JP2007112391A - Stop holding device for vehicle and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stop holding device for a vehicle and a method therefor which can suppress generation of an unexpected movement of the vehicle when the vehicle is stopped on an inclined surface from the operation of an occupant. <P>SOLUTION: When an absolute value of the wheel speed VW of a front wheel is larger than a threshold value KVW in the case where a rear wheel having a braking force given from a parking brake by the operation of a parking lever keeping locked, a CPU executes the stop holding control processing. That is, the CPU imparts the braking force from the wheel cylinder to the front wheel by increasing the brake liquid pressure in the wheel cylinder for the front wheel. The CPU keeps the brake liquid pressure in the wheel cylinder for the front wheel, when it is determined that the wheel speed VW of the front wheel becomes "0 (zero)". <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle stop holding device for holding a stop state of a vehicle, and a vehicle stop holding method.

  Conventionally, for example, when a parking brake is operated or a transmission is operated so that a shift range becomes a parking range, a vehicle stop holding device that holds a stop state of the vehicle, and a vehicle stop holding method, For example, a vehicle stop and hold device and a vehicle stop and hold method described in Patent Document 1 have been proposed. That is, in the vehicle stop and hold device described in Patent Document 1, when the parking lever is operated (“ON” operation), braking force is applied to the rear wheel (first wheel) among the wheels of the vehicle. A parking brake (first braking means) is provided.

Here, when the vehicle is stopped on a road surface (slope) having an inclination based on the braking force from the parking brake, when the μ value of the road surface is relatively low, the vehicle is moved downward in the slope direction of the slope. Unexpected movement (i.e., vehicle downhill) may occur. In such a case, in the vehicle stop and hold device described in Patent Document 1, the braking force of the vehicle as a whole is obtained by applying to the rear wheels a braking force equal to or greater than the braking force corresponding to the amount of operation of the parking lever. It is supposed to increase. For this reason, even when the vehicle is stopped on a slope having a low μ value, the occurrence of the vehicle sliding down is suitably suppressed.
JP-A-8-482219 (Claim 1)

  By the way, in the vehicle stop holding device described in Patent Document 1, when the vehicle is stopped on the slope by operating the parking lever “ON”, when the vehicle slips down, the amount of operation of the parking lever or more is exceeded. The braking force is applied to the rear wheels. However, in the method of maintaining the stop of the vehicle by applying the braking force only to the rear wheels among the wheels, there is a limit to the increase of the braking force of the entire vehicle, and the stopped state of the vehicle can be reliably maintained (held). It was hard to say. That is, depending on the slope of the road surface, the μ value, etc., there is still a possibility that the vehicle may slide down to the lower side of the slope.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress the occurrence of unexpected movement of the vehicle when the vehicle is stopped on the slope based on the operation of the passenger. An object of the present invention is to provide a vehicle stop holding device and a vehicle stop holding method.

  In order to achieve the above object, the invention according to claim 1 relating to a vehicle stop holding device detects a wheel speed (VW) of each wheel (FR, FL, RR, RL) of the vehicle (C). Braking force (BP1) on the speed detection means (SE3, SE4, SE5, SE6) and the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL) When the braking force (BP1) is applied to the first wheels (RR, RL) by the first braking means (PKB) capable of applying the braking force, the first wheels (RR, RL) are in a locked state. In this case, the second wheel other than the first wheel (RR, RL) among the wheels (FR, FL, RR, RL) detected by the wheel speed detecting means (SE3, SE4, SE5, SE6). Wheel speed (VW) of wheels (FR, FL) The wheel speed determination means (60) for determining whether or not the pair value is larger than a preset threshold value (KVW), and when the determination result by the wheel speed determination means (60) is affirmative determination, Of the wheels (FR, FL, RR, RL) to at least the second wheel (FR, FL) so that the braking force (BP2) is also applied to the second wheel (FR, FL). The gist of the invention is that it includes control means (60) for controlling the second braking means (36a, 36b) capable of applying power (BP2).

  In the above configuration, when the first wheel to which the braking force is applied from the first braking means is in a locked state, if the absolute value of the wheel speed of the second wheel becomes larger than the threshold value, the second braking means A braking force is also applied to the second wheel. Therefore, as a result of the braking force being applied to all the wheels, the braking force of the entire vehicle increases as compared with the case where the braking force is applied only to the first wheel. Therefore, when the vehicle is stopped on the slope based on the operation of the passenger, it is possible to suppress the occurrence of unexpected movement of the vehicle.

  According to a second aspect of the present invention, in the vehicle stop and hold device according to the first aspect, the second braking means (36a, 36b) is configured such that the first braking means (PKB) is the first wheel (RR). , RL) is applied to at least the second wheel (FR, FL) of each wheel (FR, FL, RR, RL) with a braking force (BP2) having a braking method different from the braking force (BP1) applied to the wheel (FR, FL). To give.

  In the above configuration, a braking force having a braking method different from the braking force applied to the first wheel by the first braking means is applied to at least the second wheel among the wheels. Therefore, the braking force of the entire vehicle can be further increased by applying the braking force of the different braking system from the second braking means to the first wheel in addition to the second wheel. It becomes like this.

  According to a third aspect of the present invention, in the vehicle stop and hold device according to the first or second aspect, the control means (60) is affirmative in the determination result by the wheel speed determination means (60). In this case, the absolute value of the wheel speed (VW) of the second wheel (FR, FL) detected by the wheel speed detecting means (SE3, SE4, SE5, SE6) is less than the threshold value (KVW). The second aspect is to control the second braking means (36a, 36b).

  In the above configuration, braking force is applied to the second wheel from the second braking means so that the absolute value of the wheel speed is equal to or less than the threshold value. For this reason, the occurrence of unexpected movement of the vehicle is more effectively suppressed.

  According to a fourth aspect of the present invention, in the vehicle stop holding device according to the first or second aspect, a road surface inclination detecting means for detecting the inclination (gr) of the road surface on which the vehicle (C) has stopped. 60, SE8) and the braking force (BP2) for the second wheel (FR, FL) according to the road surface inclination (gr) detected by the road surface inclination detecting means (60, SE8). Braking force setting means (60), and the control means (60) is set by the braking force setting means (60) when the determination result by the wheel speed determination means (60) is affirmative. The gist is to control the second braking means (36a, 36b) so that the braking force (BP2) applied to the second wheels (FR, FL).

  In the above configuration, a braking force corresponding to the slope of the road surface is applied to the second wheel. In other words, it is possible to delay the progress of the deterioration of the second braking means by restricting the braking force being applied to the second wheel more than necessary.

  According to a fifth aspect of the present invention, in the vehicle stop and hold device according to the fourth aspect, the braking force (BP2) for the second wheels (FR, FL) is associated with the slope (gr) of the road surface. The braking force setting means (60) further includes a storage means (61) for storing in a state where the braking force is set, and the braking force setting means (60) corresponds to the road surface inclination (gr) detected by the road surface inclination detection means (60, SE8). The gist is to read the power (BP2) from the storage means (61).

