Method for controlling a power transmission device for a vehicle

Abstract

A method for controlling a power transmission device for a vehicle is disclosed, comprising a traction motor that transmits power to auxiliary drive wheels of the vehicle, comprising main and auxiliary drive wheels; a traction motor control unit that controls the traction motor; a housing that rotates when receiving the power generated by the traction motor; a first lateral gear connected to a first wheel of the auxiliary drive wheels; a second lateral gear connected to a second wheel of the auxiliary drive wheels; a pinion that meshes with the first lateral gear and the second lateral gear; a cage that supports the pinion and is configured to rotate relative to the housing; a disconnect actuator system (DAS) comprising a locking plate that is supported by the housing to engage with or disengage from the cage; and a DAS controller that controls the DAS.a limited-slip differential (LSD) comprising a drum that can be operationally connected to the housing, a first clutch disc coupled to the drum, a second clutch disc rotatable together with the second lateral gear, and a hydraulic device configured to engage and disengage the first clutch disc and the second clutch disc; and an LSD controller that controls the LSD, the method comprising performing sequence control for the traction motor control unit, the DAS controller, and the LSD controller of the power transmission device, thereby avoiding shocks or damage due to control conflicts.

Description

[0001] This application is based on and claims priority under 35 USC §119 of Korean patent application No. 10-2024-0171625, filed with the Korean Patent Office on October 27, 2024, the disclosure of which is incorporated herein in full by reference. BACKGROUND OF THE INVENTION Area of ​​the invention

[0002] The disclosure relates to a method for controlling a power transmission device for a vehicle. Description of the state of the art

[0003] In general, vehicles are propelled by transferring the power generated by a power source, such as an internal combustion engine or an electric motor, to the wheels, and such a vehicle drivetrain system is divided into a two-wheel drive system, which drives either the front or the rear wheels, and a four-wheel drive system, which drives both the front and rear wheels.

[0004] The four-wheel drive system offers greater driving stability than the two-wheel drive system and is better suited for off-road driving, e.g., in mountainous terrain. The four-wheel drive system is divided into a true all-wheel drive system and a selectable four-wheel drive system.

[0005] The switchable four-wheel drive system uses a power transmission device to distribute power between the front and rear wheels.

[0006] The power transmission device includes a disconnect actuator system (DAS) for switching between two-wheel drive and four-wheel drive, and a limited slip differential (LSD) to prevent a situation in which the vehicle becomes undrivable because, during four-wheel drive, more and more power is transferred to the wheels with low traction and no power to the wheels with high traction.

[0007] Furthermore, the power transmission device includes a DAS controller for controlling the DAS and an LSD controller for controlling the LSD and is controlled by a method for controlling the power transmission device for a vehicle in which the DAS controller and the LSD controller are controlled separately.

[0008] Since the DAS control and the LSD control are controlled separately in such a conventional method for controlling a vehicle's power transmission device, conflicts arise between the control of the DAS and the control of the LSD, leading to shocks or damage. SUMMARY OF THE INVENTION

[0009] Accordingly, one aspect of the disclosure consists of providing a method for controlling a power transmission device for a vehicle that can prevent conflicts between the control of a disconnect actuator system (DAS) and the control of a limited-slip differential (LSD), thereby avoiding shocks or damage.

[0010] According to one embodiment, a method for controlling a power transmission device for a vehicle is provided, comprising a traction motor that transmits power to auxiliary drive wheels of the vehicle, which includes main and auxiliary drive wheels; a traction motor control unit that controls the traction motor; a housing that rotates when receiving the power generated by the traction motor; a first lateral gear connected to a first wheel of the auxiliary drive wheels; a second lateral gear connected to a second wheel of the auxiliary drive wheels; a pinion that meshes with the first lateral gear and the second lateral gear; a cage that supports the pinion and is configured to rotate relative to the housing; a disengaging actuator system (DAS) that includes a locking plate supported by the housing to engage with or disengage from the cage; and a DAS controller that controls the DAS.a limited-slip differential (LSD) comprising a drum that can be operatively connected to the housing, a first clutch disc coupled to the drum, a second clutch disc rotatable together with the second lateral gear, and a hydraulic device configured to engage and disengage the first clutch disc and the second clutch disc; and an LSD controller that controls the LSD, the method comprising performing a sequence control for the drive motor control unit, the DAS controller, and the LSD controller of the power transmission device.

