JPH1159349A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the required stroke of a brake pedal without sacrificing brake controllability and a pedaling feel. SOLUTION: A stroke simulator 2 which secures the stroke of a brake pedal by contracting springs 60, 61 during the normal operation of a fluid pressure control means is stored in the cylinder main body 30 of a master cylinder 3, and a fluid chamber 59 is formed inside the cylinder main body 30 by a master- cylinder-side piston 34 and a rod 54 interlocked with the brake pedal, with the springs 60, 61 arranged inside the fluid chamber 59; during the normal operation of the fluid pressure control means, a fluid in the fluid chamber 59 is allowed to escape to a reservoir via ports 68, 67 provided in a sleeve 35 and via a port 32 provided in the cylinder main body 30, to perm it contraction of the springs 60, 61; in the event of the failure of the fluid pressure control means, the port 68 is closed by a seal member 65 according to the movement of the piston 34 to seal the fluid inside the fluid chamber 59 to cancel the stroke simulator 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system for a motor vehicle, and more particularly to a brake control device capable of arbitrarily controlling a hydraulic pressure supplied to a wheel brake.

[0002]

2. Description of the Related Art A brake control device of this type generally includes a master cylinder for generating a hydraulic pressure according to the depression force of a brake pedal, and a hydraulic pressure source. Hydraulic pressure control means for adjusting the pressure and supplying the pressure to the wheel cylinder, a fail-safe valve for supplying the hydraulic pressure of the master cylinder to the wheel cylinder when the hydraulic pressure control means has failed, and when the hydraulic pressure control means operates normally. The structure includes a stroke simulator for securing a necessary stroke of the brake pedal.

In such a brake control device, an accumulator or a damper whose volume changes in accordance with the hydraulic pressure of a master cylinder is generally used as the stroke simulator. In this device, however, an accumulator or a damper is supplied. The amount of liquid to be supplied to the wheel cylinder in addition to the amount of liquid to be supplied must be secured in the master cylinder, and a large master cylinder is required.
The increase in the size of the device is inevitable.

Therefore, for example, Japanese Patent Application Laid-Open No. Hei 7-165031
In the brake control device described in the publication, as shown in FIG. 4 excerpted from the publication, a first rod f1 on the master cylinder b side is provided between the brake pedal a and the master cylinder b.
And a pedal feeling adjusting mechanism (stroke simulator) f including a second rod f2 on the brake pedal a side and a spring f3 interposed between the first and second rods f1 and f2. During normal operation of the hydraulic control means, the spring f3 is shortened and the brake pedal a
When the hydraulic pressure control means has failed, that is, when the hydraulic pressure control means is fail-safe, the second rod f2 is brought into contact with the first rod f1 to directly transmit the depression force of the brake pedal a to the master cylinder b. I have to.

[0005]

However, according to the brake control device described in the above publication, when the master cylinder is operated in a fail-safe state, the driver normally applies the master cylinder to the stroke consumed by the stroke simulator f. Since it is necessary to depress the brake pedal a by an amount corresponding to the stroke of the (piston), the brake pedal a must be depressed harder than usual to obtain the same deceleration, which makes the brake operation extremely difficult. There was a problem.

Since the reaction force of the stroke simulator f is determined only by the amount of displacement of the spring f3, there is no speed-dependent component (reaction force increases as the step is stepped on faster) as in general pedal reaction force characteristics. However, there is also a problem that the pedal feeling is uncomfortable in practical use.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to secure a necessary stroke of a brake pedal without sacrificing brake operability and pedal feeling. It is to provide a brake control device provided with a stroke simulator.

[0008]

In order to achieve the above object, the present invention comprises a master cylinder for generating a hydraulic pressure according to the depression force of a brake pedal, and a hydraulic pressure source. Hydraulic pressure control means for adjusting the hydraulic pressure from a hydraulic pressure source and supplying it to the wheel cylinder; a fail-safe valve for supplying hydraulic pressure of the master cylinder to the wheel cylinder when the hydraulic pressure control means fails; A brake simulator that is interposed between a pedal and the master cylinder and includes a stroke simulator that shortens a spring and secures a necessary stroke of a brake pedal during a normal operation of the hydraulic pressure control unit; The simulator is housed in the cylinder body of the master cylinder, and the piston of the master cylinder and the strike are stored in the cylinder body. A liquid chamber is defined by the brake pedal side rod of the brake simulator and the spring of the stroke simulator is disposed in the liquid chamber. Further, the master cylinder is provided with the hydraulic fluid during normal operation of the hydraulic pressure control means. A communication shut-off means is provided for connecting the chamber to the reservoir and for shutting off the communication between the liquid chamber and the reservoir when the hydraulic control means fails.

