JPS5963257A - Deceleration sensitive type hydraulic pressure control valve - Google Patents

Abstract

PURPOSE:To enable to correspond sealed-in pressure to vehicle weight at all times without employing orifice or dammy stroke by a structure wherein a differential pressure valve is provided between a hydraulic pressure confining chamber and a deceleration sensitive valve so as to lower the confined pressure by a certain fixed value. CONSTITUTION:The brake pressure of a rear wheel 37 is controlled by a control valve CV, the operating point of which is determined by a control spring 22 and the pressure in the confining chamber 19 to push the control spring 22. The brake pressure of a rear wheel 38 interlocks with that of the rear wheel 37 by means of an interlocking valve JV. The differential pressure valve 27 is provided between the sealed-in chamber 19 and the deceleration sensitive valve GV and serves to lower the confining pressure than the pressure at the inlet 7 by the certain fixed value at all times. Accordingly, the confined pressure rises correspondent to the deceleration of a vehicle and precise hydraulically controlling is resulted. The controlling is more precise than the controlling employing orifice or dammy stroke, however heavy the vehicle weighs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration sensing type hydraulic pressure control valve used in a hydraulic brake system of an automobile or the like.

Hydraulic brakes in automobiles simultaneously brake the front and rear wheels using the mask cylinder hydraulic pressure generated when the brake pedal is depressed, but if the rear wheels lock up before the front wheels, there is a danger that the car will skid. behavior. Therefore, in consideration of the fact that during braking, the vehicle load is biased toward the front and the rear wheels are more likely to lock than the front wheels, the rear wheel brake system controls the hydraulic pressure supplied to the rear wheels while limiting the increase in mask cylinder hydraulic pressure. Insert the valve.

This type of hydraulic pressure control valve responds to the master cylinder hydraulic pressure (artificial hydraulic pressure) against a spring, and when the static pressure exceeds a certain value, it increases the rear wheel brake hydraulic pressure while limiting the increase in static pressure. Control valves such as provocation valves and limiting valves that control (outlet fluid pressure) are known.

However, in both control valves, the constant mask cylinder hydraulic pressure value (critical hydraulic pressure) that starts to limit the increase in rear wheel brake hydraulic pressure remains unchanged, and the front and rear wheel brake force distribution characteristics are constant. However, the ideal 677TK wheel brake force distribution characteristic, in which the 071 rear wheels lock simultaneously, changes so that the rear wheel brake force increases as the vehicle weight increases, and therefore the critical hydraulic pressure increases as the vehicle weight increases. It is necessary to do so.

Therefore, by sealing the mask cylinder IIVEE (which increases as the vehicle weight increases) in a containment chamber when it closes at a vehicle deceleration greater than or equal to the - chamber and generates this constant deceleration, this containment pressure (vehicle weight) can be reduced. Deceleration sensing type hydraulic control in which deceleration sensing pulp is added to the hunt roll valve to compress the spring of the control valve by a corresponding amount and increase the critical hydraulic pressure determined by the spring force of the spring as the weight of the vehicle increases. One valve is in practical use.

This deceleration sensing type hydraulic pressure control valve has a distribution characteristic of front and rear wheel brake force (front and rear wheel brake fluid pressure) as shown by a-b-c (critical hydraulic pressure "81") in Fig. 2 when the vehicle is empty. ,
When the vehicle is loaded, the brake force distribution characteristics between the front and rear wheels approximate the ideal characteristics under any vehicle weight, as shown by a-b'-c' (critical hydraulic pressure P8.) in the figure. The aim is to limit the increase in wheel brake fluid pressure.

However, the occurrence of vehicle deceleration with respect to the increase in mask cylinder hydraulic pressure is shown in FIG. 8 for the case where the mask cylinder hydraulic pressure increases at a rate indicated by α, as indicated by β in the figure.

Therefore, if the deceleration sensing valve supplies the mask cylinder hydraulic pressure as it is to the containment chamber of the control valve, the deceleration sensing valve closes when the vehicle's deceleration pupil reaches the above-mentioned constant value and is contained in the containment chamber. The confinement pressure applied becomes too high and does not correspond to the weight of the vehicle.

