Truck steering gear, also known as steering gear or steering gear, is the most important component in the truck steering system. Its function is to increase the force transmitted by the steering wheel to the steering transmission mechanism and change the direction of force transmission.
Commonly used include gear and rack type, worm crank pin type, and circulating ball type.
1) Rack and pinion steering gear: It is the most common type of steering gear. Its basic structure is a pair of small gears and racks that mesh with each other. When the steering shaft drives the pinion to rotate, the rack moves in a straight line. Sometimes, relying on the rack to directly drive the tie rod can cause the steering wheel to turn. So, this is the simplest steering gear. Its advantages are simple structure, low cost, sensitive steering, small size, and the ability to directly drive the tie rod. Widely used on trucks.
2) Worm crank pin steering gear: It is a steering gear with the worm as the driving component and the crank pin as the driven component. The worm has trapezoidal threads, and a finger shaped tapered finger pin is supported on the crank by bearings. The crank is integrated with the steering rocker shaft. When turning, the worm is rotated through the steering wheel, and the conical finger pin embedded in the spiral groove of the worm rotates on one side and moves in an arc around the steering rocker arm shaft, thereby driving the crank and steering arm to swing, and then the steering wheel is deflected through the steering transmission mechanism. This type of steering gear is usually used on trucks with high steering force.
3) Circulating ball steering gear: The main structure of the circulating ball assisted steering system consists of two parts: mechanical part and hydraulic part. The mechanical part consists of a 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 a screw and nut, and the other pair is a rack, toothed segment, or toothed shaft. A steel ball that can roll circularly is installed between the screw rod and the rack nut, so that sliding friction becomes rolling friction, thereby improving the transmission efficiency. The advantages of this type of steering gear are light handling, low 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.