JPS5929551A - X-shaped piping type liquid pressure device for vehicle brake - Google Patents

Abstract

PURPOSE:To relieve the deflecting trend of a vehicle at a time when one system is in out of order by a method in which a liquid pressure control valve is provided in the piping for front sheel in X-shaped piping system and the liquid pressure of the front wheel brake in the other system is controlled to more than a certain pressure at the time when the pressure of one system is in out of order. CONSTITUTION:When two systems are normal, since the piston 50 of each piston valve in a liquid pressure control valve 34 is at inoperative position, the liquid pressures of liquid chambers 20 and 22 of a master cylinder 18 are transmitted through both valves 64 to left and right-handed front wheel brakes 10 and 12. In case where the pipes 30, 32, and 33 of one system are broken and the liquid pressure of the system is unable to rise, no liquid pressure exertion the liquid pressure chamber 76 of the left-handed piston valve. The liquid pressure of the liquid chamber 20 of the master cylinder 18 is transmitted through the liquid pressure chamber of the right-handed piston valve to the liquid chamber 74 of the left-handed piston valve and further to the left-handed front wheel brake 10 through the valve 64. When the liquid pressure reaches more than a certain one, the piston of the left-handed piston valve moves to an operative position and the valve 64 is closed. The braking force of the left-handed front brake 10 can therefore be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-piped hydraulic system for vehicle brakes, and more particularly to a hydraulic system characterized by hydraulic pressure control when one system fails.

The X-piped type hydraulic system is a brake system in which the hydraulic pressure generated in two mutually independent hydraulic chambers of a mask cylinder is connected to two systems of independent piping, each located on a diagonal of the vehicle. This is a hydraulic system that is transmitted to the left front wheel brake, the right rear wheel brake, and the right front wheel brake and the left rear wheel brake.

Therefore, when the l system is defective, that is, when one of the two hydraulic pressure systems becomes unable to raise the hydraulic pressure due to a broken pipe, etc., the vehicle will be braked. However, front wheel brakes and rear wheel brakes do not necessarily have the same braking force; for example, in automobiles, especially front engine/front drive cars, the braking force of the front wheel brakes is set to be considerably larger than that of the rear wheel brakes. Therefore, when the l system fails, the left and right braking forces become unbalanced. That is, the braking force on the side braked by the front wheel brakes is large, and the braking force on the side braked by the rear wheel brakes is small, resulting in a tendency for the vehicle to veer to the right or left.

The present invention has been made for the purpose of providing an X-piping type hydraulic device that can reduce the tendency of the vehicle to deflect when the L-system is defective. In the type brake hydraulic system, 2
In the front wheel piping section of the system piping, which transmits the hydraulic pressure of the mask cylinder to the left front wheel brake and right front wheel brake, respectively, when one of the two piping systems is unable to increase the hydraulic pressure, the other piping is connected. A hydraulic pressure control valve is provided which suppresses the hydraulic pressure transmitted to the front wheel brake to be lower than the hydraulic pressure of the mask cylinder at least above a certain hydraulic pressure.

In such a hydraulic system, when the hydraulic pressure in both systems rises normally, the hydraulic pressure control valve does not operate, and the hydraulic pressure in the mask cylinder is directly transmitted to both front axle brakes. When one system fails, the hydraulic pressure control valve prevents excessive hydraulic pressure from being supplied to the front wheel brakes of the normal system, and the tendency of the vehicle to deflect is reduced.

EMBODIMENT OF THE INVENTION Hereinafter, an embodiment in which the present invention is applied to a hydraulic brake for an automobile will be described based on the drawings.