Due to this expansion, the vehicle weight becomes particularly noticeable when braking suddenly with a light empty vehicle, as the delay in the onset of vehicle deceleration in response to the increase in mask cylinder hydraulic pressure becomes even greater, and at this time the criticality is reached as shown in Figure 2. The fluid pressure becomes P8□ and a-b-
When the characteristic should be c, the split point increases from b to d, shifting to the characteristic ad.

To prevent this, an orifice is installed in the mask cylinder hydraulic passage to the containment chamber, and a dummy stroke is set on the front side of the loaf of the piston that compresses the spring of the control valve to prevent the supply to the containment chamber. The pressure is increased with a time delay relative to the master cylinder hydraulic pressure α, as shown by γ in FIG. 8, so that the characteristics a-b-c in FIG. 2 can be obtained.

However, when braking with a heavy vehicle loaded, the delay in the onset of vehicle deceleration relative to the rise in master cylinder hydraulic pressure is not as great as when braking with an empty vehicle, even during sudden braking, so the orifice and dummy stroke Unfortunately, the containment pressure became low and could no longer cope with the weight of the vehicle. In this case, as shown in FIG. 2, the critical fluid pressure should be Ps2 and the characteristic should be a-bl-C/, but the split point b' drops to f and a-f-
This leads to the characteristics of g.

In the present invention, a differential pressure valve is inserted into the inlet hydraulic pressure (mask cylinder hydraulic pressure) passage toward the containment chamber to supply the containment chamber with a hydraulic pressure that opens and opens so that it is always lower than the inlet hydraulic pressure by a certain value. If you replace it with Oriais and dummy stroke,
Since the differential pressure valve can direct the hydraulic pressure generated after the inlet hydraulic pressure by a time equivalent to the delay in vehicle deceleration to the containment chamber, the containment pressure can always be made to correspond to the vehicle weight, which solves the above problem. From the viewpoint that it is possible, we hereby propose a deceleration sensing type hydraulic pressure control valve that embodies this idea.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

Fig. 1 shows an embodiment of the deceleration sensing type hydraulic control valve of the present invention, which is designed for two-system piping. Establish II#.

The valve body l is constructed by combining parts 2@, and has a small diameter hole ia, large diameter holes 1b and 10 on the left side, and a large diameter hole 1d on the right side to house the valve inside.
, a hole 1e parallel to these holes, and a hole 1f connected to this hole.
to form. The plunger 8 is slidably fitted into the hole la under the guidance of the retainer 2, and the valve holder 4 is slidably fitted into the hole ld to define chambers 5 and 6. Room 5
A hydraulic inlet boat and a hydraulic outlet boat 8, each opening at .degree. A blind hole 8a opened on the right end surface of the plunger 8 in the figure is communicated with the chamber 5 through a horizontal hole 8b, and a poppet valve body lO is inserted into the blind hole 3a by a spring 1.
1, the valve seat 12 for this poppet valve body is fixedly installed at the open end of the blind hole 3a, and the valve stem of the poppet valve body 10 is biased toward the valve closing direction when the poppet valve body 10 is seated on the valve seat 12. Hole 8
The length should be such that it slightly protrudes from the opening end of a.

A free piston 18 is slidably fitted into the valve holder 4 to define a chamber 14, and the free piston 13 moves the poppet valve body 10 to the open position. Further inside the valve holder 1 are a poppet valve element IO1 spring 11 and a valve seat 12.
A poppet valve body 10', a spring 11', and a valve seat 12', which are exactly the same as those shown in FIG. Pulp holder 4
The small diameter portion at the right end in the figure is slidably inserted into the plug 15 to define a chamber 16, and this chamber 16 is communicated with the chamber 14 at the open position of the poppet valve body 10'. A plug 15 closes the open end of the bore 1d, forming a hydraulic inlet port 16 in the plug that communicates with the chamber 16, and a hydraulic outlet port 17 in the valve body 1 that communicates with the chamber 14.

The piston 18 is slidably fitted into the hole IC to define a containment chamber 19, and the spring 22 is compressed via the spring seat 20.21 between the piston 18 and the plunger 8.
is also elastically supported in the illustrated limit position by another spring 23.

The length of the piston 18 is made equal to the length of the hole IC so that even at the illustrated limit position of the spring seat 20, there is no gap between the spring seat and the piston 18 to provide a dummy stroke.

