JP2623651B2 - Drive system clutch control device for vehicles - Google Patents

Description

The present invention is used as a drive force distribution control device for a four-wheel drive vehicle or a differential limit control device for a differential mechanism between left and right drive shafts and between front and rear drive shafts. The present invention relates to a vehicle drive system clutch control device.

2. Description of the Related Art Conventionally, as a driving force distribution control device for a four-wheel drive vehicle, for example, a device described in Japanese Patent Application Laid-Open No. 61-154737 is known.

In this conventional device, the clutch torque is adjusted according to the front and rear wheel rotational speed difference ΔN in order to achieve wheel spin prevention at the time of sudden acceleration or start, one wheel lock prevention at the time of sudden braking, slip prevention at the time of traveling on a low u road, and the like. That is, as the front-rear wheel rotational speed difference ΔN increases, the clutch torque increases to change the front-rear driving force distribution to the four-wheel drive direction, and the clutch torque decreases as the front-rear wheel rotational speed difference ΔN decreases. Thus, the control content for changing the front-rear drive force distribution in the two-wheel drive direction is used.

(Problems to be Solved by the Invention) However, in such a conventional driving force distribution control device, the clutch torque control is a ΔN feedback control system. When the control gain is large, the control system generates hunting, the fluctuation of torque and wheel rotation becomes large, noise is generated, or the vehicle vibrates greatly back and forth, and jerky vibration is continuously generated. Had the problem of getting lost.

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

A solution to the present invention will be described with reference to the conceptual diagram of the claims shown in FIG. 1. A friction clutch a is provided at a position where engine driving force can be distributed to front and rear wheels or left and right wheels, and is engaged by an external clutch torque. A drive system for a vehicle, comprising: a clutch torque control means b provided outside the friction clutch a and configured to control increase and decrease of the clutch torque so as to obtain a command clutch torque obtained based on predetermined input information and control contents. In the clutch control device, the clutch torque control unit b includes a hunting detection unit c that predicts and detects hunting of clutch torque from a change state of a command clutch torque to the friction clutch a, and that hunting is predicted by the hunting detection unit c. If a situation is detected, the amount of change in the command clutch torque per unit time is reduced. Characterized in that it has a clutch torque regulation portion d that.

(Operation) When the clutch torque of the friction clutch a is controlled to increase or decrease by the clutch torque control means b, the hunting detection unit c detects a situation in which hunting of the clutch torque is predicted from the command clutch torque to the friction clutch a. In this case, the amount of change in the command clutch torque per unit time is restricted by the clutch torque restriction unit d.

Therefore, since hunting is detected from the command clutch torque to the friction clutch a, it is possible to easily and accurately detect a situation in which hunting of the clutch torque is predicted. Therefore, it is possible to prevent the noise and the rattling vibration caused by the control system hunting from actually occurring in the prediction stage of the command clutch torque beforehand.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In describing this embodiment, a driving force distribution control device for a four-wheel drive vehicle will be described as an example.

 First, the configuration will be described.

As shown in FIG. 2, the drive system of the four-wheel drive vehicle to which the driving force distribution control device of the embodiment is applied includes an engine 1, a transmission 2, a transfer input shaft 3, a transfer clutch device C, a rear propeller shaft 4, The vehicle includes a rear differential 5, rear wheels 6, a transfer output shaft 7, a front propeller shaft 8, a front differential 9, and a front wheel 10. The engine driving force that has passed through the transmission 2 is directly transmitted to the rear wheels, and is transmitted to the front wheels 10. Is transmitted through a transfer clutch device C provided between the transfer input / output shafts 3 and 7.

Outside the transfer clutch device C, a hydraulic control device 20 is provided as clutch torque control means for generating a control hydraulic pressure Pc serving as a clutch torque based on predetermined input information and control contents.

The hydraulic control device 20 includes a motor 22 that is driven or stopped by a relief switch 21, a hydraulic pump 24 that is operated by the motor 22 and draws up from a reservoir tank 23, and a pump discharge pressure (primary pressure) from the hydraulic pump 24. An accumulator 26 stored through a check valve 25 and a line pressure (secondary pressure) from the accumulator 26 are controlled by a command control current i ^* from a control unit 27 to a predetermined control hydraulic pressure.
An electromagnetic proportional pressure valve 28 that adjusts to Pc is provided, and is supplied to a control hydraulic port 30 through a control hydraulic pipe 29.

