WO2017125371A1 - Laminated rotor core for an electric machine - Google Patents

Abstract

The invention relates to a laminated rotor core (2) for an electric machine, wherein the laminated rotor core (2) comprises multiple laminations (7) stacked in a stack direction. The laminations (7) each have multiple openings (8) arranged in a circle, which connect the front sides of the respective lamination (7) to one another, and the laminations (7) each comprise multiple winding slots arranged in a circle. The openings (8) of the laminations (7) offset in the stack direction (L) are arranged offset to one another in a circumferential direction of the laminations (7) such that, with the winding slots being congruent, multiple screw spindle-shaped cooling channels (9) passing through the laminated rotor core (2) are formed. The winding slots of laminations (7) offset in the stack direction (L) are arranged offset to one another in the circumferential direction of the laminations (7) by at least one slot jump.

Description

description

Rotor sheet package for an electric machine The invention relates to a rotor core for an electric machine, in particular an air-cooled electric machine. Furthermore, the invention relates to a method for producing a rotor laminated core mentioned above. In electric machines, a performance limiting factor is the quality of dissipated heat dissipation. In particular, in embodiments in which temperature-stressed parts are not cooled directly by a cooling medium within the electrical machine, an utilization of active material used may not be optimal. Special zones, in which a dissipation of heat within an electrical machine can be problematic, are in particular stator winding heads and a rotor of the electric machine. Rotors for electrical machines are usually constructed from a rotor core, which is composed of individual stacked in the longitudinal ^¬ direction of the rotor plates. The individual sheets of the rotor laminated core are usually stacked congruent in the axial direction.

It is a further air-cooling of a rotor core packet ^¬ be known according to which two motor own fan, which are preferably molded to short-circuiting rings before ^¬ promote a cooling medium in two independent open circuits. After the cooling medium has absorbed heat of the rotor core, it is transported to the outside.

It is an object of the present invention to provide a rotor core of the type mentioned, which allows improved heat dissipation, in particular in the region of the rotor of an electrical machine, in particular in an air-cooled electric machine, and thereby enables an increase in the output of the electric machine with a constant overall volume.

The object is solved by the subject matters of the independent claims. Advantageous embodiments are subject of the dependent claims, the following description and the figures.

The rotor core of the invention for an electrical machine, in particular an air-cooled electric machine, comprises a plurality of sheets stacked in a stacking direction. The sheets each have a plurality of annularly arranged

Openings on which connect the end faces of the respective sheet together. Furthermore, the sheets each comprise a plurality of annularly arranged winding grooves. The

Breakthroughs offset in the stacking direction sheets are arranged offset in a circumferential direction of the sheets to each other such that at the same winding grooves a plurality of extending through the rotor core, helical spindle-shaped cooling channels are formed. The winding grooves of sheets offset in the stacking direction are offset in the circumferential direction of the sheets by at least one groove jump. Furthermore, the winding grooves and the apertures are arranged equidistant from each other, and the slope of the cooling channels is dependent on the number of groove jumps around which the apertures in the circumferential direction of the sheets are offset from each other, a pitch of the openings T _D and a pitch of the winding grooves T _w ,

The stacking direction extends in particular in a longitudinal direction of the rotor. The sheets are each individual Sheets, in particular congruent sheets, which have identical surfaces. With particular preference, all the laminations of the rotor laminations are identical in construction, that is to say they are identical components. The sheets are also preferably substantially annular, so that the rotor laminated core is in particular ^¬ special of a substantially hollow cylindrical shape.

The sheets each comprise a plurality of annularly arranged recesses which form the winding grooves of the individual sheets or the laminated core. Preferably, the winding grooves are arranged equidistant from one another and along an outer circumference of the metal sheets. Each sheet of the rotor lamination stack comprises a plurality of apertures which can be arranged between the outer circumference of the sheet, in particular between the winding grooves arranged there, and a central bore of the sheet for supporting the sheet on a rotor shaft.

