JP5013118B2 - Left / right driving force control device - Google Patents

Description

  The present invention relates to a left / right driving force control device, and more particularly to a left / right driving force control technique for maintaining stable vehicle behavior.

2. Description of the Related Art A driving force distribution device has been developed that controls a yaw moment acting on a vehicle by generating a driving force difference between left and right wheels when the vehicle is turning, and improves the turning performance of the vehicle.
However, the conventional driving force distribution device causes a driving force difference between the left and right wheels, and has a problem that the slip of the left and right driving wheels cannot be suppressed when the vehicle goes straight.
Therefore, the present applicant has applied for a left / right driving force distribution device including a left / right driving force adjusting means and a differential limiting means (see Patent Document 1).
Japanese Patent Application No. 2007-145305

As in the above-mentioned Patent Document 1, in the left and right driving force distribution device in which the right and left driving force adjusting means is provided with the differential limiting means, it is necessary to control the right and left driving force adjusting means and the differential limiting means properly.
As a generally conceivable control method, there is a method in which the driving force adjustment amount by the left and right driving force adjustment means and the differential restriction amount by the differential restriction means are respectively calculated from the running state of the vehicle and each means is controlled separately Conceivable.

However, in such a method, there is a possibility that the right / left driving force adjusting means and the differential limiting means may be used at the same time. If the left and right driving force adjusting means and the differential limiting means are used at the same time, there is a problem that torque interference occurs due to an interlock, and the operating efficiency and controllability of the driving force distribution device are lowered.
In order to prevent such simultaneous use, a method of selectively switching only one of the left and right driving force adjusting means and the differential limiting means is conceivable. Due to the difference, there is a risk that a sudden change in the driving force difference occurs when the left / right driving force adjusting means and the differential limiting means are switched, and the vehicle behavior becomes discontinuous. Also, when traveling straight ahead, the left and right wheel speed difference frequently reverses left and right, and so-called hunting occurs between the left and right driving force adjusting means and the differential limiting means, which may result in discontinuous vehicle behavior. There is.

  The present invention has been made to solve such problems, and the object of the present invention is to adjust the left / right driving force adjusting means and differential limiting means while maintaining stable vehicle behavior according to the running state of the vehicle. It is an object of the present invention to provide a left and right driving force control device that can properly use the two.

  In order to achieve the above-described object, in the left / right driving force control device according to claim 1, a left / right driving force adjusting means capable of adjusting a driving force distribution between left and right wheels of a vehicle, and a differential restriction acting between the left and right wheels. Differential limiting means capable of limiting the differential between the left and right wheels by adjusting the force, wheel speed detecting means for detecting the wheel speed of each of the left and right wheels, and the left and right wheels according to the running state of the vehicle Control amount calculation means for calculating the left and right driving force control amount including the driving force movement direction between the left and right wheels detected by the left and right driving force control amount calculated by the control amount calculation means and the wheel speed detection means A driving force control selecting means for selecting one of the left and right driving force adjusting means and the differential limiting means based on a difference in speed; and the left and right driving force adjusting means selected by the driving force control selecting means or the difference Dynamic limiting means, Driving force control means for controlling based on the left and right driving force control amount calculated by the control amount calculating means, wherein the driving force control selecting means is a driving force of the left and right driving force control amount calculated by the control amount calculating means. When the moving direction and the wheel direction with the larger wheel speed among the left and right wheel speeds detected by the wheel speed detecting unit are the same, the left and right driving force adjusting unit is selected, and the driving force moving direction and the When the wheel direction in which the wheel speed is small is the same and the left / right driving force control amount is equal to or greater than a predetermined left / right driving force control amount, the differential limiting means is selected, and the driving force moving direction and the wheel speed are selected. When the direction of the small wheel is the same and the left / right driving force control amount is less than the predetermined left / right driving force control amount, the right / left driving force adjusting means or the differential limiting means selected immediately before is maintained. To do It is characterized in.

