JPH0537892Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a hydraulic brake system for vehicles, and in particular, the invention relates to a hydraulic brake system for vehicles, and in particular, the invention relates to a hydraulic brake system for vehicles, and in particular, a system in which fluid in a master cylinder is applied to a brake cylinder corresponding to either a front wheel or a rear wheel. The present invention relates to a hydraulic brake device in which fluid of an electromagnetic hydraulic control device is supplied to the brake cylinder corresponding to the other brake cylinder.

[Background of the idea]

A hydraulic brake device generally includes (a) a master cylinder in which a pressurizing piston is disposed in a housing so as to be liquid-tight and movable back and forth, and a pressurizing chamber is formed in front of the pressurizing piston, and (b) the master cylinder has a pressurizing chamber formed in front of the pressurizing piston. (c) an operating force transmission device that is provided between the master cylinder and an operating member such as a brake pedal and transmits the operating force of the operating member to the pressurizing piston as a forward force; , and a brake cylinder that operates a brake that suppresses rotation of the wheel.

Additionally, the hydraulic pressure in the brake cylinder is also electrically controlled. For example, patent application No. 62-55083
As stated in the specification, braking effects commensurate with the brake operating force can always be obtained regardless of variations in the friction coefficient of each brake friction material, the size of the loaded weight, variations in the slope angle of the road surface, etc. When controlling the braking effect during braking, when performing anti-skid control that automatically controls the braking force according to the slip situation that occurs on the wheels during braking, and when performing anti-skid control that automatically controls the braking force according to the slip situation that occurs on the drive wheels when starting or suddenly accelerating. This is performed when performing traction control to generate braking force that appropriately reduces or reduces the driving force in accordance with the

[The problem that the idea attempts to solve]

In a hydraulic brake system, generally, a relatively large amount of brake fluid is sent into the brake cylinder at the beginning of a brake operation to eliminate brake clearance. An example of this can be explained based on the graph in Figure 6. The amount of fluid supplied to the brake cylinder increases rapidly from the beginning of brake operation until the brake cylinder fluid pressure reaches approximately 5 kg/cm ² . After that, it increases at an almost constant slope. This means that the brake fluid was consumed to eliminate the brake clearance until the brake cylinder hydraulic pressure reached approximately 5 kg/cm ² . Therefore, in a hydraulic brake system in which brake fluid from the master cylinder is supplied to the brake cylinder in an amount commensurate with the operating stroke of the operating member, the operating stroke of the operating member increases due to the disappearance of brake clearance. There are problems that cannot be avoided.

This problem also exists in the hydraulic brake device devised earlier by the present inventor. This hydraulic brake device is connected to (a) the master cylinder, (b) the operating force transmission device, and (c) the pressurizing chamber of the master cylinder, and is connected to either the front wheels or the rear wheels of the vehicle. The corresponding first brake cylinder, (d) the second brake cylinder corresponding to the other of the front wheels and the rear wheels, and (e) the hydraulic pressure of the hydraulic pressure source based on the hydraulic pressure of the first brake cylinder. In the case of a lock state, the rear wheels are controlled to a height at which the rear wheels fall at the same time or slightly later than the front wheels, and the electromagnetic hydraulic pressure control device is supplied to the second brake cylinder. The operating stroke of the operating member increases due to the disappearance of the brake clearance of the brake corresponding to this.

The present invention, like the above-mentioned electromagnetic hydraulic control device,
When the operating member is operated, the hydraulic pressure is supplied, and when the brake of at least the first brake cylinder starts to be applied substantially, the pressure is increased according to the amount of operation such as the operating force and stroke of the operating member. The present invention has been made with the object of solving the problem of an increase in the operating stroke of an operating member in a hydraulic brake device equipped with an electromagnetic hydraulic pressure control device that supplies a large amount of hydraulic pressure to a second brake cylinder.

[Means to solve the problem]

The solution to this problem is to combine the hydraulic brake device with the aforementioned master cylinder, operating force transmission device,
The first brake cylinder, the second brake cylinder, the electromagnetic hydraulic pressure control device, and the electromagnetic hydraulic pressure control device are provided in association with the electromagnetic hydraulic pressure control device and the first brake cylinder, and the electromagnetic The present invention includes a flow control device that allows fluid to flow from the hydraulic pressure control device to the first brake cylinder, but shuts off after the period has elapsed.

