JPS6153262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in deceleration sensing valves used in hydraulic brake systems for automobiles and the like.

A car's hydraulic brake system brakes the front and rear wheels simultaneously, but if the rear wheels lock up first, the car will experience a sway phenomenon called skid, which is far more dangerous than if the front wheels locked up. be. Therefore, when braking, the weight of the vehicle moves forward, so the rear wheel load decreases and the rear wheels lock more easily than the front wheels. A hydraulic pressure control valve that limits the increase in wheel brake fluid pressure is inserted into the rear brake system.

The deceleration sensing valve (hereinafter referred to as G valve) according to the present invention can be used alone as this type of hydraulic pressure control valve, or in combination with a proportioning valve (hereinafter referred to as P valve) to control the above hydraulic pressure. Used to construct valves. by the way,
G valves are generally installed at an angle with respect to the horizontal line in the direction of vehicle travel, and include a ball that moves toward the valve seat in response to vehicle deceleration exceeding a certain level. No more inlet hydraulic pressure on the downstream side of the seat (master cylinder hydraulic pressure)
is configured so that it is not supplied. However, in the conventional G valve (for example, Japanese Patent Application Laid-Open No. 52-132276), the ball seats on the valve seat only after it has moved a certain full stroke, and the rise in hydraulic pressure on the downstream side is stopped. This movement takes place in the brake fluid, which provides resistance.
Since its movement speed is not greatly affected by the rising speed of vehicle deceleration and is almost constant, when the pressure increase speed of the inlet hydraulic pressure (master cylinder hydraulic pressure) is fast, the movement of the ball, that is, this ball The timing of sitting on the valve seat seems to be delayed. For this reason, in the conventional G valve, when the master cylinder hydraulic pressure increases at high speed, the hydraulic pressure downstream of the valve seat becomes too high, making it impossible to reliably achieve the purpose of preventing the rear wheels from locking. It was hot.

In view of the above, the present invention utilizes the energy of the brake fluid flow to promote the movement of the ball toward the valve seat only when the inlet hydraulic pressure is rapidly increasing. The G valve has been improved to operate ideally by making the speed correspond to the rate of increase in the hydraulic pressure generated on the downstream side of the valve seat.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an example of a hydraulic control valve constructed by combining the deceleration sensing type valve (G valve) of the present invention with a P valve. It goes without saying that the G-valve of the present invention can be used alone as a hydraulic pressure control valve with its configuration unchanged; however, in this specification, the G-valve of the present invention will be explained using the hydraulic pressure control valve shown in FIG. Expand the explanation.

In FIG. 1, reference numeral 1 indicates the main body of the hydraulic pressure control valve, and a normal P valve P and a G valve G of the present invention are built into this main body. For this purpose, a large diameter hole 1a and a small diameter blind hole 1b connected to this hole are provided in the main body 1.
A blind hole 1c is formed parallel to this blind hole, and a P valve P is housed in the holes 1a and 1b, and a G valve G is housed in the hole 1c.

P-valve P has the following configuration. That is, blind hole 1b
A retainer 2 is fitted to the open end of the retainer 2, and the plunger 3 is fitted into the blind hole 1b under the guidance of this retainer, thereby dividing the inside of the blind hole 1b into two chambers 4 and 5. The chamber 4 is isolated from the hole 1a by a seal 6 and communicated with the hole 1c by a port 7, and a hydraulic outlet port 8 provided in the main body 1 is opened in the chamber 5.

A blind hole 3a is provided in the end face of the plunger 3 facing the chamber 5, and a poppet valve body 10 biased in the valve closing direction by a spring 9 is disposed within the blind hole. is made to protrude from the open end of the blind hole 3a and is fixed to this open end. In addition, valve body 1
0 valve stem 10a is closer to the blind hole 1 than the valve seat 11 when the valve is closed.
The length should be such that it slightly protrudes toward the end wall of b.

The open end of the hole 1a is closed with an end cover 12, and the inner end surface thereof is opened to form a blind hole 12a. Blind hole 12a
A piston 13 is slidably fitted therein to define a chamber 14, and radial holes 15, 1 are connected to the chamber 14.
6 is formed on the end cap 12. An air bleed valve 17 communicating with the radial hole 15 is screwed onto the main body 1, and a liquid passage 18 communicating with the radial hole 16 and opening into the hole 1c is provided in the main body 1.

