JPH04866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a brake control device that always provides a deceleration corresponding to a brake input.

(Technical background) When the driver applies a certain amount of brake input by depressing the brake pedal, etc., the vehicle is decelerated at a deceleration corresponding to this brake input. In other words, the relationship between the brake input and the deceleration of the vehicle It is preferable for brake operation that these are always in a corresponding relationship.

(Technical issue) However, with conventional brake systems,
The above correspondence cannot be obtained due to changes in the weight of the vehicle body due to the number of passengers on board, the weight of loaded luggage, etc. In addition, in brake devices that apply braking force directly to the wheels, such as disc brakes, the friction butts themselves may vary in their own coefficient of friction, fade, water leakage from the discs during rainy weather, etc. may cause the friction butts to be affected even with a pressing force that corresponds to the brake input. Even if the brake force is pressed against the disc, 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 a, and the deceleration of the vehicle is a, then the relationship =ma holds true. Therefore, even if a braking force corresponding to the magnitude of the brake input is obtained, if the weight m of the vehicle body changes, the deceleration a corresponding to the brake input will not be obtained. Further, even if the weight m of the vehicle body is constant, the braking force corresponding to the brake input cannot be obtained for the reason described above, and therefore the deceleration a corresponding to the brake input cannot be obtained.

Furthermore, Japanese Patent Application Laid-Open No. 48-44926 discloses a brake control device configured to perform brake control by detecting brake input and vehicle deceleration, and Japanese Patent Application Laid-Open No. 49-85468 discloses The braking force generating unit is divided into a constant pressure chamber and two or more variable pressure chambers by multiple movable partitions with different effective pressure receiving areas,
The constant-pressure chambers are connected to a vacuum source, and each variable-pressure chamber is separately connected to a vacuum source or the atmosphere through a solenoid valve, and all or part of the variable-pressure chamber is connected to the atmosphere by selective operation of the solenoid valve by an electric signal. A brake control device that communicates with the chambers and generates braking force based on the differential pressure between each chamber is shown, but in the former, like a booster, it obtains a large output in response to the input and controls the brake pedal force. It is difficult to reduce the brake pedal force because the device does not use a device that can reduce the amount of pressure applied, and the latter device does not use a common system that communicates each chamber of the pressure booster with a vacuum source and an atmospheric source. The system uses two control valves for control, which makes the entire system complicated.

(Objective) The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a brake control device with a simple configuration that can reduce the brake pedal effort.

(Structure) In order to achieve the above object, the present invention includes a brake input detection sensor that detects brake pedal force, a deceleration detection sensor that detects vehicle deceleration, and a brake input sensor that is connected to a brake system and that is connected to a brake assist system. A brake force adjusting actuator having a force generating section and a control valve section compares the outputs of the two sensors and outputs the difference signal to the control valve section to control the control valve section and output the difference signal to the control valve section. control means for generating a corresponding force in a brake assisting force generating section of the brake force adjusting actuator, the brake assisting force generating section being connected to a front chamber connected to a negative pressure source and a positive pressure source or a negative pressure source. The control valve part is configured of a pressure booster having a connectable rear chamber, and the control valve section defines therein a valve chamber having three passages connected to the negative pressure source, the positive pressure source, and the rear chamber. a solenoid disposed within the valve chamber that generates magnetic force based on the differential signal; a movable shaft that responds to the magnetic force of the solenoid; a spring disposed within the valve chamber that biases the movable shaft in a predetermined direction; It has a movable shaft, a valve body and a valve seat provided in the valve chamber, and the rear chamber is opened and closed by opening and closing the three passages by moving the valve body away from and sitting on the valve seat. It is configured to be able to be set to three states: a state in which the rear chamber communicates with the negative pressure source, a state in which the rear chamber communicates with the positive pressure source, and a state in which the rear chamber is cut off from the negative pressure source and the positive pressure source. It is characterized by

(Operation) With this configuration, the actuator can accurately correct the "difference" between the brake pedal force and the corresponding deceleration that should be obtained.

(Example) The present invention will be described in detail below based on drawings showing examples thereof.

In FIG. 1 showing the first embodiment of the present invention, 1
is a brake pedal, 2 is a master cylinder, and 3 is a wheel. The mechanical external force generated by depressing the brake pedal 1 is transmitted to the master cylinder 2 via the rod 4, where brake fluid pressure is generated. Brake fluid pressure is transmitted to the brake cylinders of the wheels 3 via the brake pipe 5.

