JPH0144385Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a master cylinder/pressure reducing valve assembly, that is, the output hydraulic pressure of the master cylinder is transmitted to the rear wheel brakes via the pressure reducing valve, so that the brake hydraulic pressure of each rear wheel is transferred to the front wheels during heavy braking. This invention relates to a system that automatically reduces the braking oil pressure at a fixed ratio to obtain efficient braking even if the rear wheel load decreases due to the load shifting to the front of the vehicle body.

Conventionally, the pressure reducing valve in the above assembly is provided with a valve box that is installed in the master cylinder and communicates the inlet with the output port of the master cylinder and the outlet with the rear wheel brake, and the inside of the valve box. A pressure-receiving piston that is slid together so as to be partitioned into an input hydraulic chamber connected to the inlet and an output hydraulic chamber connected to the outlet, and has a communication hole that communicates both hydraulic chambers; A known valve is constructed of a valve element that opens and closes, a valve spring that biases the valve element toward the pressure-receiving piston, and a pressure regulating spring that biases the pressure-receiving piston away from the valve element. (See Publication No. 55-55044).

However, in the above pressure reducing valve, the valve body, valve spring, pressure receiving piston, and pressure regulating spring are built into the valve case, and the valve case is screwed onto the master cylinder. The entire valve must be replaced, which is uneconomical.

The present invention focuses on the fact that the main components that determine the pressure reduction characteristics such as the pressure reduction ratio and the pressure reduction action start pressure of the pressure reducing valve are the pressure receiving piston and the pressure regulating spring, and combines them into a unit, which is integrated into a common valve body. and the assembly which can be combined with a valve spring to improve economy when changing pressure reduction characteristics, and which prevents torsion of the valve spring as much as possible when the unit is combined with a valve body and a valve spring. The valve case is composed of a first half having an inlet and integral with the master cylinder, and a second half having an outlet and screwed onto the first half, the first half being The second half is provided with a valve body, a valve spring, and a regulating member that regulates the amount of movement of the valve body due to the expansion of the valve spring, and the second half is provided with a pressure receiving piston and a pressure regulating spring, and comes into contact with the valve body to prevent the valve body from moving. It is characterized by the formation of a contact surface that determines the gap between the piston and the pressure receiving piston.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, front and rear brakes Bf,
A double master cylinder M and first and second pressure reducing valves V 1 and V ₂ communicating with its first and second output ports are disposed in the hydraulic operating parts of Br _′ , Bf′, and Br. The input side of the pressure reducing valve _V1 is connected to the right front wheel brake Bf' via an oil path _l1 , and the output side is connected to the left rear wheel brake Br via an oil path _l2 . In addition, the input side of the second pressure reducing valve _V2 is connected to the left front wheel brake via oil passage _L3 .
Bf, and the output side is connected to the right rear wheel brake Br' via an oil path _l4 .

Since the configurations of the first and second pressure reducing valves V ₁ and V ₂ are the same, the first pressure reducing valve V ₁ will be explained.
As shown in the figure, a valve case 5 is provided in the cylinder body 1 of the master cylinder M. The valve case 2 includes a cylindrical first half body 21 that is formed integrally with the cylinder body 1 and has an inlet ₃ that communicates with the first output port _P1 thereof;
A cylindrical second half 2 ₂ has a male threaded cylindrical portion 5 screwed into the female threaded hole 4 of the first half 2 1 and has an outlet 6 communicating with the left rear wheel brake Br via an oil passage l _{2 .} Become.
7 is a sealing material clamped between the first and second halves 2 ₁ and 2 ₂ .

