KR101629346B1

KR101629346B1 - Method for controlling clutch unit

Info

Publication number: KR101629346B1
Application number: KR1020090062994A
Authority: KR
Inventors: 마틴 키에스너-하이덴
Original assignee: 마그나 파워트레인 게엠베하 운트 코 카게
Priority date: 2008-07-10
Filing date: 2009-07-10
Publication date: 2016-06-10
Also published as: KR20100007793A; DE102008032477A1; DE102008032477B4

Abstract

The present invention relates to a method of controlling a clutch unit for a vehicle power train, comprising a wet friction clutch for controllable torque transmission from an input element of the clutch unit to an output element, Oil, and an actuator for driving the friction clutch. The deterioration degree of the oil is calculated for control of the clutch unit, the characteristic curve of the friction clutch is adapted based on the calculated degree of deterioration, and the clutch unit is controlled according to the characteristic curve using the actuator.

Clutch unit, friction clutch, actuator, oil degradation, characteristic curve

Description

[0001] METHOD FOR CONTROLLING CLUTCH UNIT [0002]

The present invention relates to a method of controlling a clutch unit for a vehicle power train wherein the clutch unit comprises at least a wet friction clutch for transferring controllable torque from an input element of the clutch unit to an output element, And an actuator for driving the friction clutch. The friction clutch includes a first clutch disc and a second clutch disc arranged alternately.

Such a clutch unit is used, for example, in a transfer case of a vehicle equipped with a front wheel drive for controllably transmitting drive torque to the primary and / or secondary axle of the vehicle. In the case of a so-called 'torque-on-demand' transfer case, the wheels of the first axis are always driven while the variable parts of the drive torque are selectively transmitted to the wheels of the second axis using the above- . The transfer case may also be designed as a controllable center differential in which the clutch unit is assigned to a differential lock to set the distribution of the drive torque in the vehicle longitudinal direction. The above-described type of clutch unit can also be used in a torque transmitting device that allows a part of the drive torque to be transmitted to the rear axle in a vehicle with a normally driven front axle, in which case the unit is arranged in the front axle differential or the rear axle differential . These different applications and configurations are known from US 7,111,716 B2.

The clutch unit of the type referred to in the introduction can also act in the vehicle transverse direction, for example for the differential lock of the axle differential or in the torque transmission of an axle differential (so-called torque vectoring). In all of the above cases, the clutch unit can couple the rotary input element (e.g., input shaft) and the rotary output element (e.g., output shaft) frictionally to each other, particularly for the transmission of drive torque. Alternatively, the clutch unit may be configured as a brake with a stationary input element or a stationary output element, in particular for transmitting braking torque.

In the application of the clutch unit described above, the clutch unit is disposed behind the main transmission of the power train (i.e., behind the manual or automatic transmission or CVT transmission) with respect to the direction of power flow. The clutch torque, that is, the torque transmitted from the friction clutch, is generally adjusted variably according to each running situation. That is, the torque to be transmitted from the clutch unit fluctuates in accordance with the traveling dynamics requirements, which may depend on, for example, a running situation or a peripheral influence (e.g., a slippery road surface causing slippage of the drive wheels). This is often required not only for the engagement control of the friction clutch, but also for a slower drive with precisely adjusted clutch torque.

Therefore, the friction clutch is usually formed as a wet multi-plate clutch in the case of the above-described application. Generally, the friction clutch is incorporated in a housing containing oil for cooling and lubricating the friction parts. For example, an oil sump is provided on the bottom of the housing from which the oil pump always carries the oil and falls on the friction surface during clutch operation. The oil returns from the friction surface back to the oil sump.

The clutch unit also includes an actuator for driving the friction clutch. The actuator often includes an electric motor fixed to the housing of the clutch unit and is used to move the clutch discs to a predetermined engagement position in response to the required torque to be transferred between the input and output elements of the clutch unit.

