KR100381777B1 - Electronic hydraulic brake system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrohydraulic brake (EHB) system, comprising a potentiometer sensor 102 and a pressure sensor mounted on a master cylinder 101 generating a hydraulic pressure corresponding to a force provided to a brake pedal 100. 103 detects the displacement of the brake pedal and the hydraulic pressure in the master cylinder 101, respectively, and provides the controller 112, and the wheel pressure sensors 125, 126, 127, 128 provide the wheel brakes 115, 116, 123. Wheel speed sensors 129, 130, 131, and 132 provide the controller 112 with the rotational speed of the wheels. The controller 112 controls the drive of the wheel brakes 125, 126, 127, 128, respectively, by controlling the drive of the gears 113, 114, 121, 122 in response to these information.

Description

ELECTROHYDRAULIC BRAKE SYSTEM

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrohydraulic brake (EHB) system, and more particularly to an EHB system capable of controlling four wheels of an automobile, respectively.

The current brake system is a hydraulic system including a booster device, and ABS, TCS system, etc. have been added and spread. The development direction of the braking system is moving toward the driver's comfort and ease of driving. For example, autonomous vehicle guiding system (AVGS) functions such as ACC (Autonomous Cruise Control), CAS (Collision Avoidance System) required for Intelligent Vehicle Highway System (IVHHS), and upgrades such as Hill-Holder systems. ), PA (Parking Aid) function. This capability requires a braking device with the ability to easily integrate many systems with complex functions. However, the hydraulic hardware used in the past has a limit in achieving this function.

On the other hand, as the recently developed electronic control method has better performance in terms of price or easy integration of complex systems, a lot of research is being used to develop the braking device hardware.

As a result of this study, an EHB system as shown in FIG. 1 has been proposed. The illustrated EHB system schematically depicts US Patent Publication No. 5,558,409, which controls the hydraulic pressure provided to the wheel brake 11 using the controller 3 and the motor 8 as shown.

That is, when the driver presses the pedal 1 as shown, the displacement of the pedal 1 is sensed by the potentiometer sensor 2 and provided to the controller 3. On the other hand, the displacement of the pedal 1 is mechanically provided to the master cylinder 4, and the pressure sensor 5 applies hydraulic information provided to the master cylinder 4 to the controller 3.

The master cylinder 3 provides the hydraulic pressure corresponding to the driver's force applied through the brake pedal 1 to the solenoid valve 7 via the line 6, and the solenoid valve 7 controls the control of the controller 3. It is opened and closed accordingly.

Here, the controller 3 senses the drive of the brake pedal 1 through the potentiometer sensor 2 and the pressure sensor 5 to close the solenoid valve 7 and the motor in response to the driving force of the brake pedal 1. (8) is driven. In response to the driving of the motor 8, the brake pressure regulator 9 adjusts the pressure of the hydraulic pressure through the passage 10 and provides it to the wheel brake 11.

That is, in the conventional EHB system shown, when the brake pedal 1 is driven, the controller 3 closes the solenoid valve 7 and drives the motor 8 in response to the driving force of the pedal 1, thereby adjusting the brake pressure regulator. (9) to control the hydraulic force provided to the wheel brake (11).

Therefore, even when the user drives the pedal with a small force, there is an advantage that a strong hydraulic pressure through the passage 10 can be provided to the wheel brake 11 by the force by the motor 8.

However, in this conventional invention, there is a problem that the pressure difference control problem of the front and rear wheels occurs by controlling the same for all four wheels.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an EHB system capable of independently controlling four wheels of a vehicle.

To achieve this object, the present invention provides an electrohydraulic brake system, comprising: a master cylinder for generating hydraulic pressure corresponding to a force provided to a brake pedal; A potentiometer sensor mounted on a master cylinder and detecting a displacement of the brake pedal; A pressure sensor for detecting hydraulic pressure in the master cylinder according to the driving of the brake pedal; Motors for respectively lowering the hydraulic pressure from the master cylinder and operating the gears corresponding to the four wheels of the vehicle according to the control signal to provide the wheel brakes of the four wheels of the vehicle; Solenoid valves for selectively providing the gears with hydraulic pressure of the master cylinder provided to the gears according to the control signal; Wheel speed sensors respectively detecting rotational speeds of four wheels of the vehicle; Shock pressure sensors for measuring the hydraulic pressure provided to the wheel brakes; And a controller for controlling the driving of the motor and the solenoid valve in response to the information sensed by the potentiometer sensor, the pressure sensor, the wheel speed sensor, and the wheel pressure sensors.

1 is a schematic diagram of a conventional electrohydraulic brake system,

2 is a schematic block diagram of an electrohydraulic brake system according to the present invention;

3 is a schematic view of a dispensing valve configured in an electrohydraulic brake system according to the present invention;

4 is a flow chart of the operation of the electrohydraulic brake system according to the invention.

