JPH05467Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application The present invention relates to a hydraulic brake system for vehicles, and in particular, to improving the operating characteristics of a hydraulic brake system equipped with a volume-increasing anti-skid device. be.

BACKGROUND ART In a hydraulic brake system for a vehicle, a master cylinder that generates hydraulic pressure in response to the operation of an operating member such as a brake pedal, and a wheel cylinder that suppresses rotation of a wheel are connected by a main fluid passage. It is normal to Anti-skid devices are widely used in order to keep the slip rate of the wheels within an appropriate range and to safely and efficiently decelerate or stop the vehicle. One type of anti-skid device is called a volume increasing/reducing type or a closed type. In this system, a cut valve is provided in the middle of the main fluid passage that connects the master cylinder and the wheel cylinder to shut off the main fluid passage, and a hydraulic control piston is installed in the hydraulic control housing provided on the wheel cylinder side of the cut valve. are slidably fitted to form a first hydraulic pressure chamber that communicates with the wheel cylinder cut valve and a second hydraulic chamber that is isolated from the first hydraulic pressure chamber. As the hydraulic pressure in the pressure chamber is increased or decreased by the control of the electromagnetic hydraulic control valve, the hydraulic control piston moves forward to reduce the volume of the first hydraulic pressure chamber, opens the cut valve, and retreats. After closing the cut valve, the volume of the first hydraulic chamber is increased. Note that the electromagnetic hydraulic pressure control valve is controlled by a control device that is mainly a computer and has a function of detecting the slip rate of the wheels.

In a hydraulic brake system equipped with such a volume increase/decrease anti-skid device, once the hydraulic control piston retreats and the cut valve is closed, the hydraulic pressure control piston moves forward and backward to close the first hydraulic pressure chamber. Normally, the wheel cylinder hydraulic pressure is controlled within an appropriate range by increasing or decreasing the volume of the first hydraulic pressure chamber, or the wheel cylinder hydraulic pressure does not reach a sufficient level only by decreasing the volume of the first hydraulic pressure chamber. In this case, the cut valve is opened and high pressure brake fluid is supplied from the master cylinder side. However,
Even after the cut valve is closed and the increase in wheel cylinder fluid pressure is limited, the master cylinder's fluid pressure is normally allowed to rise further, so if the cut valve is once closed and then opened, high-pressure brake fluid The fluid suddenly flows into the wheel cylinder side, raising the wheel cylinder fluid pressure to an excessive value, causing a sudden increase in braking force, worsening the brake feeling, or causing the wheels to momentarily lock up. .

Japanese Utility Model Publication No. 50-43666 discloses means for avoiding the occurrence of such inconvenience.
This uses a first and second cut valve, and the first cut valve is always open while the second cut valve is closed, so that the brake fluid flowing from the master cylinder to the wheel cylinder has sufficient flow through the open first cut valve. However, once the first cut valve is closed and a pressure difference is created between the master cylinder side and the wheel cylinder side, the first cut valve remains closed and the second cut valve is opened. The brake fluid flowing from the master cylinder side to the wheel cylinder side is configured to flow through this second cut valve and a throttle passage provided in series therewith. In this way, if the brake fluid level on the wheel cylinder side is insufficient after the cut valve is closed and the brake fluid is replenished from the master cylinder side,
Since the sudden inflow of high-pressure brake fluid is prevented, the above-mentioned inconvenience can be avoided.

Problems to be Solved by the Invention However, in the device described in Japanese Utility Model Publication No. 50-43666, once the cut valve is closed, the brake fluid supplied from the master cylinder side to the wheel cylinder side is always throttled. Therefore, even if the fluid pressure difference between the master cylinder and the wheel cylinder is relatively small, the brake fluid will be subject to the throttling effect and will not be able to flow in at a sufficient speed, resulting in a longer braking distance for the vehicle. There was a problem that there were cases.

