JPH051166B2 - - Google Patents

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 the amount of differential differential between left and right wheels and drive the front and rear wheels. The present invention relates to a drive system clutch control device for a vehicle equipped with a shift pattern switching type transmission that variably controls the force distribution ratio.

(Prior Art) Conventionally, as a device for controlling the clutch engagement force of a differential limiting clutch, which is an example of a drive system clutch, a device such as that described in Japanese Utility Model Application Publication No. 177642/1983 has been known. ing.

This conventional device is provided with a centrifugal clutch that fixes at least either the pinion gear or the side gear to the differential case when the differential case rotates at high speed.

Note that this centrifugal clutch is a differential limiting clutch in which the clutch engagement force increases as the rotational speed of the differential case increases.

Furthermore, as a conventional device for controlling a differential locking device (differential limiting means), for example, a device as described in Japanese Patent Application Laid-open No. 143135/1983 is known.

This conventional device operates a differential locking device to limit the differential movement between the left and right wheels when the accelerator pedal is operated in a manner that may cause the wheels to spin.

(Problem to be Solved by the Invention) However, in the former conventional example, the differential limiting amount is controlled only depending on the rotation speed of the differential case, that is, the vehicle speed. Therefore, during normal driving and at high speeds, a high differential limit amount can be obtained and driving stability can be ensured. There was a problem in that the differential limit amount was insufficient during sports driving involving acceleration and sudden starts.

In addition, in the latter conventional example, the differential limiting amount was controlled solely by operations that could cause wheelspin, that is, acceleration operations using the accelerator pedal, so sudden acceleration and During sports driving where a sudden start is performed intentionally, it is preferable to respond sensitively to the accelerator pedal operation and increase the differential limit amount, but during normal driving with the transmission's shifting characteristics switched to the standard pattern, the differential limit amount increases. The limit amount changes too sensitively,
There were problems in that the steering wheel holding force suddenly changed and the vehicle behavior changed too much.

(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. Input signals are received from drive system clutch means 4, which is provided between the drive output section and the drive output section, and is capable of changing the transmitted torque depending on the magnitude of the clutch engagement force, and from detection means 5, which detects the traveling state or driving state of the vehicle. Clutch control means 6 for controlling the increase/decrease of clutch engagement force based on
In the drive system clutch control device for a vehicle with a shift pattern switching type transmission, the clutch control means 6 has a first control characteristic in which the clutch engagement force increases or decreases in a small range in response to a change in the input signal; A control characteristic that includes at least a second control characteristic that has a large increase/decrease range in the clutch engagement force relative to
Now you can select one control characteristic.

In addition, here, what is a shift pattern switching type transmission?
Refers to automatic transmissions that can change the shift schedule to switch between sport and standard patterns, and manual transmissions that are equipped with an auxiliary transmission and can switch between power mode and economy mode.

(Function) Therefore, in the drive system clutch control device for a vehicle with a shift pattern switching type transmission of the present invention, by using the above-mentioned means, for example, a shift pattern switching type transmission can be provided with normal shifting characteristics. When driving in the shift pattern mode, the first control characteristic, which has a small increase or decrease in the clutch engagement force in response to changes in the input signal, is selected, resulting in clutch engagement force control that is less affected by acceleration operations, etc., which improves steering stability and driving performance. Stability can be maintained. In addition, when driving in sports with the shift pattern switching type transmission switched to a shift pattern mode that provides torque-oriented shifting characteristics, the second control characteristic, which has a large increase/decrease range in clutch engagement force in response to changes in the input signal, is selected and accelerates. Sensitive to operations, etc.
It is possible to drive while suppressing wheel slip etc.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
In describing this embodiment, we will discuss a differential limiting clutch for an automobile equipped with an automatic transmission with shift pattern switching and a multi-disc friction clutch means (differential limiting clutch means) operated by external hydraulic pressure. Take a control device as an example.

First, the configuration of the embodiment will be explained.

As shown in FIGS. 2 to 4, the embodiment device has the following features:
It is equipped with a differential device (power split device) 10, a multi-plate friction clutch means (drive system clutch means) 11, a hydraulic pressure generator 12, a control unit (clutch control means) 13, a detection means 14, and a shift pattern select switch 15. 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 rotational speed difference in a driving state where a rotational speed difference occurs between the left and right wheels;
This device has a driving force distribution function that equally distributes and transmits the engine driving force to the left and right drive wheels.

