CN112771757A

CN112771757A - Stator core assembly

Info

Publication number: CN112771757A
Application number: CN201980064105.4A
Authority: CN
Inventors: 陈宇; M.霍瓦特
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2018-09-28
Filing date: 2019-08-27
Publication date: 2021-05-07
Anticipated expiration: 2039-08-27
Also published as: CN112771757B; GB2577546B; GB201815845D0; WO2020065254A1; GB2577546A

Abstract

A stator core assembly (10) for a permanent magnet electric machine (100) has a stator core (12), a bobbin (14) on which the stator core (12) is mounted, and a coil (16) wound around the bobbin (16). A first side (40) of the spool (14) has a primary channel (42) and a second side (43) of the spool (14) has a first secondary channel (46) and a second secondary channel (48). The coil (16) is wound around the bobbin (14) such that at least a portion of the coil (16) extends between the primary channel (42) and the first secondary channel (46), and at least a portion of the coil (16) extends between the primary channel (42) and the second secondary channel (48).

Description

Stator core assembly

Technical Field

The present invention relates to a stator core assembly and more particularly, but not exclusively, to a stator core assembly for a permanent magnet electric machine.

Background

Permanent magnet electric machines typically comprise a rotor assembly and one or more stator core assemblies for causing rotation of the rotor assembly in use.

It is generally desirable to improve permanent magnet machines in a number of ways, including, for example, size, weight, manufacturing cost, efficiency, reliability, and noise.

Disclosure of Invention

According to a first aspect of the present invention there is provided a stator core assembly for a permanent magnet electric machine, the stator core assembly comprising a stator core, a bobbin on which the stator core is mounted, and a coil wound around the bobbin, wherein a first side of the bobbin comprises a primary channel, a second side of the bobbin comprises first and second secondary channels, and the coil is wound around the bobbin such that at least a portion of the coil extends between the primary channel and the first secondary channel and at least a portion of the coil extends between the primary channel and the second secondary channel.

The stator core assembly according to the first aspect of the present invention may in principle be advantageous in that the first side of the bobbin comprises a main channel, the second side of the bobbin comprises a first and a second secondary channel, and the coil is wound around the bobbin such that at least a part of the coil extends between the main channel and the first secondary channel and at least a part of the coil extends between the main channel and the second secondary channel.

In particular, this may reduce the temperature during use relative to a bobbin having only a single secondary channel of the same width as its primary channel, as a larger surface area of the coil may be exposed and thus may pass cooling air flow in use.

The stator core assembly according to the first aspect of the invention may also provide for better alignment of the coils than for example arrangements where there is a single passage on each side of the bobbin and extends across the entire width of the bobbin. By dividing the coil between the first and second secondary channels, each of the first and second secondary channels may contain fewer coil turns than an arrangement using a single secondary channel extending along the entire width of the bobbin, allowing for better alignment and tighter control of the coil within the respective channels. Better alignment of the coils may result in greater consistency of the windings, for example during production of the stator assembly, which may result in better tolerances.

The first side of the bobbin may comprise a side of the bobbin opposite the second side of the bobbin. For example, the first side and the second side may face in opposite directions.

The main passage may comprise a passage closest to the permanent magnets of the permanent magnet machine when the stator core assembly is installed in the permanent magnet machine. The secondary channel may comprise the channel of the permanent magnet furthest from the permanent magnet of the permanent magnet machine when the stator core assembly is installed in the permanent magnet machine. The terms "primary channel" and "secondary channel" may refer to, for example, radially inner and outer channels relative to the permanent magnets of a permanent magnet machine when the stator core assembly is installed in a permanent magnet machine. The first side of the bobbin may be referred to as an inner side of the bobbin and the second side of the bobbin may be referred to as an outer side of the bobbin.

The stator core may include first and second pole arms, and a core back (flyback) connecting the first and second pole arms. The stator core may be mounted to the bobbin such that the primary channel is located between the first and second pole arms and the first and second secondary channels are located on a core back of the stator core.

