DEVICE FOR TRANSMITTING ROTATIONAL MOTIONS WITHOUT CONTACT

Abstract

A device for transmitting rotational motions without contact may include an inner rotor with at least one inner-rotor magnet and an outer rotor with at least one outer-rotor magnet. The inner rotor and the outer rotor are magnetically coupled to one another and rotatable along a rotation direction about a common axis of rotation. The at least one inner-rotor magnet and/or the at least one outer-rotor magnet may have a magnetization that is at least one of diametric, radial, and lateral. The at least one inner-rotor magnet may have a different type of magnetization than the at least one outer-rotor magnet.

Claims

1. A device for transmitting rotational motions without contact, comprising: an inner rotor including at least one inner-rotor magnet; an outer rotor including at least one outer-rotor magnet and magnetically coupled to the inner rotor, the inner rotor and the outer rotor rotatable along a direction of rotation about a common axis of rotation, the at least one inner-rotor magnet having at least one of a diametric magnetization, a radial magnetization, and a lateral magnetization; the at least one inner-rotor magnet and the at least one outer-rotor magnet having different types of magnetization from one another; wherein at least one of the at least one inner-rotor magnet includes at least two inner-rotor magnets arranged along the direction of rotation on the inner rotor and the at least one outer-rotor magnet includes at least two outer-rotor magnets arranged along the direction of rotation on the outer rotor; wherein the at least one of the at least two inner-rotor magnets and the at least two outer-rotor magnets have a respective direction of magnetization that differ from one another; and wherein the at least two inner-rotor magnets each have a diametric magnetization, and the at least two outer-rotor magnets each have a lateral magnetization.

2. The device according to claim 1, wherein at least one of the at least one inner-rotor magnet and the at least one outer-rotor magnet is configured as a ring magnet.

3. The device according to claim 1, further comprising at least two pole pins arranged between the inner rotor and the outer rotor along the direction of rotation.

4. The device according to claim 1, further comprising: a drive shaft connected in a torque-proof manner to one of the inner rotor and the outer rotor and an output shaft connected in a torque-proof manner to the other of the inner rotor, and the outer rotor; a sealing body configured as a pot including a pot base and a pot collar, the pot collar arranged radially between the inner rotor and the outer rotor; and wherein the pot collar of the sealing body extends axially away from the pot base into a radially outwardly projecting flange section for coupling to a flow machine configured to be drive-connected to the output shaft.

5. The device according to claim 4, wherein the drive shaft is drive-connected to a transmission unit for reducing the rotational speed of the drive shaft.

6. A drive system, comprising: a device for transmitting rotational motions without contact, the device including: an inner rotor including at least one inner-rotor magnet having at least one of a diametric magnetization, a radial magnetization, and a lateral magnetization; an outer rotor including at least one outer-rotor magnet and magnetically coupled to the inner rotor, the at least one outer-rotor magnet having a different type of magnetization then the at least one inner-rotor magnet the inner rotor and the outer rotor rotatable along a direction of rotation about a common axis of rotation; a drive shaft connected in a torque-proof manner to one of the inner rotor and the outer rotor; an output shaft connected in a torque-proof manner to the other of the inner rotor and the outer rotor; a sealing body having a pot shape including a pot base and a pot collar, the pot collar arranged radially between the inner rotor and the outer rotor, and the pot collar extending axially away from the pot base into a radially outwardly projecting flange section; wherein at least one of the at least one inner-rotor magnet includes at least two inner-rotor magnets arranged circumferentially along the direction of rotation on the inner rotor and the at least one outer-rotor magnet includes at least two outer-rotor magnets arranged circumferentially along the direction of rotation on the outer rotor; wherein the at least one of the at least two inner-rotor magnets and the at least two outer-rotor magnets have a respective direction of magnetization that differs from one another; and wherein the at least two inner-rotor magnets each have a diametric magnetization, and the at least two outer-rotor magnets each have a lateral magnetization; a flow machine drive-connected to the output shaft of the device; and wherein the sealing body is coupled to a housing of the flow machine the flange section.

7. The drive system according to claim 6, further comprising a transmission unit, wherein the drive shaft is drive-connected to the transmission unit for reducing the rotational of the drive shaft.

8. The drive system according to claim 6, wherein at least one of the at least one inner-rotor magnet and the at least one outer-rotor magnet is structured as a ring magnet.

9. The drive system according to claim 6, wherein the inner rotor is coupled to the output shaft.

10. The drive system according to claim 6, wherein the device further includes at least two pole pins arranged between the inner rotor and the outer rotor along the direction of rotation.

