JP2574372Y2 - Vehicle brake fluid pressure control device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control system for a vehicle for preventing, for example, locking or slipping of wheels.

[0002]

2. Description of the Related Art In recent years, in a braking device for an automobile, for example, an anti-lock brake device for preventing wheel lock during sudden braking and a traction control device for preventing traction control from slipping of a driving wheel during sudden acceleration. A control device is provided.

The anti-lock brake device includes a master cylinder that generates a brake fluid pressure in accordance with the amount of depression of a brake pedal, a main passage that transmits the brake fluid pressure in the master cylinder to a wheel cylinder of each wheel,
A recirculation passage for recirculating brake fluid pressure in the wheel cylinder to the reservoir, and a recirculation passage provided near the connection between the main passage and the recirculation passage, for appropriately switching between the main passage and the recirculation passage according to a control current output from a controller; And a three-port three-position switching solenoid valve for controlling. This switching solenoid valve has three ports in a valve body, a master cylinder side passage of a main passage, a wheel cylinder side passage, and a reservoir side passage of a recirculation passage, and a valve body according to a current value supplied to an electromagnetic coil. Are held at three movable positions, and the three ports are appropriately switched and controlled.

If there is a possibility that the wheels may be locked due to the friction coefficient of the road surface at the time of sudden braking, for example, when the brake pedal is suddenly depressed, an electromagnetic control is performed based on a control current from a controller (not shown). While the valve cuts off the communication between the master cylinder side passage and the wheel cylinder side passage, it connects the wheel cylinder side passage with the reservoir side passage to return the brake fluid pressure of the wheel cylinder into the reservoir as shown in FIG. The time pressure reduction control is performed, and thereafter, the ports are closed, and the hydraulic pressure holding control is performed. Further, after the holding control, in order to apply a braking force,
The reservoir side passage is closed, and the pressure increase control is performed by temporarily connecting the master cylinder side passage and the wheel cylinder side passage. After the pressure increase control, the holding signal and the pressure increase signal are output alternately and repeatedly, and the gradual pressure increase control is performed. The precision is improved (for example, see Japanese Utility Model Publication No. 58-17169).

[0005]

However, in the conventional brake fluid pressure control device, as described above, the gradual pressure increase control for suppressing an excessive increase in the wheel cylinder pressure during the antilock control is performed as described above. The convergence of the pressure increase signal and the hold signal for the solenoid valve is repeated, that is, the pressure increase control and the hold control in the wheel cylinder are repeated. Therefore, particularly when switching from the pressure increasing mode to the holding mode, when the master cylinder side passage is closed by the valve body of the solenoid valve, the sudden closing operation causes a water hammer phenomenon due to the brake fluid pressure. As a result, overshoot X of the brake fluid pressure repeatedly occurs in the wheel cylinder as shown in FIG. 6A due to the water hammer phenomenon, thereby causing piping vibration and vehicle body vibration of the hydraulic circuit. As a result, the noise of the vehicle increases, and the occupant feels uncomfortable.

[0006]

This invention SUMMARY OF THE INVENTION, the was devised in view of the conventional circumstances, especially in the valve body of the changeover valve, a pair of valve body to switch in conjunction with the third port to each other with a movably provided, it provided an armature for holding the plurality of movable positions according the valve body to the magnitude of the current value, the wheel cylinder during antilock control
When the pressure is gradually increased, the main passage is
Control the passage area at the open end of the port formed in
Thus, an orifice is formed.

[0007]

During the antilock control, the movable position of the valve body is held at at least four positions via the movable armature with the change in the current value input to the solenoid valve. That is, the current value for the solenoid valve is changed to hold the valve body at the four movable positions, and pressure increase-hold-pressure reduction-hold-slow pressure increase control is performed. In this hold-slow pressure increase control, first, both valve bodies move in one direction in accordance with the current value to close the main passage and the recirculation passage, respectively, and temporarily hold control is performed. one of the valve body through the armature to change is held in a position to reduce the cross-sectional area of slightly port with the movable and the main passage, thereby forming an orifice. Therefore, with the formation of such an orifice, the flow rate of the brake fluid from the master cylinder to the wheel cylinder is regulated, and a gradual pressure increase characteristic with a linear gentle gradient is obtained.

