JP5705050B2 - Electric brake device for vehicle - Google Patents

Description

  The present invention relates to an electric brake device for a vehicle.

  As a type of an electric brake device for a vehicle, one shown in Patent Document 1 is known. As shown in FIG. 1 of Patent Document 1, an electric brake device for a vehicle includes a braking member that generates a braking torque by being pressed against a braked member that rotates integrally with a wheel, Based on the electric motor 11 that is rotated in a predetermined direction by the supplied current and presses the braking member against the member to be braked, state quantity detection means that detects the state quantity of the vehicle, and the detected state quantity of the vehicle Current supply means for starting supply of current to the electric motor when it is determined that the required amount of change in braking torque is greater than a predetermined amount.

  According to this, only when the required amount of braking torque change based on the state quantity of the vehicle, that is, the difference between the detected actual pressure P and the determined target pressure P * is greater than a predetermined amount, Supply of current to the motor is started, and the electric motor is rotated. Thus, by reducing the operating frequency of the electric motor, the service life of the electric motor (particularly, a motor with a brush) is being extended.

JP-A-2005-247306

  However, only by reducing the operating frequency of the electric motor, the wear of the brush cannot be sufficiently suppressed, and as a result, the life of the electric motor cannot be sufficiently extended.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to extend the life of an electric motor in an electric brake device for a vehicle.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 1 is that in an electric brake device for a vehicle that generates a braking force by pressing a braking member against a member to be braked by an electric motor, an accelerator operation is performed. Accelerator reduction speed detection means for detecting the acceleration reduction speed, which is the speed when the member is moving toward the operation amount reduction side, and the smaller the accelerator reduction speed detected by the accelerator reduction speed detection means, the smaller the electric current in the electric motor. And motor control means for reducing the gap between the braking member and the braked member until the first gap reaches a predetermined value before the brake operating member is operated.

  According to a second aspect of the present invention, there is provided a structural feature of the first aspect, further comprising: an accelerator operation amount increase detection unit that detects that the accelerator operation member is moved to the operation amount increase side. When it is detected by the operation amount increase detection means that the accelerator operation member is operated to the operation amount increase side, a current is supplied to the electric motor to increase the gap between the braking member and the braked member. is there.

  The structural feature of the invention according to claim 3 is that the accelerator increasing speed detection for detecting the accelerator increasing speed, which is the speed when the accelerator operating member is moving to the operation amount increasing side in claim 1 or claim 2. The motor control means is configured to increase a gap between the braking member and the braked member by supplying a smaller current to the electric motor as the accelerator increase speed detected by the accelerator increase speed detecting means is smaller. .

  According to a fourth aspect of the present invention, there is provided a structural feature of the invention according to the second or third aspect, further comprising gap acquisition means for acquiring a gap between the braking member and the braked member, and the motor control means is acquired by the gap acquisition means. When the gap is less than or equal to the second gap predetermined value that is larger than the first gap predetermined value, the electric motor is energized to increase the gap between the braking member and the braked member.

  The structural feature of the invention according to claim 5 is characterized in that in any one of claims 1 to 4, there is provided time measuring means for measuring an elapsed time after the operation amount of the accelerator operation member becomes 0, The motor control means supplies an electric current to the electric motor when the elapsed time counted by the timing means exceeds a predetermined time without operating the brake operation member after the operation amount of the accelerator operation member becomes zero. Thus, the gap between the braking member and the braked member is increased.

  According to a sixth aspect of the present invention, there is provided a structural feature of any one of the first to fifth aspects, further comprising vehicle state detecting means for detecting a vehicle state, wherein the motor control means is detected by the vehicle state detecting means. When the vehicle state being used is a predetermined state, a current is supplied to the electric motor to change the gap between the braking member and the braked member.

  The structural feature of the invention according to claim 7 is that in any one of claims 1 to 6, when the operation amount of the accelerator operation member becomes 0 and then the brake operation member is operated, Brake operation start speed calculation means for calculating a brake operation start speed that is the initial operation speed of the operation is provided, and the motor control means increases the electric motor as the brake operation start speed calculated by the brake operation start speed calculation means decreases. A small current is applied to the first gap to make the gap between the braking member and the braked member smaller than a predetermined value of the first gap.

  The structural feature of the invention according to claim 8 is that in the electric brake device for a vehicle in which the braking member is pressed against the member to be braked by the electric motor to generate the braking force, the brake operation member moves to the operation amount decreasing side. The brake reduction speed detection means for detecting the brake reduction speed, which is the speed at the time of braking, and the smaller the brake reduction speed detected by the brake reduction speed detection means, the less the operation amount of the brake operation member becomes zero, Motor control means for energizing a small current to increase the gap between the braking member and the braked member.

  A structural feature of the invention according to claim 9 is that, according to claim 8, further comprising vehicle state detection means for detecting a vehicle state when the brake operation member is moving to the operation amount decreasing side, and the motor control means includes: When the vehicle state detected by the vehicle state detection means is a predetermined state, a current is supplied to the electric motor to increase the gap between the braking member and the braked member.

  In the invention according to claim 1 configured as described above, the amount of wear of the brush of the electric motor is proportional to the square of the magnitude of the current flowing through the electric motor, and the starting current is large among the current flowing through the electric motor. Focusing on the extremely large length, the gap between the braking member and the member to be braked is reduced until the first gap reaches a predetermined value before the brake operation member is operated. Thus, the magnitude of the starting current of the electric motor when the brake operating member is operated is reduced by reducing the gap between the braking member and the braked member before the brake operating member is operated. Can do.

Here, the smaller the accelerator decrease speed, the longer the time until the operation amount of the accelerator operation member becomes zero, and the longer the time until the brake operation member is operated after the operation amount of the accelerator operation member becomes zero. It is considered to be. Therefore, in the invention according to claim 1, the smaller the accelerator reduction speed, the smaller the current between the electric motor and the gap between the braking member and the member to be braked is reduced to a predetermined value. Thereby, the magnitude | size of the starting current of an electric motor when making the said clearance gap small before the brake operation member is operated as mentioned above can be made small.
As described above, by reducing the magnitude of the starting current of the electric motor, wear of the brush of the electric motor can be suppressed, and the life of the electric motor can be extended.

  Here, when the accelerator operation member is moved to the operation amount increase side, the operation amount of the accelerator operation member is increased and the probability that the brake operation member is operated is reduced. Accordingly, in the invention described in claim 2, with the above-described configuration, when it is detected that the accelerator operating member is operated to the operation amount increasing side, a current is supplied to the electric motor to thereby apply the braking member and the braked member. The gap between is increased. Thereby, drag can be reduced while suppressing wear of the brush of the electric motor (coexistence of suppression of wear of the electric motor and reduction of drag) can be achieved.

  In addition, the smaller the accelerator increase speed, the higher the probability that the accelerator operation member will move again to the operation amount decrease side. Therefore, in the invention described in claim 3, the smaller the accelerator increase speed, the smaller the electric current is supplied to the electric motor so as to increase the gap between the braking member and the braked member. As a result, when there is a high probability that the accelerator operating member will again move to the operation amount decreasing side, the magnitude of the starting current when the gap between the braking member and the braked member is increased is reduced, so the braking member and the braked member Wear of the brush of the electric motor accompanying enlarging the gap with the member can be suppressed.

  In the invention according to claim 4, with the above-described configuration, when the gap between the braking member and the braked member is equal to or less than the second gap predetermined value, that is, when there is a high probability that dragging will occur, an electric current is supplied to the electric motor. Energization is performed to increase the gap between the braking member and the braked member. As a result, it is possible to more suitably achieve both suppression of brushing of the electric motor and reduction of drag.

  Further, when a predetermined time elapses without the brake operation member being operated after the operation amount of the accelerator operation member becomes zero, the probability that the brake operation member will be operated thereafter is low. Therefore, in the invention according to claim 5, with the above-described configuration, when a predetermined time elapses without the brake operation member being operated after the operation amount of the accelerator operation member becomes 0, the electric motor is energized. Thus, the gap between the braking member and the braked member is increased. As a result, it is possible to more suitably achieve both suppression of wear of the brush of the electric motor and reduction of drag.

