JPH0215417B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to a two-system control hydraulic pressure control valve for a vehicle;
In particular, it relates to a hydraulic control valve having a pair of pressure reducing valves arranged in series.

(b) Prior art In order to maintain appropriate braking force on the front and rear wheels of vehicles, especially automobiles, after the input hydraulic pressure from the master cylinder exceeds a certain value (node point hydraulic pressure), the rear wheels are It has become common to install a hydraulic pressure control valve that proportionally reduces the hydraulic pressure supplied to the brakes. Among them, diagonal split brake systems,
In other words, the hydraulic pressure control valve used in a brake system that divides the piping from the master cylinder to the brake into two systems, and connects the right front wheel and left rear wheel to one of them, and the left front wheel and right rear wheel to the other, is 1. When the system fails,
In order to exert sufficient braking force, it is desirable to have a "failure compensation function" that stops the depressurizing action of the survival system and supplies higher hydraulic pressure than normal to the rear wheel brakes.

Several such hydraulic pressure control valves are already known, but none of the conventional ones have poor performance or performance.
There are difficulties in processability and economy. For example, JP-A-56
Publication No. 60759 discloses that a fail-safe piston is provided between a pair of pressure reducing valves arranged in series in opposite directions, and when one system fails, the piston moves the valve body or valve seat of the pressure reducing valve between the two. A technique for moving the passage to a position where it cannot be closed is shown, but the one in Figure 1 of the same publication requires two corner hydraulic pressure setting springs, and these springs set the hydraulic pressure in two systems during normal operation. I can't even hope for a balance function. Also,
The one in Figure 2 has a larger diameter hydraulic piston, which may slow its movement and reduce responsiveness, while the one in Figure 3 requires two sleeves to transmit the moving force of the piston. shall be.

Furthermore, Japanese Utility Model Publication No. 52-12062 discloses a technique in which when one system fails, the second piston pushes the valve seat into the large diameter part of the cylinder hole, allowing the outer periphery of the valve seat to communicate directly with the input and output hydraulic chambers. However, special ingenuity is required to arrange this as a two-system control valve.

That is, if we now temporarily set up a pair of pressure reducing valves as
Arrange it as shown in Figure 1 of No. 60759.
If the valve seat on the surviving side is pushed out to the large diameter part of the cylinder hole by the second piston in the event of system failure, the setting spring at the break point, the second piston,
The problem is that two hydraulic pressure chambers are required to apply hydraulic pressure from other systems to the second piston. Furthermore, in the case where the surviving valve seat is moved by the second piston in the pressure reducing valve arrangement as shown in FIG. Two hydraulic chambers are required for applying hydraulic pressure, and in any case, the structure becomes extremely complicated, which is disadvantageous in terms of economy and workability. For this reason, the present applicant has previously proposed several series-type hydraulic control valves that eliminate these drawbacks.

This valve has a pressure reducing valve consisting of a pair of lip seals and a plunger arranged symmetrically at both ends of one corner hydraulic pressure setting spring, and is also slidable in the axial direction and has two systems of hydraulic pressure at both ends. Each of the pair of plungers is fluid-tightly fitted into a piston that is equally received, and in the event of a failure in one system, this piston will hold the surviving plunger until its valve head either fits into the lip seal or completely passes through and is placed on the inner diameter side of the lip seal. The fluid is moved to the failed side until a bypass path connecting the input and output hydraulic pressure chambers appears, thereby stopping the decompression effect on the surviving side and maintaining the relationship of input hydraulic pressure = output hydraulic pressure. This is what I did.

(C) Problems to be Solved by the Invention However, in the above-mentioned valve, since the spring force of the single corner hydraulic pressure setting spring is equally transmitted to the two systems of plungers, the output hydraulic pressure difference between the two systems is Although it has the characteristics of being very small, and improving the processability of the valve body, the economic effect is also increased.
When one system fails, the valve head of the plunger gets stuck in the lip seal, so there are concerns about the durability of the lip seal. In addition, after repairing a failure, the plunger valve head needs to escape from the lip seal and return to the non-operating position, but if the load on the corner hydraulic pressure setting spring is small (in the case of low corner hydraulic pressure), the lip seal will close. There is also the problem that it is difficult to restore due to the tightening resistance.

(d) Means for Solving Problems The purpose of the present invention is to take advantage of the features of the control valve described above, eliminate concerns about the durability of the seal valve, and facilitate the return of the plunger after repairing a failure. Our objective is to provide a series hydraulic pressure control valve for two-system controlled operation.
This objective will be achieved by the following means:

That is, the hydraulic pressure control valve of the present invention replaces the lip-seal type pressure reducing valve with a sealing means that passes through the large-diameter portion that partitions the input hydraulic pressure chamber and the output hydraulic pressure chamber, and the input hydraulic pressure chamber to make it liquid-tight. A hydraulic pressure-responsive plunger having a small diameter portion that projects to the atmosphere, and a valve mechanism that is provided separately from the sealing means and opens and closes a communication path between the input hydraulic pressure and the output hydraulic pressure chamber as the plunger moves. A pressure reducing valve is configured, and when one system fails, a piston provided between both pressure reducing valves moves the surviving plunger to the failed side, and an input hydraulic pressure chamber and an output hydraulic chamber are formed on the outer periphery of the large diameter part of this plunger. The configuration is such that a bypass path that communicates with the pressure chambers appears, and the intended purpose is achieved based on this point.

(E) Embodiments Examples of the present invention will be described below with reference to the attached drawings.

The hydraulic pressure control valve shown in Fig. 1 has two input ports 2 and 2' connected to a tandem master cylinder A in a valve body 1, and the hydraulic pressure introduced from these ports is directly supplied to the front wheel brake FB. a first output port 3, 3' to supply the rear wheel brake RB with proportionally reduced hydraulic pressure after the input hydraulic pressure exceeds the turning point hydraulic pressure, and a second output port 4, 4' with a small diameter. A stepped cylinder 5 is provided in which guide holes 5a, 5a' and stoppers 5b, 5b' are formed coaxially and symmetrically.
In addition, pressure reducing valves consisting of a pair of plungers 6, 6' and poppet valves 7, 7' are installed symmetrically in the cylinder 5, and are fixed to the rear ends of both plungers 6, 6'. A single hydraulic pressure setting spring 9 is compressed between the spring retainers 8 and 8', and biases the left and right plungers in the valve opening direction. Further, the rear end portions of each plunger 6, 6' protrude liquid-tightly and slidably into the atmospheric chamber 11 via cup seals 10, 10'. Further, in the middle part of the cylinder 5, the inner diameter side of one end is a cup seal, and the outer diameter side is O-rings 13, 13'.
A piston 14 is slidably inserted therein, the pistons 14 being integral with each other and having their other ends press-fitted into each other.

Also, each plunger 6, 6' has an O-ring 1.
Input hydraulic chamber 16,1 at the outer periphery via 5,15'
6' and output hydraulic pressure chambers 17, 17', and liquid passages 6b, 6'b whose one end opens to the input hydraulic pressure chamber and the other end opens to the output hydraulic pressure chamber. is formed, and inside this passage, springs 18, 18'
The poppet valves 7, 7' are pressed by the valve receivers 19, 19' at the tips of the guide holes, and the valve seats 20, 20' repeatedly separate from and separate from the valve parts 7a, 7'a of the poppet valves during braking. It is press-fitted.

As shown in FIG. 4, the hydraulic pressure control valve of the present invention has an input hydraulic pressure chamber including a chamber 16A that applies hydraulic pressure to the piston 14 and one surface of the plunger, and a chamber 16A located in front of the plunger, and a valve body 1. Liquid passage 21 provided in
Furthermore, the pressure reducing valve is housed in the valve seat 21 formed in the main body 1 and in the input port 16B, and as the plunger moves, it is inserted into the valve seat 20A. The same effect can be obtained even when the valve body 22 is configured to repeatedly separate and separate, and the spring 23 biases the valve body in the valve closing direction, and the valve body is arranged symmetrically in the left and right directions.