The male threaded cylindrical portion 5 of the second half ₂₂ has a small diameter cylinder hole 9 which has a smaller diameter than the opening 8 and communicates therewith, and the outer end wall 10 has a large diameter cylinder hole 11 which communicates with the outlet 6. A spring housing hole 13 located between both cylinder holes 9 and 11 is coaxially formed in the peripheral wall portion 12, and a spring housing hole 13 is formed coaxially with the cylinder hole 13.
The small diameter end 15 of 4 is slid into the small diameter cylinder hole 9, and the large diameter end 16 is slid into the large diameter cylinder hole 11. As a result, inside the valve box 2, the small diameter end 15 end face of the pressure receiving piston 14 and the inlet ₃ of the first half 21
The input hydraulic pressure chamber 17 between the large-diameter end 16 and the inner surface of the outer end wall 10 is divided into an input hydraulic chamber 17 and an output hydraulic chamber 18 between the large-diameter end 16 end face and the outer end wall 10 inner surface. communicated by. The input hydraulic chamber 17 is communicated with the right front wheel brake Bf' via the oil passage hole 20 and the oil passage _l1 formed in the peripheral wall of the first half body ₂₁ , and the output oil pressure chamber 18 is connected to the outlet 6 and the oil passage f. ₂ to the left rear wheel brake Br.

A pressure regulating spring 22 is compressed with a predetermined set load between the inner end wall of the spring housing hole 13 on the small diameter cylinder hole 9 side and the flange portion 21 at the inner end of the large diameter end portion 16, and normally the flange portion 21 is compressed with a predetermined set load. Due to the elastic force of the spring 22, it comes into contact with the opening end surface of the large diameter cylinder hole 11.

The input hydraulic chamber 17 accommodates a valve body 23 and a valve spring 24 that is compressed between the valve body 23 and the inner end wall on the inlet 3 side and urges the valve body 23 toward the pressure receiving piston 14 side. As clearly shown in FIG. 4, the valve body 23 is
A recess 25 that accommodates the movable end of the valve spring 24 on one end surface.
a short cylindrical portion 28 having a plurality of oil passage grooves 27 protruding from the other end surface of the disk portion 26 and extending in the generatrix direction from the intermediate portion to the end surface on the outer peripheral surface.
and a hemispherical convex portion 29 protruding from the end surface of the short cylindrical portion 28.

Normally, the end surface of the short cylindrical portion 28 of the valve body 23 comes into contact with the contact surface 30 between the opening 8 of the second half 2 ₂ and the small diameter cylinder hole 9. Valve body 23 of pressure receiving piston 14
A valve seat 31 is formed on the end face opposite to the convex portion 29, and normally the pressure receiving piston 14 is connected to the pressure regulating spring 22.
Since the valve body 23 is urged away from the valve body 23 by the elastic force of the valve body 23 , a predetermined gap determined by the abutment surface 30 exists between the valve body 23 and the valve seat 31 . The input hydraulic pressure chamber 17 and the small diameter cylinder hole 9 communicate with each other through oil passage grooves 27 of the valve body 23 .

On the inner surface of the peripheral wall of the input hydraulic chamber 17, the valve body 23
An annular groove 32 is formed between the disc portion 26 and the end surface of the opening 8 of the second half 2 ₂ , and a circlip 33 as a regulating member is fitted into the annular groove 32 . When the second half body 2 ₂ is removed from the first half body 2 ₁ , the circlip 33 comes into contact with the disc portion 26 of the valve body 23 and restricts the amount of movement of the valve body 23 due to the expansion of the valve spring 24 . It is something.

The distance S ₁ between the flange portion 21 of the pressure receiving piston 14 and the stepped stopper surface 34 of the circumferential wall of the spring housing hole 13 is longer than the gap S ₂ between the valve body 23 and the valve seat 31 . Seating on the valve seat 31 is ensured. On the other hand, the input hydraulic chamber (not shown) of the second pressure reducing valve V ₂ is connected to the left front wheel brake Bf via the oil hole 20 and oil path l ₃ , and the output hydraulic chamber (not shown) is connected to the right rear wheel via the outlet 6 and oil path l ₄ . They are respectively communicated with the wheel brakes Br'.

Next, to explain the operation of this embodiment, when the master cylinder M is actuated by depressing the brake pedal Bp to perform braking, the pressure oil sent out from the first output port _P1 is transferred to the first pressure reducing valve _V1. It is supplied to the front right wheel brake Bf' through the input hydraulic chamber 17 and oil path _l1 to operate it, and is also supplied to the left rear wheel brake Br through the input hydraulic chamber 17, output hydraulic chamber 18, and oil path _l2 . Been operating it. On the other hand, the pressure oil sent from the second output port is input to the input hydraulic chamber of the second pressure reducing valve _V2 ,
It is supplied to the left front wheel brake Bf through oil passage _l3 to operate it, and is also supplied to the right rear wheel brake Br' through the input and output hydraulic chambers and oil passage _l4 to operate it.

