JPH06115421A - Braking force control device of vehicle - Google Patents

Abstract

PURPOSE:To obtain a braking force control device in which a master booster is made unnecessary or reduced in small size. CONSTITUTION:The first chamber R1' and the second chamber R2' to hold a piston 8' between them are communicated through a passage 24 and an aperture 23 provided on the peripheral surface of a piston rod 9', at the position making the first chamber R1' of a control cylinder 7 in the minimum capacity by energizing the piston 8' by a spring 11. When a pressure is fed to the first chamber R1' from a master cylinder by the operation of a brake pedal, the piston 8' is displaced to the right side by the difference of the pressure receiving area between the first chamber side and the second chamber side from the existence or the absence of the piston rod 9'. As a result, the aperture 21 is closed, and the master cylinder pressure is amplified at the ratio of the pressure receiving area, in the second chamber R2' cut off from the first chamber R1', and it is transmitted to a wheel cylinder 19. Consequently, a large size booster is not necessary, and a sufficient braking force is generated even though there is no negative load of the engine and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking force control device.

[0002]

2. Description of the Related Art In a vehicle braking force control system, a brake actuator is provided in its hydraulic circuit to perform antiskid control and traction control of wheels. As a braking force control device of this kind, the applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 3-220052.
There is a proposal in the issue. Here, as shown in FIG. 11, the piston 5 on which the pressure control cylinder 40 is slidable
The piston rod 5 extending from the piston 50 while being divided into the first and second chambers 41 and 42 by 0
1, a screw shaft 53 of a ball screw is formed on the extension of 1, and a nut 54 that engages with the screw shaft 53 is connected to the motor 5
A brake actuator configured to be rotationally driven by 5 to move the piston 50 in the axial direction is used.

This brake actuator is provided with first and second valves 34 and 35, and the first chamber 41 of the control cylinder 40 passes directly through the second valve 35 and the master booster 2 via the first valve 34. To the separate accumulator 45 on the other hand. Second
The chamber 42 is connected on the one hand to the wheel cylinder 19 and on the other hand to the master booster 2 via the second valve 35 and the first valve 34. First chamber 41
And the piston 5 on the axially outer side of the second chamber 42, respectively.
Return springs 57 and 58 for biasing 0 to the neutral position
Is provided. The first valve 34 is an operating check valve configured to allow the working fluid to flow from the control cylinder 40 in the direction of the master booster 2 and prevent the working fluid from flowing in the opposite direction.

When the wheels are in a slipping state, the first valve 3 is instructed by a command from the control unit 70.
4 and the second valve 35 are closed, the high pressure is shut off from the master booster 2 so that the slip ratio becomes a predetermined value, the motor 55 is driven, and the volume of the second chamber 42 is increased. Expanded wheel cylinder 1
Anti-skid control is performed by controlling the hydraulic pressure of 9 to be reduced. In addition, the traction control is performed when the second valve 3
5 is closed, the motor 55 is driven in a direction to reduce the volume of the second chamber 42, the brake pressure is increased, and idling is suppressed.

[0005]

However, in the above braking force control device, in the case of a slow brake where anti-skid control is not required, the piston is not driven positively by the motor, so that the piston is left and right. The return springs 57 and 58 are stopped when the spring forces are balanced. The piston 50 is provided with piston rods 51 and 52 extending on both sides thereof so that the left and right pressure receiving areas are equalized, and the piston 50 is passed from the master booster 2 through the first and second valves 34 and 35 to the first chamber 4
Since the pressures transmitted to the first and second chambers 42 are the same, the piston 50 does not move even when the brake pedal 1 is depressed.

Therefore, the pressure output from the master booster 2 is supplied to the wheel cylinder 19 as it is. That is, since the brake actuator does not have a function of amplifying the pressure from the master booster, in order to supply a sufficient hydraulic pressure to the wheel cylinder, the master booster using a vacuum system or the like must rely solely on the amplification function. Therefore, a large master booster was needed. Providing a brake actuator in the hydraulic circuit and still requiring a large master booster causes an increase in cost and a problem of space. Therefore, in view of the above problems, it is an object of the present invention to provide a braking force control device that does not require a master booster or can be downsized.

[0007]

Therefore, the invention according to claim 1 is to provide a master cylinder, a wheel cylinder, and
A brake actuator provided in a hydraulic circuit that connects the master cylinder and the wheel cylinder, a vehicle state detecting unit, a brake state detecting unit, and a brake actuator is controlled based on signals from the vehicle state detecting unit and the brake state detecting unit. The brake actuator includes a control cylinder that is divided into a first chamber and a second chamber by a piston, and a piston urging unit that urges the piston in a direction that minimizes the volume of the first chamber. A piston drive means for moving the piston in response to a command from the control means, an accumulator connected to the first chamber, a first valve and a second valve for receiving commands from the control means, respectively. The chamber is connected to the master cylinder via the first valve and the second chamber is connected to the wheel cylinder. With the second valve and the first
The pressure receiving area on the first chamber side of the piston is set to be larger than the pressure receiving area on the second chamber side while being connected to the master cylinder via a valve. When the signal indicating the state is received, the first valve is closed to stop the flow of the hydraulic oil from the master cylinder to the control cylinder, and the piston is moved by the piston drive means to increase or decrease the pressure in the second chamber, and the vehicle state When a signal indicating a predetermined idling state of the wheel is received from the detection means, the second valve is closed to stop the flow of hydraulic oil from the second chamber to the master cylinder, and the volume of the second chamber is reduced by the piston drive means. In addition to moving the piston in the direction to increase the pressure in the second chamber, when a signal indicating the brake operating state is received from the brake state detecting means, Especially when the second valve is closed
The pressure in the chamber is set so that the hydraulic pressure from the master cylinder is amplified according to the ratio of the pressure receiving area of the piston.

