JP5170462B2 - Electric brake device - Google Patents

Description

  The present invention relates to an electric brake device that generates a braking force by an electric actuator.

  With the recent development of electronic technology, various electric brake devices have been proposed that electrically detect the depression state of a driver's brake pedal and generate an braking force by driving an electric motor according to the detected depression state. Yes. The electric brake device reciprocates a piston by driving an electric motor, and presses a brake pad connected to the piston against a brake rotor to obtain a braking force.

  For this reason, by controlling the driving power of the electric motor, a braking state having an arbitrary characteristic can be obtained, and a braking device having a braking characteristic according to the driver's intention or request with a high degree of freedom. Can do.

  In order to reliably obtain a desired braking force by utilizing such characteristics, it is necessary to obtain a braking force by contacting the brake rotor and the brake pad with good responsiveness to the operation of the brake pedal. By making the gap between the brake rotor and the brake pad small, the responsiveness at the start of braking can be improved.

  On the other hand, if the clearance between the brake rotor and the brake pad is too small, the brake pad will come into contact with the brake rotor even during non-braking and a dragging condition will occur, resulting in running resistance and increased wear on the brake pad. It will end up.

  Under such circumstances, there is a need for an electric brake device that can secure a gap between the brake rotor and the brake pad during non-braking and has a characteristic that the brake rotor and the brake pad come into contact with each other with good responsiveness to the operation of the brake pedal during braking. .

  In an electric brake device that allows power transmission of an electric motor by a band brake device, a technique is known in which the electric motor is driven in advance and the band brake device is operated by operating a brake pedal to improve the responsiveness at the start of braking. (For example, refer to Patent Document 1).

  However, in an electric brake device in which the electric motor is directly attached to a member on the vehicle body side and the movement of the brake pad is controlled only by the operation of the electric motor, the electric motor is operated to manage the gap between the brake rotor and the brake pad. It is necessary to devise, and it is structurally impossible to increase the responsiveness by driving the electric motor in advance.

JP 2005-114005 A

  The present invention has been made in view of the above situation, and in an electric brake device in which an electric actuator is directly attached to a member on the vehicle body side and the braking state is controlled by the operation of the electric actuator, the gap between the brake pad and the brake rotor is accurately determined. It is an object of the present invention to provide an electric brake device that can be managed and that can improve the response during braking.

  In order to achieve the above object, an electric brake device according to a first aspect of the present invention is an electric brake that obtains a braking force by driving a piston of an electric actuator in response to an operation of a brake pedal and pressing a brake pad against a brake rotor. In the apparatus, when the brake pedal is operated in a first predetermined state, the piston is driven so that the brake pad comes into contact with the brake rotor, and the driving of the piston is stopped. When the brake pedal is operated to a second predetermined state on the brake side with respect to the predetermined state, the brake starting means for driving the piston according to the operation of the brake pedal, and the second state from the state of the braking operation. When the brake pedal is operated in a predetermined state, the driving of the piston is stopped, and the driving of the piston is stopped. When serial first of said brake pedal to a predetermined state is operated, the brake pad, characterized in that the piston in a state away from the brake rotor and a terminal braking means driven by a predetermined amount.

  According to the first aspect of the present invention, when the brake pedal is operated to the first predetermined state, the piston is driven so that the brake pad comes into contact with the brake rotor, assuming that the braking operation is started immediately after. When the brake pedal is operated to the second predetermined state on the braking side, the braking start means drives the piston in accordance with the operation of the brake pedal to perform a desired braking operation. When the braking operation is finished and the brake pedal is returned to the second predetermined state, the driving of the piston is stopped, and when the driving of the piston is stopped, the brake pedal is further returned to the first predetermined state. The brake pad is returned to the state of being separated from the brake rotor by the braking end means.

  For this reason, the clearance between the brake pad and the brake rotor can be managed accurately, and the responsiveness can be improved during braking.

  The piston is driven by a predetermined amount from the state where the brake pad is in contact with the brake rotor to the state where the brake pad is separated from the brake rotor, and the position where the predetermined amount is driven is preset as the initial position of the piston. ing.

  The electric brake device according to a second aspect of the present invention is the electric brake device according to the first aspect, wherein the electric actuator is an electric motor in which the piston reciprocates as the drive shaft rotates forward and backward. Rotation angle detection means for detecting the rotation angle of the drive shaft is provided, and the drive amount of the piston is set based on the detection value of the rotation angle detection means.