A clutch unit of the type referred to in the introduction and a method for correcting such a clutch unit are known from WO 2003/025422 Al (corresponding to US 7,032,733 B2), the contents of which are incorporated into the disclosure of the present application. As described precisely in WO 2003/025422 A1, direct torque control need not necessarily be provided (with the measured actual clutch torque as a control variable) for adjustment of the specific required clutch torque, and by appropriate correction of the clutch unit , The control of the friction clutch can be implemented through the position control of the actuator. That is, for example, the rotation angle of the electric motor or other actuator position variable is used as a control variable and adjusted to a value corresponding to the required clutch torque to adjust the required torque to be transmitted. To this end, the clutch torque / actuator position dependence is calculated empirically and stored as a characteristic curve, for example in the form of a table (lookup table, LUT) or a function (i.e., a calculation rule). Depending on the dependence, the corresponding setpoints of the actuator's associated position variables (e.g., rotation angle) are determined and adjusted for the particular torque demand.

Wear or deterioration occurs in the oil present in the clutch unit during driving of the friction clutch, for example, due to accumulation of wear particles. Owing to the wear of the oil, the friction value at the clutch disc varies over time, and thus the actually delivered torque, which depends on the friction value of the clutch disc at a particular actuator position, also fluctuates. This variation can not be accounted for through the static allocation between the torque demand and the actuator position described above. Therefore, an undesirable deviation may occur between the designated clutch torque (set value) and the actually transmitted clutch torque (actual value). Higher oil deterioration may result in significant fluctuations in friction values in such a way that excessive torque results in reduced ride comfort, stresses in the powertrain, or other deleterious loads on transmission components.

An object of the present invention is to reduce the deviation between the set value and the actual value of the clutch torque to increase the accuracy of the clutch control. In addition, an excessively high load of the clutch unit parts must be prevented.

This problem is solved by a clutch unit control method having the features of claim 1, and in particular through the following steps.

Calculating a loss output of the clutch unit to calculate an oil deterioration degree;

- adapting a friction clutch characteristic curve describing the dependence of the clutch torque on the actuator control variable, on the basis of the calculated degree of deterioration; And

Controlling the clutch unit according to the characteristic curve using an actuator.

In accordance with the present invention, a dynamic adaptation of the clutch control is implemented based on the degree of deterioration of the oil, which is a key influencing variable associated with the correlation between the actuator control variable and the transmitted torque. This can be effectively achieved by calculating the loss output assigned to the clutch unit and adaptively adapting the friction clutch characteristic curve stored in the non-volatile memory. Through this type of adaptation, the deviation of the clutch characteristic curve and the standard behavior due to wear is compensated, thereby increasing the adjustment accuracy of the clutch unit. The correlation between the oil degradation and the torque deviation to be compensated can be calculated or calculated in an empirical manner, and can exist, for example, in the form of a look-up table. The adaptation of the characteristic curve allows the clutch control to be calibrated quickly and reliably. The adaptation of the characteristic curve can be performed particularly every time the vehicle drive is started.

Preferably by calculating the loss output of the clutch disc or the drag torque loss output of the clutch unit or the shear action loss output of the transmission of the clutch unit or by calculating several of the above described loss outputs, do. The clutch disc loss output is an important indicator of oil degradation since it has a direct correlation with the friction occurring at the disc surface. The drag torque loss output is related to efficiency loss due to oil acceptance by the components of the clutch unit, which also correlates with oil degradation in the clutch unit. Fluid transport by an oil pump can also be considered for drag torque loss output.

The above-described shear action loss output is related to oil deterioration caused by the shearing process, particularly in the transmission of the clutch unit. The transmission may be a part for converting the torque transmitted from the friction clutch. The transmission is used to transmit torque or convert the torque numerically, in particular, to an output shaft arranged in parallel or angularly with respect to the input shaft. For this purpose, a power train may be provided, for example a front wheel lock system or a chain drive system which couples the friction clutch with the output elements of the clutch unit. The oil sump oil may be used for lubrication of the powertrain.

Since the above-described loss outputs are important influential variables for oil degradation in the clutch unit, they can be preferably used for estimation of oil degradation.

Preferably, the clutch torque is multiplied by the rotational speed difference between the input element and the output element of the clutch unit to calculate the loss output of the clutch disc. The relevant number of revolutions can be easily detected by suitable sensors and used according to the standard for various purposes of vehicle control. The clutch torque may be a required torque (set point) or an actual transmitted torque (actual value) that can be measured or calculated. The clutch torque is correlated with the compression force acting on the clutch disc. The difference in the number of revolutions between the input element and the output element indicates a slip occurring in the friction clutch. Thus friction loss of the clutch disc can be deduced through the product of the compression force and the slip.

