JPH07100435B2 - Hydraulic control device for anti-skidding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle that controls a brake fluid pressure transmitted to a wheel cylinder of a wheel brake device according to a rotating state or a skid state of a wheel of a vehicle or the like. TECHNICAL FIELD The present invention relates to a hydraulic pressure control device for an anti-skid device.

[Conventional technology]

As a device of this type, a hydraulic pressure for controlling the brake hydraulic pressure of the wheel cylinder in response to a command from a control unit that is arranged between the master cylinder and the wheel cylinder of the wheel brake device and evaluates the skid state of the wheels. A hydraulic control device for an anti-skid device having a control valve is known. For example, when the wheel is composed of a pair of front wheels and a pair of rear wheels, a hydraulic control valve is provided for each of the front and rear wheels, that is, four hydraulic control valves are provided,
There is no problem if the brake fluid pressures are controlled independently. Alternatively, for both rear wheels, there is no problem even if the brake hydraulic pressure is commonly controlled by one hydraulic pressure control valve according to the skid state of the rear wheel having the smaller rotational speed.

However, in the above case, since three or four hydraulic control valves are used, the entire apparatus (generally unitized with a reservoir or the like) is increased in size and weight. Further, the hydraulic control valve is expensive, which increases the cost.

Therefore, for example, it is conceivable to control the brake fluid pressures of both front wheels by two fluid pressure control valves in an X-type piping system and commonly control the brake fluid pressures of the respective rear wheels. . However, when the friction coefficient μ is greatly different on both sides of the road surface, there is a risk that the rear wheels on the opposite side (diagonal position) to the front wheels on the high μ side road surface may be locked. In this case, the directional stability of the vehicle is lost, which is very dangerous. It is also conceivable to control the brake fluid pressure by interposing a pressure reducing proportional control valve (proportioning valve) on the rear wheels, but the brake fluid pressure is proportional to the hydraulic pressure on the input side of this valve. As it rises, the fear of locking still persists.

In view of the above problems, the present applicant has two hydraulic control valves (two channels) to reduce the size and weight of the device while eliminating the risk of locking the rear wheels. For the purpose of providing a device, in the above-mentioned configuration, each of the front wheels is provided with the fluid pressure control valve, and when any one of these control valves starts control, the brake fluid pressure of the front wheel is lower. A hydraulic pressure control device for an anti-skid device, characterized in that the brake hydraulic pressure of at least the lower brake hydraulic pressure of the rear wheels on the same side as the front wheel is controlled according to the brake hydraulic pressure. Proposed. That is, pressure selecting means for outputting a pressure according to the lower one of the brake hydraulic pressures of both front wheels controlled by the hydraulic pressure control valve is provided between the wheel cylinders of both front wheels and the wheel cylinders of both rear wheels. Arranged. Further, the command from the control unit for controlling each hydraulic control valve is formed by evaluating the skid state of each front wheel.

However, in the above configuration, when braking strongly on a uniform road surface, it is assumed that the front and rear wheels are equipped with the same type of tires, and the braking force of the front and rear wheels is set so that the front wheels lock before the rear wheels. Although it is distributed appropriately, if the above prerequisites are not satisfied, for example, when using spiked tires only on the front wheels on the road surface on ice or snow, or when equipping a chain and the rear wheels are normal tires, On the contrary, the rear wheel can be locked before the front wheel. However, in the above configuration, the brake pressure is not controlled even if only the rear wheels tend to lock, so under such conditions, the control of the front wheels is started and the brake pressure may drop below the lock pressure of the rear wheels. Unless the rear wheels are unlocked, the directional stability of the vehicle cannot be maintained.

Even when the front and rear wheels are equipped with the same type of tire, when the friction coefficient of the brake lining decreases due to the so-called temperature fade phenomenon of the front wheel braking device and the lock pressure of the front wheels rises abnormally, especially on high μ road surfaces. At the time of strong braking, the brake pressure of the rear wheels is increased to a pressure proportional to the brake pressure of the front wheels by the pressure reducing proportional valve, and finally reaches the lock pressure or more, so that the rear wheels can lock before the front wheels. This causes the same problem as described above.

FIG. 7 is a graph showing such a problem. FIG. 7A shows a change in wheel speed when the brake is applied, FIG. 7B shows a command signal of the control unit, and FIG.
FIG. C shows changes in the brake fluid pressure of the wheels. That is, when the vehicle runs on a uniform road surface and the front and rear wheels are equipped with the same type of tire, when the brake pedal is depressed at time t ₀ , the brake fluid pressure P of the front wheels is as shown by the solid line in FIG. 7C. Rise and control the brake hold command at time t _1.
Units are generated. That is, among the valve drive signals EV and AV for the respective solenoids of the supply valve and the discharge valve that form the hydraulic control valve, AV is still "0" but EV is "1". As a result, the brake fluid pressure P on the front wheels is kept constant. Time t ₂
Then, the control unit issues a brake slack command. That is, the valve drive signal EV is still "1", but the valve drive signal AV changes from "0" to "1". As a result, the brake fluid pressure P on the front wheels decreases as shown in FIG. 7C. At time t ₃ , the valve drive signal AV becomes “0”, but EV is still “1”. This keeps the brake fluid pressure constant. Time valve drive signal EV at t ₄ becomes "0" (the control unit issues a brake re-filling command), the brake fluid pressure is increased again. When the valve drive signal EV becomes “1” again at time t ₅ , the brake fluid pressure is kept constant. Thereafter, similarly, the brake fluid pressure P rises in a stair-filled state, and at time t ₅ , the valve drive signal AV becomes "1" when the valve drive signal EV is "1". As a result, the brake fluid pressure P decreases. As described above, the brake fluid pressure P of the front wheels changes with time, but the brake fluid pressure P ′ of the rear wheels also decreases and changes according to the change of the brake fluid pressure P of the front wheels. Since the pressure reducing proportional valve is interposed, the brake fluid pressure P'of the rear wheels slightly lags the brake fluid pressure P of the front wheels due to the hysteresis phenomenon, but this delay is ignored in FIG. 7C. . In addition, the brake fluid pressure is affected by the hysteresis phenomenon of the pressure reducing proportional valve and the effect of the rigidity of the rear wheel brake device, that is, the wheel cylinder (a large amount of brake fluid is required to increase the brake fluid pressure by a certain amount in the low pressure range). The fluctuation range of P'is smaller than the fluctuation range of the brake fluid pressure P of the front wheels as shown in the figure.

Due to the change in the brake fluid pressure as described above, the wheel speeds V and V ′ of the front wheels and the rear wheels change as shown by the solid line in FIG. 7A and decrease without locking to perform desired anti-skid control. .

When the front wheel is equipped with a chain or the temperature fade phenomenon occurs, the lock pressure of the front wheel rises as described above, but in FIG. 7C, the brake fluid pressure P of the front wheel changes as shown by a broken line. That is, it fluctuates at a higher level than the solid line. On the other hand, the brake fluid pressure P'of the rear wheels exceeds the rear wheel lock limit pressure R as shown by the broken line, and even if the brake fluid pressure P of the front wheels is reduced thereafter, the fluctuation range may be smaller. It will never be unlocked. As shown by the broken line in FIG. 7A, the front wheels are not locked, but the rear wheels are locked. As a result, not only the anti-skid control is not properly performed, but also the directional stability is lost, which is extremely dangerous.

In view of the above problems, the applicant has two hydraulic pressure control valves (2
In order to provide a hydraulic pressure control device for an anti-skid device that can eliminate the risk of rear wheel locking in any case while making the device smaller and lighter as a channel) The unit comprises a first evaluation unit and a second evaluation unit, and the first evaluation unit evaluates the skid state of one of the front wheels and one of the rear wheels in the same piping system as the front wheel. Then, a command for controlling the first hydraulic pressure control valve by logically combining these evaluation results is issued, and the second evaluation unit controls the other of the front wheels and the rear wheel in the same piping system as the front wheel. The other skid state is evaluated, and the evaluation results are logically combined to issue a command to control the second hydraulic control valve. The device for liquid pressure control device previously proposed.

