JP2001039291A - Automobile braking system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent degradation in vehicle braking performance and directional stability as well as discomfort or poorly experienced braking force just before a vehicle stop within braking systems that effect, typically, ABS control to prevent all wheels from locking by braking and select-low correction on the ABS control while a spare tire is mounted, by obviating such erroneous detection of a spare-tire-mounted wheel as results from, for instance, wheelspins of the driving wheels on a low-friction road surface. SOLUTION: If the deviations in speed of all wheels from one another are continuously on a small level, the detection result of spare-tire-mounted wheels is reset in SD13, SD14. The time to determine the small deviation state is set longer in SD17 for a driven wheel detected as the spare-tire-mounted wheel than for a driving wheel, and further longer in SD19 if the vehicle runs on a low-friction-coefficient road as well as at low speed. If the vehicle is in an extremely low-speed travel state typically just before a stop on a low-friction- coefficient road surface, select-low correction is disabled to put the right and left wheels under individual ABS control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antiskid brake system (hereinafter referred to as A) for controlling a braking force so that each wheel of a vehicle is not locked.
(Referred to as a BS device).

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. Hei 4-21845.
As disclosed in Japanese Patent Application Publication No. 3 (1999) -2003, there is known an automobile braking device which performs anti-skid control for preventing a brake lock of each wheel of a vehicle. In this vehicle, a wheel speed sensor is provided for each wheel of a vehicle, and a vehicle speed is estimated and calculated based on the rotation speed of each wheel detected by the sensor. Then, the estimated vehicle speed and the rotational speed of each wheel are individually compared to detect the slip state of each wheel, and the following anti-skid control is performed for each wheel according to the slip state. ing.

That is, for example, a wheel slip amount at which a wheel exerts a maximum braking force is set as a target value,
When the slip amount of each wheel exceeds the control start threshold value, the anti-skid control is started, and the brake fluid pressure in the wheel cylinder of each wheel is controlled by increasing, holding, or reducing the pressure. By doing so, the wheel slip amount is made to converge on the target value.

In recent years, small-diameter and narrow-width tires, such as mini tires and tempered tires, have become widespread as spare tires for use in vehicles. Since the wheel speed (rotation speed) is higher than that of the wheels, there is a possibility that erroneous anti-skid control may be performed. Thus, for example, in the vehicle disclosed in Japanese Patent Application Laid-Open No. 9-76889, the vehicle speed of one of the four wheels is kept higher than that of the other wheels continuously for a predetermined time or more while the vehicle is running. At one time, it is detected that a spare tire is mounted on the wheel, and the detection value of the wheel speed sensor for this wheel is corrected.

[0005] Further, since the spare tire has a lower grip performance than the standard tire, generally, the braking force of another wheel adjacent to the wheel mounted on the spare tire in the left-right direction is determined by the braking force of the wheel mounted on the spare tire. By performing select low correction that suppresses the braking force to be approximately the same as the braking force that can be exerted, the braking force acting on each of the left and right sides of the vehicle body is made substantially the same, and the directional stability of the vehicle at the time of braking is improved We are trying to secure.

[0006]

However, the detection of a wheel mounted with a spare tire as disclosed in the latter conventional example,
Depending on the running condition of the vehicle and the condition of the running road surface, it must be considerably inaccurate. For example, since the drive wheels are likely to spin on a so-called low μ road surface, when a spare tire is mounted on one of the two driven wheels of the vehicle, the wheel speed of the spare tire mounted wheel and the two wheels that are spinning are In some cases, the wheel speeds of the drive wheels become substantially the same, and the installation of the spare tire is not detected. In this case, the wheel speeds of the spare tire-mounted wheels are used for estimation calculation of the vehicle speed without any correction, so that the estimated vehicle speed is shifted to a higher one, and the wheel slip amounts of all four wheels are apparent. As a result, the anti-skid control is erroneously started early and the braking distance of the vehicle is unduly increased.

Further, if an erroneous determination is made that the spare tire is not mounted in spite of the fact that the spare tire is mounted as described above, the select row correction corresponding to the mounting of the spare tire is not performed. As a result, the braking force of the spare tire is significantly different from the braking force of the standard tire, and a large yaw moment acts on the vehicle body during braking, so that directional stability may be impaired.

On the other hand, if the selection of the spare tire is correctly detected and the select-low correction is performed in response to this, it is possible to prevent the directional stability from being impaired at the time of braking as described above. In some cases, the driver of the vehicle may feel uncomfortable. That is, for example, when stopping a running vehicle, the traveling speed is usually reduced sufficiently to just before a target stop position to bring the vehicle to an extremely low-speed traveling state (for example, a traveling state of 10 km / h or less). The operation of stopping the vehicle by pressing the brake strongly just before the position is performed, but if the spare tire is mounted, the anti-skid control is started when the last strong brake operation is performed At the same time, the select-low correction is performed, and an uncomfortable feeling such that the braking force is released with respect to the last brake operation occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to perform anti-skid control for preventing brake lock of each wheel of a vehicle and to mount a small-diameter spare tire. When the vehicle is in a certain running state, the braking device corrects the anti-skid control in response to the detection procedure of a wheel mounted with a spare tire and a correction procedure corresponding thereto. By taking special measures, it is possible to prevent a reduction in braking performance and directional stability due to erroneous anti-skid control due to erroneous detection, and also to prevent a driver from feeling uncomfortable.

[0010]

In order to achieve the above-mentioned object, according to a first solution of the present invention, in order to prevent erroneous detection of a wheel on which a spare tire is mounted, a deviation amount of rotation speed between respective wheels is reduced. When it is determined that the small deviation state has continued for a set time or more, the detection result of the wheel mounted with the spare tire is reset, and the time for the determination is determined by determining whether the wheel mounted with the spare tire is a driving wheel or a driven wheel. Changed settings depending on whether or not.

