JP2020001632A - Braking control device - Google Patents

Abstract

To provide a braking control device that achieves electric braking force with high control accuracy.SOLUTION: The invention relates to a braking control device which comprises, for example: a hydraulic brake device for pressing a braking member with hydraulic pressure against a braking target member which rotates integrally with a wheel, thus generating hydraulic braking force; and an electric brake device for pressing the braking member by driving a motor toward the braking target member to generate electric braking force. The brake control device further comprises: a hydraulic brake control unit for controlling the hydraulic brake device; and an electric brake control unit for controlling the electric brake device on the basis of a driving property value being a detection value related to a driving property of the electric brake device. The hydraulic brake control unit generates a prescribed hydraulic pressure by controlling the hydraulic brake device. The electric brake control unit drives the electric brake device in a state in which the prescribed hydraulic pressure is being generated, and detects the driving property value of the electric brake device with respect to the prescribed hydraulic pressure.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a braking control device.

  2. Description of the Related Art In recent years, electric parking brakes (hereinafter referred to as EPBs (Electric Parking Brakes) or electric brake devices) are widely used in various vehicles such as passenger cars. A braking control device that controls the EPB generates an electric braking force by driving a wheel brake mechanism with a motor, for example.

  Further, the EPB can be used not only when the vehicle is stopped but also when the vehicle is running. The scenes in which the EPB is used when the vehicle is running include, for example, an emergency, an automatic operation, and a failure of a hydraulic brake. When the EPB is used when the vehicle is running, high control accuracy is required.

  In EPB, braking control is performed based on driving characteristics. As the driving characteristics, for example, a relationship between a motor current value and an electric braking force, a relationship between a physical quantity (for example, motor rotation speed) related to a stroke amount of a propulsion shaft in EPB and an electric braking force, and the like are considered.

JP 2012-96793 A

  However, since the above-mentioned drive characteristics differ depending on individual differences of components of the brake, aging, environmental temperature, and the like, in the related art, the control accuracy of the electric braking force may be reduced.

  Therefore, one of the objects of the present invention is to provide, for example, a braking control device that realizes an electric braking force with high control accuracy.

  The present invention provides, for example, a hydraulic brake device that generates a hydraulic braking force by pressing a braking member by hydraulic pressure toward a braked member that rotates integrally with a wheel, and a motor that moves toward the braked member. And an electric brake device for generating an electric braking force by driving the brake member to generate an electric braking force, wherein the hydraulic brake control device controls the hydraulic brake device. And an electric brake control unit that controls the electric brake device based on a drive characteristic value that is a detected value related to a drive characteristic of the electric brake device. The hydraulic brake control unit generates a predetermined hydraulic pressure by controlling the hydraulic brake device, and the electric brake control unit drives the electric brake device in a state where the predetermined hydraulic pressure is generated. Detecting the drive characteristic value of the electric brake device with respect to the predetermined hydraulic pressure.

  In the above-described brake control device, for example, the electric brake control unit drives the electric brake device in a state where the predetermined hydraulic pressure is generated to move a propulsion shaft toward the member to be braked so that a piston Then, after the hydraulic pressure is reduced to zero by the control of the hydraulic brake device by the hydraulic brake control unit, control is performed to move the propulsion shaft to the side facing the member to be braked. The current value of the motor at this time is detected as the drive characteristic value.

  In the above-described brake control device, for example, the electric brake control unit drives the electric brake device in a state where the predetermined hydraulic pressure is generated to move a propulsion shaft from a predetermined position to the braked member side. Then, the stroke amount of the propulsion shaft when it is brought into contact with the piston is detected as the drive characteristic value.

  Further, in the above-described brake control device, for example, the hydraulic brake control unit generates a plurality of stepwise hydraulic pressures as the predetermined hydraulic pressure, and the electric brake control unit performs a process for each of the hydraulic pressures. The drive characteristic value of the electric brake device is detected.