The spool may include first and second end walls and an intermediate wall that may define the first and/or second secondary passages. For example, the first end wall and the intermediate wall may define a first secondary channel, and/or the intermediate wall and the second end wall may define a second secondary channel. The intermediate wall may have substantially the same depth as the first and/or second end wall. This may be beneficial because the first and/or second secondary channels may be defined over substantially the entire depth of the bobbin, thereby better aligning the coil over substantially the entire depth of the bobbin. The depth of the bobbin may include a dimension of the bobbin in a direction substantially parallel to a direction in which the pole arms of the stator core extend. The first and second end walls may be located on the first and second sides of the bobbin, and/or the intermediate wall may be located only on the second side of the bobbin.

The first and second end walls and the intermediate wall may collectively provide the second side of the bobbin with a generally E-shaped or W-shaped cross-sectional shape. At least a portion of the bobbin may include a generally E-shaped or W-shaped cross-sectional shape. The primary channel may include a generally C-shaped cross-sectional shape, such as a C-shaped cross-section defined by a flat edge. The coil may be wound around the bobbin such that the coil has a generally V-shaped profile when viewed from a direction along the length of the stator core assembly. For example, the turns of the coil may define a V-shape when viewed from a direction along the length of the stator core assembly. The stator core may include a generally C-shaped cross-sectional shape and may be referred to as a C-shaped stator core, for example. Each secondary channel may include a generally C-shaped cross-sectional shape, such as a C-shaped cross-sectional shape defined by a flat edge. The cross-sectional shapes discussed above may include shapes viewed in cross-section taken in a plane orthogonal to the longitudinal axis of the spool.

The coil may be wound around the bobbin such that at least one turn of the coil extends along the primary and first secondary channels and at least one turn of the coil extends along the primary and second secondary channels. The turns of the coil may comprise a substantially closed loop of the coil, e.g. a complete rotation of the coil bobbin.

The primary and/or secondary channels may be of substantially elongate form, for example having a length greater than its width and/or depth. Each of the primary and secondary channels may extend beyond the stator core, for example in the longitudinal direction.

The primary channel may comprise a single channel, for example a channel defined by two end walls and a base wall, with substantially no intervening walls or protrusions between the end walls and the base wall. This may be beneficial because a higher fill factor may need to be provided on the first side of the bobbin (e.g., between the pole arms of the stator core), and a single channel may achieve a higher fill factor than, for example, multiple channels defined by walls within the space between the pole arms of the stator core. The single channel may comprise a channel defined by two end walls and a base wall, with substantially no protrusions or intervening walls between the end walls and the base wall having a depth greater than one quarter of the depth of the wire forming the coil.

The first and second secondary channels may extend over substantially the entire second side of the bobbin, e.g. over substantially the entire core back of the stator core. This is beneficial compared to arrangements where the channels are limited to only a region of the second side of the bobbin (i.e. only a region of the core back of the stator core) as the overall depth of the coil is reduced when wound around the bobbin. This may reduce the overall depth of the stator assembly. This may be beneficial when the stator assembly is installed in a permanent magnet electric machine in use, as it may reduce the amount of the stator assembly that is exposed to the airflow through the electric machine in use, thereby providing improved air efficiency and/or improved acoustic results. By having the first and second secondary passages extend over substantially the entire second side of the bobbin, the exposed surface area of the coil can be increased and the stator assembly can therefore benefit from a reduction in temperature in use.

The combined width of the first and second secondary channels may be greater than the width of the primary channel. Each of the first and second secondary channels may have a width substantially the same as a width of the main channel. The width may, for example, comprise a width in a direction substantially orthogonal to a direction in which the pole arms of the stator core extend.

The first and second end walls may be substantially aligned with edges of the first and second pole arms. For example, the outermost edges of the first and second end walls may be substantially aligned with the outermost edges of the first and second pole arms. The first and second end walls may define a substantially continuous surface with the respective first and second pole arms. This may be beneficial because it may remove corners and/or sharp edges from the stator assembly, and this may improve better air efficiency when mounting the stator assembly in an electric machine in use.

