parts feeder for storing the retainer 44, the arms can be separated by the vibration of the vibrating parts feeder, so that there is no problem.

[0026]

As described above, according to the center valve type master cylinder of the present invention, since the locked portion of the retainer is merely elastically deformed and fitted into the groove of the peripheral wall of the recess, the work is easy. In addition, since the retainer can be reliably positioned with respect to the peripheral wall of the recess, accurate positioning with respect to the valve body can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a center valve type master cylinder according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing an engaged state of a retainer in FIG.

FIG. 3 is an enlarged front view of a retainer according to the present invention.

FIG. 4 is a sectional view taken along the line [4]-[4] in FIG.

FIG. 5 is a sectional view showing a main part of a conventional center valve type master cylinder.

[Explanation of symbols]

 31 Center Valve Master Cylinder 32 Main Body 33 Cylinder Hole 34 Hydraulic Pressure Chamber 35 Piston 36 Recess 36a Peripheral Wall 39 Center Valve Mechanism 40 Valve Seat 41 Valve 42 Spring 43 Stem 44 Retainer 44a Locked Portion 44b Claw 44c Communication Hole 45 Pin member 55 Groove 70 Locking body

Claims (4)

(57) [Claims] 1. A main body having a cylinder hole, a piston slidably fitted in the cylinder hole to define a hydraulic chamber, and a recess formed at the tip of the piston and opening toward the hydraulic chamber. And a center valve disposed in the recess to open and close the fluid passage between the hydraulic chamber and the reservoir in accordance with the movement of the piston. The center valve is formed at the bottom of the recess. A valve seat, a valve body that can be attached to and detached from the valve seat, a spring that urges the valve body against the valve seat, a stem extending from the valve body to an inner hole of the piston, and the hydraulic pressure chamber. In a center valve type master cylinder including a retainer capable of communicating with the inside of the recess and engaging one end of the spring and a pin member engaging and disengaging the stem in response to movement of the piston, the peripheral wall, ring the retainer is fitted With the <br/> grooves are formed, the retainer is plate-like member
Molded becomes, the on the retainer, the central has a plurality of arms which at one end engage with radially projecting said spring is formed radially outward from, among the plurality of arms, at least one pair is Elastic deformation from the opening side of the recess fits into the groove
A locked portion which is in the center valve type master cylinder, wherein the arm portion of the remainder being shorter claw portion than the opening diameter of the recess. 2. The method according to claim 1, wherein the at least one pair of locked portions is disposed at a position facing each other, and the claw portions are uniformly disposed between the locked portions. The center valve type master cylinder according to claim 1. 3. A gap is formed between adjacent arms, and a communication hole is formed at the center of the retainer. The recess and the liquid are formed by the gap and the communication hole. 3. The center valve type master cylinder according to claim 1, wherein liquid communication with the pressure chamber is provided. 4. An opening diameter of the recess is smaller than a diameter of a groove bottom of the groove, and is larger than an inner diameter of a peripheral wall of the recess on a bottom side of the groove. The center valve type master cylinder according to any one of claims 1 to 3, wherein the length in the axial direction is substantially the same as the length of the locking body of the locked portion.