JPH08276837A - Brake fluid pressure control device built in caliper - Google Patents

Abstract

PURPOSE: To provide a brake fluid pressure control device capable of increasing and decreasing brake fluid pressure smoothly by arranging a pressure adjusting piston for adjusting fluid pressure chamber volume in a wheel cylinder formed in a brake caliper and controlling the movement amount of the pressure adjusting piston. CONSTITUTION: When a fluid pressure is produced in a master cylinder 2, fluid is fed to a fluid chamber 7a, and pushes a piston 6 to the left side in the figure to perform braking action. Also, when wheels are locked during traveling and brake releasing signals are outputted from an electronic control device 15, a solenoid valve 21 is closed, a direct-operated motor 14 is driven, and a cam member 10 is moved. As a result, pressure adjusting pistons 8 are moved on an inclined cam surface 10a by a fluid pressure in the fluid pressure chamber 7a so as to expand the capacity of the fluid pressure chamber 7a and reduce a brake fluid pressure so that a braking force is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact and lightweight brake fluid pressure control device in which a brake fluid pressure control mechanism is incorporated in a caliper of a disc brake, and particularly in a vehicle brake or the like, antilock control and automatic brake control are provided. The present invention relates to a small-sized brake fluid pressure control device that can also be used for traction control and the like.

[0002]

2. Description of the Related Art In recent years, an anti-lock control device has been actively developed for the purpose of improving steering stability during braking and facilitating a driver's driving operation. As an anti-lock control device for this type of vehicle, JP-A-64-4
The thing etc. which were described in the 7650 gazette are known.

The antilock control device described in the above publication has an antilock control modulator arranged in the middle of a pipe connecting a master cylinder and a wheel cylinder,
The ball valve in the modulator is precisely controlled by using a step motor to eliminate the wheel lock phenomenon.

However, in the above antilock control device, in addition to the brake device mounted on the wheel side, a modulator for executing antilock control needs to be provided in the middle of the brake pipe, and the device is large. There is a problem that it will become. Separately, in order to reduce the size of the anti-lock control device, a brake caliper in which a modulator is incorporated has been proposed (Japanese Patent Laid-Open No. 61-166759). This antilock control device incorporates a piezoelectric brake control mechanism in a brake caliper, and performs brake control by utilizing deformation of a piezoelectric element. However, this device has a problem in that it lacks smoothness due to changes in hydraulic pressure, and smooth control of the braking force cannot be performed, and since it is necessary to provide a displacement member for increasing the movement amount of the brake piston, the configuration is complicated. In addition, the manufacturing cost becomes high, and it is difficult to assemble a caliper with a complicated mechanism due to restrictions on weight and size of the caliper located under the spring of the vehicle body. .

[0005]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a pressure adjusting piston for adjusting the volume of the hydraulic pressure chamber is arranged in the wheel cylinder formed in the brake caliper, and the movement amount of the pressure adjusting piston is adjusted to the tuning pressure. By using the cam surface of the cam member that is in contact with the piston to control, a new brake fluid pressure control device that can smoothly increase and decrease the brake fluid pressure is proposed, and an object is to solve the above problems. To do.
Further, in this device, a cam surface is formed in the axial direction of the cam member that controls the movement amount of the pressure adjusting piston, and the cam member is configured to be moved in the axial direction by using a direct drive motor. Therefore, the shape of the cam member can be extremely simplified,
Further, since the cam member is not required to be machined with special precision, the manufacturing cost can be reduced.

[0006]

Therefore, the brake fluid pressure control device incorporated in the caliper according to the present invention has a wheel cylinder 7 formed in the caliper 3 of the brake device and a sliding member arranged in the wheel cylinder 7. Free piston 6
A hydraulic pressure chamber 7a defined in the wheel cylinder 7 by the piston, a valve 21 arranged in a flow path that connects the hydraulic pressure chamber 7a and the master cylinder, and a hydraulic pressure chamber 7a A pressure adjusting piston 8 that can change the volume of the hydraulic pressure chamber and a control mechanism that controls the amount of movement of the pressure adjusting piston 8 are provided, and the control mechanism has a cam surface that contacts the pressure adjusting piston. And a direct acting motor for moving the cam member in the axial direction of the cam member, the cam member being provided on the caliper so as to be movable in the axial direction of the caliper. It is characterized in that the amount of movement of 10 is controlled according to the amount of movement in the axial direction, and this is a means for solving the problem.

