JP2005233288A - Motor-driven brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a countermeasure for a motor-driven brake against improper temperature rise. <P>SOLUTION: If an improper temperature rise is sensed in the motor-driven brake in the condition that the brake disengagement continues for the set time or longer (S3), occurrence of trailing is informed (S4), and a motor is rotated in the brake disengaging direction for eliminating the trailing (S5). If improper temperature rise is sensed in the motor-driven brake immediately after the start of the braking (S9), occurrence of trailing is informed (S10), and the brake disengaging position is shifted further in the disengaging direction from the brake disengaging position till the time for eliminating the trailing (S11). At braking with the braking rate being equal to or above the set value, a generation of heat-fade is sensed by sensing an excessive shortage of the braking force (S12). In the event of generation of a heat-fade, this is informed (S13) and a heat-fade control is conducted (S14). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric brake device, and particularly relates to a countermeasure against an inappropriate temperature increase of the electric brake.

The electric brake device is known from Patent Documents 1 and 2 listed below. In Patent Document 1, a temperature sensor is provided in the electric brake, and a current supplied to the electric motor is controlled based on a temperature detected by the temperature sensor, so that the pressing force of the friction material to the disk rotor can be accurately set regardless of temperature fluctuations. It is described that the value is controlled. The electric brake includes an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into a pressing motion of the friction material. However, the operating resistance of the motion conversion mechanism becomes an invalid torque of the electric motor, and It is desirable to correct the rotational torque by an ineffective torque. However, since the operating resistance varies depending on the temperature, it is desirable to change the correction value for the ineffective torque based on the temperature detected by the temperature sensor.
JP 2003-106355 A JP 2002-13566 A

  Also, in Cited Document 2, when the temperature of one of the electric brakes provided on each of the left and right wheels exceeds the upper limit allowable temperature and the supply current is reduced to protect the electric motor, the left and right wheels are controlled. An invention that solves the problem of power difference and the problem of difference in output torque with respect to the same control signal because the temperature of the electric motors on the left and right wheels is different from each other, and obtains a good braking force regardless of temperature change is described. ing.

  On the other hand, in the present invention, the caliper straddling the disc-shaped brake rotor incorporates an electric motor and a motion conversion mechanism that converts the rotation of the electric motor into a motion that presses the friction member against the brake rotor. An object of the present invention is to detect the drag of the electric brake at an early stage by detecting an inappropriate temperature rise of the electric brake.

  In order to solve the above problems, an electric brake device according to the present invention includes: (a) an electric brake; (b) a temperature detection device that detects the temperature of the electric brake; and (c) a brake release state that continues for a set time or longer. When the temperature detected by the temperature detection device exceeds the set temperature, the drag reduction unit is configured to rotate the electric motor in the brake release direction.

  Another electric brake device according to the present invention includes: (a) an electric brake; (b) an inappropriate temperature increase detection device that detects an inappropriate temperature increase of the electric brake; and (b) a motor control that controls the electric motor. A brake release position, which is a rotational position in the brake release state of the electric motor, when the inappropriate temperature rise is detected by the inappropriate temperature rise detection device. The brake release position changing unit is further included for changing the brake release position in the brake release direction.

  The inappropriate temperature rise detection device can detect an inappropriate temperature rise in the brake release state or can detect it in the brake operation state. In the former case, for example, a temperature sensor to be described later may be included, or a resistance detection device, a resistance / temperature relationship memory, and a temperature estimation unit may be included. Or a current supply command value acquisition unit, a braking force detection device, and an inappropriate temperature rise determination unit which will be described later.

  In the electric brake device including the temperature detection device and the drag reduction unit, when the brake release state continues for a set time or more and the temperature of the electric brake exceeds the set temperature, the drag reduction unit sets the electric motor. It is rotated in the brake release direction. The reason why the temperature of the electric brake rises so as to exceed the set temperature even though the brake release state continues for the set time or longer is because dragging has occurred. The electric motor is rotated in the brake release direction, the brake clearance is increased, and drag is eliminated. The set temperature is set to a temperature at which the brake temperature does not rise to that temperature depending on the outside air temperature or the like, and to the temperature when dragging occurs.