The control unit 27 has an electronic control circuit configuration and includes a front wheel rotation speed sensor 31, a rear wheel rotation speed sensor 32, a control constant setting unit 33, and the like as information input sensors. Usually, for example, as shown in FIG. As described above, the command clutch torque T corresponding to the front and rear wheel rotation speed difference ΔN is obtained according to the torque characteristic having the torque increasing / decreasing gradient different depending on the control constant k. That is, the optimum front and rear wheel driving force distribution ratio is determined according to the running state. The obtained control is performed. However, hunting of the clutch torque is predicted and detected from the change state of the command clutch torque T, and if a situation in which the occurrence of hunting is predicted is detected, the command clutch torque T is filtered. Control that suppresses torque hunting to a level that does not pose a practical problem by reducing responsiveness is performed before actual hunting occurs. It is.

As shown in FIG. 4, the transfer clutch device C includes a multi-plate friction clutch 60 that is engaged by a pressing mechanism 40 that is operated by a control hydraulic pressure Pc from an external hydraulic control device 20,
A lubricating oil 15 for cooling the clutch provided in the transfer input shaft 3 and in the transfer case 11 and the case cover 12.
To remove the lubricating oil 15 inside the multi-plate friction clutch 60.
And a lubrication pump 70 that guides the

The pressing mechanism 40 of the multi-plate friction clutch 60 includes a cylinder block 41, a piston chamber 42, a piston 43, a piston rod 44, a swing plate 45, a swing pin 46, a fixed pressure plate 47, a bearing 48, and a rotary pressure plate.
49, a pressure block 50, and a litter spring 51 are provided.

The multi-plate friction clutch 60 includes a clutch drum 61 that is spline-coupled to the transfer input shaft 3, a drive plate 62 that is spline-fitted to the clutch drum 61,
A driven plate 63 sandwiched between the drive plates 62, and the driven plate 63 is spline-fitted,
A clutch hub 65 rotatably supported by a need bearing 64 with respect to the transfer input shaft 3 is provided.

The clutch hub 65 is provided with a first sprocket 66
The drive torque is transmitted to the transfer output shaft 7 via the chain 67 and the second sprocket 68.

The lubricating pump 70 is of a trochoid plow type provided in a pump housing 71 and a pump cover 72 at the inlet of the transfer input shaft 3, and has a suction port 73.
Communicates with a suction tube 75 having a suction port 74, and its discharge port 76 is connected to a radial oil passage 77, an axial oil passage 78, a radial oil passage 79, and a clutch hub formed in the transfer input shaft 3. The lubricating oil 15 for cooling the clutch in the transfer case 11 is drawn into the oil holes 80 and 81 formed in the transfer case 11, the lubricating oil 15 is guided to the multi-plate friction clutch 60, and discharged from the oil hole 82.

The transfer output shaft 7 and the chain 67 to the front wheel 10 provided offset from the transfer input shaft 3 are immersed in the clutch cooling lubricating oil 15 stored in the lower portion of the transfer case 11, Lubrication pump
70 inlets 74 are arranged.

In FIG. 2, 90 is a joint flange, 91, 92, 93 are seals, and 94, 95, 96, 97, 98 are bearings.

 Next, the operation will be described.

First, the flow of the clutch torque control processing operation performed by the control unit 27 of the embodiment will be described with reference to the flowchart of FIG.

In step 101, the command clutch torque T _XX corresponding to the front and rear wheel rotational speed difference ΔN is obtained, i.e., the optimal front-rear wheel driving force distribution ratio normal control obtained is performed according to the running state.

The command clutch torque T _XX is the difference between the front and rear wheel rotation speed Δ
It is obtained from N by the following equation.

T _XX = f (ΔN) (FIG. 3) ΔN = | Nr−Nf | In step 102, it is determined whether or not the torque high peak value T _H1 is set.

If T _H1 = 0, hunting has not occurred in the normal control state until then, and if T _H1 > 0, it indicates that hunting has already been predicted and the hunting prevention logic has been started. If YES is determined in step 102, the process jumps to step 109.

In steps 103 and 104, it is determined whether or not the torque waveform has a high peak. That is, the current command clutch torque T _XX , the command clutch torque one control cycle before
When the relationship between T _XO , the command clutch torque T _X-1 two control cycles ago is T _XO > T _X-1 and T _XO > T _XX , a high peak is set.

In step 105, whether the peak value T _XO detected in the step 103 and 104 exceeds the set value A ₂ is determined.

In step 106, if it exceeds the set value A ₂ at the step 105, the peak value T _XO is set as H Peak 1 (T _H1).

If it is determined in Steps 103 to 105 that it is not the peak 1, the command clutch torques T _XX and T _XO at present and one control cycle before are rewritten at Step 107, respectively, and are calculated by the normal control at Step 108. The command control current i ^* based on the value _TXX is output.

In step 109, time measurement is started by the counter HCNT.

In step 110, it is determined whether the value of the counter HCNT has exceeded the set value _AO .

Then, in the case of Hont ≦ A _O, the process proceeds to subsequent step 111 by determining that it is a hunting state, HCNT> For A _O, is determined not to be hunting state, the end of the logic step 115 to step 117 Or step 118
Proceed to.

In step 111, it is determined whether or not the torque low peak value _TH1 has been set.

If T _L1 > 0, it is determined that the minimum value has already been detected, and the routine jumps to step 119.

In steps 112 and 113, it is determined whether or not the torque waveform has a low peak. That is, the relationship between the command clutch torques T _XX , T _XO , and T _X-1 has a low peak when T _XO <T _X-1 and T _XO <T _XX .

In step 114, the peak value in steps 112 and 113
T _XO is set as L peak 1.

In steps 119 to 122, steps 103 to
H peak 2 (T _H2 ), which is the second torque high peak value, is set by the same processing as in step 106.

In step 123, the hunting amplitude ΔT and the period Δt
Thus, a permissible change width of the command torque (low-pass filter value) ΔT _LPASS is obtained by the following calculation.

T _HH = max (T _H1 , T _H2 ) ΔT = T _HH −T _L1 Δt = HCNT ΔT _LPASS = f (ΔT, Δt) = ΔT / Δt × aa; arbitrary value (for example, 1/2) The real time of Δt is (HCNT × control cycle).

In step 124, the hunting amplitude ΔT is set to the set value A ₁
It is determined whether or not:

In the case of [Delta] T ≦ A _1, because it is generating hunting levels that do not know the passenger proceeds to step 129.

In steps 125 and 126, the low-pass filter value ∇T _LPASS
To update.

However, in step 125, the current low-pass filter value ΔT _LPASS is _smaller than the previous low-pass filter value ΔT _LPASS.
Is not updated if is large. In step 126, the low-pass filter value ΔT _LPASS is calculated by the same formula as in step 123.

Here, the low-pass filter value ΔT _LPASS gradually decreases _because the ΔT decreases.
_{Becomes LPASS} and regulations are tightened.

In step 127, HCNT, each data T _H1, T _L1 is updated.

In step 128, the hunting prevention control is being performed and H
It is determined whether or not _TH2, which is the peak value 2, is set.

In step 129, on whether a low-pass filter value T.DELTA. _LPASS, heretofore whether in hunting prevention control is judged.

If ΔT _LPASS > 0, the hunting prevention control is continued _while the value of ΔT _LPASS remains unchanged, and if ΔT _LPASS =, the hunting prevention control ends, and the _routine proceeds to step 118 for clearing each data.

Step 115 to Step 117 is a relaxation treatment step of the filter, when the low-pass filter value [Delta] T _LPASS has become a set value A ₃ greater than in step 115,
Proceed to step 118 to end the hunting prevention control.

In step 115, if the low-pass filter value [Delta] T _LPASS set value A ₃ is smaller than the low-pass filter value [Delta] T
_{Increase LPASS} gradually.

ΔT _LPASS = ΔT _LPASS × _ββ ; arbitrary value (for example, 2) In step 117, the counter value HCNT is cleared.

Steps 130 to 136 correspond to the command clutch torque T
_This is a process for regulating _XX by a low-pass filter.

In step 130, the magnitude of the current command clutch torque T _XX value and the command clutch torque T _XO one control cycle before is determined, and in step 131 or step 132, 1
The amplitude ΔT ₁ during the control cycle is calculated. And step
In step 133 or step 134, the magnitude of the amplitude ΔT ₁ and the current low-pass filter value ΔT _LPASS are compared, and the magnitude Δ
If T ₁ is large, the command clutch torque by the low-pass filter value [Delta] T _LPASS in step 135 or step 136
A calculation regulating T _XX is performed.

Next, the clutch torque control action in the embodiment will be described focusing on the hunting prevention control action.

(A) Start condition of hunting prevention control The hunting prevention control monitors a change state of the command clutch torque T, and is started when the command clutch torque T indicates a change state in which the occurrence of hunting is actually predicted. Become.

That is, the following three conditions are set as hunting occurrence conditions, and when all of these conditions are satisfied, hunting prevention control is started (see FIG. 6).

When torque high peak value T _H1, T _H2 exceeds a set value A ₂ (step 105, step 121).

Time from the first torque high peak value T _H1 to the next torque high peak value T _H2 , that is, the torque change period Δt
(= HCNT) is less than the set value A _O (step 11)
0).

Is the difference between the maximum value T _HH and minimum value T _L1 of the torque amplitude Δ
When T exceeds the set value A ₁ (step 124).

(B) During hunting prevention control When the above three conditions are satisfied, first, the low pass filter value ΔT _LPASS set in step 123 is used to _obtain
In the processes of steps 130 to 136, the command clutch torque T is regulated by the low-pass filter (see B to B in FIG. 7).
C).

When the command clutch torque T satisfies the above three conditions despite this restriction, the low pass filter value ΔT _LPASS updated in
In the processing from 130 to step 136, the command clutch torque T is regulated by the low-pass filter (C to D in FIG. 7).

