KR20090119486A - Pad gab adjusting method for electric mechanical brake system - Google Patents

Abstract

PURPOSE: A pad interval adjusting method of an electric braking apparatus is provided to maintain the optimal pad interval by forming a control logic for pad interval precision control in an ECU. CONSTITUTION: A pad interval adjusting method of an electric braking apparatus comprises the following steps. An ECU(1) senses the pedal control to determine whether a vehicle is moving or is parked. If the pedal control is not sensed, an actuator assembly(2) determines whether the brake is operated for the parking through a reducer(5). The ECU decides a vehicle-stopped state through car speed information and determines whether a set braking power(Fcls) is identical or bigger to or than the real braking power(Fcla) of a piston(8). The piston pressurizes a pad(30). The ECU calculates the pad wear amount. The pad wear amount makes a change of the initial position of the piston. The ECU readjusts the set braking power for the parking brake to drive the actuator assembly.

Description

Pad gab adjusting method for Electric Mechanical Brake System

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric brake apparatus, and more particularly, to a method of adjusting a pad spacing of an electric brake apparatus.

In general, a brake system (Brake System) is a braking device that is used to maintain a parking state while at the same time decelerating or stopping a driving car.

This brake system usually uses a friction type brake that converts kinetic energy into thermal energy using friction force and releases it into the atmosphere, which brakes the disk rotating on both sides of the wheel with hydraulic pressure. Will perform the braking function.

However, the hydraulic brake, which is a method of pushing the pad strongly toward the disc by using hydraulic pressure, is operated through a booster that boosts pedal operation force to generate hydraulic pressure, and a hydraulic cylinder leading to the wheel cylinder, as well as to control them. Comprehensive configuration is inevitably made of various devices that assist and assist, and the reliability of the braking performance due to the complexity of the configuration and the use of hydraulic pressure, there is a certain limitation to the enhanced stability and the like.

Accordingly, the EMB (Electro mechanical Brake), which is an electric brake capable of bringing the simplicity of the configuration that the hydraulic brake does not have and can enhance the reliability of the braking performance, is applied.

When the EMB receives the electronic pedal information during braking, the ECU drives the motor to generate the axial movement force, and the piston is axially moved through the reducer coupled to the motor to pressurize the disk with the pad to implement braking.

However, the wear of the pad is inevitably generated when the EMB is braked due to the contact between the pad and the disk. For this purpose, a sensor for detecting the pad's wear state is added and the pad replacement cycle is determined or separately. It is possible to use the method of adjusting the initial gap exceeded by pad wear, which is difficult to control precisely the degree of pad wear, especially since it requires a separate additional device. Cost and assembly process, etc. are added to the inconvenience.

Accordingly, the present invention has been invented in view of the above. As the control logic for precisely controlling the pad spacing is added to the ECU that controls the operation of the electric brake, which is an electric brake (EMB), Its purpose is to avoid the use of additional devices that add cost and assembly process using fine control as well as control logic.

In addition, when the ECU controlling the operation of the electric brake EMB (Electro mechanical Brake) of the present invention is parked at the start state, the ECU recognizes the amount of wear of the pad and determines whether or not the pad is replaced. The purpose is to ensure that the optimum pad spacing is automatically maintained at all times as the pad is returned in consideration of the pad initial position determined before braking.

According to the present invention for achieving the above object, after the pad gap adjustment method of the electric brake device is subjected to a braking determination step of determining whether the ECU detects the pedal operation and whether the braking during the driving or parking braking when stationary,

When the ECU does not detect the pedal operation, after determining whether the vehicle is braked through the reducer of the actuator assembly, the vehicle stop state is again determined based on the vehicle speed information, and then the actuator assembly is driven with the parking braking force set at the time of parking braking. After determining whether the set braking force (a, Fcls) satisfies a value equal to or greater than the actual braking force (b, Fcla) of the piston pressurizing the pad, the change in the initial position of the piston (c, Xp_is) due to the wear of the pad is determined. After calculating the amount of pad wear (g, Xp_w) to be obtained, reverse the motor of the actuator assembly to move to the maximum position set on the pad, and then adjust the set braking force for parking braking to drive the actuator assembly, Follow the parking brake pad spacing adjustment step, along with making fine adjustments to the set spacing based on wear and tear,

When the ECU detects the pedal operation and determines the braking state while driving, the target braking force is calculated according to the vehicle driving speed to drive the actuator assemblage to move the pad to the wheel disk with the piston to implement braking. After determining whether the braking force (a, Fcls) is equal to or greater than the actual braking force (b, Fcla) of the piston pressurizing the pad, set the pad (or piston) at the travel distance (d, Xmcw) through the forward rotation motor. If the piston initial position (c, Xp_is), the difference value minus the distance (Xc) is changed due to the wear of the pad, it is characterized in that the step of adjusting the running brake pad gap that changes the output torque of the actuator assembly.