The rod 4 is provided with a brake input detection sensor 6 that detects the depression force of the brake pedal 1, and the wheel 3 is provided with a deceleration detection sensor 7 that detects this deceleration. The output from the control means 8 is inputted to the control means 8. The control means 8 includes a comparator 8a that compares inputs from both sensors 6 and 7, and a pulse oscillator 8b that receives an amplified signal from the comparator 8a and outputs a pulse signal. Also,
A brake pedal 1 is connected between the rod 4 and the master cylinder 2 in accordance with the output from the control means 8.
An actuator 9 is provided which further adds a brake assisting force to the brake input from the brake input and transmits it to the master cylinder 2.

Here, a specific example of the actuator 9 will be explained with reference to FIG. a control valve B that receives the output and controls the generation of the auxiliary force in the auxiliary force generating section A;
It consists of

The brake assisting force generating section A is substantially constituted by a tandem type air pressure booster. This tandem type air pressure booster has a housing 10 defining a sealed chamber inside, and the housing 10 is connected by a center plate 11 to an output side servo 12 (on the left side in FIG. 2) and an input side servo 13 (on the left side in FIG. 2). In Figure 2,
right side) is formed. Both servos 12 and 13 are connected to the front chambers 16 and 13 by movable bulkheads 14 and 15, respectively.
17 and rear chambers 18 and 19, the housing 1
Inside 0, there are four chambers A (front chamber 16 of the output side servo), B (rear chamber 18 of the output side servo), and C from the output side to the input side (from the left side to the right side in Figure 2).
(front chamber 17 of the input side servo) and D (rear chamber 19 of the input side servo) are formed, and the thrust of the movable recessed wall 14 caused by the pressure difference between the front chamber A16 and the rear chamber B18 of the output side servo 12 is formed. Here, the movable partition wall 15 is connected to the movable partition wall 15 via the cylindrical member 20 that is integrally fixed to the movable partition wall 15 of the input side servo 13.
The force is transmitted to the movable bulkhead 15, and is added to the thrust force of the movable bulkhead 15, which acts on the master cylinder 2 via the output rod 21 as a brake assisting force. In order to control the pressure relationships between chambers A and B, and between chambers C and D, chamber A is connected to a negative pressure generator such as an engine intake pipe (not shown) via piping 22, and between chambers B and D. D is connected to chamber B via piping 23 and 24.
and piping 22 are connected via piping 24 and piping 25 to control valve section B, which will be described below.

The control valve part B has a housing 27 defining a valve chamber 26 therein, and a pair of solenoids 28 and 29 are spaced apart from each other in the housing 27 so as to sandwich the valve chamber 26 therebetween. In the valve chamber 26,
A fixed valve seat 30 is formed, and a valve element/valve seat member 31 that is seated on and off from the fixed valve seat 30 is integrated into a rod 32 operated by a solenoid 28. 32a is a central communication port formed in the valve body/valve seat member 32. Also, solenoid 29
The rod 33, which is actuated by
A valve body 34 for opening and closing is integrated. That is, the valve body/valve seat member 31 acts as a valve body with respect to the fixed valve seat 31 and acts as a movable valve seat with respect to the valve body 34.

A first connection port 35 is opened in the valve chamber 26 on the opposite side of the fixed valve seat 30 with the valve body/valve seat member 31 as a boundary, and the first connection port 35 and the fixed valve seat 30 are connected to each other.
A second connection port 36 is opened between the
The third connection port 37 is opened on the left side of the fixed valve seat 30 in FIG. The first connection port 35 communicates with the chamber D via the piping 23,
The second connection port 36 is connected to the pipe 22 via the pipe 25, and the third connection port 37 is communicated with the chamber B via the pipe 24. In addition,
The valve body 34 (rod 33) is urged toward the valve body/valve seat member 31 by a spring 38. Furthermore, the solenoids 28 and 29 each attract and displace each rod 32 and 33 to the left in FIG. energized). Therefore, the open state (valve opening ratio) of each valve 31, 34 can be controlled, and the amount of fluid in the auxiliary force generating section A can be controlled with a force corresponding to the output difference from both sensors 6, 7. It's getting old.

Such a control valve section B has a control means 8.
It operates according to the energization state of each solenoid 28, 29 based on the above, and allows the pipes 23, 24, and 25 to take three different communication modes, as shown in FIG. That is, piping 2
A mode in which pipes 4 and 25 communicate with each other to form an outflow path to chamber B [FIG. 3A], and a mode in which pipes 23 and 24 communicate with each other to form an inflow path to chamber B [FIG. 3A]. B], and a mode in which communication between the pipes 23, 24, and 25 is cut off to form a non-communicating path [FIG. 3 C].
Since the amount of fluid in the auxiliary force generating section A can be controlled by a force corresponding to the output difference from both sensors, the rate of increase or decrease of the auxiliary force can also be controlled in the embodiments A and B of Figure 3. It has become a variable factor.

