Magnet gear

Abstract

The magnetic gear includes a magnetic force generator (8), a driving shaft (1), a driven shaft (2) and a gear carrier (3) which are magnetically coupled in movement to one another. Only one magnetic force generator (8) is provided, which one magnetic force generator (8) has a north-south alignment that runs in the axis direction (111) of a shaft (1, 2) or parallel to this.

Claims

1. A magnetic gear comprising: only one magnetic force generator; a driving shaft; a driven shaft; a gear carrier, the driven shaft and the driving shaft being magnetically coupled in movement to one another, the only one magnetic force generator having a north-south alignment at least in sections that runs in an axis direction of at least one of the shafts or parallel to the axis direction of at least one of the shafts; a first magnetic conductor being axially and magnetically connected to the magnetic force generator; a second magnetic conductor being connected to the magnetic force generator; and an annular magnetic conductor, wherein: the driving shaft is connected to the magnetic force generator; the magnetic force generator or the first magnetic conductor comprises a first number of magnetically conducting radial projections; the driven shaft is connected to the annular magnetic conductor; the annular magnetic conductor surrounds the magnetic force generator or surrounds the second magnetic conductor; the annular magnetic conductor is magnetically connected to and mechanically separated from the magnetic force generator or the second magnetic conductor; the annular magnetic conductor comprises a second number of magnetically conducting radial projections; the gear carrier comprises a third number of elements which lead the magnetic flux between the radial projections and which are arranged annularly and peripherally of the radial projections.

2. A magnetic gear according to claim 1, wherein the magnetic force generator is formed by a disc or ring permanent magnet having a middle axis that coincides with an axis of one of the shafts.

3. A magnetic gear according to claim 2, wherein the magnetic force generator is segmented or is constructed of part-magnets of an equally directed polarity, said part-magnets being arranged next to one another.

4. A magnetic gear according to claim 3, wherein the magnetic force generator or the part-magnets are encapsulated into a rust-free steel encapsulation.

5. A magnetic gear according to claim 2, wherein the magnetic force generator or the part-magnets is/are laminated.

6. A magnetic gear according to claim 1, wherein the magnetic force generator is peripherally surrounded by an electrical coil which can be subjected to current from outside the gear.

7. A magnetic gear according to claim 1, wherein the magnetic force generator comprises an electromagnet or a superconductor.

8. A magnetic gear according to claim 1, wherein the driving shaft and driven shaft are aligned to one another and that the gear carrier is arranged axially to the alignment.

9. A magnetic gear according to claim 1, wherein the third number of elements leading the magnetic flux are formed by radially inwardly directed, magnetically effective projections of a ring of magnetically conductive material.

10. A magnetic gear according to claim 1, wherein at least one the third number of elements leading the magnetic flux is surrounded by an electric coil.

11. A magnetic gear according to claim 10, wherein the at least one electric coil is used for detecting a speed and/or a torque of the gear carrier, with regard to the driving shaft and/or the driven shaft.

12. A magnetic gear according to claim 1, wherein the gear carrier comprises two carrier discs which are distanced to one another and which are connected to one another by way of the third number of elements leading the magnetic flux.

13. A magnetic gear according to claim 12, wherein the driving shaft and the driven shaft are each rotatably mounted in a carrier disc.

14. A magnetic gear according to claim 1, further comprising electrically conductive separating elements of copper or aluminum are arranged between the radial projections and/or between the third number of elements leading the magnetic flux.

15. A magnetic gear according to claim 1, wherein disc magnetic conductors are arranged at both axial sides of the magnetic force generator.

16. A magnetic gear according to claim 1, wherein a distance of the third number of elements leading the magnetic flux corresponds to a width thereof, in the peripheral direction.

