KR102372397B1 - Braking device for vehicle - Google Patents

Abstract

The present invention relates to a vehicle braking system, wherein the first cylinder unit generates hydraulic pressure by pressing a pedal, the second cylinder unit transmits the hydraulic pressure of the first cylinder unit, and the second cylinder unit amplifies the hydraulic pressure by the second cylinder unit. 3 cylinder unit, an electric driving unit for electrically driving the second cylinder unit, a hydraulic pressure control unit disposed between the first cylinder unit and the second cylinder unit to adjust hydraulic pressure, and a hydraulic pressure connected to the hydraulic pressure control unit to store hydraulic pressure Including the storage unit, it is possible to stably secure pedal effort and emergency braking force.

Description

Brake system for vehicle {BRAKING DEVICE FOR VEHICLE}

The present invention relates to a vehicle braking system, and more particularly, to a vehicle braking system capable of smoothly braking when an error occurs in an electric booster and providing a stable pedal effort even when the pedal simulator is deleted.

In general, a vehicle brake system generates friction by pushing a brake pad to decelerate a driving vehicle or maintain a parked state.

On the other hand, regenerative braking is a technology for improving fuel efficiency by charging a battery by a motor driving a vehicle functioning as a generator during braking in an electric vehicle or a hybrid vehicle.

At this time, since the amount of regenerative braking of the driving motor does not necessarily operate in proportion to the amount of the driver pressing the brake pedal, the existing friction braking has to perform the remaining insufficient part. Also, as the amount of regenerative braking is not constant, friction braking does not increase or decrease in proportion to the amount of the driver pressing the brake pedal, so in some cases, active braking that increases or decreases regardless of this is required. In addition, this increase/decrease should be a fluctuation that the driver does not feel, and the driver should feel the same or similar pedal effort as the existing vehicle. This can be called the regenerative braking cooperative control function of friction braking.

In summary, in order to respond to such regenerative braking cooperative control with an electric booster that does not have a pedal simulator, the following function definition is required.

First, the braking pressure (braking pressure that generates friction braking) that varies within the section where regenerative braking is performed should not be transmitted to the driver.

Second, even within the section where regenerative braking is performed, the existing pedal effort must be delivered to the driver without a pedal simulator.

In order to satisfy the first condition, a certain gap is placed between the part that pressurizes the master cylinder and the part connected to the pedal that the driver steps on so that the pedal force is not mechanically transmitted to the braking force during a certain gap section. More specifically, in the transmission system in which the driver's pedal force generates the hydraulic pressure of the primary master cylinder and this is again transferred to the hydraulic pressure of the secondary master cylinder connected to the braking motor, the hydraulic pressure in the primary master cylinder for a certain period (regenerative braking period) In order to prevent this from occurring, design to intentionally increase the invalid stroke section.

In order to satisfy the second condition, the elastic force of the return spring of the primary master cylinder is increased to realize a pedal effort similar to that of a normal brake device. However, if the elastic force of the return spring is increased, there is a problem in that it is difficult to perform emergency braking only with the pressure of the primary master cylinder when a braking motor (electric booster) error occurs. Therefore, there is a need to improve it.

Background art of the present invention is disclosed in Korean Patent Publication No. 2011-0065845 (published on June 16, 2011, title of the invention: vehicle braking system).

The present invention has been devised to improve the above problems, and it is an object of the present invention to provide a vehicle braking device capable of smoothly braking when an error occurs in an electric booster and providing a stable pedal effort even when the pedal simulator is deleted. .

A brake system for a vehicle according to the present invention includes: a first cylinder unit generating hydraulic pressure by pressing a pedal; a second cylinder unit that transmits the hydraulic pressure of the first cylinder unit; a third cylinder part in which hydraulic pressure is amplified by the second cylinder part; an electric driving unit for electrically driving the second cylinder unit; a hydraulic pressure control unit disposed between the first cylinder unit and the second cylinder unit to adjust hydraulic pressure; and a hydraulic pressure storage unit connected to the hydraulic pressure control unit to store hydraulic pressure.

The hydraulic control unit includes a control body in which a control flow path is formed; a first connection part formed in the control body part and guiding the hydraulic pressure supplied from the first cylinder part to the control flow path; a second connection part formed on the control body part and guiding the hydraulic pressure between the second cylinder part and the control flow path; a storage connection part formed on the control body part and guiding the hydraulic pressure between the hydraulic pressure storage part and the control flow path; and a control valve part built in the control flow path and selectively providing hydraulic pressure to the second connection part and the storage connection part according to the hydraulic pressure supplied through the first connection part.

