Auxilliary power steering, especially for motor vehicles

Claim 2

A power-steering mechanism comprising a housing (3) having a cylinder and a double-acting pressure piston (7) therein with a pressure chamber (8, 9) at each end of the piston; a nut (13) rotatably mounted within the piston and a steering shaft worm (2) extending into the piston and having driving coaction with the nut; a valve actuator (14) carried by the nut and being disposed within the piston, wherein initial rotation of said worm in a steering movement effects rotation of said nut and rotative motion of said valve actuator about the worm axis; a control valve (17) carried by the piston and being engaged for reversible movement by said valve actuator; pressure fluid passage means in said control valve, said piston, and said housing for conducting fluid to either chamber to pressurize an end of said piston responsive to movement in a respective direction of said control valve.

Claim 3

A mechanism as set forth in claim 1, wherein said control valve (17) comprises a valve spool (22) slideably carried in said piston in a bore transverse of and offset from the axis thereof.

Claim 4

A mechanism as set forth in claim 1, said valve actuator (14) comprising an elongated member disposed at one side of the axis of said piston and generally parallel to the axis of said piston; said piston having rack teeth extending along an opposite side; a gear sector for a steering mechanism in said housing meshing with said rack.

Claim 5

A mechanism as set forth in claim 1, said control valve (17) comprising a valve spool (22) having a bore and said valve actuator (14) having a finger (15) extending into said bore; a bore in said piston offset from and generally transverse of the axis thereof, and said control valve being carried in said bore of said piston; said valve actuator being an elongated member extending generally parallel to the piston axis; said piston having a wall with an aperture (16) through which said valve actuator passes and said aperture being of predetermined diameter larger than the portion of the valve actuator passing therethrough whereby edges thereof serve as a limit of motion in either direction for said valve actuator for controlling the limit of movement of said control valve.

Claim 6

A mechanism as set forth in claim 1, including a centering device (45) for said valve actuator (14); spring means (47) in prestressed condition disposed to act on said nut, said actuator and said control valve to effect an initial neutral position; and adjusting means (51, 52) at opposite ends of said spring means and being adjustable to increase or decrease spring bias reacting against respective adjusting means; wherein said adjusting means is carried on said piston so that said spring means can effect force against said adjusting means to rotationally center said nut and thus said valve actuator and control valve relative to a predetermined position.

Claim 7

A power-steering mechanism as set forth in claim 1, said piston (7) having a pair of longitudinal grooves (55, 56) for receiving pressure fluid from a source; said grooves being connected with each other by transverse bores (57, 58) in said piston; said control valve (17) being in a bore of said piston and said bore being open at both ends; said control valve comprising flow passages and comprising a valve spool (22) reciprocal in said bore by said valve actuator (14); said open ends of said bore communicating with a respective longitudinal groove (55, 56) for entry of pressure fluid into said control valve at both ends of said valve spool; said piston having a third longitudinal groove (61); certain of said passage means being in said housing for continuously connecting said piston grooves for pressure fluid and exhaust flow outside said housing and for flow connection to said valve spool; said valve spool having certain of said passage means to eFfect selective flow communication upon reciprocation of said valve spool for flow to and from said pressure chambers (8, 9).

Claim 8

A power-steering mechanism as set forth in claim 1, said piston (7) having a pair of longitudinal grooves (55, 56) for receiving pressure fluid from a source; said grooves being connected with each other by transverse bores (57, 58) in said piston; said control valve (17) being in a bore of said piston and said bore being open at both ends; said control valve comprising flow passages and comprising a valve spool (22) reciprocal in said bore by said valve actuator (14) said open ends of said bore communicating with a respective longitudinal groove (55, 56) for entry of pressure fluid into said control valve at both ends of said valve spool; said piston having a third longitudinal groove (61); certain of said passage means being in said housing for continuously connecting said grooves for pressure fluid and exhaust flow outside said housing and for flow connection to said valve spool; said valve spool having certain of said passage means to effect selective flow communication upon reciprocation of said valve spool for flow to and from said pressure chambers (8, 9); including seals (55'', 56'', 61'') at the surface of said piston surrounding said grooves and coacting with said cylinder to seal said grooves; said housing passage means having an inlet port (60) communicating pressure fluid at all times to said first mentioned grooves (55, 56) and also having an outlet port (62) communicating at all times with said third groove (61).

Claim 9

A power-steering mechanism as set forth in claim 1, including a pair of reaction pistons (30, 31); said control valve (17) comprising a valve spool (22) and said reaction pistons being disposed in respective reaction piston chambers at the ends of said valve spool and having exterior ends secured to said piston; a bore in said piston carrying said control valve; said passage means comprising valve passages in said control valve (17) for connecting said reaction piston chambers to inlet and outlet pressure passages comprised in said passage means whereby said reaction pistons are thus subjected to inlet or outlet pressure depending upon direction of turn, for imparting simulated steering resistance.