17. A magnetic gear according to claim 1, wherein means for the control of the magnetic flux are provided comprising a ring of soft-magnetic material which surrounds the third number of elements leading the magnetic flux and which is arranged in an axially displacably.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a longitudinal sectional view through a magnetic gear according to the invention, in a greatly simplified schematic representation;

(3) FIG. 2 is an exploded representation of the essential components of the gear according to FIG. 1;

(4) FIG. 3 is a schematic perspective representation showing the arrangement of the components which are magnetically engaged with one another, on transmitting the maximal torque;

(5) FIG. 4 is a schematic perspective representation of the arrangement according to FIG. 3, in the condition of the gear without force;

(6) FIG. 5 is a view showing five cross-sectional shapes of radial projections;

(7) FIG. 6 is a view showing five cross-sectional shapes of elements transmitting magnetic flux;

(8) FIG. 7 is a schematically sectioned representation of the arrangement of electrical conductors between magnetic conductors;

(9) FIG. 8 is a greatly schematically simplified representation showing a design variant of the magnetic gear;

(10) FIG. 9 is a greatly schematically simplified representation showing another design variant of the magnetic gear;

(11) FIG. 10 is a greatly schematically simplified representation showing another design variant of the magnetic gear;

(12) FIG. 11 is a greatly schematically simplified representation showing another design variant of the magnetic gear;

(13) FIG. 12 is a greatly schematically simplified representation showing another design variant of the magnetic gear;

(14) FIG. 13 is a greatly schematic simplified perspective representation of the construction of a laminated magnet;

(15) FIG. 14 is a lateral view of the magnetic according to FIG. 13;

(16) FIG. 15 is a greatly simplified perspective representation of the construction of a magnet formed from segments;

(17) FIG. 16 is a plan view of the magnet according to FIG. 15; and

(18) FIG. 17 is a schematic perspective representation showing an embodiment variant of the magnetic gear according to FIG. 1, with a soft-magnetic, axially displaceable ring.

DESCRIPTION OF PREFERRED EMBODIMENTS

(19) Referring to the drawings, the represented magnetic gear is a reluctance gear and comprises a driving shaft 1, a driven shaft 2 and a gear carrier 3 which are magnetically coupled to one another and rotate in a fixed ratio to one another. If the gear is to serve as a step-up gear, then the drive is effected by way of the driving shaft 1 which is coupled for example to a drive motor, wherein the drive output is selectively effected via the driven shaft 2 or the gear carrier 3 which is then accordingly designed for example as a hollow shaft, surrounding the driven shaft 2. A step-up from an input rotation speed of the driving shaft 1 to a higher output rotation speed of the driven shaft 2 or of the gear carrier 3 or the shaft connected thereto is effected with this arrangement, as will be explained in more detail further below. If the drive is effected via the shaft 2 or the gear carrier 3, thus if an electric motor is coupled to this side of the gear, then the gear functions as a step-down gear and the shaft 1 then forms the driven shaft.

(20) The driving shaft 1 at its end which in the inside of the gear comprises a flange 4, on which a disc (a first magnetic conductor disc) 5 of magnetically conductive material bears, said disc comprising a number Z1 of radial projections 6 which project radially outwards beyond the cylindrical main body, similarly to the teeth of a gearwheel or cog. In the embodiment example, the disc 5 comprises seventeen teeth Z1 which, as is particularly evident from FIG. 2, project radially beyond the cylindrical main body of the disc 5 and whose width in the peripheral direction corresponds roughly to their peripheral distance to one another. This disc 5 in a manner aligned to threaded bores in the flange 4 comprises bores, through which the screws 7 are led, wherein the heads of these screws lie sunk within the disc 5, and with which screws the disc 5 is fastened on the flange 4 of the driving shaft 1.

(21) The disc 5 comprises a central through-bore which is arranged aligned to a central threaded bore at the flange-side end of the driving shaft 1. A disc-like cylindrical magnet (a magnetic force generator) 8 connects to the disc 5 with the same axis, at the side which is away from the flange 4, and as well connecting to this magnet, a magnetically conductive, disc-like cylindrical body (second magnetic conductor) 9. The body 9, the magnet 8 and the disc 5 each comprise a central bore, and these bores are arranged aligned to one another. A screw 10 which passes through the bore and whose shank passes through the body 9, the magnet 8 and the disc 5, and which is fixed in the central threaded bore of the driving shaft 1, is seated in the body 9 in a sunken manner. This screw 10 thus fastens the disc 5, the magnet 8 and the body 9 on the flange 4 of the driving shaft 1 and fixedly connects these components to one another.