However, when the brakes are loosened according to the evaluation results of the rear wheels in the above configuration, all wheels are prevented from being locked, especially when the road surface is high μ, front wheels equipped with a chain or causing a temperature fade phenomenon. The brake fluid pressure of is decreased more than necessary, the braking distance is extended, and the feeling during braking is deteriorated. That is, both front wheels are equipped with spiked tires and chains, and when both rear wheels are normal tires, they are traveling on a high μ road surface, and the hydraulic control valve is controlled by a control signal indicating the evaluation result of the rear wheels. When the brakes are controlled to release the brakes, the front wheels that are also traveling on the high μ road surface will have a shortage of braking force (because they are equipped with spiked tires and chains, the lock pressure is very high), and that much braking distance. Extends. In addition, the brake fluid pressure on the front wheels is greatly reduced, the braking feeling is bad, and the feeling of deceleration is felt many times if the brakes are applied frequently, and the feeling is not good.

[Problems to be Solved by the Invention]

The present invention has been made in view of the above problems, and makes the braking distance shorter than the above-mentioned conventional example while eliminating the risk of locking the rear wheels even if the front wheels are equipped with a chain or the temperature fade phenomenon occurs. An object of the present invention is to provide a hydraulic pressure control device for an anti-skid device, which also improves the feeling during braking.

[Means for Solving the Problems]

According to the first aspect of the present invention, one of the pair of front wheels and the pair of rear wheels having the respective wheel cylinders connected by X pipes, one of the first hydraulic pressure generation chamber of the master cylinder and the front wheels. First hydraulic pressure control valve that is disposed between the front wheel wheel cylinder and the front wheel wheel cylinder and controls the brake hydraulic pressure of the front wheel wheel cylinder; the second hydraulic pressure generation chamber of the master cylinder and the other front wheel of the front wheels. Second hydraulic pressure control valve which is disposed between the front and rear wheel cylinders and controls the brake hydraulic pressure of the front wheel cylinder; evaluates the skid state of the wheel and controls the first and second hydraulic pressure control valves. A control unit for issuing a command, which is disposed between the wheel cylinders of the front wheels and the wheel cylinders of the rear wheels, and which controls the brake hydraulic pressure of the front wheels controlled by the first and second hydraulic pressure control valves. home The control unit evaluates the skid state of the front wheels and the rear wheels and outputs the pressure according to the other pressure. An anti-skid control device that issues a command for controlling a second hydraulic pressure control valve, the command including a brake holding command, a brake slackening command, and a brake stair step-in command for stepwise increasing the brake hydraulic pressure If the time from the start or the end of the command to the generation of the brake stairs command is less than a predetermined length, the first brake fluid pressure time in the brake stairs command is continued to the brake slack command. Achieved by a hydraulic control device for an anti-skid device, characterized in that it is made longer than usual depending on the length of time

Further, according to the second aspect of the present invention, one of the pair of front wheels and the pair of rear wheels having the respective wheel cylinders connected to each other by the X pipe, the first hydraulic pressure generating chamber of the master cylinder, and the front wheel. First hydraulic pressure control valve that is disposed between the front wheel wheel cylinder and the front wheel wheel cylinder and controls the brake hydraulic pressure of the front wheel wheel cylinder; the second hydraulic pressure generation chamber of the master cylinder and the other front wheel of the front wheels. Second hydraulic pressure control valve which is disposed between the front and rear wheel cylinders and controls the brake hydraulic pressure of the front wheel cylinder; evaluates the skid state of the wheel and controls the first and second hydraulic pressure control valves. A control unit for issuing a command, which is disposed between the wheel cylinders of the front wheels and the wheel cylinders of the rear wheels, and which controls the brake hydraulic pressure of the front wheels controlled by the first and second hydraulic pressure control valves. U The control unit evaluates the skid state of the front wheels and the rear wheels, and the first or the first or the second is based on a logical sum of control signals representing the evaluation results, the pressure selecting means outputting a pressure according to the lower pressure. An anti-skid control device that issues a command for controlling a second hydraulic pressure control valve, the command including a brake holding command, a brake slackening command, and a brake stair step-in command for stepwise increasing the brake hydraulic pressure If the time from the start or the end of the command until the acceleration of the front wheel or the rear wheel reaches a predetermined value is a predetermined length or less, the first brake fluid pressing time in the brake stair insertion is set to the brake slack. Achieved by a hydraulic control device for anti-skid device, which is longer than usual in accordance with the length of time of command It is.

Further, according to the third aspect of the present invention, the above-mentioned object is one of a pair of front wheels and a pair of rear wheels each of which has a wheel cylinder connected in an X pipe, a first hydraulic pressure generating chamber of the master cylinder, and the front wheel. First hydraulic pressure control valve that is disposed between the front wheel wheel cylinder and the front wheel wheel cylinder and controls the brake hydraulic pressure of the front wheel wheel cylinder; the second hydraulic pressure generation chamber of the master cylinder and the other front wheel of the front wheels. Second hydraulic pressure control valve which is disposed between the front and rear wheel cylinders and controls the brake hydraulic pressure of the front wheel cylinder; evaluates the skid state of the wheel and controls the first and second hydraulic pressure control valves. A control unit for issuing a command, which is disposed between the wheel cylinders of the front wheels and the wheel cylinders of the rear wheels, and which controls the brake hydraulic pressure of the front wheels controlled by the first and second hydraulic pressure control valves. U The control unit evaluates the skid state of the front wheels and the rear wheels, and the first or the first or the second is based on a logical sum of control signals representing the evaluation results, the pressure selecting means outputting a pressure according to the lower pressure. A command for controlling the second hydraulic pressure control valve is issued, and the command comprises a brake holding command, a brake slackening command, and a brake step-in command for stepwise increasing the brake hydraulic pressure, and the control signal representing the evaluation result is at least In a hydraulic control device for an anti-skid device including a deceleration signal indicating that a wheel deceleration is equal to or higher than a predetermined deceleration and an acceleration signal indicating that a wheel acceleration is equal to or higher than a predetermined acceleration, the deceleration signal disappears. If the time from when the acceleration signal is generated to the generation of the acceleration signal is less than a predetermined length, the first pressurization of the brake fluid in the brake stair insertion Time the brake loosen command antiskid device for hydraulic pressure control apparatus is characterized in that longer than the normal case in accordance with the length of the duration of, is accomplished by.

[Action]

Time to be measured, that is, the time from the start of the brake slack command, or the time from the end to the generation of the brake stair step-in command, the acceleration of the front wheel or the rear wheel from the start or the end of the brake slack command Is a high μ road surface or a low μ road surface depending on whether the time from the disappearance of the deceleration signal to the generation of the acceleration signal is below a predetermined length. When the road surface is high μ, the first brake fluid pressurization time of the staircase braking force is lengthened according to its friction coefficient to minimize the braking distance, the change in the braking force of the front wheels is reduced, and the number of brake operations is also reduced. It is possible to reduce the braking feeling and improve the braking feeling.

The following 12 cases will be described separately. That is, (A) when the logical sum of the control signals of the front wheels and the rear wheels on the same side is taken, (a) when the same type of tire is used for both the front and rear wheels, (1) the vehicle runs on a uniform low μ road surface. (2) When the vehicle is traveling on a uniform high μ road surface (3) When the vehicle is traveling on a split road surface (b) When the front wheels are equipped with spiked tires only (1) The vehicle is When traveling on a uniform low μ road surface (2) When traveling on a uniform high μ road surface (3) When traveling on a split road surface (B) With front wheels in a diagonal position When the logical sum of the control signals of the rear wheels is calculated, (a) when the same type of tire is used for both the front and rear wheels (1) when the vehicle is traveling on a uniform low μ road surface (2) when the vehicle has a uniform high When traveling on μ road surface (3) When vehicle is traveling on split road surface (b) Front wheels Only when equipped with spiked tires (1) When the vehicle is traveling on a uniform low μ road surface (2) When the vehicle is traveling on a uniform high μ road surface (3) The vehicle travels on a split road surface (A) When the control signals of the front wheels and the rear wheels on the same side of (A) are ORed, (a) When the same type of tires are installed on the front and rear wheels, (1) The vehicle is uniform When the vehicle is traveling on such a low μ road surface, when a control signal representing an evaluation result for relaxing the braking force is generated on either of the front wheels and the rear wheels, the control is performed by the first or second hydraulic pressure control valve. The brake fluid pressure of the front wheels for the fluid pressure control valve is reduced, and the brake fluid pressure of both rear wheels is reduced by the pressure selecting means. Therefore, locking of all wheels is prevented. At this time, for example, the time from the start of the brake force slackening command for slackening the brake force or from the end to the generation of the brake stair step-in command is equal to or longer than a predetermined length, so that the first brake fluid in the brake stair step-in The pressing time is usually relatively short.
Therefore, it is possible to prevent frequent locking and a tendency to lock thereafter.