In one aspect of the present invention, the distribution control device includes:
It includes an on-off valve that is provided in a fluid passage connecting the first brake cylinder and the electromagnetic hydraulic pressure control device, and that opens when the fluid pressure in the fluid passage is below a reference value and closes when it is higher than the reference value. The electromagnetic hydraulic pressure control device is configured to control its own output hydraulic pressure to be higher than the hydraulic pressure of the first brake cylinder until at least the hydraulic pressure in the liquid passage becomes higher than the reference value. The electromagnetic hydraulic pressure control device is further configured to control its own hydraulic pressure in accordance with the operating amount of the operating member at least after the brake of the first brake cylinder starts to be substantially applied.

In another aspect, the electromagnetic hydraulic pressure control device sets its own output hydraulic pressure to be higher than the hydraulic pressure in the pressurizing chamber of the master cylinder for a predetermined period from the start of operation of the operating member, and after the period elapses, the hydraulic pressure is increased. The hydraulic pressure of the electromagnetic hydraulic control device is controlled to be below the hydraulic pressure of the pressure chamber, and a flow control device is installed in the liquid passage connecting the pressure chamber of the master cylinder and the electromagnetic hydraulic control device. When the liquid pressure is higher than the pressure in the pressurized chamber, liquid is allowed to flow from the electromagnetic hydraulic control device to the pressurized chamber, but when the liquid pressure is below the pressure in the pressurized chamber, the liquid is allowed to flow from the pressurized chamber to the electromagnetic hydraulic control device. It shall include check means for blocking the flow of liquid. Further, similar to the above embodiment, the electromagnetic hydraulic pressure control device controls its own hydraulic pressure in accordance with the operating amount of the operating member at least after the brake of the first brake cylinder starts to be substantially applied.

[Effects of action and design]

In the hydraulic brake device according to the present invention, the fluid of the electromagnetic hydraulic pressure control device is supplied to the first brake cylinder and the second brake cylinder, and the electromagnetic fluid A first fill of both brake cylinders is performed by the fluid in the pressure control device.

Therefore, if the above-mentioned predetermined period is selected to be a period until the brake clearance of the first brake completely disappears or almost disappears, when the brake clearance of the first brake is eliminated by the fluid in the master cylinder. Compared to the above, the operating stroke of the operating member can be shortened, and the effect of shortening the braking distance by accelerating the effectiveness of the brake can be obtained.

Further, in an embodiment including the on-off valve, the first
When the hydraulic pressure in the brake cylinder is close to 0 and the hydraulic pressure in the hydraulic passage connecting the electromagnetic hydraulic pressure control device and the first brake cylinder is below the reference value, the hydraulic pressure in the first brake cylinder is higher than that. The hydraulic pressure of the electromagnetic hydraulic pressure control device is supplied, and the first brake cylinder is first filled. Then, the height of the liquid pressure in the liquid passage becomes higher than the standard value,
When the on-off valve closes, the electromagnetic hydraulic pressure control device and the first brake cylinder are completely isolated from each other, and the first fill by the liquid of the electromagnetic hydraulic pressure control device is completed. Therefore, in this embodiment, after the first fill is completed, as long as the hydraulic pressure in the liquid passage is maintained higher than the reference value, the hydraulic pressure in the first brake cylinder and the electromagnetic hydraulic pressure control device are respectively adjusted. You can obtain effects that can be set freely. As is clear from the above description, in this aspect, the period from the start of the brake operation to the closing of the on-off valve corresponds to the predetermined period.

Further, in the embodiment including the non-return means, at the beginning of the brake operation, the hydraulic pressure of the electromagnetic hydraulic pressure control device is higher than the hydraulic pressure of the pressurizing chamber of the master cylinder, and the electromagnetic hydraulic pressure control device The fluid is supplied to the first brake cylinder through a fluid passage connecting it to the pressurizing chamber of the master cylinder, a check means, a pressurizing chamber, etc., and a first fill of the brake cylinder is performed. Thereafter, when the hydraulic pressure in the pressurizing chamber is increased by the action of the pressurizing piston and the hydraulic pressure in the electromagnetic hydraulic control device becomes lower than the hydraulic pressure in the pressurizing chamber, the electromagnetic hydraulic pressure controlling device for the first brake cylinder After the first fill with the liquid is completed, the hydraulic pressure in the first brake cylinder is controlled by the master cylinder, and the hydraulic pressure in the second brake cylinder is controlled by the electromagnetic hydraulic pressure control device.

Note that when the master cylinder fluid is supplied to the first brake cylinder instead of the fluid of the electromagnetic hydraulic control device, the first brake cylinder and the master cylinder are at equal pressure, so the brake clearance of the first brake is There will be no situation where the recovery occurs.