(22) The magnet 8 in the represented FIG. 1 and which inasmuch as this is concerned is true to scale, has an axial length which corresponds roughly to a third of the axial length of the body 9 or the disc 5. Thereby, the longitudinal axis 111 of the body 9, of the magnet 8 and of the disc 5 coincides with the longitudinal and rotation axis 111 of the driving shaft 1, the driven shaft 2 and the gear carrier 3. The diameter of the magnet 8 and that of the body 9 are equally large, and smaller than the core diameter of the disc 5 at the foot of the radial projections (Z1) 6.

(23) A bearing 11, in which the end of the driven shaft 2 which faces the inside of the gear is mounted in a rotatable manner with respect to the drive-side components, is sunk in the disc-like body 9 at the side which faces the driven shaft 2.

(24) The driven shaft 2 likewise comprises a flange 12 which however is not arranged at the end, but at a distance to the end of the shaft 2 which is in the gear. A carrier 13 is connected via this flange 12 and via screws to the driven shaft 2 and is arranged at a slight distance to, but separated from the body 9, but however projects radially beyond this at diametrically opposite sides. The carrier 13 is connected in this projecting region 14 to an annular body (annular magnetic conductor) 15 surrounding the body 9 with slight play.

(25) This annular body 15 comprises radial projections (Z2) 16 and the number Z2 of these radial projections 16 is two with the embodiment example. The annular body 15 in the region of its radial projections 16 is fixedly connected to the projecting region 14 of the carrier 13 by way of screws arranged parallel to the axis 111. The radial projections 16 extend over an angular region of 90, so that the peripheral free spaces which are formed therebetween also extent over 90 of the periphery, as can also be particularly deduced from the FIGS. 2-4. At least the annular body 15 with its radial projections 16, but also the carrier 13 are likewise formed from magnetically conductive material.

(26) The driving shaft 1 and the driven shaft 2 are mounted in a disc-like body 19 of the gear carrier 3, in each case via two bearings 17, 18, wherein the inner-lying bearings 17 are arranged within the disc-like body 19, whereas the outer bearings 18 are each arranged in a ring 20 which is screw-connected to the disc-like body 19.

(27) The gear carrier 3 is arranged in a freely rotatable manner with respect to the shafts 1 and 2, via the bearings 17, 18. Elements (Z3) 21 which lead the magnetic flux between the radial projections 6 and the radial projections 16 and which are also indicated as pole rods or in their entirely as modulators, are provided between the disc-like bodies 19 of the gear carrier 3. These elements 21 in the represented embodiment are cuboid and extend so far in the longitudinal direction that they radially connect with a small distance onto the projects 6 as well as the projections 16. These elements 21 are arranged distributed on an imaginary ring at the same distance to one another, and have a width which corresponds to their distance to one another, specifically measured where they reach closest up to the projections 6 and 16, opposite which projections they are distanced with little play. The elements 21 in the embodiment represented by way of FIGS. 1-4 are connected to a disc-like body 19 in each case by way of two screws, so that a cage-like structure of the gear carrier 3 results.

(28) The movement principle of the reluctance gear which is described above is based in the fact that the gear parts moveable to one another move such that a magnetic circuit, in which a magnetic flux is built up by the permanent magnets 8, is aligned or directed such that its magnetic resistance is minimal. The magnetic flux departing from the magnet 8 to the driving shaft 1 is transmitted onto the magnetically conductive disc 5 and there undergoes a deflection by 90 in the direction of one or more of the radial projections 6. This magnetic flux is then transmitted from the radial projections 6 onto one or more of the elements 21 depending on the position of the gear carrier 3, and from there in turn onto one or more of the radial projections 16. The magnetic flux gets from the radial projections 16 to the cylindrical disc body 9 and from there back to the magnet 8, by which means the magnetic circuit is closed.

