Electronic parking control system with voltage pre-building function

Abstract

The invention relates to the technical field of braking systems, in particular to an electronic parking control system with a voltage pre-building function. An electronic parking control system with a voltage pre-building function is characterized in that a hydraulic braking control module, a sensor module, an electronic parking braking system control unit and an electronic parking braking system switch are in CAN signal transmission connection; the hydraulic brake control module is connected with the left front wheel hydraulic brake caliper, the right front wheel hydraulic brake caliper, the left rear wheel electronic parking brake caliper and the right rear wheel electronic parking brake caliper through hydraulic transmission. The electronic parking braking system control unit is connected with the left rear wheel electronic parking braking calipers and the right rear wheel electronic parking braking calipers through electric transmission. Compared with the prior art, by monitoring the vehicle state, the driver state and the driver intention in real time, the ECU triggers the brake hydraulic system to build pressure to act on the brake piston before parking, and meanwhile the electronic parking control system is driven, so that the needed clamping force is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of braking systems, and more specifically, to an electronic parking control system with a pre-built pressure function. Background Art

[0002] The electronic parking brake system (EPB) is a relatively common disc parking brake system that replaces the traditional mechanical lever and cable, providing more convenient and safer functions for the driver. The braking force applied to the wheels by both the electronic parking brake and the service brake is generated by pushing the piston in the hydraulic cylinder of the brake caliper. The piston acts on the friction pad, which then rubs against the brake disc to form the braking force.

[0003] The difference is that the electronic parking brake requests the parking control unit ECU to rotate the parking motor gear mechanism, which drives the transmission device to push the brake piston; while the service brake is activated when the driver presses the brake pedal, which pushes the brake fluid in the master cylinder and then the brake piston in the wheel cylinder. Therefore, regardless of whether the braking energy comes from the rotation of the motor gear or the flow of brake hydraulic pressure, the braking force can act on the wheels to ensure the safety of the vehicle.

[0004] In the current electronic parking mechanism, by energizing the EPB motor, transmitting through the reduction mechanism, and applying the output force to the piston cylinder in the electronic parking caliper, the target clamping force is achieved. And the torque is maintained by locking through the self-locking mechanism.

[0005] With the advancement of automotive electrification and intelligentization, the weight of vehicles is increasing, so the required parking force is also increasing. At the same time, the space around the vehicle rim is limited, and a larger power electronic parking actuator cannot be arranged. Vehicles that require a large parking force cannot indefinitely increase the power and volume of the EPB motor (the corresponding cost will also increase). Therefore, the design of the electronic parking actuator is becoming more and more difficult. Based on the fact that brake hydraulic pressure can also act on the brake wheel cylinder, and most current vehicles are equipped with an ECU controller for active pressure building, it is possible, without changing the design, to build a larger parking torque by jointly applying hydraulic pressure and the EPB motor to the brake piston under some conditions that require a higher parking force (such as on a steep slope). Subsequently, the electronic parking control system maintains the established combined force on the wheels through the self-locking mechanism to ensure the safe parking of the vehicle. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides an electronic parking control system with a pre-built pressure function, which can monitor the vehicle state, driver state, and driver intention in real time. The ECU triggers the brake hydraulic system to build pressure and act on the brake piston before parking, and at the same time drives the electronic parking control system to achieve the required clamping force.

[0007] To achieve the above object, an electronic parking control system with a pre - built - up pressure function is designed, which includes a hydraulic braking control module, a left front wheel hydraulic brake caliper, a right front wheel hydraulic brake caliper, a sensor module, an electronic parking brake system switch, an electronic parking brake system control unit, a left rear wheel electronic parking brake caliper, and a right rear wheel electronic parking brake caliper. It is characterized in that: there is a CAN signal transmission connection among the hydraulic braking control module, the sensor module, the electronic parking brake system control unit, and the electronic parking brake system switch; the hydraulic braking control module is respectively connected to the left front wheel hydraulic brake caliper, the right front wheel hydraulic brake caliper, the left rear wheel electronic parking brake caliper, and the right rear wheel electronic parking brake caliper through hydraulic transmission; the electronic parking brake system control unit is respectively connected to the left rear wheel electronic parking brake caliper and the right rear wheel electronic parking brake caliper through electrical transmission.

