WO2015003738A1

WO2015003738A1 - Rotary electrical machine stator core lamination and method of manufacturing thereof

Info

Publication number: WO2015003738A1
Application number: PCT/EP2013/064396
Authority: WO
Inventors: Hakan Gedik; Metin OZBAGRIACIK; Onur UZER; Erdem SEVGEN
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2013-07-08
Filing date: 2013-07-08
Publication date: 2015-01-15
Anticipated expiration: 2016-01-08
Also published as: EP3020120A1

Abstract

The present invention relates to an electrical machine having a stator (1) and an inner rotor disposed in a space formed inside the stator (1) and rotatable with respect to the stator (1) in a manner connected to a shaft, said stator (1) having a plurality of laminations (2) stamped out in an identical manner and stacked one above the other, each lamination (2) having a plurality of inwardly projecting teeth (3) extending successively along an inner periphery of the stator (1) to form winding slots (4) that receive windings of the stator (1).

Description

ROTARY ELECTRICAL MACHINE STATOR CORE LAMINATION AND METHOD OF MANUFACTURING THEREOF

The present invention relates to rotary electrical machines and more particularly stator core lamination pole structures of such rotary electrical machines.

Electric machines rely on the principle of rotating magnetic fields with a magnetic part or rotor. For instance, AC electric motors comprises rotor or a configuration of insulated wire coils in a stationary part, i.e. the stator. Current flow generates magnetic fields in the space of the stator. Stator casings are made from ferromagnetic laminates and longitudinal slots in the stator casing define tooth-like cross sections, i.e. poles.

Electrical machines, such as electric motors or alternators are extensively known to the person in the art. The stator of such machines comprises core slots along which a stator coil is disposed, a plurality of teeth being connected to the stator core by a yoke portion. The cylindrical stator core is provided with a longitudinal hole inside which the rotor is housed. The stator windings are disposed in a plurality of core slots formed by radially extending layers such that straight portions of the windings extend in the slots and end loop sections thereof connect two adjacent straight portions.

The stator core is typically formed to comprise a plurality of laminations of a ferromagnetic material, said laminations being stacked consecutively. A coaxial lamination stack has identical laminations in abutment with one another in the manner that an inner periphery defined by an array of inwardly projecting teeth is formed. In other words, each lamination comprises an annular peripheral portion having a plurality of projections in the form of teeth so as to be extending towards the longitudinal axis of the stator core.

A prior art publication in the technical field of the present invention may be referred to as US3777198, disclosing a coil positioned in the slot of a stator or rotor in an electric machine and formed of a bundle of conductors arranged close together and insulated from each other and from the slot.

The present invention provides an electrical machine having a stator in which laminations are stacked one above the other in such a manner that the stator slots are naturally closed by the stator teeth themselves, eliminating the need for using special covers or insulation elements in this effect. It is known that such covers may damage windings during installation and special cover designs are considered to minimize contact with windings during installation of the covers.

The present invention therefore provides an electrical machine with a stator in which the winding slots are closed by the stator teeth themselves as defined by the characterizing features as given in Claim 1.

Primary object of the present invention is to provide an electrical machine with a stator in which no special winding slot closing means is required.

The present invention proposes an electrical machine having a stator and a rotor. A plurality of identical laminations, with a plurality of inwardly projecting teeth is stacked one above the other. Said inwardly projecting teeth comprise L-form claw portions, the shorter extensions in the L-shape structures protruding in a peripheral direction forming end parts of the teeth. Each lamination or group of laminations is successively stacked such that every second successive lamination is reversed before assembling. Said claw portions of the teeth are therefore pointed to opposite directions in neighboring laminations or groups of laminations.

The present invention further proposes a method for assembling a stator of an electrical machine, said method comprising the steps of assembling each lamination or group of laminations in a successive manner by reversing every second successive lamination or group of lamination, placing stator windings inside winding slots and rotating every second successive lamination or group of lamination by a distance equal to the length of an inner peripheral edge of the claw portions.

Accompanying drawings are given solely for the purpose of exemplifying the electrical machine of the present invention whose advantages over prior art were outlined above and will be explained in brief hereinafter.