Further, in the invention described in claim 3, in the above configuration, the brake state detecting means and the second valve are replaced with a component part in which the second valve is closed by the control means in the brake operating state. A brake actuator having a valve corresponding to the first valve, the brake actuator being open when the piston is at a position that minimizes the volume of the first chamber of the control cylinder, and being closed by the displacement of the piston from that position; A valve, the first chamber is connected to the master cylinder via the valve, the second chamber of the control cylinder is connected to the wheel cylinder, and the first chamber is connected to the first chamber via the third valve. , The pressure receiving area of the piston on the side of the first chamber is set to be larger than the pressure receiving area on the side of the second chamber, and when the hydraulic pressure from the master cylinder is received. The piston is displaced to shut off the second chamber from the first chamber, and the pressure in the second chamber is configured so that the hydraulic pressure from the master cylinder is amplified in accordance with the ratio of the pressure receiving area of the piston. And

[0009]

According to the invention of claim 1, the brake actuator is provided with the second valve arranged between the control cylinder second chamber and the master cylinder, and the pressure receiving area of the piston on the first chamber side is larger than that on the second chamber side. Since the second valve is set and the control means closes the second valve when the brake is operated, when the brake is operated, the second chamber is shut off from the master cylinder side by the second valve, and the second chamber has a second chamber. 1
The pressure from the master cylinder supplied to the chamber is amplified corresponding to the ratio of the pressure receiving area of the piston. Since the second chamber is connected to the wheel cylinder,
The output of the master cylinder is amplified and supplied to the wheel cylinder.

By providing the first valve between the first chamber and the second valve and the master cylinder and having the piston drive means, antiskid control and traction control are performed. That is, when the wheel enters a predetermined slip state, the first valve is closed to prevent the high hydraulic pressure from being transmitted from the master cylinder to the control cylinder, and the piston driving means moves the piston to move the second chamber. The volume is changed to increase / decrease the pressure on the wheel cylinder, and the slip is suppressed within the allowable range. Further, when the wheel is in a predetermined idling state, the second valve is closed to seal the second chamber, and the volume of the second chamber is reduced by the movement of the piston by the piston driving means, so that the brake is applied. Even if it is not operated, the hydraulic pressure is supplied to the wheel cylinders to prevent the wheels from idling.

According to the third aspect of the invention, instead of the second valve, the piston is opened when the piston is at a position where the volume of the first chamber of the control cylinder is minimized, and closed when the piston is displaced from the position. Since three valves are provided in the brake actuator and the second chamber is connected to the first chamber via the third valve, when the brake is operated, the piston receiving the hydraulic pressure from the master cylinder is displaced. The second chamber is cut off from the first chamber, and a pressure of a value obtained by amplifying the pressure from the master cylinder supplied to the first chamber according to the ratio of the pressure receiving area of the piston is generated in the second chamber.

When the wheel enters a predetermined slip state during braking operation, the first valve is closed to prevent high hydraulic pressure from being transmitted from the master cylinder to the control cylinder. By the brake operation, the volume of the second chamber closed by the third valve is changed by the movement of the piston by the piston drive means, whereby the pressure on the wheel cylinder is increased or decreased and the slip is suppressed within the allowable range. Further, when the wheel is in a predetermined idling state, the movement of the piston by the piston driving means closes the third valve and reduces the volume of the second chamber, so that the wheel cylinder can be operated even if the brake is not operated. The hydraulic pressure is supplied to prevent the wheels from idling.

[0013]

1 and 2 show an embodiment of the present invention. The driver operates the brake pedal 1 to generate hydraulic pressure in the master cylinder 3. This hydraulic pressure is adjusted by a brake actuator composed of the first valve 4 and the second valve 5 and the actuator main body 20, and then guided to the wheel cylinder 19, whereby the brake caliper 18 including the pad clamps the brake disc 17 and the wheel. Brake. The brake actuator is inserted in each of the brake hydraulic systems of the wheels to be controlled and controls the brake hydraulic system.
There is provided a control unit 12 which receives a rotation speed signal from each target wheel and a brake on / off signal from a brake switch 16 which indicates whether or not the brake pedal 1 is stepped on as brake state detecting means.

The first valve 4 and the second valve 5 receive a command from the control unit 12. First valve 4
Then, the plunger 4b is biased leftward in the figure by the spring 4c, while the spring force of the spring 6b acting to the right of the poppet 6a is set to be weaker than that of the spring 4c.
When the command current from the solenoid to the solenoid 4a is 0, the poppet 6a is pushed leftward. This makes port 6c
Remains open and the ports 6d and 6e communicate with each other.

