JPH08207732A - Braking force control device - Google Patents

Abstract

PURPOSE: To provide a braking force control device provided with an auxiliary function for covering the shortage of the operating force at the time of braking in case of danger. CONSTITUTION: The braking force control device is provided with wheel brakes 17, 18, 19, 20 communicated with a master cylinder 3, which generates the brake hydraulics with the operation of a brake pedal 1, through a hydraulics passage 5 so as to be operated by the brake hydraulics, a variable capacity actuator 30, of which one end is communicated with the master cylinder 3 and of which the other end is communicated with the wheel brake, and a control device 21. The hydraulics passage 5 for connecting the master cylinder 3 and the variable capacity actuator 30 is formed with an orifice 14, and a differential pressure sensor 3 is provided in parallel with the variable capacity actuator 30. With the quick operation of a brake pedal 1, when the hydraulics of the master cylinder 3 side quickly rises due to the resistance of the orifice 14, the differential pressure sensor 13 senses a rise of pressure, and operates the variable capacity actuator 30 so as to instantaneously gives the hydraulics to the wheel brakes 17, 18 for operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking force control device.

[0002]

2. Description of the Related Art If an ordinary driver is nearing danger, there is no big problem in the reaction speed until the start of braking, but hesitate to apply strong pedaling force at once, or if you want to step on it Based on the recognition that a situation occurs where it cannot actually be performed, a braking force control device having a function of covering insufficient pedaling force or the like at the time of braking at the time of danger is a car graphic 1
It is introduced on page 155 of the December 994 issue. This braking force control device includes a vacuum type brake booster arranged between a brake pedal, which is a brake operating member, and a master cylinder, a potentiometer for detecting the stroke of the power piston, and a solenoid valve for fully operating the brake booster at a stroke. When the stroke speed of the power piston exceeds a predetermined value (300 mm / sec at the brake pedal speed), the brake booster is fully actuated at once to cover the insufficient pedaling force, and is based on the antilock brake system.

Various braking force control devices are known in the anti-lock brake system. When a braking operation is not performed in order to prevent the drive wheels from idling when the vehicle starts or accelerates. Japanese Patent Laid-Open No. 3-52 discloses a structure in which brake fluid pressure can be applied to a wheel brake.
No. 70 publication. This braking force control device is shown in FIG.

In FIG. 5, 200 is a brake pedal 2.
A master cylinder that generates brake fluid pressure by depressing 01, 202 is a wheel brake that receives brake fluid pressure to brake the wheels, and 203 is a variable volume actuator that changes the volume of a pressure control chamber (not shown) that communicates with the wheel brake. Indicates.

Master cylinder 200 and wheel brake 20
2 is communicated with a hydraulic pressure path 204, and normally closed first and second solenoid valves 205 and 206 are arranged in series on the hydraulic pressure path 204.

Further, a first one-way valve 207 is arranged in parallel with the first solenoid valve 205, and the first one-way valve 207 is arranged from the downstream side (wheel brake 202 side) of the first solenoid valve 205. Only the flow to the upstream side (master cylinder 200 side) is permitted. Also, the second
Second one-way valve 2 in parallel with solenoid valve 206
08 is provided, and the second one-way valve 208 permits only the flow from the upstream side to the downstream side of the second solenoid valve 206.

The variable volume actuator 203 changes the volume of the pressure control chamber provided therein by driving a motor 203a. Hydraulic path 204, first solenoid valve 205, second solenoid valve 206
The first one-way valve 207, the second one-way valve 208, and the volume variable actuator 203 constitute a hydraulic pressure control actuator.

