JP2665613B2 - Anti-lock braking system for automobiles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake device for an automobile, and more particularly to an antilock brake device for an air over brake using a brake booster and a modulator. is there.

<Prior Art> In order to improve the braking performance of an automobile service brake, for example, an antilock brake device as shown in FIG. 3 has been used. Explaining this anti-lock brake device, the air discharged from the compressor a and stored in the air tank b is supplied to a brake booster e via a brake valve d operated by a brake pedal c. When air is supplied to the brake booster e, the oil supplied to the brake booster e from the oil reservoir f is pressurized, and the hydraulic pressure (brake pressure) responsive to the pressure of the air output from the brake valve d is applied to this brake. The output from the booster e is supplied to the cylinder of the wheel brake i via the hydraulic control valve h provided in the modulator g, and the desired braking action is performed.

Further, the rotation of the wheel is detected by the rotation sensor j, and the rotation of the wheel is stopped or is about to stop based on the output of the rotation sensor j, that is, when the lock of the wheel is detected, the modulator k is controlled by the controller k. A control signal is supplied to the control valve 1 of g. Then, the air supply passage from the brake valve 2 to the air chamber of the control cylinder provided in the modulator g is closed and the exhaust passage is opened. In this way, when the internal pressure of the air chamber drops,
Since the hydraulic pressure (brake hydraulic pressure) supplied to the cylinder of the wheel brake i decreases, the locking of the wheels is prevented (see Japanese Patent Publication No. 50-7236).

<Problems to be Solved by the Invention> In the conventional anti-lock brake device configured as described above, the modulator g is provided for each wheel (wheel brake), and when the brake pedal c is released, the brake booster e and the brake booster e are released. The air in the modulator g is exhausted from the brake valve d. For this,
By adopting the antilock brake device, the air consumption amount increases, and accordingly, it becomes necessary to increase the capacity of the air tank b. Therefore, when the conventional anti-lock brake device having such a structure is provided, the air tank of the normal brake device without the anti-lock brake device cannot be diverted as it is, or the capacity of the air tank is increased, and the air tank of the automobile is increased. Since the weight is increased and the operating rate of the air compressor a is increased, the power loss is increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antilock brake device for an automobile that can suppress an increase in air consumption due to the adoption of the antilock brake device.

<Means for Solving the Problems> In order to achieve the above object, in the present invention, a brake booster that generates a hydraulic pressure in response to an air pressure output from a brake valve operated by a brake pedal, and a brake booster In an anti-lock brake device for an automobile, which comprises a hydraulic control valve for controlling hydraulic pressure supplied to a wheel cylinder and a modulator having a control cylinder to which air output from the brake valve is supplied, the output from the brake valve An air supply passage that guides air to the air chamber of the control cylinder, a return passage connected in parallel to the air supply passage, and an exhaust passage that connects the air chamber to the atmosphere are formed in the housing of the modulator. Then, the wheels are locked (the state in which the wheels stop rotating or are about to stop. The same applies hereinafter).
An air supply valve that closes the air supply passage when is detected,
An exhaust valve that opens the exhaust passage when a wheel lock is detected, and the return passage that opens when the internal pressure of the air chamber is higher than a predetermined value, while the internal pressure of the air chamber becomes lower than the predetermined value. A holding valve is provided to close the return passage. Further, the check valve function of blocking the outflow from the air chamber is held by the air supply valve, and the check function of blocking the inflow to the air chamber is held by the holding valve, and then the air supply valve and the exhaust valve are held. And a holding valve is incorporated in the air supply passage, the exhaust passage, and the return passage.

<Operation> When the brake pedal is operated by depressing the brake pedal in the automobile anti-lock brake device having such a configuration, the air pressure in response to the depressing stroke is supplied from the brake valve to the air chambers of the brake booster and the modulator.
The brake booster outputs hydraulic pressure in response to the supplied air pressure, and this hydraulic pressure passes through the hydraulic control valve of the modulator to the wheel cylinder (hydraulic cylinder of the wheel brake).
The braking force is obtained because it is supplied to the.

When supplying the hydraulic pressure, when the wheels are not in the locked state, the air supply valve is opened and the exhaust valve is closed based on the output from the rotation sensor. Therefore, in this case, since the air pressure output from the brake valve is supplied to the air chamber of the modulator control cylinder via the air supply valve, the internal pressure of this air chamber becomes high and is output from the brake booster. Since the hydraulic pressure is supplied to the wheel brake as it is without being attenuated, a braking force in response to the depression operation force (stroke) of the brake pedal can be obtained.

On the other hand, when the wheels are locked when the brake is actuated, such as when traveling on a low friction road, that fact is detected (calculated) based on the output signal from the rotation sensor. Then, the air supply valve installed in the air supply passage is closed and the exhaust valve installed in the exhaust passage is opened, so that the internal pressure of the air chamber is reduced. Therefore, the hydraulic control valve of the modulator is closed to stop the increase of the hydraulic pressure of the wheel cylinder, the volume of the hydraulic chamber of the hydraulic control valve is increased, and the hydraulic pressure supplied from the brake booster to the wheel cylinder is compensated for damping. The braking force of the wheel brakes is reduced and corrected to prevent wheel locking.

After locking the wheels in this way,
Since the air supply valve is opened and the exhaust valve is closed based on the output from the rotation sensor, the internal pressure of the control cylinder rises again, and the damping correction of the hydraulic pressure supplied to the wheel cylinders is interrupted to stop the braking force. To increase. Similarly, the air supply valve and the exhaust valve are opened / closed based on the wheel rotation state, the internal pressure of the air chamber is increased / decreased, and the hydraulic pressure (brake hydraulic pressure) supplied to the wheel cylinders is increased / decreased to prevent the wheels from locking. Then gradually stop the car.

On the other hand, when the brake pedal is loosened, the air pressure output from the brake valve decreases, so the hydraulic pressure output from the brake booster decreases. Further, the internal pressure of the air chamber is high during the operation of the brake. Therefore, at the same time that the output pressure of the brake valve decreases, the holding valve provided in the return passage opens to let out the air in the air chamber.
The internal pressure of the air chamber also decreases in synchronization with the decrease in the hydraulic pressure output from the brake booster. Therefore, in the process of loosening the brake pedal, the hydraulic pressure (braking force) supplied to the wheel cylinders decreases as the output pressure of the brake booster decreases.

In this way, the internal pressure of the air chamber becomes lower than the set pressure of the holding valve, and the holding valve automatically closes to prevent the outflow of air from the air chamber (hold the pressure). Therefore, even when the brake pedal is released, the air in the control cylinder (air chamber) of the modulator is not completely discharged as in the conventional case, and the air consumption is controlled.

Further, an air supply valve and an exhaust valve, which increase / decrease the hydraulic pressure supplied from the brake booster to the wheel cylinder by increasing / decreasing the internal pressure of the holding valve and the control cylinder thus suppressing the air consumption, are installed in the modulator housing. Since the air supply passage and the exhaust passage are provided, it is possible to reduce the size and weight of the entire device and reduce the number of man-hours required for piping.

<Example> An example of the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram showing an outline of an automobile anti-lock brake device according to the present invention. An air tank 2 is connected to an air compressor 1 driven by an engine (not shown), and a brake valve 3 is connected to the air tank 2. And the air supply port of the brake booster 4 is connected. Reference numeral 5 is a brake pedal provided on the brake valve 3.

The hydraulic pressure output from the brake booster 4 is connected to the hydraulic cylinder of the wheel brake 8 (hereinafter referred to as the wheel cylinder) via the hydraulic control valve 7 of the modulator 6 so that the hydraulic pressure output from the brake booster 4 is connected to the wheel cylinder. Is supplied to the wheel brake 8 to operate it. Reference numeral 9 is an oil reservoir provided in the brake booster 4.

An air supply port of a modulator 6 is connected to the brake valve 3 via an air pipe. The modulator 6 is configured as shown in FIG. 2, and has a control cylinder 11 into which a piston 10 connected to the hydraulic control valve 7 is fitted.
An air supply passage 13 and an exhaust passage 14 are provided in a housing 12 that covers a single surface of the. Then, one end of the air supply passage 13 is connected to the air output port of the brake valve 3, and the other end of the air supply passage 13 is opened to the air chamber 15 of the control cylinder 11.
The air chamber 15 and the outside air are connected via the exhaust passage 14.

Further, an air supply valve 16 by an electromagnetic check valve is installed in the air supply passage 13, and an exhaust valve 17 by an electromagnetic check valve is also installed in the exhaust passage 14 to correspond to the rotation speed of the wheels. By connecting the air supply valve 16 and the exhaust valve 17 to the output terminal of the controller 19 to which the output of the rotation sensor 18 which outputs a signal is supplied as a control signal, the air supply valve 16 and the exhaust valve 17 are connected by this controller 19. It is designed to open and close.

Further, a return passage 20 that bypasses the air supply valve 16 is provided in the housing 12, and a holding valve 21 is interposed in the return passage 12.

The holding valve 21 includes a valve seat 22 provided in the return passage 20.
And a check valve including a valve 23 facing the valve seat 22 from the brake valve side, and a valve spring 24 for seating and holding the valve 23 on the valve seat 22.

Reference numeral 25 is a hydraulic pressure inlet of the hydraulic control valve 7, and 26 is a hydraulic pressure outlet. The hydraulic pressure inlet 25 is connected to the hydraulic pressure output port of the brake booster 4, and the hydraulic pressure output port 26 is connected to a wheel cylinder. 27 is a valve of the hydraulic control valve 7, 28
Is also a valve seat, and 29 is a plunger that passes through a passage provided in the valve seat 28 and faces the valve 27, and its end face faces the tip of a pin 30 fixed to the valve 27. Also, the plunger 29 and the piston
By connecting with 10, the valve 27 is opened / closed according to the balance between the internal pressure of the control cylinder 11 and the hydraulic pressure acting on the end face of the plunger 29, and the communication between the hydraulic pressure inlet 25 and the hydraulic pressure outlet 26 is cut off. Plunger 29 and piston 10
Decompression degree of the hydraulic pressure supplied to the wheel cylinders (correction amount) by utilizing the increase or decrease in the volume of the hydraulic chamber 31 corresponding to the movement amount of
Is adjusted to increase or decrease.

In the automobile anti-lock brake device configured as described above, when the brake pedal 3 is stepped on to open the brake valve 3, air pressure corresponding to the stepping force (stroke) of the brake pedal 5 at this time is output from the brake valve 3. To be done.

At this time, during braking in a normal state in which the wheels are not locked, the air supply valve 16 is opened and the exhaust valve 17 is closed by the inactivation signal output from the controller 19. For this reason, the air output from the brake valve 3 with the depression of the brake pedal 5 is supplied to the brake booster 4 and also to the air chamber 15 of the control cylinder 11 via the air supply valve 16.

Therefore, the internal pressure of the air chamber 15 of the control cylinder 11 rises corresponding to the output of the brake valve 3, and the force pushing the piston 10 to the left side in FIG. 2 is output from the brake booster 4 to move the plunger 29 to the right side in the figure. It is larger than the force that presses against. Then, the piston 10 and the plunger 29 move to the left of the illustrated position to move the pin 30 in the same direction, so that the valve 27 is opened and the hydraulic pressure supplied to the hydraulic pressure inlet 25 is directly output to the hydraulic pressure outlet. . Therefore, in the state where the wheels are not locked, the hydraulic pressure output from the brake booster 4 is supplied to the wheel cylinders to perform the desired braking action, as in the case of the brake device that does not include the anti-lock brake device.

On the other hand, when it is detected that the wheels are locked or locked by such braking based on the output of the rotation sensor 18, the controller 19 outputs an operation signal. Then, the air supply valve 16 is closed and the exhaust valve 17 is opened at the same time, so that the internal pressure of the air chamber 15 is reduced and the piston
The force that pushes 10 to the left in the figure decreases. For this reason, the piston 15 and the plunger 29 move to the right side in the drawing, and the pin 30
Since the push-opening of the valve 27 is interrupted by the valve 27, the valve 27 is seated on the valve seat 28, blocking the communication between the hydraulic pressure inlet 25 and the hydraulic pressure outlet 26, and increasing the volume of the hydraulic pressure chamber 31 to be supplied to the wheel cylinder. Correct the hydraulic pressure to avoid locking the wheels.

Further, when the locking of the wheels is avoided in this way, a non-operation signal is output from the controller 19, the air supply valve 16 is opened and the exhaust valve 17 is closed, so that the internal pressure of the air chamber 15 rises again, The valve 27 is opened to increase the hydraulic pressure supplied to the wheel cylinder, and thereafter, similarly, the air supply valve 16 and the exhaust valve 17 are controlled to be opened / closed to optimally control the hydraulic pressure supplied to the wheel cylinder to prevent the conventional antilock. It will perform the same lock prevention function as the braking device.

By the way, when the brake pedal 5 is loosened, the air downstream of the brake valve 3 is discharged from the brake valve 3. By the way, the air chamber 15
The output pressure of the internal pressure brake valve 3 is as high as almost the same. Therefore, when the brake pressure is reduced by the exhaust of the brake valve 3 and the differential pressure between the internal pressure of the air chamber 15 and the output pressure of the brake valve 3 becomes larger than the set pressure of the valve spring 24, the valve 23 of the holding valve 21 causes the valve 23 to open. The holding valve 21 is opened apart from the valve seat 22 against the spring 24. Therefore, if the output pressure of the brake valve 3 decreases due to the release of the brake pedal, the return passage 20
The holding valve 21 provided in the valve opens to allow the air in the air chamber 15 to flow out and reduce its internal pressure. Then, when the internal pressure of the air chamber 15 is reduced to be equal to the set pressure by the valve spring 24, the valve 23 is seated on the valve seat 22 and the air on the downstream side (the air in the air chamber 15) is contained. Therefore, the discharge amount of air (air consumption amount) generated when the brake pedal 5 is loosened is reduced. Further, once the air is trapped, the air will not be supplied to the control cylinder 11 from the next braking if the output pressure of the brake valve 3 is below a predetermined value. For this reason, there is no need to provide a large-capacity air tank as in the prior art, and moreover, an increase in the operating rate of the air compressor is suppressed, which is economical.

Further, the air supply valve 16, the exhaust valve 17 and the holding valve 24 are attached to the housing 12
Since it is incorporated in the air supply passage 13, the exhaust passage, and the return passage 20, it is possible to reduce the size and weight of the entire device and reduce the number of piping steps performed when adding the antilock brake device.

Since low-pressure air is only contained in the control cylinder 11 of the modulator 6, the exhaust valve 17 should be opened even when the wheel lock occurs while the output pressure of the brake valve 3 is low. Therefore, the operation response of the antilock brake device is not performed such that the internal pressure of the air chamber 15 can be promptly reduced.

In addition, the check valve 21 has a check function to prevent the flow into the air chamber 15.
Therefore, when the air supply valve 16 is closed due to the lock of the brake, air is not inadvertently supplied from the holding valve 21 to the intake chamber 15, so the brake lock must be avoided securely. In addition, since the air supply valve 16 has a check function that prevents the air from flowing out of the air chamber 15, air flows out from the air chamber 15 through the air supply valve 16 when the brake is released. Therefore, the pressure holding function of the holding valve 21 is not hindered.

<Effects of the Invention> As is apparent from the above invention, according to the present invention, the return passage is opened when the internal pressure of the air chamber is higher than the predetermined value, and the return passage is returned when the internal pressure of the air chamber becomes lower than the predetermined value. Since the holding valve that closes the passage is provided to contain the air in the air chamber, it is possible to suppress an increase in the air consumption amount due to the addition of the antilock brake device. Further, since the holding valve for enclosing air and the intake valve and exhaust valve for controlling the pressure of the air chamber of the modulator are incorporated in the housing of the modulator as described above, it is possible to reduce the size and weight of the entire device and reduce the number of piping steps. It can also be reduced. Since the check valve that prevents outflow from the air chamber is held by the air supply valve and the check function that blocks inflow to the air chamber is held by the holding valve, the brake lock is reliably avoided. While being able to
The function of holding the air pressure by the holding valve is not hindered.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of an automobile anti-lock brake device according to the present invention, FIG. 2 is a sectional view showing an internal structure of the modulator, and FIG. 3 is a block diagram showing an outline of a conventional example. 1 ... Air compressor, 2 ... Air tank, 3 ... Brake valve, 4 ... Brake booster, 5 ... Brake pedal, 6 ... Modulator, 7 ... Hydraulic control valve, 8 ... Wheel brake, 10 ... Piston, 11 ... … Control cylinder 12 …… Housing, 13 …… Air supply passage 14 …… Exhaust passage, 15 …… Air chamber 16 …… Air supply valve, 17 …… Exhaust valve 18 …… Rotation sensor, 19 …… Controller 20 …… Return passage, 21 …… Holding valve 22 …… Valve seat, 23 …… Valve 24 …… Valve spring, 25 …… Hydraulic inlet 26 …… Hydraulic outlet, 27 …… Valve 28 …… Valve seat, 29 …… Plunger 30 ...... Pin, 31 …… Hydraulic chamber

Claims (1)

(57) [Claims] 1. A brake valve operated by a brake pedal, a brake booster for generating a hydraulic pressure in response to an air pressure output from the brake valve, and a hydraulic pressure for controlling a hydraulic pressure supplied from the brake booster to a wheel cylinder. A control cylinder and a control cylinder to which the air output from the brake valve is supplied are provided, and the air supply passage that guides the air output from the brake valve to the air chamber of the control cylinder and the air supply passage are connected in parallel to the air supply passage. And a modulator having a housing provided with an exhaust passage for connecting the air chamber to the atmosphere, and an air supply valve provided in the air supply passage for closing the air supply passage when lock of a wheel is detected. An exhaust valve that is provided in the exhaust passage and opens the exhaust passage when a wheel lock is detected; And a pressure-responsive holding valve that opens the return passage when the internal pressure of the air chamber is higher than a predetermined value and closes the return passage when the internal pressure of the air chamber becomes lower than the predetermined value. The anti-lock function for automobiles is characterized by having a check function to prevent the outflow from the air chamber to be held in the air supply valve and a check function to prevent the inflow to the air chamber in the holding valve. Brake device.