On the other hand, when a command current is applied from the control unit 12, the solenoid 4a is excited and the plunger 4b is attracted to the right in the figure. As a result, the poppet 6a biased by the spring 6b also moves to the right and closes the port 6c. In this state, the first valve 4 becomes the same as a check valve without operating operation, and the pressure at the port 6d on the master cylinder 3 side is the same as that of the second valve 5.
When the pressure is higher than the pressure of the port 6e on the side, the poppet 6a is pressed to the right by this pressure difference and both ports 6d, 6
When the pressure on the port 6e side is high, the poppet 6a is pushed away and the two communicate with each other.

The second valve 5 is the control unit 1
When a command current is applied from 2, the solenoid 5a is excited and the plunger 5b is attracted to the left to close the valve seat 5c. The port 6e passes through the inside of the second valve 5 and communicates with the port 5d, and also communicates with the port 5e via the valve portion opened and closed by the plunger 5b. The ports 5d and 5e are respectively connected to the first and second chambers R1 and R2 of the control cylinder 7 in the actuator body 20 which will be described later, so that the first valve 4 and the second valve 5 are the same as those described above. It performs the same function as the first valve 34 and the second valve 35 in the proposal.

In the actuator body 20, a control cylinder 7 having end walls 7a and 7b at both ends is divided by a slidable piston 8 into first and second chambers R1 and R2. A piston rod 9 extends through the end wall 7b to the outside of the control cylinder 7. A bearing seal 9c is provided on the end wall 7b at the portion where the piston rod 9 penetrates. A spring 11 acts on the piston rod 9 outside the control cylinder 7 as a piston urging means to urge the piston 8 toward the end wall 7a of the first chamber R1.

Further, the piston rod 9 has a ball screw screw shaft 9a formed on its extension, and is connected to a motor 14 via a nut 13 engaging with the screw shaft. When the motor 14 is rotationally driven based on a command from the control unit 12, a small gear 14 a attached to the motor and a large gear 1 formed on the nut 13 are attached.
3a, screw shaft 9a by the amplified torque
Are driven in the axial direction. As a result, when the motor 14 is rotationally driven, the piston 8 moves inside the control cylinder 7. The motor 14, the small gear 14a, the large gear 13a, the nut 13, and the screw shaft 9a constitute piston driving means.

On the extension of the control cylinder 7 on the first chamber R1 side, a free piston 10b is built in the cylinder 10a adjacent to the end wall 7a, and a spring 10c acts on the free piston 10b via a spring bearing 10d. The accumulator 10 is formed and is connected to the first chamber R1. When the hydraulic fluid flows from the first chamber R1, the accumulator 10 compresses the spring 10c and moves the free piston 10b, so that the pressure change in the first chamber R1 is suppressed only by the amount of bending of the spring 10c.

The end wall 7a is provided with a port 7d communicating with the first chamber R1, and the port 7d communicates with the port 5d of the second valve 5 via an oil passage. The end wall 7b is provided with a port 7e communicating with the second chamber R2, and the port 7e communicates with the port 5e of the second valve 5 via an oil passage. End wall 7
A port 7f communicating with the second chamber R2 is also provided in b, and is connected to the wheel cylinder 19 of the brake caliper 18 via a pipe fixed to the vehicle body to supply hydraulic pressure.

As a result, when the brake pedal 1 is not depressed and the hydraulic pressure in the actuator body is close to zero, the piston 8 is at the position where the volume of the first chamber R1 is minimized by the spring force of the spring 11. When the brake pedal 1 is stepped on and hydraulic pressure is supplied, the control unit 12 causes the solenoids 4a and 5 of the valves to operate.
When all commands to a are 0, the master cylinder 3
The brake pressure generated in the 1st valve 4 and the 2nd valve 5
Through the ports 7d and 7e to enter the first and second chambers R1 and R2. When the second valve 5 is closed and the motor 14 is rotationally driven to move the piston 8, the pressure in the second chamber R2, and hence the pressure on the wheel cylinder 19, increases or decreases in proportion to the driving torque of the motor. Will be done.

In the present apparatus constructed as described above, the flow of the braking control performed by giving a command from the control unit 12 to the first valve 4, the second valve 5 and the motor 14 for each wheel is shown in FIGS. 5 is shown in the flowchart. First, in step 101, it is checked whether or not an ON signal from the brake switch 16 indicating that the brake pedal 1 is depressed is received. When the brake switch 16 is on, the second valve 5 is closed in step 102. The pressure output from the master cylinder 3 is supplied to the control cylinder 7 through the first valve 4.
Is supplied to the first chamber R1.

This pressure causes the piston 8 to move to the first chamber R
From the position where the volume of 1 is minimized, the volume of the second chamber R2 is decreased, and the pressure of the second chamber R2 closed by the second valve 5 is increased. At this time, the piston rod 9
Due to the difference between the pressure receiving area of the piston 8 on the side of the first chamber R1 and the pressure receiving area on the side of the second chamber R2, the pressure from the master cylinder 3 is amplified corresponding to the ratio. And
This amplified pressure is transmitted to the wheel cylinder 19.