On the other hand, since the pressure control chamber communicates with the wheel brakes, the first solenoid valve 20 is operated when the brake pedal 201 is depressed and the brake fluid pressure is applied from the master cylinder 200 to the wheel brakes.
5 is shut off to seal the wheel brake and the pressure control chamber,
Moreover, by increasing or decreasing the volume of the pressure control chamber, it is possible to increase or decrease the brake fluid pressure of the wheel brakes to control the braking force. Even when the brake pedal 201 is not stepped on, the second solenoid valve 206 is closed to seal the wheel brake and the pressure control chamber, and the volume of the pressure control chamber is increased / decreased. The braking force can be controlled by increasing or decreasing.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, Car Graphik, December 1994, page 155, has an auxiliary function of covering insufficient pedaling force during braking when the above-mentioned danger is approaching. The braking force control device requires a large brake booster in order to generate a predetermined deceleration, and further,
Since the potentiometer is a mechanism that is built into the brake booster, the potentiometer and brake booster body can be attached and the sealability can be secured.Because the potentiometer comes out in a protruding state from the brake booster body, problems such as damage during mounting can occur. is there.

Further, the braking force control device disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-5270 discloses a braking force having functions of a normal brake, an antilock brake system (ABS), and a traction control (TRC). It is a control device and does not have an auxiliary function such as covering an insufficient pedaling force at the time of braking when the danger is at hand.

The present invention is a braking force control device provided with a hydraulic pressure control actuator capable of increasing / decreasing the brake fluid pressure of a wheel brake during brake operation and applying the brake fluid pressure to the wheel brake even during non-brake operation. It is a technical object of the invention to provide a braking force control device having an auxiliary function of covering an insufficient pedaling force or the like at the time of braking when a danger is about to occur.

[0012]

A braking force control apparatus according to the present invention includes a master cylinder for generating a brake fluid pressure by operating a brake operating member, and the brake fluid pressure communicating with the master cylinder via a fluid pressure path. A wheel brake that operates in response to the above-mentioned operation, and a hydraulic fluid for controlling the brake fluid pressure of the wheel brake during operation of the brake operating member and for applying brake fluid pressure to the wheel brake when the brake operating member is not operated. In a braking force control device comprising a hydraulic control actuator arranged in a pressure path and a control means for controlling the operation of the hydraulic control actuator, the master cylinder and the master cylinder when the brake operating member is suddenly operated. A hydraulic pressure control actuator for generating a brake hydraulic pressure difference of a predetermined value or more with the wheel brake; An orifice is installed in the hydraulic pressure path between the master cylinder and the master cylinder, and it is detected that a brake hydraulic pressure difference of the predetermined value or more is generated between the master cylinder and the wheel brake, and the predetermined signal is sent to the control means. Brake fluid pressure difference detecting means for inputting to the wheel brake is provided, and the control means operates the fluid pressure control actuator in response to a predetermined signal from the brake fluid pressure difference detecting means to apply brake fluid pressure to the wheel brakes. It is configured.

The size of the orifice is set so as not to be a resistance to the flow of the brake fluid during a normal brake operation.

[0014]

In the braking force control device of the present invention, during braking (a stepping-up of a brake with a high pressure-increasing speed) when a danger is about to occur, the resistance of the orifice causes a predetermined value or more between the master cylinder and the wheel brake. A brake fluid pressure difference occurs, which is detected by the brake fluid pressure difference detection means and a predetermined signal is input to the control means, and the control means operates the brake fluid pressure control actuator to apply the brake fluid pressure to the wheel brakes. Cover the pedal effort.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Embodiment 1) FIG. 1 is a brake hydraulic circuit diagram provided with a braking force control device according to the present invention.

In FIG. 1, the operating force of the brake pedal 1 is boosted by the brake booster 2 to operate the master cylinder 3 to generate brake hydraulic pressure. Reference numeral 4 is a reservoir tank, and 1a is a pedal switch.

Each wheel FR, FL, R by brake fluid pressure
Wheel brakes 17, 18, 19, 2 for braking R, RL
0 communicates with the master cylinder 3 via the hydraulic pressure path 5, and on the hydraulic pressure path 5, a variable volume actuator 30 for changing the volume of the pressure control chamber 36 (FIG. 2) by the motor 31 is normally provided. Open solenoid valves 6, 7, 8,
9 are provided. In this embodiment, the front wheels FR,
Variable volume actuator 3 for controlling each wheel of FL
One variable volume actuator 30 is provided in order to control each of the zero wheels and the rear wheels RR and RL that are the driving wheels.

