A kingpin is a pivot rod of a swivel joint of parts of transport machines [1] . In a narrower sense, the axis of rotation of the steered wheel of a car or other vehicle.
In times of horse-drawn carriages, they called a “pivot” or “pivot” called a rod or bolt, “on which the front of any wagon goes” [2] , that is, the one through which the turning axle of the front wheels was attached to the wagon [3] .
In diesel locomotives, electric locomotives and wagons, a pivot with a vertical axis is used to connect the wheel carts to each other and to the frame of the machine. [one]
In the car, in its original version, it was a very real hardened steel axle rotating in roller or needle bearings or bronze bushes, with the help of which the steering knuckle bearing the hub and wheel was pivotally mounted to the suspension .
Beginning in the 1950s, in cars, the king pin as an independent element of the front wheel suspension was gradually replaced by ball joints that connected the steering knuckle to the suspension arms and ensured, thanks to the presence of two degrees of freedom, both its compression and rebound moves and the rotation steered wheels.
Ball joints are sealed or semi-hermetic, therefore either do not require lubrication at all, or they are much less likely to be compared to leaky conventional swivel joints. In addition, in the pivot suspension it was very difficult or even impossible to implement some new solutions in the field of suspension kinematics, for example, a reduced rolling arm or “anti-pecking” lever geometry. By the mid-1960s, the pivots remained mainly in the suspension of trucks, pickups and SUVs, as well as rare passenger cars oriented to work under heavy loads or in difficult road conditions - for example, on some sports cars and “hard” SUVs, Australian Holden cars , the Soviet brand " Volga " or the German "Beetle" , where they were used because of the greater survivability. In addition, the dependent front suspension with an integral beam of the bridge almost always has pivots for structural reasons (but not always in the form of a real axis - for example, on UAZ all-wheel drive vehicles, pivots are spherical hinges mounted on top and bottom on the steering knuckle with brass bushings).
Nevertheless, the word "kingpin" continues to be widely used, designating now not the real, but the constructive axis of rotation of the wheel. For example, in the case of a suspension on double wishbones, this is the axis connecting the centers of both of its ball joints.
In the MacPherson- type suspension, which is characteristic of many modern cars, the shock absorber strut essentially plays the role of a king pin, the mobility of which is ensured by a ball joint from below and a thrust bearing from above.
For driving performance of a car, a very important role is played by such a parameter as the angles of inclination of the kingpin - longitudinal ( castor ) and transverse.
Notes
- ↑ 1 2 Great Soviet Encyclopedia.
- ↑ Dahl's Dictionary.
- ↑ Shvornev // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.