[0011] The procedure may further include: a drive mode determination step to determine a drive mode; a first sequence control step to operate the drive motor control unit, the DAS control, and the LSD control based on a predetermined first sequence control to perform a transition to a four-wheel drive mode when the transition from a two-wheel drive mode to the four-wheel drive mode is determined in the drive mode determination step; and a second sequence control step to operate the drive motor control unit, the DAS control, and the LSD control based on a predetermined second sequence control to perform a transition to the two-wheel drive mode when the transition from the four-wheel drive mode to the two-wheel drive mode is determined in the drive mode determination step.

[0012] The drive mode determination step may include: a first drive mode determination step to determine whether a drive mode received from a vehicle control unit (VCU) is the two-wheel drive mode or the four-wheel drive mode; a second drive mode determination step to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode if the first drive mode determination step determines that the received drive mode is the four-wheel drive mode;and a third drive mode determination step to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode, if in the first drive mode determination step it is determined that the received drive mode is the two-wheel drive mode, and the determination of the two-wheel drive mode in the second drive mode determination step can be seen as the transition from the two-wheel drive mode to the four-wheel drive mode and thus the first sequence control step can be carried out, and the determination of the four-wheel drive mode in the third drive mode determination step can be seen as the transition from the four-wheel drive mode to the two-wheel drive mode, and thus the second sequence control step can be carried out.

[0013] The first sequence control step may include: a traction motor-auxiliary drive wheel speed synchronization step to synchronize the speed of the traction motor with the speed of the auxiliary drive wheel by means of the traction motor control unit; a DAS engagement step to synchronize the housing with the cage by bringing the locking plate into contact with the cage by means of the DAS control; an LSD responsiveness assurance step to ensure the responsiveness of the LSD by increasing the pressure of the hydraulic device by means of the LSD control; and an LSD drive torque control step to control the drive torque of the LSD by adjusting the pressure of the hydraulic device based on the driving conditions by means of the LSD control unit.

[0014] The traction motor-auxiliary drive wheel speed synchronization step may include: a traction motor-auxiliary drive wheel speed synchronization test step to set the speed of the traction motor using the traction motor control unit; and a traction motor-auxiliary drive wheel speed synchronization determination step to determine whether a difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within a predetermined speed range, wherein the traction motor-auxiliary drive wheel speed synchronization determination step may be performed after the traction motor-auxiliary drive wheel speed synchronization test step, and the DAS engagement step and the LSD responsiveness assurance step may be performed if the traction motor-auxiliary drive wheel speed synchronization determination step determines that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within the predetermined speed range.and the traction motor-auxiliary drive wheel speed synchronization test step can be repeated if it is determined that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel does not fall within the specified speed range.

[0015] The DAS engagement step can include the following: a DAS engagement test step to move the locking plate closer to the cage using the DAS control; a DAS engagement determination step to determine whether a movement distance of the locking plate falls within a predetermined distance range;and a DAS engagement signal transmission step for transmitting a DAS engagement signal indicating that the housing is synchronized with the cage, wherein the DAS engagement determination step can be performed after the DAS engagement test step, the DAS engagement signal transmission step and the LSD drive torque control step can be performed sequentially if the DAS engagement determination step determines that the movement distance of the locking plate falls within the specified distance range, and wherein the DAS engagement test step can be performed again if the DAS engagement determination step determines that the movement distance of the locking plate does not fall within the specified distance range.

[0016] The LSD responsiveness assurance step may include: an LSD responsiveness assurance test step to increase the pressure of the hydraulic device using the LSD control;and an LSD responsiveness assurance determination step to determine whether the pressure of the hydraulic device falls within a predetermined pressure range, wherein the LSD responsiveness assurance determination step can be performed after the LSD responsiveness assurance test step, the DAS engagement determination step can be performed if the LSD responsiveness assurance determination step determines that the pressure of the hydraulic device falls within the predetermined pressure range, and wherein the LSD responsiveness assurance test step can be performed again if the LSD responsiveness assurance determination step determines that the pressure of the hydraulic device does not fall within the predetermined pressure range.

[0017] The DAS engagement determination step can be performed after the DAS engagement test step has been carried out and it has been determined, in the LSD reactivity assurance determination step, that the pressure of the hydraulic device falls within the specified pressure range.

[0018] The minimum value of the specified pressure range can be set higher for LSDs with low reactivity than for LSDs with high reactivity.

[0019] The second sequence control step may include: a DAS disengagement step to desynchronize the housing from the cage by separating the locking plate from the cage using the DAS control; an LSD pressure release step to release the pressure of the hydraulic device using the LSD control; and an LSD drive torque non-control step in which the drive torque of the LSD is not controlled.