During the braking operation as described above, in the next step 103, it is checked whether or not the anti-skid control is already underway. If the anti-skid control is not yet underway, the routine proceeds to step 104, where the wheel The slip condition is detected. The slip state is detected here by the following equation: wheel slip ratio = (actual vehicle speed−wheel speed) / actual vehicle speed, when this slip rate exceeds a threshold value A set as the upper limit of the region where the braking effect is large. Is determined to have slipped violently, step 122
Go to and enter the anti-skid control mode.

In step 122, the wheel cylinder 1
Since the pressure to 9 does not need to be increased any more, the first valve 4 is closed, after which the antiskid control command pressure P (ABS) is calculated in step 123. The control command pressure P (ABS) is the wheel cylinder 19 by this value.
It shows a value in which the slip ratio falls between the threshold A and the threshold C, which are the upper and lower limits of the region where the braking effect is large, when the pressure is changed. In step 124 it is checked if this value is less than zero. When the calculated control command pressure P (ABS) is less than 0, step 10
Proceed to 9. Here, if the control command pressure P (ABS) is 0 or more, that is, if it indicates a pressure increase, it is judged that it is not necessary to perform the anti-skid control, and step 1
25, the first valve 4 is opened, and the control command pressure P (ABS) is set to 0 in step 126.
Go to step 109.

At step 109, the control command pressure P (A
BS) and a traction control command pressure P (TR
The sum of C) is set as the pressure increase / decrease command value F (OUT) given to the piston as the target of the pressure change of the wheel cylinder 19. However, during anti-skid control, the value of the traction control command pressure P (TRC) becomes zero.

In step 110, the pressure increase / decrease command value F (OU
It is checked whether T) is near 0. If this is not near 0, the command value is output to the motor 14 in step 112, and the piston 8 is moved. When the pressure increase / decrease command value F (OUT) is near 0, the pressure control of the wheel cylinder 19 is not required, and the pressure increase / decrease command value F (OUT) is set to 0 in step 111, and a dead zone near 0 is set.

After the start of this anti-skid control, the routine proceeds from step 103 to step 120, where it is monitored whether or not the slip ratio falls below a predetermined threshold value B which is lower than the threshold value C. It is judged that it is not necessary to maintain the pressure inside 7, and in step 121, the first valve 4
Is opened. If the slip ratio is larger than the threshold value B in step 120, the process proceeds to step 122. After step 121 or 122, after step 123,
Similar to the above, control is performed until the control command pressure P (ABS) becomes zero. Further, during the anti-skid control, even if the first valve 4 is closed, when the brake pedal is released, the pressure on the port 6e side becomes relatively higher than that on the port 6d side, and the poppet is pushed away and the first valve 4 is pushed. When the pedaling force is decreased, this is immediately transmitted to the wheel cylinder 19.

When the slip ratio is lower than the threshold value A at step 104, the routine proceeds to step 105, and if the first valve 4 is closed, it is opened and then the first valve 4 is opened.
At step 106, the control command pressure P (ABS) is set to 0, and then the process proceeds to step 107. The threshold is
For example, A = 0.3, B = 0.01, C = 0.1, etc. are set so that the relation of A>C> B is established.

When the brake switch 16 is off in step 101, the routine proceeds to step 130, where it is checked whether or not the traction control is being performed. If the traction control is not yet entered, the routine proceeds to step 131 and the wheels are wheeled. On the basis of the signal from the sensor 15, the idling state of the wheel is checked. If idling is detected here, step 1
Proceeding to 32, the second valve 5 is closed. Then, in the next step 133, the traction control command pressure P
(TRC) is calculated. Traction control command pressure P
(TRC) is a value required to stop idling and achieve an optimum drive state.

In step 134, this P (TRC)
Is checked for a value greater than 0. Here, when the calculated control command pressure P (TRC) is larger than 0, the routine proceeds to step 107. Further, the control command pressure P (T
RC) is less than or equal to 0, that is, indicates that the pressure is reduced, it is determined that it is not necessary to perform traction control,
After the second valve 5 is opened in step 135 and the control command pressure P (TRC) is set to 0 in step 136, the process proceeds to step 107. The steps after step 107 are the same as in the anti-skid control. After starting the traction control, the process proceeds from step 130 to step 132. If idling is not detected at step 131, the routine proceeds to step 137, where the second valve 5 is opened, and then at step 138 the control command pressure P (TR
C) is set to 0, and then the process proceeds to step 107.

This embodiment is constructed as described above, and the pressure receiving area of the piston 8 on the side of the first chamber R1 is set to be larger than the pressure receiving area on the side of the second chamber R2, while the brake pedal 1 is depressed. Since the 2 valve 5 is closed so that the hydraulic pressure from the master cylinder 3 enters only the first chamber R1,
The hydraulic pressure is controlled not only during anti-skid control and traction control but also during gentle braking while these are not required, and the pressure entering the first chamber R1 from the second chamber R2 is amplified according to the ratio of the pressure receiving area. Oil pressure is wheel cylinder 1
9 is supplied.