[0008] The sensor module includes a wheel speed sensor, a slope sensor, a temperature sensor, a brake pedal position sensor, a hydraulic sensor, a gear position sensor, a door state sensor, and a seat belt state sensor.

[0009] The driver transmits the parking intention through the electronic parking brake system switch.

[0010] The electronic parking brake system control unit analyzes the data of each sensor in the sensor module in real - time, judges whether the pre - built - up pressure trigger condition is met, and sends a hydraulic request and an electronic parking actuator clamping request to the hydraulic braking control module through the CAN bus signal.

[0011] The hydraulic braking control module receives the control hydraulic pressure target value from the electronic parking brake system control unit, executes hydraulic pre - built - up pressure, and feeds back the hydraulic value to the electronic parking brake system control unit; during the pressure - building process, the hydraulic braking control module only acts on the rear axle to establish braking hydraulic pressure.

[0012] The electronic parking brake caliper, with the help of hydraulic pressure, simultaneously the electronic parking actuator executes a clamping action. When the target clamping force is reached, the electronic parking actuator stops working, and the parking force is maintained through a self - locking mechanism to safely park the vehicle, and at the same time the established hydraulic request is removed.

[0013] A pre - built - up pressure method for an electronic parking control system is as follows:

[0014] S1, Parking request;

[0015] S2, The electronic parking brake system control unit receives the parking request;

[0016] S3, The electronic parking brake system control unit judges the vehicle through the CAN bus according to the real - time data of each sensor, and judges the driver's state;

[0017] In S4, the electronic parking brake system control unit calculates the required total clamping force and performs pre - pressure build - up;

[0018] In S5, the electronic parking brake system control unit sends requests to the hydraulic brake control module and the electronic parking actuator respectively;

[0019] In S6, the electronic parking brake system control unit sends the required electronic clamping force to the electronic parking actuator; at the same time, the hydraulic brake control module establishes the hydraulic parking force and determines within a certain time whether the hydraulic brake control module feeds back the information that the establishment has been completed to the electronic parking brake system control unit. If so, continue to step S7; otherwise, jump to step S11;

[0020] In S7, the left - rear wheel electronic parking brake caliper and the right - rear wheel electronic parking brake caliper start to clamp;

[0021] In S8, the parking force reaches the requirement;

[0022] In S9, the electronic parking brake system control unit cancels the hydraulic parking request and sets the parking state to parked at the same time;

[0023] In S10, the hydraulic parking is removed;

[0024] In S11, the electronic parking brake system control unit sets a fault and performs the parking action only through the clamping force established by the electronic parking actuator;

[0025] In S12, the electronic parking brake system control unit sets the parking state to unknown and notifies the driver;

[0026] In S13, end.

[0027] The total clamping force is F clamp = F mech + F hyd ; where F mech is the mechanical parking force, F hyd is the hydraulic parking force, that is, the pressure exerted by the hydraulic pressure on the brake caliper piston.

[0028] The mechanical parking force F mech > M req / 2 * μ * r eff , where M req is the parking braking torque, μ is the static friction coefficient between the friction pad and the brake disc, r eff is the effective braking radius at which the parking braking torque acts on the brake disc, mveh is the full - load weight of the vehicle, α slope is the slope at which the vehicle is parked, rdyn is the dynamic rolling radius of the wheel, and g is the acceleration due to gravity.

[0029] The described F hyd = P * S; where P is the pressure acting on the brake caliper piston and S is the force-receiving area.

[0030] Compared with the prior art, the present invention provides an electronic parking control system with a pre-built pressure function, which can monitor the vehicle state, driver state, and driver intention in real time. The ECU triggers the brake hydraulic system to build pressure acting on the brake piston before parking, and at the same time drives the electronic parking control system to achieve the required clamping force. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the module connection diagram in the electronic parking control system of the present invention.