In the figure, 2 and 4 are the left and right front wheels of a front engine/front drive type vehicle, respectively, and 6 and 8
These are the left and right rear wheels respectively. Each of these wheels is provided with a brake 10, 12, 14, 16, respectively, and is actuated by hydraulic pressure generated in each brake brake cylinder 18. The master cylinder 18 includes two hydraulic pressure chambers 20 and 22, and generates hydraulic pressure corresponding to depression of a brake pedal 24 as a brake operating device. The hydraulic pressure generated in the hydraulic pressure chamber 2o is transmitted to the right rear wheel brake 16 through a pipe 26, while the left front wheel brake 1 is transmitted through pipes 28 and 29.
0. The hydraulic pressure in the hydraulic pressure chamber 22 is controlled by the piping 80. ．．
92.33 are transmitted to the left rear wheel brake 14 and the right front wheel brake 12, respectively. That is, the piping 26
．． 28 and 29 constitute one system, and piping 30, 32 and 33 constitute a separate system, and these two piping systems provide independent brakes for the wheels located diagonally on the vehicle. It is an X-piped hydraulic device that transmits hydraulic pressure.

The pipings 28 and 29 and the pipings 32 and 33 each constitute a front wheel piping portion of an independent system of piping, and a hydraulic pressure control valve 34 is disposed in the middle of these pipings. This hydraulic pressure control valve 34 has two proportioning valves, which are a type of hydraulic pressure control valve conventionally used for controlling the hydraulic pressure of rear wheel brakes, built into one housing. This housing includes a housing main body 36 having two stepped through holes formed parallel to each other, two ring-shaped partition members 38 fitted in each through hole, and one end of each through hole. It consists of two plugs 42 screwed together. Each partition member 38 is pressed and fixed against a stepped surface 46 of the housing body 36 by a plug 42, and is maintained liquid-tight with the housing body 36 by an O-ring 48. A piston 50 is also slidably inserted into the partition member 38, and the partition member 38 and the piston 50 are kept liquid-tight by an O-ring 52. The piston 50 has a flange 54 and a neck 56 . It includes a valve portion 58 and a head 60.

The head 60 has a slightly larger diameter than the valve portion 58, and is slidably fitted into a through hole formed in the housing body 36. Further, the valve portion 58 has a slightly larger diameter than the neck portion 56;
Together with a cup 62 fitted to the neck portion 56 with an annular gap in between, an on-off valve 64 is configured. In addition, the flange 54
serves not only to hold the cup 62 in a position close to the stepped surface 66 but also to serve as a spring holder for supporting one end of the compression coil spring 68. The other end of the compression coil spring 68 is supported by the partition member 38, and the spring 68 urges the piston 50 so that its head 60 comes into contact with the stepped surface 70.

When the head 60 is in contact with the stepped surface 70,
The valve portion 58 is separated from the cup 62 and the on-off valve 64 is in an open state. This position is referred to as the non-operating position of the piston 50.

By assembling each member as described above, the inside of the through hole is divided into three hydraulic pressure chambers.

That is, the first i pressure chamber 72 and the second hydraulic pressure chamber 74 are formed with the on-off valve 64 as a boundary, and the second hydraulic pressure chamber 74 is partitioned by the partition member 38 to form the third hydraulic pressure chamber 76. be.

The piping 29 is connected to the connection boat 78 of the 1st pressure chamber 72 of the proportioning pulp on the left, and the 1st 2nd hydraulic pressure chamber 74 is connected to the 3rd hydraulic pressure chamber of the proportioning pulp on the right through a communication passage 8o. 76, and this first i
A pipe 28 is connected to a connection port 82 of the pressure chamber 72 . Note that the piping 33 is connected to the connection boat 78 of the first hydraulic pressure chamber 72 of the proportioning pulp on the right side, and the second hydraulic pressure chamber 74 is connected to the communication path 80. Left hand proportioning no.φ
The third hydraulic pressure chamber 76 of the loop, the piping 32 via the connection port 82
is communicated with.

The piston 50 is connected to the three hydraulic chambers 72, 74 and 76.
The hydraulic pressure in the third hydraulic chamber 76 always has a magnitude corresponding to the product of the cross-sectional area of the piston 50 and the hydraulic pressure with respect to the piston 5o, and In contrast, the hydraulic pressure in the first hydraulic pressure chamber 72 and the second hydraulic pressure chamber 74 is applied to the piston 50 when the on-off valve 64 is open and closed. have different effects on That is, when the on-off valve 64 is open, the hydraulic pressure in the second hydraulic pressure chamber 74 has no substantial effect on the piston 50, and the hydraulic pressure in the first hydraulic pressure chamber 72 acts on the piston 50. It has a size corresponding to the product of the cross-sectional area of Ash, on the other hand, on-off valve 64
In the closed state, the hydraulic pressure in the first hydraulic chamber 72 has a magnitude corresponding to the product of the cross-sectional area of the valve portion 58 and the hydraulic pressure in the first hydraulic chamber 72, and acts on the piston 50. The hydraulic pressure in the second hydraulic pressure chamber 74 is determined by the difference between the cross-sectional area of the valve portion 58 and the cross-sectional area of the piston 50. and piston 5
A force is applied that pushes 0 toward the non-acting position. For convenience, the surface that substantially effectively receives the hydraulic pressure in the first hydraulic pressure chamber 72 of the piston 50 when the on-off valve 64 is closed (having an area equal to the cross-sectional area of the valve portion 58) is referred to as a first pressure receiving surface. The surface that effectively receives the hydraulic pressure of the second hydraulic pressure chamber 74 (the surface that has an area corresponding to the difference between the cross-sectional area of the valve portion 58 and the cross-sectional area of the piston 50) is referred to as the second pressure-receiving surface, and the third The surface that effectively receives the hydraulic pressure of the hydraulic pressure chamber 76 (the surface that has an area corresponding to the cross-sectional area of the piston 50) will be referred to as a third pressure receiving surface.

In the hydraulic system configured as described above, when the brake pedal 24 is depressed while both systems are normal,
Hydraulic pressures of the same level are generated in the hydraulic chambers 20 and 22 of the mask cylinder 18 and are transmitted to the rear wheel brakes 16 and 14, respectively, and to the hydraulic pressure control valve 34. In the hydraulic pressure control valve 34, both the left and right proportioning pulp pistons 50 are in the non-acting position, so the hydraulic pressure is applied to both the front width brakes 1 through the opening/closing valves 64.
0 and 12. At this time, the hydraulic pressure in the first hydraulic pressure chamber 72 tries to push the piston 50 toward the operating position, but the third i'? Since the hydraulic pressure in the N pressure chamber 76 has the same magnitude and tries to push the piston 50 with a force in the opposite direction, the forces acting on the piston 50 are eventually balanced, and the piston 50 is stopped by the biasing force of the spring 68. Do not move from the working position. In other words, the hydraulic pressure control valve 34 has no effect when both of the two systems are normal.

On the other hand, when the l system fails, for example, when one of the pipes 30, 32 and 33 is damaged and the hydraulic pressure in this system cannot rise, the front right wheel brake 12 and the rear left wheel brake 14 are It goes without saying that hydraulic pressure is not transmitted and these become inoperable, but at the same time, hydraulic pressure also ceases to act on the third hydraulic pressure chamber 76 of the left proportioning valve. On the other hand, hydraulic pressure is generated in the hydraulic pressure chamber 20 of the mask cylinder 18, which is transmitted to the right rear wheel brake 16, and is transmitted from the piping 28 to the third hydraulic pressure chamber 76 of the proportioning pulp on the right side to the proportioning pulp on the left side. 2nd g of Ningbarp! ! , to the pressure chamber 74, and further to the on-off valve 64.
．． It is transmitted to the left front wheel brake 10 via the first hydraulic chamber 72 and the piping 29. Therefore, the right rear wheel brake 16 and the left front wheel brake lo are operable, but the left front wheel brake 1
Since the pressure-receiving area of the wheel cylinder cylinder 0 is larger than that of the wheel cylinder of the right rear wheel brake 16, when the same level of hydraulic pressure is transmitted to both brakes, the pressure receiving area of the wheel cylinder 16 is larger than that of the wheel cylinder of the right rear wheel brake 16. The power will be greater than the braking force on the right side. If the difference in braking force is large, the vehicle will be deflected. In other words, there is a natural tendency for the vehicle to veer to the left as the vehicle brakes. However, in this embodiment, the hydraulic pressure control valve 34 starts the hydraulic pressure control operation and suppresses the braking force of the right front wheel brake 10 before a deflection that becomes a substantial problem occurs. That is, since no hydraulic pressure is acting on the third hydraulic pressure chamber 76 of the left proportioning valve as described above, the left proportioning valve was conventionally used to control the hydraulic pressure of the rear wheel brake. It operates in exactly the same way as a normal proportioning valve, reducing the mask cylinder hydraulic pressure at a fixed ratio and transmitting it to the left front wheel brake IO. However, when used for hydraulic pressure control of rear wheel brakes, the set load of the compression coil spring 68 is usually set relatively high.
In this embodiment, the set load on the spring 68 does not necessarily have to be as high as in conventional provisioning valves, but is simply set as large as necessary to hold the piston 50 in the non-actuating position. In some cases, the elastic force of the spring 68 can be almost ignored. In this case, the mask cylinder hydraulic pressure is reduced from the initial stage of braking and is transmitted to the left front wheel brake lO. The set load of which spring 68, together with the ratio of the first pressure receiving force and the second receiving pressure force of the piston 50, determines the hydraulic pressure control characteristics of the proportioning bar/l'7-. Brake 1
There is a huge difference in braking force between 0 and right rear wheel brake 16.
In other words, the braking force is determined so as not to cause a difference that would cause a substantial deflection of the vehicle, and yet to obtain as much braking force as possible for the vehicle as a whole.

The case where the system including the pipes 80, 82 and 33 fails has been described above, but the same effect can be obtained even when the opposite system fails.

On the wood flow side, two proportioning valves are provided in one housing, and the second and third hydraulic pressure chambers are communicated with each other by a communication passage, so that the joint Although this has the advantage of saving members and piping and reducing device costs, it is of course also possible to configure the two proportioning valves independently of each other.

Another embodiment of the invention is shown in FIG.

In this embodiment, two limit pulps 100 and 102 are used as bars, and as hydraulic pressure control valves.

The limit pulp valve 100 is equipped with a balance piston 106 that is slidably fitted into the housing body lO4, and this balance piston 106 is normally brought into contact with a retaining ring 110 by a compression coil spring 108.
In this state, the on-off valve 112 is kept open.

Therefore, the hydraulic pressure generated in the hydraulic pressure chamber 20 of the mask cylinder 18 is transferred to the piping 28, the on-off valve 112. It is transmitted to the left front wheel brake 10 via the hydraulic pressure chamber 114 and piping 29. On the other hand, °
The hydraulic pressure generated in the hydraulic chamber 22 is transmitted to the hydraulic chamber 118 of the limit pulp 100 through the pipe 116. Since the limit pulp 102 has a completely similar structure to the limit pulp 100, illustration and detailed description thereof will be omitted.

In the hydraulic system of this embodiment, if both systems are normal, the hydraulic pressure generated in the hydraulic pressure chambers 20 and 22 of the mask cylinder 18 is transmitted as is to each brake, but when one system fails, For example, when the system on the side of the liquid M chamber 22 of the mask cylinder 18 becomes unable to raise the liquid pressure, no liquid pressure acts on the liquid pressure chamber 118 of the limit pulp 100.
The hydraulic pressure in the hydraulic chamber 114 is increased until it overcomes the elastic force of the spring 1080! For example, the balance piston 106 is moved back toward the hydraulic pressure chamber 118, and the on-off valve 112 is closed. Therefore, the hydraulic pressure transmitted to the left front wheel brake IO does not increase any further, and substantially the same effect as in the previous embodiment can be obtained.

Although two typical embodiments of the present invention have been described above, the present invention may be implemented in other embodiments.

In other words, there are two hydraulic pressure control valves installed in the front wheel piping section.
If both pipes in the system are normal, no hydraulic pressure control operation is performed, and if the system fails, the hydraulic pressure in the normal system is kept lower than the mask cylinder hydraulic pressure at least above a certain level, and the front wheels are controlled. It can be adopted as long as it can be transmitted to the brakes, and the means for preventing the operation of the hydraulic pressure control valve when the two systems are normal can also be implemented by transmitting the hydraulic pressure of another system to the hydraulic pressure as in the above embodiment. It is possible to adopt not only one that directly acts on the piston of the control valve to prevent its operation, but also one that blocks the hydraulic control operation of the piston of the hydraulic control valve using a member such as a block piston.

