JP2000283198A - Electric brake device - Google Patents

Abstract

(57) [Problem] To provide an electric brake device capable of preventing a decrease in pad performance even when the vehicle is not used for a long time during running. SOLUTION: The vehicle has travel detection means for detecting whether or not the vehicle is traveling, and accelerator pedal operation state detection means for detecting an accelerator pedal off operation.
When the accelerator pedal operation state detecting means detects that the accelerator pedal has been turned off and the running detecting means detects that the vehicle is running, the clearance between the pad and the disc is reduced, and the pad is slightly moved to the disc. Control the motor to make contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric brake device suitable for use in a vehicle.

[0002]

2. Description of the Related Art In a conventional hydraulic brake system, the return of a piston of a caliper that presses a brake pad depends on the rollback action of a piston seal. The clearance with the rotor may not be constant. Therefore, in this case, a so-called drag, in which the brake pad comes into contact with the disk, may occur even when the brake pedal is not operated due to the surface runout or thickness variation of the brake rotor. As a result, dragging of the brake pad causes the brake pad to be worn even when the brake pedal is not operated, and also reduces fuel economy during driving and impairs economic efficiency. It also causes.

Therefore, in order to solve the above-mentioned problem, an electric brake device has been proposed instead of a hydraulic brake device. This type of electric brake device includes a motor, a conversion mechanism that converts the rotational motion of the motor into a linear motion of a piston, position detecting means that detects a stroke position of the piston from a rotational position of the motor, and the like, Control means for controlling the motor based on the detection result of the means, and the pad is pressed against the disk by linear motion of the piston to generate a braking force. In a vehicle, such an electric brake device is disposed on each wheel.

[0004] In the electric brake device, the advance / retreat position of the pressing member of the brake pad of the caliper, that is, the advance / retreat position of the brake pad can be controlled by driving and controlling the electric actuator. During operation, the brake pad can be retracted to an initial position having a predetermined clearance with respect to the disk rotor so that no drag occurs. Therefore, the problem of the hydraulic brake device described above can be solved.

[0005]

By the way, as described above, in the conventional electric brake device, when the brake pedal is not operated, the brake pad is retracted to the initial position having a predetermined clearance with respect to the disk rotor. When the electric brake device is not used for a long time while driving, dust and moisture between the disc and the pad accumulate, and the pad performance of the electric brake device is used properly. However, there is a problem that it is reduced as compared to

The present invention has been made under such a background, and an object of the present invention is to provide an electric brake device capable of preventing a decrease in pad performance even when the vehicle is not used for a long period of time while traveling. .

[0007]

In order to achieve the above object, an electric brake device according to the present invention comprises a motor, a conversion mechanism for converting a rotational motion of the motor into a linear motion of a piston, and a stroke position of the piston. And a control means for controlling the motor based on the detection result of the position detection means, wherein the linear motion of the piston presses the pad against the disc to generate a braking force. A driving detection unit that detects whether the vehicle is running; and an accelerator pedal operation state detection unit that detects an accelerator pedal off operation, wherein the control unit detects the accelerator pedal operation state. Means for detecting that the accelerator pedal has been turned off by the means, and detecting that the vehicle is traveling by the travel detection means. Stuffed with clearance between the disc, the pad is a control means controls the motor so as to slightly contact with the disk.

Thus, when the accelerator pedal is turned off and the vehicle is detected to be running, the motor closes the clearance between the pad and the disc so that the pad makes slight contact with the disc. Since the motor is controlled in a short time, the space between the pad and the disk is temporarily brought into a so-called drag state, so that dust and moisture between the disk and the pad are removed. Moreover, the pad and the disk are brought into contact only when the vehicle is running and the accelerator pedal is turned off, that is, when the driver has no intention to accelerate. The driver does not feel a sense of incongruity that occurs when the driver is brought into contact with the vehicle.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the electric brake device according to the present invention will be described below with reference to the drawings. An electric brake device 11 according to the present embodiment includes a carrier 12 fixed to a non-rotating portion of a vehicle, and a pair of slidably supported carriers 12 slidably mounted on both sides in the axial direction of a disk 13. Inner pad 14 and outer pad 15
And carrier 12 at two sliding guides (not shown).
And a caliper 17 that is supported so as to be slidable in the axial direction of the disk 13 and that can hold the pads 14 and 15 from both sides.

