JP2016124409A - Electric braking system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric breaking system capable of improving safety of a vehicle even in braking during a high-speed travel.SOLUTION: A disk brake 31 provided to the right and left of a vehicle comprises an electric actuator 43, and is controlled by a parking brake controller 19. The parking brake controller 19 performs anti-lock control over the right and left disk brakes 31 independently when placing the disk brakes 31 in operation in response to a braking request signal while the vehicle is in a slow-speed traveling state. The parking brake controller 19 performs the anti-lock control over the right and left disk brakes 31 together when placing the disk brakes 31 in operation in response to a braking request signal while the vehicle is in a high-speed traveling state.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electric brake system that applies a braking force to a vehicle.

  As an electric brake system provided in a vehicle such as an automobile, one that operates a brake device based on driving of an electric motor is known (Patent Document 1).

JP-A-11-321599

  Patent Document 1 describes that anti-lock control (anti-lock brake control) is possible with an electric brake device. At this time, if the anti-lock control is performed independently on the left and right wheels by the electric brake device, if the braking force is released on one wheel, only the braking force on the other wheel is obtained. Occur. If this yaw moment is generated during high-speed travel, the vehicle may become unstable.

  An object of the present invention is to provide an electric brake system that can ensure the stability of a vehicle even when braking is performed during high-speed traveling.

  In order to solve the above-described problems, an electric brake system according to the present invention propels a piston that presses a friction member against a rotating member that rotates together with a wheel, and causes the friction member to be rotated by an electric mechanism in response to a braking request signal. A control device for controlling the electric mechanism of each brake device, wherein at least a pair of brake devices that can press and hold the pressing force of the friction member are provided on the left and right sides of the vehicle. When the vehicle is operated in response to the braking request signal when the vehicle is running at a low speed, the left and right brake devices are independently anti-lock controlled so that the vehicle is at a higher speed than the low speed running state. When operating the brake device in response to the braking request signal in a running state, the left and right brake devices are anti-lock controlled together. It is characterized by a door.

  According to the electric brake system of the present invention, the stability of the vehicle can be ensured even when braking is performed during high-speed traveling.

The conceptual diagram of the vehicle carrying the electric brake system by embodiment. The longitudinal cross-sectional view which expands and shows the disc brake of the rear-wheel side in FIG. The block diagram which shows the parking brake control apparatus in FIG. The flowchart which shows the process of emergency stop control.

  Hereinafter, an electric brake system according to an embodiment will be described with reference to the accompanying drawings, taking as an example a case where the electric brake system is mounted on a four-wheeled vehicle. Each step of the flowchart shown in FIG. 4 uses the notation “S”, and for example, step 1 is indicated as “S1”.

  In FIG. 1, for example, left and right front wheels 2 (FL, FR) and left and right rear wheels 3 (RL, RR) are formed on a lower side (road surface side) of a vehicle body 1 constituting a vehicle body. A total of four wheels are provided. The front wheel 2 and the rear wheel 3 are provided with a disc rotor 4 as a braked member (rotating member) that rotates together with the respective wheels (the front wheels 2 and the rear wheels 3). The disc rotor 4 for the front wheel 2 is given a braking force by a hydraulic disc brake 5, and the disc rotor 4 for the rear wheel 3 is given a braking force by a hydraulic disc brake 31 with an electric parking brake function. The Thereby, a braking force is applied to each wheel (each front wheel 2, each rear wheel 3) independently of each other.

  A brake pedal 6 is provided on the front board side of the vehicle body 1. The brake pedal 6 is depressed by the driver when the vehicle is braked, and braking force is applied and released as a service brake (service brake) based on this operation. The brake pedal 6 is provided with a brake operation detection sensor (brake sensor) 6A such as a brake lamp switch, a pedal switch, and a pedal stroke sensor. The brake operation detection sensor 6 </ b> A detects whether or not the brake pedal 6 is depressed, or the operation amount thereof, and outputs a detection signal to the hydraulic pressure supply controller 13. The detection signal of the brake operation detection sensor 6A is transmitted, for example, via a vehicle data bus 16 or a signal line (not shown) connecting the hydraulic pressure supply device controller 13 and the parking brake control device 19 ( Is output to the parking brake control device 19).

  The depression operation of the brake pedal 6 is transmitted to the master cylinder 8 that functions as a hydraulic pressure source via the booster 7. The booster 7 is configured as a negative pressure booster or an electric booster provided between the brake pedal 6 and the master cylinder 8, and increases the pedal force when the brake pedal 6 is depressed and transmits it to the master cylinder 8. At this time, the master cylinder 8 generates hydraulic pressure with the brake fluid supplied from the master reservoir 9. The master reservoir 9 is composed of a hydraulic fluid tank that stores brake fluid. The mechanism for generating the hydraulic pressure by the brake pedal 6 is not limited to the above configuration, and a mechanism for generating the hydraulic pressure in response to the operation of the brake pedal 6, for example, a brake-by-wire mechanism or the like may be used. .

  The hydraulic pressure generated in the master cylinder 8 is sent to a hydraulic pressure supply device 11 (hereinafter referred to as ESC 11) via, for example, a pair of cylinder side hydraulic pipes 10A and 10B. The ESC 11 is disposed between each of the disc brakes 5, 31 and the master cylinder 8, and distributes the hydraulic pressure from the master cylinder 8 to each of the disc brakes 5, 31 via the brake side piping portions 12A, 12B, 12C, 12D. To do. Thereby, a braking force is applied to each of the wheels (each front wheel 2 and each rear wheel 3) independently of each other. In this case, even if the ESC 11 does not follow the operation amount of the brake pedal 6, the ESC 11 can supply the hydraulic pressure to the disc brakes 5, 31, that is, increase the hydraulic pressure of the disc brakes 5, 31.

  For this purpose, the ESC 11 has a dedicated control device configured by, for example, a microcomputer, that is, a hydraulic pressure supply device controller 13 (hereinafter referred to as a control unit 13). The control unit 13 opens and closes each control valve (not shown) of the ESC 11 and performs drive control to rotate and stop an electric motor (not shown) for the hydraulic pump, thereby controlling the brake side. Control is performed to increase, decrease or maintain the brake fluid pressure supplied from the piping parts 12A to 12D to the respective disc brakes 5, 31. As a result, various brake controls such as boost control, braking force distribution control, brake assist control, antilock control (ABS control), traction control, vehicle stabilization control (including skid prevention), slope start assist control, Automatic operation control or the like is executed.