A spring seat 19 is provided on the end surface of the piston 13 facing the hole 1a.
and the spring actuator 20 is integrally provided. A plunger 3 protrudes into the hole 1a.
Two spring seats 21 and 22 are provided axially apart from each other at the end of the spring seat 21, and the spring seat 21 is locked to the shoulder portion 3d, and the spring seat 22 can be stroked along the small diameter portion 3c by the length thereof. Do it like this. A spring 23 is placed between spring seats 21 and 22, and a spring 24 is placed between spring seats 19 and 21.
are compressed, respectively, and a spring 25 is compressed between the end wall of the hole 1a and the spring seat 19.

The G valve G of the present invention is constructed as follows. The open end of the blind hole 1c is sealed with a plug 26, and a cylindrical ball holder 27 with one end closed is coaxially pressed against the bottom wall of the blind hole 1c. The ball holder 27 is arranged with an annular space between it and the peripheral wall of the blind hole 1c.
The inside of c is divided into two chambers 28 and 29. Liquid path 18
is opened into the chamber 28 at the bottom wall of the blind hole 1c,
A ball valve seat 30 is fixedly installed in this opening. The G ball 31 is slidably and tightly fitted into the ball holder 27, and the chambers formed before and after the ball 31 are communicated with each other by a vertical groove 27c formed on the inner peripheral surface of the ball holder 27, and the chamber 28 is A small hole 27a communicating with the chamber 29 is provided in the peripheral wall of the ball holder 27.
The ball holder 27 is further provided with a central through hole 27b in the closed end wall far from the valve seat 30, and a blind hole 26a connected to this through hole and a radial hole 26b communicating with the chamber 29 are formed in the plug 26. Further, a hydraulic inlet port 32 is formed in the main body 1 by opening into the chamber 29.

A rubber valve 3 is installed at the communication part between the through hole 27b and the blind hole 26b.
3 is mounted horizontally, and this rubber valve has the configuration shown in FIG. That is, the rubber valve 33 is entirely formed into a disk shape, and a rib 33a is raised in one direction on the periphery of the disk and is integrally provided. In the center of the rubber valve 33, a valve hole 33c, which is surrounded by ribs 33b protruding on both sides for the purpose of reinforcement, is usually formed with an extremely small diameter as shown in FIG. 2a. When a large pressure difference occurs between the front and rear sides of the valve hole 33c, the degree of opening increases according to the pressure difference as shown in FIG. , will not be ruptured.

The rib 33a of the rubber valve 33 is fitted into an annular groove 27b formed in the ball holder 27 so as to be concentric with the through hole 27b, and the outer peripheral edge is sandwiched between the abutting surfaces of the plug 26 and the ball holder 27. and install it. In this installed state, the rubber valve 33
passes through the valve hole 33c to the blind hole 26a and the through hole 27.
The two are isolated except for a small opening area between them.

In the hydraulic control valve which is a combination of the G valve G of the present invention and the ordinary P valve P as described above, the ball 31 normally comes into contact with the closing wall at one end of the ball holder 27 due to gravity as shown in FIG. It is arranged so as to be inclined with respect to the horizontal plane H so as to be away from the valve seat 30.
Specifically, as shown in FIG. 3, the hydraulic control valve V is oriented so that the ball 31 moves toward the valve seat 30 in response to vehicle deceleration, and is tilted by θ with respect to the horizontal line H' in the vehicle traveling direction. Attach to. and,
Similarly, as shown in FIG. 3, the hydraulic control valve V connects its port 8 to the wheel cylinders 34, 3 of the left and right rear wheels.
5, the ports 32 are connected to one hydraulic outlet of the master cylinder 36 for practical use. Note that the master cylinder 36 is connected to the brake pedal 37.
is activated by depressing the master cylinder 36.
The other hydraulic pressure outlet is connected to the wheel cylinders 38 and 39 of the left and right front wheels.

The operation of the hydraulic pressure control valve configured as described above will be explained next.

