JPS6194863A - Damping liquid pressure control device - Google Patents

Abstract

PURPOSE:To reduce the size of this marked device and make its damping force proper by perforating holes with large and small diameters on both ends of a piston that controls a pressure reduction start point, fitting a plunger in the large diameter hole and a stem with an exit path in the small diameter hole so as to separately be slided, and sharing each spring of the plunger and the piston. CONSTITUTION:A circular hole 5a with large diameter and a circular hole 5c are perforated at the plug 3 side of a piston 5 and its reverse side, respectively. The large diameter section 6a of a stepped plunger 6 is fit in the circular hole 5a so as to freely be slided. In addition, a stem 4 with an exit path 4a is fit in the circular hole 5c so as to freely be slided. Furthermore, a spring 10 is elastically provided between the large diameter hole 3a bottom 3d of the plug 3 and a retainer 9 arranged at the plunger 6 stepped section 6c and the plunger 6 is always energized to the piston 5 side. Besides, the energizing force of the spring 10 is varied by guiding the control liquid pressure corresponding to loaded load to a chamber 12, moving the piston 5 left, and bending the spring 10.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a brake fluid pressure control device, and more particularly to a brake fluid pressure control device that obtains an appropriate rear wheel control force depending on the loading condition of a vehicle. be.

[Conventional technology]

Proportioning pulp applies the same braking force to the front and rear wheels when the braking force is low at the beginning of braking, and when the braking force exceeds a predetermined value, the braking force on the rear wheel side is made smaller than the braking force on the front wheel side. This prevents the rear wheels from locking up. A plunger that responds to mask cylinder pressure opens and closes the pulp, and when the pulp opens and closes, the mask cylinder pressure is reduced at a predetermined rate and transmitted to the rear wheel cylinder. I try to do that. In order to apply appropriate rear wheel braking force to this proportioning pulp according to the loading condition of the vehicle, the decompression action starting point, that is, the point at which the depressurization action that reduces the output hydraulic pressure relative to the input hydraulic pressure starts. A brake hydraulic pressure control device that changes the brake fluid pressure has been proposed in the past (Japanese Patent Application Laid-Open No. 167855/1983).

Conventional devices such as those described above generally use a control piston that receives hydraulic pressure to change the force of a spring that is set in a plunger and determines the starting point of the decompression action9.
A piston spring was required to hold the control piston in an inactive position.

[Problem that the invention seeks to solve]

Therefore, since the plunger spring, the piston spring, the piston, the plunger, etc. are arranged in series, the shape becomes large, and the starting point of the operation is unstable when the vehicle is empty and when the vehicle is loaded.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is possible to use the spring for setting the plunger and the spring for setting the piston, thereby reducing the size of the device, and also improving the starting point of the depressurization action when the car is empty or loaded. The purpose is to stabilize and always obtain appropriate braking force.

[Means for solving problems]

In the brake hydraulic pressure control device according to the present invention, holes are formed on both end surfaces of the control piston, and the large pressure receiving surface side of the plunger is slidably fitted into one of the holes, and the main body is fitted into the other hole. A stem that is fixed and has an exit passage is slidably fitted therein, and the inner diameter of the hole into which the granger is fitted is set larger than the inner diameter of the other hole.

[Effect]

In this invention, when no control hydraulic pressure is applied to the piston, the piston is always held in the non-operating position by the output hydraulic pressure acting on both holes, so the spring for the plunger and the spring for the piston are shared. can do.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

The figure is a vertical cross-sectional view showing a brake hydraulic pressure control device according to an embodiment of the present invention, and (1) is a stepped hole (2) formed inside.
.

It has a roughly cylindrical body with a large diameter hole (
A plug (3) is fixed within 2a). This plug (3) has a large diameter hole (3) inserted into the main body (1).
a) An entrance hole (3b) connected to a mask cylinder (not shown) is formed on the outside side, and both of these holes (3a).

(3b) are communicated through a small diameter hole (6c).

Further, in the small diameter hole (2b) at the other end of the main body (1), there is an outlet passage (4a) connected to a wheel cylinder (not shown).
) is attached to the stem (4).

A control piston ( 5
) are slidably fitted in a fluid-tight manner. A circular hole (5a) is formed on the plug (8) side of this piston (5), and a stepped plunger (6) is inserted into this hole (5a).
The large-diameter portion (6a) is slidably fitted. The small diameter portion (6b) of the stepped plunger (6) projects into the inlet hole (6b) from the small diameter hole (6C) of the plug (3). The large diameter portion (6a) and small diameter portion (6b) of this plunger (6) are held liquid-tight with respect to the piston (5) and plug (8) via seal members (γ) and (8). . The bottom surface (6d) of the large diameter hole (6a) of the plug (3)
) and a retainer (9) disposed on the stepped portion (6C) of the plunger (6), a spring (101) is loaded to constantly urge the plunger (6) toward the piston (5).

Therefore, when the plunger (6) is not activated,
The end surface (6d) of the large diameter portion (6a) of the plunger (6) is in contact with the bottom surface (5b) of the hole (5a) of the piston (5), and at this time, the large diameter portion (6a) of the plunger (6) It is slightly exposed from the hole (5a) of the piston (5). Therefore, the force of the spring αQ acts on the piston (5) via the plunger (6), and this piston (5)
It comes into contact with the stepped portion (2d) and stops.