To this end, the step of adjusting the parking brake pad spacing is performed by the ECU after determining whether the set braking force (a, Fcls) satisfies a value equal to or greater than the actual braking force (b, Fcla) of the piston pressurizing the pad. Calculate the piston initial position (c, Xp_is) which is the difference value by subtracting the pad (or piston) set distance (Xc) from the movement distance (d, Xmcw) through

The piston initial position (c, Xp_is) is calculated and the motor is rotated in reverse to determine whether the piston or the pad has been moved to the maximum setting position by using a limit sensor, and then the moving distance (e) that has been retracted through the reverse rotation of the motor. , Xmccw) to calculate the pad wear (g, Xp_w) by subtracting the initial setpoint (h, Xps) of the pad.

The rotation speed of the motor is calculated to adjust the initial position of the piston (c, Xp_is) in consideration of the calculated pad wear amount (g, Xp_w), and then the motor is driven to readjust the set braking force for parking braking.

According to the present invention, the control logic for precise pad gap control is made in the ECU which controls the operation of the electric brake, EMB (Electro mechanical Brake), without the use of an additional device such as a pad wear sensor or a pad gap adjuster. The optimum pad spacing can be automatically maintained during braking or parking while driving, improving vehicle stability and driving comfort by securing a certain braking response and using only ECU control logic without using additional devices. There is no effect of adding cost and assembly process.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the exemplary embodiments of the present invention may be embodied in various different forms, one of ordinary skill in the art to which the present invention pertains may be described herein. It is not limited to the Example to make.

1 is a schematic configuration diagram of an electric brake apparatus according to the present invention, the EMB (Electro Mechanical Brake) of the electric brake system of the present invention inputs various vehicle sensor signals together with an operation button for sending a parking brake signal. The restraining force is pushed by the pad 30 toward the wheel disk through the rotational force of the receiving ECU 1, the actuator assembly 2 driven by the ECU 1 to generate the parking braking force, and the actuator assembly 2; The application is made up of a pressurized assembly 6.

In addition, the ECU 1 is further provided with control logic for informing the timing of replacement of the pad 30, while adjusting the braking force according to the wear of the pad 30, in addition to the control logic for normal parking braking. .

Here, the notification of the pad replacement timing is typically implemented by installing a lamp in the driver's seat area and lighting it in the ECU 1.

The actuator assembly 2 is mounted on the housing 9 to drive a motor 3 driven through the ECU 1 and a speed reducer for converting the motor 3 into a large output torque while decelerating the rotation speed of the motor 3. 5) consists of.

Here, the reducer 5 is composed of a variety of gear arrangements and gear types commonly applied to the EMB, the electric brake system, the final output torque is made according to the design specifications.

In addition, the press assembly 6 is mounted on the housing 9, the screw shaft 7 is rotated through the reducer 5 for generating an output torque, and the screw shaft is screwed to the screw shaft 7 It consists of the piston 8 which pushes or retracts the pad 30 according to the rotation direction of (7).

Here, the screw shaft 7 and the piston 8 are coupled in the axial direction of the screw shaft 7, and are arranged to move linearly as the screw shaft 7 is rotated.

In addition to the electric brake system EMB, the number of revolutions of the motor 3 of the actuator assembly 2, the pressing force of the pad 30 restraining the wheel disk and the wear state of the pad 30 are controlled by the ECU 1. A sensor assembly for feeding back is further provided.

The sensor assembly may include a rotation angle sensor 4 provided in the motor 3 and a pad 30 for restraining the wheel disk to detect the rotation speed of the motor 3 for the rotation of the set value of the motor 3. The load sensor 10 and the limit sensor 20 for detecting the wear of the pad 30 through the increase of the moving distance for pressing the pad 30 are configured.