  The control unit 13 is supplied with power from the battery 14 through the power supply line 15. As shown in FIG. 1, the control unit 13 is connected to a vehicle data bus 16. A known ABS unit can be used instead of the ESC 11. Furthermore, it is also possible to directly connect the master cylinder 8 and the brake side piping parts 12A to 12D without providing the ESC 11 (that is, omitted).

  The vehicle data bus 16 includes a CAN (Controller Area Network) as a serial communication unit mounted on the vehicle body 1, and is connected to a large number of electronic devices mounted on the vehicle, the control unit 13, the parking brake control device 19, and the like. Multiplex communication within the vehicle is performed. In this case, vehicle information sent to the vehicle data bus 16 includes, for example, a brake operation detection sensor 6A, a pressure sensor 17 for detecting a master cylinder hydraulic pressure (brake hydraulic pressure), an ignition switch, a seat belt sensor, a door lock sensor, Door open sensor, seating sensor, vehicle speed sensor, steering angle sensor, accelerator sensor (accelerator operation sensor), throttle sensor, engine rotation sensor, stereo camera, millimeter wave radar, gradient sensor, shift sensor, acceleration sensor, wheel speed sensor, vehicle The information (vehicle information) by the detection signal from the pitch sensor etc. which detect the motion of the pitch direction of this is mentioned.

  In the vehicle body 1, a parking brake switch (PKBSW) 18 is provided in the vicinity of a driver's seat (not shown). The parking brake switch 18 is operated by the driver. The parking brake switch 18 transmits a signal (operation request signal) corresponding to a parking brake operation request (apply request, release request) from the driver to the parking brake control device 19. That is, the parking brake switch 18 releases and applies the apply request signal as a brake request signal for applying the brake pad 33 (see FIG. 2) based on the drive (rotation) of the electric motor 43B. Is output to the parking brake control device 19 serving as a control unit (controller).

  When the driver operates the parking brake switch 18 to the braking side (parking brake ON side), that is, when there is an apply request (holding request, driving request) for applying braking force to the vehicle, the parking brake switch An apply request signal is output from 18. As an operation on the brake side (braking ON operation) by the driver, for example, an operation of raising the parking brake switch 18 is applicable. When this braking ON operation is performed, the parking brake control device 19 supplies power for rotating the electric motor 43B to the braking side to the electric motor 43B of the disc brake 31. Thereby, the disc brake 31 for the rear wheel 3 is in a state where a braking force as a parking brake or an auxiliary brake is applied, that is, in an applied state.

  On the other hand, when the driver operates the parking brake switch 18 to the braking release side (parking brake OFF side), that is, when there is a release request (release request) for releasing the braking force of the vehicle, the parking brake A release request signal is output from the switch 18. As an operation on the brake release side (braking OFF operation) by the driver, for example, a pressing operation of the parking brake switch 18 corresponds. When this braking OFF operation is performed, the parking brake control device 19 supplies power for rotating the electric motor 43B in the direction opposite to the braking side to the electric motor 43B of the disc brake 31. As a result, the disc brake 31 for the rear wheel 3 is in a state in which the application of the braking force as the parking brake or the auxiliary brake is released, that is, in the released state.

  Here, the parking brake operates while the vehicle is stopped. For example, when the vehicle stops for a predetermined time (for example, when the vehicle is decelerated during traveling, it is determined that the vehicle speed sensor detects that the speed detected by the vehicle speed sensor is less than 4 km / h continues for a predetermined time), the engine Based on the automatic apply request by the parking brake apply determination logic in the parking brake control device 19, such as when it is stopped, when the shift lever is operated to P, when the door is opened, when the seat belt is released, etc. , It can be configured to automatically give (auto-apply). In addition, the parking brake is used when, for example, the vehicle travels (for example, it is determined that the vehicle travels when the detection speed of the vehicle speed sensor is 5 km / h or more continues for a predetermined time as the vehicle speed increases from when the vehicle is stopped). Is operated, when the clutch pedal is operated, when the shift lever is operated other than P, N, etc., based on the automatic release request by the parking brake release determination logic in the parking brake control device 19 It can be configured to automatically release (auto release).

  On the other hand, the auxiliary brake operates during traveling of the vehicle. When there is an apply request from the parking brake switch 18 during traveling of the vehicle, more specifically, this auxiliary brake has a request for a dynamic parking brake such as urgently using the parking brake as an auxiliary brake during traveling. Will be activated if Here, the auxiliary brake is automatically applied and released by the parking brake control device 19 according to the state of the wheels (each rear wheel 3), that is, whether or not the wheels are locked (slip). (ABS control) is performed. The specific operation of such a dynamic parking brake and the specific configuration and control processing of the parking brake control device 19 will be described in detail later.

  Next, the configuration of the disc brake 31 with an electric parking brake function provided on the left rear wheel 3 side and the right rear wheel 3 side will be described with reference to FIG. In FIG. 2, only one of the disc brake 31 of the left rear wheel 3 and the disc brake 31 of the right rear wheel 3 is shown.

  A pair of disc brakes 31 provided on the left and right sides of the vehicle are configured as hydraulic disc brakes provided with an electric parking brake function. The disc brake 31 constitutes a brake system (brake device) together with the parking brake control device 19. The disc brake 31 includes a mounting member 32 attached to a non-rotating part on the rear wheel 3 side of the vehicle, an inner side and outer side brake pad 33 as a braking member (friction member), and a brake provided with an electric actuator 43. It includes a caliper 34 as a mechanism.

  In this case, the disc brake 31 extends the wheel (rear wheel 3) by propelling the brake pad 33 with the piston 39 and pressing the disc rotor 4 with the brake pad 33 by the hydraulic pressure based on the operation of the brake pedal 6 or the like. The braking force is applied to the vehicle. In addition to this, the disc brake 31 is rotated (rotated) by the electric motor 43B in response to an operation request based on a signal from the parking brake switch 18, an application / release determination logic of the parking brake, and an operation request based on ABS control. By pushing the disc rotor 4 with the brake pad 33 (through the linear motion conversion mechanism 40) and pushing the disc rotor 4 with the brake pad 33, a braking force is applied to the wheel (rear wheel 3) and thus to the vehicle.