[0032] Figure 2 is the signal transmission schematic diagram of each module in the electronic parking control system of the present invention.

[0033] Figure 3 is the mechanical analysis diagram of the parking braking torque.

[0034] Figure 4 is the distribution diagram of each force in the mechanical clamping force.

[0035] Figure 5 is the flow chart of the present invention.

[0036] Figure 6 is the schematic diagram of the parking force.

[0037] Figure 7 is the schematic diagram of the pre-built pressure simulation result.

[0038] Figure 8 is the schematic diagram of the pure mechanical parking ability test.

[0039] Figure 9 is the schematic diagram of the parking ability test after mechanical parking with superposed hydraulic pressure. DETAILED DESCRIPTION OF THE INVENTION

[0040] The following further describes the present invention with reference to the drawings.

[0041] As Figure 1 , Figure 2As shown in the figure, an electronic parking control system with a pre-built pressure function includes a hydraulic braking control module, a left front wheel hydraulic brake caliper, a right front wheel hydraulic brake caliper, a sensor module, an electronic parking brake system switch, an electronic parking brake system control unit, a left rear wheel electronic parking brake caliper, and a right rear wheel electronic parking brake caliper. The hydraulic braking control module 1, the sensor module 4, the electronic parking brake system control unit 6, and the electronic parking brake system switch 5 are connected by CAN signal transmission; the hydraulic braking control module 1 is respectively connected to the left front wheel hydraulic brake caliper 3, the right front wheel hydraulic brake caliper 2, the left rear wheel electronic parking brake caliper 8, and the right rear wheel electronic parking brake caliper 7 through hydraulic transmission; the electronic parking brake system control unit 6 is respectively connected to the left rear wheel electronic parking brake caliper 8 and the right rear wheel electronic parking brake caliper 7 through electrical transmission.

[0042] The sensor module 4 includes a wheel speed sensor, a slope sensor, a temperature sensor, a brake pedal position sensor, a hydraulic sensor, a gear position sensor, a door state sensor, and a seat belt state sensor.

[0043] The driver transmits the parking intention through the electronic parking brake system switch 5.

[0044] The electronic parking brake system control unit 6 analyzes the data of each sensor in the sensor module 4 in real time, determines whether the pre-built pressure trigger condition is met, and sends a hydraulic request and an electronic parking actuator clamping request to the hydraulic braking control module 1 through the CAN bus signal.

[0045] The hydraulic braking control module 1 receives the control hydraulic pressure target value of the electronic parking brake system control unit 6, executes hydraulic pre-built pressure, and feeds back the hydraulic value to the electronic parking brake system control unit 6; during the pressure building process, the hydraulic braking control module 1 only acts on the rear axle to establish braking hydraulic pressure.

[0046] The electronic parking brake caliper, with the help of hydraulic pressure, simultaneously the electronic parking actuator executes a clamping action. When the target clamping force is reached, the electronic parking actuator stops working and maintains the parking force through a self-locking mechanism to safely park the vehicle, and at the same time the established hydraulic request is removed.

[0047] As Figure 5 shown, a pre-built pressure method for an electronic parking control system is as follows:

[0048] S1, Parking request;

[0049] S2, The electronic parking brake system control unit 6 receives the parking request.

[0050] S3, The electronic parking brake system control unit 6 judges the vehicle through the CAN bus according to the real-time data of each sensor, and judges the state of the driver.