The carrier 12 has a first connecting portion 22a and a second connecting portion 22b which are arranged substantially in parallel with each other.
And two support portions (not shown) for connecting the respective ends of the first connection portion 22a and the second connection portion 22b to each other. Then, the carrier 12 is fixed to the vehicle body in a state where the carrier is disposed with respect to the disc 13 such that the support portions are located at both ends in the circumferential direction of the disc 13. Note that a sliding guide is provided on each support.

A pair of pad guides (not shown) are provided at positions inside the support portions of the carrier 12 so as to face each other. The pad guides allow the inner pad 14 and the outer pad 15 to move in the axial direction of the disk 13. At both end positions so as to be slidable along. In this support state, the inner pad 14 and the outer pad 15
The rotation about the axis parallel to the axis is restricted.

The caliper 17 includes a substantially cylindrical tubular member 25.
And a housing 28 having a bottom member 26 fixed to one side of the tubular member 25 to close it, and a tip member 27 fixed to the other side of the tubular member 25.

The housing 28 includes a motor 33,
A ball screw (conversion mechanism) 34 for converting the rotational movement of the motor 33 into a linear movement is provided. Motor 3
Reference numeral 3 denotes a housing 28, a coil 35 attached to the inner peripheral portion of the tubular member 25, and a tip end member 27 attached to an end surface of the tubular member 25 opposite to the bottom member 26. It has a bearing 36, a nut member 37 of a ball screw 34 rotatably supported via the bearing 36, and a magnet 38 fixed to an outer peripheral portion of the nut member 37 so as to be located inside the coil 35. I have.

The ball screw 34 has a female thread 37 at its inner periphery.
a nut portion 37 formed with an a.
The screw member 40 has a ball 41 interposed between the female screw portion 37a of the nut member 37 and the male screw portion 40a of the screw member 40.

Here, the screw member 40 and the inner pad 14 are provided with a detent portion 43 for restricting the relative rotation thereof while allowing them to be separated by a predetermined amount along the axial direction of the disk 13. With the screw member 40
Is restricted from rotating about an axis parallel to the axis of the disk 13. The locking portion 43 includes a groove 44 formed in the screw member 40 and a protrusion 45 formed on the inner pad 14 so as to slidably fit in the groove 44.

A cylinder hole 46 is formed in the bottom member 26 so as to be coaxial with the axis of the motor 33, and a hydraulic piston 47 that can contact the screw member 40 is slidable in the cylinder hole 46. Is fitted. And the bottom member 26
Is formed with a port 49 for communicating a chamber 48 formed by the hydraulic piston 47 and the cylinder hole 46 to the outside. A seal member 50 is provided on the outer peripheral portion of the hydraulic piston 47 to seal a gap with the inner peripheral portion of the cylinder hole 46.

A tip member 27 is fixed to an end of the cylindrical member 25 opposite to the bottom member 26. The tip member 27 has a substantially cylindrical tube portion 51 fixed substantially coaxially to the cylindrical member 25, and extends from one side in the radial direction of the tube portion 51 to the opposite side to the cylindrical member 25. And a cylindrical portion 51 from the tip side of the disk path portion 52.
And a claw portion 53 extending so as to be opposed.

The above-described bearing 36 is fitted to the inner peripheral portion of the cylindrical portion 51 of the tip member 27, and the bearing 3
A mounting member 55 that fixes the bearing 36 to the end face of the tubular member 25 is fixed in the vicinity of the mounting member 55. The mounting member 55 is provided with a nut member 37 by detecting the rotational position of the rotating disk 56 fixed to the nut member 37.
, A position detector (position detecting means) 57 for detecting the stroke position of the screw member 40 as a result is fixed.