  The mounting member 32 includes a pair of arm portions (not shown) that extend in the axial direction of the disk rotor 4 (that is, the disk axial direction) so as to straddle the outer periphery of the disk rotor 4, and are separated from each other in the disk circumferential direction. A thick-walled support portion 32A that is fixed to a non-rotating portion of the vehicle at a position on the inner side of the disk rotor 4 and is connected to the base end side of the disk rotor 4; And a reinforcing beam 32B for connecting the distal end sides of the arm portions to each other.

  The brake pads 33 on the inner side and the outer side are disposed so as to be able to contact both surfaces of the disk rotor 4 and are supported by the respective arm portions of the mounting member 32 so as to be movable in the disk axial direction. The brake pads 33 on the inner side and the outer side are pressed against both sides of the disc rotor 4 by calipers 34 (caliper body 35, piston 39). Thereby, the brake pad 33 gives a braking force to the vehicle by pressing the disc rotor 4 that rotates together with the wheels (rear wheels 3).

  A caliper 34 serving as a wheel cylinder is disposed on the mounting member 32 so as to straddle the outer peripheral side of the disk rotor 4. The caliper 34 includes a caliper main body 35 supported so as to be movable along the axial direction of the disc rotor 4 with respect to each arm portion of the mounting member 32, a piston 39 provided in the caliper main body 35, and a rotation / linear motion conversion mechanism. 40, an electric actuator 43, and the like. The caliper 34 propels the brake pad 33 using a piston 39 that is operated by a hydraulic pressure generated based on the operation of the brake pedal 6.

  The caliper main body 35 includes a cylinder part 36, a bridge part 37, and a claw part 38. The cylinder portion 36 is formed in a bottomed cylindrical shape in which one side in the axial direction is closed by a partition wall portion 36 </ b> A and the other side facing the disk rotor 4 is opened. The bridge portion 37 is formed to extend from the cylinder portion 36 in the disc axial direction so as to straddle the outer peripheral side of the disc rotor 4. The claw portion 38 is disposed so as to extend radially inward from the bridge portion 37 on the side opposite to the cylinder portion 36.

  The cylinder portion 36 of the caliper main body 35 is supplied with hydraulic pressure accompanying the depression operation of the brake pedal 6 or the like via the brake side piping portion 12C or 12D shown in FIG. The cylinder portion 36 is integrally formed with the partition wall portion 36A. The partition wall portion 36 </ b> A is located between the cylinder portion 36 and the electric actuator 43. The partition wall portion 36A has a through hole in the axial direction, and an output shaft 43C of the electric actuator 43 is rotatably inserted on the inner peripheral side of the partition wall portion 36A.

  In the cylinder portion 36 of the caliper main body 35, a piston 39 as a pressing member (moving member) and a rotation / linear motion conversion mechanism 40 are provided. In the embodiment, the rotation / linear motion conversion mechanism 40 is accommodated in the piston 39. However, the rotation / linear motion conversion mechanism 40 may be configured to propel the piston 39 and may not necessarily be accommodated in the piston 39.

  The piston 39 moves the brake pad 33 in a direction toward the disk rotor 4 or in a direction away from the disk rotor 4. The piston 39 is open on one side in the axial direction, faces the brake pad 33 on the inner side, and is closed on the other side in the axial direction by a lid portion 39A. The piston 39 is inserted into the cylinder part 36. In addition to the movement of the piston 39 when electric current is supplied to the electric actuator 43 (electric motor 43B), the hydraulic pressure is supplied into the cylinder portion 36 based on the depression of the brake pedal 6 or the like. Moving. In this case, the movement of the piston 39 by the electric actuator 43 (electric motor 43B) is performed by being pressed by the linear motion member. Further, the rotation / linear motion conversion mechanism 40 is accommodated in a piston 39, and the piston 39 is configured to be propelled in the axial direction of the cylinder portion 36 by the rotation / linear motion conversion mechanism 40.

  The rotation / linear motion conversion mechanism 40 functions as a pressing member holding mechanism. Specifically, the rotation / linear motion conversion mechanism 40 propels the piston 39 of the caliper 34 by an external force different from the force generated by the addition of the hydraulic pressure into the cylinder portion 36, that is, the force generated by the electric actuator 43. The propelled piston 39 and the brake pad 33 are held. Thereby, a parking brake will be in an applied state or a holding state. On the other hand, the rotation / linear motion conversion mechanism 40 retracts the piston 39 in the direction opposite to the propulsion direction by the electric actuator 43, and sets the parking brake to the released state (released state). Since the left and right disc brakes 31 are provided for the left and right rear wheels 3, respectively, the rotation / linear motion conversion mechanism 40 and the electric actuator 43 are also provided on the left and right sides of the vehicle, respectively.

  The rotation / linear motion conversion mechanism 40 includes a screw member 41 having a rod-like body in which a male screw such as a trapezoidal screw is formed, and a linear motion member 42 in which a female screw hole formed by the trapezoidal screw is formed on the inner peripheral side (spindle). Configured as a nut mechanism). The linear motion member 42 is a driven member (propulsion member) that moves toward the piston 39 by the electric actuator 43 or in a direction away from the piston 39. That is, the screw member 41 screwed to the inner peripheral side of the linear motion member 42 constitutes a screw mechanism that converts the rotational motion by the electric actuator 43 into the linear motion of the linear motion member 42. In this case, the female screw of the linear motion member 42 and the male screw of the screw member 41 form a pressing member holding mechanism by using a highly irreversible screw, in the embodiment, a trapezoidal screw.

  The pressing member holding mechanism (rotation / linear motion converting mechanism 40) holds the linear motion member 42 (that is, the piston 39) at an arbitrary position by a frictional force (holding force) even when power supply to the electric motor 43B is stopped. It has become. The pressing member holding mechanism only needs to be able to hold the piston 39 at a position propelled by the electric actuator 43. For example, the pressing member holding mechanism may be a normal triangular cross-section screw or a worm gear having a large irreversibility other than a trapezoidal screw.

