Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/27—Rotor cores with permanent magnets
  • H02K1/2706—Inner rotors
  • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
  • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
  • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
  • H02K1/278—Surface mounted magnets; Inset magnets

Definitions

• the invention relates to a rotor for an electrical machine, in particular for an electric motor, with the features of the preamble of claim 1
• rotors for, for example, brushless DC motors (BLDC motors) with a back yoke, on the circumference of which permanent magnets are arranged.
• the inference can be composed of laminations as a laminated core.
• BLDC motors brushless DC motors
• yoke with the permanent magnets in a protective tube.
• the permanent magnets have to be positioned at the back yoke and must be held during the curing of the adhesive, synthetic resin or plastic or during the insertion into the protective tube.
• holders must be provided in an injection mold, which hold the permanent magnets positioned on the back yoke during the injection process. When shedding the tolerant permanent magnets are inserted in tolerances recesses of the yoke and consequently cast in undefined positions.
• the problem with positioning the permanent magnets at the back yoke is the manufacturing tolerance of the permanent magnets. Since the manufacturing tolerances do not decrease to the same extent as the dimensions themselves when the dimensions become smaller, relative inaccuracies increase with decreasing size of the permanent magnets and the rotors. Relative inaccuracy means a tolerance with regard to absolute component dimensions. In particular when using rare earth magnets, which have a magnetic force that is several times higher than conventional ferrite magnets and which can therefore be smaller, an inaccuracy of the positioning becomes noticeable due to the small absolute dimensions of the magnets and the rotor.
• the invention is therefore intended in particular for small permanent magnets, for example the rare earth magnets mentioned, and for small rotors and small motors. However, the invention can in principle be used for all sizes of electrical machines and rotors as well as all magnet types.
• the rotor according to the invention with the features of claim 1 has a back yoke with a laminated core consisting of fins and a number of permanent magnets arranged at the back yoke.
• Lamellae of the laminated core of the yoke of the rotor have at least one fixing element which is integral with the lamellae.
• the permanent magnets are fixed between two fixing elements, which are fixed relative to each other Permanent magnets are preferably arranged opposite one another.
• Each lamella preferably has one or more pairs of fixing elements, a permanent magnet being fixed between a pair of fixing elements.
• a permanent magnet can also be fixed between two fixing elements of different lamellae, so that lamellae with a fixing element or individual fixing elements are possible instead of one or more pairs of fixing elements.
• the rotor according to the invention can also have fins without fixing elements. With their fixing elements, in particular a lamella clamps one, several, and possibly also all permanent magnets of the rotor, depending on whether it has one or more pairs of fixing elements. Fixing elements of several lamellae are provided for fixing a permanent magnet.
• the fixing elements have the advantage that they compensate for the manufacturing tolerances of the permanent magnets. Since the fixing elements fix a permanent magnet on sides of the permanent magnet facing away from one another, in particular clamp them, they position the permanent magnet between them irrespective of its manufacturing tolerance.
• the fixing elements keep the permanent magnets of the rotor in position during gluing, casting or spraying until an adhesive, plastic or synthetic resin has hardened.
• the fixing elements also hold the permanent magnets in position when the rotor is inserted into a protective tube.
• An additional advantage of the fixing elements is that they contribute to torque transmission and offer protection against displacement in the event of a mechanical defect in the electrical machine.
• the back yoke has mutually rotated lamellae, between the spring elements of which different permanent magnets are clamped.
• the slats are rotated by 360 ° divided by the number of permanent magnets or a multiple thereof.
• pairs of spring eggs may be provided on a lamella for every second permanent magnet. This is advantageous or necessary if the provision of spring element pairs on one lamella is difficult or not possible for all permanent magnets for reasons of space.
• twisting the slats against each other has the advantage that fluctuating slat thicknesses and warped slats are compensated for over a surface of the slats, in particular if such shape errors are systematic, ie are present in all slats.
• the lamellae c 15 can have sides of different thicknesses, for example by rolling the sheet, these shape errors being the same for each lamella.
• the rotor according to the invention is particularly useful as so-called internal rotor.
• With on an outer periphery of the laminated core of the 'inference 2.0 arranged permanent magnet is provided (claim 5).
• the rotor With on an outer periphery of the laminated core of the 'inference 2.0 arranged permanent magnet is provided (claim 5).
• the rotor it is also possible to design the rotor as a so-called external rotor with permanent magnets arranged on an inner circumference of the laminated core.
• lamellae of the laminated core must be ring-shaped, ie have a hole.
• the fixing elements are spring elements (claim 6) which clamp the permanent magnets between them due to their elasticity. This achieves a compensation of permanent magnets of different widths.
