JP4462046B2 - 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. 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 control of the restraining force for preventing the vehicle from moving backward is performed by controlling the braking force on the drive wheels. Accordingly, when the vehicle stops on an uphill road and when the vehicle starts from the stopped state, the driving force applied to the driving wheel and the braking force applied to the driving wheel are applied to the driving wheel. It will be. Therefore, the control of the driving force and the braking force is performed together, and the contents of the braking control of the vehicle and the configuration for executing the braking control may be complicated.

  The present invention has been made paying attention to the above technical problem, and when executing control of the braking force applied to the wheels of the vehicle, that is, braking control of the vehicle, the contents of the braking control and the control are executed. It is an object of the present invention to provide a control device that simplifies the configuration for achieving this and can easily execute the braking control.

To achieve the above object movement, a first aspect of the invention, the brake control apparatus for a vehicle which controls a braking force applied to a wheel of a vehicle having a power source, for moving the vehicle to act before Symbol vehicle a moving force calculating means for calculating the force, if the moving force calculated is smaller than a predetermined reference value by the moving force calculating means, wherein by the driving force transmitted to the wheels from the kinetic power source Braking force control means for controlling the braking force for maintaining the stop state of the vehicle prior to starting of the vehicle by braking the wheel having the small driving force without braking the wheel having the large driving force; It is the control apparatus characterized by having.

Further, the invention according to claim 2 provides the drive according to the invention according to claim 1 , wherein the braking force control means performs the driving when the movement force calculated by the movement force calculation means is equal to or greater than a predetermined reference value. The control device includes means for braking the wheel having the large driving force in addition to the wheel having the small force.

Furthermore, the invention of claim 3 further comprises driving force calculating means for calculating the driving force according to the invention of claim 1 , wherein the braking force control means is configured to drive the vehicle when the vehicle is started by the driving force. Means for braking a wheel having a small driving force without braking a wheel having a large driving force when the driving force calculated by a force calculating means is smaller than the moving force calculated by the moving force calculating means; It is a control device characterized by including.

Furthermore, the invention of claim 4 is the invention according to any one of claims 1 to 3 , 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 driving force The small control wheel is a non-driving wheel to which the driving force is not transmitted from the power source.

The invention according to claim 5 is the invention according to any one of claims 1 to 3 , wherein the wheel having a large driving force is a main driving wheel having a relatively large driving force transmitted from the power source. The control device is characterized in that the wheel having a small driving force is a driven wheel having a relatively small driving force transmitted from the power source.

  According to the first aspect of the present invention, in order to maintain the stop state when the vehicle is stopped, the wheel having the large driving force transmitted from the power source to the wheel is not braked, and the wheel having the small driving force is braked. That is, the braking force is applied only to the wheel having a small driving force. In other words, the stopping state of the vehicle is maintained by applying the braking force only to the wheels having a small driving force. Therefore, compared to, for example, a case where control is performed so that braking force is applied to all wheels, the content of the braking control and the configuration for executing the control can be simplified, and the braking control can be executed easily. In addition, when starting the vehicle, it is possible to avoid the occurrence of so-called brake dragging on a wheel having a large driving force, and to reduce brake wear.

Further, when the control of the braking force to maintain its stopped state at the time of stopping vehicles is performed, for example, to move the vehicle by gravity when the vehicle was stopped in uphill the drop direction uphill A moving force for moving the vehicle acting on the vehicle, such as a force, is calculated. When the moving force is smaller than a predetermined reference value, that is, when the moving force acting on the vehicle is small and a relatively large braking force is not required to counter the moving force, the power source A wheel with a large driving force transmitted from the wheel to a wheel is not braked, and a wheel with a small driving force is braked. That is, the braking force is applied only to the wheel having a small driving force. In other words, the stopping state of the vehicle is maintained by applying the braking force only to the wheels having a small driving force. Therefore, compared to, for example, a case where control is performed so that braking force is applied to all wheels, the content of the braking control and the configuration for executing the control can be simplified, and the braking control can be executed easily. In addition, when starting the vehicle, it is possible to avoid the occurrence of so-called brake dragging on a wheel having a large driving force, and to reduce brake wear.

