JPS63116967A - Brake pressure controller - Google Patents

Abstract

PURPOSE:To judge manual operation and make it possible to have priority over automatic operation, by detecting differential pressure between both primary and secondary sides of the solenoid on-off valve installed between a master cylinder and a wheel brake. CONSTITUTION:At the time of normal running, a solenoid on-off valves S1 is open but other ones S2 and S3 are close each, and brake pressure corresponding to a pedal 1a is transmitted to a wheel brake 2. Next, when a control part 6 detects a lock trend, the solenoid on-off valve S1 is closed and the S3 is opened, reducing the brake pressure to some extent, and when it comes to a restoring trend, the S3 is closed and the S2 is properly opened or closed, thus pressure goes up. During this while, if a driver relaxes the pedal 1a, hydraulic pressure in a master cylinder 1 is yet more lowered than that of a wheel cylinder 2, so that this is detected by a differential pressure switch 7, opening the solenoid on-off valve S1 and closing others S2 and S3, thereby making manual operation have preference to automatic operation. In this connection, even at time of a wheel spin trend, this manual operation is prior to the automatic operation. Thus, it is suitably usable at varieties of control such as antilock control, traction control, stop holding control, etc.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a brake pressure control device, and more specifically, anti-lock control that prevents wheels from locking when braking a vehicle, and wheels that are prevented from locking due to excessive driving force. The present invention relates to a brake pressure control device that is suitably used to perform control such as traction control to prevent spin.

<Prior Art> Conventionally, brake pressure control devices have been provided that control brake pressure by selectively performing manual operation and automatic operation (for example, U.S. Pat. No. 38170
98, 3893535).

The above-mentioned brake pressure control device includes an electromagnetic on-off valve in the middle of each of the hydraulic piping connecting the mask cylinder and the wheel cylinder, the hydraulic piping connecting the hydraulic pump and the wheel cylinder, and the hydraulic piping connecting the wheel cylinder and the oil tank. are inserted, and by appropriately operating these electromagnetic on-off valves by a control section configured with a computer, either anti-lock control or traction control can be performed.

<Problems to be Solved by the Invention> In order to perform anti-lock control using the brake pressure control device shown in U.S. Pat. No. 3,617,098, it is necessary to In order to make the pressure follow manual operation, it is necessary to configure a check valve that allows flow of hydraulic oil to the mask cylinder side in parallel with the electromagnetic on-off valve between the mask cylinder and the wheel cylinder.

Therefore, even if the automatic operation applies a pressure greater than the manual operation to the foil cylinder, the pressure will be balanced with the manual operation force. That is, it is structurally impossible to increase the brake pressure higher than the manual operating force. Therefore, it is impossible to directly apply this type of anti-lock control device to traction control or stop-holding control.

On the other hand, in order to perform traction control using the brake pressure control device shown in U.S. Pat. The disadvantage is that it cannot be added. In addition, if this mechanism is used as is for anti-lock control, even if the driver releases the brake during lock prevention control, the electromagnetic on-off valve between the mask cylinder and the wheel cylinder will remain closed.
The brake pressure is maintained at a pressure controlled by automatic operation, and the vehicle eventually comes to a stop. Therefore, it is difficult to use the brake pressure control device configured as described above for anti-lock control as is.

Therefore, when performing both anti-lock control and traction control, it is not possible to use any of the above-mentioned brake pressure control devices as is, and it is necessary to adopt a brake pressure control device with another complicated structure. There was a problem.

Purpose of the Invention The present invention has been made in view of the above problems, and provides a brake pressure control device that has a simple structure and can be suitably used for various controls such as anti-lock control, traction control, and stop-holding control. The purpose is to

Means for Solving the Problems> To achieve the above object, the brake pressure control device of the present invention includes a differential pressure that detects which pressure is higher on the primary side and the secondary side of the electromagnetic switching valve. A detection means is provided.