  In the present invention according to claim 2, the movement amount of the piston is set by detecting the rotation angle of the electric motor.

  An electric brake device according to a third aspect of the present invention is the electric brake device according to the second aspect, wherein the braking start means drives the piston in response to an operation of the brake pedal. It has a recognition function for recognizing the relationship between the command power and the brake level when the brake level with respect to the command power to the motor does not follow.

  According to the third aspect of the present invention, when the degree of braking with respect to the instruction power to the electric motor does not follow, for example, when a desired braking force cannot be obtained due to overheating or wear of the brake pad, the recognition function and the instruction power Recognize the degree relationship. As a recognition function, a deceleration is detected by a sensor and fed back. When the desired braking force is not obtained, it is desirable to display the fact that the brake device is in a severe state. It is also possible to implement control to increase the braking force so that the braking degree according to the command power is within the range of safe operation of the brake device.

  The electric brake device according to the present invention makes it possible to accurately manage the gap between the brake pad and the brake rotor in the electric brake device in which the braking situation is controlled by the operation of the electric actuator, and to improve the response at the time of braking. It becomes possible to increase.

1 is a schematic configuration diagram of an electric brake device according to an embodiment of the present invention. It is a block block diagram. It is a control flowchart. It is a control flowchart. It is a time chart. It is a control map. It is a control map. It is a control map.

  The configuration of the electric brake device will be described with reference to FIG. FIG. 1 shows a schematic cross-section for explaining the configuration of an electric brake device according to an embodiment of the present invention.

  As shown in the figure, a brake rotor 1 that rotates together with wheels is provided, and the brake rotor 1 is pressed by a pair of brake pads 2 to generate a braking force and a deceleration force by a frictional force. That is, the caliper 3 is supported on the vehicle body side so as to be reciprocally movable (left and right in the figure), and the electric motor 4 that is an electric actuator is fixed to the caliper 3. A piston 5 is slidably fitted to the caliper 3.

  A nut member 6 is fixed inside the piston 5, and a screw portion provided on the drive shaft 7 of the electric motor 4 is screwed into the nut member 6. When electric power is supplied to the electric motor 4, the drive shaft 7 rotates forward and backward, and the piston 5 is driven to reciprocate in the axial direction (left and right in the figure) via the nut member 6. Brake pads 2 are respectively provided on the caliper 3 facing one surface (the left surface in the drawing) of the brake rotor 1 and the tip portion of the piston 5 facing the other surface (the right surface in the drawing) of the brake rotor 1. Is attached.

  For example, when the drive shaft 7 of the electric motor 4 rotates in the forward direction, the piston 5 is driven in the left direction in the figure, and the brake pad 2 attached to the piston 5 is pressed against the brake rotor 1 and at the same time the caliper 3. Slides rightward in the figure due to the reaction force, and the brake rotor 1 is pressed by the pair of brake pads 2. Thereby, braking force and deceleration force are generated. For example, when the drive shaft 7 of the electric motor 4 rotates in the reverse direction, the pair of brake pads 2 are separated from the brake rotor 1. Thereby, braking force and deceleration force are released.

  A control unit (ECU) 8 for controlling the electric motor 4 is provided, and brake pedal operation information (operation amount, operation speed) is input to the ECU 8. A control signal (current value command signal) is sent from the ECU 8 to the electric motor 4 in accordance with the brake pedal operation information, and the rotation direction and the rotation speed of the drive shaft 7 are controlled.

  The electric motor 4 is provided with a rotation angle sensor 9 that detects the rotation angle of the drive shaft 7 and a current detection sensor 10 that detects a drive current. The rotation angle of the drive shaft 7 and the current value of the electric motor 4 are detected, and the rotation angle and the current value are input to the ECU 8 and feedback controlled.

  In the electric brake device described above, when the driver's braking operation is detected, the drive shaft 7 of the electric motor 4 is rotated in the forward direction, the brake pad 2 is brought into contact with the brake rotor 1 to make the gap zero, The operation of the electric motor 4 is stopped. When the braking operation further proceeds and the start of braking is detected, the brake pad 2 is pressed against the brake rotor 1 from the state where the gap is zero. Thereby, responsiveness can be accelerated and a braking force can be obtained.