Means for Solving the Problem In order to solve this problem, the present invention allows a large flow of brake fluid to flow into the main fluid passage in a hydraulic brake system equipped with a volume increasing/reducing anti-skid device as described above. A throttle valve is provided that can be in an inactive state to throttle the flow of brake fluid and an active state to throttle the flow of brake fluid, and the throttle valve is always kept in an inactive state to reduce the difference between the hydraulic pressure in the master cylinder and the hydraulic pressure in the wheel cylinder. A throttle valve control device is provided which puts the throttle valve into operation when the cut valve is opened in a state in which is above a certain value.

In a preferred embodiment of the present invention, the throttle valve control device includes (a) a valve housing having a liquid passage forming a part of the main liquid passage; and (b) movably provided within the valve housing; A valve control piston that cooperates with the housing to form a master cylinder side chamber connected to the master cylinder and a wheel cylinder side chamber connected to the wheel cylinder, and has a communication passage that communicates the master cylinder side chamber and the wheel cylinder side chamber. and,
(c) a spring that biases the valve control piston toward the master cylinder side chamber;
() A valve hole formed in the valve housing,
() When the valve control piston is in the master cylinder side chamber, it is away from the valve hole and is in an inactive state that allows a large flow of brake fluid. It includes a valve element that is in a working state to restrict the flow of brake fluid in cooperation with the valve hole when moved to the side, and the communication passage is normally located between the master cylinder side chamber and the wheel cylinder side chamber of the spring. Although a sufficient hydraulic pressure difference is not generated to move the valve piston toward the wheel cylinder side chamber against the biasing force, the cut valve communicates between the master cylinder and the wheel cylinder in a state where the hydraulic pressure difference between the master cylinder and the wheel cylinder exceeds the predetermined value. When the valve control piston is moved toward the wheel cylinder side chamber, it has a throttling effect that creates a hydraulic pressure difference between the master cylinder side chamber and the wheel cylinder side chamber that is sufficient to overcome the biasing force of the spring and move the valve control piston toward the wheel cylinder side chamber. It is considered to be a mechanical control valve.

In another aspect, the throttle valve is an electromagnetic switching type throttle valve that can be switched between a non-operating state that allows a large flow of brake fluid to flow and an active state that throttles the flow of brake fluid. The control device is (a)
A differential pressure detector detects the difference in fluid pressure between the master cylinder and the wheel cylinder, and (b) the differential pressure detector is connected to the electromagnetic switching throttle valve, and the electromagnetic switching throttle valve is always kept inactive. , the electromagnetic control type includes a switching device that switches the electromagnetic switching type throttle valve to the operating state when the hydraulic pressure difference is above the predetermined value.

Functions and Effects In the hydraulic brake system with a volume increasing/reducing anti-skid device according to the present invention, when the once-closed cut valve is reopened, if the difference between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure is above a certain value, then Since the throttle valve control device puts the throttle valve in a state that throttles the flow of brake fluid, the inflow speed of brake fluid flowing from the master cylinder side to the wheel cylinder side is limited to an appropriate value, and the wheel cylinder fluid pressure suddenly becomes excessive. As a result, deterioration of brake feeling and temporary wheel locking are prevented.

Moreover, the throttle valve control device keeps the throttle valve in a state that allows a large amount of brake fluid to flow when the difference between the master cylinder hydraulic pressure and the wheel cylinder hydraulic pressure does not exceed a certain value, so the cut valve is closed. Even if the master cylinder fluid pressure has not increased that much after the cut valve is opened, brake fluid is replenished to the wheel cylinder side at a sufficient speed, increasing the braking distance due to a temporary lack of wheel cylinder fluid pressure. is avoided.