According to the brake pressure control device configured as described above, it is possible to detect which pressure is higher on the primary side or the secondary side of the electromagnetic on-off valve using the differential pressure detection means, so that the brake pressure can be automatically operated. When manual operation is performed during pressure control, it is detected that the pressure levels on the primary and secondary sides of the electromagnetic on-off valve are reversed, and based on this detection signal, manual operation is prioritized over automatic operation. As a result, the brake pressure control device can be applied to various types of control such as anti-lock control, traction control, and stop-holding control.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 1 is a schematic diagram showing a brake pressure control device of the present invention. The brake pressure control device includes a mask cylinder (1) that is manually operated by a brake pedal (1a), a brake wheel cylinder (J), and a hydraulic pump (3) that supplies hydraulic oil in a reservoir tank [4]. ), a pressure accumulator (5) that temporarily stores the hydraulic fluid discharged by the hydraulic pump (3), and an electromagnetic on-off valve (SL) (82) (S3) disposed in the middle of the piping route. and a control section (6) that controls the operation of the electromagnetic on-off valve (SL) (32) (S3).

The mask cylinder (1) and the wheel cylinder (2) are connected via a pipe (Hl), and this pipe (Hl) is connected to the mask cylinder (1) and the wheel cylinder (2).
A pressure accumulator (5) and a reservoir tank (4) are connected to the middle part of the old) via piping (H2) and piping (H3), respectively. Then, an electromagnetic on-off valve (SL) is placed in the middle of the above piping (old), an electromagnetic on-off valve (S2) is placed in the middle of the piping (H2), and an electromagnetic on-off valve (SL) is placed in the middle of the piping (H3).
S3) are inserted respectively. In addition, the above electromagnetic on-off valves (SL) (S2) (S3) each have 2 boats 2
Consists of a position solenoid switching valve.

In addition to the above-mentioned basic configuration, the brake pressure control device of the present invention has the primary side (
A differential pressure switch port is provided to detect which pressure is higher, A) or the secondary side (B). This differential pressure switch (n
As shown in FIG. 2, a fixed electrode (72) and a movable electrode (73) are arranged with a predetermined gap inside a sealed case (71). )
is supported by a diaphragm (74). Further, the upper space (75) of the diaphragm (74) is communicated with the primary side (A) of the electromagnetic on-off valve (Sl) via the boat (pi), and the lower space (7B) is connected to the port (P2).
It is communicated with the secondary side (B) of the electromagnetic on-off valve (Sl) via. Therefore, the pressure on the primary side (A) will change from the pressure on the secondary side (B
), or if the repressure is balanced, the fixed electrode (72) and the movable electrode (78) can be maintained apart. And the primary side (A)
When the pressure on the secondary side (B) becomes higher than the pressure on the movable electrode (
73) can be brought into contact with the fixed electrode (72).

Here, a cable (72) connected to a fixed electrode (72) is shown.
a) and a cable (73) connected to the movable electrode (73).
By determining the presence or absence of conduction between a), it is possible to detect which pressure is higher, the primary side (A) or the secondary side (B).

The control unit [6] includes a vehicle speed sensor (
61), CPU (82), and memory (63), and uses the wheel speed signal from the speed sensor (61) and the signal from the differential pressure switch (sword as input) to make judgments based on a predetermined control program. At the solenoid on-off valve (
SL) (92) (3K) can be operated as appropriate.

An outline of the above operating system is shown in the flowchart of FIG. During normal driving (step ■), the electromagnetic on-off valve (Sl)
is open, and the electromagnetic on-off valve (Sl) (83) is closed, so that brake pressure according to manual operation is transmitted to the wheel brakes.

In step ■, the CPU (62) determines from the wheel speed signal whether or not the wheel has a tendency to lock, and if it does not have a tendency to lock, it determines in step ■ whether or not it has a tendency to spin, and if it does not have a tendency to spin. Maintain normal driving conditions.

If a locking tendency is recognized in step ■, the solenoid shut-off valve (St) is closed in step ■, and the solenoid shut-off valve (St) is closed.
3) to reduce the pressure (brake pressure) in the wheel cylinder (2).

If recovery from the locking tendency is recognized in step (■), the electromagnetic on-off valve (S3) is closed, and the electromagnetic on-off valve (Sl) is closed.
Increase the brake pressure by opening and closing as appropriate (step ■).

