JP2003182546A - Electric brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control braking with high accuracy even when uneven wear occurs in a brake friction member in a vehicle controlling braking by detecting a pressing force of the brake friction member for a rotary body rotating together with wheels. <P>SOLUTION: A braking control amount for an electric motor is calculated and outputted (step S7 and step S8) so that braking torque calculated based on a pressing force detected by a pressing force sensor, bending moment detected by a bending moment sensor, the friction coefficient of a disc rotor and the brake friction member stored in advance, a bending moment measuring position from a shaft core of the disc rotor, and flexural rigidity of a caliper (step S6) coincides with target braking torque calculated in accordance with a brake operation amount (step S5). <P>COPYRIGHT: (C)2003,JPO

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 equipped with an electric drive mechanism such as an electric motor.

[0002]

2. Description of the Related Art In recent years, in addition to a hydraulic brake device using a working fluid, an electric motor is driven and rotated according to the amount of depression of a brake pedal, and a braking torque is generated by using the rotational force of the electric motor. Development of an electric brake device is in progress. As such an electric brake device, for example, the one described in Japanese Patent Laid-Open No. 9-137841 has been proposed.

The electric brake device described in this publication detects an electric actuator for moving a friction pad forward and backward toward a disk rotor rotating with a wheel, and an urging force acting on the friction pad from the actuator. A thrust sensor, a position sensor that detects the position of the friction pad, and a control unit that controls the operation of the actuator based on the operation status of a brake operating unit are provided, and the control unit includes a thrust sensor A thrust control function for controlling the operation of the actuator based on the detection signal and a position control function for controlling the operation of the actuator based on the detection signal of the position sensor are provided.

[0004]

However, in the electric brake device in the above-mentioned conventional example, as shown in FIG. 12 (a), when braking is repeated and uneven wear occurs on the friction pad, the contact surface of the friction pad is removed. Since it cannot be pressed parallel to the contact surface of the disk rotor, the center of the pressing force distribution deviates from the center of the friction pad or the effective radius of the disk rotor.

At this time, the braking torque T generated on the wheels
12B, the reaction force F generated by the thrust of the friction pad on the disc rotor, the friction coefficient μ between the disc rotor and the friction pad, and the axial center of the disc rotor on the inner pad side are The thrust distribution center position R _IN and the thrust distribution center position R _OUT from the axial center on the outer pad side can be used to represent the following formula (1). T = (μ ・ F ・ R _IN ) + (μ ・ F ・ R _OUT ) = μ ・ F ・ (R _IN + R _OUT ) ... (1) That is, the thrust detected by the thrust sensor Even if F is constant, the braking torque T changes because the thrust center position R of the friction pad with respect to the disk rotor fluctuates due to uneven wear of the friction pad. Furthermore, since the amount of uneven wear of the friction pad is different for each wheel,
There is an unsolved problem that the braking balance of the four wheels changes.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example. In a vehicle in which braking force is detected by detecting a pressing force of a brake friction material against a rotating body rotating together with a wheel, friction is reduced. An object of the present invention is to provide an electric brake device that enables highly accurate braking control even when uneven wear occurs on a pad and that can maintain a good braking balance of four wheels.

[0007]

In order to achieve the above object, an electric brake device according to claim 1 of the present invention comprises a brake operation amount detecting means for detecting an operation amount of a brake operating means by a driver, and a wheel. A holding portion that spans and holds a brake friction material with respect to a rotating body that rotates with it, an electric drive mechanism that controls the pressing force of the brake friction material with respect to the rotating body, and the brake operation amount detection means detect In an electric brake device comprising: a braking control unit that controls a braking control amount for the electric drive mechanism based on a brake operation amount, a pressing force detection unit that detects a pressing force of the brake friction material, and the holding unit. Bending moment detecting means for detecting the bending moment of the rotating body in the radial direction, and the pressing force and the bending moment detected by the pressing force detecting means. Braking torque calculating means for calculating a braking torque generated on the wheel based on the bending moment detected by the outputting means, and the braking torque calculated by the braking torque calculating means by the braking control means and the brake operation amount detecting means. It is characterized in that the braking drive amount for the electric drive mechanism is calculated and output so that the brake operation amount detected in step 1 has a predetermined relationship.