Normally, the ball 31 is separated from the valve seat 30 as described above, and the liquid passage 18 and the chamber 28 are in communication, and the plunger 3 and the spring seat 19 are kept at the farthest position by the springs 24 and 25, and the valve body 10 is pushed into the closed position with its valve stem 10a pushed in by the bottom wall of the blind hole 1b, and the spring seat 19 is pushed into the end cover 12.
I'm being pressured by Here, when the master cylinder 36 outputs hydraulic pressure Pm due to the operation of the brake pedal 37, this master cylinder hydraulic pressure Pm is directly transmitted to the front wheel cylinders 38 and 39, and is transmitted to the rear wheel cylinders 34 and 35 from the port 32. It is supplied through the chamber 29, the port 7, the chamber 4, the small hole 3b opened in the blind hole 3a and provided in the plunger 3, the gap between the valve body 10 and the valve seat 11, the chamber 5, and the port 8, respectively. Therefore, rear wheel brake fluid pressure Pr
is front wheel brake fluid pressure (master cylinder fluid pressure)
Pm, and the rear wheel brake fluid pressure Pr increases with the characteristics shown by a-b in FIG. The balance equation of the force acting on the plunger 3 at this time is the retainer 2
When the cross-sectional area of the inner hole is A ₂ and the spring force is F ₁ , it is expressed by the following equation.

Pm・A ₂ = F ₁ When the master cylinder hydraulic pressure Pm further increases by depressing the brake pedal 37, the value of the left term in the above equation increases, and the plunger 3 resists the spring 24 and moves to the left in FIG. The valve body 10 finally reaches a closed position where the valve body 10 is seated on the valve seat 11. The hydraulic pressure at this time, that is, the critical hydraulic pressure Ps, is expressed as Ps=F ₁ /A ₂ (1) by substituting Ps for Pm in the above equation. Then, the master cylinder hydraulic pressure
When Pm further increases as _the brake pedal 37 is depressed, this hydraulic pressure moves _the plunger ₃ to the right in FIG. When the valve body 10 is opened, the hydraulic pressure Pm is supplied to the port 8, and the rear wheel brake hydraulic pressure Pr also increases accordingly. here,
When Pm≧Ps, the balance equation of the force acting on the plunger 3 is found as follows: PrA ₁ = Pm (A ₁ − A ₂ ) + F ₁ …(2) From this equation, the rear wheel brake fluid pressure Pr can be calculated as follows: It is expressed as

Pr= _A1 - _A2 / _A1Pm + _F1 / _A1 =QPm+ _F1 /
A ₁ ...(3) (However, Q = A ₁ - _{A 2} /A ₁ ) As is clear from the above equation, the master cylinder hydraulic pressure
When Pm exceeds the critical hydraulic pressure Ps, the rear wheel brake hydraulic pressure Pr rises at a gradient m smaller than the previous rising gradient 1, as shown by b-c in Fig. 6, to prevent the rear wheels from locking. can.

On the other hand, the master cylinder hydraulic pressure Pm supplied to the port 32 causes the ball 31 to move toward the valve seat 3 as described above.
Since the central opening of 0 is not blocked, chambers 29, 2
8. It is also supplied to the chamber 14 via the liquid path 18.
By the way, when the master cylinder hydraulic pressure Pm increases, the vehicle braking force B also increases, and the deceleration ratio α obtained by dividing this braking force by the vehicle weight W also increases, as is clear from the following equation.

B=C・Pm (However, C is a constant) α/g=B/W ...(4) *g: A constant value in which the gravitational acceleration/deceleration ratio α/g is determined by the hydraulic control valve inclination angle θ (α/g) ₀ = f(θ) When the function of f(θ):θ is reached, the ball 31 resists the component of the acceleration of gravity in the direction of the inclination angle θ due to its inertial force, and moves toward the left in Fig. 1. and close the center opening of the valve seat 30. Therefore, even if the master cylinder hydraulic pressure Pm increases further, the hydraulic pressure acting on the piston 13 will be reduced by the ball 3.
1 closes the center opening of the valve seat 30, and the confinement pressure P _G in the chamber 14 at this time is expressed by the following equation from the above.

P _G =f(θ)/CW...( ₅ ) The force pushing the piston ₁₃ to the right in FIG. F ₁ and spring force F ₂ of spring 25
is balanced with the force expressed by the sum of F ₁ + F ₂ = P _G A ₃ = f(θ)/CA ₃ W (6), but the spring force F ₁ moves the plunger 3 to the right in Fig. 1. The spring force F ₂ is received by the main body 1.

On the other hand, the spring forces F ₁ and F ₂ correspond to the set loads f ₁ and f ₂ of the springs 24 and 25 when Pm=0, respectively, and the piston 1
The above movement amount △x of 3 and the spring constant of springs 24 and 25
Since it is the addition of the value found by the product of K ₁ and K ₂ , the relational expression between F ₁ and F ₂ is as follows.