That is, the hydraulic pressure when the second valve 5 is closed is first sealed in the second chamber R2 of the control cylinder 7. This value is P1. P1 is a value near zero.
While neither the anti-skid control nor the traction control is in progress, both valves 4 and 5 remain open, and the drive command to the motor 14 is also zero. Therefore, the piston 8 is actuated in accordance with the pressure receiving area difference, as shown in FIG. Move slightly to the right from the leftmost position shown in. The movement amount X is the first chamber R1.
Side pressure receiving area is Aa, the second chamber R2 side pressure receiving area is Ab,
If the spring constant of the spring is Kr, then X = P1 (Aa-Ab) / Kr.

When the brake pedal 1 is further depressed to increase the master cylinder pressure to Pm, this master cylinder pressure is transferred to the first chamber R via the first valve 4 in the open state.
Join 1. As a result, the piston 8 moves to the right by Pm
Receive the power of Aa. Therefore, the piston 8 moves in the direction of reducing the volume of the second chamber R2, and the pressure of the second chamber becomes a value Pb different from that of the first chamber R1, and the force due to the pressure Pb in the left direction and the force due to the spring 11 are generated. The forces due to the pressure Pm in the right direction are balanced. In this balanced state, Pm · Aa = Pb · Ab + Kr · X1 holds.

The displacement amount of X1 is the compressibility Bb of the brake fluid.
When the volume from the second chamber R2 to the wheel cylinder 19 is Vb, which is determined by the (volume reduction rate) and the spring constant Kr, ΔX · Ab / Vb = ΔPb · Bb. Therefore, when the initial value is X1 = 0, Pb = 0
Then, X1 = Pb · Bb · Vb / Ab. Substituting this equation into the equation of force balance and solving for Pb gives Pb = Pm · Aa / (Ab + Kr · Bb · Vb / Ab). Here, since the brake fluid is so-called incompressible and the above-mentioned Bb has a very small value, Kr · Bb · V
b / Ab is smaller than Ab, and the above equation can be approximately expressed as Pb = Pm · Aa / Ab. Since Aa is larger than Ab, Pb is increased to a value obtained by multiplying Pm by the pressure receiving area ratio.

As described above, since the pressure from the master cylinder 3 is amplified by the difference in the pressure receiving area of the piston 8 in the brake actuator, unlike the booster using the suction negative pressure of the vehicle engine, even when the engine is stopped. There is an effect that a sufficient brake pressure can be obtained. For this reason, the pressure generated in the master cylinder 3 need only be low, and even when a booster is provided as an auxiliary, a compact, low-capacity one is sufficient.

Next, FIGS. 6 and 7 show a second embodiment in which the second valve in the previous embodiment is abolished in the brake actuator, and its function is incorporated in the control cylinder of the actuator body 20 '. is there. Directly from the port 6e of the first valve 4 to the first chamber R of the control cylinder 7 '.
1'is supplied. The end wall 7b ′ on the second chamber R2 ′ side has a sleeve hole 22, and a piston rod 9 ′ extending from the piston 8 ′ has a land 9d corresponding to the sleeve hole diameter. An opening 23 is provided on the outer peripheral surface of the land 9d, and a passage 24 formed through the piston 8'and the piston rod 9'communicates the opening 23 with the first chamber R1 '. This opening 23 in the piston rod is located in the second chamber R in the position shown where the piston 8'is at the leftmost end.
2 ', and is set to a position where it is closed by the edge 22a of the sleeve hole 22 as soon as the piston moves slightly to the right. This opening 23 and edge 2
2a is a third valve 25 that replaces the function of the second valve
Make up. 9e is a land 9d and a bearing seal 9
It is a relief groove that prevents the oil between c from being sealed.

A port 7d 'is provided on the end wall on the side of the first chamber R1'.
And the cylinder 10a 'of the accumulator 10' is integrated with the end wall, but is connected to the first chamber R1 'as in the previous embodiment. Other configurations are the same as in the previous embodiment, the piston 8'is urged toward the first chamber by the spring 11 acting on the piston rod 9 ', and the piston rod 9'is a ball of which a part is formed. It is movable by a motor 14 by means of a screw, and the second chamber R2 'of the control cylinder has a port 7f'.
It is connected to the wheel cylinder through. On the other hand, the control unit 12 'has no signal from the brake switch as its input.

According to this, when the first valve 4 is opened,
The pressure output from the master cylinder 3 is supplied to the first chamber R1 'of the control cylinder, and this pressure causes the pressure receiving area of the piston 8'on the first chamber R1' side and the second chamber R2 'depending on the presence or absence of the piston rod 9'. Depending on the difference in pressure receiving area on the side,
The piston 8'moves from the position where the volume of the first chamber R1 'is minimized in the direction of decreasing the volume of the second chamber R2'. When the piston is displaced, the opening 23 of the piston rod 9'is closed, and the pressure in the second chamber R2 ', which is cut off from the first chamber, increases. At this time, depending on the ratio of the pressure receiving area,
The pressure from the master cylinder 3 is amplified. And
This pressure is transmitted to the wheel cylinder 19.