Next, (A), (a) and (2) When the vehicle is traveling on a uniform high μ road surface, when a control signal for relaxing the braking force is generated on either of the front wheels and the rear wheels, As a result, the first or second hydraulic pressure control valve is controlled, and the brake hydraulic pressure of both rear wheels is reduced by the pressure selecting means. Therefore,
Locking of all wheels is prevented.

Also, at this time, shorten the control signal to relax the braking force,
That is, since the time from the start or end of the braking force relaxation command to the generation of the brake stairs loading command is less than the predetermined length, it is determined that the road surface on which the vehicle is traveling is a high μ road surface. However, since the first brake fluid pressing time in the brake staircase insertion becomes longer than usual in accordance with the length of the duration of the braking force slack command, the braking force is increased from a uniform low μ road surface,
The braking distance can be reduced.

Next, in (A), (a) and (3), that is, when the logical sum of the control signals indicating the evaluation results of the front wheels and the rear wheels on the same side is taken and the front and rear wheels are equipped with the same type of tire, Is traveling on a split road surface, when a control signal for relaxing the braking force is generated at the front wheels or rear wheels on the low μ side, the first or second hydraulic pressure control valve for the front wheels on the low μ side is generated. Is controlled, and the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means.

The same applies when a control signal for relaxing the braking force is generated on the front wheels or the rear wheels on the high μ side. Therefore, locking of all the wheels is prevented.

When the braking force slack control signal is generated on the front wheel on the high μ side, the generation time is relatively short, and the first brake fluid pressurization time during brake stair insertion is the same as the duration of the slack signal. Will be longer accordingly. Therefore, the braking force is increased, and the shortage of the braking force of the front wheels on the high μ side is avoided. Therefore, the braking distance is made smaller than in the conventional case, and the locking of all the wheels is prevented.

Next, in (A), (b) and (1), that is, when the logical sum of the control signals of the front wheel and the rear wheel on the same side is taken and only the front wheels are equipped with spiked tires or a fade phenomenon occurs,
(1) When the vehicle is traveling on a uniform low μ road surface, a control signal for relaxing the braking force is generated on one of the rear wheels, and the first or second liquid for the front wheel is diagonally positioned with this control signal. By controlling the pressure control valve, the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means. The same applies to the front wheel on the other side.

Also, since both rear wheels are traveling on a low μ road surface, the duration of the control signal for relaxing the braking force is relatively long, and the first brake fluid pressure injection time during brake stair insertion is relatively short in the normal case. Prevent frequent locking tendency.

Next, in the cases of (A), (b) and (2), the vehicle has a uniform high μ
When the vehicle is traveling on a road surface, a control signal for releasing the braking force is generated in one of the two rear wheels, which causes the first or second front wheel in a diagonal position with respect to the rear wheel.
The hydraulic pressure control valve is controlled, and the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means. The same applies when a control signal to relax the braking force is generated on the other rear wheel, but since both rear wheels are traveling on a high μ road surface, the time required to relax the braking force is relatively short and high. It is determined that the vehicle is traveling on a μ road surface, and the first brake fluid pressurization time when the brake stairs are stowed is set longer than usual according to the duration of the brake slack command, and the braking force is increased to increase the braking distance. Can be shorter.
Also, locking of all wheels is prevented.

Next, in the case of (A), (b) and (3), that is, when the vehicle is equipped with spiked tires only on the front wheels and is running on a split road surface, control that should relax the braking force to the rear wheels on the low μ side A signal is generated, which controls the first or second hydraulic pressure control valve for the front wheel in the diagonal position, and the braking force of both the rear wheels is reduced by the front wheel and the pressure selecting means. Since the front wheels on the low μ side are equipped with spiked tires, it is unlikely that they will tend to lock before the rear wheels on the same side, but if they do tend to lock, this front wheel The first or second hydraulic pressure control valve is controlled to reduce the braking force of both the front wheels and the rear wheels by the pressure selecting means. Therefore, locking of all the wheels is prevented.

Further, the pressure selecting means does not generate a control signal for relaxing the braking force on the rear wheel on the high μ side, but if it occurs, the road surface on which this wheel is traveling is on the high μ side. Therefore, it is possible to shorten the brake distance by lengthening the first brake fluid pressure time in the brake stair step-in command.

Next, (B) and (a), that is, the logical sum of the control signals for relaxing the braking force of the front and rear wheels in a diagonal positional relationship is calculated, and the same type of tire is used for both the front and rear wheels (1)
When the vehicle is driving on a uniform low μ road surface, when a control signal for relaxing the braking force is generated on one of the front wheels, this hydraulic control valve is controlled to select the braking force and pressure on this front wheel. The braking force of both rear wheels is reduced by the means. The same applies to the front wheel on the other side.

In addition, the length of the control signal that should release the braking force is relatively long, and it is determined that the vehicle is traveling on a low μ road surface. Prevents frequent locking.

Next, in the cases of (B), (a), and (2), the logical sum of the control signals for relaxing the braking force of the front and rear wheels at the diagonal position is calculated, and the same type of tire is mounted on the front and rear wheels. When driving on a uniform high μ road surface, when a control signal for relaxing the braking force is generated on either the front wheel or the rear wheel at a diagonal position, the first wheel for the front wheel of this system is generated.
Alternatively, the second hydraulic pressure control valve is controlled, and the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means. At this time, since the vehicle is traveling on a uniform high-μ road surface, the length of the control signal that should release the braking force is relatively short, and it is determined that the vehicle is traveling on a high-μ road surface. Depending on the length of the command duration, the first brake fluid pressing time in the brake stairs can be increased to increase the braking force, and thus the braking distance can be shortened.

Next, (B) (a) (3), that is, the logical sum of the control signals for relaxing the braking force of the front wheels and the rear wheels at the diagonal position is calculated, and the front and rear wheels are equipped with the same type of tires When traveling on a split road surface, when a control signal for relaxing the braking force is generated on either the front wheel or the rear wheel on the low μ side, the first or second hydraulic pressure control valve for this front wheel is generated. Is controlled, whereby the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means. Therefore, it is possible to prevent all the wheels from locking. Low μ
Since the first or second hydraulic pressure control valve is controlled by the brake slackening of the wheel traveling on the side road surface and the control signal, the first brake hydraulic pressure injection time in the brake stair insertion is a normal time and is relatively short. Therefore, it is possible to prevent the wheels from frequently locking.

Next, in the case of (B), (b) and (1), that is, the logical sum of the control signals for relaxing the braking force of the front and rear wheels at the diagonal position is calculated, and only the front wheels are equipped with spiked tires. Is driving on a uniform low μ road surface,
A control signal for releasing the braking force is generated on either of the two rear wheels, which controls the first or second hydraulic control valve for the front wheel, which is in a diagonal position with respect to the control signal. The braking force of both rear wheels is reduced by the selection means. The brake slackening time at this time is relatively short, and the initial setting time of the brake stairs may be normal, thus preventing frequent locking and locking of all wheels.

Next, in the case of (B), (b), and (2), that is, a vehicle in which spiked tires are provided only on the front wheels by taking the logical sum of the control signals to relax the braking force of the front and rear wheels in the diagonal position. When the vehicle is traveling on a uniform high μ road surface, a control signal for releasing the braking force is generated on either of the two rear wheels. As a result, the first or second hydraulic pressure control valve for the front wheels, which is in a diagonal position with respect to this, is controlled, and the braking force of both the rear wheels is reduced by this front wheel and the pressure selection means. At this time, since the vehicle is traveling on a uniform high-μ road surface, the braking force slack time is shorter than the set time as above, so it is determined that the vehicle is traveling on a high-μ road surface, and the first The brake fluid pressure time is lengthened according to the slack time, and the braking force is increased to reduce the braking distance. The same applies when a braking force slackening control signal is generated on the other rear wheel.