FIG. 1 is a schematic diagram illustrating an overall outline of a vehicle brake device according to a first embodiment. FIG. 2 is a schematic cross-sectional view of a rear wheel system wheel brake mechanism provided in the vehicle brake device of the first embodiment. FIG. 3 is a graph showing how the W / C pressure and the like change over time when the characteristic information is corrected in the first embodiment. FIG. 4 is a graph showing characteristic information according to the first embodiment. FIG. 5 is a flowchart illustrating a process performed by the braking control device according to the first embodiment. FIG. 6 is a graph showing how the W / C pressure and the like change over time when the characteristic information is corrected in the second embodiment. FIG. 7 is a graph showing characteristic information according to the second embodiment. FIG. 8 is a flowchart illustrating a process performed by the braking control device according to the second embodiment.

  Hereinafter, exemplary embodiments (Embodiments 1 and 2) of the present invention will be disclosed. The configuration of the embodiment described below, and the operation and result (effect) provided by the configuration are examples. The present invention can be realized by configurations other than those disclosed in the following embodiments. Further, according to the present invention, at least one of various effects (including derivative effects) obtained by the following configuration can be obtained.

(1st Embodiment)
In the first embodiment, a vehicle brake device in which a disc brake type EPB is applied to a rear wheel system will be described as an example. FIG. 1 is a schematic diagram illustrating an overall outline of a vehicle brake device according to a first embodiment. FIG. 2 is a schematic cross-sectional view of a rear wheel system wheel brake mechanism provided in the vehicle brake device of the first embodiment. Hereinafter, description will be made with reference to these drawings.

  As shown in FIG. 1, the vehicle brake device according to the first embodiment includes a service brake 1 (a hydraulic brake device) and an EPB 2 (an electric brake device).

  The service brake 1 is directed to a member to be braked (the brake disc 12 in FIG. 2) that rotates integrally with the wheels based on the depression of the brake pedal 3 by the driver, and the braking member (the brake pad 11 in FIG. ) To generate a service braking force (hydraulic braking force). Specifically, the service brake 1 boosts the pedaling force according to the depression of the brake pedal 3 by the driver with the booster 4, and then applies the brake fluid pressure according to the boosted pedaling force to the master cylinder ( Hereinafter, it is referred to as M / C.) Then, a service brake force is generated by transmitting the brake fluid pressure to a wheel cylinder (hereinafter, referred to as W / C) 6 provided in a wheel brake mechanism of each wheel. Further, an actuator 7 for controlling brake fluid pressure is provided between the M / C 5 and the W / C 6. The actuator 7 performs various controls (for example, anti-skid control and the like) for adjusting the service brake force generated by the service brake 1 and improving the safety of the vehicle.

  Various controls using the actuator 7 are executed by an ESC (Electronic Stability Control) -ECU 8 (braking control device; hydraulic brake control unit) for controlling the service braking force. For example, the ESC-ECU 8 outputs a control current for controlling various control valves and a pump driving motor (not shown) provided in the actuator 7, thereby controlling a hydraulic circuit provided in the actuator 7 and the W / C 6. Control the W / C pressure transmitted to the motor. This avoids wheel slips and improves the safety of the vehicle.

  For example, the actuator 7 controls, for each wheel, a pressure increase control that controls the application of the brake fluid pressure generated in the M / C 5 or the brake fluid pressure generated by driving the pump to the W / C 6. A valve and a pressure reduction control valve that reduces the W / C pressure by supplying the brake fluid in each W / C 6 to the reservoir are provided so that the W / C pressure can be increased, maintained, and reduced. ing. Further, the actuator 7 can realize the automatic pressurizing function of the service brake 1, and automatically applies the W / C 6 based on the driving of the pump and the control of various control valves even when there is no brake operation. Can be pressed.

  On the other hand, the EPB 2 generates an electric braking force by driving a wheel brake mechanism by the motor 10, and has an EPB-ECU 9 (braking control device; electric brake control unit) for controlling the driving of the motor 10. It is configured. Specifically, for example, the EPB 2 drives the motor 10 toward the member to be braked (the brake disk 12 in FIG. 2) so that the vehicle does not move unintentionally during parking, and thereby the braking member (in FIG. 2). By pressing the brake pad 11), an electric braking force is generated. Note that the EPB-ECU 9 and the ESC-ECU 8 transmit and receive information by, for example, CAN (Controller Area Network) communication.