[0051] In S4, the electronic parking brake system control unit 6 calculates the required total clamping force and performs pre - pressure build - up;

[0052] In S5, the electronic parking brake system control unit 6 sends requests to the hydraulic brake control module 1 and the electronic parking actuator respectively;

[0053] In S6, the electronic parking brake system control unit 6 sends the required electronic clamping force to the electronic parking actuator; at the same time, the hydraulic brake control module 1 builds the hydraulic parking force and determines within a certain time whether the hydraulic brake control module 1 feeds back the information that the building is completed to the electronic parking brake system control unit 6. If so, continue with step S7; otherwise, jump to step S11;

[0054] In S7, the left - rear wheel electronic parking brake caliper 8 and the right - rear wheel electronic parking brake caliper 7 start to clamp;

[0055] In S8, the parking force reaches the requirement;

[0056] In S9, the electronic parking brake system control unit 6 cancels the hydraulic parking request and sets the parking state to parked at the same time;

[0057] In S10, the hydraulic parking is removed;

[0058] In S11, the electronic parking brake system control unit 6 sets a fault and performs the parking action only with the clamping force established by the electronic parking actuator;

[0059] In S12, the electronic parking brake system control unit 6 sets the parking state to unknown and notifies the driver;

[0060] In S13, end.

[0061] As Figure 3 , Figure 4 shown, the total clamping force is F clamp = F mech + F hyd ; where F mech is the mechanical parking force, F hyd is the hydraulic parking force, that is, the pressure exerted by the hydraulic pressure on the brake caliper piston.

[0062] The mechanical parking force F mech > M req / 2 * μ * r eff , where, M req is the parking braking torque, μ is the static friction coefficient between the friction plate and the brake disc, r eff$r$ is the effective braking radius at which the parking brake torque acts on the brake disc, $m_{veh}$ is the full-load weight of the vehicle, and $\alpha$ slope is the slope at which the vehicle is parked, and $r$ dyn is the dynamic rolling radius of the wheel, and $g$ is the acceleration due to gravity.

[0063] $F$ hyd $= P*S$; where $P$ is the pressure acting on the brake caliper piston and $S$ is the force-receiving area.

[0064] As Figure 6 shown, it is a schematic diagram of the parking force. The green curve is the mechanical parking force superimposed on the hydraulic parking force. When the target parking force is reached, the electronic parking brake system requests to cancel the hydraulic parking, and the parking force maintained by the electronic parking actuator through the self-locking mechanism. The orange curve is the pure mechanical parking ability that the electronic parking actuator can achieve, and the blue curve is the hydraulic parking force.

[0065] As Figure 7 shown, it is a schematic diagram of the pre-built pressure simulation result. The blue is the requested hydraulic value, the red is the current curve of the EPB motor actuator, and the black is the parking force that the entire system can achieve. It can be clearly seen that the mechanical parking force superimposed on the hydraulic parking force has a significant increase.

[0066] As Figure 8 shown, it is a schematic diagram of the pure mechanical parking ability test. It can be seen from the figure that the mechanical parking ability can only reach 16000 N.

[0067] As Figure 9 shown, it is a schematic diagram of the parking ability test after the mechanical parking is superimposed with the hydraulic pressure. It can be seen from the figure that its parking ability reaches 23000 N, with a significant increase.

Claims

1. An electronic parking control system with a pre - built pressure function, comprising a hydraulic braking control module, a left front wheel hydraulic brake caliper, a right front wheel hydraulic brake caliper, a sensor module, an electronic parking brake system switch, an electronic parking brake system control unit, a left rear wheel electronic parking brake caliper, and a right rear wheel electronic parking brake caliper, characterized in that: There is a CAN signal transmission connection between the hydraulic brake control module (1), the sensor module (4), the electronic parking brake system control unit (6), and the electronic parking brake system switch (5); the hydraulic brake control module (1) is hydraulically connected to the left front wheel hydraulic brake caliper (3), the right front wheel hydraulic brake caliper (2), the left rear wheel electronic parking brake caliper (8), and the right rear wheel electronic parking brake caliper (7) respectively; the electronic parking brake system control unit (6) is electrically connected to the left rear wheel electronic parking brake caliper (8) and the right rear wheel electronic parking brake caliper (7) respectively.