[0020] The DAS release step can include the following: a DAS release attempt step to move the locking plate away from the cage using the DAS control; a DAS release determination step to determine whether the movement distance of the locking plate falls within a predetermined distance range;and a DAS release signal transmission step for transmitting a DAS release signal indicating that the housing is not synchronized with the cage, wherein the DAS release determination step can be performed after the DAS release test step, the DAS release signal transmission step and the LSD drive torque non-control step can be performed sequentially if the DAS release determination step determines that the locking plate movement distance falls within the specified distance range, and wherein the DAS release test step can be performed again if the DAS release determination step determines that the locking plate movement distance does not fall within the specified distance range.

[0021] The LSD pressure release step can include: an LSD pressure release test step to reduce the pressure of the hydraulic device by means of the LSD control; and an LSD pressure release determination step to compare the pressure of the hydraulic device with a predetermined pressure, wherein the LSD pressure release test step can be performed after the DAS disengagement test step, the LSD pressure release determination step can be performed after the LSD pressure release test step, the DAS disengagement determination step can be performed if the LSD pressure release determination step determines that the pressure of the hydraulic device is lower than the predetermined pressure, and the LSD pressure release test step can be performed again if the LSD pressure release determination step determines that the pressure of the hydraulic device is higher than or equal to the predetermined pressure.

[0022] In the LSD pressure release test step, the pressure of the hydraulic device can be reduced by a method selected between a method that uses a motor and a method that uses gravity and clutch jerking.

[0023] The procedure may further include an LSD drive torque control step in which the drive torque of the LSD is controlled by adjusting the pressure of the hydraulic device based on the driving conditions by means of the LSD control, if in the drive mode determination step it is determined that the four-wheel drive mode, which was a previous drive mode, is to be retained.

[0024] The procedure may further include an LSD drive torque non-control step in which the drive torque of the LSD is not controlled if, in the drive mode determination step, it is determined that the two-wheel drive mode, which was a previous drive mode, is to be retained. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a flowchart showing part of a method for controlling a power transmission device for a vehicle according to an embodiment of the disclosure, Fig. Figure 2 is a flowchart that illustrates another part of the procedure for controlling the power transmission device for a vehicle in Fig. 1 shows, Fig. Figure 3 is a flowchart that shows another part of the procedure for controlling a power transmission device for a vehicle in Fig. 1 shows, Fig. 4 is a system diagram showing a power transmission device for a vehicle operating in a two-wheel drive mode by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled, Fig. 5 is a system diagram showing a power transmission device for a vehicle operating in four-wheel drive mode by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled, and Fig. Figure 6 is a system diagram showing a power transmission device for a vehicle operating in a four-wheel drive and differential-limiting mode, as described by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following describes in detail a method for controlling a power transmission device for a vehicle according to the disclosure with reference to the accompanying drawings.

[0026] Fig. Figure 1 is a flowchart showing part of a method for controlling a power transmission device for a vehicle according to an embodiment of the disclosure, Fig. Figure 2 is a flowchart that illustrates another part of the procedure for controlling the power transmission device for a vehicle in Fig. 1 shows, Fig. Figure 3 is a flowchart that shows another part of the procedure for controlling a power transmission device for a vehicle in Fig. 1 shows, Fig. 4 is a system diagram showing a power transmission device for a vehicle operating in a two-wheel drive mode by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled, Fig. 5 is a system diagram showing a power transmission device for a vehicle operating in four-wheel drive mode by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled, and Fig. Figure 6 is a system diagram showing a power transmission device for a vehicle operating in a four-wheel drive and differential-limiting mode, as described by the method for controlling the power transmission device for a vehicle in Fig. 1, Fig. 2 to Fig. 3 is controlled.

[0027] As in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. As shown in Figure 6, the power transmission device for a vehicle according to an embodiment of the disclosure can include a drive motor for transmitting power to the auxiliary drive wheels of the vehicle with main and auxiliary drive wheels and a drive motor control unit for controlling the drive motor.

[0028] Furthermore, the power transmission device for a vehicle may also include a housing 100 which rotates when receiving the power generated by the drive motor, a first lateral gear 200 which is connected to a first wheel of the auxiliary drive wheels, a second lateral gear 300 which is connected to a second wheel of the auxiliary drive wheels, a pinion 400 which meshes with the first lateral gear 200 and the second lateral gear 300, a cage 500 which carries the pinion 400 and is designed to rotate relative to the housing 100, a disconnect actuator system (DAS) 600 which includes a locking plate 610 which is carried by the housing 100 to engage with or be disengaged from the cage 500, and a DAS controller which controls the DAS 600.