  The wheel brake mechanism is a mechanical structure that generates a braking force in the vehicle brake device of the first embodiment. First, the front wheel system wheel brake mechanism is configured to generate a service brake force by operating the service brake 1. ing. On the other hand, the wheel brake mechanism of the rear wheel system has a common structure that generates a braking force for both the operation of the service brake 1 and the operation of the EPB 2. The front wheel brake mechanism is a generally used wheel brake mechanism which eliminates a mechanism for generating an electric braking force based on the operation of the EPB 2 with respect to the rear wheel brake mechanism. The description is omitted here, and the rear wheel system wheel brake mechanism will be described below.

  In the rear wheel brake mechanism, not only when the service brake 1 is operated but also when the EPB 2 is operated, the brake pad 11 which is a friction material shown in FIG. By sandwiching the brake disk 12 (12RL, 12RR, 12FR, 12FL), which is a material, a frictional force is generated between the brake pad 11 and the brake disk 12, thereby generating a braking force.

  Specifically, the wheel brake mechanism rotates the motor 10 directly fixed to the body 14 of the W / C 6 for pressing the brake pad 11 as shown in FIG. 2 in the caliper 13 shown in FIG. Thus, the spur gear 15 provided on the drive shaft 10a of the motor 10 is rotated. Then, the brake pad 11 is moved by transmitting the rotational force (output) of the motor 10 to the spur gear 16 meshed with the spur gear 15 to generate the electric braking force by the EPB 2.

  In the caliper 13, in addition to the W / C 6 and the brake pad 11, a part of the end face of the brake disc 12 is housed so as to be sandwiched by the brake pad 11. The W / C 6 can generate a W / C pressure in the hollow portion 14a that is the brake fluid storage chamber by introducing the brake fluid pressure into the hollow portion 14a of the cylindrical body 14 through the passage 14b. The rotary shaft 17, the propulsion shaft 18, the piston 19 and the like are provided in the hollow portion 14 a.

  One end of the rotation shaft 17 is connected to the spur gear 16 through an insertion hole 14 c formed in the body 14, and when the spur gear 16 is rotated, the rotation shaft 17 is rotated with the rotation of the spur gear 16. At the end of the rotating shaft 17 opposite to the end connected to the spur gear 16, a male screw groove 17 a is formed on the outer peripheral surface of the rotating shaft 17. On the other hand, the other end of the rotating shaft 17 is supported by being inserted into the insertion hole 14c. Specifically, the insertion hole 14c is provided with a bearing 21 together with the O-ring 20, so that the O-ring 20 prevents the brake fluid from leaking through between the rotating shaft 17 and the inner wall surface of the insertion hole 14c. The other end of the rotating shaft 17 is supported by the bearing 21 while being rotated.

  The propulsion shaft 18 is formed of a nut made of a hollow cylindrical member, and has a female screw groove 18a formed on an inner wall surface thereof so as to screw with the male screw groove 17a of the rotary shaft 17. The propulsion shaft 18 is formed, for example, in a cylindrical or polygonal shape having a key for preventing rotation, so that the propulsion shaft 18 can be rotated about the rotation center of the rotation shaft 17 even if the rotation shaft 17 rotates. There is no structure. Therefore, when the rotary shaft 17 is rotated, the rotational force of the rotary shaft 17 is reduced to a force for moving the propulsion shaft 18 in the axial direction of the rotary shaft 17 due to the engagement between the male screw groove 17a and the female screw groove 18a. Convert. When the drive of the motor 10 is stopped, the propulsion shaft 18 stops at the same position due to the frictional force generated by the engagement between the male screw groove 17a and the female screw groove 18a, and the propulsion shaft 18 reaches the target electric braking force. When the driving of the motor 10 is stopped at this time, the propulsion shaft 18 is held at that position, and the self-locking (hereinafter simply referred to as “locking”) can be performed while holding the desired electric braking force.

