JPH0215419B2 - - 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, which has a brake hydraulic circuit configured into two independent systems, and in particular, a brake hydraulic pressure control device for separately supplying the output hydraulic pressure of a master cylinder to the hydraulic operating parts of a pair of left and right rear wheel brakes. A common housing is interposed between the first and second flow paths, a pair of left and right pressure receiving pistons are slid into cylinder holes in this housing, and the first and second First and second input hydraulic chambers are formed on the upstream side of the flow path and communicate with each other separately, and first and second output hydraulic chambers are formed on the outer end side of the flow path that communicate with each other on the downstream side of the flow path, respectively. The pressure receiving area on each output hydraulic chamber side of the pressure receiving piston is made larger than the pressure receiving area on each input hydraulic chamber side, and the pressure receiving area is biased outwardly by a coil spring between each adjacent input and output hydraulic chambers. A common pressure regulating spring is compressed between both the pressure receiving pistons, communicating through a valve that opens at the limit of outward sliding of the piston and closes when sliding inward, and controls the first and second input hydraulic pressures. A valve moving piston with both ends facing the chamber is slid into a small cylinder hole of the pressure receiving piston, and the valve moving piston and the valve are interconnected with a predetermined free play gap in the axial direction, so that both input hydraulic pressures are This invention relates to a device in which when a large pressure difference occurs between chambers, a valve moving piston moves to a low pressure side together with a pressure receiving piston on a high pressure side to open a valve on a high pressure side. According to such a brake hydraulic control 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, and the rear wheel load is reduced due to the front tilt of the vehicle body. Even if the hydraulic pressure decreases, efficient braking can be obtained, and if one system of the brake hydraulic circuit fails, a bypass function is activated and the rear wheels can be strongly braked together with the front wheels by the other system.

By the way, in conventional brake hydraulic control devices of this kind, in order to connect the valve and the valve moving piston with each other with a certain free movement gap, for example, the method disclosed in Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 53-86976, a connecting shaft having a stopper flange at the tip is provided protruding from the valve, a connecting hole into which the stopper flange slides is provided in the valve moving piston, and the stopper flange is provided in the valve moving piston. Resiliently locking opposing clips on the inner circumferential wall of the connecting hole with a certain free space between them on the back surface of the flange;
A coil spring is installed between this clip and the valve.

However, in the connection structure of the valve and the valve moving piston as described above, if the stopper flange repeatedly contacts the clip and a load is repeatedly applied to the clip, there is a risk that the clip will separate from the connecting hole of the valve moving piston. Its reliability cannot be said to be sufficient.

The present invention has been made in view of the above circumstances, and has a simple structure, easy assembly, and a highly reliable connection structure for a valve and a valve moving piston, and provides a brake hydraulic control system for a braking device for a vehicle. The purpose is to provide equipment.

To achieve this objective, the present invention provides a connecting shaft with a stopper flange at the tip at the outer end of the valve displacement piston, and a connecting shaft disposed at the inner end of the valve that moves on the connecting shaft and has a stopper flange at the tip. Connecting cylinders each having an end wall that can come into contact with the back surface of the flange are provided protrudingly, the floating gap is provided between the stopper flange and the end wall, and the peripheral wall and end wall of the connecting cylinder are A large notch and a small notch are respectively provided through which the stopper flange and the connecting shaft can pass, and the coil spring compressed between the valve and the valve moving piston is fitted onto the outer periphery of the connecting cylinder to form at least the small notch. The opening is closed.

An embodiment of the present invention will be described below with reference to the drawings.

First, Fig. 1 shows the hydraulic circuit of an automobile's braking system. Two sets of hydraulic actuators are installed in the front and rear wheel brakes Bf, Br' and Bf', Br, which are located diagonally to each other and form a set. mutually independent first and second flow paths L ₁ and L ₂ extending from the output side of the formula master cylinder M;
are connected separately, and these first and second flow paths L ₁ ,
A common brake hydraulic control device V is provided on the way _L2 reaches the rear wheel brakes Br, Br'. This brake hydraulic control braking V automatically reduces each rear wheel brake hydraulic pressure at a fixed ratio to the front wheel brake hydraulic pressure of the same system during heavy braking, and reduces the rear wheel load by tilting the vehicle forward. is also for efficient braking,
Next, the specific configuration will be explained with reference to FIG.