When the caliper 17 is supported by the carrier 12, the motor 33 and the ball screw 34 have their respective axes parallel to the axis of the disk 13, and the screw member 40 of the ball screw 34 The distal end member 27 extends so that the disk path portion 52 straddles the outer peripheral portion of the disk 13, and the claw portion 53 is opposite to the disk 13 of the outer pad 15. Are arranged so as to be able to abut against each other.

A ball screw 3 is provided between the inner peripheral portion of the mounting member 55 and the outer peripheral portion of the screw member 40 of the ball screw 34.
A dust boot 59 is provided to prevent dust and the like from entering the threaded portion 4 and the like.

As shown in FIG. 2, the electric brake device 11 having the above structure is provided for each of the front, rear, left and right wheels of the vehicle.
One motor 33 and a position detector 57 are connected to a controller (control means) 60. Here, each motor 33 is connected to a motor driver (not shown) provided in the controller 60 to drive each motor.

In FIG. 2, reference numeral 63 denotes a brake pedal to which an operation input is made by the driver, reference numeral 64 denotes a brake operation amount detection sensor for detecting the operation amount of the brake pedal 63, and reference numeral 65 denotes the brake pedal 63. The master cylinder that generates brake fluid pressure by the input of
Reference numeral 6 denotes an alarm lamp for notifying the driver by display. Of all the electric brake devices 11, the one arranged on the front two wheels includes a master cylinder 65.
Is introduced into the chamber 48 via the port 49. Note that the brake fluid pressure from the master cylinder 65 is not introduced into the electric brake device 11 disposed on the rear two wheels, so that the configuration without the chamber 48, the port 49, and the hydraulic piston 47 can be adopted.

Next, the operation of the above-described electric brake device will be described with reference to the flowchart shown in FIG. When an ignition switch (not shown) is turned on, the controller 60 proceeds to step S1 shown in FIG. 3 and resets a timer (not shown) (not shown).
Proceed to step S2. In step S2, the controller 60 determines whether or not the brake pedal 63 is depressed.
The determination is made based on the output signal of a brake pedal switch (not shown). Here, the brake pedal switch outputs an ON signal when the brake pedal 63 is depressed, and outputs an OFF signal when the brake pedal 63 is not depressed.

Assuming that the driver is now stepping on the brake pedal 63, an ON signal is output from the brake pedal switch. As a result, the controller 60 sets the determination result of step S2 to "YES" and proceeds to step S3. In step S3, the controller 60 controls the motor 33 for each of the electric brake devices 11 so as to generate a braking force on each wheel according to the operation amount of the brake pedal 63 detected by the brake operation amount detection sensor 64. After performing feedback control based on the rotational position data of the position detector 57, the process proceeds to step S4.

That is, in step S3, the controller 60 controls the motors 33 so that only the electric brake device 11 generates the required braking force in the rear two-wheel electric brake device 11, while the front two-wheel electric brake device. In the device 11, each motor 33 is controlled so that the electric brake device 11 generates a braking force that supplements a required braking force by a braking fluid pressure generated by the master cylinder 65.

When generating a braking force, the controller 60 uses the motor 33 to rotate the nut member 3 of the ball screw 34.
7 is rotated in the forward direction. Then, the screw member 40, the rotation of which is restricted by the locking portion 43, moves in the direction of the disk 13 to bring the inner pad 14 into contact with the disk 13, and the caliper 17 moves with respect to the carrier 12 by the reaction force thereof, and 53 will be moved in the direction of the disk 13,
In this way, the inner pad 14 and the outer pad 15 are finally formed by the screw member 40 and the claw portion 53.
3, the pads 14 and 15 come into contact with the disk 13 to generate a braking force.

In the electric brake device 11 in which the brake fluid pressure from the master cylinder 65 is introduced into the chamber 48, in addition to the above, the propulsive force of the brake fluid pressure is applied to the screw member via the hydraulic piston 47. It is transmitted to 40. Then, since the ball screw 34 has reversibility between the rotational motion and the linear motion, the screw member 40 is rotated by this propulsive force while the pad 14, 14,
15 is pressed against the disk 13 to generate a braking force.