In the electric brake device according to a second aspect of the present invention, in the invention according to the first aspect, the two means, the pressing force detecting means and the bending moment detecting means, are portions that straddle the rotating body of the holding portion. It is characterized in that a common measuring means is provided for the two means for measuring any one of strain, stress and displacement of the outer peripheral portion and the inner peripheral portion. Further, the electric brake device according to a third aspect is the invention according to the first or second aspect, further comprising a friction material position detecting means for detecting a position of the brake friction material, wherein the pressing force detecting means is the friction material. The pressing force is detected based on the position of the brake friction material detected by the position detecting means and the rigidity indicating the relationship between the position of the brake friction material and the pressing force.

[0009]

According to the electric brake device of the first aspect of the present invention, the bending moment in the radial direction of the rotating body and the brake friction with respect to the rotating body in the holding portion that holds the brake friction material provided over the rotating body. Since the braking drive amount for the electric drive mechanism is calculated and output so that the braking torque detected based on the pressing force of the material and the brake operation amount have a predetermined relationship, the braking torque acting on the vehicle is set as the pressing force. Brake control can be performed with a value closer to the braking force that actually acts on the vehicle, as compared with the case of performing the control based on the control, and the braking control can be performed with high precision and the braking balance of the four wheels can be maintained well. The effect is obtained.

According to the electric brake device of the second aspect, the two means, the pressing force detecting means and the bending moment detecting means, are strains in the outer peripheral portion and the inner peripheral portion of the holding portion,
Since the two means for measuring the stress or the displacement are provided with the common measuring means, the pressing force can be reliably detected without providing the pressing force sensor, and the bending moment detection accuracy can be improved. The effect of being able to be obtained is obtained.

Further, according to the third aspect of the present invention, there is provided the friction material position detecting means for detecting the position of the brake friction material, and the pressing force detecting means detects the friction material position detecting means. Since the pressing force is detected based on the brake friction material position and the rigidity indicating the relationship between the brake friction material position and the pressing force, it is not necessary to provide a pressing force sensor, and the pressing force can be reliably and inexpensively provided. The effect that the pressure can be detected is obtained.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention, in which 1FL, 1FR, 1R are shown.
L and 1RR are electric brakes that generate braking torque for the front left wheel, the front right wheel, the rear left wheel, and the rear right wheel, respectively.

As shown in FIG. 2, each of the electric brakes 1FL to 1RR has a disk rotor 2 formed integrally with each wheel and a floating caliper 3FL to 3FL to apply a braking torque to the disk rotor 2. Three
And RR. These calipers 3FL to 3RR are
A base portion 6 in which an electric drive mechanism 5 for controlling the pressing force by advancing and retracting the inner pad 4b constituting the brake friction member 4 extending over the disk rotor 2 and controlling the pressing force is provided, and the disk rotor 2 And the bridge portion 7 that holds the outer pad 4a facing the inner pad 4b with the fixed state. The bridge portion 7 is provided with bending moment sensors 8FL to 8RR for detecting the bending moment of the disk rotor 2 in the radial direction (direction A in FIG. 2). The bending moment sensors 8FL to 8RR have strains. Gauges, stress sensors, displacement sensors, etc. are used.

Here, the electric drive mechanism 5 is provided with an electric motor 9 composed of a stepping motor as an electric rotary drive source, and a linear conversion mechanism 10 for converting rotational movement of the electric motor 9 into linear movement. There is. The linear conversion mechanism 10 includes a ball screw shaft 11 connected to a rotating shaft 9a of an electric motor 9, a ball nut 13 screwed onto the ball screw shaft 11 via a ball 12, and the ball nut 1.
3 and the engaging portion 14 which allows the sliding of the sliding member 3 and prevents the rotation thereof.

A rotary encoder 15 for detecting the rotation angle and the rotation direction of the electric motor 9 is attached. Further, the ball nut 13 is formed into a cylindrical shape in which the electric motor 9 side is opened and the side opposite to the electric motor 9 side is closed by an end plate 16, and between the end plate 16 and the inner pad 4b. Pressing force sensors 17FL to 17RR for detecting the pressing force applied to the disk rotor 2 are provided. Piezoresistive elements, strain gauge type load cells, strain gauges and the like are used for the pressing force sensors 17FL to 17RR. Further, in the engaging portion 14, the cross section of the outer peripheral surface of the ball nut 13 is formed into a polygonal shape such as a triangle or a quadrangle, and the inner peripheral wall of the caliper 3 is also formed into a polygonal shape in accordance therewith, or both are engaged. The ball nut 13 is prevented from rotating using a rotation preventing member such as a key.

