JPH0147336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration-responsive hydraulic pressure control valve used in a brake device for a vehicle or the like.

Conventionally, this type of deceleration-responsive hydraulic pressure control valve operates by applying the tension of a preload spring to a plunger.
a hydraulic pressure control section that opens and closes a valve according to the movement of the plunger and reduces the outlet pressure at a predetermined ratio to the inlet pressure within a range exceeding the pressure determined by the tension of the preload spring; A deceleration-responsive valve part that closes when a deceleration occurs, a control pressure is introduced into the control chamber through the deceleration-responsive valve part, and this control pressure is applied to the preload spring through a control piston to preload the spring. Some devices are known that include a control section that can change the tension of the load spring.

However, in such conventional devices, the control chamber is provided to contain the hydraulic pressure introduced via the deceleration response valve and apply it to the control piston, so when viewed from the overall piping system, the master cylinder The control valve branches off from the piping that connects the wheel cylinder and is at a dead end position, and when the control valve is installed on the actual vehicle and air is removed from the piping system and filled with hydraulic fluid, a large amount of air is generated in the control chamber. There is a problem that remains.

For this reason, a well-known bleeder device for air venting is installed in the control room, but when such a device is installed, it is possible to reliably bleed air from inside the control room. However, there is a problem in that the number of man-hours required to install the entire valve on an actual vehicle increases and the work efficiency decreases.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a deceleration-responsive hydraulic pressure control valve that makes it possible to easily and reliably bleed air from a control room. In addition, a passage is formed that connects the control chamber to the inlet or the outlet, and the passage is provided with a check valve that prevents liquid from moving from the inlet or the outlet toward the control chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The deceleration responsive hydraulic pressure control valve of the present invention will be described in detail below with reference to illustrated embodiments.

FIG. 1 is a side sectional view of a deceleration responsive hydraulic pressure control valve according to an embodiment of the present invention.

In the figure, the deceleration-responsive hydraulic pressure control valve is indicated as 1 as a whole, and the valve 1 has a stepped hole 5 having holes 2, 3, and 4 whose diameters become sequentially larger toward the left opening end. The main body 10 has a stepped hole 9 having holes 6, 7, and 8 whose diameters gradually increase toward the right opening end and are bored in communication with each other.

A control piston 14 is disposed within the stepped hole 5 such that the small diameter portion 11 is slidable in the hole 2, the medium diameter portion 12 is slid in the hole 3, and the large diameter portion 13 is slidable in the hole 4. There is a control chamber 15 in the hole 2, an outlet chamber 16 spanning the holes 2 and 3, an atmospheric chamber 17 on the hole 3 side of the hole 4, and an inlet chamber 18 in the center of the hole 4. Each is formed. The control piston 14 has a stepped hole 2 that opens toward the left and has a small diameter portion 19 and a large diameter portion 20.
1 is formed, and a plunger 25 is formed in which a large diameter part 22 is formed in the small diameter part 19 and a small diameter part 24 is slidably formed in the large diameter part 20 via a lid member 23 in the stepped hole 21. A second outlet chamber 2 is disposed in the small diameter portion 19 and communicates with the outlet chamber 16 through a through hole 26.
7 into the large diameter portion 20 through the through hole 28 into the inlet chamber 1
The medium diameter portion 30 between the large diameter portion 22 and the small diameter portion 24 is slidably fitted into the large diameter portion 20 with a bush 31 interposed therebetween. ing. The plunger 25 includes a second entrance chamber 2
A through hole 32 is formed which communicates between the valve spring 33 and the second outlet chamber 27.
The valve member 35 biased toward both chambers 27 and 29
They are arranged so that communication between them can be cut off.

Such control piston 14 and plunger 25
The first load spring 3 is supported at one end by a spring receiver 37 fixed to the main body 10 with a bolt 36 or the like.
8. The tension of the second load spring 39 is applied to each part separately. Note that 40 is a spring receiver that is disposed between the plunger 25 and the second load spring 39 and can restrict the movement of the plunger 25 and the control piston 14 below a predetermined value, and 41 is a spring receiver that is arranged between the plunger 25 and the second load spring 39 . Shows the spring receiver placed between.