The control valve unit may include a valve piston unit configured to open and close the storage connection unit while moving in the control flow path by the hydraulic pressure supplied through the first connection unit; a valve spring part built into the control passage and elastically supporting the valve piston part; and a valve flow path formed inside the control body, communicating with the control flow path, and guiding hydraulic pressure by bypassing the valve piston.

When the hydraulic pressure is not supplied through the first connection part, the valve piston part opens the storage connection part so that the second cylinder part and the hydraulic pressure storage part are connected.

When hydraulic pressure is supplied through the first connection part, the valve piston part is moved to close the storage connection part, and the valve flow path part is opened to connect the first cylinder part and the second cylinder part.

The braking device for a vehicle according to the present invention can stably secure the pedal effort and the emergency braking force even without increasing the spring force of the first cylinder.

The brake system for a vehicle according to the present invention is capable of regenerative braking cooperative control while the valve piston of the hydraulic pressure control unit moves.

1 is a view schematically showing a vehicle braking system according to an embodiment of the present invention.
2 is a diagram schematically illustrating a state in which a hydraulic pressure control unit opens a storage connection unit in a vehicle braking system according to an embodiment of the present invention.
3 is a diagram schematically illustrating a state in which the hydraulic control unit closes the storage connection unit in the vehicle braking system according to an embodiment of the present invention.
4 is a graph schematically illustrating an emergency braking force by a vehicle braking system according to an embodiment of the present invention.

Hereinafter, an embodiment of a vehicle braking system according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

1 is a view schematically showing a vehicle braking system according to an embodiment of the present invention. Referring to FIG. 1 , a vehicle braking device 1 according to an embodiment of the present invention includes a first cylinder part 10 , a second cylinder part 20 , a third cylinder part 30 , and an electric driving part. (40), and includes a hydraulic control unit 50, and a hydraulic storage unit (60).

The first cylinder part 10 generates hydraulic pressure by pressing the pedal 100 . For example, the driver may step on the pedal 100 with a foot for braking, and the first cylinder unit 10 may discharge the built-in oil as the pedal 100 is pressed. The first cylinder part 10 includes a pedal pipe part in which oil is stored, a pedal pressing part that is linked with the pedal 100 to pressurize the oil stored in the pedal pipe part, and a pedal restoration part that provides restoring force to the pedal pressing part. can A spring may be used as the pedal restoration unit.

The second cylinder unit 20 transmits the hydraulic pressure of the first cylinder unit 10 . For example, the first cylinder unit 10 and the second cylinder unit 20 may be connected through the hydraulic flow passage unit 200 to move hydraulic pressure.

In the third cylinder unit 30 , the hydraulic pressure is amplified by the second cylinder unit 20 , and the electric driving unit 40 electrically drives the second cylinder unit 20 . For example, the third cylinder unit 30 includes a master pipe arranged in the longitudinal direction of the second cylinder unit 20, a master cylinder interlocking with the second cylinder unit 20 to amplify the internal hydraulic pressure of the master pipe, and a master It may include a master spring for elastically supporting the cylinder. And, the second cylinder unit 20 may move the master cylinder by the hydraulic pressure supplied from the first cylinder unit 10 . In addition, the second cylinder unit 20 may move the master cylinder by linear movement due to screw coupling when the electric driving unit 40 is driven by a motor.

The hydraulic pressure control unit 50 is disposed between the first cylinder unit 10 and the second cylinder unit 20 to adjust the hydraulic pressure. For example, the hydraulic pressure control unit 50 may be formed in the hydraulic flow passage unit 200 to adjust the hydraulic pressure movement direction.

The hydraulic pressure storage unit 60 is connected to the hydraulic pressure control unit 50 to store the hydraulic pressure. For example, the hydraulic pressure storage unit 60 may be mounted on the first cylinder unit 10 , and may store a part of the hydraulic pressure amplified in the first cylinder unit 10 .

2 is a view schematically showing a state in which the hydraulic control unit opens the storage connection in the brake system for a vehicle according to an embodiment of the present invention, and FIG. It is a diagram schematically showing a state in which the connection part is closed. 1 to 3 , the hydraulic control unit 50 according to an embodiment of the present invention includes an adjustment body 51 , a first connection unit 52 , a second connection unit 53 , and a storage connection unit. (54), and a control valve unit (55).