The electric motor 9 of the electric drive mechanism 5 in the electric brake 1 is controlled by the control device 18 as shown in FIG.
Is controlled by. The control device 18 includes a wheel speed sensor 19 that detects a rotation speed of each wheel on which the disc rotor 2 is mounted, a longitudinal acceleration sensor 20 that detects a longitudinal acceleration that occurs in the vehicle, and a yaw rate sensor 21 that detects a yaw rate that occurs in the vehicle. And a brake operation amount sensor 24 for detecting the depression amount of a brake pedal 23 having a reaction force generation device 22 for generating a pseudo reaction force with respect to a driver's brake operation.

Each detection signal detected by these various sensors 19 to 21 and 24 and each electric brake 1FL to 1RR.
Angle and direction of rotation of the electric motor 9 detected by the rotary encoder 15 in FIG.
The bending moment signal detected by L to 8RR and the pressing force signal detected by the pressing force sensors 17FL to 17RR are, for example, a controller 25 configured by a microcomputer.
3, the controller 25 executes the braking control processing procedure of FIG. 3, which will be described later, calculates the braking torque required for each of the electric brakes 1FL to 1RR based on each input signal, and outputs the braking torque command value. To do.

The braking torque command values for the front left and rear left electric brakes 1FL and 1RR output from the controller 25 are input to a drive circuit 26A, and the drive circuit 26A outputs electric brakes 1FL and 1FL based on the braking torque command values. The braking torque command values for the front right and rear left electric brakes 1FR and 1RL that control the 1RR electric motor 9 and are output from the controller 25 are input to the drive circuit 26B. The electric motor 9 of the electric brakes 1FL and 1RR is controlled based on

It should be noted that the drive circuits 26A and 26B are individually supplied with power from the batteries 27A and 27B, and even when one of the batteries 27A and 27B, for example, the battery 27A has an abnormality and the output power is reduced. ,
Normal electric power can be supplied to the drive circuit 26B by the other battery 27B, and a necessary minimum braking torque can be secured.

Next, the operation of the above-described first embodiment will be described with reference to the flowchart showing the braking control processing procedure of FIG. The controller 25 constantly executes the braking control process for the electric brakes 1FL to 1RR shown in FIG. In this braking control process, first, a brake operation amount S indicating the amount of depression of the brake pedal 22 detected by the brake operation amount sensor 24 in steps S1, S2, and S3 and a pressing force sensor 17i (i = FL, FR, RL). , RR) and the bending moment Mi detected by the bending moment sensor 8i are read, and then the process proceeds to step S4.

In this step S4, the above-mentioned step S1
It is determined whether or not the brake operation amount S read in step ₃ exceeds the pedal play amount S _{0. If the} result of this determination is S ≦ S _0, it is determined that the vehicle is in the non-braking state and the process returns to step S1.
On the other hand, when the result of this determination is S> S _0, it is determined that the vehicle is in the braking state, and the process proceeds to step S5. In this step S5, the brake operation amount S and the target braking torque T shown in FIG.
^The target braking torque T ^* is calculated based on the brake operation amount S read in step S1 with reference to the target braking torque calculation control map showing the relationship with ^* . This target braking torque calculation control map is stored in advance in the memory of the controller 25.

Here, in the target braking torque calculation control map, as shown in FIG. 4, the horizontal axis represents the brake operation amount S and the vertical axis represents the target braking torque T ^* , and the value of the brake operation amount S is the pedal. When the amount of play S ₀ or less, the target braking torque T ^*
Becomes 0, and when the brake operation amount S increases beyond the pedal play amount S ₀ , the target braking torque T ^* is also set to increase accordingly.

Next, in step S6, the braking torque T generated on the wheels is calculated. Where caliper 3
Can be represented by a U-shaped rigidity model as shown by the bold line in FIG. The inner pad 4b side of the disc rotor 2 has a pressing force distribution center position at the position R _IN from the shaft center of the disc rotor 2, and the outer pad 4a side has a pressing force distribution center position at the position R _OUT from the shaft center of the disc rotor 2. At this central position of the pressing force distribution, the pressing force F of the brake friction member 4 against the disc rotor 2
Occurs, the reaction force F is generated on the outer pad 4a and the inner pad 4b regardless of the deformation of the caliper 3.