  In the above configuration, the braking force applied to the second wheel is set by reading the braking force corresponding to the slope of the road surface from the storage means. That is, it is not necessary to perform arithmetic processing using the relational expression in order to set the braking force applied to the second wheel by the second braking means. Therefore, the processing load of the braking force setting means is reduced well.

  According to a sixth aspect of the present invention, in the vehicle stop holding device according to any one of the first to fifth aspects, the drive wheel (FR) of the wheels (FR, FL, RR, RL). , FL), an accelerator pedal operation determining means (60) for determining whether or not an accelerator pedal (17) operated to give a driving force is operated, and the first wheel (RR, RL) is further provided with braking force application determining means (60) for determining whether or not the braking force (BP1) from the first braking means (PKB) is applied, and the control means (60). Is determined when at least one of the determination result by the accelerator pedal operation determination means (60) and the determination result by the braking force application determination means (60) is switched from negative determination to positive determination. 2 wheels (FR, F Wherein to stop the application of the braking force (BP2) for the) second braking means (36a, 36b) is summarized in that to control the.

  In the above configuration, when at least one of the operation of the accelerator pedal and the stop of the application of the braking force from the first braking means to the first wheel is detected, the braking from the second braking means to the second wheel is detected. Stop applying power. Therefore, when the occupant subsequently operates the vehicle, the feeling of drag that the occupant feels based on the braking force from the second braking means on at least the second wheel of each wheel is reduced.

  The invention according to claim 7 is a wheel speed detecting means (SE3, SE4, SE5, SE6) for detecting a wheel speed (VW) of each wheel (FR, FL, RR, RL) of the vehicle (C); The first braking means (PKB) capable of applying a braking force (BP1) to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL). When the braking force (BP1) is applied to the wheels (RR, RL) of the first wheel (RR, RL), the wheel speed detection means (SE3, SE4, SE5, The absolute value of the wheel speed (VW) of the second wheel (FR, FL) other than the first wheel (RR, RL) among the wheels (FR, FL, RR, RL) detected by SE6). Is greater than a preset threshold (KVW) Wheel speed determining means (60) for determining the first wheel braking means and the first braking means for the second wheel (FR, FL) when the determination result by the wheel speed determining means (60) is affirmative. The first wheel (RR, RL) and the braking force (BP2) equivalent to the braking force (BP1) applied by (PKB) to the first wheel (RR, RL) The second braking means (70) configured to be able to switch between the second wheel (FR, FL) to a connected state or a non-connected state, the second braking means (70) being the first wheel. The gist of the invention is that it includes control means (60) for controlling to be in a switching mode in which a connection state is established between (RR, RL) and the second wheel (FR, FL).

  In the above configuration, when the first wheel to which the braking force is applied from the first braking means is in a locked state, if the absolute value of the wheel speed of the second wheel becomes larger than the threshold value, the second braking means As a result of being driven to connect the first wheel and the second wheel, the braking force applied to the first wheel is transmitted to the second wheel. That is, a braking force equivalent to the braking force applied to the first wheel by the first braking means is also applied to the second wheel. Therefore, the braking force is applied to all the wheels, and the braking force of the entire vehicle increases as compared with the case where the braking force is applied only to the first wheel. Therefore, when the vehicle is stopped on the slope based on the operation of the passenger, it is possible to suppress the occurrence of unexpected movement of the vehicle.

  On the other hand, the invention according to claim 8 according to the vehicle stop-holding method includes a first wheel (RR, RR) constituting a part of the wheels (FR, FL, RR, RL) of the vehicle (C). When the first wheel (RR, RL) is in a locked state due to the braking force (BP1) being applied to RL), the first of the wheels (FR, FL, RR, RL). It is determined whether the absolute value of the wheel speed (VW) of the second wheel (FR, FL) other than the other wheel (RR, RL) is larger than a preset threshold value (KVW), and the determination result is If the determination is affirmative, the gist is that the braking force (BP2) is also applied to the second wheels (FR, FL).

With the configuration described above, the same effects as those of the first aspect of the invention can be achieved.
According to a ninth aspect of the present invention, in the vehicle stop and hold method according to the eighth aspect, when the determination result is an affirmative determination, at least the first of the wheels (FR, FL, RR, RL). The gist is to apply a braking force (BP2) having a braking method different from the braking force (BP1) applied to the first wheel (RR, RL) to the second wheel (FR, FL). To do.

With the above configuration, the same operational effects as in the case of the invention described in claim 2 can be obtained.
In the invention according to claim 10, the braking force (BP1) is applied to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL) of the vehicle (C). When the first wheel (RR, RL) is in a locked state by being given, the wheel other than the first wheel (RR, RL) among the wheels (FR, FL, RR, RL). It is determined whether or not the absolute value of the wheel speed (VW) of the second wheel (FR, FL) is larger than a preset threshold value (KVW), and when the determination result is affirmative determination, By transmitting the braking force (BP1) applied to one wheel (RR, RL) to the second wheel (FR, FL), the braking force (BP2) equivalent to the braking force (BP1) is transmitted. ) For the second wheel (FR, FL) To.

  With the above configuration, the same function and effect as in the case of the seventh aspect of the invention can be achieved.

(First embodiment)
Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle). Unless otherwise specified, the left-right direction in the following description is the same as the left-right direction in the vehicle traveling direction.

  As shown in FIG. 1, the vehicle stop and hold device 11 in this embodiment includes a plurality of (four in this embodiment) wheels (right front wheel FR, left front wheel FL, right rear wheel RR, and left rear wheel RL). Of these, the front wheels FR and FL are mounted on a vehicle (so-called front wheel drive vehicle) that functions as drive wheels. The stop holding device 11 transmits a driving force generated by an engine 12 as a driving source to the front wheels FR and FL, and the front wheels FR and FL as steered wheels (also referred to as “steered wheels”). A front wheel turning mechanism 14 for turning and a braking force applying mechanism 15 for applying a braking force to each wheel FR, FL, RR, RL are provided. In addition, the stop holding device 11 is provided with a parking brake PKB that is separately configured with a braking method different from that of the braking force applying mechanism 15 and the mechanisms 13, 14, and 15 according to the traveling state of the vehicle. And an electronic control unit (also referred to as “ECU”) 16 for controlling. The engine 12 generates a driving force corresponding to the depression operation of the accelerator pedal 17 by a vehicle occupant.

  The driving force transmission mechanism 13 includes a throttle valve actuator (for example, a DC motor) 20 for controlling the opening degree of a throttle valve 19 that varies the opening cross-sectional area of the intake passage 18 a in the intake pipe 18, and an intake port of the engine 12. A fuel injection device 21 having an injector for injecting fuel is provided in the vicinity (not shown). The driving force transmission mechanism 13 is provided with a transmission 22 connected to the output shaft of the engine 12 and a differential gear 23 that appropriately distributes the driving force transmitted from the transmission 22 and transmits it to the front wheels FL and FR. It has been. Further, the driving force transmission mechanism 13 is provided with an accelerator opening sensor SE1 for detecting the depression amount (opening) of the accelerator pedal 17.

