Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D5/00—Power-assisted or power-driven steering
  • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
  • B62D5/10—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by type of power unit
  • B62D5/12—Piston and cylinder

Definitions

• This invention relates generally to steering axle assemblies for vehicles, and more particularly to an integral power steering axle for use in a lift truck or the like.
• a double-acting cylinder in the steering system of a vehicle to turn the wheels.
• Such steering cylinders are conventionally connected to a steering axle by fasteners, such as bolts.
• Steering knuckles are pivotally connected to the steer axle by kingpins and have spindles on which the wheels are rotatably mounted.
• the kingpins are seated in bores passing through laterally spaced ends of the steering axle and include steering arms projecting therefrom.
• the conventional steering cylinder has a piston assembly with a double-ended rod interconnected between the steering cylinder and the kingpins.
• the present invention is directed to overcoming one or more of the problems as set forth above.
• a combined steering axle and cylinder assembly which comprises a bore extending through the steering axle.
• the steering cylinder assembly has a housing defined by the steering axle about the bore and a piston assembly movably positioned in the bore.
• a method for making an integral power steering axle comprises the steps of forming an elongated bore in a rigid beam and slidably mounting a piston assembly in the bore.
• a steering cylinder assembly in accordance with the present invention is thus integrally formed with the steering axle itself.
• Kingpins and the like, for interconnecting the steering cylinder and wheels of a vehicle may be assembled in very precise orientation with respect to the bore of the steering cylinder.
• misalignment between a piston assembly mounted within the bore and steering knuckles pivotally mounted on the kingpins, or the like is substantially prevented.
• the steering axle is a massive, rigid structure which resists deflection under loading and/or operation of the vehicle.
• side loading of the piston assembly is substantially prevented.
• Figure 1 is a diagrammatic side elevational view of a lift truck incorporating an integral power steering axle embodiment of the present invention
• Figure 2 is an enlarged diagrammatic, partially sectioned plan top view of the integral power steering axle embodiment
• Figure 3 is a diagrammatic partially sectioned, front elevational view of the integral power steering axle embodiment
• Figure 4 is a diagrammatic isometric and exploded view of the embodiment as in Figures 2 and 3 with parts removed for clarification purposes; and, Figure 5 is a diagrammatic view similar to
• FIG. 1 illustrates a vehicle 10, herein illustrated as a lift truck, for lifting and carrying a load.
• Vehicle 10 has a horizontally disposed frame 14 with a frame rearward portion 18.
• Vehicle 10 includes a pair of front roadwheels 20 and a pair of rear roadwheels, or first and second wheels, 22.
• Front roadwheels 20 may be mounted on a conventional drive axle (not shown) whereas rear roadwheels 22 are mounted on a steering axle 26.
• Axle 26 is connected to rear portion 18 of frame 14.
• Counterweight 19 is located adjacent rear roadwheels 22 of vehicle 10.
• steering axle 26 preferably comprises a rigid beam 28 having first and second portions shown as generally longitudinally extending, opposed lateral portions 38.
• a medial portion 40 is located between lateral portions 38 and has ends 41. Thus, lateral portions 38 project beyond ends 41.
• Steering axle 26 is connected to rear portion 18 of frame 14 by any of various conventional means.
• medial portion 40 has a forwardly projecting trunion 42 and a rearwardly projecting trunion 44.
• Each trunion 42, 44 is secured to a respective forward and rearward side 46, 48 of medial portion 40.
• Trunions 42, 44 are substantially aligned to define a longitudinal axis 50. Trunions 42, 44 are pivotally connected to the rear portion 18 of frame 14.
• steering axle 26 is permitted to oscillate about the horizontally disposed, longitudinal axis 50 of trunions 42, 44, and one rear roadwheel 22 may be raised as the other is lowered with respect to longitudinal axis 50.
• each lateral portion 38 of axle 26 is Identical to the other and together define a bilaterally symmetrical relationship.
• the lateral portion 38 is formed as a bifurcated structure 52 having spaced apart upper and lower arms 54, 56. Kingpins 60 are seated for pivotal movement in a pair of bearings 62. Each bearing 62 is fitted in a respective aperture or bore 64, 66. Aperture 64 is formed in the upper arm 54, whereas aperture 66 is formed in the lower arm 56. Apertures 64, 66 are aligned and together define an axis 68. Referring to Figure 2, a steering knuckle
• Steering knuckle 70 is connected to the kingpins 60 and has a spindle 72 upon which rear roadwheel 22 is mounted.
• Steering knuckle 70 also has an outwardly projecting steering arm 74 which is pivotally fastened by pivot pin 76 to one end 80 of a tie link 82.
• a double-acting, fluid steering cylinder assembly 83 functions to power pivotal movement of roadwheels 22 into and out of a plane passing through roadwheels 22 and perpendicular to spindle 72.
• a novel aspect of this invention resides in the structural integration of cylinder assembly 83 with steering axle 26.
• the integration of the cylinder assembly 83 and axle 26 shall be hereinafter referred to as an integral power steering axle 84 in accordance with the present invention.