  Moreover, it may be preferable not to change the clearance between the braking member and the braked member depending on the vehicle state. Therefore, according to the sixth aspect of the present invention, when the vehicle state is a predetermined state, the electric motor is energized to change the gap between the braking member and the member to be braked. Thereby, the abrasion of the brush of the electric motor can be suppressed without affecting the braking performance of the vehicle.

  According to the seventh aspect of the present invention, when the brake operation member is operated after the operation amount of the accelerator operation member becomes 0, the electric motor has a smaller current as the brake operation start speed is lower. The gap between the braking member and the braked member is made smaller than the first gap predetermined value. Thus, the magnitude of the starting current of the electric motor accompanying the start of operation of the brake operating member can be further reduced in accordance with the operation of the brake operating member, and the amount of wear on the brush of the electric motor can be further suppressed. it can.

  By the way, the smaller the brake decreasing speed, the lower the probability that the accelerator operating member is immediately operated after the operation amount of the brake operating member becomes zero. Accordingly, in the invention described in claim 8, with the above-described configuration, the smaller the brake reduction speed is, the smaller the operation amount of the brake operation member becomes, and the smaller the electric current is supplied to the electric motor after the operation amount of the brake operation member becomes 0. The gap is made larger. Thereby, since the magnitude | size of the starting current of an electric motor when enlarging the said clearance gap becomes small, abrasion of the brush of an electric motor can be suppressed.

  Here, depending on the vehicle state, it may be preferable not to change the gap between the braking member and the braked member. Therefore, according to the ninth aspect of the present invention, when the vehicle state is a predetermined state, the electric motor is energized to change the gap between the braking member and the member to be braked. Thereby, the abrasion of the brush of the electric motor when the gap between the braking member and the member to be braked is increased can be suppressed without affecting the braking performance of the vehicle.

It is a schematic diagram showing the composition of one embodiment of the electric brake equipment by the present invention. It is an example of the flowchart of the control program (When filling the clearance gap between a pad and a rotor when returning an accelerator pedal) performed by brake ECU shown in FIG. It is an example of the flowchart of the control program (when depressing a brake pedal after returning an accelerator pedal) performed by brake ECU shown in FIG. It is an example of the flowchart of the control program (when depressing an accelerator pedal after returning a brake pedal) performed by brake ECU shown in FIG. It is an example of the flowchart of the control program (when expanding a clearance gap after returning a brake pedal) performed by brake ECU shown in FIG. It is a map which shows the correlation with an accelerator decreasing speed and a motor current. It is a figure which shows each time change of an accelerator opening degree, an accelerator decreasing speed, a motor current, and a gap filling rate in order from the top. It is a figure which shows each time change of a request | requirement braking force, a braking raise speed, a motor starting current, and a piston stroke in order from the top. It is a time chart of the Example at the time of applying this invention, and has shown the accelerator amount, the brake amount, the clearance gap S, and the starting current in an order from the top. It is a time chart of an Example when not applying the present invention, and shows accelerator amount, brake amount, clearance S, and starting current in order from the top. It is a map which shows the correlation of an accelerator increase speed and a motor current. It is a figure which shows each time change of an accelerator opening degree, an accelerator increase speed, a motor current, and a gap filling rate in order from the top. It is a map which shows correlation with a brake decreasing speed and a motor current.

  Hereinafter, an embodiment in which an electric brake device for a vehicle according to the present invention (hereinafter simply referred to as an electric brake device) is applied to a vehicle will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an electric brake device.

  The electric brake device is for braking a vehicle by a braking force generated by a driving force of an electric motor. As shown in FIG. 1, a brake pedal 11 that is a brake operation member and an accelerator that is an accelerator operation member. The pedal 12 includes left and right front and rear wheels W (only one of them (the front left wheel Wfl is shown in FIG. 1)), and a brake ECU 30 that is a control device. Yes.

  A brake stroke sensor 11 a is attached to the brake pedal 11. The brake stroke sensor 11a detects the stroke of the brake pedal 11, that is, the depression amount, and the detection result is transmitted to the brake ECU 30.

  The accelerator pedal 12 is provided with an accelerator opening sensor 12a. The accelerator opening sensor 12a detects the opening of the accelerator pedal 12, that is, the amount of depression, and the detection result is transmitted to the brake ECU 30.

  The electric disc brake 20 includes a disc rotor (sometimes abbreviated as a rotor) 21, a pair of brake pads (sometimes abbreviated as pads) 22 a and 22 b, a mounting bracket 23, a caliper 24, and a piston (pressure member) 25. An electric motor 26, a ball screw 27, a position sensor 28, and a pressure sensor 29.

  The disk rotor 21 is a member to be braked that rotates about the rotation axis C integrally with the wheel W. Both surfaces of the disk rotor 21 are friction surfaces (not shown), and a pair of brake pads 22a and 22b are disposed to face the friction surfaces.

  The pair of brake pads 22a and 22b are braking members that generate a braking force by pressing the disk rotor 21 from both sides. Each brake pad 22a, 22b is provided with a friction material (not shown) in contact with each friction surface of the disk rotor 21 on the front surface, and a steel back plate (not shown) is fixed to the back surface of each friction material. It has a structure.

  The mounting bracket 23 is non-rotatably attached to a vehicle body side member (for example, a suspension such as a knuckle, not shown) in a state of straddling the pair of brake pads 22a and 22b. The mounting bracket 23 holds the pair of brake pads 22a and 22b so as to be movable in a direction parallel to the rotation axis C of the disk rotor 21 (pad moving direction).

  The caliper 24 is held by the mounting bracket 23 so as to be relatively movable along the pad moving direction. In the present embodiment, the caliper 24 is configured, for example, as a so-called floating caliper type. The caliper 24 is integrally provided with an arm (not shown), and a pair of pins 24a (only one shown) extending from the arm in parallel to the pad moving direction are slidably fitted into the pin holes 23a of the mounting bracket 23. Has been. The caliper 24 is not limited to the floating caliper type, and may be configured as a floating yoke type or an opposed piston type.

  A piston 25 is disposed behind the inner pad 22a of the pair of brake pads 22a and 22b so as to be movable in the axial direction. When the piston 25 moves in the direction of the inner pad 22a by a predetermined amount, the piston 25 is brought into contact with the back surface of the inner pad 22a on the front surface thereof. An electric motor 26 is disposed behind the piston 25. The piston 25 and the electric motor 26 are arranged coaxially with each other in parallel to the pad moving direction, and are connected to each other by a ball screw 27 as a motion conversion mechanism.

  A housing (not shown) of the electric motor 26 is fixed to the caliper 24. The stator (not shown) of the electric motor 26 is fixed to the inside of the housing, and includes a metal core and a coil wound around the core. In addition, a permanent magnet is provided in a state facing the inner side of the stator with a slight distance. The permanent magnet is fixed to a nut (not shown) of the ball screw 27 and constitutes a rotor (not shown) of the electric motor 26 together with the nut.

  With such a configuration, when the electric motor 26 is rotated forward (rotated in a predetermined direction), the piston 25 is moved rightward in FIG. 1 by the action of the ball screw 27, and the piston 25 is an inner pad as a braking member. While pushing 22a toward the disk rotor 21 which is a member to be braked, the disk rotor 21 is pressed. At this time, since the disc rotor 21 cannot move in the axial direction, when the piston 25 presses the disc rotor 21, the caliper 24 slides leftward along the pad moving direction by the reaction force. Therefore, the outer pad 22b, which is a braking member, is pushed toward the disk rotor 21, which is a member to be braked, and the disk rotor 21 is pressed.

  Conversely, when the electric motor 26 is reversely rotated (rotated in the direction opposite to the predetermined direction), the piston 25 is moved leftward in FIG. 1, and the piston 25 is moved in a direction away from the disk rotor 21. To do. At this time, the caliper 24 slides in the right direction. Therefore, the outer pad 22b is moved away from the disk rotor 21.