Further, as long as the above three conditions are satisfied, the command clutch torque T is regulated by the low-pass filter in the processing of steps 130 to 136 by the low-pass filter value ΔT _LPASS in step 125 or step 126 (see FIG. 7). D
~ E).

Therefore, the hunting of the clutch torque is predicted and detected from the change state of the command clutch torque T, and if the situation where the occurrence of the hunting is predicted is detected first, the command clutch torque T is immediately filtered from the next time to respond. The control is performed to reduce the torque hunting to a level that does not cause a practical problem by lowering the performance, so that the generation of noise and rattling vibration due to the hunting of the control system is predicted at the command clutch torque T prediction stage. Can be prevented.

(C) Termination condition of hunting prevention control In the hunting prevention control, when any one of the above three control start conditions is not satisfied, the filter is held or relaxed as follows. And the above conditions are no longer satisfied, and
When the condition of 115 is not satisfied, or when the above condition is no longer satisfied and the condition of step 129 is no longer satisfied, the process proceeds to step 118 which is an end step,
The hunting prevention control ends.

If the torque high peak value T _H2 equal to or less than the set value A ₂ is until the torque high peak value T _H1 less than or equal to the specified value A _2, without updating the low-pass filter value [Delta] T _LPASS, step 130 to The restriction process in step 136 is performed, and the filter is relaxed (case 121 in FIG. 8).

If the torque change period Δt (= HCNT) exceeds the set value A _O, unless the low-pass filter value [Delta] T _LPASS is smaller than the set value A ₃ are low-pass filtered value [Delta] T _LPASS is gradually increased in step 116, the filter Is gradually alleviated, and the control ends (110 in FIG. 8).

Is the difference between the maximum value T _HH and minimum value T _L1 of the torque amplitude Δ
When T is equal to or less than the set value A _1, as long as the low-pass filter value [Delta] T _LPASS exceeds the 0 without updating the low-pass filter value [Delta] T _LPASS, regulations step 130 to step 136 is repeated The filter is retained (case 124 in FIG. 8).

The control is terminated only when the low-pass filter value ΔT _LPASS = 0.

Therefore, when the hunting prevention control is started,
The hunting prevention control ends after the filter is relaxed or held, and after the hunting prevention control ends, the occurrence of an undesired situation such as the reoccurrence of hunting is avoided immediately, and the noise and rattling vibration caused by hunting are reduced. It is effectively prevented from occurring continuously.

Although the embodiment has been described with reference to the drawings, the specific configuration and control contents are not limited to this embodiment.

For example, in the embodiment, an example in which the present invention is applied to a driving force distribution control device of a four-wheel drive vehicle is described.

(Effects of the Invention) As described above, in the vehicle drive system clutch control device of the present invention, the clutch torque control means determines whether or not hunting of the clutch torque has occurred based on the change in the command clutch torque to the friction clutch. A hunting detection unit for predicting and detecting, and a hunting detection unit detects a situation in which hunting is predicted. In addition to accurately detecting the situation where hunting of clutch torque is predicted,
The effect is obtained that it is possible to prevent the occurrence of noise or rattling vibration accompanying the control system hunting in the prediction stage with the command clutch torque.

[Brief description of the drawings]

FIG. 1 is a conceptual view of a vehicle drive system clutch control device according to the present invention, and FIG. 2 is a diagram showing a drive system and a control system of a four-wheel drive vehicle to which a drive force distribution control device of the embodiment is applied. FIG. 3 is a command clutch torque characteristic diagram of the embodiment device, and FIG.
FIG. 5 is a cross-sectional view showing a transfer clutch device used in the embodiment device, FIG. 5 is a flowchart showing a flow of a clutch torque control operation including hunting prevention control in a control unit of the embodiment, and FIG. FIG. 7 is a time chart for explaining a control start condition, FIG. 7 is a time chart of a command clutch torque according to an example of hunting prevention control, and FIG. 8 is a time indicating that the hunting prevention control ends after the filter is relaxed or held. It is a chart figure. a: friction clutch b: clutch torque control means c: hunting detection unit d: clutch torque regulation unit

Claims (1)

(57) [Claims] A friction clutch which is provided at a position where engine driving force can be distributed to front and rear wheels or left and right wheels, and is engaged by an external clutch torque; A vehicle drive system clutch control device comprising: clutch torque control means for controlling increase / decrease of the clutch torque so as to obtain a command clutch torque obtained based on the control content. The clutch torque control means includes: A hunting detection unit that predicts and detects hunting of clutch torque from a change situation of the command clutch torque to the hunting detection unit, and when a hunting detection condition is detected by the hunting detection unit, the amount of change in the command clutch torque per unit time is reduced. A vehicle drive system clutch having a clutch torque regulating portion for regulating Pitch control device.