As described above, in this embodiment, the main effect of the present invention can be achieved by relatively inexpensive changes to the control program, control circuit, etc. of the electromagnetic hydraulic control device, without providing the on-off valve. It has the characteristic that an increase in the operating stroke due to the disappearance of brake clearance can be suppressed to a small value.

〔Example〕

Hereinafter, an embodiment in which the present invention is applied to a hydraulic brake system for a four-wheeled vehicle will be described in detail based on the drawings.

Reference numeral 10 in FIG. 1 indicates a brake pedal as an operating member. The brake pedal 10 is connected to a tandem master cylinder 14 (hereinafter simply referred to as master cylinder) via a brake booster 12 as an operating force transmission device.

The master cylinder 14 is well-known, and briefly described, a first pressurizing piston and a second pressurizing piston are disposed in a housing so as to be movable back and forth in series and independently, and both pressurizing pistons A first pressurizing chamber 16 and a second pressurizing chamber 18 are formed in both pistons, respectively. Both pressurizing pistons are always kept at the retracted end position by springs. The master cylinder 14 also includes a liquid chamber 20 connected to both pressurizing chambers 16, 18, and a liquid chamber 20 connected to both pressurizing chambers 16, 18 in a first state in which both pressurizing pistons are located at the backward end position.
However, in the second state in which both pressurizing pistons move forward by a certain small distance or more, liquid flows from the liquid chamber 20 to each pressurizing chamber 1.
6 and 18, and a check means for blocking the flow in the opposite direction. When the brake pedal 10 is operated, each of the pressurizing chambers 16 and 18 is pressurized by the operation of each pressurizing piston, and the pressurizing chambers 16 and 18 are respectively pressurized by the operation of the brake pedal 10. Brake fluid pressures of equal height are generated depending on the force applied. First pressurizing chamber 16 of master cylinder 14
A front wheel cylinder 22 (first brake cylinder) of the front wheel is connected to the front main fluid passage 24 by a front main fluid passage 24 .

Reference numeral 30 indicates a spool type proportional electromagnetic hydraulic control valve (hereinafter simply referred to as a control valve). This is carried out by the accumulator 32 and the accumulator passage 34, by the reservoir 36 and the reservoir passage 38, and by the rear wheel cylinder 40 (second
brake cylinder) and a rear main fluid passage 42, respectively. The control valve 30 was originally applied for in 1986.
This is similar to that described in the specification of No. 170587, and by controlling the excitation current of the solenoid, the hydraulic pressure of the rear wheel cylinder 40 (hereinafter referred to as rear hydraulic pressure) is controlled to a height corresponding to the magnitude of the excitation current. It is something to do.

A two-position valve 44 is provided in the middle of the rear main liquid passage 42, and the rear main liquid passage 46 is divided into a control valve side passage 46 on the control valve 30 side and a wheel cylinder side passage 48 on the rear wheel cylinder 40 side. ing. The two-position valve 44 normally blocks the wheel cylinder side passage 48 from the control valve side passage 46 and connects the second pressurizing chamber 18 of the master cylinder 14 via the liquid passage 50.
However, when the solenoid 52 is excited, the switching valve switches to a state where the wheel cylinder side passage 48 is cut off from the liquid passage 50 and communicated with the control valve side passage 42. That is, the former communication state is a state in which brake fluid supplied from the master cylinder 14 is supplied to the rear wheel cylinder 40, and the latter communication state is a state in which the brake fluid supplied from the master cylinder 14 is supplied to the rear wheel cylinder 40.
This is a state in which brake fluid from the rear wheel cylinder 40 is supplied to the rear wheel cylinder 40.

The output hydraulic pressure of the control valve 30 is also supplied to the liquid chamber 20 of the master cylinder 14 via a liquid passage 60. Since the liquid chamber 20 can be pressurized by the output liquid pressure, if the output liquid pressure is supplied to the front wheel cylinder 22 via the liquid passage 60, the liquid chamber 20, the first pressurizing chamber 16, etc., The front brake will be activated.

A limit valve 62 as an on-off valve is provided in the middle of the liquid passage 60, and until the output liquid pressure of the control valve 30 reaches a height of 3 kg/cm ² , a limit valve 62 is provided between the control valve 30 and the liquid chamber 20. However, when the height of the output liquid pressure becomes greater than 3 kg/cm ² , the spool 64 retreats from the forward end position shown in the figure against the biasing force of the return spring 66, and the liquid passageway is allowed to flow in both directions. It is designed to block 60.