  The piston 19 is arranged so as to surround the outer periphery of the propulsion shaft 18, and is formed of a bottomed cylindrical member or a polygonal cylindrical member, and the outer peripheral surface is in contact with the inner wall surface of the hollow portion 14 a formed in the body 14. Are arranged as follows. A seal member 22 is provided on the inner wall surface of the body 14 to apply a W / C pressure to the end surface of the piston 19 so that the brake fluid does not leak between the outer peripheral surface of the piston 19 and the inner wall surface of the body 14. It has been. The seal member 22 is used to generate a reaction force for pulling back the piston 19 during release control after lock control. Since the seal member 22 is provided, basically, even if the brake pad 11 and the piston 19 are pushed by the brake disc 12 that is inclined during turning within a range that does not exceed the elastic deformation amount of the seal member 22, they are braked. By pushing back to the disc 12 side, the space between the brake disc 12 and the brake pad 11 can be maintained at a predetermined clearance (clearance C2 in FIG. 2).

  When the propulsion shaft 18 is provided with a key for preventing rotation so that the piston 19 is not rotated about the rotation center of the rotation shaft 17 even when the rotation shaft 17 rotates, the key is When a sliding key groove is provided, and the propulsion shaft 18 has a polygonal column shape, the propulsion shaft 18 has a corresponding polygonal cylindrical shape.

  The brake pad 11 is arranged at the tip of the piston 19, and moves the brake pad 11 in the left-right direction on the paper as the piston 19 moves. Specifically, the piston 19 is movable to the left in the drawing with the movement of the propulsion shaft 18, and is attached to an end of the piston 19 (an end opposite to the end on which the brake pad 11 is arranged). By applying the W / C pressure, it is configured to be able to move leftward on the paper independently of the propulsion shaft 18. When the propulsion shaft 18 is in a release position (a state before the motor 10 is rotated), which is a standby position when the normal release is performed, a state in which the brake fluid pressure in the hollow portion 14a is not applied (W / C). If (pressure = 0), the piston 19 is moved rightward on the paper by the elastic force of the seal member 22 described later, and the brake pad 11 is separated from the brake disk 12.

  When the motor 10 is rotated and the propulsion shaft 18 is moved leftward from the initial position on the paper, even if the W / C pressure becomes zero, the piston 19 is moved rightward on the paper by the moved propulsion shaft 18 even if the W / C pressure becomes zero. Is restricted, and the brake pad 11 is held at that location. The clearance C1 in FIG. 2 indicates the distance between the tip of the propulsion shaft 18 and the piston 19. After the release of the EPB is completed, the position of the propulsion shaft 18 is fixed to the body 14.

  In the wheel brake mechanism configured as described above, when the service brake 1 is operated, the piston 19 is moved leftward on the paper on the basis of the W / C pressure generated by the service brake 1, so that the brake pad 11 brakes. It is pressed by the disk 12 to generate a service brake force. When the EPB 2 is operated, the motor 10 is driven to rotate the spur gear 15, and the spur gear 16 and the rotating shaft 17 are rotated accordingly, so that the male screw groove 17 a and the female screw groove 18 a The propulsion shaft 18 is moved toward the brake disk 12 (to the left in the drawing) based on the meshing of. Then, along with this, the tip of the propulsion shaft 18 comes into contact with the piston 19 and presses the piston 19, and the piston 19 is also moved in the same direction, whereby the brake pad 11 is pressed by the brake disc 12 and the electric braking force is generated. Let it. Therefore, it is possible to use a common wheel brake mechanism that generates a braking force for both the operation of the service brake 1 and the operation of the EPB 2.

  In the vehicle brake device according to the first embodiment, the state of generation of the electric braking force by the EPB 2 is checked by checking the current detection value by a current sensor (not shown) that detects the current of the motor 10. The current detection value can be recognized.

  The front-rear G sensor 25 detects a G (acceleration) in the front-rear direction (traveling direction) of the vehicle, and transmits a detection signal to the EPB-ECU 9.

  M / C pressure sensor 26 detects the M / C pressure at M / C 5 and transmits a detection signal to EPB-ECU 9.

  Temperature sensor 28 detects the temperature of a wheel brake mechanism (for example, a brake disk) and transmits a detection signal to EPB-ECU 9.

  The wheel speed sensor 29 detects the rotation speed of each wheel, and transmits a detection signal to the EPB-ECU 9. It should be noted that the wheel speed sensors 29 are actually provided one by one corresponding to each wheel, but detailed illustration and description are omitted here.