Here, the deceleration detection sensor 7 is configured such that, for example, a permanent magnet (not shown) is attached to a brake disc (not shown) of a disc brake (not shown) of the (wheel 3), and a permanent magnet (not shown) is located near the rotation trajectory of the permanent magnet. A pulse oscillator (not shown) that emits a pulse signal when the permanent magnet sweeps is arranged to detect the change in the number of pulses per unit time, that is, the disk (wheel 3).
The deceleration can be detected by measuring the degree of decrease in the number of rotations. In addition, while opening a small hole (not shown) in the disk,
A light emitting element and a light receiving element (both not shown) may be arranged to sandwich the disk, and a pulse signal may be generated when light from the light emitting element passes through a small hole and is received by the light receiving element. 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 input detection sensor 6 includes, for example,
A strain gauge may be attached to the rod 4 and the magnitude of external mechanical force as a brake input may be detected as strain on the rod 4.

Next, the operation of the above configuration will be explained with reference to FIGS. 4 and 5. Now, when the driver depresses the brake pedal 1, this depressing force is transmitted to the input piston (not shown) of the master cylinder 2 via the rod 4 and the output rod 21, and the hydraulic pressure generating chamber (not shown) in the master cylinder 2 is transmitted. (not shown),
Brake fluid pressure corresponding to the depression force is generated. This brake fluid pressure is transmitted to the wheels 3 via the brake pipe 5, and the vehicle is decelerated.

The depression force of the brake pedal 1 is detected as a brake input by a sensor 6 and inputted to the control means 8, and the deceleration is detected by the sensor 7 and inputted to the control means 8. Both sensors 6
The inputs from and 7 are compared by a comparator 8a, and the amplified signal thereof is output to a pulse oscillator 8b.

Here, the relationship between brake pedal force and deceleration is
The actuator control mode is divided into three cases: when it is in the ideal state [on the X-line in Figure 3], when the deceleration is low relative to the pedal force, and when the deceleration is high relative to the pedal force. I will explain.

(1) During phase The pulse oscillator 8b outputs an output corresponding to the phase to the control valve section B. As a result, the control valve part B becomes the state shown in FIG. 3C, and the communication with the chamber B is cut off.
The assist force remains unchanged, the brake fluid pressure remains in equilibrium, and the ideal relationship between pedal effort and deceleration continues.

(2) When in phase The pulse oscillator 8b outputs an output corresponding to the phase to the control valve section B. As a result, the control valve section B assumes the configuration shown in FIG. 3B, and air from the chamber D flows into the chamber B.

When located at point a (when the deceleration deficit is relatively small), a pulse signal is output that makes the opening ratio of each valve body 34 relatively small, and a small amount of air flows into chamber B. be done. As a result, the movable bulkhead 14 is displaced forward, and in addition to the depression force of the brake pedal 1, a slightly increased assisting force is applied to the outlet rod 21, and correction is made to increase the brake fluid pressure supplied to the wheels 3. be done.

When located at point b (when the deceleration deficit is relatively large), the valve opening ratio, the amount of air flowing into chamber B, the amount of displacement of the movable bulkhead 14, the amount of applied biasing force, and the wheel 3
The amount of increase in the brake fluid pressure supplied to the brake fluid pressure is corrected to be relatively large.

(3) When in phase, control valve section B is output from pulse oscillator 8b.
A signal is output so that the state takes the form shown in FIG. 3A, and the air in chamber B flows out to the negative pressure generating section.
As a result, contrary to the phase, the assisting force is reduced, and the brake fluid pressure supplied to the wheels 3 is corrected to be small. Note that even in this phase, the correction amount is adjusted depending on the state of deviation from the X-rays.

Therefore, no matter what the relationship between the brake pedal force and the deceleration is, it can be quickly and accurately corrected to maintain the ideal relationship.

In addition, the brake pedal force can be input through the booster and supplementary force can be added to the brake force while the brakes are being applied, making it possible to reduce the brake pedal force in order to obtain the desired braking force. Become. Furthermore, in order to perform the common control of communicating each chamber of the pressure booster with the vacuum source and the atmospheric source, one control valve part B is used as described above, so it is especially The entire device can be simplified compared to that shown in JP-A-49-85468.