  The screw member 41 that is screwed to the inner peripheral side of the linear motion member 42 is provided with a flange portion 41A that is a large-diameter flange on one side in the axial direction. The other side of the screw member 41 in the axial direction extends toward the lid portion 39 </ b> A of the piston 39. The screw member 41 is integrally connected to the output shaft 43C of the electric actuator 43 at the flange portion 41A. Further, on the outer peripheral side of the linear motion member 42, the linear motion member 42 is prevented from rotating with respect to the piston 39 (relative rotation is restricted), and the linear motion member 42 is allowed to relatively move in the axial direction. A protrusion 42A is provided. Thereby, the linear motion member 42 moves linearly when the electric motor 43B is driven, contacts the piston 39, and moves the piston 39.

  The electric actuator 43 constitutes an electric mechanism and is fixed to the caliper body 35 of the caliper 34. The electric actuator 43 operates (applies / releases) the disc brake 31 based on the operation request signal of the parking brake switch 18, the above-described parking brake apply / release determination logic, and ABS control. The electric actuator 43 includes a casing 43A attached to the outside of the partition wall portion 36A, an electric motor 43B that is positioned in the casing 43A and moves the piston 39 when supplied with electric power (current). And a speed reducer (not shown) that amplifies the torque of the electric motor 43B, and an output shaft 43C that outputs the rotational torque amplified by the speed reducer. The electric motor 43B can be configured as a DC brush motor, for example. The output shaft 43C extends through the partition wall portion 36A of the cylinder portion 36 in the axial direction, and at the end of the flange portion 41A of the screw member 41 in the cylinder portion 36 so as to rotate integrally with the screw member 41. It is connected.

  For example, the coupling mechanism between the output shaft 43C and the screw member 41 can be configured to be movable in the axial direction but to be prevented from rotating in the rotational direction. In this case, a known technique such as spline fitting or fitting with a polygonal column (non-circular fitting) is used. As the speed reducer, for example, a planetary gear speed reducer or a worm gear speed reducer may be used. Further, when a known speed reducer having no reverse operation (irreversible) such as a worm gear speed reducer is used, the reversible known mechanism such as a ball screw or a ball ramp mechanism is used as the rotation / linear motion converting mechanism 40. Can be used. In this case, for example, the pressing member holding mechanism can be configured by a reversible rotation / linear motion conversion mechanism and an irreversible speed reducer.

  When the parking brake switch 18 shown in FIGS. 1 to 3 is operated to the braking side (braking ON operation), power is supplied to the electric motor 43B via the parking brake control device 19, and the output shaft 43C of the electric actuator 43 is rotated. The For this reason, the screw member 41 of the rotation / linear motion conversion mechanism 40 is rotated integrally with the output shaft 43C in one direction, and propels (drives) the piston 39 toward the disk rotor 4 via the linear motion member 42. Thus, the disc brake 31 is in a state where the disc rotor 4 is sandwiched between the inner side and outer side brake pads 33 and a braking force is applied as an electric parking brake, that is, an applied state or a held state.

  On the other hand, when the parking brake switch 18 is operated to the braking release side (braking OFF operation), the screw member 41 of the rotation / linear motion conversion mechanism 40 is rotationally driven in the other direction (reverse direction) by the electric actuator 43. As a result, the linear motion member 42 (and the piston 39 if no hydraulic pressure is applied) is driven in a direction away from the disc rotor 4, and the disc brake 31 is in a state in which the application of the braking force as a parking brake is released, that is, , The release state (release state).

  In this case, in the rotation / linear motion converting mechanism 40, when the screw member 41 is rotated relative to the linear motion member 42, the rotation of the linear motion member 42 within the piston 39 is restricted. Moves relatively in the axial direction according to the rotation angle of the screw member 41. Thereby, the rotation / linear motion converting mechanism 40 converts the rotational motion into a linear motion, and the piston 39 is driven by the linear motion member 42. At the same time, the rotation / linear motion conversion mechanism 40 holds the linear motion member 42 at an arbitrary position by a frictional force with the screw member 41, so that the piston 39 and the brake pad 33 are propelled by the electric actuator 43. Hold on.

  A thrust bearing 44 is provided on the partition wall portion 36 </ b> A of the cylinder portion 36 between the partition wall portion 36 </ b> A and the flange portion 41 </ b> A of the screw member 41. The thrust bearing 44 receives a thrust load from the screw member 41 together with the partition wall portion 36A, and smoothly rotates the screw member 41 with respect to the partition wall portion 36A. In addition, a seal member 45 is provided between the partition wall portion 36A of the cylinder portion 36 and the output shaft 43C of the electric actuator 43. The seal member 45 leaks brake fluid in the cylinder portion 36 to the electric actuator 43 side. It seals between the two so as to prevent it.

  A piston seal 46 as an elastic seal that seals between the cylinder portion 36 and the piston 39 and a dust boot 47 that prevents foreign matter from entering the cylinder portion 36 are provided on the opening end side of the cylinder portion 36. It has been. The dust boot 47 is a flexible bellows-like seal member, and is attached between the opening end of the cylinder portion 36 and the outer periphery of the piston 39 on the lid portion 39A side.

  The disc brake 5 for the front wheel 2 is configured in substantially the same manner as the disc brake 31 for the rear wheel 3 except for the parking brake mechanism. That is, the disc brake 5 for the front wheel 2 does not include the rotation / linear motion conversion mechanism 40 that operates as a parking brake, the electric actuator 43, and the like provided in the disc brake 31 for the rear wheel 3. However, instead of the disc brake 5, a disc brake 31 with an electric parking brake function may be provided for the front wheel 2.

  In the embodiment, the hydraulic disc brake 31 having the electric actuator 43 has been described as an example. However, for example, an electric disc brake having an electric caliper, an electric drum brake that applies a braking force by pressing a shoe against the drum by an electric actuator, a disc brake having an electric drum type parking brake, and a cable being pulled by an electric actuator The brake member (pad, shoe) is pressed (promoted) against the member to be braked (rotor, drum) based on the driving of the electric actuator (electric motor), such as the configuration in which the parking brake is applied, and the pressing force is As long as the brake mechanism can be held, the configuration may not be the brake mechanism of the above-described embodiment.