  The EPB-ECU 9 is configured by a well-known microcomputer having a CPU, a ROM, a RAM, an I / O, etc., and performs parking brake control by controlling the rotation of the motor 10 according to a program stored in the ROM or the like. It is.

  The EPB-ECU 9 inputs, for example, a signal corresponding to the operation state of an operation switch (switch) 23 provided on an instrument panel (not shown) in the vehicle compartment, and controls the motor 10 according to the operation state of the operation switch 23. Drive. Further, the EPB-ECU 9 executes lock control, release control, and the like based on the detected current value of the motor 10. Based on the control state, the EPB-ECU 9 performs lock control or performs wheel control in a locked state. It recognizes that there is, and that the wheels are in a release state (EPB release state) by release control or by release control. Then, the EPB-ECU 9 outputs a signal for causing the display lamp 24 provided on the instrument panel to perform various displays.

  The vehicle brake device configured as described above basically performs an operation of generating a braking force on the vehicle by generating a service braking force by the service brake 1 during traveling of the vehicle. Further, when the vehicle is stopped by the service brake 1, the driver presses the operation SW 23 to activate the EPB 2 to generate an electric braking force, thereby maintaining the stopped state, and thereafter releasing the electric braking force. Or the action of That is, as the operation of the service brake 1, when the driver operates the brake pedal 3 while the vehicle is running, the brake fluid pressure generated in the M / C 5 is transmitted to the W / C 6 to generate the service brake force. . The operation of the EPB 2 includes driving the motor 10 to move the piston 19, and pressing the brake pad 11 against the brake disc 12 to generate an electric braking force to lock the wheels or to lock the brake pad 11. By releasing the brake disk 12, the electric braking force is released and the wheels are released.

  Specifically, the electric braking force is generated or released by the lock / release control. In the lock control, the EPB 2 is operated by rotating the motor 10 forward, and the rotation of the motor 10 is stopped at a position where a desired electric braking force can be generated by the EPB 2, and this state is maintained. Thereby, a desired electric braking force is generated. In the release control, the EPB 2 is operated by rotating the motor 10 in the reverse direction to release the electric braking force generated by the EPB 2.

  Further, even when the vehicle is running, there are situations where it is effective to use the EPB2, for example, in an emergency, at the time of automatic driving, at the time of failure of the service brake 1, and the like. Is also good. When the EPB 2 is used during traveling of the vehicle, high control accuracy of the EPB 2 is required. In other words, if the control accuracy of the EPB 2 is low, an error occurs between the planned stop position and the actual stop position when the EPB is used while the vehicle is running.

  Further, the EPB-ECU 9 controls the EPB 2 based on characteristic information (drive characteristic value) which is information (detection value) on the drive characteristic of the EPB 2. The drive characteristics include, for example, a relationship between a motor current value and an electric braking force, and a relationship between a physical quantity (for example, a motor rotation speed) related to a stroke amount of the propulsion shaft 18 in the EPB 2 and an electric braking force. The characteristic information may be stored in the form of, for example, a map, a table, a mathematical expression, or the like.

  Further, in the EPB 2, by arranging a plurality of gears between the motor 10 and the propulsion shaft 18, the rotation speed is reduced every time the torque of the motor 10 is transmitted through the gears, thereby securing the output torque. . The sliding resistance varies depending on individual differences among components such as a plurality of gears, aging, environmental temperature, and the like. The difference in the sliding resistance means that the drive characteristics are different, and in the related art, the control accuracy of the electric braking force may be reduced. Therefore, in the first embodiment, an electric braking force with high control accuracy is realized by the following method.

  First, the ESC-ECU 8 generates a predetermined hydraulic pressure by controlling the service brake 1. Further, the EPB-ECU 9 drives the EPB 2 in a state where the predetermined hydraulic pressure is generated, and detects a driving characteristic value of the EPB 2 with respect to the predetermined hydraulic pressure (corrects the characteristic information).

  More specifically, the EPB-ECU 9 drives the EPB 2 in a state where the predetermined hydraulic pressure is generated to move the propulsion shaft 18 to the brake disk 12 side to contact the piston 19, and thereafter, the ESC-ECU 8 After the hydraulic pressure is reduced to zero by the control of the service brake 1 according to the above, the current value of the motor 10 when the control for moving the propulsion shaft 18 to the side facing the brake disk 12 is detected as the drive characteristic value ( Correct the characteristic information).