When the hydraulic pressure in the output hydraulic chamber reaches a predetermined value due to the increase in the output hydraulic pressure of the master cylinder M, the first
The pressure reducing action of the second pressure reducing valves V ₁ and V ₂ is started, and since the pressure reducing action is the same in both valves V ₁ and V ₂ , the first pressure reducing valve V ₁ will be explained as follows: Due to the difference in pressure receiving area between the inner end surface of the end portion 15 and the outer end surface of the large diameter end portion 16, the pressure receiving piston 1
The differential hydraulic pressure acting on the pressure regulating spring 22 pushes the pressure receiving piston 14 upward in FIG.
The valve seat 31 is brought into contact with the valve body 23 to close the communication hole 19 and cut off the output hydraulic chambers 17 and 18.

Furthermore, when the output oil pressure of the master cylinder M increases, the pressure within the input oil pressure chamber 17 increases, pushing the pressure receiving piston 14 downward. Therefore, the communication hole 19 reopens and the pressure within the output hydraulic chamber 18 increases. When this pressure reaches a certain value, the pressure receiving piston 14 operates again to close the communication hole 19 and stop the pressure from increasing. By repeating such actions, the braking oil pressure of the left rear wheel brake Br gradually increases.

On the other hand, since the output oil pressure of the master cylinder M directly acts on the right front wheel brake Bf', the front wheel braking oil pressure increases rapidly as the output oil pressure of the master cylinder M increases.

The left front wheel brake Bf and the right rear wheel brake Br' are similarly controlled by the second pressure reducing valve _V2 , so that when braking is applied strongly, the load on the side where the forward load of the vehicle body is large and the downward load increases is controlled by the second pressure reducing valve V2. Apply strong front brakes Bf and Bf′ to both front wheels, and apply rear brakes Br and Bf′ to both rear wheels on the side where the load is reduced.
Since Br' is operated weakly, efficient braking can be performed without causing skids in each wheel.

In the first and second pressure reducing valves V ₁ and V ₂ , their pressure reducing action start pressure is determined by the set load of the pressure regulating spring 22 , and the pressure reducing ratio is determined between the small diameter end 15 and the large diameter end 16 of the pressure receiving piston 14 . It is determined by the ratio of both cross-sectional areas.

When changing the depressurizing characteristics such as the depressurizing start pressure and the depressurizing ratio, a pressure receiving piston having a predetermined cross-sectional area is attached to another second half having the same external shape as _the second half of the valve case 2. 14 and a pressure regulating spring 22 having a predetermined set load are installed in advance and replaced with the existing second half body ₂₂ , a pressure reducing valve having new pressure reducing characteristics using the valve body 23 in common can be created. is configured.

In this case, when the existing second half 2 ₂ is removed by the first half 2 ₁ , the valve body 23 will come into contact with the circlip 33 , so there is no chance of the valve body 23 and valve spring 24 falling and getting damaged or lost. No problems will occur.

Further, for example, if the valve body 23 is configured to be suspended by the valve spring 24 without the circlip 33, when the second half 2 ₂ is removed from the first half 2 ₁ , the valve body 23 is suspended from the valve spring 24 . hangs down for a long time due to the elongation of the second half 2 2 , so that when the new second half 2 ₂ is screwed onto the first half 2 ₁ , the abutment surface 30 of the second half 2 ₂ is from the beginning.
comes into contact with the end surface of the short cylindrical portion 28 of the valve body 23 and the valve body 2
3 is rotated by friction, whereby the valve spring 24 is twisted via the valve body 23. In the present invention, since the amount of movement of the valve body 23 is restricted by the circlip 33, when the second half ₂₂ is almost completely screwed onto the first half ₂₁ , the second half 22
It is possible to bring the contact surface 30 of No. ₂ into contact with the valve body 23, thereby reducing the rotation of the valve body 23 and preventing twisting of the valve spring 24 as much as possible.