In this way, first, in the initial state where the brake pedal 1 is not depressed and the first valve 4 is open, the first chamber R1 'and the second chamber R2' are connected by the passage 24 and are connected to each other. Balanced by pressure. Next, when the brake pedal is depressed, the pressure from the master cylinder 3 displaces the piston 8'to the right and closes the second chamber R2 '.
During this brake operation, when the first valve 4 is closed and the motor 14 is driven to move the piston 8 ', the pressure in the closed second chamber R2' increases and decreases, and the hydraulic pressure to the wheel cylinder 19 increases. Be changed. On the other hand, when the piston 8'is moved to the right by the motor drive while the brake pedal 1 is not stepped on, the second chamber R
2'is closed and its volume is reduced so that high hydraulic pressure is supplied to the wheel cylinder 19.

The braking control in this embodiment is based on the flowcharts shown in FIGS. 8 and 9. First step 2
At 01, it is checked whether or not the anti-skid control is already under way. If the anti-skid control is under way, the routine proceeds to step 220. When anti-skid control is not being performed, it is checked in step 202 whether or not traction control is currently being performed. When the traction control has already been entered, the routine proceeds to step 230.

When the control has not been entered yet, the routine proceeds to step 203, where the slip state of the wheels is detected. When the slip ratio exceeds the upper limit threshold value A in the region where the braking effect is large, the routine proceeds to step 222, and the antiskid control mode is entered. Step 203
If the slip ratio is lower than the threshold value A, the routine proceeds to step 204, and if the first valve 4 is closed, it is opened and then at step 205 the control command pressure P
(ABS) is set to 0, and then the process proceeds to step 206.

In step 206, wheel slipping is detected in order to determine whether or not traction control is necessary.
If idling is not detected, the value of the traction control command pressure P (TRC) is set to 0 in step 207, and the routine proceeds to step 208. If idling is detected in step 206,
Proceeding to step 230, the traction control command pressure P
(TRC) is calculated. In step 231, it is checked whether this value is larger than 0.

Here, the calculated control command pressure P (AB
If S) is larger than 0, the process proceeds to step 208.
If the control command pressure P (ABS) is 0 or less, that is, if it indicates a pressure reduction, it is determined that it is not necessary to perform traction control, and the process proceeds to step 232, where the value of the control command pressure P (TRC) is After being set to 0, the process proceeds to step 208. The previous step 220 or 22
From step 2 onward, steps up to step 226 are the same as steps 120 to 126 of the flow in the first embodiment. At step 208, the control command pressure P (A
The sum of BS) and the traction control command pressure P (TRC) is set as the pressure increase / decrease command value F (OUT) given to the piston as the target of the pressure change of the wheel cylinder 19. The flow up to step 211 thereafter is also the same as in the previous embodiment.

According to this embodiment, the opening 23 of the piston rod and the edge 22a of the end wall sleeve hole 22
Since the third valve 25, which opens and closes according to the displacement of the piston 8 ', has the function of sealing the second chamber of the control cylinder 7', in addition to the effect of the first embodiment, it is provided as a separate body. There is an advantage that the structure of the valve is simplified, a solenoid for operating the valve is not required, and wiring costs associated with the valve and a drive circuit in the control unit are significantly reduced. Further, since the third valve 25 does not require an electric signal and drive for its operation, it has an effect of being able to generate an amplified brake pressure even if the power supply is cut off, and high reliability is obtained. To be

FIG. 10 shows a third embodiment in which another modification is used as the third valve which opens and closes according to the displacement of the piston. In the control cylinder 7 ″ of the actuator body 20 ″, an opening 23 ″ is provided on the outer peripheral surface of a piston rod 9 ″ extending toward the second chamber R2 ″ side of the piston 8 ″, and the opening 23 ″ is provided at the axial center of the piston 8 ″. The bore portion 26 communicated with the bore portion 26 by a passage 24 ". A valve hole 27 that constitutes a valve seat is provided between the bore portion 26 and the first chamber R1 ″. In the bore portion 26, a ball 28 is seated in the valve hole 27 by a spring 29, and the ball 28 is seated in the valve hole 27. It is biased toward closing.

On the other hand, a pusher 30 having a hat-shaped cross section is provided between the end wall 7a on the side of the first chamber R1 "and the accumulator 10, and a pin 30a extends from the hat-shaped top portion toward the piston 8". . This pin has a piston 8 "
Extends into the valve hole 27 of the piston bore portion 26 at the leftmost position in the drawing and pushes the ball 28 to push the bore portion 26R.
1 "communicates with the first chamber. When the piston 8" slightly moves to the right, the pin 30a is relatively retracted so that the ball 28 is seated in the valve hole 27. These balls 28 and pusher 30 substitute the function of the second valve in the first embodiment, and constitute a third valve 25 ″ that opens and closes by displacement of the piston. The pusher 30 is provided with a hole 30b and the accumulator 1 is provided.
0 "and the first chamber R1" are communicated with each other.