Furthermore, the winding grooves of staggered sheets in the stacking direction are arranged offset in the same direction winding grooves in a circumferential direction of the sheets to each other. By "congruent" is meant in this context that the imaginary circular rings, along which the winding grooves are arranged, each congruent from one sheet to an immediately adjacent sheet in the stacking direction one above the other In other words, the winding grooves of sheets offset in the stacking direction are twisted or arranged in relation to one another in such a way that a plurality of helical spindle-shaped cooling channels are formed as a whole, the design of the cooling channels based on the principle of the Archimedean screw. The openings are arranged equidistant from each other, whereby parallel cooling channels can be formed, which allow a particularly uniform heat dissipation from the rotor core. Between adjacent breakthroughs, the sheet each forms a spoke. The resulting spoke design according to this embodiment enables a high rotor rigidity and a high torque transmission. The winding grooves of offset in the stacking direction sheets are offset in the circumferential direction of the sheets by at least one groove jump. A groove jump here is the circumferential distance or the angular distance between two adjacent winding grooves to each other. This unit for displacement or staggered arrangement allows a particularly simple and accurate production of the laminated core with trained by the breakthroughs screw-shaped cooling channels. Characterized in that the winding grooves and the apertures are arranged equidistant from each other, a particularly simple and easily calculable adaptation of the promotion of cooling medium (in particular gaseous media and aerosols) by the helical cooling channels or the removal of thermally laden coolant, for example air, allows what Furthermore takes place in dependence on a predetermined speed, an inner and outer diameter of the respective cooling channels, the Befüllgrades the cooling channels and the friction of the cooling medium in the helical spindle-shaped cooling channels.

The pitch of the cooling channels, in particular the pitch of a metal sheet to a staggered immediately adjacent in the stacking direction, arranged sheet metal (hereinafter: pitch per sheet SB), is dependent on the number x of the groove jumps around which the _n

 5

Breakthroughs in the circumferential direction of the sheets are arranged offset from one another, a pitch of the openings T _D and a pitch of the winding grooves T _w . The division of the breakthroughs T _D results from the full

Circumference (360 °) of the imaginary circular ring on which the openings are arranged, divided by the number of equidistantly distributed openings. If, for example, 6 openings are arranged in a circular ring, the result is a division of the openings T _D of 60 ° (= 360 ° / 6).

Similarly, the pitch of the winding grooves T _w results from the full circumference (360 °) of the imaginary annulus on which the winding grooves are located, divided by the number of equidistantly distributed winding slots. If, for example, 60 winding grooves are arranged in a circular ring, the result is a division of the winding grooves T _w of 6 ° (= 360 ° / 60).

The slope per sheet S _B can then be calculated using the following formula: S _B = T _D - x * T _w . The angular distance S _B p, which cover the cooling channels within the laminated core, resulting from the slope per sheet S _B multiplied by the number N of sheets of the laminated core, that is S _BP = S _B * N. Through the cooling channels of the rotor can gaseous cooling medium are passed, for example, a cooling air flow, wherein the cooling medium can be sucked from the environment of the rotor or the electric machine and released after flowing through the cooling channels back to the environment. Thus, a

Draft ventilation with an open circuit allows. As an alternative to a cooling air volume flow, the rotor laminated core with its helical spiral cooling channels is also adapted to a cooling medium such as, for example, oil (in particular high-viscosity oil or a gear oil) To promote oil foam or general aerosols through the cooling channels. Under certain conditions, a low-noise operation of the rotor or the electric machine is possible even at high bubble content.

If the rotor laminated core rotates during operation of the electric machine, the helical spindle-shaped cooling channels also rotate within the rotor laminated core. In this way, cooling medium can be conveyed through the cooling channels according to the principle of a screw pump, wherein the cooling channels serve as chambers of the screw pump for conveying cooling medium. The outer contour of the cooling channels is determined by the shape or the contour of the openings in the individual sheets. A possible flow can hereby be influenced in particular by the rotational speed of the rotor laminated core, the inner and outer diameters and in particular ^¬ sondere over the slope of the cooling channels as well as the friction of the cooling medium on the inner walls of the cooling channels. The rotor laminated core according to the invention enables a delivery of cooling medium and thereby a particularly intensive axial passage of cooling medium through the rotor laminated core and in particular ^¬ special an active cooling by a removal of thermally laden air. The helical shape of the

Cooling channel provides a particularly large Wärmeübertra ^¬ supply surface, whereby an improved Durchzugsbelüftete heat dissipation and cooling, in particular of the rotor is made possible. According to one embodiment, it is provided that the winding grooves of offset in the stacking direction sheets from a sheet to an immediately adjacent sheet in the circumferential direction of the sheets are offset from one another. By this arrangement, through the openings a cooling channel be formed with a particularly small pitch angle.

As a result, a volume flow of coolant conducted through the at least one cooling channel can flow past a particularly large surface of the cooling channel and thereby absorb a particularly large amount of heat from the rotor.

