JPH0150621B2 - - Google Patents

Description

[Detailed Description of the Invention] According to the present invention, when the output hydraulic pressure of the master cylinder transmitted to the rear wheel brake exceeds a predetermined value, the output hydraulic pressure is reduced at a fixed ratio and transmitted to the rear wheel brake. , a brake hydraulic control device for a vehicle, in particular, a housing is interposed in a flow path connecting an output port of a master cylinder and a hydraulic operating part of a rear wheel brake, and a pressure receiving piston is slid into a cylinder hole in the housing. , on one end side of this pressure receiving piston,
An input hydraulic chamber communicating with the upstream side of the flow path and an output hydraulic chamber communicating with the downstream side of the flow path are formed at the other end, and the pressure receiving area on the output hydraulic chamber side of the pressure receiving piston is defined as the input hydraulic chamber. A valve is connected between the input and output hydraulic chambers by a valve that opens when the pressure receiving piston slides toward the output hydraulic chamber and closes when the piston slides toward the input hydraulic chamber. The present invention relates to a pressure regulating spring that communicates with the pressure receiving piston and urges the pressure receiving piston toward its sliding limit toward the output hydraulic pressure chamber.

Conventionally, in such braking hydraulic control devices, the sliding limit of the pressure receiving piston toward the output hydraulic chamber side was regulated by the contact between the tip of the pressure receiving piston and the end wall of the output hydraulic chamber. In some cases, when the pressure receiving piston returns to the sliding limit due to the elastic force of the pressure regulating spring when the brake is released, its tip and the end wall of the output hydraulic chamber may come into impact and make a collision noise. However, there is a drawback that the operating characteristics of the pressure receiving piston may change to some extent due to the adsorption phenomenon of the pressure receiving piston to the end wall of the output hydraulic chamber.

It is an object of the present invention to provide a simple and effective braking hydraulic control device free from such drawbacks, in which one end of the pressure receiving piston is provided in the housing, separated from the input and output hydraulic chambers. The spring chamber accommodates the pressure regulating spring that urges the pressure receiving piston via a washer, and also contacts the washer to direct the pressure receiving piston to the output hydraulic chamber side. The present invention is characterized in that it includes a stopper that regulates the sliding limit, and a buffer member that comes into cushioning contact with the washer to alleviate the impact of contact between the washer and the stopper.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, front and rear wheel brakes Bf, Br' and
Mutually independent first and second flow paths L ₁ and L ₂ extending from the output side of the dual master cylinder M are connected to the hydraulic actuating parts of Bf' and Br, respectively, and these flow paths
A brake hydraulic control device C of the present invention is provided between L ₁ and L ₂ and the rear wheel brakes Br and Br'.

The above master cylinder M and brake hydraulic control device C
will be explained in detail with reference to FIGS. 2 to 4.

First, the double master cylinder M is configured in a tandem type, and when the brake pedal 1 is operated, a pair of front and rear pistons 2 ₁ and 2 ₂ in the cylinder are connected to the first and second output ports P ₁ and P ₂ respectively. Pressure oil can be supplied from the flow path to the first and second flow paths L ₁ and L ₂ . This pressure oil is led to the front wheel brakes Bf, Bf' and the brake hydraulic control device C.

The brake hydraulic control device C is configured symmetrically, and its left and right housings 3 ₁ and 3 ₂ are joined to each other by bolts 5 and nuts 6 via flanges 4 ₁ and 4 ₂ . In the housings 3 ₁ and 3 ₂ ,
Cylinder holes 7 ₁ , 7 ₂ and a larger diameter hole 8
₁ , 8 ₂ are formed, and each cylinder hole 7 ₁ ,
Pressure-receiving pistons 9 ₁ and 9 ₂ having the same diameter are slid into each other on 7 ₂ , and a minimum distance necessary for the operation of each pressure-receiving piston is provided between the pressure-receiving pistons 9 ₁ and 9 ₂ . Small cylinder holes 10 ₁ , 10 ₂ of the same diameter are formed in each pressure receiving piston 9 ₁ , 9 ₂ .
These small cylinder holes 10 ₁ , 10 ₂ have valve moving pistons 11 ₁ , 1 whose back surfaces abut each other.
1 _{and 2} are in sliding contact with each other.

