JPH10138895A - Brake device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device for a vehicle which sets a braking distance as short as possible despite of a simple control in any circumstances in the brake controller which distributes the brake force of rear wheels to front wheels by a solenoid valve device. SOLUTION: Inlet valves 68a, 68b and outlet valves 70a, 70b are arranged in pipes connecting a tandem master cylinder 61 to respective rear wheels RR, RL respectively, and the inlet valves 68a, 68b and the outlet vales 70a, 70b are so set that, when a car body speed is a prescribed value or more and a car body deceleration is a prescribed value or more based on an EB control circuit 86 which receives outputs of respective sensors including wheel speed sensors provided to respective wheels, the inlet and outlet valves are quickly switched by difference between the maximum front wheel speed and the respective rear wheel speeds so as to hold, loosen, or reapply the brake, and the brake distribution of the front and the rear wheels is thus independently controlled so as to approximate to an ideal curve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle brake device.

[0002]

2. Description of the Related Art Conventionally, a so-called proportioning valve has been used for distributing braking force between a front wheel and a rear wheel so that a braking system for all wheels can be used equally. This is a configuration in which the output is mechanically depressurized with respect to the input, and is a valve that has been used for a long time. Recently, a method of electronically controlling the valve has been adopted. For example, according to the brake device described in DE 3728480 A1, as shown in FIG. 7, the master cylinder 1 has a 3-port 3-position solenoid valve 2 for both rear wheels, and a 3-port 3 valve for each front wheel. Position solenoid valves 3, 4 are connected, which are respectively connected to the wheel cylinders of both rear wheels 6a, 6b and the wheel cylinders of both front wheels 5a, 5b. Wheel speed sensors 7a, 7b, 7c are disposed on the respective wheels 5a, 5b, 6a, 6b. The sensors 7a, 7b detect the left and right speeds of the left and right front wheels 5a, 5b, respectively. The average speed of the rear wheels 6a, 6b is detected.

A two-port two-port valve is provided between the three-port three-position solenoid-operated directional control valve 2 for rear wheels and the wheel cylinders of both rear wheels 6a and 6b.
A position solenoid-operated directional control valve 10 is provided.
The distribution controller 9 is connected to a. When the brake pedal 1a is depressed, in the state shown in FIG.
a, 5b and both rear wheels 6a, 6b are subjected to a braking force. Upon receiving the output of the distribution controller 9, the electromagnetic switching valve 10 adds the illustrated communication position O and the cutoff position I to the solenoid portion 10a. The pulse output is switched alternately in accordance with the width and period of the pulse output, so that the relationship between the braking force on the front wheels 5a and 5b and the braking force on the rear wheels 6a and 6b can be approximated to an ideal curve. doing.
The control unit 8 includes a wheel speed sensor 7a,
In response to the outputs of 7b and 7c, anti-skid control is performed in a known manner. In response, the brake force of the front wheels 5a, 5b and the rear wheels 6a, 6b is maintained, reduced, and increased again.

However, in this conventional example, both rear wheels 6a, 6b
Are commonly controlled by an electromagnetic switching valve 10. When the vehicle is traveling on a curve while applying a brake, the inner wheel shows a tendency to lock, and if the switching valve 10 is controlled accordingly, the outer wheel side will have a braking force. Shortage. That is, the braking distance becomes longer. Also, the solenoid portion 10a of the electromagnetic switching valve 10
No disclosure is made as to how the pulse output applied to is formed.

FIG. 8 shows German Offenlegungsschrift DE 3440.
541A1 discloses a brake control device, in which a tandem master cylinder 21 with a hydro booster is connected to wheel cylinders of front wheels 22a and 22b and wheel cylinders of rear wheels 23a and 23b, respectively. 2 ports 2 common to wheels 23a and 23b
A position electromagnetic switching valve 24 is connected, which receives a pulse output of the control unit 25 by a solenoid portion 24a and applies a braking force to the rear wheels 23a and 23b to the front wheels 22.
The ideal braking force distribution is to be performed for the braking forces a and 22b. That is, although the electromagnetic switching valve 24 obtains an ideal curve by limiting the braking force in accordance with the width and cycle of the pulse output applied to the solenoid portion 24a, the electromagnetic switching valve 24 is commonly used for both the rear wheels 23a and 23b. Since one electromagnetic switching valve 24 is provided, it also has the same drawbacks as the first conventional example. Further, there is no description about the formation of a pulse output applied to the solenoid portion 24a of the electromagnetic switching valve 24.

