Classification of automobile steering gear:
1) Rack and pinion steering gear: it is the most common steering gear. Its basic structure is a pair of meshing pinion and rack. When the steering shaft drives the pinion to rotate, the rack will move in a straight line. Sometimes, the steering wheel can be steered by directly driving the tie rod by the rack. Therefore, this is the simplest steering gear. The utility model has the advantages of simple structure, low cost, sensitive steering and small volume, and can directly drive the tie rod. It is widely used in automobiles.
2) Worm crank pin steering gear: it is a steering gear with worm as driving part and crank pin as driven part. The worm has trapezoidal thread, the finger shaped conical finger pin is supported on the crank with bearing, and the crank is integrated with the steering rocker shaft. During steering, rotate the worm through the steering wheel, and the conical finger pin embedded in the worm spiral groove rotates while making circular motion around the steering rocker shaft, so as to drive the crank and steering pitman arm to swing, and then deflect the steering wheel through the steering transmission mechanism. This kind of steering gear is usually used on trucks with large steering force.
3) Recirculating ball steering gear: recirculating ball power steering system [2] is mainly composed of two parts: mechanical part and hydraulic part. The mechanical part is composed of shell, side cover, upper cover, lower cover, circulating ball screw, rack nut, rotary valve core and fan gear shaft. There are two pairs of transmission pairs: one pair is screw and nut, and the other pair is rack, tooth fan or fan tooth shaft. A circulating rolling steel ball is installed between the screw and the rack nut to change the sliding friction into rolling friction, so as to improve the transmission efficiency. The steering gear has the advantages of light operation, small wear and long service life. The disadvantage is that the structure is complex, the cost is high, and the steering sensitivity is not as good as the rack and pinion type.