  The front wheel steering mechanism 14 is provided with a steering wheel 24, a steering shaft 25 to which the steering wheel 24 is fixed, and a steering actuator 26 connected to the steering shaft 25. The front wheel steering mechanism 14 includes a tie rod 27 that includes a tie rod that can be moved in the left-right direction of the vehicle by a steering actuator 26 and a link that steers the front wheels FL and FR by the movement of the tie rod. Is provided. Further, the front wheel steering mechanism 14 is provided with a steering angle sensor SE2 for detecting the steering angle of the steering wheel 24.

  The parking brake PKB is used when the vehicle is parked, and includes a parking lever 28 operated by a passenger. A ratchet mechanism (not shown) is provided in the parking lever 28, and wires WK are extended from the parking lever 28 toward the rear wheels (first wheels) RR and RL. When the parking lever 28 is operated, the braking force is applied to the rear wheels RR and RL by pulling the wires WK. Further, when the operation of the parking lever 28 is released, the pulled state of each wire WK is released so that the braking force is not applied from the parking brake PKB to the rear wheels RR and RL. It has become. Therefore, in the present embodiment, the parking brake PKB is a first braking means that can apply a braking force to the rear wheels (first wheels) RR, RL constituting a part of the wheels FR, FL, RR, RL. It is supposed to function as.

Next, the braking force application mechanism 15 will be described with reference to FIG.
As shown in FIG. 2, the braking force applying mechanism 15 of the present embodiment includes a hydraulic pressure generating device 32 having a master cylinder 30 and a booster 31, and a hydraulic pressure control device having two hydraulic pressure circuits 33 and 34 (FIG. 2). Is shown by a two-dot chain line). The hydraulic circuits 33 and 34 are connected to the hydraulic pressure generator 32 and are connected to wheel cylinders 36a, 36b, 36c, and 36d provided corresponding to the wheels FR, FL, RR, and RL. . That is, the wheel cylinder 36a corresponds to the right front wheel FR, and the wheel cylinder 36b corresponds to the left front wheel FL. Further, the wheel cylinder 36c corresponds to the right rear wheel RR, and the wheel cylinder 36d corresponds to the left rear wheel RL. Therefore, in the present embodiment, the wheel cylinders 36a and 36d are used for the front wheels (second wheels) FR and FL other than the rear wheels (first wheels) RR and RL among the wheels FR, FL, RR, and RL. Thus, it functions as a second braking means capable of applying a braking force.

  The hydraulic pressure generating device 32 is provided with a brake pedal 37, and the master cylinder 30 and the booster 31 of the hydraulic pressure generating device 32 are driven based on the brake pedal 37 being depressed by a vehicle occupant. It is like that. The master cylinder 30 is provided with two output ports 30a and 30b. The first hydraulic circuit 33 is connected to one of the output ports 30a and 30b, and the other of the output ports 30a and 30b. A second hydraulic circuit 34 is connected to the output port 30b. Further, the hydraulic pressure generating device 32 is provided with a brake switch SW1 that transmits a signal to the electronic control device 16 when the brake pedal 37 is operated.

  The hydraulic pressure control device 35 includes a pump 38 for increasing the brake hydraulic pressure in the first hydraulic pressure circuit 33, a pump 39 for increasing the brake hydraulic pressure in the second hydraulic pressure circuit 34, and each pump. A motor M for driving the motors 38 and 39 at the same time is provided. In addition, reservoirs 40 and 41 for storing brake oil are provided on the hydraulic circuits 33 and 34, and the brake oil in the reservoirs 40 and 41 is supplied to the hydraulic circuit based on driving of the pumps 38 and 39. 33 and 34 are supplied. Furthermore, hydraulic pressure sensors PS1 and PS2 for detecting the brake hydraulic pressure in the master cylinder 30 are provided in the hydraulic pressure circuits 33 and 34, respectively.

  The first hydraulic circuit 33 includes a right front wheel path 33a for the wheel cylinder 36a (for the right front wheel FR) connected to the wheel cylinder 36a corresponding to the right front wheel FR, and a wheel cylinder 36d corresponding to the left rear wheel RL. And a left rear wheel path 33b for the wheel cylinder 36d (for the left rear wheel RL) connected to the. On each of the paths 33a and 33b, normally open solenoid valves 42 and 43 and normally closed solenoid valves 44 and 45 are provided, respectively.

  Similarly, the second hydraulic circuit 34 corresponds to the left front wheel path 34a for the wheel cylinder 36b (for the left front wheel FL) connected to the wheel cylinder 36b corresponding to the left front wheel FL, and the right rear wheel RR. A right rear wheel path 34b for the wheel cylinder 36c (for the right rear wheel RR) connected to the wheel cylinder 36c is formed. On each of the paths 34a and 34b, normally open electromagnetic valves 46 and 47 and normally closed electromagnetic valves 48 and 49 are provided, respectively.

  In addition, a normally open proportional solenoid valve 50 is connected to the master cylinder 30 side of the first hydraulic circuit 33 with respect to the portions branched into the paths 33a and 33b, and in parallel with the proportional solenoid valve 50. A relief valve 51 is connected. The proportional solenoid valve 50 and the relief valve 51 constitute a proportional differential pressure valve 52. The proportional differential pressure valve 52 can generate a hydraulic pressure difference (brake hydraulic pressure difference) on the master cylinder 30 side and the wheel cylinders 36a and 36d side with respect to the proportional differential pressure valve 52 based on control by the electronic control unit 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 51 a constituting the relief valve 51. The first hydraulic circuit 33 is formed with a branch hydraulic pressure path 33c branched from between the reservoir 40 and the pump 38 toward the master cylinder 30. On the branch hydraulic pressure path 33c, a branch hydraulic pressure path 33c is formed. A normally closed electromagnetic valve 53 is connected.

  Similarly, a normally open proportional solenoid valve 54 is connected to the master cylinder 30 side of the second hydraulic circuit 34 that is branched to the paths 34 a and 34 b, and in parallel with the proportional solenoid valve 54. A relief valve 55 is connected. The proportional solenoid valve 54 and the relief valve 55 constitute a proportional differential pressure valve 56. The proportional differential pressure valve 56 can generate a hydraulic pressure difference (brake hydraulic pressure difference) between the master cylinder 30 side and the wheel cylinders 36b and 36c than the proportional differential pressure valve 56, based on control by the electronic control unit 16. Note that the maximum value of the hydraulic pressure difference is a value based on the urging force of the spring 55a constituting the relief valve 55. Further, the second hydraulic pressure circuit 34 is formed with a branch hydraulic pressure passage 34c branched from between the reservoir 41 and the pump 39 toward the master cylinder 30, and on the branch hydraulic pressure passage 34c. A normally closed electromagnetic valve 57 is connected.

  Here, changes in the brake fluid pressure in the wheel cylinders 36a to 36d when the solenoid coils of the solenoid valves 42 to 49 are in an energized state and in a non-energized state will be described. In the following description, it is assumed that the proportional solenoid valves 50 and 54 are in a closed state and the solenoid valves 53 and 57 on the branch hydraulic pressure paths 33c and 34c are in a closed state.

