JP2577194B2 - Hydraulic pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pressure control device, and more particularly, to a device for controlling a speed of raising and lowering a hydraulic pressure (strictly speaking, a flow speed).

[0002] The hydraulic control device of the present invention can be used for all hydraulic devices that require pressure and flow control, but is particularly effective when electronically controlling the hydraulic pressure of a vehicle brake device. For the sake of convenience, a description will be given below of an example in which the present invention is applied to a brake device, particularly, an anti-lock device.

[0003]

2. Description of the Related Art In an electronically controlled brake device (such as an antilock device), a solenoid valve is used almost without exception as a hydraulic control element.

However, a general solenoid valve has a voltage, temperature, input hydraulic pressure, output hydraulic pressure at that time even if the duration (open command time or close command time) of the step-down command or the step-up command is constant. Although the step-down amount or the step-up amount (passing liquid amount) is different due to the above, there is no function of detecting the change of the step-up / step-down amount and feeding it back. Therefore, the change of the step-up / step-down amount is separately detected. Unless corrected, it is difficult to expect accurate control.

On the other hand, Japanese Utility Model Publication No. 52-54021 discloses that a liquid flow between an input port and an output port is passed through an orifice and a differential pressure across the orifice is opposed to a spool driven by an electric / force converter. A flow regulating valve is shown in which the output of the electric / force converter and the differential pressure across the orifice are balanced in such a way that the regulating pressure corresponds to the electric command.

[0006] Although this regulating valve can be expected to provide precise and precise control, the following disadvantages arise in a brake device that performs antilock control.

[0007]

That is, during normal braking, it is necessary to allow the brake fluid to pass through without restriction from the viewpoint of responsiveness so that the rise and fall of the pressure are accelerated. However, in the flow regulating valve disclosed in the above-mentioned publication, the controlled liquid always passes through the orifice when the liquid at the time of normal braking passes, so that the rate of pressure rise and fall is determined by the diameter of the orifice, and rapid pressure rise and fall cannot be expected. In addition, if the diameter of the orifice is increased, the speed of raising and lowering the pressure is increased to some extent. However, in this case, the control accuracy in the small flow velocity region becomes coarse.

Accordingly, the present invention is directed to a liquid which allows a liquid to be controlled to flow at a large flow rate without any restriction before the start of control without increasing the diameter of the orifice, that is, without deteriorating control accuracy in a low flow velocity range. It is an object to provide a pressure control device.

[0009]

To solve the above-mentioned problems, a hydraulic control device according to the present invention comprises a device dedicated to boosting control provided with a boosting bypass and a device dedicated to step-down controlling provided with a step-down bypass. Are divided into

The former device has a housing having an input port and an output port, a spool inserted slidably in the housing, and a first formed between the housing at each end of the spool. And a second liquid chamber, a passage communicating between the two liquid chambers, a fixed orifice provided in the passage, a spring for holding the spool at an initial position, and an axial driving force corresponding to an electric command amount to the spool. An output port communicating with the second liquid chamber, a connection state between the input port and the first liquid chamber changes by displacement of the spool, and the controlled liquid passes through the fixed orifice portion. A hydraulic pressure control device configured to generate a differential pressure that balances a force obtained by subtracting a spring force from a transducer output before and after the fixed orifice when flowing through the fixed orifice. And on its place in the passage A fixed orifice is provided inside the spool, a surface passage that reaches the outer periphery of the spool through the passage in the spool on the first liquid chamber side of the fixed orifice is provided in the spool, and a position where the surface passage communicates with the input port is defined as a first position. The input port and the output port when the spool is moved to the input port side (the first position side) by a certain distance from the transition point from the first position to the second position with the position blocked from the input port being the first position and the second position. Is formed by processing a casing or a casing and a spool to provide a pressure-boosting passage (claim 1).

Further, the latter device eliminates the input port and the pressure-boosting bypass of the device of the first aspect, and instead has a discharge port and a position where the surface passage of the spool is shut off from the discharge port, and a discharge port. A step-down bypass path that connects the outlet and the output port when the spool moves to the outlet side (third position side) by a certain distance or more from the transition point from the second position to the third position with the position communicating with the third position. (Claim 2).

[0012]

According to the first aspect of the present invention, the device according to the first aspect is connected between the input port and the output port when the step-up bypass is open, while the second type of apparatus is connected between the output port and the output port when the step-down bypass is open. In this case, the liquid can pass freely without restriction, and the responsiveness can be prevented from deteriorating by increasing and decreasing the pressure during normal braking of the brake device at a large flow rate.

Also, in any of the devices, once the control is started, the flow velocity of the liquid to be controlled, that is, if the load rigidity is fixed, the raising / lowering speed, which is a time differential value of the output hydraulic pressure, is automatically changed to an electric voltage. Mechanical feedback is applied in response to the command. This is for the following reason.

