JP2001263531A - Solenoid valve control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve control accuracy by correcting according to a pressure difference between front and rear solenoid valves, namely, changes in the fluid force acting on a valve element. SOLUTION: This solenoid valve control device is provided with a pressure intensifying solenoid valve 41 provided in a main passage 20, a pressure reducing solenoid valve 42 provided in a drain circuit 50, and a control unit 70 controlling a pulse width modulation relative to the solenoid valves 41 and 42 and adjusting their openings. This control device is also provided with a differential pressure detecting means for detecting the front/rear differential pressures of the respective solenoid valves 41 and 42 and the control unit 70 is so constituted as to calculate the differential pressure correction gain based on the front/rear differential pressures found by the differential pressure detecting means and to correct the output to the solenoid valves 41 and 42 based on the differential pressure correction gain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve control device for controlling the opening and closing of a solenoid valve provided in the middle of a flow path through which a fluid flows, and more particularly to a brake control device for controlling a wheel cylinder pressure in an automobile. It relates to a device suitable for application.

[0002]

2. Description of the Related Art Conventionally, as a solenoid valve control, there has been known a brake control device for controlling a braking force by increasing, maintaining, and reducing a wheel cylinder pressure to obtain a desired pressure. In recent years, various types of brake control have been proposed (for example, Japanese Patent Laid-Open No. 10-2787).
No. 64). In such a brake control device, control accuracy as high as possible is required. Therefore,
The present applicant has applied pulse modulation control (hereinafter referred to as PWM) to an electromagnetic valve.
Control), and a brake control device that detects a regenerative current generated in a coil of an electromagnetic valve and performs feedback control based on the detected value has been proposed (Japanese Patent Application No. 11-11420). This invention by the applicant of the present application
Since the feedback control can be performed based on the output state (valve open state) of the solenoid valve, the responsiveness is improved with respect to the conventional feedback control based on the wheel speed, which is the result of the hydraulic pressure control by the solenoid valve. It had the feature that it could be done.

[0003]

However, as a result of further research by the present inventors, the following problems to be solved have been found in order to improve control accuracy.
That is, various forces other than the electromagnetic force act on the valve body of the electromagnetic valve provided in the conduit connecting the hydraulic pressure source and the wheel cylinder, and the valve opening is determined by the balance of these forces. For example, in the case of a normally closed solenoid valve, in the valve closing direction, a negative pressure generated in accordance with the flow rate of the brake fluid or a biasing force for biasing the valve body in the valve closing direction. Acts in the valve opening direction, and a fluid force based on a suction force of the solenoid and a pressure difference between upstream and downstream of the solenoid valve acts. Here, when considering the fluid force based on this pressure difference, the pressure difference is large before and immediately after the valve is opened, but becomes smaller thereafter, so that this fluid force also becomes smaller as the pressure difference decreases. For this reason, when the solenoid valve continues to open for a relatively long time, or when the pressure upstream of the conduit is originally small, it becomes difficult to open the solenoid valve, and it becomes difficult to generate a desired pressure. Therefore, if the pressure difference before and after the solenoid valve becomes small as described above, the valve body will not be arranged at a position corresponding to the pulse width (by the PWM control) determined by the control unit, causing a shift in control, and This makes it difficult to perform the feedback control.

The present invention has been made in view of the above-mentioned problems, and performs a correction in accordance with a pressure difference before and after a solenoid valve, that is, a change in fluid force acting on a valve body.
The purpose is to further improve the control accuracy.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a fully closed state in which a flow path is provided in the middle of a flow path through which a fluid flows and a fully closed state in which the flow path is closed. And a control means for performing pulse width modulation control on the electromagnetic valve to adjust the opening thereof, wherein the electromagnetic valve is upstream and downstream of the electromagnetic valve in the flow path. Differential pressure detecting means for detecting a differential pressure between the front and rear pressures, the control means calculating a differential pressure correction gain based on the front and rear differential pressure obtained by the differential pressure detecting means, The means is configured to correct the output to the solenoid valve based on the correction gain. According to a second aspect of the present invention, in the solenoid valve control device according to the first aspect, the differential pressure correction gain is determined based on a fluid force in which the front-rear differential pressure acts on the valve body in the valve closing direction and the valve opening direction. It is characterized by being compatible.

