JP2002205634A - Electric brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric brake device capable of preventing generation of a brake judder phenomenon at the time of braking by reducing adhesion amount to a brake rotating body of a brake friction material. SOLUTION: This electric brake device has a motor-driven means for pressing/separating the brake friction material for supporting the brake rotating body on a vehicle body side, an actuating state detection means for detecting an actuating state of the motor-driven means, a brake command generation means for fixing a brake command value according to brake manipulated variable, a brake control means for controlling driving amount of the motor-driven means to make the actuating state coincident with the brake command value and an adhesion detection means for detecting generation of adhesion of the brake friction material for the brake rotating body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric brake device used for braking a vehicle, and more particularly to an electric brake device for controlling a driver's brake operation amount and a running state of a vehicle without mechanically connecting a brake pedal and a brake caliper. Detected by a sensor,
Controlling the braking force by electronic control based on the detected signal,
The present invention relates to an electric brake device called a so-called brake-by-wire.

[0002]

2. Description of the Related Art Various types of brake devices are known as a brake-by-wire system.
In Japanese Patent No. 19740, in a braking device including a hydraulic brake caliper that generates a braking force by pressing a brake friction material (pad) with a hydraulic pressure (hydraulic pressure) on a rotor (rotating body of a brake), a hydraulic pressure ( A hydraulic brake-by-wire system that controls the braking force by arbitrarily changing the hydraulic pressure has been proposed.

[0003]

However, a brake device including the hydraulic brake device proposed in the above publication generally uses a brake friction material mixed with a resin.
After high-load braking, in other words, after the braking friction material becomes extremely hot, the resin eluted from the brake friction material due to the braking heat adheres to the surface of the brake rotating body and fluctuates in the thickness of the rotating body. This has the potential to cause brake judder during the next braking.

[0004] Further, when the adhesion occurs, the brake friction material adheres to the brake rotating body. If the adhesion can be detected, the occurrence of the adhesion can be detected. However, in the brake device proposed by the above publication, the brake friction material is separated from the brake rotating body by using the elasticity of the piston seal of the hydraulic brake caliper, and the separation operation is performed regardless of the presence or absence of the fixation. It is difficult to detect the sticking. Therefore, when the adhesion occurs, the occurrence of the adhesion cannot be immediately detected.

Further, the adhered matter adhered to the brake rotating body can be peeled off by a slight braking, that is, a braking operation similar to a brake drag. However, this small braking operation requires a high-precision low-pressure control. In this regard, the brake device proposed in the above publication requires the hydraulic pressure (hydraulic pressure) with a higher precision than required for normal braking force control in order to effectively separate and separate the adhered matter of the brake rotating body. Pressure control that enables the control of the pressure is required, and the system becomes complicated.

Accordingly, the first to ninth aspects of the present invention are to completely solve the above-mentioned problems. Specifically, the brake-by-wire system is electrically driven, Secondly, it is possible to detect the adhesion of the friction material to the brake rotator with high accuracy, and secondly, it is possible to advantageously perform the separation of the adhesion to the brake rotator without complicating the system. Thirdly, it is an object of the present invention to provide an electric brake device capable of reducing the amount of adhesion to a brake rotating body and thereby suppressing the occurrence of a brake judder phenomenon during braking.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a brake friction member which is supported on a vehicle body side of a vehicle is pressed against a brake rotating body which rotates together with wheels. An electric means for separating, an operation state detecting means for detecting an operation state of the electric means, a brake command generation means for determining a brake command value according to a brake operation amount of a driver, and the operation state to the brake command value. An electric brake device comprising: a brake control means for controlling a drive amount of an electric means to make them coincide with each other; and an adhesion detecting means for detecting occurrence of adhesion of a brake friction material to a brake rotating body.

According to the first aspect of the present invention, the electric means for pressing and separating the brake friction material, the operating state detecting means, the brake command generating means, and the brake control means for controlling the driving amount of the electric means are provided. The presence or absence of the occurrence of adhesion can be detected with high accuracy in combination with the adhesion detecting means for detecting the occurrence of adhesion of the brake friction material.

According to the invention described in claim 1, claim 2 is provided.
When the adhesion detecting means detects the occurrence of the adhesion of the brake friction material to the brake rotating body, the drive control of the electric means is performed in a direction in which the brake friction material is brought into contact with the brake rotating body. It has an adhesion removing means.