A ball holder 24 is fitted into the hole 18, and the inside thereof is communicated with the communication boat 9 through an oblique hole B4a. A G ball 25 is housed in the ball holder 24 so as to be movable in the left and right directions in the figure, and the ball valve seat 2 is attached to the G ball.
6 is fixed.

A differential pressure valve 27 to be provided in the present invention is housed in the hole if,
This differential pressure valve includes a valve holder 28 that is slidably fitted into a hole if, and a spring 29 that biases the valve holder n toward the ball holder 24, and is attached to an opening at the left end in the figure of a center hole 28a of the valve holder. A poppet valve body 30, a spring 81 that biases the poppet valve body in the valve closing direction, and a valve seat 32 for the poppet valve body 8o are provided. The valve stem of the poppet valve body 8o has a length such that it slightly protrudes from the corresponding end surface of the pulp holder 28 in the illustrated valve closing position seated on the valve seat 82, and when this end surface collides with the bottom surface of the hole 1f, the poppet valve body 30 shall be in the open position.

A liquid path 83 opens at the bottom of the hole if and reaches the containment chamber 19
is formed in the valve body 1, and a liquid path 24b communicating between the valve holder center hole 28a and the valve hole 28a of the ball valve seat 26 is formed in the ball holder 241.

In the deceleration sensing type hydraulic control valve of the present invention having the above-described structure, the G ball 25 is normally inclined by θ with respect to the horizontal plane H so that the G ball 25 is kept at a position separated from the valve seat 26 by gravity as shown in the figure. The ball 25 is attached to the vehicle body so as to be oriented so as to receive a force directed toward the valve seat 26 due to vehicle deceleration during braking. When used in an X-piped hydraulic brake system, the inlet boat 7 is connected to the wheel cylinder 84 of the right front wheel and one hydraulic outlet port F of the tandem master cylinder 85, and the inlet boat 18 is connected to the wheel cylinder 86 of the left front wheel. At the same time, the other hydraulic outlet boat of the tandem master cylinder 85 is connected, and the outlet port (8.17) is connected to the left and right rear wheel cylinders 87.88, respectively.

The figure shows a non-operating state, and when the master cylinder 85 is operated by depressing the brake pedal 89, the same value of master cylinder hydraulic pressure Pm is simultaneously output from both hydraulic pressure outlets of the master cylinder. These master cylinder hydraulic pressures Pm are always maintained as they are in the front wheel cylinders 84 and 86, and remain unchanged in the rear wheel cylinders 38).
From 1B, chamber 16, center hole of pulp holder 4, valve body 10
' and the gap between the valve seat 12', the chamber 14 and the boat 17, and then the rear wheel cylinder 87. Initially, it is supplied as is through the chamber 6, the hole ab, the blind hole 8a, the gap between the valve body lO and the valve seat 12, the chamber 6, and the boat 8. Therefore, the rear wheel brake fluid pressure Pr toward the rear wheel cylinders 87, 88 is initially equal to the master cylinder fluid pressure (front wheel brake fluid pressure) Pm, and increases with the characteristics shown by a-b in FIG.

The equation for balancing the force acting on the plunger 3 at this time is that the cross-sectional area of the end of the plunger 3 that fits into the retainer 2 is A2, and the spring 2 is
If the spring force of 2 is F, it is expressed by the following equation.

Pm-A2≦F When the master cylinder hydraulic pressure Pm increases due to further depression of the play pedal 89, the value of the upper-type square becomes larger, and the plunger 8 moves to the left in the figure against the spring 22.
The valve body 1O is moved toward the valve seat 12 by the spring 11, and finally the valve body 10 is seated on the valve seat 12, thereby self-closing. From this point on, the rear wheel brake fluid pressure Pr toward the wheel cylinder 87 is restricted from increasing as shown below, but the fluid pressure at this time, that is, the critical fluid pressure Ps□ (see Figure 2), is pm in the above equation. Substituting “81” into P = −−−−−−(i) 81 people.