  Further, the operation of the electric motor 4 is stopped when the braking operation is performed and the braking start time is detected, and further, the driving shaft 7 of the electric motor 4 is detected when the driver braking operation time is detected. Is rotated in the reverse direction to ensure a predetermined gap between the brake rotor 1 and the brake pad 2. Thereby, dragging of the brake pad 2 during traveling can be eliminated, fuel consumption can be improved, and wear of the brake pad 2 can be reduced.

  The ECU 8 will be described in detail with reference to FIGS. FIG. 2 shows a block configuration of the ECU 8 for accelerating responsiveness and setting a predetermined gap when releasing the brake.

  The ECU 8 is provided with braking start means 11. The braking start means 11 drives and rotates the drive shaft 7 of the electric motor 4 in the forward direction when the operation amount PS of the brake pedal becomes equal to or greater than the first threshold value SP1 which is the first predetermined state. This is means for stopping the driving of the piston 5 by bringing the brake pad 2 into contact with the brake rotor 1. The contact of the brake pad 2 catches and recognizes the increase in the current value of the electric motor 4.

  Then, the braking start means 11 performs braking when the operation amount PS of the brake pedal becomes equal to or greater than the second threshold value SP2, which is the second predetermined state on the braking side with respect to the first threshold value SP1. This is means for obtaining a desired braking force by driving the piston 5 in accordance with the pedal operation amount PS.

  Further, the ECU 8 is provided with a braking end means 12. The braking end means 12 is a means for stopping the electric motor 4 when the operation amount PS of the brake pedal is returned to a state below the second threshold value SP2 from the state of the braking operation.

  Then, the braking end means 12 is configured such that when the operation amount PS of the brake pedal is returned to a state below the first threshold value SP1 while the electric motor 4 is stopped, the brake pad 2 is moved to the brake rotor. This is means for driving and rotating the piston 5 of the electric motor 4 in the reverse direction so as to be separated from 1. The piston 5 is driven by a predetermined amount, and a predetermined gap is secured between the brake pad 2 and the brake rotor 1.

  For this reason, it is possible to obtain a braking force by increasing the responsiveness at the start of braking, eliminating dragging of the brake pad 2 during traveling after braking, improving fuel consumption, and reducing wear of the brake pad 2. . Accordingly, the gap between the brake pad 2 and the brake rotor 1 can be managed accurately, and the response can be improved during braking.

  The rotation angle of the drive shaft 7 of the electric motor 4 is detected by the rotation angle sensor 9, and the movement amount of the piston 5 is set based on the detection value of the rotation angle sensor 9. Detection information of the rotation angle sensor 9 and detection information of the current detection sensor 10 are input to the ECU 8. Further, information on the deceleration of the vehicle is input to the ECU 8 as information on a deceleration sensor, for example, and the degree of braking is derived. The ECU 8 is provided with an electric brake driving means 13 and outputs a control signal (current value command signal) to the electric motor 4.

  When the braking start means 11 of the ECU 8 drives the piston 5 of the electric motor 4 in response to the operation of the brake pedal, if the braking degree with respect to the instruction power to the electric motor 4 does not follow, the relationship between the instruction power and the braking degree Has a recognition function. When it is recognized that the braking degree derived from the deceleration information does not follow the braking force when the electric motor 4 is driven based on the command power, the display means 14 displays that fact.

  For example, although the command power corresponding to the operation of the brake pedal is sent to the electric motor 4 due to overheating or wear of the brake pad, a desired braking force corresponding to the command power is not obtained (braking degree) If it is recognized that the brake device is in a severe condition, the display means 14 is turned on to indicate that the condition is a severe condition.

  If it is recognized that a desired braking force according to the command power is not obtained, control is performed to increase the braking force within the range of safe operation of the brake device so that the degree of braking according to the command power is achieved. Is also possible.

  Further, in the braking start means 11 of the ECU 8, the total drive angle MAR of the drive shaft 7 of the electric motor 4 from the reference position of the piston 5 until the brake pad 2 comes into contact with the brake rotor 1 exceeds the predetermined drive angle MARS. In this case, it is determined that the brake pad 2 (brake rotor 1) is worn, and information is sent to an alarm 15 such as a display lighting.

  The operation of the electric brake device described above will be specifically described with reference to FIGS.

  3 and 4 are flowcharts for explaining the flow of control processing of the electric brake device, FIG. 5 is an operation amount (a) of the brake pedal, a rotation angle (b) of the drive shaft 7 of the electric motor 4, and the electric motor 4. Is a time chart for explaining changes over time in the current value (c), the gap (d) between the brake rotor 1 and the brake pad 2, and the braking deceleration (e). 6 shows the relationship between the motor current and the operation amount of the brake pedal, FIG. 7 shows the relationship between the motor current and the operation speed of the brake pedal, and FIG. 8 shows the relationship between the braking deceleration and the motor current.