The large-diameter holes 8 ₁ , 8 ₂ communicate with each other to form one spring chamber 8 , and in this spring chamber 8 , a shoulder 31 ₁ faces the outer periphery of the axially intermediate portion of both the pressure receiving pistons 9 ₁ , 9 ₂ . , 31 ₂ are formed, and these shoulders 31 ₁ ,
Washers 32 ₁ and 32 ₂ that are in contact with them between 31 ₂
A common relatively strong coiled pressure regulating spring 12
will be reduced.

Further, between the two valve moving pistons 11 ₁ and 11 ₂ , shoulder portions 13 ₁ and 13 ₂ of each piston 11 ₁ and 11 ₂ are provided.
and the inner and outer shoulder portions 1 of the small cylinder holes 10 ₁ and 10 ₂
A relatively weak coil-shaped positioning spring 17 is compressed through washers 16 ₁ and 16 ₂ that can abut on _{4 1} and 14 ₂ and 15 1 and 15 ₂ , respectively.

First and second input hydraulic chambers 18 ₁ , 18 ₂ are connected to the outer ends of the valve moving pistons 11 ₁ , 11 ₂ in both small cylinder holes 10 ₁ , 10 ₂ , and both cylinder holes 7 ₁ , 7 ₂ includes pressure receiving pistons 9 ₁ , 9 ₂
The first and second output hydraulic chambers 19 ₁ ,
19 ₂ are respectively defined, and these first and second input hydraulic chambers 18 ₁ , 18 ₂ have inflow ports 20 ₁ ,
Upstream of the first and second flow paths L ₁ , L ₂ via 20 ₂ are also connected to the first and second output hydraulic chambers 19 ₁ , 1
9 ₂ has _a flow path _{L 1 ,}
The downstream ends of L ₂ are connected so that they are in constant communication.

The end walls of the small cylinder holes 10 ₁ and 10 ₂ are provided between adjacent input and output hydraulic chambers 18 ₁ and 19 ₁ and between the adjacent input and output hydraulic chambers 18 1 and 18 ₂ , 1
Communication holes 22 ₁ , 22 ₂ are provided to communicate between the valve opening rods _{24 1} , ₂₄ , which project from the outer ends of the valves _{23 1 ,} 23 ₂ , respectively. ₂ can penetrate. Each valve 23 ₁ , 23 ₂ and valve moving piston 11 ₁ ,
Closing springs _{25 1 and} 25 ₂ are respectively compressed between the valves 11 and 11 2 , and normally the opening rods 24 ₁ and 24 ₂ of the valves 23 ₁ and 23 ₂ are connected to the end walls of the cylinder holes 7 ₁ and 7 ₂ . The valves 23 ₁ and 23 ₂ are held in the open position at the outward sliding limit of each pressure receiving piston 9 ₁ and 9 ₂ . When the pressure receiving pistons 9 ₁ , 9 ₂ move inward and the end walls of the small cylinder holes 10 ₁ , 10 ₂ come into contact with the valves 23 ₁ , 23 ₂ , the communication holes 22 1 , 23 ₂ come into contact with each other.
22 ₂ is occluded.

In order to obtain the above-mentioned outward sliding limit of each pressure receiving piston 9 ₁ , 9 ₂ , annular stoppers 34 ₁ , 34 ₂ are formed on both end walls of the spring chamber 8 , and the washers 32 1 , 32 2 are attached to these annular stoppers 34 ₁ , 34 ₂ . They are starting to touch each other.
Further, stoppers 34 ₁ , 3 are provided on both end walls of the spring chamber 8.
Annular grooves 35 ₁ and 35 ₂ are formed adjacent to 4 ₂ ,
_An annular buffer _{member 36 1 ,}
36 ₂ is fitted. Each of _the buffer members _{36 1} , 36 ₂ is made of an elastic material such as rubber or synthetic resin, and as shown in FIGS. A plurality of protrusions 37 that protrude further and can come into contact with the washers 32 ₁ and 32 ₂ are integrally provided, and recesses 38 and 39 are provided around each protrusion 37 and on its back side. The protrusion 37 has elasticity that can be compressed and deformed by the elastic force of the pressure adjustment spring 12, and the elastic force of the pressure adjustment spring 12 causes the washers 32 ₁ and 32 ₂ to come into contact with the stoppers 34 ₁ and 34 ₂ . In the contact state, the recesses 38, 39
It has become buried within.