11. The drive system according to claim 6, wherein the at least one inner-rotor magnet includes a plurality of diametrically magnetized magnets with alternating polarity provided on the inner rotor along the direction of rotation.

12. The drive system according to claim 6, wherein the at least one outer-rotor magnet includes a plurality of laterally magnetized magnets with alternating polarity provided on the outer rotor along the direction of rotation.

13. The device according to claim 1, wherein the at least two inner-rotor magnets with the diametric magnetization have a magnetic field line extending parallel to one another in a plane perpendicular to the common axis of rotation.

14. The device according to claim 1, wherein the at least two outer-rotor magnets with the lateral magnetization have alternating polarity with a magnetic field line extending circumferentially to the common axis of rotation.

15. The device according to claim 1, wherein the at least one inner-rotor magnet is structured as a ring magnet.

16. The device according to claim 1, wherein the at least one outer-rotor magnet is structured as a ring magnet.

17. The device according to claim 1, wherein the at least one inner-rotor magnet further includes a plurality of inner-rotor magnets having the diametric magnetization arranged circumferentially on the inner rotor with alternating magnetic poles along the direction of rotation.

18. The device according to claim 16, wherein the respective directions of magnetization of the plurality of inner-rotor magnets define an angle a according to the following relationship: α=(180°/number of pole pairs)±180°.

19. The device according to claim 16, wherein the at least one outer-rotor magnet further includes a plurality of outer-rotor magnets having the lateral magnetization arranged circumferentially on the outer rotor with alternating magnetic poles along the direction of rotation.

20. The device according to claim 18, further comprising a plurality of pole pins arranged between the inner rotor and the outer rotor along the direction of rotation, wherein a number of the plurality of pole pins corresponds to the following relationship: the number of the plurality of pole pins=(number of outer rotor pole pairs+number of inner rotor pole pairs)/2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the figures, in each case schematically:

[0029] FIG. 1 shows an example of a device according to the invention for transmission of rotational motions without contact in a longitudinal section,

[0030] FIGS. 2A to 2C show examples for various types of magnetization illustrated by means of a ring magnet,

[0031] FIGS. 3A to 3C show various examples for devices according to the invention for transmission of rotational motions without contact with outer and inner rotor having different types of magnetization.

DETAILED DESCRIPTION

[0032] FIG. 1 illustrate roughly schematically and in a longitudinal section a device according to the invention, here configured as magnetic coupling 1, for transmission of rotational motions without contact. This comprises an inner rotor 2 having an inner-rotor magnet 3 and an outer rotor 4 which comprises at least one magnetic outer-rotor magnet 5 and which is magnetically coupled to the inner rotor 2. Inner rotor 2 and outer rotor 4 are rotationally adjustable about a common axis of rotation R.

[0033] The magnetic coupling 1 shown as an example in the example scenario may serve to transmit a torque produced by a flow machine (not shown), for example of a gas turbine or a fluid pump in an output shaft 6 to a drive shaft 7 for further use. For this purpose the output shaft 6 can be connected in a torque-proof manner to the inner rotor 2 and the drive shaft 7 can be connected in a torque-proof manner to the outer rotor 4 or conversely.

[0034] This approach allows the flow machine to be configured as a component separate from the actual magnetic coupling 1, possibly if the flow machine is a gas turbine with blade wheels arranged in a torque-proof manner on the output shaft 6 so that said output shaft has fluid flowing around it due to the design.

[0035] In order to be able to seal the flow machine including the output shaft 6 fluidically towards the further components of the magnetic coupling 1, this comprises a sealing body 8 configured in the manner of a pot with a pot base 9 and a pot collar 10, wherein the pot collar 10 is arranged as shown in FIG. 1 in relation to a radial direction r of the magnetic coupling 1 in a gap 11 between outer rotor 4 and inner rotor 2. It can be deduced from the example scenario of FIG. 1 that the pot collar 10 goes over axially at the end into a radially outwardly protruding flange section 21 which can be fastened directly to a housing of the flow machine (not shown). Consequently a fluid can certainly flow around the region 12 around the output shaft 6 including the inner rotor 2 but the sealing body 8 seals this region outwards, i.e. towards the outer rotor 4.

[0036] Since the rotational speeds produced by flow machines in the output shaft 6 are frequently very high, it can be necessary to reduce these in order to be used by the devices downstream of the flow machine. A suitable measure in this case for reducing the rotational speed of the output shaft 6 to a suitable value is the use of a transmission unit 13 indicated only roughly schematically in FIG. 1 which has an input shaft 13 connected in a torque-proof manner to the drive shaft 7. Such a transmission unit 13 can have a multistage structure if high transmission ratios, possibly of 10:1 or higher are to be achieved. The reduced rotational speed compared with the input shaft 14 is provided at an output shaft 15. The transmission unit 13 together with the magnetic coupling 1 thus forms a magnetic transmission 16.