Preferably, the product of the clutch torque and the rotational speed difference is multiplied by a weighting factor, which is selected according to the clutch torque, the rotational speed difference or the product of the clutch torque and the rotational speed difference. It has been found that oil degradation is not only dependent on the clutch disk loss, i.e. the total energy absorbed through the clutch disc, but also on the energy consumption behavior over time. For example, less wear and hence less oil degradation may result if the low loss output lasts over a relatively longer period of time than if the high loss output lasts over a short period of time. This situation can be easily taken into account by multiplying by the weighting factor. The weighting factor can be calculated, for example, by an empirical method.

In order to calculate the drag torque loss output, the drag torque value calculated by an empirical method can be multiplied by the number of rotations of the input element or the output element of the clutch unit. The drag torque value does not necessarily have to be a constant variable, but it may also vary with the number of revolutions. The drag torque value can be called from the stored look-up table. Thus, the energy loss due to the drag torque can be estimated.

In order to calculate the shear acting loss output, the clutch torque can be multiplied by the efficiency value calculated by an empirical method and the number of rotations of the input element or output element of the clutch unit. The clutch torque may be a set value or an actual value. The efficiency value may depend on the number of rotations of the input element and may be called, for example, from a previously stored lookup table. In this way, the accuracy of the calculation of the wear rate can be further increased.

Preferably, in order to calculate the loss output of the clutch unit, a plurality, especially all three, of the three loss outputs described above are calculated and added to each other. In this way, all of the major contributors to the wear of the clutch unit can be considered. Before the addition, the addend may be multiplied by a weighting factor, respectively, in order to weight the individual contribution factors relative to each other corresponding to their degradation.

Preferably, a time integral value for the loss output is generated during operation of the clutch unit. From this loss output, which can be easily calculated, a loss event with a final direct correlation with oil degradation can be deduced.

The calculated clutch unit loss date is preferably stored in the nonvolatile memory at the time of vehicle stop so that it is used as a starting value for continuously calculating the oil deterioration when the vehicle drive is restarted. That is, the total loss is extrapolated continuously because the oil degradation caused by the total loss is irreversible. That is, the oil deterioration proceeds continuously, for example, at the time of stopping the vehicle. The reset of the calculated loss day is only carried out at oil change.

Preferably, in order to control the clutch unit based on the characteristic curve described above, the set value of the associated actuator control variable is calculated as a function of the set value of the clutch torque, and the set value of the calculated actuator control variable is adjusted, The actual value of the control variable is detected and compared with the set value. The actuator control variable is generally easier to approach than the clutch torque itself in the measurement technical detection, so that the control relating to the set value and the actual value of the selected actuator control variable can be implemented more easily. The actuator control variable may be, for example, the actuator position (in particular the angle of rotation) or hydraulic pressure.

According to one preferred embodiment, the slope and / or offset of the characteristic curve is changed for adaptation of the characteristic curve described above. For the adaptation of the characteristic curve, the tilt correction value and the offset correction value can be determined on the basis of the calculated oil deterioration value, in which the set value of the clutch torque is multiplied by the tilt correction value in order to calculate the changed set value of the clutch torque At this time, the provisional set value of the actuator control variable is calculated as a function of the changed set value of the clutch torque according to the characteristic curve, and the offset correction value is added to the temporary set value of the actuator control variable to calculate the set value of the actuator control variable. In this process, the stored characteristic curve itself remains unchanged because only the two parameters assigned to the characteristic curve are updated. In this way, a complete rewrite of the characteristic curve involving the corresponding calculation cost and memory cost is prevented. The tilt correction value and the offset correction value may be calculated by an empirical method and stored in a simple look-up table.

According to yet another embodiment, the wear of the clutch disc is calculated, and the adaptation of the friction clutch characteristic curve is further implemented based on the calculated clutch disc wear. That is, the wear may reduce the thickness of the clutch disc and cause hardening of the clutch disc material. Such material hardening can also cause an increase in friction value. To optimize the promotional accuracy of the clutch unit, the effect can be considered during the characteristic curve adaptation process.