According to a third aspect of the present invention, in the solenoid valve control device according to the first or second aspect, the flow path includes a supply flow path connecting a wheel cylinder and a hydraulic pressure source in a vehicle brake device; At least one of a drain flow path connecting a cylinder and a brake fluid recovery side, wherein the control means executes control of the solenoid valve to control a wheel cylinder pressure to a desired pressure based on an input relating to a running state. It is characterized by having a configuration. According to a fourth aspect of the present invention, in the solenoid valve control device according to the third aspect, a valve position for generating a regenerative current when the solenoid valve is energized and estimating a position of the valve body based on the regenerative current. Estimating means is provided, and the differential pressure detecting means includes wheel cylinder pressure estimating means for estimating a wheel cylinder pressure based on the position of the valve element estimated by the valve position estimating means. It is characterized in that the differential pressure is estimated based on the pressure difference between the pressure of the hydraulic pressure source and the estimated wheel cylinder pressure and the pressure difference on the brake fluid recovery side. According to a fifth aspect of the present invention, in the solenoid valve control device according to the fourth aspect, the solenoid valve is a normally-open pressure increasing solenoid valve provided in the supply passage, and the differential pressure detecting means is ,
When the pressure of the hydraulic pressure source is PS and the estimated wheel cylinder pressure is PL, the pressure difference Pd_i across the pressure-intensifying solenoid valve is represented by Pd_i.
= PL-PS, and the correction gain Ki for the pressure-intensifying solenoid valve is further obtained by calculating Ki = αi × PS / Pd_i (where αi is a constant). According to a sixth aspect of the present invention, in the solenoid valve control device according to the fourth or fifth aspect, the solenoid valve is a normally-closed pressure reducing solenoid valve provided in the drain passage, and the differential pressure detecting means Is obtained by calculating the pressure difference Pd_o before and after the pressure reducing solenoid valve by calculating Pd_o = PL, where PL is the estimated wheel cylinder pressure, and furthermore, a correction gain Ko for the pressure reducing solenoid valve.
Is obtained by calculating Ko = αo × PS / Pd_o (where αo is a constant). According to a seventh aspect of the present invention, in the solenoid valve control device according to the fifth or sixth aspect, the control means outputs a control signal PSIGi to the pressure-intensifying solenoid valve when the target pressure of the wheel cylinder is Pt. PSIGi = βi × Ki × (Pt−PL) (where β
i is a constant). According to an eighth aspect of the present invention, in the solenoid valve control device according to the sixth or seventh aspect, the control means sets the target pressure of the wheel cylinder to Pt.
And the control signal PSIGo for the pressure reducing solenoid valve
PSIGo = βo × Ko × (Pt−PL) (where β
o is a constant).

[0007]

According to the present invention, when the control means outputs a control signal to the solenoid valve, the control means detects a differential pressure between upstream and downstream of the solenoid valve which is detected by the differential pressure detecting means. Based on the differential pressure correction gain, the output to the solenoid valve is corrected based on the differential pressure correction gain. Therefore, in the invention described in all claims of the present application, the solenoid valve corrects the electromagnetic force for operating the valve body in accordance with the change in the fluid force acting on the valve body according to the differential pressure, and the output of the control means is controlled. The effect that the control accuracy of the valve body position can be improved can be obtained.

[0008] In the invention according to claim 3, the control means includes:
Based on the running state detected by the running state detecting means, control is executed to generate a braking force by controlling the wheel cylinder pressure as needed. In controlling the wheel cylinder pressure, the solenoid valve provided in at least one of the supply flow path connecting the wheel cylinder to the hydraulic pressure source and the drain flow path connecting the wheel cylinder to the brake fluid recovery side is controlled. I do. That is, the wheel cylinder pressure can be increased by opening the electromagnetic valve provided in the supply flow path, and the wheel cylinder pressure can be reduced by opening the electromagnetic valve provided in the drain flow path. In the control of the wheel cylinder pressure by such an electromagnetic valve, the above-described correction according to the differential pressure is performed to improve the control accuracy.