On the other hand, when releasing the braking force from this state, the controller 60
Is rotated in the return direction opposite to the forward direction. Then, the screw member 40 whose rotation is restricted moves in a direction away from the disk 13, and as a result, the inner pad 14 and the outer pad 15 separate from the disk 13 to release the braking force. In the electric brake device 11 in which the brake fluid pressure from the master cylinder 65 is introduced into the chamber 48, the braking force is released together with the decrease in the brake fluid pressure.

In step S4, the controller 60
After resetting the timer, the process returns to step S2, and the above operation is repeated. Further, assuming that the brake pedal 63 has not been depressed, the controller 60 sets the determination result of step S2 to "NO" and proceeds to step S5. In step S5, the controller 60 determines whether or not an unillustrated accelerator pedal is depressed based on an output signal of an unillustrated accelerator pedal switch. Here, the accelerator pedal switch outputs an ON signal when the accelerator pedal is depressed, and outputs an OFF signal when the accelerator pedal is not depressed.

Now, assuming that the accelerator pedal is depressed, the controller 60 sets the determination result of step S5 to "YES" and proceeds to step S6. Step S6
Then, the controller 60 determines that the clearance between the disk 13 and the inner pad 14 (the outer pad 15) is as shown in FIG.
As shown in FIG.
After controlling the motor current supplied to the motor 33 while receiving the feedback signal from the
The above operation is repeated. Thereby, the inner pad 14 and the outer pad 15 are moved through the above-described operation, and as a result, the disc 13 and the inner pad 14 are moved.
Clearance between (outer pad 15) is 0.1m
m. That is, in this case, the disc 13 is completely out of contact with the inner pad 14 and the outer pad 15 (non-dragging state). As a result, the drag is reduced during the normal running, so that the fuel efficiency can be improved.

On the other hand, if the accelerator pedal is not depressed, in other words, the accelerator pedal is in the released state, the controller 60 sets the determination result of step S5 to "NO" and proceeds to step S7. Step S
At 7, the controller 60 determines whether or not the vehicle is running based on the output signal of a rotation sensor (not shown). The rotation sensor is a sensor that detects the rotation of the disk 13.

Now, assuming that the vehicle is stopped, the controller 60 determines "NO" in step S7 based on the output signal of the rotation sensor, and proceeds to step S8. In step S8, the controller 60 determines that the clearance between the disk 13 and the inner pad 14 (outer pad 15) is zero as shown in FIG.
After controlling the motor current to be supplied to the motor 33 while receiving the feedback signal from the position detector 57 so that the inner pad 3 and the inner pad 14 (the outer pad 15) slightly contact (overlap by 0.02 mm), it is not shown. The timer is reset, the process returns to step S2, and the above operation is repeated. Thereby, through the operation described above,
The inner pad 14 and the outer pad 15 are moved,
As a result, the clearance between the disk 13 and the inner pad 14 and the outer pad 15 is reduced to zero.
In the above description, zero pad clearance is
Disk 13 and inner pad 14 (outer pad 15)
And a slight contact (overlapping by 0.02 mm) is included. This is because an example is described in which zero pad clearance is detected based on a change in motor current to the motor 33. It goes without saying that the zero clearance of the pad may be only the state where the clearance, which does not include the overlap, is originally zero.

Accordingly, in this case, since the clearance is zero, it is possible to prevent dust and water from entering between the disk 13 and the inner pad 14 and the outer pad 15, and to prevent icing. be able to.
Therefore, in this case, the initial braking force at the start of the brake operation can be improved, and the initial response characteristics at the start of contact of the disc 13 with the inner pad 14 and the outer pad 15 can be improved.