The first and second secondary channels may comprise substantially the same dimensions, for example substantially the same width and/or height and/or depth. The intermediate wall may be located at a midpoint between the first end wall and the second end wall. The intermediate wall may be located at a midpoint of a core back of the stator core. The size of the coil portion contained within the first secondary channel may be substantially the same as the size of the coil portion contained within the second secondary channel. For example, the first secondary channel may accommodate substantially the same number of coil turns as the second secondary channel. This may be beneficial as it may allow the temperature distribution to be uniform throughout the bobbin in use.

The bobbin may include slots in which the stator core is received. The bobbin may include a first bobbin portion and a second bobbin portion, each bobbin portion having a slot for receiving a respective end of the stator core. The first and second bobbin portions may sandwich the stator core.

Each of the first and second spool portions may define a corresponding portion of the primary passageway, a corresponding portion of the first secondary passageway, and a corresponding portion of the second secondary passageway.

The coil may comprise a single coil, for example, a continuous coil defined by a single wire winding.

The coil may comprise a single phase winding or a three phase winding.

The spool may include a third secondary channel, or indeed any number of other secondary channels. However, it will be appreciated that a balance needs to be struck between the required number of secondary channels and the available space to achieve the desired number of turns without increasing the size, e.g. depth, of the stator assembly.

According to a second aspect of the present invention there is provided a permanent magnet electric machine comprising a stator core assembly according to the first aspect of the present invention.

According to a third aspect of the present invention there is provided a vacuum cleaner comprising a permanent magnet motor according to the second aspect of the present invention.

According to a fourth aspect of the present invention there is provided a method of manufacturing a stator core assembly, the method comprising providing a stator core and a bobbin, the bobbin having a first side and a second side, the first side comprising a primary channel and the second side comprising first and second secondary channels, the stator core being mounted to the bobbin; the coil is wound around the bobbin such that at least a portion of the coil extends between the primary channel and the first secondary channel and at least a portion of the coil extends between the primary channel and the second secondary channel.

The stator core may include first and second pole arms connected by a core back, and the stator core may be mounted to the bobbin such that the primary channel is located between the first and second pole arms of the stator core and the first and second secondary channels are located on the core back of the stator core.

The method may include winding the coil around the bobbin such that the coil is evenly divided between the first and second secondary passages.

The method may comprise winding the coil around the bobbin such that the coil has a generally V-shaped profile when viewed in a direction parallel to the longitudinal axis of the bobbin, for example in a cross-section taken in a plane orthogonal to the longitudinal axis of the bobbin.

The method may include alternately winding the coil between the primary channel and the first secondary channel and between the primary channel and the second secondary channel. For example, the method may include: the method may include winding a first turn of the coil between the primary channel and the first secondary channel, then winding a second turn of the coil between the primary channel and the second secondary channel, then winding a third turn of the coil between the primary channel and the first secondary channel, and so on, until the desired number of turns is completed, or the method may include winding a first row of turns of the coil between the primary channel and the first secondary channel, then winding a second row of turns of the coil between the primary channel and the second secondary channel, then winding a third row of turns of the coil between the primary channel and the first secondary channel, and so on, until the desired number of rows of turns is completed.

The method can comprise the following steps: winding a coil between the main tunnel and the first secondary tunnel until the first secondary tunnel is filled to a predetermined level; subsequently, a coil is wound between the primary and secondary channels until the secondary channel is filled to a predetermined level.

The method may include mounting the stator core to the bobbin such that the primary channel is located between the first and second pole arms of the stator core and the first and second secondary channels are located on the core back of the stator core.

Preferred features of each aspect of the invention may be equally applicable to other aspects of the invention where appropriate.

Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

FIG. 1 is a perspective view of a stator core assembly according to the present invention;

FIG. 2 is a perspective view of a stator core of the stator core assembly of FIG. 1;

FIG. 3 is a schematic cross-sectional view of the stator core of FIG. 2;

FIG. 4 is an exploded perspective view of the bobbin of the stator core assembly of FIG. 1;

FIG. 5 is a first perspective view of the spool of FIG. 4;

FIG. 6 is a second perspective view of the spool of FIG. 4;

FIG. 7 is a first perspective view of the bobbin of FIG. 4 in combination with the stator core of FIG. 2;

FIG. 8 is a second perspective view of the bobbin of FIG. 4 in combination with the stator core of FIG. 2;

FIG. 9 is a schematic cross-sectional view of the stator assembly of FIG. 1;

figure 10 is a schematic cross-sectional view showing a first winding pattern of the stator assembly of figure 1;

figure 11 is a schematic cross-sectional view illustrating a second winding pattern of the stator assembly of figure 1;

figure 12 is an exploded perspective view of a permanent magnet electric machine including the stator assembly of figure 1;

figure 13 is a perspective view of a vacuum cleaner incorporating the permanent magnet motor of figure 12; and

fig. 14 is a flow chart schematically illustrating a method of manufacturing the stator assembly of fig. 1.