Next, in the case of (B), (b), and (3), that is, when the logical sum of the control signals for relaxing the braking force of the front wheels and the rear wheels at the diagonal position is taken and only the front wheels are equipped with spiked tires. When the vehicle is traveling on a split road surface, a control signal to relax the braking force is generated on the rear wheels traveling on the low μ side, which causes the front wheels at a diagonal position with this rear wheel. The first or second hydraulic pressure control valve for the vehicle is controlled, and the braking force of both the rear wheels is reduced by the front wheels and the pressure selecting means.

Also, because the braking force of the rear wheels running on the low μ side is relatively short, the initial brake fluid pressure time when the brake stairs are inserted is relatively short, preventing the wheels from locking frequently. ing. Of course, locking of all wheels is also prevented.

As described above, in the nine cases, the case in which the time from the start or end of the brake slackening designation to the brake stairway loading command is less than or equal to the predetermined length is described in the configuration of claim (1). However, of course, claim (2)
When the time from the start or the end of the brake slackening command, which is the configuration of the invention, until the acceleration of the front wheels or the rear wheels reaches a predetermined value is a predetermined length or less, the invention of claim (3) In the above case, the same can be said when the time from the disappearance of the deceleration signal to the generation of the acceleration signal is a predetermined length or less. In any of the inventions, locking of all wheels is prevented. Further, the braking distance can be made shorter than before while preventing frequent locking.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 6 show an embodiment of the present invention, in which the master cylinder (1) is connected to the pedal (2),
One of the hydraulic pressure generating chambers has a pipeline (3) and a hydraulic pressure control valve (4
a), connected to the wheel cylinder (7a) of the right front wheel (6a) via the conduit (5). The conduit (5) is connected to the first input port (9) of the valve device (8) which will be described in more detail below. The first output port (10), which normally communicates with the first input port (9) of the valve device (8), is the wheel cylinder of the left rear wheel (11b) via the pipe line (13) and the pressure reducing proportional valve (32b). Connected to (12b).

The other hydraulic pressure generating chamber of the master cylinder (1) is
6), the hydraulic control valve (4b), and the pipe (17), and is connected to the wheel cylinder (7b) of the left front wheel (6b). The line (17) is further connected to the second input port (18) of the valve device (8). Normally the second input port (18) of the valve device (8)
The second output port (14) communicating with is connected to the wheel cylinder (12a) of the right rear wheel (11a) via the pipe line (15).

The hydraulic pressure control valves (4a) (4b) are composed of supply valves (33a) (33b) and discharge valves (34a) (34b) as switching valves, respectively, and discharge ports of the discharge valves (34a) (34b) are connected to a conduit ( It is connected to the reservoirs (25a) (25b) via 60a) (60b). The reservoirs (25a) (25b) consist of pistons (27a) (27b) and weak springs (26a) (26b) slidably fitted to the main body,
This reservoir chamber is connected to the suction port of the hydraulic pump (20). As is well known, the hydraulic pump (20) includes a main body (21) that slidably accommodates a piston, an electric motor (22) that reciprocates the piston, and check valves (23a) (23b) (24a) (24b). The discharge port, that is, the check valve (23a) (23b) side is connected to the conduits (3) (16).

Wheel speed detectors (28a) (28b) (29a) (29b) are arranged on the wheels (6a) (6b) (11a) (11b), respectively. From these detectors, a pulse signal having a frequency proportional to the rotation speed of the wheels (6a) (6b) (11a) (11b) is obtained and applied to the control unit (31) as an input.

The control unit (31) is independent of the first evaluation circuit (35a), the first logic circuit (36a) connected to this output terminal, and the first evaluation circuit (35a) as surrounded by the one-dot chain line. A second evaluation circuit (35b) having the same circuit configuration, and a second logic circuit (36b) connected to this output terminal and having the same circuit configuration as the first logic circuit (36a).
b) and a motor drive circuit (37). Each of these circuits (35a) (35b) (36a) (36b) (37) will be described in detail later, but the input terminal of the first evaluation circuit (35a)
The output terminals of the wheel speed detectors (28a) (29b) are connected to a ₁ and a ₂ , respectively, and the input terminals of the second evaluation circuit (35b) are connected.
a ₁ ', a _2' respectively wheel speed detector in (28b) (29a)
Output terminal of is connected. That is, the first evaluation circuit (35
a) is the wheel speed signal of the right front wheel (6a) and the left rear wheel (11a).
b) receives the wheel speed signals, evaluates each of these,
Supplies the evaluation result to the first logic circuit (36a), by these logical sum as will be described later, respectively valve driving signal EV to the output terminal C _1, C _2, generates AV. Second evaluation circuit (35
b) is the wheel speed signal of the left front wheel (6b) and the right rear wheel (11b).
receives the wheel speed signals from a), evaluates each of these,
The evaluation result is supplied to the second logic circuit (36b), and the output terminals C ₁ ′ and C ₂ ′ are calculated by the logical sum of these as will be described later.
To generate a valve drive signal EV'AV '. These valve drive signals EV, AV, EV'AV 'are transmitted to the 2-position electromagnetic switching valve (33a) (3
4a), (33b) and (34b) solenoids Sa, Sa ', Sb, Sb'
Is supplied to. 2-position solenoid switching valve (33a) (34a), (33
b) (34b) takes one of two positions A, B or C, D depending on whether EV, AV, EV ', AV' to the solenoid is low "0" or high "1". Is configured. That is, when the valve drive signals EV and EV 'are "0", the switching valves (33a) (33b) serving as the supply valves are set to the position A, the both side passages are communicated, and EV and EV' are set to "1". Occasionally, it takes the position of B and blocks the passages on both sides. Valve drive signal AV,
When AV ′ is “0”, the switching valve (34a) (3
4b) takes the position of C and connects the master cylinder (1) side and the wheel cylinders (7a) (7b) side, but AV, A
When V'is "1", it takes the position of D, shuts off the master cylinder (1) side and the wheel cylinders (7a) (7b) side, and the wheel cylinder (7a) (7b) side and the reservoir (25
a) Connect with (25b) side. That is, when the control unit (31) issues a brake slack command, the valve drive signals EV, EV 'and AV, AV' are all "1", and when the brake constant hold command is issued, EV, EV 'are "1" and AV , AV ′
Is "0", and EV, EV 'and AV, AV' are all "0" when the brake command is given. The motor drive circuit (37) in the control unit (31) issues a brake slack command and thereafter continuously generates a motor drive signal Q during the anti-skid control, and the signal (Q) drives the motor (22). It

Next, the front wheel (6a) (6b) wheel cylinder (7a) (7b)
The details of the valve device (8) that receives the brake fluid pressure from the engine will be described with reference to FIG.

The body (61) of the valve device (8) has a stepped through hole (61
a) is formed, and the lid (6
2) is screwed with the seal ring (35) interposed, and the lid (36) is screwed with the seal ring (37) at the left end opening. The above-mentioned first input port (9) and second input port (18) are formed in the lids (62) and (36), respectively.

A piston (38) fitted with a seal ring (39) (40) is slidably fitted in the center of the stepped hole (61a), and a shaft-like portion (41a) integrally formed at both ends thereof. ) (41b) crosses the output chambers (50a) (50b) and is in contact with the valve balls (47a) (47b) in the normal state shown. Valve ball (47a) (47
b) is located in the input chamber (49a) (49b) and the spring (48a) (48b)
It is biased toward the valve seats (46a) (46b) by b). One valve seat (46b) is formed on the inner wall of the main body (61), while the other valve seat (46a) is formed on the valve seat member (45) press-fitted into the tubular member (44). . Cylindrical member (4
The above-mentioned output chamber (50a) is formed inside 4), and the first output port (1) is formed through the hole (44a) formed in this peripheral wall.
It is in communication with 0). The other output chamber (50b) directly communicates with the second output port (14).