  The position sensor 28 detects the rotation (rotation position, rotation angle) of the rotor of the electric motor 26 and transmits the detection result to the brake ECU 30. By detecting the rotation (rotation position, rotation angle) of the rotor of the electric motor 26, the relative position of the inner pad 22a with respect to the motor 11 can be detected. The position sensor 28 is configured by a combination of a permanent magnet and a Hall element. The position sensor 28 may be configured by a resolver.

  A pressure sensor 29, which is a strain sensor, is embedded in the surface of the piston 25 that contacts the inner pad 22a. The pressure sensor 29 is configured to detect an actual pressing force with which the piston 25 presses the inner pad 22a from a distortion amount generated in the piston 25. This detection result is transmitted to the brake ECU 30.

  The brake ECU 30 is configured by a microcomputer, and controls and drives the electric motor 26 according to a control program stored in advance. That is, in normal brake control, the brake ECU 30 calculates a required braking force (target braking force) corresponding to the stroke detected by the brake stroke sensor 11 a and detects the calculated target braking force and the pressure sensor 29. The drive current is determined by feedback control from the actual applied pressure, and the electric motor 26 is driven by this drive current.

  The brake ECU 30 is provided with each wheel W to detect the wheel speed of each wheel and detects the rotation of the output shaft of the transmission (not shown), thereby detecting the vehicle speed (hereinafter referred to as the vehicle speed). ) For detecting the vehicle speed, the gradient sensor 43 for detecting the vehicle gradient, and the motor current sensor 44 for detecting the current value of the current supplied to the electric motor 26 are detected. The result is entered.

  Next, the operation of the electric brake device configured as described above will be described with reference to the flowcharts shown in FIGS.

1) When the gap between the pad and the rotor is filled when the accelerator pedal is returned When the ignition switch (not shown) is turned on, the brake ECU 30 repeats the control program for the electric brake device shown in FIG. 2 every predetermined short time. Run. In step 102, the brake ECU 30 determines whether or not the accelerator-off gap filling mode is set. The accelerator-off gap filling mode is a control for filling a gap S (hereinafter simply referred to as a gap S) between the brake pads 22a and 22b and the disc rotor 21 when the accelerator pedal 12 is returned (gap filling control). Refers to the mode in which The brake ECU 30 determines that the accelerator-off gap filling mode is set if the "accelerator-off gap filling mode" is set, and if the accelerator-off gap filling mode is not set, the brake ECU 30 sets the accelerator-off gap gap. It is determined that the mode is not fill mode. Immediately after the ignition switch is turned on, the brake ECU 30 determines that it is not in the accelerator-off gap filling mode because it is not set to the “accelerator-off gap filling mode”.

  In step 104, the brake ECU 30 determines whether or not the accelerator amount that is the amount of depression of the accelerator pedal 12 is decreased. The brake ECU 30 acquires the detection result from the accelerator opening sensor 12a, and determines whether or not the accelerator amount is decreased based on the difference between the accelerator opening acquired this time and the accelerator opening acquired and stored last time. judge. If the currently acquired accelerator opening is smaller than the previously acquired and stored accelerator opening, the brake ECU 30 determines that the accelerator amount is decreasing and advances the program to step 106. If the accelerator opening acquired this time is the same or larger than the accelerator opening acquired and stored last time, the brake ECU 30 determines that the accelerator amount is constant or increased, and temporarily terminates the program.

  When the reduction of the accelerator amount is started, the brake ECU 30 sets the accelerator-off gap filling mode (step 106). This is because it is determined “YES” at step 102 from the next time and the program is jumped to the processing at step 114. Then, in step 108, the brake ECU 30 detects an accelerator decrease speed that is a speed when the accelerator pedal 12 is moved (returned) to the operation amount decreasing side (accelerator decrease speed detecting means). Specifically, the brake ECU 30 calculates the accelerator reduction speed based on the difference between the accelerator opening acquired this time and the accelerator opening acquired and stored last time, as in step 104. Further, a plurality of accelerator openings that have been acquired and stored before this time may be averaged, and the accelerator reduction speed may be calculated from the average value.

  In step 110, the brake ECU 30 calculates a motor current (target motor current value) that is a current value for energizing the electric motor 26. The brake ECU 30 calculates a motor current corresponding to the accelerator reduction speed detected at step 108 from the map (see FIG. 6) showing the relationship between the accelerator reduction speed and the motor current and the accelerator reduction speed detected previously. calculate.

  As shown in FIG. 6, the map showing the relationship between the accelerator reduction speed and the motor current is set such that the motor current decreases as the accelerator reduction speed decreases. This is due to the following reason. It is considered that the time it takes from the time when the operation amount of the accelerator pedal 12 becomes 0 to the time when the operation of the brake pedal 11 is started thereafter becomes longer as the accelerator decrease speed is smaller. Moreover, in order to suppress the electric current which flows into the electric motor 26 small, the gap filling should be completed from the time when the operation amount of the accelerator pedal 12 becomes 0 to the time when the operation of the brake pedal 11 is started thereafter. is necessary. Therefore, when the accelerator decreasing speed is small, the gap S can be filled over a relatively long time. On the other hand, when the accelerator decreasing speed is large, the gap S must be filled in a relatively short time. Because.

  Furthermore, the case where the motor current value at the time of gap filling is set from the accelerator operation will be described with reference to FIG. FIG. 7 shows changes with time in the accelerator opening, the accelerator decrease speed, the motor current, and the gap filling rate in order from the top. In FIG. 7, the decreasing speed of the accelerator pedal 12 decreases in the order of the solid line, the broken line, and the two-dot broken line.

  The accelerator opening is detected by the accelerator opening sensor 12a. The accelerator decrease speed is calculated from the accelerator opening, and decreases as the time required for the accelerator opening to become zero is longer. The motor current is calculated from the map shown in FIG. 6 and the calculated accelerator decrease speed. The calculated motor current is applied to the electric motor 26. Thereby, the smaller the accelerator decrease speed, the smaller the motor current value can fill the gap S, and the longer it takes to fill the gap S.

  In step 112, the brake ECU 30 energizes the motor current calculated in step 110 to drive the electric motor 26. At this time, for example, the brake ECU 30 performs PWM control with a duty ratio corresponding to the motor current. That is, when the accelerator return is started, the brake ECU 30 starts gap filling control by the electric motor 26 at the same time.

  The brake ECU 30 switches the first gap predetermined value to the first specified value or the second specified value according to the vehicle state. First, the brake ECU 30 detects the vehicle state in step 114 (vehicle state detection means). The vehicle state refers to, for example, a traveling state of the vehicle, and includes a low vehicle speed state, a high vehicle speed state, a downhill traveling state, an uphill traveling state, and the like. The low vehicle speed state and the high vehicle speed state can be detected by comparing the vehicle speed detected by the vehicle speed sensor 42 with a vehicle speed threshold value. The downhill traveling state and the uphill traveling state can be detected based on the gradient detected by the gradient sensor 43.

  Next, the brake ECU 30 changes the gap (first gap predetermined value) by supplying current to the electric motor 26 when the vehicle state detected by the vehicle state detecting means is a predetermined state in steps 116 to 120. To do. In step 116, the brake ECU 30 determines whether or not the vehicle state detected in step 114 is a predetermined state. In the present embodiment, the predetermined states are a low vehicle speed state and a downhill traveling state.

  If it is determined that the vehicle state is not the predetermined state, the brake ECU 30 determines “NO” in step 116 and sets the first gap predetermined value to the first specified value (step 118). If the brake ECU 30 determines that the vehicle state is the predetermined state, the brake ECU 30 determines “NO” in step 116 and sets the first gap predetermined value to the second specified value (step 120).

