JPH02175332A - Drive force distributed clutch control device for car - Google Patents

Abstract

PURPOSE:To enhance the running stability in turning at the time of high speed turning and the head swinging characteristic in turning at the time of low speed turning by controlling up or down the transmission torque according to the centripetal acceleration when quick deceleration is sensed, and by setting the control gain for the transmission torque so as to increase as the car speed is situated more to the high car-speed side. CONSTITUTION:A clutch control device as per existing invention includes a drive system clutching means 1 which generates a transmission torque by a controlling external force, and this clutching means 1 is controlled by a drive force distributed control means 3 on the basis of a signal given by a specified sensing means 2, and thus the transmission torque is controlled up or down. This is equipped with such sensing means 2 as a quick deceleration sensing means 201 for sensing quick decelerating condition of the car, a centripetal accel. sensing means 202 for sensing the centripetal accel. of the car, and a car speed sensing means 203 for sensing the car speed. The mentioned drive force distributed control means 3 controls up or down the transmission torque according to the centripetal acceleration when quick deceleration is sensed, and also the control gain for the transmission torque is increased as the car speed is situated more toward the high car-speed side.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a vehicle driving force distribution clutch control device that applies a differential limiting torque and a forward return driving force distribution torque according to a control external force according to predetermined control conditions. Regarding.

(Prior Art) Conventionally, as a driving force distribution clutch control device for a vehicle, for example, Japanese Patent Application Laid-open No. 63-78822 and Japanese Utility Model Application No. 63-2
A device described in Japanese Patent No. 2236 is known.

These devices determine that the vehicle is in a tuck-in state when braking or sudden deceleration occurs and the centripetal acceleration is large, and when the vehicle is in the tuck-in state, differential limiting torque is applied in accordance with the centripetal acceleration. The moment in the tuck-in direction that accompanies turning is canceled out by the moment in the opposite direction to the tuck-in direction that is generated with the application of the differential limiting torque, thereby effectively suppressing tuck-in that causes the vehicle to spin.

(Problem to be Solved by the Invention) However, in such conventional vehicle drive force distribution clutch control devices, it is difficult to apply differential limiting torque based on control characteristics that correspond only to the value of centripetal acceleration. Because of the It is not possible to achieve both stability when turning at low speeds and good turning performance when turning at low speeds.

In other words, if the transmission torque characteristic with respect to centripetal acceleration is set to a characteristic with a large control gain, tuck-in can be sufficiently suppressed during high-speed turns and cornering stability can be obtained.
When turning at low speeds, excessive tuck-in is suppressed, resulting in poor turning performance.

In addition, if the transmission torque characteristic with respect to centripetal acceleration is set to a characteristic with a small control gain, high turning performance using the tack-in moment can be obtained during low-speed turns, but tuck-in is not sufficiently suppressed during high-speed turns, resulting in poor turning stability. inferior to

The present invention has been made with a focus on the above-mentioned problems, and it is possible to improve turning stability during rapid deceleration and high centripetal acceleration turns where tuck-in occurs, and during high-speed turns where the driver's corrective steering ability is low. The objective is to develop a differential limiting control device that can achieve high turning performance during low-speed turns when the driver's corrective steering ability is high.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this purpose, the driving force distribution clutch control device for a vehicle of the present invention has been developed as shown in Fig. 1. As shown in the diagram corresponding to the complaint, a drive system clutch means 1 is installed in a drive system that distributes and transmits engine driving force to the front and rear or left and right drive wheels, and generates a transmission torque by an external control force, and a predetermined detection means 2. A driving force distribution clutch control device for a vehicle is provided with a driving force distribution control means 3 for controlling transmission torque to be increased or decreased based on a signal from the vehicle. , has a centripetal acceleration detection means 202 for detecting the centripetal acceleration of the vehicle, and a vehicle speed detection means 203 for detecting the vehicle speed, and when the driving force distribution control means 3 detects that the vehicle is in a sudden deceleration state,
In addition to controlling the transmission torque to increase or decrease according to the centripetal acceleration,
The present invention is characterized in that the control gain of the transmitted torque is increased as the vehicle speed increases or as the vehicle speed increases.