[0009] With this configuration, when the hydraulic pressure control means fails, the communication shut-off means cuts off the communication between the liquid chamber in which the spring of the stroke simulator is disposed and the reservoir, so that the liquid in the liquid chamber is lost. Is confined, so that the piston of the master cylinder strokes without shortening the spring, so that the brake pedal does not have to be depressed significantly. On the other hand, during normal operation of the hydraulic pressure control means, the spring of the stroke simulator is shortened to secure a necessary stroke of the brake pedal. Since the fluid flows, a reaction force component corresponding to the operation speed of the brake pedal is generated due to the flow resistance, and a desired pedal feeling is secured.

In the present invention, the communication blocking means may be configured to block communication of a liquid passage connecting the liquid chamber and the reservoir in accordance with the movement of the piston of the master cylinder. With this configuration, the communication blocking function can be easily added without providing a special valve mechanism. In this case, an orifice may be provided in the liquid passage, so that the flow resistance of the liquid is further increased, and the pedal feeling is more reliably improved.

[0011]

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

FIG. 2 shows an overall configuration of a brake control device according to the present invention.
A stroke simulator 2 (FIG. 1), which generates a hydraulic pressure according to the operation of the brake pedal 1 (for example, pedaling force) (FIG. 1)
, A hydraulic control device 5 for controlling the hydraulic pressure supplied to the wheel cylinder 4 according to the hydraulic pressure of the master cylinder 3, a master cylinder 1 and a hydraulic control device 5 for the wheel cylinder 4. And a fail-safe valve 6 for selectively connecting the same.

In the present embodiment, the hydraulic control device 5 includes a hydraulic pressure source 7, a hydraulic pressure control valve 8, and an electronic control unit 9.
The hydraulic pressure control valve 8 has a structure as shown in FIG. In FIG. 3, reference numeral 10 denotes an inner hole 1.
0a is a valve body in which a spool 11 is slidably housed, and a valve body 10 has an input port 1 connected to a hydraulic pressure source (AC) 7.
2A, an output port 12B connected to the wheel cylinder (HC) 4 and a discharge port 12C connected to a liquid tank RE (not shown). This valve body 1
0 is connected to a linear solenoid 13 which is operated by supplying current from the electronic control unit (ECU) 9, and its operating rod 13 a is connected to the spool 11.
Is pressed against one end. On the other hand, the hole 1 of the valve body 10
On the bottom side of Oa, a spool 11 is connected to a linear solenoid 13.
A return spring 14 for biasing the spool 11 and a reaction force mechanism 15 for applying an output reaction force to the spool 11 are provided. Reaction mechanism 15
Here, a hydraulic chamber 17 that communicates with the output port 12B via the control pressure flow path 16 is provided.
The control pin 18 includes a control pin 18 slidably extended to 0a, and a spring 19 for urging the control pin 18 to abut its tip against the other end of the spool 11.

In such a hydraulic control valve 8, normally, the spool 6 is at the return position (decompression position) by the spring force of the return spring 14, the input port 12A is closed, and the output port 12B is connected to the discharge port 12C. And is opened to the liquid tank (RE) side through the liquid tank. From this state, the ECU 19
When the linear solenoid 13 is energized, the operating rod 13a moves the spool 11 to the pressure increasing position in accordance with the current flowing therethrough, and while the discharge port 12C is closed, the input port 12A is opened and the hydraulic pressure of the hydraulic pressure Pressure is output port 1
2B to the wheel cylinder 4. At this time, the hydraulic pressure of the output port 12B is transmitted to the hydraulic pressure chamber 17 via the control pressure flow path 16, and the control pin 18 presses the spool 11 rightward in the drawing, whereby a reaction force acts on the linear solenoid 13. When the thrust of the linear solenoid 13 is balanced with the hydraulic pressure in the control chamber 17 and the spring force of the return spring 14, the spool 1
Until 1 closes the input port 12A and the discharge port 12C, the hydraulic pressure at the output port 12B increases, whereby the hydraulic pressure to the wheel cylinder 4 is adjusted according to the current flowing through the linear solenoid 13. .