(29) The sum of the torques between the driving shaft 1, driven shaft 2 and gear carrier 3 is always zero. The speed transfer ratio (gear ratio) of the gear results from the ratio of the radial projections 6 (Z1number of the radial projections 6), of the radial projections 16 (Z2number of radial projections 16) and the elements 21 (Z3number of the elements 21) and specifically as follows:

(30) The speed transfer ratio between the drive input and drive output corresponds to the ratio Z2 to Z1, wherein Z3 is equal to Z1 plus Z2. A speed transfer ratio of 1 to 7.5 results from this in the presently described embodiment example, which is to say that if the driving shaft 1 rotates once, the driven shaft rotates 7.5 times, assuming that the gear carrier 3 is fixed and does not co-rotate. Thereby, the driving shaft 1 and the driven shaft 2 rotate in opposite directions.

(31) As specified initially, the gear can also be applied in the reverse direction, thus the drive input is effected via the shaft 2 and the drive output via the shaft 1 or via the gear carrier 3, similarly to that which is possible with a three-shaft planetary gear. Thereby, the following relations basically result:

(32) The speed transfer ratio in the case of a non-rotating, thus fixed gear carrier 3 is thus as follows:

(33) $\begin{array}{cc}{R}_{\mathrm{gearcarrrierfixed}}=\frac{L}{H}=-D.Math.\frac{Z2}{Z1}& \left(1\right)\end{array}$
wherein R.sub.gearcarrierfixed is the speed transfer ratio L the speed of the driving shaft 1 H the speed of the driven shaft 2 D the rotation direction 1 if the driving shaft and driven shaft rotate in opposite directions, 1 if the driving shaft and driven shaft rotate in the same direction Z1 number of radial projections 6 Z2 number of radial projections 16 Z3 number of elements 21.
Z3=Z1+D.Math.Z2(2)

(34) If the gear carrier 3 co-rotates, basically the follow relation must be fulfilled:

(35) $\begin{array}{cc}\frac{L-O}{H-O}=-D.Math.\frac{Z2}{Z1}& \left(3\right)\end{array}$
wherein
is the speed of the gear carrier.

(36) If the driven shaft 2 is fixed instead of the gear carrier, then the following speed transfer ratio results:

(37) $\begin{array}{cc}{R}_{\mathrm{drivenshaftfixed}}=\frac{O}{H}=\frac{D.Math.Z2}{Z1+D.Math.Z2}& \left(4\right)\end{array}$

(38) The meaning and purpose of the drive is to increase or to reduce the speed of the driven side with respect to the drive side, which is to say to reduce or increase the moment to be transmitted. The following relation results with regard to the powers:
P.sub.h+P.sub.l+P.sub.s=P.sub.m(5)
wherein
P.sub.h is the power of the driven shaft
P.sub.l the power at the driving shaft, and
P.sub.s the power at the gear carrier.
The resulting power P.sub.m is the power stored in the gear.

(39) If one sets the power stored in the gear P.sub.m=0, then the following equation comprising the torques results:
T.sub.h.Math.H+T.sub.l.Math.L+T.sub.s.Math.O=0(6)
wherein
T.sub.h is the torque at the driven shaft 2 and
T.sub.l the torque at the driving shaft 1 and
T.sub.s the torque at the gear carrier.
The following relation results if the gear carrier is fixed:

(40) $\begin{array}{cc}-T_h.Math.\frac{H}{L}=T_l& \left(7\right)\end{array}$
and the following relation if the driven shaft 2 is fixed:

(41) $\begin{array}{cc}-T_h.Math.\frac{H}{O}=T_s& \left(8\right)\end{array}$

(42) As FIGS. 3 and 4 indicate, the angle B between a radial projection 16 and an element 21 is relatively small in the force-free condition, which is to say when no external forces act upon the gear, as is represented in FIG. 4. The magnetic gear in this force-free condition can be operated in both directions. This angle B however significantly increases, as is represented by way of FIG. 3, when the magnet gear transmits the maximal possible torque. The gear is then fixed in the direction of rotation.

(43) Different cross-sectional shapes of the radial projections 6 and 16, as can be applied in order to influence the torque course, are represented by way of FIG. 5. The so-called cogging effect, which is to say the pulsation of the gear can thus be largely reduced by way of rounding the projections, as is represented to the greatest extent in the far right representation of FIG. 5, but this can be to such an extent that the gear can then only be applied in one direction, for example as a step-up gear if the radial projections 16 have such a rounded shape, and not in the reverse direction. Corresponding designs can have the elements 21, and the cross-sectional shapes in the regions which lie opposite the radial projections 6, 16 are represented by way of example by way of FIG. 6. The radial projections 6, 16 and/or the elements 21 can be arranged in an obliquely set manner, similarly to that which is known in the state of the art when staggering rotors of electric motors, so as to reduce this cogging effect.