Preferably, the wear of the clutch disc is calculated based on the variation in the thickness of the clutch disc during driving of the clutch unit. Since hardening of the disk material is generally accompanied by a reduction in disk thickness, a comparison of the thickness can be used to simply find a measure of the increase in friction due to hardening and disk wear.

Preferably, the thickness of the clutch disc is calculated based on the actuator position value calculated in association with the predetermined correction position in the correction process of the clutch unit. This enables highly reliable detection of the disc thickness.

The invention also relates to a torque transmitting device comprising a clutch unit and a control device, the clutch unit comprising at least a wet friction clutch for transferring controllable torque from an input element to an output element, And an actuator for driving the friction clutch, wherein the control device calculates the loss output of the clutch unit to calculate the degree of deterioration of the oil, and based on the calculated degree of deterioration, , And is designed to control the clutch unit according to the characteristic curve using an actuator.

The clutch unit and torque transmission device according to the present invention can be used in different configurations to deliver torque along the vehicle powertrain as described above. The present invention will now be described by way of example only with reference to the "torque on demand" transfer case with reference to the figures.

With the present invention, it is possible to reduce the deviation between the set value and the actual value of the clutch torque to increase the accuracy of the clutch control and to prevent the excessive load of the clutch unit parts.

Fig. 1 schematically shows a powertrain of a shiftable front-wheel-drive vehicle. The drive torque generated by the engine 11 is transmitted to the transfer case 15 through the main transmission 13 (manual transmission or automatic transmission). The first output side of the transfer case (15) is connected to the rear differential gear (19) via the cardan shaft (17). As a result, the wheels 21 of the rear axle 23 are always driven. Thus, the rear axle 23 forms the primary axle of the vehicle. The second output side of the transfer case is connected to the front axle differential gear 27 via the cardan shaft 25. [ Whereby a part of the driving torque of the engine 11 can be selectively transmitted to the wheels 29 of the front axle 31. [ Thus, the front axle 31 forms the secondary axle of the vehicle.

1, a vehicle dynamic control unit 33 is shown. This unit is connected to the wheel speed sensors 35 and 37 assigned to the wheels 21 of the rear axle 23 and the wheels 29 of the front axle 31. The vehicle dynamic control unit 33 is also connected to additional sensors 39 such as a yaw sensor. The vehicle dynamic control unit 33 generates a control signal in accordance with the signals of the sensors 35, 37 and 39 and the control signal is set to a predetermined drive torque split ratio between the two axles 23 and 31 of the vehicle (Not shown in Fig. 1) of the transfer case 15 for the sake of convenience. In particular, the control signal is a set value of the clutch torque, that is, an amount of torque required for the clutch unit of the transfer case 15.

2 is a schematic cross-sectional view of the transfer case according to Fig. The transfer case 15 includes an input shaft 41, a first output shaft 43, and a second output shaft 45. The first output shaft 43 is coaxially positioned with the input shaft 41 and is formed non-rotatably-preferably, integral with the input shaft. The second output shaft 45 is disposed offset parallel to the input shaft 41.

The transfer case 15 includes a clutch unit 47 having a friction clutch 49 and an actuator 51. [ The friction clutch 49 includes a clutch housing 53 which is non-rotatably connected to the input shaft 41 and the first output shaft 43 and has a plurality of clutch discs. The friction clutch 49 also includes a rotatably supported clutch hub 55 having a plurality of clutch discs alternately interlocking with one another in the disks in the clutch housing 53. The clutch hub 55 is non-rotatably connected to the drive gear wheel 57 of the chain drive 59. The driven gear wheel 61 of the chain drive 59 is non-rotatably connected to the second output shaft 45. Instead of the chain drive 59, for example, a wheel drive having intermediate gear wheels may be provided between the gear wheels 57, 61 described above.