The electronic control unit 19 supplies a current corresponding to the hydraulic pressure of the master cylinder 3 to the linear solenoid 13 of the hydraulic pressure control valve 8 based on a signal from a hydraulic pressure sensor 20 for detecting the hydraulic pressure of the master cylinder 3. Is supplied to the spool 11 in the hydraulic pressure control valve 8.
Perform the pressure increasing operation as described above, and the hydraulic pressure from the hydraulic pressure source 7 is adjusted and supplied to the wheel cylinder 4. On the other hand, a signal is input to the electronic control unit 19 from a brake lamp switch 21 that detects depression of the brake pedal 1, and the electronic control unit 19 performs a failure based on the signal from the brake lamp switch 21. The safe valve 4 is switched to the hydraulic control device 5 and the hydraulic control valve 8 is operated. The electronic control unit 19 is also supplied with a signal from a hydraulic pressure sensor 22 for detecting a supply pressure to the wheel cylinder 4.
When the hydraulic pressure sensor 23 confirms that the hydraulic pressure does not increase, the electronic control unit 19 returns the fail-safe valve 6 to the position shown in the drawing, and directly transmits the hydraulic pressure of the master cylinder 3 to the wheel cylinder 4. Be able to supply.

Here, the master cylinder 3 incorporating the stroke simulator 2 has a structure as shown in FIG. In the figure, reference numeral 30 denotes a cylinder main body of the master cylinder 3, and the cylinder main body 30 is formed to have a sufficient length to accommodate the entire stroke simulator 2. The cylinder body 30 has a bottomed cylindrical shape, and its peripheral wall is provided with two ports 32 and 33 communicating with a reservoir 31 (FIG. 2). A piston 3 constituting the master cylinder 3 is provided on the inner bottom side of the cylinder body 30.
4 is disposed, and the piston 34 is attached to the cylinder body 3.
The sleeve 35 is slidably guided by the sleeve 35 fitted in the inside. A cup portion 34a is provided at a tip portion (insertion end portion of the cylinder body 30) of the piston 34, and a pressure chamber 36 of the master cylinder 3 is provided between the cup portion 34a and the inner bottom of the cylinder body 30. Is configured as A seal member (cup seal) 37 for sealing the cup portion 34a of the piston 34 in a liquid-tight manner is mounted on the inner surface of the cylinder body 30.

The pressure chamber 36 has a discharge port 38 communicating with the fail-safe valve 6 (FIG. 2). The pressure chamber 36 also has two cup-shaped spring supports 40, which are connected to each other via a shaft member 39 so as to be able to approach and separate from each other.
A spring 42 is provided with both ends seated on 41. The piston 34 is normally urged toward the opening side of the cylinder body 30 by the spring 42, and is positioned at the retreat end where the shaft member 39 extends to the maximum when the master cylinder 3 is not operated.

The end of the sleeve 35 and the intermediate portion thereof are partially adhered to the inner surface of the cylinder body 30 so that an annular chamber 43 is provided around the sleeve 35.
And an annular passage 44 are formed. A sealing member (O-ring) 45 for sealing between the sleeve 35 and the inner surface of the cylinder body 30 is mounted on the intermediate portion.
The annular chamber 43 and the passage 44 are formed by the sealing member 45.
Are isolated from each other so that they cannot conduct with each other. One port 32 provided in the cylinder body 30 is open in the annular chamber 43, and the annular chamber 43 is provided between the port 46 provided in the sleeve 35 and the cup of the piston 34. A port 47 provided in the portion 34a communicates with the pressure chamber 36. The port 47 provided in the cup portion 34a of the piston 34 is
4 is set at a position slightly separated rearward from the seal member 37 at the retracted end of the port 4.
7 wraps around the sealing member 37, and the pressure chamber 36 is defined as a closed chamber.

On the opening side of the cylinder body 30, a second sleeve 50 is fitted. This second sleeve 50
Is connected to a sleeve (hereinafter, referred to as a first sleeve) 35 on the inner bottom side of the cylinder body 30 via a spacer 51 and a stopper ring 52. The rear end of the second sleeve 50 is pressed by a cup-shaped cover 53 screwed into the open end of the cylinder body 30, while the front end of the first sleeve 35 is
Thus, the two sleeves 35 and 50 are fixedly disposed in the cylinder body 30.

A rod 54 constituting the stroke simulator 2 is slidably fitted in the second sleeve 50. The rod 54 is interlocked with the brake pedal 1 by receiving a shaft 1a (FIG. 2) extending from the brake pedal 1 in a recess 54a provided at the rear end thereof. The space between the cylinder body 30 and the second sleeve 50 is sealed by two seal members (O-rings) 55 and 56 attached to the second sleeve 50,
On the other hand, the space between the second sleeve and the rod 54 is sealed by two seal members (cup seals) 57 and 58 attached to the second sleeve 50. This allows
A sealed liquid chamber 59 is defined in the cylinder body 30 by the piston 34 of the master cylinder 3 and the rod 54 of the stroke simulator 2.

