Power steering system

Claim 2

A power steering system comprising an input shaft, an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft, a valve housing coupled in unitary construction to said output shaft, said input shaft being fitted into said valve housing with a gap therebetween, and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which in turn is interposed between said valve spool and said lever rods, said inpUt shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotably fixed between said valve spool and said lever rods, both ends of said pair of head levers being firmly pressed against free ends of said valve spool and said lever rods respectively, whereby in response to the relative angular displacement between said input shaft and said valve housing, said valve spool may be shifted through said arm, said lever rods and said head levers.

Claim 3

A power steering system as specified in claim 1 wherein said input shaft has projections which are adapted to fit into groove means formed in said valve housing, whereby the relative angular displacement between said input shaft and said valve housing is limited by said projections and said groove means.

Claim 4

A power steering system comprising an input shaft, an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft, a valve housing coupled in unitary construction to said output shaft, said input shaft being fitted into said valve housing with a gap therebetween, and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which latter is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotably fixed between said valve spool and said lever rods, opposite ends of said pair of head levers being firmly pressed against free ends of said valve spool and said lever rods respectively, said valve housing having a pair of plungers which are slidably fitted into the respective lever rods respectively, each of said plungers being provided with an end face which is exposed in a working liquid, engaging means which stops said plunger at a predetermined position when said plunger is pushed into said lever rod, and means which is adapted to engage with said lever rod when said plunger is moved away therefrom for effecting the movement in unison with said lever rod, whereby said valve spool is shifted via said arm, said lever rods and said head levers in response to said relative angular displacement between said input shaft and said valve housing and either of said plungers is moved away from said lever rod in response to the movement thereof, thereby generating the hydraulic reaction force.

Claim 5

A power steering system comprising an input shaft, an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft, a valve housing coupled in unitary construction to said output shaft, said input shaft being fitted into said valve housing with a gap therebetween, and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which latter is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotably fixed between said valve spool and said lever rods, opposite ends of said pair of head levers being firmly pressed against free ends of said valve spool and said lever rods respectively, said valve housing having a pair of plungers which are slidably fitted into the respective lever rods respectively, each of said plungers being provided with an end face which is exposed in a working liquid, engaging means which stops said plunger at a predetermined position when said plunger is pushed into said lever rod, and means which is adapted to engage with said lever rod when said plunger is moved away therefrom for effecting the movement in unison with said lever rod, whereby said valve spool is shifted via said arm, said lever rods and said head levers in response to said relative angular displacement between said input shaft and said valve housing and either of said plungers is moved away from said lever rod in response to the movement thereof, thereby generating the hydraulic reaction force.

Claim 6

A power steering system, comprising an input shaft; an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft; a valve housing coupled in unitary construction to said output shaft, said output shaft being fitted into said valve housing with a gap therebetween; and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which latter is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotally fixed between said valve spool and said lever rods with opposite ends of said pair of head levers being firmly pressed against free ends of said valve spool and lever rods respectively, said valve housing having a pair of plungers which are slidably fitted into said lever rods respectively, each of said plungers being provided with an end face which is expoSed to a working liquid, engaging means which stops the respective plunger at a predetermined position when the plunger is pushed into the associated lever rod, and means adapted to engage with the respective lever rod when the associated plunger is moved away therefrom for effecting movement of the plunger in unison with said associated lever rod, whereby said valve spool is shifted via said arm, said lever rods and said pair of head levers in response to relative angular displacement between said input shaft and said valve housing, either of said plungers being moved away from said lever rod in response to the movement thereof, thereby generating a hydraulic reaction force, and whereby when the hydraulic pressure acting upon said end face of the respective plunger is in excess of a predetermined value, the other plunger is pushed into the associated lever rod against a coiled spring, thereby cutting off said hydraulic reaction force.

Claim 7

A power steering system, comprising an input shaft; an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft; a valve housing coupled in unitary construction to said output shaft, said output shaft being fitted into said valve housing with a gap therebetween; and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which latter is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotally fixed between said valve spool and said lever rods with opposite ends of said pair of head levers being firmly pressed against free ends of said valve spool and lever rods respectively, said valve housing having a pair of plungers which are slidably fitted into said lever rods respectively, each of said plungers being provided with an end face which is expoSed to a working liquid, engaging means which stops the respective plunger at a predetermined position when the plunger is pushed into the associated lever rod, and means adapted to engage with the respective lever rod when the associated plunger is moved away therefrom for effecting movement of the plunger in unison with said associated lever rod, whereby said valve spool is shifted via said arm, said lever rods and said pair of head levers in response to relative angular displacement between said input shaft and said valve housing, either of said plungers being moved away from said lever rod in response to the movement thereof, thereby generating a hydraulic reaction force, and whereby when the hydraulic pressure acting upon said end face of the respective plunger is in excess of a predetermined value, the other plunger is pushed into the associated lever rod against a coiled spring, thereby cutting off said hydraulic reaction force.

Claim 8

A power steering system comprising an input shaft, an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft, a valve housing coupled in unitary construction to said output shaft, said input shaft being fitted into said valve housing with a gap therebetween, and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which in turn is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotably fixed between said valve spool and said lever rods, opposite ends of said pair of head levers being fairly pressed against free ends of said valve spool and said lever rods respectively, a hydraulic pressure chamber defined between opposite ends of each of said lever rods, whereby said valve spool is shifted through said arm, said lever rods and said pair of head levers in response to said relative angular displacement between said input shaft and said valve housing and a load pressure is applied to either of said hydraulic pressure chambers, thereby correcting the steering torque.

Claim 9

A power steering system comprising an input shaft, an output shaft coupled in coaxial alignment with said input shaft through a torsion bar for angular displacement with respect to said input shaft, a valve housing coupled in unitary construction to said output shaft, said input shaft being fitted into said valve housing with a gap therebetween, and a valve spool and lever rods which are slidably fitted into said valve housing in parallel with each other but at right angles relative to said input shaft which in turn is interposed between said valve spool and said lever rods, said input shaft having an arm extending at a right angle relative thereto and being in engagement with both of said lever rods so as to displace them in the axial direction thereof, said valve housing having a pair of head levers which are pivotably fixed between said valve spool and said lever rods, opposite ends of said pair of head levers being fairly pressed against free ends of said valve spool and said lever rods respectively, a hydraulic pressure chamber defined between opposite ends of each of said lever rods, whereby said valve spool is shifted through said arm, said lever rods and said pair of head levers in response to said relative angular displacement between said input shaft and said valve housing and a load pressure is applied to either of said hydraulic pressure chambers, thereby correcting the steering torque.

Claim 10

A power steering device, comprising input shaft means; output shaft means coaxially aligned with said input shaft means; torsion bar means coupling said output shaft means with said input shaft means for angular displacement relative to the latter; a valve housing coupled for movement with said input shaft means and surrounding the same with clearance; a slidable valve member and a pair of slidable rods accommodated in said valve housing at opposite sides of said input shaft means and extending transversely of the latter; an engaging portion rigid with said input shaft means extending transversely thereof and engaging said rods operative for effecting alternate axial displacement thereof; and a pair of levers rockably mounted in said valve housing for displacement transversely to the elongation of said input shaft means and each having opposite end portions in engagement with a free end of said valve member and of one of said rods, respectively.

Claim 11

A power steering device, comprising input shaft means; output shaft means coaxially aligned with said input shaft means; torsion bar means coupling said output shaft means with said input shaft means for angular displacement relative to the latter; a valve housing coupled for movement with said input shaft means and surrounding the same with clearance; a slidable valve member and a pair of slidable rods accommodated in said valve housing at opposite sides of said input shaft means and extending transversely of the latter; an engaging portion rigid with said input shaft means extending transversely thereof and engaging said rods operative for effecting alternate axial displacement thereof; and a pair of levers rockably mounted in said valve housing for displacement transversely to the elongation of said input shaft means and each having opposite end portions in engagement with a free end of said valve member and of one of said rods, respectively.