WO2016020220A1

WO2016020220A1 - Method for reducing or eliminating imbalances of electrical machines

Info

Publication number: WO2016020220A1
Application number: PCT/EP2015/067192
Authority: WO
Inventors: Andreas Braun
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2014-08-04
Filing date: 2015-07-27
Publication date: 2016-02-11
Also published as: DE102014215275A1; CN106537738A

Abstract

The invention relates to a method for reducing or eliminating imbalances of electrical machines, wherein, after assembly, the electrical machine is inspected for position- and dimension-related imbalances, and these are balanced by changing the mass distribution and/or the mass in at least one end section (3) of a shaft (2) of the machine, in accordance with the determined values. The focus of the invention is the local removal of material and/or the useful addition of additional material that adheres in a materially bonded manner, in accordance with the determined imbalances, wherein the corresponding processing can be carried out on the end face and/or on the circumference of the shaft (2) in the end sections (3) thereof. Alternatively, according to a further method of the invention, a compensation body can be secured directly on the end section (3) of the shaft (2) in a receiving means provided for this purpose.

Description

description

Method for reducing or eliminating imbalances of electrical machines

The invention relates to a method for reducing or eliminating imbalances of electrical machines, in which the electrical machine is examined after its assembly on the position and dimension of existing imbalances and these depending on the values determined by changing the mass distribution and / or mass in at least one end portion be compensated for a wave of the machine.

A method and a device for reducing or eliminating imbalances of a machine shaft are already known from EP 1 740 919 B1. This document shows a device for balancing an imbalance of a shaft of an aircraft engine, comprising a coaxially attachable to a front end of the shaft round plate with holes axially therein, in which connecting means such as screws are introduced in order to provide the plate thus with balancing weights can , The document further describes a method for compensating an imbalance of a shaft of an aircraft engine, in which first a rotational imbalance of the shaft is monitored or detected and then accessed on a mounting plate on the shaft to at least one previously selected connecting means on the

Attach mounting plate and thus add a balance weight plate. Here, the selectable connecting means have identical diameters and different lengths.

It is also known from US 5,235,228 A an electric motor with a rotating output shaft, at the ends of disc elements are mounted with threaded holes on its axially outer surface, with balancing screws of different lengths in the

Threaded holes can be fixed and exchanged depending on the existing imbalances. According to a preferred embodiment, no additional disc elements are mounted, but already existing body on the shaft, such as the gear of a rotary encoder or a labyrinth seal, provided with the threaded holes.

Preferably, the threaded holes are arranged at equal radial distances from the axis of rotation of the output shaft. A disadvantage of the above-mentioned prior art has been found that a general additional processing, material and / or assembly costs for the

Provision or preparation of the mounting plates or disc elements described already arises before the machine has ever been examined for imbalances. Furthermore, according to the aforementioned balancing principles, no continuous adaptation of the mass or the mass distribution as a function of the measured imbalances is possible, so that only an approximate balancing by the use of the already prepositioned recordings in the plates or discs and by the choice of vorzuhaltenden in different versions Balancing compounds such as standard connection means can be done.

Against this background, the invention has the object, a method for

Reduction or elimination of imbalances of electrical machines to allow a more precise balancing of the machine with greater consideration of actually existing imbalances while reducing the material, storage, processing and assembly costs is possible.

This object is initially achieved with a method for reducing or eliminating imbalances of electrical machines according to the features of claim 1. The dependent claims 2 to 5 relate to particularly expedient developments of the invention.

According to the invention, therefore, a method is provided, in which in the at least one end portion of the shaft frontally and / or peripherally a cutting or abrading removal of material from the end portion and / or peripheral side additional material materially insoluble with the at least one end portion is connected. There are many advantages to using this approach. On the one hand there is a

Change in the shaft mass or its mass distribution in principle only after detection of at least one actually existing unbalance, so that in a shaft that rotates in the machine with a tolerable or nonexistent imbalance, no interference with the machine or wave structure must be made. On the other hand, the cost of materials for reducing or eliminating the imbalance is minimized because no additional support body is mounted, which surrounds the shaft circumferentially and thus also at positions where no balancing mass is required, is present. Thus, compared to the prior art, a weight saving can be achieved. Furthermore, the change in the shaft mass or its mass distribution is targeted and minimal to the extent of the required processing, as equally by cutting or erosive methods and by the dosage of a cohesively adhering additional material a fine-tuning of the mass removal or -zugäbe can be made to the existing imbalance.

The basic procedure according to the invention is therefore to examine the electrical machine after its assembly or of course at any later time of its use with sufficiently described in the prior art resources on existing dynamic imbalances, locate them and determine their quantitative size and starting from the Measurements the position, type and strength of a corresponding

To determine countermeasure, this countermeasure preferably takes place in an easily accessible end portion of the shaft body. In this case, this countermeasure can mean, for example, the removal of material, for example boring, milling or grinding (machining), alternatively removal by means of thermal processes such as laser cutting or laser drilling (abrasive machining). Likewise, the targeted application of a materially permanently adhering additional material, for example by the application of welding or adhesive points, already the

obtain desired fine-level compensation of the existing imbalances.

Here, the processing can be done equally on the peripheral surface as well as on the end faces of the shaft in the intended end portions, depending on how it requires the position or direction of the existing imbalance or in dependence of

existing space in the machine for handling the tools required for machining.

In order to allow an even more precise balancing machining of the shaft, it is provided according to the invention, the shaft mass targeted at both end portions of

Change shaft body. As a result, also in an advantageous manner

Balance in the longitudinal direction of the shaft considered and optimized.

A relief in the machining of the shaft body to reduce the imbalance can be achieved that a certain additional mass is already provided on the shaft body in the manufacturing process, so that, for example, possibly occurring errors in the machining of the shaft can be easily compensated as well as rough and strong imbalances can be resolved without too much interference in the actual rotational mass of the shaft. For this purpose, on the one hand, the shaft with a

Excess material, so for example a larger diameter or a greater length, made in the intended end for the balancing machining sections be made on the surface condition of these sections lower requirements. On the other hand, it is of course also possible to add a body of the same or a different material to the shaft. This mass body can be arranged on the front side or the shaft circumferentially enclosing this and connected to it, for example by welding, screwing or shrinking.

An advantageous development of this embodiment is given when the mass body is formed eccentrically and is positioned in a particular determined in dependence on the existing imbalances angular position, in particular releasably on the shaft. This reduces the processing effort, since a part of the existing imbalances is already compensated by the eccentric mass distribution on the shaft. By a releasable attachment, such as screw or clamp connection, the mass body with the shaft, the angular position of the eccentric portion of the mass body can be adjusted at any time and preferably continuously to a measured imbalance.

As a particularly practical embodiment of the method has been found that a particularly clean and precise removal of material from the shaft or the mass body by means of thermal ablation methods such as flame cutting, laser cutting or laser drilling method is made possible. Since the processed material evaporates in the thermal process and thus hardly or no chips occur, eliminating a cleaning of the electrical machine of separated material particles. In addition, due to the strong focusing of the applied energy in laser processing methods, there is a nearly punctiform change of the existing mass and thus a precise correction of even the smallest imbalances.

The object is further achieved by a method for reducing or eliminating imbalances of electrical machines according to the features of claim 6. The dependent claims 7 to 10 relate to particularly expedient developments of the invention.

According to the invention, therefore, a method is provided in which at least one

Balancing body is fixed in at least one receptacle of the at least one end portion of the shaft. In this way, an easy to implement method for changing the mass or the mass distribution is provided directly on the shaft body, the focus not in the selection of a suitable compensation body based on its dimension and mass, but in a positioning of a preferably initially contourless or shapeless mass at or in which at least one end portion is located. This will turn an economic Technology provided, which is applied only in the presence of an actual imbalance, achieved with a low leveling compound without any support body on the shaft the desired result and in which not numerous different balancing body must be kept. The at least one compensating body according to the invention is arranged directly where, according to the measured imbalances, a mass change is required, and can preferably be arranged in any position or angular position.

