DE102012007871B3 - Method for transmission of electric power from stator to rotatable device carrier for e.g. drilling machine, involves constructing parallel structure for feeding power during occurrence of interfering force such that force is compensated - Google Patents

Abstract

The method involves constructing a parallel structure for feeding power by an energy feeding unit (3) during occurrence of interfering force such that the interfering force is compensated. A rotatable device carrier (2) is rotatably mounted on a mechanically fixed base part (1) around a rotational axis (5). The energy feeding unit is provided in the base part above coils. An energy coupler (4) supplies a device on the carrier via other coils, which are guided through a hollow shaft or a hole on the carrier. The device carrier is guided by a bearing (6).

Description

Problem:

Many machines for material processing are structured as follows:
On a fixed base (stator) a rotatably mounted equipment carrier is mounted on which the actual processing machines such as drilling-grinding and milling machines, etc. are located.

The material to be processed is fed via the fixed base (stator), which is then processed simultaneously with many machines mounted on the equipment carrier at the same time.

On the rotatable equipment carrier an electrical power in the 100 kW range and above is needed to supply these work machines, which is supplied via the fixed base (stator) to the movable equipment carrier. This performance is not constant, but depending on the current operation, strongly changing.

For the electrical supply of the machines on the equipment carrier mainly slip rings and energy chains are used as a bridge between the base and equipment carrier.

Both techniques have major disadvantages: With the slip rings it is the wear, with the energy chains it is both the wear and the fact that after each work cycle the equipment carrier must be reduced.

In this patent, a principle and a method will now be described with which contact-free arbitrarily high electrical power can be transmitted to the equipment carrier, and in such a way,
that neither torque nor forces are exerted by the power transmission from the base to the movable equipment carrier.

State of the art:

According to DE 10 2005 009 866 B4 a method is described in which three-phase current is fed into the device carrier, without thereby creating a rotating field. Forces in the axial direction do not occur due to the design.

In DE 199 53 583 C1 describes a method in which three-phase current is fed into a movably mounted part by concentrically arranged coils to the rotational axis, however, traveling waves occur, which can be effective in the axial direction forces.

From the DE 102 03 651 B4 Inductive transformers for energy transmission via coils are known, which are arranged in the axial direction opposite one another so that they are suitable for the transmission of alternating current from a fixed base part to a rotatable part. A disadvantage of this type of transformer is the fact that during the energy transfer power-dependent electromagnetic axial forces arise.

In DE 10 2006 044 704 A1 A method is described with concentrically arranged coils, in which the axial forces are compensated, but the method is only suitable for three-phase.

The new procedure:

It describes a basic principle and a concept for the contactless transmission of electrical power from a normally fixed base (the stator) in a rotatably movably mounted equipment carrier,
characterized,
that no torque or thrust forces are exerted on the movable equipment carrier by the electric power transmission. The principle is expandable to a plurality of bowl-shaped about an axis of rotation arranged against each other rotatable parts.

This new method differs considerably from the above known methods in that it is the description of a generally valid principle for the compensation of forces, namely the difference principle. This difference principle is frequently used in metrology [see: hut, 33rd edition, H Messtechnik], Springer Verlag, Berlin Heidelberg New York, ISBN 978-3-540-71851-2], but with a completely different direction.

Here the principle of difference is presented and applied in a special form:
For each power supply subsystem that generates a disturbing force, an infeed parallel structure that compensates for the disturbing force is installed, as a first approximation.

These force-compensating parallel structures require only force symmetry and no geometric symmetry.

• – Kräftefreiheit unabhängig von der aktuell zu übertragenden Leistung, der Phasenzahl, der Frequenz und der Kurvenform der Ströme und Spannungen.
• – Es können beliebig viele Phasen übertragen werden.
• – Es können gleichzeitig verschiedene Frequenzen übertragen werden.
• – Das Differenzprinzip kann auf Drehmomente übertragen werden, wie es beispielsweise in DE 10 2005 009 866 B4 bereits implizit gemacht wurde
• – Das Differenzprinzip lässt sich auch auf kapazitive Leistungsübertragung anwenden.

The following technique can be achieved:

• - Freedom of forces regardless of the current power to be transmitted, the number of phases, the frequency and the waveform of the currents and voltages.
• - Any number of phases can be transmitted.
• - Different frequencies can be transmitted simultaneously.
• - The difference principle can be transferred to torques, as for example in DE 10 2005 009 866 B4 already implicitly made
• - The difference principle can also be applied to capacitive power transmission.

Explanatory example

Two pictures show a special technical solution for energy transfer, which illustrates the difference principle in its application.

Figure 1 shows a mechanically fixed base part ( 1 ) on the itself; over stock ( 6 ) guided around the axis of rotation ( 5 ) rotatable device carrier ( 2 ) is located. The power supply ( 3 ) takes place from the outside via the coils Se in the base part ( 1 ), the secondary power extraction ( 4 ) for the supply of equipment to the equipment carrier ( 2 ) takes place via the coils Sa; It is guided through the hollow shaft shown or a separate hole on the equipment carrier. Not explicitly mentioned, but taken for granted, is the use of magnetically good conductive material for the magnetic circuits.

With a suitable circuit and correct dimensioning of the coils can now be achieved that the forces in the air gap Se1, Sa1 exactly compensate for the forces in the air gap Se2, Sa2. The Se and Sa do not have to be the same, but they can be different, for example, to the voltage transformation.

A slightly different geometry according to the same principle and with the same purpose is shown in Figure 2.

LIST OF REFERENCE NUMBERS

1

feststehender Basisteil (Stator)

2

drehbarer Geräteträger

Se_k

Spulenkörper primär, k = 1, 2

3

Energieeinspeisung

Sa_k

Spulenkörper sekundär, k = 1, 2

4

Energieauskopplung

5

Drehachse

6

Lager

zu Bild 2:

1

feststehender Basisteil (Stator)

2

drehbarer Geräteträger

Se_k

Spulenkörper primär, k = 1, 2

3

Energieeinspeisung

Sa

Spulenkörper sekundär

4

Energieauskopplung

5

Drehachse

6

Lager

to picture 1

1

fixed base part (stator)

2

rotatable device carrier

Se _k

Bobbin primary, k = 1, 2

3

power feed

Sa _k

Bobbin secondary, k = 1, 2

4

energy extraction

5

axis of rotation

6

camp

to picture 2:

1

fixed base part (stator)

2

rotatable device carrier

Se _k

Bobbin primary, k = 1, 2

3

power feed

Sat.

Bobbin secondary

4

energy extraction

5

axis of rotation

6

camp

Claims (2)

Method for transmitting electrical power from a base part ( 1 ) on one about a rotation axis ( 5 ) rotatably mounted equipment carrier ( 2 ), characterized in that for each disturbing force by electrical feed a parallel structure for feeding is constructed such that it compensates for the disturbing force of the feed. Method for transmitting electrical power from a base part ( 1 ) on one about a rotation axis ( 5 ) rotatably mounted equipment carrier ( 2 ), characterized in that one or more parallel structures are constructed such that the resulting force is compensated to zero for several disturbing forces by supplying electrical energy.

Images