[0029] Furthermore, the power transmission device for a vehicle also includes a limited-slip differential (LSD) 700, which prevents a situation in which the vehicle becomes inoperable because, in four-wheel drive mode, more and more power is transmitted to the wheels with low traction and no power to the wheels with high traction, as well as an LSD control unit that controls the LSD 700. The LSD 700 can include a drum 710 that can be operatively connected to the housing 100, a first clutch disc coupled to the drum 710, a second clutch disc that is rotatable together with the second side gear 300, and a hydraulic device configured to engage and disengage the first and second clutch discs.

[0030] The first clutch disc and the second clutch disc form a clutch pack 720.

[0031] Simultaneously, the power transmission device for a vehicle is controlled by a method for controlling the power transmission device for a vehicle according to this embodiment. The method for controlling the power transmission device for a vehicle may include performing sequence control for the drive motor control unit, the DAS control, and the LSD control.

[0032] In particular, the method for controlling the power transmission device for a vehicle according to this embodiment may include a drive mode determination step S1 for determining a drive mode.

[0033] The drive mode determination step S1 may include a first drive mode determination step S11 to determine whether a drive mode received from a vehicle control unit (VCU) is the two-wheel drive mode or the four-wheel drive mode, a second drive mode determination step S12 to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode if the first drive mode determination step S11 determines that the received drive mode is the four-wheel drive mode, and a third drive mode determination step S13 to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode if the first drive mode determination step S11 determines that the received drive mode is the two-wheel drive mode.

[0034] Furthermore, the method for controlling the power transmission device for a vehicle may also include a first sequence control step S2 for operating the drive motor control unit, the DAS control and the LSD control based on a predetermined first sequence control to perform a transition to four-wheel drive mode when the transition from two-wheel drive mode to four-wheel drive mode is determined in the drive mode determination step S1.

[0035] The first sequence control step S2 can include a traction motor auxiliary drive wheel speed synchronization step S21 for synchronizing the speed of the traction motor with the speed of the auxiliary drive wheel by means of the traction motor control unit.

[0036] The traction motor auxiliary drive wheel speed synchronization step S21 can include a traction motor auxiliary drive wheel speed synchronization test step S211 for adjusting the speed of the traction motor using the traction motor control unit.

[0037] Furthermore, the traction motor auxiliary drive wheel speed synchronization step S21 can include a traction motor auxiliary drive wheel speed synchronization determination step S212 to determine whether a difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within a specified speed range.

[0038] Furthermore, the first sequence control step S2 can also include a DAS engagement step S22, in which the housing 100 is synchronized with the cage 500 by bringing the locking plate 610 into contact with the cage 500 by means of the DAS control.

[0039] The DAS engagement step S22 can include a DAS engagement test step S221 to move the locking plate 610 closer to the cage 500 by means of the DAS control.

[0040] Furthermore, the DAS indentation step S22 can also include a DAS indentation determination step S222 to determine whether a movement distance of the locking plate 610 falls within a specified distance range.

[0041] Furthermore, the DAS connection step S22 may also include a DAS engagement signal transmission step S223 to transmit a DAS engagement signal indicating that the housing 100 is synchronized with the cage 500.

[0042] Furthermore, the first sequence control step S2 can also include an LSD responsiveness assurance step S23 to ensure the responsiveness of the LSD 700 by increasing the pressure of the hydraulic device by means of the LSD control.

[0043] The LSD responsiveness assurance step S23 may include an LSD responsiveness assurance test step S231 to increase the pressure of the hydraulic device by means of the LSD control.

[0044] Furthermore, the LSD responsiveness assurance step S23 may also include an LSD responsiveness assurance determination step S232 to determine whether the pressure of the hydraulic device falls within a specified pressure range.

[0045] The specified pressure range can be adjusted according to the reactivity characteristics of the LSD. In other words, the minimum value Pmin of the specified pressure range can be set higher, for example, if the reactivity of the LSD 700 is low (when a high preload is required to ensure responsiveness), than if the reactivity of the LSD 700 is high (when sufficient responsiveness can be ensured even with a low preload).

[0046] Furthermore, the first sequence control step S2 can also include an LSD drive torque control step S24 for controlling the drive torque of the LSD 700 by adjusting the pressure of the hydraulic device based on the driving conditions using the LSD control.

[0047] Furthermore, the method for controlling the power transmission device for a vehicle may also include a second sequence control step S3 for operating the drive motor control unit, the DAS control and the LSD control based on a predetermined second sequence control to perform a transition to the two-wheel drive mode when the transition from the four-wheel drive mode to the two-wheel drive mode is determined in the drive mode determination step S1.

[0048] The second sequence control step S3 can include a DAS release step S31 to desynchronize the housing 100 from the cage 500 by separating the locking plate 610 from the cage 500 using DAS control.

[0049] The DAS release step S31 can include a DAS release attempt step S311 to move the locking plate 610 away from the cage 500 by means of the DAS control.

[0050] Furthermore, the DAS disengagement step S31 can also include a DAS disengagement step determination step S312 to determine whether the movement distance of the locking plate 610 falls within a specified distance range.

[0051] Furthermore, the DAS release step S31 may also include a DAS release signal transmission step S313 to transmit a DAS release signal indicating that the housing 100 is not synchronized with the cage 500.

[0052] Furthermore, the second sequence control step S3 can also include an LSD pressure release step S32 for releasing the pressure of the hydraulic device by means of the LSD control.

[0053] The LSD pressure release step S32 can include an LSD pressure release test step S321 for reducing the pressure of the hydraulic device by means of the LSD control.

[0054] In this LSD pressure release test step S321, the pressure of the hydraulic device in the LSD pressure release test step can be reduced by a method that is selected between a method that uses a motor, which is disadvantageous in terms of noise generation and side effects, but advantageous in terms of pressure release rate, and a method that uses gravity and clutch jerking, which is disadvantageous in terms of pressure release rate, but advantageous in terms of noise generation and side effects.

[0055] Furthermore, the second pressure release step S32 may also include an LSD pressure release determination step S322 for comparing the pressure of the hydraulic device with a predetermined pressure.

[0056] Furthermore, the second sequence control step S3 can also include an LSD drive torque non-control step S33, in which the drive torque of the LSD 700 is not controlled.

[0057] If, in the second drive mode determination step S12, the current drive mode is determined to be two-wheel drive mode, this is considered the transition from two-wheel drive mode to four-wheel drive mode, and thus the first sequence control step S2 can be carried out.

[0058] On the other hand, if the current drive mode is determined to be the four-wheel drive mode in the second drive mode determination step S12, this is considered to be the retention of the previous drive mode, i.e. the four-wheel drive mode, and thus the LSD drive torque control step S24 can be performed.

[0059] If the current drive mode is determined to be the four-wheel drive mode in the third drive mode determination step S13, this is considered a transition from the four-wheel drive mode to the two-wheel drive mode, so that the second sequence control step S3 can be carried out.

[0060] If, on the other hand, the current drive mode is determined to be the two-wheel drive mode in the third drive mode determination step S13, this is considered to be the retention of the previous drive mode, i.e. the two-wheel drive mode, and thus the LSD drive torque non-control step S33 can be performed.

[0061] At the same time, in the first sequence control step S2, the traction motor auxiliary drive wheel speed synchronization determination step S212 can be carried out after the traction motor auxiliary drive wheel speed synchronization test step S211.

[0062] Furthermore, if in the traction motor auxiliary drive wheel speed synchronization determination step S212 it is determined that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within the specified speed range, the DAS engagement step S22 and the LSD responsiveness assurance step S23 can be performed.

[0063] If, on the other hand, it is determined that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel does not fall within the specified speed range, the traction motor-auxiliary drive wheel speed synchronization test step S211 can be performed again.

[0064] Furthermore, in the first sequence control step S2, the DAS engagement determination step S222 can be carried out after the DAS engagement test step S221.

[0065] If, in the DAS engagement determination step S222, it is determined that the movement distance of the locking plate 610 falls within the specified distance range, the DAS engagement signal transmission step S223 and the LSD drive torque control step S24 can also be carried out sequentially.

[0066] If, on the other hand, it is determined in the DAS engagement step S222 that the movement distance of the locking plate 610 does not fall within the specified distance range, the DAS engagement test step S221 can be performed again.

[0067] Furthermore, in the first process control step S2, the LSD reactivity assurance determination step S232 can be carried out after the LSD reactivity assurance test step S231.

[0068] If, in the LSD reactivity assurance determination step S232, it is determined that the pressure of the hydraulic device falls within the specified pressure range, the DAS engagement determination step S222 can also be performed.

[0069] If, on the other hand, it is determined in the LSD responsiveness assurance test step S232 that the pressure of the hydraulic device does not fall within the specified pressure range, the LSD responsiveness assurance test step S231 can be carried out again.

[0070] The DAS engagement determination step S222 can be performed if the DAS engagement test step S221 is performed and in the LSD responsiveness assurance determination step S232 it is determined that the pressure of the hydraulic device falls within the specified pressure range.

[0071] At the same time, in the second sequence control step S3, the DAS release determination step S312 can be carried out after the DAS release attempt step S311.