The drawings are not meant to delimit the scope of protection as identified in the claims nor should they be referred to alone in an effort to interpret the scope identified in said claims without recourse to the technical disclosure in the description of the present invention.

Fig. 1 demonstrates a top planar view of two stator laminations according to the present invention.

Fig. 2 demonstrates a top planar view of the stator laminations shown in Fig. 1 as stacked one above the other according to the present invention.

Fig. 3 demonstrates a front planar view of a stator lamination tooth according to the present invention.

Fig. 4 demonstrates a top planar view of a plurality of stator laminations stacked one above the other with non-aligned slot bases and non-closed slot openings to enable placement of stator windings according to the present invention.

Fig. 5 demonstrates a general perspective view of a plurality of stator laminations shown in Fig. 4.

Fig. 6 demonstrates a top planar view of a plurality of stator laminations stacked one above the other with aligned slot bases and closed slot openings according to the present invention.

Fig. 7 demonstrates a general perspective view of a plurality of stator laminations shown in Fig. 6.

Fig. 8 demonstrates an enlarged portion of the stator laminations shown in Fig. 5.

Fig. 9 demonstrates an enlarged portion of the stator laminations shown in Fig. 7.

The following numerals are used in this detailed description:

Stator
Core lamination
Teeth
Winding slot
Claw portion
Inner peripheral edge
Front face
Rear face
Slot base
Slot opening
Side surface

The present invention provides an electrical machine typically having a stator (1) and an inner rotor disposed in a space formed on an inner side of the stator (1) to enable rotation of the rotor with respect to the stator (1) in a manner conventionally connected to a shaft. The stator (1) has a stack of laminations (2), i.e. a plurality of laminations (2) stacked one above the other, the individual laminations (2) being stamped out so as to be identical.

Each lamination (2) has a set of inwardly projecting teeth (3) extending successively along the inner periphery of the stator (1) to form winding slots (4) that receive windings of the stator (1). To this end, laminations (2) are aligned such that said inwardly projecting teeth (3) of the laminations (2) longitudinally define the axially extending winding slots (4) receiving the stator (1) windings.

The teeth (3) of each lamination (2) and the winding slots (4) are aligned such that claw portions (5) of the teeth (3) in a first lamination (2) or group of laminations (2) are oriented oppositely with respect to claw portions (5) of the teeth (3) of an adjacent lamination (2) or group of laminations (2). Said claw portions (5) constitute end extensions of the teeth (3) that protrude in a peripheral direction. Each claw portion (5) in a tooth is identical such that it protrudes in a substantially symmetrical orientation on one side of the tooth (3).

According to the present invention, each of the teeth (3) has a front face (7) and a rear face (8), said front and rear faces (7, 8) facing opposite directions along the longitudinal axis of the stator (1). The teeth (3) have side surfaces (11) sloping from a slot base (9) portion between neighboring teeth (3) of a lamination (2). The claw portions (5) are formed only at one of two sides of the teeth (3). The side surfaces (11) are shaped in an inclined manner to form a narrowing tooth (3) structure leading to the claw portion (5).

According to the present invention, a lamination (2) stack is assembled such that each succeeding lamination (2) or succeeding group of lamination (2), i.e. every second lamination (2) or group of lamination (2) in the stack, is rotated by a distance equal to the length of an inner peripheral edge (6) of the claw portions (5) after the stator windings are placed inside the stator slots (4), said inner peripheral edge (6) portions extending perpendicular to the radial directions around the stator (1) axis.

In this regard, a plurality of stator (1) laminations (2) are first stacked one above the other in a successively reversed manner while neighboring laminations (2) are oriented to have non-aligned slot bases (9) with respect to each other and then every second lamination (2) in the stack is radially displaced, i.e. rotated such that winding slots’ (4) openings (10) are closed by the claw portions (5) of the teeth (3).

In a nutshell, the present invention proposes an electrical machine stator (1) having a plurality of laminations (2) stamped out in an identical manner and stacked one above the other, each lamination (2) having a plurality of inwardly projecting teeth (3) extending successively along an inner periphery of the stator (1) to form winding slots (4) that receive windings of the stator (1).