If the driver releases the brakes or the road surface conditions change during the above steps ■ to ■, the pressure in the wheel cylinder (2) will recover to the manual operating force (pressure in the mask cylinder (1)). Even if the pressure of the mask cylinder (1) is greater than or equal to the pressure of the wheel cylinder (2), the pressure of the mask cylinder (1) is changed to prevent the next wheel locking tendency from occurring. [Wheel cylinder (2) pressure] In this case, in step (2), it is detected that the output of the differential pressure switch (sword) is reversed (ON), and the process jumps to step (2).In other words, the solenoid on-off valve (Sl) is immediately opened, and the solenoid on-off valve (Sl) is opened. .

(Sl) (S3) is closed, giving priority to manual operation and returning to the normal running state.

On the other hand, if a wheel spin tendency is recognized in step (2), the electromagnetic on-off valve (Sl) is closed and the electromagnetic on-off valve (S1) is opened in step (2) to increase the brake pressure. If recovery from the spin tendency is recognized in step (2), the electromagnetic on-off valve (S1) is closed in step (2), and the brake pressure is reduced by appropriately opening and closing the electromagnetic on-off valve (S3).

If it is determined in step 0 that there is no tendency to spin even though the pressure has been reduced for a predetermined period of time, the process jumps to step 2 and returns to the normal running state.

During the process of step ■■ [stock] ■, that is, during spin suppression control, when the driver operates the brake, [pressure of mask cylinder (1)] ≦ [pressure of wheel cylinder (2)]. What used to be may become [Pressure of master cylinder (1)]> [Pressure of wheel cylinder (2)]. In this case, in step ■, detect that the output of the differential pressure switch ('7) is reversed,
Jump to step ■. In other words, the solenoid on-off valve (
SL) is opened, and the electromagnetic on-off valve (92) (SS) is closed, giving priority to manual operation and returning to normal running conditions.

In this way, when the driver attempts to accelerate or stop when the wheels are predicted to lock or spin, the primary side (A) and secondary side (B) of the electromagnetic on-off valve (Sl)
Since the pressure changes, this pressure change is detected by a differential pressure switch (
7), the control unit (6) can be activated to perform a maneuver in accordance with the driver's intention. Further, by closing all the electromagnetic control valves (81), (92), and (SS), stop-holding control can be performed.

Note that the release of the lock inhibition control and spin inhibition control is delayed by a predetermined period of time after the above control request is issued in order to eliminate the influence of the unstable state immediately after the electromagnetic on-off valve (Sl) is closed. You can do it like this.

FIG. 3 is a sectional view showing another embodiment of the differential pressure switch (7). This differential pressure switch (7) is connected to the cylinder (77
), a piston (78
), and by interlocking with the slide of the piston (78) and bringing the leaf spring-shaped movable contact (79) into contact with and away from the fixed contact (80), It is possible to detect whether the pressure on the primary side (A) or the secondary side (B) of the electromagnetic on-off valve (Sl) is higher.

FIG. 4 is a sectional view showing a differential pressure switch (7) that can detect that the pressures on the primary side (A) and secondary side (B) of the electromagnetic shut-off valve (Sl) are approximately equal. Cylinder(
A first piston (82) and a second piston (83) are configured inside the piston (81), and the narrow diameter portion (82a) at one end of the first piston (82) is connected to the second piston (81). It is fitted into the inner periphery of the piston (83) airtightly and slidably.

Differential pressure switch with the above configuration [If it is a sword, it is a boat (pl
) side pressure is P, boat (P2) side pressure is P1□,
11ゝThe outer diameter of the first piston (82) is
82) of the small diameter portion (Ha) of the Y1 second piston (
83) is 2, then ■ P ox > p eZ2, and the first piston (82) moves to the right in the figure together with the second piston (83), and ■ P -x × P - At Y2, the first piston (82
) moves to the left, and the first piston (82) and the second piston (83) stop at the neutral position shown in the figure.

Therefore, by detecting the positions of the first piston (82) and the second piston (83) by an electrical position detection means (not shown), the electromagnetic on-off valve (Sl)
It is possible to detect not only the magnitude of the primary side (A) pressure and the secondary side (B) pressure, but also the equilibrium state of the side pressures.

