Patent EP0083490A2 successfully refreshed from Google Patents.
EP0083490A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Rotary valve for a power assisted steering mechanism
Assignee: Adwest Engineering Ltd
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Filing: 1982-12-17
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Granted: —
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Expires: 2002-12-17
Abstract
Abstract The invention provides a closed centre rotary valve and a power-assisted steering mechanism for a motor vehicle incorporating the rotary valve. The closed centre rotary valve comprises cooperating relatively rotatable sleeve and core members (1, 2) having cooperating axially-extending grooves therein and means (3) relatively biassing said members (1, 2) towards a neutral position. Said grooves comprise at least one inlet groove (4) connectable to a source of fluid under pressure, a cylinder groove (7,9) angularly spaced from said inlet groove (4) on each side thereof and connectable to opposite sides of double-acting piston-and-cylinder means, and a return groove (11) in overlapping relation with each of said cylinder grooves (7, 9) in the neutral position of the valve and connectable to a reservoir for the fluid under pressure, said inlet groove (4) being closed from communication with the cylinder and return grooves (7, 9,11) in the neutral position of the valve. The arrangement is such that on relative angular displacement of said member (1, 2) in either direction from the neutral position the inlet groove (4) is placed in communication with one of said cylinder grooves (7, 9), said one cylinder groove and its associated return groove (11) move out of their overlapping relation to close communication therebetween, and the overlap between the other cylinder groove and its associated return groove (11) is increased.
Inventors
- 👤 Barry John Millard
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 19:14
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/08; B62D5/083; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86638; Y10T137/86646; Y10T137/86662
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
203 words
A closed centre rotary valve comprising cooperating relatively rotatable sleeve and core members (1,2) haying cooperating axially-extending grooves therein and means (3) relatively biassing said members (1,2) towards a neutral position, -characterised in that said grooves comprise at least one inlet groove (4) connectable to a source of fluid under pressure, a cylinder groove (7,9) angularly spaced from said inlet groove (4) on each side thereof and connectable to opposite sides of double-acting piston-and-cylinder means, and a return groove (11) in overlapping relation with each of said cylinder grooves (7,9) in the neutral position of the valve and connectable to a reservoir for the fluid under pressure, said inlet groove (4) being closed from communication with the cylinder and return grooves (7,9,11) in the neutral position of the valve, the arrangement being such that on relative angular displacement of said members (1,2) in either direction from the neutral position the inlet groove (4) will be placed in communication with one of said cylinder grooves (7,9), said one cylinder groove and its associated return groove (11) will move out of their overlapping relation to close communication therebetween, and the overlap between the other cylinder groove and its associated return groove (11) will be increased.
Claim 2
Dependent Claim
203 words
A closed centre rotary valve comprising cooperating relatively rotatable sleeve and core members (1,2) haying cooperating axially-extending grooves therein and means (3) relatively biassing said members (1,2) towards a neutral position, -characterised in that said grooves comprise at least one inlet groove (4) connectable to a source of fluid under pressure, a cylinder groove (7,9) angularly spaced from said inlet groove (4) on each side thereof and connectable to opposite sides of double-acting piston-and-cylinder means, and a return groove (11) in overlapping relation with each of said cylinder grooves (7,9) in the neutral position of the valve and connectable to a reservoir for the fluid under pressure, said inlet groove (4) being closed from communication with the cylinder and return grooves (7,9,11) in the neutral position of the valve, the arrangement being such that on relative angular displacement of said members (1,2) in either direction from the neutral position the inlet groove (4) will be placed in communication with one of said cylinder grooves (7,9), said one cylinder groove and its associated return groove (11) will move out of their overlapping relation to close communication therebetween, and the overlap between the other cylinder groove and its associated return groove (11) will be increased.
Claim 3
Dependent Claim
29 words
A rotary valve according to claim 1, characterised in that said grooves further comprise transfer grooves (14,15) between the inlet groove (4) and said cylinder grooves (7, 9) .
Claim 4
Dependent Claim
89 words
A rotary valve according to claim 2, characterised in that stop means is provided for limiting the degree of relative angular movement between said members (1,2) and two transfer grooves (14,15) are provided between the inlet groove (4) and each cylinder groove (7,9), said transfer grooves (14,15) overlapping one another to such an extent that there will be communication therebetween in all relative angular positions of said members (1,2) and one of said transfer grooves (15) overlapping its adjacent cylinder groove (7,9) in the neutral position of the valve.
Claim 5
Dependent Claim
46 words
A rotary valve according to claim 1, 2 or 3, characterised in that the inlet groove (4) is provided in one of said members (1,2) and is closed by a land (6) of the other of said members (1,2) in the neutral position of the valve.
Claim 6
Dependent Claim
48 words
A rotary valve according to any one of the preceding claims, characterised in that said biassing means comprises a torsion bar (3) one end of which is secured to one of said members (1,2) and the other end of which is secured to the other of said members.
Claim 7
Dependent Claim
103 words
A rotary valve according to claim 3, characterised in that the inlet groove (4), return grooves (11) and transfer grooves (15) are in the core member (2), the cylinder grooves (7,9) and the transfer grooves (14) are in the sleeve member (1), the inlet groove (4) is closed by a land (6) of the sleeve member (1) in the neutral position of the valve, and the core member (2) has a hollow centre (13) which is connectable to said reservoir for the fluid under pressure and which is connected to the return grooves (11) by radial passages (12) in the core member (2).
Claim 8
Dependent Claim
130 words
A rotary valve according to claim 3 or 6, characterised in that a plurality of inlet grooves (4) are provided each with its associated cylinder grooves (7,9), transfer grooves (14,15) and return grooves (11) and each return groove (11), in the neutral position of the members (1,2), is in overlapping relation with a first cylinder groove (7 or 9) associated with a first inlet groove (4) and a second cylinder groove (9 or 7) associated with a second inlet groove (4) whereby on relative angular displacement of said members (1,2) communication will be closed between each return groove (11) and one of said first and second cylinder grooves (7,9) and communication will be increased between each return groove (11) and the other of said first and second cylinder grooves (7,9).
Claim 9
Dependent Claim
76 words
A rotary valve according to any one of the preceding claims, characterised in that the core member (2) is rotatable relative to the sleeve member (1) and that hydraulic reaction pistons (44) slidable in cylinders (43) the opposite ends of which can be subjected to the cylinder pressures on either side of a said double-acting piston-and-cylinder means are connected to the core member (2) for providing a hydraulic reaction to rotary movement of the core member.(2).
Claim 10
Dependent Claim
25 words
9, A power-assisted steering mechanism for a motor vehicle when provided with a closed centre rotary valve according to any one of the preceding claims.
Claim 11
Dependent Claim
91 words
A power-assisted steering mechanism according to claim 9, characterised in that the steering mechanism is a rack-and-pinion steering mechanism comprising a toothed rack (21) connected at each end of its ends to a piston rod (23) carrying a piston (24) slidable in a cylinder (25) and a pinion (29) in meshing engagement with the toothed rack (21), the pinion (29) being fixedly secured to the sleeve member (1) of the rotary valve for rotary movement therewith and the core member (2) being connectable to the steering control of a motor vehicle.
References Cited (Backward Citations)
No citation records indexed.
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