Method and device for reducing working noise of electronic parking brake (EPB)

Abstract

The invention discloses a method for reducing working noise of an electronic parking brake (EPB), which specifically comprises the following steps of: when the EPB works, controlling an EPB motor by adopting a PWM (Pulse Width Modulation) mode, and reducing the working noise of the EPB by reducing the duty ratio of the EPB motor. According to the method, the duty ratio of the EPB motor is freely adjusted based on the gradient of the position where the vehicle is located, and when the gradient is small, the noise of the EPB motor is reduced by reducing the duty ratio and the target current of the EPB motor; besides, after the target clamping force is constructed through hydraulic braking, the EPB motor is driven to maintain the target clamping force with the small target current and duty ratio, the target current I2 and the duty ratio T2 needed by the EPB motor and needed by the current slope are greatly reduced, and then noise of the EPB motor is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of braking technology. More specifically, the present invention relates to a method and device for reducing the working noise of an electronic parking brake system (EPB). Background Art

[0002] With the continuous progress of automotive technology, more and more vehicles have gradually changed from traditional mechanical control to electronic control. The electronic parking brake system (Electrical Park Brake, EPB) uses electric energy to achieve the functions of the traditional parking brake system.

[0003] When the vehicle is stationary, the electronic parking brake system (EPB) applies a certain pressure to the rear wheels to ensure that the vehicle does not roll when stationary, avoiding potential safety hazards caused by rolling. The electronic parking brake system (EPB) can be automatically activated and clamped when the vehicle is in the P gear, and can automatically withdraw and release the pressure when starting. Most vehicles on the market are equipped with an electronic parking brake system (EPB).

[0004] Since the existing electronic parking brake system (EPB) mainly uses a motor for braking, when the electronic parking brake system (EPB) is working, the motor runs at full speed under the working voltage, and a relatively large motor noise will be generated during this process, giving users a bad experience. Summary of the Invention

[0005] The present invention provides a method for reducing the working noise of an electronic parking brake system (EPB), aiming to improve the above problems.

[0006] The present invention is implemented as follows. A method for reducing the working noise of an electronic parking brake system (EPB) is as follows specifically:

[0007] When the electronic parking brake system (EPB) is working, the EPB motor is controlled in a PWM manner, and the working noise of the EPB is reduced by reducing the duty cycle of the EPB motor.

[0008] Furthermore, the parking brake method based on the EPB motor is as follows specifically:

[0009] (1) When the electronic parking brake system (EPB) is working, determine the target clamping force P based on the slope of the current parking position;

[0010] (2) Determine the target current I required to construct the target clamping force P 1 , and determine the duty cycle T of the EPB motor corresponding to the target current I 1 ; 1 ;

[0011] (3) Through the duty cycle T 1Drive the EPB motor until the target current I required for the EPB motor to reach the target clamping force P is achieved. 1 , control the EPB motor to stop, and the self-locking mechanism locks.

[0012] Furthermore, the method for determining the target clamping force P is as follows:

[0013] Test the minimum clamping force required for the current vehicle model to achieve parking at different gradients, form a gradient-clamping force mapping table, and determine the clamping force corresponding to the current gradient through the gradient-clamping force mapping table, which is the target clamping force P;

[0014] The greater the gradient of the vehicle parking position, the greater the required target clamping force P.

[0015] Furthermore, the target current I required for the EPB motor 1 is determined as follows:

[0016] Based on bench tests, determine the EPB motor current I required for the current vehicle model to build different target clamping forces P 1 , and form a clamping force P - target current I 1 mapping table;

[0017] Based on the target clamping force P, read the corresponding target current I required for the EPB motor from the clamping force P - target current I 1 table. 1 .

[0018] Furthermore, the duty cycle T of the EPB motor 1 is determined as follows:

[0019] Based on bench tests, determine the duty cycle T of the EPB motor corresponding to different target currents I 1 , and form a target current I 1 - duty cycle T 1 mapping table; 1 Based on the target current I required for the target clamping force P

[0020] read the corresponding duty cycle T of the EPB motor from the target current I 1 - duty cycle T 1 mapping table. 1 1 .