Now, the liquid from the input port to the output port or from the output port to the discharge port passes through the fixed orifice in the movable spool every time the pressure rises and falls, and the pressure difference before and after the fixed orifice is increased each time the liquid passes. Occur. The amount of liquid passing through the fixed orifice is determined by this pressure difference.
It is determined by the balance between the force of the spring and the driving force of the electric / force converter, and is formed by an overlap between the surface passage of the spool and the input port or the discharge port on the housing side so that this pressure difference is maintained. The opening of the variable orifice is automatically adjusted by the displacement of the spool. Therefore, the flow velocity (step-up / step-down speed) of the liquid flow reaching the brake or the like or returning from the brake or the like eventually corresponds to the electric command amount, thereby enabling the step-up / step-down speed control directly connected to the control command. As a result, the overshoot is essentially smaller than that in which the output side hydraulic pressure itself corresponds to the electric command, the hydraulic vibration is suppressed, and the controllability is excellent.

[0015]

FIG. 1 shows a first embodiment of a hydraulic control device according to the present invention.

As shown in the figure, the hydraulic control device 10 has a spool 12 movable in the axial direction inside a housing 11. Further, a first liquid chamber A is provided between one end of the spool and the housing, and a second liquid chamber B is provided between the other end and the housing.
A liquid chamber A is connected to the spool 12 through a fixed orifice 15.
An internal passage communicating with B and a surface passage extending from the internal passage to the outer peripheral surface on the liquid chamber A side of the fixed orifice 15 are provided. In actual manufacturing, the spool 12 can be inserted directly into the housing 11, or a sleeve can be provided inside the housing 11 and the spool 12 can be inserted into the sleeve.

The spool 12 is held at an initial position (first position) by the force of a spring 18.

The output of the electric / force converter 20 drives the spool against the force of the spring. The electric / force converter 20 is of a type that generates a driving force on the spool driver 19 by applying a current (voltage) to the coil. When the applied current (voltage) is zero, the driving force generated by the driver 19 is of course zero.

Many types of such electric / force converters 20 are known, and various combinations such as a coil and a permanent magnet, a coil and an electromagnetic force, a permanent magnet and an electromagnet, an electromagnet and an iron core, etc. Although widely used in equipment, it is desirable to select an apparatus that has a small change in force due to a stroke as the apparatus used in the present invention.

Now, considering the target system (electronic control brake system) of the apparatus of the present invention, a particularly large flow rate is required because the input operation during normal braking before the control (in this case, antilock control) is started. It is time to increase the brake pressure at a high speed.

However, in this case, Japanese Utility Model Publication No. 52-54
If the flow regulating valve disclosed in Japanese Patent No. 021 is used,
Since there is a restriction that the opening area of the fixed orifice cannot be made too large from the viewpoint of ensuring controllability in a small flow velocity region, a large flow velocity (large pressure rising velocity) cannot be expected.

Also, for example, in the pressure-reducing process of the antilock control, the output pressure is made to flow to the discharge port to reduce the pressure.
After the pressure drops below a certain pressure, the flow rate, that is, the step-down speed cannot be secured until then due to the restriction due to the opening area of the fixed orifice, and the step-down speed decreases more and more as the step-down further proceeds.

In order to perform the antilock control precisely, it is desirable to secure a certain step-down speed even in a low output pressure region. However, for this purpose, the diameter of the fixed orifice must be increased. In particular, the controllability in a small flow velocity region deteriorates.

Therefore, when the spool is at the initial position, the hydraulic pressure control device 10 shown in FIG.
And the spool moves from the initial position to the second liquid chamber B side.
A step-up bypass 23 is provided in which the communication is cut off when the movement is performed by (l <l ₁ ).

The control device 10 includes an electric / force converter 20
Is zero, the boost bypass path 23 is open. Accordingly, the pressure difference between both ends of the fixed orifice 15 is substantially zero, and the flow velocity of the orifice is substantially zero because the communicating flow velocity is proportional to the square root of the differential pressure. Position or the initial position,
During the non-control period before the electric / force converter 20 starts outputting, the non-control liquid flows directly from the input port 13 to the output port 16. That is, in this state, there is no flow velocity limitation by the fixed orifice, and an arbitrary raising / lowering speed can be obtained.

When the control is started, the pressurizing bypass passage 23 is closed and the pressurizing liquid passes through the fixed orifice, so that the maximum flow rate is small, but the characteristics of the variable flow rate control by the above-described mechanism are utilized. Excellent controllability is obtained.

Hereinafter, the mechanism of flow rate control will be described in more detail.