In order to ensure the contact between the washers 32 ₁ , 32 ₂ and the stoppers 34 ₁ , 34 ₂ , pressure receiving pistons 9 ₁ , 9 ₂ are provided.
A gap s is provided between the outer end of the output hydraulic pressure chambers 19 ₁ and the end walls of the output hydraulic chambers 19 1 and 19 ₂ .

Connectors 26 ₁ and 26 ₂ are attached to the inner ends of each valve 23 ₁ and 23 ₂ , respectively. The inner ends of these connectors 26 ₁ , 26 ₂ are connected to stoppers provided at the outer ends of the valve moving pistons 11 ₁ , 11 ₂ when the pistons 11 ₁ , 11 ₂ move inward by a predetermined distance l ₂ . 27 ₁ and 27 ₂ . This distance l ₂ is equal to the distance between the valves 23 ₁ ,
The distance l 1 that the pressure receiving pistons 9 ₁ , 9 ₂ move from the valve opening position to the valve closing position of 23 ₂ is greater than the distance l ₁ and the washers 16 1 , ₁₆ with respect to this distance l ₁ and the small cylinder holes 10 ₁ , 10 ₂ . ₂ is smaller than the sum of the possible distance l and ₃ .

A small hole 28 communicating with the outside is provided at the joint between the housings 3 ₁ and 3 ₂ , and a seal ring 29 is provided inside this joint to prevent dust from entering from the outside. . This seal ring 29 allows hydraulic oil etc. to flow from the inside to the outside, and seal members 30 ₁ , 30 ₂ between the pressure receiving pistons 9 ₁ , 9 ₂ and the cylinder holes ₇ 1 , 7 _{2 .}
If the hydraulic oil leaks into the large-diameter holes 8 ₁ and 8 ₂ due to wear and damage, the hydraulic oil will flow out through the seal ring 29 and the small hole 28, and the failure will be solved by removing the oil in the reservoir of the master cylinder M. This makes it possible to detect abnormal surface deterioration.

Next, the operation of this embodiment will be explained.
When the master cylinder M is not in operation, both the left and right pressure receiving pistons 9 ₁ and 9 ₂ are pressed to the outward sliding limit shown in the figure by the spring force of the pressure regulating spring 12 and the positioning spring 17, and the valves 23 ₁ and 23 ₂ are The valves are open, and the first and second input and output hydraulic chambers 18 ₁ , 1
9 ₁ and 18 ₂ and 19 ₂ are in communication. Therefore, when the brake pedal 1 is operated here, the output hydraulic pressure of the master cylinder M is transmitted to each downstream of the first and second flow paths L ₁ and L ₂ , and
Rear wheel brakes Bf, Bf' and Br, Br' operate simultaneously.

Then, as the output oil pressure of the master cylinder M increases, the first and second input and output oil pressure chambers 18 ₁ , 19 ₁
The pressure inside the pressure receiving pistons 9 ₁ , 19 ₂ also rises, but when the pressure reaches a certain value, the difference in the pressure receiving areas between the inner and outer ends of the pressure receiving pistons 9 ₁ , 9 _{2 increases} .
The differential hydraulic pressure acting on the pressure regulating _{spring 12} and the positioning spring 17 becomes larger than the set load of the pressure regulating spring 12 and the positioning spring 17, and the pressure receiving pistons ₉₁ and ₉₂ slide inward while compressing the pressure regulating spring 12 and the positioning spring 17, respectively. move. On the other hand, at this time, each valve moving piston 11 ₁ , 11 ₂
Since approximately equal oil pressure is applied to the outer ends of the pistons 11 ₁ and 11 2 , the springs 25 ₁ and ₂ close the valves 23 ₁ and 23 ₂ without moving.
5 ₂ to keep the valve opening rods 24 ₁ , 24 ₂ in contact with the end walls of the cylinder holes 7 ₁ , 7 ₂ . Therefore, when each pressure receiving piston 9 ₁ , 9 ₂ moves inward by a distance l ₁ , the valves 23 ₁ , 2
3 ₂ closes the communication holes 22 ₁ and 22 ₂ . During this period, the braking oil pressure for the rear wheels does not increase.

