Abstract: Described is a steering rack bar which is low in costs, which is hollowed in overall length, and for use in steering equipment for automobiles. A rack is formed on a first steel tube by plastic working, wherein the first steel tube has good plastic workability by low carbon content, and has high strength after hardening. The above first steel tube and a second steel tube are joined to complete a hollow steering rack bar, wherein the second steel tube has a higher carbon content and is lower in cost than the first steel tube. Moreover, the second steel tube which has a margin of the strength can be thinner than the first steel tube for reduction of weight.

Abstract: This invention aims to provide a steering rack bar in low costs, which is hollowed in overall length, and for use in steering equipment for automobiles. A rack is formed on a first steel tube by plastic working, wherein the first steel tube has good plastic workability by low carbon content, and has high strength after hardening. The above first steel tube and a second steel tube are joined to complete a hollow steering rack bar, wherein the second steel tube has a higher carbon content and is lower cost than the first steel tube. Moreover, the second steel tube which has a margin of the strength can be thinner than the first steel tube for reduction of weight.

Abstract: A method for manufacturing a hollow rack bar having a flat portion thick enough, which prevents difficulty in pulling out a core after press working. The flat portion is formed by inserting the core having an approximately central depression in the longitudinal direction into a steel pipe and pressing the steel pipe from the outside by an upper and a lower dies. Subsequent to the formation of the flat portion, rack teeth are formed by placing the steel pipe in a tooth profile forming die and forcibly inserting a mandrel into the steel pipe.

Abstract: In the power steering apparatus, a casing comprises integrated separate sections of a valve casing in which a control valve is incorporated, a cylinder tube of a power cylinder, and a gear casing in which a steering gear is incorporated. In the cylinder tube are formed a pair of supply/discharge passages, which are parallel to the axial direction of the cylinder tube, and through which hydraulic fluid flows into/from the power cylinder. In the gear casing are formed, by casting, a pair of pipes which communicate with a pair of supply/discharge passages. In the valve casing are formed a pair of supply/discharge ports which communicate with the pair of pipes.

Abstract: A rack and pinion steering device which reduces the generation of unusual sounds or vibrations. An auxiliary shaft (36) is slidably supported by a pair of bearings (32) and (34). The pair of bearings are arranged parallel to a rack shaft (10) at a predetermined interval on a device unit (1) which supports the rack shaft (10) in such a manner that the rack shaft (10) can reciprocate. A spherical portion (60) is formed on the end of the rack shaft (10) and swingably engaged in a connecting member (58) to interconnect the end of the rack shaft (10) and the connecting member (58). The end of the auxiliary shaft (36) is also fixed to the connecting member (58), and opposite tie rods (38) and (40) are connected to the auxiliary shaft (36) between a pair of bearings (32) and (34) via ball joints (42) and (44).

Abstract: A power steering device comprising an input shaft connected to a steering shaft, an output shaft connected to a rack for driving vehicle wheels, a servo valve including a valve sleeve surrounding the input shaft and engaging the output shaft, and a torsion bar with both ends secured to the input shaft and the output shaft. In the power steering device, the torsion bar is positioned and secured via a balance pin in the input shaft. The balance pin has multiple projecting portions arranged alternately on opposite sides of the balance pin along the length of the balance pin. After inserting the balance pin into the input shaft and the torsion bar, the input shaft and the torsion bar are relatively rotated by the protruding portions of the balance pin. The servo valve is thus correctly centered. The hydraulic pressure produced by the servo valve is balanced.

Abstract: A control valve is disclosed herein. The control valve includes a valve sleeve and a rotor which is rotatably inserted into the valve sleeve. The valve sleeve have a plurality of fluid passages comprising a plurality of through passages which pass through the wall of the valve sleeve and a plurality of recessed grooves axially elongated on the inside surface of the valve sleeve. The rotor has a plurality of fluid passages opposing with said fluid passages of the valve sleeve. The fluid passages of the rotor cooperate with said fluid passages of the valve sleeve to open and close fluid flow. The valve sleeve has fluid flow noise suppress means formed by many continuous undulations along side edges of the recessed groove of the valve sleeve.