Hydraulic transmission control
AssigneeZF Friedrichshafen AG
InventorsGeorg Gierer, Thilo Schmidt, Christian Popp
Life of this patent
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Abstract
A hydraulic transmission unit comprises at least one pressure regulation valve (1) and a pilot control valve (2) which is connected to the pressure regulation valve (1) by a pilot control line (35). A pre-filling valve (3, 303) sets a pre-filling pressure (p—3) to avoid draining of a clutch (20) and the lines (231, 331) connected to the clutch (20) in an operating condition in which the clutch (20) is not actuated. To avoid draining when the clutch when in the operating condition, the pilot control line (35) is also connected to at least one line (236, 238, 336, 338) which is pressurized with a second pre-filling pressure (p—3).
Claims14
A hydraulic transmission control unit comprising:
- at least one pressure regulation valve (1) and at least one pilot control valve (2) which is connected, via a pilot control line (35), to the at least one pressure regulation valve (1);
- a pre-filling valve (3, 303) for adjusting a first pre-filling pressure (p_3) to prevent draining of a clutch (20) and pressure lines (231, 331) connected to the pre-filling valve (3, 303) when the clutch (20) is not-actuated;
- and
- the pilot control line (35) being connected to at least one other line (236′, 238, 336, 338) which is under a second pre-filling pressure (p_3′) such that draining of the pilot control line (35), when the clutch (20) is not actuated, is prevented.
A hydraulic transmission control unit in combination with a transmission for a motor vehicle, the transmission control unit comprising:
- at least one pressure regulation valve (1) and at least one pilot control valve (2) which is connected, via a pilot control line (35), to the at least one pressure regulation valve (1);
- a pre-filling valve (3, 303) for adjusting a first pre-filling pressure (p_3) to prevent draining of a clutch (20) and pressure lines (231, 331) connected to the pre-filling valve (3, 303) when the clutch (20) is not-actuated;
- and
- the pilot control line (35) being connected to at least one other line (236′, 238, 336, 338) which is under a second pre-filling pressure (p_3′) such that draining of the pilot control line (35) when the clutch (20) is not actuated is prevented.
Dependencies are inferred from the claim text.