Now, based on the boost command, the electric / force converter 2
0, a current (voltage) is applied to the spool 12
Moves to the right in the figure to connect the input port 13 and the surface passage 14, the supply liquid reaching the output port 16 tends to flow from the right or left through the fixed orifice 15. The flow velocity at this time is determined by the differential pressure across the fixed orifice 15. At the intersection of the input port 13 and the surface passage 14, a variable orifice whose passage area (opening) changes depending on the connection between the two is formed. The differential pressure is affected by the opening of the variable orifice. That is, the spool 12 moves to the right 13
When the opening degree of the variable orifice between 14 becomes large, the hydraulic pressure in the spool on the right side of the fixed orifice 15 rises and the spool tries to return to the left, and conversely, the spool 12 moves to the left and the opening degree of the variable orifice becomes When it becomes smaller, the flow rate through the variable orifice becomes smaller than the passage liquid amount in the fixed orifice 15, and the spool tends to move to the right by the force of the electric / force converter.

The force obtained by multiplying the difference between the hydraulic pressure on the left side and the hydraulic pressure on the right side of the fixed orifice 15 by the spool area by this automatic balancing action is equal to the force generated by the electric / force converter 20 and the spring 18.
And the amount of liquid passing through the fixed orifice 15 is equal to the hydraulic pressure difference between the left and right orifices, that is,
This corresponds to the pressure obtained by subtracting the force obtained by subtracting the force of the spring 18 from the force generated by the electric / force converter 20 by the cross-sectional area of the spring.

In FIG. 1, the pressurizing bypass passage 23 is composed of three passages 23a and 23b and a spool outer peripheral groove 23c. However, as shown in FIG.
Is provided directly with the second liquid chamber B, and the open end of the passage with respect to the liquid chamber B is closed by moving the spool 12 from the initial position by 1 so that the bypass path 23 can be simplified.

FIG. 3 shows a device dedicated to step-down control in which the input port 13 of the apparatus of FIG. 1 is eliminated and a discharge port 17 is provided instead, and a step-down bypass 24 is provided instead of the step-up bypass of FIG. Is shown.

The passage 24a in the housing and the passage 24 on the spool side
In the step-down bypass passage 24 composed of the two members b, the surface passage 14 and the discharge port 17 form a variable orifice between them, and the step-down control via the fixed orifice 15 Is not yet open while performing the same mechanism (only the direction is different). However, if the output pressure is smaller than the force obtained by subtracting the force of the spring 18 from the force of the electric / force converter 20, that is, the output pressure is smaller than the force corresponding to the desired pressure reduction speed, the above-described pressure is considered as zero when the pressure at the outlet is considered to be zero. It is impossible to maintain the pressure difference between both ends of the spool in accordance with the difference in force. For this reason, when the spool 12 moves to the right in the drawing and the movement amount of 12 exceeds l ₃ (l ₃ > l ₂ ), The step-down bypass 24 is opened, and the outlet 17 and the output 16 are connected via the bypass.

In this state, the step-down speed is out of the constraint of the fixed orifice 15, whereby the output pressure quickly drops toward substantially zero pressure. And this state
It continues until the output of the electric / force converter 20 becomes smaller than the force of the spring 18. By using this device, it is possible to improve the controllability of the step-down pressure in the vicinity of the output hydraulic pressure 0.

[0034] In addition to the above, the following devices have been devised in the illustrated device. That is, the spring 1 is
Eight adjustment screws 25 are provided. This is for adjusting the balance between the output of the electric / force converter 20 and the force of the spring 18 when a hydraulic pressure holding command is issued, and the surface passage 14 of the spool 12 is The balance is adjusted at the second position not communicating with the outlet 17 so that the spool 12 is maintained at that position.

This adjustment may be performed by a method using an adjustment screw shown in the drawing, or a method in which a shim to be combined is selected in advance according to the state of the spring, and the shim is sandwiched between the spring and the housing or between the spring and the spool. Further, the output of the electric / force converter 20 may be adjusted instead of the spring force.

The output of the electric / force converter 20 may be adjusted by adding a resistor, selecting a resistance value of the added resistor, adjusting a variable resistor, or the like.

If the electronic control unit for issuing an electric command to the controller 20 and the control device 10 are used in a fixed combination in a one-to-one correspondence, the constants in the electronic control unit are adjusted at the time of shipment (in this case, for example, writing Possible PR
OM or a rewriteable so-called EEPROM or the like) can be used, but usually, an arbitrary combination of the electronic control unit and the control device is required, so that there are few cases where this method can be used.