  Further, when the ESC-ECU 8 generates a plurality of stepwise hydraulic pressures as the predetermined hydraulic pressure, the EPB-ECU 9 detects the drive characteristic value of the EPB 2 for each of the plurality of hydraulic pressures (corrects the characteristic information).

  Hereinafter, the correction of the characteristic information will be described in detail with reference to FIGS. FIG. 3 is a graph showing how the W / C pressure and the like change over time when the characteristic information is corrected in the first embodiment. In the graph of FIG. 3A, the vertical axis represents the W / C pressure (MPa), and the horizontal axis represents time (ms). In the graph of FIG. 3B, the vertical axis represents the detected current value (A) of the motor 10 (hereinafter sometimes simply referred to as “current value”), and the horizontal axis represents time (ms). . In the graph of FIG. 3C, the vertical axis represents the braking force (N (Newton)), and the horizontal axis represents time (ms).

  FIG. 4 is a graph showing characteristic information according to the first embodiment. In the graph of FIG. 4, the vertical axis represents the current detection value (A) of the motor 10, and the horizontal axis represents the W / C pressure (MPa). FIG. 5 is a flowchart illustrating a process performed by the braking control device according to the first embodiment. The following processing is started, for example, in response to an operation of the operation SW 23 by the user when the vehicle stops.

  First, the ESC-ECU 8 generates a predetermined hydraulic pressure by controlling the service brake 1 (step S1 in FIG. 5). At this time, the W / C pressure (FIG. 3A) starts increasing at time t1, and reaches a predetermined hydraulic pressure (P) at time t2. Further, the braking force (FIG. 3 (c)) increases from time t1 to time t2 accordingly.

  Next, the EPB-ECU 9 drives the EPB 2 while the predetermined hydraulic pressure is being generated to move the propulsion shaft 18 toward the brake disk 12 and abut the piston 19 (step S2 in FIG. 5). At this time, at time t3 when the driving of the motor 10 is started, the current value (FIG. 3B) sharply increases due to the rush current, and after the current value stabilizes, the propulsion shaft 18 comes into contact with the piston 19. (That is, the clearance C1 in FIG. 2 has become zero), the current value increases from time t4 to time t5.

  Next, the hydraulic pressure is reduced to zero by controlling the service brake 1 by the ESC-ECU 8 (step S3 in FIG. 5). At this time, the W / C pressure (FIG. 3A) starts to decrease at time t6 and becomes zero at time t7. On the other hand, since the propulsion shaft 18 is in contact with the piston 19, the braking force (FIG. 3C) decreases only slightly.

  Next, the EPB-ECU 9 executes control to drive the EPB 2 to move the propulsion shaft 18 to the side facing the brake disk 12 (Step S4 in FIG. 5). At this time, the current value (FIG. 3B) sharply increases due to the rush current at time t8 when the driving of the motor 10 is started, and thereafter, the EPB-ECU 9 determines that the influence of the rush current has disappeared at time t9. The current detection value I is obtained (Step S5 in FIG. 5). Further, the current value (FIG. 3B) and the braking force (FIG. 3C) decrease from time t9 to time t10.

  Next, the EPB-ECU 9 corrects the characteristic information (FIG. 4) based on the predetermined hydraulic pressure (P) and the detected current value I of the motor 10 obtained in step S5.

  As described above, according to the first embodiment, the EPB-ECU 9 corrects the characteristic information based on the current driving characteristics in consideration of the individual differences of the components of the brake, the aging deterioration, the environmental temperature, and the like. An electric braking force with control accuracy can be realized.

  Further, a plurality of stepwise hydraulic pressures are set as the predetermined hydraulic pressure (P in FIG. 3A), and the EPB-ECU 9 sets the drive characteristic value (current value) of the EPB 2 for each of the plurality of hydraulic pressures. If the characteristic information is corrected based on this, control accuracy can be further improved.