  Next, the parking brake control device 19 that controls the disc brake 31 using the electric actuator 43 will be described with reference to FIG.

  The parking brake control device 19 as a control device constitutes an electric brake system together with a pair of left and right disc brakes 31. The parking brake control device 19 has an arithmetic circuit (CPU) 20 configured by a microcomputer or the like, and the parking brake control device 19 is supplied with power from the battery 14 through the power supply line 15.

  The parking brake control device 19 controls the electric motor 43B of the disc brake 31 to generate a braking force (parking brake, auxiliary brake) when the vehicle is parked, stopped, or traveling. That is, the parking brake control device 19 drives (applies and releases) the disc brake 31 as a parking brake and an auxiliary brake by driving the electric motor 43B. For this purpose, as shown in FIGS. 1 to 3, the parking brake control device 19 has an input side connected to the parking brake switch 18 and an output side connected to the electric motor 43 </ b> B of the disc brake 31.

  The parking brake control device 19 is electrically operated on the basis of an operation request (apply request, release request) due to a driver's operation of the parking brake switch 18, an operation request based on a parking brake apply / release determination logic, and an operation request based on ABS control. The motor 43B is driven, and the disc brake 31 is applied (held) or released (released). At this time, in the disc brake 31, the piston 39 and the brake pad 33 are held or released by the pressing member holding mechanism (rotation linear motion conversion mechanism 40) based on the drive of the electric motor 43B.

  As shown in FIG. 3, the arithmetic circuit (CPU) 20 of the parking brake control device 19 includes a parking brake switch 18, a vehicle data bus 16, a voltage sensor unit 22, and a motor drive circuit in addition to a memory (storage unit) 21. 23, the current sensor unit 24 and the like are connected. From the vehicle data bus 16, various state quantities of the vehicle necessary for the control (operation) of the parking brake, that is, various vehicle information can be acquired.

  The vehicle information acquired from the vehicle data bus 16 may be acquired by directly connecting a sensor that detects the information to the parking brake control device 19 (the arithmetic circuit 20 thereof). The arithmetic circuit 20 of the parking brake control device 19 is configured such that an operation request based on the above-described determination logic or ABS control is input from another control device (for example, the control unit 13) connected to the vehicle data bus 16. May be. In this case, the determination of parking brake apply / release and the ABS control by the above-described determination logic can be performed by another control device, for example, the control unit 13, instead of the parking brake control device 19. That is, the control content of the parking brake control device 19 can be integrated into the control unit 13.

  The parking brake control device 19 includes a memory 21 including, for example, a flash memory, a ROM, a RAM, an EEPROM, and the like. The memory 21 stores a processing program for executing the processing flow of the dynamic parking brake shown in FIG. 4 in addition to the aforementioned parking brake apply / release determination logic and ABS control program. The memory 21 also stores various calculation formulas and coefficients (setting values for determining the vehicle speed, etc.) used in the dynamic parking brake processing program. The parking brake control device 19 includes a low-speed traveling state ABS control unit that performs ABS control in a low-speed traveling state and a high-speed traveling state ABS control unit that performs ABS control in a high-speed traveling state.

  In the embodiment, the parking brake control device 19 is separated from the control unit 13 of the ESC 11, but the parking brake control device 19 may be integrated with the control unit 13. The parking brake control device 19 controls the two disc brakes 31 on the left and right, but may be provided for each of the left and right disc brakes 31. In this case, the parking brake The control device 19 can also be provided integrally with the disc brake 31.

  When the parking brake switch 18 is braked ON, the parking brake control device 19 performs static control (static parking brake) and dynamic control (dynamic parking) on the disc brake 31 according to the state of the vehicle. Brake). Static control is performed when the parking brake switch 18 is braked ON while the vehicle is stopped. In this static control, for example, when the parking brake switch 18 is pulled up, the disc brake 31 generates a braking force for stopping the vehicle.

  On the other hand, the dynamic control is performed when the parking brake switch 18 is braked ON while the vehicle is traveling. In this dynamic control, for example, when the parking brake switch 18 is continuously raised, a braking force is gradually generated in the disc brake 31, and when the hand is released from the parking brake switch 18, the braking force of the disc brake 31 is released. is there.

  As shown in FIG. 3, the parking brake control device 19 includes a voltage sensor unit 22 that detects a voltage from the power supply line 15, and left and right motor drive circuits 23 that drive the left and right electric motors 43 </ b> B and 43 </ b> B, respectively. , 23, and left and right current sensor sections 24, 24 for detecting the respective motor currents of the left and right electric motors 43B, 43B. The voltage sensor unit 22, the motor drive circuit 23, and the current sensor unit 24 are connected to the arithmetic circuit 20, respectively.

  Thereby, in the arithmetic circuit 20 of the parking brake control device 19, when applying or releasing, the disc rotor 4 and the brake pad are based on the change of the motor current of the electric motor 43B detected by the current sensor units 24, 24. Determination of contact / separation with 33, determination of stoppage of driving of the electric motor 43B (apply completion determination, release completion determination) and the like can be performed.

  The electric brake system for a four-wheeled vehicle according to the embodiment has the above-described configuration. Next, the operation thereof will be described.

  When the driver of the vehicle depresses the brake pedal 6, the pedaling force is transmitted to the master cylinder 8 via the booster 7, and brake fluid pressure is generated by the master cylinder 8. The hydraulic pressure generated in the master cylinder 8 is distributed to the disc brakes 5 and 31 via the cylinder side hydraulic pipes 10A and 10B, the ESC 11 and the brake side pipe sections 12A, 12B, 12C and 12D, and left and right A braking force is applied to the front wheel 2 and the left and right rear wheels 3, respectively.

  A specific operation of the disc brake 31 for the rear wheel 3 at this time will be described. The hydraulic pressure is supplied into the cylinder portion 36 of the caliper 34 via the brake side piping portions 12C and 12D, and the piston 39 is slidably displaced toward the brake pad 33 on the inner side as the hydraulic pressure in the cylinder portion 36 increases. To do. Accordingly, the piston 39 presses the inner brake pad 33 against one side surface of the disk rotor 4. Due to the reaction force at this time, the entire caliper 34 is slidably displaced toward the inner side with respect to the respective arm portions of the mounting member 32.