• Figure 2 shows a conclusion of the rotor according to the invention with laminated cores composed of lamellae according to Figure 1 in perspective
• FIG. 3 shows the inference from FIG. 2 with permanent magnets.
• the lamella 10 shown in Figure 1 is stamped from a sheet metal. It has an essentially square shape with a central hole 12. At each corner, the lamella 10 has a spring element 14 which is designed as a Fecler tongue which is one-piece with the lamella 10 and which is produced in one operation by punching the lamella 10. Instead of being punched, the lamella 10 with the spring elements 14 can also be produced by laser cutting, water jet cutting, eroding or another method. In each case two adjacent spring elements 14 face each other and are assigned to one another, they form a pair of spring elements 14. In FIG. 1, the two spring elements 14 shown above and the two below are assigned to one another and form a pair.
• lamellae 10 are assembled to form a laminated core 18. All lamellae 10 of the laminated core 18 are identical and have the shape shown in FIG. 1. In each case, a number of, for example, five to six slats 10 is congruently assembled. The next, for example, five to six slats 10 are rotated by 90 °. The angle of rotation of 90 ° applies to the illustrated and described embodiment of the invention, in which the rotor has four permanent magnets. In general, the angle of rotation of the lamellae 10 is 360 ° divided by the number of permanent magnets.
• the yoke 16 By twisting the slats 10 against one another, the yoke 16 has spring element pairs 14 arranged on all of its four outer or circumferential sides 20 distributed over its axial length, although the individual lamellae 10 have spring element pairs 14 only on two of four outer sides.
• the next but one, for example five to six slats 10 are rotated by a further 90 °, that is to say rotated by 180 ° with respect to the first slats 10.
• manufacturing-related, systematic thickness and shape errors of the slats 10 are compensated for.
• systematic it is meant that the inaccuracy is present at the same point on each lamella 10.
• Such manufacturing inaccuracy can be, for example, a local difference in thickness or a local curvature of the lamella 10, which is present at the same location on each lamella 10.
• the rotor 16 has four permanent magnets 22 (FIG. 3).
• the permanent magnets 22 have a D-shaped cross section (“loaf of bread”), that is to say they have a flat base side with which they rest on the outside 20 of the rotor 16.
• Longitudinal side surfaces 24 of the permanent magnets 22 that are axially parallel to the rotor are perpendicular to the base surface and are low in relation to a width of the base area, an outer surface 26 of the permanent magnets 22 facing away from the yoke 16 is curved in a cylindrical shape, a cylinder radius corresponding to a distance of the outer surface 26 from an imaginary rotor axis.
• the number and shape of the permanent magnets 22 can differ from the above information in other configurations of the invention.
• the permanent magnets 22 can be, for example, cylindrical shells instead of D-shaped (not shown), in this case the lamellae 10 preferably have a circular instead of a square basic shape, and the permanent magnets are convex with a concave inner surface curved peripheral edge of the slats. It is also not imperative that the cylinder radius of the outer surface 26 of the permanent magnets 22 coincides with a distance from the imaginary rotor axis.
• the permanent magnets 22 are inserted between the spring element pairs 14, the spring elements 14 resiliently pressing against the longitudinal side surfaces 24 of the permanent magnets 22 and in this way clamping the permanent magnets 22 between them and thus at the yoke 16. Since the spring elements 14 press uniformly against the permanent magnets 22 from both sides, the spring elements 14 position the permanent magnets 22 in the lateral (tangential or circumferential) direction and the same manufacturing tolerances of the permanent magnets 22.
• the spring elements 14 hold the permanent magnets 22 during a connection of the permanent magnets 22 to the yoke 16 by, for example, gluing, casting with a synthetic resin or overmolding with plastic.
• the yoke 16 with the permanent magnets 22 can, for example, also be inserted into a so-called protective tube (not shown). A rotor shaft (not shown) is pressed into the hole 12 for the manufacture of the rotor according to the invention or is used in another manner to prevent rotation.
• the back yoke 16 has two identical laminated cores 18, each with its own permanent magnet 22.
• the laminated cores 18 are twisted at an angle of for example 15 ° to each other, so that a generated by the permanent magnets 22 of the rotor magnetic pole having a quasi- ⁇ skew. This reduces the cogging torque and the torque wisdom of the rotor.
• the rotor can have more than two laminated cores 18 rotated relative to one another.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Permanent Field Magnets Of Synchronous Machinery (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=28458741

Family Applications (1)

Country Status (7)

Families Citing this family (31)

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• 2002
  • 2002-04-12 DE DE10216098A patent/DE10216098A1/de not_active Withdrawn
  • 2002-12-18 HU HU0500451A patent/HUP0500451A2/hu unknown
  • 2002-12-18 WO PCT/DE2002/004629 patent/WO2003088449A1/de active Application Filing
  • 2002-12-18 US US10/499,362 patent/US7154204B2/en not_active Expired - Fee Related
  • 2002-12-18 EP EP02795016A patent/EP1497901A1/de not_active Withdrawn
  • 2002-12-18 JP JP2003585257A patent/JP4373227B2/ja not_active Expired - Fee Related
  • 2002-12-18 CN CN02828740.1A patent/CN1625826B/zh not_active Expired - Fee Related

Non-Patent Citations (1)

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