(Function) When turning at a low speed where a tough-in state occurs, the driving force distribution control means 3 sets the transmission torque characteristic to the centripetal acceleration to a characteristic with a small control gain due to the low vehicle speed.

Therefore, when turning at low speeds when the driver has high corrective steering ability, the moment in the opposite direction to the tuck-in direction generated by applying the transmitted torque is small (, By retaining the moment, high turning performance can be achieved by actively utilizing the tuck-in moment.

During a high-speed turn where a tuck-in condition occurs, the driving force distribution control means 3 sets a transmission torque characteristic with respect to centripetal acceleration to a characteristic with a large control gain due to the high vehicle speed.

Therefore, during high-speed turns when the driver's corrective steering ability is low, the moment in the tack-in direction accompanying the turn is canceled out by the moment in the opposite direction to the tack-in direction generated by applying the transmitted torque, and tuck-in is sufficiently suppressed. This provides stability when turning.

(Example) Hereinafter, embodiments 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 contact-wheel drive vehicle equipped with a multi-disc friction clutch mechanism operated by external hydraulic pressure will be taken as an example.

First, the configuration of the embodiment will be explained.

FIG. 2 shows an overall schematic diagram of the embodiment device, including a differential 10 and a multi-disc friction clutch machine Il! (Drive system clutch means) 11. It is equipped with a hydraulic pressure generator 12 and a control unit (driving force distribution control means) 13, and the input sensors 14 of the control unit 13 include a vehicle speed sensor 141 (vehicle speed detection means) and an accelerator opening sensor 14.
2 and a centripetal acceleration sensor 143.

Each configuration will be described below with reference to FIGS. 3 to 5.

The differential 10 has a differential function that creates a speed difference between the left and right axles according to the rotational speed difference in driving conditions where there is a difference in rotational speed between the left and right axles, and a differential function that equally distributes the engine driving force between the left and right drive wheels. This is a device with a driving force distribution function that distributes and transmits power.

The differential 10 is housed in a housing 16 that is attached to the vehicle body by a stud port 15, and includes a ring gear 17, a differential case 18, a pinion mate shaft 19, a differential pinion 20, and side gears 21 and 21'.

The differential case 18 includes a housing 16
It is rotatably supported by tapered roller bearings 22゜22゛.

The ring gear 17 is fixed to the differential case 1, meshes with a drive pinion 24 provided on the propeller shaft 23, and receives rotational driving force from the drive pinion 24.

The side gear 21.2bi includes a left wheel drive shaft 25 and a right wheel drive shaft 26, which are drive output shafts.
are provided for each.

The multi-disc friction clutch mechanism 11 is provided between the drive input section and the drive output section of the differential 10, and is a mechanism that generates a differential limiting torque based on the clutch engagement force generated by external hydraulic pressure.

The multi-plate friction clutch mechanism 11 is housed within a housing 16 and a differential case 18.
Multi-disc friction clutch 27.27', pressure ring 2
8.28', reaction plate 29.29',
It is equipped with a thrust bearing 30, 30, a spacer 31, 31', a bushing rod 32, a hydraulic piston 33, an oil chamber 34, and a hydraulic boat 35.

The multi-plate friction clutch 27.27° includes friction plates 27a, 27°a fixed to the differential case 18 in the rotational direction, and side gears 2+, 2+'.
Friction disks 27b, 2 fixed in the rotational direction to
7' b, and a pressure ring 2828" and a reaction plate 2 on both axial end faces.
9.29” are arranged.

The pressure ring 28, 28' is connected to the pinion mate shaft 19 as a member receiving the clutch engagement force.
As shown in FIG. 4, the fitting part is fitted to the shaft end 19a with a square cross section through square grooves 28a and 28'a, and the conventional torque proportional The structure is such that no thrust force is generated due to rotational differences, as is the case with differential differential limiting mechanisms.

The hydraulic piston 33 moves in the axial direction (to the right in the drawing) by supplying hydraulic pressure to the hydraulic port 35, and engages both multi-disc friction clutches 27, 27' according to the hydraulic pressure level. In the clutch 27, the engagement force is transmitted from the bushing rod 32 to the spacer 31 to the thrust bearing 30 to the reaction plate 29, and the clutch 27 is engaged by receiving the reaction force on the second day of pressure ring. The fastening reaction force from becomes the fastening force and the fastening is completed.

The hydraulic pressure generating device 12 generates a control hydraulic pressure P which becomes a clutch engagement force.
These are external devices that generate the hydraulic pump 40, pump motor 41. It includes a pump pressure oil passage 42, a drain oil passage 43, a control pressure oil passage 44, and an electromagnetic proportional pressure reducing valve 46 having a valve solenoid 45.

The electromagnetic proportional pressure reducing valve 46 is an actuator that performs hydraulic control to a control oil pressure P that is proportional to the current value of the control signal (i) from the control unit 13, and the control oil pressure P and the differential limiting torque TT are in a proportional relationship. be.

The control unit 13 is an electronic control circuit using an on-vehicle microcomputer, and includes an input interface circuit 131, a memory 132 such as RAM and ROM, and a CPU.
+33. An output interface circuit 134 is provided.

The vehicle speed sensor 141 is a sensor that detects a vehicle speed V by detecting the rotation speed of a transmission output shaft, the rotation speed of one or more driven wheels, a Doppler radar type ground vehicle speed meter, etc., and outputs a vehicle speed signal (V). be.

The accelerator opening sensor 142 is provided at the throttle valve position of the engine, detects the accelerator opening Acc, and outputs an accelerator opening signal (AcC>).

The centripetal acceleration sensor 143 is a sensor that directly detects centripetal acceleration Y9 using a G sensor and outputs a centripetal acceleration signal (Y9).

Incidentally, instead of using the vehicle speed sensor 141 and the centripetal acceleration sensor 143, a right front wheel speed sensor and a left front wheel speed sensor are provided as described in Japanese Patent Laid-Open No. 63-78822, and the vehicle speed V and centripetal acceleration Y9 are , V = min (WL, L) Y9= may be determined by the arithmetic expression "v xl WL-WPl".

Next, the effect will be explained.

First, the flow of the differential limiting control operation in the control unit 13 will be explained with reference to the flowchart shown in FIG.

In step a, vehicle speed V, accelerator distance ACC+centripetal acceleration Y9, and TUCKFLG (tuck flag), which is information indicating whether tuck-in suppression control is being performed, are read.

In step b, the accelerator opening degree Aco read this time is
and the accelerator opening degree A read in one control cycle or several control cycles before. The accelerator opening differential individual is calculated based on the set time t and the set time t using the following formula.

A cc" (A cc - A o ) / dt In step C, it is determined whether the vehicle is accelerating at a constant speed or decelerating by determining whether the accelerator opening degree differential value Acc is positive or negative.
When c≧0 and during constant speed/acceleration, Ac in step d
eFLG = 0, human. . When the speed is decelerating at <0, step e L8 is made and A ccFLG is set to 1.

In the next step f, it is determined whether tuck-in control is being performed depending on whether TUCKFLG=1.

Then, when TUCKFLG = 0 and tuck-in control is not in progress, the start condition for tuck-in suppression control is determined in steps 9 to STEP J, and TUCKFLG
When the tuck-in control is in progress with =1, the conditions for canceling the tuck-in suppression control in step n and step Q are determined.

The conditions for starting the drag-in suppression control are as follows: (1) The accelerator opening degree Acc is smaller than 〇 to a set value close to zero (Step 9).

■ AccFLG = +, which is the direction of accelerator release (step h).

■ l Accl >A, and the speed is close to the accelerator release speed caused by sudden foot release of the accelerator, that is, the vehicle is in a rapid deceleration state (step 1).

■ Y9≧Y, and the vehicle is turning with high centripetal acceleration (step J).

Only when all these conditions are satisfied, the process proceeds to step k and step Q, and tuck-in suppression control is started.

If even one of the tuck-in suppression control start conditions is not satisfied, the process proceeds to step m, and the accelerator opening amount value A
CC+ Based on the accelerator opening Acc and vehicle speed V, and the maps shown in Figures 6a, 6b, 6c, and 6d, the differential limiting torque is determined and normal differential limiting control is performed. It will be done.

On the other hand, when all the tuck-in suppression control start conditions are satisfied, the process advances to step TUCKFLG == 1 indicating that tuck-in suppression control is in progress, and step i
Then, differential limiting torque T is determined by vehicle speed V and centripetal acceleration Y9.
, is determined and the tartar pull-in suppression control is performed.

The differential limiting torque T, is: d = f (V, Y9) 2 x V X (Yg Y2) = K v , and Y,<Y.

Then, when the calculation formula for the differential limiting torque T is plotted in a characteristic diagram, as shown in FIG. 7, at low vehicle speeds, the gain corresponding to the vehicle speed is small and the differential limiting torque , the increase ratio is small, and when the vehicle speed is high, the gain corresponding to vehicle speed is large, and the
9, the differential limiting torque T1 has a large increase ratio.

As shown in Fig. 8, the multi-connection corresponding gain Kv gives a value that increases in proportion to the increase in vehicle speed V in the low and medium speed range up to a predetermined vehicle speed v0, and when the vehicle speed exceeds the predetermined vehicle speed v0. In the high speed region, a constant upper limit value is given to prevent sudden changes in vehicle behavior due to sudden increases in torque, etc.

Further, during the tuck-in suppression control, the process proceeds from step f to step n and subsequent steps, and the conditions for canceling the tuck-in suppression control are determined.

The conditions for canceling the tuck-in suppression control are as follows: (1) The accelerator opening degree ACC decreases to the set value by more than 〇 due to the pedal depression operation (step n).

■ Shift from turning with high centripetal acceleration to straight running and Y
9≦Y2 (step 0).

If the ICE controller does not satisfy both conditions at the same time, the process proceeds to step β, and tuck-in suppression control continues, and only when both conditions are simultaneously satisfied, the process proceeds to step p, and the TU
CKFLG=O is set, the tuck-in suppression control is canceled, and the routine proceeds to step m, where normal differential limiting control is performed.

Next, the operation will be explained separately for normal differential limiting control and tuck-in suppression control.

(b) When driving in a driving pattern other than sudden deceleration and turning during normal differential limiting control and when driving does not satisfy the start conditions for tuck-in suppression control, step m
Normal control is performed, and vehicle speed V and accelerator opening Ac
A differential limiting torque corresponding to c can be obtained, high-speed running stability and high-acceleration running performance can be achieved, and high control responsiveness can be achieved by including the accelerator opening degree differential value Acc in the control conditions.

(B) At the time of tuck-in suppression control The operation when the starting conditions for tuck-in suppression control are satisfied during a sudden deceleration turn will be explained separately for low-speed turning and high-speed turning.

・During a low-speed turn Even at low speed, the turning radius is small and a high centripetal acceleration Y9 occurs.When turning to satisfy the start condition for tuck-in suppression control, the vehicle speed V is low, so the centripetal acceleration Y9 is generated.
The differential limiting torque characteristic is set to a characteristic with a small heavy speed corresponding control gain KV.

Therefore, when turning at low speeds when the driver's corrective steering ability is high, the large moment in the tuck-in direction that accompanies the turn is generated due to an increase in the road surface transmitted driving force on the inner wheel side of the turn due to the application of differential limiting torque. The moment in the opposite direction to the tuck-in direction is small, and the moment in the tuck-in direction, that is,
By retaining a moment in the oversteer direction, high turning performance can be achieved by actively utilizing the tuck-in moment.

・During a high-speed turn that satisfies the start conditions for tuck-in suppression control during a high-speed turn, the vehicle speed V is high, so the vehicle speed corresponding control gain K is set as a differential limiting torque characteristic for the centripetal acceleration Y9.
The characteristic is set to have a large value of v.

Therefore, during high-speed turns when the driver's corrective steering ability is low, the moment in the tuck-in direction accompanying the turn is different from the tack-in direction generated by the increase in the road surface transmitted driving force on the inner wheel side of the turn due to the application of differential limiting torque. It exhibits a counteracting effect by the moment in the opposite direction, sufficiently suppressing tuck-in, and providing stability in turning without causing the vehicle to spin.

In this way, when turning when a tuck-in occurs, the driver's corrective steering ability is taken into consideration, and vehicle speed conditions are added to determine whether the driving condition is focused on turning ability or stability. The control gain of the tuck-in suppression control is controlled to be different during low-speed turns when the driver has high steering ability and during high-speed turns when the driver's corrective steering ability is low. When turning at high speed, it is possible to achieve stability in turning by sufficiently suppressing tank-in, and when turning at low speed, it is possible to achieve high turning stability by actively utilizing tuck-in.