[0072] If, in the DAS release determination step S312, it is determined that the movement distance of the locking plate 610 falls within the specified distance range, the DAS release signal transmission step S313 and the LSD drive torque control step S33 can also be carried out one after the other.

[0073] On the other hand, if it is determined in the DAS disengagement determination step S312 that the movement distance of the locking plate 610 does not fall within the specified distance range, the DAS engagement test step S311 can be performed again.

[0074] Furthermore, in the second sequence control step S3, the LSD pressure release test step S321 can be carried out after the DAS release test step S311.

[0075] Furthermore, the LSD pressure release determination step S322 can be performed after the LSD pressure release test step S321.

[0076] Furthermore, if the LSD pressure release determination step S322 determines that the pressure of the hydraulic device is lower than the specified pressure, the DAS release determination step S312 can be performed.

[0077] If, on the other hand, it is determined in the LSD pressure release determination step S322 that the pressure of the hydraulic device is higher than or equal to the specified pressure, the LSD pressure release test step S321 can be carried out again.

[0078] The following describes the operational effects of the method for controlling the power transmission device for a vehicle according to an exemplary embodiment.

[0079] That means when the vehicle is driven in two-wheel drive mode, as in Fig. As shown in Figure 4, a command to switch to four-wheel drive mode can be received from the vehicle control unit. Then, as shown in Fig. As shown in Figure 1, the first sequence control step S2 can be performed by executing the first drive mode determination step S11 and the second drive mode determination step S12. Then, as ... Fig. As shown in Figure 2, the traction motor-auxiliary drive wheel speed synchronization step S21 can be performed so that the speed of the traction motor can be synchronized with the speed of the auxiliary drive wheel. Then, the DAS engagement step S22 and the LSD responsiveness assurance step S23 can be performed simultaneously. When the responsiveness of the LSD 700 is ensured to complete the engagement of the DAS 600, the LSD drive torque control step S24 is performed so that the vehicle engages in four-wheel drive mode. Fig. 5 or the four-wheel drive and differential limiting mode from Fig. 6 can be powered.

[0080] In the case of four-wheel drive mode, this means... Fig. 5. The housing 100 and the drum 710 are not coupled. In the case of four-wheel drive and differential limiting mode, off. Fig. 6 the housing 100 and the drum 710 are coupled and restricted via a keyway of a drive shaft which connects the second side gear 300 and the second wheel.

[0081] If a command to drive in four-wheel drive mode is received from the vehicle control unit, but the current drive mode is four-wheel drive, the LSD drive torque control step S24, which is currently being performed, can still be carried out. In other words, as described in Fig. 1 and Fig. Figure 2 shows that the LSD drive torque control step S24 is performed directly after performing the first drive mode determination step S11 and the second drive mode determination step S12.

[0082] When the vehicle is in four-wheel drive mode Fig. 5 or the four-wheel drive and differential limiting mode from Fig. When the vehicle is driven by the 6-wheel drive system, a command to switch to two-wheel drive mode can be received from the vehicle control unit. Then, as described in Fig. As shown in Figure 1, the second sequence control step S3 can be performed by executing the first drive mode determination step S11 and the third drive mode determination step S13. Then, as ... Fig. As shown in Figure 3, the DAS disengagement step S31 and the LSD pressure release step S32 can be performed. Furthermore, when the pressure of the LSD 700 is released to complete the disengagement of the DAS 600, the LSD drive torque non-control step S33 is performed, so that the vehicle is in two-wheel drive mode. Fig. 4 can be driven.

[0083] If a command to drive in two-wheel drive mode is received from the vehicle control unit, but the current drive mode is two-wheel drive, the LSD drive torque non-control step S33, which is currently being performed, can continue. In other words, as described in Fig. 1 and Fig. Figure 3 shows that the LSD drive torque non-control step S33 is performed directly after performing the first drive mode determination step S11 and the third drive mode determination step S13.

[0084] In one embodiment, the method for controlling the power transmission device for a vehicle can include performing the sequence control for the drive motor control unit, the DAS control and the LSD control in order to avoid conflicts between the control of the DAS 600 and the control of the LSD 700 and thereby prevent shocks or damage.

[0085] In particular, the method for controlling the power transmission device for a vehicle includes the first sequence control step S2, and the first sequence control step S2 includes the traction motor auxiliary drive wheel speed synchronization test step S211, the traction motor auxiliary drive wheel speed synchronization determination step S212, the DAS engagement test step S221, the DAS engagement determination step S222, the DAS engagement signal transmission step S223, the LSD responsiveness assurance test step S231, the LSD responsiveness assurance determination step S232, and the LSD drive torque control step S24, which are integral and interconnected according to a predetermined first sequence control, thereby effectively avoiding shocks or damage during the transition from the two-wheel drive mode to the four-wheel drive mode or to the four-wheel drive and differential limiting mode.