According to the present invention, in controlling the wheel cylinder pressure, the position of the valve element is estimated by the valve position estimating means, and the position of the valve element is adjusted by the wheel cylinder pressure estimating means of the differential pressure detecting means. The pressure difference between the solenoid valve and the estimated wheel cylinder pressure is estimated based on the pressure difference between the hydraulic pressure source and the estimated wheel cylinder pressure and the pressure difference between the brake fluid recovery side and the estimated wheel cylinder pressure. Therefore,
There is no need for a pressure sensor for actually detecting the pressure difference between the front and rear of the solenoid valve, and the effect that the apparatus can be constructed at low cost is obtained. In addition, since the position of the valve body is estimated by the regenerative current, the estimation timing is earlier than when the estimation is performed based on the actual control hydraulic pressure output, and control responsiveness can be improved accordingly.

In the present invention, the differential pressure is corrected by the correction gain and the gain by which the control signal is multiplied is corrected. Therefore, feedback correction is performed, and the robustness is excellent. Because the correction gain is used,

Embodiments of the present invention will be described below with reference to the drawings. In describing the embodiments, a case where the solenoid valve control device of the present invention is applied to a brake control device will be described as an example. (First Embodiment) FIG. 1 is an overall view showing a brake control device according to a first embodiment. The brake control device according to the first embodiment is of a so-called brake-by-wire type in which the brake pedal BP and the wheel cylinder WC are not mechanically linked.

The wheel cylinder WC is connected to a pump P as a brake fluid pressure source and an accumulator 100 for accumulating the discharge pressure of the pump P via a main passage (corresponding to a supply circuit in the claims) 20. Have been. The wheel cylinder WC is connected to the suction side of the pump P via a suction circuit 30. In the main passage 20, at a position near the pump P, a discharge valve 2 that allows the brake fluid to flow only in the pump discharge direction and prevents the backflow thereof
On the other hand, at a position near the pump P in the suction circuit 30, there is provided a suction valve 31 for flowing the brake fluid only in the pump suction direction and preventing the reverse flow. The pump P is driven by a motor M.

Further, a hydraulic pressure control valve 40 for controlling the hydraulic pressure of the wheel cylinder WC is provided in the main passage 20. The hydraulic pressure control valve 40 includes a pressure increasing solenoid valve 41 and a pressure reducing solenoid valve 42. The pressure-intensifying solenoid valve 41 is provided in the middle of the main passage 20 and communicates with the main passage 20 to supply the hydraulic pressure of the accumulator 100 to the wheel cylinder WC when not energized, and shuts off the main passage 20 when energized. And a normally open solenoid valve for stopping the supply. The pressure reducing solenoid valve 42 is provided in the middle of a drain circuit 50 connecting the main passage 20 and the suction circuit 30, and shuts off the drain circuit 50 when not energized, and opens the drain circuit 50 when energized to open the fluid in the wheel cylinder WC. It is a normally closed solenoid valve that releases pressure to the suction side of the pump P. The pressure-increasing electromagnetic valve 41 and the pressure-reducing electromagnetic valve 42 are electromagnetic valves capable of performing PWM control.

Further, an ABS unit 60 is provided near the wheel cylinder WC. That is, A
The BS unit 60 reduces, holds and increases the hydraulic pressure of the wheel cylinder WC separately from the hydraulic pressure control valve 40 when the wheels are likely to lock during braking, so that the wheels are not locked. The ABS unit 60 controls the wheel cylinder pressure so as to obtain the maximum braking force. The ABS unit 60 is located at a position closer to the wheel cylinder WC than the hydraulic pressure control valve 40 in the main passage 20 (this is referred to as a downstream position). The inflow valve 61, which is a normally-open ON / OFF valve, and the flow of the brake fluid of the wheel cylinder WC, which is provided in parallel with the inflow valve 61, allows only the flow returning to the upstream side and flows downstream. The regulating one-way valve 62 and the suction circuit 3
An outflow valve 63, which is a normally-closed ON / OFF valve, provided in the middle of 0, and a reservoir 64 provided downstream of the outflow valve 63 in the suction circuit 30, that is, on the suction side of the pump P. . Therefore, in the ABS unit 60, the inflow valve 61 is closed and the outflow valve 63 is closed to reduce the pressure, and the inflow valve 61 and the outflow valve 63 are closed to maintain the pressure.
Can be opened and the outflow valve 63 can be closed to increase the pressure.

