POWERTRAIN METHOD AND APPARATUS

Abstract

A powertrain of a vehicle can be operated. The powertrain can have at least one transmission housing, a clutch assembly which is arranged therein and which comprises a clutch that operates in a positively locking manner, and an actuation unit for actuating the clutch. The clutch comprises at least one first clutch component, which can be moved along an axial direction, and a second clutch component, said clutch components being connected together in a form-fitting manner upon actuating the clutch; wherein the actuation unit comprises an electromagnetic actuator with a piston, and the piston is moved from a starting position into an end position along the axial direction upon actuating the clutch, thereby moving the first clutch component.

Claims

1.-7. (canceled)

8. A method for operating a powertrain of a vehicle, wherein the powertrain has at least one transmission housing and a clutch assembly arranged therein with a clutch that operates interlockingly as well as an actuator for actuating the clutch; wherein the clutch comprises at least a first clutch component displaceable in an axial direction and a second clutch component which are interlockingly connected to one another when the clutch is actuated; wherein the actuator comprises an electromagnetic actuator with a piston; wherein the piston is displaced from a starting position in the axial direction into an end position when the clutch is actuated and thereby displaces the first clutch component; wherein the clutch components are interlockingly connected to one another only after a synchronization state has been reached; wherein at least the piston and the clutch are at least partially acted upon by a transmission fluid; the method comprising: a) determining a request to actuate the clutch and to establish an interlocking connection between the clutch components; b) energizing the actuator with a bias current, wherein the piston remains in the starting position; c) initiating a synchronization of speeds of the clutch components; d) determining that the synchronization state has been reached by the clutch components; and e) energizing the actuator with an actuating current, wherein the piston is displaced from the starting position into the end position.

9. The method of claim 8, wherein the bias current is at least 20% of the actuating current.

10. The method of claim 8, wherein a value of the bias current is kept constant until step e) is initiated.

11. The method of claim 8, wherein the actuating current is at most 6 amperes.

12. The method of claim 8, wherein static friction of the components of the clutch assembly displaced during actuation of the actuator is only overcome by the actuator when the bias current is exceeded.

13. The method of claim 12, wherein the components include the piston and at least one of: a sliding disk, which is arranged between the piston and a sensor disk; a sensor disk which interacts with a position sensor to determine a position of the piston; a return spring which, as an energy store element, provides a force for the return movement of the piston from the end position back to the starting position; or a cam ring as the first clutch component.

14. An apparatus for a powertrain of a vehicle, comprising: a transmission housing and a clutch assembly arranged therein with a clutch that operates interlockingly; an actuator arranged to actuate the clutch; wherein the clutch comprises at least a first clutch component displaceable in an axial direction and a second clutch component that are interlockingly connected to one another when the clutch is actuated; wherein the actuator comprises an electromagnetic actuator with a piston that is displaceable from a starting position in the axial direction into an end position when the clutch is actuated to thereby displaces the first clutch component; wherein the clutch components can only be interlockingly connected to one another after a synchronization state has been reached; wherein at least the piston and the clutch are at least partially acted upon by a transmission fluid; and a control unit programmed to: a) determine a request to actuate the clutch and to establish an interlocking connection between the clutch components; b) energize the actuator with a bias current, wherein the piston remains in the starting position; c) initiate a synchronization of speeds of the clutch components; d) determine that the synchronization state has been reached by the clutch components; and e) energize the actuator with an actuating current, wherein the piston is displaced from the starting position into the end position.

15. The apparatus of claim 14, wherein the bias current is at least 20% of the actuating current.

16. The apparatus of claim 14, wherein a value of the bias current is kept constant until step e) is initiated.

17. The apparatus of claim 14, wherein the actuating current is at most 6 amperes.

18. The apparatus of claim 14, wherein static friction of the components of the clutch assembly displaced during actuation of the actuator is only overcome by the actuator when the bias current is exceeded.

19. The apparatus of claim 18, wherein the components include the piston and at least one of: a sliding disk, which is arranged between the piston and a sensor disk; a sensor disk which interacts with a position sensor to determine a position of the piston; a return spring which, as an energy store element, provides a force for the return movement of the piston from the end position back to the starting position; or a cam ring as the first clutch component.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0062] The disclosure explained in greater detail below with reference to the appended figures. It should be noted that the invention is not intended to be limited by the embodiments described. Typically, unless explicitly shown otherwise, it is also possible to extract partial aspects of the substantive matter explained in the figures and to combine them with other components and findings from the present description. Typically, it should be noted that the figures and especially the proportions shown are only schematic.