Further, a bypass passage 11 is provided in parallel with the variable volume actuator 30 in the hydraulic pressure passage 5 on the front wheel side, and a normally closed solenoid valve 12 is arranged on the bypass passage 11. Further, a differential pressure sensor 13 that is turned on when the brake fluid pressure difference between the master cylinder 3 and the wheel brakes 17 and 18 is a predetermined value or more is provided.

An orifice 14 is provided between the variable volume actuator 30 and the master cylinder 3 in the hydraulic pressure passage 5 on the front wheel side.
Is provided.

The orifice 14 does not act as a resistance to the flow of the brake fluid during normal brake operation, and the resistance acts only on the brake fluid pressure generated from the master cylinder 3 due to the sudden depression of the brake pedal 1. It is a thing.

On the other hand, in the hydraulic pressure passage 5 on the rear wheel side, a bypass passage 11 is provided in parallel with the variable volume actuator 30, and a normally closed solenoid valve 15 is arranged on the bypass passage 11. .

A well-known proportioning valve 16 is arranged between the variable volume actuator 30 and the wheel brakes 19 and 20 in the hydraulic pressure passage 5 on the rear wheel side.

The hydraulic pressure path 5 on the front wheel side, the solenoid valves 6, 7, 12 and the variable volume actuator 30 on the front wheel side.
The front wheel side hydraulic pressure control actuator is composed of
The hydraulic path 5 on the rear wheel side and the solenoid valves 8, 9, 15
The proportioning valve 16 and the rear wheel side variable volume actuator 30 constitute a rear wheel side hydraulic pressure control actuator.

Solenoid valves 6, 7, 8, 9, 12,
The electronic control unit 21 controls the motor 15 and the motor 31 of the variable volume actuator 30. This electronic control unit 2
1, the output signal of the pedal switch 1a, the differential pressure sensor 1
In addition to the output signal of 3, the output signals of various sensors such as a wheel speed sensor that detects the rotation speed of each wheel and a sensor that detects an obstacle in front of the vehicle are input. Furthermore, when the solenoids 6, 7, 8, 9 are opened and closed for pressure increase / decrease in association with the start of the motor 31 of the variable volume actuator 30, the motor 3
Since there is a slight time lag before the brake fluid pressure actually increases or decreases by the variable volume actuator 30 after the start of No. 1, when the solenoids 6, 7, 8, 9 are opened and closed and the brake fluid pressure actually increases or decreases. To synchronize with
The opening / closing timing of the solenoids 6, 7, 8 and 9 is intentionally delayed from the operation timing of the motor 31 by the electronic control unit 21.

Further, the starting of the motor 31 and the solenoid 6,
The intentional delay of the opening / closing timing of 7, 8 and 9 is controlled by the electronic control unit 21 by patterning the increase / decrease of one wheel and the increase / decrease of two wheels. As a pattern at the time of increasing / decreasing the pressure of the two wheels, one solenoid opens and closes with a certain delay after the first start of the motor 31, and after the increase / decrease of pressure has a certain delay with respect to the second start of the motor 31. The other solenoid opens and closes to control each wheel to finish increasing and decreasing pressure.

Next, the variable volume actuator 30 will be described with reference to FIGS. 2 and 3. 2 is a sectional view of the variable volume actuator 30, and FIG. 3 is an enlarged view of a part of FIG.

2 and 3, the variable volume actuator 30 includes a housing 32, a plunger 33 slidable in the housing 32, a motor 31 for driving the plunger 33, and first and second valves 34, 35. It has and. The housing 32 has a stepped cylinder hole 32a.
And a plunger 33 is slidably arranged in the cylinder hole 32a in the axial direction.
The cylinder hole 32a forms a peripheral wall of the pressure control chamber 36.