In addition, especially when the throttle valve control device is a mechanical type, an electric control device is not required, which reduces the device cost. Switching between the state of restricting the flow and the state of not restricting the flow becomes accurate, and it becomes easy to perform fine control.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In Fig. 1, 10 is a brake pedal;
Master cylinder 1 via brake booster 12
Connected to 4. The master cylinder 14 is a tandem type having two pressurizing chambers, one pressurizing chamber is connected to the actuator 18 via a liquid passage 16 and a control valve 17, and each of the pressurizing chambers is connected to an actuator 18 through a liquid passage 16 and a control valve 17.
0 and 22 to the wheel cylinder 26 of the left front wheel 24 and the wheel cylinder 30 of the right rear wheel 28. The other pressurized chamber is the liquid passage 32
and the actuator 18 via the control valve 33, and further connected to the wheel cylinder 40 of the right front wheel 38 and the wheel cylinder 44 of the left rear wheel 42 by liquid passages 34 and 36, respectively. Liquid passages 16, 20, 22, 32, 34, 36
etc. are master cylinder 14 and wheel cylinder 2.
6, 30, 40, and 44, forming a main liquid passageway that connects them, forming a so-called diagonal piping. Although not shown, the liquid passage 22
and 36 is preferably provided with a poro positioning valve.

The actuator 18 includes cut valves 50, 52, 54 and 56 corresponding to the wheel cylinders 26, 40, 30 and 44, respectively, and bypass valves 58, 60, 62 and 64. The cut valve 50 includes a ball-shaped valve element 70 that is urged by a spring 66 in the direction of seating on the valve seat 68.
A hydraulically controlled piston 72 is provided to push it away. The hydraulic control piston 72 is fluid-tightly and slidably fitted into the hydraulic control housing 73. This hydraulic pressure control piston 72 is actuated by a hydraulic pressure difference between a first hydraulic pressure chamber 74 and a second hydraulic pressure chamber 76 on both sides thereof, and allows the valve element 70 to sit on the valve seat 68 when retracting. The volume of the first hydraulic pressure chamber 74 is increased during forward movement, and after the volume of the first hydraulic pressure chamber 74 is decreased during forward movement, the valve element 70 is pushed away from the valve seat 68. The first hydraulic chamber 74 is connected to the liquid passage 20 by a liquid passage 78 . Moreover, the bypass valve 58 is
A ball-shaped valve element 84 is urged by the spring 66 in a direction away from the valve seat 80 and closer to the valve seat 82, and the valve element 84 is pushed toward the valve seat 80.
A piston 86 is provided. The piston 86 keeps the valve element 84 seated on the valve seat 80 as long as hydraulic pressure is applied to the hydraulic chamber 88.
While the first hydraulic pressure chamber 74 continues to communicate with the wheel cylinder 26, when the hydraulic pressure no longer acts on the hydraulic pressure chamber 88, the valve element 84 separates from the valve seat 80 and the brake from the master cylinder 14 is removed. The fluid bypasses the cut valve 50 and enters the wheel cylinder 26.
Allow it to flow to the side. Although the cut valve 50 and the bypass valve 58 have been described above, the other cut valves 52, 54 and 56 and the bypass valves 60, 62 and 64 have similar structures.

The hydraulic pressure chamber 88 is directly connected to the control valve 102 by a liquid passage 100, while the second hydraulic pressure chamber 76 is connected to the electromagnetic hydraulic pressure control valve 104 and the liquid passage 106.
and is connected to a control valve 102 via a liquid passage 100. Further, the cut valve 52 corresponding to the wheel cylinder 40 of the right front wheel 38 is also independently connected to the control valve 102 via the electromagnetic hydraulic pressure control valve 108, but the cut valve 52 corresponding to the wheel cylinder 40 of the left and right rear wheels 28 and 42 is also connected to the control valve 102 independently. cut valve 54
and 56 are connected to the control valve 102 via a common electromagnetic hydraulic pressure control valve 110.