[0021] Furthermore, the parking brake method based on hydraulic braking and the EPB motor is as follows:

[0022] (1) When the electronic parking brake system EPB is working, determine the target clamping force P based on the gradient of the current parking position;

[0023] (2) According to the target current I required to maintain the target clamping force P2 Target current I 2 Less than the target current I 1 ;

[0024] (3) The EPB control module requests the hydraulic braking module to establish a clamping force P at the wheel end 1 , and the clamping force P 1 is slightly greater than the target clamping force P;

[0025] (4) Drive the EPB motor according to the set duty cycle T 2 until the EPB motor reaches the target current I required to maintain the target clamping force P 2 , the motor stops working, the self-locking mechanism locks, the hydraulic braking is released, and the duty cycle T 2 is less than the duty cycle T 1 .

[0026] Furthermore, the determination method of the target current I 2 is specifically as follows:

[0027] Determine the current required for the EPB motor to drive the self-locking mechanism to the piston position corresponding to the target clamping force P through a bench test, and construct a target clamping force P - target current I 2 mapping table;

[0028] Based on the target clamping force P, read the target current I required by the EPB motor from the target clamping force P - target current I 2 mapping table 2 .

[0029] The present invention is implemented as follows. A device for reducing the working noise of an electronic parking brake system EPB, the device includes:

[0030] An EPB control module, which is communicatively connected to the EPB motor;

[0031] The output shaft of the EPB motor is connected to the piston that pushes the brake pads through a self-locking mechanism;

[0032] Detect the slope of the current position and send the slope value to the EPB control module, and the EPB control module controls the EPB motor based on the method for reducing the working noise of the above-mentioned electronic parking brake system EPB.

[0033] Furthermore, the device further includes:

[0034] A hydraulic braking module, which drives the piston through hydraulic pressure;

[0035] The hydraulic braking module is communicatively connected to the EPB control module; the slope of the current location is detected and the slope value is sent to the EPB control module. The EPB control module sends the determined target clamping force P to the hydraulic braking module. After the hydraulic braking module constructs a clamping force slightly higher than the target clamping force P, the EPB control module controls the EPB motor based on the method for reducing the working noise of the electronic parking brake system EPB according to claim 6 or 7.

[0036] Based on the slope of the vehicle's location, the present invention adjusts the duty cycle of the EPB motor. When the slope is small, the duty cycle and target current of the EPB motor are reduced to achieve a reduction in the noise of the EPB motor. In addition, after the target clamping force is constructed by hydraulic braking, the EPB motor is driven with a smaller target current and duty cycle to maintain the target clamping force, greatly reducing the target current I required by the EPB motor at the current slope 2 and duty cycle T 2 , thereby reducing the noise of the EPB motor. Description of the Drawings

[0037] Figure 1 is a flowchart of the method for reducing the working noise of the electronic parking brake system EPB provided in Embodiment 1 of the present invention;

[0038] Figure 2 is a flowchart of the method for reducing the working noise of the electronic parking brake system EPB provided in Embodiment 2 of the present invention;

[0039] Figure 3 is a schematic structural diagram of the device for reducing the working noise of the electronic parking brake system EPB provided in the embodiments of the present invention. Detailed Embodiments

[0040] The following further details the specific embodiments of the present invention by describing the embodiments with reference to the drawings, so as to help those skilled in the art have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of the present invention.

[0041] The method for reducing the working noise of the electronic parking brake system EPB provided by the present invention is as follows: When the electronic parking brake system EPB is working, the EPB motor is controlled in a PWM manner, and the working noise of the EPB is reduced by reducing the duty cycle of the EPB motor. Different current segments correspond to different duty cycles, and the larger the current, the larger the duty cycle.

