WO2009033573A1

WO2009033573A1 - Coupling device

Info

Publication number: WO2009033573A1
Application number: PCT/EP2008/007079
Authority: WO
Inventors: Zhidong Hua; Olaf Simon
Original assignee: Sew-Eurodrive Gmbh & Co. Kg
Priority date: 2007-09-10
Filing date: 2008-08-29
Publication date: 2009-03-19
Also published as: DE102007042659B4; DE102007042659C5; EP2201584B1; DE102007042659A1; EP2201584B2; EP2201584A1

Abstract

The invention relates to a rotary transmitter, wherein inductive coupling elements which transmit energy in a contactless manner, and also capacitive coupling elements for transmitting data in a contactless manner, are concentrically constructed with the rotational axis of the rotary transmitter, and wherein a magnetic shielding is arranged between inductive coupling elements and capacitive coupling elements.

Description

page 1

coupling device

Description:

The invention relates to a coupling device for a system for contactless energy and data transmission.

From DE 199 32 504 A1 an implementation of a contactless energy and data transmission of two mutually rotatable parts is known in which two or more coils are rotatably mounted, wherein at least one of the coils is in a half having an L-shaped cross-section ,

The invention has the object of developing a system with contactless energy and data transmission, the error rate of the transmission is reduced.

According to the invention the object is achieved in the coupling device according to the features indicated in claim 1.

Important features of the invention in the coupling device are that a first housing part and a second housing part are provided which are rotatably supported relative to each other about an axis, wherein a primary winding and a secondary winding form an inductive coupling element, wherein the primary winding on the first housing part concentric to the axis is arranged and the secondary winding is arranged on the second housing part concentric with the axis,

- An electrically conductive coupling surface is formed on the first housing part and on the second housing part an electrically conductive coupling surface is formed, which together form a capacitive coupling element. The advantage here is that the inductive coupling allows the power supply with large currents of constant frequency, while the capacitive coupling allows a low-distortion transmission of signal pulses for data transmission.

BESTATIGUNGSKOPIE Page 2

In an advantageous embodiment, a first pair of coupling surfaces and on the second housing parts, a second pair of coupling surfaces is formed on the first housing part, wherein each form a contact surface of the first pair with a contact surface of the second pair a capacitive coupling element. The advantage here is that the signal of the power transmission can not crosstalk to the signal of the data transmission. Thus, the transmission errors are reduced. Another advantage is that with the inductive coupling element large currents are transferable and thus a power supply is possible, while with the capacitive coupling elements data signals are transmitted with low amperage distortion.

In an advantageous embodiment, the inductive coupling element is surrounded by a magnetic shield. Preferably, the magnetic shield between inductive coupling element and capacitive coupling elements is arranged. Thus, the induction of eddy currents through the inductive transmission in the capacitive coupling elements is further reduced and there are sources of interference for data transmission away from the transmission range.

In an advantageous embodiment, the coupling surfaces are formed by metallic, annular bands whose surface is arranged in each case radially to the axis of rotation. Thus, the capacitive coupling elements are functional independently of the rotational position, because the electrical coupling surfaces simulate the rotational symmetry of the coupling device.

In an advantageous embodiment, the coupling surfaces of each pair are arranged on a common, imaginary cylinder. Thus, a compact size is provided.

In an advantageous embodiment, the turns of the primary winding and the secondary winding each extend about the axis of rotation. The advantage here is that the power supply is available regardless of the rotational position of the coupling device.

In an advantageous embodiment, the primary winding and the secondary winding are each connected to a plug which has a pull-out protection. Thus, a high current, for example, of more than 10 A, transferable, and the system has increased security. Page 3

In an advantageous embodiment, the inductive coupling element is arranged radially within the capacitive coupling elements. The advantage here is that the inductive coupling element with a small footprint is executable, and that the capacitive coupling can be realized inexpensively.

In an advantageous embodiment, each contact surface has a ring width of 1 cm to 3 cm, in particular 2 cm. Preferably, the coupling surfaces of each capacitive coupling device 0.5 cm to 2 cm, in particular 1 cm, spaced. Thus, particularly favorable conditions for data transmission are achieved.

In an advantageous embodiment, the coupling surfaces of the capacitive coupling devices each form an electrically conductive ring, which is electrically severed at one point. Thus, circulating eddy currents that would be induced in the capacitor surfaces of the capacitive coupling elements of the inductive coupling element, interrupted.

In an advantageous embodiment, the coupling surfaces of the capacitive coupling devices are each connected in the middle between the ends formed by the transection with connection means. Thus, a good data coupling is achieved.