Furthermore, according to the invention of claim 2 , when the moving force is equal to or greater than a predetermined reference value, that is, the moving force acting on the vehicle is large, and a relatively large braking force is applied to counter the moving force. When necessary, wheels with high driving force are braked in addition to wheels with low driving force. That is, braking force is applied to all wheels. Therefore, even when there is a possibility that the moving force is large and the vehicle can be moved by the moving force, the braking force is applied to all the wheels, thereby increasing the contact area with respect to the road surface of the braked wheels, The braking force of the vehicle can be increased, and as a result, the stopped state of the vehicle can be more reliably maintained.

Further, according to the invention of claim 3 , when the vehicle is started, if the driving force is smaller than the moving force, the wheel having the small driving force is braked without braking the wheel having the large driving force. That is, the braking force is applied only to the wheel having a small driving force. In other words, until the driving force is increased beyond the moving force, the braking state is applied to the wheels having a small driving force, so that the vehicle is stopped. Therefore, compared to, for example, a case where control is performed so that braking force is applied to all wheels, the content of the braking control and the configuration for executing the control can be simplified, and the braking control can be executed easily. In addition, when starting the vehicle, it is possible to avoid the occurrence of so-called brake dragging on a wheel having a large driving force, and to reduce brake wear.

Furthermore, according to the invention of claim 4, the driving wheels to which the driving force is transmitted from the power source are not braked, and the non-driving wheels to which the driving force is not transmitted are braked. That is, the braking force is applied only to the non-driving wheels. In other words, the stopping state of the vehicle is maintained by applying the braking force only to the non-driving wheels. Therefore, for example, when starting the vehicle, it is possible to avoid so-called brake dragging on the drive wheels, and to reduce wear of brakes that brake the drive wheels.

According to the fifth aspect of the present invention, the main driving wheel having a relatively large driving force transmitted from the power source is not braked, and the slave driving wheel having a relatively small driving force transmitted from the power source is braked. Is done. That is, the braking force is applied only to the driven wheels. In other words, the stopping state of the vehicle is maintained by applying the braking force only to the driven wheels. Therefore, for example, when the vehicle is started, it is possible to avoid so-called brake dragging on the main drive wheels, and to reduce wear of brakes that brake the main drive wheels.

  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 driving force transmitted from the transmission 2 passes through the rear wheel side drive shaft 4, the rear differential 11, and the left and right rear wheel drive shafts 12 and 13, and the left and right rear wheels 14 '. It is configured so that it is transmitted to ', 15' and not transmitted to the left and right front wheels 9 ', 10'. In the two-wheel drive vehicle Ve ′ shown in FIG. 4, the output torque of the engine 1 transmitted via the transmission 2 is applied to the drive shaft 4 on the rear wheel side, the rear differential 11, and the left and right rear wheel drive shafts 12 and 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 21 is connected to the reservoir 28 via a 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 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.

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

  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 switch 105 that detects a gear train selected by a shift lever for the transfer 5, and each wheel 9, 10 , 14, 15, a driving torque sensor 106 for detecting the driving torque of the vehicle Ve, a longitudinal acceleration sensor 107 for detecting the longitudinal acceleration of the vehicle Ve, and an inclination angle sensor 108 for detecting the inclination angle of the traveling road surface. The output signals of these sensors enter the electronic control device 100. It is configured to be.

  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, in the present invention, when the braking control of the vehicle Ve, that is, the control of the braking force applied to each of the wheels 9, 10, 14, 15 is executed, the contents of the braking control and the control are executed. For this purpose, the control device of the present invention is configured to execute the following control. The control device of the present invention is configured to execute the braking control easily.

  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 in step S1 is affirmative, the process proceeds to step S2, the road surface inclination angle is calculated, and the data is stored. This road surface inclination angle calculation process can be obtained from the detection result of the inclination angle sensor 108 mounted on the vehicle Ve, for example. 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 inclination angle obtained by the front-rear acceleration sensor 107. 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, it is determined whether or not the road surface inclination angle obtained in step S2 is smaller than the reference value α (step S3). Here, the reference value α is a state in which the braking force is applied to each of the wheels 9, 10, 14, and 15, specifically, the left and right rear wheels 14 and 15 that are all wheels, that is, the main driving wheels, and the left and right driving wheels. A state in which a braking force is applied to the front wheels 9 and 10, and a state in which a braking force is applied to the left and right front wheels 9 and 10 that are driven wheels without applying a braking force to the left and right rear wheels 14 and 15 that are main driving wheels. Is a predetermined threshold value for selectively setting appropriately according to the magnitude of the road surface inclination angle.

  That is, when the road surface inclination angle is smaller than the reference value α, the force acting on the stopped vehicle Ve to lower the vehicle Ve due to gravity in the downhill direction of the inclined surface is small, and the relative force is used to counter the force. Therefore, it can be determined that a large braking force is not necessary, and the state in which the braking force is not applied to the main driving wheels 14 and 15 but the braking force is applied to the driven wheels 9 and 10 is selected and set. On the other hand, when the road surface inclination angle is equal to or greater than the reference value α, the force acting on the stopped vehicle Ve to lower the vehicle Ve due to gravity in the downhill direction of the inclined surface is large, and this force is countered. Therefore, since it can be determined that a relatively large braking force is required, a state in which the braking force is applied to all the wheels 9, 10, 14, and 15 is selected and set.

  Therefore, if the road surface inclination angle is smaller than the reference value α and the determination in step S3 is affirmative, the process proceeds to step S4, where braking force is applied to the main driving wheels 14 and 15 having large driving force. Instead, the braking force is applied to the driven wheels 9 and 10 having a small driving force, and the braking force is maintained. On the other hand, when the road surface inclination angle is greater than or equal to the reference value α, if a negative determination is made in step S3, the process proceeds to step S5 and braking force is applied to all the wheels 9, 10, 14, and 15. Thus, the braking force is maintained. Specifically, as described above, the brake fluid pressure is maintained by controlling the holding valve 24 of the brake actuator 19 to be in the closed state, and the braking force applied to the driven wheels 9 and 10. Alternatively, the braking force applied to all the wheels 9, 10, 14, 15 is maintained.

  As described above, the road surface inclination angle obtained in step S2 described above is moved according to the magnitude of the angle, for example, when the vehicle Ve stops in the middle of a slope, and the vehicle Ve is moved in the downhill direction by the action of gravity. It is a parameter that can estimate the magnitude of the force to be applied. Further, the force for moving the vehicle Ve in the downhill direction of the slope due to the action of gravity or the force for moving the vehicle Ve acting on the vehicle Ve due to the influence of an external force such as a strong wind is used in the present invention. This corresponds to a so-called movement force. Therefore, it can be said that the road surface inclination angle also corresponds to the so-called movement force in the present invention. The force to move the vehicle Ve acting on the vehicle Ve due to the influence of the strong wind as described above is, for example, the detection result of the longitudinal acceleration of the vehicle Ve obtained by the longitudinal acceleration sensor 107 described above, or the wheel speed. From the change state of the rotational speed of each wheel 9, 10, 14, 15 obtained by the sensor 101, the moving force acting on the vehicle Ve in that case can be estimated and calculated.

  When the braking force is not applied to the main driving wheels 14 and 15 and the braking force is applied to the driven wheels 9 and 10 in step S4, or all the wheels 9 and 10 are retained in step S5. , 14 and 15 are applied with a braking force and held, for example, the shift position or gear position of the transmission 2 selected by operating a shift lever or the like becomes the shift position or gear position for starting. It is determined whether or not the driver is willing to start due to the shift (step S6).

  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 the 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 due to depression of (not shown). In this case, whether or not the driver is willing to start is determined, for example, when the amount of depression of the accelerator pedal detected by the accelerator pedal sensor 104 is a predetermined amount or more and the depression is continued. It can be determined that there is a will. 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. It can also be judged.

  In step S7, the driver is not willing to start, that is, for example, that the accelerator pedal depression of a predetermined amount or more is not detected, or that the accelerator pedal depression is interrupted without being continued. If it is determined, the process returns to step S3, and the subsequent control is repeatedly executed.

  On the other hand, for example, when the accelerator pedal depression of a predetermined amount or more is detected and the depression is continued, it is determined that the driver is willing to start, that is, if the determination in step S7 is affirmative, step S8 is performed. Then, for example, it is determined whether or not the drive torque detected by the drive torque sensor 106 is equal to or greater than the reference value β.

  Here, the reference value β indicates that the output torque of the engine 1 increases as the accelerator pedal is depressed by the driver's intention to start, and the depression continues, and accordingly, the drive torque increases the smooth start of the vehicle Ve. Therefore, it is a threshold value for detecting that it has been increased to a necessary size, and is a predetermined value set according to the detection result of the road surface inclination angle. Therefore, it can be said that this reference value β also corresponds to the so-called movement force in the present invention as described above.

  If the drive torque is smaller than the reference value β and a negative determination is made in step S8, the process returns to step S7 to wait for the drive torque to increase, and the subsequent control is repeatedly executed. . In other words, when the driving torque, that is, the driving force transmitted from the engine 1 to the driven wheels 9, 10, or all the wheels 9, 10, 14, 15 is smaller than the moving force, the main driving wheels 14, A braking force is applied to the driven wheels 9 and 10 having a small driving force without applying a braking force to 15.

  On the other hand, if the drive torque is equal to or greater than the reference value β and the determination is affirmative in step S8, the process proceeds to step S9 and the driven wheels 9, 10, or all the wheels 9, 10, 14, 15 are moved. The holding state of the applied braking force 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 hydraulic pressure is reduced, whereby the driven wheels 9 and 10 are driven. Alternatively, the holding state of the braking force applied to all the wheels 9, 10, 14, 15 is released. Then, when the braking force of the vehicle Ve is released, the vehicle Ve starts to be started by the driving force transmitted from the engine 1. Thereafter, this routine is once terminated.

  When the present invention is applied to the two-wheel drive vehicle Ve ′, the braking force applied to the non-drive wheels 9 ′, 10 ′ or all the wheels 9 ′, 10 ′, 14 ′, 15 ′ can be maintained. The state is released. Then, when the braking force of the vehicle Ve is released, 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 braking force applied to the driven wheels 9, 10 or all the wheels 9, 10, 14, 15 when the driving torque increased when the vehicle Ve starts is larger than the reference value β. Even if the holding state is released, when the vehicle Ve is moved by the above-described moving force, that is, when the vehicle Ve stops in the middle of the slope, for example, the vehicle Ve moves down the slope due to the action of gravity. In that case, the holding state of the braking force applied to the driven wheels 9, 10, or all the wheels 9, 10, 14, 15 is released. The start of the vehicle Ve is started.

  Further, when the present invention is applied to the two-wheel drive vehicle Ve ′, the non-drive wheels, that is, the left and right front wheels 9 are increased when the drive torque increased when the vehicle Ve ′ starts is greater than the reference value β. Even if the holding state of the braking force applied to ', 10' or all the wheels 9 ', 10', 14 ', 15' is released, the vehicle Ve 'can be moved by the moving force as described above. In this case, the holding state of the braking force applied to the non-drive wheels 9 ′, 10 ′ or all 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 the braking force control for maintaining the stop state is executed when the vehicles Ve and Ve ′ are stopped, for example, the vehicles Ve and Ve ′ are stopped on the uphill road. The slope of the road surface when it is When the road surface inclination angle is smaller than a predetermined reference value α, that is, the moving force acting on the vehicles Ve and Ve ′ is small, and a relatively large braking force is required to counter the moving force. If not, wheels having a large driving force transmitted from the engine 1 to the wheels 9, 10, 14, and 15, that is, the left and right rear wheels 14 and 15 that are main driving wheels, or the left and right rear wheels 14 that are driving wheels. ', 15' is not braked, but the wheels having a small driving force, that is, the left and right front wheels 9, 10 which are driven wheels or the left and right front wheels 9 ', 10' which are non-driving wheels are braked. That is, the braking force is applied only to the slave driving wheels 9 and 10 or the non-driving wheels 9 'and 10' having a small driving force. In other words, the stopping state of the vehicles Ve and Ve 'is maintained by applying the braking force only to the slave driving wheels 9 and 10 or the non-driving wheels 9' and 10 'having a small driving force.

  Further, when the vehicle Ve, Ve ′ is started, when the driving force transmitted from the engine 1 to the wheels 9, 10, 14, 15 is smaller than the reference value β, that is, the road surface inclination angle as described above. When the moving force is smaller than the correlated moving force, the main driving wheels 14 and 15 or the driving wheels 14 'and 15' having a large driving force are not braked and the slave driving wheels 9 and 10 or the non-driving wheels having a small driving force. 9 'and 10' are braked. That is, the state in which the braking force is applied only to the driven wheels 9 and 10 having a small driving force or the non-driving wheels 9 'and 10' is continued. In other words, when the vehicles Ve and Ve ′ are started, the braking force is applied to the driven wheels 9 and 10 having a small driving force or the non-driving wheels 9 ′ and 10 ′ until the driving force is increased beyond the moving force. As a result, the stopped state of the vehicles Ve and Ve ′ is maintained.

  Therefore, compared to, for example, a case where control is performed so that braking force is applied to all wheels, the content of the braking control and the configuration for executing the control can be simplified, and the braking control can be executed easily. In addition, when starting the vehicles Ve and Ve ′, it is possible to avoid the occurrence of so-called brake dragging on the main driving wheels 14 and 15 or the driving wheels 14 ′ and 15 ′ having a large driving force, and to reduce brake wear. Can do.

  When the moving force is greater than or equal to a predetermined reference value α, that is, the moving force acting on the vehicles Ve and Ve ′ is large, and a relatively large braking force is required to counter the moving force. In this case, the main driving wheels 14 and 15 or the driving wheels 14 'and 15' having a large driving force are braked in addition to the slave driving wheels 9 and 10 or the non-driving wheels 9 'and 10' having a small driving force. . That is, braking force is applied to all wheels. Therefore, even when the moving force is large and the vehicles Ve and Ve ′ may be moved by the moving force, the braking force is applied to all the wheels, so that the ground contact area with respect to the road surface of the braked wheels is increased. Can be increased to increase the braking force of the vehicles Ve and Ve ′. As a result, the stopped state of the vehicles Ve and Ve ′ can be more reliably maintained.

  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. Further, the second control example shown in the flowchart of FIG. 2 is obtained by partially changing the control contents in the first control example shown in the flowchart of FIG. Therefore, steps having the same control contents are denoted by the same step numbers as the step numbers given in the flowchart of FIG.

  In the first control example shown in the flowchart of FIG. 1 described above, the vehicle Ve in the present invention is described as a control example when applied to the four-wheel drive vehicle Ve or the two-wheel drive vehicle Ve ′. Of these, when the two-wheel drive vehicle Ve ′ is the target of control, the frequency of traveling on a climbing road with a large road surface inclination angle close to the limit of the climbing ability of the vehicle Ve, or stopping on such a climbing road, or It can be assumed that the possibility is relatively low compared to the case of the four-wheel drive vehicle Ve. Therefore, in the second control example shown in the flowchart of FIG. 2, the control content in the first control example shown in the flowchart of FIG. Can be easily executed.

  That is, in FIG. 2, as in the case of the first control example shown in the flowchart of FIG. 1 above, when the vehicle Ve ′ is in the stopped state and a positive determination is made in step S1, the process proceeds to step S21. Then, the braking force is applied to the non-driving wheels, that is, the left and right front wheels 9 ′, 10 ′ without applying the braking force to the driving wheels, that is, the left and right rear wheels 14 ′, 15 ′, and the braking force is maintained.

  Then, similarly to the case of the first control example, the control of the subsequent steps S6 to S8 is executed, and in step S8, a positive determination is made in step S8 because the drive torque is larger than the reference value β. Then, the process proceeds to step S22, and the holding state of the braking force applied to the non-driving wheels 9 ′ and 10 ′ is released. When the braking force of the vehicle Ve ′ is released, the vehicle Ve ′ starts to be started by the driving force transmitted from the engine 1. Thereafter, this routine is once terminated.

  That is, even when the holding state of the braking force applied to the non-driving wheels 9 ′ and 10 ′ is canceled when the driving torque that is increased when the vehicle Ve ′ starts is larger than the reference value β, Since it can be determined that the vehicle Ve ′ is not moved by the moving force as described above, the holding state of the braking force applied to the non-driving wheels 9 ′ and 10 ′ is released in that case. Then, the start of the vehicle Ve ′ is started.

  By executing the control as described above, as in the case of the first control example, for example, the control becomes complicated compared to the case where the control is performed so as to apply the braking force to all the wheels. The braking force control can be executed more easily. Further, when the vehicle Ve ′ is started, it is possible to avoid the occurrence of so-called brake dragging on the drive wheels 14 ′ and 15 ′ to which all driving force is transmitted, and to reduce brake wear.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means of steps S3 to S8 and steps S21, S6 to S8 described above correspond to the braking force control means of the present invention. The functional means in step S2 corresponds to the moving force calculating means of the present invention, and the functional means in step S8 corresponds to the driving force calculating means of the present invention. Further, the functional means of steps S3 and S4 correspond to the means for braking the wheel having a small driving force without braking the wheel having a large driving force in claim 2 of the present invention, and the functional means of steps S3 and S5. Corresponds to means for braking a wheel having a large driving force in addition to a wheel having a small driving force in the third aspect of the present invention. The functional means of steps S7 and S8 correspond to means for braking a wheel having a small driving force without braking a wheel having a large driving force in claim 4 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 wheel operates the wheel 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 inclination angle 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 surface inclination angle 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 (5)

The braking control apparatus for a vehicle which controls 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 to act before Symbol vehicle,
If the moving force calculated by the moving force calculating means is smaller than a predetermined reference value, the stop state of the vehicle prior from the dynamic force source to the starting of the vehicle by the driving force transmitted to the wheels Brake control for a vehicle, comprising braking force control means for controlling the braking force for maintaining the vehicle by braking the wheel with the small driving force without braking the wheel with the large driving force. apparatus. Before SL braking force control unit, when the moving force calculated by the moving force calculating means is a predetermined reference value or more, braking large wheels of the driving force in addition to a small wheel of said driving force The vehicle braking control device according to claim 1, further comprising: Further comprising a driving force calculating means for calculating a pre-Symbol driving force,
Said braking force control means, upon starting of the vehicle by the front Symbol driving force, when the driving force calculated is smaller than the moving force calculated by the moving force calculation means by the driving force calculating means, wherein 2. The vehicle braking control apparatus according to claim 1, further comprising means for braking the wheel having the small driving force without braking the wheel having the large driving force . Features large wheels of the driving force is a driving wheel of the driving force from the power source is transmitted, a small wheel of the driving force, and this is a non-driving wheel, wherein the driving force is not transmitted from the power source The vehicle braking control device according to any one of claims 1 to 3 . Large wheels of the driving force, the a main drive wheel driving force is relatively large for a power source or, et al is transmitted, a small wheel of the driving force, the driving force transmitted from the power source is a relative brake control apparatus for a vehicle according to any one of claims 1 to 3, characterized in that to a small sub-drive wheels.

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