The other structure is the same as that of the second embodiment. The first chamber R1 ″ is connected from the port 7d to the port 6e of the first valve 4 shown in FIG. 6, and the motor 14 receives a command from the control unit 12 ′ shown in the same figure. Since the operating positions for sealing and communicating are the same as those in the second embodiment, the braking control is performed here also in accordance with the flow charts of FIGS. 8 and 9.

Also in this embodiment, since the second chamber is sealed by the third valve 25 "which is opened and closed by the displacement of the piston, the structure of the separate valve can be simplified, the cost of the device can be reduced, and the power consumption can be reduced. Amplified brake pressure can be generated with or without supply, and in this embodiment, the spring 2 is additionally used for sealing the second chamber.
Being closed by a ball 28 biased at 9
Further, by further applying the amplified high pressure in the second chamber R2 ″, there is an advantage that leakage is suppressed to a minimum and highly accurate braking performance is exhibited.

[0050]

As described above, according to the present invention, in the brake actuator portion provided for anti-skid control or traction control in the vehicle braking control system, the pressure receiving area on the side of the first chamber that receives the master cylinder pressure of the piston is set to the wheel. The pressure receiving area on the side of the second chamber connected to the cylinder is made larger, and the second chamber of the control cylinder is sealed by the valve that operates when the brake is operated, so the master supplied from the second chamber to the first chamber. The pressure from the cylinder is amplified corresponding to the ratio of the pressure receiving area of the piston, and a pressure is generated and supplied to the wheel cylinder.
As a result, since the master cylinder pressure is amplified in the brake actuator, a separate large-sized and space-consuming booster can be eliminated, or a small booster can be used together. Further, since a power source such as negative pressure is not required, there is an effect that a sufficient brake pressure is generated even when the vehicle engine is stopped. Moreover, since the pressure between the master cylinder and the actuator body is low, the pressure resistance required for the piping between them is also reduced, and the weight and space efficiency of the entire system can be reduced and the cost can be reduced. The effect is that you can do it.

In particular, in the embodiment shown in FIGS. 1 and 2, the first valve and the first valve set for anti-skid control and traction control are used as valves for sealing the second chamber of the control cylinder when the brake is operated. The latter of the two valves, particularly the latter valve, is used as it is, and it has an advantage that it can be easily realized by simply issuing a new command from the control unit when an ON signal is received from the brake switch.

6 and 7, the valve controlled by the control unit is replaced by a combination of an opening provided in the circumferential surface of the land of the piston rod and an edge of the sleeve hole. When the first chamber and the second chamber are communicated with each other when the volume of the one chamber is at the minimum, and when the piston moves from this position, the valve that opens and closes in accordance with the displacement of the piston that blocks the communication is used.
Since it is a valve that seals the chamber, the second valve provided separately from the actuator body is unnecessary, the solenoid for operating the valve is not required, and the accompanying wiring and drive circuit in the control unit. Including the above, there is an effect that a significant cost reduction can be obtained. Furthermore, since the valve that opens and closes with the displacement of this piston does not require an electrical signal and drive for its operation, it operates without interruption even when the power supply is cut off, and the amplified brake pressure is reliably ensured. Has the effect of being able to generate, and high reliability is obtained.

In FIG. 10, since the valve for sealing the second chamber is opened and closed in accordance with the displacement of the piston and has the ball biased by the spring, There is an advantage that the leakage of the oil is suppressed to a minimum and highly accurate braking performance is exhibited.

[Brief description of drawings]

FIG. 1 is a partial view including a valve according to a first embodiment of the present invention.

FIG. 2 is a partial view including a brake actuator body of the first embodiment.

FIG. 3 is a flowchart showing a control flow in the first embodiment.

FIG. 4 is a flowchart showing a control flow in the first embodiment.

FIG. 5 is a flowchart showing a control flow in the first embodiment.

FIG. 6 is a partial view including a valve of the second embodiment.

FIG. 7 is a partial view including a brake actuator body according to a second embodiment.

FIG. 8 is a flowchart showing a control flow in the second embodiment.

FIG. 9 is a flowchart showing a control flow in the second embodiment.

FIG. 10 is a diagram showing a third embodiment.

FIG. 11 is a diagram showing a conventional example.

[Explanation of symbols]

1 Brake Pedal 2 Master Booster 3 Master Cylinder 4 1st Valve 4a Solenoid 4b Plunger 4c Spring 5 2nd Valve 5a Solenoid 5b Plunger 5c Valve Seat 5d, 5e Port 6a Poppet 6b Spring 6c, 6d, 6e Port 7, 7 ', 7 "Control cylinder 7a, 7b, 7b ', 7b" End wall 7d, 7e, 7f Port 8, 8', 8 "Piston 9, 9 ', 9" Piston rod 9a Screw shaft 9c Bearing seal 9d Land 9e Relief groove 10, 10 ', 10 "Accumulator 10a Cylinder 10b Free piston 10c Spring 10d Spring receiver 11 Spring (piston urging means) 12, 12' Control unit (control means) 13 Nut 13a Large gear 14 Motor 14a Small gear 15 Wheel sensor (vehicle state detecting means) 16 Brake switch (brake state detecting means) 17 Brake disc 18 Brake caliper 19 Wheel cylinder 20, 20 ', 20 "Actuator body 22 Sleeve hole 22a Edge 23, 23" Opening 24, 24 "Passage 25, 25 "Third valve 26 Bore part 27 Valve hole 28 Ball 29 Spring 30 Pusher 30a Pin 30b Hole 34 First valve 35 Second valve 40 Pressure control cylinder 41 First chamber 42 Second chamber 45 Accumulator 50 piston 51 piston rod 53 screw shaft 54 nut 55 motor 57, 58 return spring 70 control unit R1, R1 ', R1 "first chamber R2, R2', R2"
Second room