In an advantageous embodiment, the coupling surfaces of the capacitive

Coupling devices in the circumferential direction transverse gaps or cuts. Thus, eddy currents that would be induced in the capacitor surfaces of the capacitive coupling elements of the inductive coupling element, further reduced.

In an advantageous embodiment, the coupling surfaces are each mounted on an electrically insulating pad. Thus, an undisturbed data transmission over the communication channel formed by the coupling surfaces is made possible.

Further advantages emerge from the subclaims. The invention is not limited to the combination of features of the claims. For the skilled person, further meaningful combination options of claims and / or individual claim features and / or features of the description and / or figures, in particular from the task and / or by posing the task by comparison with the prior art task. page 4

LIST OF REFERENCE NUMBERS

1 rotary transformer 5 2 housing part

3 housing part

4 connecting ring

5 connection box

6 plugs

10 7 Excerpt from arrears

8 BNC connector

9 Screw 10 WeIIe

20 primary winding 15 21 secondary winding

22 connection

23 shielding

24 air gap

25 ring insert

20 26, 27, 28, 29 copper strip

30 labyrinth seal

31 axis of rotation

32 primary winding

33 trough

25 34 secondary winding

35 carriers

36 lids

37 gap

38 area

30 40 copper strips

41 longitudinal stripes

42 horizontal stripes

43 gap page 5

44 end of the strip

45 incision 50, 51 modem

52, 53 transceiver 5 54 generator

55 AC / DC converters

56 primary side

57 Secondary side 58, 59 Capacitor

10 60 consumers 61 rotary joints

page 6

The invention will now be explained in more detail with reference to figures:

It shows

Figure 1 shows a rotary transformer according to the invention, - Figure 2 is a sectional view through the rotary transformer of Figure 1, Figure 3 is a sectional view through another rotary transformer, Figure 4a is a copper strip for a coupling element of a rotary transformer, Figure 4b shows another copper strip for a coupling element of a rotary transformer and FIG 5 shows the electronic block diagram of a rotary transformer.

FIG. 1 shows a rotary transformer 1 according to the invention. A first housing part 2 is connected by a connecting ring 4 to a second housing part 3. First housing part 2 and second housing part 3 are rotatable about the axis of the connecting ring 4 against each other.

On the first housing part 2 and the second housing part 3, a terminal box 5 is formed. At each junction box 5 is a plug 6 for power, ie for more than 1OA, formed and a BNC connector 8 for connecting a high-frequency line.

A hinged bracket on the plug 6 forms a pull-out fuse 7 for the plug of the power line.

First housing part 2 and second housing part 3 are made of plastic.

FIG. 2 shows an axial section through the rotary transformer according to FIG. 1.

The connecting ring 4 is connected by screws 9 with a hollow shaft 10. In this way, a bearing is formed, in which the first housing part 2 and the second housing part 3 are rotatably arranged.

The plug 6 is connected by leads, not shown, with terminals 22, which in turn are connected to the two ends of a primary winding 20. The windings of the primary winding 20 extend around the axis of rotation of the rotary transformer. Thus, an alternating current which is impressed on the plug 6 in the primary winding 20 generates Page 7

Magnetic field, which passes through a ring-shaped extending around the axis of rotation secondary winding 21 and induces a current in the secondary winding 21. The secondary winding 21 is fixedly connected to the second housing part and connected via terminals and not shown conductor with a not visible in Figure 2 connector 6. Primary winding 20 and secondary winding 21 have a common axis. Thus, the primary winding and the secondary winding form an inductive coupling element, and it is energy contactless inductively transmittable across the hinge. Between primary winding 20 and secondary winding 21, an air gap 24 is arranged, which allows the relative rotatability of the first and second housing part.

Primary winding 20 and secondary winding 21 are each of U-shaped in cross-section, annular-trough-shaped shields 23, whose openings are facing each other. Thus, the magnetic field generated by the primary winding and the secondary winding is included and substantially does not come out of the annular region enclosed by the shields 23.

Outside the shields 23, a ring insert 25 extending concentrically with the axis of rotation is formed on the first housing part 2, on the inside of which a pair of annular copper bands 26, 27 are attached. The copper strips 26, 27 are electrically connected to the two terminals of the BNC terminal 8 in the terminal box 5 of the first housing part 2.

Between the ring insert 25 and the shields 23, a second concentrically extending annular insert 31 is formed on the second housing part 3, on the outside of a further pair of annular copper bands 28, 29 is arranged. The copper strips 28, 29 are electrically connected to the two terminals of the BNC terminal 8 in the terminal box 5 of the second housing part 3.