According to the second aspect of the present invention, in a certain braking operation, when adhesion is detected by the adhesion detecting means, the brake friction material is applied to the brake rotating body in an idle running state immediately after the vehicle is braked. By driving the electric means in the direction of contact, the brake drag is induced, the adhered matter of the brake rotating body is separated and separated by the brake drag, and the plate thickness of the brake rotating body can be uniformly maintained, so that the brake judder phenomenon Can be prevented from occurring.

According to the first aspect of the present invention, a third aspect is provided.
As described above, the road surface gradient detecting means for detecting the gradient of the traveling road surface, and the stop maintenance braking force calculation for calculating the braking force required for maintaining the vehicle stop based on the road surface gradient detected by the road surface gradient detecting means. Means, the adhesion detection means detects the occurrence of adhesion, and thereafter, when the command of the brake command value continues to each electric means of all the wheels of the vehicle, and the vehicle is stopped, Based on the braking force calculation result of the stop maintaining braking force calculating means, a wheel necessary for maintaining the vehicle stop and a wheel unnecessary for maintaining the stop are obtained, and the brake friction material is separated from a brake rotating body of the wheel unnecessary for maintaining the stop. In addition, there is an anti-adhesion means for controlling the driving of the electric means so as to alternate between the wheel required for maintaining the stop and the wheel unnecessary for maintaining the stop at predetermined time intervals.

According to the third aspect of the present invention, the brake according to the first aspect of the present invention is combined with the road surface gradient detecting means, the stop maintaining braking force calculating means, and the adhesion suppressing means. When the friction material continues to be pressed against the brake rotating body, the amount of adhesion continues to increase.By replacing the braking wheel and the non-braking wheel, the contact time between the brake friction material and the brake rotating body per wheel is reduced. It is possible to reduce the amount of adhesion of each of the four wheels in a state where the vehicle is stopped, and as a result, it is possible to uniformly maintain the thickness of the brake rotating body around the circumference, and The degree of the brake judder phenomenon during braking can be reduced.

According to the third aspect of the present invention, as in the fourth aspect of the present invention, there is provided an adhered substance removing means according to the second aspect. According to the invention as set forth in claim 4, the additional arrangement of the adhered substance peeling means allows the adhered substance to be peeled off and separated even if a small amount of adhered substance remains on the brake rotor.
Since the plate thickness of the brake rotor is made more uniform around the circumference, the occurrence of the brake judder phenomenon can be completely prevented.

According to the first and second aspects of the present invention, as in the fifth aspect of the present invention, the operating state detecting means detects any one of a rotational angular displacement and an axial displacement of the electric means. Displacement detecting means and current detecting means for detecting an operating current of the electric means are provided.

According to the fifth aspect of the present invention, since the displacement detecting means and the current detecting means have strong resistance to external noise, the displacement and the current of the electric means can be stably detected. However, the operating state of the electric means can be ensured with high reliability.

According to the first to third aspects of the present invention, when the brake friction material is separated from the brake rotating body by the electric means as in the invention described in the sixth aspect, the adhesion detecting means includes: It has a function of determining that adhesion has occurred when the detected current of the current detecting means included in the operating state detecting means is equal to or greater than a predetermined value in absolute value.

According to the present invention, the current detecting means of the operating state detecting means is used as the adhesion detecting means, and the current value when separating the brake friction material from the brake rotating body is equal to or more than a predetermined value. In this case, it is determined that adhesion has occurred, so that there is no need to add an extra measuring instrument, and the system can be simplified and a highly reliable brake device can be provided.

Further, apart from the invention described in claim 6,
According to the invention described in claims 1 to 3 and claim 5, as in the invention described in claim 7, the adhesion detecting means detects current when the brake friction material is pressed against the brake rotating body by the electric means. When the value obtained by dividing the detected current by the amount of displacement detected by the displacement detecting means is equal to or less than a predetermined value, it is determined that adhesion has occurred.

According to the seventh aspect of the present invention, the displacement detecting means and the current detecting means of the operating state detecting means are used as the adhesion detecting means, and the value of the current flowing through the electric means at the time of braking is simultaneously determined by the electric means. When the value divided by the displacement is less than the predetermined value, it is determined that adhesion has occurred.Therefore, there is no need to add an extra measuring instrument, and the system is simplified, and the adhesion detection accuracy is more reliable. A rich brake device can be provided.