[0008]

1 to 4 show an electromagnetic valve provided for an antilock brake device according to the present invention, and FIG. 5 shows a brake hydraulic circuit of the antilock brake device.

More specifically, reference numeral 1 in FIG. 5 denotes a master cylinder that generates brake fluid pressure in accordance with the amount of depression of a brake pedal 2, 3, 4 denote wheel cylinders on the left and right front wheels, and 5 and 6 denote wheel cylinders on the left and right rear wheels. , 7 connect the master cylinder 1 and the front wheel cylinders 3, 4 to the branch passage portion 7.
a, a primary passage communicating with the master cylinder 1 and rear wheel-side wheel cylinders 5, 6; Reservoir 9,10
Are communicated through the recirculation passages 11 and 12. Also,
The reservoirs 9 and 10 communicate with the primary passage 7 and the secondary passage 8 by return passages 14 and 15 in which a motor pump 13 is provided.

The branch passage portions 7a and 7b of the primary passage 7 and the secondary passage 8 and each of the return passages 1
In the vicinity of the connection point between the control valves 1 and 12, three-port four-position switching solenoid valves 17, 18, and 19 that operate in accordance with the control current from the controller 16 are provided. The controller 16 calculates the slip state of the wheels based on output signals from various sensors such as a wheel speed sensor and a vehicle speed sensor (not shown), and de-energizes the switching solenoid valves 17 to 19 via the relay 20. Alternatively, a control current for each position is output.

Each of the switching solenoid valves 17 to 19 is constructed as shown in FIGS. 1 to 4, wherein reference numeral 21 denotes a bottomed cylindrical valve body whose upper end opening is closed by a magnetic cover 22. Reference numeral 23 denotes a valve. A fixed iron core 25, which is a magnetic material, is provided at the lower end of the inner periphery of the electromagnetic coil 24 in the body 21, and a non-magnetic material holding ring 25 is provided between the fixed iron core 23 and the inner cylindrical portion 22a below the cover 22. is there.

A first port 27 communicating with the master cylinder 1 side of the primary passage 7 or the secondary passage 8 is formed in a cylindrical first passage constituting portion 26 fixed to the inner periphery of the fixed iron core 23. I have. The first passage forming portion 26 has a conical valve seat 28 formed near the inner opening end 27a of the first port 27, and has through holes formed in both side walls of a cylindrical portion 29 provided at an upper end portion. 30 has a guide hole 31 formed in the upper end wall.

The cover 22 has a second port 32 formed on the inner periphery of an outer cylindrical portion 22b provided at an upper end thereof and communicating with the wheel cylinders 3 to 6 side passages.
b, a second tubular passage portion 33 fixed at the center of the upper end portion
A third port 3 communicating with the reservoir 9 and 10 side passages
4 are formed. In addition, the second passage component 33
A conical valve seat 35 is formed near the lower end opening 34 a of the third port 34. Further, a communication hole 37 communicating with the second port 32 is formed in the outer peripheral side of the disk portion 36 fixed to the inner peripheral surface of the outer cylindrical portion 22b, and a guide hole 38 is formed in the center.

In the figure, reference numerals 39 and 40 denote the cover inner cylindrical portion 22.
a, a cylindrical bearing member fixed to each inner peripheral side of the holding ring 25; 41, an armature supported on the inner periphery of the bearing members 39, 40 so as to be movable up and down; 42, 43, an inner side of the armature 41; The vertically movable inlet and outlet valve bodies 44 provided at the up and down positions are disc springs fixed between the lower bearing member 40 and the fixed iron core 23.

The armature 41 has a substantially cylindrical shape, and annular engagement portions 41a and 41b for regulating the vertical movement positions of the valve bodies 42 and 43 are integrally provided on the upper end and the lower inner periphery. . Further, the lower engaging portion 41b and the cylindrical portion 29
Are biased in the upward direction, that is, in the direction away from the fixed iron core 23, by the spring force of the compression coil spring 45 elastically mounted between them, and the maximum upward movement position thereof is regulated by the disk portion 36. ing.