  As a result, the outer leg portion (claw portion 38) of the caliper 34 operates so as to press the brake pad 33 on the outer side against the disc rotor 4, and the disc rotor 4 is moved in the axial direction by the pair of brake pads 33. It is clamped from both sides. Thereby, a braking force based on the hydraulic pressure is generated. On the other hand, when the brake operation is released, the supply of the hydraulic pressure into the cylinder portion 36 is stopped, so that the piston 39 is displaced so as to retract into the cylinder portion 36. As a result, the inner-side and outer-side brake pads 33 are separated from the disc rotor 4, and the vehicle is returned to the non-braking state.

  Next, when the driver operates the parking brake switch 18 to the braking side (on) (braking ON operation) while the vehicle is stopped, power is supplied from the parking brake control device 19 to the electric motor 43B of the disc brake 31. The output shaft 43C of the electric actuator 43 is rotationally driven. The disc brake 31 with the electric parking brake function converts the rotational motion of the electric actuator 43 into the linear motion of the linear motion member 42 via the screw member 41 of the rotational linear motion conversion mechanism 40, and the linear motion member 42 in the axial direction. The piston 39 is propelled by moving it. As a result, the pair of brake pads 33 are pressed against both surfaces of the disc rotor 4.

  At this time, the linear motion member 42 is held in a braking state by a frictional force (holding force) generated between the linear motion member 42 and the screw member 41 using the pressing reaction force transmitted from the piston 39 as a vertical reaction force. The disc brake 31 is operated (applied) as a parking brake. That is, even after power supply to the electric motor 43B is stopped, the linear motion member 42 (and hence the piston 39) is held in the braking position by the female screw of the linear motion member 42 and the male screw of the screw member 41.

  On the other hand, when the driver operates the parking brake switch 18 to the braking release side (off) (braking OFF operation), electric power is supplied from the parking brake control device 19 so as to reverse the motor to the electric motor 43B. The output shaft 43 </ b> C is rotated in the opposite direction to that when the parking brake is operated (during application). At this time, the holding of the braking force by the screw member 41 and the linear motion member 42 is released, and the rotation / linear motion conversion mechanism 40 moves the linear motion member 42 in the return direction by a movement amount corresponding to the reverse rotation amount of the electric actuator 43. That is, it is moved into the cylinder portion 36, and the braking force of the parking brake (disc brake 31) is released.

  By the way, when the vehicle is traveling, for example, when the brake pedal 6 is stuck, the booster 7 is broken, the hydraulic pressure (hydraulic pressure) is lost, etc., the service brake does not function sufficiently. At this time, when the driver operates the parking brake switch 18 to stop the vehicle (emergency stop), the electric actuator 43 can actuate the disc brake 31. In this case, when the vehicle is running and both the left and right rear wheels 3 are in the unlocked state, when the driver brakes the parking brake switch 18, the parking brake control device 19 As a dynamic parking brake control process, an emergency stop control process described later is performed.

  Hereinafter, the emergency stop control process performed by the parking brake control device 19 will be described with reference to FIG.

  Note that the process of FIG. 4 is repeatedly executed at predetermined time intervals (with a predetermined control cycle) while the parking brake control device 19 is energized. Further, in the above description, as an example of the start condition of the emergency stop control process, three conditions are given: that the vehicle is running, that both wheels are in an unlocked state, and that the parking brake switch 18 is braked ON. However, the present invention is not limited to this, and the condition of the two-wheel non-locking state may be omitted. That is, when the parking brake switch 18 is braked ON while the vehicle is running, the emergency stop control process may be started regardless of whether or not both wheels are unlocked.

  When the processing operation of FIG. 4 starts, the arithmetic circuit 20 determines whether or not the vehicle is traveling in S1. The determination as to whether or not the vehicle is traveling can be made based on, for example, the wheel speed or the vehicle speed acquired from the vehicle data bus 16.

  Whether or not the vehicle is running is determined by determining whether or not the accelerator pedal is operated, determining whether or not the clutch pedal is operated, and operating the shift lever other than P and N (neutral). It can also be performed in combination with the determination of whether or not.

  If “YES” in S1, that is, if it is determined that the vehicle is running, the process proceeds to S2. On the other hand, if “NO” in S1, that is, if it is determined that the vehicle is not in a running state (stopped state), the control returns from the dynamic control to the static control, and thus returns.

  In S2, it is determined whether or not there is an emergency stop control request. This determination can be made based on whether or not the driver is operating the parking brake switch 18 to turn on the brake. If “YES” in S2, that is, if it is determined that there is an emergency stop control request, the process proceeds to S3. On the other hand, if “NO” in S2, that is, if it is determined that there is no emergency stop control request, the process proceeds to S13.

  In S3, it is determined whether both the left and right brake devices (disc brake 31) are performing emergency stop control. This determination is made based on flags in S4, S11, and S12 described later. If “NO” in S3, that is, if both the left and right brake devices are not performing emergency stop control, or if either the left or right brake device is not performing emergency stop control, the process proceeds to S4. . On the other hand, if “YES” in S3, that is, if both the left and right brake devices are performing emergency stop control, the process proceeds to S5.

  In S4, emergency stop control is performed on both the left and right brake devices. Then, apply control is applied to both the left and right wheels. At this time, both the left and right brake devices set a flag indicating that emergency stop control is being performed.

  In S5, it is determined whether or not the left rear wheel 3 is slipping. This determination can be made based on, for example, a signal from a wheel speed sensor acquired from the vehicle data bus 16. As a specific example, whether or not the left rear wheel 3 is in a slip state can be determined based on whether or not the rotation of the left rear wheel 3 has decreased beyond a set deceleration. If “NO” in S5, that is, if the left rear wheel 3 is determined to be in a non-slip state, the process proceeds to S7. On the other hand, if “YES” in S5, that is, if it is determined that the left rear wheel 3 is in the slip state, the process proceeds to S6. In next S6, in order to put the disc brake 31 of the left rear wheel 3 in the slip state into the released state, the emergency brake release permission (set flag) is given to the disc brake 31 of the left rear wheel 3, and the next Proceed to S7.