According to the second or fourth aspect of the present invention, as in the eighth aspect of the present invention, the adhered matter separating means estimates the amount of adhesion of the brake friction material to the brake rotating body. Having an amount estimating means, and the adhered substance removing means,
It has a function of controlling the drive of the electric means in accordance with the amount of adhesion estimated by the amount of adhesion estimation means.

According to the eighth aspect of the present invention, since the adhesion amount estimating means is provided and the brake drag amount can be changed in accordance with the estimated adhesion amount, the adhesion amount can be reliably reduced. This makes it possible to shorten the brake drag time.

According to the invention described in claim 8, claim 9 is concerned.
The adhesion amount estimating means, based on the displacement amount detected by the displacement detecting means when the brake means is pressed against the brake rotating body by controlling the driving of the electric means with a constant current, as in the invention described in (1). It has a function of estimating the amount of landing.

According to the ninth aspect of the present invention, there is provided means for estimating the amount of adhesion based on the amount of displacement detected when the brake means is pressed by driving the electric means with a constant current. There is no need to newly add an adhesion amount measuring instrument, and an inexpensive brake device can be provided.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the examples shown in FIGS. FIG. 1 is a schematic diagram of an overall configuration showing a cross section of a main part of an electric brake device of the present invention. In FIG. 1, an electric brake device 1 includes a brake rotating body 2 that rotates with wheels (not shown), a brake rotor (hereinafter referred to as a rotor) 2 in the illustrated example, and a brake friction material 3 supported on a vehicle body (not shown). In the illustrated example, a brake pad (hereinafter referred to as a pad) 3 and a pad 3
And an electric means 4 for pressing the rotor 2 against the rotor 2 and separating the rotor 2 from the rotor 2. The pad 3 has a pair of inner pads 3-1 and outer pads 3-2 for pressing the rotor 2 from both sides.

The illustrated electric means 4 includes a motor 6 mounted and fixed inside an electric caliper (hereinafter referred to as a caliper) 5,
It has a male screw 8 of a ball screw provided at the tip of a rotating shaft 7 of the motor 6, and a nut 9 of a ball screw screwed to the male screw 8. The nut 9 is fixed to a piston 12 having a guide member 11 slidably fitted in a groove 10 in the direction of the rotating shaft 7 provided on the inner surface side of the caliper 5. 9 is movable in the axial direction of the rotating shaft 7 and restrains the turning of the rotating shaft 7 in the rotating direction. The illustrated motor 6 is a servo motor, and the other motors 6
Alternatively, a linear motor can be applied. In the latter case,
No ball screw is required, and the shaft of the linear motor is directly connected to the piston 12. Hereinafter, a case where a servomotor is mainly used will be described.

The inner pad 3-1 is fixed to the tip of the piston 12, and the outer pad 3-2 is fixed to the inside of the caliper 5 at a position facing the pad 3-1 which sandwiches the rotor 2. Only advance and retreat is allowed without rotating. When the electric brake device 1 is not operated, the pair of pads 3-1 and 3-2 are positioned with a predetermined clearance c between the pads 3-1 and 3-2.

When the electric brake device 1 is in operation, the motor 6 of the electric means 4 is operated, the male screw 8 of the ball screw for converting the rotational motion into a linear motion is rotated (forward rotation), and the nut 9 is moved together with the piston 12 into the motor. 6 in the direction of the axis, thereby pressing the pad 3-1 against the inner surface of the rotor 2,
The caliper 5 is moved in a direction opposite to the above moving direction by a reaction force from the rotor 2 due to this pressing, and the pad 3-2 is pressed against the outer surface of the rotor 2 to generate a braking force. To release the brake, rotate the male screw 8 in the reverse direction and move the pad 3-1 and 3-2 in the reverse direction.
Is separated from the rotor 2.

The electric brake device 1 includes a brake pedal 14
A brake command value generating means 15 connected to the
Has a pedaling force sensor 16 for detecting a pedaling force as a driver's operation amount of the brake pedal 14 and a stroke sensor 17 for detecting a stepping amount, and determines a brake command value based on the outputs of these sensors 16 and 17. The value is transmitted to the brake control means 18 as a signal. The brake control means 18 outputs an output of a current sensor 19 as a current detecting means for detecting an operation current of the electric means 4 so that a brake command value and an operation state of the electric means 4, here, a rotation angle of the motor 6 coincide. The power supply unit 20 is controlled on the basis of the above, the output power from the power supply unit 20 is supplied to the motor 6, and the motor 6 is rotated.