Each electromagnetic hydraulic pressure control valve 104, 108, 110 is
Hydraulic fluid supplied from each control valve 102 is supplied to the second hydraulic pressure chamber 76 etc. of each cut valve 50, and hydraulic fluid is supplied from the second hydraulic pressure chamber 76 etc. to the liquid passage 112.
The hydraulic pressure in the second hydraulic pressure chamber 76 and the like is controlled by allowing the hydraulic pressure to flow into the reservoir 114 through the hydraulic pressure chamber 114, but since it is well known, a detailed explanation will be omitted.

The control valve 102 is pumped from the reservoir 114 by a pump 120,
The hydraulic pressure of the hydraulic fluid stored in the hydraulic fluid 22 is controlled to be slightly higher than the hydraulic pressure of the master cylinder 14 and supplied to the electromagnetic hydraulic pressure control valve 104 and the like. 16 and is also connected to the reservoir 114 by a liquid passage 126 and the liquid passage 112.

The control valve 102 includes a valve seat member 132, a cylinder 134, and a plug 136 disposed within the housing 130 of the actuator 18, as shown in FIG.
In the cavity formed inside these, a ball-shaped valve element 138, a valve member 140 with a ball-shaped valve part, a piston 142 with a through hole in the center, and the piston 142 is made liquid-tight. and a piston 146 that slidably receives one end of the rod 144 in the axial direction.
etc., the liquid chamber 1 has four empty spaces.
It is divided into 48, 150, 152 and 154. The liquid chamber 148 is connected to the accumulator 12.
2, the liquid chamber 150 is connected to the bypass valve 58, the electromagnetic control valve 104, etc., and the liquid chamber 152 is connected to the reservoir 11.
4, the liquid chambers 154 are each connected to the master cylinder 14.

Valve element 138, valve member 140, piston 142,
Rod 144 and piston 146 are normally maintained in the position shown in FIG. 2 by springs 156, 158, 160 and 162, respectively.
The valve element 138 is seated on the valve seat member 132 to open the liquid chamber 14.
At the same time, the valve portion of the valve member 140 closes a communication passage 164 formed in the rod 144, thereby cutting off communication between the liquid chambers 150 and 152. When hydraulic pressure is applied to the liquid chamber 154 from the master cylinder 14, the piston 146 moves forward to move the valve member 140 and valve element 138 to the left in FIG. The chambers 148 and 150 are brought into communication.
As a result, high pressure hydraulic fluid flows from the fluid chamber 148 into the fluid chamber 1.
50, the hydraulic pressure in the liquid chamber 150 increases, and the piston 142 is moved (backward) to the right against the urging force of the spring 160, causing the rod 144 and the piston 146 to move backward. As a result, the valve element 138 is seated on the valve seat member 132 and the liquid chamber 148
and 150 are cut off. When the piston 142 moves further to the right, the valve member 140 comes into contact with the stopper 170 and stops, and the rod 144 separates from the valve member 140 and the liquid chamber 150 opens into the communication passage 164.
The liquid chamber 150 is communicated with the liquid chamber 152 by
The hydraulic fluid flows out toward the reservoir 114, and the hydraulic pressure in the fluid chamber 150 decreases.

By repeating the above operation, the fluid pressure of the master cylinder 14 acting on the fluid chamber 154 causes the fluid chamber 15 to
In this embodiment, the outer diameters of the pistons 142 and 146 are made equal, and the piston 142 is connected to the rod 14.
4 away from the valve member 140 and the liquid chambers 150 and 1
Because it is necessary to move against the biasing force of the spring 160 in order to communicate with the fluid chamber 152, the fluid pressure in the fluid chamber 150 is maintained at a slightly higher value than the fluid pressure in the fluid chamber 154. Become. That is, the hydraulic pressure of the hydraulic fluid supplied from the liquid chamber 150 to the bypass valve 58, the electromagnetic hydraulic pressure control valve 104, etc.
Therefore, the hydraulic pressure of the master cylinder 14 applied to the master cylinder 14 is controlled to be slightly higher than the hydraulic pressure applied to the master cylinder 14. In addition, 1
66 is a spring retainer, and 168 is a stop ring that defines the forward limit of the piston 142.