The spring bearing rings (42a) (42b) are fitted in the shaft-like parts (41a) (41b) of the piston (38) in a loosely fitted state, and between them and the step part of the stepped hole (33). Springs (43a) (43b) are stretched and urge the spring bearing rings (42a) (42b) toward the center. In the normal state shown in the drawing, the flange portions of the spring receiving rings (42a) (42b) are the step portions (58) of the main body (61).
a) It is in contact with (58b). In this state, the piston (3
Only a small gap is formed between the main part (59) of 8) and the spring receiving rings (42a, 42b). This regulates the neutral position of the piston (38) in the stepped hole (33).

Switch (52) in the hole formed in the center of the body (32).
Is fitted and fitted with a seal ring (53), and its operator is fitted in a groove (51) formed on the outer circumference of the piston (38) at the neutral position. The lead wire (54) from the switch (52) is connected to the ten terminal of the battery (57) via the contact (55) of the b-contact relay and the alarm lamp (56).
That is, when the contact (55) is closed and the actuator of the switch (52) is activated, the alarm lamp (56) is turned on. The contact (55) of the b-contact relay is opened when the anti-skid device shown in FIG. 1 is activated and is normally closed. This is, for example, a relay that is excited by pressure when the hydraulic pump (20) is activated.

When the piston (38) is in the normal neutral position shown, the valve balls (47a) (47b) are separated from the valve seats (46a) (46b) by the shaft-shaped parts (41a) (41b). (49a) (4
9b) and the output chamber (50a) (50b) are connected. Further, in FIG. 1, the pipelines (3) and (5) and (16) and (1
The check valves (19a) and (19b) are connected to 7).
Although the forward direction is from the wheel cylinder side to the master cylinder side, the switching valves (33a) (33b) (34
Since a) and (34b) communicate with each other at the A and C positions via the throttle holes, the wheel cylinder (7a) ( 7b) (12a) (12b) is provided to circulate the pressure liquid to the master cylinder (1).

Since the first and second evaluation circuits (35a) and (35b) have the same structure, only one of the first evaluation circuits (35a) will be described with reference to FIG.

First, second evaluation circuit (35a) (35b) each front wheel evaluation circuit section (35a ₁₎ (35b ₁₎ and the rear wheel evaluation circuit section (35a ₂₎
(35b ₂ ), but these evaluation circuit sections are similarly constructed.

The signals from the wheel speed detectors (28a) (29b) are supplied to the wheel speed calculators (72a) (72b).
A digital or analog output proportional to the wheel speed is obtained from b), and the approximate vehicle speed generators (76a) (76b), the slip signal generators (77a) (77b), and the wheel acceleration / deceleration calculator or differentiator ( 73a) and (73b).

The approximate vehicle speed generators (76a) (76b) receive the outputs of the wheel speed calculators (72a) (72b) and generate outputs equal to the wheel speed until the wheel deceleration reaches a predetermined value. When the deceleration of is equal to or more than the predetermined value, the wheel speed at that time is set as an initial value, and thereafter, an approximate vehicle body speed that decreases at a predetermined gradient is generated. Approximate vehicle speed generator (76a) (7
The output of 6b) is supplied to the high output selector (71), and the higher output selected by this is the slip signal generator (77a) (7).
Wheel speed calculator (72a) (72b)
When the former vehicle speed is smaller than the latter by a predetermined amount or more, the slip ratio signal S is generated. This predetermined amount is set, for example, as a reference rate of 15%, and the percentage of the wheel speed to the approximate vehicle body speed is 100%.
The value (slip rate) subtracted from is compared with the reference rate, and if this slip rate is greater than the reference rate, the slip rate signal S
To occur.

Differentiators (73a) (73b) are wheel speed calculators (72a) (72b)
Is received and differentiated with respect to time, and the differentiated output is supplied to the deceleration signal generators (75a) (75b) and the acceleration signal generators (74a) (74b). The deceleration signal generator (75a) (75b) has a deceleration reference value (for example, -1.5g) set, and this is compared with the output of the differentiator (73a) (73b) to determine the differentiator (73a (73b), that is, when the wheel deceleration is greater than the deceleration reference value, the deceleration signal generators (75a) (75b) generate the deceleration signal -b. Further, an acceleration reference value (for example, 0.5 g) is set in the acceleration signal generators (74a) (74b), and this is compared with the output of the differentiator (73a) (73b), and the differentiator ( 73a) (7
When the output of 3b), that is, the acceleration of the wheel is larger than the acceleration reference value, the generators (74a) (74b) generate the acceleration signal +
b is generated.

The output terminals of the acceleration signal generators (74a) (74b) are the logical negation input terminals of the AND gates (92a) (92b) (shown with a circle. The same applies below) and the logical negation of the AND gates (90a) (90b). Input terminal, input terminal of AND gates (90a) (90b) via OFF delay timers (88a) (88b), first input terminal of OR gates (94a) (94b) and OR gate (96)
It is connected to the. The output terminals of the AND gates (90a) (90b) are connected to the input terminals of the pulse oscillators (78a) (78b) and the input terminals of the AND gates (93a) (93b), and the output terminals of the pulse oscillators (78a) (78b) are connected. Output terminal is AND gate (93
a) Connected to the logically negative input terminal of (93b). Acceleration signal generator (74a) (74b), Off delay timer (88a) (8
8b), pulse oscillator (78a) (78b), OR gate (94
a) (94b) and AND gates (90a) (90b) (93a) (9
3b) constitutes a brake rise signal generator (81a) (81b), which generates a pulse signal for slowly increasing the brake pressure. As will be described later, the brake pressure is slowly released during anti-skid control. The delay time of the off delay tumblers (88a) (88b) is set in consideration of the time to be raised. AND gate (93a) (93
The output terminal of b) is connected to the second input terminals of the above-mentioned OR gates (94a) (94b).

The output terminals of the deceleration signal generators (75a) (75b) are connected to the OR gates (94a) (94a) via the off delay timers (97a) (97b).
b) is connected to the third input terminal, and the output terminals of the slip signal generators (77a) (77b) are connected to the AND gate (92a).
a) (92b) is connected to the other input terminal, and the output terminals of the AND gates (92a) (92b) are connected to the above-mentioned OR gate (94a).
a) Connected to the fourth input terminal of (94b). Output terminal of OR gate (94a) (94b) and AND gate (92a) (9
Output + b of the control signal _{EV 1, EV 2, AV 1} , AV 2 and OR gate (96) at the output of 2b) is supplied to the first logic circuit in the subsequent stage (36a).

The output terminals of the AND gates (92a) (92b) are further connected to the off delay timers (95a) (95b), and this timer (95a)
The output terminal of (95b) is connected to the motor drive circuit (37). The delay time of the timer (95a) (95b) becomes "1" when the output of the AND gate (92a) (92b) becomes "1" first, and then becomes "1" during the anti-skid control even after it becomes "0". "Is set long enough to connect.

Since the first and second logic circuits (36a) and (36b) have the same structure, only the first logic circuit (36a) will be described with reference to FIG.

Control signal _{EV 1, AV 1, EV 2} , AV 2 of the first logic circuit (36a) as an output of the first evaluation circuit (35a), + b and receives a control signal EV ₁ one input of the OR gate (100) Supplied to the terminal. The control signal AV ₁ is supplied to one input terminal of the other OR gate (103). The control signal EV ₂ is AND gate (10
1) is supplied to one input terminal, and the output signal AV ₁ Z from the first evaluation circuit (35a) is supplied to the other input terminal via the knot gate (102). The control signal AV ₂ is supplied to the other input terminal of the OR gate (103). The output terminals of the OR gates (100) (103) are connected to the amplifier (10
7) It is connected to the solenoid Sa of the supply valve (33a) and the solenoid Sa 'of the discharge valve (34a) in FIG. 1 via (108). That is, the valve drive signals EV and AV amplified by the amplifiers (107) and (108) are supplied to the solenoids Sa and Sa '.

