JPH07115597B2 - Vehicular differential limiting controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle differential limiting control device that applies a control external force to differential limiting means and controls differential limiting according to a predetermined control condition.

(Prior Art) As a conventional differential device including a differential limiting control means, for example, "Automotive Engineering Complete Book, Vol. 9 Power Transmission Device" (1980)
Devices such as those described on pages 321 to 324 of Sankaido Co., Ltd. on November 15 are known.

In this conventional device, a multi-disc friction clutch provided between a differential case and a side gear is used as a differential limiting means, and a cam mechanism of a pinion mate shaft portion due to a rotational speed difference between the left and right wheels is applied to the multi-disc friction clutch. The thrust force generated in 1 is used as a clutch engaging force, and the clutch engaging force is used to generate the differential limiting torque. still,
Here, the differential limiting means means a means for exerting a differential limiting function, and a device called a limited slip differential normally distinguishes both as a differential device having a built-in differential limiting means, and simply refers to the difference. When it is described as a moving device (differential means), it means an ordinary differential device (conventional differential) having no limiting function.

Further, as a differential limiting control device for increasing / decreasing the differential limiting torque according to an input signal from an input sensor for detecting a vehicle state, for example, Japanese Utility Model Laid-Open No. 59-70953 and Japanese Patent Laid-Open No. 59-19933.
The devices described in Japanese Patent Publication No. 1 and the like are known.

(Problems to be Solved by the Invention) However, in such a conventional device, although the differential limiting torque can be obtained according to the rotational speed difference between the left and right wheels, the wheel slip state, etc., Since the differential limitation is not related to anything at all, there is no correspondence to the driver's intention, vehicle condition, or running state. There is a problem that the differential limiting is performed when the limiting is not necessary, the differential limiting torque is too large or too small, and the differential limiting torque changes when it is not desired to change. .

For example, even when the vehicle is traveling at the same vehicle speed, the differential limitation is uniquely made even though the intention of the driving vehicle varies depending on the gear position. Further, even if the accelerator depression amount is the same, although the wheel drive torque differs depending on the gear position, the differential limitation is uniquely made.

Further, when the gear position is set to the 2nd speed and the vehicle is traveling by accelerating in the turning direction, the turning traveling feeling is deteriorated by the differential limiting torque which changes with the increase of the vehicle speed.

(Means for Solving Problems) The present invention has been made for the purpose of solving such conventional problems, and in order to achieve this object, the present invention provides the following means for solving the problems. did.

The solution means of the present invention will be described with reference to the conceptual diagram of claims shown in FIG. 1. A differential means 3 for distributing and transmitting an engine driving force to left and right drive wheels 1 and 2 while allowing a differential, and the differential means. 3 is provided between the drive input unit and the drive output unit 3 and is a differential limiting unit 4 for generating a differential limiting torque by an external control force.
And a control means 6 for outputting a control signal for increasing / decreasing the differential limiting torque based on an input signal from the input sensor 5, and a control means 6 for a vehicle. As the input sensor 5, a gear position sensor 50 for detecting the gear position of the transmission
1, the control means 6 generates different differential limiting torque depending on the gear position, and the differential limiting torque has a lower value when the gear position is in the low speed stage and the reverse stage than in the middle and high speed stages. The feature is that

(Operation) During traveling, the gear position of the transmission is detected by the input signal from the gear position sensor 501. And
The control means 6 outputs a control command to the differential limiting means 4 to obtain a differential limiting torque having a lower value when the gear position is in the low speed stage and the reverse stage than in the middle and high speed stages, and the gear position is in the middle stage. At the high speed stage, a control command for obtaining a higher differential limiting torque than at the low speed stage and the reverse stage is output to the differential limiting means 4.

Therefore, at low speeds and reverse speeds that are often used for garage entry, the differential limiting torque that limits the differential between the left and right drive wheels 1 and 2 is kept low, ensuring a small turning performance by differential. , Garage entry operation is easily performed.

In addition, at the medium speed, which is often used for sports-like running such as overtaking, a high differential limiting torque that limits the differential between the left and right drive wheels 1 and 2 is applied, In addition, even if you suddenly operate the accelerator during turning, you can turn around the course you are aiming for while suppressing tack-in, etc., and when overtaking, you can ensure smooth driving overtaking by ensuring sufficient driving force on the left and right drive wheels 1 and 2. .

Also, at high speeds that are often used when traveling at high speeds, high differential limiting torque that limits the differential between the left and right drive wheels 1 and 2 is applied, which reduces back swinging and allows high-speed straight traveling. It is possible to drive with excellent stability.

(Examples) Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In describing this embodiment, an automobile differential limiting control device equipped with a multi-plate friction clutch means that is operated by an external hydraulic pressure will be taken as an example.

First, the configuration of the embodiment will be described.

As shown in FIGS. 2 to 4, the device of the embodiment includes a differential device (differential means) 10, a multi-plate friction clutch means (differential limiting means) 11, a hydraulic pressure generator 12, a control unit (control means). ) 13 and an input sensor 14, 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 in accordance with the difference in rotation speed in a traveling state in which a difference in rotation speed occurs between the left and right wheels, and the engine driving force is applied to the left and right drive wheels. It is a device having a driving force distribution function for distributing and transmitting to distribution.

The differential device 10 is housed in a housing 1 attached to a vehicle body by a stud bolt 15, and includes a ring gear 1, a differential case 18, a pinion mate shaft 19, a differential pinion 20, side gears 21, 21 '.
Is equipped with.

The differential case 18 is rotatably supported on the housing 16 by Taber roller bearings 22 and 22 '.

The ring gear 17 is fixed to the differential case 18, meshes with a drive pinion 24 provided on the propeller shaft 23, and a rotational driving force is input from the drive pinion 24.

The side gears 21 and 21 'are respectively provided with a left wheel side drive shaft 25 and a right wheel side drive shaft 26 which are drive output shafts.

The multi-disc friction clutch means 11 is provided between the drive input portion and the drive output portion of the differential device 10, is given a clutch engagement force by an external hydraulic pressure, and generates a differential limiting torque.

The multi-disc friction clutch means 11 is housed in the housing 16 and the differential case 18, and comprises the multi-disc friction clutches 27, 27 ', pressure rings 28, 28', reaction plates 29, 29 ', thrust wheel bearings. 30, 30 ',
Spacers 31, 31 ', push rod 32, hydraulic piston 3
3, equipped with an oil chamber 34 and a hydraulic port 35.

The multi-plate friction clutches 27, 27 'include friction plates 27a, 27'a which are rotationally fixed to a differential case (drive input section) 18, and side gears (drive output section).
Friction disc 27 fixed in rotation direction at 21, 21 '
b, 27'b, and pressure rings 28, 28 'and reaction plates 29, 29' are arranged on both end surfaces in the axial direction.

The pressure rings 28, 28 'are provided in a fitted state on the pinion mate shaft 19 as a member for receiving a clutch engaging force, and the fitting portion has a rectangular cross section as shown in FIG. Square grooves 28a, 28 'with respect to the end 19a
The structure is such that the thrust force due to the rotation difference is not generated unlike the conventional torque proportional type differential limiting mechanism by fitting by a.

The hydraulic piston 33 moves in the axial direction (to the right in the drawing) by the hydraulic pressure supplied to the hydraulic port 35, and the multi-plate friction clutch
27, 27 'are engaged according to the hydraulic pressure level, and one multi-plate friction clutch 27 has a fastening force of push rod 32 →
Spacer 31 → Thrust bearing 30 → Reaction plate 29
And is fastened by the pressure ring 28 as a reaction force receiver.
The fastening reaction force from is used as the fastening force for fastening.

As shown in FIG. 4, the hydraulic pressure generating device 12 is an external device that generates hydraulic pressure to be a 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 (valve actuator) having a valve solenoid 45.

The pump motor 41 is a motor that is activated / deactivated according to a motor signal (m) from the control unit 13, and may be running or may be performing differential limiting. When the motor signal (m) is supplied when the motor is energized, the motor signal (m) is supplied when the motor is not energized when no differential limitation is required such as when the vehicle is stopped.

The electromagnetic proportional pressure reducing valve 46 supplies the hydraulic oil having the pump pressure supplied from the hydraulic pump 40 through the pump pressure oil passage 42 to the control current signal (i) from the control unit 13
A valve actuator that controls the control oil pressure P proportional to the magnitude of the current value i and sends the control oil pressure P from the control pressure oil passage 44 to the oil pressure port 35 and the oil chamber 34.
Is output to the valve solenoid 45 of the electromagnetic proportional pressure reducing valve 46.

The control oil pressure P and the differential limiting torque T are in the relationship of T∝P · μ · n · rA n; number of clutches r; average clutch radius A; pressure receiving area. Proportional to.

The control unit 13 uses an in-vehicle microcomputer, and has an input circuit 131, a RAM (random access memory) 132, and a ROM (read only memory).
133, CPU (Central Processing Unit) 13
4. A clock circuit 135 and an output circuit 136 are provided.

As the input sensor 14, a gear position sensor 141 that detects a gear position (shift position) of the transmission and outputs a gear position signal (s) is provided.

The input circuit 131 is a circuit for exchanging the input signal (s) from the gear position sensor 141 with a signal that can be processed by a CPU.

The RAM 132 is a writable and readable memory, and is used to write input signals from the sensors 141 and 142 and to write information during calculation in the CPU 134.

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

The CPU 134 is a device that performs arithmetic processing on various input information in accordance with predetermined processing conditions.

The clock circuit 135 is a circuit for setting the arithmetic processing time in the CPU 134.