As is clear from FIG. 1, the electromagnetic hydraulic pressure control valves 104, 108 and 110 are
controlled by. The control device 180 is mainly composed of a computer, and controls each of the wheels 24,
Sensors (rotational speed detectors) 182, 184 provided corresponding to 28, 38 and 42, respectively.
The slip rate of each wheel is calculated based on the output signals of the wheels 186 and 188, and the electromagnetic hydraulic pressure control valve 104 and the like are controlled so that the slip rate falls within an appropriate range.This control is well known. Therefore, detailed explanation will be omitted. The control device 180 also controls a hydraulic switch 19 provided on the accumulator 122.
It also functions to start and stop the transmission motor 192 that drives the pump 120 based on the zero output signal, and to ensure that the hydraulic fluid within a constant hydraulic pressure range is always stored in the accumulator 122. Control device 18
0 functions as a main control device for controlling the actuator 18, and together with the actuator 18 constitutes a volume increase/decrease type anti-skid device.

The control valves 17 and 33 are identical.
The control valve 17 is provided with a valve housing 200 having a liquid passage therein which forms a part of the main liquid passage. A valve control piston 202 is fitted in the valve housing 200 in a substantially liquid-tight and slidable manner to form a master cylinder side chamber 204 and a wheel cylinder side chamber 206. A valve element 208 is integrally provided with the valve control piston 202, while a valve element 208 is formed in the valve housing 200.
0 is formed with a valve hole 210, and these
12. Valve control piston 202
Also formed in the master cylinder 14 is a communication passage 214 that communicates the master cylinder side chamber 204 and the wheel cylinder side chamber 206, and the brake fluid that flows from the master cylinder 14 into the master cylinder side chamber 204 reaches the wheel cylinder side chamber 206 through this communication passage 214, and flows out to the actuator 18 side through the throttle valve 212. The valve control piston 202 is biased toward the master cylinder side chamber 204 by a spring 216, and is always in the first position, causing the valve element 208 to separate from the valve hole 210 and maintaining the throttle valve 212 in a state in which it does not perform a throttling action. However, since the communication passage 214 has a certain degree of throttling function, the fluid passage 1 is configured to have a certain degree of throttling function.
When the flow velocity of the brake fluid flowing through valve 6 becomes extremely large, valve control piston 202 moves toward wheel cylinder side chamber 206 against the biasing force of spring 216, causing valve element 208 to fit into valve hole 210 and causing throttle valve 212 to be throttled.

As is clear from the above description, in this embodiment, the valve housing 200, the valve control piston 202, and the spring 216
08 and a valve element 210 constitutes a throttle valve control device that controls a throttle valve 212.

Next, the operation of the left front wheel 24 system will be explained as a representative example.

When hydraulic pressure is generated in the master cylinder 14 in response to depression of the brake pedal 10, the hydraulic pressure is supplied to the control valve 102 via the liquid passage 16, the control valve 17, and the liquid passage 124, and as a result, the control valve 10
2 reduces the hydraulic pressure of the accumulator 122 to a hydraulic pressure slightly higher than the hydraulic pressure of the master cylinder 14 and supplies it to the liquid passage 100. This hydraulic pressure acts on the hydraulic chamber 88 to close the bypass valve 58, and also acts on the second hydraulic chamber 76 via the hydraulic passage 106 and the electromagnetic hydraulic pressure control valve 104, causing the hydraulic control piston 72 to move forward. to open the cut valve 50. Therefore, the hydraulic pressure in the master cylinder 14 is transmitted from the cut valve 50 to the wheel cylinder 26 via the hydraulic passages 78 and 20. At this time, the brake fluid passes through the communication passage 214 of the control valve 17, but at that flow rate, the valve control piston 202
There is no hydraulic pressure difference before and after which causes the valve control piston 202 to operate against the biasing force of the spring 216, and the throttle valve 212 is kept in a non-throttled state.