  In S7, it is determined whether or not the right rear wheel 3 is slipping. This determination can be made based on, for example, a signal from a wheel speed sensor acquired from the vehicle data bus 16 as in S5. If “NO” in S7, that is, if it is determined that the right rear wheel 3 is in the non-slip state, the process proceeds to S9. On the other hand, if “YES” in S7, that is, if it is determined that the right rear wheel 3 is in the slip state, the process proceeds to S8. In the next S8, in order to put the disc brake 31 of the right rear wheel 3 in the slip state into the released state, the emergency brake release permission (set flag) is given to the disc brake 31 of the right rear wheel 3, and the next Proceed to S9.

  In S9, it is determined whether the emergency stop release is not permitted for both the left and the right. If “YES” in S9, that is, if the emergency stop release is not permitted for both the left and right disc brakes 31, the process returns as it is in order to continue the applied state or the braking force holding state.

  On the other hand, if “NO” in S9, that is, if the emergency stop release is permitted in at least one of the left and right disc brakes 31, the process proceeds to S10 to determine whether or not the vehicle body speed is less than the set value. To do. This determination is made based on, for example, a signal from a vehicle speed sensor acquired from the vehicle data bus 16. The set value is a speed threshold value as a predetermined value for determining whether the vehicle is in a high speed driving state or a low speed driving state, and is set to about 60 km / h, for example. The set value for determining the vehicle body speed is not limited to the above-mentioned value, but is set as appropriate according to the specification of the vehicle.

  If “YES” in S10, that is, if it is determined that the vehicle speed is less than the set value, the process proceeds to S11. In this case, the apply request signal is output while the vehicle is traveling at a low speed. For this reason, in S11, the parking brake control device 19 independently performs antilock control on the left and right disc brakes 31. Specifically, the parking brake control device 19 puts the disc brake 31 of which emergency stop cancellation is permitted in S5 (S6) and S7 (S8) out of the left and right disc brakes 31 into a released state. On the other hand, the parking brake control device 19 sets the disc brake 31 of which the emergency stop release is not permitted in S5 (S6) and S7 (S8) out of the left and right disc brakes 31 as the non-released state, the applied state or the control state. Continue holding power.

  As a result, the parking brake control device 19 allows the disc brake of one rear wheel 3 (for example, the left rear wheel 3) in the slip state when one of the left and right rear wheels 3 is in the slip state. The electric actuator 43 of the left disc brake 31 and the right disc are arranged so that the disc brake 31 of the other rear wheel 3 (for example, the right rear wheel 3) in the non-slip state is brought into a non-release state. The electric actuator 43 of the brake 31 is controlled. For this reason, S1, S5 to S8, S10, and S11 show specific examples of the low-speed traveling state ABS control unit that performs anti-lock control in the low-speed traveling state of the vehicle. And in S11, the flag used by determination of S3 that emergency stop control is being implemented only for one wheel is raised.

  On the other hand, if “NO” in S10, that is, if the vehicle speed is not less than the set value and it is determined that the vehicle speed is greater than or equal to the set value, the process proceeds to S12, and both the left and right disc brakes 31 are put into the released state. In this case, an apply request signal is output while the vehicle is traveling at a high speed, and one of the left and right rear wheels 3 is in a slip state. For this reason, in S12, the parking brake control device 19 performs antilock control on the left and right disc brakes 31 together. Specifically, among the left and right disc brakes 31, when there is a disc brake 31 whose emergency stop release is permitted in S5 (S6) and S7 (S8), both the left and right disc brakes 31 are released. Put it in a state.

  As a result, the parking brake control device 19 allows the left and right disc brakes 31 to be in the released state when either one of the left or right rear wheels 3 is in the slip state. The electric actuator 43 of the brake 31 and the electric actuator 43 of the right disc brake 31 are controlled. For this reason, S1, S5 to S8, S10, and S12 show specific examples of the high-speed running state ABS control unit that performs anti-lock control in a high-speed running state of the vehicle. In S12, a flag used in the determination in S3 that both wheels of the left and right brake devices are not performing emergency stop control is set.

  If “NO” in S2, that is, if it is determined that there is no emergency stop control request, the process proceeds to S13. In S13, it is determined whether emergency stop control is being performed. This determination is made based on the flags in S4, S11, and S12.

  If “NO” in S13, that is, if it is determined that the emergency stop control is not being performed, the process returns. If “YES” in S13, that is, if it is determined that emergency stop control is being performed, the process proceeds to S14. In S14, there is no emergency stop control request, but the emergency stop control is being executed. Therefore, this execution is stopped, the emergency stop control of both the left and right brake devices is canceled, and the process returns.

  Thus, according to the present embodiment, when the vehicle is running at a low speed and there is an apply request signal, the parking brake control device 19 independently performs antilock control on the left and right disc brakes 31. In other words, when the vehicle speed is less than the predetermined value and the brake device is operated in response to the braking request signal, and the first wheel on the left or right slips, The release control is performed, and the release control is not performed for the second wheel of the left and right. For this reason, when the vehicle is running at a low speed and there is an apply request signal, the parking brake control device 19 is in a slip state when one of the left and right rear wheels 3 is in a slip state. The electric actuator 43 of the left disc brake 31 and the right disc brake 31 are arranged so that the disc brake 31 of one wheel is in the released state and the disc brake 31 of the other wheel in the non-slip state is in the non-released state. The electric actuator 43 is controlled. As a result, since the braking force can be applied to the other wheel in the non-slip state by the disc brake 31, the braking distance of the vehicle can be shortened.

  On the other hand, for example, when the braking force (braking force) is removed only by one rear wheel 3 by anti-lock control, only the braking force of the other rear wheel 3 is applied, and a yaw moment is generated in the vehicle. When this yaw moment is generated while the vehicle is traveling at high speed, the vehicle tends to become unstable.