  The first clearance predetermined value indicates a predetermined value (target value) of the clearance S when the clearance S is filled when the accelerator pedal 12 is returned. The first specified value is a normal gap predetermined value that is set to a value that causes a slight gap immediately before the pads 22a and 22b contact the rotor 21. The second specified value is set to a value larger than the first specified value. The second specified value is determined by the pads 22a and 22b and the rotor when the driver makes a creep drive with the accelerator off in a low vehicle speed state when there is a traffic jam, and when the driver makes an inertia run with the accelerator off during downhill driving. 21 is set to a value that does not cause dragging.

  Therefore, when filling the gap S when the accelerator pedal 12 is returned, the target value of the gap is a relatively small gap in consideration of the next operation of the brake pedal 11 when the vehicle state is not a predetermined state. On the other hand, when the vehicle state is a predetermined state, the first clearance is larger than the normal clearance predetermined value from the viewpoint of preventing drag between the pads 22a and 22b and the rotor 21. 2 Set to the default value. Thereby, when the vehicle state detected by the vehicle state detection means is a predetermined state, the electric motor 26 can be energized to change the gap (first gap predetermined value).

  The brake ECU 30 acquires the clearance S in step 122. The gap S may be estimated from the axial movement distance of the rotor calculated from the rotation (rotation position, rotation angle) of the rotor of the electric motor 26 detected by the position sensor 28 and the initial position of the rotor. Instead of estimation, a configuration may be adopted in which a gap sensor that detects the gap S between the pads 22a and 22b and the rotor 21 is provided for detection. When the electric motor 26 is being driven and the gap S reaches the first gap predetermined value, the brake ECU 30 determines “YES” in step 124 and stops the gap filling control. Specifically, the brake ECU 30 determines in step 124 whether or not the gap S is greater than or equal to a first gap predetermined value.

  If the gap S is less than the first gap predetermined value, the brake ECU 30 determines “NO” in step 124 and temporarily terminates the program. If the gap S is greater than or equal to the first gap predetermined value, the brake ECU 30 determines “YES” in step 124, stops driving the electric motor 26 (step 126), and sets the accelerator-off gap filling mode. Release (step 128).

2) When the brake pedal is depressed after the accelerator pedal is returned When the ignition switch (not shown) is turned on, the brake ECU 30 repeatedly executes the control program for the electric brake device shown in FIG. 3 every predetermined short time. In step 202, the brake ECU 30 determines whether or not the motor is being driven. Motor driving refers to driving of the electric motor 26 in steps 218 to 222 and 224 described later. The brake ECU 30 determines “YES” if the motor is being driven (if the motor driving flag is 1), and “NO” if the motor is not being driven (if the motor driving flag is 0). To do. The motor driving flag is a flag indicating that the electric motor 26 is being driven by steps 218 to 222 and 224 described later. Immediately after the ignition switch is turned on, the brake ECU 30 determines that “NO” in step 202 because the motor is not being driven.

  In step 204, the brake ECU 30 determines whether it is timed. Timekeeping refers to measuring the elapsed time after the time when the accelerator pedal 12 is completely turned off (the time when the accelerator amount becomes 0). The brake ECU 30 determines “YES” if the time is being measured (if the time-measurement flag is 1), and “NO” if it is not being measured (if the time-measurement flag is 0). The timekeeping flag is a flag indicating that the elapsed time after the time when the accelerator amount becomes zero is being timed. Immediately after the ignition switch is turned on, the brake ECU 30 determines that “NO” in step 204 because it is not timed.

  In step 206, the brake ECU 30 determines whether or not the accelerator-off gap filling mode is in the same manner as in step 102 described above. If the accelerator-off gap filling mode is selected, “YES” is determined. If the accelerator-off gap filling mode is not set, “NO” is determined. Immediately after the ignition switch is turned on, the brake ECU 30 determines that it is not in the accelerator-off gap filling mode because it is not set to the “accelerator-off gap filling mode”.

  If the motor is not driven, is not timed, and is set to the accelerator-off gap filling mode, the brake ECU 30 determines “NO”, “NO”, “YES” in steps 202, 204, 206. Then, the program proceeds to step 208.

  In step 208, the brake ECU 30 determines whether or not the accelerator amount that is the amount of depression of the accelerator pedal 12 has become zero. That is, the brake ECU 30 determines whether or not the accelerator pedal 12 has completely returned to the position before the depression (initial position) when the gap S is filled when the accelerator pedal 12 is returned. The brake ECU 30 acquires the detection result from the accelerator opening sensor 12a, and determines that the accelerator amount has become zero if the accelerator opening that is the detection result is zero.

  In step 210, the brake ECU 30 starts measuring the elapsed time from when the accelerator amount becomes zero. That is, the elapsed time after the operation amount of the accelerator pedal 12 becomes zero is measured (time measuring means). Further, the brake ECU 30 sets a timekeeping flag to 1 in step 212. If the accelerator opening is larger than 0, the brake ECU 30 determines that the accelerator amount is not 0, and advances the program to step 214.

  In step 214, the brake ECU 30 determines whether or not the elapsed time from the time when the accelerator amount becomes 0 is shorter than the predetermined time (whether or not the elapsed time from when the accelerator amount becomes 0 has reached the predetermined time). ). The brake ECU 30 determines “YES” in step 214 and advances the program to step 216 until the elapsed time reaches a predetermined time. The predetermined time is set to a time during which it can be determined that the brake pedal 11 is not operated after the accelerator amount becomes zero.

  In step 216, the brake ECU 30 determines whether or not the brake pedal 11 has been depressed (whether or not depression has been started). The brake ECU 30 acquires the detection result from the brake stroke sensor 11a, and determines that the brake pedal 11 has been depressed when the result is a value greater than zero. If the acquired detection result is 0, the brake ECU 30 determines that the brake pedal 11 has not been depressed, and once ends the program.

  Then, when the depression of the brake pedal 11 is started before the elapsed time reaches the predetermined time, the brake ECU 30 determines “YES” in steps 214 and 216, and in steps 218 to 222, The electric motor 26 is driven according to the operation start speed. That is, the brake ECU 30 performs control to apply the braking force by driving the electric motor 26 according to the depression state of the brake pedal 11.

  The driving of the electric motor 26 according to the brake operation start speed will be described with reference to FIG. FIG. 8 shows each time change of the required braking force, the braking increase speed, the motor starting current, and the piston stroke in order from the top. In FIG. 8, the depression speed of the brake pedal 11 decreases in the order of the solid line, the broken line, and the two-dot broken line.

  The brake ECU 30 calculates the driver's required braking force from the brake stroke in the depressed state detected by the brake stroke sensor 11a. The brake stroke and the required braking force are in a directly proportional relationship. Furthermore, the brake ECU 30 calculates a braking increase speed (= brake operation start speed) that is a required braking force per unit time from the brake stroke or the driver's required braking force (step 218). The brake ECU 30 calculates a motor starting current (motor current) that decreases as the braking increase speed decreases (step 220). Then, the brake ECU 30 applies the calculated motor starting current to the electric motor 26 to drive the electric motor 26 (step 222).

  Thereby, the stroke speed of the piston 25 of the electric disk rotor 20 can be reduced as the braking increase speed is smaller, that is, as the depression speed of the brake pedal 11 is smaller. That is, the starting current of the electric motor 26 can be suppressed to be small by suppressing the rising speed at the beginning of the movement of the pad 22a or 22b that is stopped with a predetermined gap from the rotor 21. it can.

  On the other hand, when the elapsed time exceeds the predetermined time without the brake pedal 11 being depressed, the brake ECU 30 determines “NO” in step 214, and in step 224, sets the gap S as an appropriate gap. Then, the electric motor 26 is driven.

In step 224, the brake ECU 30 drives the electric motor 26 so as to widen the pad 22a or 22b that is stopped with a gap of a first gap predetermined value with respect to the rotor 21. When the gap S becomes an appropriate gap, the brake ECU 30 stops driving the electric motor 30. The appropriate gap is larger than the first gap predetermined value, for example, the gap when the pads 22a and 22b are in the initial position.
As a result, when the elapsed time measured by step 210 (time measuring means) becomes equal to or longer than the predetermined time without the brake pedal 11 being operated after the operation amount of the accelerator pedal 12 becomes zero, the electric motor 26 is The gap S between the pads 22a and 22b and the rotor 21 can be increased by supplying a current.