According to the brake device described in Japanese Patent Application Laid-Open No. Hei 7-186921, as shown in FIG. 9, the master cylinder 31 has wheel cylinders for the front wheels 32a and 32b and wheel cylinders for the rear wheels 33a and 33b. Are connected to each other, and a brake pressure operating device 34a,
34b, 35a, and 35b are arranged, and they have the same configuration. Pistons are provided in the respective cylinders, and the pistons are driven left and right by motors 35a, 35b, and 36a, 36b to communicate with each wheel cylinder. The brake force applied to each wheel is controlled by increasing or decreasing the volume of the liquid chamber to be controlled. By controlling the motors 36a and 36b for the rear wheels 33a and 33b, the braking force distribution to the front wheels is made closer to an ideal curve. I have to. However, in such a configuration, the entire device becomes large, heavy, and the cost increases, similarly to a conventional mechanical pressure reducing valve (proportional valve).

FIG. 10 shows a brake device described in Japanese Patent Application Laid-Open No. 6-156249. In the figure, a tandem master cylinder 41 with a booster is provided with switching valves 9 and 10.
And the front wheel 42 via the anti-skid control valve device 44
a, 42b and rear wheels 43a, 43b
Wheel cylinders are connected. Further, between the tandem master cylinder 41 and the anti-skid control valve device 44, a first and a second traction slip control valve 45,
46 and first and second hydraulic pumps 47 and 48 are provided. The brake device also performs a drive slip control, and a hydraulic pressure generation including a hydraulic pump, a relief valve, a throttle and the like as a pressure source. A source 49 is provided. Known anti-skid control and drive slip control are performed by such a configuration, and the rear wheels 43a, 43b are controlled by selectively switching the first and second traction slip control valves 45 and 46 and controlling the pressure generation source 49. The braking force for the front wheel 43b is controlled so as to be close to an ideal curve with respect to the braking force for the front wheels 42a and 42b. Both rear wheels 43a, 43
The brakes b are controlled independently of each other, but the control for distributing the braking force uses the pressure generation source 49 for the drive slip control, so that the control is considered to be complicated.

FIG. 11 shows a brake device described in Japanese Patent Publication No. 4-502741. In the tandem master cylinder 51, a wheel cylinder of one of the wheels 54 is connected via an anti-skid control valve 52. It is connected to a wheel cylinder of the rear wheel 55 of the same system via a two-port two-position electromagnetic switching valve 53. A control device (distributor) 56 is connected to the solenoid 53a. Although the switching valve 53 takes two positions, it is a check valve in the shut-off position, but its valve opening pressure is sufficiently high. Upon receiving a pulse output from the distributor 56 to the solenoid unit 53a, hydraulic pressure is supplied to the wheel cylinder of the rear wheel 55 according to the frequency and width thereof,
The distribution of the braking force to the front wheels 54 is close to ideal.

In this conventional example, the X pipe is used, and the other pipes have the same pipe configuration. However, the other switching valve (not shown) is different from the switching valve 53 shown in the figure. It is not disclosed whether the relationship is controlled. Therefore, if the vehicle is driven in a curve if controlled in the same manner, the braking force on the outer wheel is insufficient as in the above-described prior art. In addition, in the claims, the solenoid valve generates the brake pressure at the rear wheels according to at least a nearly ideal braking force distribution at the rear wheels by a pulse width corresponding to the wheel slip of both wheels. It is controlled to make it smaller ... "
There is no further description in that embodiment, and it is not clear how the control pulse is formed specifically.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and in any case, the distribution of the braking force of the rear wheels to the front wheels is changed along an ideal curve, and the weight and size are reduced. It is another object of the present invention to provide a brake control device capable of reducing a braking distance under any condition with simple control.

[0011]

An object of the present invention is to provide an electromagnetic valve device in a pipe connecting a tandem master cylinder and a wheel cylinder of each rear wheel. When the vehicle deceleration and the vehicle speed exceed predetermined values, respectively, according to the control output of the electronic control device that receives the outputs of various sensors including the provided wheel speed sensors, the larger one of the wheel speeds of both front wheels and the rear wheel And when the difference is greater than a first predetermined value, the electromagnetic valve device is switched to maintain the brake fluid pressure, and when the difference is smaller than a second predetermined value, the brake is activated. A vehicle brake characterized in that the electromagnetic valve device is switched so as to increase the hydraulic pressure, and the braking force distribution between the front wheels and the rear wheels is independently controlled so as to approximate an ideal curve. Equipment, solved by That.