FIG. 6 shows a second embodiment, and the same components as those in the previous embodiment are given the same reference numerals and their explanations will be omitted. In this embodiment, there is one solenoid valve (solenoid 29) in the control valve section B.
and rod 33), and solenoid 2
9, a variable (direct current or alternating current) current from the control means 8 is involved, and therefore the opening degree of the solenoid valve can be changed by a force corresponding to the output difference from both sensors 6 and 7. It's becoming like that. In addition, 39 is a spring as a biasing means related to the valve body/valve seat member 31, and 40 is a stopper portion formed at one end (left end) of the rod 33, and the former 39 causes the valve to move to one side (left side). Body/valve seat member 3
1 is energized, and the latter 40 restricts movement of the rod 33 to the other side (right side) beyond a predetermined value.

Since the operation of this embodiment is basically the same as that of the first embodiment, only FIGS. 7A, 7B, and 8 and FIG.

The present invention is not limited to the first and second embodiments, but includes the following modifications, for example.

(a) Brake assist force generation part B of actuator 9
Alternatively, a single pressure booster may be used.

(b) The actuator 9 may be located not in the mechanical brake system from the brake pedal force section to the master cylinder 2, but in the fluid system from the master cylinder 2 to the wheels 3.

(c) Multiple brake systems, and for each system,
The actuators 9 may be connected separately.

(d) The relationship between the front chambers 16, 17 and the rear chambers 18, 19 may be such as atmosphere-compressed air or vacuum-compressed air.

(Effects) As described above, according to the present invention, a deceleration corresponding to the brake pedal force can always be obtained, which is preferable for brake operation. In particular, since the amount of fluid in the brake assisting force generating section is controlled by a force corresponding to the difference between the pedal force and the deceleration, control accuracy is high.

Further, even if the vehicle weight changes drastically, there is no need to adjust the brake operation before and after the change, which is preferable from the standpoint of reducing driver fatigue and ensuring safety.

Since the brake pedal force can be input through the booster and a large force can be output accordingly, the brake pedal force can be reduced in order to obtain the desired braking force. Furthermore, the common control of communication between each chamber of the pressure booster and the vacuum source and atmospheric source is achieved using a single control valve, making it possible to simplify the entire device. .

[Brief explanation of drawings]

Fig. 1 is a simplified system diagram showing the first embodiment of the present invention, Fig. 2 is a concrete system diagram of Fig. 1, and Figs.
C is a diagram showing the operating state of the control valve section shown in FIG. 2, FIG. 4 is a diagram showing the relationship between brake pedal force and deceleration, and FIG. 5 is a diagram showing the correlation for the operation according to the first embodiment. Figure 6 is a detailed system diagram of main parts showing the second embodiment of the present invention, and Figures 7A to 7C are the sixth embodiment.
A diagram showing the operating state of the control valve shown in the figure,
FIG. 8 is a diagram showing the correlation for the operation according to the second embodiment. 1... Brake pedal (brake pedal force part), 3
... Wheels, 5 ... Brake piping, 6 ... Brake input detection sensor, 7 ... Deceleration detection sensor, 8 ...
...control means, 8b...pulse oscillator, 9...actuator, 28, 29...solenoid, A...
Brake auxiliary force generating section, B...control valve section.

Claims (1)

[Scope of Claims] 1. A brake input detection sensor that detects brake pedal force, a deceleration detection sensor that detects vehicle deceleration, and a brake force that is connected to a brake system and has a brake assist force generation section and a control valve section. The adjustment actuator and the outputs of the two sensors are compared, and the difference signal is outputted to the control valve section to control the control valve section and apply a force corresponding to the difference signal to the brake force adjustment actuator. A control means for causing the brake assisting force generating section to generate a pressure booster, the brake assisting force generating section having a front chamber connected to a negative pressure source and a rear chamber connectable to a positive pressure source or a negative pressure source. The control valve section includes a housing defining therein a valve chamber having three passages connected to the negative pressure source, the positive pressure source, and the rear chamber, and a housing disposed inside the valve chamber and having the differential valve. A solenoid that generates magnetic force in response to a signal, a movable shaft that responds to the magnetic force of the solenoid, a spring that is disposed within a valve chamber and biases the movable shaft in a predetermined direction, and a valve that is provided within the movable shaft and the valve chamber. and a valve seat, and by opening and closing the three passages by moving the valve body away from and sitting on the valve seat, the rear chamber is in communication with the negative pressure source, and the rear chamber is in communication with the negative pressure source. A brake control device configured to be settable to three states: a state in which the chamber communicates with the positive pressure source and a state in which the rear chamber is cut off from the negative pressure source and the positive pressure source. 2. The brake control device according to claim 1, wherein the solenoid is driven by a predetermined pulse signal according to the difference signal. 3. The brake control device according to claim 1, wherein the solenoid is driven with a predetermined variable current according to the difference signal.