Although one embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and restrictions may be added or changed without departing from the gist of the present invention. are also included in the present invention.

For example, in the embodiment, a tuck-in condition that occurs during a sudden deceleration during a turn with high centripetal acceleration is detected by monitoring the accelerator opening degree and detecting the sudden deceleration by releasing the foot from the accelerator pedal. The sudden deceleration state may be detected by a pressure sensor or a longitudinal acceleration sensor, or may be detected by a combination of an accelerator operation and a brake operation.

Further, the control content of the normal differential limiting control when the tuck-in suppression control is not performed is not limited to the embodiment, and may be controlled based on other driving conditions such as the difference in rotational speed of the left and right wheels. .

In addition, in the embodiment, an example of a differential limiting clutch that limits the differential between the left and right drive wheels is shown as a drive system clutch means, or a drive force distribution that can control the drive force distribution ratio between the front and rear wheels of a four-wheel drive vehicle. The same applies to clutches.

In this case, by distributing the driving force to the 4-wheel drive side when turning when a tuck-in is predicted to occur, the braking force from the engine brake at the time of tuck-in is distributed to the front and rear wheels, and the tire's road grip is at its limit. This increases the tuck-in that would otherwise occur when engine braking is strong in two-wheel drive mode.

(Effects of the Invention) As described above, in the vehicle driving force distribution clutch control device of the present invention, the detection means includes a sudden deceleration detection means for detecting a sudden deceleration state of the vehicle, and a sudden deceleration detection means for detecting a sudden deceleration state of the vehicle, and a centripetal acceleration of the vehicle. The driving force distribution control means controls the transmission torque to be increased or decreased in accordance with the centripetal acceleration when a sudden deceleration is detected. In addition, since the control gain of the transmitted torque is increased as the vehicle speed increases, sufficient tuck-in can be achieved during rapid deceleration and high centripetal acceleration turns where tuck-in occurs, and during high-speed turns where the driver's corrective steering ability is low. The suppression can improve turning stability, and when making low-speed turns where the driver's corrective steering ability is high, tuck-in can be actively used to achieve high turning performance.

[Brief explanation of the drawing]

FIG. 1 is a claim-corresponding diagram showing a driving force distribution clutch control device for a vehicle according to the present invention, FIG. 2 is an overall schematic diagram showing a differential limiting control device according to an embodiment, and FIG. 3 is a diagram showing an embodiment of the device. 4 is a sectional view showing the differential section, FIG. 4 is a view taken in the direction of the arrow in FIG. 3, FIG. 5 is a view showing the hydraulic pressure generator and control device of the embodiment device, FIG. 6th d
The figure shows a map of the differential limiting control characteristics during normal operation without tuck-in suppression control, Figure 7 shows the differential limiting torque characteristic during tuck-in suppression control, Figure 8 shows the iMJ gain characteristic on the vehicle speed side, and Figure 9 FIG. 2 is a flowchart showing the flow of differential limiting control operation in the embodiment device. 1... Drive system clutch means 2... Detection means 20? --Sudden deceleration detection means 202...Centripetal acceleration detection means 203...Vehicle speed detection means 3...Driving force distribution control means

Claims (1)

[Claims] 1) A drive system clutch means provided in a drive system that distributes and transmits engine driving force to front and rear or left and right drive wheels, and that generates transmission torque by an external control force, and a signal from a predetermined detection means. A driving force distribution clutch control device for a vehicle is provided with a driving force distribution control means for controlling transmission torque to increase or decrease based on the detection means, wherein the detecting means includes a sudden deceleration detecting means for detecting a sudden deceleration state of the vehicle, and a sudden deceleration detecting means for detecting a sudden deceleration state of the vehicle, The vehicle has a centripetal acceleration detection means for detecting the centripetal acceleration, and a vehicle speed detection means for detecting the vehicle speed, and the driving force distribution control means increases or decreases the transmitted torque in accordance with the centripetal acceleration when a sudden deceleration state is detected. Further, a driving force distribution clutch control device for a vehicle is characterized in that the control gain of the transmission torque is increased as the vehicle speed becomes higher.