F ₂ = f ₂ + K ₂ /K ₁ (F ₁ − f ₁ ) ...(7) Therefore, from equations (6) and (7) is found. Therefore, when Pm<Ps, equation (8) is
Substituting into equation (1), And, when Pm≧Ps, substituting equation (8) into equation (3), becomes.

Here, by selecting f ₂ −K ₂ /K ₁ f ₁ >0, the seventh
A relationship between the critical hydraulic pressure Ps and the vehicle weight W as shown in the figure is obtained, and as the vehicle weight W increases, the critical hydraulic pressure Ps increases while increasing its ratio to the vehicle weight W.

In this way, as the vehicle's carrying load increases, the rear wheel brake fluid pressure Pr will increase in proportion to it, and the split point b shown in FIG. 6 will rise. The pressure increases with the characteristics shown by a-b'-c' in FIG. 6, and almost ideal rear wheel brake fluid pressure characteristics can be achieved. However, when the vehicle is at maximum load or when the front wheel brake system fails, the brake pedal 37 must be depressed with even greater force to obtain the same constant braking force, so the containment pressure P _G increases. Although the stroke of the piston 13 increases accordingly, and the spring force of the spring 24 acting on the plunger 3 increases, the critical hydraulic pressure Ps that increases due to this is too low and the ideal brake force distribution characteristic cannot be obtained. With the illustrated hydraulic pressure control valve, the critical hydraulic pressure can be further increased when the vehicle is at maximum load or when the front wheel system is lost in the following manner.

That is, in the illustrated hydraulic control valve, at this time, the piston 13 pushes the spring seat 22 toward the retainer 2 via the spring actuator 20, thereby bending the spring 23. The spring force F ₃ of the spring 23 acts on the plunger 3 together with the spring force F ₁ of the spring 24, and the above equation (1) is replaced with Ps=F ₁ +F ₃ /A ₂ ...(11), and the above (3 ) formula is replaced by Pr=QPm+F ₁ +F ₃ /A ₁ (12).

Also, the above equation (6) can be replaced with the following equation.

F ₁ +F ₂ +F ₃ = f(θ)/CA ₃ W This equation and the above equation (7) correspond to the above equation (8) is found, and by substituting this equation into equations (11) and (12), Pm
<When Ps So, when Pm≧Ps becomes.

As is clear from the comparison between this equation and the above equation (10), when the piston 13 bends the spring 23 at maximum load or when the front wheel brake system fails, the critical fluid pressure increases when the car is empty or when the car is half loaded. The critical hydraulic pressure is increased at a rate even greater than the above ratio, and the rear wheel brake hydraulic pressure Pr reaches the split point as shown by a-b''-c'' in Figure 6.
b'' is raised at a sufficiently high position, making it possible to achieve ideal rear wheel brake fluid pressure characteristics.

By the way, during the above operation, the G valve G of the present invention functions as follows, and generates the speed of the ball 31 moving toward the valve seat 30 due to vehicle deceleration in the downstream side of the valve seat 30, that is, in the chamber 14. It can be made to correspond to the rising speed of hydraulic pressure. That is, at a low pressure increase rate of the master cylinder hydraulic pressure Pm where the movement of the ball 31 is not delayed, even if the master cylinder hydraulic pressure does not pass through the valve hole 33c of the rubber valve 33, which has a large resistance, it passes through the through hole 27a. Most of the G-valve can reach the chamber 14, and the G-valve of the present invention functions like a conventional G-valve, in which a master cylinder hydraulic pressure that corresponds precisely to the constant vehicle deceleration is contained, The containment pressure P _G corresponds to the constant vehicle deceleration mentioned above. However, when the master cylinder hydraulic pressure Pm is rising at a high rate, it cannot pass through the through hole 27a without resistance, and the chamber 29 becomes the chamber 28.
The higher pressure creates a differential pressure between these chambers. This differential pressure causes the rubber valve 33 to elastically deform in the corresponding direction at the center surrounded by the holes 26a and 27b, while changing the valve hole 33c of the rubber valve 33 from the normal state shown in FIG. 2a to the state shown in FIG. 2b. The brake fluid in the chamber 29 also flows into the chamber 28 from the valve hole 33c through the radial hole 26b and the blind hole 26a. The kinetic energy of the brake fluid flowing through the valve hole 33c acts on the ball 31 and helps the ball move toward the valve seat 30. Therefore, when the master cylinder hydraulic pressure Pm increases at a high rate, as described above, This solves the problem that the movement of the ball 31 tends to be delayed. Therefore, in the G valve of the present invention, even when the master cylinder hydraulic pressure Pm is at a high rate of increase, the movement speed of the ball 31 can be made to correspond to the rate of increase of the master cylinder hydraulic pressure, and the containment in the chamber 14 is improved. The pressure P _G can be set to a value corresponding to the weight of the vehicle at any rate of increase in master cylinder fluid pressure.

