DRIVE TRAIN HAVING CLUTCH ACTIVATION FOR OVERCOMING THE BACKLASH OF THE DRIVE TRAIN BEFORE START-UP

• US 20120160046A1
• Filed: 12/20/2011
• Published: 06/28/2012
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: Schaeffler Technologies AG & Co.KG (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Schaeffler Technologies GmbH & Co. KG (INA-Holding Schaeffler GmbH & Co. KG)
• Inventors: Reuschel, Michael
• Granted Patent: US 8,584,545 B2
• Time in Patent Office: Days
• US Class Current: 74/409
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/1045 Friction clutch
• CPC Class Codes: F16D 2500/3067 Speed of the engine
• CPC Class Codes: F16D 2500/30816 Speed of the input shaft
• CPC Class Codes: F16D 2500/30825 Speed of the output shaft
• CPC Class Codes: F16D 2500/50623 Preventing transmission load change
• CPC Class Codes: F16D 48/08 Regulating clutch take-up on starting
• CPC Class Codes: F16H 2312/022 Preparing to drive off
• CPC Class Codes: F16H 61/68 specially adapted for stepped gearings
• CPC Class Codes: Y10T 74/19623 Backlash take-up

Abstract

A drive train for a motor vehicle, including a drive unit having a drive shaft and a transmission having a transmission input shaft and a plurality of gears, of which at least one is used as a starting gear for the motor vehicle, and having a friction clutch, which is arranged between the crankshaft and the transmission input shaft and is actuated in an automated manner. In order to prevent start-up noise caused by backlashes in the motor vehicle, a backlash present in the transmission is compensated by applying a small compensating torque set at the friction clutch to the transmission input shaft while the starting gear is engaged before start up.

Claims

1. A drive train for a motor vehicle, comprising a drive unit having:

a drive shaft; and

,

a transmission having a transmission input shaft and a plurality of gears, of which at least one is used as a starting gear for the motor vehicle, and having a friction clutch, which is arranged between the crankshaft and the transmission input shaft and is actuated in an automated manner, wherein a backlash present in the transmission is compensated by applying a small compensating torque set at the friction clutch to the transmission input shaft while the starting gear is engaged before start up.

2. The drive train according to claim 1, wherein the compensation torque is smaller than a startup torque required for moving the motor vehicle.

3. The drive train according to claim 1, wherein the compensation torque required for compensating the rotation clearance is learned during operations of the drive train.

4. The drive train according to claim 3, wherein the learned compensation torque is continuously updated.

5. The drive train according to claim 3, wherein the compensation torque is learned during pull/push phases of the drive train.

6. The drive train according to claim 5, wherein the speed of the transmission input shaft is determined during a pull/push phase and processed for learning the compensation torque.

7. The drive train according to claim 5, wherein the speed of the drive shaft is determined during a pull/push-phase with a completely closed friction clutch and processed for learning the compensation torque.

8. The drive train according to claim 6, wherein the rotation clearance is determined by comparing one of the speeds with a speed of a transmission output shaft.

9. The drive train according to claim 8, wherein a respective compensation torque is associated with the determined rotation clearance.

10. The drive train according to claim 1, wherein plural startup methods are usable and the compensation torque is configured as a function of the startup gear used.

11. The drive train according to claim 1, wherein the compensation clearance is compensated when the motor vehicle is standing still and a brake of the motor vehicle is actuated.

12. A method for actuating a drive train for a motor vehicle including a drive unit having a drive shaft and a transmission having a transmission input shaft and a plurality of gears, of which at least one is used as a starting gear for the motor vehicle, and having a friction clutch, which is arranged between the crankshaft and the transmission input shaft and is actuated in an automated manner, the method comprising compensating a backlash present in the transmission by applying a small compensating torque set at the friction clutch to the transmission input shaft while the starting gear is engaged before start up.