Another object of the present invention is to provide an electromagnetic valve device in a pipe connecting a tandem master cylinder and a wheel cylinder of each rear wheel, and the electromagnetic valve device is provided with a wheel speed provided for each wheel. When the vehicle deceleration and the vehicle speed exceed predetermined values, respectively, according to the control output of the electronic control device receiving the outputs of various sensors including the sensors, the difference between the larger one of the wheel speeds of both front wheels and the wheel speed of each rear wheel is obtained. A difference is detected, and when the difference becomes larger than a first predetermined value, the solenoid valve device is switched to maintain the brake fluid pressure, and when the difference becomes smaller than a second predetermined value, the brake fluid pressure is increased again. And switching the solenoid valve device to reduce the brake fluid pressure when the difference is greater than a third predetermined value that is greater than the first predetermined value. Ideal for braking force distribution with Brake system being characterized in that so as to independently control so as to approximate a line,
Solved by

In straight running, the electronic control unit receives outputs of wheel speed sensors and various other sensors, and ideally distributes a braking force in accordance with the motion state of the vehicle, the position of the center of gravity of the vehicle, and the movement of the center of gravity during braking. It can be changed along the curve, and the inside rear wheel is easy to lock when running on a curve,
By controlling the solenoid valve device independently of the front wheel side, the outer wheel increases the braking force as it is when traveling straight, while changing along the ideal curve, and the inner wheel side of the rear wheel prevents locking. Therefore, the braking force is reduced so that the outer wheel side of the rear wheel is controlled irrespective of the inner wheel side of the rear wheel, and the braking force is increased as it is, and the braking distance can be shortened. The above can be performed with simple control.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a brake device according to an embodiment of the present invention. In the figure, two hydraulic pressure generating chambers are defined in a cylinder body 63 of a tandem master cylinder 61 with a booster, and a brake pedal is provided. By stepping on 64, hydraulic pressure is generated in these via the booster section 62. These are transmitted to the wheel cylinders of the right rear wheel RR and the left front wheel FL via the inlet valves 68a and 69a through the conduits 65a and 65b. The power is transmitted to the wheel cylinders of the left rear wheel RL and the right front wheel FR via the inlet valves 68b and 69b. The wheel cylinders of these wheels are loosened through outlet valves 70a, 71a and 70b, 71b, respectively.
2a and 72b. This is a low pressure reservoir 7
3a and 73b. It has a known configuration,
A piston biased by a relatively weak spring is slidably fitted in the casing, and the brake fluid storage chamber is connected to the suction side of the hydraulic pump 74.

The hydraulic pump 74 is constructed in a known manner,
It comprises a motor 75, an eccentric mechanism 76, check valves 77a, 78b and 77a, 78b, and a pair of plungers reciprocate in opposite directions to check valves 77a, 77b.
b, the brake fluid is sucked from the reservoirs 73a and 73b, and the check valves 78a and 78b are opened.
It is configured to supply the pressurized liquid to the dampers 79a, 79b and the throttles 80a, 80b.

The wheels RR, FL, FR, RL are provided with wheel speed sensors 82a, 82b, 82c, 82d, which detect the rotation speed of these wheels when a vehicle equipped with this device is running. These detection signals are supplied to an ABS control circuit 85 and an EBD control circuit 86. The ABS control circuit 85 has a known configuration, evaluates the skid state of these wheels, and selectively excites the solenoids of the inlet valves 68a, 68b, 69a, 69b and the outlet valves 70a, 70b, 71a, 71b. I do.