When hydraulic pressure is transmitted to the wheel cylinder 26 and braking force is applied to the left front wheel 24 so that its slip ratio exceeds the appropriate range, the control device 180 detects this fact based on the output signal of the sensor 182, and transmits the electromagnetic fluid. The pressure control valve 104 starts anti-skid control operation, and the hydraulic pressure in the wheel cylinder 26 is controlled as shown in FIG. That is, first, the second hydraulic pressure chamber 76 is cut off from the control valve 102, while being communicated with the reservoir 114 to lower its hydraulic pressure. When the hydraulic pressure in the second hydraulic chamber 76 decreases, the hydraulic control piston 72 retreats, closing the cut valve 50 and increasing the volume of the first hydraulic chamber 74. Thereby the wheel cylinder 26
When the hydraulic pressure of the left front wheel 24 decreases and the slip rate of the left front wheel 24 decreases, the control device 180 controls the electromagnetic hydraulic pressure control valve 104.
The hydraulic pressure in the second hydraulic pressure chamber 76 is kept constant or increased by switching to a holding state or a pressure increase allowing state. If the hydraulic pressure in the second hydraulic chamber 76 is increased, the hydraulic control piston 72 moves forward and the first hydraulic chamber 76 moves forward.
4 is decreased, and the hydraulic pressure of the wheel cylinder 26 is increased. By this alone, if the hydraulic pressure in the wheel cylinder 26 rises to a sufficient level, the cut valve 50 will not open, but if the hydraulic pressure in the wheel cylinder 26 is insufficient, the hydraulic control piston 72 will open. The cut valve 50 is opened to allow the brake fluid in the fluid passage 16 on the master cylinder 14 side to flow into the fluid passage 20 on the wheel cylinder 26 side.

At this time, if the differential pressure between the hydraulic pressure in the master cylinder 14 and the hydraulic pressure in the wheel cylinder 26 is not so large, that is, if the hydraulic pressure in the wheel cylinder 26 has not been increased that much since the cut valve 50 was closed, Since the speed of the brake fluid flowing through the fluid passage 16 is relatively low, the communication passage 214
The hydraulic pressure difference created between the master cylinder side chamber 204 and the wheel cylinder side chamber 206 due to the throttling action does not move the valve control piston 202 forward against the biasing force of the spring 216. Therefore, the throttle valve 212 does not restrict the flow of brake fluid, and the flow of the brake fluid is not restricted to the master cylinder 14.
Although the hydraulic pressure difference between the brake fluid and the wheel cylinder 26 is relatively low, brake fluid is replenished to the wheel cylinder 26 at a sufficient speed, and the wheel cylinder 2
The hydraulic pressure of No. 6 is quickly raised.

On the other hand, if the difference in hydraulic pressure between the master cylinder 14 and the wheel cylinder 26 is large when the cut valve 50 opens, the speed of the brake fluid flowing through the liquid passage 16 increases significantly, so that the communication passage 214 is throttled. Master cylinder side chamber 2
04 and the wheel cylinder side chamber 206 increases, causing the valve control piston 202 to move to the second position against the biasing force of the spring 216. As a result, the throttle valve 212
This restricts the flow of brake fluid, so the brake fluid in the fluid passage 16 on the master cylinder 14 side flows into the fluid passage 20 on the wheel cylinder 26 side at an excessive speed.
This prevents water from flowing into the environment. That is, in a state where the hydraulic pressure difference between the master cylinder 14 and the wheel cylinder 26 exceeds a certain value, the cut valve 50
When the wheel is opened, conventionally, the hydraulic pressure in the wheel cylinder 26 is suddenly increased as shown by the two-dot chain line in FIG. 3, and the wheel becomes temporarily locked.
While there have been cases where the brake feeling deteriorates, the device of this embodiment avoids such inconveniences. Moreover, since the control valve 17 operates when it senses that the hydraulic pressure difference between the master cylinder 14 and the wheel cylinder 26 is above a certain value, and throttles the flow of brake fluid, an electric control device is required. It is not necessary to provide a , and it can be manufactured at low cost.

