JP2006103630A - Brake control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular braking control device capable of jointly using a regenerative brake and a friction brake for braking each wheel, and preventing degradation of the braking force and generation of the vibration and squeaking attributable to the rust by removing the rust generated on a disk rotor in an early stage. <P>SOLUTION: The vehicular braking control device has an in-wheel motor and a friction brake on each wheel, and jointly uses the regenerative braking force by the in-wheel motor and the friction braking force by the friction brake in the braking mode. The pressing force of the friction brake against a disk rotor is detected, the torque to the wheels is obtained from the current of the in-wheel motor (Step 12), generation of the rust on the disk rotor is determined (Step 13) based on the pressing force and the torque detected in Step 12, provision of the braking force by the regenerative brake is stopped when it is determined in Step 13 that the rust is generated on the disk rotor, and the braking is preferentially performed by the friction brake (Step 14). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle braking control device, and more particularly to a vehicle braking control device capable of using both a regenerative brake and a friction brake for braking each wheel.

  2. Description of the Related Art In recent years, electric vehicles that run by driving a motor (motor) with electric power charged in a battery as a non-polluting vehicle and rotating wheels have attracted attention. In addition, as a braking (braking) means for the electric vehicle, an electric braking method and a friction braking method are used in combination. In addition, as a motor, an in-wheel motor that can perform drive control for each wheel and can be made compact is drawing attention. This in-wheel motor is configured such that a motor is disposed in the wheel of each wheel.

  Here, the electric braking method is a method of braking the wheel through the motor by converting the kinetic energy of the motor into electric energy (electric power) and returning it to the battery (hereinafter referred to as this electric braking method). The braking means is called regenerative braking). In addition, the friction braking method is a braking method that has been generally adopted conventionally, in which a friction material is pressed against a disk rotor attached to a wheel by applying hydraulic pressure to a cylinder, and the wheel is braked directly. There is (hereinafter, this friction braking means is called a friction brake).

  As is well known, a disk brake generally used as a friction brake drives a friction material arranged with a disk rotor in a caliper by a piston, and presses the friction material against the disk rotor to apply a braking force. It is configured to generate. Since this disc rotor is usually made of an iron-based material, when the disc rotor has not been used for a long period of time, or when the disc rotor adheres to water due to rain, the disc rotor rusts. May occur.

As described above, when rust is generated in the disc rotor, abnormal noise or vibration is generated, or a reduction in braking force is generated. As a method for preventing these occurrences, for example, as disclosed in Patent Document 1, when abnormal noise or the like occurs, the friction brake is prioritized and the regenerative brake without the abnormal noise is prioritized. It is possible to use it.
Japanese Patent Publication No. 6-24908

  However, the method disclosed in Patent Document 1 is an effective method when abnormal noise or the like occurs due to reasons other than rust, but when abnormal noise or the like occurs due to rust. The following problems occur.

  That is, when rust is generated in the disk rotor, if the rust is left as it is, the amount of rust generated increases, and the braking performance and vibration of the friction brake increase accordingly. Further, since the disk rotor turns reddish brown, the appearance is also poor. Furthermore, even if an attempt is made to remove a large amount of rust in this way, there is a problem that the removal work is difficult and the rust cannot be removed by a simple rust removal treatment.

  The present invention has been made in view of the above points, and provides a vehicle braking control device capable of preventing a reduction in braking force and occurrence of vibration and squeal due to rust by removing a disk rotor at an early stage. For the purpose.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

The invention according to claim 1
Each wheel has an in-wheel motor and a friction brake.
A braking control device for a vehicle that uses both a regenerative braking force generated by the in-wheel motor during braking and a friction braking force generated by pressing the disk rotor provided on the wheel by the friction brake,
A pressing force detecting means for detecting a pressing force of the friction brake against the disk rotor;
From the current value of the in-wheel motor, torque detection means for obtaining torque for the wheel;
Rust occurrence determination means for determining the occurrence of rust on the disk rotor based on the pressing force detected by the pressing force detection means and the torque obtained by the torque detection means;
When the rust occurrence determining means determines that rust is generated on the disk rotor, braking selection means for stopping application of the braking force by the in-wheel motor at the time of braking and performing braking by the friction brake is provided. It is characterized by having.

  According to the above invention, the rust occurrence determination means determines the occurrence of rust of the disk rotor based on the pressing force detected by the pressing force detection means and the torque required by the torque detection means, and rust is generated. When it is determined, the braking selection means stops applying the braking force by the in-wheel motor, and only the braking by the friction brake is performed. Thereby, since the rust generated in the disc rotor is removed by the friction brake, it is possible to prevent a reduction in braking force, vibration and squeal due to the rust. Moreover, since rust generated in the disk rotor is removed in a short time after the rust is generated, the rust can be removed easily and reliably.

The invention according to claim 2
The vehicle braking control device according to claim 1,
The rust occurrence determination means has storage means for storing the pressing force and the torque, and the pressing force and torque detected this time with respect to the pressing force and torque before the previous time stored in the storage means. It is determined that rust has occurred in the disk rotor when the values of are different from each other by a predetermined value or more.

  According to the above invention, the determination process is performed easily and reliably because the occurrence of rust is determined by comparing the previous pressing force and torque stored in the storage means with the detected pressing force and torque. It can be carried out.

The invention according to claim 3
The braking control device according to claim 1 or 2,
The rust occurrence determination means detects the occurrence of rust for each of the plurality of disk rotors,
The brake selection means cancels the control of braking by the friction brake in preference to the braking by the in-wheel motor when it is confirmed that no rust has occurred in all the disk rotors. It is.

  According to the above invention, since rust is generated on all of the plurality of wheels and the configuration returns to cooperative regeneration by the in-wheel motor and the friction brake, rust remains on any of the plurality of wheels. This makes it possible to cause each brake to perform uniform braking without bias.

The invention according to claim 4
The braking control device according to any one of claims 1 to 3,
Vehicle state detection means for detecting that the vehicle is in a state where water droplets are likely to adhere to the disk rotor;
The rust occurrence determination means executes a process for determining the occurrence of rust on the disk rotor when the vehicle state detection means determines that the vehicle is in a state where water droplets are likely to adhere to the disk rotor. It is a feature.

  According to the above-described invention, since the rust is detected when the vehicle is placed in a state where the rust is likely to be generated in the disc rotor, the time for performing the braking by the friction brake in preference to the in-wheel motor is shortened. It is possible to lengthen the normal cooperative braking time.

  As described above, according to the present invention, it is possible to prevent a decrease in braking force due to rust, vibration and squeal.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram of a vehicle braking control apparatus 10 (hereinafter simply referred to as a braking control apparatus 10) according to an embodiment of the present invention. In this embodiment, an in-wheel motor is incorporated in each of the right front wheel (FR), left front wheel (FL), right rear wheel (RR), and left rear wheel (RL) as a vehicle, and a disc brake as a friction brake. An electric vehicle provided with is described as an example. Hereinafter, a specific configuration of the braking control device 10 will be described.

  The master cylinder 20 is a tandem cylinder and includes two independent pressurizing chambers. A brake pedal 24 is connected to the master cylinder 20 via a vacuum booster 22. A vacuum pump 26 for supplying a negative pressure to the vacuum booster 22 is connected to the vacuum booster 22. The vacuum pump 26 is driven by a motor 28. In each pressurizing chamber of the master cylinder 20, equal hydraulic pressures are generated according to the depression operation of the brake pedal 24. Such hydraulic pressure is applied to the hydraulic pressure control circuit 30.

  The hydraulic pressure control circuit 30 applies pressure to the cylinders 40, 42, 44, and 46 of each wheel constituting the disc brake based on the hydraulic pressure applied from the master cylinder 20 and a command from the regenerative ECU 34 described later. The cylinders 40, 42, 44, and 46 are provided in order on the right front wheel (FR), the left front wheel (FL), the right rear wheel (RR), and the left rear wheel (RL), respectively. 50, 52 and 54 are driven. When the brake calipers 48, 50, 52, 54 are driven, the friction materials (brake pads) attached to the brake calipers 48, 50, 52, 54 are pressed toward the braking surfaces of the disk rotors 56, 58, 60, 62, respectively. A braking torque is applied to each wheel.

  Each cylinder 40, 42, 44, 46 is provided with a pressure sensor (not shown). The pressing force of the friction material against each disk rotor 56, 58, 60, 62 is detected by a pressure sensor provided in each cylinder 40, 42, 44, 46 and transmitted to the EV ECU 38. .

  In the present embodiment, a configuration in which the master cylinder 20 operated by the brake pedal 24 and the hydraulic pressure control circuit 30 are directly connected will be described as an example. However, the present invention relates to an operation system related to the operation of the brake pedal 24. The present invention can also be applied to a so-called by-wire structure in which the hydraulic control circuit 30 is separated.

  On the other hand, as described above, each of the wheels FR, FL, RR, and RL has an in-wheel motor. This in-wheel motor is configured to include gears 64, 66, 68, 70 and drive motors 72, 74, 76, 78. The drive motors 72, 74, 76, 78 are controlled by motor control devices 80, 82, 84, 86, respectively.

  The motor control devices 80, 82, 84 and 86 are configured to be supplied with power from a battery 88. Further, as will be described later, the motor control devices 80, 82, 84, and 86 have a function of charging the battery 88 with regenerative energy generated in the motor during braking of the vehicle as regenerative energy. The engine 90 is provided with a generator 92, and the battery 88 is charged with electric power generated by the generator 92 by the operation of the engine 90.

  The hydraulic pressure control device 30, the motor control devices 80 to 86, and the battery 88 described above are connected to the regenerative ECU 34. The regenerative ECU 34 is connected to an EVECU 38 that controls the entire vehicle. The regenerative ECU 34 receives information on the vehicle state from the EV ECU 38, and controls the braking device 10 of the electric vehicle based on the information. Although not shown in FIG. 1, the EV ECU 38 is connected to a wiper switch of a wiper that is operated in the rain and an ignition key switch that is operated when the vehicle is started.

  In the braking control device 10 described above, the vehicle is braked together with the hydraulic braking by the hydraulic control device 30 as described above, and the drive motors 72, 74, 76, 78 constituting the in-wheel motor, and the motor control for controlling this. This is also performed by regenerative braking with the devices 80, 82, 84, 86.

  In regenerative braking, back electromotive force generated in accordance with the inertial rotation of the drive motors 72, 74, 76, and 78 is supplied to the battery 88 as charging energy, that is, regenerative energy, and the regenerative energy is supplied to the battery 88. Thus, the torque generated in the disk rotors of the drive motors 72, 74, 76, 78 acts as a braking torque for each wheel. Hereinafter, the braking torque by regenerative braking is referred to as regenerative braking torque. This regenerative braking torque can be controlled by controlling the current values for the drive motors 72, 74, 76, 78.

  Specifically, the regenerative braking torque is controlled using a charging circuit that turns ON / OFF the charging current for the battery 88 provided in the motor control devices 80, 82, 84, 86. That is, in order to increase the regenerative braking torque, the ON time of the charging circuit is lengthened, and the time for supplying current from the drive motors 72, 74, 76, 78 to the battery 88 is lengthened. As a result, the kinetic energy of the drive motors 72, 74, 76, 78 is converted into electrical energy (current) and supplied to the battery 88, so that each wheel is driven via the drive motors 72, 74, 76, 78. The applied regenerative braking torque also increases.

  Conversely, to reduce the regenerative braking torque, the ON time of the charging circuit is shortened and the time for supplying current from the drive motors 72, 74, 76, 78 to the battery 88 is shortened. As a result, the conversion of the kinetic energy of the drive motors 72, 74, 76, and 78 into electrical energy (current) is reduced, and the regenerative braking torque for each wheel by the drive motors 72, 74, 76, and 78 is also reduced accordingly. To do.

  Next, the rust removal process for removing rust generated in the disk rotors 56, 58, 60, 62 performed by the EV ECU 38 will be described. FIG. 1 is a flowchart showing a rust removal process executed by the EV ECU 38. The rust removal process shown in the figure is performed, for example, when the vehicle is started.

  When the rust removal process shown in the figure is started, first, the EV ECU 38 determines in step 10 (step is abbreviated as S in the figure) whether or not there has been a wiper operation for one hour before stopping on the previous day. This determination is made based on whether or not the wiper switch is operated during the predetermined period. Therefore, if an affirmative determination is made in step 10, the vehicle is stopped for a predetermined period with rainwater adhering to the disk rotors 56, 58, 60, 62. It can be said that the possibility of rusting is great.

  If an affirmative determination (determination of YES) is made in step 10, the process proceeds to step 11 to determine whether or not the stop state of the vehicle is equal to or greater than the set number of days. Here, the set number of days is the number of days that the rust may occur in the disk rotors 56, 58, 60, and 62 when the vehicle is left unattended, and is determined by experiments. Therefore, if an affirmative determination is made in step 11, it can be said that there is a great possibility that rust will occur in the disk rotors 56, 58, 60 and 62.

  In this embodiment, when a negative determination (determination of NO) is made in step 10 and a negative determination is made in step 11, rust is generated in the disk rotors 56, 58, 60, and 62. It is determined that the possibility is low, and the rust removal process shown in this flowchart is terminated without performing the specific rust determination process and the rust removal process after Step 12.

On the other hand, if both steps 10 and 11 are affirmed, it is very likely that the disc rotors 56, 58, 60, 62 are rusted. For this reason, steps 10, 11 If both are determined to be affirmative, the process proceeds to step 12 to execute specific rust determination processing and rust removal processing.
As described above, in this embodiment, since the rust detection and the rust removal processing after step 12 are performed only when the vehicle is placed in a state where rust is likely to be generated in the disk rotors 56, 58, 60, 62, it will be described later. It is possible to shorten the execution time of braking by the disc brake (friction brake) in preference to the in-wheel motor described in step 14 and to combine ordinary cooperative braking (regenerative braking and friction braking in an optimal state). Control for braking) can be lengthened.

  In step 12, the EV ECU 38 confirms that the disk rotors 56, 58, 60, 62 are rotating (the vehicle is moving), and then controls the hydraulic pressure control circuit 30 to control each wheel. The cylinders 40, 42, 44, 46 are provided with hydraulic pressure, and the friction materials of the brake calipers 48, 50, 52, 54 are applied to the disk rotors 56, 58, 60, 62 regardless of the driver's operation of the brake pedal 24. Press on.

  The pressing force at this time is set to a strength that generates a braking torque that does not cause the driver to feel that braking is being performed. Further, as described above, each cylinder 40, 42, 44, 46 is provided with a pressure sensor (not shown), and the pressing force of the friction material is detected by this pressure sensor and transmitted to the EV ECU 38.

  At the same time, the motor control devices 80, 82, 84, and 86 output current values output from the drive motors 72, 74, 76, and 78 while the friction material is pressed against the disk rotors 56, 58, 60, and 62. Is detected, and this value is transmitted to the regeneration ECU 34. The regenerative ECU 34 calculates the torque generated in each wheel from the current value output from the drive motors 72, 74, 76, 78. The torque value calculated by the regenerative ECU 34 is transmitted to the EV ECU 38 and stored in a storage device provided in the EV ECU 38.

  In the following step 13, it is determined whether or not rust has occurred on the disk rotors 56, 58, 60, 62 of the wheels FR, FL, RR, RL. The determination of the occurrence of rust is made based on the torque value calculated from the pressing force of the friction material obtained in step 12 and the current value output from the drive motors 72, 74, 76, 78.

  Specifically, when rust is generated in the disk rotors 56, 58, 60, 62, vibration is generated between the friction material and the disk rotors 56, 58, 60, 62. This vibration is detected as a change in the pressing force of the friction material and a change in the torque value calculated from the current value. Further, when rust is generated in the disk rotors 56, 58, 60, 62, the frictional force between the friction material and the disk rotors 56, 58, 60, 62 decreases. Therefore, the occurrence of rust can be determined by detecting the change in the pressing force of the friction material and the change in the torque value calculated from the current value.

  Therefore, in order to detect rust, it is necessary to obtain in advance a torque value calculated from the pressing force and current value of the friction material in a state where rust is not generated (normal state). In this embodiment, in step 12, a torque value calculated from the pressing force and current value of the friction material is obtained every time the rust detection process is executed, and this is transmitted to the EVECU 38. At this time, the EV ECU 38 obtains an average value of the pressing force and the torque value (excluding the value determined to have generated rust) obtained in the previous rust removal process, and calculates the average pressing force and the average torque value. It is configured to memorize.

  Therefore, in step 13, it is determined whether or not the currently detected pressing force and torque value differ from the average pressing force and average torque value by a predetermined value or more. The predetermined value here is a change value that always occurs with respect to the average pressing force and the average torque value when rust is generated, excluding disturbance elements. This predetermined value is set empirically and experimentally.

  As described above, in this embodiment, since the rust generation is determined by comparing the previous pressing force and torque stored in the EV ECU 38 with the currently detected pressing force and torque, the determination process is easy and reliable. Can be done.

  If a negative determination is made in step 13, that is, if it is determined that no rust has occurred in any of the disk rotors 56, 58, 60, 62, it is not necessary to remove the rust, so the processing from step 14 onward is performed. The rust removal process shown in FIG.

  On the other hand, if an affirmative determination is made in step 13, that is, if it is determined that rust has occurred in all or part of the disk rotors 56, 58, 60, 62, the process proceeds to step 14. In step 14, when the driver operates the brake pedal 24, the EVECU 38 has priority over the in-wheel motor including the drive motors 72, 74, 76, 78, etc., and the cylinders 40, 42, 44, 46 and the brake caliper 48, A process using a disc brake composed of 50, 52, 54, etc. is performed. Accordingly, when an affirmative determination is made in step 13, the regenerative brake is temporarily stopped and the friction brake is preferentially used.

  As a result, the rust generated in the disk rotors 56, 58, 60, 62 is removed by the friction material being pressed by the cylinders 40, 42, 44, 46, so that the braking force is reduced due to the rust, and vibrations are also generated. The occurrence of noise and squealing can be reliably prevented. Moreover, since rust generated in the disk rotors 56, 58, 60, 62 is removed in a short time after the rust is generated, the rust can be easily removed in a short time. Moreover, by removing rust early, it is possible to prevent the appearance of the wheels from being deteriorated due to rust.

  In the subsequent step 15, the EV ECU 38 determines whether or not the rust of all the disk rotors 56, 58, 60, 62 has been removed. If it is determined that rust has not been completely removed (NO determination), the process returns to step 14 to continue the rust removal process. In contrast, if it is determined in step 15 that rust has been completely removed in all the disk rotors 56, 58, 60, 62 (YES determination), the rust removal process shown in FIG.

  As described above, in this embodiment, rust is generated on all of the plurality of wheels (disc rotors 56, 58, 60, 62), and then the in-wheel motor (regenerative brake) and the disc brake (friction brake) are used. Since it becomes the structure which returns to cooperative regeneration, rust does not remain in either, Therefore, uniform braking without a bias can be performed.

  In the above-described embodiment, the pressing force detecting means described in the claims corresponds to the pressure sensor and the hydraulic pressure control circuit 30 provided in the cylinders 40, 42, 44, 46. Further, the torque detection means described in the claims corresponds to the motor control devices 80, 82, 84, 86, the regenerative ECU 34, and the processing of step 12 in FIG. Moreover, the rust generation | occurrence | production determination means as described in a claim corresponds to step 13 shown in FIG. Further, the brake selection means described in the claims corresponds to step 14 shown in FIG.

  Next, various control processes that can be performed by the braking control device 10 described above will be described. First, with reference to FIG. 3 and FIG. 4, a brake assist process that can be performed by the above-described braking control device 10 will be described.

  FIG. 3A shows a sharing state between the braking force change from the start of braking to the stop of the vehicle and the regenerative braking force and the friction braking force when the normal driver performs the braking operation. As shown in the figure, when the braking force is increased to a predetermined value by the brake operation, control for maintaining the braking force at a certain position is performed thereafter for a certain period (a period indicated by an arrow T in the figure).

  However, it has been found that the configuration in which the predetermined braking force value is maintained after the braking force has increased to the predetermined value in this way gives the driver a feeling that the braking is not sufficiently performed. Therefore, in the present embodiment, as shown in FIG. 3A, the control for assisting the braking force (hereinafter referred to as braking force assist control) is performed with respect to the normal required braking force shown in FIG. It was.

  FIG. 4 is a flowchart of the braking force assist control. The braking force assist control shown in the figure is intended to improve the braking effectiveness feeling by increasing the regenerative braking force. Hereinafter, specific braking force assist control will be described.

  The braking force assist control is performed by the EV ECU 38 (see FIG. 1). When the control process shown in FIG. 4 is started, first, at step 20, it is determined whether the required braking force is smaller than the set value. The set value in step 20 is the minimum value of the driver-requested braking force at which the above-described so-called braking effectiveness is poor when the driver performs a braking operation.

  That is, when the driver's required braking force is small, braking is performed in a relatively short time, and the driver rarely feels that the braking effect is insufficient. On the other hand, when the driver's required braking force is small, braking is performed for a relatively long time, and the driver often feels that the braking effect is insufficient.

  Therefore, in step 20, a required braking force that the driver feels that the braking effect is insufficient is obtained in advance through experiments or the like, and this is used as a reference (set value). Therefore, when an affirmative determination is made in step 20, it is not necessary to assist the braking force, so that the braking force assist control is terminated without performing the braking force increase control (step 21).

  On the other hand, if a negative determination is made in step 20, that is, if it is determined that braking force assistance is required, the process proceeds to step 22 to determine whether or not the current running state of the vehicle is high speed. The This high speed determination can be made based on the output from the vehicle speed sensor.

  If an affirmative determination is made in step 22, that is, if it is determined that the vehicle is traveling at a high speed, the process proceeds to step 25 to perform dynamic braking. Here, the dynamic braking means supplying electric current to the drive motors 72, 74, 76, 78 by the regenerative ECU 34 and the motor control devices 80, 82, 84, 86 so that a driving force in the direction opposite to the rotational direction of the wheels is generated. Thus, a braking force is generated on each wheel. FIG. 3A shows a state where the braking force is assisted by the process of step 25. As shown in the figure, the power generation braking force is set to gradually increase. Thereby, the effect feeling with respect to the driver can be improved.

  On the other hand, if a negative determination is made in step 22, the process proceeds to step 23, and the EV ECU 38 determines whether or not the battery 88 is in a chargeable state. If a negative determination is made in step 23, that is, if the battery 88 is fully charged, the regenerative braking operation cannot be performed on the drive motors 72, 74, 76, 78. For this reason, the EV ECU 38 advances the process to step 25 and performs the above-described dynamic braking process. As a result, the power generation braking force can be assisted with respect to the driver requested braking force without imposing a burden on the battery 88, and the effect feeling to the driver can be improved.

  On the other hand, if an affirmative determination is made in step 23, that is, if the battery 88 is in a chargeable state, the process proceeds to step 24 where regenerative braking is performed. Therefore, also in this case, the regenerative braking force can be assisted with respect to the driver requested braking force, and the effect feeling to the driver can be improved.

  Next, the creep torque abnormal noise removal process among various control processes that can be performed by the braking control apparatus 10 will be described.

  In general, an automatic vehicle performs creep running in which the vehicle travels at an extremely low speed during idling. Further, in the case of an electric vehicle having an in-wheel motor, this creep travel is performed using drive motors 72, 74, 76, 78. It is also known that creeping noise due to vibration is generated when braking is performed by a friction brake during creep running. The object of the present embodiment is to prevent creep abnormal noise generated during creep running.

  5 and 6 are diagrams for explaining the creep torque abnormal noise removal processing. FIG. 5 shows the friction braking force and the creep torque (torque generated by the drive motors 72, 74, 76, and 78 during creep travel) for convenience of explanation. As shown in the figure, when braking is performed during creep traveling, the share of the friction braking force is set large at the start of braking, and after a predetermined time has elapsed, the friction material and the disk rotors 56, 58, 60 are set. , 62, the friction braking force is reduced at the time when creep torque abnormal noise is likely to occur, and the creep torque is reduced accordingly. Thereby, even if the friction braking force is reduced for each wheel, the driving force itself for each wheel is reduced, so that the speed of the vehicle can be reduced.

  FIG. 6 is a flowchart of the creep torque abnormal noise removal process performed based on the above principle. When the creep torque abnormal noise removal process shown in the figure is started, it is first determined in step 30 whether or not vibration is generated in the vehicle. This vehicle vibration can be detected by, for example, an acceleration sensor provided in the vehicle. In step 31, it is determined whether or not the speed of the vehicle is extremely low (creep running). This speed determination can be detected by a vehicle speed sensor. If a negative determination is made in steps 30 and 31, there is no possibility that creep torque noise will occur, so the present control process is terminated without performing the processes after step 32.

  On the other hand, if an affirmative determination is made in both steps 30 and 31, the process proceeds to step 32, where it is determined whether the generated vibration is only the front wheels. If it is determined in step 32 that vibration has occurred in the front wheels, the process proceeds to step 35 where creep driving is performed by the drive motors 72 and 74 corresponding to the front wheels (FR, FL), and the rear wheels (RR). , RL) is subjected to friction braking. As a result, braking can be performed without generating abnormal creep torque during creep running.

  If a negative determination is made in step 32, the process proceeds to step 33, where it is determined whether the generated vibration is only the rear wheel. If it is determined in step 33 that vibration has occurred in the rear wheels, the process proceeds to step 36, where creep driving is performed by the drive motors 76, 78 corresponding to the rear wheels (RR, RL), and the front wheels ( For FR, FL), friction braking is performed. As a result, braking can be performed without generating abnormal creep torque during creep running.

  On the other hand, if a negative determination is made in both steps 32 and 33, the process proceeds to step 34. The state in which the negative determination is made in both steps 32 and 33 is a state in which vibration is generated in all of the front wheels and the rear wheels, and thus there is a possibility that abnormal noises of creep torque may be generated in all the wheels. Therefore, if both the negative determinations are made in steps 32 and 33, the EV ECU 38 reduces the friction braking force by reducing the hydraulic pressure of the cylinders 40, 42, 44, and 46 in step 34, and accordingly the drive motor 72 is driven. , 74, 76, 78, the supply current value is reduced to reduce the creep torque. Accordingly, as described above with reference to FIG. 5, braking can be performed without generating abnormal creep torque during creep running.

FIG. 1 is a configuration diagram of a vehicle braking control apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing rust removal processing according to an embodiment of the present invention. FIG. 3 is a diagram for explaining brake assist processing that can be performed by the vehicle braking control apparatus according to the embodiment of the present invention. FIG. 4 is a flowchart showing a brake assist process that can be performed by the vehicle braking control apparatus according to the embodiment of the present invention. FIG. 5 is a view for explaining creep abnormal noise removal processing that can be performed by the vehicle braking control apparatus according to the embodiment of the present invention. FIG. 6 is a flowchart showing a creep noise removal process that can be performed by the vehicle braking control apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Braking control apparatus 20 Master cylinder 30 Fluid pressure control circuit 34 Regenerative ECU
38 EV ECU
40, 42, 44, 46 Hall cylinder 72, 74, 76, 78 Drive motor 80, 82, 84, 86 Motor controller 88 Battery

Claims (4)

Each wheel has an in-wheel motor and a friction brake.
A braking control device for a vehicle that uses both a regenerative braking force generated by the in-wheel motor during braking and a friction braking force generated by pressing the disk rotor provided on the wheel by the friction brake,
A pressing force detecting means for detecting a pressing force of the friction brake against the disk rotor;
From the current value of the in-wheel motor, torque detection means for obtaining torque for the wheel;
Rust occurrence determination means for determining the occurrence of rust on the disk rotor based on the pressing force detected by the pressing force detection means and the torque obtained by the torque detection means;
When the rust occurrence determining means determines that rust is generated on the disk rotor, braking selection means for stopping application of the braking force by the in-wheel motor at the time of braking and performing braking by the friction brake is provided. A braking control device for a vehicle, comprising: The vehicle braking control device according to claim 1,
The rust occurrence determination means has storage means for storing the pressing force and the torque, and the pressing force and torque detected this time with respect to the pressing force and torque before the previous time stored in the storage means. The vehicle braking control device according to claim 1, wherein the disc rotor is determined to have rusted when the value of is different by a predetermined value or more. The braking control device according to claim 1 or 2,
The rust occurrence determination means detects the occurrence of rust for each of the plurality of disk rotors,
The brake selection means cancels the control of braking by the friction brake in preference to the braking by the in-wheel motor when it is confirmed that no rust is generated in all the disk rotors. Braking control device. The braking control device according to any one of claims 1 to 3,
Vehicle state detection means for detecting that the vehicle is in a state where water droplets are likely to adhere to the disk rotor;
The rust occurrence determination means executes a process for determining the occurrence of rust on the disk rotor when the vehicle state detection means determines that the vehicle is in a state where water droplets are likely to adhere to the disk rotor. A vehicle braking control device.

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