JPH0212782B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a dual master cylinder to
A brake hydraulic control device for a vehicle braking system comprising two independent brake hydraulic circuits, in particular a brake system that supplies hydraulic pressure lower than the front wheel brake hydraulic pressure as the rear wheel brake hydraulic pressure. This invention relates to a hydraulic control device.

Conventionally, as shown in FIG.
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 operating parts of the rear wheel brakes Bf, Br' and Bf', Br, respectively. There are some forms of this. Furthermore, two hydraulic actuating parts are provided for both front wheel brakes Bf, Bf', and a first and a second hydraulic actuating part are provided for both front wheel brakes Bf, Bf'.
There is also one in which both flow paths L ₁ and L ₂ are connected. In such a braking device,
During heavy braking, each rear wheel brake hydraulic pressure is automatically reduced at a fixed ratio to the front wheel brake hydraulic pressure of the same system.
In order to obtain efficient braking even when the rear wheel load decreases due to the forward tilt of the vehicle body, the first and second flow paths L ₁ and L ₂ are connected to the rear wheel brakes Br and Br' on the way to the rear wheel brakes Br and Br'. A common brake hydraulic control device C is provided.

By the way, such a common control device C has
It is necessary to provide a bypass function so that if one system of the braking hydraulic circuit fails, the other system will strongly brake the rear wheels as well as the front wheels.

An object of the present invention is to obtain a brake hydraulic pressure control device for a vehicle braking device that has such a bypass function with a simple configuration.

In order to achieve this object, the present invention interposes a common housing in the middle of the first and second flow paths,
A pair of left and right pressure receiving pistons are slid into the cylinder holes in the housing, and first and second input hydraulic chambers are provided at the inner ends of these pressure receiving pistons, respectively communicating upstream of the first and second flow paths. In addition, first and second output hydraulic chambers are respectively formed on the outer end side to communicate with the downstream side of both flow paths, and the pressure receiving area of each output hydraulic chamber side of each pressure receiving piston is equal to the pressure receiving area of each output hydraulic chamber side of each input hydraulic chamber side. The area between each adjacent input and output hydraulic chambers is biased outward by a closing spring, and the valve opens at the outward sliding limit of each pressure receiving piston, and when sliding inward. A common first pressure regulating spring is compressed between the two pressure receiving pistons, and a valve moving piston is connected to the both pressure receiving pistons through a valve to be closed, and has both ends facing the first and second input hydraulic pressure chambers. A pair of opposing shoulders are formed at the center of the valve moving piston, and each shoulder and the adjacent inner end of each of the pressure receiving pistons come into contact with each other so as to be able to separate from each other. A pair of washers are provided, a common second pressure regulating spring weaker than the first pressure regulating spring is compressed between the two washers, and the valve moving piston and the valve are mutually connected with a predetermined play in the axial direction. and opens the valve on the opposite side to the direction of movement when the valve moving piston moves a predetermined distance or more from the neutral position according to the pressure difference between the first and second input hydraulic chambers. It is characterized by what it did.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, the dual master cylinder M is configured in a tandem type. ₁ and ₂ are the first and second output ports, respectively.
Pressure oil can be supplied from P ₁ and P ₂ 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 slidably connected to each other on 7 ₂ . Small cylinder holes 10 ₁ , 10 ₂ having the same diameter are formed in each pressure receiving piston 9 ₁ , 9 ₂ , and these small cylinder holes 10 ₁ , 10 ₂ have
Valve moving pistons 11 whose backs abut each other
₁ and 11 ₂ are in sliding contact with each other. A common strong first pressure regulating spring 12 is compressed between both the pressure receiving pistons 9 ₁ , 9 ₂ , and both valve moving pistons 11 ₁ ,
Between 11 ₂ is the shoulder 1 of each piston 11 ₁ and 11 ₂ .
_{A relatively weak _ _ _ _ _ _ _} One second pressure regulating spring 17 is compressed.

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 both flow paths via outflow ports 21 ₁ and 21 ₂
The downstream sides of L ₁ and L ₂ are connected so that they are always in communication with each other.

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.

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 is leaked to the outside through the seal ring 28 and the small hole 28, and the failure is detected as an 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 , 9 ₂ are pressed to the outward sliding limit shown in the figure by the set loads of the first and second pressure regulating springs 12 , 17 , and the valves 23 ₁ , 23 ₂ 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. At this time, piston 2 of master cylinder M
Even if a slight pressure difference occurs between _the first and second input hydraulic chambers 18 1 and 18 ₂ due to a difference in the operating timing of the input hydraulic pressure chambers ₁ and ₂ , the second pressure regulating spring 17 and the left and right washers 16
Valve movement piston 11 ₁ , by cooperation of ₁ , 16 ₂
11 ₂ can continue to be held in a predetermined neutral position.

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 oil pressure acting on 9 ₂ becomes larger than the set load of the first and second pressure regulating springs 12 and 17, and the pressure receiving pistons 9 ₁ and 9 ₂ move inward while compressing the pressure regulating springs 12 and 17, respectively. Slide. On the other hand, at this time, approximately equal oil pressure is applied to the outer ends of each valve moving piston 11 ₁ , 11 ₂ , so these pistons 1
1 ₁ and 11 ₂ do not move, and each valve 23
₁ , 23 ₂ are pressed outward by the closing springs 25 ₁ , 25 ₂ , and the valve opening rods 24 ₁ , 24 ₂ close the cylinder holes 7 ₁ , 7 _{2 .}
maintain the state in contact with the end wall of the Therefore,
When each pressure receiving piston 9 ₁ , 9 ₂ moves inward by a distance l ₁ , the valves 23 ₁ , 23 ₂ are connected to the communication holes 22 1 , 23 ₂ .
Close 22 ₂ . During this period, the braking oil pressure for the rear wheels does not increase. At this time, valves 23 ₁ , 23 ₂
Since the seating pressure on the opening edges of the communication holes 22 ₁ and 22 ₂ is determined by the set load of the closing springs 25 ₁ and 25 ₂ , an excessive increase in the seating pressure can be prevented by setting the set load appropriately. Hold down, valve 23 ₁ ,
23 ₂ , etc. can be extended.

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, effective braking can be performed without causing skidding in each wheel.

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', Bf, and Br of the system 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 processing accuracy, these can be integrated.

As described above, according to the present invention, a common housing is interposed in the middle of the first and second flow paths, and a pair of left and right pressure receiving pistons are slidably connected to the cylinder holes in the housing, and the inner parts of these pressure receiving pistons are A first channel is provided at the end side and communicates separately with the upstream side of the first and second flow paths.
and a second input hydraulic chamber, and first and second output hydraulic chambers are respectively formed on the outer end side and communicated separately with the downstream of both flow paths, and the pressure receiving pressure of each output hydraulic chamber of each pressure receiving piston is formed. The area is made larger than the pressure receiving area of each input hydraulic chamber side, and each adjacent input and output hydraulic chamber is biased outward by a closing spring to open at the outward sliding limit of each pressure receiving piston. A common first pressure regulating spring is compressed between both the pressure receiving pistons, communicating through a valve that closes when the valve is slid inward;
A valve moving piston having both ends facing the first and second input hydraulic pressure chambers is slid into the small cylinder holes of both pressure receiving pistons, and a pair of opposing shoulders is formed in the center of the valve moving piston. A pair of washers are provided in contact with each shoulder and the inner end of each of the pressure receiving pistons adjacent thereto in a separable manner, and a common second pressure regulating spring, which is weaker than the first pressure regulating spring, is compressed between the two washers. the valve moving piston and the valve are interconnected with a predetermined play in the axial direction, and the valve moving piston moves from a neutral position in response to a pressure difference between the first and second input hydraulic chambers. When the vehicle moves a predetermined distance or more, the valve on the opposite side to the direction of travel is opened, so normally efficient braking can be achieved, and if one of the braking hydraulic circuits breaks down, The other system acts as a bypass, braking the rear wheels with the same force as the front wheels, making up for the lack of braking power in the rear wheels.

Furthermore, since the second pressure regulating spring that biases the valve moving piston to the neutral position and the closing spring that biases the valve outward are each independently provided, a set load is applied to each spring according to its function. By providing this pressure, the valve moving piston can be reliably held in the neutral position during normal times, and the seating pressure of the valve can be made appropriate to extend its service life.

Furthermore, one common first pressure regulating spring is sufficient for a pair of pressure receiving pistons, and one common second pressure regulating spring is sufficient for a pair of washers, which can contribute to simplifying the structure. .

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a braking device for a vehicle, and FIG. 2 is a longitudinal sectional plan view of essential parts showing an embodiment of the device of the present invention. Br, Br′...Rear wheel brake, C...Brake hydraulic control device, M...Master cylinder, _L1 , _L2 ...First and second flow passages, ₃₁ , ₃₂ ...Housing, ₇₁ ，
7 ₂ ... Cylinder hole, 9 ₁ , 9 ₂ ... Pressure receiving piston,
10 ₁ , 10 ₂ ... small cylinder hole, 11 ₁ , 11 ₂ ...
... Valve moving piston, 16 ₁ , 16 ₂ ... Washer,
18 ₁ , 18 ₂ ...first and second input hydraulic chambers, 19
₁ , 19 ₂ ...first and second output hydraulic chambers, 22 ₁ ,
22 ₂ ... Communication hole, 23 ₁ , 23 ₂ ... Valve, 2
5 ₁ , 25 ₂ ... closing spring, 26 ₁ , 26 ₂ ... connector.

Claims (1)

[Claims] 1 The output hydraulic pressure of the master cylinder M is passed through the first and second flow paths L ₁ and L ₂ to the left and right rear wheel brakes.
In a vehicle braking system in which hydraulic pressure is supplied separately to the hydraulic operating parts of Br and Br', common housings 3 ₁ and 3 ₂ are interposed between the first and second flow paths L ₁ and L ₂ . , the cylinder hole 7 in the housing 3 ₁ , 3 ₂
A pair of left and right pressure receiving pistons 9 ₁ , _{9 2 are} slid together on the inner ends of these pressure receiving pistons 9 _{1 ,} 9 ₂ .
First and second input hydraulic chambers 18 ₁ and 18 ₂ that communicate separately upstream of the first and second flow paths L ₁ and L ₂ ,
Further, on the outer end side, first and second output hydraulic chambers 19 ₁ , 1 respectively communicate with the downstream of the flow paths L ₁ , L ₂ .
9 ₂ respectively, and each pressure receiving piston 9 ₁ , 9 ₂
The pressure receiving area of each output hydraulic chamber 19 ₁ , 19 ₂ is made larger than the pressure receiving area of each input hydraulic chamber 18 ₁ , 18 ₂ , and a closing spring 25 ₁ , communicating via valves 23 1 and 23 ₂ which are urged outward by the pressure receiving pistons 9 ₁ and 9 ₂ and open at the limit of outward sliding of the pressure receiving pistons 9 ₁ and 9 ₂ and closed when they slide inward; A common first pressure regulating spring 12 is compressed between both the pressure receiving pistons 9 ₁ and 9 ₂ , and valve moving pistons 11 ₁ and ₁₁ have both ends facing the first and second input hydraulic chambers 18 ₁ and 18 2 . ₂ into the small cylinder holes 10 ₁ , 10 ₂ of the pressure receiving pistons 9 ₁ , 9 ₂ , and a pair of shoulders 13 ₁ , 13 ₂ facing each other at the center of the valve moving pistons 11 ₁ , 11 ₂ . A pair of washers 16 1 and 16 2 are provided on each shoulder portion 13 ₁ and 13 ₂ and the inner end portion of each of the pressure receiving pistons 9 ₁ and 9 ₂ adjacent to the shoulder portions 13 ₁ and 13 ₂ so as to be able to separate from each other. A common second pressure regulating spring 17 weaker than the first pressure regulating spring ₁₂ is compressed between the valve moving pistons 11 _{1 ,} 11 ₂ and the valve 2 .
3 ₁ and 23 ₂ are connected to each other with a predetermined play in the axial direction, and the valve moving pistons 11 ₁ and 11 ₂ respond to the pressure difference between the first and second input hydraulic chambers 18 ₁ and 18 ₂ . Accordingly, when the valve 23 1 moves from the neutral position by a predetermined distance or more, the valve 23 ₁ on the opposite side to the moving direction
23 ₂ is characterized by opening the valve.
Brake hydraulic control device in vehicle braking system.