Reference numeral 92 indicates a computer including a CPU, ROM, RAM, input section, output section, and bus. Various sensors are connected to the input section of the computer 92. The various sensors include a brake depression sensor 94 that detects depression of the brake pedal 10, and a depression force sensor 9 that detects the depression force of the brake pedal 10.
6. Accelerator depression sensor 100 detects depression of the accelerator pedal 98 as a speed increasing operation member operated to increase the speed of the vehicle, detects the hydraulic pressure of the front wheel cylinder 22 (hereinafter referred to as front hydraulic pressure) Front hydraulic pressure sensor 102,
A rear hydraulic pressure sensor 104 that detects rear hydraulic pressure, a rear wheel load sensor 106 that detects the load applied to the rear wheels, rotation sensors 108 and 110 that detect the rotation of the left and right front wheels, and a rotation sensor that detects the rotation of the left and right rear wheels. These are sensors 112 and 114. Further connected to the input section are a braking force holding switch 116 and a variable resistor 118 as deceleration setting means. On the other hand, the output section of the computer 92 is connected to the control valve 30 via the first solenoid control circuit 124.
However, the two-position valves 44 are connected through the second solenoid control circuit 126, and the warning light 128 is also connected.
is also connected. The computer 92 controls the rear hydraulic pressure to an appropriate level based on various input signals by executing a control program stored in the ROM (the program shown in the flowchart in FIG. 2), and controls the rear hydraulic pressure to an appropriate level. It is configured to control valve 44 to the proper position. The above control and the functions of the accelerator depression sensor 100, braking force holding switch 116 and variable resistor 118 will be described in detail later.

The liquid in the reservoir 36 is pumped up into the accumulator 32 by a pump 130 and stored at a certain range of liquid pressure. A motor 132 that drives the pump 130 is connected to the output section of the computer 92 via a motor control circuit 134, and the pump 130 is operated according to the hydraulic pressure inside the accumulator 32 detected by an accumulator hydraulic pressure sensor 136. controlled. That is, in this embodiment, the accumulator 32, the pump 130, etc. constitute a hydraulic pressure source corresponding to the control valve 30 (hereinafter referred to as a control valve hydraulic pressure source). Reservoir 3
A level switch 140 is attached to 6,
The computer 92 monitors the liquid level in the reservoir 36.

Next, the operation will be explained.

First, a case will be described in which the braking force holding switch 116 is not operated and only the brake pedal 10 is operated.

The computer 92 in this embodiment is designed to always control the rear hydraulic pressure to be higher than the front hydraulic pressure during normal hydraulic pressure control. Therefore, when the brake pedal 10 starts to be depressed, the control valve 3
0 liquid is in the open state of the limit valve 62 and liquid chamber 2
0, is supplied to the front wheel cylinder 22 via the first pressurizing chamber 16, etc., and first fills the front brake. As a result, the operation stroke of the brake pedal 10 required to eliminate the brake clearance is shortened.

After the output hydraulic pressure of the control valve 30 exceeds 3 kg/cm ² , the limit valve 62 closes and the supply of the liquid of the control valve 30 to the liquid chamber 20 is cut off, and the first fill of the front brake by the liquid of the control valve 30 is interrupted. ends. At this time, the master cylinder 14 and the control valve 30
and are completely isolated from each other by the limit valve 62, so it is possible to freely set the hydraulic pressure of the control valve 30 and, by extension, the height of the rear hydraulic pressure with respect to the front hydraulic pressure.

When the above-mentioned first fill is performed, the driver notices a rapid increase in front hydraulic pressure, that is, 3.
Brake pedal 10 by increasing hydraulic pressure to Kg/ ^cm2
However, by utilizing the jumping action of the brake booster 12, it is possible to suppress the transmission of the reaction force to the driver. That is,
It is sufficient that the reaction force based on the output hydraulic pressure of the brake booster 12 is not transmitted to the brake pedal 10 until the output hydraulic pressure of the brake booster 12 reaches a certain value.

In addition, the fluid pressure at the end of the first fill (3Kg/
cm ² ) is set lower than the hydraulic pressure (5 kg/cm ² ) mentioned above when the brake clearance completely disappears, this is because the front and rear brakes operated by this hydraulic pressure reduce the driver's impact. This is to avoid feeling the speed. The height of the hydraulic pressure at the time of first fill is determined by considering the vehicle weight, brake size, amount of jumping of the brake booster 12, amount of brake fluid required to eliminate brake clearance, initial feeling when the brake pedal 10 is depressed, etc. It will be done.

The above operation will be explained in more detail based on the flowchart of FIG. Note that, with the master cylinder 14 as a border, the control valve 30 and the accumulator 3
2. Control valve side passage 46, liquid passage 60, limit valve 62, etc. on the control valve side, front wheel cylinder 22 and front main liquid passage 24 on the front side, and rear wheel cylinder 40 and wheel cylinder side passage 48 on the rear side. collectively referred to as.