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

In the ROM 133 of the control unit 13, as shown in FIG. 5, a control current value i ^* for generating a differential limiting torque T different depending on the gear position is set as a control current value map. Then, at 1st speed and reverse (gear position signals S ₁ , R), small current value, at 2nd speed and 3rd speed (gear position signals S ₂ , S ₃ ), large current value, at 4th speed (gear position signal) signal
S ₄ ) is set to a medium current value.

Next, the operation of the embodiment will be described.

First, the operation of the sixth embodiment will be described with reference to the operation flow of the differential limiting control.
This will be described with reference to the flowchart shown in the figure.

(A) At first speed or reverse At the first speed position or reverse position, which is often used for garage parking, etc., step 200 → step 201 → step 20
The flow is 2 → step 203. In step 203, the control current signal (i) with a small current value is output.

Step 200 is a step of reading the gear position signal (s) from the gear position sensor 141, step 201 is a step of determining which gear position the gear position signal (s) is, and step 202 is a step of determining. This is a step of retrieving a current value from the control current value map based on the gear position (reverse position or first speed position) determined in step 201.

(B) In 2nd or 3rd speed Step 200 → in 2nd or 3rd position, which is often used for passing sports such as overtaking
The flow is step 201 → step 204 → step 205, and in step 205, the control current signal (i) with a large current value is output.

(C) 4th speed At the 4th speed position (overdrive position), which is often used when driving at high speeds, etc., step 200 → step 201
→ Step 206 → Step 207 is followed, and in step 207, the control current signal (i) with the medium current value is output.

As described above, in the differential limiting control device of the embodiment,
At the time of speed or reverse, the control current signal (i) with a small current value is output to reduce the differential limiting torque, so that the garage entry operation can be easily performed.

Further, in the 2nd speed or the 3rd speed, since the control current signal (i) with a large current value is output to increase the differential limiting torque, the differential limiting torque becomes constant even when the accelerator is rapidly operated during turning, for example. It is possible to keep turning and tack-in etc. are suppressed and turn the target course, and at the time of overtaking, sufficient driving force is secured for both the left and right wheels, enabling smooth overtaking.

Further, at the time of the fourth speed, the control current signal (i) based on the medium current value is output to generate an appropriate differential limiting torque, so that traveling with excellent high-speed straight traveling stability can be performed.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, in the example, the same differential limiting torque is obtained at the reverse position and the first speed position and the same differential limiting torque is obtained at the second speed position and the third speed position among the gear positions. Alternatively, different differential limiting torques may be obtained at each gear position.

Further, in the embodiment, an example in which a control current value map with one control current value is set for each gear position has been shown, but a plurality of control current value maps with different control current values are set. In advance, the optimum map may be automatically selected by a manual changeover switch or an input signal from a road surface friction coefficient sensor or the like.

Further, in the embodiment, the electromagnetic proportional pressure reducing valve is shown as the actuator, but an example in which an opening / closing electromagnetic valve or the like is used and a hydraulic pressure control is performed by using a control signal as a duty signal may be performed.

(Effects of the Invention) As described above, in the vehicle differential limiting control device of the present invention, different differential limiting torques are generated depending on the gear position, and the differential limiting torque is set to the gear position. When the gear is in the low speed and the reverse, the control means is set to a value that is lower than that in the middle and high speeds.Therefore, the small turning performance is secured when the gear is in the low speed and the reverse, and the gear is in the middle. This has the effect of achieving both turning stability, driving performance, and high-speed straight running stability at high speeds.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a differential limiting control device for a vehicle of the present invention, FIG. 2 is a sectional view showing a differential device incorporating a differential control means of a device of an embodiment of the present invention, and FIG. 2 is a view from the Z direction, FIG. 4 is a diagram showing a hydraulic pressure generator and a control device of the embodiment device, and FIG. 5 is a control current value for each gear position stored in advance in the control unit of the embodiment device. FIG. 6 is a control map shown, and FIG. 6 is a flow chart showing a flow of differential limiting control operation of the embodiment apparatus. 1 ... drive left wheel 2 ... drive right wheel 3 ... differential means 4 ... differential limiting means 5 ... input sensor 501 ... gear position sensor 6 ... control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatsugu Owada 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) References: 60-70426 (JP, U) 22431 (JP, U)

Claims (1)

[Claims] Claim: What is claimed is: 1. A differential means for distributing and transmitting the engine driving force to the left and right drive wheels while allowing differential, and a differential input means and a drive output section of the differential means. A differential limiting unit that generates a differential limiting torque, an input sensor that detects a vehicle state, and a control unit that outputs a control signal that increases or decreases the differential limiting torque based on an input signal from the input sensor are provided. In a vehicle differential limiting control device, the input sensor includes a gear position sensor that detects a gear position of a transmission, and the control means generates a differential limiting torque that varies depending on a gear position, A differential limiting control device for a vehicle, wherein the torque is set to a lower value when the gear position is in a low speed stage and a reverse stage as compared to when the gear position is in a middle / high speed stage.