Hydraulic circuit for oil supply of an automatic, particularly a stepped automatic transmission for motor vehicles

• US 20050263352A1
• Filed: 05/25/2005
• Published: 12/01/2005
• Est. Priority Date: 05/26/2004
• Status: Abandoned Application

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Gethofer, Frank, Fideler, Winfried
• Application Number:
  US11/137,719
• Publication Number:
  US 20050263352A1
• Time in Patent Office: Days
• US Class Current: 184/6.100
• CPC Class Codes: F16H 57/0434 relating to lubrication supply, e.g. pumps arrangement of pumps F16H57/0441; Pressure control grooves with pumping effect for supplying lubricant F16H57/0428; generation and variation of line pressure for transmission control F16H61/0021
• CPC Class Codes: F16H 61/0021 Generation or control of line pressure
• CPC Class Codes: F16H 61/0025 Supply of control fluid; Pumps therefore
• CPC Class Codes: F16H 61/0031 using auxiliary pumps, e.g. pump driven by a different power source than the engine

Abstract

The invention concerns a hydraulic circuit (3) for oil supply of an automatic transmission, in particular a stepped automatic transmission for motor vehicles, consisting of a low pressure circuit (4) for delivering a first volume stream V1 at a first pressure level P1 and a high pressure circuit (5) for delivering a second volume stream V2 at a second, higher pressure P2.

It is proposed that when necessary the first pressure level P1 of the first volume stream V1 can be modulated to the higher pressure P2 and the two volume streams V1, V2 can be summed at the same pressure level P2.

Claims

1. Hydraulic circuit (3, 12) for oil supply of an automatic transmission, in particular a stepped automatic transmission for motor vehicles, consisting of a low-pressure circuit (4) for delivering a first volume stream V1 at a first pressure level P1 and a high pressure circuit (5) for delivering a second volume stream V2 at a second higher pressure P2, such that the first pressure level P1 of the first volume stream V1 can, when necessary, be modulated to the higher pressure level P2 and the two volume streams V1 and V2 can be summed at the same pressure level P2.

2. Hydraulic circuit according to claim 1, characterized in that the summing of the volume streams V1, V2 takes place when a gearshift is initiated in the stepped automatic transmission.

3. Hydraulic circuit according to claims 1 or 2, characterized in that a pressure-relief valve (8) is associated with the high pressure circuit (5) to maintain the pressure level P2.

4. Hydraulic circuit according to claims 1, 2 or 3, characterized in that a pressure-relief valve (9) is associated with the low pressure circuit (4) to maintain the pressure level P1.

5. Hydraulic circuit according to claim 4, characterized in that the pressure-relief valve (9) can be adjusted by a pressure regulator to change the pressure level P1, in particular to increase it to the pressure level P2.

6. Hydraulic circuit according to any of claims 1 to 5, characterized in that a first delivery element (6) is associated with the low pressure circuit (4) to deliver the first volume stream V1 and a second delivery element (7) is associated with the high pressure circuit to deliver the second volume stream V2.

7. Hydraulic circuit (3) according to any of claims 1 to 6, characterized in that a one-way valve (11) opening towards the high pressure circuit (5) is arranged between the high pressure circuit (5) and the low pressure circuit (4).

8. Hydraulic circuit (12) according to any of claims 1 to 6, characterized in that the two volume streams V1, V2 can be summed by means of a switching variable-path valve (14).

9. Hydraulic circuit (12) according to claim 8, characterized in that the variable-path valve (14) has two positions (14a, 14b), namely a first position (14a) in which the two volume streams V1, V2 are separated and a second position (14b) in which the two volume streams V1, V2 are combined.

10. Hydraulic circuit according to claim 6, characterized in that the two delivery elements (6, 7) form a tandem pump.

11. Hydraulic circuit according to claim 6, characterized in that the first delivery element (6) is formed as an electrically driven pump and the second delivery element (7) is formed as a mechanically driven pump, in particular driven by the pump impeller of the stepped automatic transmission.

12. Hydraulic circuit according to claim 6, characterized in that the two delivery elements (6, 7) are formed as a dual-circuit pump.

13. Hydraulic circuit according to claims 6, 10 or 12, characterized in that the delivery elements (6, 7) are formed as gear-type, radial piston or vane cell pumps.