In addition, as shown in FIG. 5, the large diameter portion 6a of the plunger 6 is extended to the tip of the plunger, and furthermore, the large diameter portion of the plunger is extended to the output hydraulic pressure chamber 17 side with the seal 24 attached to the valve body 1 as a boundary. The same effect can be obtained by providing grooves 25 on the outer periphery and arranging them symmetrically in the left and right directions.

However, in the control valves shown in FIG. 1 and FIG.
a, 5'a, and in the control valve shown in FIG. 5, the distance l ₁ from one end of the groove 25 to the tip of the cup seal ₂₄ and the amount of movement of the piston 14 l ₂ (see FIG. 1). ) are all set to the relationship l ₁ < l ₂ .

(F) Operation The operation of the control valve shown in FIG. 1 will be explained below, taking the hydraulic system on the right as an example.

First, under normal conditions, the output fluid pressure
Since P _M = P _M ', the piston 14 is stopped at the center of the cylinder, and the working fluid from the master cylinder is introduced from the input port 2 into the input hydraulic pressure chamber 16, from which it directly flows out to the output port 3. However, the liquid flows out to the output port 4 through the liquid passage 6b and further through the gap between the poppet valve 7 and the valve seat 20. At this time, if the turning point hydraulic pressure set by the spring 9 is P _s , then P _M < P _s at the beginning of braking, so the force P _M ·A that pushes the plunger 6 to the left is
This is smaller than the set load F of the spring 9 opposing this, so the plunger 6 is stationary and the input hydraulic pressure is directly output as the output valve pressure _PR .

After that, the input hydraulic pressure gradually increases and P _M・A=F
Then, the plunger 6 moves to the left and the valve seat 20
comes into contact with the valve portion 7a of the poppet valve, and the passage between the input and output hydraulic pressure chambers is blocked. Incidentally, the balance equation of the force acting on the plunger 6 is P _R (B-C) = P _M (B-C-A) + F, ignoring the pressing force of the spring 18 and the load increase due to the slight compression of the spring 9. From the above equation and P _s = P _M = P _R , the corner liquid pressure P _s
=F/A is derived.

After this, when the input hydraulic pressure further increases △P _M , P _R (B-C) < (P _M + △P _M ) (B-C-A) + F, and the plunger 6 is slightly displaced to the right. , the hydraulic fluid flows into the output hydraulic pressure chamber from a space apart from the valve seat 20. Also, when the output hydraulic pressure increases △P _R , (P _R +△P _R ) (B-C) = (P _M +△P _M ) (B-C-A) + F, and the valve seat 20 comes into contact with the poppet valve 7 again to block the passage, and as a result of this repetition, in the range of P _M > P _s , the pressure reduction ratio tanθ=B-C-A/B-C= in FIG.
The depressurizing effect is performed even at a value of 1-A/B-C<1.

Next, a case will be described in which one of the two hydraulic circuits fails. Now, if the pressure increasing function of the left hydraulic system is lost, P _M '=0, and the only force pushing the plunger 6 and piston 14 to the right is the load F of the spring 9. Therefore, when P _M D>F (in this case P _M <P _s ) on the surviving side,
The piston 14 starts moving to the left, but the force relationship between the piston and the spring 9 is predetermined as P _M (D-
B)>F+K・l ₂ (where K is the spring constant of the spring 9), therefore, the piston 14 moves while compressing the spring 9 until it comes into contact with the stopper 5b', and moves through the retainer 8. The plunger 6 is moved along with the poppet valve 7 by _l2 in the valve closing direction. At this time, since l ₂ > l ₁ , the large diameter portion 6a of the plunger 6 escapes from the guide hole 5a as shown in FIG. 2 during the movement process, and therefore enters the outer periphery of the plunger large diameter portion 6a.・Output hydraulic chamber 16,
17 direct bypass paths are formed, P _M > P _s
Even so, the relationship P _M = P _R is maintained. Note that when the right hydraulic system fails, P _M =0, so P _M ′=
becomes P _R ′.