Further, a circular hole (5C) is formed on the stem (4) side end surface of the piston (5) so that the axis coincides with the circular hole (5a), and the inner side end (4b) of the stem (4) This hole (5C)
These pistons (5) are slidably fitted within the piston (5).
The seal member aη also maintains liquid tightness between the stem (4) and the stem (4). Two holes (
5a) and (5c) are communicated with a plurality of passages (5d) surrounding the axis, and the inner diameter (d) of the hole (5a) on the plunger (6) side is the same as that on the stem (4) side. Hole (5C)
The inner diameter (d2) 9 is also set large. Therefore,
Since the output hydraulic pressure acts on both holes (5a) and (5C) having different cross-sectional areas, the piston (5) is always urged toward the stem (4).

In addition, a space (
(2) is an indication pressure chamber into which control hydraulic pressure from the outside is introduced via passage (4C), and control hydraulic pressure corresponding to the vehicle's carrying load is introduced into this chamber (12). Piston (6
) to the left, and by bending the spring (10) via the Eli plunger (6), the spring (1
It is possible to change the biasing force of the plunger (6) of the plunger (6).

A valve mechanism (13) is attached to the large diameter end of the plunger (6).
) are accommodated. This valve mechanism 0■ consists of a valve spring μs) that biases the valve body ← → the newly constructed valve body O→
), the plunger (6) is fixed to the spring αQ and the piston (6)
When the valve body (14) is in elastic contact with the bottom of the hole (5a)
When the valve body (141) is pushed up by the rod (14a) to open the passage (6e) in the plunger (6) and the plunger (6) moves toward its small diameter portion (6b) (to the left in the figure), The valve body 0 → is seated on the valve seat 06) and the passage (
6e).

The operation of the device having the above configuration will be explained.

Brake fluid pressure from the mask cylinder is supplied through the inlet hole (3b)
From the passage of the plunger (6) (6e valve mechanism (1B)
, the passage (5d) of the piston (5) or the hole (5C) of the piston (5), and the outlet passage (4a) formed in the stem (4).
), etc., to the rear wheel cylinder, and at the beginning of braking when the brake fluid pressure is low,
Plunger (o) U does not operate and the hydraulic pressure in the mask cylinder is directly guided to the wheel cylinder.

When the vehicle is empty, the control hydraulic pressure is not introduced in the direction of the indication chamber (direction), so the piston (5) is held at the position shown in the figure. If the brake hydraulic pressure increases in this state, the plunger (6) with a different pressure receiving area The plunger (6) is moved to the left against the spring (10) by the hydraulic pressure acting on both end faces of the valve.As a result, the valve body Q→ is seated on the valve seat (16) and introduced into the wheel cylinder. The increase in brake fluid pressure is stopped.

After that, when the brake fluid pressure further increases, the fluid pressure acting on the large diameter portion (6a) side end surface of the plunger (6) does not increase, so the fluid pressure acting on the small diameter portion (6b) side increases, causing the plunger (6) ) is moved to the right, and the valve mechanism α is opened. Then, the hydraulic pressure acting on the large diameter portion (6a) increases, and the plunger (6) moves to the left again to close the valve mechanism 09). In this process, the plunger (6) reciprocates left and right as the brake fluid pressure increases, and depending on the difference in pressure receiving area, the brake fluid pressure introduced into the rear wheel cylinder is lower than the brake fluid pressure on the input side. Increase by increasing rate.

As described above, when the control hydraulic pressure is not introduced into the indicator royal chamber (12), even when the plunger (6) moves and separates from the piston (5), the piston (5) moves between two cylinders with different cross-sectional areas. Since the output hydraulic pressure acting on the holes (5a) and (5C) holds the piston (5) in the non-operating position shown in the figure, there is no need for a spring for holding the piston (5), which was required in the past.

On the other hand, when loading a vehicle, control hydraulic pressure from the outside is introduced into the indicated pressure chamber (whitening) depending on the loading state to move the piston (5) to the left.As the piston (5) moves to the left, the plunger (6) is also moved to the left, compressing the spring αO).

As a result, the force with which the spring force urges the plunger (6) to the right in the figure increases, and the brake fluid pressure acting on both end surfaces of the plunger (6) to move the plunger (6) to the left is as follows: This is larger than when the car is empty. In other words, the starting point for reducing the brake fluid pressure sent to the rear wheel cylinders is set higher in accordance with the load capacity of the vehicle, and an appropriate rear wheel braking force can be applied. From this state, the pressure reduction effect due to the reciprocating movement of the plunger (6) is performed in the same manner as when the vehicle is empty.

〔Effect of the invention〕

As described above, according to the present invention, when the control piston is not receiving control hydraulic pressure, it is always pressed to the non-operating position by the output hydraulic pressure. can be shared. Furthermore, the starting point of the depressurization action can be stabilized when the vehicle is empty and when the vehicle is loaded, and an appropriate braking force can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a brake hydraulic pressure control device according to an embodiment of the present invention. (1)...Body (4)...Stem (4a
)...Outlet passage (5)...Piston (5a).
... Piston plunger side hole (5C) ... Piston stem side hole (6) ... Plunger (6a) ... Plunger large pressure receiving side α0) ... Spring (13) ... Valve Mechanism', Z-1'-n''

Claims (1)

[Claims] A plunger that is biased in one direction by a spring and is moved forward and backward by input hydraulic pressure introduced into both end faces having different pressure receiving areas; a control piston that acts on the spring by being moved by control hydraulic pressure introduced to one end surface and changes the biasing force of the spring against the plunger. In the brake fluid pressure control device,
Holes are formed on both end surfaces of the control piston, the large pressure receiving surface side of the plunger is slidably fitted into one of the holes, and a stem fixed to the main body and having an outlet passage is fitted into the other hole. A brake hydraulic pressure control device, characterized in that the brake fluid pressure control device is slidably fitted, and the inner diameter of the hole on the plunger side is set larger than the inner diameter of the hole on the stem side.