An increase of the drive torque introduced to the transfer case 15 through the input shaft 41 can be transmitted to the second output shaft 45 by operating the actuator 51 in the engagement direction of the friction clutch 49. [

Fig. 3 is a detailed cross-sectional view of the transfer case 15 according to Fig. The actuator 51 includes a support ring 63 rotatably mounted on the input shaft 41 and a rotation axis A of the first output shaft 43 and an adjustment ring 65. [ The support ring 63 is axially supported on the drive gear wheel 57 through a shaft bearing. On the other hand, the adjustment ring 65 is displaceably supported in the axial direction. The support ring 63 and the adjustment ring 65 each include a plurality of ball grooves 67 and 69 on the side surfaces facing each other. The ball grooves extend in a circumferential direction with respect to the axis A and with a ramp shape in the circumferential direction with respect to the axis A with respect to a normal plane. That is, the ball grooves 67 and 69 have a depth varying in the circumferential direction. The ball groove 67 of the support ring 63 and the ball groove 69 of the adjustment ring 65 are placed facing each other and surround the related ball 71. The adjustment ring 65 is displaced in the axial direction by the relative rotation of the support ring 63 and the adjustment ring 65 with respect to each other and at this time the adjustment ring 65 is rotated by the compression ring 65 of the friction clutch 49 (73). The compression ring 73 is pre-pressurized in the disengagement direction of the friction clutch 49 by using the disc spring device 75. [

Separate operation levers 77 and 79 are formed on the support ring 63 and the adjustment ring 65. Individual rolls 81 and 83 are rotatably mounted on the free ends of the levers 77 and 79, respectively. The actuating levers 77 and 79 interact with both end faces 85 and 87 of the control disc 89 which can rotate about the axis C via the rolls 81 and 83. [ The end faces 85 and 87 have circumferentially inclined extensions with respect to the legal plane relative to the axis C. That is, the cross section of the control disk 89 is formed in a wedge shape. Therefore, when the control disk 89 rotates, the operation levers 77 and 79 can move in the form of scissors, so that the support ring 63 and the adjustment ring 65 rotate relative to each other. The control disc 89 has a spline attachment 91 formed integrally. Whereby the control disk 89 can be placed in a driving connection with a reduction gear assigned to the electric motor and the electric motor (not shown in FIG. 3).

Thus, through appropriate control of the motor described above, the control disk 89 can be driven to rotate, with the result that the operating levers 77, 79 perform a relative swing motion. The relative rotation of the support ring 63 and the adjustment ring 65 caused thereby causes axial movement of the adjustment ring 65. Whereby the squeeze ring 73 causes the engagement of the friction clutch 49 or the disengagement of the friction clutch 49 under the support of the disc spring device 75.

3 shows that the lower portion of the housing of the transfer case 15 forms the oil sump 120 and the oil sump accommodates the oil for cooling and lubrication of the friction clutch 49 and the additional parts of the transfer case 15 Viscosity is also known.

Fig. 4 shows a schematic view of the actuator 51 according to Figs. 2 and 3. The actuator 51 includes a controllable electric motor 93 having an armature shaft 95, a reduction gear 97 having a worm gear 99 and a worm wheel 101 and a switching device 103. The rotary motion of the output shaft 105 of the reduction gear 97 is switched by the switching device 103 to the linear movement of the compression ring 73 (Fig. 3). The switching device 103 comprises a control disk 89, a support ring 63, an adjusting ring 65 with operating levers 77 and 79 and balls 71 according to figure 3 . A sensor 197 designed, for example, as an incremental sensor is disposed on the armature shaft 95 of the electric motor 93. As shown in Fig. 4, the sensor 107 may optionally be arranged as a sensor 107 'in the output shaft 105. Fig.

The sensor 107 generates a signal corresponding to the actuator position value. Which corresponds to the actual angle of rotation? 'Of the armature shaft 95 in the illustrated embodiment. This signal? 'Is supplied to the control unit 109 of the transfer case 15. The control device 109 also receives a torque demand M, that is, a set value of the clutch torque, from the vehicle running dynamic control unit 33 (Fig. 1). The control device 109 calculates the rotation angle set value alpha in accordance with the torque demand M from the clutch torque / rotation angle characteristic curve 111 stored in the nonvolatile memory 113 of the control device 109 . The control device 109 generates a control signal for the electric motor 93 to control the friction clutch 49 (Figs. 2 and 3) in accordance with the deviation between the rotation angle set value [alpha] and the rotation angle actual value [ To be adjusted accordingly. Therefore, the control device 109 acts as a position controller.