Furthermore, in the above two embodiments, the piping that transmits the hydraulic pressure to the rear wheel brakes is not provided with a hydraulic pressure control valve, which has the advantage that the entire hydraulic system can be configured simply. It is also possible to use a control valve for controlling the hydraulic pressure transmitted to the wheel brakes.

Although not illustrated individually, it goes without saying that the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a hydraulic system for an automobile brake, which is an embodiment of the present invention. FIG. 2 is a circuit diagram showing another embodiment of the present invention. 10: Left front wheel brake 12: Right front wheel brake 14: Left rear wheel brake 16: Right rear wheel brake 18: Master cylinder 20, 22: M pressure chamber 26.28, 29.30, 3
2, 33: Piping 34: Hydraulic pressure control valve 36: Housing body 38: Partition member 50: Screws 1 to 58:
Valve part 62: Cup 64: Open/close valve 68: Compression coil spring 72: First hydraulic chamber 74: Second hydraulic chamber 76: Third hydraulic chamber 100, 102: Limit valve 104: Housing body 106: Balance piston 108 :Compression coil spring 112:Opening/closing valve 114,118:Hydraulic pressure chamber supplier Toyota Motor Corporation Fig. 1

Claims (1)

[Claims] (1) The hydraulic pressure generated in the two mutually independent hydraulic chambers of the mask cylinder is transmitted to the left front wheel brake and the right rear wheel of the vehicle through two mutually independent piping systems, respectively. In an X-piped brake hydraulic system that transmits to the brake, the right front wheel brake, and the left rear wheel brake, the hydraulic pressure of the mask cylinder of the two piping systems is transmitted to the left front wheel brake and the right front wheel brake, respectively. In the front wheel piping section, when the hydraulic pressure is unable to rise in one of the two piping systems and the hydraulic pressure transmitted to the front wheel brake by the other piping is at least above a certain hydraulic pressure, the hydraulic pressure of the master cylinder is increased. (2) The X-piped type vehicle brake is characterized by being provided with a hydraulic pressure control valve that suppresses the hydraulic pressure to a lower level. a housing comprising a second hydraulic chamber communicating with one hydraulic pressure chamber and a third hydraulic chamber communicating with the other hydraulic pressure chamber of the mask cylinder; and the first hydraulic chamber and the second hydraulic chamber. an on-off valve provided in a communication path with the housing, and is fluid-tightly fitted into the housing across the first to third hydraulic pressure chambers, is normally in a position where the on-off valve is opened, and is axially The on-off valve is closed by moving the on-off valve, and when the on-off valve is closed, the first pressure receiving surface is exposed to the first pressure receiving surface.
the hydraulic pressure in the hydraulic pressure chamber, the hydraulic pressure in the second hydraulic chamber to a second pressure receiving surface smaller than the first pressure receiving surface and in the opposite direction, and the third pressure receiving surface facing oppositely to the first pressure receiving surface. and pistons each receiving the hydraulic pressure of the third hydraulic pressure chamber, and in a state where the hydraulic pressures of the two hydraulic pressure chambers of the mask cylinder both rise normally, the piston is in a position where the opening/closing valve is opened. This allows the hydraulic pressure in the mask cylinder to be transmitted as is to the front wheel brake, and prevents the hydraulic pressure in the hydraulic pressure chamber on the side of the mask cylinder connected to the third hydraulic pressure chamber from increasing. 2. The hydraulic system according to claim 1, wherein in a state in which the piston and the on-off valve operate, the hydraulic pressure in the mask cylinder is reduced and transmitted to the front wheel brake. (3) The hydraulic device according to claim 2, wherein the piston is biased by a spring toward a position where the on-off valve is opened. (4) The hydraulic pressure control valves of the two front wheel piping sections are incorporated in one housing, and each second hydraulic chamber of both hydraulic pressure control valves and the third hydraulic pressure chamber of the other hydraulic pressure control valve A hydraulic device according to claim 2 or 3, which is in communication with a pressure chamber.