JPS62134339A - Device for controlling driving system clutch for vehicle - Google Patents

Abstract

PURPOSE:To improve turning performance by providing a means for carrying out a control so that the higher the vehicle speed gets or the larger the steering angle becomes, the greater a clutch engaging force is made, and gradually varying a transfer ratio when said vehicle makes a turn. CONSTITUTION:In the captioned device, a driving system clutch means 4 is provided in between the driving input part and the driving output part of a power dividing device 3 for distributing and transmitting the driving force of an engine to right and left driving wheels 1, 2, and the clutch engaging force of said means 4 is controlled in its increase and decrease according to the output signal of an input sensor 5 for detecting a vehicle condition. As the input sensor 5, a steering angle sensor 501 and a vehicle speed sensor 502 are provided. And, the output signals of these sensors 501, 502 are inputted into a control means 6, to carry out a control so that the higher the vehicle speed gets or the larger the steering angle becomes, the greater the clutch engaging force is made.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is used in a power split device such as a differential device or a transfer device of a four-wheel drive vehicle, and is used to control differential limiting torque and driving force distribution torque. The present invention relates to a drive system clutch control device for a vehicle that changes speed.

(Prior Art) As a conventional differential limiting device, one shown in FIG. 9, for example, is known. "Nissan Skyline Service Bulletin No. 446 rSK-2", October 9, 1982
(Published by Nissan Motor Co., Ltd.) This conventional bag m has a pair of side gears 101 that are arranged facing each other inside a differential case 100 and are provided with left and right axle shafts.

101', a pinion mate shaft 103 disposed between the side gears lot and 101' and provided with a pinion mate gear 102 that meshes with the side gears 101 and 101'; pinion mate shirt) 103
Pressure rings 104, 10 are cam-coupled with the ends of
4', and friction clutches 105, 105, which are disposed between the pressure rings 104, 104' and the differential case 100, and frictionally engage the side gears 101, 101' and the differential case lOO.
′.

Incidentally, the friction clutches 105, 105' include friction discs 106, 106' fixed to the side gears toi, ioi', and a differential case 10.
Friction plates 107, 107 fixed on the 0 side
Dishes friction plates 108, 108 with disc spring structure that apply initial torque to the clutch
It was composed of.

Therefore, the friction clutch 105.105 in the conventional device
The clutch engagement force to ' is caused by the initial torque by the dished friction plates 108, 108', the vibration pushed open by the cam action, and the jarrings 104, 1.
This is due to the pressing force from 04', and looking at the transfer ratio characteristics, as shown in Figure 10, the characteristic line A is a combination of the initial torque a and the pressing force due to cam f'+. was.

Furthermore, the transfer ratio refers to the torque ratio between the high driving force side torque TH and the low driving force side torque TL, and T H / T
It is expressed by the formula t.

(Problem to be Solved by the Invention) However, in such conventional differential limiting devices, the transfer ratio, which is the slope of the diagram, is uniquely determined by the device settings. When a high transfer ratio is set, differential limiting torque is generated at the beginning of a turn when the rotational speed difference begins to occur between the left and right wheels, and a large drive torque is transmitted from the outer wheel to the inner wheel, which is the lower speed side, resulting in an understeer tendency. Furthermore, in the later stages of a turn, the wheel load moves from the inner wheel to the outer wheel, so the slip of the inner wheel causes a large amount of drive torque to be transmitted to the outer wheel, resulting in a so-called reverse steer characteristic. The turning trajectory of the vehicle was as shown by the dotted line B in FIG.

In addition, when setting a low transfer ratio, although the aforementioned understeer at the beginning of a turn is reduced, the differential limiting torque is insufficient in the later stages of a turn, and the grip force of the heavy wheels on the road surface is small, making it difficult to corner while accelerating. The problem was that it was not possible to do so.

(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 present invention has adopted the following solving means. .

The solution of the present invention will be described with reference to the claim conceptual diagram shown in FIG. A drive system clutch means 4 that is provided between the drive output section and the drive output section and generates a transmission torque according to the clutch engagement force from the outside, an input sensor 5 that detects the vehicle condition, and an input from the input sensor 5. A drive system clutch control device for a vehicle comprising: a control means 6 that outputs a control signal for increasing or decreasing clutch engagement force based on a signal; the input sensor 5 includes a steering angle sensor 501 and a vehicle speed sensor 502; Means 6 is a means for controlling the clutch engagement force to increase as the vehicle speed increases and as the steering angle increases.

(Function) Therefore, in the vehicle drive system clutch control device of the present invention,
As mentioned above, by controlling the clutch engagement force to increase as the vehicle speed increases and as the steering angle increases, the transfer ratio changes from the time of corner entry in accordance with the vehicle speed and steering angle conditions. It changes sequentially until exiting the corner, and good turning performance can be obtained.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, an example will be taken of an automatic lj river motion limiting clutch control device equipped with a multi-disc friction clutch means operated by external hydraulic pressure.

First, the configuration of the embodiment will be explained.

As shown in FIGS. 2 to 4, the embodiment device includes a differential device (power split device) 10, a multi-disc friction clutch means (drive system clutch means) 11, a hydraulic pressure generator 12, and a control unit (W control unit). means) 13 and an input sensor 14, and each configuration will be described below.

The differential device 10 has a differential function of providing a speed difference between the left and right wheels according to the rotational speed difference in a driving state where a rotational speed difference occurs between the left and right wheels, and a differential function that equalizes the engine driving force to the left and right driving wheels. This is a device that has a driving force distribution function that distributes and transmits the driving force.

This differential device 10 is housed in a housing 16 that is attached to a small body by a stud port 15, and includes a ring gear 17, a differential case 18,
It includes 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 connected to a differential case 18.
is fixed to the drive pinion 24 provided on the propeller shaft 23 and +! As a result, rotational driving force is input from this drive pinion 24.

The side gears 21, 21' include a left wheel drive shaft 25 and a right wheel drive shaft 2, which are drive output shafts.
6 is provided for each.

The multi-disc friction clutch means 11 is provided between the drive input section and the drive output section of the differential device IO, and is a means to which clutch engagement force is applied by external hydraulic pressure and generates a differential limiting torque.

This multi-disc friction clutch means 11 is housed within a housing 16 and a differential case 18, and includes a multi-disc friction clutch 27, 27', a pressure ring 28, 28', and a reaction plate 29.
．． 29', thrust bearing 30.30' spacer 31.3
1', bushing rod 32, hydraulic piston 33.7, chamber 34. A free pressure port 35 is provided.

The multi-plate friction clutch 27.27' has friction plates 27a, 27'a fixed in the rotational direction to the differential case (drive input part) 18, and fixed in the rotational direction to the side gear (drive output part) 21.21'. It is composed of friction disks 27b and 27'b, and pressure rings 28 and 28' are provided on both axial end faces.
and reaction plates 29, 29' are arranged.

The pressure ring 28, 28' is provided in a fitted state to the pinion mate shirt 19 as a member receiving the clutch fastening force, and the fitting part has a rectangular cross section as shown in FIG. The shaft end portion 19a is fitted into the shaft end portion 19a through square grooves 28a, 28'a, and the structure is such that no thrust force is generated due to a rotational difference, as in the conventional torque proportional differential limited r stage.

1111 The hydraulic piston 33 moves in the axial direction (to the right in the drawing) by supplying hydraulic pressure to the hydraulic port 35.

Both multi-disc friction clutches 27 and 27' are engaged according to the oil pressure level, and one multi-disc friction clutch 27 is
The fastening force is transmitted from the bushing rod 32 to the spacer 31 to the thrust bearing 30 to the reaction plate 29, and the pressure ring 28 is used to receive the reaction force, and the other multi-plate friction clutch 27' receives the fastening reaction force from the housing 16. becomes the tightening force and is tightened.

As shown in FIG. 4, the hydraulic pressure generating device 12 is an external device that generates hydraulic pressure for clutch engagement force, and is a hydraulic pump 40.
, a pump motor 41, 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 as a valve actuator.
It is equipped with

The pump motor 41 is a motor that is activated or deactivated by a motor signal (m) from the control unit 13, and is activated or deactivated when the vehicle is running and there is a possibility that differential restriction is being performed or differential restriction is being performed. When the vehicle is stopped, a motor signal (m) is output when the vehicle is energized, and when no differential restriction is required, such as when the vehicle is stopped, a motor signal (m) is output when the vehicle is not energized.

The electromagnetic proportional pressure reducing valve 46 converts the hydraulic oil at the pump pressure supplied from the hydraulic pump 40 via the pump pressure oil line 42 to the control current signal (i) from the control unit 13.
The control current signal ( i) is output to the valve solenoid 45 of the electromagnetic proportional pressure reducing valve 46.

In addition, the control oil pressure P and the differential limiting torque T are TCX:P-
μmn-r-A n: number of clutches r; clutch average radius A; pressure receiving area; differential limiting torque T is proportional to control oil pressure P.

The control unit 13 uses an on-vehicle microcomputer, and includes an input circuit 131, a RAM (random, access, memory) 132, a ROM (read,
It is equipped with a CPU (central processing unit) 134, a clock circuit 135, and an output circuit 136.

Incidentally, as the input sensor 14, a steering angle sensor 141 and a vehicle speed sensor 142 are provided.

The input circuit 131 is a circuit that converts the input signals (θ) and (V) from the input sensor 14 into signals that can be processed by the CPU.

The RAM 132 is a readable and writable memory, and input signals from the respective sensors 141 and 142 are written into the RAM 132, and information during calculation by the CPU 134 is written therein.

The ROM 133 is a read-only memory in which information necessary for arithmetic processing by the CPU 134 is stored in advance, and is read out from the CPU 134 as necessary.

The CPU 134 is a device that performs arithmetic processing on various input information according to predetermined processing conditions.

The clock circuit 135 is a circuit that sets the calculation processing time of the CPU 134.

The output circuit 136 is a circuit that outputs a control current signal (i) to the valve solenoid 45 based on a calculation result signal from the CPU 134.

The steering angle sensor 141 is a sensor that detects a steering angle of 0 and outputs a steering angle signal (θ) according to the steering angle θ.

The vehicle speed sensor 142 is a sensor that detects the vehicle speed and outputs a vehicle speed signal (V) according to the vehicle speed.

Note that the steering angle sensor 141 and the vehicle speed sensor 142 are used as sensors for searching the control current value 1 from a control characteristic map preset in the control unit 13.

Moreover, in the ROM 133 of the control unit 13,
A two-dimensional control characteristic map based on vehicle speed V and steering angle O as shown in FIG. 5 or 6 is set,
The control characteristic map shown in FIG. 5 is a control characteristic map in which the control current value l (=control oil pressure P) increases as the vehicle speed V increases and as the steering angle 0 increases, and the control characteristic map shown in FIG. MAP has a characteristic that prevents the differential limiting torque T from being applied until a predetermined vehicle speed vO in order to prevent an increase in steering force due to tight corner braking during low-speed large turning, as shown in Fig. 5 above. This is an example of adding it to the control characteristic map.

Next, the operation of the embodiment will be explained.

First, let us explain the operation of the embodiment and the operational flow of the differential limiting control in the seventh section.
This will be explained using the flowchart shown in the figure.

When driving straight and turning, step 200 → step 20
1→Step 202, and in Step 202, a control current signal (i) based on a control current value l based on the control characteristic map is output.

Incidentally, in step 200, the steering angle sensor 141. This is a step of reading input signals (0) and (V) from the vehicle speed sensor 142, and step 201 is the input signal (θ) read in step 200.

This is a search step in which the control current value l is searched from the control characteristic map using (V).

Next, the effects during cornering will be described.

When entering a corner from straight running, the vehicle speed V is low and the steering angle 0 is almost zero, so the control TLfi signal (i) based on the current value 1 = 0 of the control circuit 4B is output, and the differential limiting torque T is hardly generated. Next, from the time of corner entry to the initial stage of turning, as the steering angle θ increases, the control current value i* changes from 18=0 to i''=small, and the differential limiting torque T increases slightly.

However, the differential limiting torque T at the beginning of a turn is small and is close to that of an ordinary differential device, and the transfer ratio is also low, close to l, so that the tendency for understeer at the beginning of a turn is prevented.