  As shown in FIG. 3, it is determined in step S1 whether or not the operation amount PS of the brake pedal is equal to or greater than a first threshold value SP1 (an operation amount that is started immediately after the braking operation). Is determined to be greater than or equal to the first threshold value SP1 (t1 in FIG. 5 (a)), the electric motor 4 is rotated forward in step S2 (FIG. 5 (b) braking direction). If it is determined in step S1 that the operation amount PS of the brake pedal is lower than the first threshold value SP1, the process proceeds to FIG. 5 and ends (A).

  Whether the electric motor 4 is rotated forward and the current value (motor current value MI) of the electric motor 4 detected by the current detection sensor 10 (see FIG. 1) exceeds a predetermined current value (motor current predetermined value MIA). Is determined in step S3 (see FIG. 5C). If it is determined in step S3 that the motor current value MI is equal to or less than the predetermined motor current value MIA, the brake pad 2 is not in contact with the brake rotor 1, so the forward rotation of the electric motor 4 is continued in step S2.

  If it is determined in step S3 that the motor current value MI has exceeded the predetermined motor current value MIA (see FIG. 5C), the electric motor 4 is stopped in step S4. That is, when the brake pedal reaches an operation amount at which braking is started (when the intention of braking is applied), the brake pad 2 is brought into contact with the brake rotor 1 to stop the electric motor 4.

  After stopping the electric motor 4 in step S4, it is determined in step S5 whether or not the brake pedal operation amount PS is greater than or equal to a second threshold value SP2 (operation amount that actually requires braking). When it is determined that PS is greater than or equal to the second threshold value SP2 (t2 in FIG. 5A), assuming that the braking operation is started immediately, the process proceeds to step S6 and the brake pedal operation amount PS is set. The operation proceeds to an operation for obtaining a desired braking force.

  If it is determined in step S5 that the operation amount PS of the brake pedal is less than the second threshold value SP2, whether or not the operation amount PS of the brake pedal is greater than or equal to the first threshold value SP1 is determined in step S7. If it is determined that the manipulated variable PS is less than the first threshold value SP1, it is determined that there is no intention of braking, and the process proceeds to FIG. 5 and ends (A). If it is determined in step S7 that the brake pedal operation amount PS is greater than or equal to the first threshold value SP1, the process of step S5 is repeated until the brake pedal operation amount PS is greater than or equal to the second threshold value SP2. (Between t1 and t2 in FIG. 5A).

  Therefore, when the brake pedal is operated to be equal to or greater than the first threshold value SP1, it is assumed that the braking operation is started immediately after that, the piston 5 is driven so that the brake pad 2 contacts the brake rotor 1, and the braking operation is performed. Can speed up the response. In this case, as shown in FIG. 5 (d), the gap between the brake pad 2 and the brake rotor 1 becomes zero, and the braking deceleration rate α has not yet been obtained as shown in FIG. 5 (e).

  Returning to FIG. 3, when it is determined in step S5 that the operation amount PS of the brake pedal is equal to or greater than the second threshold value SP2, it is determined that the intention of braking is applied, and in steps S6, S8, and S9, the brake is applied. A motor current MI is set based on the pedal operation amount PS (proportional characteristic: PS characteristic) and the operation speed (differential characteristic: DPS characteristic), and supplied to the electric motor 4 as an instruction current.

  That is, in step S6, the motor current MIPS based on the proportional characteristic and the motor current MIDPS based on the differential characteristic are read. As shown in FIG. 6, the motor current MIPS based on the proportional characteristic is mapped and stored in relation to the operation amount PS of the brake pedal. Further, as shown in FIG. 7, the motor current MIDPS based on the differential characteristics is mapped and stored in relation to the operation speed of the brake pedal.

  As shown in FIG. 6, the motor current MIPS increases linearly as the brake pedal operation amount PS increases, and as shown in FIG. 7, the motor current MIDPS gradually increases in a region where the brake pedal operation speed is slow. However, the motor current MIDPS increases rapidly in the region where the operating speed of the brake pedal is fast.

  After the motor current MIPS based on the proportional characteristics and the motor current MIDPS based on the differential characteristics are read, in step S8, the motor current MIPS and the motor current MIDPS are added to obtain the instruction motor current MI. In S9, the electric motor 4 is operated by the obtained motor current MI.

