Erwin Junker Maschinenfabrik Gmbh

Erwin Junker Grinding Technology A.s.

Bsh Holice A.s

Hubert Mueller

Georg Himmelsbach

Erwin Junker

Disclosed is a grinding tool () for highly accurate centre-less grinding in continuous process for shaft-like workpieces (), comprising at least one conical () and one cylindrical grinding region (). With its first grinding cover (), the conical grinding region () is primarily intended for grinding larger cutting volumes, whereas the cylindrical grinding region (), with its second grinding cover () is primarily intended for achieving the highest surface quality, without, in the case of the latter, having to remove large cutting volumes. The grinding covers () differ at least in respect of the grinding agent used, CBN preferably being used in the conical region and diamond being used in the cylindrical region. Further disclosed is a method, which works with the grinding tool () as per the invention and which grinds the shaft-like workpieces (). Oversize and surface quality are at least temporarily simultaneously ground.

Method and grinding tool for highly accurate centre-less grinding of shaft parts with high surface quality

On a workpiece there are first longitudinal portions which are rotationally symmetrical with respect to the continuous longitudinal axis and are intended to be ground by way of centerless grinding. The workpiece also has a second longitudinal portion, which is not rotationally symmetrical with respect to the longitudinal axis and would lead to imbalance in the event of rotation. Therefore, a balancing weight having a radially extending recess is placed on the second longitudinal portion. The balancing weight contributes largely to uniform distribution of the rotating masses, thus reduces the imbalance to a very low residual imbalance and allows reliable and precise centerless grinding.

Method for the cylindrical grinding of a workpiece, system containing the workpiece and apparatus for the centreless grinding of the system

In a method for the hydrodynamic support and centering of a rotating workpiece during grinding and a steady rest usable for this purpose the bearing to be supported is impinged upon by a contact pressure which changes in accordance with rotational speed from a minimum pressure when the shaft is started from a standstill, to a maximum value during the processing rotational speed. The steady rest has an opening of a transversebore in a central bore receiving a supply line by which a lubricant can be supplied as hydraulic fluid to the bearing. The method is particularly suitable for the processing of camshafts and crankshafts.

Method for the support of a rotating workpiece during grinding and a hydrodynamic steady rest

In an indexable insert having wide sides, inclined narrow sides are to be ground, that is to say the grinding allowanceis to be removed. To this end, the indexable insert is set in rotation about a driven axis of rotation between a clamping insert and a thrust bolt. Serving for the grinding is a grinding wheel which rotates about rotation axis and which has a circumferential surfacecontoured in a circular shape and having a largest diameter and is composed of a leading region and a trailing region. The grinding wheel is guided relative to the indexable insert along the geometrical defining line which is formed by the generating line of the finished narrow side in the feed direction. The leading region tapering forwards effects preliminary grinding of the narrow side by longitudinal grinding, whereas the trailing region effects finish grinding by linear contact with the narrow side. The grinding wheel is held with the clamping flanges on a grinding spindle. The grinding operation is effected with controlled movement of the driven axis of rotation, a first displacement axis, a second displacement axis and a pivoting movement of the grinding wheel relative to the indexable insert according to double arrow.

Method of grinding an indexable insert and grinding wheel for carrying out the grinding method

In order to grind bar-shaped workpieces which have a non-circular cross-section and flat faces which are parallel to each other, two partial operations are performed consecutively. First, the bar-shaped workpiece is rough ground and finished on the faces by way of double-disk face grinding. The bar-shaped workpiece is clamped on the longitudinal sides in the first clamping position thereof, and the bar-shaped workpiece is transported between two clamping jaws, which clamp the workpiece in the second clamping position thereof on the faces. The first clamping position is then released, and the bar-shaped workpiece is rotated by the clamping jaws. A CNC-controlled peripheral grinding step is performed based on CX interpolation principles. This rough grinds and finishes the longitudinal sides of the bar-shaped workpiece. Transport from the first to the second clamping position is effected by a clamping station, which concomitantly forms the holder for the face grinding operation.

Growing community of inventors

Nordrach, Germany

Hubert Mueller