The differential pressure switch shown in Figures 2 and 3 (when using a sword, the movable electrode (73) and the fixed electrode (72) come into contact, opening the electromagnetic on-off valve (81) and switching automatic operation to manual operation, so when the electromagnetic on-off valve (Sl) is opened, the foil cylinder (2) The reaction due to the pressure difference with the mask cylinder [1] is transmitted to the brake pedal.However,
When using the differential pressure switch (7') shown in Figure 4,
As soon as the pressures in the wheel cylinder (2) and master cylinder (1) become approximately the same, turn off the differential pressure switch (Sl).
Since the electromagnetic on-off valve (Sl) can be opened, the reaction of the brake pedal when the electromagnetic on-off valve (Sl) is opened can be reduced.

FIG. 5 is a sectional view showing another differential pressure switch port that can detect that the pressures on the primary side (A) and the secondary side (B) of the electromagnetic on-off valve (81) are approximately equal, and (84
) constitutes a piston (85), and in recesses (84a) and (85a) formed in the middle of each of the cylinder (84) and piston (85),
A compression spring (8B) is interposed. The above compression spring (8B
) are provided with engagement rings (87) that are movable in the axial direction.
is provided, and this engagement ring (87) restricts free movement of the piston (85) in the axial direction.

If the differential pressure switch (7') has the above configuration, the boat (
When the pressure on the pi) side is high, the piston (85) is moved to the right in the figure against the spring pressure of the compression spring (8B), and when the pressure on the boat (p2) side is high, the piston (85) is moved to the right in the figure. )
is moved to the left in the figure, and when the pressure is approximately equal again, the spring pressure (85) of the compression spring (8B) causes the piston (85
) can be stopped at the neutral position shown.

Therefore, by detecting the position of the piston (85) using an electrical position detection means (not shown), only the magnitude of the primary side (A) pressure and secondary side (B) pressure of the electromagnetic on-off valve (Sl) can be detected. First, the equilibrium state of repressure can also be detected.

In addition, in the differential pressure switch (7) shown in FIG. 2, by providing another fixed electrode at a symmetrical position to the fixed electrode (72), the primary side (A) pressure and the secondary pressure of the electromagnetic shut-off valve (Sl) can be adjusted. Not only the magnitude of the next side (B) pressure but also the equilibrium state of the repressure can be detected.

<Effects of the Invention> As described above, according to the brake pressure control device of the present invention, it is possible to determine whether the pressure is higher on the primary side or the secondary side of the electromagnetic on-off valve provided between the mask cylinder and the wheel cylinder. can be detected by the differential pressure detection means, so if manual operation is performed during brake pressure control by automatic operation, the height of the pressure on the primary side and the pressure on the secondary side of the electromagnetic on-off valve is reversed. It has the unique effect of being able to easily prioritize manual operation over automatic operation, and being suitable for use in various controls such as anti-lock control, traction control, and stop-holding control.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram showing an embodiment of the brake pressure control device of the present invention, Fig. 2 is a sectional view of a differential pressure switch, Fig. 3, Fig. 4, and Fig. 5 are , a sectional view showing another embodiment of the differential pressure switch, and FIG. 6 is a flowchart of brake pressure control operation. (1)...Mask cylinder (2)...Wheel cylinder (3)...Hydraulic pump (4)...
Reservoir tank (6)...Control unit (7)
...Differential pressure switch (Sl) (S2) (83)...
・Electromagnetic on-off valve patent applicant Sumitomo Electric Industries, Ltd. Figure 4-5 Figure 5

Claims (1)

[Claims] 1. Brake circuit master cylinder and car Block the brake circuit between the wheel brake and Brake with electromagnetic on-off valve for In the pressure control device, the electromagnetic on-off valve Which pressure is higher, the primary side or the secondary side? The provision of differential pressure detection means to detect Features a brake pressure control device. 2. The above differential pressure detection means detects that the primary side is at high pressure. The first position indicates that the the second position indicating pressure, and the primary side The pressure on the secondary side is approximately the same as that of Can detect 3 positions with 3 positions The claimed invention is a differential pressure switch. The brake pressure control device according to item 1 above.