[0007]

[Operation] During normal braking When the brake pedal 1 is depressed to generate hydraulic pressure in the master cylinder 2, this hydraulic pressure passes through the master cylinder 2, the flow passage 20 and the open solenoid valve 21 into the hydraulic chamber 7a. The supplied piston 6 is pushed to the left in the figure to execute the braking action.

[During Antilock Control] When the wheels are locked during traveling and a brake loosening signal is output from the electronic control unit 15, the solenoid valve 21 is closed and the direct drive motor 14 is operated.
Is driven to move the cam member 10. As a result, the pressure adjusting piston 8 is moved by the hydraulic pressure in the hydraulic pressure chamber 7a by the inclined cam surface 10a, the volume of the hydraulic pressure chamber 7a is expanded, the brake hydraulic pressure is reduced, and the braking force is weakened. The locked state is released. At the time of repressurization, when the linear motor 14 is rotated in the reverse direction and the cam member 10 is moved in the initial position direction, the inclined cam surface 10a pushes the pressure adjusting piston back into the hydraulic chamber 7a, and repressurization is executed. . When the direct drive motor 14 is stopped, the brake fluid pressure in the fluid pressure chamber 7a is maintained in that state.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of an antilock control device according to a first embodiment as a brake fluid pressure control device of the present invention, FIG. 2 is a side view of the same device, and FIG. 3 is A- in FIG. FIG. In FIGS. 1 and 2, 1 is a brake pedal, 2 is a master cylinder, 3 is a caliper in a brake device, 4 is a disc pad, 5 is a disc, and 6 is a piston for holding a disc pad 4 on one side. Is assembled. A wheel cylinder 7 is formed in the caliper 3, and a piston 6 is slidably arranged in the wheel cylinder 7. The piston 6 defines a hydraulic pressure chamber 7a in the wheel cylinder 7, and the hydraulic pressure chamber 7a communicates with the master cylinder 2 through a flow passage 20. The flow passage 20 is normally open, and antilock control is performed. A valve 21 that is sometimes closed (for example, a normally open solenoid valve) is provided.

A pressure adjusting piston 8 is provided in the hydraulic chamber 7a.
Is provided slidably, and a roller 9 that comes into contact with a cam surface 10a described later is rotatably provided at the end of the piston 8. Cam member (also called cam rod) 1
0 has a cam surface 10a formed thereon.
0 is held by a cam retainer 12 provided on the caliper 3 and a slide bearing 11 provided on the cam retainer, and is configured to be movable in the axial direction while being guided and supported by the cam guide 13 and the slide bearing 11. Cam holder 1
Since 2 has a function of supporting the axial load of the pressure-adjusting piston 8 applied to the cam member 10, the cam member 10 requires almost no strength in the bending direction, and therefore the shape of the cam member can be simplified. The cam retainer 12, the slide bearing 11, the cam guide 13 and the like are covered with a cover 17.

The cam member 10 has a direct-acting type motor 14 (for example, a motor for moving the cam member 10 in its axial direction).
(Voice coil motor, linear motor, etc.) are connected, and the cam member 10 can be moved in the axial direction by driving the linear motion motor 14.
Further, as shown in FIG. 3, a cam surface 10a for controlling the moving amount of the pressure adjusting piston 8 is formed on the surface of the cam member 10 which faces the pressure adjusting piston 8. The cam surface 10a is formed as an inclined surface having a wedge-shaped cross section in the axial direction,
The amount of movement of the pressure adjusting piston 8 is controlled by this inclined surface,
It has the function of increasing or decreasing the hydraulic pressure in the hydraulic chamber 7a. Since this inclined surface is wedge-shaped, the wedge effect is exerted when the cam member moves, and even if the driving force of the linear motor is not very strong,
The pressure adjusting piston can be driven. It should be noted that by adopting variously shaped cam surfaces for this cam surface, it is possible to freely select the increase or decrease of the hydraulic pressure in the hydraulic chamber, which enables anti-lock control, traction control described later, automatic brake control, etc. Brake hydraulic pressure control according to various aspects can be performed. The cam member and the direct drive motor constitute a control mechanism for the amount of movement of the pressure adjusting piston.

