JP4428239B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking control device that controls braking force applied to a vehicle wheel.

  Conventionally, when a vehicle starts, by controlling the braking force of the vehicle in relation to the driving force of the vehicle or the output torque of the power source, for example, when the vehicle starts on an uphill road, the vehicle is prevented from moving backward and smoothly. It is being started. As an example, the vehicle's stopping force (braking force or braking force) is based on the deviation between the reverse force acting on the vehicle and the driving force from the engine transmitted to the driving wheels of the vehicle when starting on an uphill road. Patent Document 1 discloses an invention relating to a device that prevents the vehicle from moving backward by acting.

  In the invention described in Patent Document 1, when the vehicle stops on an uphill road, the inclination angle of the uphill road is calculated based on the detection signal from the acceleration sensor, and the reverse force calculated according to the inclination angle is calculated. And the estimated value of the driving force transmitted from the engine to the driving wheel, that is, if the reverse force is larger than the driving force, it is determined that the vehicle moves backward without stopping on the uphill road. Thus, a braking force as a stopping force is added. For this reason, the vehicle can be stopped on an uphill road and can be prevented from moving backward when starting.

Further, in Patent Document 2, when the vehicle starts on a slope, the output torque of the engine is set based on the road gradient, and the driving torque of the vehicle in a state where the accelerator is not stepped, that is, the creep force, is determined when the vehicle stops on the slope. An invention relating to a device for preventing the vehicle from retreating when starting on a slope by controlling the vehicle to be slightly larger than the running resistance torque of the vehicle, that is, the force in the direction of retreating the vehicle is described.
JP-A-7-69102 JP-A-6-264783

  In the invention described in Patent Document 1 described above, when the vehicle stops on an uphill road, the driving force transmitted to the left and right rear wheels, which are drive wheels, is smaller than the reverse force acting on the vehicle. It is controlled so that a restraining force is added. That is, when the vehicle stops on an uphill road, the reverse force acting on the vehicle is compared with the drive force transmitted to the drive wheels, and if the drive force is smaller than the reverse force, the vehicle is retracted. Brake force is added as a stopping force to prevent. The braking force is applied to the left and right rear wheels, which are driving wheels, using a rear brake. That is, a braking force is applied to the driving wheel and held. When the vehicle starts from the stopped state, the braking force is released, that is, the holding of the braking force on the driving wheel is released when the driving force balanced with the reverse force is transmitted to the driving wheel.

  As described above, in the invention described in Patent Document 1, the stopping force for preventing the vehicle from moving backward is held as the braking force applied to the drive wheels. Therefore, when starting, the driving force transmitted to the driving wheel is increased, and when the holding of the braking force applied to the driving wheel is released when balanced with the reverse force, for example, inevitable control on the machine configuration Due to the influence of the time lag, there is a risk that a so-called brake drag may occur when the driving wheel is actuated to drive the driving wheel even when a braking force is applied to the driving wheel at the time of starting. .

  The present invention has been made paying attention to the above technical problem, and is a driving wheel to which a driving force is transmitted from a power source when controlling a braking force applied to a vehicle wheel, that is, a braking control of the vehicle. Alternatively, it is an object of the present invention to provide a control device that can prevent or reduce brake drag on main drive wheels to which mainly driving force is transmitted.

  In order to achieve the above object, a first aspect of the present invention is a vehicle braking control device that controls a braking force applied to a wheel of a vehicle having a power source, and a moving force that moves the vehicle acting on the vehicle. And a driving force calculating means for calculating a driving force transmitted from the power source to the wheels so as to move the vehicle in a direction opposite to the moving direction of the vehicle by the moving force. When the vehicle is started by the driving force, if the driving force calculated by the driving force calculating unit is smaller than the moving force calculated by the moving force calculating unit, the braking force of the wheel having a small driving force is obtained. And a braking force control means for making the braking force larger than the braking force of the wheel having the large driving force.

  According to a second aspect of the present invention, in the first aspect of the invention, the braking force control unit is configured to calculate the driving force calculated by the driving force calculation unit when the vehicle starts. The control device includes means for braking the wheel having the small driving force without braking the wheel having the large driving force when the driving force is smaller than the moving force.

  Furthermore, the invention of claim 3 is the invention of claim 1 or 2, wherein the wheel having a large driving force is a driving wheel to which the driving force is transmitted from the power source, and the wheel having a small driving force is The control device is a non-driving wheel to which the driving force is not transmitted from the power source.

  The invention according to claim 4 is the invention according to claim 1 or 2, wherein the wheel having the large driving force is a main driving wheel having a relatively large driving force transmitted from the power source, and the driving force The small control wheel is a driven wheel having a relatively small driving force transmitted from the power source.

  According to the first aspect of the present invention, when the braking force control for maintaining the stop state is executed when the vehicle is stopped, for example, when the vehicle stops on the uphill road, the vehicle is lowered by the gravity on the uphill road. A moving force that moves the vehicle acting on the vehicle, such as a force that moves in the direction, and a driving force that is transmitted from the power source to the wheels so as to move the vehicle in a direction opposite to the moving direction of the vehicle due to the moving force. Is calculated. When starting the vehicle, if the driving force is smaller than the moving force, the braking force applied to the wheel with the small driving force is made larger than the braking force applied to the wheel with the large driving force. . That is, until the driving force is increased beyond the moving force, the braking state is mainly applied to the wheels having a small driving force, so that the stopped state of the vehicle is maintained. Therefore, the movement of the vehicle due to the moving force can be prevented or suppressed, and the occurrence of so-called brake dragging on the wheel having a large driving force can be avoided or suppressed, and the wear of the brake can be reduced.

  According to the second aspect of the present invention, if the driving force is smaller than the moving force when the vehicle is started from the stop state, the wheel having a large driving force is not braked and the driving force is not braked. The smaller wheel is braked. That is, the braking force applied to the wheel having the large driving force is released, and the braking force is applied only to the wheel having the small driving force. In other words, until the driving force is increased beyond the moving force, the braking force is applied to the wheels having a small driving force, so that the stopped state of the vehicle is maintained. Therefore, the movement of the vehicle due to the moving force can be prevented or suppressed, the occurrence of so-called brake dragging on the wheel having a large driving force can be avoided, and the wear of the brake can be reduced.

  According to the third aspect of the present invention, the braking force applied to the non-driving wheels to which no driving force is transmitted is greater than the braking force applied to the driving wheels to which the driving force is transmitted from the power source. Alternatively, the non-driving wheels are braked without braking the driving wheels. That is, the braking force on the driving wheel is released and the braking force is applied only to the non-driving wheel. In other words, until the driving force is increased beyond the moving force, the braking force is applied mainly to the non-driving wheels, or the braking force to the driving wheels is released and the braking force is applied only to the non-driving wheels. As a result, the stop state of the vehicle is maintained. Therefore, the movement of the vehicle due to the moving force can be prevented or suppressed, the occurrence of so-called brake drag on the drive wheels can be avoided or suppressed, and the wear of the brake can be reduced.

  According to the fourth aspect of the present invention, the driving force transmitted from the power source is relatively smaller than the braking force applied to the main driving wheel having a relatively large driving force transmitted from the power source. The braking force applied to the drive wheels is increased. Alternatively, the main driving wheel is not braked and the follower driving wheel is braked. That is, the braking force on the main driving wheel is released and the braking force is applied only to the slave driving wheel. In other words, until the driving force is increased more than the moving force, the braking force is mainly applied to the driven wheels, or the braking force to the main driving wheels is released and the braking force is applied only to the driven wheels. By being given, the stop state of the vehicle is maintained. Therefore, the movement of the vehicle due to the moving force can be prevented or suppressed, the occurrence of so-called brake drag on the main drive wheels can be avoided or suppressed, and the wear of the brake can be reduced.

  Next, an embodiment of the present invention will be described with reference to the drawings. First, a vehicle drive system to which the present invention is applied is shown in FIG. FIG. 3 shows an example in which the vehicle Ve to which the present invention is applied is, for example, a four-wheel drive vehicle Ve. In the vehicle Ve shown in FIG. 3, a transmission 2 for shifting the rotational output of the power source 1 is disposed on the output side of the power source 1, and the transmission 2 is transmitted from the transmission 2 to the output side of the transmission 2. A transfer (sub-transmission) 5 that distributes the driving force to the front wheel side drive shaft 3 and the rear wheel side drive shaft 4 is provided.

  As the power source 1, for example, at least one of an internal combustion engine or an electric motor can be used. As the electric motor, for example, a motor generator having a power running function for converting electric energy into kinetic energy and a regenerative function for converting kinetic energy into electric energy can be used. In this embodiment, a case where an engine 1 such as a gasoline engine, a diesel engine, or a natural gas engine is used as the power source 1 will be described. Further, as the transmission 2, various transmissions such as a manual transmission, an automatic transmission, or a continuously variable transmission can be used.

  The transfer 5 is a high-speed high gear train that transmits the rotational output of the transmission 2 to the drive shafts 3 and 4 without decelerating, and the low speed that further reduces the rotational output of the transmission 2 and transmits it to the drive shafts 3 and 4. 2 gear trains, and a low gear train can be selectively switched between a high gear train and a low gear train by operating a shift lever (not shown) for the transfer 5. Has been. Further, the transfer 5 is provided with a differential (center differential) (not shown) in the inside thereof, and is configured so as to be able to absorb the rotational difference between the front wheels and the rear wheels generated when the vehicle Ve turns. Has been.

  The front wheel side drive shaft 3 is connected to the left and right front wheel drive shafts 7 and 8 via a front differential 6, and the front wheel drive shafts 7 and 8 are connected to wheels 9 and 10 serving as left and right front wheels. . Further, the rear wheel side drive shaft 4 is connected to the left and right rear wheel drive shafts 12 and 13 via the rear differential 11, and the rear wheel drive shafts 12 and 13 include wheels 14 and left and right rear wheels. 15 are connected. The output torque of the engine 1 is transmitted to the wheels 9, 10, 14, and 15 through the power transmission system formed by each mechanism.

  Here, the vehicle Ve which is the above-described four-wheel drive vehicle Ve is a four-wheel drive based on a two-wheel drive vehicle Ve ′ of an FR (front engine / rear drive) type as shown in FIG. The vehicle Ve is configured so that the output torque, that is, the driving force of the engine 1 is mainly transmitted to the left and right rear wheels 14 and 15 based on the power distribution ratio of the transfer 5. That is, the wheels with large driving force transmitted from the engine 1 are the left and right rear wheels 14 and 15, and the wheels with small driving force transmitted from the engine 1 are the left and right front wheels 9 and 10. In other words, the left and right rear wheels 14 and 15 are main drive wheels having a relatively large driving force transmitted from the engine 1, and the left and right front wheels 9 and 10 have a relative driving force transmitted from the engine 1. It can be said that this is a small driven wheel. Even when the distribution ratio of the driving force to the left and right front wheels 9 and 10 and the left and right rear wheels 14 and 15 is equal, the vehicle Ve in this embodiment is the FR type two-wheel drive vehicle Ve as described above. In the case of a four-wheel drive vehicle Ve based on ', it can be said that the left and right rear wheels 14 and 15 are main drive wheels, and the left and right front wheels 9 and 10 are slave drive wheels.

  Further, the present invention can be applied not only to the above-described four-wheel drive vehicle Ve but also to a two-wheel drive vehicle Ve ′ as shown in FIG. 4, for example. In the two-wheel drive vehicle Ve ′ shown in FIG. 4, the output torque of the engine 1 transmitted via the transmission 2 is transmitted via the rear wheel side drive shaft 4, the rear differential 11, and the left and right rear wheel drive shafts 12, 13. Thus, the driving force is transmitted to the left and right rear wheels 14 'and 15'. Therefore, the left and right rear wheels 14 'and 15' are driving wheels to which driving force is transmitted from the engine 1, and the left and right front wheels 9 'and 10' are non-driving wheels to which driving force is not transmitted. Yes.

  Thus, the two-wheel drive vehicle Ve ′ shown in FIG. 4 is different from the four-wheel drive vehicle Ve shown in FIG. 3 in that the transfer 5, the front wheel side drive shaft 3, the front differential 6, and the left and right front wheel drive shafts 7, 8 3 is substantially the same as that of the four-wheel drive vehicle Ve shown in FIG. Therefore, in the other configurations of the two-wheel drive vehicle Ve ′ shown in FIG. 4, the same parts as those shown in FIG. 3 are denoted by the same reference numerals as those shown in FIG.

  When the present invention is applied to the two-wheel drive vehicle Ve ′ as described above, the wheels having a large driving force transmitted from the engine 1, that is, the driving wheels to which the driving force is transmitted from the engine 1 are the left and right rear wheels. Wheels with small driving force transmitted from the engine 1, that is, non-driving wheels to which no driving force is transmitted from the engine 1 are the left and right front wheels 9 and 10.

  When the present invention is applied to the wheels 9, 10, 14, 15 or the two-wheel drive vehicle Ve ′ shown in FIG. 4, braking is applied to the wheels 9 ′, 10 ′, 14 ′, 15 ′. A device 16 is provided for each. Further, in the hydraulic system of the hydraulic fluid that connects the wheel cylinder 17 constituting the braking device 16 and the master cylinder 18, the hydraulic pressure in the wheel cylinder 17 is increased or decreased separately from the driver's brake operation. A brake actuator 19 is provided for controlling the braking force applied to the wheels 9, 10, 14, 15 or to the wheels 9 ', 10', 14 ', 15'. In the description of the embodiment of the present invention, “Vehicle Ve” is “Vehicle Ve ′”, “Each wheel 9, 10, 14, 15” is “Each wheel 9 ′, 10 ′, 14 ′, 15 ′”. “Main drive wheels (left and right rear wheels) 14, 15” are changed to “drive wheels (left and right rear wheels) 14 ′, 15 ′” and “sub driven wheels (left and right front wheels) 9, 10” are “non- By replacing the driving wheels (left and right front wheels) 9 ′ and 10 ′ ”with each other, the present invention can be described as applied to a two-wheel drive vehicle Ve ′ as shown in FIG. Part of the detailed description of the two-wheel drive vehicle Ve ′ will be omitted.

  FIG. 5 schematically shows the configuration of the brake actuator 19. The brake actuator 19 is configured to be able to control the hydraulic pressure independently for each braking device 16 of each wheel 9, 10, 14, 15 and FIG. A configuration of the brake actuator 19 relating to one of the wheels 9, 10, 14, and 15 is representatively shown. Accordingly, the other wheels have the same configuration.

  The hydraulic system constituting the brake actuator 19 is provided with a hydraulic pump 21 that is rotationally driven by a motor 20. The hydraulic pump 21 functions as a hydraulic pressure source when controlling the braking force, and the discharge port 21 a of the hydraulic pump 21 is connected to a pipe between the shut-off valve 23 and the holding valve 24 via a pipeline 22. It is connected to the path 25. A check valve 26 is provided on the discharge port 21 a side of the hydraulic pump 21 to block the flow of hydraulic fluid in the direction opposite to the discharge direction of the hydraulic pump 21.

  On the other hand, the suction port 21b of the hydraulic pump 27 is connected to the reservoir 28 via the conduit 27, and the flow of hydraulic fluid in the direction opposite to the suction direction of the hydraulic pump 21 is blocked in the conduit 27. Check valves 29 and 30 are provided. The pipe line 27 between the check valves 29 and 30 is connected to the reservoir tank 32 through the pipe line 31, and the hydraulic fluid in the reservoir tank 32 is supplied to the hydraulic pump 21 through the pipe line 27. It is configured to be inhaled. A suction valve 33 of a normally closed type (a type that opens when energized) is provided in the middle of the pipe 31 to open and close the pipe 31.

  The pipe 25 connecting the master cylinder 18 and the wheel cylinder 17 is provided with a normally open type (a type that closes when energized) shut-off valve 23, and hydraulic pressure control of the hydraulic fluid is executed. In this case, the valve 25 is closed to shut off the conduit 25 between the master cylinder 18 and the wheel cylinder 17. Further, a normally open type holding valve 24 is provided in the pipe line 25 closer to the wheel cylinder 17 than the shut-off valve 23. By closing the holding valve 24, the wheel cylinder 17 The hydraulic system on the side is closed, that is, the hydraulic pressure of the hydraulic system on the wheel cylinder 17 side from the holding valve 24 is maintained.

  Therefore, by controlling the holding valve 24 to the closed state, the hydraulic pressure of the hydraulic system on the wheel cylinder 17 side from the holding valve 24, that is, the brake hydraulic pressure can be held. , 14 and 15 can be held respectively.

  The conduit 25 between the holding valve 24 and the wheel cylinder 17 is connected to the reservoir 28 by a conduit 34. The pipe line 34 is provided with a normally closed type pressure reducing valve 35. The pressure reducing valve 35 is driven in a duty manner by a drive control signal in an ON / OFF binary state to change the communication state of the pipe line 34. be able to.

  Therefore, by controlling the open / close state of the pressure reducing valve 35, the communication state of the pipe line 34 can be changed, and the hydraulic pressure (brake hydraulic pressure) of the hydraulic system on the wheel cylinder 17 side from the holding valve 24 can be changed. . For example, as described above, the pressure reducing valve 35 is controlled to be opened from the state in which the brake fluid pressure is maintained, that is, the state in which the braking force applied to each of the wheels 9, 10, 14, and 15 is retained. Thus, the holding state of the braking force applied to each of the wheels 9, 10, 14, 15 can be released by bringing the pipe line 34 into a communicating state and reducing the brake fluid pressure.

  As described above, the operation of the brake actuator 19 constituted by the hydraulic pump 21 and various valve devices is controlled by the electronic control device 100. In other words, the operation of the brake actuator 19 is controlled by the electronic control device 100, and the hydraulic pressure in the wheel cylinder 17 of the braking device 16 is controlled to increase or decrease. Therefore, based on the signal output from the electronic control device 100, the braking device 16 provided in each wheel 9, 10, 14, 15 can be controlled.

  FIG. 6 schematically shows the configuration of the electronic control device 100. The electronic control device 100 detects a wheel speed sensor 101 that detects the rotational speed of each of the wheels 9, 10, 14, and 15, a shift position sensor 102 that detects the shift position of the shift lever, and a depression amount of the brake pedal 36. A brake pedal sensor 103, an accelerator pedal sensor 104 that detects the amount of depression of an accelerator pedal (not shown), a selected gear train detection sensor 105 that detects a gear train selected by a shift lever for the transfer 5, and a longitudinal direction of the vehicle Ve Various sensors such as a longitudinal acceleration sensor 106 for detecting the acceleration of the vehicle and an inclination angle sensor 107 for detecting the inclination angle of the traveling road surface are provided, and an output signal of each sensor is input to the electronic control device 100. It is configured.

  Various types of data are stored in the electronic control device 100, and the brake actuator 19 is controlled from the electronic control device 100 based on the signal input to the electronic control device 100 and the stored data. A signal is output.

  As described above, the present invention provides a driving wheel to which a driving force is transmitted from the engine 1 when the braking control of the vehicle Ve, that is, a braking force applied to each of the wheels 9, 10, 14, 15 is performed. Alternatively, the control device of the present invention is configured to execute the following control for the purpose of preventing or reducing brake dragging on the main drive wheel to which the driving force is mainly transmitted.

  FIG. 1 is a flowchart for explaining a first control example of the control, and the routine shown in this flowchart is repeatedly executed every predetermined short time. In FIG. 1, first, it is determined whether or not the vehicle Ve is in a stopped state due to depression of the brake pedal 36 by the driver's braking intention (step S1). That is, the brake pedal 36 is depressed by the driver, and at this time, for example, the braking force is applied to the wheels 9, 10, 14, 15 according to the depression force or depression amount of the brake pedal 36 detected by the brake pedal sensor 103, for example. It is determined whether or not the vehicle Ve is stopped by the braking force. In this case, the determination of the stop state of the vehicle Ve can be made, for example, when the detection results of the wheel speed sensors 101 that detect the rotational speeds of the wheels 9, 10, 14, and 15 are all zero.

  If the vehicle Ve is not in a stopped state, for example, if at least one of the detection results of the wheel speed sensors 101 is not zero, and the determination is negative in this step S1, the subsequent control is not executed. This routine is once terminated.

  On the other hand, if the vehicle Ve is in a stopped state and the determination is affirmative in step S1, the process proceeds to step S2, the road surface gradient is calculated, and the data is stored. This road surface gradient calculation process can be obtained, for example, from the detection result of the inclination angle sensor 107 mounted on the vehicle Ve. Or it can also estimate based on the detection result of the acceleration in the front-back direction of the vehicle Ve according to the road surface gradient obtained by the front-back acceleration sensor 106. It is also possible to estimate from the change state of the rotational speed of each wheel 9, 10, 14, 15 obtained by the wheel speed sensor 101. Alternatively, it can be estimated based on geographic information obtained from a navigation system (not shown).

  Subsequently, the moving force for moving the vehicle Ve acting on the vehicle Ve is calculated, and the data is stored (step S3). The moving force that moves the vehicle Ve is, for example, a force that lowers the vehicle Ve in the downhill direction of the slope due to the action of gravity when the vehicle Ve stops in the middle of the slope, and is calculated in step S2 above. It can be calculated from the road surface gradient and the vehicle weight of the vehicle Ve. Further, even when the road surface gradient is zero, for example, when the force to move the vehicle Ve acts on the vehicle Ve due to the influence of strong winds, for example, the acceleration sensor 106 described above can be used. From the detection result of the longitudinal acceleration of the vehicle Ve to be obtained or the change in the rotational speed of each wheel 9, 10, 14, 15 obtained by the wheel speed sensor 101, the moving force acting on the vehicle Ve in that case is estimated. Can be calculated.

  Based on the moving force acting on the vehicle Ve calculated in step S3, the braking force acting on the vehicle Ve is obtained, and the braking force is held (step S4). Specifically, a braking force necessary to maintain the vehicle Ve in a stopped state against the moving force acting on the vehicle Ve is obtained, and the braking force is applied to each of the wheels 9, 10, 14, and 15. It is held in the state. That is, as described above, the brake fluid pressure is held by controlling the holding valve 24 of the brake actuator 19 to be closed, and the braking force applied to each of the wheels 9, 10, 14, and 15 is controlled. Are held respectively.

  When the braking force of the vehicle Ve, that is, the braking force applied to each of the wheels 9, 10, 14, 15 is maintained, it is determined whether or not the brake pedal 36 that has been depressed by the driver is released (step S5). ). In this case, the determination of the released state of the brake pedal 36 can be made, for example, based on a detection result such as a depression force or a depression amount of the brake pedal 36 detected by the brake pedal sensor 103.

  If a negative determination is made in step S5 because the brake pedal 36 has not been released, it is determined that the driver is not yet ready to start, the process returns to step S3, and the subsequent control is repeatedly executed. Is done.

  On the other hand, if the determination in step S5 is affirmative due to the release of the brake pedal 36, the process proceeds to step S6, where the shift position position or gear position of the transmission 2 selected by operating the shift lever or the like is determined. Then, it is determined whether or not it is a shift position position or a gear position for starting.

  For example, when the transmission 2 mounted on the vehicle Ve is an automatic transmission, the shift position position or gear position for starting is the shift position position of the transmission 2 selected by operating a shift lever or the like. , D (drive) range or R (reverse) range, particularly when the transmission is a stepped automatic transmission, in addition to these D range and R range, The 1st speed range or the 2nd (2nd speed) range can also be used as the shift position for starting. For example, when the transmission 2 mounted on the vehicle Ve is a manual transmission, a depression of a clutch pedal (not shown) of a predetermined amount or more is detected by, for example, a clutch pedal sensor (not shown), A state where the gear position of the transmission 2 selected by operating the shift lever or the like is shifted to a gear position such as a low gear or a reverse gear can be set as a gear position for starting.

  The shift position position or gear position of the transmission 2 is not a shift position position or gear position for starting, that is, for example, when the transmission 2 is an automatic transmission, the shift position position is N (neutral) Range or P (parking) range, etc., or when the transmission 2 is a manual transmission, the gear position is in a neutral state or the clutch pedal is depressed more than a predetermined amount. Thus, if a negative determination is made in this step S6, it is determined that the driver is not yet ready to start, the process returns to step S3, and the subsequent control is repeatedly executed.

  On the other hand, if the shift position position or gear position of the transmission 2 is a shift position position or gear position for starting, and if a positive determination is made in step S6, the process proceeds to step S7, for example, an accelerator pedal. It is determined whether or not the driver is willing to start by stepping on (not shown). In this case, the determination of the presence or absence of the driver's intention to start can be determined that the driver has the intention to start when, for example, the amount of depression of the accelerator pedal detected by the accelerator pedal sensor 104 is a predetermined amount or more. In addition to the depression amount of the accelerator pedal, the presence or absence of the driver's intention to start is determined based on the operation amount in a predetermined device that increases or decreases the throttle opening of the engine 1 according to the operation amount, for example, the operation amount of the accelerator lever. Judgment can be made.

  If a negative determination is made in this step S7 because the driver does not intend to start, that is, for example, the depression of an accelerator pedal of a predetermined amount or more is not detected, the process returns to step S3, and the subsequent control Is repeatedly executed.

  On the other hand, for example, when it is determined that the driver is willing to start by detecting depression of an accelerator pedal of a predetermined amount or more, and when the determination is affirmative in step S7, the process proceeds to step S8, where each wheel 9, Of the braking force applied to and retained on 10, 14, and 15, the retained state of the braking force applied to the main drive wheels, that is, the left and right rear wheels 14 and 15, is released. Specifically, as described above, the pressure reducing valve 35 in the brake actuator 19 is controlled to be in an open state, the conduit 34 is brought into a communication state, and the brake fluid pressure is reduced, whereby the main drive wheels, i. The holding state of the braking force applied to the rear wheels 14 and 15 is released. In other words, the magnitude of the braking force applied to the main drive wheels, that is, the left and right rear wheels 14 and 15 is reduced to zero. When the present invention is applied to the two-wheel drive vehicle Ve ', the holding state of the braking force applied to the drive wheels, that is, the left and right rear wheels 14' and 15 'is released. In other words, the magnitude of the braking force applied to the drive wheels, that is, the left and right rear wheels 14 ', 15' is reduced to zero.

  At this time, among the braking forces applied and held to the wheels 9, 10, 14, and 15, the holding state of the braking force applied to the driven wheels, that is, the left and right front wheels 9 and 10, is maintained as it is. The stop state of the vehicle Ve is maintained. That is, when the vehicle Ve starts due to the driver's intention to start, wheels having a large driving force transmitted from the engine 1, in other words, main driving wheels having a relatively large driving force transmitted from the engine 1, that is, left and right rear wheels. 14 and 15 are not applied with a braking force, and are wheels having a small driving force transmitted from the engine 1, in other words, driven wheels having a relatively small driving force transmitted from the engine 1, that is, left and right front wheels 9. , 10 is applied with a braking force, the vehicle Ve is maintained in a stopped state. In addition, when the present invention is applied to the two-wheel drive vehicle Ve ′, the non-drive wheels, that is, the left and right wheels among the braking forces applied to and held by the wheels 9 ′, 10 ′, 14 ′, and 15 ′. The holding state of the braking force applied to the front wheels 9 ′ and 10 ′ is maintained as it is, and the stopped state of the vehicle Ve ′ is maintained. That is, when the vehicle Ve ′ starts due to the driver's intention to start, wheels having a large driving force transmitted from the engine 1, in other words, driving wheels to which the driving force is transmitted from the engine 1, that is, left and right rear wheels 14 ′, 15. The braking force is not applied to the wheel with a small driving force transmitted from the engine 1, in other words, the braking force is applied to the non-driving wheels to which the driving force is not transmitted from the engine 1, that is, the left and right front wheels 9 ', 10'. Is given, the stop state of the vehicle Ve ′ is maintained.

  Subsequently, it is determined whether or not the driving force transmitted from the engine 1 to the main driving wheels, that is, the left and right rear wheels 14 and 15 is larger than the moving force that moves the vehicle Ve acting on the vehicle Ve (step S9). ). When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve ′ in which the driving force transmitted from the engine 1 to the drive wheels, that is, the left and right rear wheels 14 ′ and 15 ′, acts on the vehicle Ve ′. It is determined whether or not it is greater than the moving force for moving the.

  A negative determination was made in this step S9 because the driving force transmitted from the engine 1 to the main driving wheels, that is, the left and right rear wheels 14, 15 is less than the moving force that moves the vehicle Ve acting on the vehicle Ve. In this case, the process returns to step S3, and the subsequent control is repeatedly executed. When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve ′ in which the driving force transmitted from the engine 1 to the drive wheels, that is, the left and right rear wheels 14 ′ and 15 ′, acts on the vehicle Ve ′. If the determination is negative in step S9 due to the moving force being less than or equal to the moving force, the process returns to step S3 and the subsequent control is repeatedly executed.

  On the other hand, since the driving force transmitted from the engine 1 to the main driving wheels, that is, the left and right rear wheels 14 and 15 is larger than the moving force that moves the vehicle Ve acting on the vehicle Ve, the determination in step S9 is affirmative. If this is the case, the process proceeds to step S10, the holding state of the braking force applied to the driven wheels, that is, the left and right front wheels 9, 10, is released, and the vehicle Ve starts to be started by the driving force transmitted from the engine 1. The Thereafter, this routine is once terminated. When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve ′ in which the driving force transmitted from the engine 1 to the drive wheels, that is, the left and right rear wheels 14 ′ and 15 ′, acts on the vehicle Ve ′. If the determination result is affirmative in step S9, the process proceeds to step S10, and the braking force applied to the non-driven wheels, that is, the left and right front wheels 9 'and 10' is maintained. The state is released, and the vehicle Ve ′ starts to be started by the driving force transmitted from the engine 1. Thereafter, this routine is once terminated.

  That is, the magnitude of the driving force transmitted from the engine 1 to the main driving wheels, that is, the left and right rear wheels 14 and 15, which is increased when the vehicle Ve starts, and the magnitude of the moving force that moves the vehicle Ve acting on the vehicle Ve. To be compared. When the magnitude of the driving force becomes larger than the magnitude of the moving force, the vehicle Ve moves even if the holding state of the braking force applied to the slave driving wheels, that is, the left and right front wheels 9 and 10 is released. It can be determined that the vehicle Ve is not lowered in the downhill direction due to the action of gravity when the vehicle Ve is stopped in the middle of the slope, for example, when it is moved by force. The holding state of the braking force applied to the driven wheels, that is, the left and right front wheels 9, 10 is released, and the vehicle Ve starts to start. When the present invention is applied to the two-wheel drive vehicle Ve ′, the driving force transmitted from the engine 1 to the drive wheels, that is, the left and right rear wheels 14 ′ and 15 ′, which is increased when the vehicle Ve ′ starts, is large. And the magnitude of the moving force that moves the vehicle Ve ′ acting on the vehicle Ve ′. When the magnitude of the driving force becomes larger than the magnitude of the moving force, the holding state of the braking force applied to the non-driving wheels, that is, the left and right front wheels 9 ′, 10 ′ is released, and the vehicle Ve ′ Start is started.

  By executing the control as described above, when trying to start the vehicles Ve and Ve ′, each wheel 9, 10, 14, 15 or each wheel 9 ′, 10 ′, 14 ′ from the engine 1 is started. , 15 ′ is smaller than the moving force for moving the vehicles Ve, Ve ′ acting on the vehicles Ve, Ve ′, the left and right wheels that are the main driving wheels, that is, the main driving wheels. The rear wheels 14 and 15 or the left and right rear wheels 14 'and 15', which are driving wheels, are not braked and are wheels with a small driving force, that is, left and right front wheels 9 and 10 which are driven wheels, or non-driving wheels. Certain left and right front wheels 9 ', 10' are braked. That is, the braking force applied to the left and right rear wheels 14 and 15 that are the main driving wheels or the left and right rear wheels 14 'and 15' that are the driving wheels is released, and the left and right front wheels 9 and 10 that are the driven wheels, or A braking force is applied only to the left and right front wheels 9 'and 10' which are non-drive wheels. In other words, the braking force is applied to the left and right front wheels 9 and 10 that are the driven wheels or the left and right front wheels 9 'and 10' that are the non-driven wheels until the driving force is increased beyond the moving force. Thus, the stopped state of the vehicles Ve and Ve ′ is maintained.

  Therefore, the movement of the vehicles Ve and Ve ′ due to the moving force can be prevented or suppressed, and the wheels having a large driving force, that is, the left and right rear wheels 14 and 15 which are main driving wheels, or the left and right rear wheels which are driving wheels. Occurrence of so-called brake dragging on the wheels 14 ′ and 15 ′ can be avoided, and wear of the brake can be reduced.

  FIG. 2 is a flowchart for explaining a second control example by the braking control apparatus according to the present invention. Like the routine shown in the flowchart of FIG. 1, the routine shown in the flowchart of FIG. Repeated every hour. In addition, the second control example shown in the flowchart of FIG. 2 is obtained by changing the control contents of steps S8 and S10 in the first control example shown in the flowchart of FIG. For this reason, steps having the same control content are denoted by the same step numbers as the step numbers given in the flowchart of FIG.

  That is, in FIG. 2, as in the case of the first control example shown in the flowchart of FIG. 1, the control in steps S1 to S7 is executed. In step S7, it is determined that the driver has a willingness to start. If the determination in step S7 is affirmative, the process proceeds to step S21 where the braking force applied to each wheel 9, 10, 14, 15 is applied and held in a state of being distributed at a predetermined rate. The That is, from the state in which a substantially equal braking force is applied to and maintained on each of the wheels 9, 10, 14, and 15, the wheels having a small driving force to be transmitted, that is, the left and right front wheels 9 and 10 that are driven wheels are transmitted. The applied braking force is distributed so as to be larger than the braking force applied to the wheels having a large transmitted driving force, that is, the left and right rear wheels 14 and 15, which are the main driving wheels, and the state is maintained. .

  Specifically, for example, the opening / closing state of the pressure reducing valve 35 in the brake actuator 19 is controlled, so that the brake fluid pressure of the driven wheels, that is, the left and right front wheels 9, 10 is changed to the main driving wheels, that is, the left and right rear wheels 14, 15. By reducing the brake fluid pressure of the main drive wheels, that is, the left and right rear wheels 14, 15 so as to be higher than the brake fluid pressure, the braking force applied to the slave drive wheels, that is, the left and right front wheels 9, 10 is The distribution is made so as to be larger than the braking force applied to the main drive wheels, that is, the left and right rear wheels 14, 15, and the state is maintained. When the present invention is applied to the two-wheel drive vehicle Ve ′, the braking force applied to the non-drive wheels, that is, the left and right front wheels 9 ′, 10 ′ is the drive wheels, that is, the left and right rear wheels 14 ′, 15 ′. Is distributed so as to be larger than the braking force applied to the motor, and the state is maintained.

  Subsequently, it is determined whether or not the driving force transmitted from the engine 1 to each of the wheels 9, 10, 14, and 15 is greater than the moving force that moves the vehicle Ve acting on the vehicle Ve (step S9). When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve in which the driving force transmitted from the engine 1 to the wheels 9 ′, 10 ′, 14 ′, 15 ′ acts on the vehicle Ve ′. It is determined whether or not it is larger than the moving force for moving '.

  If the driving force transmitted from the engine 1 to each of the wheels 9, 10, 14, and 15 is less than or equal to the moving force that moves the vehicle Ve acting on the vehicle Ve, a negative determination is made in this step S9. Returning to step S3, the subsequent control is repeatedly executed. When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve in which the driving force transmitted from the engine 1 to the wheels 9 ′, 10 ′, 14 ′, 15 ′ acts on the vehicle Ve ′. If it is determined in step S9 to be negative because it is equal to or less than the moving force for moving ', the process returns to step S3, and the subsequent control is repeatedly executed.

  On the other hand, when the driving force transmitted from the engine 1 to each of the wheels 9, 10, 14, and 15 is larger than the moving force that moves the vehicle Ve acting on the vehicle Ve, a positive determination is made in step S9. In step S22, the holding state of the braking force distributed and applied to each of the wheels 9, 10, 14, and 15 is released, and the vehicle Ve starts to be started by the driving force transmitted from the engine 1. Is done. Thereafter, this routine is once terminated. When the present invention is applied to the two-wheel drive vehicle Ve ′, the vehicle Ve in which the driving force transmitted from the engine 1 to the wheels 9 ′, 10 ′, 14 ′, 15 ′ acts on the vehicle Ve ′. If it is determined affirmative in step S9 by being larger than the moving force for moving ', the process proceeds to step S22 and is distributed and given to each wheel 9', 10 ', 14', 15 '. The held state of the braking force is released, and the vehicle Ve ′ starts to be started by the driving force transmitted from the engine 1. Thereafter, this routine is once terminated.

  That is, the magnitude of the driving force transmitted from the engine 1 to the wheels 9, 10, 14, and 15 that is increased when the vehicle Ve starts is compared with the magnitude of the moving force that moves the vehicle Ve acting on the vehicle Ve. The Even when the holding state of the braking force distributed and applied to each of the wheels 9, 10, 14, and 15 is canceled when the magnitude of the driving force becomes larger than the magnitude of the moving force, the vehicle Since it can be determined that Ve is not moved by the moving force, in that case, the holding state of the braking force distributed and applied to each of the wheels 9, 10, 14, and 15 is released, The start of the vehicle Ve is started. When the present invention is applied to the two-wheel drive vehicle Ve ′, the driving force transmitted from the engine 1 to the wheels 9 ′, 10 ′, 14 ′, 15 ′, which is increased when the vehicle Ve ′ starts, The magnitude and the magnitude of the moving force that moves the vehicle Ve ′ acting on the vehicle Ve ′ are compared. And when the magnitude of the driving force becomes larger than the magnitude of the moving force, the holding state of the braking force distributed and applied to each of the wheels 9 ′, 10 ′, 14 ′, 15 ′ is released. Then, the start of the vehicle Ve ′ is started.

  By executing the control as described above, when trying to start the vehicles Ve and Ve ′, each wheel 9, 10, 14, 15 or each wheel 9 ′, 10 ′, 14 ′ from the engine 1 is started. , 15 ′ is smaller than the moving force for moving the vehicles Ve, Ve ′ acting on the vehicles Ve, Ve ′, the left and right wheels which are the small driving forces, that is, the driven wheels. The braking force applied to the front wheels 9, 10 or the left and right front wheels 9 ′, 10 ′, which are non-driving wheels, has a large driving force, that is, the left and right rear wheels 14, 15 which are main driving wheels, or the driving wheels. The left and right rear wheels 14 ′ and 15 ′ are distributed and held so as to be larger than the braking force applied to the left and right rear wheels 14 ′ and 15 ′. In other words, until the driving force is increased beyond the moving force, the braking force is mainly applied to the left and right front wheels 9 and 10 that are the driven wheels or the left and right front wheels 9 'and 10' that are the non-driving wheels. Thus, the stopped state of the vehicles Ve and Ve ′ is maintained.

  Therefore, the vehicle Ve, which is driven by a moving force, is mainly applied by the braking force applied to the wheels having a small driving force, that is, the left and right front wheels 9 and 10 which are driven wheels or the left and right front wheels 9 'and 10' which are non-driving wheels. Until the driving force is increased beyond the moving force while preventing or suppressing the movement of Ve ′, the wheels have a large driving force, that is, the left and right rear wheels 14 and 15 that are main driving wheels, or the driving wheels. The braking force applied to the left and right rear wheels 14 ′ and 15 ′ can also prevent or suppress the movement of the vehicles Ve and Ve ′ due to the moving force, and can more reliably prevent the movement of the vehicles Ve and Ve ′. Can be suppressed. At the same time, a so-called brake is applied to the wheels having relatively large driving force that the brake is likely to wear, that is, the left and right rear wheels 14 and 15 as the main driving wheels or the left and right rear wheels 14 'and 15' as the driving wheels. The occurrence of dragging can be avoided or suppressed, and the wear of the brake can be reduced.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means in steps S2 and S3 described above correspond to the moving force calculation means in the present invention, and the functions in steps S9 and S21. The target means corresponds to the driving force calculation means of the present invention. The functional means of steps S7 to S9 and steps S7, S21, S9 correspond to the braking force control means of the present invention. Among them, the functional means of steps S7 to S9 correspond to means for braking a wheel with a small driving force without braking a wheel with a large driving force in claim 2 of the present invention.

  The present invention is not limited to the above specific example, and the brake actuator for controlling the braking force applied to the wheels operates the hole cylinder by the hydraulic pressure of the hydraulic fluid as shown in FIG. Although an actuator is illustrated as an example, an actuator that operates to apply a braking force to a wheel by an electric servo motor, for example, may be used. Any mechanism that controls power may be used.

  In addition, as shown in FIG. 6, an example in which an inclination angle sensor is provided as a sensor for detecting a road surface gradient is shown, but without providing an inclination angle sensor, a longitudinal acceleration sensor, a wheel speed sensor, etc. It is also possible to estimate the road gradient based on the detected value.

It is a flowchart for demonstrating the 1st control example by the control apparatus of this invention. It is a flowchart for demonstrating the 2nd control example by the control apparatus of this invention. It is a conceptual diagram which shows typically the power train and control system of a four-wheel drive vehicle which can apply the control apparatus of this invention. It is a conceptual diagram which shows typically the power train and control system of the two-wheel drive vehicle which can apply the control apparatus of this invention. It is a conceptual diagram which shows typically the hydraulic system regarding the braking force control of one wheel among the structures of the brake actuator used for the control apparatus of this invention. It is a block diagram which shows roughly the control system used for the control apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power source (engine), 2 ... Transmission, 9, 10, 14, 15 (9 ', 10', 14 ', 15') ... Wheel, 16 ... Braking device, 17 ... Wheel cylinder, 19 ... Brake actuator 36 ... Brake pedal, 100 ... Electronic control unit, Ve (Ve ') ... Vehicle.

Claims (4)

In a vehicle braking control apparatus for controlling a braking force applied to a wheel of a vehicle having a power source,
A moving force calculating means for calculating a moving force for moving the vehicle acting on the vehicle;
Driving force calculating means for calculating a driving force transmitted from the power source to the wheels so as to move the vehicle in a direction opposite to the moving direction of the vehicle by the moving force;
When the vehicle is started by the driving force, when the driving force calculated by the driving force calculating unit is smaller than the moving force calculated by the moving force calculating unit, the braking force of the wheel having the small driving force is set. A braking control device for a vehicle, comprising braking force control means for making the braking force of a wheel having a large driving force larger than the braking force.   The braking force control unit brakes a wheel having a large driving force when the vehicle starts moving when the driving force calculated by the driving force calculating unit is smaller than the moving force calculated by the moving force calculating unit. The vehicle braking control device according to claim 1, further comprising a unit that brakes the wheel having a small driving force.   The wheel having the large driving force is a driving wheel to which the driving force is transmitted from the power source, and the wheel having the small driving force is a non-driving wheel to which the driving force is not transmitted from the power source. The braking control device for a vehicle according to claim 1 or 2.   The wheel having a large driving force is a main driving wheel having a relatively large driving force transmitted from the power source, and the wheel having a small driving force is a relative driving force transmitted from the power source. The vehicle braking control device according to claim 1, wherein the vehicle is a small driven wheel.

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