DE19541026A1 - Permanent imbalance correction applicable alternatingly with profile correction - with partial melting and shifting of the tool material within a specified region close to the tool periphery - Google Patents

Abstract

The method for permanent imbalance correction involves use of at least one spark electrode (4) located on the right and left close to the outer rim of the tool (8), and an imbalance sensor (10) which measures primarily radial but also axial imbalances, and is connected to an electronic evaluation unit. Dependent on the imbalance thus detected, partial melting of the tool material is achieved by means of repetitive effect the electrode (4) so that a plastically deformable region (5) is formed. As a result of high centrifugal forces, the workpiece material within this region is shifted to a larger radius, and the imbalance is gradually corrected. Electrodes located on both sides are required to eliminate possible axial imbalance brought about by the effect of a single electrode. Balancing can be carried out at tool speeds in excess 100000 revolutions per min. Balancing is alternatingly combined with spark-erosive tool profile correction by the ELID (electrolytic in-process dressing) process. For this process the tool speed must be reduced to a value equal to 2 to 5 per cent of the working speed.

Description

Balancing methods such as removal of materials and also attaching balance weights on high-speed parts known.

From the patent DE 28 33 486 and the published patent application 2705217 is also a continuous balancing by materi al extraction at an unbalance-relevant point known. In addition to that in the first mechanical writing are also methods of Er melting and evaporation for material removal in the second Scripture described. Melting and especially evaporation mean a high energy input at a very limited Position of the rotor circumference. It is the highest energy density reachable with the laser or electron beam. Both metho They require a lot of equipment and volume. At high peripheral speeds (effective balancing can only be realized at operating speed!) requires the this additional expenditure of technology the energy density / time to increase. In addition, the removal means at one point to order balancing correction that a warming of the surroundings of the evaporate material is subjected to high centrifugal forces and a material shift of this plasticized material Removal of the material removed for unbalance correction hend ineffective, so that disproportionately removed must be to achieve the desired effect.

The present invention is intended to eliminate these disadvantages.

The removal of a volume at an unbalance-relevant point can be offset 180 degrees by attaching a weight replace.

You can also attach a weight in the same place replace by moving a weight to a height radius.

Exactly this weight shift is in the present invention, by melting a material point area with subsequently shifting of this melted by high centrifuge gas forces applied.

In the field of electrical welding there are non-melting wolves  Ram electrodes are known which cover the workpiece area of the ver is usually heated in a protective gas environment which is not absolutely necessary here. The melting of the unbalance-relevant point volume must be dosed so that none Evaporation occurs, there is already a considerable amount of energy energy savings justified. WSG welding are relative known simple welding electrodes that ge for this use are suitable.

The unbalance correction of a rotor that has been balanced once after its manufacture has to be repeated at all, is due to the occasionally required profile correction, which eliminates less worn areas of the tool geometry in order to restore the original profile. Of course, a constantly changing imbalance situation arises during tool wear and must be corrected if necessary. In contrast to profile correction, the unbalance correction can be carried out at operating speed. A zero radial imbalance, the force component of which is perpendicular to the axis of rotation, must be carried out with a correction on both sides of the disk 8 . Unilateral treatment will also produce an axial component, which of course also means that existing axial imbalance can be eliminated by unilateral treatment. Therefore, measurement by the accelerometer 10 is also required in the axial direction. The intensity of the two opposite correction values is controlled in a differentiated manner and thus also eliminates an existing axial imbalance.

The highest form of profile correction is the ELID procedure (electrolytic in-process dressing). In this method, a liquid 11 - an electrolyte or a dielectric in EDM profile correction - is brought between the tool and the profile electrode 1 . Both methods require, already because of the air layer surrounding the disc, that the speed is reduced considerably. In addition, both processes take place in a time interval that requires a low peripheral speed. Because of these process conditions, they cannot be used as an unbalance correction at operating speed.

An embodiment is shown in Fig. 1 ( Fig. 2 and 3 enlargements of the tool areas with electrodes).

• 1 = profile electrode for ELID method or spark erosion method for profile correction.
• 2 = insulation from the opposite pole.
• 3 = electrode holder for the unbalance correction electrode on the right and left.
• 4 = Non-melting tungsten electrode for balancing on both sides simultaneously with pure radial unbalance
• - Different on both sides if there is one also axial unbalance.
• 5 = Imbalance compensation area right and left. This area can also be displaced radially by the eccentric design of the holder 3 .
• 6 = counter-pole electrode with direct contact for both processes, unbalance correction and profile correction.
• 7 = pressure spring. As a rule, this is to be replaced by a controlled pressure which also allows it to be lifted off.
• 8 = tool.
• 9 = workpiece.
• 10 = accelerometer as unbalance sensor. Also for axia le vibration measurement.
• 11 = dielectric or electrolyte.
• 12 = melted and shifted balancing material.

Claims (1)

Permanent, time-limited imbalance correction, which can be used alternately with profile correction, characterized in that at least one melting spark electrode ( 4 ) is attached to the outer edge on the right and also on the left, by an unbalance sensor ( 10 ), which at least one unbalance direction is primarily radial but also radial the second unbalance plane is detected axially and, via an electronic evaluation unit at a point ( 5 ) corresponding to the existing unbalance, in at least one revolution of the tool, but as a rule several times a partial melting of the tool material into a plastically deformable area by arc energy transmission, which acts again by high centrifugal forces causes a material shift ( 12 Fig. 3), which eliminates the existing unbalance with permanent actual value monitoring by the sensor ( 10 ), which has to happen on both sides at the same time if it is only a radial unbalance - since a one However, axial treatment creates an axial imbalance, but can also eliminate it - the arrangement on both sides is necessary in order to be able to carry out a differentiated application on both sides in connection with the measurement of the axial imbalance to eliminate axial imbalance, this occurs at the working speed in generally <100,000 rpm, since a dielectric or electrolyte for ELID ( 11 ) is placed between the tool and the profile electrode ( 1 ) for the EDM profile correction, the speed must be reduced to about 2-5% for this profiling process, This is one of the reasons why the disc comes to a more or less static runout, which is necessary as a first prerequisite for a dynamic runout.