It is expressed as

When the poppet valve body 10 self-closes, the master cylinder hydraulic pressure Pm is equal to
The force of m・(A, -A,) pushes the plunger 8 in the opposite direction, that is, to the right in the figure, and the rear wheel brake fluid pressure Pr in the chamber 6 does not reach the plunger 8, causing a force Pr in the left direction in the figure. −
Compete with A. Here, when the brake pedal 31) is further depressed so that Pm>Ps□, the force due to the mask cylinder hydraulic pressure Pm is applied to the plunger 8 along with the spring force F of the spring 22.
Move to the left in the figure and open the valve body 10 again. As a result, the rear wheel brake fluid pressure Pr toward the wheel cylinder 37 increases as the master cylinder fluid pressure Pm is replenished, but the valve body l
By opening O, the master cylinder hydraulic pressure Pm again pushes the plunger 3 to the left in the figure, and as a result, the valve body lO immediately closes itself. By repeating this action, the rear wheel brake fluid pressure Pr increases while being limited with respect to the increase in master cylinder fluid pressure.

During this period, that is, during "m>" 81, when finding the balance equation of the force acting on the plunger 2, as is clear from the above, PrA, = Pm(A□-A, )+F--
---(2), and from this formula, the wheel cylinder 87
The rear wheel brake fluid pressure Pr toward the rear wheel is expressed by the following equation.

As is clear from this equation, when Pm>Psl, the master cylinder hydraulic pressure Pr can be limited against an increase in the star cylinder hydraulic pressure, as shown by b-c in FIG.

On the other hand, the opening and closing of the valve body 10 due to the above-mentioned operation of the plunger 8 is directly transmitted to the valve body 10' via the free piston 13, and this valve body 10' also opens and closes simultaneously and in the same manner as the valve body 10. Therefore, it is controlled in the same manner as the rear wheel brake fluid pressure toward the wheel cylinder 88 and the rear wheel brake fluid pressure toward the wheel cylinder 87.

By the way, the master cylinder hydraulic pressure Pm from the boat 7 also reaches the pulp holder center hole 28a via the chamber 6, the communication boat 9, and the valve hole 24a. However, the poppet valve body 8
0 is closed as shown in the figure, the master cylinder hydraulic pressure Pm acts on the right end surface of the valve holder 28 in the figure,
This is moved to the left in the figure against the force of the spring 29. At this time, the valve holder 28 collides with the bottom of the hole if, and the poppet valve body 80
is brought to the open position against the spring 81, and the master cylinder hydraulic pressure Pm'&: is supplied to the containment chamber 19 via the liquid path 88.

However, at this time, the master cylinder III (pressure Pm) comes to act on both end surfaces of the valve holder 28, and as a result, the valve holder 28 is immediately pushed back by the spring 29, causing the poppet valve body 80 to self-close.

By repeating this action, the differential pressure valve 27 receives the same pressure at both ends of the valve holder 28 as A8, and the spring force of the spring 29 as F'.
Then, the hydraulic pressure Pf expressed by the following equation is the pressure in the containment chamber 19
is supplied to.

F' Pf = Pm - Stone As is clear from this equation, the spring 2 in the containment chamber 19
A constant value F'/A determined by the spring force F' of No. 9 and the pressure received at both ends of the pulp holder A8 is supplied.
When the master cylinder hydraulic pressure Pm changes over time as indicated by α in the figure, the supply pressure Pf to the containment chamber 19 becomes as indicated by δ in the figure, which delays the occurrence of vehicle deceleration even more than the conventional hydraulic pressure change γ. You can get close to it.

When the vehicle deceleration period reaches a certain value due to the above-mentioned braking, the G pole 25 is seated on the valve seat 2B due to this deceleration, the deceleration sensing valve GV is closed, and the master cylinder when the relevant - electric range speed is generated is From the hydraulic pressure Pm to the above constant value F'/
The hydraulic pressure Pf reduced by A8 is confined within the chamber 19. Therefore, to generate the same constant deceleration, the brake pedal depression force (15) (master cylinder hydraulic pressure Pm) required for this purpose increases as the weight of the vehicle increases, and therefore the containment pressure Pf corresponds to the weight of the vehicle. However, when the vehicle is light, such as when the vehicle is empty, the confinement pressure is not high enough to move the piston 18 to the right in the drawing against the spring 22° 2B, and the piston 18 remains in the position shown.

Therefore, the spring force of the spring 22 does not increase the brake fluid pressure Pr of both wheels, and due to the above action, the front and rear wheel brake force distribution characteristics approximate the ideal characteristics when the vehicle is empty, and become a-b-0 in FIG. This prevents the rear wheels from locking first.

