JPH04107369A - Spool type electromagnetic hydraulic pressure control device - Google Patents

Abstract

PURPOSE:To prevent hydraulic lock of a spool by providing an on-off valve control means to connect an on-off valve to a high pressure port, open the on-off valve when the control force of a control force exerting means is exerted and close it when the control force is not exerted. CONSTITUTION:In prior to move a spool 58 through the feed of a current to a coil 100, a solenoid on-off valve 120 is opened and after the spool 58 is returned to an original position, the electromagnetic on-off valve 120 is closed. During inoperation of an electromagnetic hydraulic pressure control valve 24, a high pressure port 72 is disconnected from an accumulator 26, and the hydraulic pressure of an annular groove 82 is reduced owing to leakage through a gap between the spool 58 and a valve hole 52. Thus, even when the inoperative state of the electromagnetic hydraulic pressure control valve 24 is continued, the unbalance of hydraulic pressure is produced at the periphery of the spool 58, hydraulic lock is prevented from occurring, and a delay in the rise of a control hydraulic pressure is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a spool-type electromagnetic hydraulic control device, and particularly to a technique for preventing hydraulic locking of the spool.

A conventional spool-type electromagnetic hydraulic pressure control valve controls hydraulic pressure by switching the flow of liquid by moving a spool. As a type of this hydraulic pressure control valve, for example,
There is one described in Publication No. 3. This control valve is (a
) a housing having a high pressure port, a low pressure port, and a control pressure port; (C) a spool that selectively communicates with the low pressure port; (C) biasing means that biases the spool to a position that blocks the control pressure port from the high pressure port; (d)
(e) an actuating force generating means for generating an actuating force to actuate the spool in a direction to isolate the control pressure port from the high pressure port by applying a force based on the hydraulic pressure of the control pressure port to the spool; and (e) an excitation coil. and control force applying means for applying a control force to the spool in a direction opposite to the operating force of the operating force generating means by controlling the current supplied to the exciting coil. Normally, the spool is kept in a position that blocks the control pressure port from the high pressure port by the biasing means, but if an exciting current is supplied and a control force is applied to the spool by the control force applying means, the spool will move. to connect the control pressure port to the high pressure port,
Hydraulic pressure control is performed.

Problems to be Solved by the Invention In the spool-type electromagnetic hydraulic control valve described above, if the state in which no control force is applied, that is, the state in which the spool is in the original position where the control pressure port 1- is partially cut off from the high-pressure port, the spool The hydraulic fluid that is eccentric within the valve hole and slightly leaks from the high pressure port side to the low pressure port side flows through the large gap between the spool and the valve hole. Since the hydraulic pressure within the gap tends to be higher in areas where the gap is larger, an imbalance of hydraulic pressure occurs around the spool, and the spool is eventually pressed against a part of the inner peripheral surface of the valve hole. A large frictional force is generated, resulting in a so-called hydraulic lock. If hydroliter lock occurs, the next time a control force is applied to the spool, the spool will not move easily, causing a delay in communication between the control pressure port and the high pressure port, resulting in a delay in the rise of control fluid pressure. occurs.

As an example, FIG. 4 shows a graph of the measured current and corresponding hydraulic pressure when the excitation current is linearly increased and then linearly decreased. As is clear from the upper graph, when the excitation current is continuously increased and decreased to continuously operate the control valve, the hydraulic pressure quickly increases in response to the increase in the current. On the other hand, as shown in the lower graph, when the control valve is left inactive for 10 minutes and then current is supplied, it takes about 2 seconds for the hydraulic pressure to rise compared to when it is continuously operated. There are delays. This is believed to be due to hydraulic lock occurring while the spool was in its original position for 10 minutes. Therefore, in the above control valve, when we measured the occurrence of hydro-litter lock by changing the hydraulic pressure acting on the high pressure port, that is, the hydraulic pressure of the hydraulic pressure source communicating with the high pressure port, we found that the hydraulic pressure of the hydraulic pressure source was
It was found that when the value was set to a low value of 0 kg/crR or less, hydroliter lock did not occur.

In view of the above-mentioned problems and the above-mentioned measurement results, the present invention has been made with the object of preventing the hydraulic lock of the spool.

Means to solve problems The gist of the present invention is the above-mentioned (a) housing.

In a spool-type electromagnetic hydraulic control device having (b) a spool, (C) a biasing means, (d) an operating force generating means, and (e) a control force applying means, an on-off valve is connected to a high pressure port, and a control force is provided. The present invention is provided with an on-off valve control means that opens the on-off valve when the control force is applied to the application means and closes the on-off valve when the control force is not applied.