The braking torque T generated on the wheels is
As shown in FIG. 5B, the sum of the braking torque generated on the outer pad 4a side and the braking torque generated on the inner pad 4b side is calculated from the reaction force F, the friction coefficient μ, and the axial center of the disc rotor 2. Center position of the pressing force distribution of R _IN and R _OUT
It can be expressed by the following equation (1) using and. T = (μ · F · R _IN ) + (μ · F · R _OUT ) = μ · F · (R _IN + R _OUT ) (1) Then, the brake friction member 4 for the disc rotor 2
When the reaction force F is generated by the pressing, the open side of the U-shaped rigid model is expanded and deformed into a C-shape as shown in FIG.
A bending moment M that causes the central portion to bend toward the disc rotor 2 side is generated. The bending moment M is determined by the rigidity km of the caliper, the bending moment measuring portion R ₀ from the axis of the disk rotor 2, the center position R _OUT of the pressing force distribution of the outer pad 4a from the axis of the disk rotor 2, and the inner pad 4b. Based on the center position of the pressing force distribution of and the reaction force F to the brake friction member 4, according to the following equation (2),
Can be represented. M = km · F · (R ₀ −R _IN ) + km · F · (R ₀ −R _OUT ) (2) Then, the formula (2) is transformed into the following formula (3). Then, by substituting this equation (3) into the above equation (1), the following equation (4) can be derived. F · (R _IN + R _OUT ) = 2 · F · R ₀ −M / km ··· (3) T = μ · (2 · F · R ₀ −M / km) ··· (4) Therefore, the friction coefficient μ between the disc rotor 2 and the brake friction member 4, the caliper rigidity km, and the bending moment measurement portion R ₀ from the axial center of the disc rotor 2 are stored in the memory of the controller 25 in advance. Since it is stored, braking is performed by the pressing force Fi of the brake friction member against the disc rotor 2 (reaction force F against the brake friction member 4) read in step S2 and the bending moment Mi read in step S3. The torque Ti can be calculated.

Next, in step S7, the difference between the target braking torque T ^* calculated in step S5 and the braking torque Ti calculated in step S6 is multiplied by a coefficient a to brake the electric motor 9. By calculating the control amount Ci and outputting the braking control amount Ci to the drive circuits 26A and 26B in step S8, the drive control for the electric motor 9 in the electric brakes 1FL to 1RR is executed, and then the step S1 is performed. Return to.

In the process of FIG. 3, the process of step S1 and the brake operation amount sensor 21 correspond to the brake operation amount detecting means, the process of step S2 and the pressing force sensor 8i correspond to the pressing force detecting means, and the step The processing of S3 and the bending moment sensor 8i correspond to the bending moment detecting means, the processing of step S6 corresponds to the braking torque calculating means, and the processing of steps S7 and S8 corresponds to the braking control processing.

Therefore, when the vehicle is in a running state and the driver is not operating the brake pedal 22 in a non-braking state, the brake friction member 4 is separated from the contact position with the disc rotor 2 by a certain amount. It is in the initial position. If no braking operation is performed by the driver, the non-braking state is continued, and when the braking operation is started, the controller 25 performs the braking control based on the target braking torque T ^* calculated from the operation amount S of the brake pedal 22. To start.

Here, the control accuracy when the pressing force Fi detected by the pressing force sensor 8i is subjected to the braking control based on the target braking torque T ^* is plotted on the horizontal axis as shown in FIG. 6 (a). Regarding the relationship between the pressing force F and the braking torque T taken on the vertical axis, when the brake friction member 4 has no uneven wear and the pressing force distribution center position R is at the axial center of the brake friction member 4, its characteristic curve L1 On the other hand, a change in the friction coefficient μ between the disc rotor 2 and the brake friction member 4 causes only a minute error indicated by the alternate long and short dash line and the dotted line. However, due to the progress of uneven wear of the brake friction member 4, like the characteristic curve L2 when the pressing force distribution center position R moves to the inner peripheral side of the disk rotor 2 and the characteristic curve L3 when it moves to the outer peripheral side, The actual braking torque T against the pressing force F detected by the pressing force sensor 8i is caused by the fluctuation of the pressing force distribution center position R due to the uneven wear of the brake friction member 4.
Will change.