That is, the electric brake device 1 has operating state detecting means for detecting the operating state of the electric means 4, and the means in the illustrated example is a rotation angle sensor 21 attached to the rotating shaft of the motor 6, and the brake control Means 18 and rotation angle sensor 21
And are connected by a circuit. The brake control means 18 controls the pad 3
-1, 3-2 are pressed and the output of the rotation angle sensor 21 at the time of starting contact with the rotor 2 is set as a reference value, and the brake command value and the output from the rotation angle sensor 21 from the reference value, that is, the motor The braking force is controlled by controlling the output of the power supply unit 20 so that the detected value of the rotation angle coincides with the value of the rotation angle. The operating state detecting means detects a pressing force sensor for detecting the pressing force of the pads 3-1 and 3-2, or detects a braking torque generated by rotation of the rotor 2 by the pressed pads 3-1 and 3-2. To be added. When a linear motor is applied to the motor 6, the operating state detecting means detects an axial displacement.

Here, the electric brake device 1 includes a rotor 2
And adhesion detecting means for detecting the occurrence of adhesion of the pads 3-1 and 3-2 to the pad. The details of the adhesion detecting means will be described later, and the adhesion will be described first. FIG. 2 shows a front view of the rotor 2 and the pad 3, and FIG.
FIG. 3 is an explanatory diagram of a plate thickness variation. FIG. 3 shows that significant adhesion occurs at locations where the pad 3 separates from the rotor 2 during heavy load braking. As described above, this adhesion is so-called temperature adhesion in which the resin eluted from the pad 3 due to the braking heat is welded to the rotor 2, and the adhesion between the temperature of the pad 3 immediately after the braking and the plate thickness variation of the rotor 2 is obtained. From FIG. 4 showing the relationship in a diagram, it can be seen that the higher the temperature of the pad 3, the larger the amount of adhesion of the part where the pad 3 is separated from the rotor 2, and the larger the thickness variation (micrometer, μm).

When the adhesion detecting means detects the adhesion of the pad 3 to the rotor 2, the electric brake device 1 controls the electric means 4 to drive the electric means 4 in the direction of bringing the pad 3 into contact with the rotor 2. It has peeling means. Hereinafter, first, the adhesion detection will be described with reference to the flowchart at the time of braking shown in FIG. 5 and the flowchart at the time of idle running shown in FIG.

That is, in FIG. 5, the driver depresses the brake pedal 14 during braking, so that the brake command value generating means 15 attached to the brake pedal 14 uses the sensor 16 and the sensor 17 to depress the pedaling force and the stepping amount ( Stroke (ST) as a brake (B) pedal operation amount (ST
EP101), the brake control means 18 generates a braking force by driving the motor 6 of the electric means 4 (STEP 102) so that the brake command value and the operation amount of the electric means 4 have a predetermined relationship. ST while the brake pedal 14 continues to be depressed
Repeat EP101 and EP102.

On the other hand, when the depression of the brake pedal is released (STEP 103), the current Is of the motor 6 at the moment when the pad 3 separates from the rotor 2 is read in order to judge whether or not adhesion has occurred (to be described later in detail) (STEP 104). If the current Is is equal to or greater than the predetermined value A in absolute value, it is determined that adhesion has occurred (STEP 105), and the adhesion occurrence flag g is set to 1 (STEP 106).
If the absolute value of the current Is is less than the predetermined value A in STEP 105, it is determined that no adhesion has occurred, and the adhesion occurrence flag g is set to zero (0) (STEP 107).

In FIG. 6, during non-braking, that is, during idling, first, the operation amount of the brake pedal 14 is read (STEP
108) and determine whether the driver intends to brake (STEP
109) When the brake pedal 14 is depressed, the above-described braking routine is performed. When the brake pedal 14 is not operated, the adhesion is determined (STEP 110). Is executed (STEP 111).