On the other hand, the stepped hole 9 has a ball guide 4 in the hole 8.
A ball 43 is movably housed within the valve 2, and a valve seat member 44 is mounted in the holes 6 and 7 facing the ball 43. Valve seat member 44
The ball 43 is provided with a seat member 45 made of rubber on which the ball 43 is seated in a sealed manner, and a holding member 48 in which a central passage 47 having a diaphragm 46 is bored. The ball guide 42 has a lid member 49 screwed into the hole 8 and is supported with a cup-shaped member 50 interposed therebetween.

A through hole 52 from a connecting portion 51 to which piping from a master cylinder (not shown) is connected opens in the inlet chamber 18, and an axial passage 53 is formed from this through hole 52 to the stepped hole 9. , the passage 53 communicates with the control chamber 15 via the inside of the stepped hole 9, the hole 54 of the ball guide 42, the inside of the ball guide 42, and the central passage 47 in this order.

Further, the outlet chamber 16 is provided with a connecting portion 55 to which piping from a wheel cylinder of a rear wheel (not shown) is connected.
A through hole 56 is open. The connection part 55 is
The screw member 63 is screwed into a recess 57 provided on the side of the main body 10, and a stepped hole 58 that opens into the control chamber 54 is provided at the bottom of the recess 57. A ball 61 is provided which is biased by a valve spring 60 toward a rubber seat member 59 disposed in a large diameter portion of the valve 58 .

In addition, in the figure, 62 indicates a rotation stopper that fits into the passage 53 and prevents rotation of the ball guide 42, and a indicates a sealing member, and b
indicates a back-up spring for the sealing member a, and c indicates a stopper.

In the plunger 25 shown in the first figure, the effective pressure receiving area for the second outlet chamber 27 is larger than that for the second inlet chamber 29 by a predetermined ratio, which is different from conventional plungers of this type. It is similar. Moreover, the control piston 14 is
With the exception of the control chamber 15, the effective pressure-receiving area of each part is determined so that it will not move due to the hydraulic pressure acting on the left and right sides thereof.

The deceleration-responsive hydraulic pressure control valve 1 is designed so that the left side faces the direction of travel of the vehicle, and the left side is positioned upward and the right side is positioned downward.
It is installed on the vehicle body by tilting it.

In this embodiment, the hydraulic control valve section is composed of a plunger 25, a valve formed by a seat 34 in the plunger 25, a valve member 35, etc., a second load spring 39, and other members, and a deceleration responsive valve. The department is
It is composed of a ball 43, a valve seat member 44, and the like, and the control section is composed of a control chamber 15, a control piston 14, a plunger 25, and other members.

The operation of the valve 1 will be described below.

Assuming that the brake is not applied now, each member is in the illustrated position.

In other words, since the vehicle etc. is running at a constant speed,
The ball 43 is in contact with the cup-shaped member 50, and the control chamber 15 is in contact with the central passage 47 and the ball guide 42.
4 to the master cylinder, and the control piston 14 and plunger 25 communicate with the master cylinder through
Pressed by load springs 38 and 39, the right end of the control piston 14 contacts the step between the holes 2 and 6, and the right end of the plunger 25 contacts the control piston 1.
4, the valve member 35 is spaced from the seat 34, and the second inlet chamber 29 and second outlet chamber 27 communicate with each other.