This differential device 10 is housed in a housing 16 that is attached to the vehicle body with stud bolts 15, and includes a ring gear 17, a differential case 18, and a pinion mate shaft 1.
9, differential pinion 20, side gear 21, 21'
It is equipped with

The differential case 18 has a tapered roller bearing 22,
It is rotatably supported by 22'.

The ring gear 17 is fixed to a differential case 18 and is connected to the propeller shaft 2.
3, and rotational driving force is input from this drive pinion 24.

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

The multi-plate friction clutch means 11 is connected to the differential gear 1.
0 between the drive input section and the drive output section,
This is a means for generating differential limiting torque by applying clutch engagement force using external hydraulic pressure.

This multi-plate friction clutch means 11 is housed within a housing 16 and a differential case 18, and includes multi-plate friction clutches 27, 2.
7' Pressure ring 28, 28', reaction plate 29, 29', thrust bearing 30, 3
0', spacer 31, 31', push rod 3
2, hydraulic piston 33, oil chamber 34, hydraulic port 3
5.

The multi-plate friction clutches 27, 27' include friction plates 27a, 2 fixed to the differential case (drive input section) 18 in the rotational direction.
7'a and side gear (drive output part) 21, 2
1' and friction disks 27b, 27'b fixed in the rotational direction, and pressure rings 28, 28' and reaction plates 29, 29' are arranged on both end faces in the axial direction. There is.

The pressure rings 28, 28' are provided in a fitted state on the pinion mate shaft 19 as members receiving the clutch fastening force, and the fitting portion has a rectangular cross section as shown in FIG. It is fitted to the shaft end 19a through square grooves 28a, 28'a, and has a structure in which no thrust force is generated due to a rotational difference, unlike the conventional torque proportional differential limiting means.

The hydraulic piston 33 moves in the axial direction (rightward in the drawing) by hydraulic pressure supplied to the hydraulic port 35,
Both multi-plate friction clutches 27, 27' are engaged in accordance with the oil pressure level, and in one multi-disc friction clutch 27, the engagement force is transmitted from the push rod 32 to the spacer 31 to the thrust bearing 30 to the reaction plate 29. , are fastened using the pressure ring 28 as a reaction force receiver, and the other multi-plate friction clutch 27' is fastened using the fastening reaction force from the housing 16 as a fastening force.

As shown in FIG. 4, the hydraulic pressure generating device 12 is an external device that generates hydraulic pressure that becomes the clutch engagement force.
A hydraulic pump 40, a pump motor 41, a pump pressure oil line 42, a drain oil line 43, a control pressure oil line 44, an electromagnetic proportional pressure reducing valve 46 having a valve solenoid 45, a return oil line 47, an oil temperature sensor 48, and a valve solenoid 49. Switching solenoid valve with 5
0, an orifice 51, and a reserve tank 52.

The electromagnetic proportional pressure reducing valve 46 is connected to the hydraulic pump 4
The hydraulic oil at the pump pressure supplied from 0 through the pump pressure oil path 42 is pressure controlled to a control oil pressure P proportional to the magnitude of the control current value i ^* by the control current signal i from the control unit 13. (5th
) is a valve actuator that sends control oil pressure P from a control pressure oil path 44 to a hydraulic port 35 and an oil chamber 34, and the control current signal i is a valve actuator that sends control oil pressure P from a control pressure oil passage 44 to a hydraulic port 35 and an oil chamber 34.
It is output to the valve solenoid 45 of No. 6.

The control oil pressure (clutch pressure) P and the differential limiting torque T have the following relationship: T∝P・μ・n・r・A n; number of clutches r; clutch average radius A; pressure receiving area, as shown in Figure 6. As shown in the torque characteristic, the differential limiting torque T is proportional to the control oil pressure P.

The switching solenoid valve 50 is connected to the oil chamber 3.
A return oil passage 4 from a return port 53 opened to 4
When the oil temperature signal t from the oil temperature sensor 48 is inputted to the oil passage opening/closing means provided in the middle of the oil passage 7, a solenoid activation signal d is sent from the control unit 13 when a signal indicating a low oil temperature is inputted, which is less than the set oil temperature _T0 . is output, the return oil passage 47 is opened, and the hydraulic oil is circulated.

Therefore, by circulating the hydraulic oil when the oil temperature is low, even if the viscosity of the hydraulic oil becomes high at low oil temperatures, the hydraulic oil circulation can prevent a decrease in hydraulic response. Further, by providing an orifice 51 in the return oil path, the oil pressure can be increased while circulating the hydraulic oil.

The control unit 13 uses an in-vehicle microcomputer, and includes an input circuit 131,
RAM (random access memory) 132,
ROM (read only memory) 133,
CPU (Central Processing Unit) 1
34, a clock circuit 135, and an output circuit 136.

As input means to the control unit 13, a vehicle speed sensor (vehicle speed detection means) 141 and an accelerator opening sensor (acceleration operation detection means) 142 are provided as detection means, and a shift pattern select switch is provided as shift pattern selection means. 15 are provided.

The input circuit 131 is a circuit that receives input signals v and a from the input means 14 and a switch signal s from the shift pattern select switch 15.

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

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-only from the CPU 13 as necessary.
It is read from 4.

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 vehicle speed sensor 141 is a sensor that detects the vehicle speed V of the vehicle and outputs a vehicle speed signal v according to the vehicle speed V.

The accelerator opening sensor 142 is a sensor that detects the degree of depression of the accelerator pedal and outputs an accelerator opening signal a corresponding to the accelerator opening (also referred to as throttle opening).

The vehicle speed sensor 141 and the accelerator opening sensor 142 determine the target clutch from the first control characteristic map M ₁ (FIG. 7) or the second control characteristic map M ₂ (FIG. 8) preset in the control unit 13. It is used as a sensor to search for pressure P.

The shift pattern select switch 15 is
It is a shift pattern selection means provided in a position that can be manually operated from the driver's seat in the vehicle interior, and as shown in Figure 4, it is a standard shift pattern selection means used during normal driving.
It has an Auto mode that automatically selects a mode depending on the driving condition, and a Power mode that is used during sports driving.

Furthermore, this shift pattern select switch 15
From there, a switch signal s corresponding to the selected mode position is outputted to the input circuit 131 of the control unit 13.

In addition, the ROM of the control unit 13
133, as shown in FIG. 7, even if the accelerator opening A changes from 0% to 100%, the accelerator opening gain K is constant (K=K ₁ ), that is,
First control characteristic map M ₁ that is highly dependent on vehicle speed V
is set, and as shown in Figure 8,
When the accelerator opening degree A changes from 0%, 25%, 50%, and 100%, the accelerator opening gain K changes from K ₁ to K ₃ to K ₄ to K ₅ according to the accelerator opening degree A, i.e. , a second control characteristic map _M2 that is highly dependent on the accelerator opening degree A is set.

However, both control characteristic maps M ₁ and M ₂ are based on the accelerator opening gain K 1 in the low vehicle speed range in order to improve straight-line stability in the high vehicle speed range ₍ vehicle speed 80 km/h) where the vehicle speed is V ₁ or higher. The accelerator opening gain _K2 is increased in the high vehicle speed range, and the clutch pressure P increases as the vehicle speed increases even with a small accelerator opening, creating a progressive characteristic.

Further, the shift pattern select switch 1
5 is selected as Auto mode, the selection criteria for both control characteristic maps M ₁ and M ₂ is the accelerator opening change rate, which is the time change rate of the accelerator opening A.
A〓 is the set accelerator opening change rate A〓 ^* Is it less than or equal to (A〓≦A〓
^* ), or exceeds (A〓＞A〓 ^* ). When A〓≦A〓 ^* , the first control characteristic map is selected.
M ₁ is selected, and when A〓>A〓 ^*, the second control characteristic map M ₂ is selected.

In other words, the first control characteristic map _M1 is selected by the shift pattern select switch 15.
The second control characteristic map _M2 is selected when the power mode is selected with the shift pattern select switch ¹⁵ . or when Auto mode is selected and A〓＞A〓
It is done at the time of ^* .

Next, the operation of the embodiment will be explained.

First, the operational flow of the differential limiting control of the embodiment will be explained in the ninth section.
This will be explained using the flowchart shown in the figure.

(b) When standard mode is selected During normal driving, when shift pattern select switch 15 is selected to standard mode, step 200 → step 201 → step 202
The operation flow is as follows: -> step 203 -> step 204 -> step 205, and in step 205, which is an output step, a control current signal i based on a control current value i ^* that provides the searched target clutch pressure P ₀ is output.

Note that step 200 is a step of reading the vehicle speed V based on the vehicle speed signal v from the vehicle speed sensor 141, the accelerator opening A based on the accelerator opening signal a from the accelerator opening sensor 142, and the switch signal s from the select switch 15. be.

Step 201 is a calculation step that calculates the accelerator opening change rate A〓 based on the current accelerator opening An read in step 200 and the accelerator opening A _o-1 read last time.

The calculation formula for the accelerator opening change rate A is A = An-A _o-1 /t t; control cycle time.

Step 202 is a mode determination step in which the selected mode is determined based on the switch signal s read in step 200.

Step 203 is a characteristic selection step that selects a control characteristic M A corresponding to the accelerator opening degree A from the first control characteristic map M ₁ , and step 204 is a characteristic selection step that selects a control characteristic M _A corresponding to the accelerator opening degree A from the first control characteristic map M 1 .
This is a search step in which the target clutch pressure _P0 is searched based on the control characteristic M _A selected in step 1 and the vehicle speed V.

In this way, when the standard mode is selected with the shift pattern select switch 15, the accelerator opening gain K is constant (K=K ₁ ),
First control characteristic map highly dependent on vehicle speed V
Clutch pressure control is based on _M1 , and there is no sudden change in clutch pressure P due to acceleration operation, and the higher the vehicle speed V and the greater the accelerator opening A, the greater the differential limit amount can be obtained. The control is suitable for driving.

(b) When Auto mode is selected When the select switch 15 is set to Auto mode, the operation flow is step 200 → step 201 → step 202 → step 206 → step 203 (or step 207) → step 204 → step 205. and step 205 which is the output step
Then, a control current signal i based on a control current value i ^* that provides the searched target clutch pressure P ₀ is output.

Note that step 206 calculates the accelerator opening change rate A〓 calculated in step 201 and the set accelerator opening change rate A〓 ^*
This is a judgment step in which the first control characteristic map _M1 is selected if A〓≦A〓 ^* , and the second control characteristic map is selected if A〓>A〓 ^* .

In this way, when the shift pattern select switch 15 selects the Auto mode, the accelerator opening change rate which is the time change rate of the accelerator opening A
Depending on the magnitude of A〓, either the first control characteristic map _M1 is highly dependent on the vehicle speed V, or the second control characteristic map is highly dependent on the accelerator opening A (acceleration operation).
_M2 is automatically selected, and a control characteristic suitable for the driving condition is automatically selected without performing a switching operation using the shift pattern select switch 15.

(c) When power mode is selected When you are driving in a sporty manner while suddenly pressing or releasing the accelerator pedal, and the shift pattern select switch 15 is set to power mode, step 200 → step 201 → step
The operation flow is 202→step 207→step 204→step 205, and in step 205, which is an output step, a control current signal i based on a control current value i ^* that provides the searched target clutch pressure P ₀ is output.

Incidentally, step 207 is a characteristic selection step in which a control characteristic M A corresponding to the accelerator opening degree _A is selected from the second control characteristic map _M2 .

In this way, when the power mode is selected with the shift pattern select switch 15, the clutch pressure based on the second control characteristic map _M2 has a large accelerator opening gain K, that is, it is highly dependent on the accelerator opening A. The clutch pressure P increases in response to acceleration operations, resulting in control suitable for sports driving.