As is clear from the above explanation, in this embodiment, the mechanically operated control valve 17 functions as a throttle valve and a throttle control device, but an electromagnetic switching type throttle valve is used instead. It is also possible to do so. An example is shown in FIG. However, only the system of the left front wheel 24 is shown, and the rest will be omitted because they are the same as the embodiment shown in FIG.

The electromagnetic switching type throttle valve 230 is an electromagnetic valve that can switch the flow of brake fluid in the fluid passage 16 between a non-throttling state and a throttling state, and is controlled by a control device 232. The control device 232 has the same function as the control device 180 in the embodiment described above, and also has the function of a throttle valve control device for controlling the electromagnetic switching type throttle valve 230.
A hydraulic pressure sensor 234 that detects the hydraulic pressure of the liquid passage 20
A hydraulic pressure sensor 236 that detects hydraulic pressure is connected to the control device 232. The control device 232 keeps the electromagnetic switching throttle valve 230 in the non-throttling state when the difference between the output signals of the hydraulic pressure sensors 234 and 236 is smaller than a certain value, and switches it to the throttling state when the difference is above the certain value. It's becoming like that. The hydraulic pressure sensors 234 and 236 constitute a differential pressure detector.

Therefore, when the cut valve 50 of the actuator 18 is opened when the hydraulic pressure difference between the master cylinder 14 and the wheel cylinder 26 is above a certain value, the electromagnetic switching throttle valve 230 is in the throttled state, and the master cylinder 14 Side liquid passage 16
The brake fluid flows into the fluid passage 20 on the wheel cylinder 26 side at an excessive speed, causing the wheel cylinder 2
6 is avoided, while the master cylinder 14 and the wheel cylinder 26
If the hydraulic pressure difference between the master cylinder 14 and the wheel cylinder 26 is smaller than a certain value, the electromagnetic switching throttle valve 230 is kept in a non-throttling state and the hydraulic pressure in the wheel cylinder 26 is maintained even though the hydraulic pressure difference between the master cylinder 14 and the wheel cylinder 26 is small. will be raised at a sufficient speed.

Note that the electromagnetic switching type throttle valve is not limited to the one described above, and it is also possible to employ a combination of a fixed throttle 240 and an electromagnetic shut-off valve 242 as shown in FIG.

Above, two or three embodiments of the present invention have been described in detail based on the drawings, but the present invention should not be construed as being limited to these. 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 the drawing]

FIG. 1 is a system diagram showing a hydraulic brake device with a volume increasing/decreasing anti-skid device, which is an embodiment of the present invention. 2 is a front sectional view showing the structure of the control valve in FIG. 1. FIG. FIG. 3 is a graph conceptually showing the hydraulic pressure control status of the wheel cylinder in the hydraulic brake device. FIG. 4 is a system diagram showing a part of a hydraulic brake device with an anti-skid device of a volume increasing/decreasing type according to another embodiment of the present invention. FIG. 5 is a diagram showing a solenoid valve used in another embodiment of the present invention. 14... Master cylinder, 17... Control valve, 1
8... Actuator, 26, 30... Wheel cylinder, 33... Control valve, 40, 44... Wheel cylinder, 50, 52, 54, 56... Cut valve, 58, 60, 62, 64... Bypass valve, 72... Hydraulic pressure control piston, 74... First hydraulic chamber, 76... Second hydraulic chamber, 102... Control valve, 104, 108, 110... Electromagnetic hydraulic pressure control valve, 180... Control device , 200...Housing, 200...Valve housing, 202...Valve control piston, 204...Master cylinder side chamber, 206...Wheel cylinder side chamber, 208...
... Valve, 210 ... Valve hole, 212 ... Throttle valve, 2
14...Communication path, 216...Spring, 230
...Electromagnetic switching throttle valve, 232...Control device, 2
34,236...Liquid pressure sensor, 240...Aperture,
242...Solenoid on-off valve.

