Apparatus for compensating viscous characteristics of hydraulic fluid in a hydraulic pressure line

• US 20040222319A1
• Filed: 04/29/2004
• Published: 11/11/2004
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Schiele, Peter, Schmidt, Thilo, Gierer, Georg
• Granted Patent: US 7,258,640 B2
• Time in Patent Office: Days
• US Class Current: 239/501
• CPC Class Codes: F15B 21/045 Compensating for variations in viscosity or temperature

Abstract

An apparatus for compensating the viscous characteristics of a hydraulic medium in a pressure line (10) in which apparatus a pressure nozzle (12) with constant geometry and constant through-flow cross-section is located in the pressure line (10). It is provided according to the invention that in the pressure Line (10) upstream or downstream of the pressure nozzle (12) at least one channel-shaped area (11, 28) is made or situated which, compared to the pressure nozzle (12), has a smaller through-flow cross-section and a larger axial extension and that the control pressure (P_SekV) abutting between the channel-shaped area (11, 28) and the pressure nozzle (12) can be supplied via a control pressure line (13) to a shift valve (14).

Claims

1-18. -18. (CANCELED).

19. An apparatus for compensating the viscous characteristics of a hydraulic medium in a pressure line (10), the pressure line (10) having a first pressure nozzle (12) of constant geometry and a constant through-flow cross-section, wherein at least one channel-shaped area (11, 28) is made or situated inside the pressure line (10), upstream or downstream of said pressure nozzle (12), which in comparison to the first pressure nozzle (12) the at least one channel-shaped area (11, 28) has a smaller through-flow cross-section and a larger axial extension, and a control pressure (P_SekV) abutting between the channel-shaped area (11, 28) and the first pressure nozzle (12) is supplied to a shift valve (14) via a control pressure line (13).

20. The apparatus according to claim 19, wherein the channel-shaped area (11, 28) is situated between the first pressure nozzle (12) and a second pressure nozzle (7).

21. The apparatus according to claim 19, wherein the channel-shaped area (11) is designed as control line member.

22. The apparatus according to claim 19, wherein said channel-shaped area (11) is designed as at least one spiral duct (28) on the outer periphery of a pressure nozzle (27).

23. The apparatus according to claim 19, wherein said channel-shaped area (11) is designed as at least one elongated duct (28) on the outer periphery of a pressure nozzle (27).

24. The apparatus according to claim 19, wherein said channel-shaped area (11) is designed as at least one elongated aperture in a pressure nozzle (27).

25. The apparatus according to claim 21, wherein said pressure nozzle (27) is cylindrically designed.

26. The apparatus according to claim 25, wherein said cylindrical pressure nozzle (27) is situated in a housing (20) with an upstream inlet aperture (21) and a downstream outlet aperture (22), a through-flow cross-section of the inlet and outlet apertures (21;

22) being smaller than an inner diameter of the housing interior (29).

27. The apparatus according to claim 25, wherein said pressure nozzle housing (20) has one hollow cylindrical section (23) and one cap (24) shutting said section (23).

28. The apparatus according to claim 25, wherein one cylindrical pressure nozzle (27) is inserted into a pressure nozzle housing (20), on two front side ends of the cylindrical-pressure nozzle (27) one respective pivot (25;

26) is made whose front side surfaces (30;

31) rest on an inner side of the cap (24) and of the housing bottom.

29. The apparatus according to claim 19, wherein said channel-shaped area (11, 28) in a hydraulic transmission control apparatus has a length of from 60 mm to 120 mm, preferably of from 60 mm to 100 mm and most preferably of from 80 mm to 90 mm while the pressure nozzles (7;

12) have an axial length of from 0.4 mm to 1.6 mm, preferably of from 0.6 to 14 mm and most preferably of from 0.8 mm to 1.2 mm.

30. The apparatus according to claim 19, wherein the channel-shaped area (11, 28) in a hydraulic transmission control apparatus has a passage diameter of from 0.5 mm to 1.5 mm, preferably of from 0.6 mm to 1.2 mm and most preferably of from 0.7 mm to 0.9 mm while the first and second pressure nozzles (7;

12) have a passage diameter of from 0.4 mm to 1.6 mm, preferably from 0.7 mm to 1.4 mm and most preferably of from 1.1 mm to 1.3 mm.

31. The apparatus according to claim 19, wherein the apparatus is situated between a main pressure valve (4) and the shift valve (14).

32. The apparatus according to claim 19, wherein the apparatus is made in a hydraulic slide valve casing of an automatic transmission.

33. The apparatus according to claim 19, wherein via said shift valve (14) can be supplied with a control pressure those shift element(s) (clutches and/or brakes) of an automatic transmission with which a predetermined transmission reduction ratio can be activated or deactivated.

34. The apparatus according to claim 33, wherein in case of a drop of the viscosity-compensated control pressure (P_SekV) abutting in the pressure line (13) below a minimum value dependent on the engine rotational speed, the automatic transmission can be shifted to an idling state by means of the shift valve (14).

35. The apparatus according to claim 19, wherein the channel-shaped area (11, 28) and the first pressure nozzle (12) are designed as one integrated part, that the part has between the channel-shaped area and the area of the first pressure nozzle (12) one aperture for branching off of the control pressure (P_SekV) abutting there to the pressure line (13) leading to the shift valve (14) or one such aperture is associated with this place and that the part can be inserted in a control pressure line (10).

36. The apparatus according to claim 19, wherein the channel-shaped area (11, 28) is disposed or made upstream or downstream of the first pressure nozzle (12), the same as upstream or downstream of the branching off for the pressure line (13) leading to the shift valve (14).