The output of the OR gate (103) is further supplied to the first timer (109) and the second timer (110). Second timer (1
The + b signal is supplied to 10). That is, the output terminal of the OR gate (96) of the evaluation circuit (35a) at the previous stage is connected. The first timer (109) starts its operation when the output of the OR gate (103) rises, and stops its operation when it falls. That is, the duration T ₀ of the output of the OR gate (103) is measured. The second timer (110) starts operating when the output of the OR gate (103) rises,
The operation stops when the + b signal falls. That is, after the brake is relaxed by the valve drive signal AV for T ₀ time, the braking force is kept constant, the wheel speed is recovered, the + b signal is generated, and the time T until it disappears is measured. This measurement time T is supplied to the comparator (111). Here, it is compared with the predetermined time TR, and when it is smaller than this, the comparator (11
The output of 1) is "1", and when it is large, it is "0".
Generally, when traveling on a road surface with a high friction coefficient (high μ road surface), the wheel speed recovers quickly, so in consideration of this, the predetermined time TR is set so that it can be distinguished whether the road surface is high μ road surface or low μ road surface. It is set. Therefore, the output of the comparator (111) is "1".
When, the vehicle is running on a high μ road surface.

The output of the comparator (111) is supplied to the gate circuit (112),
When this output is "1", the output of the first timer (109) is supplied to the oscillation start adjusting circuit (113). The output R of the oscillation start adjusting circuit (113) is the evaluation circuit (35
The oscillator (78a) is supplied to the oscillator (78a) (78b) of (a), and is generated according to the output of the first timer (109), that is, the time T _0.
It works by delaying the start of oscillation of (78b). This start delay time T ₂ is, for example, 1/3 or 1/4 of the time T ₀ .

FIG. 5 shows the motor drive circuit (37), which includes an OR gate (11
4) and an amplifier (115). OR gate (11
AV from the first evaluation circuit (35a) is connected to the first input terminal of 4).
_{The 2} Z signal is supplied, and the AV ₁ Z signal is supplied to the second input terminal. The AV ₁ Z signal is formed by the skid state of the right front wheel (6a), and the AV ₂ Z signal is formed by the skid state of the left rear wheel (11b).
Similarly, in b), the AV ₁ Z'signal is formed by the skid state of the left front wheel (6b) and the AV ₂ Z'signal is formed by the skid state of the right rear wheel (11a), which are respectively the fourth signals of the OR gate (114). , And the third input terminal. Second,
The fourth input terminals are respectively connected to the first and second logic circuits (36a) (3
6b) connected to one logic circuit (36a)
As shown, it is connected to the AND gate (101) via the NOT gate (102) in the logic circuit (36a). The output of the OR gate (109) is amplified by the amplifier (115) and becomes a Q signal, which is a signal for driving the motor (22) in FIG.

Similarly, in the second evaluation circuit (35b), the control signals EV ₁ , EV ₂ , AV ₁ , AV ₂ , + b in the first evaluation circuit (35a) are also used.
Corresponding to the control signals EV ₁ ′, EV ₂ ′, AV ₁ ′, AV ₂ ′, + b
Which are combined in the second logic circuit (36b) and output signals EV ', AV', corresponding to the valve drive signals EV, AV, R as output signals in the first logic circuit (36a).
R'is formed, and these are respectively the solenoid Sb of the supply valve (33b), the solenoid Sb 'of the discharge valve (34b) and the second.
It is supplied to the oscillator of the evaluation circuit (35b).

The embodiment of the present invention is configured as described above. Next, this operation will be described.

It is now assumed that the brake pedal (2) is depressed to apply a sudden brake. In addition, the wheels (6a) (6b) (11a) (11
In b), it is assumed that the tires of the same type are equipped and the vehicle is traveling on a road surface with a uniform friction coefficient. At the beginning of braking, the valve drive signals EV, A from the control unit (31)
Since V, EV 'and AV' are all "0", the switching valve (33
a) (34a), (33b) and (34b) are located at positions A and C, respectively. Therefore, the pressure liquid from the master cylinder (1) is supplied to the pipe lines (3) (16), the switching valves (33a) (34a), (33b) (34b).
It is supplied to the wheel cylinders (7a) (7b) of the front wheels (6a) (6b) through the pipes (5) (17). This pressure liquid is further applied to the first input port (9), the second input port (18), the input chambers (49a) (49b), the output chambers (50a) (5) of the valve device (8).
0b), the first output port (10), the second output port (14),
It is also supplied to the wheel cylinders (12a) (12b) of the rear wheels (11a) (11b) through the pipes (13) (15) and the pressure reducing valves (32a) (32b). As a result, the wheels (6a) (6b) (11a) (1
The brake is applied to 1b). The pressure reducing valves (32a) (32b) perform known operations, and when the pressure on the input side is below a predetermined value,
Although it is transmitted to the output side as it is, when it is equal to or higher than a predetermined value, the pressure is reduced at a substantially constant rate and transmitted to the output side.

Wheels (6a) (6b) (11a) (1
1b) reaches a predetermined deceleration (in this case, the decelerations are made at the same time in order to make the explanation easier to understand. The same applies to the slip ratio below), that is, the deceleration by the evaluation circuits (35a) (35b). signal generator (75a) (75b) (typically marks Shimesuru the first evaluation circuit (35a).) When generating a deceleration signal _{-b EV 1 EV 2, EV 1} ', EV 2' signal ' The output EV and EV 'of the logic circuits (36a) and (36b) become "1". Therefore, the switching valves (33a) (33b) are switched to the B position, and the master cylinder (1) side and the wheel cylinders (7a) (7b) side are shut off. As a result, the brake fluid pressure in the wheel cylinders (7a) (7b) (12a) (12b) is kept constant.

When the wheel deceleration becomes smaller than a predetermined value, the deceleration signal −
Although b disappears, the input to the OR gates (94a) (94b) is still held at "1" by the off delay timers (97a) (97b). After this, when the wheel reaches the predetermined slip ratio,
Alternatively, when the slip ratio is reached while the deceleration signal is being generated, the slip signal generators (77a) and (77b) generate the slip signal S in FIG. Acceleration signal generator (74a) (74
b) has not generated the acceleration signal + b yet, the control signals AV ₁ , AV ₂ , and AV ₂ are output as the outputs of the AND gates (92a) (92b).
AV ₁ ′ and AV ₂ ′ also become “1”, and the valve drive signals AV and AV ′ as the outputs of the logic circuits (36a) and (36b) become “1” together with EV and EV ′.
Becomes As a result, the switching valves (33a) (33b), (34a) (3
4b) switches to positions B and D. Pipelines (3) and (5)
Although (16) and (17) are cut off, the pipelines (5) and (60a) and (17) and (60b) are communicated with each other.

The brake fluid in the wheel cylinders (7a) (7b) of the front wheels (6a) (6b) flows into the reservoirs (25a) (25b) through the pipelines (5) (60a), (17) (60b). In addition, the rear wheels (11
The brake fluid in the wheel cylinders (12a) and (12b) of a) and (11b) is also pipe lines (15) and (13), the output ports (14) and (10) of the valve device (8), and the output chambers (50a) and (50b). , Input room (49a)
(49b), input port (18) (9), pipeline (17)
(5), (60b) (60a) through the reservoir (25a) (25
b) flows in. This releases the brakes on the front wheels (6a) (6b) and the rear wheels (10a) (10b).

The hydraulic pump (20) starts driving when the control signals AV ₁ , AV ₂ , AV ₁ ′, AV ₂ ′ become “1”, and the reservoirs (25a) (25b)
Since it is sent to the pipe lines (3) and (16) with an almost equal intake amount, the hydraulic pressure on both sides of the piston (38) in the valve device (8) decreases at about the same speed. Therefore piston (38)
Does not move from the neutral position and moves the valve balls (47a) (47b) into the valve seat (46
It has been separated from a) and (46b).

When the wheel speed recovers and reaches a predetermined acceleration, acceleration signal + b is generated from the acceleration signal generators (74a) (74b).
As a result, the control signals EV ₁ , EV ₂ , EV ₁ ′, EV ₂ ′ as the outputs of the evaluation circuits (35a) (35b) become “1”, and the valve drive signals as the outputs of the logic circuits (36a) (36b). EV and EV 'are "1". The brake fluid pressure on the wheels is kept in a pair.