  Note that, in general, the components of the EPB-ECU 9 and the brakes are handled separately before assembling the vehicle. Therefore, the calibration relating to the control of the EPB 2 by the EPB-ECU 9 cannot be executed until the assembly of the vehicle is completed. However, according to the first embodiment, after the vehicle assembly is completed, the electric braking force with high control accuracy is realized by correcting the characteristic information as described above without separately using various calibration sensors. can do. Also, it is possible to easily cope with the case where the driving characteristics are different between the left and right wheels.

(2nd Embodiment)
Next, a second embodiment will be described. The description of the same items as those of the first embodiment (the items described with reference to FIGS. 1 and 2) will be omitted as appropriate.

  In the second embodiment, the EPB-ECU 9 drives the EPB 2 in a state where the predetermined hydraulic pressure is generated, moves the propulsion shaft 18 from the specified position to the brake disk 12 side, and contacts the piston 19. The stroke amount of the propulsion shaft 18 (or the number of motor revolutions corresponding to the stroke amount) is detected as a drive characteristic value (characteristic information is corrected).

  Hereinafter, the correction of the characteristic information will be described in detail with reference to FIGS. FIG. 6 is a graph showing how the W / C pressure and the like change over time when the characteristic information is corrected in the second embodiment. In the graph of FIG. 6A, the vertical axis represents the W / C pressure (MPa), and the horizontal axis represents time (ms). In the graph of FIG. 6B, the vertical axis represents the current detection value (A) of the motor 10, and the horizontal axis represents time (ms). In the graph of FIG. 6C, the vertical axis represents the stroke amount (mm) of the piston 19, and the horizontal axis represents time (ms). In the graph of FIG. 6D, the vertical axis represents the stroke amount (mm) of the propulsion shaft 18, and the horizontal axis represents time (ms).

  FIG. 7 is a graph showing characteristic information according to the second embodiment. In the graph of FIG. 7, the vertical axis represents the stroke amount (mm) of the propulsion shaft 18, and the horizontal axis represents the W / C pressure (MPa). FIG. 8 is a flowchart illustrating a process performed by the braking control device according to the second embodiment. The following processing is started, for example, in response to an operation of the operation SW 23 by the user when the vehicle stops.

  First, the ESC-ECU 8 generates a predetermined hydraulic pressure by controlling the service brake 1 (step S11 in FIG. 8). At this time, the W / C pressure (FIG. 6A) starts increasing at time t21 and reaches a predetermined hydraulic pressure (P) at time t22. In addition, the stroke amount of the piston 19 (FIG. 6C) increases from time t21 to time t22.

  Next, the EPB-ECU 9 drives the EPB 2 in a state where the predetermined hydraulic pressure is generated, moves the propulsion shaft 18 from the specified position to the brake disk 12 side, and contacts the piston 19 (step S12 in FIG. 8). ). At this time, at time t23 when the driving of the motor 10 is started, the current value (FIG. 6B) sharply increases due to the rush current, and after the current value stabilizes, the propulsion shaft 18 comes into contact with the piston 19. (That is, the clearance C1 in FIG. 2 becomes zero), the current value increases from time t24 to time t25. At this time, the stroke amount of the propulsion shaft 18 (FIG. 6D) increases from time t23 to time t24. If the propulsion shaft 18 is not at the specified position first, the propulsion shaft 18 may be moved to the specified position, and then moved to the brake disk 12 side.

  Next, the EPB-ECU 9 calculates the stroke amount of the propulsion shaft 18 based on the rotation speed of the motor 10 (Step S13 in FIG. 8).

  Next, the EPB-ECU 9 corrects the characteristic information (FIG. 7) based on the predetermined hydraulic pressure (P) and the stroke amount of the propulsion shaft 18 calculated in step S13.

  Next, the hydraulic pressure is reduced to zero by controlling the service brake 1 by the ESC-ECU 8. At this time, the W / C pressure (FIG. 6A) starts decreasing at time t26 and becomes zero at time t27.

  Next, the EPB-ECU 9 executes control to drive the EPB 2 to move the propulsion shaft 18 to the side facing the brake disk 12. At this time, the current value (FIG. 6B) sharply increases due to the rush current at the time t28 when the driving of the motor 10 is started, and thereafter, the influence of the rush current disappears at the time t29. The stroke amount of the piston 19 (FIG. 6C) and the stroke amount of the propulsion shaft 18 (FIG. 6D) decrease from time t29 to time t30.