Claims (5)

[Claims] 1. A master cylinder, a wheel cylinder, a brake actuator provided in a hydraulic circuit connecting the master cylinder and the wheel cylinder, a vehicle state detecting means, a brake state detecting means, the vehicle state detecting means, and The brake actuator includes control means for controlling the brake actuator based on a signal from the brake state detecting means, the brake actuator having a control cylinder divided into a first chamber and a second chamber by a piston, and a volume of the first chamber. From the control means, a piston drive means for moving the piston in response to a command from the control means, an accumulator connected to the first chamber, and the control means. The first chamber has a first valve and a second valve respectively The first chamber is connected to the master cylinder via a first valve, the second chamber is connected to the wheel cylinder, and is connected to the master cylinder via the second valve and the first valve. The pressure receiving area on the chamber side is set to be larger than the pressure receiving area on the second chamber side, and the control means closes the second valve when the signal indicating the brake operation state is received from the brake state detection means. The pressure in the two chambers is set such that the hydraulic pressure from the master cylinder is amplified in accordance with the ratio of the pressure receiving area of the piston, and when the signal indicating the predetermined slip state is received from the vehicle state detecting means, the first valve is turned on. The hydraulic pressure is closed to stop the flow of hydraulic oil from the master cylinder to the control cylinder, and the piston is moved by the piston drive means to increase the pressure in the second chamber. When a signal indicating a predetermined idling state of the wheel is received from the vehicle state detecting means, the second valve is closed to stop the flow of hydraulic oil from the second chamber to the master cylinder and the piston driving means is operated by the piston driving means. A braking force control device for a vehicle, characterized in that the piston is moved in a direction of reducing the volume of the second chamber to increase the pressure of the second chamber. 2. The vehicle brake control system according to claim 1, wherein the brake state detecting means is a brake switch attached to a brake pedal and outputting an on / off signal in response to a depression operation of the brake pedal. Power control device. 3. A master cylinder, a wheel cylinder, a brake actuator provided in a hydraulic circuit connecting the master cylinder and the wheel cylinder, a vehicle state detecting means, and the signal based on signals from the vehicle state detecting means. The brake actuator includes control means for controlling the brake actuator, and the brake actuator biases the piston in a direction in which a control cylinder divided into a first chamber and a second chamber by a piston and a volume of the first chamber is minimized. Piston urging means, a piston driving means for moving the piston in response to a command from the control means, an accumulator connected to the first chamber, a valve for receiving a command from the control means, and the piston being the first Open when the volume of one chamber is at the minimum, and closed when the piston displaces from that position. And a third valve,
A chamber is connected to the master cylinder via the valve, the second chamber is connected to the wheel cylinder and the first chamber via the third valve,
The pressure receiving area of the first chamber side of the piston is set to be larger than the pressure receiving area of the second chamber side, and when the hydraulic pressure from the master cylinder is received, the piston is displaced and the second chamber is shut off from the first chamber. However, the pressure in the second chamber is assumed to be the hydraulic pressure from the master cylinder amplified in accordance with the ratio of the pressure receiving area of the piston, and the control means receives a signal indicating a predetermined slip state from the vehicle state detection means. At this time, the valve is closed to stop the flow of the hydraulic oil from the master cylinder to the control cylinder, and the piston is moved by the piston driving means to increase or decrease the pressure in the second chamber. When a signal indicating the idling state of the second chamber is received, the piston driving means moves the piston in a direction of reducing the volume of the second chamber to increase the pressure of the second chamber. Braking force control apparatus for a vehicle, characterized by being composed urchin. 4. The third valve faces an opening provided in a peripheral surface of a piston rod extending from the piston to the second chamber side and communicates with the first chamber, and the second valve provided in the control cylinder. And a sleeve hole for receiving the piston rod, the opening is in the second chamber when the piston is in a position where the volume of the first chamber is minimized, and the sleeve hole is accompanied by displacement of the piston. The braking force control device for a vehicle according to claim 3, wherein an edge of the vehicle is configured to close the opening. 5. The third valve includes a bore portion provided in the piston, the bore portion communicating with the second chamber, the bore portion and the first portion.
A valve hole that connects the chamber, a ball that is biased to close the valve hole in the bore, and a pin that is provided in the control cylinder and that extends from the first chamber side toward the valve hole. Is located at a position where the volume of the first chamber is minimized, the pin separates the ball from the valve hole, and the ball is seated in the valve hole as the piston is displaced. The braking force control device for a vehicle according to claim 3, wherein: