JPH0536269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brake control device that can obtain a deceleration of a vehicle corresponding to a brake operation.

(Prior art) When a driver applies a certain amount of brake pedal force by depressing the brake pedal, the vehicle is decelerated by a deceleration corresponding to this brake pedal force, that is, the brake pedal force and vehicle deceleration. It is preferable for brake operation that there is always a corresponding relationship.

However, with conventional braking systems,
The above correspondence cannot be obtained due to changes in the weight of the vehicle due to the number of passengers, the size of the load, etc. In addition, in brake devices that apply braking force directly to the wheels, such as disc brakes, there are variations in the coefficient of friction (μ) of the friction parts themselves, and the μ of the disc surface itself due to adhesion of water droplets in rainy weather.
Even if the friction pad is pressed against the disc with a pressing force corresponding to the brake pedal force, the braking force applied to the disc (vehicle) changes in various ways, making it impossible to obtain the above-mentioned correspondence. .

To explain this point in more detail, if the weight of the vehicle body is m, the braking force applied to the vehicle is f, and the deceleration of the vehicle is a, then the relationship f=ma holds true.

Therefore, even if a braking force f corresponding to the magnitude of the brake pedal force is obtained, the weight m of the vehicle body
changes, the deceleration a corresponding to the brake pedal force
will not be obtained. Also, if the weight of the car body is m
Even if is constant, the deceleration a corresponding to the brake pedal force cannot be obtained due to the reason described above.

To achieve this, a tandem servo booster is used to increase the braking force by supplying atmospheric air controlled by a solenoid valve etc. to the front rear chamber, and also to release the supplied atmospheric air to the vacuum source. It is conceivable that the braking force may be reduced to obtain the deceleration a. Such a device can be used not only for maintaining a constant relationship between pedal force and deceleration as in the prior art described above, but also for easily obtaining a constant deceleration in response to a brake operation, for example. There is.

However, the reality is that no specific structure has yet been proposed for a device using the tandem servo booster described above.

(Purpose) The present invention was made in view of the above circumstances,
The purpose of this is to reduce the force required to press the brake, to obtain the desired vehicle deceleration in response to brake operation, and to ensure that even if the control valve device malfunctions for some reason, it will not interfere with vehicle operation. It is an object of the present invention to provide a brake control device that can adjust the deceleration of a vehicle over a wide range with a simple configuration. More specifically, the object of the present invention is to provide a brake control device that does not interfere with the running of a vehicle even if such a brake control device breaks down for some reason.

(Structure) In order to achieve the above object, the present invention has a hollow housing, the inside of the housing is defined by a center plate to form an output side servo and an input side servo, and the output side servo and an input side servo are divided into a front chamber and a rear chamber communicating with a vacuum source by a movable partition, and communication between the rear chamber and the front chamber of the input side servo is cut off by actuation of a brake pedal on the input side servo. A tandem servo booster is installed between the rear chamber of the output side servo, the vacuum generation source, and the rear chamber of the input side servo. a control valve device having a solenoid connected to a brake force increase/decrease signal generating mechanism that outputs a brake force increase/decrease signal to obtain a desired vehicle deceleration in response to a brake operation, the control valve device having an output A hollow housing having a first opening communicating with a rear chamber of a side servo, a second opening communicating with a vacuum generation source, and a third opening communicating with a rear chamber of an input side servo; a fixed valve seat is formed inside, a valve body/valve seat member is provided on the fixed valve seat so as to be removable and seatable, and a first valve is formed from the fixed valve seat and the valve body/valve seat member; A second rod is disposed on the valve body/valve seat member so as to be displaceable, and has a valve body that separates from and seats on the valve body/valve seat member, and receives an axial force from the solenoid in response to a brake force increase/decrease signal to the solenoid. A valve is formed, and the first valve enables communication or isolation between the first opening and the second opening, and the second valve enables communication or isolation between the first opening and the third opening. The first opening and the third opening are connected to each other so that air is supplied from the rear chamber of the input-side servo to the rear chamber of the output-side servo.

In a brake control device with such a configuration, when the valve mechanism opens, air enters the rear chamber of the input-side servo, and due to the introduction of this air, the input-side servo creates a pressure difference between the rear chamber and the front chamber. This applies a large thrust to the output rod, thereby obtaining the desired braking force with a small brake pedal force.

The control valve device has a second control valve that operates between the rear chamber of the input side servo and the rear chamber of the output side servo due to the displacement caused by the solenoid to the rod in response to a brake force increase/decrease signal.
This causes the output side servo to generate a pressure difference between the rear chamber and the front chamber, and a force (brake assisting force) acts on the output side servo to add to the thrust of the output rod by the input side servo. Vehicle deceleration can be increased.

The control valve device shuts off communication between the rear chamber of the input side servo and the rear chamber of the output side servo by operating a second valve in response to the displacement caused by the solenoid in the rod in response to a brake force increase/decrease signal, thereby increasing the output. By stopping the rise in the differential pressure between the rear chamber and the front chamber of the side servo, in other words, suppressing the force (brake assisting force) applied to the output rod by the output side servo, it is possible to maintain the same deceleration.

The control valve device communicates the rear chamber of the output side servo with the vacuum generation source by operating the first valve in response to the displacement generated in the rod by the solenoid in response to a brake force increase/decrease signal. The pressure in the chamber is lowered, the thrust force (brake assisting force) applied to the output rod by the output side servo is made relatively small, and the rear chamber of the output side servo is communicated with the vacuum generation source by operating the first and second valves. and the communication between the rear chamber of the output side servo and the rear chamber of the input side servo is cut off to adjust the deceleration and bring the deceleration of the vehicle to the ideal deceleration.

In this way, the brake assist force exerted by the output side servo of the tandem servo booster can be used as a means of correcting the "difference" between the brake pedal force and the corresponding deceleration that should be obtained, and the brake assist force exerted by the output side servo of the tandem servo booster can be used. A desired deceleration can be obtained by increasing or decreasing the brake assisting force exerted by the input side servo of the tandem servo booster through the control valve device.

In addition, as mentioned above, in order to obtain the ideal deceleration, the valve mechanism opens and the atmosphere side communicates with the rear chamber of the input side servo, creating a pressure difference between the rear chamber and front chamber of the input side servo. Under the condition that the output rod moves forward in response to thrust according to the differential pressure, the rear chamber of the output side servo can be operated as a correction means, and by setting it this way, as long as the valve mechanism does not open. , the rear chamber of the output side servo will no longer function as a correction means, and as a result, even if the control valve device fails, the output side servo will continue to operate even though the driver is not pressing the brake pedal. The risk of this happening will be avoided.

Embodiments according to the present invention will be described below based on the drawings.

(First Embodiment) In FIG. 1 schematically showing a brake control device according to the present invention, 1 is a brake pedal, 2 is a servo booster, 3 is a master cylinder, 4 is a wheel,
The mechanical external force (depression force) generated by depressing the brake pedal 1 is multiplied by the servo booster 2 and transmitted to the master cylinder 3 via the output rod, where brake fluid pressure is generated. Braking force is transmitted to the brake cylinders of the wheels 4 via the brake piping 6. In this well-known brake system, a tandem servo booster is provided as the servo booster 2, a brake pedal force detection sensor 7 is provided at the input rod 5 to detect the pedal force on the brake pedal 1, and the wheels 4 are provided to detect the deceleration of the vehicle. A deceleration detection sensor 8 is provided to detect,
Outputs from both sensors 7 and 8 are input to control means 9. The control means 9 controls the output side servo 22 of the tandem servo booster 2 so as to compare the outputs from both the sensors 7 and 8 input to the control means 9 and set the deceleration corresponding to the brake pedal force.
It has the function of controlling the Here, to explain in detail with reference to FIG. A side servo 22 (left side in FIG. 2) and an input side servo 23 (right side in FIG. 2) are formed. Both servos 22 and 23 are connected to the front chamber 26 and 23 by movable partition walls 24 and 25, respectively.
27 and rear chambers 28, 29. Inside the housing 20, there are four chambers A (front chamber 26 of the output side servo), B (front chamber 26 of the output side servo) and B ( Output side servo rear chamber 28),
C (front chamber 27 of the input side servo) and D (rear chamber 29 of the input side servo) are formed, and the thrust force of the movable partition wall 24 caused by the pressure difference between the front chamber A26 and the rear chamber B28 of the output side servo 22 is , here, the movable partition wall 25 is connected via a cylindrical member 30 integrally fixed to the movable partition wall 25 of the input side servo 23.
The force is transmitted to the movable partition wall 25, and is added to the thrust force of the movable partition wall 25 to act on the master cylinder 3 via the output rod 31 as a brake assisting force. The front chamber A26 of the output side servo 22
The pressure control between the rear chamber B28 and the rear chamber B28, that is, the control of the brake assist force by the output side servo 22 is performed by the control means 9.

The control means 9 includes a control valve device 32 and a comparison control device 3.
It is composed of 3.

The control valve device 32 has a housing 321 that defines a valve chamber in its flesh, and a pair of solenoids 322, 32 are disposed within the housing 321 so as to sandwich the valve chamber.
3 are spaced apart.

A fixed valve seat 324 is formed in the housing 321, and a valve body/valve seat member 325 that is seated on and off from the fixed valve seat 324 is disposed so as to be displaceable in the left and right direction in FIG. 324 and the valve body/valve seat member 325 form the first valve X. The central communication port of this valve body/valve seat member 325 is connected to the solenoid 32.
2, 323, an actuating rod 326 which is displaced in the left-right direction in FIG. A valve body portion 327 that opens and closes the central communication port of the seat member 325 is provided, and this valve body portion 32
7 and a valve body/valve seat member 325 form a second valve Y. The valve body/valve seat member 325 is the fixed valve seat 32
4 as a valve body, that is, the first valve X as a valve body, the valve body portion 327 as a movable valve seat, and the second valve Y as a movable valve seat, The valve body/valve seat member 325 is biased toward the fixed valve seat 324 by the first spring 328, and the valve body portion 327 (actuating rod 32
6) is urged toward the valve body/valve seat member 325 by the second spring 329, and the urging force F ₁ of the first spring 328 is larger than the urging force F ₂ of the second spring 329 (F ₁ > F ₂ ).

The housing 321 has a first opening 331 and a second opening 331 through which communication within the valve chamber is opened and closed by the first valve X formed by a fixed valve seat 324 and a valve element/valve seat member 325.
an opening 332 is bored, and this first opening 3
31, a valve body/valve seat member 325, and a valve body portion 327
(actuation rod 326)
and a third opening 333 through which communication within the valve chamber is opened and closed.
is drilled.

The first opening 331 is connected to the rear chamber B28 of the output side servo 22 via a pipe 334, and the second opening 332 is connected to a vacuum generation source such as an engine intake pipe (not shown) via a pipe 335. The third opening 333 is connected to the input side servo 23 via piping 336.
It is connected to the rear chamber D29.

Therefore, the rear chamber B28 of the output side servo 22
is connected to the vacuum generation source via the first valve X, and is also connected to the rear chamber D29 of the input side servo 23 via the second valve Y.

In the control valve device 32 configured in this way, the valves X and Y are opened and closed by turning ON and OFF the solenoids 322 and 323, and the rear chamber B28 of the output side servo 22 and the rear chamber of the input side servo 23 are controlled. D29
and the vacuum generation source as appropriate. This state will be explained with reference to FIG. 3. In FIG. 3, A shows a state in which the solenoid 322 on the left side of the figure is OFF and the solenoid 323 on the right side is ON.
By energizing the right solenoid 323, the actuating rod 326 is suctioned and displaced to the right stroke end.
The first valve X is open and the second valve Y is closed. By opening this first valve X, the first opening 331 and the second
The opening 332 of the opening 332 communicates with the rear chamber B28 of the output side servo 22 and the vacuum generation source.
The communication between the third opening 333 and the chamber B2 is cut off.
8 and the rear chamber D29 of the input side servo 23 will be cut off.

In Fig. 3B, the solenoid 322 on the left side of the figure is
ON, and the right side 323 is OFF, and by suction displacement of the actuating rod 326 to the left stroke end, the first valve X is closed and the second valve Y is opened. When the first valve X is closed, communication between the chamber B28 and the vacuum source is cut off, while when the second valve Y is opened, the chamber B28 and the chamber D29 are communicated with each other.

In Fig. 3 C, both solenoids 322 and 323 are connected together.
Indicates ON or OFF status. In this state, the actuating rod 326 is connected to the spring 328,
329 and is displaced by the biasing force of the first spring 32
Since the biasing force F ₁ of the second spring 329 is greater than the biasing force F ₂ of the second spring 329 (F ₁ >F ₂ ), both valves X,
Both Y are closed. By closing both valves X and Y, communication between the rear chamber B28 of the output side servo 22 and the rear chamber D29 of the input side servo 23 and the vacuum generation source is cut off.

The solenoids 322 and 323 are turned on and off according to the output from the comparison control device 33, and the conditions are as follows. That is, if the actual deceleration is greater than the deceleration that should be obtained (ideal deceleration) with respect to the brake pedal force, the state shown in Fig. 3A, that is, the left solenoid 322 is turned OFF and the right solenoid 323 is turned ON, If the actual deceleration is smaller than the ideal deceleration, the state shown in Figure 3B, that is, the left solenoid 322 is
When the actual deceleration reaches the ideal deceleration, the solenoid 322 and the right side 323 are turned on, and when the actual deceleration reaches the ideal deceleration, the state shown in FIG. The comparison control device 33 compares the inputs from both the sensors 7 and 8 to adjust the solenoid 322,
Output to 323.

Here, the deceleration detection sensor 8 is, for example, a first
A permanent magnet (not shown) is attached to the brake disc of the disc brake of the wheel 4 shown in the figure, and a pulse oscillator (not shown) is located near the rotation locus of the permanent magnet and emits a pulse signal when the permanent magnet passes. ), and the deceleration can be detected by measuring the change in the number of pulses per unit time, that is, the degree of decrease in the rotational speed of the disk (wheels 4). In addition, while a small hole (not shown) is opened in the disk, a light emitting element and a light receiving element (both not shown) are arranged with the disk in between, so that light from the light emitting element passes through the small hole and is received by the light receiving element. A pulse signal may be generated when the Furthermore, the deceleration can be determined by detecting the amount of relative displacement between the sprung weight member and the unsprung weight member of the vehicle in the traveling direction.

Further, the brake pedal force detection sensor 7 includes, for example,
A strain gauge may be attached to the rod 5, and the magnitude of the external mechanical force as the brake pedal force may be detected as the strain on the rod 5.

In this embodiment, the above-mentioned brake pedal force detection sensor 7, deceleration detection sensor 8 and comparison control device 33 are used.
constitutes the brake force increase/decrease signal generation mechanism.

The operation of the brake control device configured as described above will be explained.

Now, when the driver depresses the brake pedal 1 and the rod 5 moves forward, a well-known valve mechanism Z is activated, and communication between the rear chamber D29 of the input side servo 23 and the front chamber C27 communicating with the vacuum source is cut off. At the same time, the atmosphere enters the rear chamber D29 of the input side servo 23. By introducing atmospheric air into the chamber D29, the input side servo 23 generates a pressure difference between the chambers C and D, and a brake assisting force shown by _S1 in FIG. 4 is generated. This brake assisting force _S1 is applied to the output rod 3 along with the pedal force.
1 to the master cylinder 3, and a brake fluid pressure corresponding to the resultant force of the pedal force and the brake assisting force _S1 of the input side servo 23 is generated in the master cylinder 3. This brake fluid pressure applies braking force to the wheels 4, and the vehicle is decelerated.

The pedal force on the brake pedal 1 is detected by the brake pedal force detection sensor 7 and the comparison control device 33 detects the pedal force on the brake pedal 1.
The deceleration is detected by the deceleration detection sensor 8 and input to the comparison control device 33.
The inputs from both sensors 7 and 8 are compared by the comparison control device 33, and if it is determined that the deceleration is smaller than the ideal deceleration, a corresponding output is sent to the control valve device 32. Output. As a result, the control valve device 32 is in the state shown in FIG. 3B, and the rear chamber B28 of the output side servo 22 communicates with the rear chamber D29 of the input side servo 23, so that the atmosphere enters the chamber B28. By introducing atmospheric air into the rear chamber B28 of the output side servo 22, the output side servo 22 generates a pressure difference between chambers A and B, and a brake assisting force shown by _S2 in FIG. 4 is generated. Become. This causes the brake assist force to
S ₂ additionally acts on the master cylinder 3 in addition to the pedal force and the brake assisting force S ₁ to increase the brake fluid pressure. When the deceleration increases and the comparison control device 33 determines that the deceleration is at the ideal deceleration, the control valve device 3 outputs a corresponding output.
Output for 2. As a result, the control valve device 32
becomes the state shown in FIG. 3C, and communication between chambers B and D is cut off. As a result, the auxiliary force _S2 stops increasing, so the brake fluid pressure stops increasing, and the deceleration is maintained as it is. On the other hand, if the comparison control device 33 determines that the deceleration is greater than the ideal deceleration, a corresponding output is output to the control valve device 32. As a result, the control valve device 32 enters the state shown in FIG. 3A, the chamber B communicates with the vacuum source, the assisting force _S2 decreases, and the brake fluid pressure decreases. When the brake fluid pressure decreases in this way, the deceleration decreases rapidly, but when the deceleration reaches the ideal deceleration, the state shown in Fig. 3 (c) described above occurs, the reduction in the assisting force S ₂ stops, and the deceleration decreases. The ideal deceleration will be maintained.

In this way, the output side servo 22 is operated as a deceleration adjusting means via the control means 9 as appropriate. The output side servo 22 as this correction means connects the air introduction source to the input side servo 23.
Since the rear chamber D29 is used, the input side servo 23
It will operate with the precondition that it is operating.

FIGS. 5 and 6 show second and third embodiments of the present invention, and the same components as those in the previous embodiments are given the same reference numerals and their explanations will be omitted.

In FIG. 5 showing the second embodiment, in the tandem servo booster 2, the output rod 31 penetrating the movable bulkhead 24 of the output side servo 22 is directed from the output side to the input side (from the right side to the left side in the fifth center). , a small diameter portion 34 and a large diameter portion 35, the large diameter portion 35 slidably passing through the movable partition wall 24, and the movable partition wall 24 at the output side end of the large diameter portion 35. A flange 36 that engages with the flange 36 is fixedly provided. As a modification thereof, in the third embodiment shown in FIG. 6, the output rod 31 has a small diameter portion 34 and a large diameter portion 35 from the output side to the input side.
The rod has a different diameter, and the large diameter portion 3
A cylindrical body 37 through which the output rod 31 passes is fixed to the movable bulkhead 24, and the tip of the cylindrical body 37 is made to protrude toward the output side, so that the tip serves as a master cylinder (not shown). It is configured to engage. Since the second and third embodiments are configured in this way, the output side servo 22 can be activated and stopped as the above-mentioned correction means without interfering with the operation of the input side servo 23.

(Effects) As described above, the present invention makes it possible to obtain a desired vehicle deceleration corresponding to a brake operation by using the brake assisting force by the output side servo as a correction means, and also to prevent failure of the control valve device. Even if this is the case, the operation of the output side servo as a correction means is based on the operation of the input side servo, so the output side servo alone will not operate alone, and there is a risk of dangerous overbraking, locking, etc. It is highly safe.

Furthermore, the braking assisting force exerted by the input side servo of the tandem servo booster exerted when the brake pedal is depressed is increased or decreased by the braking assisting force exerted by the output side servo via the control valve device as described above. Since the deceleration can be adjusted over a wide range, and this adjustment of the vehicle deceleration over a wide range is achieved by using a control valve device that integrally includes the first and second valves, the overall system This eliminates the need to complicate the configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic system diagram showing the brake control device of the present invention, FIG. 2 is a specific system diagram of the brake control device of the first embodiment, and FIGS. 3A to 3C are the control systems shown in FIG. 4 is a characteristic diagram of the brake assisting force of the tandem servo booster shown in FIG. 2, FIG. 5 is a system diagram of the brake control device of the second embodiment, and FIG. 6 is a diagram showing the operating state of the valve device. FIG. 3 is a detailed diagram of main parts of a brake control device according to a third embodiment. DESCRIPTION OF SYMBOLS 1... Brake pedal, 2... Tandem servo booster, 3... Master cylinder, 4... Rod, 7... Pedal force detection sensor, 8... Deceleration detection sensor, 9... Control means, 22... Output side The servo,
23... Input side servo, B, 28... Rear chamber of output side servo, D, 29... Rear chamber of input side servo, 32... Control valve device, 33... Comparison control device, X... First valve, Y... second valve.

Claims (1)

[Claims] 1. The housing has a hollow housing, the inside of the housing is defined by a center plate to form an output side servo and an input side servo, and each of the output side servo and input side servo is connected to a vacuum by a movable partition wall. A front chamber and a rear chamber that communicate with the source are defined, and when a brake pedal is applied to the input servo, communication between the rear chamber and the front chamber of the input side servo is cut off, and communication between the rear chamber of the input side servo and the atmosphere side is separated. A tandem servo booster equipped with a valve mechanism that can communicate with a control valve device having a solenoid connected to a brake force increase/decrease signal generation mechanism that outputs a brake force increase/decrease signal so as to obtain a brake force increase/decrease signal, the control valve device having a first control valve device communicating with a rear chamber of the output side servo. a hollow housing having an opening, a second opening communicating with the vacuum source, and a third opening communicating with the rear chamber of the input side servo; a fixed valve seat is formed inside the housing; A valve in which a valve body/valve seat member is provided on the valve seat so as to be separable from and seated on, a first valve is formed from the fixed valve seat and the valve body/valve seat member, and the valve body/valve seat member is separated from and seated on the valve seat. A rod having a body and receiving an axial force from the solenoid in response to a brake force increase/decrease signal to the solenoid is movably disposed on the valve body/valve seat member to form a second valve, and the second valve is formed by the first valve. The first opening and the second opening can be communicated or blocked, and the first opening and the third opening can be communicated or blocked by a second valve, and the first opening and the third opening are connected to each other. A brake control device configured to supply air from the rear chamber of the input side servo to the rear chamber of the output side servo through communication with the brake control device.