More specifically, FIG.
As shown in the figure, a braking means 60 for applying a braking force to each wheel of the vehicle, a rotation speed detecting means 210 for respectively detecting the rotation speed of each wheel, and a detection by the rotation speed detecting means 210 during braking of the vehicle. Anti-skid control means 20a for controlling the operation of the braking means 60 based on the values so that the slipping state of each wheel converges to a predetermined target state by the braking force applied to each wheel; Spare wheel mounting wheel detecting means 20c for detecting a wheel on which a spare tire smaller in diameter than the standard tire is mounted, based on the detection value of the standard tire, and the spare wheel mounting wheel detecting means 20c detects the wheel mounted with the spare tire. When the anti-skid control means 20a corrects the control of the braking means 60 by the anti-skid control means 20a based on the detection result. A braking device A of a motor vehicle and a means 20d is assumed. And the rotation speed detecting means 2
The rotational deviation state determining means 2 for determining that the rotational velocity deviation amount between the wheels is a small deviation state that is continuously equal to or less than a predetermined amount for a set time or more based on the detection value obtained by the control unit 10.
0f, a detection result resetting means 20g for resetting the detection result by the spare tire mounted wheel detecting means 20c when the rotational deviation state determining means 20f determines that it is in the small deviation state, and the rotational deviation state determining means 20f.
And a judgment time setting means 20h for setting the judgment time of the small deviation state to be longer when the mounting wheel of the spare tire is the driven wheel of the vehicle than when it is the driving wheel.

With the above structure, when a spare tire having a small diameter is mounted on any one of the wheels of the vehicle, the rotational speed of the wheel provided with the spare tire is generally higher on average than the other wheels. Based on the value detected by the rotational speed detecting means 210,
By 0c, a spare tire mounting wheel is detected. And
Based on this detection result, anti-skid control correcting means 2
By correcting the control of the braking means 60 by the anti-skid control means 20a (hereinafter, also simply referred to as anti-skid control) by 0d, erroneous anti-skid control due to mounting of a spare tire is suppressed as in the related art. can do. On the other hand, if the detection of the spare tire-mounted wheel is erroneous, the rotation speed of each wheel is essentially the same. When the rotation is continued, it is determined by the rotational deviation state determining means 20f that the rotational speed of each wheel is in a small deviation state, and the detection result by the spare tire mounting wheel detecting means 20c is the detection result resetting means 2
Reset by 0g. Thereby, erroneous detection of the spare tire mounting wheel can be reduced.

Further, when it is detected that the spare tire is mounted on the driven wheel of the vehicle, the determination time setting means 2
0h is set so that the determination time of the small deviation state becomes longer. As a result, even if the driving wheel spins and the rotation speed of the driving wheel is substantially the same as the rotation speed of the wheel mounted with the spare tire, such a state does not continue so long. It is possible to prevent the detection result of the wheel mounted with the spare tire from being erroneously reset due to the wheel spin. That is, according to this configuration, it is possible to increase the detection accuracy of the wheel on which the spare tire is mounted, so that it is possible to prevent a decrease in the braking performance and directional stability of the vehicle due to erroneous detection.

According to a second aspect of the present invention, the determination time setting means sets the determination time to be long only when the friction coefficient of the road surface on which the vehicle runs is a low μ road substantially equal to or less than a predetermined value. And

[0015] As a result, the drive wheel tends to spin on a low μ road, and if a spare tire is mounted on a driven wheel, there is a high possibility that the detection result of the mounting is erroneously reset. In an appropriate running state, the determination time of the small deviation state is set to be long so that the determination accuracy can be sufficiently increased. On the other hand, since there is a low possibility that the reset is performed erroneously on a road other than the low μ road as described above, the shorter the determination time, the better the determination accuracy.

According to the third aspect of the invention, the determination time setting means sets the determination time to be long only when the traveling speed of the vehicle is lower than a predetermined speed. As a result, it is rare for the drive wheels to spin when the vehicle is running at medium to high speeds. Therefore, the determination time for the small deviation state is set to be long only when the vehicle is running at low speed, and the determination accuracy is sufficiently increased. be able to.

In the invention according to claim 4, the determination time setting means sets the determination time longer when the vehicle is in a turning state than when the vehicle is not turning. With this,
During the turning of the vehicle, the wheel speeds of the turning inner wheel and the turning outer wheel are naturally different from each other, and the side wheels act on the tires, so that the driving wheels are particularly likely to cause wheel spin.
Therefore, in such a state, the determination accuracy of the small deviation state can be further improved by setting the determination time of the small deviation state particularly long.

In the invention of claim 5, the determination time setting means sets the determination time longer as the traveling speed of the vehicle is lower. For this reason, for example, on a low μ road or the like, the lower the traveling speed of the vehicle, the longer the wheel spin of the drive wheels tends to last. Therefore, the lower the traveling speed of the vehicle, the longer the determination time of the small deviation state is set. Thereby, the determination accuracy can be further increased.

Next, in a second solution of the present invention, when the driver performs a brake operation while the vehicle is running at an extremely low speed, the vehicle is designed to prevent the driver from feeling uncomfortable that the braking force is released. When the vehicle is traveling at an extremely low speed, the select skid correction of the anti-skid control is suppressed.

More specifically, FIG.
As shown in the figure, a braking means for applying a braking force to each wheel of the vehicle, and the braking so as to converge the slip state of each wheel to a predetermined target state by the braking force applied to each wheel during braking of the vehicle. An anti-skid control means 20a for controlling the operation of the means 60; a spare tire mounting wheel detecting means 20c for detecting a wheel on which a spare tire smaller in diameter than the standard tire is mounted from among the wheels; An anti-skid control correcting means for correcting the control of the braking means by the anti-skid control means based on the detection result when the wheel detection means detects a wheel to which a spare tire is mounted; Device A is assumed. The anti-skid control correcting means 20d is adapted to apply an anti-skid control means such that a braking force substantially the same as a braking force applied to a wheel mounted with a spare tire is also applied to other wheels adjacent to the wheel in the left-right direction. The control of the braking means 60 by 20a is to be selected low corrected, and when the vehicle is in a predetermined extremely low speed running state and the wheel mounted with the spare tire is a driven wheel of the vehicle,
Select row correction suppressing means 20e for suppressing select row correction by the anti-skid control correcting means 20d is provided.

With the above configuration, when a spare tire is mounted on any one of the wheels of the vehicle, the anti-skid control correcting means 20d applies a braking force substantially the same as the braking force applied to the spare tire mounted wheel. Select row correction is performed so as to add to other wheels adjacent to the wheel in the left-right direction. This makes it possible to apply a braking force having substantially the same magnitude to both the left and right sides of the vehicle body during braking, thereby ensuring directional stability. On the other hand, when the vehicle is in the predetermined extremely low-speed running state, the select-row correction is suppressed by the select-row correction suppressing means 20e, so that the other wheels adjacent to the spare tire mounting wheel exert a larger braking force. As a result, when the driver operates the brake, it is possible to reduce the discomfort that the braking force is released. At this time, although the braking forces on both the left and right sides of the vehicle body become unbalanced, there is no problem in the extremely low-speed running state because the vehicle stops before the vehicle body posture collapses.

According to a seventh aspect of the present invention, the vehicle travels at an extremely low speed of 10 km / h.
The following is assumed. Thus, the extremely low-speed running state of the vehicle is realized.

According to an eighth aspect of the present invention, the extremely low speed running state in the sixth aspect of the invention is set to a state immediately before the vehicle stops. Thus, when the driver performs the brake operation immediately before the stop of the vehicle, the select-low correction can be suppressed and the vehicle can be stopped promptly, and the discomfort that the braking force is lost can be reduced.

According to a ninth aspect of the present invention, the select-low correction suppressing means according to the sixth aspect of the present invention provides the anti-skid control only when the friction coefficient of the road surface on which the vehicle runs is a low μ road substantially equal to or less than a predetermined value. It is assumed that select row correction by the correction means is suppressed. That is, since the start of the anti-skid control during braking in an extremely low-speed running state is actually limited to the low μ road, the select low correction is suppressed only on the low μ road. The operation and effect can be sufficiently obtained.

According to a tenth aspect of the present invention, the select row correction suppressing means according to the sixth aspect of the present invention suppresses the select row correction by the anti-skid control correcting means only when the spare wheel is a driven wheel of the vehicle. It shall be. That is, if the wheels mounted on the spare tires are the driving wheels of the vehicle, the driving wheels are connected to the driving system and have a large rotational inertial force. Few. Therefore, by suppressing the select row correction only when the wheel on which the spare tire is mounted is a driven wheel, the operational effect of the invention of claim 6 can be sufficiently obtained.

In the eleventh aspect of the present invention, the select row correction suppressing means according to the sixth aspect of the present invention prohibits the select row correction by the anti-skid control correcting means, and the wheel mounted with the spare tire is adjacent to the left and right sides of the mounted wheel. It is assumed that the control of the braking means by the anti-skid control means is performed independently with respect to the other wheels.

As a result, the anti-skid control is performed independently for each of the left and right wheels, and both the wheel on which the spare tire is mounted and the other adjacent wheel exert the maximum braking force, respectively. It is possible to sufficiently enhance the performance and eliminate the feeling that the braking force is lost. Still further, according to the above configuration, for example, in a front-wheel drive vehicle, the right and left rear wheels, which are driven wheels, are integrally controlled in accordance with the lower braking force regardless of whether or not a spare tire is mounted. Also, when the vehicle is running at a very low speed and in the braking state, independent anti-skid control is forcibly performed on the left and right rear wheels including the wheels with spare tires, eliminating the feeling of loss of braking force can do.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows the overall structure of a vehicle braking device A according to an embodiment of the present invention. This braking device A is mounted on a so-called front wheel drive type vehicle that transmits driving force only to the left and right front wheels. .

In FIG. 3, 1 is a brake pedal 2
This is a master back that increases the treading pressure of the vehicle. Reference numeral 3 denotes a master cylinder which generates a brake hydraulic pressure (master cylinder pressure) in accordance with the pedaling pressure increased by the master back 1. The brake hydraulic pressure generated by the master cylinder 3 is two hydraulic pressures. AB which is conventionally known by supply lines 4 and 5
It is transmitted to a hydraulic distribution unit 6 (hereinafter referred to as HU) of the S device, distributed to four wheels (not shown) on the front, rear, left and right sides of the vehicle by the HU 6, and is provided with a brake device 7FR for the right front wheel and a left side. Front wheel brake device 7F
L, the brake device 7RR for the right rear wheel and the brake device 7RL for the left rear wheel. The HU 6 and four brake devices 7FR, 7F
L, 7RR, and 7RL constitute a braking means 60 for applying a braking force to each wheel of the vehicle.

The first hydraulic pressure supply line 4 of the two hydraulic pressure supply lines 4 and 5 is branched into a front wheel side and a rear wheel side in the HU 6, and the brake device 7FR for the right front wheel and the left rear wheel, respectively. Connected to the wheel brake device 7RL while the second
Similarly, the hydraulic pressure supply line 5 is branched and connected to the brake device 7FL for the left front wheel and the brake device 7RR for the right rear wheel, and the brake hydraulic piping is a so-called diagonal split type two-system piping. .

The HU 6 is connected to a hydraulic pressure supply line 4,
The four inlet valves 8, which are provided to individually switch the master cylinder 3 side and the brake devices 7FR, 7FL,... Side to the communication state or the cutoff state with respect to the five branch paths 4a, 4b, 5a, 5b, , 8 and 8, and the brake devices 7FR, 7FL,...
And four outlet valves 9, 9, 9, 9 for individually switching between the communication state and the cutoff state. Each of the inlet valves 8 is a normally open solenoid valve having two ports and two positions, and is switched between an open state and a closed state in response to a signal from the control unit 20, and each of the brake devices 7FR, 7FL,. The brake fluid pressure supplied from the master cylinder 3 to the wheel cylinder 7a is adjusted. Each of the outlet valves 9 is a normally closed solenoid valve having two ports and two positions, and is switched to an open state in response to a signal from the control unit 20 to bring the respective wheel cylinders 7a into communication with the reservoir tank 10. Thus, the brake fluid pressure (wheel cylinder pressure) of the wheel cylinder 7a is reduced.

Until the control signal output from the control unit 20 is inputted, the brake fluid pressure generated in the master cylinder 3 is opened according to the driver's depressing operation of the brake pedal 2, and the inlet valves 8, 8 in the open state are opened.
, Are supplied to the respective wheel cylinders 7a via the respective brake cylinders 8, and a braking force corresponding to the depression operation of the brake pedal 2 is applied to the respective wheels. When a control signal from the control unit 20 is input to the HU 6, the inlet valves 8, 8,... And the outlet valves 9, 9,.
The wheel cylinder pressure of FL,... Is increased or decreased, and the braking force applied to each wheel is adjusted.

Further, the HU 6 sucks the brake fluid discharged into the reservoir tanks 10 and 10 and supplies the brake fluid to the hydraulic pressure supply lines 4 and 5 upstream of the branch passages, respectively. , 12 are provided. Each of the hydraulic pressure supply pumps 12 is driven by an electric motor (not shown), and is stopped until a control signal output from the control unit 20 is input.
When the control signal is input, the operation is started and a brake fluid pressure higher than the master cylinder pressure is supplied to each wheel cylinder 7a. Incidentally, in FIG.
Reference numerals 1, 11, 11, and 11 denote bypass check valves that allow the flow of brake fluid from the wheel cylinder 7a to the master cylinder 3 when the respective inlet valves 8 are in the closed state. Reference numerals 13 and 13 denote check valves that allow the flow of brake fluid from the hydraulic supply pumps 12 to the hydraulic supply lines 4 and 5, respectively.
Reference numerals 14 and 14 denote accumulators for alleviating the pulsation of the hydraulic pressure supply pump 12, respectively.

Although not shown, the control unit 20 has a CPU, a ROM, a RAM, and the like, and wheel speed sensors 21, 21,... (Rotational speed detecting means) provided on four wheels of the vehicle, respectively. Only one is shown in the figure), a foot brake switch 22 (hereinafter referred to as FBSW) for detecting a depression operation of the brake pedal 2 of the vehicle, a steering angle sensor 23 for detecting a steering angle of the vehicle, and an engine for detecting an engine speed. Output signals from a rotational speed sensor 24, a gear position sensor 25 for detecting a gear position of the transmission, and a hydraulic pressure sensor 26 for detecting a brake hydraulic pressure (master cylinder pressure) of the master cylinder 3 are input. On the other hand, the control unit 20 includes an inlet valve 8 of the HU 6,
, And control signals are output to outlet valves 9, 9,.

That is, the control unit 20
As shown in the main flow of FIG. 4, when the driver gets into the vehicle and turns on the ignition key, at step SA1, at least the wheel speed sensors 21 and
1, ..., foot brake switch 22, steering angle sensor 2
3. The signals input from the engine speed sensor 24, the gear position sensor 25, and the hydraulic pressure sensor 26 are read, and in step SA2, the wheel speeds (wheel speeds) of the four wheels of the vehicle are averaged to obtain the vehicle speed. Is estimated.
When calculating the estimated vehicle speed V, the weights of the right and left rear wheels, which are driven wheels, may be increased, or the vehicle speeds of only the right and left rear wheels may be averaged.

Subsequently, in step SA3, anti-skid control (hereinafter referred to as ABS control) for controlling a braking force applied to each wheel so that the slip state of each wheel converges to a predetermined target state during braking of the vehicle. ) Is performed. In the following step SA4, rear wheel braking control (hereinafter, referred to as EBD control) for exerting the function of the proportioning valve by the distribution of brake fluid pressure to each wheel by the HU 6 is performed. That is, in response to the reduction of the rear wheel load due to the braking of the vehicle, the operation of the rear wheel side valves 8, 9 of the HU 6 is controlled to control the left and right rear wheel brake devices 7RR, 7RL.
To control the increase in the braking force of the rear wheel. Then, in step SA5, AB
The cooperative control of the S control and the EBD control is performed, and then the process returns.

In the main flow shown in FIG. 4, steps SA3 and SA4 are steps of the anti-skid control means 20a for performing ABS control and EBD control, respectively.
And the rear wheel braking control means 20b.

(ABS Control) Next, the ABS control will be described in detail with reference to the flowchart shown in FIG. In step SB1 of the figure, the presence or absence of a foot brake operation by the driver is determined based on the output signal from the FBSW 22, and if it is determined that the brake operation has not been performed NO, the process proceeds to step SB2 to execute the ABS control. The value of the ABS flag Fslip that indicates whether the vehicle is in the middle or not is set to Fslip = 0.
Then, in subsequent step SB3, each inlet valve 8 is opened and each outlet valve 9 is closed, and then the process returns.

On the other hand, if it is determined in step SB1 that the brake operation has been performed, the process proceeds to step SB4.
To calculate a wheel slip ratio based on the wheel speed and the vehicle speed V for each wheel.

Wheel slip ratio = (V-wheel speed) / V Subsequently, in step SB5, the road surface friction coefficient μ is estimated and calculated by a conventionally known method based on the wheel slip ratio of each of the four wheels and the master cylinder pressure. In step SB6, a target slip ratio sb, which is a control target value of the wheel slip ratio, and a control start threshold value sa are calculated based on the estimated value of the road surface friction coefficient μ. The wheel slip ratio may be detected by a longitudinal acceleration sensor mounted on the vehicle, or may be indirectly obtained from a road surface friction coefficient μ or the like, in addition to the calculation as described above.

Following the step SB6, a step S6 is executed.
In C7 to SC15, the brake fluid pressure of each wheel is increased,
Hold or reduce pressure. This control of the brake fluid pressure is performed independently for the left and right front wheels that are the driving wheels of the vehicle, while the integrated control is performed so that the left and right rear wheels that are the driven wheels have the same brake fluid pressure. The directional stability during braking on a split road or the like can be ensured.

Specifically, first, at step SB7, AB
The value of the S flag Fslip is determined, and if NO of Fslip = 1, the ABS control is already being performed, and the process proceeds to step SB10.
If YES in Fslip = 0, it means that the ABS control is not being performed, so the process proceeds to step SB8, where the wheel slip ratio is compared with a control start threshold value sa. If the wheel slip rate is NO equal to or less than the control start threshold value sa, the process returns. If YES is larger than the control start threshold value sa, the process returns to step S.
Proceeding to B9, the value of the ABS flag Fslip is set to Fslip = 1, and then proceeding to steps SB11 to SB13 to control the opening and closing of the inlet valves 8, 8,... And the outlet valves 9, 9,.

On the other hand, in step SB10, in which it is determined that Fslip = 1 in step SB7, the wheel slip ratio is compared with the target slip ratio sb, and if the wheel slip ratio is equal to or smaller than the target slip ratio sb, the process proceeds to step SB10. SB1
YES while being larger than the target slip ratio sb
If so, the process proceeds to Step SB11. This step SB11
Then, the wheel acceleration obtained by differentiating the wheel speed is compared with a predetermined pressure reduction threshold value sk1, and if the wheel acceleration is larger than the pressure reduction threshold value sk1, YES, Step SB1
Proceeding to 2, the inlet valve 8 and the outlet valve 9 are both closed to bring the wheel cylinder pressure into a holding state. If the wheel acceleration is NO equal to or less than the pressure reduction threshold value sk1, the process proceeds to Step SB13, in which the inlet valve 8 is closed and the outlet valve 9 is opened to reduce the wheel cylinder pressure. .

That is, while the wheel slip rate is greater than the target slip rate sb, the wheel cylinder pressure is reduced while switching between the reduced pressure state and the holding state according to the wheel acceleration, thereby preventing the wheels from being locked. Like that. The brake fluid discharged from the outlet valve 9 to the reservoir tank 10 in this reduced pressure state is immediately sucked by the hydraulic pressure supply pump 12 and supplied to the hydraulic pressure supply lines 4 and 5.

On the other hand, in step SB14, in which the wheel slip rate is determined to be NO equal to or less than the target slip rate sb in step SB10, the wheel acceleration is compared with a predetermined pressure increase threshold sk2, and the wheel acceleration is increased. If YES is larger than the pressure threshold value sk2, the process proceeds to Step SB15, in which the inlet valve 8 is opened and the outlet valve 9 is closed, and the wheel is supplied by the hydraulic pressure from the master cylinder 3 and the hydraulic pressure supply pump 12. The pressure is increased to increase the cylinder pressure. If the wheel acceleration is equal to or less than the pressure increase threshold value sk2, the process proceeds to step SB16, where both the inlet valve 8 and the outlet valve 9 are closed to maintain the wheel cylinder pressure.

That is, when the wheel slip rate is equal to or less than the target slip rate sb and there is room to increase the braking force, the wheel cylinder pressure is increased while switching between the holding state and the pressure increasing state in accordance with the wheel acceleration. The wheels are designed to provide maximum braking power.

(EBD Control) Next, the basic EBD control will be described with reference to the flowchart of FIG. 6. In step SC1 of FIG. 6, the foot brake operation by the driver is performed based on the output signal from the FBSW 22. It is determined whether or not the brake operation is not performed, and if it is determined that the brake operation is not performed, the inlet valves 8 and 8 of the left and right rear wheels are opened and the outlet valves 9 and
9 in a closed state (steps SC2 and SC3), and in a subsequent step SC4, EB indicating whether or not the EBD control is being executed.
The value of the D flag FEBD is set to FEBD = 0, and thereafter, the process returns.

On the other hand, if it is determined in step SC1 that the brake operation has been performed, the process proceeds to step SC5.
Once, the inlet valves 8 and 8 of the left and right rear wheels are opened and the outlet valves 9 and 9 are closed. Subsequently, at step SC6, the current value is subtracted from the previous value of the vehicle speed V to obtain the vehicle deceleration, and the vehicle deceleration is compared with the deceleration set value B. If the answer is YES, the process proceeds to step SC8, while if the vehicle body deceleration is equal to or less than the deceleration set value B, the process proceeds to step SC7. In step SC7, wheel slip rates of the left and right rear wheels are calculated in the same manner as in step SB4 of the ABS control, and the wheel slip rate of one of the rear wheels is equal to or smaller than the start threshold sc of the EBD control. If so, the process proceeds to step SC10, while the threshold value sc is set.
If YES, the process proceeds to step SC8.

In step SC8, first, the inlet valves 8, 8 and the outlet valves 9, 9 of the right and left rear wheels are both closed, and the wheel cylinder pressure is basically maintained, so that the braking force of the rear wheels is maintained. To prevent the increase.
On top of that, in order to further enhance the braking performance while securing the straight running stability at the time of braking by increasing the grounding of the left and right rear wheels,
The inlet valves 8, 8 and the outlet valves 9, 9 are gradually opened and closed according to the wheel slip ratio and the wheel acceleration to slightly increase or decrease the wheel cylinder pressure. Then, the process proceeds to step SC9 to set the value of the EBD flag FEBD = 1 to FEBD = 1, and thereafter returns.

In step SC10, which was reached after the determination in step SC7 is NO, the EBD flag FEBD
If FEBD = 0 and YES, it is determined that the vehicle body deceleration is still equal to or less than the set deceleration B or that the driver has stopped the foot brake operation, and the routine returns. If NO in step SC1, the flow advances to step SC8 to perform control for maintaining the wheel cylinder pressure, and thereafter returns.

That is, according to the EBD control, for example, as shown by a solid line a in FIG. 7, first, the braking force of the left and right rear wheels is linearly increased in the same manner as the front wheels. Around the ideal braking force distribution curve shown,
Specifically, when the vehicle body deceleration becomes larger than the deceleration set value B or the wheel slip ratio becomes larger than the threshold value sc (break point S), the brake fluid pressure of the left and right rear wheels is increased. Is basically maintained, so that the braking force is substantially ideally distributed to the four front, rear, left and right wheels. In this case, while the brake fluid pressure is basically maintained as described above, the pressure is slightly increased or decreased according to the slip ratio of each wheel, so that the proportion indicated by a broken line c in FIG. Compared with the characteristics of the ning valve, the braking force can be greatly increased without inducing the rear wheel brake lock.

In step SC6, the vehicle body deceleration is obtained based on the vehicle speed V. However, the present invention is not limited to this, and the vehicle deceleration may be obtained from the wheel speed.
A longitudinal acceleration sensor may be mounted on the vehicle to directly detect the acceleration. Further, the value thus obtained may be corrected based on the road surface friction coefficient μ, the ground contact load of each wheel, and the like.

(Temperature Tire Mounting Determination and ABS Correction Control) In this embodiment, as a feature of the present invention, when a temper tire (spare tire) is mounted on one of the front, rear, left and right wheels of the vehicle, Then, the ABS control and the EBD control are corrected. That is, since the tempered tire has a smaller width and a smaller diameter than the standard tire, the wheel equipped with the tempered tire has a higher wheel speed and a considerably lower grip force than other wheels.

Next, the processing procedure of the ABS correction control corresponding to the detection of the mounting wheel of the spare tire and the detection result will be described with reference to the flowcharts shown in FIGS.

First, in step SD1 of FIG. 8, it is determined whether or not the value of a tempered tire flag Ft indicating that a tempered tire is mounted is 1, and Ft = 1.
Then, if it is determined that the tempered tire is mounted is YES, the process proceeds to step SD7, while if it is determined that Ft = 0 and NO is that the tempered tire is not mounted, the process proceeds to step SD2. In this step SD2, 4
It is determined whether the wheel speed of any one of the wheels is higher than the other three wheels. If the determination result is NO, the process proceeds to step SD4 to perform normal ABS control, and thereafter returns. On the other hand, the determination result is YES
If so, the process proceeds to step SD3, where it is determined whether or not the predetermined time has elapsed. If the predetermined time has not elapsed, the process returns to step SD2. If the predetermined time has elapsed (YES in step SD3). The process proceeds to step SD5.
That is, when one of the wheel speeds is higher than the other three wheel speeds on average, it is detected that a tempered tire is mounted on the wheel.

In step SD5 where the detection of the mounting of the tempered tire proceeds as described above, first, a vehicle speed calculation correction for excluding the wheel speed of the wheel mounted with the tempered tire from the calculation of the estimated vehicle speed V is performed. . As a result, even if the wheel speed of the wheel on which the tempered tire is mounted apparently increases, it is possible to prevent the estimated vehicle speed V from becoming higher than the actual value. Secondly, in order to match the braking force that the tempered tire can exert, the ABS control select law is to reduce the brake fluid pressure to the wheel mounted on the tempered tire and other wheels adjacent to the left and right direction. Make corrections. This prevents different braking forces from acting on the left and right sides of the vehicle body while preventing the brake lock of the tempered tire-mounted wheels, thereby ensuring the directional stability of the vehicle. Then, in step SD6 following step SD5, the temper tire flag Ft is set to 1, and the process returns after a while.

On the other hand, in step SD1, it is determined that the mounting of the tempered tire has already been detected (Ft = 1), and in step SD7, which is proceeded, it is determined whether or not the detection result of the wheel mounted with the tempered tire is correct. That is, in this step SD7, it is determined whether or not any deviation amount of any two of the four wheels of the vehicle is equal to or less than a predetermined amount. And
If the determination result is YES and the deviation amounts of the wheel speeds between the respective wheels are all equal to or less than the predetermined amount, the detection result of the wheel equipped with the tempered tire may be erroneous.
On the other hand, if the result of the determination is NO, the detection result of the wheel mounted with the temper tire is determined to be correct, and the flow proceeds to step SD8.

Subsequently, in step SD8, it is determined whether or not the vehicle is traveling on a low μ road based on the road friction coefficient μ estimated and calculated by the ABS control in FIG. 5, and in subsequent step SD9 Then, it is determined whether or not the traveling speed of the vehicle is an extremely low speed traveling state of, for example, 10 km / h or less. If NO is determined in one of steps SD8 and SD9, the process proceeds to step SD5, in which the vehicle speed calculation correction and the select low correction are performed. If the vehicle is traveling at extremely low speed on a low μ road, step SD1
Proceeding to 0, the select row correction is prohibited, and the ABS control is independently performed on both the wheel on which the tempered tire is mounted and the other wheel adjacent to the wheel in the left-right direction.

Incidentally, if the tempered tire is mounted on the rear wheel which is a driven wheel of the vehicle, the ABS control for the right and left rear wheels is essentially the same brake fluid pressure even if the select low correction is prohibited. The integrated control is performed as described above, but in step SD10, independent ABS control is performed for the left and right rear wheels forcibly.

That is, when a tempered tire is mounted on one of the four front, rear, left and right wheels of the vehicle and the vehicle has a low μ
For example, if the vehicle is in a very low speed running state immediately before stopping on the road, the select low correction corresponding to the mounting of the tempered tire is prohibited, and the ABS control is forcibly set to the independent control for the left and right wheels, so that the The vehicle can be stopped quickly by exerting the maximum braking force on each of the mounted wheel and other wheels adjacent to the wheel in the left-right direction. At this time, an unbalanced braking force acts on both the left and right sides of the vehicle body, and a yaw moment is generated.
There is no problem because the vehicle stops before the posture of the vehicle collapses.

Step SD2 of the flow shown in FIG.
A spare tire mounted wheel detecting means 20 for detecting a wheel on which a temper tire smaller in diameter than the standard tire is mounted on the basis of a value detected by the wheel speed sensor 21 by SD3.
c is configured. Also, by step SD5,
Anti-skid control correcting means 20d for correcting the ABS control based on the detection result when the spare tire mounted wheel detecting means 20c detects the mounted wheel of the tempered tire is configured.
0d excludes the tempered tire-mounted wheel from the calculation of the estimated vehicle speed V, and applies the same braking force to the other wheel adjacent to the mounted wheel in the left-right direction as the braking force applied to the tempered tire-mounted wheel. Thus, the ABS control is configured to perform select low correction.

Further, at step SD10, when the vehicle is traveling on a low μ road and in a predetermined extremely low speed traveling state, the select low correction by the anti-skid control correction means 20d is prohibited, and the left and right independent ABS are controlled. A select row correction suppressing unit 20e for performing control is configured.

In step SD7 of the flow shown in FIG. 8, it is determined that the deviation amount of the wheel speed between the wheels is less than a predetermined amount, and that the detection result of the wheel with the tempered tire may be erroneous. When the determination is made, the process proceeds to step SD11 of the flow shown in FIG.
At 11, it is determined whether or not the tempered tire mounting wheel is a driven wheel of the vehicle. When the result of the determination is YES and it is detected that the tempered tire is mounted on the driven wheel, the process proceeds to step SD15, while the result of the determination is NO and it is detected that the tempered tire is mounted on the driving wheel of the vehicle. At step SD12, it is determined whether or not the set time T0 (for example, about 1 second) has elapsed in a state where the deviation between the wheel speeds is small. If the set time T0 has not elapsed, the process returns to step SD7 in FIG. 8, while if the set time T0 has elapsed (step SD12).
Then, the process proceeds to steps SD13 and SD14 to reset the detection result of the mounting of the tempered tire (Ft ←).
0), normal ABS control is performed.

Further, in step SD15, where it is determined in step SD11 that the wheel to which the tempered tire is mounted is the driven wheel of the vehicle is determined to be YES, the process proceeds to step SD15.
It is determined whether or not the vehicle is on a low μ road in the same manner as in step 8. Then, in step SD16, it is determined whether or not the vehicle is in a low-speed running state at a predetermined speed or less (for example, 40 km / h or less). If NO is determined in one of steps SD15 and SD16, the process proceeds to step SD17 to determine whether or not a set time T1 (T1> T0) has elapsed.
If the set time T1 has not elapsed, the process returns to step SD7 in FIG. 8, while if the set time T1 has elapsed (YES in step SD17), the process proceeds to steps SD13 and S13.
Proceeding to D14, the detection result of the mounting of the temper tire is reset (Ft ← 0), and normal ABS control is performed.

On the other hand, if YES is determined in both steps SD15 and SD16, that is, if the vehicle is running at a low speed on a low μ road, the process proceeds to step SD18, and this time the steering angle sensor Based on the signal from 23, it is determined whether or not the vehicle is turning. If the determination result is NO and the vehicle is not turning, the process proceeds to step SD19 to determine whether or not the set time T2 (T2> T1) has elapsed, while if the determination result is YES and the vehicle is turning. For example, the process proceeds to step SD20 to determine whether or not the set time T3 (T3> T2) has elapsed. In both of steps SD19 and SD20, if NO is determined that the set time has not elapsed, the process returns to step SD7 in FIG. 8, while if YES is determined that the set time has elapsed, the process proceeds to steps SD13 and SD14 to attach the tempered tire. Is reset (Ft ← 0), and normal ABS control is performed.

In short, when it is detected that the tempered tire is mounted on the driven wheel of the vehicle, the small deviation state determination times T1 to T3 for resetting the detection result are set.
When the tempered tire is mounted on the drive wheel (T
0), and especially when the vehicle is on a low μ road and running at low speed,
Set the set time sufficiently long (T2). With this,
When the vehicle is running on a low μ road and running at low speed, the drive wheels spin and the error in resetting the detection results of the wheels with tempered tires is likely to be incorrect. By doing so, an erroneous reset can be prevented. Further, during the turning of the vehicle, the wheel spin of the drive wheel is more likely to occur, so in order to cope with this, the determination time is set longer (T3).

Step SD1 of the flow shown in FIG.
In each of steps SD2, SD17, SD19, and SD20, the determination is NO, and the process returns to step SD7 in FIG.
The control procedure of determining again whether the deviation of the wheel speed between the wheels is equal to or less than a predetermined value is based on the signal of the wheel speed sensor 21 when the deviation amount of each of the wheel speeds is any of the set times T0 to T
It corresponds to the rotation deviation state determination means 20f that determines that the state is a small deviation state of not less than 3 and not more than a predetermined amount continuously.

The steps SD12, SD17,
The control procedure in which each of the steps SD19 and SD20 is determined to be YES and the process proceeds to the step SD13 is such that when the rotational deviation state determining means 20f determines that the vehicle is in the small deviation state, the detection result by the spare tire mounting wheel detecting means 20c is obtained. Corresponds to the detection result resetting means 20g for resetting.

Further, steps SD11 to S
The control procedure to proceed to D15 is the rotation deviation state determination means 2
The determination time of the small deviation state based on 0f corresponds to the determination time setting means 20h that sets the time when the wheel to which the tempered tire is mounted is the driven wheel of the vehicle to be longer than that when the wheel is the driving wheel. And this determination time setting means 20h
Is configured to set the determination time longer when the vehicle is traveling at low speed on a low μ road than when it is not. Also, the configuration is such that the determination time is set longer during the turning of the vehicle. It should be noted that the determination time setting means 20h is set so that the lower the traveling speed of the vehicle is,
The determination time may be set to be long.

Therefore, according to the vehicle braking apparatus A of this embodiment, when the temper tire is mounted on any one of the wheels of the vehicle, the average value is obtained based on the value detected by the wheel speed sensor 21. It detects that a tempered tire is mounted on a wheel having a high wheel speed. Then, by excluding the wheel speed of the wheel with the tempered tire from the calculation of the estimated vehicle speed V, it is possible to prevent a problem of the ABS control due to the error of the estimated vehicle speed V. In addition, the select-low correction that reduces the braking force applied to the adjacent wheel in accordance with the mounting wheel of the tempered tire can prevent the left and right braking forces of the vehicle body from being different and impairing the directional stability.

The wheel speed of each wheel is monitored even after the detection of the wheel mounted with the temper tire, and when the state where the deviation of the wheel speed between the wheels is small continues for a set time or more (small deviation state). Since it is determined that the detection result of the wheel with the tempered tire is incorrect and the detection result is reset, it is possible to reduce the erroneous detection of the wheel with the tempered tire due to the road surface condition and the running state of the vehicle. it can.

Further, in this embodiment, the determination time of the small deviation state for resetting is changed and set depending on whether the tempered tire is mounted on the driving wheel or the driven wheel of the vehicle, and Since it is finely changed according to the road surface condition and the running condition of the vehicle, the reset can be performed with extremely high accuracy, and the detection accuracy of the wheel with the tempered tire is sufficiently high, which results in erroneous detection. It is possible to prevent a decrease in braking performance and directional stability of the vehicle.

Further, in this embodiment, even when the temper tire is actually mounted and the vehicle speed calculation correction and the select low correction are performed so as to correspond to this, the vehicle When the vehicle is traveling on a low μ road and in an extremely low speed traveling state such as before stopping, the select low correction is prohibited and the left and right wheels are forcibly subjected to independent ABS control so that the vehicle is quickly driven. , And the driver does not feel discomfort as if the braking force comes off.

In the above embodiment, the reset of the detection result of the wheel equipped with the tempered tire is determined based on the deviation state of the wheel speed between the wheels. Although the setting is changed depending on whether the vehicle is mounted on the drive wheel or the driven wheel, the change of the determination time is set only when the vehicle is traveling on a low μ road. Alternatively, it may be performed only when the vehicle is running at a low speed.

Further, in the above-described embodiment, the ABS control is selectively low-corrected when the mounting of the tempered tire is detected, while the select-low correction is performed when the vehicle is traveling on a low μ road and is running at an extremely low speed. The prohibition of the select row correction may be performed only when the tempered tire is mounted on the driven wheel of the vehicle. That is, if the wheel on which the tempered tire is mounted is the driving wheel of the vehicle, the rotational inertia of the driving wheel is large, so that it is unlikely that the ABS control is started in an extremely low-speed running state. There is no problem even if the correction is not prohibited.

[0077]

As described above, according to the first aspect of the present invention,
According to the braking apparatus A for an automobile according to the first aspect, when a wheel to which a spare tire is attached is detected, the anti-skid control can be corrected by the anti-skid control correcting means to suppress erroneous control. In addition, it is possible to reduce erroneous detection of the spare tire-mounted wheel by resetting the detection result of the spare tire-mounted wheel by determining that the rotation speed of each wheel is in the small deviation state by the rotation deviation state determining means. . In addition, by setting the determination time of the small deviation state to be longer when the spare tire is detected to be mounted on the driven wheel than when it is detected to be mounted on the driven wheel, the wheel of the driven wheel is set. Erroneous reset of the detection result due to spin or the like can be avoided. That is,
Increased the detection accuracy of the wheels mounted on spare tires as a whole,
It is possible to prevent a decrease in the braking performance and directional stability of the vehicle due to erroneous detection.

According to the second aspect of the present invention, the determination time for the small deviation state is set long only when the vehicle is traveling on a low μ road, so that the determination time is appropriately set according to the road surface condition. As a result, the determination accuracy can be improved.

According to the third aspect of the present invention, the determination time for the small deviation state is set long only when the vehicle is in a low-speed running state, so that the determination time is appropriately set according to the running state of the vehicle. , The determination accuracy can be improved.

According to the fourth aspect of the invention, when the vehicle is in a turning state, by setting the determination time longer than when the vehicle is not turning, the determination accuracy of the small deviation state can be further enhanced.

According to the fifth aspect of the invention, by setting the judgment time longer as the traveling speed of the vehicle is lower, the judgment accuracy of the small deviation state can be further improved.

Further, according to the braking apparatus A for an automobile according to the sixth aspect of the present invention, when a wheel on which a spare tire is mounted is detected, the anti-skid control correcting means performs select-low correction on the anti-skid control. While the directional stability of the vehicle at the time of braking can be ensured, when the vehicle is running at an extremely low speed, the select-low correction is suppressed, and a sense of discomfort that the braking force is released by the driver's braking operation is obtained. Can be reduced.

According to the eighth aspect of the present invention, the vehicle can be stopped promptly in response to the brake operation immediately before the stop, and the feeling of discomfort such as a loss of the braking force can be reduced.

According to the ninth aspect of the present invention, a low μ value at which the anti-skid control is started at the time of braking in an extremely low speed running state.
In the road, the effect of the invention of claim 6 can be sufficiently obtained.

According to the tenth aspect, when the spare tire is mounted on a driven wheel having a relatively small rotational inertia, there is a high possibility that the anti-skid control is started even in a very low-speed running state. Therefore, in such a case, the effect of the invention of claim 6 becomes particularly effective.

According to the eleventh aspect of the present invention, when anti-skid control is performed at the time of braking when the vehicle is running at a very low speed, select low correction is prohibited, and left and right independent anti-skid control is performed. By exerting the maximum braking force on each of the left and right wheels, the braking performance of the vehicle can be sufficiently enhanced and the feeling that the braking force comes off can be eliminated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first solving means of the present invention.

FIG. 2 is a configuration diagram of a second solving means of the present invention.

FIG. 3 is a diagram illustrating an overall configuration of a vehicle braking device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing the flow of basic control.

FIG. 5 is a flowchart showing a basic ABS control processing procedure.

FIG. 6 is a flowchart illustrating a processing procedure of EBD control.

FIG. 7 is an explanatory diagram showing a distribution state of a rear wheel side braking force to a front wheel side by EBD control in comparison with an ideal braking force distribution curve and the like.

FIG. 8 is a flowchart showing a processing procedure for detecting a mounted wheel of a tempered tire and ABS correction.

FIG. 9 is a flowchart illustrating a procedure for resetting the detection result of the mounted wheel of the tempered tire.

[Explanation of symbols]

A Brake device 6 Fluid pressure supply unit (braking means) 7FR, 7FL, 7RR, 7RL Brake device (braking means) 20a Anti-skid control means 20b Rear wheel braking control means 20c Spare tire mounted wheel detection means 20d Anti-skid control correction means 20e Select row correction suppression means, 20f rotation deviation state determination means 20g detection result reset means 20h determination time setting means 21 wheel speed sensor (rotation speed detection means)

Claims (11)

[Claims] 1. A braking means for applying a braking force to each wheel of a vehicle, a rotational speed detecting means for detecting a rotational speed of each of the wheels, and a braking speed based on a value detected by the rotational speed detecting means during braking of the vehicle. Anti-skid control means for controlling the operation of the braking means so that the slip state of each wheel converges to a predetermined target state by a braking force applied to each wheel; and A spare tire mounted wheel detecting means for detecting a wheel on which a spare tire smaller in diameter than the standard tire is mounted, and when the spare tire mounted wheel detecting means detects a mounted wheel of the spare tire, based on the detection result. An anti-skid control correcting means for correcting the control of the braking means by the anti-skid control means. A rotation deviation state determination unit that determines that the deviation amount of the rotational speed between the wheels is a small deviation state that is continuously equal to or less than a predetermined amount, which is equal to or longer than a set time, based on a value detected by the degree detection unit; When it is determined by the rotation deviation state determination unit that the vehicle is in the small deviation state, a detection result reset unit that resets a detection result obtained by the spare tire mounted wheel detection unit, and a determination time of the small deviation state by the rotation deviation state determination unit. A determination time setting means for setting the spare tire to be longer than a drive wheel when the wheel mounted on the spare tire is a driven wheel of the vehicle. 2. The determination time setting means according to claim 1, wherein the determination time setting means sets the determination time to be long only when the friction coefficient of the road surface on which the vehicle runs is a low μ road substantially equal to or less than a predetermined value. An automobile braking device, characterized in that: 3. The judgment time setting means according to claim 1, wherein the judgment time setting means sets the judgment time to be longer only when the vehicle is in a low-speed running state at a predetermined speed or less. An automobile braking device, characterized in that: 4. The vehicle according to claim 1, wherein the determination time setting means is configured to determine when the vehicle is in a turning state.
A braking device for a vehicle, wherein the determination time is set to be longer than when not. 5. The braking device for a vehicle according to claim 1, wherein the determination time setting means is configured to set the determination time longer as the traveling speed of the vehicle is lower. 6. A braking means for applying a braking force to each wheel of the vehicle, and the braking so that a slipping state of each wheel converges to a predetermined target state by the braking force applied to each wheel when the vehicle is braked. Anti-skid control means for controlling the operation of the means, from among the wheels, a spare tire mounted wheel detecting means for detecting a wheel on which a spare tire smaller in diameter than a standard tire is mounted, and the spare tire mounted wheel detecting means The anti-skid control means for correcting the control of the braking means by the anti-skid control means based on the detection result when the wheel mounted with the spare tire is detected by the anti-skid control. The correcting means applies a braking force that is substantially the same as the braking force applied to the mounted wheel of the spare tire to another wheel adjacent to the mounted wheel in the left-right direction. Select low correction for controlling the braking means by the anti-skid control means, and for suppressing the select low correction by the anti-skid control correction means when the vehicle is in a predetermined extremely low speed running state. A braking device for a vehicle, comprising a suppression unit. 7. The braking device for a vehicle according to claim 6, wherein the extremely low-speed traveling state is when the traveling speed of the vehicle is 10 km / h or less. 8. The braking apparatus for an automobile according to claim 6, wherein the extremely low-speed running state is a state immediately before the vehicle stops. 9. The select-low correction suppressing means according to claim 6, wherein the select-low correction suppressing means is provided only when the friction coefficient of the road surface on which the vehicle runs is a low μ road substantially equal to or less than a predetermined value.
A braking device for a vehicle, wherein the braking device is configured to suppress select-low correction by anti-skid control correcting means. 10. The select-row correction suppressing means according to claim 6, wherein the select-row correction suppressing means is configured to suppress the select-row correction by the anti-skid control correcting means only when the wheel on which the spare tire is mounted is a driven wheel of the vehicle. A braking device for an automobile, characterized in that: 11. The select-row correction suppressing means according to claim 6, wherein the select-row correction suppressing means inhibits the select-row correction by the anti-skid control correcting means. A braking device for an automobile, wherein the braking device is controlled independently by the anti-skid control device.