The ring inserts 25, 31 are arranged concentrically with each other and thus allow unrestricted rotational movement of the rotary connector.

The copper strips 26, 27, 28, 29 are radially aligned, that is, the normal of the surface points in the radial direction with respect to the axis of rotation. The copper strips 26 and 28 are arranged opposite one another at the same axial position and thus form a capacitive coupling element in the form of a capacitor. Likewise, the copper bands page 8

27 and 29 arranged on the same axial position opposite each other and thus form a second capacitive coupling element in the form of a capacitor.

Due to the two capacitive coupling elements operated in parallel, a transmission of RF signals from the BNC connection 8 of the first housing part 2 to the BNC connection 8 of the second housing part 3 is possible without contact, irrespective of the rotational position of the rotary transformer.

The ring width of the inserted copper strips 26, 27, 28, 29 is 2 cm, the copper strips 26, 27, 28, 29 of each capacitive coupling element are spaced 1 cm.

FIG. 3 shows a further embodiment of a rotary transformer according to the invention. Shown is a sectional view of a side of the rotary transformer. The axis of rotation 31 is indicated by a dashed line. The representation of the bearings and the electrical connections has been suppressed to improve the clarity of the drawing.

In a first housing part 2, an annular trough 33 made of ferromagnetic material is embedded. In this trough 33, the primary winding 32 is wound. In the space enclosed by the trough 33 engages an annular support 35 with the secondary winding 34 a. The primary winding 32 is thus arranged radially within the secondary winding 35.

The annular support 35 is fixed to the second housing part 3. In the second housing part 3, a lid 36 made of ferromagnetic material is incorporated, which closes the trough 33 in an annular manner. Thus, the interior of the trough 33 receiving the primary winding 32 and the secondary winding 34 is magnetically sealed against the outside.

First housing part 2 and second housing part 3 are rotatably mounted about the axis of rotation 31 against each other. Between the housing parts, a gap 37 is formed, which has an axially extending, rotationally symmetrical region 38 and terminates in a labyrinth seal 30.

In the side walls of the area 38, a first pair of copper strips 26, 27 are embedded and opposite the pair of copper strips 26, 27 a second pair of Page 9

Copper bands 28, 29. The copper bands 26, 27, 28, 29 are mounted on an electrically non-conductive substrate and electrically isolated from each other and against the environment.

A first copper strip 26 of the first pair thus forms, together with a first copper strip 28 of the second pair, a capacitor and thus a first capacitive coupling element. Likewise, the second copper strip 27 of the first pair together with the second copper strip 29 of the second pair forms a capacitor and thus a second capacitive coupling element. Thus, a transmission of signals via the capacitive coupling elements in each rotational position of the rotary transformer and independent of a rotational movement feasible.

Air is arranged between the two copper strips belonging to each capacitive coupling element.

First capacitive coupling element and second capacitive coupling element together form a transmission channel for data transmission.

In further developments, the copper strips 26, 27, 28, 29 of the rotary transformer are designed such that the smallest possible eddy currents are induced by the inductive coupling element.

FIG. 4a shows a first example of such a development. On a longitudinal strip 41 made of copper, transverse strips 42 made of copper are arranged to form a copper strip 40 and electrically connected thereto, so that gaps 43 are formed between the transverse strips 42. These gaps reduce induced eddy currents in the copper strip 40.

The copper strip 40 is assembled at the ends 44 to form an annular copper strip. In an alternative embodiment, the ends 44 are assembled to a gap, so that no circular currents can flow along the longitudinal strip 41.

FIG. 4b shows a second example of a development of the copper strips 26, 27, 28, 29. Page 10

In a copper strip 30 side incisions 45 are laterally introduced in the longitudinal direction, so that there is a total of a meandering extending conductor. The copper strip 40 is assembled at the ends 44 to form an annular copper strip. In an alternative embodiment, the ends 44 are assembled to a gap so that no circulating currents can flow along the copper strip 40.

In further embodiments, instead of copper, another metallic conductor, for example aluminum, is used.

Figure 5 shows the block diagram of a non-contact power and data transmission via a freely rotatable coupling.

A trained as a transducer head rotary transformer 61 comprises a primary side 56 and a secondary side 57 of a transformer, which are arranged rotatable against each other. The transformer forms the inductive coupling element for non-contact power transmission.

The primary side 56 is fed from a generator 54 with a constant alternating current with a current of 10 A or 60 A and a frequency of 25 kHz. Other frequencies between 10 kHz and 200 kHz are foreseeable.