From the mid-turn to the late-turn, as the steering angle O and vehicle speed increase, the control current value 1' changes from i''=small to 1.
The width changes from 7=width to i"=large, and the differential limiting torque T also increases.

Therefore, the transfer ratio changes sequentially from a low transfer ratio to a high transfer ratio, which ensures sufficient wheel grip on the road surface, enables cornering with high cornering force, and allows you to exit corners while accelerating. It can also be used for sports-like cornering.

In other words, as shown by the solid line C in FIG. 8, the turning locus is such that the tendency to oversteer remains to some extent in the later stages of the turn, but the understeer tendency in the early stages of the turn is eliminated.

As described above, in the differential limiting clutch control device of the embodiment, the multi-plate friction clutch means 27 performs differential limiting as the vehicle speed V increases and as the steering angle 0 increases.
27' is configured to increase the engagement pressure, so the transfer ratio changes sequentially from the time the corner is entered to the time the corner is exited, depending on the vehicle speed and steering angle conditions, thereby preventing the tendency of understeer at the beginning of a turn. It is possible to achieve both this and an increase in cornering force in the latter half of the turn.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified even if there are design changes within the scope of the gist of the present invention. included.

For example, in the embodiment, an example of a differential limiting clutch control device is shown, but it can also be applied to a transfer clutch that changes the drive force distribution ratio (transfer ratio) of a transfer device that distributes the drive force of a four-wheel drive vehicle. In this case, at the beginning of the turn, the vehicle is close to a two-wheel drive state, and a power slide is possible, and at the end of the turn, the vehicle is close to a four-wheel drive state, and the cornering force is high, resulting in a high limit speed.

In addition, in the embodiment, an example of a control characteristic map using only vehicle speed as a vehicle speed condition was shown, but it may also be a vehicle speed condition that takes vehicle acceleration and accelerator opening into consideration in addition to vehicle speed. The accelerator opening degree may also be used.

Further, in the embodiment, an electromagnetic proportional pressure reducing valve is shown as an actuator, but an example in which an electromagnetic valve that opens and closes or the like may be used to perform hydraulic control by using a control signal as a duty signal may also be used.

(Effects of the Invention) As explained above, in the vehicle drive system clutch control device of the present invention, the clutch engagement force is increased as the vehicle speed increases and as the steering angle increases. Therefore, the transfer ratio changes sequentially from the time the vehicle enters the corner to the time the vehicle exits the corner, corresponding to the vehicle speed conditions and the steering angle conditions, resulting in the effect that good turning performance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a claim showing a drive system clutch control device for a vehicle according to the present invention, FIG. 2 is a cross-sectional view showing a differential device incorporating a differential limiting means of an embodiment of the device of the present invention, and FIG. FIG. 2 is a Z-direction arrow view, and FIG. 4 is a diagram showing a hydraulic pressure generating device and a control device of the embodiment device. 5 and 6 are two-dimensional control characteristic maps of control current values stored in advance in the control unit of the embodiment device, and FIG. 7 is a flowchart showing the flow of differential limiting control operation of the embodiment device. , Figure 8 is a characteristic diagram of the turning trajectory,
FIG. 9 is a sectional view showing a conventional differential limiting device, and FIG. 10 is a transfer ratio characteristic diagram of the conventional device. 1.2... Drive wheel 3... Power split device 4... Drive system clutch means 5... Input sensor 501... Steering angle sensor 502... Vehicle speed sensor 6... Control means

Claims (1)

[Claims] 1) A power split device that distributes and transmits engine driving force to front and rear or left and right drive wheels, and a clutch that is provided between a drive input section and a drive output section of the power split device and that is connected to an external clutch. A drive system clutch means that generates a transmission torque according to the engagement force, an input sensor that detects the vehicle condition, and a control means that outputs a control signal that increases or decreases the clutch engagement force based on the input signal from the input sensor. In the drive system clutch control device for a vehicle, the input sensor includes a steering angle sensor and a vehicle speed sensor, and the control means is configured to control the clutch engagement force to increase as the vehicle speed increases and as the steering angle increases. A drive system clutch control device for a vehicle, characterized in that it is a means for controlling a vehicle.