On the other hand, if the vehicle is running,
The controller 60 determines “YES” in step S7 based on the output signal of the rotation sensor, and determines in step S10
Proceed to. In step S10, the state where the electric brake device is not used (the disc 13 and the inner pad 14) is not used.
It is determined whether or not the value of the timer for measuring the time in a state where the outer pad 15 is not in contact with the outer pad 15 is larger than a predetermined value T1. That is, it is determined whether or not the electric brake device is not in use for a time when it can be determined that it is necessary to perform the performance reduction prevention control described later. If the timer value is larger than the predetermined value T1 in step S10, the process proceeds to step S10.
8 is executed. In step S8, the controller 60
Are the disk 13 and the inner pad 14 (the outer pad 1
As shown in FIG. 4, the feedback signal from the position detector 57 is set so that the clearance between the disk 13 and the inner pad 14 and the outer pad 15 slightly contact (overlap by 0.02 mm). After controlling the motor current to be supplied to the motor 33 while receiving the timer value, the timer value is set to T2 (> T
It is determined whether 1) has elapsed. If T2 has elapsed, a timer (not shown) is reset in step S13, and the process returns to step S2 to repeat the above-described operation.
Accordingly, the inner pad 14 and the outer pad 15 are moved through the above-described operation, and as a result, the clearance between the disk 13 and the inner pad 14 and the outer pad 15 is zero, that is, the disk 13, the inner pad 14 and the outer pad 15 15 makes slight contact.

As described above, the clearance between the disc 13 and the inner pad 14 and the outer pad 15 is reduced, and the motor 33 is controlled so that the disc 13 and the inner pad 14 and the outer pad 15 slightly contact the disc 13. Performance reduction prevention control is performed. For this reason, the space between the disk 13 and the inner pad 14 and the outer pad 15 is temporarily dragged, and cleaning for removing dust and moisture between the disk 13 and the inner pad 14 and the outer pad 15 is performed. Become. Therefore, even when the electric brake device is not used for a long time during traveling, a decrease in pad performance can be prevented, and a reliable braking force can be exerted.

On the other hand, if the timer value is equal to or smaller than the predetermined value T1, the controller 60 determines that the result of the determination in step S10 is "NO" and proceeds to step S11. That is, wear of the inner pad 14 and the outer pad 15 due to the performance reduction prevention control being performed more frequently than necessary is prevented. In step S11, the controller 60 determines that the clearance between the disk 13 and the inner pad 14 (outer pad 15) is a small gap (0.05 m) shown in FIG.
After controlling the motor current to be supplied to the motor 33 while receiving the feedback signal from the position detector 57 so as to satisfy m), the process returns to step S2, and the above-described operation is repeated.

Accordingly, as shown in FIG. 5, the inner pad 14 (outer pad 15)
The clearance indicated by the position Z is moved from the minute gap position indicated by the position F to the position where the clearance indicated by the position Z is zero. In this movement, the inner pad 14 (the outer pad 15) is moved as shown in FIG.
Moves while showing smooth movement characteristics. The absolute value of the difference between the position F and the position Z shown in FIG.
mm. In this case, since the clearance is a small gap, even if the brake pedal is suddenly depressed, the inner pad 14 and the outer pad 15 come into contact with the disc 13 in a very short time, so that the initial response characteristics of the brake are improved. I do. Further, in this case, since the movement trajectory of the inner pad 14 and the outer pad 15 is smooth, the sound generated when the inner pad 14 and the outer pad 15 contact the disk 13 can be reduced.

According to the electric brake device described above,
When the accelerator pedal is turned off in step S5 and the vehicle is detected to be running in step S7, and when the time during which the electric brake device is not used elapses a predetermined time In addition, the clearance between the disc 13 and the inner pad 14 and the outer pad 15 is reduced, and the disc 13 and
Performance reduction prevention control for controlling the motor 33 so that the inner pad 14 and the outer pad 15 are slightly in contact with each other is performed. Therefore, the disc 13 is temporarily dragged between the inner pad 14 and the outer pad 15, and the disc 13 and the inner pad 14
The dust and moisture between the outer pad 15 and the outer pad 15 are removed. Therefore, the effect that the pad performance does not decrease even when the electric brake device is not used for a long time during traveling can be obtained.