Detailed Description

A stator core assembly in accordance with a first aspect of the present invention is shown in fig. 1 and generally indicated by reference numeral 10.

The stator core assembly 10 includes a stator core 12, a bobbin 14, and a coil 16.

The stator core 12 is shown separately in fig. 2 and 3 and includes first and

second pole arms

18, 20 and a core back 22 connecting the first and

second pole arms

18, 20. The stator core 12 has a substantially C-shaped sectional shape, for example, when viewed in a section taken in a direction substantially orthogonal to the longitudinal axis of the stator core 12, and therefore, the stator core 12 may be referred to as a C-shaped stator core. Although not shown in the drawings, the stator core 12 is formed of a plurality of laminated layers that are stacked one on top of the other. First and second locating

projections

24, 26 extend outwardly from the stator core 12 near the interfaces between the respective first and

second pole arms

18, 20 and the core back 22 and serve to locate the stator core assembly 10 relative to the frame 102 of the permanent magnet electric machine 100.

The spool 14 is shown in isolation in fig. 4-6 and includes a first spool portion 28 and a second spool portion 30. Each

bobbin section

28, 30 has respective first and

second end walls

32, 34, a base wall 36 and a stator core receiving slot 38. The base wall 36 extends between the first and

second end walls

32, 34 and functions to space the first and

second end walls

32, 34 apart. The first side 40 of each

bobbin portion

28, 30 thus includes a respective portion of the primary coil receiving channel 42 defined by the first and

second end walls

32, 34 and the base wall 36.

Second side 43 of each spool portion has an intermediate wall 44 extending from base wall 36 at about the midpoint between first end wall 32 and second end wall 34. The second side 43 of each

bobbin portion

28, 30 thus includes corresponding portions of first and second secondary coil-receiving

channels

46, 48 defined by the first and

second end walls

32, 34, the base wall 36 and the intermediate wall 44.

Intermediate wall 44 has substantially the same height as first end wall 32 and second end wall 34. The spacing of the first and

second end walls

32, 34 varies around the perimeter of each

bobbin portion

28, 30 such that the outer edges of the first and

second end walls

32, 34 on the first side 40 of the

bobbin portions

28, 30 are spaced apart by a distance substantially corresponding to the spacing between the inner edges of the first and

second pole arms

18, 20 of the stator core 12, and the outer edges of the first and

second end walls

32, 34 on the second side 43 of the

bobbin portions

28, 30 are spaced apart by a distance substantially corresponding to the spacing between the outer edges of the first and

second pole arms

18, 20 of the stator core 12, i.e., corresponding to the width of the core back 22 of the stator core 12. More simply stated, the width of the base wall 36 increases between the first and

second sides

40, 43 of the

spool portions

28, 30.

The stator core receiving slot 38 is substantially rectangular in shape and is shaped and sized to receive a portion of the core back 22 of the stator core 12. In particular, the height of each stator core receiving slot 38 substantially corresponds to the thickness of the core back 22 of the stator core 12. As shown in fig. 1 and 8, each slot 38 has a length such that the first bobbin portion 28 and the second bobbin portion 30 substantially surround the core back 22 of the stator core 12 as a whole when assembled. The first and

second spool portions

28, 30 may not be of equal length, for example, the first spool portion 28 may be longer than the second spool portion 30, and thus the corresponding slots 38 may also be of different lengths.