First, a case where the control valve side, the front side, the rear side, and the liquid passage 50 are all in a normal state will be described.

First, in step S1 (hereinafter simply referred to as S1, the same applies hereinafter), the initial flag of the CPU is reset, and in S2, a command is issued to position the 2-position valve 44 to the first position (original position as shown). It can be done. In S3, a pressure reduction command is issued to the control valve 30 to reduce the rear hydraulic pressure to a value of 0, and then in S4 a command to turn off the warning light 128 is issued.

In S5, it is determined whether the braking force holding switch 116 is operated. The current determination result is NO, and the CPU braking flag is reset in S6. Then, in S7, it is determined whether or not the brake pedal 10 is in a depressed state based on the signal from the brake depression sensor 94. Since the brake pedal 10 is currently in the depressed state, the determination result is YES, and it is determined in S8 whether or not the initial flag is set. Since this is the first time in one consecutive brake operation, the first time flag is not set.
The determination result is NO, and S9 is executed.

In S9, a signal representing the rear wheel load is taken in from the rear wheel load sensor 106, and after an initial flag is set in S10, a signal representing the current front hydraulic pressure is taken in from the front hydraulic pressure sensor 102 in S19. In S20a, the pressing force of the brake pedal 10 lowers the front hydraulic pressure by 0.5
It is determined whether the front hydraulic pressure remains below a certain value even though it exceeds the value that should be increased to Kg/cm ² . If the judgment result is YES, that is,
If the front hydraulic pressure is abnormal, the warning light 128 is turned on in S20b, then the release of the brake operation is waited for in S20c, and when the brake operation is released, S1
Return to execution.

If the determination result in S20a is NO, that is, the front hydraulic pressure is normal, a target value for the rear hydraulic pressure is calculated in S21. This is done by executing a hydraulic pressure calculation program (not shown) in the ROM. A calculation formula that uses the rear wheel load and front hydraulic pressure as variables is stored in the ROM, and the target value of the rear hydraulic pressure is calculated using this calculation formula.
As shown in the graph of Figure 3, the target value of the rear hydraulic pressure is set to be slightly smaller than the ideal value of the rear hydraulic pressure corresponding to the front hydraulic pressure and the rear wheel load.
In the event that the vehicle becomes locked, the rear wheels are designed to do so slightly later than the front wheels.

Note that in the region where the front hydraulic pressure is close to 0, the target value of the rear hydraulic pressure is slightly higher than the ideal value, but this is because even if the front hydraulic pressure is 0 at the beginning of the brake operation, the rear hydraulic pressure This is to perform a first fill of the front brake by generating pressure at a slight height. This is because it is necessary. Even with this arrangement, slippage will not occur in the rear wheels due to low rear hydraulic pressure.

Further, in this embodiment, rear hydraulic pressure control corresponding to one consecutive brake operation is performed based on the rear wheel load immediately after the start of the brake operation. FIG. 3 typically shows the case when the vehicle is loaded and when the vehicle is empty.

In S12 of FIG. 2, the control valve 30 is controlled according to the target value, and in S13, the 2-position valve 44 is positioned at the second position, and the rear wheel cylinder 4
0 is in communication with the control valve 30. and,
At the start of brake operation in S14, that is,
It is determined whether a certain period of time has elapsed since the judgment result of S5 or S7 becomes YES, and if it has elapsed, the steps from S15 onward are executed.
If the time has not elapsed, return to execution of S5. In S15, a signal representing the current rear hydraulic pressure is taken in from the rear hydraulic pressure sensor 104, and the determination in S14 is performed in order to increase the reliability of the detected value of this rear hydraulic pressure.

In S16, it is determined whether the height of the rear hydraulic pressure is greater than a reference value. Currently, the control valve side etc. are normal, so the determination result in S16 is YES.

In S17, each rotation sensor 108, 11
The current estimated vehicle speed is calculated based on the signals from 0, 112, and 114, and the decelerations of the left and right rear wheels are calculated, and the larger of the two decelerations is determined to represent the deceleration of the rear wheels. In S18, it is determined whether or not the deceleration is greater than a preset determination value α, thereby determining whether or not excessive slip has occurred in the rear wheels and it is necessary to perform anti-skid control. . Normally, at this point in time, the result of this determination is NO, and the process returns to S5.

If the brake pedal 10 is continuously depressed, the judgment result of S5 is NO and the judgment result of S7 is
YES, and it is determined again in S8 whether or not the first time flag is set. Since this is the second time, the determination result is YES, and S19 and subsequent steps are executed.

