JPH063731Y2 - Master cylinder with hydraulic control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a master cylinder with a hydraulic pressure control valve used for a two-system brake system, and particularly, when one system fails, The present invention relates to an improvement of the hydraulic pressure control function that can be released.

(Prior Art) In this type of master cylinder with hydraulic control valve, the main piston and the slave piston are slidably inserted into the cylinder hole, and the main pressure chamber, the slave piston and the cylinder hole are inserted between these two pistons. Each of the auxiliary pressure chambers is partitioned from the bottom portion, and a hydraulic pressure control valve is attached to the discharge portion formed in communication with the main pressure chamber. The hydraulic control valve has a plunger biased by a spring having a predetermined preload, and a poppet arranged so as to face a valve seat formed on the plunger.

The fluid pressure control valve is in an open state in which the poppet is separated from the plunger-side valve seat when the fluid pressure is below a predetermined value, but when the fluid pressure exceeds a predetermined value, it is in a closed state in which the poppet is seated on the plunger-side valve seat. . As a result, in the hydraulic pressure control valve, when the hydraulic pressure exceeds the predetermined value, the hydraulic pressure on the inlet side communicating with the main pressure chamber (this hydraulic pressure is the same as the hydraulic pressure on the front wheel side). ,
The hydraulic pressure on the outlet side that communicates with the brake device on the rear wheel side is controlled to be reduced.

However, if such control by the hydraulic control valve is performed even when a failure occurs in the brake circuit on the front wheel side, a problem of insufficient braking force will occur. Therefore, conventionally, when the system on the front wheel side fails, the hydraulic pressure control function of the hydraulic pressure control valve is canceled. Specific examples thereof include European Patent Application Publication No. 0157158.
As described in Japanese Patent Publication No. JP-A-2003-264, there is known a technique in which when the secondary piston excessively strokes, the flange portion pushes the side portion of the poppet and swings the poppet so that the poppet is separated from the valve seat on the plunger side. Has been.

(Problems to be solved by the invention) In the conventional technology in which the poppet is directly pushed to oscillate, a part of the poppet must be projected into the hole of the master cylinder, so the hydraulic control valve is installed. If left as it is, the piston cannot be taken out of the cylinder hole for parts replacement or the like.

In addition, since a part of the slave piston pushes the poppet directly to the side, excessive force may be applied to the poppet due to dimensional accuracy restrictions, which may damage the poppet or cause the rocking poppet to move to the cylinder. It may damage the inner wall of the hole and damage the piston cup.

As a means to solve the above problems, the poppet side is not tilted directly by utilizing the excessive stroke of the secondary piston, but the movement of the plunger side is also used to indirectly tilt the poppet. A method of releasing the pressure regulating function of the hydraulic pressure control valve can be considered. However, when the method is adopted, since a force based on a predetermined hydraulic pressure difference acts on the plunger, it is desirable to avoid the harmful effects of the relatively large force as much as possible.

This invention was made in consideration of the above points,
The present invention provides a suitable technique that employs a method of utilizing a movement on the side of a plunger for tilting a poppet.

(Means for Solving the Problems) In the present invention, as shown in the attached drawings corresponding to the embodiment, particularly as shown in FIG. 1, an extension portion 52 is formed integrally with the end portion of the plunger 42 on the poppet side so as to extend away from the poppet 48. The extension piston 52 can be projected into the cylinder hole 12 according to the movement of the plunger 42.
The auxiliary member 54, which can be engaged with the moving body 16b in the cylinder hole at the time of excessive stroke, is movably engaged while being urged to the main pressure chamber 24 side by the spring 56 to assist the poppet 48 and the auxiliary member 54. It is fitted so that it can be tilted according to the tilt of the member. Then, the length of the auxiliary member 54 is set to the plunger 4
It is set so as not to project into the cylinder hole 12 when the second valve is not operated.

(Operation) When the hydraulic control valve 70 is in the non-operating state, the plunger 42
Is in a stationary state as shown in FIG. 1, and the tip of the auxiliary member 54 that moves according to the movement of the plunger 42 does not project into the cylinder hole 12. Therefore, the sub piston 16 can be taken out from the inside of the cylinder hole 12 regardless of the presence or absence of the hydraulic control valve 70.