Similarly to the control valve shown in FIG. 4, the large diameter portion 6a of the plunger escapes from the guide hole 5a to form a bypass path between the input and output hydraulic pressure chambers 16A and 17, but the control valve shown in FIG. Even if the large diameter portion 6a does not completely escape from the guide hole, a bypass path is formed when one end of the groove 25 on the outer periphery of the plunger enters the input hydraulic pressure chamber 16.

(G) Effect As explained above, this invention allows the input and output hydraulic pressure chambers to be fluid-tightly partitioned during normal operation by moving the surviving plunger to the failed side using a piston when one system fails. The large diameter part of the plunger
Either escape through the guide hole of the valve body, or expose one end of the groove provided on the outer periphery of the large diameter part to the input hydraulic pressure chamber, and expose a bypass path that directly connects to the outer periphery of the large diameter part and the output hydraulic pressure chamber. As a result, the poppet valve or the valve body only comes into contact with the valve seat, and therefore, the durability of the control valve is improved compared to the example of the prior application.

In addition, the plunger that moves along with the piston due to the braking operation when one system fails does not have the resistance of the lip seal as seen in the prior application, so even if the load on the corner hydraulic pressure setting spring is relatively small, After repairing the defect, it can smoothly return to the non-operating position.

Furthermore, by applying equal force to the two plungers using a common spring, the difference in hydraulic pressure between the two systems during normal operation is minute, and almost equal braking force is applied to both the front and left wheels. Since the internal parts are arranged in series, the main body is easy to work with, and it is easy to integrate the valve into the master cylinder, etc., which are the advantages of the previous application, and the advantages of the previous application can be maintained. Compared to the control valve shown in FIG.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of the hydraulic pressure control valve of the present invention, Fig. 2 is a partial sectional view showing the operating state when one system fails, and Fig. 3 is a characteristic curve of rear wheel braking hydraulic pressure. 4 and 5 are partial sectional views showing other embodiments. 1... Valve body, 2, 2'... Input port, 3,
3', 4, 4'...Output port, 5...Cylinder,
5a, 5a'... Guide hole, 5b, 5b'... Stopper, 6, 6'... Plunger, 6a, 6'a... Large diameter section, 7, 7'... Poppet valve, 9... Break point Hydraulic pressure set spring, 11... Atmospheric chamber, 14... Piston, 16, 16', 16A, 16B... Input hydraulic pressure chamber, 17, 17'... Output hydraulic pressure chamber, 18, 1
8'... Spring, 20, 20', 20A... Valve seat, 22... Valve body, 23... Spring, 25...
...Groove, A...Plunger small diameter section cross-sectional area, B...Plunger large diameter section cross-sectional area, C...Valve seal section cross-sectional area, D...Piston cross-sectional area.

Claims (1)

[Scope of Claims] 1. A large-diameter portion provided with a sealing means on the outer diameter side for fluid-tightly partitioning an input hydraulic pressure chamber and an output hydraulic pressure chamber between the cylinder hole provided in the valve body and the input hydraulic pressure chamber. A hydraulic response plunger is provided separately from the seal means and has a small diameter portion that passes through the hydraulic pressure chamber and projects into the atmospheric chamber inside the piston described later, and is configured to move between the input hydraulic pressure chamber and the output hydraulic pressure as the plunger moves. a pair of pressure reducing valves comprising a valve mechanism that opens and closes a communication path between the atmospheric chamber; and a corner hydraulic pressure valve that engages each plunger of the pair of pressure reducing valves in opposite directions at both ends within the atmospheric chamber. A set spring, and small diameter portions of the pair of plungers that are slidable in the axial direction are fitted in a liquid-tight and slidable manner from both ends toward the atmospheric chamber, and both ends face the input hydraulic pressure chamber of each system. The plunger is provided with a piston that receives the hydraulic pressure of two systems equally and remains at a neutral position when the hydraulic pressures of the two systems are equal, and that moves the surviving plunger to the failed side when one of the systems fails, and further, A serial fluid for controlling two systems, wherein the sealing means part is provided with a bypass passage that is opened when the surviving plunger moves beyond its normal stroke to the failed side and communicates the input hydraulic pressure chamber with the output hydraulic pressure chamber. Pressure control valve.