The motor M, hydraulic control valve 40 and AB
The operation of the S unit 60 is controlled by the control unit 70. The control unit 70 corresponds to the control means, the differential pressure detecting means and the valve position estimating means in the claims, and is connected as an input means to a sensor group 80 as running state detecting means. This sensor group 80 is provided with a brake sensor 81 for detecting a braking operation on the brake pedal BP.
A wheel speed sensor 82 for detecting wheel speed, and an acceleration sensor 83 for detecting longitudinal and lateral acceleration of the vehicle
And a throttle sensor 84 for detecting the opening of the throttle valve.

In addition, as a sensor included in the sensor group 80, a regenerative current detection circuit 504 constituting a part of valve position detection means for detecting the valve position of each of the solenoid valves 41 and 42 of the hydraulic pressure control valve 40 is provided. Is provided. That is,
As shown in FIG. 2, in parallel with solenoid coils 305 provided in each of the solenoid valves 41 and 42,
The regenerative current forming circuit 501 is connected. In the regenerative current forming circuit 501, a current detecting resistor 502 and a diode 503 are provided in series.
The current is supplied in a direction that does not allow the current flowing in the coil 305 to flow through the current detection resistor 502.

A regenerative current detecting circuit 504 for detecting a regenerative current I2 is provided upstream and downstream of the current detecting resistor 502.
Is connected. That is, when the drive current I1 is applied to the coil 305 of each of the solenoid valves 41 and 42 (this is an excitation that excites the coil 305 and flows in the illustrated direction), when this energization is cut, a regenerative current forming circuit 5
01, a regenerative current I2 flows in the opposite direction to the drive current, and is detected by the regenerative current detection circuit 504.

FIG. 3 shows the relationship between these signals.
In the figure, (a) shows the output signal of the control unit 70, (b) shows the drive current I1 flowing through the coil 305, and (c) shows the regenerative current I2. As shown in this drawing, when an output signal is output from the control unit 70 (the ON portion is a duty signal), the current value of the coil 305 increases in response to the output of the ON signal, while the output signal is increased. Is switched from ON to OFF, a drive current I1 whose current value decreases is passed. On the other hand, the regenerative current I2 flows in the opposite direction to the drive current I1 when the output signal switches from ON to OFF, and its current value is high at the moment when the signal changes from ON to OFF and then gradually decreases. To change. The current value of the drive current I1 is determined by the duty ratio of the ON portion in the output signal from the control unit 70,
As the duty ratio increases, the current value increases, and as the duty ratio decreases, the current value decreases.

Although not shown, the regenerative current I2 has a different waveform due to an inductance characteristic which fluctuates in accordance with an air gap generated between the valve body and the seat surface in each of the solenoid valves 41 and 42. That is, the inductance L fluctuates according to the size of the air gap as shown in FIG. Then, as shown in FIG. 3A, the regenerative current I
2 fluctuates (ΔI in the figure) and the regenerative current I2
Changes its slope. Therefore, the regenerative current detection circuit 50
The air gap size, that is, the position of the valve body, that is, the valve lift amount can be detected from the value of the regenerative current I2 detected at step 4 or its slope. Therefore, the flow rate of the brake fluid can be estimated based on the valve lift amount, that is, the opening area, and the opening time, that is, the duty ratio, whereby the actual wheel cylinder pressure can be estimated.

Next, the contents of control by the control unit 70 will be described. The control unit 70 of the present embodiment executes the by-wire control, the automatic braking control, and the ABS control based on the input from the sensor group 80.