According to a further embodiment, it is provided that on a front side of the rotor laminated core, a fan impeller is arranged on ^¬ . By the fan wheel of the funded by the at least one cooling passage volume flow can be further increased. The fan impeller can be molded onto a short-circuit ring. "Integrally formed" is understood to mean in this context, in particular, are integrally connected to each other that the fan impeller is integrated into a short-circuit ring of the rotor, that is, the short-circuit ring and the fan impeller. This allows a reduction in weight of the rotor and a ge ^¬ ringeren production expense.

The air-cooled electric machine according to the invention comprises an above-described rotor core packet according to the invention.

The inventive method for producing a Ro ^¬ torblechpakets for an electrical machine, in particular an air-cooled electric machine, comprises providing a plurality of sheets. Several openings are punched in each of the sheets, so that the openings are annular and preferably arranged equidistant from each other. Furthermore, a plurality of winding grooves are punched in each of the sheets, so that the winding grooves are arranged annularly and preferably equidistant from each other. There is stacking of the sheets to a rotor core in a stacking direction, wherein the winding grooves of staggered in the stack direction sheets at congruent winding grooves in a circumferential direction of the sheets are offset from one another such that a plurality of screws ^¬ spindle-shaped cooling channels running through the rotor laminated core are formed. Furthermore, the winding grooves of offset in the stacking direction sheets in the circumferential direction of the sheets offset by at least one groove jump arranged to each other, the winding grooves and the openings are arranged equidistant from each other, and the slope of the cooling channels is dependent on the number of groove jumps to which the Breakthroughs in the circumferential direction of the sheets are arranged offset from one another, a division of

Breakthroughs and a division of the winding grooves.

In other words, the sheets are twisted to each other and stacked congruently. The sheets are in particular congruent sheets, each with several uniform breakthroughs. The twisting or staggered arrangement in the circumferential direction takes place about at least one groove of the rotor winding or at least one groove jump. The intended slope per sheet S _B , a length of the laminated core and / or the provided angular distance S _B p angular distance can be calculated or determined in advance and in particular the parameters division of the winding grooves T _w , pitch of the openings T _D , plate thickness of the individual sheets and their number be adjusted accordingly. Embodiments of the invention are explained in more detail below with reference to the schematic drawing. Hereby shows:

1 is a perspective view of a rotor comprising a rotor core with a plurality of screw-shaped cooling channels and a fan impeller,

2 is a plan view of a single sheet of Ro ^¬ torblechpakets of FIG. 1, 3 is a perspective view of a plurality of stacked sheets of the rotor laminated core of FIG. 1 with illustrated formation of the cooling channels, FIG. 4 is a partial longitudinal section through the rotor core of FIG. 1,

Fig. 5a, each a plan view of another

6a, 7a, rotor laminated core,

and 8a

5b, in each case a perspective view of a sheet metal 6b, 7b of the rotor laminated core according to FIGS. 6a, 7a and 8a with and 8b of a course of a cooling duct and FIG

Fig. 5c, in each case a perspective view of a plurality of sheets 6c, 7c of the rotor laminated core according to Fig. 6a, 7a and 8a.

and Fig. 8c shows a rotor 1 of an air-cooled electric machine (not shown). The rotor 1 comprises a rotor laminated core 2 and an impeller 3 with blades 4 shown on the left in FIG. 1. The rotor core 2 comprises a plurality of identical laminations 7 stacked one above the other in the longitudinal direction L of the rotor 1, wherein the laminations 7 each have seven apertures 8 and Openings 8 of all stacked sheets 7 a total of seven by the rotor laminated core 2 ver ^¬ running, screw-shaped cooling channels 9 form. Each of the seven punched apertures 8 of the plate 7 connects mutually opposite end faces S of the sheet 7 with each other and forms a portion of the seven mutually parallel, helical spindle-shaped Cooling channels 9, which arise from the fact that the individual sheets 7 are congruently stacked in the longitudinal direction L of the rotor 1 to the rotor core 2, each individual sheet

7 is arranged offset in the circumferential direction U to each other. The openings 8 are each on an imaginary inner annulus

10.1 of the sheets 7 are arranged. Between adjacent breakthroughs

8, the plate 7 forms a spoke 5 in each case. Further, the plate 7 has a plurality of radially outwardly extending, identical winding grooves 11 which are arranged equidistantly on an imaginary outer annulus 10.2 and distributed along an outer periphery 12 of the sheet 7 by a respective groove jump 13. The groove jump 13 here is the circumferential distance or the angular distance between two adjacent winding grooves 11 to each other.

