AUTOMATED TRANSMISSION AND METHOD FOR OPERATING AN AUTOMATED TRANSMISSION

• US 20120144940A1
• Filed: 06/28/2010
• Published: 06/14/2012
• Est. Priority Date: 06/26/2009
• Status: Active Grant

• Current Assignee: Getrag Ford Transmissions GmbH
• Original Assignee: Getrag Ford Transmissions GmbH
• Inventors: Moehlmann, Reinhard
• Granted Patent: US 9,068,648 B2
• Time in Patent Office: Days
• US Class Current: 74/331
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: F16H 61/688 with two inputs, e.g. selection of one of two torque-flow paths by clutches
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts
• CPC Class Codes: Y10T 74/19251 Control mechanism

Abstract

An automated transmission comprises a hydraulic control device and one or more hydraulically actuated gear units. The hydraulic control device comprises a control unit for setting actuating pressures on the gear units; a base pressure control valve for adjusting a hydraulic base pressure of the hydraulic control device; and a device for controlling the base pressure control valve dependent on the actuating pressures. The automated transmission further comprises a device for switching through an actuating hydraulic pressure to the base pressure control valve. A method comprises the method steps of adjusting a hydraulic base pressure at the hydraulic control device; adjusting actuating pressures for actuating one or more transmission units; switching through one of the actuating pressures to the base pressure control valve; and adjusting the hydraulic base pressure by one of the actuating pressures.

Claims

1. An automated transmission comprising:

a hydraulic control device; and

one or more hydraulically actuated gear units, wherein the hydraulic control device comprises;

a control unit for setting actuating pressures on the gear unit;

a base pressure control valve for adjusting a hydraulic base pressure of the hydraulic control device; and

,

a device for controlling the base pressure control valve dependent on the actuating pressures; and

wherein

the automated transmission further comprises a device for switching through an actuating hydraulic pressure to the base pressure control valve.

2. The transmission of claim 1, wherein the device for controlling the base pressure control valve dependent on the actuating pressures is adapted to adjust the base pressure is adjustable at least temporarily by the hydraulic control device to assume a lower actuating pressure.

3. The transmission according to claim 1, wherein the transmission is designed as a dual clutch transmission comprising as hydraulically actuated gear units a first clutch for connecting and disconnecting a first partial transmission to or from a powertrain, a second clutch for connecting and disconnecting a second partial transmission to or from the powertrain, and a switching system or shifting gears in the first and second partial transmission.

4. The transmission of claim 1, further comprising a device for determining a highest temporarily required actuating pressure at least at one of the transmission units, the two clutches and the switching system.

5. The transmission of claim 1, wherein the device for controlling the base pressure control valve dependent on an actuating pressure comprises a plurality of devices for determining a highest temporarily required actuating pressure.

6. The transmission of claim 1, wherein a plurality of devices for determining the highest temporarily required actuating pressure are connected in a cascade fashion.

7. The transmission of claim 1, wherein the device for controlling the base pressure control valve dependent on the actuating pressures is adapted to adjust the hydraulic base pressure is adjustable to be by an amount delta higher than the highest temporarily required actuating pressure.

8. The transmission of claim 1, wherein the device or controlling the base pressure control valve dependent on an actuating pressure comprises at least one shuttle valve that is a double-ball check-valve.

9. The transmission of claim 8, further comprising a device for the shuttle valve, said device separating the transmission units hydraulically from each other at any actuating pressures.

10. The transmission of claim 1, wherein the control unit comprises a hydraulic pilot control device for the base pressure control valve.

11. The transmission of claim 1, wherein the control unit comprises a first pressure control valve and at least one further pressure control valve, wherein by the first pressure control valve an actuating pressure for the first clutch is adjustable and by the further pressure control valve a further actuating pressure for the second clutch or for the switching system is adjustable.

12. The transmission of claim 11, wherein the pressure control valves for adjusting the respective actuating pressure each have a pilot valve for controlling the base pressure control valve dependent on an actuating pressure.

13. The transmission of claim 1, further comprising a device for hydraulically connecting said device for controlling the base pressure control valve dependent on an actuating pressure both with output-side hydraulic lines of the control unit and with the base pressure control valve.

14. The transmission of claim 1, wherein hydraulic apertures are provided within a hydraulic line system of the hydraulic control device.

15. The transmission of claim 1, wherein switching valves are provided between the hydraulic clutches and the pressure control valves at a position upstream of the hydraulic clutches.

16. The transmission of claim 3, wherein a temporarily required actuating pressure for actuating the switching system is always higher than one of the two actuating pressures of the clutches.

17. A method for operating an automated transmission comprising:

a hydraulic control device; and

one or more hydraulically actuated gear units, wherein the hydraulic control device comprises;

a control unit for setting actuating pressures on the gear units;

a base pressure control valve for adjusting a hydraulic base pressure of the hydraulic control device; and

a device for controlling the base pressure control valve dependent on the actuating pressures; and

wherein the automated transmission further comprises a device for switching through an actuating hydraulic pressure to the base pressure control valve;

said method comprising;

adjusting by the base pressure control valve a hydraulic base pressure is adjusted at the hydraulic control device; and

adjusting by suitable pressure control valves actuating pressures for actuating one or more transmission units;

switching through one of the actuating pressures to the base pressure control valve; and

adjusting the hydraulic base pressure by one of the actuating pressures.

18. The method of claim 17, further comprising adjusting the base pressure at least temporarily to a lower actuating pressure.

19. The method of claim 17, further comprising adjusting the hydraulic base pressure by the highest temporarily required actuating pressure.

20. The method of claim 17, further comprising controlling the base pressure control valve by one of the actuating pressures.

21. The method of claim 17, further comprising generating an actuating pressure-dependent control signal for controlling the base pressure control valve, said control signal representing a pressure at the output side of one of the pressure control valves that are adjusting the actuating pressures.