The at least one compensating body can in turn be positioned on the one hand in an eccentrically arranged receptacle on the end face of the shaft and / or on the other hand in a receptacle extending radially from the circumference to the axis of rotation of the shaft.

For this purpose, it has proven to be a particularly suitable variant to perform the recording as a radial, the axis of rotation of the shaft cutting through threaded hole and to secure the externally threaded compensating body partially or with its entire length in the bore. For example, for this purpose, the compensation body can be designed as a threaded pin and rotated by means of a commercial screwdriver in the determined required balancing position. This simple and quick to implement embodiment allows by changing the screwing a stepless fine adjustment to compensate for the existing imbalances and also offers a captive attachment of a compensation body.

In a further promising embodiment, the compensation body can be secured by an adhesive connection in the receptacle. This variant brings with it an advantageous vibration damping, electrical insulation and low installation costs.

The receptacle for the compensation body can in principle be introduced as an item in the production of the shaft in this. An even more precise arrangement of the

Compensating body, however, is made possible according to a variant in which the receptacle for the compensating body is introduced only after the examination of the machine on imbalances in the shaft. As a result, the total effort for the case that there are no imbalances, minimized and also can be determined based on the measured imbalances first, the optimal position and spatial extent of the recording.

Finally, it has proven to be practical to complete the method according to the invention by a frontal and / or peripheral arrangement of a detachable cover or a sleeve on the at least one end section of the shaft after its machining. One Such cover or a corresponding sleeve provides additional captive securing for the assembled balancing body and may optionally be filled with a vibration-damping material to counteract a possible noise of the balancing body at increasing speeds of the machine. As mounting options, a screwing the lid or a keyway with the shaft offers to the accessibility of the end portions of the shaft for a possible at any time

Balancing procedure to ensure.

The invention allows numerous embodiments. To further clarify its basic principle, one of them is shown in the drawing and will be described below. This shows in

Fig. 1 is a sectional view of an electric machine with a shaft;

FIG. 2 shows a front view of an end face of the shaft machined according to the invention; FIG.

Fig. 3 is a front view of an end face of the processed according to a variant of the invention shaft;

Fig. 4 is a front view of a front side of the with a through hole and a

Compensating body provided shaft;

Fig. 5 is a front view of a front side of the eccentric mass body

provided shaft.

FIG. 1 shows a sectional view of an electric machine 1 with two shafts 2.

According to the invention, the electric machine 1 is examined for its position and dimension of existing imbalances after assembly and these are compensated depending on the determined values in at least one end section 3 of the shafts 2 of the electric machine 1, in at least one end section 3 of the shafts 2 frontally and / or peripherally a cutting or erosive removal of material from the end portion 3 takes place and / or end face and / or peripheral side additional material materially inseparable from the at least one end portion 3 is connected. After completion of the balancing process, the at least one machined end portion 3 thereof is provided with a lid 12 enclosing this end and periphery. Figures 2 and 3 illustrate embodiments of the invention

Method and in each case show a plan view of the front side of a machined to reduce or eliminate imbalances in an end portion 3 shaft 2 of the electric machine 1. Thus, a first way to reduce the mass in the end portion 3 by the targeted introduction of with respect to the axis of rotation 6 of the shaft 2 radial holes 4. The required depth and the diameter of the radial holes 4 has previously been determined based on the existing imbalances. As a further possibility for reducing the mass in the end portion 3, the introduction of axial, that is to the axis of rotation 6 of the shaft 2 largely parallel holes 5 of different depth and different diameters is possible. Of course, in addition to drilling other methods

mechanical and thermal separation processes for local removal of the material possible. As a further example, FIG. 3 shows a shoulder 8 introduced by milling into an end section 3 of the shaft 2, which serves to compensate for a more pronounced imbalance. To illustrate an example of a cohesive application of a filler material, a weld point 7 is shown in Figure 2, which locally increases the mass of the shaft 2 at its periphery and thus can counteract an imbalance.

FIG. 4 shows a plan view of the end face of a shaft 2 of the electric machine 1 machined in an end section 3 for reducing or eliminating imbalances according to a further inventive method. The figure shows a receptacle 9, in this case a through-hole through the entire cross section of the shaft 2. The receptacle 9 is designed in this embodiment as a threaded bore. In the receptacle 9, a compensation body 10, here a threaded pin, screwed according to the invention, which complements the mass distribution of the shaft 2 depending on the position in the receptacle 9 in an advantageous manner such that an existing imbalance is balanced by the balance weight. For this purpose, the compensating body 10 can be sunk completely in the receptacle 9, but also be screwed in or out as far as the direction of the arrow 13 so that it protrudes beyond the circumference of the shaft 2.

Finally, FIG. 5 shows a plan view of an end face of the shaft 2 in an end section 3, wherein an eccentric mass body 1 1 is arranged non-rotatably on the circumference of the shaft 2. The mass body 1 1, for example, by a screw detachably connected to the shaft 2 and can depending on the position of detected imbalances in different

Angular positions are fixed on the shaft 2. With this embodiment, a simple and quick to implement and infinitely customizable way to change the

Mass distribution of the shaft 2 provided. LIST OF REFERENCE NUMBERS

1 electric machine

2 wave

3 end section

4 radial bore

5 axial bore

6 rotation axis

7 spot weld

8 paragraph

9 recording

10 compensation body

1 1 mass body

12 lids

13 arrow direction

Claims

claims

1. A method for reducing or eliminating imbalances of electrical machines (1), in which the electrical machine (1) is examined after installation on the position and dimension of existing imbalances and these depending on the values determined by changing the mass distribution and / or the mass in at least one

End portion (3) of a shaft (2) of the electric machine (1) are compensated, characterized in that in the at least one end portion (3) of the shaft (2) frontally and / or peripherally a cutting or erosive removal of material from the End section (3) takes place and / or front and / or peripheral side additional material

cohesively non-releasably connected to the at least one end portion (3).

2. The method according to claim 1, characterized in that in both end portions (3) of the shaft (2) at the front and / or circumference a cutting or erosive removal of material from the end sections (3) and / or forehead and / or Peripheral additional material is materially connected to the end portions (3).

3. The method according to claims 1 or 2, characterized in that one or both end portions (3) of the shaft (2) already during assembly of the electric machine (1) has a radial or axial extension in the form of excess material and / or one with having the shaft rotatably connected mass body (1 1).

4. The method according to claim 3, characterized in that the mass body (1 1)

is formed eccentrically and in a determined depending on the existing imbalance angular position is releasably positioned on the shaft (2).

5. The method according to at least one of the preceding claims, characterized in that as ablative process, a flame cutting or laser cutting or -bohrverfahren is performed.

6. A method for reducing or eliminating imbalances of electrical machines (1), in which the electrical machine (1) is examined after installation on the position and dimension of existing imbalances and these depending on the values determined by changing the mass distribution and / or mass in at least one

End portion (3) of a shaft (2) of the electric machine (1) are balanced, characterized in that at least one compensating body (10) in at least one receptacle (9) of the at least one end portion (3) of the shaft (2) is fixed.

7. The method according to claim 6, characterized in that the receptacle (9) of the

at least one end portion (3) of the shaft (2) designed as a through-threaded bore and the compensating body (10) provided with an external thread is fixed partially or with its entire length in the receptacle (9).

8. The method according to claim 6 or 7, characterized in that the compensating body (10) is fixed by an adhesive connection in the receptacle (9).

9. The method according to claim 6, characterized in that the receptacle (9) for the compensating body (10) is introduced only after determining the position and dimension of existing imbalances and in dependence of the determined values in the shaft (2).

10. The method according to at least one of the preceding claims 6 to 9, characterized

characterized in that the at least one end portion (3) after its processing frontally and / or peripherally enclosed by a cover (12) or a sleeve.