  After the processing of Steps 218 to 222 or Step 224 described above, the brake ECU 30 sets a motor driving flag indicating that the electric motor 26 is being driven to 1 (Step 226). Thereby, the brake ECU 30 can determine “YES” in the above-described step 202 after the next time, and can jump the program to step 228 via step 230.

  In step 230, the brake ECU 30 determines whether or not the current control of the electric motor 26 is control for filling the gap S. The brake ECU 30 determines that the control is to fill the gap S when the control in the above-described steps 218 to 222 is performed, and the control to fill the gap S when the control in the above-described step 224 is performed. It is determined that it is not (control to widen the gap S).

  If the control is not to fill the gap S, the brake ECU 30 determines “NO” in step 230 and advances the program to step 228. On the other hand, if the control is to fill the gap S, the brake ECU 30 determines “YES” in step 230 and advances the program to step 232.

  The brake ECU 30 determines “YES” in step 232 and determines the brake control in step 234 when the gap S becomes smaller than the first gap predetermined value while the electric motor 26 is driven by the processing in steps 218 to 222. Switch to. The brake control is a control in which the electric motor 26 is controlled to apply a braking force according to the depression amount of the brake pedal 11. On the other hand, if the gap S is greater than or equal to the first gap predetermined value, the brake ECU 30 determines “NO” in step 232 and advances the program to step 228.

  In step 228, the brake ECU 30 determines whether or not the driving of the electric motor 26 has been completed. Specifically, when the brake ECU 30 starts driving the electric motor 26 according to the brake operation start speed in steps 218 to 222, the electric motor 26 is set when the depression amount of the brake pedal 11 becomes zero. It is determined that the driving of is finished. In addition, when the brake ECU 30 starts driving the electric motor 26 so that the gap S is an appropriate gap in step 224, the driving of the electric motor 26 is terminated when the gap S becomes an appropriate gap. judge.

  If the drive of the electric motor 26 has not ended, the brake ECU 30 determines “NO” in step 228 and temporarily ends the program. When the driving of the electric motor 26 is finished, the brake ECU 30 determines “YES” in step 228, sets the time-measurement flag to 0 (step 236), and sets the motor-driving flag to 0 (step 236). Step 238).

  2 and 3 will be described with reference to FIGS. 9 and 10. FIG. FIG. 9 shows an embodiment when the present invention is applied, and FIG. 10 shows an embodiment when the present invention is not applied. 9 and 10 show the accelerator amount, the brake amount, the clearance S, and the starting current in order from the top.

  First, a case where the present invention is applied will be described. When the return of the accelerator pedal 12 that has been depressed so far is started at time t1, gap filling control by the electric motor 26 is started at the same time (steps 104 to 112). Thereafter, when the gap S reaches the first gap predetermined value, the gap filling control is stopped (time t3, steps 124 and 126). At this time, by driving the electric motor 26 with a smaller motor current value as the accelerator decrease speed is smaller, the gap S can be narrowed to the first gap predetermined value with the optimum (minimum) motor current value. Therefore, the starting current can be suppressed to a low level, and the reduction in wear of the brush of the electric motor 26 can be suppressed to a low level.

  When the depression of the brake pedal 11 is started at time t4 (steps 208 to 216) before the predetermined time has elapsed from the time when the accelerator amount becomes 0 (time t2), according to the depression start speed of the brake pedal 11. The electric motor 26 is driven (steps 218 to 222). At this time, as described above, the starting current of the electric motor 26 is suppressed by suppressing the rising speed at the beginning of the movement of the pad 22a or 22b that is stopped with a gap of the first gap predetermined value with respect to the rotor 21. Can be suppressed small.

  Thereafter, gap filling control is further performed, the gap S becomes 0 at time t5, and further pressurization by the piston 25 is started. Therefore, at time t5, a relatively large starting current flows because of resistance during pressurization.

  Thus, before the braking control is started, the starting current can be suppressed to a minimum by filling the gap S to the first gap predetermined value in advance. Furthermore, at the time of braking control, the starting current can be suppressed to a minimum by slowly raising the piston stroke of the electric disc brake 10.

  Next, a case where the present invention is not applied will be described. At time t11, the accelerator pedal 12 that has been depressed so far is started to return, and at time t12, the accelerator amount becomes zero. Thereafter, when the depression of the brake pedal 11 is started at time t13, the gap filling control by the electric motor 26 is started at the same time. At this time, since it is necessary to fill the relatively large gap S in a short time, the electric motor 26 must be operated with a large current, and the starting current is larger than that of the present invention. After that, the gap S becomes 0 at time t14, but the starting current at time t14 is the same as in the present invention.

  As is clear from the above, by applying the present invention, compared to the case where the present invention is not applied, the starting current at the time of starting to fill the gap can be suppressed to be small, and consequently the brush of the electric motor 26 Can reduce wear reduction.

3) When the accelerator pedal is stepped on after the brake pedal is returned When the ignition switch (not shown) is turned on, the brake ECU 30 repeatedly executes the control program for the electric brake device shown in FIG. 4 every predetermined short time. In step 302, the brake ECU 30 determines whether or not the accelerator-on-gap clearance mode is set. The accelerator-on-gap opening mode is a mode in which when the accelerator pedal 12 is depressed after the brake pedal 11 is returned, the control for opening (expanding) the gap S (gap opening control) is performed. The brake ECU 30 determines that the accelerator-on-gap opening mode is set if the “accelerator-on-gap opening mode” is set, and if the accelerator-on-gap opening mode is not set, the brake ECU 30 determines It is determined that the mode is not open. Immediately after the ignition switch is turned on, the brake ECU 30 determines that it is not in the accelerator opening gap opening mode because it is not set to the “accelerator opening gap opening mode”.

  In step 304, the brake ECU 30 determines whether or not the accelerator amount that is the amount of depression of the accelerator pedal 12 is increasing. That is, the brake ECU 30 detects that the accelerator pedal 12 is moved to the operation amount increase side (accelerator operation amount increase detection means). The brake ECU 30 acquires the detection result from the accelerator opening sensor 12a, and determines whether or not the accelerator amount is increased based on the difference between the accelerator opening acquired this time and the accelerator opening acquired and stored last time. judge. The brake ECU 30 determines that the accelerator amount is increasing when the accelerator opening acquired this time is larger than the accelerator opening acquired and stored last time, and advances the program to step 306. When the accelerator opening acquired this time is the same or smaller than the accelerator opening acquired and stored last time, the brake ECU 30 determines that the accelerator amount is constant or decreased and ends the program once.

  In step 306, the brake ECU 30 acquires the clearance S in the same manner as in step 122 described above (gap acquisition means). In step 308, the brake ECU 30 determines whether or not the gap S is smaller than a second gap predetermined value. The second gap predetermined value is set to a value larger than the first gap predetermined value described above, and is set to be a gap that does not cause drag between the pads 22a and 22b and the rotor 21. When the gap S is equal to or larger than the second gap predetermined value, the brake ECU 30 has already widened to such an extent that no drag is generated between the pads 22a and 22b and the rotor 21, so that the brake ECU 30 needs to be further widened. Therefore, the electric motor 26 is not driven.

  On the other hand, when the gap S is less than the second gap predetermined value, for example, when the gap S is relatively narrow immediately after the operation of the brake pedal 11 is finished, the brake ECU 30 sets the gap S to the pad 22a. , 22b and the rotor 21 may be dragged, so that the electric motor 26 is driven to widen the gap S.