[0042] (1) Constructing a target brake based on the EPB motor Figure 1 is a flowchart of the method for reducing the working noise of the electronic parking brake system EPB provided in Embodiment 1 of the present invention. The method is as follows:

[0043] To meet the requirements of different target clamping forces, the duty cycle T of the EPB motor is adjusted in real time according to the target current required for the target clamping force P; when the required target clamping force P is small (on flat ground or small slopes), the EPB motor is controlled by a small duty cycle T to reach the target current I required for the target clamping force P 1 ; when the target clamping force P is large (on large slopes), the EPB motor is controlled by a large duty cycle T to reach the target current I required for the target clamping force P 1 , after the EPB motor reaches the target current I required for the target clamping force P 1 , the EPB motor is controlled to stop, the self-locking mechanism locks, and the position of the brake pad is locked by the self-locking mechanism, and the clamping force between it and the brake disc is maintained at the target clamping force P. Therefore, the EPB clamping control method based on the EPB motor is as follows:

[0044] (1) When the electronic parking brake system EPB is working, determine the target clamping force P based on the slope of the current parking position;

[0045] In the embodiment of the present invention, the clamping force corresponding to the current slope is determined through a slope-clamping force mapping table, which is the target clamping force P. The greater the slope of the vehicle parking position, the greater the required target clamping force P, and the smaller the slope of the vehicle parking position, the smaller the required target clamping force P. The slope-clamping force mapping table is determined through bench tests, and the determination method is as follows:

[0046] Test the minimum clamping force required to achieve parking for the current model vehicle at different slopes to form a slope-clamping force mapping table, and integrate the slope-clamping force mapping table into the electronic parking brake system EPB. When the electronic parking brake system EPB is working, read the target clamping force P from the slope-clamping force mapping table based on the slope of the current vehicle location.

[0047] (2) Determine the target current I based on the target clamping force P 1 , and determine the duty cycle T of the EPB motor 1 ;

[0048] In the embodiment of the present invention, a clamping force P - target current I 1 mapping table is constructed, and the clamping force P - target current I 1 mapping table is integrated into the electronic parking brake system EPB. Based on the target clamping force P, read the corresponding target current I from the clamping force P - target current I 1 table 1 ; among them, the acquisition method of the clamping force P - target current I 1 is as follows:

[0049] Based on bench tests, determine the EPB motor current I required to construct different target clamping forces P for the current model vehicle 1, form the clamping force P - target current I 1 , where the constructed target clamping force P refers to the clamping force that the brake pads are pushed to between the brake pads and the brake disc by the EPB motor as the target clamping force P.

[0050] In the embodiment of the present invention, based on the target current I 1 determine the duty cycle T of the EPB motor 1 , construct the target current I 1 - duty cycle T 1 mapping table, and map the target current I 1 - duty cycle T 1 mapping table is integrated into the electronic parking brake system EPB. Based on the target current I required for the target clamping force P 1 read the corresponding duty cycle T from the target current I 1 - duty cycle T 1 mapping table 1 , the target current I 1 - duty cycle T 1 The construction method of the mapping table is specifically as follows:

[0051] Based on the bench test, determine the duty cycle T of the EPB motor required to construct different target currents I 1 , and form the target current I 1 - duty cycle T 1 mapping table. 1

[0052] (3) Drive the EPB motor through the duty cycle T 1 until the EPB motor reaches the target current I required for the target clamping force P 1 , control the EPB motor to stop, and the self-locking mechanism locks.

[0053] When the current of the EPB motor reaches the target current I 1 , control the EPB motor to stop. When the EPB motor stops, the self-locking mechanism locks. At this time, the position of the brake pads is also locked, and the clamping force between the brake pads and the brake disc is maintained at the target clamping force P.

[0054] The present invention adjusts the duty cycle of the EPB motor based on the slope of the vehicle's location. When the slope is small, the noise of the EPB motor is reduced by reducing the duty cycle and target current of the EPB motor.