In an ABS (anti-skid) control circuit 85, an approximate vehicle speed signal is generated as is well known, and this signal is compared with the wheel speed of each wheel to calculate the slip ratio of each wheel. In the embodiment, the approximate vehicle speed is formed as follows. That is, the brake pedal 4
After depressing, the wheel speed decreases and the vehicle speed also decreases.When the deceleration reaches a predetermined value for the first time, the wheel speed at that time is set as the initial value, and the gradient of the wheel speed at that time is linear. The vehicle speed is assumed to decrease, and, if the maximum wheel speed is higher than the approximate vehicle speed, the approximate vehicle speed is regarded as the approximate vehicle speed. A straight line or a curve T as shown in FIG. 2 is obtained. Note that the wheel speed V indicates the maximum change in the wheel speed among the four wheel speeds. However, in order to make the figure easier to understand, a specific wheel speed (a specific wheel has a maximum wheel speed within the illustrated time period). ) Are shown. A curve obtained by multiplying the approximate vehicle speed T by a predetermined slip ratio α or a straight line R for any of the wheels is set as a reference speed. When releasing the brake, the inlet valves 68a, 68b, 69a,
69b in the shut-off position, outlet valves 70a, 70
b, 71a, 71b are switched to the communication position and each wheel F
The brake pressure fluid is discharged from the L, FR, RL, and RR wheel cylinders to the reservoirs 73a and 73b. Also, when re-installing the brakes, the stairs must be included.
At this time, the inlet valves 68a, 68b, 69a,
69b is turned on / off at a predetermined timing.

According to the present invention, the EBD control circuit 86
The input terminals are also supplied with the detection outputs of the wheel speed sensors 82a, 82b, 82c, and 82d, and in addition to the G sensor, the yaw rate sensor,
A brake pedal depression signal and the like are supplied. In order to achieve this, the inlet valve 6 is set so as to approximate an ideal curve P indicating the braking force distribution between the rear wheels and the front wheels as shown in FIG.
8a, 68b and a signal for exciting the solenoids of the outlet valves 70a, 70b.

According to the embodiment of the present invention, these inlet valves 68a, 68b and outlet valve 7
The input lines a ₁ , a ₂ ,
EB controlled independently as shown as a ₃ and a ₄
Each signal is supplied from the output terminal group b of the EB control circuit 86. The inlet valves 68a, 68b
And the outlet valve 71a, the 71b is supplied via the output output from the terminals a even input line _{b 1, b 2, b 3} , b 4 of the above-described anti-skid control circuit 85. The outputs of the control circuits 85 and 86 selectively excite the solenoids of the rear wheel inlet valves 68a and 68b and the outlet valves 70a and 70b. An ABS control circuit 8 is provided for the inlet valves 69a, 69b and the outlet valves 71a, 71b for the front wheels.
Only the output of 5 is supplied via input lines b ₅ , b ₆ , b ₇ , b ₈ .

According to the embodiment of the present invention, until the deceleration of the vehicle reaches a predetermined value, the rear wheel braking force and the front wheel braking force are the same as shown in FIG. That is, as indicated by the point G, the braking force distribution control is performed when the vehicle body deceleration reaches a predetermined value and when the vehicle body speed exceeds the predetermined value, as indicated by a point G. In FIG. 3, straight lines g ₁ and g
_2, g _3, g ₄ shows each vehicle deceleration as parameters. In the EBD control circuit 86, G (not shown)
The detected force of the sensor is compared with the predetermined value. If the predetermined value is exceeded and the vehicle speed exceeds a predetermined value (the vehicle speed is
For example, if the speed is too low, such as 20 km / h or less, the braking force distribution control is not performed.) The distribution control of the braking force of the rear wheels to the front wheels is performed. A predetermined pulse pattern is selected in the EBD control circuit 86, and the solenoids of the inlet valves 68a, 68b and the outlet valves 70a, 70b are controlled in accordance with this pattern. The hydraulic pressure of the wheel cylinder is kept constant. Next, the solenoids of the inlet valves 68a, 68b are de-energized to re-raise, and the braking force of the rear wheel RR or RL increases again. If it is determined that the brake is overloaded compared to the rear wheel braking force on the ideal curve P, the inlet valves 68a, 68b
Is closed, the outlet valves 70a and 70b are opened, and the brake is released. Hereinafter, similarly, the solenoids of the inlet valves 68a, 68b and the outlet valves 70a, 70b are repeatedly excited and de-energized so as to approximate the ideal curve P, and the stepped rear wheel braking force as shown in FIG. Obtained and approximate to the ideal curve P. According to the present embodiment, since the right rear wheel RR and the left rear wheel RL are independently controlled, they are independently controlled so as to approach the ideal curve P. When the solenoid valves of the rear wheels are commonly controlled as in the past, locking is prevented for the inner rear wheel during curve running, but the braking force is insufficient for the outer rear wheel and the braking distance is reduced. However, in the present embodiment, such a situation is eliminated, locking is prevented for the inner rear wheel, and sufficient braking force is applied to the outer rear wheel to greatly increase the braking distance. Can be small. In the case of running on a curve, the braking force of the ideal curve P is set lower for the rear wheels on the inner wheel side than on the rear wheels on the outer wheel side.

