Servo assistance device for motor vehicle variable-speed transmission
AssigneeZF Friedrichshafen AG
InventorsDieter Fischer, Klaus Spath
Life of this patent
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Abstract
A servo-assistance device (10) for a shift mechanism of a motor vehicle transmission, with which a characteristic curve can be produced which, as a function of a manual shifting force or a shift phase, has ranges of different gradients or proportionality to the manual shifting force. The servo-assistance device (10) includes an element (20) which is acted upon by the manual shifting force to be assisted. To produce the characteristic curve, the servo-assistance device (10) has components (42, 44, 50, 52) that are actuated by a servo-pressure (60) in such manner that the element (20) maintains its current position.
Claims15
A servo-assistance device (10) for a shift mechanism of a motor vehicle transmission, with which a characteristic curve is produced which, as a function of either a manual shifting force or a shift phase, comprises ranges of different gradients or proportionality to the manual shifting force, the servo-assistance device (10) comprising an element (20) upon which the manual shifting force to be assisted acts,
- wherein the servo-assistance device (10) comprises a valve (56) with valve pistons (40, 48), and
- means (42, 44, 50, 52) upon which a servo-pressure (60) acts such that the servo-pressure (60) acts upon one of the valve pistons (40, 48) to produce a first range of the characteristic curve and, beyond a specifiable servo-pressure (60), the means (42, 44, 50, 52) co-operates with the valve pistons (40, 48) such that a second range of the characteristic curve is produced, whose gradient is smaller than a gradient of the first range of the characteristic, in such manner that the element (20) maintains its current position.
A method of producing a characteristic curve of a servo-assistance device (10) for a shift mechanism of a motor vehicle transmission, such that the characteristic curve has ranges with either different gradients or proportions to a manual shifting force as a function of either the manual shifting force or a shift phase, and the servo-assistance device (10) comprises an element (20) acted upon by the manual shifting force to be assisted,
- wherein a valve (56) with valve pistons (40, 48) and means (42, 44, 50, 52) are provided in the servo-assistance device (10), upon which a servo-pressure (69) acts, such that a first range of the characteristic curve is produced when a servo-pressure (60) acts on one of the valve pistons (40, 48) and, beyond a specifiable servo-pressure (60), the means (42, 44, 50, 52) are actuated and co-operate with the valve pistons (40, 48) such that a second range of the characteristic curve is produced, and has a gradient smaller than a gradient of the first range of the characteristic curve.
Dependencies are inferred from the claim text.