When the output hydraulic pressure of the master cylinder M further increases, the pressure within the input hydraulic chambers 18 ₁ and 18 ₂ increases, pushing each pressure receiving piston 9 ₁ and 9 ₂ outward.
Therefore, the valves 23 ₁ , 23 ₂ open again, increasing the pressure in the output hydraulic chambers 19 ₁ , 19 ₂ . When this pressure reaches a certain value, the pressure receiving piston 9 ₁ ,
9 ₂ is activated again, the communication holes 22 ₁ and 22 ₂ are closed, and the increase in pressure is stopped. By repeating these actions, the braking oil pressure for each rear wheel gradually increases.

On the other hand, since the output hydraulic pressure of the master cylinder M directly acts on the front wheel brakes Bf, Bf', the front wheel braking hydraulic pressure increases rapidly as the output hydraulic pressure of the master cylinder M increases. In this way, when braking is applied strongly, the front wheel brakes Bf and Bf' are applied more strongly to the front wheel on the side where the vehicle body leans forward and the downward load increases.
Rear brake for the rear wheel on the side where the load is reduced
Since Br and Br' are operated weakly, efficient braking can be performed without causing skids in each wheel.

When the braking is released, the pressure receiving pistons 9 ₁ , 9 ₂ are slid outward by the elastic force of the pressure regulating spring 12 , and when they approach their sliding limits, the washers 32 ₁ , 32 ₂ first
gives compressive deformation to each protrusion 37 of the buffer members 36 ₁ , 36 ₂ to relieve the impact force of the pressure receiving pistons 9 ₁ , 9 ₂ , and then the washers 32 ₁ , 32 ₂ compress the stoppers 34 1 , 36 ₂ .
34 ₂ relatively quietly, no collision noise is generated, or even if it occurs, it is extremely small. When the washers 32 ₁ , 32 ₂ come into contact with the stoppers 34 ₁ , 34 ₂ , the compressive deformation of the buffer members 36 ₁ , 36 ₂ does not proceed any further, so that excessive deformation of the members 36 ₁ , 36 ₂ is prevented. .

Next, one of the systems in the brake hydraulic circuit, for example the second flow path _L2 side, breaks down and the rear wheel brake
Suppose that braking hydraulic pressure is no longer applied to the hydraulic operating part of Br′. At this time, when the brake pedal 1 is operated, the output oil pressure of the master cylinder M is changed to the first flow path _L1.
The pressure in the first input hydraulic pressure chamber 18 ₁ increases, but the pressure in the second input hydraulic pressure chamber 18 ₂ does not increase. Therefore, both the valve moving pistons 11 ₁ and 11 ₂ move rightward in the figure, and the washer 16 ₁ engages with the inner shoulder 14 ₁ of the small cylinder hole 10 ₁ . Then, the valve moving piston 11 ₁ moves the pressure receiving piston 9 ₁ inward. When the valve moving piston ₁₁₁ moves by a predetermined distance _l2 ,
The stopper 27 ₁ at its outer end engages the inner end of the connector 26 ₁ and moves the valve 23 ₁ inwardly. Since the distance l ₂ is smaller than l ₁ +l ₃ , the valve 23 ₁ is separated from the end wall of the small cylinder hole 10 ₁ during this period and maintains its open state. In this way, the valve moving piston 11 ₁ , the pressure receiving piston 9 ₁ , and the valve 23 ₁ move inward to a position where the inner end of the pressure receiving piston 9 ₁ abuts the inner end of the other pressure receiving piston 9 ₂ .