The plunger 33 comprises a first plunger 33a on the outer peripheral side and a second plunger 33b on the inner peripheral side. The first plunger 33a has a seal cup 3 on the outer periphery.
7, the cylinder hole 32a is slidably arranged,
It is always urged downward (in FIG. 2) by the spring 38, and is also engaged with the break 32a 'of the cylinder hole 32a or the step 33b' of the second plunger 33b. As can be seen from FIG. 2, the second plunger 33b has a large diameter portion, a medium diameter portion, and a small diameter portion.
2a is slid, and the middle diameter part is provided with the seal cup 39 on the outer periphery and slides on the inner peripheral wall of the first plunger 33a. The small diameter portion is provided with a locking member 40 on the outer periphery and holds the valve element 34a of the first valve 34. Further, the second plunger 33b
Has its lower end held by the nut 41 and moves up and down as the nut 41 moves up and down (in FIG. 2).

The nut 41 meshes with a screw member 43 that rotates integrally with the first wheel gear 42, and moves up and down as the screw member 43 rotates. The first wheel gear 42 meshes with a second wheel gear 44 fixed to the output shaft 31a of the motor 31, and the rotational drive of the motor 31 is performed by the second wheel gear 44 and the first wheel gear 4
2, transmitted to the nut 41 via the screw member 43,
The plunger 33b is moved up and down (in FIG. 2).

The valve body 34a of the first valve 34 has a valve seat 34
The elastic member 34a 'that abuts the elastic member 34b and the metallic member 34a''that holds the elastic member 34a', and the locking member 4 positioned by the spring 45 in the small diameter portion of the second plunger 33b.
It is biased towards 0.

The second valve 35 includes a ball valve body 35a biased by a spring 46 toward a valve seat 35b,
The valve seat 35b has an inverted truncated cone shape.

Next, the operation of this embodiment will be described.

When the vehicle is running, the plunger 33 is in the initial position,
The solenoid valves 6, 7, 8 and 9 are open, and the solenoid valves 12 and 15 are closed. Then, when the electronic control unit 21 determines that it is necessary to decelerate the vehicle through a sensor that detects the following distance from the vehicle in front, the vehicle speed, the drowsiness of the driving vehicle, obstacles in the front, etc., the front wheel side volume variable actuator 30 The motor 31 is driven to rotate the plunger 33 in the forward direction so as to move upward. As a result, the first and second plungers 33a and 33b are moved upward, the first valve 34 shuts off the hydraulic passage 5, and the pressure control chamber 36 and the wheel brakes 17 and 18 are closed.
And are sealed. Then, the first and second plungers 33
By further moving a and 33b, the pressure control chamber 36
, The pressure increases, and the braking force is applied to the front wheels.

At this time, when the driver depresses the brake pedal 1 and the brake fluid pressure generated from the master cylinder 3 overcomes the urging force of the spring 45 and the brake fluid pressure in the pressure control chamber 36, the first valve 34 Is open to fit the driver's feeling.

When the driver depresses the brake pedal 1 by recognizing that the vehicle no longer needs to decelerate, the wheel brake 17 is separated between the hydraulic pressure on the master Linda 3 side and the hydraulic pressure on the wheel brakes 17 and 18. , The hydraulic pressure on the 18 side becomes higher,
The hydraulic pressure difference between the master cylinder 3 side and the wheel brakes 17 and 18 side becomes a predetermined value or more. As a result, the differential pressure sensor 13 is turned on, the solenoid 12 is operated, the master Linda 3 and the wheel brakes 17 and 18 are made to communicate with each other, and the hydraulic pressure on the master Linda 3 side and the hydraulic pressure on the wheel brakes 17 and 18 side become the same. The brake fluid on the side of the wheel brakes 17 and 18 is controlled to be discharged to the master cylinder 3 until the pressure is reached. Therefore, the braking force of the wheel brakes 17 and 18 is reduced. Brake pedal 1
When is released, the front wheel side volume variable actuator 30 is returned to the initial position.