The by-wire control is a control for generating a braking force in the wheel cylinder WC in accordance with the operation of the brake pedal BP by the driver. In this by-wire control, first, a target pressure is obtained based on a detection value (braking signal) of the brake sensor 81, and, on the other hand, the motor M is driven to operate the pump P. The hydraulic pressure control valve 40 is operated so as to obtain the pressure, and the actual pressure which is the actual wheel cylinder pressure is calculated based on the regenerative current I2 as described above, and the feedback control is performed so that the actual pressure becomes the target pressure. Do.

In controlling the wheel cylinder pressure in the by-wire control, in the present embodiment, PWM control is performed for each of the pressure-increasing solenoid valve 41 and the pressure-decreasing solenoid valve 42.
By performing control, the valve opening of each solenoid valve 41 is controlled to a desired opening. In this case, the wheel cylinder pressure can be instantaneously increased by opening the pressure-intensifying solenoid valve 41 with the pressure-decreasing solenoid valve 42 closed, while the wheel cylinder pressure is reduced by the valve with the pressure-intensifying solenoid valve 41 closed. If the solenoid valve 42 is opened, the pressure can be reduced instantaneously. Further, by adjusting the opening of each of the solenoid valves 41 and 42 by PWM control, it is possible to slightly increase or decrease the wheel cylinder pressure.

In the present embodiment, when performing the PWM control, the regenerative current detection circuit 50 is used as described above.
The actual pressure PL is calculated based on the valve lift amount and the valve opening time (duty ratio) by detecting the valve lift amount of each of the solenoid valves 41 and 42 according to 4. However, the actual pressure is detected by providing a pressure sensor. Alternatively, the deceleration of the vehicle may be obtained based on at least one of, preferably, both the longitudinal acceleration obtained by the acceleration sensor 83 and the wheel speed obtained by the wheel speed sensor 82, and the deceleration may be determined. The actual pressure may be calculated from the throttle opening obtained by the throttle sensor 84.

Further, in the present embodiment, automatic braking control for automatically generating a braking force is performed as necessary even when the driver is not performing a braking operation, according to the running state. In this automatic brake control as well, the pump P is operated and the solenoid valves 41 and 42 are operated in the same manner as described above.
, The wheel cylinder pressure is controlled to a desired pressure. In the case of the automatic brake control, the control unit 70 calculates a target pressure based on a traveling state obtained from the sensor group 80, for example, a change in wheel speed. The automatic braking control includes an automatic braking control that automatically generates a braking force when a braking force is required in an inter-vehicle control that keeps an optimal distance between the vehicle and a preceding vehicle, and an over-steer or an over-understeer when a vehicle is turning. When the vehicle is in a state, a vehicle motion control for generating a yaw moment to generate a braking force on the desired wheel to return the vehicle to the neutral steer direction, or a control for the drive wheel to suppress the slip when the drive wheel slips. There is a torque slip control for generating power.

The ABS control is a well-known control. Briefly, the ABS control is determined based on an input from the wheel speed sensor 82 to determine whether the wheel is locked during braking, and the wheel is likely to be locked. Then, after the wheel cylinder pressure is reduced to avoid the wheel lock, the wheel speed of the target wheel is reduced by a predetermined value lower than the vehicle speed by a predetermined value, and is appropriately reduced and held so as to be the most effective speed for braking.・ Increase pressure.

The pressure reduction / holding / pressure increase in the ABS control is such that when the pressure is reduced, the inflow valve 61 is closed and the outflow valve 63 is opened, and when the pressure is reduced, both valves 61 and 63 are closed. The pressure increase is performed by opening the inflow valve 61 and closing the outflow valve 63. When the pressure is reduced, the brake fluid in the wheel cylinder WC escapes from the reservoir 64, and the brake fluid accumulated in the reservoir 64 is sucked into the pump P as needed.