  On the other hand, in this embodiment, when the vehicle is in a high-speed running state and there is an apply request signal, the parking brake control device 19 performs antilock control on the left and right disc brakes 31 together. In other words, when the vehicle speed is equal to or higher than the predetermined value and the brake device is operated in response to the braking request signal, and the first wheel of the left or right slips, The release control is also performed, and the release control is also performed for the second wheel of the left and right. For this reason, when the vehicle is in a high-speed running state and there is an apply request signal, the parking brake control device 19 detects when the left and right rear wheels 3 are in a slip state and the left and right The electric actuator 43 of the left disc brake 31 and the electric actuator 43 of the right disc brake 31 are controlled so that both of the disc brakes 31 are in the released state. As a result, the anti-lock control by the dynamic parking brake can suppress the yaw moment generated in the vehicle even when only one wheel slips during high-speed traveling, and can ensure the stability of the vehicle.

  The apply operation and the release operation of the dynamic parking brake will be described. When the vehicle is running, the parking brake control device 19 applies the left and right disc brakes 31 at the same timing (same timing) according to the apply request signal. ). That is, the parking brake control device 19 is connected to the electric actuator 43 of the left disc brake 31 so that the left and right disc brakes 31 are applied at the same timing when the apply request signal is output while the vehicle is running. The electric actuator 43 of the right disc brake 31 is controlled. Similarly, the parking brake control device 19 releases the left and right disc brakes 31 at the same timing when the output of the apply request signal is stopped while the vehicle is running or when the release request signal is output. Thus, the electric actuator 43 of the left disc brake 31 and the electric actuator 43 of the right disc brake 31 are controlled. As a result, the left and right disc brakes 31 perform the apply operation and the release operation at substantially the same timing, so that it is possible to suppress the deviation of the braking force on the left and right and to ensure the stability of the vehicle.

  On the other hand, the apply operation and release operation of the static parking brake will be described. The parking brake control device 19 operates the left and right disc brakes 31 at different timings according to the apply request signal when the vehicle is stopped. That is, the parking brake control device 19 is connected to the electric actuator 43 of the left disc brake 31 so that the left and right disc brakes 31 are applied at different timings when an apply request signal is output when the vehicle is stopped. The electric actuator 43 of the right disc brake 31 is controlled. Similarly, when the vehicle is stopped and the release request signal is output, the parking brake control device 19 releases the left and right disc brakes 31 at different timings so that the electric actuator 43 of the left disc brake 31 is operated. And the electric actuator 43 of the right disc brake 31 are controlled. Thereby, the inrush current when starting the electric actuator 43 can be generated at different timings on the left and right, and the load on the battery 14 and the like can be reduced.

  In the above-described embodiment, the parking brake switch 18 has been described as an example in which the raising operation is the braking ON operation and the depression operation is the braking OFF operation. However, the present invention is not limited to this. For example, the parking brake switch may be configured such that the pushing operation is a braking ON operation and the pulling operation is a braking OFF operation. Specific modes of the braking ON operation and the braking OFF operation are appropriately set according to the vehicle specifications and the like.

  In the embodiment described above, the case where the left and right rear wheel side brakes are the disc brakes 31 with the electric parking brake function has been described as an example. However, the present invention is not limited to this. For example, the left and right front wheel brakes may be disc brakes with an electric parking brake function, and the brakes of all wheels (all four wheels) are constituted by disc brakes with an electric parking brake function. May be. That is, the brake of at least a pair of wheels of the vehicle can be configured by a disc brake with an electric parking brake function.

  In the embodiment described above, the hydraulic disc brake 31 with an electric parking brake has been described as an example. However, the present invention is not limited to this. For example, an electric disc brake that does not require supply of hydraulic pressure may be used. Further, the present invention is not limited to the disc brake type brake device, and may be configured as, for example, a drum brake type brake device. Further, for example, the brake device may be constituted by a drum-in disc brake in which a drum type electric parking brake is provided on the disc brake, or may be a brake device that holds the parking brake by pulling a cable with an electric motor. Various devices can be adopted. In this case, for example, when an electric brake mechanism that does not require supply of hydraulic pressure is employed, the control device applies a braking force to the vehicle as a service brake (based on an apply request by operating a brake pedal or the like) (A motor is driven).

2 Front wheels
3 Rear wheels
4 Disc rotor (rotating member)
6 Brake pedal 18 Parking brake switch 19 Parking brake control device (control device)
31 Disc brake (brake device)
33 Brake pads (friction members)
39 Piston 43 Electric actuator (Electric mechanism)

Claims (4)

A brake that propels a piston that presses the friction member against the rotating member that rotates with the wheel, and that also holds the pressing force of the friction member by pressing the friction member against the rotating member by an electric mechanism in response to a braking request signal At least a pair of devices are provided on the left and right sides of the vehicle,
A control device for controlling the electric mechanism of each brake device,
The controller is
When operating the brake device in response to the braking request signal when the vehicle is running at a low speed, the left and right brake devices are independently anti-lock controlled,
The electric brake is characterized in that when the vehicle operates the brake device in response to the braking request signal in a high-speed driving state at a speed higher than the low-speed driving state, the left and right brake devices are anti-lock controlled together. system.   When the vehicle operates the brake device in response to the braking request signal in the high speed traveling state, the control device is configured such that when at least one of the left and right wheels is slipped, 2. The electric brake system according to claim 1, wherein the electric mechanisms of the left and right brake devices are controlled such that both the right brake devices are in a released state.   When the vehicle operates the brake device in response to the braking request signal in the low-speed traveling state, the control device sets the slip state when one of the left and right wheels is slipped. 2. The electric mechanism of the left and right brake devices is controlled so that the brake device of the one wheel that has become the release state and the brake device of the other wheel that has become the non-slip state become the non-release state. Or the electric brake system of 2. A brake that propels a piston that presses the friction member against the rotating member that rotates with the wheel, and that also holds the pressing force of the friction member by pressing the friction member against the rotating member by an electric mechanism in response to a braking request signal At least a pair of devices are provided on the left and right sides of the vehicle,
A control device for controlling the electric mechanism of each brake device,
The controller is
When the vehicle speed is less than a predetermined value and the brake device is operated in response to the braking request signal, and the first wheel of the left or right slips, While performing release control, it does not perform release control for the second wheel of the left and right,
When the vehicle speed is equal to or higher than a predetermined value and the brake device is operated in response to the braking request signal, and the first wheel of the left and right slips, An electric brake system that performs release control and also performs release control for the second wheel of the left and right.

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