  Specifically, when the increase in the accelerator amount is started and the gap S is smaller than the second gap predetermined value, the brake ECU 30 determines “YES” in steps 304 and 308, respectively, and opens the gap when the accelerator is on. The mode is set (step 310). This is because “YES” is determined in step 302 from the next time and the program is jumped to the processing in step 318. In step 312, the brake ECU 30 detects an accelerator increase speed that is a speed when the accelerator pedal 12 is moving (returned) to the operation amount increasing side (accelerator increasing speed detecting means). Specifically, the brake ECU 30 calculates the accelerator increase speed based on the difference between the accelerator opening acquired this time and the accelerator opening acquired and stored last time, as in step 304. Further, a plurality of accelerator openings that are acquired and stored before this time may be averaged, and the accelerator increase speed may be calculated from the average value.

  In step 314, the brake ECU 30 calculates a motor current (target motor current value) that is a current value for energizing the electric motor 26. The brake ECU 30 calculates a motor current corresponding to the accelerator increase speed detected at step 312 from the map (see FIG. 11) showing the relationship between the accelerator increase speed and the motor current and the accelerator increase speed detected previously. calculate.

  As shown in FIG. 11, the map showing the relationship between the accelerator increase speed and the motor current is set so that the motor current decreases as the accelerator increase speed decreases. This is due to the following reason. When the accelerator pedal 12 is moved to the operation amount increase side, the probability that the brake pedal 11 is operated decreases as the operation amount of the accelerator pedal 12 increases. Further, the smaller the accelerator increase speed, the higher the probability that the accelerator pedal 12 will again move toward the operation amount decreasing side. Therefore, when the accelerator increasing speed is small, the time until the brake pedal 11 is operated is shorter than when the accelerator increasing speed is large, and therefore it is preferable that the gap S is small.

  Furthermore, the case where the motor current value at the time of opening a gap is set with reference to the accelerator operation will be described with reference to FIG. FIG. 12 shows each time change of the accelerator opening, the accelerator increasing speed, the motor current, and the gap filling rate in order from the top. In FIG. 12, the increasing speed of the accelerator pedal 12 decreases in the order of a solid line, a broken line, and a two-dot broken line.

  The accelerator opening is detected by the accelerator opening sensor 12a. The accelerator increase speed is calculated from the accelerator opening, and decreases as the time required for the accelerator opening to reach the predetermined opening becomes longer. The motor current is calculated from the map shown in FIG. 11 and the calculated accelerator increase speed. The calculated motor current is applied to the electric motor 26. Thereby, the smaller the accelerator increase speed, the wider the gap S can be with a smaller motor current value, and the longer it takes to widen the gap S to a predetermined width.

  In step 316, the brake ECU 30 drives the electric motor 26 by energizing the motor current calculated in step 314 as in step 112 described above. When the accelerator depression is started, the brake ECU 30 starts gap opening control by the electric motor 26 at the same time.

  The brake ECU 30 acquires the clearance S in the same manner as in step 306 described above (step 318), and when the electric motor 26 is driven, if the clearance S reaches the second clearance predetermined value, “YES” is determined in step 320. Determine and stop gap opening control. Specifically, in step 320, the brake ECU 30 determines whether or not the gap S is equal to or greater than a second gap predetermined value.

  If the gap S is less than the second gap predetermined value, the brake ECU 30 determines “NO” in step 320 and temporarily terminates the program. If the clearance S is equal to or greater than the second clearance predetermined value, the brake ECU 30 determines “YES” in step 320, stops the driving of the electric motor 26 (step 322), and sets the accelerator-on clearance opening mode. Release (step 324).

4) When the gap is widened after the brake pedal is returned When the ignition switch (not shown) is turned on, the brake ECU 30 repeatedly executes the control program for the electric brake device shown in FIG. 5 every predetermined short time. In step 402, the brake ECU 30 determines whether or not the brake-off gap opening mode is set. The brake opening gap opening mode is a mode in which control (gap opening control) is performed to widen (open) the gap S after the brake pedal 11 is returned. The brake ECU 30 determines that the brake-off gap opening mode is set if the "brake-off gap opening mode" is set, and if the brake-off gap opening mode is not set, the brake ECU 30 sets the brake-off gap opening mode. It is determined that the mode is not open. Immediately after the ignition switch is turned on, the brake ECU 30 determines that it is not in the brake-off gap opening mode because it is not set to the “brake-off gap opening mode”.

  In step 404, the brake ECU 30 determines whether or not the brake amount, which is the depression amount of the brake pedal 11, has decreased. The brake ECU 30 acquires the detection result from the brake stroke sensor 11a, and determines whether or not the brake amount is reduced based on the difference between the brake stroke acquired this time and the brake stroke acquired and stored last time. If the brake stroke acquired this time is smaller than the brake stroke acquired and stored last time, the brake ECU 30 determines that the brake amount has decreased, and advances the program to step 408. The brake ECU 30 determines that the brake amount is constant or increased when the brake stroke acquired this time is the same or larger than the brake stroke acquired and stored last time, and controls the electric motor 26 to control the brake pedal 11. A braking force corresponding to the amount of depression is applied (step 406).

  In step 408, the brake ECU 30 detects a brake reduction speed that is a speed when the brake pedal 11 is moved (returned) to the operation amount reduction side (brake reduction speed detection means). Specifically, the brake ECU 30 calculates the brake reduction speed based on the difference between the brake stroke acquired this time and the brake stroke acquired and stored last time, as in step 404. Further, a plurality of brake strokes acquired and stored before this time may be averaged, and the brake reduction speed may be calculated from the average value.

  In step 410, the brake ECU 30 determines whether or not the brake amount, which is the depression amount of the brake pedal 11, has become zero. That is, the brake ECU 30 determines whether or not the brake pedal 11 has completely returned to the position before the depression (initial position) when the gap S is filled after the brake pedal 11 is returned. The brake ECU 30 acquires the detection result from the brake stroke sensor 11a, and determines that the brake amount has become 0 if the brake stroke that is the detection result is 0.

  Then, the brake ECU 30 temporarily stops the brake control in step 406 (step 412) and sets the brake-off gap opening mode (step 414). This is because “YES” is determined in step 402 from the next time and the program is jumped to the processing of step 420. If the brake stroke is greater than zero, the brake ECU 30 determines that the brake amount is not zero, and advances the program to step 406.

When the brake pedal 11 being depressed is completely returned by the driver (when the brake amount becomes 0), the control to widen the gap S is performed. In other words, the brake ECU 30 calculates a motor current (target motor current value) that is a current value for energizing the electric motor 26 in step 416. The brake ECU 30 calculates a motor current corresponding to the brake reduction speed detected this time from a map (see FIG. 13) showing the relationship between the brake reduction speed and the motor current and the brake reduction speed detected this time.
As shown in FIG. 13, the map showing the relationship between the brake reduction speed and the motor current is set so that the motor current decreases as the brake reduction speed decreases. This is because the probability that the accelerator pedal 12 is immediately operated after the operation amount of the brake pedal 11 becomes 0 is lower as the brake decreasing speed is smaller.

  In step 418, the brake ECU 30 energizes the motor current calculated in step 416 to drive the electric motor 26. At this time, for example, the brake ECU 30 performs PWM control with a duty ratio corresponding to the motor current. That is, when the brake pedal 11 is completely returned, the brake ECU 30 starts the gap opening control by the electric motor 26 at the same time.

  The brake ECU 30 switches the third gap predetermined value to the third specified value or the fourth specified value according to the vehicle state. First, the brake ECU 30 detects the vehicle state in step 420 as in step 114 described above (vehicle state detection means). Next, in Steps 422 to 426, the brake ECU 30 supplies a current to the electric motor 26 to change the gap (the third gap predetermined value) when the vehicle state detected by the vehicle state detection means is a predetermined state. To do. In step 422, the brake ECU 30 determines whether or not the vehicle state detected in step 420 is a predetermined state. In the present embodiment, the predetermined states are a low vehicle speed state and a downhill traveling state.