Next, based on the block diagram shown in FIG.
The hydraulic pressure control and the correction control when executing the above-mentioned by-wire control and automatic brake control will be described. First, when the target pressure is obtained, a target pressure gradient, which is a gradient of the target pressure, is obtained in the target pressure premises operation unit a, and then, a judgment signal generation unit b determines a pressure increase, a pressure decrease, and a hold. A signal is formed, and this signal is output to the increase / decrease control judgment section c. On the other hand, the control pressure LPF processing unit d inputs the estimated wheel cylinder pressure (control pressure) obtained based on the detection value of the regenerative current detection circuit 504, executes desired LPF processing such as noise cut, and In a pressure deviation gradient calculating unit e, a gradient of a deviation between the target pressure and the actual pressure is obtained, and a control signal forming unit f forms a control signal. The increase / decrease control judgment section c receives the control signal and the judgment signal and sets any one of the pressure increase flag, the pressure decrease flag, and the holding flag.

The control pressure is input to a gain correction unit g having a pressure-increase valve-side correction gain calculation unit g1 and a pressure-reduction valve-side correction gain calculation unit g2.
The correction gain is determined on the basis of the differential pressure before and after. The calculation for determining the correction gain will be described later. DUTY
In the input signal calculation unit j, the duty ratio is obtained based on the control signal formed by the control signal generation unit f and the correction gain formed by the gain correction unit g, and the limit processing is performed by the limit processing unit k. Thereafter, the duty signal processing unit m forms a duty signal, and the LPF processing unit n performs low-pass filter processing such as noise cut, and outputs the duty signal to each of the solenoid valves 41 and 42.

Next, the control unit 70 described above is used.
In the control of the electromagnetic valves 41 and 42 according to the above, a correction process by the gain correction unit g which is a feature of the present embodiment will be described. Here, first, the differential pressure before and after each of the solenoid valves 41 and 42 is calculated. The differential pressure P across the pressure increasing solenoid valve 41
d_i is a hydraulic pressure PS which is a hydraulic pressure of the accumulator 100 and a control pressure P which is a hydraulic pressure of the wheel cylinder WC.
Since it is the difference from L, it can be obtained by Pd_i = PS-PL. The hydraulic pressure PS is set in advance, and the control pressure PL is estimated based on the regenerative current. On the other hand, the pressure difference Pd_o in the pressure reducing solenoid valve 42 is the difference between the control pressure PL and the pressure in the reservoir 64. If the pressure in the reservoir 64 is regarded as the atmospheric pressure, it can be obtained by Pd_o = PL. Next, a correction gain is obtained from the differential pressure. Here, assuming that the correction gain of the pressure increasing solenoid valve 41 is Ki and the correction gain of the pressure reducing solenoid valve 42 is Ko, Ki = αi · PS / Pd_i. Ko = αo · PS / Pd_o. Here, αi and αo are constants, respectively.

The correction gains Ki, Ko thus obtained
In the DUTY input signal calculating section j, the control signal generated by the control signal generating section f is corrected by the correction gain K
i, Ko, the control signal PS for the pressure-intensifying solenoid valve 41
Control signal PSIG for IGi and pressure reducing solenoid valve 42
o, and a duty signal corresponding to this is formed. Incidentally, the control signal is formed by multiplying a difference between the target pressure (Pt) and the current wheel cylinder pressure (control pressure PL) by gains βi and βo set in advance. Valve control signal P
SIGo is formed by PSIGi = βi × Ki × (Pt−PL) PSIGo = βo × Ko × (Pt−PL)

FIG. 6 is a time chart showing changes in the control pressure PL and changes in the correction gains Ki and Ko described above. As shown in this drawing, the value of the correction gain Ki of the pressure-intensifying solenoid valve 41 increases as the control pressure PL increases. That is, the pressure-increasing solenoid valve 41 is a normally-open solenoid valve, and has a structure in which the differential pressure across the valve acts in the valve closing direction. Therefore, when the control pressure PL increases, the pressure difference before and after the control pressure PL decreases, the fluid force acting in the valve closing direction decreases, and it becomes difficult to close the valve. Therefore, the gain is set so that the solenoid attraction force acting in the valve closing direction increases. to correct. On the other hand, the correction gain Ko of the pressure-reducing electromagnetic valve 42 is a normally-closed electromagnetic valve, and has a structure in which the differential pressure across the valve acts in the valve opening direction. Therefore, when the control pressure PL increases, the pressure difference before and after the control pressure PL increases, and the valve is easily opened. Therefore, the gain is corrected so that the solenoid suction force acting in the valve opening direction is reduced.