In addition, only when the vehicle is running and the accelerator pedal is turned off, that is, when the driver has no intention to accelerate, performance reduction prevention control is performed. The driver does not feel uncomfortable when the lowering prevention control is performed. Therefore, the performance reduction prevention control can be performed without giving the driver a feeling of strangeness.

Although the electric brake device according to one embodiment of the present invention has been described in detail, the specific configuration is not limited to this one embodiment, and the specific configuration is within the scope of the present invention. Even a design change or the like is included in the present invention. For example, in the electric brake device according to the above-described embodiment, the displacement sensor 100 shown in FIGS. 6A and 6B is provided near the inner pad 14 and the inner pad 14 is determined based on the detection result of the displacement sensor 100. The clearance between the disc and the disc 13 may be determined, and the controller 60 may perform the clearance control based on the result.

FIG. 6A is a plan view showing the structure of the inner pad 14 and the displacement sensor 100, and FIG.
FIG. 2 is a side view showing the configuration of the inner pad 14 and the displacement sensor 100. The displacement sensor is an inner pad 1
4 is a sensor for detecting the amount of displacement in the axial direction, and is provided near the inner pad 14.

Further, in the electric brake device according to the above-described embodiment, referring to FIG. 4, specific values of the clearance (0.02 mm, 0.10 mm and 0.1 mm) are set.
05 mm), but each numerical value is an example, and the present invention is not limited to this. Accordingly, the values of the above clearances are appropriately determined based on various test data, and may be any values as long as the magnitude relation of each numerical value matches the magnitude relation of the specific numerical values shown in FIG. You may.

[0043]

As described above, according to the electric brake system of the present invention, when the operation of turning off the accelerator pedal is detected and the vehicle is detected to be running, the motor is driven by the pad and the disk. The clearance between the pad and the disk is controlled, and the motor is controlled so that the pad makes slight contact with the disk. Water will be removed. Therefore,
During traveling, the pad performance is not reduced even when the electric brake device is not used for a long time. Moreover, the pad and the disk are brought into contact only when the vehicle is running and the accelerator pedal is turned off, that is, when the driver has no intention to accelerate. The driver does not feel a sense of incongruity that occurs when the driver is brought into contact with the vehicle. Therefore, the pad can be brought into contact with the disk without giving the driver an uncomfortable feeling.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an electric brake device according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a brake system to which the electric brake device according to one embodiment of the present invention is applied.

FIG. 3 is a flowchart illustrating an operation of the electric brake device according to one embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a rotor-pad clearance and a motor current in the electric brake device according to one embodiment of the present invention.

FIG. 5 is a diagram showing pad positions in the electric brake device according to one embodiment of the present invention.

FIG. 6 shows a modification of the electric brake device according to one embodiment of the present invention.

[Explanation of symbols]

 13 Disc 14 Inner pad 15 Outer pad 33 Motor 34 Ball screw (conversion mechanism) 40 Screw member 57 Position detector (Position detecting means) 60 Controller (Control means)

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J058 AA43 AA48 AA53 AA63 AA69 AA73 AA78 AA87 BA26 BA27 BA73 CC15 CC17 CC77 DA03 DA32 DB18 DB23 DB29 DE16 FA01 FA11 FA21

Claims (1)

[Claims] 1. A motor, a conversion mechanism for converting a rotational motion of the motor into a linear motion of a piston, a position detecting means for detecting a stroke position of the piston, and the motor based on a detection result of the position detecting means. An electric brake device having control means for controlling a motor and generating a braking force by pressing a pad against a disk by linear movement of the piston, wherein travel detection means for detecting whether or not the vehicle is traveling; An accelerator pedal operation state detecting means for detecting an accelerator pedal off operation, wherein the control means detects the accelerator pedal off operation by the accelerator pedal operation state detection means, and the travel detection means If it is detected that the vehicle is running, the clearance between the pad and the disc is reduced, and the pad is moved forward. An electric brake device, wherein the motor is controlled so as to make slight contact with the disk.