Thereafter, the necessity of anti-skid control is determined again in S18, and if the determination result is YES, so-called anti-skid control is performed in S22 to control the rear hydraulic pressure so that the rear wheel slip is at an appropriate amount. This control is repeated until the brake operation is released or the vehicle speed decreases below a certain value close to a stopped state and the determination result in S23 becomes YES. After the anti-skid control is completed, the process returns to S1 and the 2-position valve 44 is activated in S2.
is positioned at the first position, and after the rear hydraulic pressure is lowered by issuing a pressure reduction command to the control valve 30 in S3, the vehicle enters a state in which it waits for a brake operation again in S7.

On the other hand, in the first case where the control valve 30 becomes inoperable as a result of a failure on the front side, in the second case where the control valve 30 becomes inoperable as a result of damage to the liquid passage 50, the control valve itself has failed. In the third case, or in the fourth case where the rear side has failed, the control valve 30
Despite the command to increase the output hydraulic pressure, the rear hydraulic pressure does not increase, and the determination result in S16 becomes NO. In this case, it is determined in S24 whether or not the braking flag is set, and the current determination result is NO, and the two-position valve 44 is returned to the first position in S25. Therefore,
In the first case, the rear brake is operated by the master cylinder 14, in the second case, only the front brake is operated, and in the third case, the master cylinder 14 operates the rear brake. In the fourth case, both the front and rear brakes are operated, and in the fourth case, only the front brake is operated. In either case, it is not possible to first fill the front brake,
Furthermore, the rear hydraulic pressure is not controlled by the control valve 30. The 2-position valve 44 is held at the first position until the brake operation is released and the determination result of S26 becomes YES, and when the brake operation is released, the 2-position valve 44 is held at the first position.
Return to execution.

Next, the operation when the braking force holding switch 116 is operated will be explained. The computer 92 is configured to determine that when the braking force holding switch 116 is operated once, it is in the ON state, and when it is operated again, it is determined to be in the OFF state.

In this case, the determination result in S5 is YES,
Whether or not the brake pedal 10 is operated in S27, and whether the accelerator pedal 9 is operated in S28
It is determined whether or not 8 is being operated. If neither the brake pedal 10 nor the accelerator pedal 98 are operated at this time, S27 and S28
Both determination results are NO, a braking flag is set in S29, and an electric signal corresponding to the position of the variable resistor 118 is fetched in S30. The driver can input the desired deceleration into the computer 92 by operating the driver. Thereafter, in S31, a target value of the rear hydraulic pressure corresponding to the desired deceleration is calculated, and S12 and subsequent steps are executed. Such rear hydraulic pressure control is repeated until the braking force holding switch 116 is operated again and the determination result in S5 becomes NO.

During rear hydraulic pressure control like this, if the judgment result of S16 becomes NO due to a failure on the control valve side, etc.
S24 is executed and the judgment result is YES,
S25 after warning light 128 is turned on in S32
It is starting to get back to running. When the warning light 128 turns on, the driver activates the braking force retention switch 116.
It is possible to know that the operation based on the operation is in a state where it is impossible.

If the brake pedal 10 is operated while the braking force holding switch 116 is in the ON state, S27
The determination result becomes YES, and the execution after S6, that is, the normal control of the rear hydraulic pressure based on the operation of the brake pedal 10 is performed. Furthermore, if the accelerator pedal 98 is operated instead of the brake pedal 10, the determination result in S28 becomes YES, the process returns to S1, and the braking caused by the operation of the braking force holding switch 116 is automatically released.

Note that if the brake force retention switch 116 is operated while the brake pedal 10 is being operated, the determination result in S5 will be YES, but the determination result in S27 will be YES and the process will return to S6 to maintain the braking force. The braking command from switch 116 is ignored.

As is clear from the above description, in this embodiment, the period during which the limit valve 62 is open corresponds to the predetermined period during which first fill is applied to the front brake. The hydraulic pressure source for the control valve, control valve 3
0. Front hydraulic pressure sensor 102, rear wheel load sensor 106, computer 92, which stores and executes steps S1, S3, S7 to S10, S12, S19, and S21 of the flowchart in FIG. The parts constitute an electromagnetic hydraulic pressure control device, and the liquid passage 60 and the limit valve 62 constitute a flow control device. Further, the electromagnetic hydraulic pressure control device of this embodiment controls its own hydraulic pressure according to the hydraulic pressure in the first pressurizing chamber 16 after the hydraulic pressure in the first pressurizing chamber 16 of the master cylinder 14 starts to rise. I'm starting to do that.