The valve 21 and the direct drive motor 14 described above are connected to an electronic control unit (ECU) 15, and the electronic control unit 15 operates on the basis of signals from various sensors 16 such as a speed sensor and an inter-vehicle distance sensor. The direct drive motor 14 is driven, and the solenoid valve 21 is operated to execute anti-lock control, automatic brake control, traction control, etc. in a manner described later. In addition, 2 in FIG.
Reference numeral 4 is a seal between the piston 6 and the cylinder 7, which has a piston returning function, 26 is a dust seal, and 25 is a seal member.

The operation of the antilock control device according to the above configuration will be described. [Normal Braking] During normal braking, there is no command from the electronic control unit, and the valve 21 and the motor 14 do not operate. Further, since the cam member 10 takes the initial position shown in FIG. 2 and the pressure regulating piston 8 does not operate, the pressure regulating piston 8
Maintains the state shown in FIG. Therefore, in this state, when the brake pedal 1 is depressed and hydraulic pressure is generated in the master cylinder 2, this hydraulic pressure is supplied to the hydraulic chamber 7a through the master cylinder 2, the flow passage 20, and the open solenoid valve 21. The piston 6 is pushed leftward in the figure to execute the braking action. When the depression of the brake pedal is released, the hydraulic pressure in the hydraulic chamber 7a is returned to the master cylinder in the route opposite to the above, and the brake is released.

[During Antilock Control] When the brake pedal 1 is depressed to brake the vehicle, hydraulic pressure is generated in the master cylinder 2. As described above, this hydraulic pressure is supplied to the hydraulic chamber 7a in the wheel cylinder to apply a braking force to the wheels. By the way, in this state, the state of the wheel is always detected by the speed sensor 16, and the detection signal is input to a known electronic control unit, and the electronic control unit inputs the wheel speed, the slip ratio, and the deceleration based on the input. And so on.
Then, the skid state of the wheel is evaluated based on this calculation result, and the valve 21 and the direct drive motor 14 are controlled as described below to execute various modes such as depressurization, holding and repressurization of the brake fluid pressure.

That is, when the wheels are locked during traveling and the brake release signal is output from the electronic control unit (ECU) 15, the solenoid valve 21 is closed and the direct drive motor 14 is driven to move the cam member 10 to the position shown in FIG. Move to the center right. As a result, the inclined cam surface 10a causes the pressure adjusting piston 8 to move upward in the drawing due to the hydraulic pressure in the hydraulic chamber 7a, which expands the volume of the hydraulic chamber 7a to reduce the brake hydraulic pressure and weaken the braking force. Thus, the locked state of the wheels is released.

Further, at the time of re-pressurization, when the linear motor 14 is rotated in the reverse direction and the cam member 10 is moved toward the initial position, the inclined cam surface 10a pushes the pressure adjusting piston back into the hydraulic chamber 7a and re-applies. Pressure is executed. Further, when the command for holding the brake fluid pressure is issued, the direct drive motor 14 is stopped and the brake fluid pressure in the fluid pressure chamber 7a is held in that state. As described above, according to this embodiment, the pressure in the hydraulic chamber 7a is
It is controlled by the operation of the pressure-adjusting piston 8 in accordance with the movement of the cam member in the axial direction, whereby the brake fluid pressure can be reduced, held, and repressurized.

Further, the hydraulic pressure control (pressure reduction, holding, repressurization) of the brake device is performed independently or for each wheel of each channel according to the state of each wheel. The antilock control is released when the signal from the electronic control unit disappears. That is, when the signal from the electronic control device disappears, the linear motion motor 14 returns the cam member 10 to the initial position, and the pressure adjusting piston also returns to the initial position to enter the state of FIG. 1 and the normal braking state.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment shows an example in which the mounting position of the direct acting motor can be changed variously, and the alternate long and short dash line in the figure indicates the changing position of the direct acting motor. Since the linear motor may be arranged anywhere due to its function, the mounting position can be changed according to the surrounding conditions. Therefore, when the position of the linear motor is changed, the arrangement of the cam members is changed accordingly, and the positions of the cam rod and the cam presser are naturally changed.

Further, another embodiment of the cam surface for performing antilock control, automatic brake control, or traction control according to the present invention will be described with reference to FIG. In this example, in order to enable anti-lock control, automatic brake control, traction control, etc. with one cam member, a cam surface as shown in the figure is formed on the cam member 10, and, for example, an inter-vehicle distance sensor or a speed sensor is used. Sensor 1
By controlling the solenoid valve 21 and the motor 14 in accordance with the signal from the control unit 6, various modes such as pressure increase, pressure decrease, holding, repressurization of the brake fluid pressure are executed.

