JP2013180676A - Braking force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control braking force for each cause of irregularities on a disk rotor, and to reduce judder during braking to be caused by the irregularities, thereby improving driving feeling.SOLUTION: A braking force control device estimates an irregular surface condition of a disk rotor 106, detects a temperature of a brake pad 108, relatively reduces a pressing force in a part of the surface of the disk rotor 106, where an area in contact with the brake pad 108 is protruded higher than a predetermined position, when the temperature of the brake pad 108 is equal to or higher than a predetermined temperature, and relatively increases the pressing force in a part where the contact area is recessed lower than the reference position. When the temperature of the brake pad 108 is less than the predetermined temperature, the controller relatively increases the pressing force in a part where the area in contact with the brake pad 108 is protruded higher than the reference position.

Description

  The present invention relates to a braking force control device that controls a braking force of a vehicle braking device that brakes a vehicle.

  Conventionally, in a vehicle braking device (brake mechanism) that brakes a vehicle by pressing a brake pad against the surface of a disk rotor that rotates with a tire, due to aging deterioration, friction with the brake pad, heat generated during braking, etc. It is known that irregularities occur on the surface. Due to the unevenness, the distance between the disk rotor and the brake pad varies during one rotation of the disk rotor. Specifically, the distance between the disc rotor and the brake pad is increased in the convex portion, and the distance between the disc rotor and the brake pad is decreased in the concave portion. As a result, even if the brake operation is performed with a constant force, the pressing force generated between the disk rotor and the brake pad changes during the rotation of the disk rotor, causing judder and feeling during operation. There was a problem of getting worse.

  In order to solve such a problem, for example, in Patent Document 1 below, a disc rotor thickness difference is detected, and a brake pad is applied to a portion where the disc rotor is thicker than a portion where the disc rotor is thin with a large pressing force. Make contact. Thereby, the thick part of a disk rotor is ground and the thickness difference of a disk rotor is reduced.

JP 2001-130393 A

  Of the irregularities generated on the disk rotor surface, those caused by aging and friction with the brake pads are steady deformations, whereas those caused by heat generated during braking are temporary. In the above-described prior art, the disk rotor is ground regardless of the cause of such unevenness, so that the portion where the temporary deformation is caused by heat may be promoted by changing the thickness difference of the disk rotor. There is a problem that there is.

  The present invention has been made in view of the above-described problems of the prior art, performs appropriate braking force control for each cause of occurrence of the disk rotor, reduces judder during braking caused by the unevenness, and operates. The purpose is to improve the feeling inside.

  In order to solve the above-described problems and achieve the object, a braking force control device according to the present invention controls the braking force of a vehicle braking device that presses a brake pad against the surface of a disk rotor that rotates together with a tire to brake the vehicle. A braking force control device that estimates an uneven state of the surface of the disk rotor, a detection unit that detects a temperature of the vehicle braking device, an estimation result by the estimation unit, and a detection result by the detection unit Control means for controlling the pressing force of the brake pad to the disk rotor based on the control means, and the control means, when the temperature of the vehicle braking means is equal to or higher than a predetermined temperature, the surface of the disk rotor Among them, the pressing force is relatively reduced at a location where the contact range with the brake pad is more convex than a predetermined reference position. When the pressing force is relatively increased at a location where the contact range is recessed from the reference position, and the temperature of the vehicle braking means is less than a predetermined temperature, the brake pad on the surface of the disc rotor The pressing force is relatively increased at a location where the contact range is more convex than a predetermined reference position.