The adjustment body 51 has an adjustment flow path 59 formed therein. For example, the adjustment body 51 is formed to have a length in the vertical direction, the adjustment flow path 59 may be formed in the longitudinal direction of the adjustment body portion (51). The control flow passage 59 may include a first flow passage 591 formed at an upper portion and a second flow passage 592 communicating with the first flow passage 591 . The first flow path 591 has a larger internal cross-sectional area than the second flow path 592 , and thus a step 58 may be formed. Meanwhile, the first flow path 591 may be formed to have a shorter length than the second flow path 592 .

The first connecting portion 52 is formed in the adjustment body portion 51 , and guides the hydraulic pressure supplied from the first cylinder portion 10 to the adjustment flow passage 59 . For example, the first connection part 52 is formed at the upper end of the control body part 51 to communicate with the first flow path 591 of the control flow path 59 , and the first cylinder part through the hydraulic flow path part 200 . (10) can maintain a connection state.

The second connection portion 53 is formed in the adjustment body portion 51 , and guides the hydraulic pressure between the second cylinder portion 20 and the adjustment flow passage 59 . For example, the second connection part 53 is formed under the control body part 51 , communicates with the second flow path 592 of the control flow path 59 , and the second cylinder through the hydraulic flow path part 200 . It is possible to maintain a connection state with the unit 20 .

The storage connection part 54 is formed in the adjustment body part 51 , and guides the hydraulic pressure between the hydraulic pressure storage part 60 and the adjustment flow path 59 . As an example, the storage connection unit 54 is formed on the upper portion of the control body portion 51 to communicate with the first flow passage 591 of the control flow passage 59 , and the hydraulic storage unit 60 through the storage passage portion 300 . can stay connected with

The control valve unit 55 is built into the control flow path 59 , and selectively provides hydraulic pressure to the second connection unit 53 and the storage connection unit 54 according to the hydraulic pressure supplied through the first connection unit 52 .

The control valve unit 55 according to an embodiment of the present invention includes a valve piston unit 551 , a valve spring unit 552 , and a valve flow path unit 553 .

The valve piston part 551 opens and closes the storage connection part 54 while moving in the control flow path 59 by the hydraulic pressure supplied through the first connection part 52 . For example, the valve piston unit 551 may include an elastic material, have a considerable thickness, and may open and close the storage connection unit 54 while moving along the first flow path 591 . The valve piston part 551 may be in close contact with the first flow path 591 to maintain airtightness.

The valve spring part 552 is built in the adjustment flow passage 59 and elastically supports the valve piston part 551 . As an example, the valve spring part 552 may have a coil spring shape, and may provide restoring force to the valve piston part 551 whose movement is restricted by being caught by the step 58 .

The valve flow path part 553 is formed inside the control body part 51 and communicates with the control flow path 59 . The valve passage part 553 bypasses the valve piston part 551 and guides the hydraulic pressure. For example, the valve flow path part 553 is disposed to face the storage connection part 54, and the oil introduced through the inlet part 5531 passes the bypass flow path part 5532 formed in the adjustment body part 51, It may be discharged through the outlet (5533). In this case, the inlet 5531 may communicate with the first flow path 591 , and the outlet 5533 may communicate with the second flow path 592 . In a state in which the valve piston part 551 is not moved, the valve piston part 551 may close the inlet part 5531 . And, when the valve piston part 551 is moved and caught on the step 58 , the inlet part 5531 may be opened.

On the other hand, when hydraulic pressure is not supplied through the first connection part 52 , the valve piston part 551 opens the storage connection part 54 and closes the valve flow path part 553 . For this reason, the second cylinder unit 20 and the hydraulic storage unit 60 are connected.

And, when hydraulic pressure is supplied through the first connection part 52 , the valve piston part 551 is moved to close the storage connection part 54 . At this time, the valve flow path part 553 is opened so that the first cylinder part 10 and the second cylinder part 20 are connected. Accordingly, the hydraulic pressure generated in the first cylinder unit 10 may reach the second cylinder unit 20 to drive the second cylinder unit 20 .

4 is a graph schematically illustrating an emergency braking force by a vehicle braking system according to an embodiment of the present invention. Referring to FIG. 4 , the conventional method indicates emergency braking force when the spring force on the first cylinder unit 10 is increased to secure pedal effort, and the present invention provides emergency braking force in a state in which the vehicle braking device 1 is applied. indicates.

Through this graph, it is possible to secure the pedal effort even if the spring force of the first cylinder unit 10 is not strengthened, and to minimize the decrease in braking pressure in case of an error in the electric driving unit 40 . And, when the valve piston part 551 is caught on the step 58 and movement is restricted, the pressure is not increased to the valve spring part 552 and the hydraulic pressure is transmitted through the valve flow passage part 553, so a loss due to the spring force can be reduced to improve emergency braking power.