Note that the rubber valve 33 may have a shape without the reinforcing rib 33b (see FIGS. 1 and 2) as shown in FIG. 4, but in this case, the opening edge of the through hole 27b on the rubber valve 33 side is The rounded opening edge receives the peripheral edge surrounding the valve hole 33c of the rubber valve 33 when it is deformed from the normal state shown in FIG. 4a to the valve hole 33c as shown in FIG. 4b. This avoids the inconvenience in which the object of the present invention cannot be achieved due to excessively large opening area of 33c.

Moreover, in the present invention, instead of the rubber valve 33,
A normally closed valve 43 consisting of a valve body 40, a valve seat 41 and a spring 42 shown in FIG. 5 can be used. This normally closed valve 43 has a valve seat 41 connected to a through hole 27 near the plug 26.
The valve body 40 is fixed to the open end of the valve 41 and biased by a spring 42 from the side of the ball 31 toward the valve seat 41. For this reason, the normally closed valve 43 is normally closed as shown in the figure, and when the hydraulic pressure in the chamber 29 becomes higher than the hydraulic pressure in the chamber 28 by more than a certain level when the master cylinder hydraulic pressure Pm increases at a high rate, the differential pressure between the two It functions to open according to the degree. Therefore, in the G valve of this example, as in the above-mentioned example, when the master cylinder hydraulic pressure increases at a high speed, the brake fluid flow energy from the through hole 27b accelerates the movement of the ball 31 to achieve the intended purpose. I can do it.

[Brief explanation of the drawing]

Figure 1 shows the deceleration sensing type valve of the present invention in a normal P
A vertical side view of a rear wheel brake hydraulic pressure control valve configured in combination with a valve, FIG. 2 is a plan view of a rubber valve used in the valve of the present invention, and FIG. 3 is an explanation of how to install the hydraulic pressure control valve shown in FIG. 1. Figure 4 is a cross-sectional view of the essential parts showing another example of the valve of the present invention, Figure 5 is a cross-sectional view of the main parts showing still another example of the valve of the present invention, and Figure 6 is the valve of the present invention and proportioning. FIG. 7 is a diagram showing the operating characteristics of the hydraulic pressure control valve that is a combination of valves, and is also a diagram showing the change in critical hydraulic pressure with respect to the vehicle weight. DESCRIPTION OF SYMBOLS 1...Body, 3...Plunger, 7...Communication port, 8...Hydraulic pressure outlet port, 10...Poppet valve body, 11...Valve seat, 12...End cover, 13...Piston, 17... ...Air bleed valve, 18...Liquid path, 19...Spring seat, 20...Spring actuator, 2
1, 22...Spring seat, 23-25...Spring, 26
...Plug, 27...Ball holder, 30...
Ball valve seat, 31... G ball, 32... Hydraulic pressure inlet port, 33... Rubber valve, 33a... Mounting rib, 33b... Reinforcement rib, 33c... Valve hole, 3
4, 35... Rear wheel cylinder, 36... Master cylinder, 37... Brake pedal, 3
8, 39...Front wheel cylinder, 43...Normally closed valve.

Claims (1)

[Scope of Claims] 1 Master cylinder hydraulic pressure is conducted to the wheel cylinder via a proportioning valve, and the master cylinder is connected via a deceleration sensing valve to a containment chamber that changes the critical hydraulic pressure of the proportioning valve. A hydraulic pressure control valve that conducts cylinder hydraulic pressure includes: a ball holder that accommodates a G ball; a ball valve seat that is opened in the ball holder and communicates with the containment chamber; and a valve seat that is opposite to the ball valve seat with the G ball in between. a valve provided on the side of the ball holder, the valve opening increasing as the differential pressure between the master cylinder hydraulic pressure and the ball holder internal pressure increases to direct the master cylinder hydraulic pressure into the ball holder; and a small hole that guides the pressure into the ball holder and generates the pressure difference when the master cylinder hydraulic pressure increases at a high rate.