The inlet valve body 42 has a lower engaging portion 4.
1b, a disc-shaped base 42a which comes into contact with the upper surface of the base 1b,
A valve shaft 42b protruding from the center of the lower surface of the valve shaft 2a and slidably guided in the guide hole 31. The valve shaft 42b is provided at the tip end of the valve shaft 42b. And a hemispherical valve portion 42c that opens and closes. A through hole 46 through which brake fluid flows is provided on the outer peripheral side of the base 42a.
Are drilled.

On the other hand, the outlet valve body 43 has the same configuration as the inlet valve body 42,
a, a valve shaft 43b slidably guided in the guide hole 38, and a hemispherical valve portion 43c that detaches and seats on the valve seat 35 to open and close the third port 34. . A through hole 47 is formed in the base 43a.

The two valve bodies 42 and 43 are connected to both base portions 42.
a, 43a, the ports 27, 34 are separated from each other by the spring force of a compression coil spring 48 elastically mounted between them.
Are biased in a direction to close the open ends 27a and 34a of the first and second openings.

The inner circumference of the disc spring 44 is formed so as to rise upward, and the lowering position of the armature 41 is adjusted by a relative force between its own spring force and the magnetic force of the fixed iron core 23. ing.

The operation of this embodiment will be described below.

If the wheels are likely to be locked during rapid braking of the vehicle, the control current from the controller 16 is applied to each of the switching solenoid valves 17, 18, and 19 communicating with the wheel cylinders that may be locked. First, the switching solenoid valves 17 to 19 are in a non-energized state as shown in FIG. 1 at the beginning of the rapid braking, and the armature 41 is urged upward by the spring force of the coil spring 45. This allows
The inlet valve body 42 is moved upward by the lower engaging portion 41b so that the valve portion 42c opens the open end 27a of the first port 27, and the outlet valve body 43 is opened by the spring force of the coil spring 48. The opening end 34a of the third port 34 is closed by the portion 43c. Accordingly, the brake fluid pressure of the master cylinder 1 is increased from the primary and secondary passages 7 and 8 to the first ports 27, the through holes 30, the through holes 46 and 47, the communication holes 37 and The pressure is supplied to each of the wheel cylinders 3 to 6 through the second port 32, and a pressure increase mode as shown in FIG. 6B is set.

Subsequently, a current value A from the controller 16 is applied to each electromagnetic coil 24, and the armature 41 resists the spring force of the coil spring 45 as shown in FIG. Then, the disc spring 44 is slightly compressed, and the disc spring 44 is slightly compressed. This allows
The outlet valve body 43 maintains the state in which the third port 34 is closed, while the inlet valve body 42 is lowered by the spring force of the coil spring 48 with the lowering of the armature 41, and the first port 27 is opened by the valve portion 42c. Close. Accordingly, the supply and discharge of the brake hydraulic pressure to and from the wheel cylinders 3 to 6 are prevented, and the hydraulic pressure holding mode is set.

Next, a certain current value B is applied to the electromagnetic coil 24, and a stronger attractive force is applied to the fixed iron core 23, so that the armature 41 has a strong attractive force as shown in FIG. The disc spring 4 descends against the spring force.
4 is held in the maximum lowered position to completely compress. For this reason, the inlet valve body 42 maintains the closed state of the first port 27, but this time the upper engagement portion 41a pushes down the outlet valve body 43, and thereby the third portion is moved by the valve portion 43c.
The port 34 is opened. Therefore, the brake fluid in the wheel cylinders 3 to 6 flows from the second port 32 to the third port 34 as shown by arrows in the figure, and the reservoirs 9, 1
It returns to 0, and it becomes a pressure reduction mode. In addition, reservoirs 9 and 10
Is returned to the primary and secondary passages 7 and 8 by the motor pump 13.