  According to the first aspect of the present invention, the uneven state of the surface of the disk rotor is estimated, the temperature of the vehicle braking device is detected, and the pressing force of the brake pad is controlled by a different method for each temperature. Specifically, when the temperature of the vehicle braking device is equal to or higher than a predetermined temperature, the pressing force is relatively small at a location where the contact range with the brake pad is more convex than the predetermined reference position on the surface of the disk rotor. Then, the pressing force is relatively increased at a location where the contact range is more concave than the reference position. As a result, a constant braking force can be obtained regardless of the unevenness of the disk rotor surface, and judder can be reduced. On the other hand, when the temperature of the vehicle braking device is lower than the predetermined temperature, the pressing force is relatively increased at the convex portion. Thereby, the convex part of the disk rotor surface can be ground, the thickness of the disk rotor can be made constant, and judder can be reduced.

  According to the invention of claim 2, since the amount of brake operation by the driver is detected and control is not performed when the amount of brake operation is less than or equal to a predetermined value, there is a possibility that judder that can be detected by the passenger is generated. Only when there is, can control to reduce judder.

  According to the invention of claim 3, a change in the pressing force of the disc rotor accompanying the driver's brake operation is detected, and the disc rotor is determined from the difference between the pressing force predicted from the operation amount of the brake operation and the detected pressing force. Therefore, the uneven state of the disk rotor can be accurately estimated, and judder during braking can be further reduced.

It is explanatory drawing which shows the structure of the vehicle 100 to which the braking force control apparatus concerning embodiment is applied. It is explanatory drawing which shows the detail of braking force control by the control part 143. FIG. It is a graph which shows an example of the relationship between the gain value which calculates additional pressing force, and temperature. 5 is a flowchart showing a procedure of a braking force control process by a braking force control device 140. It is a figure which shows an example of a structure of an electrically driven brake.

  Exemplary embodiments of a braking force control apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following embodiment, an example in which the braking force control device according to the present invention is applied to a vehicle 100 that is an electric automobile will be described.

(Embodiment)
FIG. 1 is an explanatory diagram illustrating a configuration of a vehicle 100 to which the braking force control device according to the embodiment is applied. In FIG. 1, illustrations of components that are not related to the application of the braking force control device to the vehicle 100 are omitted. A vehicle 100 is an electric vehicle, and travels by rotating a tire 101 by driving a motor 102 with electric power stored in a battery (not shown).

  The rotation of the tire 101 is braked by the operation of the brake pedal 103 by the driver. When the brake pedal 103 is depressed by the driver, the piston in the master cylinder 104 is driven by the depression force, and the brake fluid filled in the master cylinder 104 is pushed out. The pushed brake fluid is transmitted to the brake caliper 107 through the brake pipe 105. Note that the depression force on the brake pedal 103 is measured by a pedal sensor (not shown) and is output to a braking force control device 140 and an EV-ECU 130 described later.

  When the stepping force on the brake pedal 103 is transmitted to the master cylinder 104, the pressure necessary for braking the vehicle 100 is obtained by amplifying the stepping force by the brake booster 110. The interior of the brake booster 110 is divided into two compartments: an air chamber on the brake pedal 103 side and a negative pressure chamber on the master cylinder 104 side. Due to the pressure difference between the two sections, a force is generated from the brake pedal 103 side toward the master cylinder 104 side, and assists in pushing the piston in the master cylinder 104. The negative pressure in the negative pressure chamber of the brake booster 110 is generated by the electric vacuum pump 111.

  The motor rotation speed sensor 121 measures the rotation speed of the motor 102 per unit time. The wheel speed sensor 122 is provided in each tire 101 and measures the rotational speed of each tire 101.

  The brake caliper 107 is provided with a brake pad 108 (see FIG. 2) and a piston. In the brake caliper 107, the piston is driven by the action of the pressure transmitted to the brake fluid and presses the brake pad 108 against the disc rotor 106. Then, the friction between the disc rotor 106 and the brake pad 108 releases the kinetic energy of the tire 101 as heat energy into the air, the rotation of the tire 101 stops, and the vehicle 100 stops.