Specifically, when the cam member 10 moves to the right from the initial position in FIG. 5, the pressure adjusting piston 8 moves in the direction in which it is pushed out of the hydraulic chamber 7a, and antilock control can be executed. Further, when the cam member moves to the left from the initial position in FIG. 5, the pressure adjusting piston 8 moves in the direction of pushing into the hydraulic chamber 7a to brake the wheels and perform automatic brake control or traction control. Can be executed. In addition to the shape shown in FIG. 5, the cam surface 10a
It is also possible to easily select various braking operation modes (for example, abrupt pressure increase, pressure decrease, gradual pressure increase, pressure decrease, a combination thereof, etc.) by devising various shapes. In the above embodiment, various valves such as a solenoid valve can be applied to the valve, and it goes without saying that various mechanisms capable of moving the cam member in the axial direction can be adopted instead of the direct drive motor.

[0021]

As described above in detail, according to the present invention, the pressure adjusting piston is arranged in the wheel cylinder formed in the brake caliper, and the movement amount of the pressure adjusting piston is controlled by using the cam mechanism. By controlling the volume in the cylinder and increasing / decreasing the brake fluid pressure to execute anti-lock control and various other brake controls,
The mechanism incorporated in the caliper is simplified, and the antilock control device and the like can be manufactured in extremely small size and at low cost. Further, since the hydraulic pressure control is executed by the cam member that is swingably provided on the caliper, the hydraulic pressure control can be executed smoothly and the control accuracy such as the antilock control can be improved. Since the shape of the cam member can be extremely simplified and the accuracy is not so required, there is a great merit in manufacturing. Furthermore, by changing the shape of the cam surface, 1
This device can be used not only for anti-lock brake control, but also for automatic braking for inter-vehicle distance control and traction control for slip prevention when starting. Further, since the shape of the cam member is simple and the mounting angle of the linear motor can be easily changed, the layout at the time of mounting can be freely selected. Since the caliper 3 that constitutes the brake device is located under the spring of the suspension of the vehicle, it is desirable that the antilock control device and the like incorporated in the caliper be as small as possible. However, the brake fluid pressure control device according to the present invention has such a demand. It is also possible to deal with. It is possible to achieve excellent operational effects such as.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a brake fluid pressure control device as a first embodiment according to the invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a schematic configuration diagram of a brake fluid pressure control device as a second embodiment according to the present invention.

FIG. 5 is an embodiment of another cam member according to the present invention.

[Explanation of symbols]

 1 Brake Pedal 2 Master Cylinder 3 Caliper 4 Disc Pad 5 Disc 7 Wheel Cylinder 7a Hydraulic Chamber 8 Pressure Control Piston 9 Roller 10 Cam Member 10a Cam Surface 11 Sliding Bearing 12 Cam Presser 13 Cam Guide 14 Motor (Drive) 15 Electronic Control Device 16 Sensor 17 Cover 20 Flow path 21 Valve

Claims (3)

[Claims] 1. A wheel cylinder 7 formed in a caliper 3 of a brake device, a slidable piston 6 arranged in the wheel cylinder 7, and a hydraulic chamber defined in the wheel cylinder 7 by the piston. 7a, a valve 21 arranged in a flow path that communicates the hydraulic chamber 7a with the master cylinder, and a pressure adjusting piston 8 capable of changing the volume of the hydraulic chamber that appears in and out of the hydraulic chamber 7a. A control mechanism for controlling the amount of movement of the pressure adjusting piston 8, the control mechanism having a cam surface in contact with the pressure adjusting piston, and being provided on the caliper so as to be movable in its own axial direction. And a direct-acting motor that moves the cam member in the axial direction of the cam member.
A brake fluid pressure control device incorporated in a caliper, characterized in that the movement amount is controlled according to the movement amount in the axial direction. 2. The built-in caliper built-in brake according to claim 1, wherein the cam member is configured to move in the axial direction of the cam member while being supported by a slide bearing provided on the caliper side. Hydraulic control device. 3. The brake fluid pressure control device incorporated in a caliper according to claim 1, wherein the direct drive motor is a voice coil motor.