As can be seen in particular from FIGS. 3 and 4, the sheets 7 are stacked in such a twisted relation to one another that the winding grooves 11 or the perforations 8 of sheets 7 offset in the stacking direction L (illustrated by way of example in FIG. 4 by the reference numerals "8a" and "8b" designated breakthroughs) in a circumferential direction U of the sheets 7 from a sheet to an immediately adjacent sheet (exemplified in Fig. 4 illustrated by the reference numerals "7a" and "7b" designated sheets) are offset from each other. The winding grooves 11 or the openings of the sheets stacked in the stacking direction L (for example the openings 8a, 8b) are arranged offset in the circumferential direction U of the sheets 7 by one groove jump 13 in each case. This results in a relatively small pitch angle of the cooling channel 9. The groove jump 13 represents the angular distance of two adjacent winding grooves 11. The openings 8 thereby form helical spindle-shaped cooling channels

9, wherein the course of one of these cooling channels 9 in the form of an Archimedean screw in Fig. 3 for clarity partially is shown without associated sheets 7. The cooling channels 9 are parallel to each other.

Fig. 5a shows a rotor core 2, which has been stacked from sheets 7 of FIG. The plates 7 have a total of 56 equidistant to each other on the outer annulus 10.2 arranged winding grooves 11. The seven openings 8 are also arranged equidistant from each other on the inner annulus 10.1.

Fig. 5b shows an example of the course of a cooling channel 9 of the seven identical and parallel to each other

The pitch of the cooling channels 9 from a sheet metal to an immediately adjacent in the stacking direction L sheet (hereinafter: pitch per sheet S _B ) is dependent on the number x of the groove jumps 13, by which the Wicklungsnuten or the openings in the circumferential direction of Plates 7 are offset from one another, a pitch of the openings T _D and a pitch of the winding grooves T _w .

The pitch of the apertures T _D results from the full circumference (360 °) of the inner annulus 10.1, on which the apertures are arranged, divided by the number of equidistant apertures 8. In the example shown by FIGS. 5a to 5c, 7 are Breakthroughs arranged in a circular ring. This results in a pitch of the openings T _D of 51, 428 ° (= 360 ° / 7).

Similarly, the pitch of the winding grooves T _{w is given} by the full circumference (360 °) of the outer annulus 10.2 on which the winding grooves 11 are located, divided by the number of equidistantly distributed winding slots 11. In FIG. 5a to 5c shown example are 56 winding grooves arranged in a circular ring. This results in a pitch of the winding grooves T _w of 6.499 ° (= 360 ° / 56).

The pitch per sheet S _B results from the formula S _B 1 DX * T _w and is for a groove jump or seven groove jumps 6, 429 °.

The laminated core shown by Fig. 5a comprises 100 sheets 7, each with a plate thickness of 0.5 mm. This results in a length of the laminated core 2 of 50 mm. The angular distance S _BP , which the cooling channels 9 - as shown by Fig. 5b - within the

Sheet pack 2, resulting from the slope per sheet S _B multiplied by the number N of the sheets 7 of the laminated core 2, that is S _BP = S _B * N and is 642, 9 °. Those shown by Figs. 6a to 6c, 7a to 7c and 8a to 8c

Sheet metal packages 2 are similar to the laminated core according to FIGS. 5 a to 5 c, in particular they have the same pitch of the winding grooves T _w (6, 429 °) and the same length of the laminated core (50 mm of 100 identical metal sheets 7 with a sheet thickness of 0 in each case , 5 mm). The laminated cores 2 shown by FIGS. 6a to 6c, 7a to 7c and 8a to 8c differ from the laminated core 2 shown by FIGS. 5a to 5c, however, with respect to the number of equidistant apertures 8 and the number x of groove jumps the openings 8 of staggered in the stacking direction L sheets 7 in the circumferential direction U of the sheets 7 are offset from one another.

In the example shown by Fig. 6a to 6c 10 openings are arranged in a circular ring. This results in a division of the openings T _D of 36 ° (360 ° / 10). The openings 8 of staggered in the stacking direction L sheets 7 are in the circumferential direction U of the sheets 7 to x = 5 groove jumps 13 and thus offset by 32, 145 ° to each other. The pitch per sheet S _B results from the formula S _B = T _D - x * T _w and is 3.855 °. The angular distance S _BP , which the cooling channels 9 - as shown by Fig. 6b - cover within the laminated core 2, resulting from the slope per sheet S _B multiplied by the number N of the sheets 7 of the laminated core 2, that is S _B p = S _B. * N and is 385.5 °. If one alternatively provided 6 instead of 10 breakthroughs, the result would be six groove jumps 13 a negative slope per sheet S _B of -2.574 ° and a negative angular distance S _BP of -257.4 °, that is, the cooling channels would be less steep in an opposite direction oriented compared to the above-described variant with 10 breakthroughs.