In the embodiment described in detail above, the limit valve 62 as an on-off valve is essential for determining the predetermined period during which the liquid in the control valve 30 performs the first fill.
It is possible to omit the limit valve 62 by changing the control program. The embodiment will be explained below based on FIG. 1, FIG. 4, and FIG. Let us express the relationship. Note that the description will be made assuming that the control valve 30 and the liquid chamber 20 of the master cylinder 14 are directly connected to each other via the liquid passage 60.

Hereinafter, the case where only the brake pedal 10 is operated will be described, and the case where the braking force holding switch 116 is operated is the same as in the previous embodiment, so a detailed explanation will be omitted.

When the brake pedal 10 starts to be depressed, as shown in FIG. 5, the mechanical play between the brake pedal 10 and the pressure piston of the master cylinder 14 is eliminated, and then The pressurizing piston starts moving and becomes movable. In this state, when the amount of advance of each pressurizing piston reaches a certain value, the check means causes each pressurizing chamber 16, 18 to be in a pressurizable state where it can be pressurized by the operation of each pressurizing piston. Therefore, when the front brake is not first-filed, the front hydraulic pressure increases as shown by the two-dot chain line in the upper graph of FIG. If we assume that the brake clearance of the front brake completes when the front hydraulic pressure reaches 5 kg/ ^cm2 , then if the first fill is not performed, the brake clearance of the front brake disappears and the front brake The time required for it to actually start to take effect is T ₁ , and this T ₁
The length of is approximately proportional to the operating stroke of the brake pedal 10.

On the other hand, in this embodiment, as shown by the solid line in the upper graph, once the depression of the brake pedal 10 is started, the output hydraulic pressure of the control valve 30 (hereinafter referred to as control pressure) is detected with a slight delay. ) is rapidly increased to 3Kg/cm ² , and the fluid pressure in both pressurization chambers 16 and 18 has already reached 3Kg/cm 2 by the time the pressurization is possible.
Kg/cm ² and the first fill of the front brake is performed. Therefore, the brake clearance of the front brake is completely eliminated by only slightly pressing the brake pedal 10 from the start of the pressurizing state, and the time required for the brake clearance to disappear is _T2 , which is shorter than _T1 above. As a result, the operating stroke will be shorter than when no first fill is performed. Furthermore, as is clear from the lower graph of FIG. 5, the brake clearance of the rear brake is also completely eliminated at almost the same time as that of the front brake.

Hereinafter, the operation of this embodiment will be explained in more detail based on the flowchart of FIG.

Steps S1 to S8 are executed in the same manner as in the previous embodiment. The first determination result in S8 is NO, and S9 and subsequent steps are executed.

After S9 and S10 are performed in the same manner as in the embodiment described above, the target value of the control pressure is set to 3 kg/cm ² in S11, and the control valve 30 is controlled in accordance with this target value in S12. Thereafter, as in the embodiment described above, S13 to S18 are executed, and since this is the first time, the process normally returns to S5.

If the brake pedal 10 is continuously depressed, the judgment result of S5 is NO and the judgment result of S7 is
YES, and it is determined again in S8 whether or not the first time flag is set. In the second determination, the determination result is YES, and the current front hydraulic pressure is detected in S19. In S20a, it is determined whether or not the front hydraulic pressure is abnormal, as in the above embodiment, and in S20, it is determined whether or not the front hydraulic pressure is greater than the reference value of 3Kg/ ^cm2 . It is detected whether the cylinder 14 has reached the pressurizable state. Since only a hydraulic pressure of 3 kg/cm ² is supplied from the control valve 30, if the hydraulic pressure generated in the first pressurizing chamber 16 exceeds 3 kg/cm ² , it is obvious that the master cylinder 14 is ready for pressurization. It turns out that something is true. If the determination result in S20 is NO, the process returns to S11 to maintain the target value of the control pressure at 3 kg/ ^cm2 , while if the result is YES, that is, if the master cylinder 14 is in a pressurized state, the process returns to S11. The target value of the control pressure (rear hydraulic pressure) is calculated based on the front hydraulic pressure and the rear wheel load in the same manner as in the previous embodiment. However, the height of the control pressure is controlled to be lower than the hydraulic pressure in the first pressurizing chamber 16, that is, the height of the front hydraulic pressure. The liquid is prevented from flowing out to the control valve 30 side.

Note that the determination step S20 is provided before the master cylinder 14 transitions to the state where it can be pressurized, and when the front fluid pressure has not yet reached 3 kg/cm ² , S21 is executed and the control is performed. When the target value for pressure (rear hydraulic pressure) is calculated based on the front hydraulic pressure at that time, the target value will be lower than the front hydraulic pressure, and in the end, most of the first fill will be performed before the state can be pressurized. This is to avoid such a situation from occurring.

On the other hand, if the front side, the control valve side, the liquid passage 50, or the rear side itself breaks down, it is the same as in the previous embodiment, and the explanation will be omitted.

As is clear from the above explanation, in this embodiment, from the start of brake operation, the master cylinder 1
The fluid pressure in the first pressurizing chamber 16 of No. 4 is the standard value (3Kg/cm ² )
The period until it becomes higher corresponds to the predetermined period during which the front brake is first filled. Further, the hydraulic pressure source for the control valve, the control valve 30, the front hydraulic pressure sensor 102, the rear wheel load sensor 10
6. The part of the computer 92 that stores and executes the steps S1, S3, S7 to S12, S19, and S21 of the flowchart in FIG. The check means of the master cylinder 14 constitutes a flow control device.

Although not illustrated in detail, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a hydraulic brake system and a front sectional view of a limit valve, which is an embodiment of the present invention, and FIG. 2 is a flowchart showing a hydraulic pressure control program in the above embodiment. FIG. 3 is a graph showing the relationship between the rear wheel load, front wheel cylinder hydraulic pressure, and rear wheel cylinder hydraulic pressure in the above embodiment. FIG. 4 is a flowchart showing a control program for a hydraulic brake system which is an embodiment different from the above-mentioned embodiment, and FIG. This is a graph showing changes in FIG. 6 is a graph showing the amount of brake fluid required to eliminate the brake clearance in relation to the brake cylinder fluid pressure. 10...brake pedal, 12...brake booster, 14...tandem type master cylinder, 2
2...Front wheel cylinder, 30...Spool type proportional electromagnetic hydraulic control valve, 32...Accumulator, 40...Rear wheel cylinder, 62...
Limit valve, 92...computer.

Claims (1)

[Claims for Utility Model Registration] (1) A master cylinder in which a pressurizing piston is disposed in a housing so as to be liquid-tight and movable back and forth, and a pressurizing chamber is formed in front of the pressurizing piston, and the master cylinder. and an operating force transmitting device that is provided between the operating member and the operating member and transmits the operating force of the operating member to the pressurizing piston as a forward force; a first brake cylinder that operates a brake that suppresses the rotation of one of the wheels; a second brake cylinder that operates a brake that suppresses the rotation of the other of the front wheels and the rear wheel; and the operating member is operated. In this case, when the hydraulic pressure is supplied and at least the brake of the first brake cylinder starts to be applied substantially, the hydraulic pressure is increased to a level corresponding to the operating force of the operating member, the operating amount such as the operating stroke, etc. an electromagnetic hydraulic pressure control device that supplies the second brake cylinder; and an electromagnetic hydraulic pressure control device that is provided in connection with the electromagnetic hydraulic pressure control device and the first brake cylinder, and that controls the electromagnetic hydraulic pressure for a predetermined period from the start of operation of the operating member. A hydraulic brake device including a flow control device that allows fluid to flow from the control device to the first brake cylinder, but blocks it after a period of time. (2) The flow control device is provided in a fluid passage connecting the first brake cylinder and the electromagnetic hydraulic pressure control device, and opens when the fluid pressure in the fluid passage is below a reference value, and opens when the fluid pressure is higher than the reference value. The electromagnetic hydraulic pressure control device controls its own output hydraulic pressure to be higher than the hydraulic pressure of the first brake cylinder at least until the hydraulic pressure in the liquid passage becomes higher than the reference value. The hydraulic brake system according to claim 1, wherein the hydraulic brake system controls the hydraulic brake system. (3) The electromagnetic hydraulic pressure control device sets its own output hydraulic pressure to be higher than the hydraulic pressure in the pressurizing chamber of the master cylinder for a predetermined period from the start of operation of the operating member, and after that period has elapsed, the output hydraulic pressure is higher than the hydraulic pressure in the pressurizing chamber. The flow control device is provided in a fluid passage connecting the pressurizing chamber of the master cylinder and the electromagnetic hydraulic pressure control device, and the fluid pressure of the electromagnetic hydraulic pressure control device is controlled to be below When the hydraulic pressure is higher than the hydraulic pressure in the pressure chamber, liquid is allowed to flow from the electromagnetic hydraulic control device to the pressurizing chamber, but when the hydraulic pressure is lower than the hydraulic pressure in the pressurizing chamber, liquid is allowed to flow from the pressurizing chamber to the electromagnetic hydraulic control device. 2. The hydraulic brake device according to claim 1, further comprising check means for blocking the flow of the hydraulic brake.