When the pressure receiving pistons 9 ₁ and 9 ₂ are in contact with each other, the valve moving piston 11 ₁ is pressed inward by the hydraulic pressure in the first input hydraulic pressure chamber 18 ₁ .
Washer 16 ₁ is inside shoulder _{14 1} of small cylinder hole 10 1
The stopper 27 ₁ of the valve moving piston 11 ₁ remains engaged with the inner end of the connector 26 ₁ . Therefore, at this time, the valve 23 ₁ opens the communication hole 22 ₁ . As a result, the output hydraulic pressure of the master cylinder M is directly transmitted to the first output hydraulic chamber ₁₉₁ , and the front and rear wheel brakes Bf' and Br of the first flow path _L1 operate with the same strength. That is, this brake hydraulic control device C is provided with a bypass function.

In addition, in the above embodiment, the valve moving pistons 11 ₁ and 11 ₂ are configured as separate bodies, but
If there is no problem with machining accuracy, this can be integrated.

As described above, according to the present invention, the housing includes
A spring chamber is formed that is separated from the input and output hydraulic chambers and receives one end of the pressure receiving piston, and this spring chamber houses a pressure regulating spring that springs the pressure receiving piston via a washer, and is in contact with the washer. A stopper that restricts the sliding limit of the pressure receiving piston toward the output hydraulic chamber side, and a buffer member that comes into cushioning contact with the washer to reduce the impact of contact between the washer and the stopper are provided. Even when the pressure receiving piston rapidly returns to its sliding limit toward the output hydraulic pressure chamber side due to the elastic force of the pressure regulating spring upon release, the collision sound between the washer and the stopper is prevented by the buffering action of the buffer member, or can be significantly reduced.

In addition, since a stopper for the pressure receiving piston is provided in the spring chamber, a gap is inevitably formed between the pressure receiving piston and the end wall of the output hydraulic chamber, which causes the pressure receiving piston to stick to the end wall of the output hydraulic chamber. is gone,
The operation of the pressure receiving piston can be stabilized.

Further, since the spring chamber is normally designed to prevent hydraulic oil from entering, the buffer member can be obtained at low cost without considering oil resistance, and furthermore, the amount of compressive deformation is regulated by the stopper. Because of this, it exhibits high durability.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a braking system for an automobile equipped with the device of the present invention, Fig. 2 is a longitudinal cross-sectional plan view of essential parts showing an embodiment of the device of the present invention, and Figs. FIG. 3 is a front view and a vertical side view of the member. Br, Br'... Rear wheel brake, C... Braking hydraulic control device, L ₁ , L ₂ ... First and second flow paths, M... Master cylinder, 9 ₁ , 9 ₂ ... Pressure receiving piston, 12
...Pressure regulating spring, 18 ₁ , 18 ₂ ...Input hydraulic chamber, 1
9 ₁ , 19 ₂ ... Output hydraulic chamber, 23 ₁ , 23 ₂ ... Valve, 32 ₁ , 32 ₂ ... Washer, 34 ₁ , 34 ₂ ...
Stoppers, 36 ₁ , 36 ₂ ...buffer members.

Claims (1)

[Claims] 1. A housing is interposed in the flow path connecting the output port of the master cylinder and the hydraulic operating part of the rear wheel brake, and a pressure receiving piston is slid into the cylinder hole in the housing, and one end of the pressure receiving piston is provided with a housing.
An input hydraulic chamber communicating with the upstream side of the flow path and an output hydraulic chamber communicating with the downstream side of the flow path are formed at the other end, and the pressure receiving area on the output hydraulic chamber side of the pressure receiving piston is defined as the input hydraulic chamber. A valve is connected between the input and output hydraulic chambers by a valve that opens when the pressure receiving piston slides toward the output hydraulic chamber and closes when the piston slides toward the input hydraulic chamber. A pressure regulating spring that communicates with the pressure receiving piston toward its sliding limit toward the output hydraulic pressure chamber is provided, wherein one end portion of the pressure receiving piston is provided in the housing and is isolated from the input and output hydraulic pressure chambers. forming a spring chamber that receives the pressure, and accommodating the pressure regulating spring that urges the pressure receiving piston via a washer in the spring chamber;
a stopper that comes into contact with the washer to limit the sliding limit of the pressure receiving piston toward the output hydraulic chamber; and a buffer member that comes into cushioning contact with the washer to reduce the impact of contact between the washer and the stopper. A braking hydraulic control device for a vehicle, characterized in that it is provided with: