JPH068960Y2 - Hydraulic brake device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic brake device for controlling the hydraulic pressure of a brake cylinder of a rear wheel, and in particular, anti-skid control is performed by using a proportioning valve. The present invention relates to a hydraulic brake device.

2. Description of the Related Art When a vehicle is braked, a load shifts from the rear side to the front side of the vehicle body, and the rear wheels easily slip. After the hydraulic pressure of the hydraulic pressure source reaches the set value, the hydraulic pressure is reduced at a constant ratio and supplied to the brake cylinder. In addition, an anti-skid device that controls the hydraulic pressure of the brake cylinder is also provided to prevent the wheel from locking due to excessive braking force.A proportioning valve is a type of this anti-skid device. Some are configured to be used. The hydraulic brake device described in Japanese Utility Model Laid-Open No. 61-82867 is an example.

This device is constructed as shown in FIG. A valve piston 200 of a proportioning valve of this hydraulic brake device includes a first piston 202 and a second piston 204 having a diameter larger than that of the first piston 202 and axially slidably fitted to the first piston 202. And the relative movement distance between the pistons 202 and 204 is defined by the engagement hole 206 and the connecting rod 208. The hydraulic pressure generated in the master cylinder 210 during braking is supplied to the first hydraulic chamber 214 that applies hydraulic pressure to the first pressure receiving surface 212 of the first piston 202, and the on-off valve opened by the second piston 204. 216, is supplied to the brake cylinder 224 of the rear wheel 222 through the second hydraulic chamber 220 in which the hydraulic pressure acts on the second pressure receiving surface 218 of the second piston 204.
After the hydraulic pressure of the master cylinder 210 reaches the set value, the first piston 202 and the second piston 204 move integrally in the direction against the biasing force of the spring 226 and the direction in which the opening / closing valve 216 is opened. As a result, the opening / closing of the on-off valve 216 is controlled, and the hydraulic pressure of the master cylinder 210 is reduced at a constant rate and supplied to the brake cylinder 224.

A control piston 230 is integrally provided on the first piston 202, and the control hydraulic chamber 23 is provided on the side opposite to the first hydraulic chamber 214.
2 is formed. The control fluid pressure chamber 232 is selectively connected to the accumulator 234 and the reservoir 235 by switching the electromagnetic directional control valve 233. When the slip of the rear wheel 222 exceeds the set value, the control hydraulic chamber 232
Since hydraulic pressure is supplied to the first accumulator 234 from the accumulator 234, the control piston 230 applies a control force to the first piston 202 in the direction opposite to the biasing force of the spring 226.
The first piston 202 moves integrally with the second piston 204 against the biasing force of the spring 226, and the opening / closing valve 216
Is closed and the volume of the second hydraulic chamber 220 is increased, and the brake fluid in the brake cylinder 224 is released from the second hydraulic chamber 220.
The inflow of the liquid reduces the hydraulic pressure, and the locking of the rear wheel 222 is avoided.

According to this hydraulic brake device, the anti-skid device can be simply configured. However, due to the occurrence of an abnormality in the control circuit or the like, hydraulic pressure is supplied to the control hydraulic chamber 232 during non-braking, or during braking. Even if the hydraulic pressure supplied to the control hydraulic chamber 232 becomes abnormally large, or if the volume of the second hydraulic chamber 220 becomes excessive, the second hydraulic chamber 2
The volume of 20 becomes excessive and a negative pressure is generated. for that reason,
The first piston 202 is provided with an opening / closing valve 236 that connects and disconnects the first hydraulic pressure chamber 214 and the second hydraulic pressure chamber 220,
The generation of negative pressure is avoided. The valve element 238 of the on-off valve 236 is always biased by the spring 240 and is seated on the valve seat 242 so that both the hydraulic chambers 214, 22 are exposed.
Although the communication of 0 is cut off, as described above, the control hydraulic chamber 2
When an abnormal hydraulic pressure is supplied to 32, the connecting rod 208 moves the connecting rod 208 along with the relative movement of the first piston 202 and the second piston 204 by the urging force of the spring 244.
6 is moved, the on-off valve 236 is opened, the hydraulic chamber 214 and the second hydraulic chamber 220 are made to communicate, and the generation of negative pressure in the second hydraulic chamber 220 is avoided.

However, in the hydraulic brake device described above, the valve piston 200 includes the first piston 202 and the second piston 204.
In addition to the above, there is a problem that the structure is complicated because the opening / closing valve 236 for preventing negative pressure is provided in the first piston 202, and the manufacturing cost increases.

Means for Solving the Problems In order to solve the above problems, the present invention provides (a) an undivided integral valve piston, an on-off valve (for pressure reduction control), a first hydraulic chamber, a second hydraulic chamber and A proportioning valve having a biasing means and (b) an anti-skid device having a control piston and a hydraulic pressure control device are provided, and the opening / closing valve is closed and the volume of the second hydraulic pressure chamber is increased to increase the volume of the rear wheel. In the type of hydraulic brake device that avoids the lock of
The valve piston and the control piston are separated from each other, and the urging means urges the control piston in a direction in which the control piston abuts against the valve piston so that the abutment force is applied to the valve piston. The pressure chamber causes the control piston to exert hydraulic pressure in a direction away from the valve piston.

Action In the hydraulic brake device configured as described above,
When the rear wheel slip is not excessive and normal braking is performed, hydraulic pressure is not supplied to the control hydraulic chamber, and the hydraulic pressure of the hydraulic pressure source is set by the urging force of the urging means. After reaching the hydraulic pressure, the valve piston and the control piston move integrally, and the proportioning valve reduces the hydraulic pressure of the hydraulic pressure source at a constant ratio and supplies it to the brake cylinder, similar to the conventional proportioning valve. To do.

However, if the rear wheel slips excessively, the hydraulic pressure in the control hydraulic chamber is increased, the control piston moves in a direction away from the valve piston, and the urging force of the urging means is reduced. It is allowed to move to one hydraulic chamber side. As a result, the volume of the second hydraulic chamber increases,
When the brake fluid in the brake cylinder flows into the second fluid pressure chamber, the fluid pressure is reduced, and the locking of the rear wheels is avoided.

In this way, the urging force of the urging means is reduced as the hydraulic pressure of the control hydraulic chamber is increased, and the volume of the second hydraulic chamber is increased.However, the control piston and the valve piston are separated from each other. Since the control piston is acted upon by hydraulic pressure in a direction away from the valve piston, a state occurs in which the control piston moves away from the valve piston and does not apply an urging force as the hydraulic pressure increases. Then, even if the hydraulic pressure in the control hydraulic chamber is further increased from this state, the control piston only moves and the valve piston is kept in a state in which it is not subjected to the biasing force. The volume of the second hydraulic chamber increases only up to the size in the state where the valve piston does not receive the urging force of the urging means, and the hydraulic pressure of the brake cylinder must be positive pressure within this range. Therefore, even if the hydraulic pressure is supplied to the control hydraulic chamber during non-braking or the hydraulic pressure in the control hydraulic chamber is abnormally increased during braking, the negative pressure is not generated in the brake cylinder.

As described above, according to the present invention, it is possible to avoid the generation of negative pressure, and the structure therefor is the above-mentioned No. 61-82.
Compared with the hydraulic brake device described in No. 867, it is simple and can be manufactured at low cost.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system diagram of a hydraulic brake device according to an embodiment of the present invention. In the figure, 10 is a brake pedal,
The pedal 10 operates a master cylinder 12, which is a hydraulic pressure source. The master cylinder 12 includes two pressurizing chambers 14 and 16 that are independent of each other, and generates a hydraulic pressure of the same height in each of the pressurizing chambers 14 and 16 based on the depression operation of the brake pedal 10. The hydraulic pressure generated in one pressurizing chamber 14 is provided to the left front wheel 18 and the right front wheel 20, respectively, and is supplied to the front wheel cylinders 20 and 24 of the brake. The hydraulic pressure generated in the other pressurizing chamber 16 is supplied to the rear wheel cylinders 30 and 32 of the brakes provided on the left rear wheel 26 and the right rear wheel 28, respectively. This hydraulic brake device has a front and rear two-system type.

Rear wheel cylinders 30, 32 for the left and right rear wheels 26, 28
The brake fluid supplied to the valve is controlled by the proportioning valve 36 and the antiskid device 38.

In the valve body 42 of the proportioning valve 36,
Large-diameter holes 44, 46 opening at both ends in the longitudinal direction are formed concentrically, and small-diameter holes 48 connecting the large-diameter holes 44, 46 are formed. Large diameter holes 44, 46
The respective openings are closed by plugs 50 and 52, respectively, and a valve piston 54 is axially slidably fitted in a portion of the small diameter hole 48 on the large diameter hole 44 side. The valve piston 54 has a stepped shape, and the small diameter portion 56 is liquid-tightly fitted in the small diameter hole 48, and the large diameter portion 58 is fitted in the bottomed hole 60 formed in the plug 50. There is. The large-diameter portion 58 communicates with the valve seat member 62 provided at the opening of the bottomed hole 60 so that the brake fluid flows from the master cylinder 12 to the rear wheel cylinders 30 and 32.
An on-off valve 64 for shutting off is formed.

The valve chamber formed by the valve main body 42 and the plug 50 has a port 66 and a liquid passage 6 at the opening / closing valve 64.
The first hydraulic pressure chamber 70 is connected to the master cylinder 12 by 8 and the second hydraulic pressure chamber 76 is connected to the rear wheel cylinders 30 and 32 by the port 72 and the liquid passage 74. The first hydraulic chamber 70 has a ring-shaped end surface (first pressure receiving surface) 78 formed by the large diameter portion 58 and the small diameter portion 56 of the valve piston 54 on the master cylinder 12.
Of the rear wheel cylinders 30, 32 on the end surface (second pressure receiving surface) 80 of the large diameter portion 58.
Apply the hydraulic pressure of.

On the other hand, a control piston 84 is arranged in the space formed by the large diameter hole 46. A part of the valve body 42 constitutes a cylinder. The control piston 84 has a stepped shape, and is fitted in the large diameter hole 46 in the large diameter portion 86 and in the small diameter hole 48 in the small diameter portion 88 in a liquid-tight and slidable manner. A control hydraulic chamber 90 is formed between the diameter portion 86 and the bottom surface of the large diameter hole 46, and a spring chamber 92 is formed between the control hydraulic chamber 90 and the plug 52. The spring chamber 92 is made to communicate with the atmosphere through an air hole 94 formed in the plug 52, and a spring 96 serving as a biasing means is disposed inside the spring chamber 92 so that the control piston 84 contacts the valve piston 54. Biasing, spring 9
A biasing force of 6 is applied to the valve piston 54.

As will be described later, the hydraulic pressure in the control hydraulic chamber 90 is set to be equal to the atmospheric pressure when the brake is not applied and when the anti-skid control is not performed, and the open / close valve 64 is always open. The hydraulic pressure generated in the pressurizing chamber 16 based on the depression of the brake pedal 10 causes the liquid passage 68,
It is supplied to the rear wheel cylinders 30, 32 through the port 66, the first hydraulic chamber 70, the opening / closing valve 64, the second hydraulic chamber 76, the port 72, and the liquid passage 74. When the hydraulic pressure of the master cylinder 12 reaches a set value (breaking point hydraulic pressure) determined by the spring 96, the valve piston 54 compresses the spring 96 and the large diameter portion 58 causes the valve seat member 62 to move.
Then, the opening / closing valve 64 is closed. However, if the hydraulic pressure in the master cylinder 12 becomes higher, the on-off valve 64 is opened again, and by opening and closing the on-off valve 64 based on the movement of the valve piston 54, the hydraulic pressure in the master cylinder 12 becomes the second pressure. As indicated by the solid line A in the figure, the rear wheel cylinder 3 is depressurized at a constant rate.
0,32. At this time, the control piston 8
4 moves integrally with the valve piston 54 to apply the biasing force of the spring 96 to the valve piston 54.

The control hydraulic chamber 90 communicates with the reservoir 102 by switching the electromagnetic directional control valve 100, and the accumulator 1
It is switched to the state of communicating with 04. In the accumulator 104, the brake fluid in the reservoir 102, which has been pumped up by the pump 106, is stored at about the set pressure of the relief valve 108. A rotation sensor 110 for detecting the rotation speed of each of the rear wheels 26, 28 is provided, and the control circuit 112 mainly composed of a computer includes the rotation sensor 1
The slip condition of the rear wheels 26 and 28 is detected based on the detection signal of the solenoid 10 and the solenoid 114 of the electromagnetic directional control valve 100 is detected.
Switch. The solenoid 114 is always demagnetized, and the control hydraulic chamber 90 is in communication with the reservoir 102.

When the slips of the rear wheels 26, 28 become excessive, the control circuit 112 excites the solenoid 114, and the control hydraulic chamber 90 is switched to the state of communicating with the accumulator 104. As a result, the hydraulic pressure in the control hydraulic chamber 90 is increased, and the control piston 84 retracts in the direction away from the valve piston 54 against the biasing force of the spring 96. The valve piston 54 is in a state of being seated on the valve seat member 62 at its large diameter portion 58, but the valve seat member 62 is made of rubber and is elastically deformable, so that the valve piston 54 has a leftward force in the drawing. Valve piston 5
4 moves in the force acting direction by the large diameter portion 58 of the valve 4 pushing the inner diameter of the valve seat member 62 and sliding it in. Therefore, as described above, if the control piston 84 retracts,
It is permissible to further retract from the retracted position in the case of performing the pressure reduction indicated by the solid line A in FIG. The backward movement of the valve piston 54 increases the volume of the second hydraulic chamber 76, allows the inflow of brake fluid from the rear wheel cylinders 30 and 32, and lowers the fluid pressure thereof.
Locks are avoided. In the present embodiment, the electromagnetic directional control valve 100, the reservoir 102, the accumulator 10
4, pump 106, rotation sensor 110, control circuit 112
Etc. constitute a hydraulic pressure control device. The retracted end of the control piston 84 has a protrusion 116 formed on the end face of the control piston 84 and a protrusion 11 formed on the plug 52.
Although the protrusions 116 and 118 are regulated by abutting against the valve piston 8, the protrusions 116 and 118 allow the control piston 84 to separate from the valve piston 54 and not to apply the biasing force of the spring 96 to the valve piston 54. Is formed.

When the hydraulic pressure in the control hydraulic chamber 90 is increased, the control piston 84 is separated from the valve piston 54 and the spring 9
The urging force of 6 is not applied to the valve piston 54. In this state, the proportioning valve 36 reduces the hydraulic pressure of the master cylinder 12 at a constant rate from the beginning of braking and supplies the hydraulic pressure to the rear wheel cylinders 30, 32, as shown by the chain double-dashed line B in FIG. It becomes a state. Then, even if the hydraulic pressure in the control hydraulic chamber 90 is further increased from this state, the valve piston 54 and the control piston 84 are separate bodies, and the control piston 84 is separated from the valve piston 54 in the control hydraulic chamber 90. Since the control hydraulic pressure is applied in the direction away from the valve piston 54,
Therefore, the proportioning valve 36 is kept in a state of being depressurized without receiving the biasing force of the spring 96. The anti-skid control is performed in the range shown by the diagonal lines in FIG.

If the valve piston 54 is retracted endlessly as the hydraulic pressure in the control hydraulic chamber 90 increases, the second hydraulic chamber 7
The volume of 6 is 0 when the hydraulic pressure of the rear wheel cylinders 30 and 32 is 0.
It further increases from the state of (atmospheric pressure), and the broken line C in FIG.
As shown by, negative pressure is generated in the rear wheel cylinders 30, 32. However, in this embodiment,
Since the valve piston 54 does not retreat from the retracted position in the state where the biasing force of the spring 96 is not received,
The volume of the second hydraulic pressure chamber 76 is equal to the rear wheel cylinders 30, 3
The pressure does not increase to a level that causes a negative pressure in 2 and is always controlled in the positive pressure range.

Therefore, due to some abnormality, hydraulic pressure is supplied to the control hydraulic pressure chamber 90 during non-braking, or the control hydraulic pressure chamber 90 is controlled during braking.
If the hydraulic pressure becomes excessively large, a negative pressure will not be generated in the rear wheel cylinders 30 and 32 even if a braking force slightly lower than the actually required braking force may be obtained.

Another embodiment of the present invention is shown in FIG. In this embodiment, the opening / closing valve 122 of the proportioning valve 120 is a poppet valve and is provided separately from the valve piston 124. Inside the valve body 126, large-diameter holes 128, 130, cylinder bores 132, large-diameter holes 13 opening at both end surfaces thereof.
0 and the cylinder bore 132 are concentrically formed with a small diameter hole 134, and the large diameter portion 13 of the valve piston 124 is formed.
6 is fitted in the cylinder bore 132, and the small diameter portion 138 is fitted in the small diameter hole 134 so as to be liquid-tight and slidable. The large-diameter hole 130 is closed by the plug 140 and the control piston 84 and the spring 96 are arranged, as in the large-diameter hole 52 of the above-described embodiment.
4 is brought into contact with the valve piston 124 to apply a biasing force. The configuration of the hydraulic control device is also the same,
Corresponding parts are designated by the same reference numerals to show the correspondence,
Detailed description is omitted.

By fitting the valve piston 124, the cylinder bore 132
Inside, there is a first hydraulic chamber 148 that causes the hydraulic pressure of the master cylinder 12 guided by the liquid passage 124 and the port 144 to act on the annular first pressure receiving surface 146 of the valve piston 124.
A second hydraulic chamber 156 is formed which causes the hydraulic pressure of the rear wheel cylinders 30, 32 guided by the liquid passage 150 and the port 152 to act on the end surface (second pressure receiving surface) 154 of the large diameter portion 136.

The opening of the large diameter hole 128 is closed by a plug 158 to form a valve chamber 160. The valve chamber 160 has a liquid passage 162
Is communicated with the second hydraulic chamber 156 by
Liquid passage 164 formed in plug 158, valve body 1
The fluid passage 166 formed in the first fluid pressure chamber 14
8, and the on-off valve 122 is provided in the valve chamber 160. The valve element 168 of the on-off valve 122 is the valve chamber 16
It is arranged movably in 0, and by the spring 170,
The valve is seated on the valve seat 172 and is urged in such a direction as to block the communication between the valve chamber 160 and the second hydraulic chamber 156. On-off valve 122
Is always integrally formed with the valve element 168,
The rod 174 inserted into the valve piston 2 is attached to the valve piston 1
It is pushed and kept open by 24, but after the hydraulic pressure of the master cylinder 12 reaches a set value during braking,
As the valve piston 124 moves against the biasing force of the spring 96, the valve element 162 is seated on the valve seat 172 and closed. Other operations and effects are the same as those in the above-mentioned embodiment, and detailed description thereof will be omitted.

The proportioning valves 36 and 120 described in each of the above embodiments can also be used as load-sensing proportioning valves. That is, a detection device for detecting the load of the rear wheels 26, 28 is provided, and the control circuit 112 is based on the detection result of the detection device.
Controls the electromagnetic directional control valve 100 to increase or decrease the hydraulic pressure in the control hydraulic chamber 90 to adjust the urging force of the spring 96 to a magnitude commensurate with the rear wheel load.

Further, the present invention can be applied not only to the front and rear two-system type hydraulic brake device, but also to a cross piping type hydraulic brake device and the like.

In addition, although not exemplified, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a system diagram of a hydraulic brake device according to an embodiment of the present invention. FIG. 2 is a graph showing the relationship between the master cylinder hydraulic pressure and the rear brake cylinder hydraulic pressure controlled by the hydraulic brake device. FIG. 3 is a system diagram of a hydraulic brake device according to another embodiment of the present invention. FIG. 4 is a system diagram of a conventional hydraulic brake device. 12: master cylinder, 26: left rear wheel 28: right rear wheel 30, 32: rear wheel cylinder 36: proportioning valve 38: anti-skid device 42: valve body, 54: valve piston 64: open / close valve, 70: first Hydraulic chamber 76: Second hydraulic chamber, 78: End face 80: End face, 84: Control piston 90: Control hydraulic chamber, 96: Spring 100: Electromagnetic directional control valve, 102: Reservoir 104: Accumulator, 106: Pump 110 : Rotation sensor 112: Control circuit 120: Proportioning valve 122: On-off valve, 124: Valve piston 126: Valve body 146: First pressure receiving surface 148: First hydraulic chamber, 154: End surface 156: Second hydraulic chamber

Claims (1)

[Scope of utility model registration request] 1. A brake for a rear wheel, which is slidably disposed in a valve body, receives a hydraulic pressure of a hydraulic pressure source on a first pressure receiving surface, and has a second pressure receiving surface having a larger area than the first pressure receiving surface. A valve piston that receives the hydraulic pressure of the cylinder, an opening / closing valve that allows and blocks the flow of brake fluid from the hydraulic pressure source to the brake cylinder based on the movement of the valve piston, and a hydraulic pressure source side from the opening / closing valve. Is provided on the first pressure receiving surface to apply the hydraulic pressure of the hydraulic pressure source to the first pressure receiving surface, and the second pressure receiving surface is provided on the rear wheel side with respect to the brake cylinder fluid on the second pressure receiving surface. It has a second hydraulic chamber for exerting a pressure and an urging means for urging the valve piston in the direction in which the on-off valve opens, and reduces the brake fluid supplied from the hydraulic pressure source at a constant ratio. Proportional to the brake cylinder And a control piston that is slidably disposed in the cylinder and that operates by receiving the hydraulic pressure of the control hydraulic chamber and that applies a control force to the valve piston in the direction opposite to the biasing force of the biasing means. Detecting the slip condition of the rear wheel, increasing the hydraulic pressure of the control hydraulic chamber to close the on-off valve and increase the volume of the second hydraulic chamber when the slip is excessive, A hydraulic brake device comprising an anti-skid device having a hydraulic pressure control device for reducing the hydraulic pressure of a brake cylinder of a rear wheel, wherein the valve piston and the control piston are separate bodies, and the urging means is provided. The biasing force is applied to the valve piston by abutting the control piston in a direction of abutting the valve piston, and,
A hydraulic brake device, wherein the control hydraulic chamber applies a hydraulic pressure to the control piston in a direction away from the valve piston.