[0086] Furthermore, the procedure for controlling the power transmission device for a vehicle includes the second sequence control step S3, and the second sequence control step S3 includes the DAS disengagement test step S311, the DAS disengagement determination step S312, the DAS disengagement signal transmission step S313, the LSD pressure release test step S321, the LSD pressure release determination step S322, and the LSD drive torque non-control step S33, which are integral and interconnected according to a predetermined second sequence control, thereby effectively avoiding shocks or damage during the transition from the four-wheel drive mode or the four-wheel drive and differential limiting mode to the two-wheel drive mode. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] KR 10-2024-0171625

[0001]

Claims

[1] Method for controlling a power transmission device for a vehicle, comprising a traction motor that transmits power to auxiliary drive wheels of the vehicle, which includes main and auxiliary drive wheels; a traction motor control unit that controls the traction motor; a housing that rotates when receiving the power generated by the traction motor; a first lateral gear connected to a first wheel of the auxiliary drive wheels; a second lateral gear connected to a second wheel of the auxiliary drive wheels; a pinion that meshes with the first lateral gear and the second lateral gear; a cage that supports the pinion and is configured to rotate relative to the housing; a disconnect actuator system (DAS) comprising a locking plate that is supported by the housing to engage with or disengage from the cage; a DAS controller that controls the DAS;a limited-slip differential (LSD) comprising a drum that can be operatively connected to the housing, a first clutch disc coupled to the drum, a second clutch disc rotatable together with the second lateral gear, and a hydraulic device configured to engage and disengage the first clutch disc and the second clutch disc; and an LSD controller that controls the LSD, the method comprising performing a sequence control for the drive motor control unit, the DAS controller, and the LSD controller of the power transmission device. [2] The method of claim 1, further comprising: a drive mode determination step to determine a drive mode; a first sequence control step to operate the drive motor control unit, the DAS control, and the LSD control based on a predefined first sequence control to perform a transition to a four-wheel drive mode when the transition from a two-wheel drive mode to the four-wheel drive mode is determined in the drive mode determination step; and a second sequence control step to operate the drive motor control unit, the DAS control and the LSD control based on a predefined second sequence control to perform a transition to the two-wheel drive mode when the transition from the four-wheel drive mode to the two-wheel drive mode is determined in the drive mode determination step. [3] Method according to claim 2, wherein the drive mode determination step comprises: a first drive mode determination step to determine whether a drive mode received from a vehicle control unit (VCU) is the two-wheel drive mode or the four-wheel drive mode; a second drive mode determination step to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode, if the first drive mode determination step determines that the received drive mode is the four-wheel drive mode; and a third drive mode determination step to determine whether the current drive mode is the two-wheel drive mode or the four-wheel drive mode, if the first drive mode determination step determines that the received drive mode is the two-wheel drive mode, and The determination of the two-wheel drive mode in the second drive mode determination step is considered the transition from the two-wheel drive mode to the four-wheel drive mode, and thus the first sequence control step is carried out, and The determination of the four-wheel drive mode in the third drive mode determination step is considered the transition from the four-wheel drive mode to the two-wheel drive mode, and thus the second sequence control step is carried out. [4] Method according to claim 2 or 3, wherein the first sequence control step comprises: a traction motor-auxiliary drive wheel speed synchronization step for synchronizing the speed of the traction motor with the speed of the auxiliary drive wheel by the traction motor control unit; a DAS indentation step to synchronize the housing with the cage by bringing the locking plate into contact with the cage via the DAS control; an LSD responsiveness assurance step to ensure the responsiveness of the LSD by increasing the pressure of the hydraulic device through the LSD control; and an LSD drive torque control step for controlling the drive torque of the LSD by adjusting the pressure of the hydraulic device using the LSD control unit based on driving conditions. [5] Method according to claim 4, wherein the traction motor auxiliary drive wheel speed synchronization step comprises: a traction motor auxiliary drive wheel speed synchronization test step for adjusting the speed of the traction motor by the traction motor control unit; and a traction motor-auxiliary drive wheel speed synchronization determination step to determine whether a difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within a predetermined speed range, wherein the traction motor auxiliary drive wheel speed synchronization determination step is performed after the traction motor auxiliary drive wheel speed synchronization test step, The DAS engagement step and the LSD responsiveness assurance step are performed when, in the traction motor-auxiliary drive wheel speed synchronization determination step, it is determined that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel falls within the specified speed range, and The traction motor-auxiliary drive wheel speed synchronization test step is