[0037] The respective magnetization of the inner-rotor and/or outer-rotor magnets 3, 5 arranged on the inner and outer rotor 2, 4 is crucial for the effective magnetic coupling of the outer rotor 4 to the inner rotor 2 and thus for effective transmission of torque from the inner rotor 2 to the outer rotor 4. In principle, three types of magnetization come into consideration for this in each case and specifically a radial, diametric or lateral magnetization. The profile of the magnetic field lines accompanying the respective type of magnetization is shown in the examples of FIGS. 2a to 2c. The ring magnet 17a shown in FIG. 2a with alternating magnetic poles S, N both in the circumferential direction U and in the radial direction—a magnetic south pole is designated by the letter “S” and a magnetic north pole is accordingly designated by “N”—generates a magnetic field with field lines extending alternately radially inwards or radially outwards in the circumferential direction U.

[0038] FIG. 2b shows in contrast a ring magnet 17b with diametric magnetization. The ring magnet 17b has for this purpose only one magnetic north pole and one magnetic south pole. In contrast to the magnetic field lines of the ring magnet 17a, those of the ring magnet 17b extend parallel to one another in a plane perpendicular to the axis of symmetry S′ of the ring magnet 17b.

[0039] FIG. 2c finally shows a ring magnet 17c with magnetic north and south poles alternating along the direction of rotation D. Such an arrangement of the magnetic poles results in a so-called lateral magnetization which is known to the person skilled in the art under the term “Halbach magnetization”.

[0040] Various examples of the magnetic coupling 1 according to the invention whose inner-rotor or outer-rotor magnets 2, 3 differ from one another in their respective type of magnetization will now be explained with reference to FIGS. 3a to 3c.

[0041] The example in FIG. 3a shows in a cross-section a magnetic coupling 1 having an outer rotor 4 on which four outer-rotor magnets 5 are fastened radially inwards, these being arranged along the direction of rotation D in such a manner that for the outer rotor 4 the radial magnetization shown in FIG. 2a is obtained with field lines 18a of the magnetic field running according in or contrary to the radial direction. Accordingly, four inner-rotor magnets 3 with likewise alternating polarity are provided on the inner rotor 2 along the direction of rotation and specifically in such a manner that a magnetic field having a field line profile corresponding to that of a lateral magnetization is obtained for the inner rotor 2. A ground ring 19 can be provided radially outwards on the outer rotor 4 by means of which the circuit (cf. dashed field lines in FIG. 3a) of the magnetic field lines 18a required with a magnetic dipole field can be produced. The arrangement with radial magnetization of the outer rotor 4 and lateral magnetization of the inner rotor 2 shown in FIG. 3a is characterized by a particularly good magnetic coupling of inner and outer rotor 2, 4 as a result of the resulting overall field line profile. The use of a radial magnetization on the outer rotor 4 additionally allows the constructively advantageous use of mechanically particularly stable ring magnets.

[0042] The same applies for the example of FIG. 3b which shows an outer rotor 4 with six outer-rotor magnets 5 with alternating magnetic polarity (N, S) arranged radially inwards along the direction of rotation D and adjacent to one another so that a lateral magnetization is obtained as a result. The field line profile accompanying such a lateral magnetization provides for an automatic circuit of the magnetic field lines on the outer rotor 4 which, compared with the example of FIG. 3a, makes the provision of a ground ring radially outwards on the outer motor 4 no longer necessary. The inner rotor 2 in the example of FIG. 3b is provided with a diametric magnetization. Four inner-rotor magnets 3 are attached to the inner rotor 2 in the direction of rotation D which each have in sections the typical parallel field line profile for a diametric magnetization. Two adjacent inner-rotor magnets 3 along the direction of rotation D have directions of magnetization which are arranged at a 90° angle with respect to one another. In addition, five pole pins 20 are arranged between inner and outer rotor 2, 4 along the direction of rotation D which serve to harmonize the field line profile between outer and inner rotor 4, 2. The pole pins 20 can be made of steel or sheet metal; according to one variant not shown in FIG. 2b, these can also be fastened directly to the outer rotor 4.

[0043] FIG. 3c finally illustrates a magnetic coupling 1 with a radial magnetization of the outer rotor 4 already explained with reference to the example of FIG. 3a whereas the inner rotor 2 has the diametric magnetization already described in connection with FIG. 3b.