<Description of the symbols for the main parts of the drawings>

100: brake pedal 101: master cylinder

102: potentiometer sensor 103: pressure sensor

112: controller

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic block diagram of an EHB system according to the present invention. As shown, the master cylinder 101 is connected to the brake pedal 100, and the master cylinder 101 generates hydraulic pressure corresponding to the force provided through the brake pedal 100. On the other hand, the master cylinder 101 is equipped with a potentiometer sensor 102, the potentiometer sensor 102 detects the movement displacement of the brake pedal 100, and provides the detected movement displacement to the controller 112 do. In addition, the master cylinder 101 is equipped with a pressure sensor 103, the pressure sensor 103 provides the controller 112 with information about the hydraulic pressure of the master cylinder 100 by the driving of the brake pedal 100. .

The hydraulic pressure generated in the master cylinder 101 is provided to the solenoid valves 107 and 108 and the distribution valve 109 through the passages 104 and 105, respectively. The solenoid valves 107 and 108 are controlled by the control of the controller 112 and the hydraulic pressure from the solenoid valves 107 and 108 is controlled by the operation of the gears 113 and 114 driven by the motors 110 and 111. The hydraulic pressure is doubled and provided to the wheel brakes 115 and 116 of the front wheel FR and the front left wheel FL, respectively.

On the other hand, the distribution valve 109 distributes the hydraulic pressure from the passages 104 and 105 to the solenoid valves 117 and 118 as will be described later. The solenoid valves 117 and 118 are controlled by the control of the controller 112, and the hydraulic pressure from the solenoid valves 117 and 118 is controlled by the operation of the gears 121 and 122 driven by the motors 119 and 120. The oil pressure is doubled and provided to the wheel brakes 123 and 124 of the wheel RR on the rear right side and the wheel RL on the rear left side, respectively.

On the other hand, the wheel brakes 115, 116, 123, and 124 are configured with wheel pressure sensors 125-128, and the wheel pressure sensors 125-128 measure the applied hydraulic pressure and provide them to the controller 112. In addition, wheel speed sensors 129-132 are configured on four wheels FR, FL, RL, and RR of the vehicle, and are configured to provide the controller 112 with the rotation speed of the four wheels.

The controller 112 is connected to an interface device (not shown), and is configured to input various information (for example, vehicle speed information, steering angle information, etc.) necessary for driving the vehicle from the interface device.

The operation of the device configured as described above is as follows.

In normal normal operation, the controller 112 controls the solenoid valves 107, 108, 117, and 118 in the open state. In this state, when the brake pedal 100 is operated, the potentiometer sensor 102 and the pressure sensor 103 are controlled. Provides the controller 112 with drive initiation and movement displacement and pressure information of the brake pedal 100.

At this time, the controller 112 inputs the wheel speed of the four wheels FR, FL, RL, RR, vehicle speed information from the interface device, steering angle information, etc. from the wheel speed sensors 129-132 as described above, The pressure provided to the wheel brakes 115, 116, 123, 124 from the wheel pressure sensors 125-128 is input to drive the motors 110, 111, 119, 120 accordingly. That is, the pressure provided through the passages 104 and 105 is increased / decreased according to the positional change of the gears 113, 114, 121, and 122 according to the driving of the motors 10, 111, 119, and 120, so that the wheel brake ( 115, 116, 123, 124.

Here, a distribution valve 109 is formed in the solenoid valves 117 and 118 connected between the passages 104 and 105 and the rear wheels RL and RR of the vehicle. The distribution valve 109 is for providing a higher oil pressure to the rear wheel valve (FR, FL) than the current (FR, FL) of the vehicle. That is, since the braking force of the rear wheels FR and FL is higher than the front wheels FR and FL at the time of braking of the vehicle, such a distribution valve 109 is configured.

The distribution valve 109 can be configured as shown in FIG. 3. Here, the distribution valve 109 shown in FIG. 3 is configured in the passages 104 and 105, respectively. The distribution valve 109 is provided with a large diameter piston 201 and a large chamber 204 having a plurality of holes 202 and 203 formed on one side thereof, and a small diameter piston 205 provided with the large chamber 204. ) Is provided with a small chamber (206) in communication with. Here, the large diameter piston 201 and the small diameter piston 205 are connected by the connecting rod 207 so that the large diameter piston 201 and the small diameter piston 205 move together with each other, and the large diameter chamber ( The predetermined holes 208 and 209 are formed between the 204 and the small diameter chamber 206.