repeated if it is determined that the difference between the speed of the traction motor and the speed of the auxiliary drive wheel does not fall within the specified speed range. [6] Method according to claim 4 or 5, wherein the DAS indentation step comprises: a DAS engagement test step to move the locking plate closer to the cage using the DAS control; a DAS indentation determination step to determine whether a movement distance of the locking plate falls within a predefined distance range; and a DAS engagement signal transmission step to transmit a DAS engagement signal indicating that the enclosure is synchronized with the cage, where the DAS engagement determination step is performed after the DAS engagement test step, The DAS engagement signal transmission step and the LSD drive torque control step are performed sequentially if, in the DAS engagement determination step, it is determined that the movement distance of the locking plate falls within the specified distance range, and the DAS engagement test step is repeated if the DAS engagement determination step determines that the movement distance of the locking plate does not fall within the specified distance range. [7] Method according to claim 6, wherein the LSD reactivity assurance step comprises: an LSD responsiveness assurance test step to increase the pressure of the hydraulic device by means of the LSD control; and an LSD reactivity assurance step to determine whether the pressure of the hydraulic device falls within a predetermined pressure range, where the LSD reactivity assessment step is performed after the LSD reactivity assessment test step, The DAS engagement step is performed when the LSD responsiveness assurance step determines that the pressure of the hydraulic device falls within the specified pressure range, and wherein the LSD responsiveness assurance test step is repeated if the LSD responsiveness assurance determination step determines that the pressure of the hydraulic device does not fall within the specified pressure range. [8] Method according to claim 7, wherein the DAS engagement determination step is carried out after performing the DAS engagement test step and determining, in the LSD responsiveness assurance determination step, that the pressure of the hydraulic device falls into the predetermined pressure range. [9] Method according to claim 7 or 8, wherein the minimum value of the predetermined pressure range is set higher for low reactivity of the LSD than for high reactivity of the LSD. [10] Method according to any of the preceding claims which includes at least the features of claim 2, wherein the second sequence control step comprises: a DAS release step to desynchronize the housing from the cage by separating the locking plate from the cage using DAS control; an LSD pressure release determination step for releasing the pressure of the hydraulic device through the LSD control; and an LSD drive torque non-control step in which the drive torque of the LSD is not controlled. [11] Method according to claim 10, wherein the DAS ejection step comprises: a DAS release attempt step to move the locking plate away from the cage using the DAS control; a DAS release determination step to determine whether the movement distance of the locking plate falls within a predefined distance range; and a DAS release signal transmission step to transmit a DAS release signal indicating that the housing is not synchronized with the cage, where the DAS release determination step is performed after the DAS release attempt step, The DAS release signal transmission step and the LSD drive torque non-control step are performed sequentially if, in the DAS release determination step, it is determined that the movement distance of the locking plate falls within the specified distance range, and the DAS release test step is repeated if the DAS release determination step determines that the movement distance of the locking plate does not fall within the specified distance range. [12] The method of claim 11, wherein the LSD pressure release step comprises: an LSD pressure release test step to reduce the pressure of the hydraulic device by the LSD control; and an LSD pressure release determination step to compare the pressure of the hydraulic device with a predetermined pressure, where the LSD pressure release test step is performed after the DAS ejection test step, the LSD pressure release determination step is performed after the LSD pressure release test step, The DAS release determination step is performed when the LSD pressure release determination step determines that the pressure of the hydraulic device is lower than the specified pressure, and The LSD pressure release test step is repeated if the LSD pressure release determination step determines that the pressure of the hydraulic device is higher than or equal to the specified pressure. [13] Method according to claim 12, wherein in the LSD pressure release test step the pressure of the hydraulic device is reduced by a method selected between a method using a motor and a method using gravity and clutch jerking. [14] Method according to any of the preceding claims which includes at least the features of claim 2, which further comprises an LSD drive torque control step wherein the drive torque of the LSD is controlled by adjusting the pressure of the hydraulic device based on the driving conditions by means of the LSD control, when in the drive mode determination step it is determined that the four-wheel drive mode which was a previous drive mode is to be retained. [15] Method according to any of the preceding claims which includes at least the features of claim 2, further comprising an LSD drive torque non-control step in which the drive torque of the LSD is not controlled when, in the drive mode determination step, it is determined that the two-wheel drive mode, which was a previous drive mode, is to be retained.

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