Claim 10

A power-steering mechanism as set forth in claim 1, said piston having a blind bore and said worm (102) being disposed in said blind bore, the piston end of said worm having a bearing (106) effecting a slideable sleeve support and rotational support within said blind bore.

Claim 11

A power-steering mechanism as set forth in claim 1, said control valve comprising a valve sleeve (27) and a valve spool (22) therein, said piston having a bore in which said valve sleeve is fixed, said sleeve and spool being provided with coacting grooves for directional pressure fluid flow control dependent upon direction of movement of said valve spool and perforate guide means (26) within opposed portions of said spool and sleeve to insure alignment during relative motion therebetween.

Claim 12

A power-steering mechanism as set forth in claim 1, including a portion of a steering shaft (1) passing through one (9) of said pressure chambers (8, 9) and means for sealing said portion against pressure in said chamber comprising a sleeve (70) carried by said housing (3) and encompassing said portion and extending into said piston (7) and sealing means (74, 75) surrounding said sleeve to seal the exterior thereof at said piston and at said housing.

Claim 13

A power-steering mechanism as set forth in claim 1, said housing having a steering gear shaft (11) extending therein and having an end terminating in said housing; said passage means comprising an exhaust pressure passage; means (83) sealing said end from pressure fluid in said housing and effecting a chamber for connection to said exhaust pressure passage for relief of leakage of pressure fluid to said end of said shaft.

Claim 14

A power-steering mechanism as set forth in claim 1, said passage means comprising inlet and exhaust passages; including a check valve (67) between said inlet and exhaust passages and disposed in a bore of said housing (3), to permit reversible flow between the cylinder chambers when said piston is manually operated without pressure flow to the ends thereof.

Claim 15

A power-steering mechanism as set forth in claim 1, said control valve comprising a valve spool (132), a bore through said pressure piston (123) in which said valve spool is reciprocal; a reaction piston (136, 137) extending into a respective socket in each end of said valve spool and being carried by said valve spool; and said passage means comprising passages (130, 131) to connect said chambers to an outlet (122) pressure passage; and said passage means comprising passages to subject said sockets selectively to inlet and outlet passage pressure depending on direction of steering turn for imparting simulated steering resistance.

Claim 16

A power-steering mechanism as set forth in claim 14, including a spring (138, 139) in each of said sockets and a wall in said valve spool intermediate said sockets; each said spring acting between said wall and a reaction piston; and adjusting means (142, 143) for each spring carried by said piston (123) for prestressing the respective spring to effect a predetermined centered position of said valve spool with respect to said piston whereby said actuator and nut are likewise centered.

Claim 17

A power-steering mechanism as set forth in claim 1, a bore in said piston; a valve spool in said bore, wherein the surface of said pressure piston is relieved at each end of said bore to effect a reaction piston chamber (95, 96); a reaction piston having an end exposed in a respective chamber and carried by said piston; said relieved portions of said piston having sealing means therearound coacting with the walls of said cylinder; said passage means comprising passages to conduct pressure fluid to said housing and thence to said first mentioned grooves and communicating with said chambers; said passage means comprising control valve and housing passages whereby selected positions of said valve spool effect differential pressures at the ends therein in coaction with said reaction pistons for imparting simulated road resistance.

Claim 18

A power-steering mechanism as set forth in claim 1, wherein said nut (13) is a ball nut, and a plurality of balls intermediate said nut and said worm (2).

Claim 19

A power-steering mechanism as set forth in claim 1, said piston having a transverse bore offset from the axis thereof, said control valve comprising a reciprocal valve spool in said bore, said actuator comprising a drive finger carried by said nut and extending into said valve spool; and a spring (44) stressed intermediate said piston and said valve spool to maintain driving engagement between said finger and said valve spool.

Claim 20

A power-steering mechanism as set forth in claim 1, said nut being socketed at one end of said piston and means axially securing said nut therein while permitting rotational movement comprising a closure plate (20) at said end of said piston to retain said nut; bores (21) in said closure plate effecting passages for fluid flow to and from the respective pressure chamber and being comprised in said passage means.

Claim 21

A power-steering mechanism as set forth in claim 1, said control valve comprising a valve spool having grooves and further comprising a surrounding wall means having coacting grooves, said latter grooves communicating via passages comprised in said passage means with respective pressure chambers; said piston having a pair of longitudinal grooves communicating at all times with the ends of said valve spool for flow thereto from either longitudinal groove to the coacting grooves of said valve spool and said wall means; said passage means having passages for conducting pressure flUid from a source to said longitudinal grooves.