Patent Application
20130167609
The invention relates to a machine, in particular a machine tool, for deep rolling wheelset shafts for rail vehicle wheelsets with two prick punch points for holding a wheelset shaft at its respective ends, a device for driving the wheelset shaft, two pairs of crankshaft deep rolling tools, which can be moved in directions x, y and z of the machine tool for machining the axle journal for the wheelset shaft, and with clamping and feed devices for the crankshaft deep rolling tools.
A “stamping wheel for burnishing shaft parts, particularly the axle journal and wheelset fail-safes” is known from the German patent document no. 808 197. The working surface of the stamping wheel consists of one cylinder, to which, on the one hand, a large rounding for the large corner groove of the axle journal and, on the other hand, a small rounding for the small corner groove on the axle collar are connected. The axle for the stamping wheel is supposed to adopt a skewed position to the axle of the axle journal during the burnishing procedure and, when pressed into the axle journal at one position, create a long, drop-shaped imprint on the surface of the axle journal.
At the time the above-mentioned German patent was registered, deep rolling was called “burnishing”. A company brochure of the applicant from 1954 then shows a machine which can be used to deep roll the two axle journals on a wheelset from their respective outer ends. Only the axle journals of finished wheelsets were machined respectively. To do this, two pairs of work rollers were used which were each meshed simultaneously onto the axle journals for the wheelset. In those days, the wheelset was driven via a transmission belt, which was looped around one of the two wheel discs for the wheelset. With the known machine, the axle journals for the wheelset were rigidified to such an extent that, along with having an improved surface quality, they also had simultaneous higher strength, whereby hot axle boxes were able to be prevented on the one hand and axle journal breakage on the other. The known deep rolling operation therefore meant that internal stresses were introduced into the surface of the axle journal which led either to no cracks being produced or cracks that were already produced being able to be brought to a stop. The outcome was that an increase in the service life of the wheelset was achieved.
As well as the treatment of the axle journal, a “device for burnishing cylindrical workpieces like shaft parts” is already known from the German patent document no. 843 922. The known device features one or more work rollers, whereby each work roller is mounted in a pivoting carrier whose swivel axis runs both vertically to the infeed motion of the work roller and vertically, or nearly vertically, to the workpiece axis. The known device was supposed to be used mainly for machining cylindrical shafts, which does not rule out that it could be used for deep rolling wheelset shafts, too.
Damage to the wheelset shafts of railway high-speed vehicles which has recently occurred has led to particular attention being paid towards the finishing of the wheelset shafts. In doing so, the formation of cracks in particular is to be counteracted.
On the basis of the knowledge that by introducing residual compressive stresses into the surface of crankshafts, the formation of cracks can be prevented or cracks that have already occurred can be brought to a stop, the task of this invention is now to propose a modern machine which can be used to deep roll the wheelset shafts of wheelsets for railway vehicles before the wheel discs are fitted. As is well known, a wheelset shaft is characterised in that it features several adjacent lengthwise sections (hereinafter referred to as axle zones) with different diameters.
In a machine tool of the type specified, this invention means the task is solved by having tools that comprise more than two pairs of work rollers, of which each pair is intended for deep rolling at least one axle zone on the wheelset shaft. In a favoured variant, the tools comprise two times three pairs of work rollers.
Here, it is intended that the first pair of work rollers be used to deep roll the axle journals and transition piece, a second pair of work rollers to deep roll the press seating for one wheel disc and a third pair of work rollers to deep roll the stub shaft from the press seating at least up to the longitudinal centre of the wheelset shaft.
Ideally, the work rollers forming the first and second pair are each arranged together in one housing. This housing can be moved in the y-direction of the machine tool. Owing to the movability in the y-direction, the work rollers for the first and second pair of work rollers are meshed one after the other. At the same time, the housing can be pivoted around a B-axis of the machine tool. This movability makes it possible to machine the transitions between the individual axle zones of the wheelset shaft. As is well known, the transitions are arranged as corner grooves.