The liquid chamber 59 is provided with two springs 60 and 61 constituting the stroke simulator 2. These two springs 60, 61 are provided between a spring receiver 62 mounted on the tip of the rod 54 and a spring receiver 63 mounted on the shaft end of the piston 34 on the master cylinder side via an intermediate free spring receiver 64. They are arranged in series. The combined set load of these two springs 60 and 61 is set lower than the set load of the spring 42 in the pressure chamber 36 on the master cylinder side. Therefore, when the depression force of the brake pedal 1 is applied to the rod 54 in a state where no liquid pressure is generated in the liquid chamber 59, the two springs 60 and 61 are shortened, and the piston 34 on the master cylinder side is immobilized. As it is, only the rod 54 moves (forwards). Note that two springs 60 and 61 having different spring constants are selected.

On the other hand, a seal member (cup seal) 65 for sealing between the piston 34 on the master cylinder side and the first sleeve 35 is mounted. The piston 34 has the cup portion 34a on the distal end thereof and the seal member 65 partially adhered to the first sleeve 35, so that an annular chamber 66 is formed around the piston 34.
Are formed. The annular chamber 66 is communicated with the annular chamber 43 and the annular passage 44 around the first sleeve 35 through ports 67 and 68 provided in the first sleeve 35, respectively.

The seal member 65 has a port 6 communicating with the annular passage 44 at the retreat end of the piston 34.
8 (the liquid chamber 59 side), so that when the master cylinder 3 is not operated, the inside of the liquid chamber 59 is closed by the annular passage 44 around the first sleeve 35, One port 68 of the sleeve 35, an annular chamber 66 around the piston 34, the other port 67 of the first sleeve 35, an annular chamber 43 around the first sleeve 35, and one port of the cylinder body 30. A state of communication with the reservoir 31 through the port 32 is established. A part of one port 68 of the first sleeve 35 is narrowed to an orifice shape.

Further, around the second sleeve 50,
An annular chamber 6 located between the two sealing members 55 and 56
The chamber 69 is provided with a cylinder body 3.
The other port 33 provided at 0 is open. A concave portion 54b communicating with the liquid chamber 59 is provided at the distal end of the rod 54 constituting the stroke simulator 2, and the rod 54 is provided between the concave portion 54b and the annular chamber 69. Port 70 and a port 71 provided in the second sleeve 50. At the retracted end of the rod 54, the port 70 is positioned slightly behind the seal member 58 on the distal end side of the second sleeve 50 (on the open end side of the cylinder body 30). Is inactive, the liquid chamber 59 is filled with the port 70 of the rod 54 and the second
Of the cylinder 50, the annular chamber 69 around the second sleeve 50, and the other port 33 of the cylinder body 30.

Hereinafter, the operation of the brake control device configured as described above will be described. First, a case where the hydraulic pressure control device 5 is operating normally will be described. In this case, the discharge of the liquid in the pressure chamber 36 of the master cylinder 3 is blocked because the fail-safe valve 6 is switched to the hydraulic pressure control device 5 side. Under this condition, when the pedaling force of the brake pedal 1 is transmitted to the rod 54, the two springs 60 and 61 are gradually shortened and the rod 54 moves forward. This rod 5
By the advance of 4, the port 70 wraps around the seal member 58, and the communication between the liquid chamber 59 and the other discharge port 33 of the cylinder body 30 is cut off. And two springs 6
When the combined load of 0,61 exceeds the set load of the spring 42 in the pressure chamber 36, the piston 34 of the master cylinder 3 also advances.
7 is wrapped around the sealing member 37, whereby the pressure chamber 36
The liquid is confined inside, and the piston 34 immediately stops moving.

When the piston 34 is stopped, the seal member 65 provided on the piston 34 is
5 is not wrapped around the port 68 of the
The liquid in the passage 9, the passage 44, the port 68, the chamber 66, the port 6
The air is released from one port 32 of the cylinder body 30 to the reservoir 31 through the chamber 7 and the chamber 43. Accordingly, the two springs 60 and 61 subsequently perform a shortening operation, whereby a necessary stroke of the brake pedal 1 is secured.
That is, the stroke simulator 2 performs an essential simulator function. At this time, the reservoir 3
The flow resistance acts on the liquid discharged to each channel 1 from each flow path, and a reaction force component corresponding to the operation speed of the brake pedal 1 is generated, so that desired pedal feeling is secured. In the present embodiment, in particular, since the port 68 is narrowed in an orifice shape, the flow resistance of the liquid is further increased, and the pedal feeling is further improved. Further, the stroke simulator 2 includes two springs 60 and 61 having different spring constants.
Therefore, the reaction force characteristic varies with time, and a brake feeling similar to that of a normal brake operation can be obtained.