If constant adjustment is not possible at the time of shipment, it is possible to learn and store an appropriate adjustment value while making the electronic control unit judge the control situation during actual use. In this case, no special measures are required if the target system includes a pressure sensor. However, in the case where the pressure sensor is omitted (in most brake systems for automobiles, there is a margin for providing the pressure sensor in terms of cost). If there is a certain degree of misunderstanding under certain easy-to-predict conditions by checking whether the control of the entire system has been executed as expected, the value to be adjusted little by little in the direction to correct it is determined. Change and store the new value. If the initial value at the time of shipment is set to a value near the average value of the manufacturing variation, adjustment to the optimum value can be performed with a small number of corrections.

[0039]

As described above, the first aspect of the present invention is as follows.
Is a type of pressure control device that generates a differential pressure across the orifice in the movable spool, balances this differential pressure with the output of the electric / force converter, and controls the speed at which the pressure rises and falls to correspond to the electric command. Until the pressure control is started, the device is provided with a pressure boost bypass passage through which the liquid passes without limitation, and the device according to claim 2 is controlled by a device dedicated to pressure reduction control in which pressure control is performed by the same mechanism. A step-down bypass that opens and allows liquid to pass through without restriction when the pressure is not high or when the output pressure is close to 0 allows liquid passage at a high flow rate and high-precision pressure control in a small flow rate range. Therefore, for example, when used in a vehicle brake device, the brake fluid flows back and forth between the hydraulic pressure source and the vehicle brake without restriction during normal control, and precise pressure control is performed when depressurizing or repressurizing the antilock. When you do It is possible that Tsu, its use is expanding.

The hydraulic control device of the present invention is particularly suitable for a vehicle brake in which responsiveness, control roughness and the like are important, but it is suitable for general hydraulic equipment [in particular, a hydraulic load device (such as a cylinder)]. Hydraulic equipment in which the amount of pressurized liquid sent out to the hydraulic pressure device and the pressure rise in the hydraulic load device have a fixed relationship] can also be used as a simple flow control valve. The effectiveness of the device is sufficiently exhibited with respect to the above factors.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a hydraulic pressure control device of the present invention.

FIG. 2 is a cross-sectional view showing a modified example of the boosting bypass path of the apparatus of FIG.

FIG. 3 is a cross-sectional view of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hydraulic pressure control apparatus 11 Housing 12 Spool 13 Input port 14 Surface passage 15 Orifice 16 Output port 17 Discharge port 18 Spring 19 Driver 20 Electric / force converter 23 Step-up bypass path 24 Step-down bypass path 25 Adjustment screw

Claims (2)

(57) [Claims] 1. A casing having an input port and an output port, a spool inserted in the casing slidably in an axial direction,
First and second liquid chambers formed between each end of the spool and the housing, a passage communicating between the two liquid chambers, a fixed orifice provided in the passage, and the spool held at an initial position. A spring, and an electric / force converter for applying an axial driving force to the spool in accordance with an electric command amount, wherein the output port communicates with the second liquid chamber, and the input port and the first liquid chamber are connected by spool displacement. Is changed so that when the controlled liquid flows through the fixed orifice portion, a differential pressure is generated before and after the fixed orifice, which balances the force obtained by subtracting the spring force from the transducer output. In the pressure control device, the passage for communicating the first and second liquid chambers and the fixed orifice disposed in the passage are provided inside the spool, and the first orifice communicates with the passage in the spool on the first liquid chamber side with respect to the fixed orifice. Around the spool A transition point from the first position to the second position, wherein a position where the surface passage communicates with the input port is a first position, and a position where the surface path is blocked from the input port is a second position. A hydraulic pressure control characterized in that a step-up bypass path connecting the input port and the output port when being moved to the input port side (first position side) for a certain distance or more is provided in the casing or the casing and the spool and provided. apparatus. 2. A housing having an output port and a discharge port, a spool inserted slidably in the housing in the axial direction, and a first and a second formed between the housing at each end of the spool.
A liquid chamber, a passage communicating between the two liquid chambers, a fixed orifice provided in the passage, a spring for holding the spool at an initial position, and an electric / force for applying an axial driving force to the spool in accordance with an electric command amount. A converter, wherein the output port communicates with the second liquid chamber, and a connection state between the discharge port and the first liquid chamber is changed by displacement of the spool, and the controlled liquid flows through the fixed orifice portion. When the hydraulic pressure control device is configured to generate a differential pressure that balances a force obtained by subtracting a spring force from a transducer output before and after the fixed orifice, the first and second fluid chambers communicate with each other. The fixed orifice disposed in the passage is provided inside the spool, and a surface passage that reaches the outer periphery of the spool through the passage in the spool closer to the first liquid chamber than the fixed orifice is provided in the spool. With the position blocked from the discharge port as the second position and the position communicating with the discharge port as the third position, the spool is positioned at a certain distance or more from the transition point from the second position to the third position on the discharge port side (the third position side). A hydraulic pressure control device characterized in that a step-down bypass, which connects a discharge port and an output port when moved, is provided in a casing or a casing and a spool.