The control of the brake fluid pressure for the front wheels of the rear wheels is performed according to a chart shown in FIG.

The time depresses the brake pedal 64 at t ₀ when the front wheel brake fluid pressure is changed as shown by the curve P _'r. In contrast, the brake fluid pressure of the rear wheel although indicate changes as shown by P _r, the front wheel speed V '(pick towards the wheel speed larger of the two front wheels. Hereinafter the same) time t
_{When the} brake fluid pressure is applied at ₀ , it changes as shown.
On the other hand, the wheel speed V of the rear wheel changes as shown, but according to the embodiment of the present invention, the difference between the wheel speed V 'of the front wheel and the wheel speed V of the rear wheel is always detected. and which, if this difference becomes X ₁ at time t _1, had the brake fluid pressure P _r of the rear wheels is increased similarly to the front-wheel brake fluid pressure P _'r meantime, the brake fluid pressure at the time t ₁ Is kept constant. Then, the wheel speed V of the rear wheel decreases, and this difference becomes X
The brake fluid pressure P _r of the rear wheel ₂ and made, above which not to increase the difference, under reduced pressure in a pulsed manner according to this embodiment. Although the wheel speed V of the rear wheel is come recovered with this, the difference is a constant again brake fluid pressure P _r becomes to X ₁ at time t _3, now if this difference is X ₃ and small the brake fluid pressure P _r of the rear wheels is increased in a pulse shape. Wheel speed V of the rear wheel is reduced again, the difference is again brake fluid pressure P _r becomes as X ₁ decreases with which the wheel speed V is constant. And is vacuum again the difference in pulses in order to small when fall to the wheel speed X _2. Wheel speed V is recovered, the difference is again raised becomes smaller again brake fluid pressure P _r and X _3. And the difference in time t ₈ to the X ₁ and comprising a certain brake fluid pressure. Hereinafter, time t
_9, t _10, t _11, rice pulse ......, brake holding, by the pulse-filling is repeated, controls the brake force distribution for the front wheels of the rear wheel is approximated to the ideal curve P shown in FIG. 3 can do.

FIG. 5 shows another embodiment of the present invention. Parts corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, according to the present embodiment, the H pipe is employed, and one pressure supply pipe 65a is connected to both front wheels FL, F.
R cylinder is connected to the other pressure supply pipe 6
5b is connected to the wheel cylinders of both rear wheels RL, RR. The ABS control circuit 85 and the EBD control circuit 86 are similarly configured, and the inlet valves 68a, 68b, which are electromagnetic control valve devices for both rear wheels RL, RR, are independently controlled.

The embodiments of the present invention are constructed and operated as described above. Of course, the present invention is not limited to these, and various modifications are possible based on the technical idea of the present invention. is there.

For example, in the above embodiment, the inlet valves 69a, 69b and the outlet valves 71a,
A conventional vehicle brake device that does not perform anti-skid control is also provided with a solenoid valve control device instead of using a mechanical pressure reducing proportional valve. The present invention is also applicable to the present invention.

In the above embodiment, the case where the braking force distribution control and the anti-skid control are performed has been described. However, the present invention is also applicable to a brake device that further performs drive slip control.

In the above embodiment, the EB control circuit 86 causes the solenoids of the inlet valves 68a, 68b and the outlet valves 70a, 70b for the rear wheels to maintain, decrease, and re-raise the braking force. Excitation was performed so as to approximate the ideal curve P of the brake distribution between the rear wheels and the front wheels. However, in some cases, the brake was not loosened, but simply added by holding and rising to approximate the ideal curve P. You may. In this case, the solenoid valve device is constituted only by the inlet valves 68a and 68b.