An operation of the vehicle braking system according to an embodiment of the present invention having the above configuration will be described as follows.

If the driver does not step on the pedal 100 (see FIG. 2 ), the valve piston part 551 closes the inlet part 5531 by the valve spring part 552 and opens the storage connection part 54 . For this reason, the second cylinder unit 20 and the hydraulic storage unit 60 maintain a connected state.

When the driver steps on the pedal 100 in the above state (refer to FIG. 3), the valve piston part 551 is moved to the step 58 by the hydraulic pressure generated in the first cylinder part 10, and the storage connection part 54 close the Due to this, the connection between the second cylinder part 20 and the hydraulic storage part 60 is released. And the valve flow path part 553 is opened, and the first cylinder part 10 and the second cylinder part 20 maintain a connected state.

In this case, the pedal effort felt by the driver may include a spring force and sliding resistance of the first cylinder unit 10 , a spring force of the valve spring unit 552 , and sliding resistance of the valve piston unit 551 .

On the other hand, up to the section in which the valve piston part 551 is moved is a section in which regenerative braking cooperative control is possible. In this section, the electric driving unit 40 directly drives the second cylinder unit 20 , and a change in the position of the third cylinder unit 30 does not affect the first cylinder unit 10 . However, after this section, the hydraulic pressure of the first cylinder part 10 affects the driving of the second cylinder part 20 . At this time, since the driver's pedal force is involved in forming the braking pressure, it is possible to secure the pedal effort even if the spring force of the valve spring part 552 is limited.

The brake device 1 for a vehicle according to an embodiment of the present invention can stably secure the pedal effort and the emergency braking force even without increasing the spring force of the first cylinder unit 10 .

In the vehicle braking device 1 according to an embodiment of the present invention, regenerative braking cooperative control is possible during a section in which the valve piston 551 of the hydraulic pressure adjusting unit 50 is moved.

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and it is understood that various modifications and equivalent other embodiments are possible by those of ordinary skill in the art. will understand Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

10: first cylinder part 20: second cylinder part
30: third cylinder part 40: electric driving part
50: hydraulic control unit 51: control body unit
52: first connection part 53: second connection part
54: storage connection part 55: control valve part
59: control flow path 60: hydraulic storage unit
551: valve piston part 552: valve spring part
553: valve passage part

Claims (5)

a first cylinder unit generating hydraulic pressure by pressing the pedal;
a second cylinder unit that transmits the hydraulic pressure of the first cylinder unit;
a third cylinder part in which hydraulic pressure is amplified by the second cylinder part;
an electric driving unit for electrically driving the second cylinder unit;
a hydraulic flow passage connecting the first cylinder part and the second cylinder part;
a hydraulic pressure control unit formed in the hydraulic flow passage unit; and
Includes; a hydraulic storage unit connected to the hydraulic pressure control unit to store the hydraulic pressure;
The hydraulic control unit adjusts the hydraulic pressure movement direction to secure the pedal effort and the emergency braking force according to the driver's pedal force.
According to claim 1, wherein the hydraulic control unit
a control body in which a control passage is formed;
a first connection part formed in the control body part and guiding the hydraulic pressure supplied from the first cylinder part to the control flow path;
a second connection part formed on the control body part and guiding the hydraulic pressure between the second cylinder part and the control flow path;
a storage connection part formed on the control body part and guiding the hydraulic pressure between the hydraulic pressure storage part and the control flow path; and
and a control valve part built in the control flow path and selectively providing hydraulic pressure to the second connection part and the storage connection part according to the hydraulic pressure supplied through the first connection part.
The method of claim 2, wherein the control valve unit
a valve piston part opening and closing the storage connection part while moving in the control flow path by the hydraulic pressure supplied through the first connection part;
a valve spring part built into the control passage and elastically supporting the valve piston part; and
and a valve flow path formed inside the control body, communicating with the control flow path, and guiding hydraulic pressure by bypassing the valve piston.
4. The method of claim 3,
If hydraulic pressure is not supplied through the first connection part,
The valve piston part opens the storage connection part so that the second cylinder part and the hydraulic storage part are connected to each other.
4. The method of claim 3,
When hydraulic pressure is supplied through the first connection part,
The valve piston part is moved to close the storage connection part, and the valve flow path part is opened, so that the first cylinder part and the second cylinder part are connected.

Images