GB2026702A

GB2026702A - A Method for the Correction of Unbalance Present in a Rotary Body

Info

Publication number: GB2026702A
Application number: GB7917729A
Authority: GB
Original assignee: Avery Denison Ltd
Current assignee: Avery Denison Ltd
Priority date: 1978-07-08
Filing date: 1979-05-22
Publication date: 1980-02-06
Also published as: DE2830070A1; GB2026702B; DE2830070C2; IT1122038B; FR2434381A1; FR2434381B1; IT7924147A0

Abstract

A method for the correction of unbalance present in a rotary body involves applying material to or removing material from a number of correction sites around the body, the correction sites being determined or limited by structural features of the body, for example as in rotors or armatures of electric motors. The measured unbalance for a given correction plane is analysed into a number of separate components corresponding to a maximum of half and a minimum of two of the correction sides, each component being equivalent to an integral number of standard unit weights. <IMAGE>

Description

SPECIFICATION Method and Apparatus for the Correction of Unbalance Present in a Rotary Body This invention relates to a method and a device for the correction of unbalance present in a rotary body by applying or removing material.

In order to correct an unbalance present in a rotary body it is known to remove the unbalance by polar correction at the position where the unbalance acts, for example through removing material by drilling, or to form a correction vector corresponding to the unbalance vector, from which it is offset by 1 80C and effects correction of the unbalance by applying material.

It is also known to remove an unbalance vector by component balancing. In this case however components in fixed angular directions are provided to correct the unbalance. In addition large accumulations of material occur when for example the unbalance direction coincides with a component direction and if the amount of unbalance has the maximum value permitted for a given body. In such case it is frequectly not possible to correct the entire unbalance, since with rotors running in housings for example the distance between the end face of the rotor and the housing cover is so small that the correction body would damage the cover during rotation.

Also a different weight has to be used for each correction procedure, which necessarily involves considerable expense in the provision of a store or correction bodies (see "Precision dynamic balancing" in the Fine Machining series by Wolf Dieter Reutlinger, pages 73-4).

In component balancing it is also impermissible to divide the required correction material around the correction direction if it coincides with a component direction.

In polar balancing it is also known to effect correction of the unbalance effect by moving two equally large bodies, which must be equal to the maximum unbalance present (see "Precision Dynamic Balancing" in the Fine Machining series by Wolf-Dieter Reutlinger, DEVA Technical Publishers, 1-3 thousand 1957, (pages 75-6).

Although polar balancing, where possible, has certian advantages over component balancing, both balancing methods have the major disadvantage of material accumulations at specific points in the rotary body being balanced.

This also applies with what is known as quasipolar dynamic balancing, wherein the correction position nearest to the actual direction of the unbalance is utilised for correction. In addition all known dynamic balancing methods have the serious disadvantage that the maximum possible correction of a given unbalance with minimum use of material and considering the maximum permitted accumulation of material cannot be performed at one point in the rotary body.

Arising from this prior art the invention has undertaken the problem of providing unbalance correction which has the most uniform possible distribution of corrective masses at the possible correction sites. According to the invention this problem is solved in that in dependence on an unbalance vector, from all the possible correction points for an unbalance measurement plane a maximum of half and a minimum of two correction points corresponding to the unbalance vector are selected, at each of which a variable number, differing from zero, of standard unit weights may be applied to correct the unbalance.

The method according to the invention is especially marked by the possibility of distributing the correction weights around possible correction sites, and enables the unbalance correction to be optimised using correction weights made of a standard unit size.

In one particularly favoured embodiment of the invention, the selected correction points are not disposed in continuous sequence. With this embodiment provided by the invention it is also possible to make substantially full allowance for the angle of unbalance and the unbalance effect of a resulting correction vector.

A particularly effective device for performing the method, with memories disposed in a storage unit and matching members for the processing of an unbalance according to its position and magnitude is characterised by the provision of a classification unit for digital classification of the unbalance vector according to its components, by the provision of a memory unit for digital storage of the correction points with the number of unit weights corresponding thereto, in that the memory unit is firstly controlled with the values from the classification unit, in that the memory contents are secondly connected to a display unit on which every possible angular position for a correction plane and the maximum permissible number of unit weights can be indicated by display lamps, and in that the memory unit with the display unit can be connected to the current supply for the necessary number of display lamps.

The digital classification of the unbalance vector according to its components provides a clear relationship between the magnitude of the unbalance requiring correction and the unit weights for the correction.