The control device 109 is designed to calculate the deterioration degree of the oil in the transfer case 15 and to take into account the control of the clutch unit 47. In this case, the characteristic curve 111 of the friction clutch 49 is adapted do. The calculation of the oil deterioration degree is performed by detecting the loss date introduced into the clutch unit 47. To this end, the clutch disc loss output, the drag torque loss output of the clutch unit 47, and the front-end action loss output of the clutch unit 47 are calculated, as described in the introduction section, Integrated.

The control of the clutch unit 47 using the characteristic curve 111 will now be described in more detail with reference to Figs. 5 and 6. Fig. 5 shows a graph in which the required torque (clutch torque setting value) M as a function of the rotation angle set value [alpha] is written as an arbitrary unit and an arbitrary zero crossing point. For example, a characteristic curve 111 originally stored in the memory 113 of the control device 109 and two characteristic curves 111 'and 111 "adapted to compensate for the influence of oil degradation are shown . When the control device 109 receives the required torque M, the relative rotation angle setting value alpha of the electric motor 93 can be calculated using the characteristic curve 111. As a result of the calculated oil deterioration degree If the correction of the clutch control is to be performed, then an adapted characteristic curve 111 'whose slope has been changed can be used instead of the originally stored characteristic curve 111. Using the characteristic curve 111' The friction clutch 49 in this case generates a modified rotation angle set value alpha _{mod that} is smaller than the unchanged rotation angle set value alpha in the originally stored characteristic curve alpha 0.0 > 111 < / RTI > Curve (111 ") describes yet another adaptation of the original strain which is offset stored characteristic curve 111 is changed, which corresponds to the translation of the actuator from the position / clutch torque graph.

For the adaptation of the characteristic curve 111, it is not absolutely necessary that the entire curve stored or its associated table is overwritten. It is sufficient to multiply each required torque M by a correction value according to the degree of wear and then calculate the rotation angle set value alpha on the basis of the characteristic curve 111 originally stored. This process is equivalent to the variation of the characteristic curve slope. That is, the result corresponds to the case where, for example, the adapted characteristic curve 111 'is used. Alternatively, the rotation angle set value alpha is calculated according to the unchanged required torque M and the characteristic curve 111, and the rotation angle set value alpha thus obtained is increased or decreased by the correction value according to the wear rate It is possible. This process is equivalent to the variation of the characteristic curve offset. That is, for example, it corresponds to the use of the parallel shifted characteristic curve 111 ". Depending on the application, it may also be desirable to combine the offset variation and the slope variation with each other. Only one numerical value for each of the offsets is updated, thereby reducing the computational cost to a minimum.

Thus, the characteristic curve adaptation can actually be implemented so that the characteristic curve 111 once stored, as shown in FIG. 6, is always kept unchanged. The changed required torque M _mod is generated by multiplying the current required torque M by the tilt correction value K ₁ for adaptation. Based on the characteristic curve 111, a provisional rotation angle setting value? _Temp corresponding to the changed required torque M _mod is calculated. Subsequently, the offset correction value K ₂ is added to the calculated rotation angle set value alpha _temp to obtain a desired rotation angle set value alpha corresponding to the adaptation. The tilt correction value K ₁ and the offset correction value K ₂ assigned to the current deterioration degree of the oil are called for example from each simple lookup table stored and stored previously by the unique correction of the relevant transfer case 15 . In this case, the characteristic curve 111 stored in the memory 113 of the control device 109 remains unchanged. The slope correction value (K ₁ ) may be smaller than 1, so that multiplication is equivalent to division. Likewise, since the offset correction value K ₂ may be a negative number, addition is equivalent to subtraction.

Referring to Fig. 7, an example of a method of controlling the clutch unit in consideration of the degree of oil deterioration will be described. When it is confirmed in step S1 that the vehicle operation is started (when the control device 109 according to FIG. 4 receives the signal "engine ignition device ON"), in step S2, the degree of deterioration of the oil and the degree of wear of the clutch disk are finally The stored value is called. A predetermined reference value preset on the factory side at the time of starting the vehicle may be called. 5, the slope of the characteristic curve 111 according to Fig. 5 is changed on the basis of the called wear value and, in some cases, additional parameters, in order to obtain the adapted characteristic curve 111 'according to Fig.

Subsequently, in step S4, the clutch unit 47 is controlled in accordance with the changed characteristic curve 111 '. Further, during the drive of the clutch unit 47, the control device 109 continues to calculate the loss output of the clutch unit 47 (for example, through detection of the clutch disk loss output as described in the introduction section) And generates a time integration value for the loss output (step S5).

In step S6, it is checked whether or not the vehicle engine 11 has stopped. When the control device 109 receives the corresponding signal ("engine ignition device OFF"), the oil deterioration degree is updated in step S7. For this purpose, the loss output of the clutch unit 47 calculated subsequently in step S5 is added to the present oil degradation degree. That is, in the embodiment described herein, the loss of the dust introduced into the clutch unit 47 is directly attributable to deterioration. Optionally, the value of the lost day may be multiplied by a predetermined proportionality constant to obtain an adapted wear rate value.

In a similar manner, the wear of the clutch disc is also updated at step S7. To this end, as described above, the correction of the clutch unit 47 is performed first, and the actuator position value associated with the predetermined correction position is calculated. The variation of the disc thickness is calculated based on the difference between the actuator position value calculated through the correction process and the actuator correction value calculated through the immediately preceding correction process and is provided as the clutch disc wear rate. Can be multiplied by a coefficient. Then, the calculated clutch disk wear rate is added to the current clutch disk wear rate.

The updated wear value of the oil and clutch disc is then stored in step S8 and used as the starting value at the next vehicle start-up.

As also described with respect to 6, the characteristic adjustment is one that is performed using the correction value, the deterioration degree and the clutch inclination correction value for the wear of the disc on the basis of the oil in step S3 of the curve (111) (K ₁₎ and offset correction value (K ₂₎ to calculate the number to be read, in which case the correction value s (K _1, K ₂₎ is finally adapted rotation in each set based on the required torque (M) at step S4 value (α) Can be used.

In this way, it can be considered that the lubricating effect of the oil decreases as the wear of the clutch unit 47 becomes higher, for example, so that the clutch characteristic curve changes. The accuracy of the clutch torque control can be increased by compensating for the effect of such wear. The calculated oil degradation may be used for further other purposes, for example, for the purpose of determining the oil change point. Therefore, the oil degradation can also be sent to the CAN bus, for example, and used in other control devices.

Although the present invention is particularly preferably used in a transfer case for electrically driving a friction clutch, it is not limited to the above-described embodiment. As mentioned in the introduction, other devices within the vehicle power train are also possible. Further, the actuator 51 can be designed differently from that described above with reference to the drawings. Other types of reduction gears 97 or other types of switching devices 103 may be provided. Instead of the electric mechanical drive of the illustrated friction clutch 49, electromagnetic, hydraulic or electric hydraulic drive may also be provided. In this case, for example, the pressure / clutch torque characteristic curve instead of the above-described rotational angle / clutch torque characteristic curve 111 is adapted according to the wear degree of the clutch unit.

1 is a schematic view of a vehicle power train;

2 is a schematic view of the transfer case.

3 is a cross-sectional view of the transfer case according to Fig.

4 is a schematic view of a clutch actuator.

5 is a graph showing an example of one uncorrected characteristic curve and two corrected characteristic curves for describing the dependence of the clutch torque on the actuator position.

6 is a graph showing an example of adaptation of a characteristic curve using a slope correction value and an offset correction value.

7 is a flow chart of a method according to the present invention for controlling a clutch unit.

Description of the Related Art

The present invention relates to a differential gear system for an internal combustion engine having an internal combustion engine and an internal combustion engine having the same. A first output shaft and a second output shaft are connected to the output shaft of the first output shaft and the output shaft of the second output shaft, The present invention relates to a clutch drive device and a control method thereof that can be applied to an automatic transmission of an automatic transmission, A ball spring, a ball groove, a ball, a pressing ring, a disc spring, an operating lever, an operating lever, an operating lever, a roll, a roll, Wherein the output shaft is rotatably supported by the output shaft and rotatably supported by the output shaft so that the output shaft is rotatably supported by the output shaft. Sensor, 107 ': upper A sensor is provided with a control device and a control device. The control device includes a clutch torque / rotation angle characteristic curve, a characteristic curve in which the slope is changed, a characteristic curve in which the offset is changed, Α _{mod is the} set value of the rotation angle changed, α _{temp is the} temporary rotation angle set value, M is the required torque, M _{mod is} the required torque to be changed, K ₁ : slope correction value, K ₂ : offset correction value