  As described above, according to the second embodiment, the EPB-ECU 9 corrects the characteristic information based on the current driving characteristics in consideration of individual differences of components of the brake, aging, environmental temperature, and the like, thereby increasing the performance. An electric braking force with control accuracy can be realized.

  A plurality of stepwise hydraulic pressures are set as the predetermined hydraulic pressure (P in FIG. 6A), and the EPB-ECU 9 sets the drive characteristic value of the EPB 2 for each of the plurality of hydraulic pressures (for the propulsion shaft 18). If the characteristic information is corrected based on the stroke amount), the control accuracy can be further improved.

  As described above, the embodiment of the present invention has been exemplified, but the above embodiment is merely an example, and is not intended to limit the scope of the invention. The above embodiment can be implemented in other various forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. Also, the specifications (structure, type, number, etc.) of each configuration, shape, and the like can be appropriately changed and implemented.

  For example, in the above embodiment, the case of the disc brake type EPB has been described as an example, but the present invention can be applied to a drum brake type EPB.

  Further, the shape of the graph representing the characteristic information in the first embodiment is not limited to the linear shape illustrated in FIG. 4, and may be another shape. Further, the shape of the graph representing the characteristic information in the second embodiment is not limited to the curved shape illustrated in FIG. 7, and may be another shape.

  Further, while correcting the characteristic information based on the detected value, comparing the stored value with a map, a table, a mathematical expression, and the like, and detecting the detected value, when there is a predetermined difference or more between the stored value and the detected value, You may determine that it is abnormal.

  DESCRIPTION OF SYMBOLS 1 ... Service brake, 2 ... EPB, 5 ... M / C, 6 ... W / C, 7 ... Actuator, 8 ... ESC-ECU, 9 ... EPB-ECU, 10 ... Motor, 11 ... Brake pad (braking member), Reference numeral 12: brake disc (member to be braked), 13: caliper, 14: body, 14a: hollow portion, 14b: passage, 17: rotating shaft, 17a: male screw groove, 18: propulsion shaft, 18a: female screw groove, 19 ... piston, 23 ... operation SW, 24 ... display lamp, 25 ... front and rear G sensor, 26 ... M / C pressure sensor, 28 ... temperature sensor, 29 ... wheel speed sensor.

Claims (4)

A hydraulic brake device that generates a hydraulic braking force by pressing a braking member by hydraulic pressure toward a member to be braked that rotates integrally with a wheel;
An electric brake device that presses the braking member by driving a motor toward the member to be braked, and generates an electric braking force.
A hydraulic brake control unit that controls the hydraulic brake device,
An electric brake control unit that controls the electric brake device based on a drive characteristic value that is a detected value related to a drive characteristic of the electric brake device,
The hydraulic brake control unit generates a predetermined hydraulic pressure by controlling the hydraulic brake device,
The brake control device, wherein the electric brake control unit drives the electric brake device in a state where the predetermined hydraulic pressure is generated, and detects the drive characteristic value of the electric brake device with respect to the predetermined hydraulic pressure.   The electric brake control unit drives the electric brake device in a state where the predetermined hydraulic pressure is generated to move a propulsion shaft toward the member to be braked to contact a piston, and thereafter, the hydraulic brake After the hydraulic pressure is reduced to zero by the control of the hydraulic brake device by the control unit, the current value of the motor when the control for moving the propulsion shaft to the side facing the member to be braked is executed is controlled. The braking control device according to claim 1, wherein the braking control device detects the characteristic value as a characteristic value.   The electric brake control unit is configured to drive the electric brake device in a state where the predetermined hydraulic pressure is generated to move a propulsion shaft from a specified position to the braked member side and to contact the piston. The braking control device according to claim 1, wherein a stroke amount of a propulsion shaft is detected as the drive characteristic value. The hydraulic brake control unit generates a plurality of stepwise hydraulic pressures as the predetermined hydraulic pressure,
4. The brake control device according to claim 1, wherein the electric brake control unit detects the drive characteristic value of the electric brake device for each of the plurality of hydraulic pressures. 5.

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