The method in accordance with the invention may also be put into practice by a device wherein a storage unit includes memories and matching members for the processing of an unbalance according to its position and magnitude, and which is characterised in that there is provided a classification unit for digitally classifying the unbalance vector according to its angle and magnitude, in that an evaluation unit is provided wherein as the unbalance magnitude is increased the class width for the unbalance angle is reduced, in that a storage unit is provided for digitally storing the correction points with their corresponding numbers of unit weights, in that the memory storage unit is firstly controlled with the values from the classification unit, in that the memory contents are secondly connected to a display unit on which every possible angular position for a correction plane and the maximum permissible number of unit weights can be indicated by display lamps, and in that the memory unit with the display unit can be connected to the current supply for the necessary number of display lamps. A particular feature of this device is the provision of information on the most favourable number of correction points to select. The invention will be described in detail with reference to the attached drawing.

Measurements relating to the magnitude and angular position of unbalance and obtained in a dynamic balancing machine (not shown) are fed to an unbalance measuring device 1 where they are resolved into vertical and horizontal components 2, 3 and then fed to a rectifier unit 4, wherein absolute values for the vertical and horizontal components 2, 3 are formed, with allowance for the preceding positive or negative signs, so that the amounts for the vertical component 6 and horizontal component 7 can be fed separately to a classification unit 8. The sign present in rectifier unit 4 for the vertical component is fed via a lead 20 to a recording and reading storage unit 9, while the sign for the horizontal component is transmitted via a lead 21 to a sign unit 13.There the amounts for the vertical component 6 and the horizontal component 7 are digitally classified and delivered separately to a recording and reading storage unit 9 for the vertical component, with allowance for the sign, and a further recording and reading storage unit 10 for the horizontal component.

Finally the values prepared in this manner are jointly delivered to an addition unit 11, and from this to the input terminals of a storage unit 12, separately for the classified horizontal component and the classified vertical component Because of the separate actuation of the storage unit 1 2 by the classified horizontal and vertical values it is possible to select the possible correction points and the maximum permissible unit weights which are held in a matrix in the storage unit. The values thus selected and corresponding to the magnitude of unbalance are delivered, with allowance for their sign in a sign unit 13, via a lead 14 to a display unit 15 where they are displayed.The possible correction points on the test-piece are shown numerically in the display device 15 and the number of maximum permissible unit weights is displayed by lamps 1 6.

The display unit 1 5 thus presents a representation of the end face of the rotary body being balanced, showing both the angular position of the correction position through the numerical display, with the magnitude of the unbalance also made visible by lighting of the corresponding lamps 1 6.

Instead of the display unit 1 5 and the lead 14 may be connected to a stepping motor for rotating the test-piece being balanced, and also to feed means for unit weights to be applied to the end face of a rotor under test, so that with the information arriving via the lead 14 both the stepping motor and the feed means can be automatically controlled to effect the unbalance correction.

It is to be understood that the invention is intended for use with test bodies which per se have a definite number of connection sites, for example rotors or armatures of electric motors.

Claims

1. A method for the correction of unbalance present in a rotary body by applying or removing material, characterised in that in dependence on an unbalance vector, from all the possible correction points for an unbalance measurement plane a maximum of half and a minimum of two correction points corresponding to the unbalance vector are selected, at each of which a variable number, differing from zero, of standard unit weights may be applied to correct the unbalance.

2. A method as in Claim 1, characterised in that the correction points are selected in such a way that each selected correction point or at least some correction points are separated from the adjacent selection point(s) by at least one other correction point.

3. Apparatus for performing the method as claimed in Claim 1 or 2, comprising means for measuring the dynamic balance present in a rotary body, memories disposed in a storage unit and matching members for the processing of an unbalance according to its position and magnitude, characterised by a classification unit for digital classification of the unbalance vector according to its components, a storage unit for digitally storing the correction points with the number of unit weight sizes corresponding thereto, the storage unit being controlled by the values from the classification unit and being connected to a display unit on which each possible angular position, i.e. correction position, for one correction plane and the maximum permissible number of unit sizes can be displayed in analogue form according to the information contained in said storage unit

4. Apparatus for performing the method as claimed in Claim 1 or 2 with memories disposed in a storage unit and matching members for the processing of an unbalance according to its position and magnitude, characterised by a classification unit for digital classification of the unbalance vector according to its angle and its magnitude, an evaluation unit wherein, in accordance with the increase in unbalance magnitude, the class widths for the unbalance angle are reduced, a storage unit for digitally storing the correction points with the number of unit sizes corresponding thereto, the storage unit being controlled with the values from the classification unit and being connected to a display unit on which each possible angular position for one correction plane and the maximum permissible number of units can be displayed according to the information contained in said storage unit.

5. Apparatus as claimed in Claim 4 or 5 in which said display unit comprises a display grid on which the angular positions of the correction positions are indicated, each angular position being defined by a number of radially spaced indicator lamps or the like corresponding to different numbers of standard unit weights.

6. A method as claimed in Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.

7. Apparatus as claimed in Claim 4 or 5 substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.