However, on the other hand, in the operating state of the hydraulic control valve 70, the upper portion of the auxiliary member 54 projects into the cylinder hole 12 according to the movement of the plunger 42. By the way, when a failure occurs in the brake circuit on the front wheel side and the secondary piston 16 is excessively stroked, the flange portion 16b of the secondary piston 16 causes the plunger 4 to move.
2, that is, to a position facing the auxiliary member 54. Therefore, as shown in FIG. 3, the auxiliary member 54 has its head pressed by the collar portion 16b and tilts, and accordingly tilts the poppet 48 to release the control function of the hydraulic control valve 70. In this case, the auxiliary member 54 is the spring 56.
, The spring 56 functions as a buffer spring, effectively preventing unreasonable force from being applied to each component around the auxiliary member 56.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is the basis. FIG. 1 is a cross-sectional view of a tandem master cylinder equipped with a hydraulic pressure control valve in the vicinity of the hydraulic pressure control valve, with the plunger 42 in a non-operating state. On the other hand, FIG. 2 is a sectional view showing the hydraulic pressure control valve when the plunger 42 operates normally.

A cylinder hole 12 having a uniform diameter and extending along the axis is formed in the cylinder body 10 of which only a part is shown. A sub piston 16 having a piston cup 14a and a main piston 18 having a piston cup 14b are slidably inserted into the cylinder hole 12. Both pistons 1
6 and 18 have the same axis, and their intervals are defined by a cup-shaped retainer 20 and a bolt 22. The chamber 24 defined by the cup seals 14a and 14b between the two pistons 16 and 18 is the main pressure chamber, and the chamber between the sub piston 16 and the bottom of the cylinder hole, which does not appear in the figure, is the sub pressure chamber. is there. In the main pressure chamber 24 and the sub pressure chamber,
A return spring 26 is provided for each of the pistons 16, 18
Is in the return position as shown in the figure unless the pressing force from the push pad is applied to the right end of the main piston 18. In this return position, the piston cup 1 of the main piston 18
A release hole 28 and a hydraulic fluid supply hole 30 communicating with a reservoir (not shown) are located on both sides of 4b, and a hydraulic pressure control valve 70 is provided on the right side of the piston cup 14a of the slave piston 16.
A discharge hole 32 that serves as a communication passage to is located.

The housing 34 of the hydraulic control valve 70 is composed of two members 34a and 34b which are screwed to each other with the seal portion 36 interposed therebetween. The housing 34 has one member 34.
Cylinder body 10 with the end of a sandwiching pressure seal 38
Is connected to the discharge hole 32 by being screwed to the boss portion 10a of the, while the outlet 40 is provided at the end of the other member 34b,
A pipe connecting to the wheel cylinder on the rear wheel side is connected thereto. A through hole 42 is formed in the center of the housing 34.
A stepped plunger 42 having a is provided.
The plunger 42 has a small diameter portion 42b on the upper side, a medium diameter portion 42c on the lower side, and a large diameter flange portion 42d in the middle thereof. The plunger 42 receives the force of the preload spring 44 applied via the flange portion 42d, and the upper and lower two
It can be moved up and down by being guided at the location. Plunger 42
In the stage where the hydraulic pressure is low, the force of the preload spring 44 causes the midway flange portion 42d to move toward the member 34b.
At the time of c, it is in a stationary state as shown in FIG. However, when the hydraulic pressure increases and the force acting on the effective difference area portion defined by the seal rings 46a and 46b around the plunger 42 overcomes the force of the preload spring 44, the plunger 4
2 moves to the upper side of the figure and becomes a state as shown in FIG. As a result, when the central protruding portion 48a of the poppet 48 is seated on the valve seat 42e at the upper end of the plunger 42, the hydraulic pressure control valve 70 thereafter controls the hydraulic pressure on the outlet 40 side to the main pressure chamber 24.
Control the hydraulic pressure compared to the side.

The plunger 42 is located in the chamber 50 adjacent to the discharge hole 32, and the periphery thereof is surrounded by a box-shaped member 52 having an upper opening and an auxiliary member 54 combined with the box-shaped member 52. The box-shaped member 52 receives the end of the small-diameter portion 42b of the plunger 42 in a hole in the central portion of the bottom and is integrated with the plunger 42, and functions as an extension of the plunger 42. This extension 52 is also a member 34 that partitions the chamber 50.
It moves together with the plunger 42 along the inner wall of a.
The box-shaped member 52 as an extension is provided with a hole 52a through which the pin 48b of the poppet 48 is inserted and a protrusion 52b for preventing the auxiliary member 54 from coming off at the upper end.