Here, the adhesion detecting means will be described in detail based on the diagram of the rotation angle of the motor 6 and the current of the motor 6 shown in FIG. FIG. 7 shows the left side at the time of braking, the right side after braking, and shows the moment when the pad 3 separates from the rotor 2 at the center position. In FIG. 7, a comparison of the elapsed time transition between the current of the motor 6 and the rotation angle of the motor 6 before and after the separation of the pad 3 and the rotor 2 between when the adhesion is not generated and when the adhesion is generated, shows that immediately after the separation. The rotation angle of the motor 6 is substantially the same irrespective of the occurrence of adhesion, whereas the current of the motor 6 has a remarkable overshoot when adhesion occurs. This means that when the eluted material of the pad 3 adheres to the rotor 2, the eluted resin acts like an adhesive, and a large force, that is, the torque of the motor 6 is required to peel the pad 3 from the rotor 2. This is because

Therefore, in the electric brake device 1,
When the pad 3 is separated from the rotor 2 by the electric means 4, the function of judging that adhesion has occurred when the detection current of the current sensor 19 as the current detection means provided in the operating state detection means is equal to or less than a predetermined value. And

Next, the peeling of the adhered matter will be described with reference to the sliding torque (× 9.8 × 10 ⁻² Nm) and the relationship between the amount of adhesion (μm) and the sliding time (sec) shown in FIG. FIG. 8 shows a state in which the electric means 4 is brake-driven and the pad 3 is slightly pressed against the rotor 2 on which the adhesion has occurred to cause the rotor 2 to slide.
The position of the pad 3 is set to 10 μm, 15 μm, and 20 μm from the contact position between the rotor 2 and the pad 3 toward the rotor 2.
m, and represents the relationship between the drag torque and the amount of adhesion when the brake is dragged while maintaining the pushed amount. From FIG. 8, it can be seen that the amount of adhesion can be reduced by pushing the pad 3 into the rotor 2 to generate a drag torque, and that the greater the amount of pad 3 pushed, the more the amount of adhesion can be reduced within a shorter drag time. It can be seen that it can be reduced. Therefore, the adhered substance separating means is realized by controlling the driving of the electric means 4 in the direction in which the pad 3 is brought into contact with the rotor 2.

The electric brake device 1 shown in FIG.
Road surface gradient detecting means for detecting the gradient of the traveling road surface, based on the road surface gradient detected by the road surface gradient detecting means, a stop maintaining braking force calculating means for calculating a braking force required to maintain the stop of the vehicle,
And adhesion preventing means. The adhesion preventing means is such that the adhesion detecting means detects the occurrence of adhesion of the rotor 2, and thereafter, the brake command value is continuously supplied to each of the electric means 4 of all the wheels of the vehicle to stop the vehicle. At this time, the wheels required for maintaining the vehicle stop and the wheels unnecessary for maintaining the stop are determined based on the braking force calculation result of the stop maintaining braking force calculating means, and the pad 3 is separated from the rotor 2 of the wheel not required for maintaining the stop. At the same time, the driving means controls the electric means 4 at predetermined time intervals so that wheels required for maintaining the stop and wheels unnecessary for maintaining the stop are alternated.

This will be described with reference to the flowchart shown in FIG. In FIG. 9, at the time of braking, the operation amount of the brake pedal 14 is read in accordance with
201), the drive of the motor 6 is controlled so that the operation amount of the brake pedal 14 and the braking force have a predetermined relationship (STEP 203). As will be described in detail later, the motor 6 current I
s and the motor rotation angle X are read (STEP 204), and the value of the ratio Is / X of the current Is to the angle X is determined (STEP 20).
5) If the value of the ratio Is / X is less than a predetermined value, it is determined that adhesion has occurred. When the value of the ratio Is / X is equal to or less than a predetermined value, the function of judging that adhesion has occurred is defined as second adhesion detection means different from the above.

When the adhesion detecting means detects the occurrence of adhesion, the adhesion occurrence flag g2 is set to 1 (STEP 206). On the other hand, if the adhesion detecting means does not detect the occurrence of adhesion, the adhesion occurrence flag g2 is set to zero (0) (STEP 207).
While the brake pedal 14 is being operated, the above STEP is repeated, and the operation of the brake pedal 14 is released to terminate the braking (STEP 208).

When the contact between the rotor 2 and the pad 3 is continued under the condition that the adhesion detecting means detects the occurrence of the adhesion, in other words, when the brake pedal 14 is continuously depressed with the vehicle completely stopped, the adhesion is stopped. Since the adhesion continues to progress and the amount of adhesion becomes remarkable, when it is estimated that adhesion occurs (STEP 209) with the vehicle stopped (STEP 202), the following control is performed.

