Power assisted steering system, in particular, for motor vehicles
First Claim
1. Power assisted steering system, especially for motor vehicles, which comprises a servomotor (2) provided with working chambers;
- a servopump (3) fluidly connected to the servomotor (2) via a control valve (1) and also fluidly connected to a tank (4);
wherein the control valve (1) is a four-way valve having a supply connection (6;
22,
23), a feedback connection (7) and two working connections (8,
10) having lines (11,
12), respectively, each of said lines (11, 127 leading to the working chambers of said servomotor (2), said control valve (1) also including a controllable feedback device (5) connected between the servopump (3) and the supply connection (6;
22,
23) and a control member (46) for controlling the feedback device (5) and having a choke cross-section which varies as a function of vehicle speed; and
a device (13) for piling up the pressure medium stream located between the feedback device (5) and the supply connection (6;
22,
23).
1 Assignment
0 Petitions
Accused Products
Abstract
A power assisted steering system, in particular, for motor vehicles, contains a servomotor (2), a servopump (3), a tank (4), a control valve (1) with a controllable feedback device (5), and a control member (46) whose choke cross section can be altered as a function of the vehicle speed. Control valve (1) is made as a four-way valve and has a supply connection (22, 23), a feedback connection (7), and two working connections (8, 10) for the lines (11, 12) that lead to the two working chambers of servomotor (2). Between feedback device (5) and supply connection (22, 23), there is arranged a device (13) for piling up the pressure medium stream and the device is made according to one practical example as a choke (50, 51). With the help of this choke (50, 51), one can achieve a hydraulic centering component in addition to a mechanical centering component.
16 Citations
7 Claims
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1. Power assisted steering system, especially for motor vehicles, which comprises a servomotor (2) provided with working chambers;
- a servopump (3) fluidly connected to the servomotor (2) via a control valve (1) and also fluidly connected to a tank (4);
wherein the control valve (1) is a four-way valve having a supply connection (6;
22,
23), a feedback connection (7) and two working connections (8,
10) having lines (11,
12), respectively, each of said lines (11, 127 leading to the working chambers of said servomotor (2), said control valve (1) also including a controllable feedback device (5) connected between the servopump (3) and the supply connection (6;
22,
23) and a control member (46) for controlling the feedback device (5) and having a choke cross-section which varies as a function of vehicle speed; and
a device (13) for piling up the pressure medium stream located between the feedback device (5) and the supply connection (6;
22,
23). - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a servopump (3) fluidly connected to the servomotor (2) via a control valve (1) and also fluidly connected to a tank (4);
Specification
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- Resources
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Current AssigneeZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
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Original AssigneeZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
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InventorsLang, Armin
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Primary Examiner(s)Boehler, Anne Marie
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Assistant Examiner(s)ZEENDER, FLORIAN M
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Application NumberUS08/374,689Time in Patent Office686 DaysField of Search180/132, 180/141, 180/143, 180/DIG. 6, 180/DIG. 8, 180/DIG. 16, 180/403, 180/410, 180/414, 180/417, 180/421, 180/423, 180/441, 180/442US Class Current180/423CPC Class CodesB62D 5/08 characterised by type of st...B62D 6/02 responsive only to vehicle ...