Therefore, in order to cope with the fluctuation of the pressing force distribution center position R due to the uneven wear of the brake friction member 4, the disk rotor 2 and the brake stored in the memory of the controller 25 in advance are stored according to the above equation (4). Friction member 4
And the coefficient of friction μ between the axis of the disc rotor 2, the bending moment measurement position R ₀ and the rigidity km, and the pressing force Fi read by the pressing force sensor 8i and the bending moment Mi read by the bending moment sensor 8i. The braking torque Ti is calculated.

Next, the braking control amount C is calculated so that the braking torque Ti matches the target braking torque T ^* .
By outputting the braking control amount C to the electric motor 9 via the drive circuits 26A and 26B, the electric motor 9 is rotationally driven, for example, in the clockwise direction, and the ball screw shaft 11 is also rotated in the clockwise direction via the rotating shaft 9a. The ball nut 13, which is rotationally driven and screws the ball screw shaft 11, is prevented from rotating by the engagement with the inner peripheral wall of the caliper 3 and only linear movement is allowed, so that the brake friction member 4 is pressed against the disc rotor 2. The desired braking torque is obtained.

In this way, by controlling the electric motor 9 so that the calculated braking torque T matches the target braking torque T ^* , as shown in FIG. 6B, the uneven wear of the brake friction member 4 is accompanied. Even if the pressing force distribution center position R deviates from the axial center of the brake friction member 4, only a minute error indicated by the alternate long and short dash line and the dotted line occurs due to the variation of the friction coefficient μ, and the braking torque T with respect to the pressing force F is always maintained. You can be stable.

After that, when the driver reduces the depression amount of the brake pedal 23, the target braking torque T ^* corresponding to the reduction amount of the brake operation amount S is generated on the wheels, but the electric motor 9 is turned on the contrary. The inner pad 4b is retracted to reduce the braking force by rotating the wheel counterclockwise and following the procedure opposite to that at the time of braking. Then, when the brake pedal 23 is returned to the released state by continuing the reduced state of the brake operation amount, the electric motor 9 is further rotated counterclockwise to rotate the brake friction member 4 from the disc rotor 2 by a predetermined amount. The braking torque is released by returning to the initial position separated by only.

As described above, according to the first embodiment, the brake friction member 4 is unevenly worn, and the center position R of the pressing force distribution with respect to the disc rotor 2 is deviated from the axial center of the brake friction member 4. Even in this case, the braking torque calculated from the pressing force F, the bending moment M, the bending moment measurement position R ₀ from the axial center of the disc rotor 2, the friction coefficient μ, and the caliper rigidity km is the braking operation amount S. Since the control is performed so as to match the target braking torque T ^* calculated from, the braking control can be performed with high accuracy, and the braking balance of the four wheels can be favorably maintained.

Next, a second embodiment of the present invention will be described with reference to FIGS.
And it demonstrates based on FIG. This second embodiment is
By providing a common sensor for detecting the pressing force and the bending moment, the pressing force sensor 17 in the above-described first embodiment is omitted, and the bending moment M is detected with high accuracy. That is, in the second embodiment, as for the detection of the pressing force F and the bending moment M, as shown in FIG. 7, the pressing force sensor 17 in the above-described first embodiment is omitted and replaced with the bending moment sensor 8. , The outer peripheral portion and the inner peripheral portion of the bridge portion 7 of the caliper 3,
The pressing force F is calculated based on the strain output values detected by the outer peripheral strain sensor 28a and the inner peripheral strain sensor 28b, respectively.
And except that the bending moment M is calculated
2 has the same configuration as that of the first embodiment, the same reference numerals are given to the portions corresponding to those in FIG. 2, and the detailed description thereof will be omitted.