  If the brake ECU 30 determines that the vehicle state is not the predetermined state, the brake ECU 30 determines “NO” in step 422 and sets the third gap predetermined value to the third specified value (step 424). If the brake ECU 30 determines that the vehicle state is the predetermined state, the brake ECU 30 determines “NO” in step 422 and sets the third gap predetermined value to the fourth specified value (step 426).

  The third predetermined clearance value indicates a predetermined value (target value) of the clearance S when the clearance S is expanded after the brake pedal 11 is returned. The third specified value is set to the same value as the gap formed between the pads 22a and 22b and the rotor 21 after returning to the initial position (the above-described appropriate gap). The fourth specified value is set to a value smaller than the third specified value. For example, the fourth specified value may be set to the same value as the second specified value described above.

  Therefore, when expanding the gap S after the brake pedal 11 is returned, the target value of the gap S is relatively low considering that the probability that the brake pedal 11 will not be operated next is low when the vehicle state is not a predetermined state. It is set to a third specified value that provides a large gap. On the other hand, when the vehicle state is a predetermined state (for example, a low vehicle speed state in a traffic jam or an inertial traveling state on a downhill), it is highly likely that the brake operation is performed at a relatively early timing, so the gap S is reduced in advance. In order to achieve both the viewpoint of suppressing the motor current at the time of the next brake operation and the viewpoint of preventing the drag between the pads 22a and 22b and the rotor 21, the fourth specified value which is a gap smaller than the appropriate gap is set. Is done. Thereby, when the vehicle state detected by the vehicle state detection means is a predetermined state, the electric motor 26 can be energized to change the gap (third gap predetermined value).

In step 428, the brake ECU 30 acquires the clearance S in the same manner as in step 122 described above. When the electric motor 26 is being driven and the gap S reaches the third gap predetermined value, the brake ECU 30 determines “YES” in step 430 and stops the gap opening control. Specifically, the brake ECU 30 determines in step 430 whether or not the gap S is equal to or greater than a third gap predetermined value.
If the clearance S is less than the third clearance predetermined value, the brake ECU 30 determines “NO” in step 430 and temporarily terminates the program. If the gap S is equal to or greater than the third gap predetermined value, the brake ECU 30 determines “YES” in step 430, stops driving the electric motor 26 (step 432), and sets the brake-off gap opening mode. Release (step 434).

  As is apparent from the above, according to the present embodiment, the amount of wear of the brush of the electric motor 26 is proportional to the square of the magnitude of the current flowing through the electric motor 26, and the current flowing through the electric motor 26 is Focusing on the fact that the magnitude of the starting current is extremely large, the gap S between the pads 22a, 22b and the rotor 21 is reduced until the first gap reaches a predetermined value before the brake pedal 11 is operated. . Thus, by reducing the gap S between the pads 22a, 22b and the rotor 21 before the brake pedal 11 is operated, the magnitude of the starting current of the electric motor 26 when the brake pedal 11 is operated can be reduced. Can be small.

Here, the smaller the accelerator decrease speed, the longer the time until the operation amount of the accelerator pedal 12 becomes zero, and the longer the time until the brake pedal 11 is operated after the operation amount of the accelerator pedal 12 becomes zero. It is considered to be. Therefore, in the present embodiment, the smaller the accelerator reduction speed, the smaller the current S is supplied to the electric motor 26, thereby reducing the gap S between the pads 22a, 22b and the rotor 21 until the first gap becomes a predetermined value. Thereby, the magnitude | size of the starting electric current of the electric motor 26 when making the said clearance gap S small before the brake pedal 11 is operated as mentioned above can be made small.
As described above, by reducing the magnitude of the starting current of the electric motor 26, wear of the brush of the electric motor 26 can be suppressed, and the life of the electric motor 26 can be extended.

  Here, when the accelerator pedal 12 is moved to the operation amount increase side, the operation amount of the accelerator pedal 12 is increased, and the probability that the brake pedal 11 is operated is reduced. Therefore, an accelerator operation amount increase detection means (step 304) for detecting that the accelerator pedal 12 is moved to the operation amount increase side is provided, and the motor control means is configured such that the accelerator pedal 12 is operated by the accelerator operation amount increase detection means. When it is detected that the actuator is operating on the increase side, the electric motor 26 is energized to increase the gap S between the pads 22a, 22b and the rotor 21 (step 316). Therefore, when it is detected that the accelerator pedal 12 is operated to increase the operation amount, the electric motor 26 is energized to increase the gap S between the pads 22a, 22b and the rotor 21. . Thereby, drag can be reduced while suppressing wear of the brush of the electric motor 26 (coexistence of suppression of wear of the electric motor 26 and reduction of drag) can be achieved.

  Further, the smaller the accelerator increase speed, the higher the probability that the accelerator pedal 12 will again move toward the operation amount decreasing side. Therefore, an accelerator increase speed detecting means (step 312) for detecting an accelerator increase speed that is a speed when the accelerator pedal 12 is moving toward the operation amount increasing side is provided, and the motor control means is detected by the accelerator increase speed detecting means. The smaller the acceleration increase speed, the smaller the electric current is supplied to the electric motor 26 to increase the gap S between the pads 22a, 22b and the rotor 21 (steps 314, 316). Therefore, a smaller current is supplied to the electric motor 26 to increase the gap S between the pads 22a, 22b and the rotor 21 as the accelerator increase speed is smaller. As a result, when there is a high probability that the accelerator pedal 12 again moves to the operation amount decreasing side, the magnitude of the starting current when the gap S between the pads 22a, 22b and the rotor 21 is increased is reduced. Wear of the brush of the electric motor 26 accompanying the increase in the gap S between 22b and the rotor 21 can be suppressed.

  In addition, a gap acquisition unit (steps 306 and 318) for acquiring the gap S between the pads 22a and 22b and the rotor 21 is provided, and the motor control unit determines that the gap S acquired by the gap acquisition unit is greater than the first gap predetermined value. Is larger than the predetermined value of the second gap, the electric motor 26 is energized to increase the gap S between the pads 22a, 22b and the rotor 21 (steps 312 to 316, 320). As a result, when the gap S between the pads 22a and 22b and the rotor 21 is equal to or less than the second gap predetermined value, that is, when there is a high probability that drag will occur, the electric motor 26 is energized and the pads 22a and 22b The gap S with the rotor 21 is increased. As a result, it is possible to more suitably achieve both suppression of brushing of the electric motor 26 and reduction of drag.

  Moreover, when the predetermined time has passed without the brake pedal 11 being operated after the operation amount of the accelerator pedal 12 becomes zero, the probability that the brake pedal 11 will be operated thereafter is low. In view of this, the time control means (step 210) for measuring the elapsed time after the operation amount of the accelerator pedal 12 becomes zero is provided, and the motor control means is configured such that the brake pedal 11 is operated after the operation amount of the accelerator pedal 12 becomes zero. When the elapsed time measured by the time measuring means without being operated becomes equal to or longer than a predetermined time, the electric motor 26 is energized to increase the gap S between the pads 22a, 22b and the rotor 21 (step 214, 224). Therefore, when a predetermined time elapses without the brake pedal 11 being operated after the operation amount of the accelerator pedal 12 becomes 0, a current is supplied to the electric motor 26 and the gap between the pads 22a and 22b and the rotor 21 is increased. S is increased. As a result, it is possible to more appropriately achieve both brushing suppression and drag reduction of the brush of the electric motor 26.

  Moreover, it may be preferable not to change the clearance S between the pads 22a and 22b and the rotor 21 depending on the vehicle state. Accordingly, vehicle state detection means (step 114) for detecting the vehicle state is provided, and the motor control means supplies a current to the electric motor 26 when the vehicle state detected by the vehicle state detection means is a predetermined state. Thus, the gap S between the pads 22a and 22b and the rotor 21 is changed (steps 116 and 120). Therefore, when the vehicle state is a predetermined state, the electric motor 26 is energized to change the gap S between the pads 22a and 22b and the rotor 21. Thereby, the abrasion of the brush of the electric motor 26 can be suppressed without affecting the braking performance of the vehicle.

