Process for Fabricating Hollow Races or Wheels Provided at Their Lateral Ends With Axle Stumps in Which Process Substantially No Chips Are Produced; And Races and Wheels Manufactured in Accordance With This Process

The present invention relates to a process for fabricating cylindrical, hollow races, rollers or wheels having axle stumps at their lateral ends. This novel fabricating process is capable of producing the end product without the accompanying chips that fall off in the conventional machining process. The invention relates to a special race made in accordance with this process.

The aforedescribed types of races or rollers were heretofore made out of piping cut to the desired supporting length. After the cutting step plates were welded to both lateral sides of the roller and to those plates the axle stumps are then affixed. The axle stumps serve as the inner seat of a roller bearing and also as the seat for a drive pinion. It was necessary in the manufacture of the aforedescribed prior art devices to utilize mechanical tools which produce chips, in order to achieve a corresponding manufacturing precision with a minimal knocking and with a corresponding snug fit. Furthermore, it was generally necessary to subject the entire roller subsequent to the manufacturing process to a straightening process. The disadvantages of this prior art manufacturing process reside in that a plurality of parts must be separately manufactured and joined and worked upon.

It is an object of this invention to provide a manufacturing process wherein the aforedescribed disadvantages are avoided and in which the aforedescribed races and rollers are fabricated without the production of chips. With the process of the invention therefore there can be produced a finished roller in a simple and economical manner having a high running precision. It is a further object of this invention to provide a process by means of which the running rollers can be produced without accompanying chips.

The objects of the invention as well as the process for making the races, rollers and wheels and the running rollers, wheels and races themselves will now be explained in detail in conjunction with the accompanying drawings, wherein there is illustrated:

FIG. 1 illustrates a running roller in accordance with the invention; and

FIG. 2 illustrates the end of a roller of the invention which has been reshaped in accordance with the process of the invention before the turning-in, bending and crimping step has been carried out.

As can be clearly recognized from FIG. 1 of the drawing, the running roller consists of a pipe portion 2, made out of a conventional pipe material, the exterior diameter of which corresponds to that of the running roller. At the end of the running roller pipe 2 there is provided a turned-in or bent-in portion 4 which adjoins a bulging portion 6 adapted to act as a ball race. The axle stump 10 is affixed to the bulging portion 6 by means of a fillet weld 8. The axle stump 10 includes a conical portion 12, a hexagonal portion 14, a further conical portion 16 and a cylindrical end piece 18 for receiving a roller bearing. There will now be explained in detail the shaping of the turned-in portion 4 and the axle stump 10 which is provided at both ends of the running roller tube 2, particularly in conjunction with FIG. 2 of the drawing. Turning-in of the portion 4 and the shaping of the axle stump 10 is carried out with the aid of a pipe shaping or deforming machine. The pipe shaping machine can, for example, be a pressing machine as described in the publication "Maschinenmarkt", 70th year edition (1964) No. 73 on page 88.

The shaping is carried out in eight drawing or rolling steps. A corresponding shaping tool is provided in the revolving head of the pipe deforming machine for each drawing, pressing or rolling step, the head being pressed on the pipe end. First of all the pipe ends are reduced to about half the running roller diameter by means of two drawing steps. By means of this shaping process there result the two frusto-conical sections 20, 22 with increased wall thickness at the pipe ends. Thereafter, the running roller pipe 2 is returned to the clamping portion of the pipe shaping machine, so that the transfer region from the running roller pipe 2 to the conical portion 20 is positioned within the clamping jaw and thereafter during a third drawing or rolling step the bulging portion 6 is shaped. Resetting of the roller pipe 2 into the clamping jaw is necessary, because during the shaping of the bulging portion 6 very large forces appear and an undesirable wrinkling in the region between the roller pipe and the conical portion 20 could appear. In the fourth drawing or rolling step the inwardly bulging portion 24 is formed which constitutes a transistion portion between frusto-conical shaped portions 20 and 22. The transition portion 24 serves to facilitate the initiating of the turning-in and bending-in process of the portion 4 so that its diameter corresponds to the inwardly bent onto itself portion 4 in the direction of the axle stump 10.

In the aforedescribed process the running roller consists of the running roller pipe 2 and the welded-on axle stump portion 10. This type of construction has been selected so that to permit the shaping despite the vast dimensional difference between the diameter of the roller pipe 2 and the diameter of the cylindrical end piece 18, which shaping can be carried out without a normal annealing process. In the event there exists the possibility for carrying out a normal annealing during the third drawing or rolling step, then obviously the entire running roller can be made of unitary construction without the necessity of welding on to it the axle stump portion 10.

In the aforedescribed and illustrated example there is welded, after the third drawing step, a cylindrical piece of pipe onto the bulging portion 6 so that the fillet weld 8 results. In the event a large number of rollers are produced it is of course understood that a circular welding machine is used in this step.

After the welding of the cylindrical pipe piece has occurred, the entire assembly is re-shaped between a fourth to an eighth drawing step so that the conical portion 12, the hexagonal portion 14, a further conical portion 16 and the cylindrical end piece 18 are finally shaped. It should be noted that in the eighth drawing step the hexagonal portion 14 is formed from a cylindrical piece that is situated between the frustoconical portions 12 and 16. The eighth drawing step also serves to calibrate the cylindrical end piece 18 and to exactly axially position it relative to the roller pipe 2, so that after the roller pipe 2 has again been reset into the clamping jaws the transfer region between the roller pipe 2 and the conical portion 20 is positioned within the clamping jaws, thereby the crimped portion 4 being ready to be drawn and shaped. This shaping process, as mentioned hereinabove, is facilitated by the inwardly bulging portion 24 which surrounds the entire periphery of the to be shaped pipe portion. Further, the resetting of the roller pipe 2 into the clamping jaws serves to avoid an exterior wrinkling which may appear due to the very large forces that are present in the shaping process, in particular in the crimping and turning inward step of the shaping process.

As can be noted there is produced in accordance with the process of this invention a running roller, which is fabricated without the usual accompanying production of chips and which corresponds in its dimension to those of the conventional running rollers and can be produced completely automatically.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of embodiments, but is capable of numerous modifications within the scope of the appended claims.