According to this modification, the brake fluid pressure Pr of the rear wheels can be changed with respect to the brake fluid pressure P'r of the front wheels in a time chart as shown in FIG. That 'but is going to decrease with the brake fluid pressure P'r, will the wheel speed V of the rear wheels is reduced contrast, the time t _1' front wheel speed V in the front wheel speed V ' When the difference between the wheel speed V and the rear wheel speed V reaches X ₁ ′, the brake fluid pressure is kept constant. When the wheel speed recovers and the difference decreases to X ₂ ′, the brake fluid pressure is increased for a predetermined time. This will decrease as the wheel speed V is shown because it is a short time increases sharply brake fluid pressure, the difference X at time t ₃ '
_When it becomes ₁ ', the braking force is increased again for a predetermined time and kept constant. Although the wheel speed V of the rear wheel is being changed as illustrated, the difference between the wheel speed V of the rear wheel 'again front wheel speed V in' the time t ₄ becomes small as X ₂ 'again a predetermined time Brake After increasing the fluid pressure, the brake fluid pressure is kept constant. Even by controlling the brake fluid pressure of the rear wheels, the distribution of the braking force of the rear wheels to the front wheels can be approximated to an ideal curve.

[0031]

As described above, according to the brake device of the present invention, the braking force can be almost ideally distributed to the front wheels by the simple control, and the braking device can be used in any traveling condition. A sufficient braking force can be applied to both rear wheels, and the braking distance can be reduced.

[Brief description of the drawings]

FIG. 1 is a piping diagram of a brake device according to a first embodiment of the present invention.

FIG. 2 is a chart showing a relationship between a wheel speed and a vehicle speed in an ABS control circuit in the piping system diagram.

FIG. 3 is a chart showing distribution of a front wheel braking force and a rear wheel braking force in the embodiment.

FIG. 4 is a time chart showing a control method according to the embodiment of the present invention.

FIG. 5 is a piping diagram of a brake device according to a second embodiment of the present invention.

FIG. 6 is a time chart illustrating a control method according to a modification.

FIG. 7 is a piping diagram of a brake device of a first conventional example.

FIG. 8 is a piping diagram of a brake device of a second conventional example.

FIG. 9 is a piping diagram of a brake device of a third conventional example.

FIG. 10 is a piping diagram of a brake device of a fourth conventional example.

FIG. 11 is a piping diagram of a brake device according to a fifth conventional example.

[Explanation of symbols]

 68a Inlet valve 68b Inlet valve 69a Inlet valve 69b Inlet valve 82a Wheel cylinder 82a Wheel cylinder 82a Wheel cylinder 82a Wheel cylinder 86 EBD control circuit

Claims (5)

[Claims] 1. A solenoid valve device is provided in a pipe connecting a tandem master cylinder and a wheel cylinder of each rear wheel, and the solenoid valve device includes various types including a wheel speed sensor provided on each wheel. When the vehicle deceleration and the vehicle speed exceed the predetermined values, the difference between the larger one of the front wheel speeds and the wheel speed of each rear wheel is detected by the control output of the electronic control device receiving the output of the sensor. When the difference is larger than a first predetermined value, the electromagnetic valve device is switched to maintain the brake fluid pressure, and when the difference is smaller than a second predetermined value, the brake fluid pressure is increased again. A vehicular brake device wherein the solenoid valve devices are switched to independently control the distribution of braking force between the front wheels and the rear wheels so as to approximate an ideal curve. 2. An electromagnetic valve device is disposed in a pipe connecting a tandem master cylinder and a wheel cylinder of each rear wheel. The electromagnetic valve device includes various types including a wheel speed sensor provided on each wheel. When the vehicle deceleration and the vehicle speed exceed the predetermined values, the difference between the larger one of the front wheel speeds and the wheel speed of each rear wheel is detected by the control output of the electronic control device receiving the output of the sensor. When the difference is larger than a first predetermined value, the electromagnetic valve device is switched to maintain the brake fluid pressure, and when the difference is smaller than a second predetermined value, the brake fluid pressure is increased again. When the difference is greater than a third predetermined value that is greater than the first predetermined value, the electromagnetic valve device is switched to reduce the brake fluid pressure, and the braking force between the front wheel and the rear wheel is changed. You can approximate the distribution to the ideal curve A vehicle brake device characterized in that it is controlled independently as described above. 3. The vehicle brake device according to claim 1, wherein the brake fluid pressure is increased in a pulsed manner. 4. The vehicle brake device according to claim 2, wherein the brake fluid pressure is increased again and the brake fluid pressure is decreased in a pulsed manner. 5. The vehicular brake device according to claim 1, wherein the electromagnetic valve device is also used for anti-skid control.