The common types of automobile steering gear are gear rack type, worm crank pin type and circular ball type.

1) rack and pinion steering gear: it is one of the most common steering gear. The basic structure is a pair of small gear and a rack which are engaged with each other. When the steering shaft drives the pinion to rotate, the rack will make the linear motion. Sometimes, the transverse rod can be directly driven by the rack, and the steering wheel can be turned. So, this is one of the most simple steering gear. It has the advantages of simple structure, low cost, sensitive steering, small size, and can directly drive the transverse rod. Widely used in the car.

2) the worm crank pin type steering gear: it is based on the worm as the driving part, the crank pin is the steering gear of the follower. The worm is provided with a trapezoidal thread, and the finger like tapered finger pin is supported on the crank, and the crank and the steering rocker shaft are integrated into a whole. When steering, the steering wheel through the tapered rotatingworm helical worm embedded in the groove of the finger side of the rotation around the side of the steering arm shaft of arc movement, thereby driving and steering crank arm swing down, then the steering wheel through the steering transmission mechanism causes deflection. This kind of steering gear is usually used in a truck with a larger steering force.

3) recirculating ball type steering gear: the main structure of the recirculating ball steering system is composed of two parts: mechanical part and hydraulic part. The mechanical part is composed of a casing, a side cover, an upper cover, a lower cover, a circular ball screw, a rack and nut, a rotary valve valve core and a fan gear shaft. There are two pairs of transmission pairs: one pair is a screw, a nut, and the other is a rack, a gear fan or a fan gear shaft. A rolling ball is arranged between the screw rod and the rack nut, and the sliding friction is changed into rolling friction, thereby increasing the transmission efficiency. The advantage of this kind of steering gear is that it is easy to operate and has little wear and long life. The disadvantage is that the structure is complex, the cost is higher, and the steering sensitivity is not as high as that of the gear rack.