(44) The magnetic flux within the gear can be bundled by way of electrical conductors being arranged either between the radial projections 6, 16 and/or between the elements 21. Electrical conductors 22 are arranged between the radial projections 6, and electrical conductors 23 between the elements 21, in FIG. 7, and these conductors consist of aluminum and prevent a magnetic flux from arising in this region, by which means the magnetic flux is bundled in the remaining regions and the transmittable torque is increased.

(45) As to how the magnetic force of the magnet 8 can be varied and/or increased by way of an electric coil 24 being arranged in a manner surrounding this magnet and being suitably subjected to current, is schematically represented by way of FIG. 8. The current-subjection is created by a current generator which is not represented. If the current generator fails, the gear still continues to function, but a variation of the magnetic force is no longer possible.

(46) FIG. 9 shows one embodiment variant, with which the magnet 8, the coil 24 and the elements 21, which is to say the gear carrier 3 are stationarily arranged, whereas the drive input and drive output are each arranged in a manner rotatable with these radial projections 6 and 16.

(47) One embodiment variant corresponding to FIG. 9 is represented by way of FIG. 10, with which the permanent magnet 8 has been done away with and the magnetic force is produced exclusively by the electrical coil 24 with the electrically conductive material which is arranged therein.

(48) It is represented in FIG. 11 as to how a bundling of the magnetic field which is produced by the permanent magnet 8 can be achieved by way of an electrically conductive ring 25 which is formed from copper, being arranged surrounding the magnet 8. The magnetic flux within the gear and with this, the torque which can be transmitted, can also be increased by way of this.

(49) It is schematically represented by way of FIG. 12, as to how a part of the gear, specifically the drive shaft 1 and the disc 5 are separated from the remaining part of the gear by way of an encapsulation 26. This encapsulation 26 consisting of stainless steel and in the form of a separating wall 26 permits a part of the gear to be let running in another medium, as is necessary for example for the processing of chemical substances with stirrers or likewise.

(50) The permanent magnet 8 does not necessarily need to be a homogeneous cylindrical magnet body, as is represented by way of FIGS. 1 and 2, but it can thereby also be the case of a laminated magnet (magnetic force generator) 8a, as is represented by way of example by way of FIGS. 13 and 14, which is formed there from three individual magnet discs, as is counted as belonging to the state of the art.

(51) An alternative design is a segmented magnet (magnetic force generator) 8b, as is represented by way of FIGS. 15 and 16. The magnet consist of six equally large segments 28 which, put together, result in a magnet 8b, which is polarized in a direction of its longitudinal middle axis 111 just as the case with the laminated magnet 8a.

(52) It is represented by way of FIG. 17, as to how the transmittable torque can be influenced with the help of a soft-magnetic ring 29 which surrounds the elements 28 at a small distance. The ring 29 is displaceable within the gear in the direction of the axis 111, so that it can completely or partly (as is represented in FIG. 17) surround the elements 21, or not at all. The displacement directions are symbolized in FIG. 17 by the double arrow 30. This ring 29 is formed from soft-magnetic material and surround the elements 21 in the manner of a jacket, but does not contact them. The ring 29 is utilized for the control of the magnetic flux from the magnetic force generator 8. If the ring 29 covers the elements only by half as is represented in FIG. 17, then the magnetic flux is only slightly weakened. If the ring 29 is pushed over completely, so that it peripherally covers the elements 21, then the magnetic flux is greatly weakened. This arrangement is advantageous in the cases when the starting of the gear is problematic due to the cogging torque. The cogging torque is reduced when the ring 29 peripherally surrounds the elements 21, so that the start-up of the gear is simplified. This ring 29 can be retracted gain after the gear is in motion, so that the magnetic flux is then maximal and the torque which can be transmitted by the gear is maximal.