Function In the electromagnetic hydraulic pressure control device configured as described above, the on-off valve is always closed, so when no control force is applied, that is, when the spool is in its original position, a slight leak will cause the hydraulic pressure in the high pressure port to drop. becomes low, and high hydraulic pressure is prevented from acting on the spool. In other words, by closing the on-off valve when the control valve is not in operation, it is possible to prevent the spool from becoming hydrolitter-locked due to hydraulic imbalance under high pressure. On the other hand, when a braking force is applied and the spool moves, the on-off valve is opened to increase the hydraulic pressure in the high pressure port, and high hydraulic pressure is supplied to the control pressure port. Since the on-off valve is controlled by the on-off valve control means to be opened when the control valve is activated, there is no problem.

Effects of the Invention As described above, according to the present invention, delays in spool movement due to hydrolitter lock can be reliably avoided, and delays in the rise of control hydraulic pressure can be prevented.

In particular, if the on-off valve is connected in series to the electromagnetic hydraulic control valve as an electromagnetic on-off valve, and the excitation current required to open the electromagnetic on-off valve is made smaller than the operation start current of the electromagnetic hydraulic control valve, electromagnetic hydraulic pressure control can be achieved. Since the electromagnetic on-off valve is inevitably opened when the valve is activated, the reliability of the device can be improved, the structure of the device can be simplified, the device can be made smaller, and costs can be reduced. It will be done.

EXAMPLE Hereinafter, a case in which the present invention is applied to a spool-type electromagnetic hydraulic control device for a hydraulic brake device for an automobile will be explained in detail based on the drawings.

In FIG. 2, 10 and 12 are front wheel cylinders for the left and right front wheels, respectively, and 14 and 16 are rear wheel cylinders for the left and right rear wheels, respectively. These wheel cylinders 10, 12, 14, 16 have hydraulic pressure generated in the mask cylinder 22 based on the depression of the brake pedal 20 by switching the change valve 18, and electromagnetic hydraulic pressure generated based on the depression of the brake pedal 20. The hydraulic pressure of the accumulator 26 controlled by the control valve 24 is alternatively supplied. The depression force on the brake pedal 20 is detected by the depression force sensor 28 and is supplied to the controller 30. The controller 30 calculates an excitation current to the electromagnetic hydraulic pressure control valve 24 based on the depression force of the brake pedal 20 and the vehicle body acceleration supplied from the acceleration sensor 32, and supplies the exciting current to the electromagnetic hydraulic pressure control valve 24 via the operation amplifier 34. supplying the wheel cylinders 10, 12゜14.
．． 16 is controlled to a height corresponding to the depression force of the brake pedal 20. Brake fluid pumped up from a reservoir 36 by a pump 38 is always stored in the accumulator 26 within a constant hydraulic pressure range. 40 is a motor that drives the pump 34. In this hydraulic brake system, hydraulic pressure controlled by the electromagnetic hydraulic pressure control valve 24 is normally supplied to the wheel cylinders 10, 12, 14, 16, but if an abnormality occurs on the electromagnetic hydraulic pressure control valve 24 side. In this case, the hydraulic pressure generated in the mask cylinder 22 is supplied to ensure braking force. The control pressure of the electromagnetic hydraulic pressure control valve 24 (hydraulic pressure of the control pressure port 78) is made to be slightly higher than the hydraulic pressure of the mask cylinder 22.

In addition, in this hydraulic brake device, the controller 3
A travel control computer 42 is connected to the vehicle 0, and by operating a switch (not shown), hydraulic pressure control by the travel control computer 42 is performed in addition to hydraulic pressure control based on the pedal force from the pedal force sensor 28.

The electromagnetic hydraulic pressure control valve 24 includes a housing 50, as shown in FIG. The housing 50 is made up of a plurality of blocks fixed to each other, but is shown as an integral piece in the figure. Inside the housing 50, a bottomed valve hole 52 having a circular cross-sectional shape and a large stepped space 56 located on the open end side of the valve hole 52 communicate with each other and are formed concentrically. There is.