• medial portion 40 of axle 26 has a longitudinally extending, cylindrical bore 86.
• Bore 86 extends along an axis 89 and opens onto medial portion ends 41.
• Axis 89 lies in a plane passing midway through axis 68 between apertures
• bore 86 is an integral part of steering cylinder 83 as steering axle 26 defines a housing 87 of steering cylinder assembly 83 at medial portion 40 about bore 86.
• the bore 86 has a longitudinally extending, cylindrical surface 88.
• a cylindrical sleeve, not herein illustrated, could be snugly inserted coaxially within bore 86.
• surface 88 shall include either the surface itself or the surface of a sleeve.
• a piston rod assembly 90 of steering cylinder 83 is reciprocally mounted within bore 86 and includes a piston 92 and a double-ended piston rod 94. Piston 92 longitudinally reciprocates and slidably engages cylinder wall 88 of bore 86.
• Steering cylinder 83 is connected to a source of pressurized hydraulic fluid in a conventional fashion such that application of hydraulic fluid to the steering cylinder 83 will cause the piston assembly 90 to move in one direction or the other depending upon the direction of flow of the pressurized fluid.
• FIG 4 illustrates that housing 87 is structurally an integral portion of steering axle 26, and that bore 86 is precisely machined for proper orientation with respect to apertures 64, 66.
• housing 87 is structurally an integral portion of steering axle 26, and that bore 86 is precisely machined for proper orientation with respect to apertures 64, 66.
• a connection between steering knuckles 70 and double-ended piston rod 94 may be by various conventional means.
• tie link 82 is pivotally fastened by a pivot pin 108 to piston rod 94.
• Such formation is preferably by casting beam 28 with bore 86 being cored through the medial portion 40 of the casting, and trunions 42, 44 extending from medial portion 40 of the casting.
• Bore 86 is normally cast slightly under the desired, final diameter size, and may then be machined to within close tolerances so as to provide a smooth, cylindrical wall suitable as cylinder surfaces 88.
• Apertures 64, 66 are then machined in both lateral portions 38. This machining is fixtured, or oriented, with respect to bore 86.
• Piston assembly 90 is then slidably mounted in bore 86.
• bore 86 could be formed oversize and have a tubular cylindrical sleeve secured therein.
• a pair of end caps 113 each having a bore 114 are inserted in opposite ends 116 of bore 86.
• a plurality of seals 120 are disposed in annular grooves in each end cap 113 for sealing engagement with piston rod 94.
• Seals 122 are disposed in annular grooves in each end cap 113 for sealing engagement with surface 88. Since power steering axle 84 is a rigid, integral structure, substantially no deflection of piston rod 94 with respect to end caps 113 will occur, and thus steering cylinder 83 is protected against binding during operation thereof.
• integral power steering axle embodiment 84' Integral power steering axle 84' is similar in construction to the previously described embodiment 84 and is substantially equivalent in function.
• Integral power steering axle 84' primarily differs from embodiment 84 in the manner of manufacture. Rather than the casting described for embodiment 84, integral power steering axle 84' forms a rigid beam 28' by fusing, e.g., welding, a plurality of plates 132, 134 and 136 and a cylinder housing 87' together. More particularly, housing 87' may be a cylindrically shaped tube having an elongated bore 86' therethrough. At each end 116' of bore 86' is welded an end plate 136. A pair of generally longitudinally extending top and bottom plates 132 are then welded to end plates 136. Top and bottom plates 132 extend beyond the junction of plates 136.
• top and bottom plates 132 beyond a medial portion 40' and end plates 136 are analogous to terminal portions 38 and hence are denoted as terminal portions 38'.
• Housing 87' is thus rigidly held between top and bottom plates 132, and has bore 86' extending in a direction generally parallel to lateral portions 38' of top and bottom plates 132.
• a pair of front and rear plates 134, each having a respective trunion 42', 44' affixed thereto, are welded to top and bottom plates 132 in a preferably generally perpendicular orientation with respect to end plates 136.
• Bores 64', 66' may then be machined in lateral portions 38'. The machining is oriented transversely with respect to and fixtured from bore 86'.
• a piston assembly 90' is then slidably mounted in bore 86'.
• integral power steering axle embodiments 84, 84' find particular application as the steering axles of lift trucks, with fluid cylinders 83, 83' functioning to power the steering of roadwheels 22.
• integral power steering axle embodiments 84, 84' will find other applications, particularly applications in vehicles other than lift trucks.
• kingpins 60 and the like, for interconnecting steering cylinder 83,83' and roadwheels 22 of a vehicle may be assembled in very precise orientation with respect to the bores 86, 86' of steering cylinders 83, 83'.
• misalignments between piston assemblies 90, 90' and steering knuckles 70 are substantially prevented and piston rods 94, 94' are protected from side loading by the stiff cylinder housing 87, 87'.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)

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• 1980
  • 1980-09-18 WO PCT/US1980/001230 patent/WO1982000983A1/en not_active Application Discontinuation
  • 1980-09-18 EP EP19810901181 patent/EP0060248A1/en not_active Withdrawn
• 1981
  • 1981-09-14 JP JP1981135613U patent/JPS5769765U/ja active Pending

Non-Patent Citations (1)

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