As explained above, in the automotive differential limiting clutch control device of the embodiment, the control unit 13 is provided with a first control characteristic map M ₁ in which the accelerator opening gain K is highly dependent on the vehicle speed V and is constant.
and a second control characteristic map _M2 in which the accelerator opening degree gain K increases with acceleration operation,
Since either of these control characteristic maps M ₁ or M ₂ is configured to be selected by the shift pattern select switch 15, during normal driving with the standard mode selected, the first control characteristic map
By selecting _M1 , the clutch engagement force is controlled with less influence from acceleration operations, maintaining steering stability and driving stability.In addition, when selecting power mode for sport driving, the responsiveness to acceleration operations is reduced. This makes it possible to drive while suppressing wheel slip, etc., and to control the differential limiting amount using a control characteristic mode suitable for the driving conditions.

Further, in the embodiment, the mode of the shift pattern select switch 15 includes Auto mode,
When this Auto mode is selected, the accelerator opening change rate
Since the selection between the first control characteristic map _M1 and the second control characteristic map _M2 is automatically made by A〓, even if the driver does not switch the shift pattern select switch 15, Control characteristics appropriate for the conditions are selected.

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 without departing from the gist of the present invention. included.

For example, although the embodiment shows an example of a differential limiting clutch control device, it can also be applied to a transfer clutch that changes the drive force distribution ratio of a transfer device that distributes the drive force of a four-wheel drive vehicle to the front and rear wheels. , in this case as well, the same effect as in the case of a differential limiting clutch can be obtained.

In addition, although an example of an automatic transmission with shift pattern switching was shown in the embodiment, a vehicle has a manual transmission that has an auxiliary transmission and can switch between multiple transmission characteristics such as power mode and economy mode by switching the auxiliary transmission. It can also be applied to In this case, switching of the shift pattern is not limited to manual switching, but may also be switched automatically depending on the driving conditions, and can be easily carried out by inputting a switching signal to the control unit.

Further, although a hydraulically actuated clutch is shown in the embodiment, other clutch means such as an electromagnetic clutch may 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 using a control signal as a duty signal may also be used.

(Effects of the Invention) As explained above, in the drive system clutch control device for a vehicle with a shift pattern switching type transmission according to the present invention, the clutch control means is configured to adjust the range of increase/decrease in the clutch engagement force in response to changes in the input signal. small first
and a second control characteristic that has a large increase/decrease range in the clutch engagement force with respect to input signal changes, and from these control characteristics, the shift characteristics of the shift pattern switching type transmission are determined. Since one mode suitable for the transmission is selected, it is possible to control the drive system clutch with control characteristics that match the speed change characteristics of the transmission.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a claim showing a drive system clutch control device for a vehicle with a shift pattern switching type transmission according to the present invention, and Fig. 2 is a cross-sectional view showing a differential device incorporating differential limiting means of an embodiment of the device of the present invention. 3 is a view in the Z direction of FIG. 2, FIG. 4 is a diagram showing the hydraulic pressure generating device and control device of the embodiment device, and FIG. 5 is a characteristic diagram of control hydraulic pressure (clutch pressure) with respect to control current value. , Fig. 6 is a differential limit torque characteristic diagram with respect to the control oil pressure P, Fig. 7 is a map of the first control characteristic stored in advance in the control unit, and Fig. 8 is a map diagram of the second control characteristic stored in advance in the control unit. The characteristic map diagram and FIG. 9 are flowcharts showing the flow of the differential limiting control operation of the embodiment device. 1, 2... Drive wheel, 3... Power split device, 4...
...Drive system clutch means, 5...Detection means, 6...
Clutch control means, 7...Shift pattern switching type transmission.

Claims (1)

[Scope of 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 power split device that is provided between a drive input section and a drive output section of the power split device, drive system clutch means capable of changing transmission torque; and clutch control means controlling increase/decrease of clutch engagement force based on an input signal from a detection means for detecting running or driving conditions of the vehicle. In a drive system clutch control device for a vehicle with a shift pattern switching type transmission, the clutch control means has a first control characteristic in which the clutch engagement force increases or decreases in a small range in response to a change in the input signal, and a first control characteristic in which the clutch engagement force increases or decreases in response to a change in the input signal. A second control characteristic having a large width, and a control characteristic including at least a second control characteristic having a large width are set, and one control characteristic matching the shift characteristic of the shift pattern switching type transmission is selected from these control characteristics. A drive system clutch control device for a vehicle equipped with a shift pattern switching type transmission.