By the way, in the present invention G, the hydraulic pressure toward the containment chamber 19 is not the master cylinder hydraulic pressure Pm itself, but is reduced by a certain value by the differential pressure valve z7.
The containment pressure P also increases due to the large delay in the onset of heavy vehicle deceleration during braking in an empty vehicle state.

does not become too high and compress the spring 22 via the piston 18, and as described above, accurate hydraulic pressure control can be obtained.

On the other hand, when the weight of the vehicle increases due to the loading of the vehicle, and the confinement pressure Pf in the chamber 19 increases (16), this confinement pressure causes the piston 18 to move further to the right in the figure as the vehicle weight increases, and the spring 22 is gradually compressed. Due to this, the spring force F of the spring 22 increases, and the critical fluid pressure determined as in equation (1) above increases to Ps□ in FIG. It is possible to control the rear wheel brake fluid pressure Pr determined by b1-07 in FIG. Therefore, in the loaded state, the front and rear wheel brake force distribution characteristics are close to ideal characteristics a-
b'-c' can be used to prevent the rear wheels from locking first.

Also during this hydraulic pressure control, in the present invention, the hydraulic pressure toward the containment chamber 19 is not the master cylinder hydraulic pressure Pm itself,
Assuming that this pressure is reduced by a certain value by the differential pressure valve 27, the containment pressure P corresponds to the delay in the onset of vehicle deceleration during braking in a loaded state, and corresponds accurately to the vehicle weight. Therefore, it is possible to obtain accurate hydraulic pressure control as described above, and it is possible to prevent the hydraulic pressure from deviating from the required characteristics as in the conventional case.

Thus, in the deceleration sensing type hydraulic pressure control valve of the present invention, the differential pressure valve 27 is inserted into the inlet hydraulic pressure (master cylinder hydraulic pressure) passage to the containment port 19 as described above, and thereby the inlet hydraulic pressure is always kept by a constant value. Since the hydraulic pressure Pf controlled to be low is supplied to the containment chamber 19, the containment pressure Pf is generated in response to the onset of vehicle deceleration ta'rt in response to an increase in the inlet hydraulic pressure. As explained in the explanation, the desired hydraulic pressure control can be accurately executed not only when the vehicle is empty but also when the vehicle is loaded. Therefore, compared to the conventional deceleration-sensing static pressure control valve that provides an orifice and a dummy stroke to accurately control the hydraulic pressure when the vehicle is empty, it lacks accuracy in controlling the hydraulic pressure when the vehicle is loaded. The deceleration-sensing hydraulic pressure control valve of the present invention can accurately control the desired hydraulic pressure for guns of any vehicle weight, and has great safety benefits.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional side view of the deceleration sensing type hydraulic pressure control valve of the present invention, Fig. 2 is an operational characteristic diagram of the same hydraulic pressure control valve, and Fig. 8 is a diagram showing the occurrence and development of vehicle deceleration in response to an increase in master cylinder hydraulic pressure. FIG. 1 is a diagram showing changes over time in the confinement pressure in the hydraulic control valve of the present invention and in the confinement pressure in the conventional hydraulic opening/opening valve. 1... Valve body CV... Control valve JV...
・Interlocking valve GV...Deceleration sensing valve 19
...Containment room 22...Control valve hydraulic pressure 1! IJ control spring 27...Differential pressure valve 28...Valve holder 29...Valve holder return spring 80...Poppet valve body 81...Poppet valve body self-closing spring 82...Valve seat if, 9. 24a', 26a, 38-... Inlet hydraulic passage to the containment chamber 0

Claims (1)

[Claims] t The now control valve responds to the artificial hydraulic pressure against the spring, limits this inlet hydraulic pressure and controls the outlet hydraulic pressure, and closes at a deceleration above a certain level to generate this constant deceleration. and a deceleration sensing valve that compresses the spring by an amount corresponding to the containment pressure by confining the inlet fluid pressure in the containment chamber when A deceleration sensing type hydraulic pressure control valve characterized in that a differential pressure valve is inserted into the opposite inlet hydraulic pressure passage to supply a hydraulic pressure controlled to be always lower than the inlet hydraulic pressure by a constant value to the containment chamber.