JPH0215420B2 - - 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.

In order to achieve this object, the present invention has a method in which connecting shafts protruding from opposite ends of a valve and a valve moving piston are respectively fitted into both end walls of a hollow cylindrical connector divided approximately along the axis. , a stopper for holding the end wall between the valve and the valve is provided at the tip of the connecting shaft of the valve, and a stopper that faces the end wall with the floating gap provided at the tip of the connecting shaft of the valve moving piston. and fitting the valve side end of the coil spring compressed between the valve and the valve moving piston into the valve side end of the connector, and providing a gap between the other part of the coil spring and the connector. It is characterized by:

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 device 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 in sliding contact with each other. 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 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 ,
Coil springs 25 ₁ and 25 2 are installed between the valves 11 ₂ and 11 ₂ to spring them apart from each other, and normally the valve opening rods 24 ₁ and 24 ₂ of the valves 23 ₁ and 23 ₂ are connected to the cylinders. The valves 23 ₁ , 23 ₂ are held in the open position by contacting the end walls of the holes ₇ 1 , 7 ₂ at the limit of outward sliding of the respective pressure receiving pistons 9 ₁ , 9 ₂ . The pressure receiving pistons 9 ₁ , 9 ₂ move inward and touch the end walls of the small cylinder holes 10 ₁ , 10 ₂ and the valve 2 .
3 ₁ , 23 ₂ contact, the communication holes 22 ₁ , 22 ₂
is occluded.

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 in a symmetrical relationship, only the left-hand one C ₁ will be described. (See Figures 3-5).

At the opposing ends of the valve 23 ₁ and the valve moving piston 11 ₁ , a flange-shaped stopper 31a is provided at the tip.
A short connecting shaft 31 and a long connecting shaft 32, each having a diameter 32a, are integrally protruded, and are fitted into both end walls 26a, 26b of the hollow cylindrical connector 26 of the connecting shafts 31, 32. The outer end wall 26a has a valve ₂₃₁ and a stopper 31a.
The inner end wall 26b is sandwiched therebetween and is substantially fixed on the connecting shaft 31 of the valve 23 ₁ , but the inner end wall 26b is adapted to be able to slide on the connecting shaft 32 of the valve moving piston 11 ₁ . A predetermined free movement gap _l2 is provided between the stopper 32a and the stopper 32a.

As clearly shown in FIG. 4, the hollow cylindrical connector 26 is composed of two half cylinders 33, 33 divided approximately along the axis.
3 and 33 are surrounded by the coil spring 25 ₁ , one end of the coil spring 25 ₁ is fitted into the end of the connector 26 on the valve 23 ₁ side, and the other part is surrounded by the coil spring 25 ₁ and the connector 26. gap g
This configuration is a feature of the present invention. Thus, the original cylindrical shape of the connector 26 is maintained by fitting one end of the coil spring 25 ₁ to the connector 26, and the formation of the gap g allows the coil spring 25 ₁ to expand and contract without being hindered by the connector 26. be able to.

To explain this configuration in detail, in the example shown in FIG. 3, when the coil spring 25 ₁ is molded, the inner diameter of the second and third turn portions 25a at the end on the side of the valve 23 ₁ is slightly smaller than the outer diameter of the connector 26; The inner diameter of connector 2
6, and the outer diameter is set larger than the outer diameter of 2 and 3 above.
The rolled portion 25a is expanded and fitted into the end of the connector 26 on the valve ₂₃₁ side. In addition, in the example shown in FIG. 5, when the connector 26 is molded, the outer diameter of the valve 23 ₁ side end of the connector 26 is 2 and 3 of the coil spring 25 ₁ .
It is slightly larger than the inner diameter of the spring 25 ₁ in the range corresponding to the coil, and the other outer diameter is a coil spring 25 ₁
is set smaller than the inner diameter of the connector 26
The end of the valve 23 ₁ is fitted onto one end of the coil spring 25 ₁ while expanding it.

In order to prevent air bubbles from remaining inside the connector 26, it is effective to make through holes 34, 34 in each half cylinder 33, 33, or to create a gap at the joint of both half cylinders 33, 33. be.

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′. When the brake pedal 1 is operated at this time, the first hydraulic pressure output from the master cylinder M is transmitted only through the first flow path _L1 , and the pressure in the first input hydraulic pressure chamber ₁₈₁ increases, but the second hydraulic pressure increases. The pressure within the input hydraulic chamber ₁₈₂ 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 movement piston 11 ₁ moves a predetermined distance l ₂ , the stopper 32a at its outer end engages the inner end wall 26b of the connector 26, causing the valve 23 ₁ to move 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. Thus, 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 32a of the valve moving piston ₁₁₁ remains engaged with the inner end wall 26b of the connector 26. 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, the connection shafts protruding from the opposing ends of the valve and the valve moving piston are respectively fitted into both end walls of a hollow cylindrical connector divided approximately along the axis, and the valve A stopper for sandwiching the end wall between the valve and the valve is provided at the tip of the connecting shaft of the valve moving piston, and a stopper that faces the end wall with the floating gap provided therein protrudes from the tip of the connecting shaft of the valve moving piston. , the valve side end of the coil spring that is compressed between the valve and the valve moving piston is fitted into the valve side end of the connector, and a gap is provided between the other part of the coil spring and the connector. , the valve and the valve moving piston can be easily connected by simply aligning the divided connectors. In addition, the coil spring that biases the valve in the closing direction can connect the divided connectors and reliably prevent both connecting shafts from coming off from both end walls. It is possible to obtain a connecting structure of a valve and a valve moving piston that is simple in structure and highly reliable, and can contribute to improving the reliability of the brake hydraulic control device.

In particular, since the coil spring has a gap with the connector other than the one end that fits into the connector, the expansion and contraction of the coil spring can be prevented from being hindered by friction of the connector, and as a result, the valve and the valve A moving piston is one that can always approach and move away without causing hysteresis.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is a hydraulic circuit diagram of an automobile brake system, and Figure 2 is a longitudinal cross-sectional plane of a brake hydraulic control device used in the brake system. 3 is an enlarged view showing the connection structure of the valve and valve moving piston of the above device, FIG. 4 is an exploded perspective view of the connector which is the main part, and FIG. 5 is a valve and valve moving piston of another embodiment. FIG. 2 is an enlarged view showing the connection structure of FIG. M... Master cylinder, L ₁ , L ₂ ... First and second flow paths, l ₂ ... Idling 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,
26... Connector, 26a, 26b... End wall, 3
1... Connection shaft, 31a... Stopper, 33... Half cylinder body.

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, 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 ₂₃₁ and the valve moving piston Connecting shafts 31 and 32 protruding from opposite ends of ₁₁ are connected to a hollow cylindrical connector 2 divided approximately along the axis.
The connecting shaft 31 of the valve 23 1 is fitted with the end walls 26 a and 26 b at the tip of the connecting shaft 31 of the valve 23 ₁ .
A stopper 31 that clamps a between the valve ₂₃₁ and the valve 231
a, the floating gap _l2 exists at the tip of the connecting shaft 32 of the valve moving piston ₁₁₁ , and the end wall 26b
A stopper 32a is provided protrudingly facing the valve ₂₃₁ side end of the coil spring ₂₅₁ , which is compressed between the valve ₂₃₁ and the valve moving piston ₁₁₁ , and a valve ₂₃₁ side end of the connector 26. A brake hydraulic control device for a vehicle brake system, characterized in that a gap g is provided between the coil spring 25 ₁ and the connector 26 in other parts.