What is the effect of steering joint on automobile steering system?

Steering knuckle, also known as "sheep's horn", is one of the important parts in the automobile steering bridge, which can make the automobile run stably and transfer the driving direction sensitively.
The function of the steering knuckle is to transfer and bear the front load of the car, support and drive the front wheel around the kingpin to turn the car. In the vehicle running state, it bears variable impact load, so it is required to have high strength.

Steering Knuckle Construction

The knuckle is the hinge on which the wheel turns, usually in a forked shape. The upper and lower forks have two coaxial holes for mounting the kingpin, and the steering knuckle journal is used for mounting the wheel. The two ears of the pin hole on the steering knuckle are connected to the fist-shaped part at both ends of the front axle by the king pin, so that the front wheel can be deflected around the king pin at a certain Angle to turn the car. To minimize wear, bronze bushings are pressed into the knuckle pin holes, and the bushings are lubricated with grease injected into a grease nozzle mounted on the knuckle. In order to make the steering flexible, a bearing is arranged between the lower lug of the steering knuckle and the fist part of the front axle. Adjusting gaskets are also provided between the knuckle upper ear and the fist part to adjust the gap between them.

Steering Wheel Positioning Parameters

In order to maintain the stability of straight driving, steering portability and reduce the wear between tires and parts, the steering wheel, steering knuckle and front axle must maintain a certain relative position between the frame, this installation with a certain relative position is called steering wheel positioning, also known as front wheel positioning. Correct front wheel positioning should be done: can make the car straight line running stability without swing; When steering, the force on the steering wheel is small; The steering wheel after steering has the function of automatic righting; No skid between tire and ground to reduce fuel consumption and prolong tire service life. Front wheel positioning includes kingpin backward tilt, kingpin inward tilt, front wheel outward tilt and front wheel bundle.

The Working Principle Of

1. Inner Angle Of Kingpin

The function of the kingpin Angle is to set the wheel automatically. Usually the wheel axis is not horizontal, for the sake of illustration, it is assumed that the wheel axis is horizontal when driving in a straight line. And when the car runs in a straight line, the Angle of intersection between the wheel axis and the kingpin is just this maximum.

The Angle between the wheel axis and the kingpin is constant in the steering process, when the wheel turns an Angle, the wheel axis will leave the horizontal plane to tilt down, causing the body to lift, potential energy increase. The car's own gravity has the effect of returning the steering wheels to their original middle position. When the car is parked horizontally, in the transverse vertical plane of the car, the Angle between the main pin axis and the ground vertical line is the inner Angle of the main pin.

2. Camber Angle Of Front Wheel

If the installation of the wheel when empty is just perpendicular to the road surface, the axle may tilt inward because of bearing deformation when full, which will accelerate the wear of the car tire. In addition, the axial component of the vertical reaction force of the road surface to the wheel along the hub will make the hub press the small bearing towards the outer end, increase the load of the small bearing and the hub fastening nut at the outer end, and reduce their life. But camber Angle should not be too large, otherwise it will make the tire wear. As shown in the figure on the left, when the car is parked horizontally, in the horizontal vertical plane of the car, the Angle between the wheel plane and the ground perpendicular is the front wheel camber.

3. Front Wheel Bundle

With camber, the wheels roll like cones, causing both wheels to roll outward. As a result of the steering rod and the constraints of the axle wheel will not roll away, the wheel will appear on the ground to slide inward, thereby increasing the tire wear. In order to avoid the adverse consequences caused by conical rolling effect, the two front wheels are appropriately deflected inward to form the front wheel bundle.

Characteristics Of

The shape of the steering knuckle is complex, concentrating the structural characteristics of the shaft, sleeve, disk ring and fork frame, which are mainly composed of three parts: supporting journal, flange and fork frame. The structure shape of the supporting journal is a step shaft, which is characterized by a rotating body composed of coaxial cylindrical surface, conical surface, threaded surface, and axial shoulder, transition fillet and end face perpendicular to the axis line. Flange comprises a flange face, a uniform connecting bolt through hole and a thread hole steering limit; The fork frame is composed of the upper and lower ears of the steering knuckle and the flange surface of the fork frame.