In the example shown by FIGS. 7a to 7c, 9 apertures are arranged annularly. This results in a division of the openings T _D of 40 ° (360 ° / 9). The openings 8 of offset in the stacking direction L sheets 7 are in the circumferential direction U of the sheets 7 to x = 6 groove jumps 13 and thus offset by 38, 574 ° to each other. The pitch per sheet S _B results from the formula S _B = T _D - x * T _w and is 1.426 °. The angular distance S _BP , which the cooling channels 9 cover, as shown by FIG. 7b, within the laminated core 2, results from the pitch per sheet S _B multiplied by the number N of sheets 7 of the laminated core 2, ie S _BP = S _B * N and is 142.6 °.

In the example shown by Fig. 8a to 8c 11 openings are arranged in an annular shape. This results in a division of the openings T _D of 32.727 ° (360 ° / ll). The openings 8 of offset in the stacking direction L sheets 7 are in the circumferential direction U of the sheets 7 to x = 5 groove jumps 13 and thus offset by 32.145 ° to each other. The slope per sheet S _B results from the formula S _B = T _D - x * T _w and is 0.582 °. The angular distance S _BP , which the cooling channels 9 cover, as shown by FIG. 8b, within the laminated core 2, results from the pitch per sheet S _B multiplied by the number N of sheets 7 of the laminated core 2, ie S _BP = S _B * N and is 58.2 °.

Claims

claims 1. rotor laminated core (2) for an electric machine, wherein - The rotor core (2) comprises a plurality of stacked in a stacking direction (L) sheets (7),  - The sheets (7) each have a plurality of annularly arranged openings (8) which connect the end faces (S) of the respective sheet (7),  - The sheets (7) each comprise a plurality of annularly arranged winding grooves (11),  - The openings (8) offset in the stacking direction (L) sheets (7) in a circumferential direction (U) of the sheets (7) are offset from one another such that at the same winding grooves (11) more through the rotor core (2) extending , screw-spindle-shaped cooling channels (9) are formed,  - The winding grooves (11) of in the stacking direction (L) staggered sheets (7) in the circumferential direction (U) of the sheets (7) offset by at least one groove jump (13) are arranged mutually,  - The winding grooves (11) and the openings (8) are arranged equidistant from each other, and - The slope of the cooling channels (9) is dependent on the number of groove jumps (13) by which the openings (8) in the circumferential direction (U) of the sheets (7) are arranged offset to one another, a pitch of the openings T _D and a division of the winding grooves T _w . 2. rotor laminated core (2) according to claim 1, characterized in that the winding grooves (11) offset in the stacking direction (L) sheets (7) of a sheet (7 a) to an immediately adjacent plate (7 b) in the circumferential direction (U ) of the sheets (7a, 7b) are arranged offset from one another. 3. rotor laminated core (2) according to one of the preceding claims, characterized in that on one end side of the Rotorb ^¬ lechpakets (2) a fan impeller (3) is arranged. 4. An air-cooled electric machine comprising a Ro ^¬ torblechpaket (2) according to any one of the preceding claims. 5. A method for producing a rotor lamination stack (2) according to one of the preceding claims, comprising the method steps:  - Providing a plurality of sheets (7),  Punching a plurality of openings (8) in each of the sheets (7), so that the openings (8) are arranged annularly, - punching a plurality of winding grooves (11) in each of the sheets (7), so that the winding grooves (11) are arranged annularly, Stacking of the sheets (7) to form a laminated rotor core (2) in a stacking direction (L), wherein the apertures (8) of sheets (7) offset in the stacking direction (L) coincide with winding slots (11) in a circumferential direction (U) the sheets (7) are arranged offset from one another in such a way that a plurality of helical spindle-shaped cooling channels (9) extending through the rotor laminated core (2) are formed, and  the winding grooves (11) of sheets (7) offset in the stacking direction (L) in the circumferential direction (U) of the sheets (7) are offset by at least one groove jump (13), wherein the winding grooves (11) and the apertures (8) are arranged equidistant from each other, and the pitch of the cooling channels (9) is dependent on the number of groove jumps (13) around which the openings (8) in the circumferential direction (U) of the sheets (7) offset from one another, a pitch of the openings T _D and a pitch of the winding grooves T _w .