A spool 58 is fitted into the valve hole 52 in a substantially liquid-tight and slidable manner. The spool 58 has a stepped shape, and a small diameter part 64 is formed between a first large diameter part 60 and a second large diameter part 62, and a small diameter part 64 is formed in the valve hole 52 at the first and second large diameter parts 60°62. When fitted, the first large diameter portion 60 is sized to protrude from the valve hole 52 into the space 56 . The clearance between the outer circumferential surfaces of the first and second large diameter portions 60, 62 and the inner circumferential surface of the valve hole 52 is extremely small, 10 μm or less in diameter, and there is no metal between the outer circumferential surface and the inner circumferential surface. A seal is formed. Also formed in the housing 50 is a bottomed pin hole 66 that is concentric with the valve hole 52, opens at its bottom, and has a smaller diameter than the valve hole 52, into which a reaction pin 68 is slidably fitted. At the same time, the spring 70 projects into the valve hole 52 and is biased in a direction to come into contact with the spool 58 .

Housing 50 further includes a high pressure port 72 . connected to accumulator 26 . First and second low pressure ports 74, 76 connected to the reservoir 36 and control pressure ports 78 connected to the wheel cylinders 10-16 are formed. The control pressure port 78 is connected to the small diameter portion 64 of the spool 58.
The high pressure port 72 communicates with an annular groove 82 formed in the bottom side of the control pressure port 78 of the valve hole 52. I'm forced to. Further, the first low pressure port 74 is communicated with the bottom of the valve hole 52, and the second low pressure port 76 is communicated with an annular groove 84 formed on the opening side of the valve hole 52 from the control pressure port 78 of the valve hole 52. It is being Further, a liquid passage 86 branched from the control pressure port 78 is connected between the bottom surface of the pin hole 66 and the reaction force pin 68, and the reaction force pin 68 receives the liquid pressure of the control pressure port 78. Then, an operating force based on the hydraulic pressure is applied to the spool 58 to generate an operating force that cuts off communication between the high pressure port 72 and the control pressure port 78. In this embodiment, the reaction force pin 68 and the liquid passage 86 constitute actuation force generating means.

Ends of a diaphragm 90 are respectively engaged with the protrusion from the valve hole 52 of the first large diameter portion 60 of the spool 58 and the inner peripheral surface of the space 56, and the space 56 is connected to the drain port 9.
2 into a drain chamber 94 communicated with the reservoir 36 and an air chamber 96 filled with air. A force smoke 98 is provided in the air chamber 96. Brake fluid leaking from the metal-to-metal seal between the first large diameter portion 60 and the valve hole 62 flows into the drain chamber 94 , and this brake fluid returns to the reservoir 36 through the drain port 92 .

A small-diameter threaded portion 99 is protruded from the end of the spool 58 protruding from the valve hole 52, and the coil 100 of the force smoke 98 is attached to a holding member 102 made of a non-magnetic material fixed to the threaded portion 99. It is held and fitted into an annular groove 104 formed in the yoke 103. The yoke 103 includes a permanent magnet 106, and the holding member 102 is in the magnetic path of the permanent magnet 106. When no excitation current is supplied to the coil 100, the biasing force of the spring 70 maintains the spool 58 in its original position communicating the control pressure port 78 with the second low pressure port 76, as shown in FIG. The spring 70 constitutes a force means for keeping the spool 58 in its original position.

When the excitation current is supplied to the coil 100, the coil 100 is pushed out of the yoke 103 by the magnetic field of the magnet 106, and the spool 58 is advanced into the valve hole 52. A force is applied to the spool 58 in the direction of communicating the control pressure port 78 with the high pressure port 72, that is, a control force in the opposite direction to the operating force generated based on the application of control pressure by the reaction force pin 68. Control force is coil 1
00 is proportional to the magnitude of the excitation current. This spool 58
starts moving forward when the following equation holds, ignoring the frictional force.

FS=IzKz=r2 HHHHit) However, FS: Thrust force I2 of force smoke 98: Excitation current to coil 100 2: Proportionality constant f2 Set load of spring 70 Further, the housing 50 is provided with an electromagnetic on-off valve 120. ing. The electromagnetic on-off valve 120 has a valve chamber 122 formed in the housing 50, and a valve element 12B made of a magnetic material is disposed in the valve chamber 122 so as to be movable in the axial direction.

The valve chamber 122 communicates with the high pressure port 72 through a liquid passage 130 and with the accumulator 26 through a liquid passage 132 .

A valve seat 134 is provided between the valve chamber 122 and the liquid passage 132. Further, a coil 136 is provided around the valve 128.
A spring 138 is provided, and the biasing force of the spring 138 causes the valve element 128 to normally sit on the valve seat 134 to isolate the high pressure port 72 from the accumulator 26. On the other hand, when the excitation current is supplied to the coil 136, the valve element 128 is moved away from the valve seat 134 against the biasing force of the spring 138, and the electromagnetic on-off valve 120 is opened.

The electromagnetic on-off valve 120 opens when the following equation (2) is satisfied, and closes when the following equation (3) is satisfied.

πd2PA/4+IoK1-fI (2) 1, = f, (3) where, d: Diameter PA of the opening of the liquid passage 132 to the valve seat 134:
Hydraulic pressure f1 of accumulator 26 Set load To, It of spring 138: To excitation current to coil 136: Proportionality constant As shown in FIG. It is connected in series to the working amplifier 34 so that the current of the working amplifier 34 is simultaneously supplied to both the coil 136 and the coil 100. Open/close valve 12
0 is shown separately from the electromagnetic hydraulic control valve 24). That is, in this embodiment, the controller 30 and the operating amplifier 34 also function as on-off valve control means, and the current value I that satisfies the above equations (1), (2), and (3). , r
In order to establish the relationship O<Io<It<Iz between l and 12, + and 2 are added to the proportionality constant, set load fz of spring 7o, set load f of spring 138, f diameter of opening of valve seat 134, etc. The size is set. Therefore, when the excitation current I is linearly increased and then linearly decreased as shown in FIG. This is done at the timing shown in FIG. Neither the electromagnetic on-off valve 120 nor the electromagnetic hydraulic pressure control valve 24 operates with a small current supplied based on small noise, etc., and the electromagnetic on-off valve 120 opens before the electromagnetic hydraulic control valve 24 starts operating. , it closes after the electromagnetic hydraulic control valve 24 completes its operation.

In the hydraulic brake device configured as described above, no current is supplied from the operating amplifier 34 during normal times when the brake pedal 20 is not depressed. Therefore, the electromagnetic on-off valve 120 is closed, cutting off communication between the high pressure port 72 and the accumulator 26, as shown in FIG. Further, the electromagnetic hydraulic pressure control valve 24 is configured so that the spool 58 is connected to the first
In the original position shown in the figure, in this state the second low pressure port 7
6 and the control pressure bow 1-78 are communicated via an annular chamber 80, and the hydraulic pressure in the wheel cylinders 10-16 is equal to the atmospheric pressure, which is the hydraulic pressure in the reservoir 36.

When the depression operation of the brake pedal 20 is started from the state 1, the depression force is detected by the depression force sensor 28, and the excitation current I is transmitted through the controller 30 to a magnitude corresponding to the depression force.
is supplied from the operational amplifier 34 to the coils 100 and 136. At this time, both the electromagnetic on-off valve 120 and the electromagnetic hydraulic pressure control valve 24 do not operate until the current value I reaches 10.

The current value I is I. If the value exceeds the limit, the electromagnetic on-off valve 120 opens, and the high pressure port 72 of the electromagnetic hydraulic pressure control valve 24 and the accumulator 2
6 is brought into communication with the high pressure port 72, and the hydraulic pressure of the high pressure port 72 is increased. Then, when the current value I rises to 12, the spool 5
8 is advanced, communication between the second low pressure port 76 and the control pressure port 78 is cut off, and when the spool 58 is further advanced, the high pressure port 72 and the control pressure port 78 are brought into communication via the annular chamber 82. . Due to this communication, the hydraulic pressure P of the control pressure port 78 increases, and the hydraulic pressure of the wheel cylinders 10 to 16 is controlled.

When the brake 20 is released, the current value ■ supplied from the operating amplifier 34 is reduced based on a signal from the controller 30, and the forward force of the spool 58 becomes smaller than the reaction force, causing the spool 58 to move forward. The high pressure port 72 and the control pressure port 78 are disconnected from each other. When the current value I decreases to 12, the spool 58 returns to its original position, the second low pressure port 76 and the control pressure port 78 are brought into communication, and the hydraulic pressure P of the control pressure port 78 becomes zero.

Furthermore, if the current value I decreases to 11, the electromagnetic on-off valve 12
0 is closed and high pressure port 72 is isolated from accumulator 26.

In addition, during travel control, regardless of whether the brake pedal 20 is depressed or not, a command from the travel control computer 44 is transmitted to the controller 30, so that an excitation current is supplied from the operating amplifier 34, and in the same way, the wheel cylinder 10 to 16 hydraulic pressure controls are performed.