Next, a case where the hydraulic pressure control device 5 has failed will be described. In this case, the fail-safe valve 6 is switched to connect the master cylinder 3 to the wheel cylinder 4, and the liquid in the pressure chamber 36 of the master cylinder 3 is supplied to the wheel cylinder 4 through the discharge port 38. Therefore, when the rod 54 of the stroke simulator 2 moves forward while shortening the two springs 60 and 61 in response to the depression of the brake pedal 1, the piston 34 on the master cylinder side also moves forward in conjunction with this, and finally its sealing member. 6
5 wraps around the port 68 of the first sleeve 35, and the liquid chamber 59 is in a liquid-tight state (hydraulic lock state). Then, the shortening of the two springs 60 and 61 is suppressed,
The piston 34 advances together with the rod 54, and a predetermined hydraulic pressure is supplied to the wheel cylinder 4. That is, the simulator function of the stroke simulator 2 is canceled, so that it is not necessary to depress the brake pedal 1 greatly.

In the above embodiment, as the hydraulic pressure control valve 8 of the hydraulic pressure control device 5, the linear solenoid 13 is provided on the pressure increasing operation side of the spool 11, and the spring force of the spring 14 and the reaction force of the reaction force mechanism 15 are provided. Is used on the pressure reducing side of the spool 11, but the present invention does not limit the type of the hydraulic pressure control valve 8.
No. 031, in which the force of the master cylinder pressure is used on the pressure increasing side of the spool and the force of the linear solenoid is used on the pressure reducing side of the spool, can be used.

[0029]

As described above in detail, according to the brake control device of the present invention, the spring of the stroke simulator is disposed in the liquid chamber provided in the cylinder body of the master cylinder, and the normal operation of the hydraulic pressure control means is achieved. In this case, the spring is shortened by discharging the liquid in the liquid chamber, and when the hydraulic pressure control means fails, the liquid is sealed in the liquid chamber to fix the spring. The required stroke of the brake pedal can be secured without sacrificing. Also, a reaction force component corresponding to the operation speed of the brake pedal is generated due to the flow resistance of the liquid discharged from the liquid chamber,
During normal operation of the fluid pressure control means, a desired pedal feeling can be ensured, and there are some which have great utility value.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a master cylinder with a built-in stroke simulator according to the present invention.

FIG. 2 is a system diagram of a brake control device as one embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a hydraulic control valve used in the present embodiment.

FIG. 4 is a schematic view showing the structure of a conventional stroke simulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Stroke simulator 3 Master cylinder with built-in stroke simulator 4 Wheel cylinder 5 Hydraulic pressure control device 6 Fail safe valve 7 Hydraulic pressure source 30 Cylinder main body 31 Reservoir 32 Port 34 Piston 35,50 Sleeve 36 Master cylinder pressure chamber 54 Stroke Simulator rod 59 Liquid chamber 60, 61 Stroke simulator spring 65 Seal member (communication blocking means) 68 Port (orifice)

Claims (3)

[Claims] 1. A master cylinder for generating a hydraulic pressure according to the depression force of a brake pedal, and a hydraulic pressure source, wherein the hydraulic pressure from the hydraulic pressure source is regulated and supplied to a wheel cylinder according to an operation of a brake pedal. A hydraulic control unit, a fail-safe valve for supplying hydraulic pressure of the master cylinder to a wheel cylinder when the hydraulic control unit fails, and a fail-safe valve interposed between the brake pedal and the master cylinder. And a stroke simulator for shortening a spring and securing a necessary stroke of a brake pedal during normal operation of the pressure control means. The stroke simulator is housed in the cylinder body of the master cylinder, Inside, the piston of the master cylinder and the rod on the brake pedal side of the stroke simulator A liquid chamber is defined and a spring of a stroke simulator is arranged in the liquid chamber. Further, the master chamber is connected to the reservoir when the hydraulic pressure control means is operating normally, and the master cylinder is connected to the reservoir. A brake control device, further comprising a communication cutoff unit that cuts off communication between the liquid chamber and the reservoir when the pressure control unit fails. 2. The communication device according to claim 1, wherein the communication cutoff means is configured to cut off communication between a liquid passage connecting the liquid chamber and the reservoir of the master cylinder in response to the movement of the piston of the master cylinder. Brake control device. 3. The brake control device according to claim 2, wherein an orifice is provided in the liquid passage.