[0063] In the figures:

[0064] FIG. 1: shows a partial view of a powertrain in a side view in section; and

[0065] FIG. 2: shows a graph containing several curves.

DESCRIPTION

[0066] FIG. 1 shows a partial view of a powertrain 1 in a side view in section. The powertrain 1 is part of a vehicle 2. The powertrain 1 comprises a transmission housing 3 and a clutch assembly 4 arranged therein with an interlocking clutch 5 and an actuation unit 6 for actuating the clutch 5. The clutch 5 comprises a first clutch component 8 displaceable in an axial direction 7 and a second clutch component 9 which are connectable or are connected to one another interlockingly when the clutch 5 is actuated. The actuation unit 6 comprises an electromagnetic actuator 10 with a piston 11. The powertrain 1 or the actuation unit 6 comprises a system 32 for data processing. The piston 11 is displaceable from a starting position 12 to an end position 13 in order to actuate the clutch 5 and in order to displace the first clutch component 8, or is displaced when the clutch 5 is actuated. The clutch components 8, 9 can only be interlockingly connected to one another once a synchronization state has been reached. At least the piston 11 and the clutch 5 are at least partially acted upon by a transmission fluid 14. The system 32 comprises means which are suitably designed and set up for carrying out the method described, or with which the method is carried out.

[0067] The actuator 10 comprises a coil 23 to which an electrical actuating current 17 is applied to displace the piston 11. The sliding disk 18 is displaced by the piston 11 and the sensor disk 19 is displaced via the sliding disk 18. The position sensor 21 detects the position 20 of the sensor disk 19 and thus of the piston 11.

[0068] The sliding disk 18 is used to space components that rotate at different speeds. Friction between the components (otherwise, i.e., without a sliding disk) contacting one another is reduced via the sliding disk 18 so that relative rotation of the components can take place with as little loss as possible. The piston 11 contacts the sensor disk 19 via the sliding disk 18.

[0069] The sensor disk 19 interacts with the stationary position sensor 21, which is provided to detect the position 20 of the piston 11. The sensor disk 19 is connected to the piston 11, the sliding disk 18 and the first clutch component 8, so that their displacement is transmitted to the sensor disk 19. The displacement of the sensor disk 19 and thus the displacement of the piston 11 or the first clutch component 8 can be determined via the position sensor 21.

[0070] The return spring 22 is used to move the piston 11 back to the starting position 12. The return spring 22 interacts with the sensor disk 19 and is supported on a stationary component of the clutch assembly 4, for example the transmission housing 3. When the piston 11 is displaced, the return spring 22 stores the work required for the displacement and returns it to the actuation unit 6 after the actuator 10 has been actuated. This allows the piston 11 to be moved back to the starting position 12.

[0071] The cam ring is designed to form an interlocking connection, such as an interlocking connection with respect to the circumferential direction 33, with the second clutch component 9. The second clutch component 9 is connected, for conjoint rotation, to the axle 38 of the pinion gears 39 of the differential. The side bevel gears 42 of the differential are connected to the wheels of the vehicle 2 for conjoint rotation. The pinion gear 39 is rotatably arranged on the axle 38 and connected to the side bevel gears 42.

[0072] The differential cover 40 and the gearwheel 41 connecting the differential to the drive unit via the transmission are connected to one another for conjoint rotation. The first clutch component 8 is connected to the differential cover 40 for conjoint rotation.

[0073] The gearwheel 41 is connected for conjoint rotation to the axle 38 via the clutch components 8, 9.

[0074] FIG. 2 shows a graph containing several curves 25, 26, 27, 28, 29, 30, 31. A speed 16, a position 20, and a current 15, 17 are plotted on the vertical axis. The time 34 is plotted on the horizontal axis.

[0075] The method begins at a first point in time 24 with step a). A request to actuate the clutch 5 is determined here by the system 32. The system 32 of the actuation unit 6 then initiates the further steps of the method. The request to actuate the clutch 5 is aimed at establishing an interlocking connection of the clutch components 8, 9.

[0076] The first curve 25 shows the course of the electrical setpoint current when no bias current 15 is to be set. It can be seen here that a synchronization of the speeds 16, see fifth curve 29, is achieved before the setpoint current is increased from the value zero to the value of the actuating current 17 at the second time 35.

[0077] The second curve 26 shows the course of the actual electrical current that follows the theoretically required setpoint current in time and that is actually applied in clutch assembly 4.