On the other hand, when the driver depresses the brake pedal 1 to obtain the braking force (during normal braking), brake fluid pressure is generated from the master cylinder 3 and each wheel brake 1
7, 18, 19, 20 are exerted, and a braking force is generated.

For example, when the vehicle runs on a low μ road (snow road, icy road, etc.), an excessive braking force is applied to the front right wheel, and the electronic control unit 21 is operated.
Detects that the front right wheel is locked, the electronic control unit 21
Operates the solenoid 7 to disconnect the front left wheel brake 18 from the variable volume actuator 30, drive the motor 31 of the variable volume actuator 30 on the front wheel side, and reverse the plunger 33 to move it downward. As a result, the second plunger 33b moves downward, the second valve 35 shuts off the hydraulic passage 5, and the pressure control chamber 36 and the wheel brake 17 are sealed. Then, when the second plunger 33b is further moved downward, the volume in the pressure control chamber 36 is increased and the pressure is decreased, the braking force exerted on the front right wheel is reduced, and the front right wheel is restored again. It is restrained to grip the road surface. In this way, the brake fluid pressure of the front left wheel brake 18 is maintained while the brake fluid of the front right wheel brake 17 is being reduced.

When the brake fluid pressure of the front right wheel brake 17 has been reduced, the solenoid 6 is operated by the electronic control unit 21 to increase the braking force of the front left wheel that is not in the lock tendency, and the front wheel side volume is increased. The motor 31 of the variable actuator 30 is driven to rotate the plunger 33b forward so as to move upward. As a result, the second plunger 33
b moves upward, the volume of the pressure control chamber 36 decreases, the pressure rises, the solenoid 7 is deactivated by the electronic control unit 21, and the braking force is applied to the front left wheel.

As described above, the motor 31 of the front wheel side volume variable actuator 30 is driven to increase in order to increase the braking force of the front left wheel which is not in the lock tendency after the brake fluid pressure of the front right wheel brake 17 has been reduced. Although the pressure is applied, if the driving of the motor 31 and the opening timing of the solenoid 7 are the same, the front left wheel brake 18 side of the front left wheel brake 18 side and the front wheel side volume variable actuator 30 side via the solenoid 7 is closer. Due to the high pressure, the pressure is temporarily reduced. However, in this embodiment, the motor 3
Since the opening timing of the solenoid 7 is intentionally delayed between the driving of No. 1 and the opening timing of the solenoid 7, temporary decompression is reduced.

On the other hand, when the driver recognizes that the vehicle deceleration is no longer necessary and releases the brake pedal 1, the brake fluid returns to the master cylinder 3 so that the second valve 35 is released.
The pressure difference between the master cylinder 3 side and the wheel brake side increases. When this pressure difference overcomes the biasing force of the spring 46, the second valve 35 opens and the braking force is reduced.

Further, when the vehicle starts, when the electronic control unit 21 detects that an excessive driving force is applied to the wheels and the right wheel behind the driving wheels is slipping on the road surface, the solenoid 9 is actuated to activate the wheel brake 20 and the rear wheel. The communication with the wheel side volume variable actuator 30 is cut off, the motor 31 of the rear wheel side volume variable actuator 30 is driven, and the plunger 33 is rotated in the forward direction so as to move upward. As a result, the first and second plungers 33a and 33b move upward, the first valve 34 shuts off the hydraulic passage 5, and the pressure control chamber 36 and the wheel brake 19 are sealed. Then, the first and second plungers 33a, 3
By further moving 3b upward, the volume of the pressure control chamber 36 decreases and the pressure rises, and braking force is applied to the rear right wheel to grip the rear right wheel on the road surface and effectively accelerate the wheel. You can