  Further, in the electric brake device including the inappropriate temperature rise detection device and the brake release position changing unit, when the inappropriate temperature rise detection device detects an inappropriate temperature rise of the electric brake, the brake release position changing unit The brake release position is changed further in the brake release direction than the previous brake release position. In an electric brake, when the brake is released, the electric motor can be reversely rotated to a position where the brake clearance can be secured (rotation in the direction in which the brake is applied is referred to as normal rotation, and rotation in the release direction is referred to as reverse rotation). Therefore, it is common to reversely rotate to a preset brake release position, or to reversely rotate from the brake application position by the amount of rotation necessary for brake release. Although it is possible to set the brake release position fixedly, it is desirable that the brake release position is changed with wear of the brake friction member in order to avoid delay in effectiveness. In addition, the amount of rotation reversely rotated from the brake operating position can be set to a constant amount, but in consideration of the amount of elastic deformation of the caliper and the friction member, the driving torque in the positive direction (which may be actually detected) It is desirable that the amount of reverse rotation be increased as the value increases (which may be estimated based on the drive current in the forward direction). In any case, if the control of the electric motor is properly performed, the brake will not be dragged in the brake released state, but the reverse rotation amount of the electric motor for some reason such as malfunction of the motor control device. May be insufficient and drag may occur.

  In the present invention, when dragging occurs as described above, an inappropriate temperature rise is detected by the inappropriate temperature rise detection device, and the brake release position, which is the rotational position in the brake release state of the electric motor, is The position change unit changes the brake release direction further than the previous brake release position. Inappropriate temperature rise detection by the inappropriate temperature rise detection device may be performed when the electric brake is in the released state, in which case it is not essential that the brake release position be changed immediately. Is desirable. In addition, when the brake release position is changed, the electric motor may be immediately rotated to the brake release position after the change. You may make it rotate. In the former case, the drag is immediately eliminated, and in the latter case, the drag is prevented from occurring after the next operation. In addition, improper temperature rise detection by the improper temperature rise detection device may be performed in the state of operation of the electric brake. In that case, the electric motor reaches the brake release position after the change at the end of the braking. Rotated. The fact that the brake release position is changed during the operation of the electric brake means that the drag has occurred before the braking is started, and the occurrence of the drag is avoided after the braking is released. Become.

Aspects of the Invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following items, item (1) corresponds to claim 1 and item (6) corresponds to claim 2.