  First, when all the solenoid coils of the solenoid valves 42 to 49 are in a non-energized state, the normally open solenoid valves 42, 43, 46, 47 remain open and the normally closed solenoid valves 44, 45, 48 and 49 remain closed. Therefore, when the pumps 38 and 39 are driven, the brake oil in the reservoirs 40 and 41 flows into the wheel cylinders 36a to 36d via the paths 33a, 33b, 34a and 34b, and the wheels The brake fluid pressure in the cylinders 36a to 36d will increase.

  On the other hand, when all the solenoid coils of the solenoid valves 42 to 49 are energized, the normally open solenoid valves 42, 43, 46, 47 are closed and the normally closed solenoid valves 44, 45 are closed. , 48, 49 are opened. Therefore, brake oil flows from the wheel cylinders 36a to 36d to the reservoirs 40 and 41 via the paths 33a, 33b, 34a, and 34b, and the brake hydraulic pressure in the wheel cylinders 36a to 36d decreases. Become.

  When only the solenoid coils of the normally open solenoid valves 42, 43, 46, and 47 among the solenoid valves 42 to 49 are energized, all the solenoid valves 42 to 49 are closed. Therefore, the flow of brake oil through each path 33a, 33b, 34a, 34b is restricted. As a result, the brake hydraulic pressure in each wheel cylinder 36a-36d is maintained at its hydraulic pressure level.

  As shown in FIG. 1, the electronic control device 16 is mainly configured by a digital computer including a CPU 60, a ROM 61, and a RAM 62 as control means, and a drive circuit (not shown) for driving each device. ing. The ROM 61 has a control program for controlling the hydraulic pressure control device 35 (drive of the motor M, the electromagnetic valves 42 to 49, 53, 57 and the proportional electromagnetic valves 50, 54), and various constants (thresholds described later). Etc. are stored. Also, the RAM 62 is recorded with various information that can be appropriately rewritten while the vehicle stop holding device 11 is being driven.

  Further, the brake switch SW1, the hydraulic pressure sensors PS1 and PS2, the accelerator opening sensor SE1, and the steering angle sensor SE2 are connected to an input side interface (not shown) of the electronic control device 16, respectively. Further, the input side interface detects that the wheel speed sensors SE3, SE4, SE5, SE6 for detecting the wheel speeds of the wheels FR, FL, RR, RL and the parking lever 28 are operated. A parking brake operation detection sensor SE7 is connected to each other. Further, a vehicle body acceleration sensor (also referred to as “front-rear G sensor”) SE8 for detecting the vehicle body acceleration of the vehicle is connected to the input side interface. That is, the CPU 60 receives signals from the brake switch SW1, the hydraulic pressure sensors PS1 and PS2, and the various sensors SE1 to SE8.

  On the other hand, the output side interface (not shown) of the electronic control unit 16 is connected to a motor M for driving the pumps 38, 39, the solenoid valves 42 to 49, 53, 57, and the proportional solenoid valves 50, 54. ing. The CPU 60 individually operates the motor M, the solenoid valves 42 to 49, 53, 57 and the proportional solenoid valves 50, 54 based on the input signals from the switch SW1 and the sensors PS1, PS2, SE1 to SE8. It comes to control.

  Next, the control processing routine executed by the CPU 60 of the present embodiment will be described below based on the flowcharts shown in FIGS. FIG. 3 shows a stop holding control determination processing routine for setting whether or not to execute stop holding control, which will be described later, and FIG. 4 shows a stop holding control processing routine for executing stop holding control. Yes. FIG. 5 shows a stop holding control end determination processing routine.

First, the stop holding control determination processing routine shown in FIG. 3 will be described.
Now, the CPU 60 executes a stop holding control determination processing routine every predetermined cycle. In this stop and hold control determination processing routine, the CPU 60 determines whether or not the parking lever 28 is operated (“ON” operation) (step S10). That is, the CPU 60 determines whether braking force is applied to the rear wheels RR and RL by the parking brake PKB based on the signal received from the parking brake operation detection sensor SE7. If the determination result in step S10 is negative, the CPU 60 determines that the braking force is not applied from the parking brake PKB to the rear wheels RR and RL, and ends the stop holding control determination processing routine. .

  On the other hand, if the determination result of step S10 is affirmative, the CPU 60 determines that braking force is applied from the parking brake PKB to the rear wheels RR and RL, and receives from each wheel speed sensor SE3 to SE6. The wheel speed VW of each wheel FR, FL, RR, RL is detected based on the signal (step S11). In this regard, in the present embodiment, the CPU 60 and the wheel speed sensors SE3 to SE6 function as wheel speed detecting means. Subsequently, the CPU 60 determines whether or not the wheel speed VW of the rear wheels RR and RL detected in step S11 is “0 (zero)” (step S12). That is, the CPU 60 determines whether or not the rear wheels RR and RL are locked by applying a braking force to the rear wheels RR and RL from the parking brake PKB. If the determination result in step S12 is negative (wheel speed VW of the rear wheels RR and RL ≠ “0 (zero)”), the CPU 60 determines that the rear wheels RR and RL are not in the locked state, and stops. The holding control determination processing routine is terminated.

  On the other hand, if the determination result in step S12 is affirmative (the wheel speed VW of the rear wheels RR and RL = “0 (zero)”), the CPU 60 determines that the rear wheels RR and RL are locked, and the step It is determined whether or not the absolute value of the wheel speed VW of the front wheels (second wheels) FR and FL detected in S11 is greater than a preset threshold value (eg, “3”) KVW (step S13). In this regard, in this embodiment, the CPU 60 also functions as a wheel speed determination unit. The threshold value KVW is a value for determining whether or not to execute a stop holding control process, which will be described later, and is set in advance by an experiment or simulation.

  If the determination result in step S13 is negative (absolute value of wheel speed VW of front wheels FR, FL ≦ threshold value KVW), CPU 60 ends the stop holding control determination processing routine. On the other hand, if the determination result in step S13 is affirmative (absolute value of wheel speed VW of front wheels FR, FL> threshold value KVW), CPU 60 executes stop holding control processing (described in detail in FIG. 4) and A stop holding control processing flag (not shown) is set to “ON”. This stop holding control process flag is a flag for determining whether or not the stop holding control process is being executed. When the stop holding control process flag is being executed, the flag is set to “ON”. Set to “OFF”. Thereafter, the CPU 60 ends the stop holding control determination processing routine.

Next, the stop / hold control process routine (stop / hold control process) shown in FIG. 4 will be described.
In the stop holding control processing routine, the CPU 60 increases the brake fluid pressure BP in the wheel cylinders 36a, 36b for the front wheels FR, FL in order to increase the braking force on the front wheels FR, FL (step S20). . That is, the CPU 60 determines at least the front wheels FR of the wheels FR, FL, RR, RL so that the braking force is also applied to the front wheels FR, FL when both of the above-described steps S12, S13 are affirmative. , FL, the brake fluid pressure BP inside the wheel cylinders 36a, 36b capable of applying a braking force is controlled.

  Specifically, the CPU 60 includes only the electromagnetic valve 43 on the left rear wheel path 33b and the electromagnetic valve 47 on the right rear wheel path 34b among the electromagnetic valves 42 to 49 on the hydraulic circuits 33 and 34. The energized state is set, and the other solenoid valves 42, 44 to 46, 48, and 49 are deenergized. In addition, the CPU 60 drives the motor M and closes the proportional solenoid valves 50 and 54 by energizing the proportional solenoid valves 50 and 54.

  Subsequently, the CPU 60 detects the wheel speeds VW of the front wheels FR and FL based on the signals received from the wheel speed sensors SE3 and SE4 (step S21). Then, the CPU 60 determines whether or not the wheel speed VW of the front wheels FR and FL detected in step S21 is “0 (zero)” (step S22). That is, the CPU 60 determines whether or not the absolute value of the wheel speed VW of the front wheels FR and FL detected in step S21 has become “0 (zero)” which is a value equal to or less than the threshold value KVW. If the determination result of step S22 is negative (wheel speed VW of the front wheels FR and FL ≠ “0 (zero)”), the CPU 60 proceeds to steps S21 and S22 until the determination result of step S22 is affirmative. Repeatedly.

  On the other hand, if the determination result in step S22 is affirmative (the wheel speed VW of the front wheels FR and FL = “0 (zero)”), the CPU 60 determines the brake fluid pressure in the wheel cylinders 36a and 36b for the front wheels FR and FL. The pressure increase of BP is stopped, and the brake fluid pressure BP is maintained (step S23). Specifically, the CPU 60 stops the driving of the motor M and energizes the electromagnetic valve 42 on the right front wheel path 33a and the electromagnetic valve 46 on the left front wheel path 34a. Further, the CPU 60 deenergizes the solenoid valve 43 on the left rear wheel path 33b and the solenoid valve 47 on the right rear wheel path 34b, and deenergizes the proportional solenoid valves 50 and 54. The proportional solenoid valves 50 and 54 are opened.

Thereafter, the CPU 60 ends the stop holding control processing routine.
Next, the stop holding control end determination processing routine shown in FIG. 5 will be described.
Now, the CPU 60 executes a stop holding control determination processing routine every predetermined cycle. In this stop holding control determination process routine, the CPU 60 determines whether or not the stop holding control process is being executed (step S30). That is, the CPU 60 determines whether or not the stop holding control processing flag is set to “ON”. If the determination result in step S30 is negative (stop hold control process flag = “OFF”), the CPU 60 ends the stop hold control determination process routine.

  On the other hand, if the determination result in step S30 is affirmative (stop holding control processing flag = “ON”), the CPU 60 determines whether or not the parking lever 28 has been operated (“ON” operation). (Step S31). That is, the CPU 60 determines whether braking force is applied to the rear wheels RR and RL by the parking brake PKB based on the signal received from the parking brake operation detection sensor SE7. In this regard, in this embodiment, the CPU 60 also functions as a braking force application determination unit. If the determination result in step S31 is negative, the CPU 60 determines that the braking force has not already been applied from the parking brake PKB to the rear wheels RR and RL, and the process proceeds to step S33 described later. Transition.

  On the other hand, if the determination result in step S31 is affirmative, the CPU 60 determines that the braking force is still being applied from the parking brake PKB to the rear wheels RR and RL, and the accelerator pedal 17 is depressed. It is determined whether or not (step S32). That is, the CPU 60 determines whether or not the opening degree of the accelerator pedal 17 detected based on the signal from the accelerator opening degree sensor SE1 is not “0 (zero)”. In this regard, in this embodiment, the CPU 60 also functions as an accelerator pedal operation determination unit. If the determination result in step S32 is negative, the CPU 60 determines that the accelerator pedal 17 has not been depressed and ends the stop holding control determination processing routine. On the other hand, if the determination result of step S32 is affirmative, the CPU 60 determines that the accelerator pedal 17 has been depressed, and the process proceeds to step S33 described later.

  In step S33, the CPU 60 reduces the brake hydraulic pressure BP in the wheel cylinders 36a and 36b in order to stop applying the braking force to the front wheels FR and FL from the wheel cylinders 36a and 36b for the front wheels FR and FL. That is, when at least one of the stopping of the application of the braking force from the parking brake PKB to the rear wheels RR and RL and the depression of the accelerator pedal 17 is executed, the CPU 60 executes the front wheels FR, The application of braking force from the wheel cylinders 36a and 36b to the FL is stopped.

  Specifically, the CPU 60 reduces the brake fluid pressure BP in the wheel cylinders 36a and 36b by energizing the solenoid valve 44 on the right front wheel path 33a and the solenoid valve 48 on the left front wheel path 34a. Let When the CPU 60 determines that the brake fluid pressure BP in the wheel cylinders 36a and 36b has been sufficiently reduced, the electromagnetic valves 42 and 44 on the right front wheel path 33a and the electromagnetic valves 46 and 44 on the left front wheel path 34a. 48 is set to a non-energized state, and then the stop holding control determination processing routine is terminated.

Next, a vehicle stop holding method according to this embodiment will be described below with reference to FIGS.
Now, when the vehicle travels on a road surface (slope) having an inclination to the upper side of the slope, the passenger steps on the brake pedal 37 to stop the vehicle and operates the parking lever 28 to “ON”. As shown in FIG. 6, the braking force BP1 is applied to the rear wheels RR and RL of the vehicle C from the parking brake PKB. After that, when the depression operation of the brake pedal 37 is canceled, no braking force is applied to the front wheels FR and FL, and the vehicle C tries to move downwardly on the slope (so-called sliding down). The stopping state is maintained only by the braking force BP1 applied to the rear wheels RR and RL.

  By the way, when the μ value of the slope is relatively low, the force to move to the lower side of the slope of the vehicle C becomes larger than when the μ value is relatively high. When (the force to move below the slope of the vehicle C)> (the braking force BP1 from the parking brake PKB applied to the rear wheels RR, RL), the vehicle C moves down the slope. Unexpected movement occurs. That is, when the force to move to the lower side of the slope of the vehicle C is larger than the frictional force generated between the rear wheels RR and RL and the slope, the vehicle C tries to move to the lower side of the slope. .

  However, in this embodiment, when the rear wheels RR and RL are in the locked state by the braking force BP1 from the parking brake PKB, when the absolute value of the wheel speed VW of the front wheels FR and FL becomes larger than the threshold value KVW, The brake fluid pressure BP in the wheel cylinders 36a, 36b for the front wheels FR, FL is increased. That is, as shown in FIG. 7, a braking force BP2 corresponding to an increase in the brake fluid pressure BP in the wheel cylinders 36a and 36b is applied from the wheel cylinders 36a and 36b to the front wheels FR and FL. Therefore, the braking force BP1, BP2 is applied to the vehicle C with respect to all the wheels FR, FL, RR, RL. As a result, the braking force of the entire vehicle C is applied only to the rear wheels RR, RL. As compared with the case where a braking force is applied to Therefore, the stop state of the vehicle C is maintained well.

Therefore, in this embodiment, the following effects can be obtained.
(1) When the rear wheels (first wheels) RR and RL to which the braking force BP1 is applied from the parking brake (first braking means) PKB are locked, the front wheels (second wheels) FR and FL When the absolute value of the wheel speed VW is larger than the threshold value KVW, the braking force BP2 is applied to the front wheels FR, FL from the wheel cylinders (second braking means) 36a, 36b. Therefore, as a result of the braking force BP1, BP2 being applied to all the wheels FR, FL, RR, RL, as compared with the conventional case where the braking force BP1 is applied only to the rear wheels RR, RL. As a result, the amount of increase in the braking force of the entire vehicle C increases. Therefore, when the vehicle C stops on the slope based on the operation of the passenger, the unexpected movement of the vehicle C can be suppressed.

  (2) The front wheels (second wheels) FR and FL have wheel cylinders (second braking means) 36a for the front wheels FR and FL so that the absolute value of the wheel speed VW is "0 (zero)". A braking force BP1 is applied from 36b. Therefore, the occurrence of unexpected movement of the vehicle C can be suppressed better.

  (3) When at least one of the depression operation of the accelerator pedal 17 and the stop of the application of the braking force BP1 from the parking brake (first braking means) PKB to the rear wheels (first wheels) RR and RL is detected. Then, the application of the braking force BP2 from the wheel cylinders (second braking means) 36a, 36b to the front wheels (second wheels) FR, FL is stopped. Therefore, when the occupant subsequently operates the vehicle C, the sensation that the occupant feels based on the braking force BP2 from the wheel cylinders 36a, 36b on at least the front wheels FR, FL among the wheels FR, FL, RR, RL. Can be reduced.

(4) In the stop and hold control process, the braking force from the wheel cylinders 36c and 36d is not applied to the rear wheels RR and RL to which the braking force BP1 is applied by the parking brake PKB. Therefore, the progress of deterioration of the wheel cylinders 36c, 36d can be suppressed as compared with the case where braking force is applied from the wheel cylinders 36c, 36d to the rear wheels RR, RL in the stop holding control process.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different from the first embodiment in the content stored in the ROM and the processing content of the stop / hold control process (stop / hold control process routine). Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  The vehicle stop and hold device 11 in this embodiment includes an electronic control device 16. The electronic control device 16 is mainly configured by a digital computer including a CPU 60, a ROM 61, a RAM 62, and the like, and a drive circuit (not shown) for driving each device. The ROM 61 includes a control program for controlling the hydraulic pressure control device 35 (drive of the motor M, the electromagnetic valves 42 to 49, 53, 57 and the proportional electromagnetic valves 50, 54), and the wheel cylinder 36a for the front wheels FR, FL. , 36b (see FIG. 8) for setting the brake fluid pressure BP, a threshold value KVW, and the like are stored. The RAM 62 stores various information that can be appropriately rewritten while the vehicle stop holding device 11 is being driven.

Next, the map stored in the ROM 61 will be described with reference to FIG.
The map shown in FIG. 8 shows the relationship between the slope gr of the road surface on which the vehicle C stops and the brake fluid pressure BP in the wheel cylinders 36a and 36b for the front wheels FR and FL when the stop holding control process is executed. Is. The brake fluid pressure BP is set so as to increase as the road surface gradient gr increases. That is, the brake hydraulic pressure BP changes in proportion to the magnitude of the road surface gradient gr. For this reason, the braking force BP2 applied to the front wheels FR, FL increases as the slope gr of the road surface increases. Therefore, in the present embodiment, the ROM 61 functions as a storage unit that stores the braking force BP2 for the front wheels (second wheels) FR and FL in a state in which the braking force BP2 is associated with the road surface gradient gr.

Next, among the control processing routines executed by the CPU 60 of the present embodiment, the stop holding control processing routine will be described with reference to FIG.
In the stop holding control processing routine, the CPU 60 detects the road surface gradient gr based on the signal received from the vehicle body acceleration sensor SE8 (step S40). In this regard, in the present embodiment, the CPU 60 and the vehicle body acceleration sensor SE8 function as road surface inclination detection means. Subsequently, the CPU 60 sets the brake hydraulic pressure BP in the wheel cylinders 36a and 36b corresponding to the road surface gradient gr detected in step S40 based on the map shown in FIG. 3 (step S41). That is, the CPU 60 sets the braking force BP2 to be applied to the front wheels FR, FL from the wheel cylinders 36a, 36d for the front wheels FR, FL based on the detected road surface gradient gr. In this respect, in the present embodiment, the CPU 60 also functions as a braking force setting unit.

  Then, the CPU 60 increases the brake fluid pressure in the wheel cylinders 36a, 36d for the front wheels FR, FL to the brake fluid pressure BP set in step S42, and keeps the increased brake fluid pressure BP. (Step S42). Thereafter, the CPU 60 ends the stop holding control processing routine. Thus, when the brake fluid pressure BP in the wheel cylinders 36a and 36b is increased, the braking force BP2 is applied from the wheel cylinders 36a and 36b to the front wheels FR and FL. Therefore, the braking forces BP1 and BP2 are applied to all the wheels FR, FL, RR, and RL.

In this embodiment, in addition to the effects (1), (3), and (4) of the first embodiment, the following effects can also be obtained.
(5) A braking force BP2 corresponding to the slope gr of the road surface is applied to the front wheels (second wheels) FR, FL from the wheel cylinders (second braking means) 36a, 36b. That is, by restricting the braking force BP2 from being applied to the front wheels FR and FL more than necessary, the progress of deterioration of the wheel cylinders 36a and 36b can be delayed.

(6) By reading the brake fluid pressure BP (braking force BP2 from the second braking means) in the wheel cylinders 36a and 36b corresponding to the road surface gradient gr from the ROM (storage means) 61, the front wheels FR and FL are read. On the other hand, a braking force BP2 applied from the wheel cylinders 36a and 36b is set. That is, in order to set the braking force BP2 applied to the front wheels FR and FL by the wheel cylinders 36a and 36b, it is not necessary to perform arithmetic processing using a relational expression having the road surface gradient gr as a variable. Therefore, the processing load on the CPU (braking force setting means) 60 can be reduced well.
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, the vehicle on which the stop holding device is mounted is different from the first embodiment. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  As shown in FIGS. 10 and 11, the stop holding device 11 in this embodiment is a center differential that can transmit the driving force from the engine 12 to at least the rear wheels RR and RL among the wheels FR, FL, RR, and RL. It is mounted on a four-wheel drive vehicle C (so-called four-wheel drive vehicle) C having 70. The center differential 70 is connected to a differential gear 23 on the front wheels FR, FL side via a shaft 71 and is connected to a differential gear 23A on the rear wheels RR, RL side via a shaft 72.

  The center differential 70 is composed of a plurality (two in this embodiment) of gears 73 and 74. As shown in FIG. 11, when the gears 73 and 74 are meshed, The driving force from the engine 12 is transmitted to RR and RL. On the other hand, as shown in FIG. 10, when the gears 73 and 74 are separated, the driving force from the engine 12 is not transmitted to the rear wheels RR and RL. The center differential 70 functions as a differential device that absorbs this rotational speed difference when a difference occurs in the rotational speed between the front wheels FR, FL and the rear wheels RR, RL, for example, when the vehicle C is turning. It has become.

Next, a stop holding control process routine among the control process routines executed by the CPU 60 of the present embodiment will be described below.
When it is determined that the absolute value of the wheel speed VW of the front wheels FR and FL is larger than the threshold value KVW when the rear wheels RR and RL to which the braking force BP1 is applied from the parking brake PKB are in the locked state, the CPU 60 Executes stop holding control processing (stop holding control processing routine). In the stop holding control processing routine, the CPU 60 puts the gears 73 and 74 of the center differential 70 in mesh (see FIG. 11). That is, the rear wheels RR and RL and the front wheels FR and FL are switched from the non-connected state to the connected state.

  Then, the rear wheels RR and FL are placed on the rear wheels RR and FL by the parking brake PKB. A braking force BP1 applied to the RL is transmitted via the center differential 70. As a result, the rear wheel RR. Is also applied to the front wheels FR, FL by the parking brake PKB. A braking force BP2 equivalent to the braking force BP1 applied to the RL is applied. Therefore, the braking forces BP1, BP2 are applied to all the wheels FR, FL, RR, RL, and the braking force of the entire vehicle C is applied only to the rear wheels RR, RL. Larger than Thus, in this embodiment, the center differential 70 functions as a second braking means that can transmit the braking force BP1 applied to the rear wheels RR and RL to the front wheels FR and FL.

In the present embodiment, the following effects can be obtained.
(7) When the rear wheels (first wheels) RR and RL to which the braking force BP1 is applied from the parking brake (first braking means) PKB are locked, the front wheels (second wheels) FR and FL When the absolute value of the wheel speed VW becomes larger than the threshold value KVW, the CPU 60 drives and controls the center differential (second braking means) 70. That is, the gears 73 and 74 are brought into a meshing state so that the rear wheels RR and RL and the front wheels FR and FL are connected. As a result, the braking force BP1 from the parking brake PKB is also transmitted to the front wheels FR and FL, and the braking force BP2 equivalent to the braking force BP1 applied to the rear wheels RR and RL is also applied to the front wheels FR and FL. . Therefore, the braking forces BP1 and BP2 are applied to all the wheels FR, FL, RR, and RL, and compared with the conventional case where the braking force is applied only to the rear wheels RR and RL. The increase amount of the braking force of C as a whole increases. Therefore, when the vehicle C stops on the slope based on the operation of the passenger, the unexpected movement of the vehicle C can be suppressed.

  (8) In the present embodiment, unlike the first and second embodiments described above, the front wheels FR and FL are controlled using the center differential 70 without using the wheel cylinders 36a and 36b as the second braking means. Power BP2 is applied. Therefore, the progress of deterioration of the wheel cylinders 36a and 36b can be suppressed as compared with the case where the wheel cylinders 36a and 36b are used as the second braking means.

Each embodiment may be changed to another embodiment (another example) as follows.
In each embodiment, when the transmission 22 is an automatic transmission or a continuously variable transmission, when the shift range of the transmission 22 is a parking range, it is a driving wheel among the wheels FR, FL, RR, RL. A braking force may be applied to the front wheels FR and FL. At this time, the stop holding control process may be executed when the absolute value of the wheel speed VW of the rear wheels RR and RL becomes larger than the threshold value KVW. That is, by increasing the brake hydraulic pressure BP in the wheel cylinders 36c and 36d for the rear wheels RR and RL, a braking force is applied to the rear wheels RR and RL. In this case, the transmission 22 functions as the first braking means, and the wheel cylinders 36c and 36d for the rear wheels RR and RL function as the second braking means. In this case, the first wheel indicates the front wheels FR and FL, and the second wheel indicates the rear wheels RR and RL.

In each embodiment, an operation switch for stopping the stop holding control process may be provided separately from the accelerator pedal 17 and the parking lever 28.
In the second embodiment, the ROM 61 does not store the map shown in FIG. 8, but the relationship between the slope gr of the road surface and the brake fluid pressure BP in the wheel cylinders 36a and 36b for the front wheels FR and FL. The formula may be stored, and the brake fluid pressure BP may be set based on this relational formula.

  In the first embodiment, in the stop holding control process, the brake hydraulic pressure BP in the wheel cylinders 36a, 36b for the front wheels FR, FL is applied to the front wheels FR, FL by the braking force applying mechanism 15 with the largest braking force. May be set to the brake hydraulic pressure in the hydraulic circuits 33 and 34 (wheel cylinders 36a and 36b).

  In the first and second embodiments, in the stop holding control process, a braking force may be applied from the wheel cylinders 36a to 36d to all the wheels FR, FL, RR, FL. In this case, a braking force BP2 having a braking method different from the braking force BP1 applied by the parking brake PKB to the rear wheels RR and RL is applied to the front wheels FR and FL. Therefore, if the braking forces of different braking systems from the wheel cylinders 36a to 36d are applied to the rear wheels RR and RL in addition to the front wheels FR and FL, the braking force of the entire vehicle C is further increased. Will be able to.

In each embodiment, the brake pedal 37 may be a brake pedal that can be manually operated instead of a so-called foot pedal type brake pedal that is operated by a passenger's foot.
Similarly, the accelerator pedal 17 may be an accelerator pedal that can be manually operated instead of a so-called foot pedal-type accelerator pedal that is operated by a passenger's foot.

-In 1st and 2nd embodiment, you may materialize not the vehicle stop holding device 11 mounted in the front-wheel drive vehicle but the vehicle stop holding device mounted in a rear-wheel drive vehicle.
In each embodiment, the first hydraulic circuit 33 is connected to the wheel cylinder 36a for the right front wheel FR and the wheel cylinder 36b for the left front wheel FL, and the right rear wheel RR is connected to the second hydraulic circuit 34. The circuit configuration may be such that the wheel cylinder 36c for the left wheel and the wheel cylinder 36d for the left rear wheel RL are connected.

The block diagram of the stop holding | maintenance apparatus of the vehicle in 1st Embodiment. The block diagram of the braking force provision mechanism in 1st Embodiment. The flowchart which shows the stop holding | maintenance control determination processing routine in 1st Embodiment. The flowchart which shows the stop holding | maintenance control processing routine in 1st Embodiment. The flowchart which shows the stop holding | maintenance control completion | finish determination processing routine in 1st Embodiment. The schematic diagram which shows the state in which braking force was provided with respect to the rear wheel from the parking brake in 1st Embodiment. The schematic diagram which shows the state by which braking force was provided to all the wheels in 1st Embodiment. The map which shows the relationship between the inclination of a road surface, and the brake fluid pressure in the wheel cylinder for front wheels in 2nd Embodiment. The flowchart which shows the stop holding | maintenance control processing routine in 2nd Embodiment. The schematic diagram which shows the state in which braking force was provided with respect to the rear wheel from the parking brake in 3rd Embodiment. The schematic diagram which shows the state by which braking force was provided to all the wheels in 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Stop holding apparatus of a vehicle, 17 ... Accelerator pedal, 36a, 36b ... Wheel cylinder (2nd braking means), 60 ... CPU (wheel speed detection means, wheel speed determination means, control means, road surface inclination detection means, Braking force setting means, accelerator pedal operation determining means, braking force application determining means), 61... ROM (storage means), 70... Center differential (second braking means), BP1, BP2. , FL: front wheel (second wheel, drive wheel), gr: road surface inclination, KVW: threshold value, PKB ... parking brake, RR, RL ... rear wheel (first wheel), SE3 to SE6 ... wheel speed sensor (Wheel speed detection means), SE8: vehicle body acceleration sensor (road surface inclination detection means), VW: wheel speed.

Claims (10)

Wheel speed detection means (SE3, SE4, SE5, SE6) for detecting the wheel speed (VW) of each wheel (FR, FL, RR, RL) of the vehicle (C);
The first braking means (PKB) capable of applying a braking force (BP1) to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL). When the braking force (BP1) is applied to one wheel (RR, RL) and the first wheel (RR, RL) is in a locked state, the wheel speed detecting means (SE3, SE4, SE5) , SE6) of the wheels (FR, FL, RR, RL) detected by the absolute value of the wheel speed (VW) of the second wheel (FR, FL) other than the first wheel (RR, RL). Wheel speed determination means (60) for determining whether or not the value is larger than a preset threshold value (KVW);
When the determination result by the wheel speed determination means (60) is affirmative determination, each wheel (FR, FR, FL) is also applied to the second wheel (FR, FL). Control means (60) for controlling second braking means (36a, 36b) capable of applying braking force (BP2) to at least the second wheels (FR, FL) among FL, RR, RL). A vehicle stop holding device. The second braking means (36a, 36b) is a braking force (BP2) having a braking method different from the braking force (BP1) applied to the first wheels (RR, RL) by the first braking means (PKB). The vehicle stop holding device according to claim 1, wherein at least the second wheel (FR, FL) is provided to each of the wheels (FR, FL, RR, RL). The control means (60) is configured to detect the second wheel detected by the wheel speed detection means (SE3, SE4, SE5, SE6) when the determination result by the wheel speed determination means (60) is affirmative. The vehicle according to claim 1 or 2, wherein the second braking means (36a, 36b) is controlled so that an absolute value of a wheel speed (VW) of (FR, FL) is equal to or less than the threshold value (KVW). Stop holding device. Road surface inclination detecting means (60, SE8) for detecting the inclination (gr) of the road surface on which the vehicle (C) has stopped, and the road surface inclination detected by the road surface inclination detecting means (60, SE8) ( a braking force setting means (60) for setting a braking force (BP2) for the second wheel (FR, FL) according to gr),
The control means (60) determines that the braking force (BP2) set by the braking force setting means (60) is the second wheel when the determination result by the wheel speed determination means (60) is affirmative. The vehicle stop holding device according to claim 1 or 2, wherein the second braking means (36a, 36b) is controlled so as to be applied to (FR, FL). Storage means (61) for storing the braking force (BP2) for the second wheels (FR, FL) in a state associated with the slope (gr) of the road surface;
The braking force setting means (60) reads from the storage means (61) a braking force (BP2) corresponding to the road surface inclination (gr) detected by the road surface inclination detection means (60, SE8). Item 5. The vehicle stop holding device according to Item 4. An accelerator that determines whether or not an accelerator pedal (17) that is operated to apply a driving force to the driving wheels (FR, FL) among the wheels (FR, FL, RR, RL) has been operated. A pedal operation determining means (60) and a control for determining whether or not the braking force (BP1) from the first braking means (PKB) is applied to the first wheels (RR, RL). A power application determining means (60),
In the control means (60), at least one of the determination result by the accelerator pedal operation determination means (60) and the determination result by the braking force application determination means (60) is switched from negative determination to positive determination. Any one of claims 1 to 5 wherein the second braking means (36a, 36b) is controlled to stop applying the braking force (BP2) to the second wheels (FR, FL) when The vehicle stop-holding device according to claim 1. Wheel speed detection means (SE3, SE4, SE5, SE6) for detecting the wheel speed (VW) of each wheel (FR, FL, RR, RL) of the vehicle (C);
The first braking means (PKB) capable of applying a braking force (BP1) to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL). When the braking force (BP1) is applied to one wheel (RR, RL) and the first wheel (RR, RL) is in a locked state, the wheel speed detecting means (SE3, SE4, SE5) , SE6) of the wheels (FR, FL, RR, RL) detected by the absolute value of the wheel speed (VW) of the second wheel (FR, FL) other than the first wheel (RR, RL). Wheel speed determination means (60) for determining whether or not the value is larger than a preset threshold value (KVW);
When the determination result by the wheel speed determining means (60) is affirmative, the first braking means (PKB) is also connected to the first wheel (RR, FL) for the second wheel (FR, FL). RL) is applied to the first wheel (RR, RL) and the second wheel (FR, FL) so that a braking force (BP2) equivalent to the braking force (BP1) applied to RL) is applied. The second braking means (70) configured to be switchable between a connected state and a non-connected state, and the second braking means (70) is configured so that the first wheel (RR, RL) and the second wheel ( FR, FL) The vehicle stop holding apparatus provided with the control means (60) controlled so that it may become the switching aspect which makes a connection state between. As the braking force (BP1) is applied to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL) of the vehicle (C), the first When the other wheels (RR, RL) are in the locked state, the second wheels (FR, FL) other than the first wheels (RR, RL) among the wheels (FR, FL, RR, RL). It is determined whether or not the absolute value of the wheel speed (VW) of the vehicle is greater than a preset threshold value (KVW), and if the determination result is affirmative, the second wheel (FR, FL) A vehicle stop-holding method in which braking force (BP2) is also applied. When the determination result is affirmative, at least the second wheel (FR, FL) among the wheels (FR, FL, RR, RL) is the first wheel (RR, RL). The vehicle stop-holding method according to claim 8, wherein a braking force (BP2) having a braking method different from the braking force (BP1) applied to the vehicle is applied. As the braking force (BP1) is applied to the first wheels (RR, RL) constituting some of the wheels (FR, FL, RR, RL) of the vehicle (C), the first When the other wheels (RR, RL) are in the locked state, the second wheels (FR, FL) other than the first wheels (RR, RL) among the wheels (FR, FL, RR, RL). It is determined whether or not the absolute value of the wheel speed (VW) of the vehicle is greater than a preset threshold value (KVW). If the determination result is affirmative, the first wheel (RR, RL) By transmitting the braking force (BP1) applied to the second wheel (FR, FL), the braking force (BP2) equivalent to the braking force (BP1) is transmitted to the second wheel (FR). , FL), a vehicle stop-holding method.

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