(Second Embodiment) In the first embodiment, the brake control device for executing the by-wire control for generating the braking pressure based on the control corresponding to the driver performing the braking operation has been described. The present invention can be applied to a device having a master cylinder that mechanically generates a hydraulic pressure in accordance with an operation as long as the device controls a wheel cylinder pressure by an electromagnetic valve.

A brake control device according to a second embodiment shown in FIG. 7 is an example of the brake control device. In the drawing, reference numerals 1 and 2 denote a brake circuit, 3 denotes an out side gate valve, 3a denotes a one-way valve,
b is a relief valve, 4 is a pump, 4a is a suction circuit, 4b is a suction circuit, 4c is a discharge circuit, 4d is a check valve, 4p, 4p
Is a plunger, 4r is a pump chamber, 5 is an inflow valve, 6 is an outflow valve, 7 is a reservoir, 8 is a motor, 9 is an in-side gate valve,
Reference numeral 10 is a return passage, BP is a brake pedal, MC is a master cylinder, RES is a reservoir, and WC is a wheel cylinder.

In the second embodiment, when the driver operates the brake pedal BP, a hydraulic pressure is generated in the master cylinder MC, transmitted to the wheel cylinder WC via the brake circuits 1 and 2, and applied to the braking force. Occurs.

When executing the control for generating the braking force when the driver is not performing the braking operation, the in-side gate valve 9 is opened and the pump 4 is driven. By closing the valve 3 and controlling the opening and closing of the inflow valve 5 and the outflow valve 6, the wheel cylinder pressure can be controlled. In this case, the inflow valve 5
It is preferable to control the opening and closing of the outlet valve 6 and the outlet valve 6 by PWM control, and control signals output to these valves 5 and 6 are controlled based on the differential pressure.

Alternatively, the inflow valve 5 and the outflow valve 6 are not operated as shown in the figure, and in this state, the in-side gate valve 9 is opened and the pump 4 is operated. And the out side gate valve 3 is PWM
By controlling, the wheel cylinder pressure can be controlled.
That is, the pressure increase can be controlled based on the operation of the pump 4, and the pressure decrease can be controlled based on the opening of the out-side gate valve 3. Embodiment 1 in the control of the inflow valve 5, the outflow valve 6, and the out-side gate valve 3 which are the electromagnetic valves as described above.
Execute the correction described in.

Although the embodiment has been described with reference to the drawings, the present invention is not limited to the configuration of the above embodiment. In the embodiment, the hydraulic pressure control valve 40
The example in which the ABS unit 60 is provided in addition to the above is shown. This is to increase the responsiveness at the time of the ABS control. However, it is possible to perform the ABS control using the hydraulic pressure control valve 40. In this case, the ABS unit 60 is eliminated to simplify the configuration. Can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall view showing a brake control device according to a first embodiment.

FIG. 2 is a circuit diagram showing a regenerative current detection circuit according to the first embodiment.

FIG. 3 is a time chart showing a state of generation of a regenerative current according to the first embodiment.

FIG. 4 is an explanatory diagram of a regenerative current according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a portion for forming a control signal in the first embodiment.

FIG. 6 is a time chart showing a state of creating a correction gain in the first embodiment.