That is, first, the gradient of the road surface at which the vehicle is stopped is detected by the road surface gradient detecting means, and is read (STEP 210). Calculates the stop maintenance braking force necessary to hold the stop (STEP 211).

For example, in a vehicle having four wheels and having the respective electric brake devices 1 provided on the respective wheels, the two electric brake devices 1 disposed diagonally are provided with the calculated stop maintaining braking force.
If it is within the range of control force that can be generated at (STEP 212), first, the elapsed time t from the stop time is counted, and the process proceeds to STEP 214 until it reaches a predetermined value T2 (STEP 213).
Next, if the elapsed time t is less than the predetermined value T1, the process proceeds to STEP215. In STEP 215, a vehicle stop maintaining braking force is generated between the left front wheel and the right rear wheel to release the braking of the remaining right front wheel and left rear wheel, that is, the pad 3 is separated from the rotor 2 (STEP 215).

When the elapsed time t becomes equal to or greater than the predetermined value T1 (STEP 214), the above-described brake wheels and brake release wheels are alternated (STEP 216), and the rotors of the respective wheels are rotated within the stop time of the vehicle. By shortening the contact time with each pad 3, the amount of adhesion of each pad 3 can be greatly reduced.

When the elapsed time t has reached the predetermined value T2 (STEP 213), the elapsed time t is reset once (STEP 21).
7) By executing the routine, the above-mentioned brake wheel and the brake release wheel are replaced again. Note that, here, an example in which two electric brake devices 1 arranged diagonally are controlled in the same manner has been described.
The generation and release of the braking force may alternate between the front two wheels and the rear two wheels. In addition, although the description has been given of the braking / non-braking sharing of two wheels, if the stop of the wheels can be maintained, one braking wheel may be used. Further, it is preferable to add an adhered substance peeling unit, which will be described in detail later, to the electric brake device 1 having the road surface gradient detecting unit, the stop maintaining braking force calculating unit, and the adhesion suppressing unit.

FIG. 7 shows the second adhesion detecting means again.
This will be additionally described using FIG. The left side of FIG. 7 shows a time transition between the motor 6 current during braking and the rotation angle position of the motor 6,
The current and the rotation angle of the motor 6 show the case with adhesion and the case without adhesion, respectively. The current of the motor 6 is substantially proportional to the torque of the motor 6, and the caliper 5 has a certain rigidity in which the rigidity of the pad 3 is dominant. Therefore, the motor 6 current Is, the motor 6 rotation angle X, and the rigidity k of the caliper 5 have a relationship represented by the formula (Is / X) = Ck. Here, the symbol C is a proportional constant.

Therefore, the rigidity k of the caliper 5 can be estimated by actually measuring the value of the ratio Is / X. Here, as can be seen from FIG. 7, when adhesion occurs to the rotor 2, the value of the motor rotation angle X increases. That is, since the temperature of the pad 3 becomes high and the rigidity of the pad 3 decreases,
The rigidity k of the caliper 5, that is, the value of the ratio Is / X is reduced. Therefore, when the value of the ratio Is / X is equal to or less than the predetermined value B, it can be determined that adhesion has occurred. .

The adhered substance peeling means of the electric brake device 1 has an adhesion amount estimating means. Hereinafter, the adhesion amount estimating means will be described with reference to a flowchart shown in FIG. That is, when the adhesion of the rotor 2 is detected by the adhesion detection means described above and the brake is dragged, first, the drive of the motor 6 with the built-in caliper 5 is controlled by a current, and at a constant current Io, , Pad 3 with constant axial force
(STEP301). Driving the motor 6 with a constant current is based on the motor 6 current Is and the motor 6
The rotation angle X and the rigidity k of the caliper 5 are given by (Is / X) =
Since the current Io is constant, the motor 6
By detecting the rotation angle, the thickness of the rotor 2 sandwiched between the pair of pads 3-1 and 3-2 can be measured.

