JPH0626937B2 - Vehicle drive system clutch control device - Google Patents

Description

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. The present invention relates to a vehicle drive system clutch control device that variably controls a force distribution ratio.

(Prior Art) Conventionally, as a device for controlling the clutch engagement force of a limited slip differential clutch, which is an example of a drive system clutch, for example, a device described in Japanese Utility Model Laid-Open No. 58-177642 is known. ing.

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

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

Conventionally, as a device for controlling a differential locking device (differential limiting device), for example, a device described in JP-A-60-143135 is known.

This conventional device is intended to activate the differential locking device to limit the differential between the left and right wheels when the accelerator pedal is operated so as to cause the wheel to spin.

(Problems to be Solved by the Invention) However, in the former conventional example, since the differential limiting amount is controlled only by the rotational speed of the differential case, that is, only the vehicle speed, A high differential limiting amount can be obtained at high speeds while traveling, and traveling safety can be secured, but the limited differential amount is said to be insufficient during sports driving where sudden acceleration or rapid start is performed at low or medium speeds. There was a problem.

Further, in the latter conventional example, since the limited differential amount is controlled only by the operation that may cause wheel spin, that is, the acceleration operation by the accelerator pedal, It is preferable that the differential limit amount increases in response to the accelerator pedal operation during sports driving where a sudden start is intentionally performed, but during normal running, the differential limiting amount changes too sensitively and the steering wheel is changed. There was a problem that the steering holding force suddenly changed and the vehicle behavior changed too much.

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

The solution means of the present invention will be described with reference to the conceptual diagram of the claims shown in FIG. 1. A power split device 3 for distributing and transmitting an engine driving force to front and rear or left and right drive wheels 1 and 2, and a drive input of the power split device 3. Between the drive unit and the drive output unit, the transmission system torque means 4 capable of changing the transmission torque according to the magnitude of the clutch engagement force, and the increase / decrease control of the clutch engagement force based on the input signal from the detection means 5. In the vehicle drive system clutch control device including the clutch control means 6 for performing, the vehicle speed detection means 501 and the acceleration operation detection means 502 are included as the detection means 5.
A control characteristic mode including at least a first control characteristic mode having a high vehicle speed dependency and a second control characteristic mode having a high acceleration operation dependency, and one mode from these control characteristic modes. The mode selection means 7 for selecting is provided.

(Operation) Therefore, in the vehicle drive system clutch control device of the present invention,
By adopting the above-mentioned means, for example, during normal traveling, by selecting the first control characteristic mode having a high vehicle speed dependency by the mode selecting means, clutch engagement force control that is less affected by the acceleration operation is performed, and steering stability is improved. It is possible to maintain driving stability. Further, during sports driving, by selecting the second control characteristic mode having high dependency on acceleration operation, the response to the acceleration operation is sensitive and it is possible to travel while suppressing wheel slip and the like.

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

First, the configuration of the first embodiment will be described.

As shown in FIGS. 2 to 4, the embodiment apparatus includes 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 detecting means 14, and a select switch (mode selecting means) 15, and the respective configurations 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 that distributes and transmits the distribution.

The differential device 10 is housed in a housing 16 attached to a vehicle body by a stud bolt 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 'are provided.

The differential case 18 includes a housing 16
On the other hand, it is rotatably supported by tapered roller bearings 22 and 22 '.

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

The left gear side drive shaft 25 and the right wheel side drive shaft 2 which are drive output shafts are provided on the side gears 21 and 21 '.
6 are provided for each.

The multi-disc friction clutch means 11 is provided between the drive input portion and the drive output portion of the differential device 10 and is a means for applying a clutch engaging force by an external hydraulic pressure to generate a differential limiting torque.

The multi-plate friction clutch means 11 is housed in the housing 16 and the differential case 18, and comprises multi-plate friction clutches 27, 27 ', pressure rings 28, 28', reaction plates 29, 29 ', thrust bearing 30. , 30 ', spacers 31, 31', push rod 32, hydraulic piston 33, oil chamber 34, and hydraulic port 35.

The multi-plate friction clutches 27, 27 'are fixed in the rotational direction by friction plates 27a, 27'a fixed in the differential case (drive input section) 18 in the rotational direction, and by side gears (drive output sections) 21, 21'. The friction disks 27b and 27'b are provided, and the pressure rings 28 and 28 'are provided on both end surfaces in the axial direction.
And reaction plates 29, 29 'are arranged.

The pressure rings 28, 28 'are provided in a fitted state on the pinion mate shaft 19 as a member for receiving a clutch fastening force, and the fitting portion has a rectangular cross section as shown in FIG. The end portion 19a is fitted in the square grooves 28a and 28'a so that the thrust force due to the rotation difference is not generated like the conventional torque proportional differential limiting means.

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 to engage both multi-plate friction clutches 27, 27 'in accordance with the hydraulic level. In the clutch 27, the fastening force is transmitted to the push rod 32 → the spacer 31 → the thrust bearing 30 → the reaction plate 29, and the pressure ring 2 is transmitted.
8 is fastened as a reaction force receiver, and the other multi-plate friction clutch 27 'is fastened by the fastening reaction force from the housing 16 as a fastening force.

As shown in FIG. 4, the hydraulic pressure generator 12 is an external device that generates a hydraulic pressure that is a clutch engagement force, and is a hydraulic pump 4
0, a pump motor 41, a pump pressure oil passage 42, a drain oil passage 43, a control pressure oil passage 44, and a solenoid proportional pressure reducing valve 4 having a valve solenoid 45 as a valve actuator.
6 is provided.

The pump motor 41 is a motor that is activated / deactivated according to a motor signal (m) from the control unit 13, and is capable of performing differential limitation or performing differential limitation during traveling. 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 has a control current value i ^* of hydraulic oil having a pump pressure supplied from the hydraulic pump 40 via the pump pressure oil passage 42 in response to a control current signal (i) from the control unit 13. The control current signal (i) is a valve actuator that pressure-controls the control oil pressure P proportional to the pressure (FIG. 5) 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. It is output to the valve solenoid 45 of the electromagnetic proportional pressure reducing valve 46.

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

The control unit 13 uses an in-vehicle microcomputer, and has an input circuit 131, a RAM (random access memory) 132, a ROM (read only memory) 133, a CPU (central processing unit) 134, a clock. The circuit 135 and the output circuit 136 are provided.

In addition, as an 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 select switch 15 is provided as mode selection means.
Is provided.

The input circuit 131 is a circuit for inputting the input signals (v) and (a) from the input means 14 and the switch signal (s) from the select switch 15.

The RAM 132 is a writable and readable memory in which input signals from the sensors 141 and 142 are written and information is written during calculation in the CPU 134.

The ROM 133 is a read-only memory,
Information necessary for the arithmetic processing in the CPU 134 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 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) corresponding to the vehicle speed V.

The accelerator opening sensor 142 is a sensor that detects the degree of depression on 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 assel opening sensor 142
Is used as a sensor for searching the target clutch pressure P 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. .

The select switch 15 is a mode selecting means provided at a position where it can be manually operated from the driver's seat in the vehicle interior,
As shown in Fig. 4, Free mode, which cancels the differential limitation,
Town mode (first control characteristic mode) used during normal driving, mode selection is automatically performed according to the driving state
It has an Auto mode, a sport mode (second control characteristic mode) used during sports driving, and a Lock mode for continuously obtaining the maximum differential limiting amount.

The select switch 15 outputs a switch signal (s) corresponding to the selected mode position to the input circuit 131 of the control unit 13.

Further, as shown in FIG. 7, the ROM 133 of the control unit 13 has an accelerator opening A of 0% to 10%.
Even if it changes to 0%, the accelerator opening gain K remains constant (K
= K ₁ ), that is, the first control characteristic map M ₁ that is highly dependent on the vehicle speed V is set, and as shown in FIG. 8, the accelerator opening A is 0%, 25%, Fifty
%, 100%, the accelerator opening gain K becomes
It changes to K ₁ , K ₃ , K ₄ , and K ₅ according to the accelerator opening A, that is, the second degree of dependence on the accelerator opening A is high.
The control characteristic map M ₂ is set.

However, both the control characteristic maps M ₁ and M ₂ are both the vehicle speed V ₁
To increase the above high vehicle speed range straight running stability at (vehicle speed 80 km / h) or more, increasing the accelerator opening gain K ₂ of high vehicle speed range than the accelerator opening gain K ₁ for low vehicle speed region, small accelerator opening However, it has a progressive characteristic that the clutch pressure P increases at high vehicle speeds.

Further, the selection criterion for the both control characteristic maps M ₁ and M ₂ when the select switch 15 is selected in the Auto mode is that the accelerator opening change rate, which is the time change rate of the accelerator opening A, is set. Degree of change ^* or less (
≦ ^* ), or whether it exceeds (> ^* ). When ≦ ^* , the first control characteristic map M ₁ is selected, and when> ^* , the second control characteristic map M ₂ is selected. .

That is, the first control characteristic map M ₁ is selected when the town mode is selected by the select switch 15 or when the Auto mode is selected and ≦ ^* , and the second control characteristic map M ₁ is selected.
Use the select switch 15 to select the control characteristic map M _2.
This is done when> mode is selected or when Auto mode is selected and> ^* .

Next, the operation of the first embodiment will be described.

First, the operation flow of the differential limiting control of the first embodiment will be described with reference to the flow chart shown in FIG.

(B) When the Free mode is selected When the low speed large steering etc.
When the mode is selected, step 200 → step 201 → step 202 → step 203 → step 2
In step 204, which is an output step, the control current signal (i) of i ^* = 0 for setting the clutch pressure P to zero is output.

Step 200 is a vehicle speed V based on the vehicle speed signal (v) from the vehicle speed sensor 141, an accelerator opening A based on the accelerator opening signal (a) from the accelerator opening sensor 142, and a switch signal (s) from the select switch 15. Is the reading step.

Step 201 is a calculation step for calculating the accelerator opening change rate based on the current accelerator opening An read in step 200 and the previously read accelerator opening An _-1 .

The formula for the accelerator opening change rate is Is.

Step 202 is a mode judging step for judging the mode selected by the switch signal (s) read in the step 200.

Step 203 is a clutch pressure designating step for designating the clutch pressure P to P = 0.

In this way, when the Free mode is selected by the select switch 15, it becomes an ordinary conventional differential in which no differential limitation is made at all, and the steering force is increased by the differential limiting torque T at the time of large speed low speed steering such as garage parking. It can be resolved.

(B) When the town mode is selected During normal driving and when the select switch 15 is selected in the town mode, step 200 → step 20
1 → step 202 → step 205 → step 206
→ The operation flow is step 204, and the target clutch pressure P retrieved in step 204 which is the output step
The control current signal (i) is output according to the control current value i ^* for which = P ₀ is obtained.

Step 205 is a characteristic selection step for selecting the control characteristic M _A according to the accelerator opening A from the first control characteristic map M ₁ , and step 206 is based on the control characteristic M _A and the vehicle speed V selected in step 205. Target clutch pressure P
_This is a search step for searching for ₀ .

As described above, when the town mode is selected by the select switch 15, the accelerator opening gain K is constant (K =
K ₁ ), which is the clutch pressure control based on the first control characteristic map M ₁ which is highly dependent on the vehicle speed V, and there is no abrupt change in the clutch pressure P due to the acceleration operation, and the higher the vehicle speed V, the more As the accelerator pedal opening A is larger, a larger differential limit amount is obtained and the control reaches normal running.

(C) When Auto mode is selected When the select switch 15 is selected to be in Auto mode, step 200 → step 201 → step 202
→ step 207 → step 205 (or step 2
08) → step 206 → step 204, and in step 204 which is an output step, the control current value i at which the retrieved target clutch pressure P = P ₀ is obtained
^The control current signal (i) by ^* is output.

The step 207 selects the first control characteristic map M ₁ if the calculated accelerator opening change rate and set the accelerator opening change rate ^* and compared to a ≦ ^* in the step 201, the if> ^* 2 is a determination step of selecting a control characteristic map.