Further, after the end of the depressurization mode, the above-described holding mode is set, and then the current value C in the electromagnetic coil 24 is applied to apply a slightly smaller attractive force to the fixed iron core 23 than in the holding mode. Is done. Therefore, the armature 41 maintains the lowered state against the spring force of the coil spring 45 by such a small suction force as shown in FIG. The spring 44 is held at a position where it comes into contact with the upper surface thereof without being compressed and lowered. For this reason, the outlet valve body 43
Although the third port 34 is closed, the inlet valve body 42 slightly opens the first port 27 to control the cross-sectional area of the passage to be small, thereby forming an orifice. Accordingly, the brake fluid pressure flowing from the master cylinder 1 to the wheel cylinders 3 to 6 is controlled to a small amount, and the internal pressure rises with a gentle linear gradient as shown in FIG. Here, the current values have a relationship of C <A <B.

Therefore, the water hammering phenomenon of the brake fluid pressure in the slow pressure increasing mode is prevented,
Repetition of the overshoot of the brake fluid pressure due to the conventional switching of the pressure increase-hold control is suppressed,
Piping vibration and vehicle body vibration can be prevented.

During normal braking, the operation is the same as that in the pressure increasing mode, and when the brake pedal 2 is released, the brake fluid in the wheel cylinders 3 to 6 causes the check valves 50 and 50 to operate. Is returned to the master cylinder 1.

[0027]

As is apparent from the above description, in the brake fluid pressure control device according to the present invention, the valve body of the three-port type switching solenoid valve is moved by a plurality of movable members according to the magnitude of the current value. Armature to keep in position, anti-lock control
When the wheel cylinder is gradually increased in pressure,
The passage area at the open end of the port formed in the main passage
Since the orifice is formed by performing the creep control, the gradual pressure increase characteristic of the wheel cylinder during the antilock control can be made a linear and gentle gradient. Therefore, the occurrence of the conventional water hammering phenomenon is prevented, and the repetition of overshoot in the wheel cylinder can be suppressed. As a result, it is possible to reduce the vibration of the piping of the hydraulic circuit, the vibration of the vehicle body, and the vibration noise.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a switching solenoid valve provided in an embodiment of a vehicle brake fluid pressure control device according to the present invention.

FIG. 2 is a longitudinal sectional view showing the operation of the switching solenoid valve.

FIG. 3 is a longitudinal sectional view showing the operation of the switching solenoid valve.

FIG. 4 is a longitudinal sectional view showing the operation of the switching solenoid valve.

FIG. 5 is a schematic diagram showing a brake hydraulic circuit according to the embodiment.

FIG. 6 is a graph showing a comparison between hydraulic pressure change characteristics of a wheel cylinder of the present embodiment and a wheel cylinder of a conventional example.

[Explanation of symbols]

1: Master cylinder, 3-6: Wheel cylinder, 7
... Primary passage (main passage), 8 ... Secondary passage (main passage), 9,10 ... Reservoir, 11,12 ... Reflux passage, 17-19 ... Switching solenoid valve, 21 ... Valve body, 2
7, 32, 34 ... port, 41 ... armature, 42,
43 ... valve body.

Claims (1)

(57) [Scope of request for utility model registration] 1. A main passage for supplying brake fluid pressure generated in a master cylinder to a wheel cylinder, a return passage for returning brake fluid pressure in the wheel cylinder to a reservoir, and a connection between the main passage and the return passage. It provided, in the brake fluid pressure control apparatus for a vehicle that includes a 3-port switching solenoid valve for switching control of the respective passages in accordance with the rotational speed of the wheel, the valve within the body of the changeover valve, interlocking with each other together to provide a pair of valve bodies switching the 3-port movably provided an armature for holding the plurality of movable positions according the valve body to the magnitude of the current values, anti-lock control in
When the wheel cylinder is gradually increased in pressure, the movable position of the valve
The passage at the open end of the port formed in the main passage according to
A brake fluid pressure control device for a vehicle , wherein an orifice is formed by controlling the area to be small .