The double master cylinder M is configured in a tandem type, and when the brake pedal 1 is actuated, a pair of front and rear pistons 2 ₁ and 2 ₂ in the cylinder are moved to the first and second positions, respectively.
Pressure oil can be supplied from the second output ports 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 V.

The brake hydraulic control device V is configured laterally 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 sliding together. A common strong pressure regulating spring 12 is compressed between both pressure receiving pistons 9 ₁ and 9 ₂ , and both valve moving pistons 11 ₁ and 11 ₂
In between, shoulder portions 13 ₁ of each piston 11 ₁ , 11 ₂ ,
_{A relatively weak one _ _ _ _ _} A positioning spring 17 is provided.

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 to each other so that they are always in operation.

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 penetrates. Each valve 23 ₁ , 23 ₂
Coil springs 25 ₁ , 25 ₂ are compressed between the valve moving pistons 11 ₁ , 11 ₂ , respectively, to urge them away from each other, and normally the valve opening rods of the valves 23 ₁ , 23 ₂ 24 ₁ , 24 ₂ come into contact with the end walls of the cylinder holes 7 ₁ , 7 ₂ to hold the valves 23 ₁ , 23 ₂ in the open position at the outward sliding limit of each pressure receiving piston 9 ₁ , 9 ₂ . It's getting old. The pressure receiving pistons 9 ₁ and 9 ₂ move inward and open the small cylinder hole 1.
When the end walls of 0 ₁ and 10 ₂ come into contact with the valves 23 ₁ and 23 ₂ , the communication holes 22 ₁ and 22 ₂ are closed.

Each opposing valve 23 ₁ , 23 ₂ and the valve moving piston 11 ₁ , 11 ₂ are connected by a connecting device C ₁ , C _{2 ,} respectively. Since the coupling devices C ₁ and C ₂ are constructed symmetrically, only the left-hand one C ₁ will be explained in detail with reference to FIGS. 3-5.

The valve moving piston 11 ₁ is integrally formed with a connecting shaft 31 extending from its outer end toward the valve 23 ₁ , and this connecting shaft 31 is provided with a stopper flange 32 at its tip. On the other hand, the valve 23 ₁ has
A connecting cylinder 33 extending from the inner end toward the valve moving piston 11 ₁ is integrally formed. This connecting cylinder 33 is integrally molded with the valve 23 ₁ from synthetic resin, and has an end wall 33 a at its tip that can slide on the connecting shaft 31 and come into contact with the back surface of the stopper flange 32 . The end wall 33a and the stopper flange 32 normally face each other with a predetermined free movement gap _l2 .

The peripheral wall and end wall 33a of the connecting cylinder 33 are provided with a large notch 34 and a small notch 35 through which the stopper flange 32 and the connecting shaft 31 can pass, respectively. Therefore, during assembly, the stopper flange 32
If the connecting shaft 31 is inserted into the large and small notches 34 and 35 from the side of the connecting cylinder 33, the stopper flange 3
2 can be easily stored in the connecting tube 33.

In addition, the valve moving piston 11 ₁ and the connecting cylinder 3
Annular step portions 36 and 37 are formed at opposite ends of the coil spring 25 1 , respectively, and both ends of the coil spring 25 ₁ are fitted into these step portions 36 and 37 to be attached. Thus, the coil spring 25 ₁ has at least the small notch 35
The opening of the connecting shaft 31 is closed to prevent the connecting shaft 31 from coming off the small notch 35.

The floating gap l ₂ is larger than the distance l ₁ that the pressure receiving pistons 9 ₁ and 9 ₂ move from the open position to the closed position of the valves 23 ₁ and 23 ₂ , and this distance l ₁ and the small cylinder hole 10 ₁ , 10 ₂ with washers 16 ₁ , 16 ₂
is set smaller than the sum of the distance _l3 that can be traveled.