Further, the auxiliary member 54 includes a tubular portion 54a having an inner diameter suitable for the diameter of the shaft portion 48c of the poppet 48, and a flange portion 54b located at the lower end of the tubular portion 54a. The auxiliary member 54 includes a shaft portion 4 of the poppet 48 inside the tubular portion 54a.
8c, the flange portion 54b is extended 52
It is engaged with the extension portion 52 by being inserted into the inner circumference of the. The poppet 48 is housed in the extended portion 52 and the auxiliary member 54, which are assembled together in this manner, in a form biased downward by the spring 56. The poppet 48 uses the force of the spring 56 to move the lower pin 48b to the step 34d on the member 34a side.
The flange portion 54b of the auxiliary member 54 is applied to the protrusion 52b. However, the shaft portion 4 of the poppet 48
8c does not extend beyond the cylindrical portion 54a of the auxiliary member 54, and when the hydraulic pressure control valve 70 shown in FIG. It doesn't go inside. In addition, the cutout passage 58a and the through hole 58b provided in the poppet 48.
Is for securing a liquid passage.

When the hydraulic pressure increases, the plunger 42 moves upward as shown in FIG. 2, and the central protrusion 48a of the poppet 48 is seated on the valve seat 42e at the upper end of the plunger 42 to control the rear wheel pressure reduction. Do. At this time, the extension portion 5 of the plunger 42
2 also moves with the plunger, and accordingly, the spring 5
The upper portion of the cylindrical portion 54a of the auxiliary member 54 biased by 6 projects into the cylinder hole 12 by a predetermined amount. By the way, if the system on the front wheel side fails, the secondary piston 16 immediately makes an excessive stroke, and the flange portion 16b at the tip of the tubular portion 16a.
Are opposed to the discharge holes 32. Therefore, at such an upper end, when the hydraulic pressure increases and the plunger 42 moves upward, the movement of the plunger 42 itself is not suppressed, but the upper portion of the auxiliary member 54 has the flange portion 1 of the slave piston 16.
When it hits 6b, its upward movement is restricted and it tilts as shown in FIG. In accordance with the inclination of the auxiliary member 54, the inner poppet 48 also inclines, and the seating on the valve seat 42e becomes impossible. That is, the hydraulic pressure control valve 70 is in a state in which the pressure adjusting function is released. In this case, the upper end of the auxiliary member 54 touches the flange portion 16b of the secondary piston 16 to apply a force,
The force is small due to the deformation of the spring 56. Therefore, such a small force does not cause inconvenience such as twisting of the secondary piston 16. In order to smoothly incline the auxiliary member 54 and the poppet 48, it is preferable to provide the collar portion 16b with an appropriate tapered surface 16c as in the embodiment. Also,
In the embodiment, as the spring 56 that biases the auxiliary member 54,
Since the valve spring that biases the poppet 48 toward the valve seat 42e is used, the structure can be simplified.

In the embodiment shown in the drawings, the auxiliary member 54 is inclined by the flange portion 16b which is integral with the secondary piston 16, but as the member for inclining the auxiliary member 54, another moving body, for example, It is also possible to use a separate body from the slave piston 16.

(Effect of device) According to this device, while the poppet 48 is inclined,
It is possible to obtain a suitable technique that employs the method of utilizing the movement of the plunger 42 side.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of an embodiment of the present invention, and FIG.
The drawing is a sectional view showing another state of the same embodiment, and FIG. 3 is a partial view for explaining the operation. 12 ... Cylinder hole, 16 ... Slave piston, 24 ... Main pressure chamber, 42 ... Plunger, 42e ... Valve seat, 48 ... Poppet, 52 ... Box-shaped member (extension part), 54 ... Auxiliary member, 56 ... Spring, 70 … Hydraulic control valve.

Claims (1)

[Scope of utility model registration request] 1. A main piston and a slave piston are slidably inserted into a cylinder hole, and a main pressure chamber is defined between these pistons, and a slave pressure chamber is defined between the slave piston and the bottom of the cylinder hole. Moreover, a fluid pressure control valve is attached to the discharge portion formed in communication with the main pressure chamber, and the fluid pressure control valve is a spring urged by a spring having a predetermined preload and a valve seat formed on this plunger. In a master cylinder with a hydraulic control valve having a poppet arranged opposite to, an extension portion that extends to avoid the poppet is integrally provided at the end portion of the plunger on the poppet side, and the extension portion is provided with the extension portion described above. An auxiliary member, which can project into the cylinder hole according to the movement of the plunger and is engageable with the moving body in the cylinder hole during the excessive stroke of the slave piston, is biased toward the main pressure chamber by a spring. Movably engaged, the poppet and the auxiliary member are fitted so as to be inclined according to the inclination of the auxiliary member, and the length of the auxiliary member is set in the cylinder hole when the plunger is not operated. Master cylinder with hydraulic control valve set so that it does not project.