Claims

A method for controlling a vehicle power train clutch unit (47)

The clutch unit (47)

- a wet friction clutch (49) for controllable torque transmission from the input element (41) of the clutch unit (47) to the output element (45); - said wet friction clutch (49) comprises a first clutch disc and a second clutch disc arranged alternately,

- oil for cooling and lubricating the clutch unit (47); And

- an actuator (51) for driving said wet friction clutch (49)

The method comprises:

Calculating a loss output of the clutch unit (47) to calculate an oil deterioration degree;

- adapting the characteristic curve (111) of the wet friction clutch (49), which describes the dependence of the clutch torque on the actuator control variable, on the basis of the calculated degree of deterioration; And

- controlling the clutch unit (47) according to the characteristic curve (111) by using the actuator (51).

The clutch control apparatus according to claim 1, wherein at least one of a loss output of the clutch disc, a drag torque loss output of the clutch unit (47), and a front- Is calculated by the following formula (1).

The vehicle power train according to claim 2, characterized in that the clutch torque is multiplied by the clutch torque difference between the input element (41) and the output element (45) of the clutch unit (47) Wherein the control unit controls the clutch unit.

4. The method of claim 3, wherein the product of the clutch torque and the rotational speed difference is multiplied by a weighting factor, which is selected according to the clutch torque, the rotational speed difference or the product of the clutch torque and the rotational speed difference. A method of controlling a clutch unit for a train.

The clutch torque control apparatus according to any one of claims 2 to 4, further comprising: a torque sensor for detecting an input element (41) or an output element (45) of the clutch unit (47) And the number of rotations is multiplied.

5. The shift control device according to any one of claims 2 to 4, wherein an efficiency value calculated in an empirical manner to the clutch torque and an output value of the input element (41) or the output element (45) of the clutch unit (47) ) Of the vehicle power train by the number of revolutions of the vehicle power train.

The clutch control apparatus according to any one of claims 2 to 4, wherein at least one output from the group consisting of a clutch disk loss output, a drag torque loss output, and a front- And adding them to each other. &Lt; RTI ID = 0.0 > 11. < / RTI >

The clutch control apparatus according to any one of claims 1 to 3, wherein the clutch unit (47) generates a time integral value with respect to a loss output during calculation of a loss date of the clutch unit Way.

9. The method according to claim 8, characterized in that the lost day of the calculated clutch unit (47) is stored in the nonvolatile memory at the time of vehicle stop so that it is used as a starting value for continuously calculating the oil degradation degree when the vehicle drive is restarted A control method of a clutch unit for a vehicle power train.

4. The vehicle power train clutch unit according to any one of claims 1 to 3, characterized in that at least one of the slope and the offset of the characteristic curve (111) is changed for adaptation of the characteristic curve (111) Control method.

4. A method according to any one of claims 1 to 3, characterized in that wear of the clutch disc is calculated and further adaptation of the wet friction clutch (49) characteristic curve (111) is carried out on the basis of the calculated clutch disc wear- Wherein the control unit determines that the vehicle power train is to be started.

The control method for a vehicle power train clutch unit according to claim 11, wherein the wear degree of the clutch disc is calculated on the basis of the thickness variation of the clutch disc during driving of the clutch unit (47).

The control method of a clutch unit for a vehicle power train according to claim 12, wherein the thickness of the clutch disc is calculated on the basis of an actuator position value calculated in association with a predetermined correction position in a correction process of the clutch unit (47).

A torque transmission device (15) comprising a clutch unit (47) and a control device (109), wherein the clutch unit (47) comprises at least a clutch for transmitting controllable torque from the input element (41) A wet friction clutch with a first clutch disc and a second clutch disc; an oil for cooling and lubricating the clutch unit 47; and an actuator 51 for driving the wet friction clutch 49 ;

The control device (109)

Calculating the loss output of the clutch unit (47) to calculate the degree of deterioration of the oil;

- adapting a characteristic curve (111) of the wet friction clutch (49) which describes the dependence of the clutch torque on the actuator control variable on the basis of the calculated degree of deterioration;

- designed to control the clutch unit (47) according to the characteristic curve (111) using the actuator (51).