The inwardly projecting teeth (3) comprise claw portions (5) protruding in a peripheral direction in the form of end extensions of the teeth (3) and each lamination (2) or group of laminations (2) are successively stacked one above the other such that each first lamination (2) or group of laminations is assembled to an adjacent second lamination (2) or group of laminations in a reversed manner. Said claw portions (5) of the teeth (3) in a first lamination (2) or group of laminations (2) are oppositely oriented with respect to the claw portions (5) of the teeth (3) of an adjacent lamination (2) or group of laminations (2). The claw portions (5) of the teeth (3) protrude on one side of the tooth (3) so as to form an L-shaped tooth structure.

The present invention further proposes a method for assembling a stator (1) of an electrical machine, said method comprising the steps of (a) assembling each lamination (2) or group of laminations (2) in a successive manner by way of reversing each succeeding lamination (2) or group of laminations (2), (b) fixating successively assembled lamination (2) or group of laminations (2) in the axial direction of the stator (1), (c) placing stator windings inside said winding slots (4), (d) rotating each succeeding lamination (2) or succeeding group of lamination (2) by a distance equal to the length of an inner peripheral edge (6) of the claw portions (5) and (e) fixating successively assembled lamination (2) or group of laminations (2) in the radial direction of the stator (1).

The slot bases (9) of successively reversed individual laminations (2) or group of laminations (2) being non-aligned serves to the purpose of placing stator (1) windings in a convenient manner. Thereupon, every second successive lamination (2) or group of laminations (2) is displaced by a distance equal to the length of an inner peripheral edge (6) of the claw portions (5). This, while overcoming misalignment of the winding slots (4) between two adjacent laminations (2) or groups of laminations (2), ensures that the winding slots’ (4) openings (10) are closed by the claw portions (5) of the teeth (3). The stator’s (1) winding slots (4) are therefore closed by the stator (1) teeth (3) themselves, eliminating the need for using special covers or insulation elements in this effect.

Claims

An electrical machine having a stator (1) and an inner rotor disposed in a space formed inside the stator (1) and rotatable with respect to the stator (1) in a manner connected to a shaft, said stator (1) having a plurality of laminations (2) stamped out in an identical manner and stacked one above the other, each lamination (2) having a plurality of inwardly projecting teeth (3) extending successively along an inner periphery of the stator (1) to form winding slots (4) that receive windings of the stator (1), characterized in that

said inwardly projecting teeth (3) comprise claw portions (5) protruding in a peripheral direction in the form of end extensions of the teeth (3),

each lamination (2) or group of laminations (2) are successively stacked one above the other such that each first lamination (2) or group of laminations is assembled to a second adjacent lamination (2) or group of laminations in a manner reversed with respect to each other.
An electrical machine as in Claim 1, characterized in that said claw portions (5) of the teeth (3) in a first lamination (2) or group of laminations (2) are oppositely oriented with respect to the claw portions (5) of the teeth (3) of an adjacent lamination (2) or group of laminations (2).
An electrical machine as in Claim 1 or 2, characterized in that the claw portions (5) of the teeth (3) protrude on one side of the tooth (3) so as to form an L-shaped tooth structure.
A method for assembling a stator (1) of an electrical machine, the stator (1) having a plurality of laminations (2) stamped out in an identical manner and stacked one above the other, each lamination (2) having a plurality of inwardly projecting teeth (3) extending successively along an inner periphery of the stator (1) to form winding slots (4) that receive windings of the stator (1), the inwardly projecting teeth (3) comprising claw portions (5) protruding in a peripheral direction in the form of end extensions of the teeth (3), said method comprising the steps of:

a) assembling each lamination (2) or group of laminations (2) in a successive manner by way of reversing every second successive lamination (2) or group of laminations (2),

b) fixating successively assembled lamination (2) or group of laminations (2) in the axial direction of the stator (1),

c) placing stator windings inside said winding slots (4),

d) rotating every second successive lamination (2) or group of lamination (2) by a distance equal to the length of an inner peripheral edge (6) of the claw portions (5) and,

e) fixating successively assembled lamination (2) or group of laminations (2) in the radial direction of the stator (1).