As shown in FIG. 8, the braking control process executed by the controller 25 is the same as the step S in the braking control process of FIG. 3 in the first embodiment described above.
2 and the processing of step S3, the strain amounts ε _OUT and ε detected by the outer peripheral strain sensor 28a and the inner peripheral strain sensor 28b.
Instead of the processing of step S21 for reading _IN ,
Further, except that the processing in step S6 is replaced by step S22 in which the braking torque T is calculated based on the strain amounts ε _OUT and ε _IN read in step S21, as shown in FIG.
The same processing is executed, the processing corresponding to FIG. 3 is denoted by the same reference numeral, and detailed description thereof is omitted.

In the braking torque calculation process in step S22, the braking torque Ti is calculated based on the outer peripheral strain amount ε _OUT i and the inner peripheral strain amount ε _IN i read in step S21. First, the disc rotor 2 generated in the bridge portion 7
Bending moment M in the radial direction and the disk rotor 2
The pressing force F of the brake friction member 4 with respect to can be expressed by the following equations (5) and (6). Note that K ₁ and K ₂
Is a proportional coefficient calculated by experiments, numerical analysis, etc., but the tensile rigidity K of the bridge portion 7 may be used as an approximate value. _{M = (ε IN -ε OUT)} K 1/2 ········· (5) F = (ε IN + ε OUT) K 2/2 ········· (6) These By substituting the equations (5) and (6) into the equation (4) for calculating the braking torque T in the above-described first embodiment, the following equation (7) can be derived. _{T = μ · {(ε IN} + ε OUT) K 2 · R 0 - (ε IN -ε OUT) K 1 / 2km} based on (7) Thus the equation (7), the outer peripheral portion the strain amount epsilon _OUT After calculating the braking torque Ti from i and the inner peripheral strain amount ε _IN i, the process proceeds to step S7, and the calculated braking torque T
i is the target braking torque T calculated from the brake operation amount S
^The braking control amount Ci that matches ^* is calculated.

Here, when the braking torque T is generated, as shown in FIG. 9 (a) which is an enlarged view of the bridge portion 7 of the caliper 3, the bridge portion 7 has a radius from the position shown by the dotted line to the radius of the disk rotor 2 shown by the solid line. Bends in the direction.
At this time, compression due to bending occurs in the outer peripheral portion of the bridge portion 7 and extension due to bending occurs in the inner peripheral portion, and at the same time, extension as tensile force due to reaction force occurs in the outer peripheral portion and the inner peripheral portion. .

As shown in FIG. 9 (b), the relationship between the inner and outer peripheral portions of the bridge portion and the displacements thereof is as shown in FIG. As shown in the figure, in actuality, the extension as a tensile force due to the reaction force is added, so that the characteristics are changed to those indicated by thick lines. Therefore, the extension due to the tension is further added to the extension due to the bending at the inner peripheral portion, and the compression due to the bending is canceled at the outer peripheral portion by the extension due to the tension, so that the inner peripheral portion is in a non-braking state compared to the outer peripheral portion. The amount of distortion from is large.

As described above, according to the second embodiment, the outer peripheral strain sensor 28a in the bridge portion 7 of the caliper 3 is.
By providing the inner peripheral portion strain sensor 28b, the pressing force of the brake friction member 4 can be detected without the pressing force sensor 8, and the bending moment of the bridge portion 7 in the radial direction of the disc rotor 2 can be detected. It is possible to accurately detect M and accurately control the braking torque that acts on the wheels.

In the second embodiment described above, the configuration in which the strain sensor 27 is arranged on the outer peripheral portion and the inner peripheral portion of the bridge portion 7 has been described, but the present invention is not limited to this, and stress or displacement is not limited thereto. Is proportional to the strain, and the proportional coefficient thereof is known or can be calculated, so that a stress sensor or a displacement sensor may be used instead. Next, a third embodiment of the present invention will be described with reference to FIGS.

In the third embodiment, the disk rotor 2
The pressing force F against is detected from the position of the inner pad 4b forming the brake friction member 4. That is, in the third embodiment, as shown in FIG. 10, the same configuration and processing procedure as in the first embodiment are omitted except that the pressing force sensor 8 in the first embodiment described above is omitted. 2, corresponding parts to those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

Between the position of the inner pad 4b and the pressing force F, as shown in FIG. 11, the pressing force F increases in accordance with the movement of the inner pad 4b toward the disc rotor 2 side. There is a rigidity ks that represents Therefore,
The controller 25 uses the control map based on this rigidity ks.
It is stored in advance in the memory of the inner pad 4b.
The pressing force F can be calculated from the position. The inner pad position is calculated based on the rotation angle and rotation direction of the electric motor 9 read by the rotary encoder 15 and the pitch of the ball screw.

As described above, according to the third embodiment described above, the pressing torque to the disk rotor 2 is detected from the position of the inner pad 4b without providing a pressing force sensor, and the braking torque T applied to the wheels is detected. Can be controlled accurately. In addition, in the said 3rd Embodiment, although the structure which judges the position of the inner pad 4b from the drive state of the electric motor 9 was demonstrated, it is not limited to this, For example, the electric signal according to a distance is sent. Inner pad 4 using position sensor such as output eddy current displacement sensor
The position of b may be detected.

Further, in the first, second and third embodiments, the front left electric brake 1FL and the rear right electric brake 1RR and the front right electric brake 1FR and the rear right electric brake 1RL are controlled by separate control systems. Although the case where the control is performed has been described, the present invention is not limited to this, and separate control systems are provided in the front and rear, and the electric brake 1F.
The L to 1 RRs may be independently controlled.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing an electric brake.

FIG. 3 is a flowchart showing an example of a braking control processing procedure executed by a controller in the first embodiment of the present invention.

FIG. 4 is a target braking torque calculation control map for calculating a target braking torque from a brake operation amount in the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a method of calculating a braking torque in the first embodiment of the present invention.

FIG. 6 shows that in the first embodiment of the present invention, the braking control accuracy changes when the braking control is performed based on the pressing force and when the braking control is performed based on the braking torque. FIG.

FIG. 7 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 8 is a flowchart showing an example of a braking control processing procedure executed by a controller in the second embodiment of the present invention.

FIG. 9 is an explanatory diagram showing that strain is generated in the outer peripheral portion and the inner peripheral portion of the bridge portion during braking in the second embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a third embodiment of the present invention.

FIG. 11 is a control map showing the relationship between the inner pad position and the pressing force in the third embodiment of the invention.

FIG. 12 is an explanatory diagram showing that, due to uneven wear of the brake friction member, the pressing force against the disk rotor and the braking torque actually applied to the wheels differ in the conventional example.

[Explanation of symbols]

2 disk rotor 3 calipers 4a outer pad 4b Inner pad 5 Electric drive mechanism 7 bridge 8 Bending moment sensor (bending moment detection means) 9 Electric motor 10 Linear conversion mechanism 11 Ball screw shaft 13 Ball nut 15 rotary encoder 17 Pressing force sensor (pressing force detection means) 18 Control mechanism 23 Brake pedal 24 Brake operation amount sensor 25 controller 28a Peripheral strain sensor 28b Inner peripheral strain sensor

Claims (3)

[Claims] 1. A brake operation amount detecting means for detecting an operation amount of a brake operating means by a driver, a holding portion for straddling and holding a brake friction material with respect to a rotating body rotating with a wheel, and the rotating body. An electric drive mechanism that controls the pressing force of the brake friction material with respect to the electric drive mechanism, and a braking control unit that controls the braking control amount for the electric drive mechanism based on the brake operation amount detected by the brake operation amount detection unit. In the brake device, a pressing force detecting means for detecting a pressing force of the brake friction material, a bending moment detecting means for detecting a bending moment of the holding portion in the radial direction of the rotating body, and a pressing force detecting means for detecting the bending moment. Braking for calculating the braking torque generated in the wheel based on the applied pressing force and the bending moment detected by the bending moment detecting means. And a braking control means for braking the electric drive mechanism so that the braking torque calculated by the braking torque calculation means and the brake operation amount detected by the brake operation amount detection means have a predetermined relationship. An electric brake device, which calculates and outputs a drive amount. 2. The pressing force detecting means and the bending moment detecting means measure any of strain, stress and displacement of an outer peripheral portion and an inner peripheral portion of a portion of the holding portion straddling the rotating body. The electric brake device according to claim 1, further comprising a measuring unit common to the two units. 3. A friction material position detecting means for detecting a position of the brake friction material, wherein the pressing force detecting means comprises the brake friction material position detected by the friction material position detecting means and the brake friction material. The electric braking device according to claim 1 or 2, wherein the pressing force is detected based on a rigidity indicating a relationship between a material position and the pressing force.