Claims (1)

[Claims for Utility Model Registration] (1) A cut valve is provided in the middle of the main fluid passage connecting the master cylinder and the wheel cylinder to shut off the main fluid passage, and a cut valve is provided on the side of the wheel cylinder from the cut valve. A first hydraulic pressure chamber communicates with the wheel cylinder and the cut valve by slidably fitting a hydraulic control piston into the hydraulic control housing, and a second hydraulic chamber that is isolated from the first hydraulic pressure chamber. is formed, and the hydraulic pressure in the second hydraulic pressure chamber is increased or decreased by the control of the electromagnetic hydraulic pressure control valve, whereby the hydraulic pressure control piston moves forward to increase the volume of the first hydraulic pressure chamber. After decreasing the pressure, the cut valve is opened, and after moving backward and closing the cut valve, the volume of the first hydraulic chamber is increased, so that the slip ratio of the wheel provided with the wheel cylinder is within an appropriate range. In a hydraulic brake system with a volume increase/decrease anti-skid control device in which the hydraulic pressure of a wheel cylinder is controlled, the main fluid passage has two states: a non-operating state that allows a large flow of brake fluid to flow into the main fluid passage, and an active state that throttles the flow of brake fluid. and the cut valve is provided with a throttle valve capable of controlling the flow rate, and the throttle valve is always kept in the inactive state, and the cut valve is operated when the difference between the hydraulic pressure of the master cylinder and the hydraulic pressure of the wheel cylinder is a certain value or more A hydraulic brake device characterized in that the hydraulic brake device is provided in a throttle valve control device that brings the throttle valve into the operating state when the throttle valve is opened. (2) The throttle valve control device includes a valve housing including a liquid passage forming a part of the main liquid passage, and is movably provided within the valve housing and connected to the master cylinder together with the valve housing. a valve control piston that forms a master cylinder side chamber connected to the wheel cylinder and a wheel cylinder side chamber connected to the wheel cylinder, and is provided with a communication passage that communicates the master cylinder side chamber and the wheel cylinder side chamber; a spring that biases the throttle valve toward the master cylinder side chamber side, and the throttle valve is connected to a valve hole formed in the valve housing, and when the valve control piston is on the master cylinder side chamber side, the valve control piston is separated from the valve hole and brakes. When the valve control piston is in a non-operating state that allows a large flow of fluid to flow, and the valve control piston moves toward the wheel cylinder side chamber against the biasing force of the spring, the brake fluid flows together with the valve hole. and a valve element that is in a state of action to throttle the valve, and the communication passage is always between the master cylinder side chamber and the wheel cylinder side chamber so as to move the valve piston toward the wheel cylinder side chamber against the biasing force of the spring. However, when the cut valve connects the master cylinder and wheel cylinder with the hydraulic pressure difference exceeding the certain value, the master cylinder side chamber and the wheel cylinder side chamber Claim 1, which has a throttling effect that creates a hydraulic pressure difference sufficient to move the valve control piston toward the wheel cylinder side chamber against the biasing force of the spring. Hydraulic brake device. (3) The throttle valve is an electromagnetic switching throttle valve that can be switched between a non-operating state that allows a large flow of brake fluid to flow and an active state that throttles the flow of brake fluid, and the throttle valve control device is , a differential pressure detector that detects a difference in fluid pressure between the master cylinder and the wheel cylinder; and a differential pressure detector that is connected to the electromagnetic switching throttle valve, and which normally keeps the electromagnetic switching throttle valve in the non-operating state. and a switching device for switching the electromagnetic switching type throttle valve to the operating state when the fluid pressure difference is equal to or higher than the certain value.
Hydraulic brake device as described in section.