2. The electronic parking control system with a pre-built pressure function according to claim 1, characterized in that: The said sensor module (4) includes a wheel speed sensor, a slope sensor, a temperature sensor, a brake pedal position sensor, a hydraulic sensor, a gear state sensor, a door state sensor, and a seat belt state sensor.

3. The electronic parking control system with a pre-built pressure function according to claim 1, wherein: The driver transmits the parking intention through the electronic parking brake system switch (5).

4. The electronic parking control system with a pre-built pressure function according to claim 1, characterized in that: The said electronic parking brake system control unit (6) analyzes the data of each sensor in the sensor module (4) in real time, determines whether the pre-pressurization trigger condition is met, and sends a hydraulic request and an electronic parking actuator clamping request to the hydraulic brake control module (1) through the CAN bus signal.

5. An electronic parking control system with a pre-built pressure function according to claim 1, characterized in that: The said hydraulic brake control module (1) receives the control hydraulic pressure target value of the electronic parking brake system control unit (6), performs hydraulic pre-pressurization, and feeds back the hydraulic value to the electronic parking brake system control unit (6); During pressurization, the hydraulic brake control module (1) only acts on the rear axle to establish braking hydraulic pressure.

6. The electronic parking control system with a pre - built - in pressure function according to claim 1, characterized in that: The said electronic parking brake caliper, with the help of hydraulic pressure, simultaneously the electronic parking actuator performs a clamping action. When the target clamping force is reached, the electronic parking actuator stops working, and the parking force is maintained through a self-locking mechanism to safely park the vehicle. At the same time, the established hydraulic request is removed.

7. A pre-pressurization method for an electronic parking control system, characterized in that: The specific method is as follows: S1, Parking request; S2, The electronic parking brake system control unit (6) receives the parking request; S3, The electronic parking brake system control unit (6) judges the vehicle through the CAN bus according to the real-time data of each sensor, and judges the driver's state; S4, The electronic parking brake system control unit (6) calculates the total required clamping force and performs pre-pressurization; S5, The electronic parking brake system control unit (6) sends requests to the hydraulic brake control module (1) and the electronic parking actuator respectively; S6, The electronic parking brake system control unit (6) sends the required electronic clamping force to the electronic parking actuator; At the same time, the hydraulic brake control module (1) establishes a hydraulic parking force, and judges within a certain time whether the hydraulic brake control module (1) feeds back the information that the establishment is completed to the electronic parking brake system control unit (6). If so, continue to step S7; otherwise, jump to step S11; S7, The left rear wheel electronic parking brake caliper (8) and the right rear wheel electronic parking brake caliper (7) start to clamp; S8, The parking force reaches the requirement; S9, The electronic parking brake system control unit (6) removes the hydraulic parking request and sets the parking state to parked at the same time; S10, The hydraulic brake parking is removed; S11. The electronic parking brake system control unit (6) malfunctions and performs the parking operation only by the clamping force established by the electronic parking actuator; S12. The electronic parking brake system control unit (6) sets the parking state as unknown and notifies the driver; S13. End.

8. An electronic parking control system with a pre-built pressure function according to claim 7, characterized in that: The total clamping force is F clam = F mech + F hyd ; where F mech is the mechanical parking force, and F hyd is the hydraulic parking force, that is, the pressure exerted by the hydraulic pressure on the brake caliper piston.

9. An electronic parking control system with a pre-built pressure function according to claim 8, characterized in that: The mechanical parking force F mech >M req / 2*μ*r eff , where M req is the parking braking torque, μ is the static friction coefficient between the friction plate and the brake disc, r eff is the effective braking radius at which the parking braking torque acts on the brake disc, mveh is the full-load weight of the vehicle, α slope is the slope at which the vehicle is parked, r dyn is the dynamic rolling radius of the wheel, and g is the acceleration due to gravity.

10. A kind of electronic parking control system with pre - built - in pressure function according to claim 8, characterized in that: The described F hyd = P * S; where P is the pressure acting on the brake caliper piston and S is the force-receiving area.

Images