Patent ID: 7258034
Filing Date: 2007-08-21
Classification: B62D,Y10T

Abstract:
1. An apparatus for protecting impact to a rack bar of a power steering gearbox, the apparatus comprising: an oil pressure cylinder, to which oil has passed through an oil pressure pump and a rotary valve is supplied through a left port or right port; a rack bar in the oil pressure cylinder and horizontally reciprocating therein; a piston secured to the rack bar; a first rack bush and a second rack bush positioned at both ends of the cylinder, in which the piston moves, to close the cylinder; and bypass holes comprising depressions formed in the walls of the cylinder with an outward convex shape, each bypass hole being substantially greater in size than an entire axial width of the piston such that fluid flows around the piston when the piston is positioned at one of the bypass holes, the bypass holes being disposed at both ends of the cylinder adjacent to the first and second rack bushes and all the bypass holes being separate and distinct from the left and the right ports, wherein the piston has a uniform outer periphery throughout its axial length, each bypass hole is substantially greater in length than the entire axial length of the piston, and wherein the cylinder protrudes outwardly thereof at a position corresponding to the bypass hole.