When the driver abruptly depresses the brake pedal 1 at the risk of danger, the hydraulic pressure on the master cylinder 3 side and the hydraulic pressure on the wheel brakes 17 and 18 side via the orifices 14 are affected by the orifice resistance. Master cylinder 3
The hydraulic pressure on the side suddenly becomes high, and the hydraulic pressure difference between the master cylinder 3 side and the wheel brakes 17 and 18 side becomes a predetermined value or more. As a result, the differential pressure sensor 13 is turned on, and the electronic control unit 21 drives the motor 31 of the front wheel side volume variable actuator 30 to rotate the plunger 33 in the forward direction to move it upward. As a result, the first and second plungers 33a, 3a, 3
3b moves upward, the first valve 34 shuts off the hydraulic path 5,
The pressure control chamber 36 and the wheel brakes 17 and 18 are sealed. Then, as the first and second plungers 33a and 33b move further upward, the volume of the pressure control chamber 36 decreases and the pressure rises, and the braking force is applied to the front wheels. or,
Further, when the brake pedal 1 is further depressed, the brake hydraulic pressure generated from the master cylinder 3 is urged by the spring 45 and the pressure control chamber 3 in the front wheel hydraulic pressure path 5.
When the brake fluid pressure in 6 is overcome, the first valve 34 is opened and the wheel brakes 17 and 18 are exerted, and in the rear wheel side fluid pressure path 5, the wheel brakes 19 and 20 are exerted to generate a braking force.

On the other hand, if the brake pedal 1 is released by recognizing that the driving vehicle no longer needs to decelerate the vehicle, the hydraulic pressure on the master Linda 3 side and the hydraulic pressure on the wheel brakes 17 and 18 cause the wheel The hydraulic pressure on the brakes 17 and 18 side becomes higher, and the hydraulic pressure difference between the master cylinder 3 side and the wheel brakes 17 and 18 becomes a predetermined value or more. As a result, the differential pressure sensor 13 is turned on, the solenoid 12 is operated, the master Linda 3 and the wheel brakes 17 and 18 are made to communicate with each other, and the hydraulic pressure on the master Linda 3 side and the hydraulic pressure on the wheel brakes 17 and 18 side become the same. The brake fluid on the side of the wheel brakes 17 and 18 is controlled to be discharged to the master cylinder 3 until the pressure is reached. Therefore, the braking force of the wheel brakes 17 and 18 is reduced. When the brake pedal 1 is released, the front wheel side volume variable actuator 3
0 is returned to the initial position.

It is generally said that the driver's sudden braking when the danger is about to occur is due to insufficient depression of the brake pedal, and therefore the braking force exerted on the wheel brakes is also insufficient.

However, as described above, according to the embodiment of the present invention, each wheel brake 17 by the front wheel side volume variable actuator 30 responds to the sudden depression of the brake pedal 1 by the driver at the time of danger. , 18
It is possible to supply a sufficient braking force by the braking force exerted on. Needless to say, the ABS control is performed immediately when the brake lock occurs at this time.

When the front wheel side volume variable actuator 30 is pressure-increased, if the specific response pressure is exceeded on the wheel brakes 17 and 18 side, it is detected via the pressure sensor 13 that the electronic control unit 21 has exceeded the specific response pressure. , The solenoid 12 is operated to communicate with the master cylinder 3, and the wheel brake 1
The high-pressure brake fluid pressures on the 7 and 18 sides are controlled to be released to the master cylinder 3 to prevent the wheel brake area from becoming high. Further, when the rear wheel side volume variable actuator 30 becomes inoperable during pressure increase, the electronic control unit 21 detects a failure of the volume variable actuator 30, operates the solenoid 15 and operates the wheel brakes 19 and 20 and the master cylinder 3. Is communicated with each other, and the high-pressure brake fluid pressure on the wheel brakes 19 and 20 side is controlled to be discharged to the master cylinder 3 to prevent the wheel brakes 19 and 20 sides from becoming high pressure.