Here, the load sensor 10 may be installed in a plurality of parts, for example, the motor 3, or the reducer 5 or the pad 30 is appropriately installed.

Electro-mechanical brake (EMB), the electric brake system of the present invention, parks the power of the motor 3 controlled through the ECU 1 through the movement of the piston 8 for pressing the pad 30 toward the wheel disk. In addition to implementing braking, when the pad 30 is out of the set interval of the pad due to wear or various causes, the pad 30 is readjusted at the set interval, and the driver is informed when the pad 30 is worn out. As the ECU 1 has an informing pad control logic, the set interval is always maintained irrespective of the wear of the pad 30 without the use of an expensive additional device that causes an increase in cost, and also during braking during driving. It is characterized by improving vehicle stability and driving comfort by securing a certain braking response when parking.

To this end, the ECU 1 controlling the EMB (Electro Mechanical Brake), which is an electric brake system, accurately determines the operating state of the EMB. When the braking is performed as shown in FIG. 1, the pad 30 is wheeled. Motor rotation speed measurement through the rotation angle sensor (4) installed in the motor (3) generating a driving force to pressurize the wheel disk of the, and of the pad 30 is pressed through the piston (9) through the load sensor 10 In addition to measuring the load size, information about the movement distance measurement through the limit sensor 20 which can know the degree of pad wear due to the change in the amount of movement that is moved to press the pad 30 within the set pad interval is provided in the ECU (1). ), Through which the ECU 1 implements the control logic.

That is, as shown in FIG. 2, the EMB control logic of the ECU 1 determines whether braking or parking braking is performed while driving according to the driver's pedal operation. Detects the state of the car to determine whether or not parking.

At this time, the state of the reducer 5 is determined through the load sensor 10, but can be determined using a separate sensor.

Subsequently, when the vehicle is not parked, the vehicle maintains its current state, but when the vehicle is parked, the ECU 1 again determines whether the vehicle is in the stopped state based on the vehicle speed information, and then sets the ECU 1 for the parking braking force set at the time of parking braking. ) Drives the motor 3 to push the pad 30 towards the wheel disk via the screw shaft 7 and the piston 8 via the reducer 5.

In this braking, the ECU 1 performs a fine adjustment for the setting interval of the pad 30, which is the piston 1 in which the ECU 1 presses the pad 30 by the setting braking force a, Fcls. After determining whether it satisfies the value equal to or greater than the actual braking force (b, Fcla), the piston is the difference value obtained by subtracting the pad (or piston) setting distance (Xc) from the movement distance (d, Xmcw) through the forward motor. The initial position (c, Xp_is) is calculated.

Subsequently, the ECU 1 that calculates the piston initial positions c and Xp_is rotates the motor 3 in reverse to determine whether the piston 8 or the pad 30 has been moved to the maximum setting position. ), And calculates the pad wear amount (g, Xp_w) by calculating the difference between the movement distance (e, Xmccw) retracted through the reverse rotation of the motor (3) minus the initial setting value (h, Xps) of the pad. Done.

At this time, when the calculated pad wear amount (g, Xp_w) exceeds the adjustment range, the ECU 1 turns on the lamp to confirm to the driver that it is time to replace the pad.

The ECU 1 considering the pad wear amount g and Xp_w calculated as described above calculates the rotation speed value of the motor 3 so that the piston initial position c and Xp_is is adjusted, and then readjusts the set braking force for parking braking. The motor 3 is driven.

That is, the ECU 1 reduces the rotation of the motor 3 by increasing the rotation speed of the motor 3 so that the piston 8 further advances by the calculated pad wear amount g, Xp_w. As the piston 8 screwed to the screw shaft 7 rotated through the shaft further pushes the pad 30 towards the wheel disk, the pad wear amount g, Xp_w can be readjusted to the initial pad setting interval that has been removed. Will be.

At this time, the rotation speed adjustment of the motor 3 is implemented by the ECU 1 using the rotation angle sensor (4).

Subsequently, the ECU 1 maintains the parking state by driving the motor 3 to generate a set braking force.

On the other hand, when the pedal is in operation and braking while driving, the ECU 1 calculates a target braking force according to the vehicle traveling speed, and then the screw shaft coupled to the reducer 5 for switching the output torque of the motor 3. The piston (8) is moved through (7) to press the pad 30 to the wheel disk to implement braking.