A small hole 28 communicating with the outside is provided at the joint between the housings 3 ₁ and 3 ₂ , and a one-way seal member 29 is provided inside this joint to prevent dust from entering from the outside. ing. This one-way seal member 29 allows hydraulic oil, etc. to leak from the inside to the outside, and the pressure receiving piston 9 ₁ ,
Seal member 3 between 9 ₂ and cylinder holes 7 ₁ and 7 ₂
0 ₁ , 30 ₂ , etc. are worn and damaged, and the hydraulic oil leaks into the large diameter holes 8 ₁ , 30 2 , etc.
8 ₂ , the hydraulic oil is allowed to flow out through the one-way seal member 29 and the small hole 28, and the failure can be detected as an abnormal drop in the oil level in the reservoir of the master cylinder M.

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 set loads 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 ,
19 ₁ and 18 ₂ and 19 ₂ are in communication. Therefore, if the brake pedal 1 is operated here, the output hydraulic pressure of the master cylinder M becomes the first
and is transmitted to each downstream of the second flow path L ₁ , L ₂ , and the front,
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 spring 9 ₂ becomes larger than the set loads of the pressure regulating spring 12 and the positioning spring 17, and the pressure receiving pistons 9 ₁ and 9 ₂ slide inward while compressing the springs 12 and 17, respectively. On the other hand, at this time, approximately the same hydraulic pressure is applied to the outer ends of each valve moving piston 11 ₁ , 11 ₂ , so these pistons 11
₁ , 11 ₂ do not move, and each valve 23 ₁ ,
23 ₂ is pressed outward by springs 25 ₁ and 25 ₂ ,
The valve opening rods 24 ₁ , 24 ₂ are kept 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 , 23 ₂ close the communicating holes 22 ₁ , 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.

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 flange 32 at the outer end is the valve 23 ₁
It comes into contact with the end wall 33a of the connecting cylinder 33 at the inner end, and moves the valve 23 ₁ inward. 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 1
1 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 pressure receiving piston 9 ₂ which is an external force.

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 flange 32 of the valve moving piston ₁₁₁ is held in contact with the connecting cylinder 3.
3 remains in contact with the end wall 33a of No. 3. Therefore, at this time, the valve 23 ₁ opens the communication hole 22 ₁ . As a result, the output oil pressure of the master cylinder M remains unchanged in the first output oil pressure chamber 19 ₁
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 V is provided with a bypass function.

As described above, according to the present invention, a connecting shaft with a stopper flange at the tip is attached to the outer end of the valve moving piston, and a connecting shaft that moves on the connecting shaft and has a stopper flange attached to the inner end of the valve. Connecting cylinders each having an end wall that can come into contact with the back surface are provided protrudingly, the floating gap is provided between the stopper flange and the end wall, and the stopper is provided on the peripheral wall and end wall of the connecting cylinder. A large notch and a small notch are respectively provided through which the puff flange and the connecting shaft can pass, and the coil spring compressed between the valve and the valve moving piston is fitted onto the outer periphery of the connecting cylinder, and at least the small notch is opened. Since the portions are closed, the valve and the valve moving piston can be easily connected by simply pushing the stopper flange and the connecting shaft from the side of the connecting cylinder into the large notch and the small notch, respectively. Furthermore, the opening of the small notch can be closed by the coil spring that biases the valve in the closing direction, and the connecting shaft can be reliably prevented from coming off the small notch, thus closing the opening of the small notch. No special parts are required, the structure is simple and highly reliable,
It is possible to obtain a connecting structure for the valve and the valve moving piston, which in turn can contribute to improving the reliability of the brake hydraulic control device.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a hydraulic circuit diagram of an automobile braking system, Fig. 2 is a longitudinal cross-sectional plan view of a brake hydraulic control device used in the braking system, and Fig. 3 is a hydraulic circuit diagram of an automobile braking system. Enlarged view showing the connection structure of the valve and valve moving piston of the above device, 4th and 5th
The figure is a cross-sectional view taken along the line 3 and 3. M... Master cylinder, L ₁ , L ₂ ... First and second flow paths, l ₂ ... Idle gap, 3 ₁ , 3 ₂ ... Housing, 7 ₁ , 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, 12 ... Pressure regulating spring, 18 ₁ , 18 ₂ ... First and second input hydraulic chambers,
19 ₁ , 19 ₂ ...first and second output hydraulic chambers, 23 ₁ ,
23 ₂ ... valve, 25 ₁ , 25 ₂ ... coil spring,
31... Connection shaft, 32... Stopper flange, 3
3... Connecting tube, 34... Large notch, 35... Small notch.

