Abrading – Abrading process – Roll – roller – shaft – ball – or piston abrading
Patent
1996-02-12
1997-10-28
Smith, James G.
Abrading
Abrading process
Roll, roller, shaft, ball, or piston abrading
451381, 451399, B24B 100, B24B 719, B24B 730
Patent
active
056812086
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method and an apparatus for grinding a crankshaft.
In the case of known methods, crankshafts are ground in a plurality of steps. In a first step, the main bearings of the crankshaft are pre-ground and, in a second, the lifting bearings. The grinding of the main beatings is finished in a third step. The central bearing and the crankpin are ground in a subsequent fourth step. In further steps, the grinding of the lifting bearing is finished (fifth step). In a sixth step, the crankshaft ends are machined and, in a final seventh step, the flanges of the crankshaft are ground.
In the case of apparatuses known as such, the crankshaft is clamped at its ends between the workpiece headstock and tailstock by means of chucks or by means of collets and spikes. Such a clamping of the crankshaft admittedly provides the required, secure mounting even at high rotational speeds. However, it is associated with the serious disadvantage that the crankshaft is exposed to axial forces, which lead to its deformation in the elastic range. This does not always result in damage to the crankshaft. However, quality and accuracy problems arise due to the elastic deformation, since the crankshaft springs back elastically after it is unclamped. A further disadvantage of these apparatuses lies therein that the chuck or collet covers parts of the crankshaft, which are to be ground, particularly flanges and central bearings. In order to be able to grind also these parts of the crankshaft, the chucks or the collets must be loosened from the crankshaft and the latter must be removed from the apparatus. Finally, these parts of the crankshaft must be ground in a separate step. The known method for grinding crankshafts therefore is exceedingly time-consuming and expensive.
In the German patent 727 220, a clamping apparatus for crankshaft grinding machines is described, for which the crankpins are clamped without axial pressure in clamping jaws seated on a pivotable segment. This segment can be pivoted about a pin, which is removed from the center of a face plate by a distance corresponding to the magnitude of the stroke. Moreover, further details concerning the mounting of the crankshaft are not given in this patent.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a method and an apparatus of the type, which enables the whole of the crankshaft to be ground in one clamping without or without significant axial forces.
The inventive apparatus is associated with a plurality of advantages. One significant advantage consists therein that the crankshaft, which is to be ground, can be clamped centrically between spikes, so that it does not deform in the axial direction. This advantage is supplemented by the further advantage that the whole surface of the crankshaft, in the planned clamped position in which it is free of axial pressure or under a slight, defined, axial tension, is accessible to the grinding tool, which comprises at least two separately mounted and appropriately contoured grinding disks.
The crankshaft is clamped into the apparatus, with a defined, slight axial tension and, so firmly, that it is held securely even at high rotational speeds. This is true also for crankshafts with eccentric parts of any mass. Due to the clamping under a defined, slight axial tension and without axial pressure, all the parts of the crankshaft, which are to be ground, are accessible to the grinding tool. Accordingly, the grinding of the crankshaft is completed with a single clamping.
The inventive apparatus is also not complicated technically and can be maintained easily.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages arise out of the following explanation of the invention by means of examples and the enclosed drawing.
FIG. 1 shows an apparatus with a clamped crankshaft,
FIG. 2 shows a partial section of the apparatus of FIG. 1 with a clamped crankshaft and a clamping element,
FIG. 3 shows a partial section through a further embodiment of the apparatus of FIG. 1 with a clamped crankshaft,
REFERENCES:
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patent: 3098328 (1963-07-01), Fournier
patent: 3581611 (1971-06-01), Lentz
patent: 3583108 (1971-06-01), Olishi et al.
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patent: 4932642 (1990-06-01), Salenbien et al.
patent: 5303511 (1994-04-01), Tsuchiya et al.
patent: 5392566 (1995-02-01), Wedeniwski
Banks Derris H.
Smith James G.
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