As described above, when the Auto mode is selected by the select switch 15, the first control characteristic map that is highly dependent on the vehicle speed V depending on the magnitude of the accelerator opening change rate that is the time change rate of the accelerator opening A. M ₁ or accelerator opening A
Second control characteristic map M highly dependent on (acceleration operation)
Any one of the _two is automatically selected, and the control characteristic mode suitable for the traveling state is automatically selected without performing the switching operation by the select switch 15.

(D) When sport mode is selected Select sport switch 15 when sport driving is being performed while the accelerator pedal is being suddenly pressed or released.
When the mode is selected, step 200 → step 201 → step 202 → step 208 → step 2
The operation flow is 06 → step 204, and in step 204, which is the output step, the control current signal (i) is output according to the control current value i ^* that obtains the searched target clutch pressure P = P ₀ .

Incidentally, step 208 is a characteristic selection step of selecting the control characteristic M _A according to the accelerator opening A from the second control characteristic map M ₂ .

As described above, when the sport mode is selected with the select switch 15, the clutch pressure control is based on the second control characteristic map M _{2 in} which the accelerator opening gain K is large, that is, the degree of dependence of the accelerator opening A is high. , The clutch pressure P increases sensitively to the acceleration operation, and the control is suitable for sports driving.

(E) When the Lock mode is selected When traveling on muddy ground, bad roads, snowy roads, etc., and when the select switch 15 is selected in the Lock mode, step 200 → step 201 → step 202 → step 2
The flow of operation is 09 → step 204, and in step 204 which is the output step, the control current signal (i) with the current value that maximizes the clutch pressure P is output.

Incidentally, step 209 is a clutch pressure specifying step for specifying the clutch pressure P as P = full.

As described above, when the Lock mode is selected by the select switch 15, the vehicle always travels with the maximum differential limit being secured, and it is possible to escape from the muddy ground or to go straight on a bad road or a snowy road. Increase.

As described above, in the vehicle limited differential clutch control system of the first embodiment, the control unit 13 has the first control characteristic map M _{1 in} which the vehicle speed V is highly dependent.
The second control characteristic map M in which the degree of dependence between the accelerator opening A and the accelerator opening degree A is high.
₂ and are set, and these control characteristic maps M ₁ ,
Since the configuration is provided with the select switch 15 having the town mode and the sport mode in which any one of M ₂ can be selected, the clutch engagement force that is less affected by the acceleration operation is selected by selecting the first control characteristic map M ₁ during normal traveling. It is possible to maintain steering stability and running stability by controlling, and during sports driving, the response to acceleration operation is sensitive and it will run while suppressing wheel slip etc. The differential limiting amount can be controlled.

Further, in the first embodiment, the mode of the select switch 15 includes the Auto mode, and when this Auto mode is selected, the first control characteristic map M ₁ or the second control characteristic map M ₂ is automatically set according to the accelerator opening change rate. Since the selection is made, the control characteristic mode suitable for the traveling state is selected even if the driver does not switch the select switch 15.

Further, in the first embodiment, the modes of the select switch 15 include the Free mode and the Lock mode, the differential limitation is released in the Free mode, and the differential limitation amount is maximized in the Lock mode. It is also possible to cope with a traveling state that does not require differential limitation or a traveling state that always requires differential limitation.

Next, a second embodiment shown in FIG. 10 will be described.

In the second embodiment, the select switch 15 is used in the first embodiment.
On the other hand, in the Auto mode, the control characteristic map M ₁ or M ₂ is selected depending on whether the accelerator opening change rate is larger or smaller than the set accelerator opening change rate ^* as a boundary condition. , The accelerator opening change rate is 0 <
When ≤ ₀ ( ₀ < ^* ), the first control characteristic map M ₁ is selected, when> ₁ ( ₁ > ^* ), the second control characteristic map M ₂ is selected, and when ₀ <≤ ₁ , the following is selected. In this example, the target clutch pressure P = P _Auto is calculated by the calculation formula shown in FIG.

The formula for P _Auto is _Where P _town is the clutch pressure obtained from the first control characteristic map M ₁ , the accelerator opening A and the vehicle speed V, and P _town
sport is the clutch pressure obtained from the second control characteristic map M ₂ , the accelerator opening A and the vehicle speed V.

Therefore, when the select switch 15 is selected in the Auto mode and the accelerator opening change rate is ₀ <≦ ₁ , step 200 → step 201 → step 202
The flow proceeds from step 210 to step 211 to step 204. When the Auto mode is selected, _one control characteristic map M ₁ or M ₂ is selected until the other is selected. Transition period ( ₀ <≤ ₁ )
In the case of ( ₁₎ , the intermediate control characteristic of both control characteristic maps M ₁ and M ₂ causes the clutch pressure P to change continuously and steplessly while shifting to the other control characteristic map M ₁ or M _2. Therefore, it is possible to eliminate a sudden change in clutch pressure while running in Auto mode.

The configuration and other control contents of the second embodiment are the same as those of the first embodiment, and the description thereof will be omitted.

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 embodiment, the example of the limited differential clutch control device is shown, but it is also applicable to a transfer clutch that changes the driving force distribution ratio of a transfer device that distributes the driving force of a four-wheel drive vehicle to the front and rear wheels. In this case, the same effect as in the case of the limited slip differential clutch can be obtained.

Further, although the hydraulically actuated clutch is shown in the embodiment, other clutch means such as an electromagnetic clutch may be used.

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 drive system clutch control device of the present invention, the clutch control means includes the first control characteristic mode having a high vehicle speed dependence and the acceleration operation dependence. And a control characteristic mode including at least a high second control characteristic mode, and 1 from these control characteristic modes.
Since the mode selection means for selecting one of the two modes is provided, it is possible to control the drive system clutch according to the traveling state such as normal traveling or sports traveling and the control characteristic according to the driver's preference by selecting the control characteristic mode. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a claim showing a drive system clutch control device for a vehicle of the present invention, FIG. 2 is a sectional view showing a differential device incorporating a differential limiting device of a first embodiment device of the present invention, and FIG. 2 is a view from the direction of Z in FIG. 2, FIG. 4 is a view showing a hydraulic pressure generating device and a control device of the embodiment device, FIG. 5 is a characteristic diagram of control hydraulic pressure (clutch pressure) with respect to a control current value, and FIG. The differential limiting torque characteristic diagram for the control oil pressure P, FIG. 7 is the first control characteristic map diagram which is stored in the control unit in advance, and FIG. 8 is the second control characteristic map which is stored in the control unit in advance.
FIG. 9 is a control characteristic map diagram, FIG. 9 is a flowchart showing a flow of differential limiting control operation of the first embodiment device, and FIG. 10 is a flowchart diagram showing a flow of differential limiting control operation of the second embodiment device. . 1, 2 ... Drive wheels 3 ... Power split device 4 ... Drive system clutch means 5 ... Detection means 501 ... Vehicle speed detection means 502 ... Acceleration operation detection means 6 ... Clutch control means 7 ... Mode selection means

Claims (2)

[Claims] 1. A power split device for distributing and transmitting an engine driving force to front and rear or left and right drive wheels, and a power split device provided between a drive input part and a drive output part of the power split device, the power split device having a clutch engaging force depending on a magnitude thereof. A vehicle drive system clutch control device comprising: a drive system clutch means capable of changing a transmission torque; and a clutch control means for increasing / decreasing a clutch engaging force based on an input signal from the detection means. As a control, the vehicle speed detection means and the acceleration operation detection means are included, and the clutch control means includes at least a first control characteristic mode having a high vehicle speed dependence and a second control characteristic mode having a high acceleration operation dependence. A drive system clutch control device for a vehicle, characterized in that a mode selecting means is provided for setting a characteristic mode and selecting one of these control characteristic modes. . 2. The mode selecting means selects the first control characteristic mode when the time change rate of the input signal from the acceleration operation detecting means is small, and selects the second control characteristic mode when the time change rate is large. The drive system clutch control device for a vehicle according to claim 1, wherein the device has an automatic mode selecting function.