If the set braking force (a, Fcls) is equal to or greater than the actual braking force (b, Fcla) of the piston (8) pressurizing the pad (30) during braking, the ECU (1) operates the forward rotation motor. The piston initial position (c, Xp_is), which is a difference value obtained by subtracting the pad (or piston) setting distance (Xc) from the moving distance (d, Xmcw), is automatically calculated.

Subsequently, the ECU 1 having calculated the piston initial position c, Xp_is considers the piston initial position c, Xp_is changed due to the wear of the pad 30, and then changes the rotational speed of the motor 3 so as to change the pad. Braking is performed by the output torque according to the braking force considering the wear of the (30).

1 is a schematic configuration diagram of an electric brake apparatus according to the present invention

2 is a flowchart illustrating a pad spacing adjustment method of the electric brake apparatus according to the present invention.

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

1: ECU 2: Actuator assembly

3: motor 4: rotation angle sensor

5: reducer 6: pressurized assembly

7: screw shaft 8: piston

9 housing 10 load sensor

20: limit sensor 30: pad

Claims (3)

A braking determination step in which the ECU 1 detects pedal operation to determine whether the vehicle is braking while driving or parking braking when stationary; When the ECU 1 does not detect the pedal operation, it is determined whether the parking brake is performed through the reducer 5 of the actuator assembly 2, and then the vehicle stopping state is determined based on the vehicle speed information. While driving the actuator assembly 2, it is determined whether or not the set braking force a, Fcls satisfies a value equal to or greater than the actual braking force b, Fcla of the piston 8 that presses the pad 30. After calculating the pad wear amount (g, Xp_w) resulting in the change of the piston initial position (c, Xp_is) due to the wear of the pad 30, the motor of the actuator assembly 2 to move to the maximum position set in the pad Reverse rotation of (3), and then adjust the set braking force for parking braking to drive the actuator assembly (2), together with the fine adjustment for the set interval according to the wear of the pad (30) Spacing adjustment step; When the ECU 1 detects the pedal operation and determines the braking state while driving, the target braking force according to the vehicle traveling speed is calculated to drive the actuator assembly 2 to drive the pad 30 with the piston 8 to the wheel disk. The brake is moved to the side to realize braking, and after determining whether the set braking force (a, Fcls) satisfies a value equal to or greater than the actual braking force (b, Fcla) of the piston (8) pressurizing the pad (30), When the piston initial position (c, Xp_is), which is a difference value of the distance traveled by the motor (d, Xmcw) minus the pad (or piston) set distance (Xc), is changed due to the wear of the pad 30, the actuator assembly ( Adjusting the braking pad spacing for varying the output torque of 2); Pad spacing method of the electric brake device, characterized in that implemented as. The method according to claim 1, wherein when the pad wear amount (g, Xp_w) calculated in the parking brake pad spacing adjustment step exceeds the adjustment range, the ECU 1 turns on a lamp to confirm the driver that it is time to replace the pad. Pad spacing adjustment method of the electric brake apparatus made into. The method according to claim 1, wherein the parking brake pad spacing step is a value in which the ECU 1 sets the braking force (a, Fcls) equal to or greater than the actual braking force (b, Fcla) of the piston (8) to press the pad (30). After determining whether the satisfactory value is satisfied, the piston initial position (c, Xp_is), which is a difference value obtained by subtracting the pad (or piston) setting distance (Xc) from the movement distance (d, Xmcw) through the forward rotation motor, After calculating the piston initial position (c, Xp_is) by rotating the motor 3 in reverse, it is determined by the limit sensor 20 whether the piston 8 or the pad 30 is moved to the maximum setting position, The pad wear amount (g, Xp_w) is calculated by calculating the difference between the movement distance (e, Xmccw) retracted through the reverse rotation of the motor 3 minus the initial setting value (h, Xps) of the pad. The rotation speed value of the motor 3 is calculated to adjust the initial position of the piston (c, Xp_is) in consideration of the calculated pad wear amount (g, Xp_w), and then the motor adjusts the set braking force for parking braking to drive the motor 3. Pad gap adjustment method of the electric brake device, characterized in that implemented to.

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