According to a second aspect of the present invention, in the left and right driving force control device according to the first aspect, the driving force control selecting means has the same driving force moving direction and the same wheel direction in which the wheel speed is small, and the right and left driving force control amount is predetermined. If the difference between the left and right wheel speeds is less than a predetermined wheel speed with less than the left and right driving force control amount, the right and left driving force adjusting means or the differential limiting means selected immediately before is maintained. It is said.
According to a third aspect of the present invention, in the left and right driving force control device according to the first or second aspect , the driving force control selecting means has the same driving force moving direction and a wheel direction in which the wheel speed is small, and a right and left driving force control amount. Is less than the predetermined control amount, the differential limiting means is selected when the direction of the difference between the left and right wheel speeds is reversed left and right at the same time as the driving force moving direction is reversed left and right.

In the left and right driving force control device according to claim 4 , in any one of claims 1 to 3, the driving force control selection means can control the predetermined left and right driving force control amount by the left and right driving force adjustment means. It is characterized by setting the force control amount limit.

According to the left and right driving force control apparatus according to claim 1 and 2 of the present invention using the above means, includes left and right driving force adjusting unit and the differential limiting unit, based on the left and right driving force control amount and the left and right wheel speed difference, right and left drive Driving force control is performed by selecting force adjusting means or differential limiting means. In the selection of the driving force control, when the driving force moving direction of the left and right driving force control amount is the same as the direction of the wheel with the higher wheel speed, that is, when turning is promoted, the left and right driving force adjusting means is selected to move the driving force. If the direction of the wheel is the same as the direction of the wheel with a small wheel speed, that is, when turning is suppressed, and if it is greater than or equal to a predetermined drive force control amount, the differential limiting means is selected and less than the predetermined drive force control amount. In some cases, the right / left driving force adjusting means or the differential limiting means selected immediately before is maintained.

In this way, by selecting the left / right driving force adjusting means or the differential limiting means based on one left / right driving force control amount and the left / right wheel speed difference, simultaneous use of the left / right driving force adjusting means and the differential limiting means is prevented. In addition, it is possible to suppress a sudden change in the driving force difference when the left and right driving force adjusting means and the differential limiting means are switched.
Further, when the driving force moving direction is the same as the wheel direction where the wheel speed is small and the left / right driving force control amount is less than the predetermined left / right driving force control amount , or the left / right driving force control amount is the predetermined left / right driving force. If the difference between the left and right wheel speeds is less than a predetermined wheel speed and less than the control amount, the right and left driving force control amount is maintained in order to maintain control of the right and left driving force adjusting means or differential limiting means selected immediately before. In addition, frequent switching of the left / right driving force adjusting means and the differential limiting means due to a change in the left / right wheel speed difference can be reduced.

Furthermore, by using differential limiting means that consumes less energy instead of the left and right driving force adjusting means when turning is suppressed, energy consumption can be suppressed, and thus fuel efficiency can be improved.
From these facts, since hunting between the right and left driving force adjusting means and the differential limiting means can be reduced and a sudden change in the driving force difference at the time of switching can be suppressed, discontinuity in vehicle behavior can be suppressed.

As a result, it is possible to properly use the left / right driving force adjusting means and the differential limiting means while maintaining a stable vehicle behavior according to the traveling state of the vehicle.
According to the left and right driving force control device of the third aspect , the driving force is moved from the state in which the driving force moving direction is the same as the wheel direction in which the wheel speed is small and the left and right driving force control amount is less than the predetermined left and right driving force control amount. When the force moving direction and the direction of the difference between the left and right wheel speeds are reversed at the same time, the differential limiting means is selected.

That is, when the left / right driving force control amount is in a substantially straight traveling state where the left / right driving force control amount is less than the predetermined left / right driving force control amount, When the difference is reversed, the differential limiting means is selected.
As described above, when the vehicle travels straight, the driving force adjustment control that distributes the driving force to either one of the left and right wheels is not performed, and by selecting the differential restriction control, the straight traveling stability can be improved.

According to the left and right driving force control device of the fourth aspect , since the limit of the controllable left and right driving force control amount is generally larger in the differential limiting means than in the left and right driving force adjusting means, the driving force control selecting means A predetermined left / right driving force control amount is set as a control limit in the left / right driving force adjusting means, and differential limit control is performed with a left / right driving force control amount larger than this.
Thereby, in the driving force control in the turning suppression direction, the left / right driving force control can be executed in a wider area than the control of only the left / right driving force adjusting means.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIGS. 1 to 4, FIG. 1 is a schematic configuration diagram of a left and right driving force control device according to the present invention, FIG. 2 is an enlarged view of a main part showing a left and right driving force distribution device, and FIG. FIG. 4 is a block diagram showing an output relationship, and FIG. 4 shows a control map showing a driving force control selection based on a driving force moving direction and a wheel speed difference.

A vehicle 1 shown in FIG. 1 has an engine 2 mounted on the front portion of the vehicle body, and has left front wheels 4L, right front wheels 4R (also referred to as front wheels 4), left rear wheels 6L, and right rear wheels 6R (also combined as drive wheels). It is a four-wheel drive vehicle equipped with a rear wheel 6).
Specifically, the vehicle 1 is driven on the front wheel 4 side and the rear wheel 6 side connected to the transmission 8, the transmission 8 connected to one side of the engine 2 as a drive source mounted on the front part of the vehicle body, and the transmission 8. The center differential 10 that distributes the force, the driving force distributed to the front wheel 4 side by the center differential 10 is distributed by the front differential 14 and the center differential 10 that distributes to the front wheel rotation shafts 12L and 12R of the left front wheel 4L and the right front wheel 4R, respectively. The propeller shaft 16 for transmitting the driving force to the rear wheel 6 side, and the traveling state of the vehicle 1 on the rear wheel rotation shafts 18L and 18R of the left rear wheel 6L and the right rear wheel 6R connected to one end of the propeller shaft 16 The left and right driving force distribution device 20 distributes the driving force according to the above.

The engine 2, the transmission 8, the center differential 10, and the front differential 14 are known, and the left / right driving force distribution device 20 will be described in detail below.
As shown in FIG. 2, the left / right driving force distribution device 20 includes a main body case 22, an input portion 24 that forms one end of the propeller shaft 16, a left rear wheel rotation shaft 18 </ b> L connected to the input portion 24, and a right The differential mechanism portion 26 disposed on the rear wheel rotation shaft 18R, the left / right driving force adjustment mechanism portion 28 (left / right driving force adjustment means) disposed on the right rear wheel rotation shaft 18R, and the left rear wheel rotation shaft A differential limiting mechanism 30 (differential limiting means) disposed on 18L is accommodated.

  The left and right driving force distribution device 20 allows the driving force input from the propeller shaft 16 to the left and right rear wheel rotation shafts 18L and 18R while allowing a difference in rotation between the left and right rear wheels 6L and 6R in the differential mechanism portion 26. The driving force can be transmitted, and the driving force of the left and right rear wheels 6L, 6R is distributed by moving one driving force of the left and right rear wheels 6L, 6R to the other driving force by the left / right driving force adjusting mechanism 28. It has a function. The left and right driving force adjusting mechanism 28 engages with the speed increasing / decreasing mechanism 32 that increases and decreases the speed of one of the left and right rear wheels 6L and 6R with respect to the other wheel. A right clutch 34 that moves the driving force to the right rear wheel 6R and a left clutch 36 that moves the driving force from the right rear wheel 6R to the left rear wheel 6L when engaged are configured.

  The differential limiting mechanism 30 of the left / right driving force distribution device 20 is provided with a so-called differential limiting clutch 38 formed of a multi-plate friction clutch. The differential limiting mechanism 30 has a function of limiting the differential between the left and right rear wheels 6L and 6R by engaging the differential limiting clutch 38. That is, when a wheel speed difference is generated between the left and right rear wheels 6L and 6R, if the differential limiting clutch 38 is engaged, the driving force moves from the higher wheel speed to the lower wheel speed. It becomes.

The differential limiting clutch 38 of the differential limiting mechanism 30 and the right clutch 34 and the left clutch 36 of the left / right driving force adjusting mechanism 28 are operated by hydraulic pressure from a hydraulic unit 40 mounted on the vehicle 1. .
Each wheel 4L, 4R, 6L, 6R of the vehicle 1 is provided with wheel speed sensors 42L, 42R, 44L, 44R (wheel speed detecting means) for detecting each wheel speed.

Further, the vehicle 1 includes a yaw rate sensor 46 that detects the yaw rate of the vehicle 1, a steering angle sensor 48 that detects the steering angle, a vehicle body speed sensor 50 that detects the vehicle body speed, an accelerator opening sensor 52 that detects the accelerator opening, and the like. Various sensors are provided.
These various sensors are electrically connected to an ECU (electronic control unit) 60 (driving force control means) mounted on the vehicle 1.

The ECU 60 controls various devices based on sensor information detected by various sensors.
For example, the ECU 60 has a function of controlling the left / right driving force adjusting mechanism unit 28 and the differential limiting mechanism unit 30 in the left / right driving force distribution device 20 via the hydraulic unit 40.
Specifically, in this ECU 60, as shown in FIG. 3, a first control amount calculation unit 62, a second control amount calculation unit 64, a third control amount calculation unit 66, a combined control amount calculation unit 68 (control amount calculation) Means), a driving force control selection unit 70 (driving force control selection means) is formed.

  The first control amount calculation unit 62 includes a yaw rate control amount calculation unit 72 that calculates a yaw rate control amount according to the difference between the target yaw rate and the actual yaw rate from the detection result from the yaw rate sensor 46, a steering angle sensor 48, and a vehicle body speed sensor. 50, a turning state control amount calculation unit 74 for calculating a turning state control amount according to the steering angle and the vehicle body speed from the detection result from 50, and slip control according to the wheel slip rate from the detection results of the rear wheel speed sensors 44L, 44R. A slip control amount calculation unit 76 for calculating the amount is provided.

  The first control amount calculation unit 62 calculates a first control amount by adding the control amounts calculated by the yaw rate control amount calculation unit 72, the turning state control amount calculation unit 74, and the slip control amount calculation unit 76. It has a function to do. The first control amount is a control amount for controlling the left / right driving force adjusting mechanism 28, that is, an engagement control amount of the right clutch 34 or the left clutch 36. Therefore, the left and right driving force movement direction in the rear wheel 6 is included. For example, the driving force movement to the right rear wheel 6R by the engagement of the right clutch 34 is positive, and the left clutch 36 is engaged to the left rear wheel 6L by the engagement of the left clutch 36. It is assumed that the driving force movement is indicated by a negative value.

  The second control amount calculation unit 64 includes a traction control amount calculation unit 78 that calculates a traction control amount corresponding to the accelerator opening from the detection result of the accelerator opening sensor 52. The second control amount calculation unit 64 has a function of calculating a second control amount for controlling the differential limiting mechanism unit 30 based on the traction control amount. The second control amount is an engagement control amount of the differential limiting clutch 38.

  Further, the third control amount calculation unit 66 determines a wheel speed difference that determines which of the left and right wheels is higher in the rear wheel 6 from the difference between the left and right wheel speeds obtained from the detection results of the rear wheel speed sensors 44L and 44R. A determination unit 80 is provided. The wheel speed difference determination unit 80 outputs an output value of -1 if the value obtained by subtracting the wheel speed of the left rear wheel 6L from the wheel speed of the right rear wheel 6R is positive, and outputs an output value of 1 if negative. is there. That is, the output value is -1 when the wheel speed of the right rear wheel 6R is larger, and the output value is 1 when the wheel speed of the left rear wheel 6L is larger.

  The third control amount calculation unit 66 multiplies the second control amount calculated by the second control amount calculation unit 64 by the output value from the wheel speed difference determination unit 80 to obtain the third control amount. It has a function to calculate. That is, the third control amount is a control amount that includes the driving force movement direction that suppresses the differential in the second control amount. Therefore, this third control amount is multiplied by the output value from the wheel speed difference determination unit 80, so that the driving force movement to the right rear wheel 6R is similar to the driving force movement direction in the first control amount calculation unit 62. Is positive, and the driving force movement to the left rear wheel 6L is indicated by a negative value.

Further, the composite control amount calculation unit 68 adds the first control amount calculated by the first control amount calculation unit 62 and the third control amount calculated by the third control amount calculation unit 66, and adds the composite control amount (left and right). The driving force control amount is calculated. Since the first control amount and the third control amount are control amounts each including the driving force movement direction, this combined control amount is also a control amount including the driving force movement direction.
Further, the driving force control selection unit 70 is based on the relationship between the driving force movement direction of the combined control amount calculated by the combined control amount calculating unit 68 and the left and right wheel speed difference obtained from the detection results of the rear wheel speed sensors 44L and 44R. In addition, it has a function of selecting whether to perform left / right driving force adjustment control by the left / right driving force adjustment mechanism 28 or differential restriction control by the differential restriction mechanism 30.

  For example, in the driving force control selection unit 70, as shown in FIG. 4, the composite control amount T with the driving force movement to the right rear wheel 6R being positive and the driving force movement to the left rear wheel 6L being negative is the vertical axis. The control for driving force control selection with the horizontal axis as the left-right wheel speed difference V is positive when the wheel speed of the right rear wheel 6R is high and negative when the wheel speed of the left rear wheel 6R is high. Based on the map, left / right driving force adjustment control or differential limit control is selected.

In the control map shown in FIG. 4, when the driving force moving direction of the combined control amount T and the wheel direction with the higher wheel speed are the same, that is, when the driving state is in the first quadrant and the third quadrant, the left / right driving is performed. The left / right driving force adjustment control by the force adjusting mechanism 28 is set to be selected.
That is, in the traveling state of the first quadrant and the third quadrant, the left and right driving force adjustment is performed so that the driving force is moved to the outer wheel side with respect to the turning direction of the vehicle 1 and the driving force is applied to the turning promotion direction, that is, the oversteer side. Control is selected. In the first quadrant, the right clutch 34 of the left and right driving force adjusting mechanism 28 is engaged, and in the third quadrant, the left clutch 36 is engaged according to the combined control amount.

  On the other hand, in the control map shown in FIG. 4, when the direction of the driving force movement direction of the combined control amount T is the same as the direction of the wheel side where the wheel speed is low, that is, the traveling state is in the second quadrant and the fourth quadrant. In this case, predetermined control amounts Ta and -Ta (hereinafter also referred to as a predetermined control amount | Ta |) and predetermined wheel speed differences Va and -Va (hereinafter also referred to as a predetermined wheel speed difference | Va |) are used. It is set to perform different control at the boundary. In general, the differential limiting mechanism 30 has a larger limit of the controllable composite control amount T and the left and right wheel speed difference V compared to the left and right driving force adjusting mechanism 28, and the predetermined control amount | Ta | The speed difference | Va | is set to the combined control amount T and the wheel speed difference V corresponding to the controllable limit of the left / right driving force adjusting mechanism 28.

  Specifically, in the second quadrant and the fourth quadrant, when the combined control amount | T | is a predetermined control amount | Ta | or more, or the left and right wheel speed difference | V | is a predetermined wheel speed difference | Va | That is, when V <−Va or Va <V, or T <−Ta or Ta <T, the differential limiting control by the differential limiting mechanism 30 is selected. That is, in such a traveling state, the differential limiting control is selected so that the driving force is moved toward the inner wheel with respect to the turning direction of the vehicle 1 and the driving force is applied to the turning suppression direction, that is, the understeer side. The In this case, the differential limiting clutch 38 of the differential limiting mechanism 30 is engaged according to the combined control amount.

In the second quadrant and the fourth quadrant, the combined control amount | T | is less than the predetermined control amount | Ta |, and the left and right wheel speed difference | V | is less than the predetermined wheel speed difference | Va |. That is, in the areas A and B where -Ta <T <T and -Va <V <Va, the driving force control executed immediately before is set to be maintained.
However, when the traveling state changes between the region A and the region B, the differential restriction control is set to be selected. That is, when the driving force moving direction is reversed left and right in the combined control amount T between the second quadrant and the fourth quadrant, the left and right wheel speed difference V is also reversed left and right. It is assumed that the differential limiting means is selected even when the operation is performed.

The operation of the left / right driving force control apparatus according to the present invention configured as described above will be described below.
Referring to FIG. 5, a left / right driving force control routine executed in the left / right driving force control apparatus according to the present invention is shown in a flowchart, and will be described below based on the flowchart.
First, in step S1, the ECU 60 reads the detection results of various sensors such as the yaw rate sensor 46, the steering angle sensor 48, the vehicle body speed sensor 50, the wheel speed sensors 42L, 42R, 44L, 44R, the accelerator opening sensor 52, and the like. .

In the subsequent step S2, the composite control amount calculation unit 68 adds the first control amount calculated by the first control amount calculation unit 62 and the third control amount calculated by the third control amount calculation unit 66, thereby combining control. The amount T is calculated.
In step S3, it is determined whether or not the driving force moving direction included in the composite control amount T calculated in step S2 is the same as the wheel direction in which the rear wheel 6 has a high wheel speed. That is, it is determined whether or not the traveling state at this time corresponds to the first quadrant or the third quadrant in the control map of FIG.

If the determination result is true (Yes), the process proceeds to step S4.
In step S4, the left / right driving force adjustment control is executed according to the composite control amount T calculated in step S2, and the routine returns. That is, in step S4, if the composite control amount T is positive, the right clutch 34 of the left and right driving force adjusting mechanism 28 is engaged, and if it is negative, the left clutch 36 is controlled.

On the other hand, when the determination result of the above step S3 is false (No), that is, the driving force moving direction of the combined control amount T is the same as the wheel direction in which the wheel speed is small, the second quadrant or second in the control map of FIG. If the four-quadrant traveling state is applicable, the process proceeds to step S5.
In step S5, it is determined whether the combined control amount | T | is greater than or equal to the predetermined control amount | Ta |, or whether the left and right wheel speed difference | V | is greater than or equal to the predetermined wheel speed difference | Va |, that is, T <−Ta or Ta <. It is determined whether T, V <−Va, or Va <V is satisfied.

If the determination result is true (Yes), the process proceeds to step S6.
In step S6, the engagement of the differential limiting clutch 38 of the differential limiting mechanism 30 is controlled according to the combined control amount calculated in step S2, and the routine returns.
On the other hand, if the determination result in step S5 is false (No), that is, if the vehicle is in the traveling state of region A or region B in the control map of FIG. 4, the process proceeds to step S7.

In step S7, it is determined whether or not the change is between region A and region B in the control map of FIG.
If the determination result is true (Yes), the process proceeds to step S6. That is, for example, the wheel speed difference V is negative, that is, the left wheel speed is larger and the wheel speed difference is positive, that is, the right wheel speed is larger from the traveling state (region A) where the combined control amount T is positive. When the travel state changes to the travel state (region B) in which the control amount T is negative, or vice versa, the process proceeds to step S6 and the differential limiting control is executed. To do.

On the other hand, when the determination result of step S7 is false (No), that is, when the travel state is in the region A or the region B instead of the change between the region A and the region B, the process proceeds to the step S8.
In step S8, the previous driving force control, that is, the driving force control selected one cycle before the control routine is maintained, and the routine returns. That is, if the driving state changes from the first quadrant and the third quadrant to the traveling state of the region A or the region B, the left / right driving force adjustment control is maintained, and the combined control amount | T | of the second quadrant and the fourth quadrant is predetermined. When the control amount | Ta | or more or the wheel speed difference | V | changes from the region of the predetermined wheel speed difference | Va | or more to the region A or the region B, the differential limiting control is maintained.

  As described above, in the left / right driving force control device according to the present invention, the left / right driving force distribution device 20 includes the left / right driving force adjustment mechanism 28 and the differential limiting mechanism 30, and the left / right driving force adjustment mechanism 28. And the combined control amount T corresponding to the differential limiting mechanism unit 30 is calculated, and either one of the selected left and right driving force adjusting mechanism unit 28 and the differential limiting mechanism unit 30 is set in accordance with the single combined control amount T. Control.

Therefore, simultaneous use of the left / right driving force adjusting mechanism 28 and the differential limiting mechanism 30 can be prevented, and a sudden change in the driving force difference when the left / right driving force adjusting control and the differential limiting control are switched is suppressed. be able to.
Further, the selection of the left / right driving force adjustment control and the differential restriction control is performed based on the combined control amount T and the left / right wheel speed difference V as shown in the control map of FIG.

Since the immediately preceding driving force control is maintained in the areas A and B in the control map of FIG. 4, frequent switching of the left and right driving force adjusting means and the differential limiting means due to changes in the combined control amount T and the left and right wheel speed difference V is maintained. Can be reduced.
Further, when the change is between the region A and the region B, the differential restriction control is selected, so that the driving force is distributed to either one of the left and right wheels when maintaining the straight traveling. The driving force adjustment control is not performed, and the differential limit control is surely selected, so that the straight running stability can be improved.

Further, in the second and fourth quadrants and in the traveling state outside the areas A and B, the driving force control is executed in a wider area only by the left and right driving force adjusting mechanism section 28 by selecting the differential limiting mechanism section 30. can do.
In addition, by using the differential limiting mechanism 30 that consumes less energy instead of the left / right driving force adjusting mechanism 28 when turning is suppressed, energy consumption can be suppressed, and thus fuel efficiency can be improved.

As a result, hunting between the left / right driving force adjustment control and differential limit control can be reduced, and sudden changes in the driving force difference at the time of switching of driving force control can be suppressed, thereby suppressing discontinuity in vehicle behavior. can do.
In this way, the left / right driving force control device according to the present invention can properly use the left / right driving force adjusting means and the differential limiting means while maintaining stable vehicle behavior in accordance with the running state of the vehicle.

Although the description about the embodiment of the left and right driving force control device according to the present invention is finished as above, the embodiment is not limited to the above embodiment.
In the above embodiment, the control map shown in FIG. 4 is used for driving force control selection, but the control map is not limited to that shown in FIG.
For example, as shown in FIG. 6 as a modification of the control map of FIG. 4, the setting of the predetermined wheel speed difference | Va | is eliminated, and the regions A and B may be set only with the predetermined limit amount | Ta | Absent.

Moreover, in the said embodiment, although the vehicle 1 is a four-wheel drive vehicle, it is applicable also to a two-wheel drive vehicle.
In the above embodiment, the left and right driving force distribution device 20 is provided with the left and right driving force adjusting mechanism portion 28 on the right side and the differential limiting mechanism portion 30 on the left side with respect to the differential mechanism portion 26. The left and right driving force distribution device is not limited to such a configuration. The left / right driving force control apparatus according to the present invention may be configured to include a left / right driving force adjusting means and a differential limiting means.

  Further, in the above embodiment, the combined control amount is calculated from the detection results of the yaw rate sensor 46, the steering angle sensor 48, the vehicle body speed sensor 50, the wheel speed sensors 42L, 42R, 44L, 44R, and the accelerator opening sensor 52. However, the composite control amount may be a control amount corresponding to the left / right driving force adjusting mechanism unit 28 and the differential limiting mechanism unit 30 and is not limited to the configuration of the embodiment.

  Moreover, in the said embodiment, it is not restricted to what adds a 3rd control amount and a 1st control amount as it is, and calculates a synthetic | combination control amount, For example, weighting of a 3rd control amount and a 1st control amount In order to change the value, a composite control amount may be calculated by adding a coefficient to one or both of them and adding them together.

It is a schematic block diagram of the right-and-left driving force control device concerning the present invention. It is a principal part enlarged view which shows a driving force distribution apparatus. It is a block diagram which shows the input / output relationship of ECU. It is a map which shows the driving force control selection based on a driving force moving direction and a wheel speed difference. It is a flowchart which shows the left-right driving force control routine performed in the left-right driving force control apparatus which concerns on this invention. It is a map which shows the driving force control selection based on the driving force moving direction and wheel speed difference in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 6 Rear wheel 20 Left-right drive force distribution apparatus 28 Left-right drive force adjustment mechanism part (left-right drive force adjustment means)
30 differential limiting mechanism (differential limiting means)
34 Right clutch 36 Left clutch 38 Differential limiting clutch 40 Hydraulic unit 42L, 42R, 44L, 44R Wheel speed sensor (wheel speed detection means)
46 Yaw rate sensor 48 Steering angle sensor 50 Vehicle speed sensor 52 Accelerator opening sensor 60 ECU (driving force control means)
68 Synthesis control amount calculation unit (control amount calculation means)
70 Driving force control selection unit (driving force control selection means)

Claims (4)

Left and right driving force adjusting means capable of adjusting the driving force distribution between the left and right wheels of the vehicle;
Differential limiting means capable of limiting the differential between the left and right wheels by adjusting the differential limiting force acting between the left and right wheels;
Wheel speed detecting means for detecting the wheel speed of each of the left and right wheels;
A control amount calculating means for calculating a left and right driving force control amount including a driving force moving direction between the left and right wheels according to a traveling state of the vehicle;
Based on the left / right driving force control amount calculated by the control amount calculating means and the difference between the left and right wheel speeds detected by the wheel speed detecting means, one of the left / right driving force adjusting means and the differential limiting means is selected. Driving force control selection means for
Driving force control means for controlling the left / right driving force adjusting means or the differential limiting means selected by the driving force control selecting means based on the left / right driving force control amount calculated by the control amount calculating means;
The driving force control selection means includes
When the driving force moving direction of the left / right driving force control amount calculated by the control amount calculating means and the wheel direction with the larger wheel speed among the left and right wheel speeds detected by the wheel speed detecting means are the same, Select the left and right driving force adjusting means,
When the driving force moving direction and the wheel direction with a small wheel speed are the same and the left / right driving force control amount is equal to or greater than a predetermined left / right driving force control amount, the differential limiting means is selected,
When the driving force moving direction and the wheel direction with the smaller wheel speed are the same and the left / right driving force control amount is less than a predetermined left / right driving force control amount, the right / left driving force adjustment selected immediately before Or a left and right driving force control apparatus characterized by maintaining the differential limiting means.   The driving force control selection means includes
  When the driving force moving direction and the wheel direction with the smaller wheel speed are the same, the left / right driving force control amount is less than the predetermined left / right driving force control amount, and the difference between the left and right wheel speeds is less than the predetermined wheel speed. 2. The left / right driving force control device according to claim 1, wherein the right / left driving force adjusting means or the differential limiting means selected immediately before is maintained. The driving force control selection means includes
From the state in which the driving force moving direction and the wheel direction with the smaller wheel speed are the same and the left and right driving force control amount is less than the predetermined control amount, the driving force moving direction is reversed left and right and simultaneously the direction of the left and right wheel speed difference is 3. The left and right driving force control device according to claim 1, wherein the differential limiting means is selected when the left and right are reversed. The driving force control selection means, the predetermined left and right driving force control amount to any setting controllable left driving force control amount limit from claim 1, wherein 3 of the right and left driving force adjusting means The left-right driving force control apparatus as described.

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