When the acceleration signal + b disappears, the pulse oscillator (78a) (78
b) is activated and outputs EV ₁ , EV ₂ , EV ₁ ′, EV ₂ ′ are “1”, “0”, for the delay time of the OFF delay timer (88a) (88b).
It changes in a pulse shape such as “1”, “0” .... As a result, the outputs EV and EV 'of the logic circuits (36a) and (36b) also change, and the brake fluid pressure on the wheels is increased stepwise. In this case, it is assumed that the vehicle is traveling on a high μ road surface. Therefore, the time T is shorter than the time TR, but the logic circuit (36
The action of a) and (36b) will be described later.

Hereinafter, similar control is repeated, and when the vehicle reaches a desired speed or stops, the depression on the brake pedal (2) is released. Wheel cylinder (7
Brake fluid from a) (7b) (12a) (12b) is provided in each pipeline, valve device (8), switching valve (4a) (4b), check valve (19a) (19).
Return to the master cylinder (1) through b). Therefore, the brake is released.

In the above description of action, EV ₁ , EV ₂ , EV ₁ ′, EV ₂ ′ or AV 1
₁ , AV ₂ , AV ₁ ′, AV ₂ ′ are assumed to be “0” or “1” at the same time, but the friction coefficient of the road surface on which the wheels (6a) (6b), (11a) (11b) travel is A case where the left and right are greatly different, for example, a case where the road surface on the wheels (6a) (11a) side has a relatively small friction coefficient (so-called split road surface) will be described below.

The right wheel (6a) (11
The deceleration signal -b or the slip signal S of a) shall be generated at the same time. That is, since the control signals EV ₁ and EV ₂ ′ and AV ₁ and AV ₂ ′ as the outputs of the evaluation circuits (35a) and (35b) simultaneously become “0” and “1”, the logic circuits (36a) (36b). ), The valve drive signals EV, EV 'or AV, AV' also become "0" and "1" at the same time, and the switching valves (33a) (33b) (34a) (34a)
b) can be switched at the same time. Therefore, the brake fluid pressures of all the wheels are kept constant, decreased or increased at the same time, and any locking of the wheels can be prevented. At this time, the piston (38) in the valve device (8) remains stopped at the neutral position. The time T is greater than the time TR.

Although the above description has been made assuming that all wheels are equipped with the same type of tires, the case where only the front wheels (6a) and (6b) are equipped with spiked tires or chains will be described next. First, the case where the vehicle is traveling on a uniform high μ road surface will be described. The rear wheel (11a) is used for clarity.
The skid condition in (11b) shall change equally.
When the brakes are applied at time t ₀ , the brake fluid pressures P and P'of the front wheels and the rear wheels rise as shown in FIG. 6B. By the pressure reducing valves (32a) and (32b), the brake fluid pressure P'of the rear wheels is reduced compared to the brake fluid pressure P of the front wheels and rises above a predetermined pressure. At time t ₁ , the first and second evaluation circuits (35a) (3
The outputs EV ₂ and EV ₂ ′ of 5b) become “1” as shown in FIG. 6C. That is, the deceleration signal -b of the rear wheels (11a) (11b) is generated. Output E of the first and second logic circuits (36a) (36b)
V and EV 'become "1", and the brake fluid pressures P and P'are held constant.

After disappearance of the deceleration signal -b, or slip signal S of the rear wheels (11a) (11b) is generated in the time t ₂ during the generation. First,
The outputs AV ₂ and AV ₂ ′ of the second evaluation circuits (35a) and (35b) become "1". As a result, the brake fluid pressures P and P'decrease.

At time t ₃ , the slip signal S disappears and the outputs AV ₂ and AV ₂ ′ become “0”. Deceleration signal -b is also off delay timer disappeared (97a) (97b) EV output for the delay time of _2, EV ₂ '
Is still "1" and the brake fluid pressures P and P'are kept constant. At time t ₄ , the acceleration signal + b of the rear wheels (11a) (11b) is generated. Output even if the output of the OFF delay timer (97a) (97b) becomes "0" while this signal + b is generated.
EV ₂ and EV ₂ ′ are still “1”.

At time t ₅ , the + b signal disappears. Due to this
Although the oscillators (78a) and (78b) are started to be driven after T ₁ in FIG. 3, the driving is further started after time T _{2 in} the present embodiment.

That is, the time T between the times t _{2 and} t ₅ is the second timer (11
0) and the output of the comparator (111) becomes "1" because it is less than the predetermined time TR, and the measured value T _{0 of} the first timer (109) oscillates via the gate circuit (112). It is supplied to the start adjustment circuit (113). The output R corresponding to the measured value T ₀ is supplied to the oscillators (78a) (78b). This delays the start of oscillation by time T ₂ .

Therefore, during the time (T ₁ + T ₂ ), the brake fluid pressures P and P ′ are increased. After this, stairs are packed as in the conventional case. In FIG. 6B, the dotted line shows the stepwise filling of the brake fluid pressure of the conventional front wheels, but the braking force corresponding to the area of the hatched portion between this and the solid line is compensated by this embodiment, and that much. The braking distance can be reduced. As shown in FIG. 6B, although the front wheels do not show the lock tendency, when the brake fluid pressure P ′ of the rear wheels is decreased by ΔPr to release the lock tendency of the rear wheels, the pressure reducing valve (32a) The brake fluid pressure P on the input side of (32b), that is, on the front wheels, drops significantly as ΔPf. For this reason, the conventional change in the brake fluid pressure P causes the driver to feel uncomfortable during the control, but in this embodiment, the stairs as described above immediately afterward can significantly reduce the discomfort. it can. That is, the excessive looseness of the brakes of the front wheels is compensated for when the stairs are first set, so that the control distance is reduced and the driving feeling is improved.

Next, a case where both front wheels are equipped with spiked tires or chains (or when a fade phenomenon is shown) and traveling on a split road surface will be described. Right front wheel (6
a) Rear wheel (11a) is on the low μ side Left front wheel (6b) Rear wheel (11b)
Is on the high μ side, the output E of the second evaluation circuit (35b)
V ₂ ′ and AV ₂ ′ occur preferentially, and front wheels (6b) and rear wheels (1
The brake fluid pressures P and P'of 1a) are held and kept constant. Next, when the stairs are put in, the brake fluid pressure P,
The valve device (8) shown in FIG.
At, a differential pressure is generated on both sides of the piston (38).

In FIG. 2, the input chamber (49 on the left side of the piston (38) is
Since the hydraulic pressures in b) and the output chamber (50b) are lower than those on the right side, the piston (38) moves to the left. As a result, the right valve chamber (47a) is seated on the valve seat (46a) by the spring force of the spring (48a). On the other hand, the valve ball (47b) on the left side is pushed by the shaft-like portion (41b) in a direction further away from the valve seat (46b). Input chamber (49b) and output chamber (5) on the left side of the piston (38)
0) is still in communication, but the right input chamber (49a) and output chamber (50a) are cut off. That is, the liquid supply from the master cylinder (1) to the wheel cylinder (12b) of one rear wheel (11b) is shut off.

When the piston (38) moves further to the left with the pressure drop in the left input chamber (49b) and output chamber (50b) in the blocked state as described above, the blocked output chamber on the right side of the piston (3) The volume of (50a) increases. That is, this output chamber (5
The hydraulic pressure in the wheel cylinder (12b) of the rear wheel (11b), which is in communication with 0a) via the output port (10) and the conduit (13), decreases. As long as the right valve ball (47a) is seated on the valve seat (46a), the piston (38) moves to the right when the hydraulic pressure in the left input chamber (49b) and output chamber (50b) rises again. And the volume of the right output chamber (50a) decreases. As a result, the brake fluid pressure in the wheel cylinder (12b) of the rear wheel (11b) rises again. That is, the rear wheel (11b) is
It will be controlled according to the brake fluid pressure in b). Therefore, the rear wheel (11b) on the higher friction coefficient side of the road surface is also prevented from being locked, like the other rear wheel (11a).

Next, a case where a failure occurs in either one of the systems will be described.