FIG. 7 is an overall view showing a brake control device according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 brake circuit 2 brake circuit 3 out side gate valve 3a one-way valve 3b relief valve 4 pump 4a suction circuit 4b suction circuit 4c discharge circuit 4d check valve 4p, 4p plunger 4r pump chamber 5 inflow valve 6 outflow valve 7 reservoir 8 motor 9 IN side gate valve 10 Return passage BP Brake pedal MC Master cylinder RES Reservoir WC Wheel cylinder 100 Accumulator 20 Main passage 21 Discharge valve 30 Suction circuit 31 Suction valve 40 Hydraulic pressure control valve 41 Pressure increasing solenoid valve 42 Pressure reducing solenoid valve 50 Drain circuit 60 ABS unit 61 Inflow valve 62 One-way valve 63 Outflow valve 64 Reservoir 70 Control unit 80 Sensor group 81 Brake sensor 82 Wheel speed sensor 83 Acceleration sensor 84 Throttle sensor 305 Solenoid coil 501 Regeneration Forming circuit 502 the current detection resistor 503 diode 504 Regenerative current detecting circuit BP brake pedal M motor P pump WC wheel cylinder

Claims (8)

[Claims] 1. A solenoid valve provided in the middle of a flow path through which a fluid flows and capable of switching between a fully closed state in which the flow path is blocked and a fully open state in which the flow path is communicated; Control means for performing width modulation control to adjust the opening degree, comprising: a differential pressure detecting means for detecting a differential pressure between upstream and downstream of the electromagnetic valve in the flow path, which is a differential pressure between upstream and downstream of the electromagnetic valve. Is provided, wherein the control means is configured to calculate a differential pressure correction gain based on the differential pressure before and after calculated by the differential pressure detection means, and to correct the output to the solenoid valve based on the differential pressure correction gain. A solenoid valve control device. 2. The electromagnetic valve according to claim 1, wherein the differential pressure correction gain corresponds to a fluid force in which a differential pressure acts on a valve body in a valve closing direction and a valve opening direction. Valve control device. 3. The control device according to claim 1, wherein the flow path is at least one of a supply flow path connecting a wheel cylinder and a hydraulic pressure source in a vehicle brake device, and a drain flow path connecting the wheel cylinder and a brake fluid recovery side. 3. The electromagnetic valve control device according to claim 1, wherein the means is configured to execute control of the electromagnetic valve so as to control the wheel cylinder pressure to a desired pressure based on an input relating to a traveling state. 4. A valve position estimating means for generating a regenerative current when the solenoid valve is energized and estimating a position of a valve body based on the regenerative current, wherein the differential pressure detecting means includes a valve. Wheel cylinder pressure estimating means for estimating the wheel cylinder pressure based on the position of the valve element estimated by the position estimating means is included, and the differential pressure between the estimated wheel cylinder pressure and the pressure of the hydraulic pressure source, the estimated wheel cylinder pressure and 4. The solenoid valve control device according to claim 3, wherein a pressure difference between the front and rear sides is estimated based on a pressure difference between the brake fluid and the brake fluid. 5. The electromagnetic valve is a normally-open pressure-increasing electromagnetic valve provided in the supply flow path, and the differential pressure detecting means includes a pressure of a hydraulic pressure source as PS, and an estimated wheel cylinder pressure as PL. Then, the differential pressure Pd_i before and after the pressure-intensifying solenoid valve is obtained by the calculation of Pd_i = PL-PS,
5. The solenoid valve control device according to claim 4, wherein the correction gain Ki for the pressure-intensifying solenoid valve is obtained by calculating Ki = αi × PS / Pd_i (where αi is a constant). 6. The solenoid valve is a normally-closed pressure-reducing solenoid valve provided in the drain passage, and the differential pressure detecting means is provided before and after the pressure-reducing solenoid valve when an estimated wheel cylinder pressure is set to PL. The differential pressure Pd_o is
= PLo and a correction gain Ko for the pressure-reducing solenoid valve is further calculated by the following formula: Ko = αo × PS / Pd_o (where αo is a constant). An electromagnetic valve control device as described in the above. 7. When the target pressure of the wheel cylinder is Pt, the control means sends a control signal PSIGi to the pressure-intensifying solenoid valve to PSIGi = βi × Ki × (Pt−PL) (where β
7. The electromagnetic valve control device according to claim 5, wherein i is a constant. 8. The control means, when the target pressure of the wheel cylinder is Pt, sends a control signal PSIGo for the pressure reducing solenoid valve to PSIGo = βo × Ko × (Pt−PL) (where β
The solenoid valve control device according to claim 6, wherein o is a constant.