The first and the second pair of work rollers are at a specified fixed axial distance away from the third pair of work rollers in the z-direction of the machine tool. All three pairs of work rollers are ultimately arranged together on one slide. The common slide can be moved in the z-direction of the machine tool, i.e. in the feed direction. Two slides in total are provided on the machine tool, each of which is designated to the respective end of the wheelset shaft. When the axle zones are deep rolled, the two slides move towards each other at feed rate.
Ultimately, the crankshaft deep rolling tools can also be adjusted in the x-direction. A servo motor is used to feed in two work rollers, each forming one pair, in the direction of the wheelset shaft at the same time. Notably, all three pairs of work rollers are moved at the same time. The deep rolling force is also set via the infeed in the x-direction.
The invention is described in detail below using a design example. The following views are illustrated at a reduced scale
Wheelset shaft 5 on a wheelset (not shown) consists of several axle zones. Axle zone 1 represents the axle journal. Upon which the wheelset is rotatably mounted in the rail vehicle. In the direction towards the longitudinal centre 6 of the wheelset shaft 5, axle zone 2 follows axle zone 1. Axle zone 2 forms the transition between axle zone 2 and axle zone 3 and is formed through a corner groove 7. Axle zone 3 forms the press seating for a wheel disc (not shown) of the wheelset. Axle zone 3 is followed by axle zone 4, which has a considerably smaller diameter when compared with axle zone 3. Axle zone 4 stretches up to the longitudinal centre 6 of the wheelset shaft 5, upon which identical axle zones 4, 3, 2 and 1 follow to the other end (not shown) of the wheelset shaft 5.
Axle zones 1 to 4 for the half of the wheelset shaft 5 shown are machined by the first slide 8 for the machine tool 9, while the axle zones 4 to 1 on the other half (not shown) of the wheelset shaft 5 are worked on by a second slide 10 for the machine tool 9. At the same time, the two slides 8 and 10 work towards each other in the direction of the longitudinal centre 6 of the wheelset shaft 5, each starting from the axle zones 1.
On machine bed 11 for machine tool 9, one headstock 12 and one tailstock 13 are initially arranged so that they can be moved longitudinally in the z-direction. The first slide 8 is upstream of the headstock 12 in the z-direction, and the second slide 10 is upstream of the tailstock 13 and can also be moved in the z-direction. The two slides 8 and 10 can be moved in the z-direction at feed rate, independent of their respective headstock 12 or tailstock 13. A second headstock, which is designed in exactly the same way as the headstock 12 shown, can also be provided in place of tailstock 13. The design of headstock 12 will be dealt with in the following.
The headstock 12 shown in
By contrast, the work roller 15 rotatably mounted in housing 37 in slide 10 is provided with a counter-roller 14 for the purpose of machining the axle zones 3 and 4 on wheelset shaft 5. The work rollers 14, 15, 23 to 26 are not driven but are set in rotation by the driven wheelset shaft 5. The drive units 28 and 29 are used to pivot the work rollers 23 and 24 or 25 and 26 around the B-axes. Two further drive units are used to move the work rollers 23, 24 or 25, 26 vertically in the y-direction,
A spindle drive 30, which is specifically shown in
In the machine's z-direction, the work rollers 14, 15, 23 to 26 for the two slides 8 and 10 each have a fixed distance 43 away from each other. This means that housing 27 and the carriers 34 and 35 each have specifically fixed lateral distances away from each other. As a consequence, spindle drive 30, which is shown in
At the start of the deep rolling operation, the work rollers 23 and 25 roll the axle zones 1 and 2, whereby they are each pivoted around the B-axis for machining the transitions 7 and 41. At the same time, the work rollers 14 and 15 roll the start 42 of axle zone 4. After the axle zones 1 and 2 have been deep rolled, the work rollers 23 and 25 are disengaged by shifting in the vertical direction (y-direction) and the work rollers 24 and 26 become meshed. The work rollers 24 and 26 then roll the axle zone 3, where the press seating is located between the wheelset shaft 5 and the wheel disc. At the same time, the work rollers 14 and 15 continue to machine axle zone 4 in the direction towards the longitudinal centre 6 of wheelset shaft 5.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE2010/000771 | 7/1/2010 | WO | 00 | 3/18/2013 |