[0055] (2) First, construct the target braking force based on hydraulics, and then maintain the target braking force through the EPB motor. Figure 2 This is the flowchart of the method for reducing the working noise of the electronic parking brake system EPB provided in the second embodiment of the present invention. The method is specifically as follows:

[0056] ​First, provide a clamping force slightly higher than the target clamping force P through hydraulics, and then use a small duty cycle T 2 to control the EPB motor to drive the self-locking mechanism until the current of the EPB motor reaches the target current I 1 . At this time, the self-locking mechanism is located at the piston position corresponding to the target clamping force. Control the EPB motor to stop, and the self-locking mechanism locks at the piston position corresponding to the target clamping force. At this time, release the hydraulic brake, and ensure the target clamping force P through the self-locking mechanism. The EPB clamping control method based on the duty cycle is as follows

[0057] (1) When the electronic parking brake system EPB is working, determine the target clamping force P based on the slope of the current parking position;

[0058] (2) Determine the target current I according to the target clamping force P 2 , the target current I 2 is less than the target current I 1 , where the target current I 2 is used to maintain the constructed target clamping force P; therefore the target current I 2 is less than the target current I required to construct the target clamping force P 1 , the target current I 2 is obtained by looking up a table. First, construct a target clamping force P - target current I 2 mapping table, and its construction method is as follows:

[0059] Determine the current required for the EPB motor to drive the self-locking mechanism to the piston position corresponding to the target clamping force P through bench tests, and construct a mapping table of the target clamping force P and the target current I 2 ; Integrate the constructed target clamping force P - target current I 2 mapping table into the electronic parking brake system EPB. When the target clamping force P is determined, the target current I can be determined by looking up the table 2 .

[0060] (3) The EPB control module requests the hydraulic brake module to establish a clamping force P at the wheel end 1 , where the clamping force P 1 is slightly greater than the target clamping force P;

[0061] (4) Drive the EPB motor according to the set duty cycle T 2 until the EPB motor reaches the target current I required to maintain the target clamping force P 2 , the motor stops working, the self-locking mechanism locks, release the hydraulic brake, and the duty cycle T 2 is less than the duty cycle T 1 .

[0062] After the present invention constructs the target clamping force through hydraulic braking first, it then drives the EPB motor with a relatively small target current and duty cycle to maintain the target clamping force, greatly reducing the target current I required by the EPB motor for the current slope 2 and duty cycle T 2 , thereby reducing the noise of the EPB motor.

[0063] Figure 3 FIG. is a schematic structural diagram of a device for reducing the working noise of an electronic parking brake system EPB provided by an embodiment of the present invention. For the sake of clarity, only the parts related to the embodiment of the present invention are shown. The device includes:

[0064] An EPB control module, which is communicatively connected to the EPB motor;

[0065] The output shaft of the EPB motor is connected to the piston that pushes the brake pad through a self-locking mechanism;

[0066] Detect the slope of the current position and send the slope value to the EPB control module. The EPB control module controls the EPB motor based on the method for reducing the working noise of the above-mentioned electronic parking brake system EPB

[0067] In the embodiment of the present invention, the self-locking mechanism is a screw type. When the EPB motor rotates forward, it drives the screw to advance in a spiral manner, and then drives the piston and the brake pad to approach the brake disc. When the EPB motor stops rotating, the self-locking mechanism is in a locked state.

[0068] In the embodiment of the present invention, the device further includes:

[0069] A hydraulic braking module, which drives the piston through hydraulic pressure;

[0070] The hydraulic braking module is communicatively connected to the EPB control module;

[0071] Detect the slope of the current position and send the slope value to the EPB control module. The EPB control module sends the determined target clamping force P to the hydraulic braking module. After the hydraulic braking module constructs a clamping force slightly higher than the target clamping force P, the EPB control module controls the EPB motor based on the method for reducing the working noise of the above-mentioned electronic parking brake system EPB.

[0072] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for reducing the working noise of an electronic parking brake system (EPB), characterized in that, the method is as follows: When the electronic parking brake system (EPB) is working, the EPB motor is controlled in a PWM manner, and the working noise of the EPB is reduced by decreasing the duty cycle of the EPB motor.

2. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 1, characterized in that, The parking brake method based on the EPB motor is as follows: (1) When the electronic parking brake system (EPB) is working, determine the target clamping force P based on the slope of the current parking position; (2) Determine the target current I required to build the target clamping force P 1 , and determine the target current I 1 corresponding to the duty cycle T of the EPB motor 1 ; (3) Through the duty cycle T 1 Drive the EPB motor until the target current I required for the EPB motor to reach the target clamping force P 1 , control the EPB motor to stop and the self-locking mechanism locks.

3. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 2, characterized in that, The method for determining the target clamping force P is as follows: Test the minimum clamping force required for the current model vehicle to achieve parking at different slopes, form a slope-clamping force mapping table, and determine the clamping force corresponding to the current slope through the slope-clamping force mapping table, which is the target clamping force P; The greater the slope of the vehicle parking position, the greater the required target clamping force P.

4. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 2, characterized in that, The target current I required for the EPB motor 1 The determination method is as follows: Determine the EPB motor current I required to construct different target clamping forces P for the current model vehicle based on bench tests 1 , forming a clamping force P - target current I 1 mapping table; Based on the target clamping force P, from the clamping force P - target current I 1 Read the corresponding target current I required for the EPB motor from the table 1 .

5. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 2, characterized in that, Duty cycle T of the EPB motor 1 The determination method is as follows: Determine different target currents I based on bench tests 1 The corresponding EPB motor duty cycle T 1 , forming the target current I 1 - duty cycle T 1 mapping table; Target current I required based on target clamping force P 1 From the target current I 1 - Duty cycle T 1 Read the corresponding EPB motor duty cycle T from the mapping table 1 .

6. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 1, characterized in that, The parking brake method based on hydraulic braking and the EPB motor is as follows: (1) When the electronic parking brake system (EPB) is working, determine the target clamping force P based on the slope of the current parking position; (2) Target current I required to maintain the target clamping force P 2 Target current I 2 Less than the target current I 1 ; (3) The EPB control module requests the hydraulic braking module to establish a clamping force P at the wheel end 1 , the clamping force P 1 is slightly greater than the target clamping force P; (4) According to the set duty cycle T 2 Drive the EPB motor until the EPB motor reaches the target current I required to maintain the target clamping force P 2 , the motor stops working, the self-locking mechanism locks, the hydraulic brake is released, and the duty cycle T 2 is less than the duty cycle T 1 .

7. The method for reducing the working noise of the electronic parking brake system (EPB) according to claim 6, characterized in that, Target current I 2 The determination method is as follows: Determine the current required for the EPB motor-driven self-locking mechanism to reach the piston position corresponding to the target clamping force P through bench tests, and construct a target clamping force P - target current I 2 mapping table; Based on the target clamping force P, from the target clamping force P to the target current I 2 Read the target current I required for the EPB motor from the mapping table 2 .

8. A device for reducing the working noise of an electronic parking brake system (EPB), characterized in that, the device includes: An EPB control module, which is communicatively connected to the EPB motor; The output shaft of the EPB motor is connected to the piston that pushes the brake pads through a self-locking mechanism; Detect the slope of the current location and send the slope value to the EPB control module. The EPB control module controls the EPB motor based on the method for reducing the working noise of the electronic parking brake system (EPB) according to any one of claims 1 to 5.

9. The device for reducing the working noise of the electronic parking brake system (EPB) according to claim 8, characterized in that, the device further includes: A hydraulic braking module, which drives the piston through hydraulic pressure; The hydraulic braking module is communicatively connected to the EPB control module; detect the slope of the current location and send the slope value to the EPB control module. The EPB control module sends the determined target clamping force P to the hydraulic braking module. After the hydraulic braking module constructs a clamping force slightly higher than the target clamping force P, the EPB control module controls the EPB motor based on the method for reducing the working noise of the electronic parking brake system (EPB) according to claim 6 or 7.

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