  Further, when the brake pedal 11 is operated after the operation amount of the accelerator pedal 12 becomes zero, a brake operation start speed calculating means for calculating a brake operation start speed that is an initial operation speed of the operation (step 218). The motor control means supplies a smaller current to the electric motor 26 as the brake operation start speed calculated by the brake operation start speed calculation means is smaller, and creates a gap S between the pads 22a, 22b and the rotor 21. The first gap is made smaller than a predetermined value (steps 218 to 222, 232). As a result, when the brake pedal 11 is operated after the operation amount of the accelerator pedal 12 becomes zero, a smaller current is supplied to the electric motor 26 as the brake operation start speed is lower, and the pads 22a, 22b and The gap S with the rotor 21 is made smaller than the first gap predetermined value. Thus, the magnitude of the starting current of the electric motor 26 accompanying the start of operation of the brake pedal 11 can be further reduced in accordance with the operation of the brake operation member, and the amount of wear of the brush of the electric motor 26 is further suppressed. be able to.

  By the way, the smaller the brake reduction speed, the lower the probability that the accelerator pedal 12 will be operated immediately after the operation amount of the brake pedal 11 becomes zero. Therefore, in the above-described embodiment, the smaller the brake reduction speed, the larger the gap S between the pads 22a, 22b and the rotor 21 by applying a small current to the electric motor 26 after the operation amount of the brake pedal 11 becomes zero. (Steps 410, 416, and 418). Thereby, since the magnitude | size of the starting electric current of the electric motor 26 when enlarging the said clearance gap S becomes small, the abrasion of the brush of the electric motor 26 can be suppressed.

  Here, depending on the vehicle state, it may be preferable not to change the gap S between the pads 22a and 22b and the rotor 21. Therefore, vehicle state detection means (step 420) for detecting the vehicle state when the brake pedal 11 is moving to the operation amount decreasing side is provided, and the motor control means is configured such that the vehicle state detected by the vehicle state detection means is predetermined. In the state, the electric motor 26 is energized to increase the gap S between the pads 22a and 22b and the rotor 21 (steps 422 and 426). Therefore, when the vehicle state is a predetermined state, the electric motor 26 is energized to change the gap S between the pads 22a and 22b and the rotor 21. Thereby, the abrasion of the brush of the electric motor 26 when the gap S between the pads 22a and 22b and the rotor 21 is increased can be suppressed without affecting the braking performance of the vehicle.

  In the embodiment according to the electric brake device described above, the electric disc brake is adopted, but an electric drum brake may be adopted. In this case, the electric drum brake is held non-rotatably by a drum that is a braked member that rotates integrally with a wheel and a backing plate that is a vehicle body side member, and has a predetermined clearance (interval) with respect to the drum. A brake shoe as a braking member disposed so as to have a DC electric motor that generates a force corresponding to a supplied current, a position sensor that detects the position of the brake shoe, and a pressure sensor The brake shoe is moved (pushed) toward the inner peripheral surface of the drum by the force generated by the electric motor and brought into contact therewith, and the brake shoe is pressed against the inner peripheral surface of the drum. A braking torque that suppresses the rotation of the wheel is generated.

  DESCRIPTION OF SYMBOLS 11 ... Brake pedal (brake operation member), 11a ... Brake stroke sensor (brake depression state detection means), 12 ... Accelerator pedal (acceleration operation member), 12a ... Accelerator opening degree sensor (accelerator depression state detection means), 20 ... Electricity Disc brake, 21 ... Disc rotor (braking member), 22a, 22b ... Brake pad (braking member), 25 ... Piston, 26 ... Electric motor, 30 ... Brake ECU (motor control means, accelerator reduction speed detecting means, accelerator operation) (Amount increase detection means, accelerator increase speed detection means, gap acquisition means, timing means, vehicle state detection means, brake operation start speed calculation means, brake decrease speed detection means), 41 ... wheel speed sensor, 42 ... vehicle speed sensor, 43 ... Gradient sensor, W ... wheel.

Claims (9)

In the electric brake device for a vehicle that generates a braking force by pressing the braking members (22a, 22b) against the member to be braked (21) by an electric motor (26),
An accelerator decelerating speed detecting means (30, step 108) for detecting an accelerator decelerating speed which is a speed when the accelerator operating member (12) is moving toward the operation amount decreasing side;
The smaller the accelerator decelerating speed detected by the accelerator decelerating speed detecting means, the smaller the electric current is supplied to the electric motor, and the gap between the braking member and the braked member is changed before the brake operating member is operated. Motor control means (30, steps 108 to 112, 124) for reducing the clearance until it reaches a predetermined value of one gap;
An electric brake device for a vehicle, comprising: In claim 1,
An accelerator operation amount increase detection means (30, step 304) for detecting that the accelerator operation member is moved to the operation amount increase side;
When the accelerator operation amount increase detecting means detects that the accelerator operation member is operated to the operation amount increase side, the motor control means supplies a current to the electric motor to An electric brake device for a vehicle, wherein a gap with the member to be braked is increased (step 316). The accelerator increasing speed detecting means (30, step 312) for detecting an accelerator increasing speed which is a speed when the accelerator operating member is moving to the operation amount increasing side according to claim 1 or 2,
The motor control means applies a smaller current to the electric motor to increase the clearance between the braking member and the braked member as the accelerator increase speed detected by the accelerator increase speed detecting means is smaller (step S1). 314, 316), an electric brake device for a vehicle. In claim 2 or claim 3,
A clearance acquisition means (30, steps 306, 318) for acquiring a clearance between the braking member and the braked member;
The motor control means applies a current to the electric motor and supplies the braking member when the gap acquired by the gap acquisition means is equal to or smaller than a second gap predetermined value that is larger than the first gap predetermined value. And the braked member (steps 312 to 316, 320). In any one of Claims 1 thru | or 4,
A time measuring means (30, step 210) for measuring an elapsed time after the operation amount of the accelerator operating member becomes zero,
When the elapsed time measured by the time measuring means reaches a predetermined time or more without operating the brake operating member after the operation amount of the accelerator operating member becomes 0, the motor control means An electric brake device for a vehicle characterized by energizing a motor to increase a gap between the braking member and the braked member (steps 208, 214, and 224). In any one of Claims 1 to 5,
Vehicle state detecting means (30, step 114) for detecting the vehicle state;
When the vehicle state detected by the vehicle state detection unit is a predetermined state, the motor control unit applies a current to the electric motor to change a gap between the braking member and the braked member ( Steps 116 and 120). An electric brake device for vehicles. In any one of Claims 1 thru | or 6,
When the brake operation member is operated after the operation amount of the accelerator operation member becomes zero, a brake operation start speed calculation means (30, step) that calculates a brake operation start speed that is an initial operation speed of the operation is performed. 218),
The motor control means applies a smaller current to the electric motor as the brake operation start speed calculated by the brake operation start speed calculation means is smaller, and sets a gap between the braking member and the braked member. An electric brake device for a vehicle, wherein the first gap is made smaller than a predetermined value (steps 218 to 222, 232). In the electric brake device for a vehicle that generates a braking force by pressing the braking members (22a, 22b) against the member to be braked (21) by an electric motor (26),
Brake reduction speed detection means (30, step 408) for detecting a brake reduction speed that is a speed at which the brake operation member (11) moves to the operation amount decrease side;
The smaller the brake reduction speed detected by the brake reduction speed detection means, the smaller the operation amount of the brake operation member becomes 0, and then a smaller current is applied to the electric motor to cause the braking member and the braked member to Motor control means (30, steps 410, 416, 418) for increasing the gap;
An electric brake device for a vehicle, comprising: In claim 8,
Vehicle state detection means (30, step 420) for detecting a vehicle state when the brake operation member is moving toward the operation amount decreasing side;
The motor control means energizes the electric motor to increase a gap between the braking member and the braked member when the vehicle state detected by the vehicle state detection means is a predetermined state (step) 422, 426). An electric brake device for a vehicle.

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