As can be seen from fig. 7, when the slots 38 receive the core back 22 of the stator core 12, the first bobbin portion 28 and the second bobbin portion 30 effectively sandwich the stator core 12. The first bobbin portion 28 and the second bobbin portion 30 are held in place around the stator core 12 by an adhesive (not shown). The first side 40 of each

bobbin portion

28, 30 is received between the first pole arm 18 and the second pole arm 20 of the stator core 12 such that the primary coil receiving channel 42 is located between the first pole arm 18 and the second pole arm 20. The second side 43 of each

bobbin portion

28, 30 is received on the core back 22 of the stator core 12 such that the first secondary coil-receiving passage 46 and the second secondary coil-receiving passage 48 are located on the core back 22 of the stator core 12.

The coil 16 is a single phase winding typically used in single phase brushless permanent magnet motors. As can be seen from fig. 9 to 11, the coil 16 is wound around the bobbin 14 such that at least a portion of the coil 16 extends between the primary coil receiving channel 42 and the first secondary coil receiving channel 46, while the remainder of the coil 16 extends between the primary coil receiving channel 42 and the second secondary coil receiving channel 48. This makes the entire winding of the coil 16V-shaped when viewed in cross-section, as shown in fig. 9-11.

The coil 16 may be wound around the bobbin 14 in different ways, as shown in fig. 10 and 11. In fig. 10, it can be seen that the coil 16 is wound around the bobbin 14 so as to first fill the first secondary coil-receiving passage 46 and then refill the second secondary coil-receiving passage 48. In fig. 11, it can be seen that the coil 16 is wound around the bobbin 14 so as to form a first row of turns in the first secondary coil-receiving passage 46, then a first row of turns in the second secondary coil-receiving passage 48, then a second row of turns in the first secondary coil-receiving passage 46, then a second row of turns in the second secondary coil-receiving passage 48, and so on until the first and second secondary coil-receiving

passages

46, 48 are filled. It will be appreciated that other winding patterns are possible, and that the desired winding pattern may be selected to simplify manufacturing, if desired.

The assembled stator core assembly 10 may better align the coils 16 than, for example, an arrangement where there is a single channel on the back of the core of the stator core and extends across the entire width of the back of the core of the stator core. By dividing the coil 16 between the first and second secondary coil-receiving

channels

46, 48, each of the first and second

secondary channels

46, 48 may contain fewer turns of the coil 16 than arrangements using a single secondary channel, allowing for better alignment and tighter control of the coil 16 within the

respective channels

46, 48. Better alignment of the coils 16 may allow for greater consistency of the windings, such as during production of the stator assembly 10, which may result in better tolerances.

The stator core assembly 10 may be reduced in temperature during use relative to a bobbin having only a single secondary channel of the same width as its primary channel, as a greater surface area of the coil 16 may be exposed and thus may pass cooling airflow during use. The reduction in temperature can be further enhanced by ensuring that the first secondary coil-receiving passages 46 and the second secondary coil-receiving passages 48 extend over substantially the entire core back 22 of the stator core 10, as shown in fig. 9 to 11.

A permanent magnet machine 100 comprising four stator core assemblies 10 can be seen in fig. 12. Permanent magnet motor 100 is a single-phase brushless permanent magnet motor that includes a frame 102, a rotor assembly 104, and a diffuser 106. For clarity, the control circuitry of the motor 100 is not shown here.

The frame 102 has four slots 107, each slot receiving a corresponding stator assembly 10. The rotor assembly 104 includes first and

second bearings

108, 110, an eight-pole permanent magnet 112, a shaft 114, and an impeller 116. The

bearings

108, 110 are attached to a shaft 114 on either side of an octopole permanent magnet 112, and an impeller 116 is attached to one end of the shaft. The rotor assembly 104 is retained within the frame 102 by gluing the

bearings

108, 110 to corresponding bearing seats of the frame 102. The stator assembly 10 is positioned in the slot 107 using their respective first and

second positioning tabs

24, 26 before being glued in place so that the

pole arms

18, 20 face the octupole permanent magnet 112.

Figure 13 shows a vacuum cleaner 200 comprising a permanent magnet motor 100.

A method 300 of manufacturing the stator core assembly 10 will be described with reference to fig. 14.