  Since the motor current MI for instruction is set by the motor current MIPS (operation amount component) based on the proportional characteristics and the motor current MIDPS (operation speed component) based on the differential characteristics, When the brake pedal is operated greatly quickly, the instruction motor current MI can be increased to obtain a sufficient braking force according to the situation.

  While the operation of the electric motor 4 is started in step S9 and braking is being executed (between t2 and t3 in FIG. 5A), the process shown in FIG. 4B is performed based on the motor current MI. It is determined whether or not the braking degree derived from the deceleration information follows the braking force (braking deceleration α) when the electric motor 4 is driven, and the brake pad 2 (brake rotor 1 ) Wear state is determined.

  As shown in FIG. 4, it is determined in step S10 whether the braking deceleration rate α is equal to or less than (Ga · MI-b). As shown in FIG. 8, the braking deceleration rate α is set to a value obtained by multiplying the motor current MI by the driver sensitivity setting value Ga (shown by a solid line in the figure), and when operating with the motor current MI. The threshold value of the braking force (braking deceleration rate α) lower than the braking force of (Ga · MI−b) is set (indicated by a dotted line in the figure).

  Therefore, in step S10, it is determined whether or not the braking deceleration rate α is equal to or less than the threshold value (Ga · MI-b), and the actually requested braking deceleration rate α becomes a predetermined braking deceleration rate α. It is determined whether or not it is following.

  If it is determined in step S10 that the braking deceleration rate α is equal to or less than (Ga · MI−b), the braking force when the electric motor 4 is driven based on the motor current MI is derived from the deceleration information. It is determined that the applied braking degree does not follow.

  For example, if the brake pad 2 (brake rotor 1) is overheated or worn during braking on a long downhill, the motor current MI corresponding to the operation of the brake pedal is sent to the electric motor 4 regardless of whether the brake pad 2 (brake rotor 1) is overheated or worn. There is a possibility that a desired braking force according to the motor current MI is not obtained. If such a situation occurs, it is determined that the braking deceleration rate α is (Ga · MI-b) or less.

  Returning to the flowchart, when it is determined in step S10 that the braking deceleration rate α is equal to or less than (Ga · MI−b), in step S11, the increment MIb is added to the motor current MI to obtain a new motor current MI. Set. After setting the motor current MI including the increment MIb in step S11, the display unit 14 is turned on in step S12. That is, the display means 14 displays that the brake device is in a severe situation.

  If it is determined in step S10 that the braking deceleration rate α exceeds (Ga · MI-b), the display unit 14 is turned off in step S13, and the increase MIb is reduced from the motor current MI in step S13a (MI = Execute MI-MIb), and check whether the severe condition has improved. When the severe condition is not improved, MIb is added again in the next loop, and the display lamp is turned on. Since this is repeated, the display lamp blinks and hunting occurs in the deceleration of the vehicle body so that the driver can be informed of the severe condition. If the severe condition is improved, the motor current MI returns to the initial MI, so that the display means 14 is turned off so as not to indicate that the situation is severe. Here, the initial value of MIb is set to zero.

  After the display means 14 is turned on in step S12 or after the display means 14 is turned off in step S13, the wear state of the brake pad 2 (brake rotor 1) is determined in step S14.

  That is, in step S14, whether or not the total drive angle MAR of the drive shaft 7 of the electric motor 4 from the reference position of the piston 5 until the brake pad 2 contacts the brake rotor 1 is equal to or less than the predetermined drive angle MARS. Is judged. When it is determined that the total drive angle MAR is not less than or equal to the predetermined drive angle MARS, that is, the total drive angle MAR exceeds the predetermined drive angle MARS, the piston 5 until the brake pad 2 contacts the brake rotor 1 It is determined that the brake pad 2 (brake rotor 1) is worn. Then, wear information is sent to the alarm 15 in step S15.

  The above processing is executed between t2 and t3 in FIG. 5A, and the electric motor 4 is driven by the motor current MI (see FIG. 5C) according to the operation of the brake pedal (see FIG. 5A). Actuates (see FIG. 5B), and the braking force (deceleration α: see FIG. 5E) is controlled. As shown in FIG. 5 (d), the gap between the brake pad 2 and the brake rotor 1 is zero after the brake pedal operation amount PS exceeds the first threshold value PS1.