FIG. 4 is a flow chart showing the processing contents of the electronic control unit 21. First, in step S1, it is determined whether the brake switch 1a is on, and if it is on, it is determined in step S2 whether the differential pressure sensor 13 is on. If the differential pressure sensor 13 is on, the variable volume actuator is pressure-increased in step S3, and the process proceeds to step S4. In step S4, it is determined whether or not the wheels are locked. If not, it is determined in step S5 whether or not the brake switch 1a is off. If it is off, the variable volume actuator is returned to the initial position in step S6. It When it is determined in step S5 that the brake switch 1a is not off, it is determined in step S7 whether the vehicle is stopped or the accelerator pedal is on. If not, the process returns to step S4. When it is determined in step S7 that the vehicle is stopped or the accelerator pedal is turned on, the process proceeds to step S6. If it is determined in step S4 that the wheels are locked, step S4 is performed.
8, the variable volume actuator is drive-controlled in the ABS mode.

[0049]

As described above, according to the present invention,
(EN) It is possible to provide a braking force control device having an auxiliary function of covering insufficient pedaling force or the like during braking when a danger is about to occur.

In addition, the hydro brake booster and T
In a system having an actuator capable of increasing the pressure, such as an RC actuator, it is not necessary to newly provide a vacuum brake booster for automatic control, and a slight change in the hydraulic pressure path is insufficient for braking at the time of danger. It is possible to provide a braking force control device having an auxiliary function of covering the pedaling force and the like.

Further, in the conventional braking force control device having an auxiliary function of covering a lacking pedaling force or the like at the time of braking when a danger is about to occur, the brake pedal becomes lighter and enters when the auxiliary function is activated. According to the present invention, the pedal rigidity is improved and the feeling is improved without entering.

[Brief description of drawings]

FIG. 1 is a brake hydraulic circuit diagram according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the variable volume actuator according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of FIG.

FIG. 4 is a flowchart showing the processing contents of the electronic control unit.

FIG. 5 is a brake fluid pressure circuit diagram including a conventional braking force control device.

[Explanation of symbols]

 1 Brake Pedal 1a Brake Pedal Switch 2 Brake Booster 3 Master Cylinder 4 Reservoir Tank 5 Fluid Pressure Path 6, 7, 8, 9, 12, 15 Solenoid Valve 10, 11 Bypass 13 Differential Pressure Sensor 14 Orifice 16 Proportioning Valve 17, 18 , 19, 20 Wheel brake 21 Electronic control unit CPU 30 Variable volume actuator 31 Motor 32 Housing 32a Cylinder hole 32a 'Breaking part 33 Plunger 33a First plunger 33b Second plunger 33b' Breaking part 34 First valve 34a Valve body 34a 'Elasticity Body 34a '' Metal body 34b Valve seat 35 Second valve 35a Ball valve body 35b Valve seat 36 Pressure control chamber 37, 39 Seal cup 38 Spring 40 Locking part 41 Nut 42 First wheel gear 43 Screw Material 44 second wheel gear 45, 46 spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunari Takeuchi 2-1, Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd. (72) Inventor Akira Nishio 2-1-2, Asahi-cho, Kariya city, Aichi prefecture Address Aisin Seiki Co., Ltd.

Claims (1)

[Claims] 1. A master cylinder that generates a brake hydraulic pressure by operating a brake operating member, a wheel brake that communicates with the master cylinder via a hydraulic pressure path and operates by receiving the brake hydraulic pressure, and the brake operating member. A hydraulic pressure control actuator disposed in the hydraulic pressure path for controlling the brake hydraulic pressure of the wheel brake during operation of the wheel brake and applying the brake hydraulic pressure to the wheel brake when the brake operation member is not operating, In a braking force control device including a control means for controlling the operation of a hydraulic control actuator, a brake fluid having a predetermined value or more between the master cylinder and the wheel brake when the brake operating member is suddenly operated. In order to generate a pressure difference, the hydraulic pressure path between the hydraulic control actuator and the master cylinder is turned on. Provided is a brake fluid pressure difference detection means for detecting that a brake fluid pressure difference of the predetermined value or more has occurred between the master cylinder and the wheel brake, and inputting a predetermined signal to the control means. The control means is configured to actuate the fluid pressure control actuator in response to a predetermined signal from the brake fluid pressure difference detection means to apply a brake fluid pressure to the wheel brakes. apparatus.