Next, at the same time as reading the rotor angle using a wheel speed pulse used for ABS or the like (STEP 302), the position of the motor 6 corresponding to the thickness of the rotor 2 is read (STEP 30).
3). When the brake pedal 14 is operated in the brake dragging process, the operation immediately shifts to normal braking in which the brake pedal operation amount and the position of the motor 6 have a predetermined relationship (ST
EP304, 305). When the detection of the rotation angle of the motor 6 for one rotation of the rotor 2 is completed, the rotation of the rotor 2 for one rotation of the rotor 2 is completed.
The sheet thickness is recorded (STEP 306), compared with the rotor 2 sheet thickness of one rotation of the rotor 2 when the adhesion and peeling is completed by the previous sliding (STEP 307), and the amount of adhesion is calculated (STEP 308).

Here, FIG. 11 shows a comparison diagram of the rotation angle output of the motor 6 when adhesion is occurring and when adhesion is not occurring. In FIG. 11, in STEP 307, the thickness of the rotor 2 in the routine is changed to the rotor 2 thickness after the previous drag.
In comparison with the plate thickness, the change in the plate thickness due to the wear of the rotor 2 due to normal braking is significantly smaller than the amount of adhesion, so that the detection of the amount of adhesion has sufficient accuracy. Further, regarding the resolution of the plate thickness detection of the rotor 2, the system used by the inventors for the experiment uses an encoder of 1024 pulses per rotation of the motor 6, and provides an overall lead, that is, the motor 6.
The stroke of the piston 12 per rotation is 2.5 mm / 1
Because of the rotation, the resolution of the rotor 2 plate thickness is 2 μm, which is sufficient resolution to suppress the brake judder phenomenon that occurs when the amount of adhesion is more than tens of μm.

Returning to the flowchart shown in FIG. 10, it is determined whether the calculated amount of adhesion is equal to or more than the predetermined value C or less than the predetermined value C (STEP 309), and the relationship between the drag current of the motor 6 and the amount of adhesion is represented by a line. Referring to FIG. 12 shown in the drawing, when the adhesion amount is equal to or more than the predetermined value C, the current of the motor 6 at the time of sliding is changed according to the adhesion amount (STEP 310). This is because if the amount of adhesion exceeds a predetermined value C, judder is generated. If the adhesion amount is less than the predetermined value C, brake dragging is prohibited and unnecessary consumption of fuel is prevented. Also, usually, the brake interval, that is, the idle running time,
According to the experiments performed by the inventors, it is about 40 seconds. Therefore, by setting the minimum amount of brake drag to separate the adhered substances within this idle running time, unnecessary consumption of fuel is prevented as described above.

As described above, the amount of drag is changed in accordance with the amount of adhesion, and the separation of the adhered material is completed. When the amount of adhesion becomes less than the predetermined value C, the motor for one rotation is recorded (STEP 311). At the same time, a predetermined clearance c is secured between the rotor 2 and the pad 3 so that the drag is released in preparation for normal braking (STEP
312), the adhesion occurrence flag g is reset (STEP 313).

Summarizing what has been described with reference to FIGS. 10 to 12, the adhered substance peeling means has a function of controlling the drive of the electric means 4 in accordance with the amount of adhesion estimated by the adhesion amount estimating means.
The adhesion amount estimating means has a function of estimating the adhesion amount based on the amount of displacement detected by the displacement detecting means when the pad is pressed against the rotor 2 by controlling the driving of the electric means 4 with the constant current Io. ,That's what it means.

[0054]

According to the first to ninth aspects of the present invention, a part of the brake friction material (pad) adhered to the brake rotating body (rotor) can be peeled off by brake sliding. In addition, when the contact between the brake rotor and the brake friction material continues, the amount of adhesion increases.However, the braking time and the non-braking wheel are alternated to reduce the contact time per wheel and maintain vehicle stopping. In this state, the amount of adhesion of each of the four wheels can be reduced, all of which can suppress the fluctuation of the thickness of the brake rotating body and effectively prevent the occurrence of brake judder at the next braking A braking device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an overall configuration showing a cross section of a main part of an electric brake device of the present invention.

FIG. 2 is a front view of a rotor and pads of the electric brake device shown in FIG.

FIG. 3 is an explanatory diagram of a thickness variation of a rotor on which adhesion has occurred.

FIG. 4 is a diagram showing a relationship between a pad temperature immediately after braking and a rotor plate thickness variation amount.

FIG. 5 is a flowchart illustrating an operation of the electric brake device shown in FIG. 1 during braking.

FIG. 6 is a flowchart illustrating an operation of the electric brake device shown in FIG. 1 during idling.