For example, if liquid leakage occurs in the system on the side of the pipe (3), even if the brake pedal (2) is depressed, the wheel cylinder (7
The hydraulic pressure of a) and (12b) does not rise. On the other hand, the piston (38) moves to the right in the valve device (8) due to the pressure increase in the system on the side of the pipeline (16). Since the anti-skid control is not performed, the contact (55) remains closed, and the switch (52) is closed by the movement of the piston (38), so current flows from the battery (57) and the alarm lamp (56) lights up. To do. This allows the driver to recognize that the device is failing. If the contact has not failed, the contact (55) opens with anti-skid control (for example, driving of the hydraulic pump (20) starts), so the piston (38)
The alarm lamp (56) does not light up when is moved.

Although the embodiments of the present invention have been described above, needless to say, the present invention is not limited to these, and various modifications can be made based on the technical idea of the present invention.

For example, as the evaluation circuit, the one shown in FIG. 2 is given, but various known control units can be applied.

In addition, depending on the logic configuration, each one three-position electromagnetic switching valve may be used as the hydraulic pressure control valve (4a) (4b).

In the above embodiments, the approximate vehicle speed generator (76a) (76
Although the larger one of the outputs of b) is taken, the one having the larger wheel speed may be selected to form the approximate vehicle body speed.

In the above embodiment, the second timer (110) measures the time T from the start of the brake slackening to the end of the constant holding and compares this with the predetermined time T _R. However, instead of this, It is also possible to measure the time from the end of brake slackening (time t ₃ ) to the end of constant holding, and compare this with a predetermined time. Alternatively, the time from the disappearance of the deceleration signal −b until the generation of the acceleration signal + b is measured,
This may be compared with a predetermined time. In any case, the predetermined time to be compared is determined so that it can be discriminated whether the road is on the high μ road surface or the low μ road surface.

Further, in the above embodiment, the first loading time of stairs loading is + b
The time from the disappearance of the signal to the start of the oscillator drive was used, but instead of this, the first pulse output of the oscillator
The duty factor (O level time) may be changed.

Further, in the above embodiment, the logical sum of the control signals representing the evaluation results of the skid states of the front wheels and the rear wheels of the same piping system is taken, but instead of this, the evaluation of the skid states of the front wheels and the rear wheels on the same side is performed. The results may be logically combined.

〔The invention's effect〕

As described above, according to the hydraulic control device for an anti-skid device of the present invention, since only two hydraulic control valves (two channels) are used, the device is smaller and lighter than the three-channel and four-channel type. While reducing the cost and reducing the cost, the front wheel may fade, and even if a chain is equipped, the braking distance can be made as short as possible to reliably prevent the rear wheel from locking and maintain the steering stability. . Also, the driving sensation during control should be good.

[Brief description of drawings]

FIG. 1 is a diagram showing a piping system and electric wiring of a hydraulic pressure adjusting device for an anti-skid control device according to an embodiment of the present invention, and FIG.
The drawing is an enlarged cross-sectional view of the valve device in FIG. 1, and FIG.
FIG. 4 is a block diagram of a first evaluation circuit, FIG. 4 is a block diagram of a first logic circuit in FIG. 1, FIG. 5 is a block diagram of a motor drive circuit in FIG. 1, and FIG. 6 is an operation of this embodiment. And FIG. 7 are graphs for explaining the operation of the conventional hydraulic pressure adjusting device for an anti-skid device. In the figure, (4a) (4b) ... hydraulic control valve (6a) (6b) (11a) (11b) ... wheel (8) ... valve device (31) ... control unit (35a) ( 35b) …… Evaluation circuit (36a) (36b) …… Logic circuit

Claims (3)

[Claims] 1. A pair of front wheels and a pair of rear wheels each having a wheel cylinder connected to each other in an X pipe arrangement, between a first hydraulic pressure generation chamber of a master cylinder and a wheel cylinder of one of the front wheels. A first hydraulic pressure control valve provided to control the brake hydraulic pressure of the wheel cylinder of the front wheel; disposed between the second hydraulic pressure generation chamber of the master cylinder and the wheel cylinder of the other front wheel of the front wheels A second hydraulic control valve for controlling the brake hydraulic pressure of the wheel cylinder of the front wheel; a control unit for evaluating the skid state of the wheel and issuing a command for controlling the first and second hydraulic control valves; both front wheels Of the brake fluid pressure of the front wheels controlled by the first and second hydraulic pressure control valves, which is disposed between the wheel cylinder of the front wheel and the wheel cylinders of the rear wheels. Out The control unit evaluates the skid states of the front wheels and the rear wheels, and controls the first or second hydraulic control valve by the logical sum of the control signals representing the evaluation results. In the anti-skid control device consisting of a brake holding command, a brake slackening command, and a brake stair step-in command for stepwise increasing the brake fluid pressure, from the start of the brake slackening command or from the end of the command. When the time until the brake stairs loading command is generated is a predetermined length or less, the first brake fluid pressing time in the brake stairs loading is a normal case according to the length of the duration of the brake slacking command. Hydraulic control device for anti-skid device characterized by being made longer. 2. A pair of front wheels and a pair of rear wheels, each wheel cylinder connected to each other by X pipes, between the first hydraulic pressure generating chamber of the master cylinder and one of the front wheels. A first hydraulic pressure control valve provided to control the brake hydraulic pressure of the wheel cylinder of the front wheel; disposed between the second hydraulic pressure generation chamber of the master cylinder and the wheel cylinder of the other front wheel of the front wheels A second hydraulic control valve for controlling the brake hydraulic pressure of the wheel cylinder of the front wheel; a control unit for evaluating the skid state of the wheel and issuing a command for controlling the first and second hydraulic control valves; both front wheels Of the brake fluid pressure of the front wheels controlled by the first and second hydraulic pressure control valves, which is disposed between the wheel cylinder of the front wheel and the wheel cylinders of the rear wheels. Out The control unit evaluates the skid state of the front wheels and the rear wheels, and controls the first or second hydraulic pressure control valve by the logical sum of control signals representing the evaluation results. In the anti-skid control device consisting of a brake holding command, a brake slackening command, and a brake stair step-in command for stepwise increasing the brake fluid pressure, from the start or end of the brake slackening command. When the time until the acceleration of the front wheels or the rear wheels reaches a predetermined value is equal to or less than a predetermined length, the first brake fluid pressurizing time in the brake stair insertion is determined according to the duration of the brake slack command. A hydraulic control device for an anti-skid device, which is longer than usual. 3. A pair of front wheels and a pair of rear wheels each of which has a wheel cylinder connected to each other by an X pipe, and is arranged between a first hydraulic pressure generating chamber of the master cylinder and one of the front wheels. A first hydraulic pressure control valve provided to control the brake hydraulic pressure of the wheel cylinder of the front wheel; disposed between the second hydraulic pressure generation chamber of the master cylinder and the wheel cylinder of the other front wheel of the front wheels A second pressure reducing control valve for controlling the brake fluid pressure of the wheel cylinder of the front wheel; a control unit for evaluating the skid state of the wheel and issuing a command for controlling the first and second fluid pressure control valves; It is arranged between the wheel cylinder and the wheel cylinders of both rear wheels, and outputs a pressure according to the lower one of the brake hydraulic pressures of the front wheels controlled by the first and second hydraulic pressure control valves. The control unit evaluates the skid states of the front wheels and the rear wheels, and controls the first or second hydraulic control valve by the logical sum of the control signals representing the evaluation results. The command includes a brake holding command, a brake slack command, and a brake step-in command for stepwise increasing the brake fluid pressure, and the control signal representing the evaluation result is at least when the wheel deceleration is equal to or more than a predetermined deceleration. In a hydraulic control device for an anti-skid device, which includes a deceleration signal indicating that there is an acceleration signal and a wheel acceleration that is equal to or greater than a predetermined acceleration, from the disappearance of the deceleration signal until the generation of the acceleration signal. When the time is less than a predetermined length, the first brake fluid pressurization time in the brake stair insertion is set to the brake slack command. It was longer than the normal case in accordance with the length of the connection time anti-skid device for hydraulic pressure control apparatus according to claim.