Steering axle
In rail vehicles without a bogie , steering axles are axles that are not rigidly mounted in the frame, but rather have a certain amount of play (mobility) and can adjust radially in a curve. This improves the curvature of the carriages and reduces wear on the wheel flanges and rail heads.
Steering axes can be controlled, for example derived from the lateral displacement of the central axis in the tram steering three- axle vehicles .
In trucks and buses , steering axles refer to active, electronically or hydraulically steered additional axles, i.e. not the front axle, which is rigidly connected to the steering wheel. see steer-by-wire ➔ self-steering axle
In floor conveyor technology , the term steering axle is used, for example, for the rear, steered axle on forklifts .
Steering axles on the railroad
Free steering axles are often used on the railroad . Due to the conical running surfaces in the curve, you can automatically adjust radially by increasing the play between the axle bearing and the axle holder. The inclined spring hooks, in conjunction with the sinusoidal movement, cause the reset in the straight track. Their development became necessary because the constantly increasing loads required ever longer railroad cars and thus larger wheelbases. The regulations for the use of steering axles, which allow a lower pulling resistance in curves than rigid axles, were regulated in national standards. The smallest minimum curve radius that vehicles with rigid axles could drive on was 300 m in Germany , and the largest axle base permitted for rigid axles was 4 m. For vehicles with a larger wheel base and rigid axles, such as the DR series VT 2.09 , an exemption was required.
Club steering axles
Club steering axles get their name from the revision of the steering axle designs by the VDEV and contain the decree of 1882 that only steering axle designs approved by the VDEV are permitted for railway vehicles. The term club steering axles excluded bogies with more than one axle and individual axles that did not allow a larger deflection from the center position of 5 mm when adjusted to the curvature. In the case of two-axle freight wagons, the free steering axle has prevailed over time, allowing less maintenance and easier operation. In the case of a club steering axle, the play of the axle bearing housing in the axle holder is increased in the longitudinal direction. The suspension spring is suspended from inclined spring hooks. Due to the equivalent conicity of the wheel running surfaces, the wheelset can adjust radially in a curve, the weight of the vehicle generates a restoring force via the inclined spring hooks in addition to the self-centering of the wheelset in the track, which returns the wheelset to the straight track. Only with three-axle wagons were attempts made with a coupled steering axle construction. The middle axle of such a car was laterally displaceable and connected to the end axles via a lever linkage. If the car entered an arc, the middle axle was shifted sideways so that the end wheelsets were adjusted radially via the handlebars. While the principle found a certain widespread use in tramcars as steering three-axle vehicles , the effort proved to be unnecessary in the long run under long-distance railway conditions. Three-axle wagons were usually equipped with free steering axles like two-axle vehicles, the central axis was given lateral play by the suspension of the suspension springs in oblique hooks and corresponding distances between the axle box and axle holder. This meant that there was no need for handlebars and joints that are susceptible to wear.
Steering axles in vehicles with their own energy source
When the first self-propelled railcars were put into service, steering axles were also required with a wheelbase of around 6.5 m and a curve radius of 180 m. Practice has shown that on the front axles of these vehicles, the free steering axles did not adjust to the radius of curvature, but cut it. That is why almost all two-axle railcars with a larger wheelbase have steering axles with a drawbar frame according to the enclosed sketch. Here the axles are positively guided in a curve by the drawbar frame. As with free steering axles, the spring hangers, on which the load of the car body rests, are returned to the initial position.
In steam locomotives there are special constructions for the deflection of the running axles, see Adams axle , Bissel frame and Krauss-Helmholtz frame .
photos
Freight car steering axle with angled double spring hook
Steering three-axle bogie of a tram railcar
Bissel frame of a narrow-gauge steam locomotive
Web links
Individual evidence
- ↑ a b Internet site about steering axles on Zeno.org
- ↑ View of a free steering axle construction from a freight car from zeno.org
- ↑ View of a coupled steering axle construction on a three-axle vehicle
- ↑ Steinhoff: A new light metal diesel railcar with the mechanical power transmission of the HBE. In: Verkehrstechnik. 1928, p. 701.