As detailed above, in this embodiment, the coil 10
0, the electromagnetic on-off valve 120 opens before the spool 58 moves, and the potential amount-off valve 120 closes after the spool 58 returns to its original position. When the electromagnetic hydraulic pressure control valve 24 is inactive, the high pressure port 72 is cut off from the accumulator 26, and the spool 56 and valve hole 52 are disconnected.
The hydraulic pressure in the annular groove 82 is reduced by leakage from the gap between the annular groove 82 and the annular groove 82. Therefore, even if the electromagnetic hydraulic pressure control valve 24 remains inactive, the spool 5
Since there is no hydraulic imbalance around the operating amplifier 34 and hydraulic lock is prevented from occurring, the operating amplifier 34
The spool 5B can move smoothly in response to the supply of current from the spool 5B. In the electromagnetic hydraulic pressure control device of this embodiment, even after the electromagnetic hydraulic pressure control valve 24 is kept inactive for a long time, the relationship between the current and the hydraulic pressure of the control pressure port 78 is maintained in the upper part of FIG. The result is similar to the graph shown in , and the delay in the rise of the control hydraulic pressure is satisfactorily eliminated.

In this embodiment, the electromagnetic on-off valve 120 is integrally provided with the housing 50 of the electromagnetic hydraulic pressure control valve 24, so the entire device can be made smaller, and the number of parts is reduced, resulting in a cost reduction effect. can get.

Furthermore, in this embodiment, the electromagnetic hydraulic pressure control valve 24 and the electromagnetic on-off valve 120 are connected in series to the operating amplifier 34, so that the electromagnetic on-off valve 120 is always opened after the electromagnetic on-off valve 120 opens as the excitation current increases. The electromagnetic hydraulic pressure control valve 24 opens, and after the electromagnetic hydraulic pressure control valve 24 closes, the electromagnetic on-off valve 120 closes. Therefore, compared to the case where the operating amplifier of the electromagnetic on-off valve 120 is provided separately from the operating amplifier 34 of the electromagnetic hydraulic pressure control valve 24 to open and close, the structure of the entire device is simplified, and the electromagnetic hydraulic pressure control device This has the effect of improving reliability.

Furthermore, even when automatically controlling the brakes independently of the depression operation of the brake pedal 20, such as running control or anti-skid control, the electromagnetic hydraulic pressure control valve 24 and the electromagnetic on-off valve 120 are connected in series as in this embodiment. If connected to the operating amplifier 34, the electromagnetic hydraulic pressure control valve 24 and the electromagnetic on-off valve 1 are activated based on command signals from the travel control computer 44, etc.
The electromagnetic on-off valve 120 can be operated together with the electromagnetic on-off valve 120.
Moreover, compared to the case where a separate control means connected to the travel control computer 44 or the like is provided, the structure of the device can be simplified.

Although Fig. 2 depicts the electromagnetic hydraulic control valve and the electromagnetic on-off valve separately for ease of understanding, they may actually be provided separately. The valve operation amplifier may be connected to the controller of the electromagnetic hydraulic pressure control valve, and the electromagnetic hydraulic pressure control valve and the electromagnetic on-off valve may be controlled according to the respective supplied currents. , it is sufficient to prevent hydraulic locking of the spool.

In addition, various modifications may be made based on the knowledge of those skilled in the art.

The invention can be practiced in modified forms.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a spool type hydraulic pressure control device according to an embodiment of the present invention. FIG. 2 is a system diagram of a hydraulic brake device having the above hydraulic pressure control device. FIG. 3 is a graph showing the relationship between excitation current and controlled hydraulic pressure in the above device, and FIG. 4 is a graph showing problems with the conventional hydraulic pressure control valve.

Claims (1)

[Claims] a housing having a high pressure port, a low pressure port, and a control pressure port; a housing slidably and substantially liquid-tightly fitted to a valve hole in the housing; a spool that selectively communicates with the spool; a biasing means that biases the spool to a position that blocks the control pressure port from the high pressure port; and a force based on the hydraulic pressure of the control pressure port that is applied to the spool. , an actuating force generating means for generating an actuating force to actuate the spool in a direction that isolates the control pressure port from the high pressure port, and an excitation coil, and the actuating force of the actuating force generating means is controlled by controlling the current supplied to the excitation coil. In the spool-type electromagnetic hydraulic control device, the control force applying means applies a control force in the opposite direction to the spool, and an on-off valve is connected to the high pressure port, and the control force applying means opens and closes the control force when the control force is applied. A spool-type electromagnetic hydraulic pressure control device characterized by being provided with an on-off valve control means that opens the valve and closes it when the valve is not applied.