  Returning to the flowchart, after the wear of the brake pad 2 (brake rotor 1) is determined in step S14 (after the wear information is sent to the alarm 15 in step S15), the brake pedal operation amount PS is set to the second in step S16. It is determined whether or not the threshold value SP2 is exceeded. That is, it is determined whether or not an operation state for terminating braking has been reached.

  If it is determined in step S16 that the operation amount PS of the brake pedal has fallen below the second threshold value SP2 (t3 in FIG. 5A), the electric motor 4 is stopped in step S17 (see FIG. 5B). ). If it is determined in step S16 that the operation amount PS of the brake pedal is not less than the second threshold value SP2, the process proceeds to step S6 shown in FIG. 3 (C), and the motor current corresponding to the operation of the brake pedal. The braking operation for setting MI is continued (processing between t2 and t3 in FIG. 5A).

  After stopping the electric motor 4 in step S17, it is determined in step S18 whether or not the brake pedal operation amount PS has fallen below the first threshold value SP1. That is, it is determined whether or not the operating state before the start of braking is restored. If it is determined in step S18 that the operation amount PS of the brake pedal is not less than the first threshold value SP1, the process proceeds to step S16 to repeat the determination as to whether or not the operation state for ending braking has been reached (FIG. 5 (between t3 and t4).

  On the other hand, when it is determined that the brake pedal operation amount PS is lower than the first threshold value SP1 in step S18 when the electric motor 4 is stopped (t4 in FIG. 5A), in step S19. The electric motor 4 is reversely rotated by a predetermined amount of rotation angle Af (return direction in FIG. 5B). By reversely rotating the rotation angle Af, a predetermined gap is secured between the brake rotor 1 and the brake pad 2 (see FIG. 5D), and the process is completed.

  Therefore, when the brake pedal is returned from the braking operation state to the operation state for ending the braking, a predetermined gap is created between the brake rotor 1 and the brake pad 2 to eliminate dragging of the brake pad 2 during traveling and improve fuel efficiency. Therefore, wear of the brake pad 2 can be reduced.

  By the above processing, the brake pad 2 can be brought into contact with the brake rotor 1 in a state where the braking operation is started immediately, and the response at the time of the braking operation can be accelerated. Further, when the brake pedal is returned from the braking operation state to the state where the braking is finished, a gap is secured between the brake pad 2 and the brake rotor 1, and the drag of the brake pad 2 during traveling can be surely prevented. .

  For this reason, the electric brake device described above can achieve both accurate management of the gap between the brake pad 2 and the brake rotor 1 and realization of high responsiveness during braking.

  The present invention can be used in the industrial field of an electric brake device that generates a braking force by an electric actuator.

DESCRIPTION OF SYMBOLS 1 Brake rotor 2 Brake pad 3 Caliper 4 Electric motor 5 Piston 6 Nut member 7 Drive shaft 8 Control unit (ECU)
DESCRIPTION OF SYMBOLS 9 Rotation angle sensor 10 Current detection sensor 11 Braking start means 12 Braking end means 13 Electric brake drive means 14 Display means 15 Alarm

Claims (3)

In the electric brake device that drives the piston of the electric actuator according to the operation of the brake pedal and obtains the braking force by pressing the brake pad against the brake rotor,
When the brake pedal is operated in the first predetermined state, the piston is driven so that the brake pad comes into contact with the brake rotor, and the driving of the piston is stopped. From the first predetermined state, Braking start means for driving the piston in response to the operation of the brake pedal when the brake pedal is operated in a second predetermined state on the braking side;
When the brake pedal is operated from the braking operation state to the second predetermined state, the driving of the piston is stopped, and the brake is returned to the first predetermined state in a state where the driving of the piston is stopped. An electric brake device comprising: a brake end means for driving the piston by a predetermined amount so that the brake pad is separated from the brake rotor when a pedal is operated. The electric brake device according to claim 1, wherein
The electric actuator is an electric motor in which the piston reciprocates as the drive shaft rotates forward and backward,
A rotation angle detecting means for detecting a rotation angle of the drive shaft;
An electric brake device characterized in that a drive amount of the piston is set based on a detection value of the rotation angle detection means. The electric brake device according to claim 2,
The braking start means includes
When the piston is driven in accordance with the operation of the brake pedal, a recognition function for recognizing the relationship between the command power and the brake level when the brake level with respect to the command power to the electric motor does not follow is provided. Electric brake device characterized by.

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