Further, the contact surface 30 of the second half body 2 ₂ causes the valve body 2 to
3 and the valve seat 31 in the pressure receiving piston 14
Since S ₂ is determined, the dimensional accuracy of the gap S ₂ is ensured, and even if the seal material 7 is interposed between the first and second halves 2 ₁ and 2 ₂ , the change in the thickness of the seal material 7 will be the same as described above. It does not affect the gap _S2 in any way.

As described above, according to the present invention, a pressure reducing valve can be constructed by screwing the second half body incorporating the pressure receiving piston and the pressure regulating spring to the first half body equipped with the valve body and the valve spring. Therefore, by simply replacing the second half, you can easily obtain a new pressure reducing valve that uses the same valve body and valve spring and has different pressure reducing characteristics, instead of replacing the entire pressure reducing valve like in the past. The economical efficiency can be greatly improved compared to the case where

Furthermore, when the second half is removed from the first half, the valve body comes into contact with the regulating member and the valve body and valve spring are removed from the first half.
Since the valve body is held in half, there is no possibility of the valve body being damaged by dropping it, or problems such as losing the valve body and valve spring.

Furthermore, the amount of movement of the valve body is restricted by the regulating member, so that the contact surface of the second half body can be brought into contact with the valve body when the screwing of the second half body to the first half body is almost completed. This makes it possible to reduce the rotation of the valve body and prevent twisting of the valve spring as much as possible.

Furthermore, by bringing the valve body into contact with the contact surface of the second half, the dimensional accuracy of the gap between the valve body and the pressure receiving piston can be ensured, and the pressure reduction starting point can be obtained with high precision. Furthermore, since the second half does not have a valve body or valve spring installed, there is no need to remove or install the valve body when inspecting or servicing the pressure receiving piston or pressure regulating spring. inspection and maintenance can be carried out easily.

[Brief explanation of the drawing]

Figures 1 to 4 show one embodiment of the present invention, in which Figure 1 is a two-system hydraulic circuit diagram of an automobile braking system, Figure 2 is a side view of the master cylinder/pressure reducing valve assembly, and Figure 2 is a side view of the master cylinder/pressure reducing valve assembly. 3 is a sectional view taken along the line shown in FIG. 2, and FIG. 4 is a perspective view of the valve body. Br, Br'...Rear wheel brake, M...Master cylinder, _P1 ...1st output port, _V1 , _V2 ...1st,
Second pressure reducing valve, 2... Valve box, 2 ₁ , 2 ₂ ... First and second halves, 3... Inlet, 6... Outlet, 14... Pressure receiving piston, 17... Input hydraulic chamber, 18 ...Output hydraulic chamber, 19...Communication hole, 22...Pressure adjustment spring, 23
... Valve body, 24 ... Valve spring, 30 ... Contact surface, 3
3...Circlip as a regulating member.

Claims (1)

[Scope of utility model registration request] An assembly of a master cylinder and a pressure reducing valve capable of reducing the pressure and transmitting the output hydraulic pressure thereof to the rear wheel brake, the pressure reducing valve being provided in the master cylinder and having an inlet connected to an output port of the master cylinder. , and a valve case having an outlet communicating with the rear wheel brake, and a valve case fitted in the valve case so as to divide the inside thereof into an input hydraulic chamber connected to the inlet and an output hydraulic chamber connected to the outlet. a pressure-receiving piston having a communication hole that communicates both hydraulic chambers; a valve body that is disposed within the input hydraulic chamber and opens and closes the communication hole during pressure reduction; and a valve body that biases the valve body toward the pressure-receiving piston. A valve spring configured with a pressure regulating spring that biases the pressure receiving piston in a direction away from the valve body, wherein the valve box includes a first half body having the inlet and integral with the master cylinder; a second half having the outlet and screwed onto the first half, the first half having the valve body, the valve spring, and the amount of movement of the valve body due to extension of the valve spring; a regulating member is provided for regulating the pressure receiving piston, and the second half body is provided with the pressure receiving piston and the pressure regulating spring, and forms a contact surface that comes into contact with the valve body and determines a gap between the valve body and the pressure receiving piston. A master cylinder/pressure reducing valve assembly characterized by: