JP2701276B2 - Vehicle differential limiting control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a differential limiting control device for a vehicle, which is used for a differential device of an automobile and controls a differential limiting torque. (Prior Art) Conventional differential limiting control devices for vehicles include, for example, JP-A-62-103227 (Japanese Patent Application No. 60-244677) and JP-A-61-102.
An apparatus described in Japanese Patent Application No. 320 (Japanese Patent Application No. 59-223486) is known. The former conventional device is a vehicle differential limiting control device capable of controlling a differential limiting torque. It has progressive characteristics. The latter conventional device is a vehicle differential limiting control device capable of controlling the differential limiting torque, in order to prevent the inner wheel from sticking when turning, to perform large steering at a predetermined vehicle speed or less, a large accelerator opening, and a road surface μ. Is higher, the differential limiting torque is reduced. (Problems to be Solved by the Invention) However, in the former conventional device, since the differential limiting torque is generated in proportion to the difference between the rotational speeds of the right and left driving wheels, the inner wheel spin is slightly large during turning. When there is no difference between the rotational speeds of the left and right driving wheels, the differential limiting torque is small, and the driver is less likely to cause power drift. Further, in the latter conventional device, since the differential limiting torque is generated in proportion to the accelerator opening, one wheel slips on a split μ road (a road surface having different road surface friction coefficients between the left and right wheels). When the accelerator opening is small, for example, when the inner wheel spins during a turn, etc., a high differential limiting torque is not generated, and while the wheel idling is sufficiently suppressed, a high driving force is applied to the high μ road side or the outer wheel side. The problem of not being able to communicate. (Means for Solving the Problems) The present invention has been made for the purpose of solving the problems described above, and in order to achieve this object, the present invention has the following solution. The means for solving the present invention will be described with reference to the conceptual view of the claims shown in FIG. 1. The differential limiting clutch means 1 provided between left and right drive wheels and engaged by an external control force, and detects the state of the vehicle. Clutch control means 3 for controlling increase / decrease of the differential limiting torque based on the detection signal from means 2
In the differential limiting control device for a vehicle, comprising: an accelerator opening detecting means 201 as the detecting means 2;
And a left and right driving wheel rotational speed difference detecting means 202 for detecting a driving wheel rotational speed difference from each of the right and left driving wheel rotational speeds. The clutch control means 3 includes a differential limiting means which increases in proportion to the accelerator opening. Means for obtaining a torque command value; means for obtaining a differential limiting torque command value that increases in proportion to the difference between the rotational speeds of the left and right driving wheels; and calculating the sum of the two obtained differential limiting torque command values. It is characterized by having means for setting the result to the final differential limiting torque command value. (Action) When one wheel slips on the split μ road, or when the inner wheel spins when turning, the slip and spin increase when the accelerator is operated in the depressing direction, so that the accelerator opening is generally reduced. However, the final differential limiting torque command value is determined by the clutch control means 3 between the differential limiting torque command value using the left and right drive wheel rotational speed difference as a parameter and the differential limiting torque command value using the accelerator opening as a parameter. Because it is obtained by the sum, regardless of the accelerator opening,
The final differential limiting torque command value is determined mainly based on the differential limiting torque command value based on the left and right drive wheel rotational speed difference. During power drift traveling, the driver performs a depressing operation on the accelerator to make a turn using the sideslip of the drive wheels. Since the traveling is performed on a road with a high friction coefficient, the difference between the rotational speeds of the left and right drive wheels is small. However, the final differential limiting torque command value is determined by the clutch control means 3 between the differential limiting torque command value using the left and right drive wheel rotational speed difference as a parameter and the differential limiting torque command value using the accelerator opening as a parameter. Since it is obtained by the sum, the final differential limiting torque command value is determined mainly based on the differential limiting torque command value based on the accelerator opening regardless of the rotational speed difference between the left and right driving wheels. Therefore, the final differential limiting torque command value is determined with a high correspondence in which the two control elements are taken into account, that is, the sum of the differential limiting torque command values of the left and right drive wheel rotational speed differences and the accelerator opening. Therefore, it is possible to achieve both the suppression of slip on the split μ road and the suppression of spin of the inner ring at the time of turning, and the ease of power drift. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In describing this embodiment, a differential limiting control device for a rear wheel drive vehicle provided with a multi-plate friction clutch means operated by an external hydraulic pressure will be taken as an example. First, the configuration of the embodiment will be described. As shown in FIG. 2, a rear wheel drive vehicle to which the differential limiting control device D of the embodiment is applied includes a left front wheel 10, a right front wheel 11, an engine 12, a transmission 13, a propeller shaft 14, a differential device 15, A drive shaft 16 on the left wheel side, a drive shaft 17 on the right wheel side, a rear left wheel 18 and a rear right wheel 19 are provided, and the differential device 15 includes a drive input side propeller shaft 14 and a drive output side drive shaft 16. , 17 between the left and right wheels 18, 19
Is provided with a wet multi-plate friction clutch (differential limiting clutch means) 20 for limiting the differential of the clutch. The wet multi-plate clutch 20 is engaged by a control oil pressure P from a hydraulic pressure generator 30 which is an external device. As shown in FIG. 3, the differential limiting control device D of the embodiment is provided with a left rear wheel rotational speed sensor 43, a right rear wheel rotational speed sensor 44, and an accelerator opening degree sensor 45 as input sensors 40. A differential limiting control circuit 50 is provided as a module, and an electromagnetic proportional pressure reducing valve is used as a control actuator.
There are 60 provided. The left rear wheel rotation speed sensor 43 and the right rear wheel rotation speed sensor 44 are means for detecting the rotation speed of the left and right rear wheels 18, 19, which are drive wheels, and correspond to the left rear wheel rotation speed NRL from the sensor 43. The left rear wheel rotation speed signal (nrl) and the sensor 44 output a right rear wheel rotation speed signal (nrr) corresponding to the right rear wheel rotation speed NRR. The accelerator opening sensor 45 outputs an accelerator opening signal (a) corresponding to the accelerator opening A. The differential limiting control device 50 is a control circuit centered on an on-board microcomputer, and an input interface circuit.
51, a memory 52, a CPU (Central Processing Unit) 53, and an output interface circuit 54. The memory 52 of the differential limiting control circuit 50 stores an arithmetic expression (torque characteristic shown in FIG. 4) for the differential limiting torque ΔT _N (control oil pressure P _N ) with respect to the left and right driving wheel rotational speed difference ΔNrl and the accelerator opening. differential limiting relative degree A torque [Delta] T _A (control pressure P _A)
(The torque characteristic shown in FIG. 5) is set in advance. The electromagnetic proportional pressure-reducing valve 60 is provided in the hydraulic pressure generating device 30, and supplies hydraulic pressure of pump pressure supplied from a hydraulic pump 31 via a pump pressure oil passage 32 to a control current signal from a differential limiting control circuit 50. According to (i), the valve actuator controls the pressure of the control oil pressure P proportional to the magnitude of the command current value i *. Note that the control oil pressure P and the differential limiting torque T are in a relationship of T ・ P · μ · n · r · En; number of clutches r; average radius of clutch E; pressure receiving area. It is proportional to the oil pressure P. Next, the operation of the embodiment will be described. First, the operation flow of the differential limiting control in the differential limiting control circuit 50 will be described with reference to the flowchart shown in FIG. In step 100, the left rear wheel rotational speed NRL and the right rear wheel rotational speed NRR. The accelerator opening A is read. In step 101, a left / right driving wheel rotation speed difference ΔNrl is calculated from the left rear wheel rotation speed NRL and the right rear wheel rotation speed NRR read in step 100. The arithmetic expression is ΔNrl = NRL−NRR. In step 102, the differential limiting torque T _N which is proportional to the resulting left and right drive wheel rotation speed difference ΔNrl in step 101 is determined. The differential limiting torque T _N is obtained as a value that is linearly proportional to the increase in the rotational speed difference ΔNrl between the left and right driving wheels, as shown in the characteristic diagram of FIG. In step 103, the differential limiting torque T _A in proportion to the accelerator opening A read in step 100 is determined. The differential limiting torque T _A is obtained as a value that is linearly proportional to the increase in the accelerator opening A, as shown in the characteristic diagram of FIG. In step 104, the respective differential limiting torque T _N, the last from T _A differential limiting torque T is determined by calculation. The calculation formula of the final differential limiting torque T is as follows. In T = T _N + T _A step 105, the final differential limiting torque T is obtained command current value i * by the signal (i) is output. Next, the operation at the time of traveling will be described separately for one wheel slip (including inner wheel spin during turning) and power drift traveling. (A) When one wheel slips When one wheel slips on the split μ road or when the inner wheel spins when turning, the slip and spin increase when the access is operated in the depressing direction. I do. However, the final differential limiting torque T includes a differential limiting torque T _N for the left and right drive wheel rotation speed difference ΔNrl a parameter, since obtained by the sum of the differential limiting torque T _A for the accelerator opening degree A as a parameter , Regardless of the accelerator opening A,
Final differential limiting torque T is determined differential limiting torque T _N by the left and right drive wheel rotation speed difference ΔNrl mainly. Therefore, when one wheel slips on the split μ road, the engine differential is distributed to the high μ road side while suppressing the slip of the wheels on the low μ road by the high differential limiting torque T, thereby reducing the slip on the split μ road. The running performance of is improved
When the inner wheel spins during turning, the inner wheel spin is suppressed by the high differential limiting torque T, and turning performance is enhanced by the road surface grip by the inner and outer wheel grounding. (B) During power drift traveling During power drift traveling, the driver performs the accelerator depressing operation and turns using the sideslip of the drive wheels 18 and 19, which is performed when traveling on a road with a high friction coefficient. The difference ΔNrl is small. However, the final differential limiting torque T includes a differential limiting torque T _N for the left and right drive wheel rotation speed difference ΔNrl a parameter, since obtained by the sum of the differential limiting torque T _A for the accelerator opening degree A as a parameter , Regardless of the rotational speed difference ΔNrl between the left and right drive wheels, the differential limiting torque TA due to the accelerator opening _A
, The final differential limiting torque T is determined. Therefore, the differential limiting torque T corresponding to the accelerator work is obtained, and the power drift can be easily performed while controlling the drift by the accelerator depression amount. The embodiments of the present invention have been described in detail with reference to the drawings.
The specific configuration is not limited to this embodiment, and the present invention includes any design change or the like without departing from the scope of the present invention. For example, in the embodiment, an electromagnetic proportional pressure reducing valve is shown as an actuator, but an open / close electromagnetic valve or the like is used.
An example in which hydraulic pressure control is performed using a control signal as a duty signal may be adopted. Further, in the embodiment, the example in which the differential limiting torque is obtained by the wet multi-plate friction clutch has been described. However, the example may be such that the differential limiting torque is obtained by another clutch such as an electromagnetic clutch or a brake. (Effect of the Invention) As described above, in the differential limiting control device of the present invention, the increase / decrease control of the differential limiting torque is performed by controlling the differential limiting torque command value that increases in proportion to the accelerator opening. Means for calculating the differential limiting torque command value that increases in proportion to the difference between the rotational speeds of the left and right driving wheels, and calculating the sum of the two obtained differential limiting torque command values and calculating the final difference. Since the control is performed by the clutch control means having a means for setting the dynamic limiting torque command value, the final differential limiting is performed with high correspondence in which the two control elements of the rotational speed difference between the left and right driving wheels and the accelerator opening are mutually taken into account. The torque command value is determined, and the effect of achieving both the suppression of the slip on the split μ road and the suppression of the inner ring spin at the time of turning and the easiness of the power drift can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual view of a claim showing a vehicle differential limiting control apparatus according to the present invention, FIG. 2 is an overall view of an apparatus according to an embodiment of the present invention, and FIG. FIG. 4 is a view showing a differential limiting control device including a differential limiting torque characteristic diagram with respect to a rotational speed difference between left and right driving wheels set in a differential limiting control circuit of the embodiment, and FIG. FIG. 6 is a characteristic diagram of the differential limiting torque with respect to the accelerator opening set in the limiting control circuit. FIG. 6 is a flowchart showing the flow of the differential limiting control operation in the apparatus of the embodiment. 1 ... Differential limiting clutch means 2 ... Detecting means 201 ... Accelerator opening degree detecting means 202 ... Left and right driving wheel rotational speed difference detecting means 3 ... Clutch controlling means

Claims (1)

(57) [Claims] A differential limiting clutch means provided between the left and right driving wheels and engaged by an external control force, and a clutch control for increasing / decreasing a differential limiting torque based on a detection signal from a means for detecting a state of the vehicle. Means for controlling differential limiting for a vehicle, comprising: an accelerator opening degree detecting means as the detecting means; and a right and left driving wheel rotational speed difference detecting a driving wheel rotational speed difference from each of the right and left driving wheel rotational speeds. Detecting means for obtaining a differential limiting torque command value that increases in proportion to the accelerator opening, and a differential limiting torque command value that increases in proportion to the left and right drive wheel rotational speed difference. And a means for calculating the sum of the two determined differential limiting torque command values and using the result of the calculation as a final differential limiting torque command value. Control device.