The piston 201 of the large diameter of the distribution valve 109 comprised in this way is connected with the rear wheel RR, RL side, and the piston 205 of the small diameter is connected with the front wheel side FR, FL. At this time, when the hydraulic pressure by the pedal 100 is transmitted to the piston 205 of the small diameter, the braking oil is collected in the area 211 of the chamber 206 of the small diameter, and the pressure is transmitted to the large diameter piston 201. At this time, when the pistons 201 and 205 are moved by the pressure difference provided to the large diameter piston 201 and the small diameter piston 205, air is introduced through the holes 202, 203, 208 and 209 of the large diameter and small diameter chambers 204 and 206. Both pistons 201 and 205 are subjected to the same force because they maintain atmospheric pressure. Therefore, the pressure ratio is inversely proportional to the area ratio of the two pistons 201 and 205. That is, when the area ratio of the large diameter piston 201 and the small diameter piston 205 is 10: 1, the pressure ratio is 1:10.

Therefore, the hydraulic pressure provided through the passage 104 and the hydraulic pressure provided through the distribution valve 109 generate a 1:10 pressure difference, and thus a high braking force is applied to the rear wheels RL and RR.

4 shows a flow chart of operation in the device configured as described above.

As shown, the controller 112 starts normal operation and the brake pedal 100 is driven 301 to initiate braking of the wheel brakes 115, 116, 123, 124. The controller 112 generates an initial break interrupt (302). The controller 112 performs step 303 to determine whether it is in normal operation by examining the overall operational state of the EHB system by this initial break interrupt. Here, although not shown, it can be easily understood by those of ordinary skill in the art that it is possible to indicate that the abnormal state using a separate display unit if the system is not in normal operation.

As a result of the determination in step 303, if it is in the normal operating state, the controller 112 inputs information from the potentiometer sensor 101 and the hydraulic sensor 102 (304, 305), and the wheel speed sensors 129, 130, 131. 132 to calculate the speed of the vehicle by inputting the wheel speed (306 and 307).

The controller 112 inputs actual vehicle speed information from the interface device (308), and determines whether the actual vehicle speed and the calculated vehicle speed are the same (309).

As a result of the determination in step 309, if an error between the actual vehicle speed and the calculated vehicle speed exceeds a predetermined threshold value, an ABS routine is performed (310). Otherwise, the routine proceeds to step 311 to interrupt the normal brake control interruption. Do

When a general brake control interrupt is applied, the wheel brakes 115, 116, 123, and 124 must be provided to correspond to the displacement and pressure of the brake pedal 100 detected by the potentiometer sensor 101 and the pressure sensor 102. Calculate the hydraulic pressure to be operated 312 and operate the gears 113, 114, 121, 122 by driving the motors 110, 111, 119, 120 to provide the calculated hydraulic pressure (313).

Then, it is determined whether the difference between the hydraulic pressure substantially applied to the wheel brakes 115, 116, 123, and 124 and the calculated hydraulic pressure is greater than or equal to the predetermined threshold value (314), and if it is less than or equal to the threshold value, the process proceeds to step 315. In step 315, it is determined whether or not the break interrupt process has been terminated, and if not, the process returns to step 303, but when the break interrupt process ends, all processes are finished. However, as a result of the determination of step 313, if the difference between the applied hydraulic pressure and the calculated hydraulic pressure is greater than or equal to the threshold, the flow returns to step 313 to perform the above-described process again. That is, the steps 313-315 are continuously performed until the hydraulic pressure to be provided to the wheel brakes 115, 116, 123, and 124 is provided to the wheel brakes 115, 116, 123, and 124.

Accordingly, as can be seen from the above description, in the present invention, the hydraulic pressure provided to the four wheels of the vehicle by the EHB method is provided by using separate hydraulic control means, that is, a motor and a gear for each wheel, respectively. Independent control is possible.

Claims (2)

Electrohydraulic Brake (EHB) system, A master cylinder providing hydraulic pressure corresponding to a force provided to the brake pedal; A potentiometer sensor mounted on the master cylinder and detecting a displacement of the brake pedal; A pressure sensor detecting a hydraulic pressure in the master cylinder according to the driving of the brake pedal; Motors for respectively lowering the hydraulic pressure from the master cylinder and operating the gears corresponding to the four wheels of the vehicle according to a control signal to provide the wheel brakes to the four wheels of the vehicle; Solenoid valves for selectively providing hydraulic pressure of the master cylinder provided to the gears according to a control signal to the gears; Wheel speed sensors detecting respective rotational speeds of the four wheels of the vehicle; Shock pressure sensors for measuring hydraulic pressure provided to the wheel brakes; And a controller for controlling driving of the motor and the solenoid valve in response to information sensed by the potentiometer sensor, pressure sensor, wheel speed sensor, and wheel pressure sensors. The electrohydraulic brake system according to claim 1, further comprising a distribution valve disposed between the solenoid valve and the master cylinder and configured to lower and provide hydraulic pressure on the rear wheel side than hydraulic pressure provided on the solenoid valve on the front wheel side of the vehicle.