Fluid power steering gear

Claim 2

A fluid power steering gear comprising, in combination, a cylinder, a hydraulic circuit through which fluid is made to flow by means of a pressure source located outside of said cylinder, a piston installed in said cylinder and defining a pair of opposed chambers therewithin, said piston being operably engaged with an oscillatable member connected to a load, a rotatable member confined in said piston and operably connected to a shaft extending into said cylinder, said shaft being actuable by manually applied force, and a pair of control valve means also installed in said piston and having inner sleeve members received by stationary outer sleeve members so as to be displaced in opposite directions therein by actuating means operating through said rotatable member to actuate said control valve means when said shaft rotates for respectively and interrelatedly controlling fluid flow to and from said chambers in said hydraulic circuit.

Claim 3

A fluid power steering gear as claimed in claim 1 in which said actuating means comprises pins secured eccentrially to the end face of said rotatable member.

Claim 4

A fluid power steering gear as claimed in claim 2, in which the rotational resistance of said rotatable member is regulatable by means of a threaded member screwed into said piston.

Claim 5

A fluid power steering gear comprising, in combination, a cylinder having an inlet and an outlet for fluid fed through a hydraulic circuit by means of a pressure source located outside of said cylinder, a piston installed in said cylinder and defining a pair of opposed chambers therewithin, said piston having rack teeth on part of the body thereof which are in mesh with teeth formed on an oscillatable member connected to a load, a rotatable member confined in said piston and operably connected via a plurality of endlessly recirculating balls to a shaft extending into said cylinder, said shaft being actuable by manually applied force, and a pair of control valve means also installed in said piston and arranged in parallel with each other in a plane extending perpendicularly with respect to the axis of said shaft, said control valve means having inner sleeve members received by stationary outer sleeve members so as to bE axially displaced in opposite directions therein by means of pins secured eccentrically to the end of said rotatable member, whereby fluid flow to and from said chambers in said hydraulic circuit is interrelatedly controlled.

Claim 6

A fluid power steering gear comprising, in combination, a cylinder having an inlet and an outlet for fluid fed through a hydraulic circuit by means of a pressure source located outside of said cylinder, a piston installed in said cylinder and defining a pair of opposed chambers therewithin, said piston having rack teeth on part of the body thereof which are in mesh with teeth formed on an oscillatable member connected to a load, a rotatable member confined in said piston and operably connected via a plurality of endlessly recirculating balls to a shaft extending into said cylinder, said shaft being actuable by manually applied force, and a pair of control valve means also installed in said piston and arranged in parallel with each other in a plane extending perpendicularly with respect to the axis of said shaft, said control valve means having inner sleeve members received by stationary outer sleeve members so as to bE axially displaced in opposite directions therein by means of pins secured eccentrically to the end of said rotatable member, whereby fluid flow to and from said chambers in said hydraulic circuit is interrelatedly controlled.

Claim 7

In a fluid power steering gear, a hydraulic circuit comprising, in combination, a source of pressure fluid, a connector from said source of pressure fluid into a cylinder in which is housed said fluid power steering gear, said connector being in open communication with an axial groove formed on the periphery of a piston installed in said cylinder, said axial groove extending over a length substantially equal to the stroke of said piston, and a first and a second control valve means installed transversely in said piston and having radial ports respectively in open communication with said axial groove via passages bifurcated from said axial groove, each of said first and said second control valve means having a stationary outer sleeve member in which is slidably installed an inner sleeve member having a first and a second land, said inner sleeve members of said first and said second control valve means being normally kept in a centered position thereby to permit fluid flow throughout said hydraulic circuit, each of said first and said second control valve means further comprising first, second, third and fourth annular chambers between said outer sleeve member and said inner sleeve member, said first annular chambers of said first and said second control valve means being respectively in open communication with said radial ports, said second annular chambers being respectively normally in communication with said first annular chambers on one hand and being respectively in open communication with a pair of chambers defined by said piston within said cylinder on the other hand, one of said second annular chambers being closed from the corresponding one of said first annular chambers by the corresponding one of said first lands of said inner sleeve members upon simultaneous operation of said inner sleeve members, and said third annular chambers being respectively normally in communication with said second annular chambers on one hand and being in open communication with a reservoir located outside of said cylinder via said connector on the other hand, one of said third annular chambers being closed from the corresponding one of said second annular chambers by the corresponding one of said second lands of said inner sleeve members upon simultaneous operation of said inner sleeve members.

Claim 8

In a fluid power steering gear, a hydraulic circuit comprising, in combination, a source of pressure fluid, a connector from said source of pressure fluid into a cylinder in which is housed said fluid power steering gear, said connector being in open communication with an axial groove formed on the periphery of a piston installed in said cylinder, said axial groove extending over a length substantially equal to the stroke of said piston, and a first and a second control valve means installed transversely in said piston and having radial ports respectively in open communication with said axial groove via passages bifurcated from said axial groove, each of said first and said second control valve means having a stationary outer sleeve member in which is slidably installed an inner sleeve member having a first and a second land, said inner sleeve members of said first and said second control valve means being normally kept in a centered position thereby to permit fluid flow throughout said hydraulic circuit, each of said first and said second control valve means further comprising first, second, third and fourth annular chambers between said outer sleeve member and said inner sleeve member, said first annular chambers of said first and said second control valve means being respectively in open communication with said radial ports, said second annular chambers being respectively normally in communication with said first annular chambers on one hand and being respectively in open communication with a pair of chambers defined by said piston within said cylinder on the other hand, one of said second annular chambers being closed from the corresponding one of said first annular chambers by the corresponding one of said first lands of said inner sleeve members upon simultaneous operation of said inner sleeve members, and said third annular chambers being respectively normally in communication with said second annular chambers on one hand and being in open communication with a reservoir located outside of said cylinder via said connector on the other hand, one of said third annular chambers being closed from the corresponding one of said second annular chambers by the corresponding one of said second lands of said inner sleeve members upon simultaneous operation of said inner sleeve members.

Claim 9

A hydraulic circuit as claimed in claim 5, in which said inner sleeve members of said first and said second control valve means are normally maintained at their respective centered position by means of elastic members accommodated respectively in said fourth annular chambers of said first and second control valve means.

Claim 10

A fluid power steering gear as claimed in claim 1 in which a safety device comprising a key projecting from said rotatable member and received with allowance in a keyway cut axial on an internal surface of said piston.

Claim 11

A hydraulic circuit as claimed in claim 5 in which there are provided communication means between said reservoir and said third annular chamber, said communication means comprising, essentially, a passage 56 formed between the piston 3 and the steering shaft 8 and three passages 57, 58, and 59 formed within the steering shaft.