  Here, the pressing force of the brake pad 108 against the disc rotor 106 is controlled by the braking force control device 140. The surface of the disk rotor 106 is uneven due to aging, friction with the brake pads, heat generated during braking, or the like. Due to the unevenness, the distance between the disk rotor 106 and the brake pad 108 varies during one rotation of the disk rotor. Specifically, the distance between the disc rotor 106 and the brake pad 108 is small at the convex portion, and the distance between the disc rotor 106 and the brake pad 108 is large at the concave portion. As a result, even if the brake operation is performed with a constant force, the pressing force generated between the disc rotor 106 and the brake pad 108 changes to generate judder, which deteriorates the feeling during operation.

  In order to solve such a problem, the braking force control device 140 estimates the uneven state of the surface of the disc rotor 106, detects the temperature of the brake pad 108 (vehicle braking device), and based on the estimation result. The pressing force of the brake pad 108 to the disc rotor 106 is controlled. More specifically, when the brake pad 108 is at a normal temperature (less than a predetermined temperature), the pressing force is applied to a portion of the surface of the disc rotor 106 where the contact range with the brake pad 108 is more convex than a predetermined reference position. Is relatively large. On the other hand, when the brake pad 108 is hot (predetermined temperature or higher), the pressing force is relatively applied at a portion of the surface of the disc rotor 106 where the contact range with the brake pad 108 is more convex than the predetermined reference position. The pressure is relatively increased at a location where the contact range is more concave than the reference position.

  This is because the unevenness generated on the surface of the disk rotor 106 due to aging and friction with the brake pad 108 is a steady deformation, so the pressing force of the brake pad 108 is increased and the convex part is ground. At the same time, since the heat caused by braking is temporary, it is necessary to reduce the judder during braking by changing the pressing force of the brake pad 108 along the unevenness without grinding. is there. The braking force control device 140 can more reliably reduce judder during braking by controlling the pressing force of the brake pad 108 in accordance with the cause of unevenness on the surface of the disk rotor 106.

  The braking force control device 140 includes a CPU, a ROM that stores and stores a control program, a RAM as an operation area of the control program, an EEPROM that holds various data in a rewritable manner, an interface unit that interfaces with peripheral circuits, and the like. Consists of including. The braking force control device 140 is connected to each part of the vehicle 100 via an interface part, exchanges information with each part, and controls each part.

  Moreover, the braking force control apparatus 140 implement | achieves the estimation part 141, the detection part 142, the control part 143, and the detection part 144, when the said CPU runs the said control program. In this embodiment, the braking force control device 140 and the EV-ECU 130 are configured separately, but the braking force control device 140 may be realized as a function of the EV-ECU 130.

  The estimation unit 141 estimates the uneven state of the surface of the disk rotor 106. Specifically, the estimation unit 141 detects a change in the pressing force of the brake pad 108 accompanying the driver's brake operation, and based on the difference between the pressing force predicted from the operation amount of the brake operation and the detected pressing force. Estimate unevenness. In the present embodiment, the surface of the disk rotor 106 refers to the surface on the side where the contact surface between the disk rotor 106 and the brake pad 108 is present, and the uneven state of the surface of the disk rotor 106 refers to the surface of the disk rotor 106. The difference of the thickness on the same periphery used as the contact surface with the brake pad 108 is shown.

  More specifically, the estimation unit 141 first estimates the current rotational position of the disc rotor 106 (for example, the rotational angle from the reference position) from the wheel speed information output from the wheel speed sensor 122. Next, the estimation unit 141 calculates the pressing force requested by the driver from the depression force (brake operation amount) to the brake pedal 103 output from the pedal sensor. The brake pad 108 is provided with a sensor (pressing force sensor) for measuring the pressing force against the disc rotor 106, and the estimation unit 141 outputs an output value (actually generated pressing value) from the pressing force sensor, Compare the pressing force required by the driver.