Claims (1)

[Scope of Claims] 1. In the middle of the first and second flow paths L ₁ and L _{2 for separately supplying the output hydraulic pressure of the master cylinder M to the hydraulic operating parts of the pair of left and right rear wheel brakes Br and Br'} . A common housing 3 ₁ , 3 ₂ is installed, and a pair of left and right pressure receiving pistons 9 ₁ , 9 ₂ are slid into cylinder holes 7 ₁ , 7 ₂ in the housings 3 ₁ , 3 _{2 .} , 9 ₂ , the first and second channels
The first and _second input hydraulic chambers 18 1 and 18 ₂ are connected to the upstream side of L 1 and L 2 separately, and the first and second input hydraulic chambers 18 ₁ and 18 ₂ are connected separately to the downstream side of both flow paths L ₁ and L ₂ on the outer end side. 1 and 2 output hydraulic chambers 19 ₁ and 19 ₂ are respectively formed, and each output hydraulic chamber 19 ₁ and 1 of each pressure receiving piston 9 1 and _{9 2} is formed.
The pressure receiving area on the 9 ₂ side is made larger than the pressure receiving area on the input hydraulic chambers 18 ₁ and 18 ₂ side, and each adjacent input,
The pressure receiving pistons 9 1 , ₉ are biased outwardly between the output hydraulic chambers by the coil springs 25 ₁ , 25 ₂ , respectively.
A common pressure regulating spring ₁₂ is connected between the pressure receiving pistons 9 ₁ and 9 2 , which communicate through valves 23 ₁ and 23 ₂ that open at the outward sliding limit of 9 ₂ and close when they slide inward. Valve moving pistons 11 ₁ , 11 ₂ are contracted and have both ends facing the first and second input hydraulic chambers 18 ₁ , 18 _{2 .}
The small cylinder holes 10 of the pressure receiving pistons 9 ₁ and 9 _2
1 and 10 ₂ , and this valve moving piston 11
₁ , 11 ₂ and the valves 23 ₁ , 23 ₂ are interconnected with a predetermined floating gap l ₂ in the axial direction, and a large pressure difference is generated between the input hydraulic chambers 18 ₁ and 18 ₂ . In a braking hydraulic control device for a vehicle braking system, in which the valve moving piston moves to the low pressure side together with the high pressure side pressure receiving piston to open the high pressure side valve when the valve moving piston ₁₁ A connecting shaft 31 with a stopper flange 32 at the tip is attached to the end, and an end wall movable on the connecting shaft ₃₁ and capable of coming into contact with the back surface of the stopper flange 32 is attached to the inner end of the valve 231. The connecting cylinders 33 provided with the connecting cylinders 33 are respectively protrudingly provided, the floating gap _l2 is provided between the stopper flange 32 and the end wall, and the peripheral wall and the end wall of the connecting cylinder 33 are provided with the connecting cylinders 33 and the connecting cylinders 33 protruding from each other. A large notch 34 and a small notch 35 are respectively provided through which the shaft 31 can pass, and the coil spring 25 ₁ compressed between the valve 23 ₁ and the valve moving piston 11 ₁ is fitted onto the outer periphery of the connecting cylinder 33. A brake hydraulic control device for a vehicle brake system, characterized in that at least an opening of the small notch 35 is closed.