[0078] The sixth curve 30 shows the course of the position 20 of the first clutch component 8 when no bias current 15 is set. The first clutch component 8 is actuated by the piston 11, which moves in the axial direction 7 between a starting position 12 and an end position 13 and transmits this movement to the first clutch component 8. At a fourth point in time 37, the first clutch component 8 or the piston 11 reaches its end position 13 in the axial direction 7.

[0079] The third curve 27 shows the curve of the electrical setpoint current when a bias current 15 is set. The fourth curve 28 shows the curve of the actual electrical current that follows the theoretically required target current according to the third curve 27 and that is actually applied in the clutch assembly 4.

[0080] It can be seen that step b) is initiated immediately after the first point in time 24. According to step b), the actuator 10 is energized with a bias current 15 by the system 32, wherein the piston 11 remains in the starting position 12. An electrical current required to move the piston 11, for example the actuating current 17, is therefore not set. However, the bias current 15 is as high as possible, wherein the piston 11 is not, however, intended to move. The piston 11 is held back here in the starting position 12 by the resistors present in the clutch assembly 4 or in the actuation unit 6.

[0081] According to step c), a synchronization of the speeds 16 of the clutch components 8, 9 is initiated; see fifth curve 29. Step c) takes place as a result of the detection of a request to actuate the clutch 5 according to step a), i.e., also immediately after the first point in time 24. In step c), the speeds 16 of the clutch components 8, 9 are synchronized with one another as quickly as possible. It is shown here that a rotational speed 16 of one clutch component 8, 9 is increased until a (constant) rotational speed 16 of the other clutch component 9, 8 is reached at the second point in time 35.

[0082] According to step d), the system 32 determines that the synchronization state has been reached by the clutch components 8, 9. The speeds 16 of the clutch components 8, 9 must be similar to the extent that coupling of the clutch components 8, 9 is possible, shown here by the transition of the fifth curve 29 to a constant speed 16 at the second point in time 35.

[0083] If a synchronization state is reached, the actuator 10 is energized with an actuating current 17 at the second point in time 35 in accordance with step e) (see third curve 27 and fourth curve 28 following the third curve 27), wherein the piston 11 is displaced from the starting position 12 to the end position 13. The actuating current 17 is significantly greater than the bias current 15 previously applied. The actuating current 17 overcomes the resistances in the clutch assembly 4, which are also present in step b), and displaces the piston 11 in the axial direction 7 to actuate the clutch 5.

[0084] The seventh curve 31 shows the course of the position 20 of the first clutch component 8 when a bias current 15 is set. The first clutch component 8 is actuated by the piston 11, which moves in the axial direction 7 between a starting position 12 and an end position 13 and transmits this movement to the first clutch component 8. At a fourth point in time 37, the first clutch component 8 or the piston 11 reaches its end position 13 in the axial direction 7.

[0085] The end position 13 of the piston 11 or the first clutch component 8 is now reached at a fourth point in time 37, which is significantly earlier than the third point in time 36. This can be attributed primarily to the faster establishment of the actuating current 17, which now has to be increased from the value of the bias current 15 to the value of the actuating current 17 and not from zero.

[0086] The time saving possible with the disclosed method can be seen from the distance between the fourth time 37 (end position 13detected by position sensor 21is reached when actuator 10 is supplied with bias current 15) and the third time 36 (end position 13 is reached when actuator 10 is directly supplied with actuating current 17 from a value of zero).

LIST OF REFERENCE SIGNS

[0087] 1 powertrain [0088] 2 vehicle [0089] 3 transmission housing [0090] 4 clutch assembly [0091] 5 clutch [0092] 6 actuation unit [0093] 7 axial direction [0094] 8 first clutch component [0095] 9 second clutch component [0096] 10 actuator [0097] 11 piston [0098] 12 starting position [0099] 13 end position [0100] 14 transmission fluid [0101] 15 bias current [0102] 16 speed [0103] 17 actuating current [0104] 18 sliding disk [0105] 19 sensor disk [0106] 20 position [0107] 21 position sensor [0108] 22 return spring [0109] 23 coil [0110] 24 first point in time [0111] 25 first curve (setpoint current without bias current) [0112] 26 second curve (actual current without bias current) [0113] 27 third curve (setpoint current with bias current) [0114] 28 fourth curve (actual current with bias current) [0115] 29 fifth course (speed) [0116] 30 sixth course (position of first clutch component without bias current) [0117] 31 seventh course (position of first clutch component with bias current) [0118] 32 system [0119] 33 circumferential direction [0120] 34 time [0121] 35 second point in time [0122] 36 third point in time [0123] 37 fourth point in time [0124] 38 axle [0125] 39 pinion gear [0126] 40 differential cover [0127] 41 gearwheel [0128] 42 side bevel gear