  When the contact portion between the brake pad 108 and the disc rotor 106 is thicker (convex portion) than the other portions, the distance between the disc rotor 106 and the brake pad 108 is reduced, and the actually generated pressure value is determined by the driving It becomes larger than the pressing force required by the person or the pressing force in other parts. On the other hand, when the contact portion between the brake pad 108 and the disc rotor 106 is thinner than the other portion (concave portion), the distance between the disc rotor 106 and the brake pad 108 is increased, and the actually generated pressure value is It becomes smaller than the pressing force required by the driver or other portions. The estimating unit 141 records the estimated uneven state and the rotational position of the disk rotor 106 in association with each other, and predicts the uneven state for one rotation of the disk rotor 106.

  The detection unit 142 detects the temperature of the brake pad 108. The detection unit 142 detects the temperature of the brake pad 108 by acquiring an output value from a temperature sensor provided on the brake pad 108. Since the brake pad 108 and the disk rotor 106 are in contact with each other during braking, the temperature state of the disk rotor 106 can be estimated from the temperature state of the brake pad 108. In the present embodiment, the detection unit 142 detects the temperature of the brake pad 108, but may detect the temperature of the disc rotor 106. In this embodiment, the output value from the temperature sensor provided on the brake pad 108 is acquired. However, the temperature of the brake pad 108 is estimated using various information instead of directly detecting the temperature. You may make it do. For example, a method of estimating the temperature of the brake pad 108 from the required braking force or its time can be considered.

  The control unit 143 controls the pressing force of the brake pad 108 to the disc rotor 106 based on the estimation result by the estimation unit 141 and the detection result by the detection unit 142. As described above, when the temperature of the brake pad 108 is equal to or higher than the predetermined temperature, the control unit 143 is a portion of the surface of the disc rotor 106 where the contact range with the brake pad 108 is more convex than the predetermined reference position. The pressing force is relatively decreased, and the pressing force is relatively increased at a location where the contact range is in a concave state with respect to the reference position. As a result, a constant braking force can be obtained regardless of the irregularities on the surface of the disk rotor 106, and judder can be reduced. On the other hand, when the temperature of the brake pad 108 is lower than the predetermined temperature, the pressing force is relatively increased at a location where the contact range with the brake pad 108 is more convex than the predetermined reference position. Thereby, the convex part of the disk rotor 106 surface can be ground, the thickness of the disk rotor 106 can be made constant, and judder can be reduced.

  FIG. 2 is an explanatory diagram showing details of the braking force control by the control unit 143. The upper part of FIG. 2 shows the rotational position of the disk rotor 106, and the point S is a reference point. FIG. 2 shows a diagram in which the disc rotor 106 is rotated by 90 degrees with the reference point S at the same angle as the center position of the brake pad 108 (position A and position D) as the reference position.

  The middle part of FIG. 2 shows the uneven state of the disk rotor 106 at the contact position with the brake pad 108. In FIG. 2, the uneven state of the disc rotor 106 is shown as a distance y from a reference point provided on the brake caliper 107 side (see the upper right diagram in FIG. 2). For this reason, the distance between the disc rotor 106 and the brake pad 108 is large in the concave portion, and the distance between the disc rotor 106 and the brake pad 108 is small in the convex portion. In FIG. 2, the distance at the position where the rotation angle of the disk rotor 106 is 0 is 0 (reference position), and a positive value is obtained at a location where the distance is large (concave portion), and a negative value is provided at a location where the distance is small (convex portion). The value is taken.

  The lower part of FIG. 2 shows the additional pressing force of the brake pad 108. When the temperature of the brake pad 108 is equal to or higher than the predetermined temperature, the solid line indicates that the temperature of the brake pad 108 is lower than the predetermined temperature. Is the case. The additional pressing force is obtained, for example, by multiplying the value of the uneven state of the disk rotor 106 shown in the middle stage by a gain value depending on temperature.

  FIG. 3 is a graph showing an example of the relationship between the gain value for calculating the additional pressing force and the temperature. In FIG. 3, the vertical axis represents the gain value, and the horizontal axis represents the temperature T of the brake pad. When the temperature T is lower than the first predetermined temperature T1, the gain value is a positive value, and when the temperature T is equal to or higher than the second predetermined temperature T2, the gain value is a negative value. Further, when the temperature T is equal to or higher than T1 and lower than T2, the gain value is set to 0. This is to avoid a sudden change in the control amount due to a temperature change.

  When the temperature of the brake pad 108 is lower than a predetermined temperature (T <T1), the additional pressing force is obtained by multiplying the value of the uneven state of the disk rotor 106 shown in the middle of FIG. 2 by a negative gain value. As described above, since the distance between the disc rotor 106 and the brake pad 108 is a positive value in the concave portion and a negative value in the convex portion, the additional pressing force in the concave portion is a negative value, and the additional pressing force in the convex portion is Takes a positive value (lower dotted line in FIG. 2). Thereby, in the convex part, a pressing force equal to or more than the required pressing force corresponding to the brake operation amount of the driver is applied, the surface of the disk rotor 106 is ground, and the thickness of the disk rotor 106 can be brought close to a constant value. .

  On the other hand, when the temperature of the brake pad 108 is equal to or higher than the predetermined temperature (T> T2), the additional pressing force is obtained by multiplying the value of the uneven state of the disk rotor 106 shown in the middle of FIG. 2 by a positive gain value. . As described above, since the distance between the disc rotor 106 and the brake pad 108 takes a positive value in the concave portion and a negative value in the convex portion, the additional pressing force in the concave portion is a positive value, and the additional pressing force in the convex portion is It takes a negative value (lower solid line in FIG. 2). The control unit 143 adds the additional pressing force corresponding to the uneven state of the disk rotor 106 to the required pressing force corresponding to the brake operation amount of the driver, thereby canceling the variation in the pressing force due to the unevenness of the disk rotor 106. To do.

  Returning to the description of FIG. 1, the detection unit 144 detects the amount of brake operation by the driver. When the brake operation amount detected by the detection unit 144 is equal to or less than the predetermined amount, the control unit 143 does not control the pressing force of the brake pad 108. This is because judder does not occur when the amount of brake operation is small, or it is a judder that does not bother the passenger. Further, when the amount of brake operation detected by the detection unit 144 is equal to or less than a predetermined amount, the estimation unit 141 also does not estimate the uneven state. This is because it is necessary to apply a certain amount of pressing force in order to estimate the uneven state of the disk rotor 106 by the method in the present embodiment.

  FIG. 4 is a flowchart showing the procedure of the braking force control process by the braking force control device 140. In the flowchart of FIG. 4, the braking force control device 140 waits until the vehicle starts running (step S301: No loop), and when the vehicle starts running (step S301: Yes), the estimation unit 141 Wheel speed information is acquired from the wheel speed sensor 122 (step S302), and the wheel rotation angle from the reference point is calculated (step S303).

  Next, the braking force control device 140 acquires the depression force (pedal stroke) from the pedal sensor to the brake pedal 103 by the detection unit 144 (step S304), and calculates the required pressing force requested by the driver (step S304). S305), it is determined whether the required pressing force is a predetermined value or more (step S306). When the required pressing force is not equal to or greater than the predetermined value (step S306: No), the braking force control device 140 proceeds to step S314 and sets the additional pressing force to 0 and performs the subsequent processing.

  On the other hand, when the required pressing force is equal to or greater than the predetermined value (step S306: Yes), the braking force control device 140 determines whether or not the uneven state on the surface of the disk rotor 106 has been estimated by the estimation unit 141 (step S307). . Note that the estimation of the uneven state by the estimation unit 141 may be performed, for example, every time the vehicle 100 travels, or may be performed periodically every predetermined period. When the uneven state has been estimated (step S307: Yes), the control unit 143 reads uneven information indicating the uneven state of the disk rotor 106 (step S308). Next, the temperature of the brake pad 108 is detected by the detection unit 142 (step S309), and the gain value is determined based on the temperature of the brake pad 108 (step S310). Then, the additional pressing force at each rotation angle is calculated based on the determined gain value (step S311), and the process proceeds to step S318.

  On the other hand, in step S307, when the uneven state on the surface of the disk rotor 106 has not been estimated (step S307: No), the process proceeds to step S312 and the unevenness state is estimated by the estimation unit 141. The estimation unit 141 acquires current pressing force information from the pressing force sensor provided on the brake pad 108 (step S312), and calculates the disc from the difference between the requested pressing force calculated in step S305 and the current pressing force. The uneven state on the surface of the rotor 106 is estimated (step S313).

  For example, when the required pressing force—the current pressing force is positive, the estimating unit 141 is smaller than the required pressing force, that is, the distance between the brake pad 108 and the disc rotor 106 is predicted. It is considered to be a large recess. Further, when the required pressing force minus the current pressing force is negative, the current pressing force is a convex portion that is larger than the required pressing force, that is, the distance between the brake pad 108 and the disc rotor 106 is smaller than the predicted distance. it is conceivable that.

  The estimation unit 141 records the uneven state estimated in step S311 in association with the rotation angle information of the wheels (step S314). Until the recording of the concavo-convex state for one rotation is completed (step S315: No), the process proceeds to step S317, and the subsequent processing is performed. When the recording of the uneven state for one rotation is completed (step S315: Yes), the estimating unit 141 completes the recording of the uneven state (step S316). The control unit 143 sets the additional pressing amount to 0 until the estimation of the uneven state by the estimation unit 141 is completed (step S317).

  The control unit 143 calculates the total pressing amount by the required pressing amount + the additional pressing amount (step S318), and controls to press the brake pad 108 against the disc rotor 106 with a force corresponding to the total pressing amount (step S319). . Until the vehicle 100 finishes traveling (step S320: No), the braking force control device 140 returns to step S302 and repeats the subsequent processing. And if the vehicle 100 complete | finishes driving | running | working (step S320: Yes), the process by this flowchart will be complete | finished.

  In the present embodiment, the brake of the vehicle 100 has been described as a hydraulic brake, but the braking force control apparatus according to the present invention may be applied to an electric brake using an electric caliper. The electric brake is a brake system that obtains a braking force by operating an electric motor or the like mounted on a caliper and pressing a brake pad against a rotor. In the electric brake, the driver's operation is detected by a pedal stroke sensor, and the electric motor is controlled based on the operation amount (brake-by-wire).

  FIG. 5 is a diagram illustrating an example of the configuration of the electric brake. The electric brake device shown in FIG. 5 is provided on each of the four wheels of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, and a motor drive current corresponding to the target braking torque of each wheel is applied to the electric motor of each wheel. Sent. As shown in the figure, a brake rotor 1 that rotates together with wheels is provided, and the brake rotor 1 is pressed by a pair of brake pads 2 to generate braking torque and deceleration torque by frictional force. That is, the caliper 3 is supported on the vehicle body side so as to freely reciprocate (in the horizontal direction in the figure), and the electric motor 4 that is an electric actuator is fixed to the caliper 3. A piston 5 is slidably fitted to the caliper 3.

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

  For example, when the drive shaft 7 of the electric motor 4 rotates in the forward direction, the piston 5 is driven in the left direction in the figure, and the brake pad 2 attached to the piston 5 presses the brake rotor 1 and at the same time the caliper 3 is counteracted. The brake rotor 1 is pressed by the pair of brake pads 2 by sliding in the right direction in the figure by force. As a result, braking torque and deceleration torque are generated. For example, when the drive shaft 7 of the electric motor 4 rotates in the reverse direction, the pair of brake pads 2 are separated from the brake rotor 1. Thereby, braking torque and deceleration torque are released.

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

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

  Moreover, the uneven | corrugated state estimation method demonstrated in this Embodiment is an example, and you may estimate an uneven | corrugated state by another method. For example, instead of the output value of the pressing force sensor described above, the uneven state may be estimated using the rotation angle of the electric motor mounted on the caliper of the electric brake and the fluctuation of the current value flowing through the electric motor. In addition, the rotor unevenness is used by estimation this time, but the rotor unevenness may be directly detected using a laser distance meter or the like.

  As described above, the braking force control device 140 according to the embodiment estimates the uneven state of the surface of the disc rotor 106, detects the temperature of the brake pad 108, and the temperature of the brake pad 108 is equal to or higher than a predetermined temperature. In this case, the pressing force is relatively reduced at a portion of the surface of the disc rotor 106 where the contact range with the brake pad 108 is more convex than the predetermined reference position, and the contact range is more concave than the reference position. Make the pressing force relatively large at the point. As a result, a constant braking force can be obtained regardless of the irregularities on the surface of the disk rotor 106, and judder can be reduced. On the other hand, when the temperature of the brake pad 108 is lower than the predetermined temperature, the pressing force is relatively increased at a location where the contact range with the brake pad 108 is more convex than the predetermined reference position. Thereby, the convex part of the disk rotor 106 surface can be ground, the thickness of the disk rotor 106 can be made constant, and judder can be reduced.

  In addition, the braking force control device 140 detects the amount of brake operation by the driver and does not perform control when the amount of brake operation is equal to or less than a predetermined value. Therefore, there is a possibility that judder that can be detected by the passenger may occur. Only when there is, can control to reduce judder.

  Further, the braking force control device 140 detects a change in the pressing force of the disc rotor 106 accompanying the driver's brake operation, and determines the disc from the difference between the pressing force predicted from the operation amount of the brake operation and the detected pressing force. Since the uneven state of the rotor 106 is estimated, the uneven state of the disk rotor 106 can be accurately estimated, and judder during braking can be further reduced.

  DESCRIPTION OF SYMBOLS 100 ... Vehicle, 101 ... Tire, 102 ... Motor, 103 ... Brake pedal, 104 ... Master cylinder, 105 ... Brake piping, 106 ... Disc rotor, 107 ... Brake caliper, 108 ... Brake pad 110 …… Brake booster, 111 …… Electric vacuum pump, 121 …… Motor speed sensor, 122 …… Wheel speed sensor, 130 …… EV-ECU, 140 ……, Braking force control device, 141 …… Estimating unit , 142... Detection unit, 143... Control unit, 144.

Claims (3)

A braking force control device that controls a braking force of a vehicle braking device that presses a brake pad against a surface of a disk rotor that rotates together with a tire to brake the vehicle,
Estimating means for estimating the uneven state of the surface of the disk rotor;
Detecting means for detecting the temperature of the vehicle braking device;
Control means for controlling the pressing force of the brake pad to the disk rotor based on the estimation result by the estimation means and the detection result by the detection means,
The control means includes
When the temperature of the vehicle braking means is equal to or higher than a predetermined temperature, the pressing force is relatively reduced at a portion of the surface of the disk rotor where the contact range with the brake pad is more convex than a predetermined reference position. In addition, the pressing force is relatively increased at a location where the contact range is in a concave state with respect to the reference position,
When the temperature of the vehicle braking means is lower than a predetermined temperature, the pressing force is relatively increased at a portion of the surface of the disk rotor where the contact range with the brake pad is more convex than a predetermined reference position. A braking force control device. It further comprises detection means for detecting the amount of brake operation by the driver,
2. The braking force control apparatus according to claim 1, wherein the control unit does not perform the control when the brake operation amount is equal to or less than a predetermined value.   The estimation means detects a change in the pressing force of the brake pad that accompanies the driver's brake operation, and calculates a difference between the pressing force predicted from the operation amount of the brake operation and the detected pressing force. The braking force control device according to claim 1, wherein the uneven state is estimated.

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