This alternating current is passed through the transformer to a rectifier 55. To increase the coupling strength of the rectifier comprises a resonant circuit whose resonance frequency is tuned to the frequency of the injected alternating current.

The rectifier 55 supplies a load 60, for example a converter or a motor or an electronic circuit.

The generator 54 also provides a modem 50 and a transceiver 52. The modem 50 receives data via a line, not shown, and passes these as signals to the transceiver 52. The transceiver 52 amplifies the signals. Page 11

The rotary transformer 61 comprises a first capacitor 58 and a second capacitor 59. The capacitors 58, 59 form the capacitive coupling elements of a transmission channel for data transmission.

The capacitors 58, 59 are each designed so that the two plates are mutually movable.

Via the capacitors 58, 59 arranged in parallel, signals from the transceiver 53 can be transmitted to the transceiver 53 and vice versa. A return via a ground line is not necessary. Thus, the susceptibility is reduced.

The transceiver 53 is fed from the alternating current transmitted via the inductive coupling element, in particular from the rectifier 55. From the transceiver 53, the signals reach the modem 51, which is also supplied by the rectifier 55.

Conversely, the modem 51 may send data to the transceiver 53 received in the modem 50.

Thus, a bidirectional data exchange via a movable coupling device is provided, wherein parallel to the coupling for the data exchange, an inductive coupling is provided for energy from which a consumer and the transceivers 52, 53 and / or the modems 50, 51 are supplied.

Claims

Page 12Patent claims:

1. Coupling device with a first housing part and a second housing part, which are rotatably supported relative to each other about an axis, characterized in that form a primary winding and a secondary winding, an inductive coupling element, wherein the primary winding on the first housing part is arranged concentrically to the axis and the secondary winding is arranged on the second housing part concentric with the axis, on the first housing part an electrically conductive surface is formed as a first coupling surface and the second housing parts an electrically conductive surface is formed as a second coupling surface, which together form a capacitive coupling element.

Page 13

2. Coupling device according to claim 1, characterized in that

- On the first housing part electrically conductive surfaces, a first pair of

Coupling surfaces form and on the second housing parts electrically conductive surfaces a second pair of

Form coupling surfaces wherein each form an electrically conductive surface, in particular coupling surface, the first pair with an electrically conductive surface, in particular coupling surface, the second pair of capacitive coupling element.

3. Coupling device according to one of the preceding claims, characterized in that the housing parts are made of plastic or an electrically insulating material is provided between the housing parts and the respective electrically conductive surfaces.

4. Coupling device according to one of the preceding claims, characterized in that the inductive coupling element is surrounded by a magnetic shield.

5. Coupling device according to one of the preceding claims, characterized in that the magnetic shield between the inductive coupling element and capacitive coupling elements is arranged.

6. Coupling device according to one of the preceding claims, characterized in that the coupling surfaces are formed by metallic, annular bands whose surface is arranged in each case radially to the axis of rotation.

7. Coupling device according to one of the preceding claims, characterized in that the coupling surfaces of each pair are arranged on a common, imaginary cylinder. Page 14

8. Coupling device according to one of the preceding claims, characterized in that the turns of the primary winding and the secondary winding each extend about the axis of rotation 5.

9. Coupling device according to at least one of the preceding claims, characterized in that the primary winding and the secondary winding are each connected to a plug which has an extract safety 10.

10. Coupling device according to at least one of the preceding claims, characterized in that the inductive coupling element is arranged radially within the capacitive coupling elements. 15

11. Coupling device according to at least one of the preceding claims, characterized in that the capacitive coupling elements is arranged outside the magnetic shield of the inductive coupling element. 20

12. Coupling device according to at least one of the preceding claims, characterized in that each contact surface has a ring width of 1 cm to 3 cm, in particular 2 cm.

25 13. Coupling device according to at least one of the preceding claims, characterized in that the coupling surfaces of each capacitive coupling device 0.5 cm to 2 cm, in particular 1 cm, are spaced.

14. Coupling device according to at least one of the preceding claims, characterized in that the coupling surfaces of the capacitive coupling devices are each formed as an electrically conductive ring, which is electrically severed at one point. Page 15

15. Coupling device according to at least one of the preceding claims, characterized in that the coupling surfaces of the capacitive coupling devices are each connected in the middle between the ends formed by the transection with connection means.

16. Coupling device according to at least one of the preceding claims, characterized in that the coupling surfaces of the capacitive coupling devices in the circumferential direction have transverse gaps or cuts.

17. Coupling device according to at least one of the preceding claims, characterized in that the coupling surfaces are each mounted on an electrically insulating pad.