When the brake is applied in this state and pressure is transmitted from the master cylinder, if the pressure is low, the pressure will be transferred to the inlet chamber 18, the second inlet chamber 29, the through hole 32, the second outlet chamber 27, and the outlet chamber. The same pressure is transmitted to the wheel cylinder sequentially through 16,
The brakes start to apply. At this time, plunger 25
, the pressure of the second outlet chamber 27 acts on the right side of the medium diameter part 30, and the pressure of the second inlet chamber 29 acts on the difference in area between the medium diameter part 30 and the small diameter part 24, and as a result, the plunger 25 moves to the left side. However, since the pressure is low, and the force acting to move the leftward is the difference between the two directions, the second load spring 3
The plunger 25 remains in abutment against the control piston 14 since it is insufficient to compress the piston 9 alone. Further, the pressure of the second inlet chamber 29 acts on the control piston 14 in the left direction via the cover member 23 in an area equal to the difference in area between the medium diameter portion 30 and the small diameter portion 24 of the plunger 25. The pressure of the second outlet chamber 27 acts in the right direction on an area equal to the area of the medium diameter part 30, and also the control piston 14
The outlet chamber 2 is located in the difference area between the medium diameter part 22 and the small diameter part 11.
7 acts in the left direction, but the dimensions of each part are determined so that the acting forces that try to move the control piston 14 in the left and right directions are approximately balanced between the right and left sides. In this case, the control piston 14 does not move. However, the control room 15
Since the pressure on the master cylinder side is transmitted sequentially through the passage 53, the hole 54, and the central passage 47, the control piston 14 receives the pressure inside the control chamber 15 on the right side of the small diameter portion 11, and the first load It tries to move against the urging force of the spring 38 and the second load spring 39.

Assuming that there is no load on the vehicle, in other words, if the vehicle is empty, the pressure required to generate a predetermined deceleration after starting to apply the brakes is also low, and the pressure that is required to generate a predetermined deceleration after the start of braking is low. Since pressure is transmitted to the wheel cylinder of the rear wheel and via valve 1, the ball 43 is
Due to its penetrating force, it moves against the inclination θ, seats on the valve seat member 44, and prevents pressure exceeding the pressure when a predetermined deceleration occurs to be transmitted to the control chamber 14. , preventing the control piston 14 from moving. Therefore, when the load is empty, the control piston 14 does not move, so each load spring 38,
39 does not change, and the plunger 25
It is biased to the right by the same tension as when the load spring 39 is set.

At this time, when the pressure on the master cylinder side increases, the second
The pressure inside the outlet chamber 27 acts to move the plunger 25 to the left.
The pressure inside the second inlet chamber 29 acts on the difference in area between the small diameter portion 24 and the pressure in the second inlet chamber 29, and the acting force tries to move the plunger 25 to the right, and the second load spring 39 biases the plunger 25 to the right. The plunger 25 moves to the left to overcome the sum of the acting forces and seat the valve member 35 on the seat 34, and the communication between the second inlet chamber 29 and the second outlet chamber 27 is cut off. The pressure on the 27 side begins to be reduced at a predetermined rate compared to the pressure on the second inlet chamber 29 side.

This pressure reduction is achieved by moving the valve member 35 toward the seat so that the acting force that attempts to move the plunger 25 to the right is balanced with the acting force that attempts to move the plunger 25 to the left.
The decompression rate is determined by the specifications of the plunger 25, and the pressure at which the decompression starts is determined by the plunger 25.
It is determined by the specifications of and the biasing force of the second load spring 39 against the plunger 25. Incidentally, since such an effect has been well known, a detailed description thereof will be omitted.

Next, if the vehicle has a considerable load, for example, it is fully loaded, after the brakes start to be applied, the pressure that generates a predetermined deceleration increases until the ball 43 seats on the valve seat member 44. The pressure inside the control chamber 15 also becomes relatively high, and the force that tries to move the control piston 14 to the left overcomes the sum of the tensions of both load springs 38 and 39, and the control piston 14 moves to the first position. The load spring 38 is directly compressed, and the second load spring 39 is moved while being compressed via the plunger 25. Therefore, the plunger 25 receives a large biasing force from the second load spring 39 due to the movement of the control piston 14, and although the rate of pressure reduction does not change, the pressure at which the pressure reduction starts is increased by the increase in the tension of the second load spring 39. This results in high pressure.

In the above-described embodiment exhibiting such an effect, the following effects can be obtained.

That is, it is possible to introduce a hydraulic pressure approximately proportional to the total weight or loading capacity of the vehicle into the control chamber 15, and change the tension of the second load spring 39 in accordance with this hydraulic pressure. The pressure at which the pressure transmitted to the wheel cylinder starts to be reduced compared to the pressure on the master cylinder side can be changed according to the total weight of the vehicle, etc. or the load capacity, and the optimal pressure can be set to the rear wheel cylinder. can be communicated to.