(1) An electric brake in which an electric motor and a motion conversion mechanism that converts rotation of the electric motor into a motion of pressing the friction member against the brake rotor are incorporated in a caliper straddling the disc-shaped brake rotor;
A temperature detecting device for detecting the temperature of the electric brake;
A motor control device that controls the electric motor, and the motor control device is in a state where the brake detection state continues for a set time or more and the temperature detected by the temperature detection device exceeds the set temperature. An electric brake device comprising a drag reducing portion for rotating the electric motor in a brake releasing direction.
(2) The electric brake device according to (1), wherein the temperature detection device includes a temperature sensor that is provided in a predetermined temperature detection unit of the electric brake and detects a temperature of the temperature detection unit.
According to the temperature sensor, it is possible to accurately obtain the temperature of a predetermined portion of the electric brake.
(3) The temperature detecting device is
A resistance detection device for detecting a resistance value of a coil of the electric motor;
A resistance / temperature relationship memory storing the relationship between the resistance value of the coil of the electric motor and the temperature of the coil;
The temperature estimation unit for estimating the temperature of the coil based on the resistance / temperature relationship stored in the resistance / temperature relationship memory and the resistance value detected by the resistance detection device (1) or The electric brake device according to item (2).
According to the aspect in which this term is subordinate to the term (1), the temperature sensor can be omitted.
(4) The electric brake device according to any one of (1) to (3), wherein the drag reducing unit rotates the electric motor in a brake release direction by a predetermined rotation amount.
When the temperature rise gradient when the detected temperature exceeds the set temperature is large, the reverse rotation amount is set according to the heating state of the electric motor, for example, the reverse rotation amount of the electric motor is increased compared to the case where the detected temperature is small. Although it is possible to make it rotate, it is easy to control if it is rotated by a certain amount.
(5) The electric brake device according to any one of (1) to (4), further including a drag information creating unit that creates drag information when the temperature detected by the temperature detecting device exceeds a set temperature. .
The created drag information can be used, for example, to operate a notification device that notifies the driver of the occurrence of drag.
(6) An electric brake in which an electric motor and a motion conversion mechanism that converts rotation of the electric motor into a motion of pressing the friction member against the brake rotor are incorporated in a caliper straddling the disc-shaped brake rotor;
An inappropriate temperature rise detection device for detecting an inappropriate temperature rise of the electric brake;
A motor control device for controlling the electric motor, and when the motor control device detects an inappropriate temperature rise by the inappropriate temperature rise detection device, An electric brake device comprising: a brake release position changing unit for changing a certain brake release position in a brake release direction further than a brake release position so far.
(7) The electric brake device according to (6), wherein the brake release position changing unit includes a constant amount changing unit that changes the brake release position by a predetermined amount.
(8) The brake release position changing unit sets the brake release position when the inappropriate temperature rise amount or the rising gradient detected by the inappropriate temperature rise detection device is large, as compared with a small case. The electric brake device according to item (6) or (7), including an inappropriate temperature rise amount change unit that changes a large amount.
(9) The inappropriate temperature rise detection device is
A current supply command value acquisition unit for acquiring a current supply command value to the electric motor;
A braking force detection device for detecting a braking force of the electric brake;
In the initial stage of braking after the brake release state has continued for a set time or longer, the braking force detected by the braking force detection device is predetermined with respect to the current supply command value acquired by the current supply command value acquisition unit. Any one of (6) to (8), including an inappropriate temperature rise determination unit that determines that the inappropriate temperature rise has occurred when the braking force is smaller than the first set amount. The electric brake device described in 1.
When the temperature of the electric motor rises, even when current is supplied to the electric motor under the same conditions such as applied voltage and duty ratio, the driving torque is reduced as compared with the case where the temperature of the electric motor is low. Accordingly, the current supply command value at the time of braking (this is determined based on the operation amount of the brake operation member, the operation stroke, etc., and the applied voltage, the duty ratio, etc. are determined according to this current supply command value). On the other hand, when the generated braking force is small, it is reasonable to determine that an inappropriate temperature rise has occurred. If that is the initial stage of braking after the brake has been released for more than the set time, It can be estimated that the brake drag occurred before the start of braking, and the temperature of the electric motor was inappropriately increased.
(10) When the motor control device performs braking in a state where the braking rate of the electric brake is equal to or higher than a set rate, the braking force detected by the braking force detection device is acquired by the current supply command value acquisition unit. The item (9) includes a current increasing unit that increases the current supply command value to the electric motor when the current supply command value is smaller than the second set amount by comparison with a braking force determined in advance. The electric brake device described.
When the braking rate of the electric brake is equal to or higher than the set rate, there is a high possibility that the temperature of the electric motor will rise inappropriately due to overheating of the brake mechanism. Therefore, the braking force of the electric brake is equal to or higher than the set rate, and the braking force detected by the braking force detection device becomes a braking force that is predetermined with respect to the current supply command value acquired by the current supply command value acquisition unit. When the second set amount is smaller than the comparison, it is reasonable to increase the current supply command value to the electric motor in the current increasing section, assuming that the brake is overheated and the friction coefficient of the friction member is excessively decreased. That is. The increase in the current supply command value to the electric motor by the current increasing unit can be a predetermined constant amount. For example, as in the next item, the amount can be increased according to the decrease in the friction coefficient. desirable.
According to this section, the shortage of braking force due to heat fade can be suppressed or avoided by using the current supply command value acquisition unit and the braking force detection device, which are components of the inappropriate temperature rise detection device.
(11) The electric brake device includes an operation amount detection device that detects an operation amount of a brake operation member operated by a driver, and the current increasing unit is configured by the braking force detection device (or braking force acquisition device). (10) The current supply command value to the electric motor is increased until the detected (or acquired) braking force becomes a magnitude corresponding to the operation amount detected by the operation amount detection device. The electric brake device described.
According to this section, it is possible to obtain a braking force according to the operation amount (for example, operation force, operation stroke, etc.) of the brake operation member operated by the driver, despite the brake being overheated.
(12) The inappropriate temperature rise detection device is
A temperature sensor for detecting the temperature of the electric brake;
An inappropriate temperature rise determination unit that determines that the inappropriate temperature rise has occurred when a temperature detected by the temperature sensor exceeds a set temperature in a state where the brake release state continues for a set time or more; The electric brake device according to any one of (6) to (11).
(13) including an inappropriate temperature rise information creation unit that creates inappropriate temperature rise information in response to detection of the inappropriate temperature rise by the inappropriate temperature rise detection device; The electric brake apparatus in any one.
Based on the generated inappropriate temperature rise information, the alarm device for informing the driver of the occurrence of inappropriate temperature rise is operated, or it is supplied to other control devices that control devices other than the brake, and the control is performed. The control by the device can be changed.
(14) When the brake release position changing unit changes the brake release position when the electric brake is in the release state, the motor control device immediately eliminates the dragging that immediately rotates to the brake release position after the change. The electric brake device according to any one of (6) to (13).
In the electric brake device of this section, when the occurrence of dragging is detected in the brake released state, the drag is immediately eliminated.

  Several embodiments of the claimable invention will now be described in detail with reference to the drawings. In addition to the following examples, the claimable invention can be practiced in various modifications based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. .

  FIG. 1 shows only a portion deeply related to the present invention in the electric brake device as one embodiment. In the present electric brake device, the depression force of the brake pedal 10 by the driver is detected by the depression force sensor 12, and the rotation of the electric motor 16 as a drive source is controlled by the controller 14 based on the detected depression force. . As a result, when the pressing member 18 presses the brake pad 20 against the brake rotor 22, a braking force corresponding to the pedaling force is generated.

  In FIG. 1, 30 is a caliper that straddles the disc-shaped brake rotor 22. The caliper 30 is supported by a mounting bracket (not shown) fixed to a non-rotating part (a knuckle, an axle tube, etc.) of a vehicle (not shown) so as to be floatable in the axial direction that is the direction of the rotation axis of the brake rotor 22. . The mounting bracket further supports a pair of brake pads 20 as friction members so as to be movable in the axial direction of the brake rotor 22. The caliper 30 includes a caliper main body 34 including a claw portion 32, and the claw portion 32 is close to the back surface of the brake pad 20 positioned on the vehicle outer side (surface opposite to the surface facing the brake rotor 22). Has been placed.

  The caliper 30 also includes a pressing member 18 that can contact the rear surface of the brake pad 20 inside the vehicle, an electric motor 16, and a motion conversion mechanism 40 that converts rotation of the electric motor 16 into linear motion of the pressing member 18. I have. Although the detailed illustration of the motion conversion mechanism 40 is omitted, for example, a ball ramp mechanism described in JP 2003-106355 A can be used. The electric motor 16 is a well-known motor, and detailed illustration and description thereof are omitted. However, the electric motor 16 includes a stator including a coil and a rotor including an electromagnet, and current is supplied to the coil based on a current supply command from the controller 14. As a result, the rotor is rotated. The rotation angle (rotation position) of the rotor is detected by an encoder 42 as a rotation angle detection device, and the rotation of the electric motor 16 is controlled based on the detection result. The motion conversion mechanism 40 converts the rotational motion of the rotor of the electric motor 16 into a linear motion to advance the pressing member 18 and press the pair of brake pads 20 arranged on both sides of the brake rotor 22 against the brake rotor 22. Brake force is generated. In this way, the state where the braking force is generated is referred to as an operating state of the electric brake. The rotation of the electric motor 16 in the direction in which the brake pad 20 is pressed against the brake rotor 22 is referred to as positive direction (brake acting direction) rotation. Further, by rotating the electric motor 16 in a direction opposite to the normal direction (brake release direction), the pressing member 18 is retracted, and the pressing of the pair of brake pads 20 to the brake rotor 22 is released. In this way, the state in which the pressure applied to the brake rotor 22 by the brake pad 20 is released is referred to as an electric brake released state.

  The electric brake is controlled by the controller 14. The controller 14 is mainly composed of a computer 50, and the computer 50 includes a CPU, a ROM 52, a RAM 54, and the like. The controller 14 (computer 50) includes a pedal force sensor 12, an encoder 42, a brake switch 60 that detects the depression of the brake pedal 10, a speed sensor 62 that detects the traveling speed of the vehicle, a resistance value detection device 64 and a braking force that will be described later. A detection device 66 and the like are connected. The resistance value detection device 64 is a device that detects a resistance value of a coil by passing a weak current through the coil of the electric motor 16 in a state where no current flows through the electric motor 16. The braking force detection device 66 is a device for detecting the braking force of the electric brake. In this embodiment, the braking force detection device 66 includes a strain gauge attached to the mounting bracket. With this strain gauge, the force applied to the mounting bracket based on the torque (continuous torque) that the brake pad 20 tries to rotate with the brake rotor 22 during braking is detected as a braking force. The controller 14 (computer 50) is also connected to the electric motor 16, the notification device 68, and the like. The notification device 68 can be notified by at least one of sounding of a buzzer, lighting of a lamp, blinking of a lamp, and display of images such as characters and graphics on a display screen.

  As shown in FIG. 2, the ROM 52 of the computer 50 includes a control program memory 70 for storing a control program for controlling the electric brake device, a resistance / temperature relationship map 72, a current / braking force relationship map 74, A pedaling force / braking force relationship map 76, a set temperature memory 78, and the like are provided. The resistance / temperature relationship map 72 is a map representing the relationship between the resistance value of the coil of the electric motor 16 and the temperature of the coil, and the current / braking force relationship map 74 is the current value supplied to the electric motor 16 and the electric motor. The map represents a normal relationship with the braking force of the brake, and the pedaling force / braking force relationship map 76 is a map representing the normal relationship between the pedaling force of the brake pedal 10 by the driver and the braking force of the electric brake. The set temperature memory 78 stores a set temperature t1 that does not increase to the temperature depending on the outside air temperature or the like, and increases to that temperature when dragging occurs.

  As shown in FIG. 3, the RAM 54 of the computer 50 is provided with a release state duration memory 80, a resistance value memory 82, an acquired temperature memory 84, a current supply command value memory 86, a braking force memory 88, a pedaling force memory 90, and the like. ing. In the release state duration memory 80, a time during which the release state of the brake pedal 10 by the driver has been continued is measured by a timer, and the value (duration) is stored. The resistance value memory 82 stores the resistance value of the electric motor 16 detected by the resistance value detecting device 64, and the acquisition temperature memory 84 stores the temperature of the electric motor 16 acquired by a method described later. The current supply command value memory 86 stores a current value commanded to be supplied from the controller 14 to the electric motor 16 (referred to as a current supply command value), and the braking force memory 88 stores the control value. The braking force of the electric brake detected by the power detection device 66 is stored, and the pedaling force memory 90 stores the pedaling force of the brake pedal 10 detected by the driver by the pedaling force sensor 12.

  The control programs stored in the control program memory 70 are shown in flowcharts in FIGS. However, normal control of the electric brake, such as control of the electric motor 16 corresponding to the depression force of the brake pedal 10 and control of changing the brake action position and the brake release position to the action direction with the wear of the brake pad 20, etc. Since this is a known one, its illustration is omitted here, and only the portion deeply related to the present invention is shown.

  Hereinafter, the operation of the electric brake device will be described based on the flowchart. In the flowchart of FIG. 4, in step 1 (hereinafter referred to as “S1”, the same applies to other steps), the vehicle traveling speed detected by the speed sensor 62 as to whether or not the vehicle is traveling is equal to or higher than a set value. It is determined by whether or not. If the vehicle is running, the determination is yes and steps S2 and after are executed. If the determination in S1 is NO, one execution of this program ends. In S2, it is determined whether or not the release state of the brake pedal 10 continues for a set time or more. If the release state duration is measured by execution of a program (not shown) and stored in the release state duration memory 80, the determination is YES and S3 is executed. In S3, it is determined whether or not the temperature of the electric motor 16 is inappropriate.

  The contents of S3 are shown in the flowchart of FIG. In S 20, the resistance value is read from the resistance value detection device 64 and stored in the resistance value memory 82. Next, in S21, the estimated temperature of the coil of the electric motor 16 is acquired based on the resistance / temperature relationship stored in the resistance / temperature relationship map 72 and the read resistance value. The acquired temperature is stored in the acquired temperature memory 84 of the RAM 54. In S22, it is determined whether or not the acquired temperature is higher than the set temperature t1. If the determination in S22 is NO, one execution of the program is terminated, and if the determination is YES, S4 and subsequent steps in the flowchart of FIG. 4 are executed. That is, in S3, if the temperature of the electric motor 16 is higher than the set temperature t1, it is determined that the temperature of the electric motor 16 has risen inappropriately. The reason why the temperature of the electric brake increases as the electric brake temperature exceeds the set temperature t1 in spite of the brake release state continues for the set time or longer is because the brake pad 20 keeps contacting the brake rotor 22. In S4, information indicating that dragging has occurred is created, and the notification device 68 is activated to notify the driver of the dragging. In S5, the electric motor 16 is rotated by a certain amount in the direction opposite to the forward direction in order to release the drag. As a result, the brake clearance is increased and dragging is eliminated. As described above, the coil temperature can be estimated based on the resistance value of the coil of the electric motor 16 and the resistance / temperature relationship map 72. If the temperature of the electric motor 16 increases, the temperature This is because the resistance value of the coil is increased as compared with the case where it is low.

  In S2, if the release state of the brake pedal 10 has not continued for the set time or more and the determination is NO, S6 is executed to determine whether braking is being performed. If the brake is being performed and the determination is YES, S7 is executed, and it is determined whether or not the braking rate is greater than or equal to the set rate. The braking rate in the present embodiment is represented by the sum of products of braking time and braking force within a fixed time. If it is determined that the braking rate is greater than or equal to a predetermined set rate, the brake pad is caused by at least one of frequent braking within a predetermined time and generation of a strong braking force. Therefore, it is determined that there is a high possibility that heat fading has occurred due to an increase in the amount of heat generated at 20. However, the braking rate may be a total braking time within a certain time or a ratio obtained by dividing the total braking time by a certain time. If the determination in S7 is NO, it is determined in S8 whether or not the brake release state is the initial stage of braking after the set time has elapsed (immediately after the start of braking). If the determination in S8 is YES, it is determined in S9 whether or not an inappropriate temperature rise has occurred in the electric motor 16.

  The contents of S9 are shown in the flowchart of FIG. In S <b> 30, the current supply command value at that time is read from a portion that executes a brake control program (not shown) and stored in the current supply command value memory 86. In S 31, the braking force detected by the braking force detection device 66 is read and stored in the braking force memory 88. In S32, it is determined whether or not an appropriate braking force is generated for the acquired current supply command value. The determination in S32 is based on the current / braking force relationship stored in the current / braking force relationship map 74 described above, and the braking force predetermined for the acquired current supply command value and the read value. This is done by comparing with the braking force. If the determination in S32 is YES, one execution of this program ends. If the determined actual braking force is smaller than the standard braking force corresponding to the current supply command value by a first set amount or more, and the determination in S32 is NO, dragging has occurred before the start of the current braking. Thus, it is determined that there is a high possibility that an inappropriate temperature rise has occurred in the electric motor 16, and in S10, inappropriate temperature rise information is created, the notification device 68 is activated, and the driver is dragged. Informed. Subsequently, the brake release position is changed in S11. That is, the brake release position is changed further in the brake release direction than the previous release position. As a result, at the time of subsequent brake release, the electric motor 16 is further reversely rotated by a set amount from the previous brake release position. When it is detected that an inappropriate temperature rise has occurred in the electric motor 16, when the electric brake is in the released state, the change in the brake release position is immediately performed, so that the drag is immediately eliminated. However, in the active state, the electric motor 16 is rotated to the brake release position after the change at the end of the braking, thereby avoiding the occurrence of the drag after the brake is released.

  Moreover, if the said braking rate is more than a setting rate and determination of S7 is YES, S12 will be performed and it will be determined whether braking force is inappropriate. Since S12 is a step that can be executed in the same manner as S19, the description thereof is omitted here with reference to the description of S9. However, in S12, in the step corresponding to S32 of S9, the determination in this step (S32) is NO when the acquired current supply command value is smaller than the second set amount by a predetermined braking force. (In other words, the determination in S12 is YES) and the steps after S13 are executed. The second set amount is often set to a value larger than the first set amount. If the determination in S12 is NO, one execution of this program is completed, and if the determination is YES, it is highly likely that a heat fade has occurred in which the friction coefficient of the brake pad 20 is excessively decreased in S13. As a result, heat fade information is created, the notification device 68 is activated, and the driver is notified of the occurrence of heat fade. Subsequently, heat fade control is performed in S14. The contents of S14 are shown in the flowchart of FIG. In S <b> 40, the pedaling force detected by the pedaling force sensor 12 is read and stored in the pedaling force memory 90. In S 41, the braking force is read from the braking force detector 66 and stored in the braking force memory 88. In S42, it is determined whether or not the braking force is insufficient. The determination in S42 is made based on the pedal effort / braking force relationship map 76 stored in the ROM 52 described above. If the braking force is insufficient and the determination in S42 is YES, the braking force detected by the braking force detection device 66 in S43 has a magnitude corresponding to the pedaling force (operation amount) detected by the pedaling force sensor 12. Until that time, the supply current to the electric motor 16 is increased. If the determination in S42 is NO, it is determined in S44 whether or not the braking force is excessive. S44 is also determined based on the pedaling force / braking force relationship map 76. If the determination in S44 is YES, the supply current to the electric motor 16 is reduced in S45. If both the determinations in S42 and S44 are NO, the one-time execution of this program ends.

  In this embodiment, the resistance value detection device 64 that is a resistance detection device, the resistance / temperature relationship map 72 that is a resistance / temperature relationship memory, and the temperature estimation unit that is the portion that executes S21 in the control program of the controller 14 It constitutes a detection device. The controller 14 constitutes a motor control device. Furthermore, the portion of the controller 14 that executes S3 (S22) and S5 of the control program constitutes a drag mitigation unit. Furthermore, the part which performs S4 of a control program in the controller 14 comprises the drag information preparation part. The portion of the controller 14 that executes S11 of the control program constitutes a brake release position changing portion that is a constant amount changing portion. In the controller 14, the part that executes S9 (S30) of the control program and the current supply command value memory 86 constitute a current supply command value acquisition part, and the part that executes S9 (S31 and S32) is an inappropriate temperature rise determination part. Is configured. The current supply command value acquisition unit, the braking force detection device 66, and the inappropriate temperature rise determination unit constitute an inappropriate temperature rise detection device. The pedal force sensor 12 constitutes an operation amount detection device, and the portion of the controller 14 that executes S14 (S43) of the control program constitutes a current increasing portion. The portions of the controller 14 that execute S10 and S13 of the control program constitute an inappropriate temperature information creation unit. The portion of the controller 14 that executes S11 of the control program constitutes an instant drag elimination unit.

  As described above, according to the present embodiment, an inappropriate temperature rise of the electric brake can be detected in the brake released state, or can be detected in the brake applied state. When dragging occurs, an inappropriate temperature rise of the electric brake is detected, the occurrence of dragging is notified, and dragging is eliminated. In addition, when braking with a braking rate equal to or higher than the set rate, occurrence of heat fade can be detected by detecting an excessive shortage of braking force. When a heat fade occurs, it is possible to avoid a shortage of braking force due to the heat fade by notifying this and performing heat fade control.

  In the above embodiment, the coil temperature is estimated based on the resistance value of the coil of the electric motor 16 and the resistance / temperature relationship map 72. However, the temperature sensor is a temperature detection device that detects the temperature of the electric motor 16. And the temperature of the electric brake may be directly detected by the temperature sensor. The temperature sensor is provided, for example, in a temperature detection unit near the electric motor 16 of the caliper 30. Even in this case, the same control program as that in the above embodiment can be adopted. In S3 and S9, it is determined whether or not the temperature of the electric brake detected by the temperature sensor is inappropriate.

  In the above embodiment, the rotation position of the electric motor 16 is detected by the encoder 42 to control the rotation of the electric motor 16. Instead, the drive current supply in the forward direction or the reverse direction of the electric motor 16 is started. It is also possible to estimate the rotational position of the electric motor 16 based on this time. For example, the electric motor 16 is rotated in the forward direction, and the rotation position of the electric motor 16 in a state where the braking force is in a steady state is used as a reference, and the time from the start of supply of drive current in the reverse direction is measured from the reference rotation position The relative rotational position of the electric motor 16 with respect to the reference rotational position is estimated based on the time. Since the magnitude of the braking force in the steady state is usually proportional to the amount of elastic deformation of the caliper or the like of the electric brake, a reference value for the steady state braking force is determined in advance, and the reference steady braking force is determined in advance. The reference rotational position of the electric motor at each steady braking force is converted into the reference rotational position at the standard steady braking force based on the difference between the actual braking force at each steady state and the actual reference braking position. It is desirable to use it as a rotational position.

  The change amount of the brake release position when an inappropriate temperature rise of the electric brake is detected is a constant amount in the above-described embodiment, but the change amount can be variable. For example, when the amount of inappropriate temperature rise or the rising gradient of the electric brake is large, the brake release position is changed by a larger amount than when it is small.

It is a figure showing roughly the electric brake equipment which is one example of the present invention. It is a figure which shows notionally the structure of ROM which is a component of the computer of the controller of the electric brake device shown in FIG. It is a figure which shows notionally the structure of RAM which is a component of the computer of the controller of the electric brake device shown in FIG. It is a flowchart showing the control program memorize | stored in ROM of the electric brake device shown in FIG. It is a flowchart showing the detail of S3 of the control program shown in FIG. It is a flowchart showing the detail of S9 of the control program shown in FIG. It is a flowchart showing the detail of S14 of the control program shown in FIG.

Explanation of symbols

14: Controller 16: Electric motor 22: Brake rotor 30: Caliper 40: Motion conversion mechanism 50: Computer 64: Resistance value detection device 66: Braking force detection device 52: ROM 54: RAM 70: Control program memory 72: Resistance / temperature Relationship map

Claims (2)

An electric brake incorporating a caliper straddling the disc-shaped brake rotor, an electric motor, and a motion conversion mechanism that converts the rotation of the electric motor into a motion that presses the friction member against the brake rotor;
A temperature detecting device for detecting the temperature of the electric brake;
A motor control device that controls the electric motor, and the motor control device is in a state where the brake detection state continues for a set time or more and the temperature detected by the temperature detection device exceeds the set temperature. An electric brake device comprising a drag reducing portion for rotating the electric motor in a brake releasing direction. An electric brake incorporating a caliper straddling the disc-shaped brake rotor, an electric motor, and a motion conversion mechanism that converts the rotation of the electric motor into a motion that presses the friction member against the brake rotor;
An inappropriate temperature rise detection device for detecting an inappropriate temperature rise of the electric brake;
A motor control device for controlling the electric motor, and when the motor control device detects an inappropriate temperature rise by the inappropriate temperature rise detection device, An electric brake device comprising: a brake release position changing unit for changing a certain brake release position in a brake release direction further than a brake release position so far.

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