FIG. 7 is a graph showing changes in the motor rotation angle and the motor current during the period from braking to non-braking with and without adhesion.

FIG. 8 is a relationship diagram between the drag torque and the amount of adhesion of the electric brake device shown in FIG. 1 and the drag time.

FIG. 9 is a flowchart illustrating an operation of the electric brake device shown in FIG. 1 during braking and during adhesion prevention.

10 is a flowchart illustrating the operation of the electric brake device shown in FIG. 1 when the brake is dragged.

11 is a comparison diagram of a rotation angle output of a motor with and without occurrence of adhesion in the electric brake device shown in FIG. 1;

FIG. 12 is a diagram showing a relationship between a drag current of a motor and an amount of adhesion in the electric brake device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric brake device 2 Rotor 3 Pad 4 Electric means 5 Caliper 6 Motor 7 Rotating shaft 8 Male screw of ball screw 9 Nut of ball screw 10 Groove 11 Guide member 12 Piston 14 Brake pedal 15 Brake command value generating means 16 Treading force sensor 17 Stroke Sensor 18 Brake control means 19 Current sensor 20 Power supply 21 Rotation angle sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (9)

[Claims] 1. An electric means for pressing / separating a brake friction material supported on a vehicle body side of a vehicle with respect to a brake rotating body which rotates with wheels, an operating state detecting means for detecting an operating state of the electric means, a driver Brake command generating means for determining a brake command value in accordance with the amount of brake operation of the brake, brake control means for controlling a drive amount of an electric means to match the operation state with the brake command value, and a brake friction material for a brake rotating body And an adhesion detecting means for detecting the occurrence of adhesion of the electric brake. 2. The method according to claim 1, wherein when the adhesion detecting means detects the adhesion of the brake friction material to the brake rotating body, the adhered substance peeling control drives the electric means in a direction of bringing the brake friction material into contact with the brake rotating body. The electric brake device according to claim 1, further comprising a unit. 3. A road gradient detecting means for detecting a gradient of a traveling road surface, and a stop maintaining braking force calculating means for calculating a braking force required for maintaining the vehicle stop based on the road gradient detected by the road gradient detecting means. When the adhesion detecting means detects the occurrence of adhesion, and thereafter, the brake command value is continuously supplied to each of the electric means of all the wheels of the vehicle and the vehicle is brought to a stop state, a stop maintaining system is provided. On the basis of the braking force calculation result of the power calculation means, a wheel required for maintaining the stop of the vehicle and a wheel unnecessary for maintaining the stop are obtained, and a brake friction material is separated from a brake rotating body of the wheel unnecessary for maintaining the stop, and a predetermined value is determined. 2. The electric brake device according to claim 1, further comprising: adhesion preventing means for controlling driving of the electric means so as to alternate between a wheel required for maintaining the stop and a wheel unnecessary for maintaining the stop at time intervals. 4. The electric brake device according to claim 3, further comprising the adhered matter peeling means according to claim 2. 5. The operating state detecting means includes a displacement detecting means for detecting one of a rotational angular displacement and an axial displacement of the electric means, and a current detecting means for detecting an operating current of the electric means. The electric brake device according to claim 1 or 2, wherein: 6. The adhesion detecting means, when the brake friction material is separated from the brake rotating body by the electric means, when the current detected by the current detecting means provided in the operating state detecting means is equal to or greater than a predetermined value in absolute value. The electric brake device according to any one of claims 1 to 3, further comprising a function of determining occurrence of the electric brake. 7. The adhesion detecting means, when pressing the brake friction material against the brake rotating body by the electric means, when a value obtained by dividing a detection current of the current detection means by a detection amount of the displacement detection means is equal to or less than a predetermined value. The electric brake device according to any one of claims 1 to 3, further comprising a function of determining that adhesion has occurred. 8. The adhered matter removing means has a adhered amount estimating means for estimating the adhered amount of the brake friction material to the brake rotating body, and the adhered matter removing means is an adhesive based on the adhered amount estimating means. The electric brake device according to claim 2 or 4, wherein the electric brake device has a function of controlling driving of the electric means in accordance with the estimated amount of arrival. 9. The adhesion amount estimating means calculates the adhesion amount based on the displacement amount detected by the displacement detecting means when the electric motor is driven and controlled by a constant current to press the brake friction member against the brake rotating body. The electric brake device according to claim 8, having a function of estimating.