Furthermore, if the brakes are suddenly applied when the vehicle is empty,
As the pressure within the inlet chamber 29 rises rapidly,
The pressure inside the ball guide 42 also rises rapidly, and the pressure inside the ball guide 42 is throttled into the control chamber 15.
The pressure in the control chamber 15 that is transmitted through the wheel cylinder 6 tends to rise more than necessary, but if the pressure in the control chamber 15 becomes higher than the pressure transmitted to the rear wheel cylinder, the ball 61 will move up and down. It separates from the seat member 59 due to the pressure difference acting on the control chamber 1.
The pressure in the control chamber 15 is released to the wheel cylinder side to prevent an unnecessarily high pressure increase in the control chamber 15, and the pressure transmitted to the wheel cylinder of the rear wheel is transferred through the plunger 25 to the master cylinder. Although it rises later than the cylinder side, the pressure released from the control chamber 15 can compensate for the delay to some extent, and when comparing the pressure between the front wheel side and the rear wheel side, the front wheel side increases. very high
This prevents the brake force distribution from being extremely low on the rear wheels, and allows the brake force distribution between the front and rear wheels to approach an appropriate value. In particular, if the brakes are suddenly applied when the load is empty, if the pressure in the control chamber 15 is higher than necessary when a predetermined deceleration occurs,
There is a risk that the pressure transmitted to the wheel cylinder of the rear wheel will become high and the rear wheel may lock up, but in the above embodiment, the pressure in the control chamber 15 can be prevented from increasing more than necessary, and the reliability can be improved. becomes excellent.

Additionally, if the front brake system fails and the brakes are applied only to the rear wheels, especially when the vehicle is fully loaded, a fairly high pressure must be transmitted to the rear wheel cylinders. Although the predetermined deceleration does not occur easily, the plunger 25 tries to reduce the pressure transmitted to the rear wheel cylinder by the force acting on the left and right sides of the plunger 25, and the second outlet chamber 27 and the outlet chamber 1
The pressure in the master cylinder becomes lower than the pressure in the second inlet chamber 29 and the inlet chamber 18, but at this time, the ball 61 from the control chamber 15 is separated from the seat member 59 so that the pressure on the master cylinder side becomes lower than the pressure on the rear wheel cylinder side. A sufficiently high pressure can be supplied to the wheel cylinder without reducing the pressure supplied to the wheel cylinder.

The work involved in installing such a valve 1 on an actual vehicle will be described below.

Usually, a wheel cylinder is equipped with a well-known bleeder device, which is a device that can communicate and shut off the inside of the piping system with the outside. This will be explained in relation to the device.

Assuming that the valve 1 is fixed to the body of an actual vehicle and the installation of piping, etc. is completed, the master cylinder is operated several times with the wheel cylinder bleeder device in the cutoff position, and the pressure fluid is passed from the connection part 51 to the inlet chamber. 18. Then, a part of the pressure liquid enters the inlet chamber 18,
The second inlet chamber 29, the through hole 32, the second outlet chamber 27, and the outlet chamber 16 are sequentially filled and flow out from the connection hole 55 to the wheel cylinder side, and on the other hand, the passage 5
3, hole 54, the ball flows into the id 42 and flows into the control chamber 15 through the central passage while compressing the air within the control chamber 15;

When the bleeder device is placed in the communicating position with a certain amount of pressure generated within the piping system in this manner, the air within the piping system is discharged to the outside through the bleeder device and is compressed within the control room 15. The pressure of the ball 61 on the wheel cylinder side decreases, and the throttle 46 acts as a resistance to the expansion of the air in the control chamber 15. By being delayed compared to the side, ball 6
1 is separated from the seat member 59 and flows out to the wheel cylinder side.

After the exhaust air from the bleeder device is exhausted, the bleeder device is placed in the shutoff position, pressure is generated in the piping system in the same manner as above, and the above operations are repeated. At this time, when most of the air in the piping system is exhausted to the outside, the pressure generated in the piping system becomes relatively high, and the pressure in the control chamber 15 moves the control piston 14 to the left to control the piping system. The volume of the chamber 15 is increased and more liquid is introduced into the control chamber 15. In this state, when the bleeder device is placed in the communication position, the pressure of the air remaining in the control chamber 15 is released from the throttle 46, but the pressure is released by the rightward movement of the control piston 14. As a result, the ball 61 is actively separated from the seat member 59, flows toward the wheel cylinder, and is finally discharged from the bleeder device to the outside.

In this way, in the above embodiment, in addition to the above-mentioned effects, when performing air purge work similar to the conventional one, instead of providing a bleeder device for the control chamber 15, liquid movement to the wheel cylinder side is performed. By providing a check valve that allows this, the air in the control chamber 15 can be reliably discharged.Furthermore, if a bleeder device is used, there is a risk of liquid leakage. In the above embodiment, valve 1
There is no liquid leakage to the outside of the valve 1, and the function of the valve 1 is not only achieved through reliable air venting, but also the valve 1
This improves reliability against liquid leakage.

FIG. 2 is a side sectional view showing essential parts of another embodiment of the invention. Note that in FIG. 2, members or portions having the same functions as those in FIG. 1 are given the same reference numerals and explanations will be omitted, and only particular differences will be explained.

The example shown in FIG. 2 is provided with a through hole 65 that communicates the control room 15 and the passage 53,
A check valve 66 is provided to allow liquid to move from the outlet chamber 16 to the passage 53, and a connecting portion 67 communicating with the outlet chamber 16 is provided independently in another portion.

Also in this example, the air in the control chamber 15 opens the check valve 66, flows out into the passage 53, and moves toward the inlet chamber 18 due to the inclination θ. Next, when the master cylinder is depressed again, it is moved to the wheel cylinder side through the inlet chamber 18, second inlet chamber 29, etc., and is discharged from the bleeder device to the outside.

As described above, various effects have been obtained in the above embodiments, but the present invention can be implemented without being limited to the above embodiments.

That is, in the above embodiment, the control piston 14
Although an example is shown in which the plunger 25 is installed inside the movable body, these two movable bodies may be of various conventionally known types.

As is clear from the above, in the present invention, a passage is formed that connects the control chamber to the inlet or the outlet, and a check valve is provided in the passage to prevent liquid from moving from the inlet or the outlet toward the control chamber. ,
The check valve can be opened by the pressure difference between the control chamber and the inlet or outlet, and when the check valve opens, the air in the control chamber is discharged, and the control chamber is sufficiently filled with liquid. This allows the entire valve to function reliably. Furthermore, since there is no need to provide a bleeder device to the control room, there is no fear of liquid leaking to the outside of the valve, and reliability against failure is high.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a deceleration responsive hydraulic pressure control valve which is one embodiment of the present invention, and FIG. 2 is a diagram showing another embodiment. DESCRIPTION OF SYMBOLS 1... Deceleration response hydraulic pressure control valve, 15... Control chamber, 16... Outlet chamber, 18... Inlet chamber, 27...
Second exit chamber, 29... Second entrance chamber, 57... Recess, 58... Stepped hole, 59... Seat member, 60...
Valve spring, 61... ball.

Claims (1)

[Claims] 1 Apply the tension of the preload spring to the plunger,
a hydraulic pressure control section that opens and closes a valve in accordance with the movement of the plunger and reduces outlet pressure at a predetermined rate compared to inlet pressure within a range exceeding the pressure determined by the tension of the preload spring; and a predetermined deceleration rate. a deceleration-responsive valve portion that closes when the deceleration-responsive valve portion occurs; control pressure is introduced into the control chamber through the deceleration-response valve portion; and this control pressure is applied to the preload spring through the control piston. In a deceleration-responsive hydraulic pressure control valve equipped with a control unit capable of changing the tension of a preload spring, a passage connecting the control chamber to an inlet or an outlet is formed, and a passage is connected to the control chamber from the inlet or outlet. A deceleration-responsive hydraulic pressure control valve equipped with a check valve that prevents liquid from moving toward.