The method 300 includes providing a stator core 12 having a first pole arm 18 and a second pole arm 20 connected by a core back 22 and a bobbin 14 having a primary coil receiving channel 42, a first secondary coil receiving channel 46, and a second secondary coil receiving channel 48 at 302. The method 300 includes mounting the stator core 12 to the bobbin 14 at 304 such that the primary coil-receiving channel 42 is located between the first and

second pole arms

18, 20 of the stator core 12 and the first and second secondary coil-receiving

channels

46, 48 are located on the core back 22 of the stator core 12. The method 300 includes winding the coil 16 around the bobbin 14 at 306 such that at least a portion of the coil 16 extends between the primary coil receiving channel 42 and the first secondary coil receiving channel 46 and at least a portion of the coil 16 extends between the primary coil receiving channel 42 and the second secondary coil receiving channel 48.

It will be appreciated that the stator core 12 and the bobbin 14 may be provided as a subassembly, and in such cases, the step 304 of mounting the stator core 12 to the bobbin 14 may be omitted.

The winding of the coil 16 at 306 may be performed in the manner previously discussed above.

For example, the coil 16 is wound around the bobbin 14 at 306 such that the first secondary coil-receiving passage 46 is filled first and then the second secondary coil-receiving passage 48 is refilled. Alternatively, the coil 16 is wound around the bobbin 14 at 306 such that a first row of turns is formed in the first secondary coil-receiving passage 46, then a first row of turns is formed in the second secondary coil-receiving passage 48, then a second row of turns is formed in the first secondary coil-receiving passage 46, then a second row of turns is formed in the second secondary coil-receiving passage 48, and so on until the first and second secondary coil-receiving

passages

Claims

1. A stator core assembly for a permanent magnet electric machine, the stator core assembly comprising a stator core; a bobbin to which the stator core is mounted; and a coil wound around the bobbin, wherein a first side of the bobbin comprises a primary channel, a second side of the bobbin comprises a first secondary channel and a second secondary channel, and the coil is wound around the bobbin such that at least a portion of the coil extends between the primary channel and the first secondary channel and at least a portion of the coil extends between the primary channel and the second secondary channel.

2. The stator core assembly of claim 1, wherein the stator core includes first and second pole arms and a core back connecting the first and second pole arms, the stator core mounted to a bobbin such that the primary channel is located between the first and second pole arms and the first and second secondary channels are located on the core back of the stator core.

3. The stator core assembly according to claim 1 or 2, wherein the bobbin comprises first and second end walls and an intermediate wall, the first and second end walls and the intermediate wall defining the first and/or second secondary channel.

4. The stator core assembly of any preceding claim, wherein each of the primary and secondary channels extends beyond the stator core.

5. The stator core assembly of any preceding claim, wherein the main channel comprises a single channel.

6. The stator core assembly of any preceding claim, wherein the first and second secondary channels extend over the entire second side of the bobbin.

7. The stator core assembly of any preceding claim, wherein the combined width of the first and second secondary channels is greater than the width of the main channel.

8. The stator core assembly of any preceding claim, wherein the first and second secondary passages comprise the same dimensions.

9. The stator core assembly according to any of the preceding claims, wherein the coil portion contained within the first secondary channel has the same dimensions as the coil portion contained within the second secondary channel.

10. A permanent magnet electric machine comprising a stator core assembly according to any preceding claim.

11. A vacuum cleaner comprising a permanent magnet motor according to claim 10.

12. A method of manufacturing a stator core assembly, the method comprising providing a stator core and a bobbin having a first side and a second side, the first side of the bobbin comprising a primary channel and the second side of the bobbin comprising a first secondary channel and a second secondary channel, the stator core being mounted to the bobbin; and winding a coil around the bobbin such that at least a portion of the coil extends between the primary channel and the first secondary channel and at least a portion of the coil extends between the primary channel and the second secondary channel.

13. The method of claim 12, wherein the method comprises alternately winding a coil between the primary channel and the first secondary channel and between the primary channel and the second secondary channel.

14. The method of claim 12, wherein the method comprises winding a coil between the primary tunnel and the first secondary tunnel until the first secondary tunnel is filled to a predetermined level, and then winding a coil between the primary tunnel and the second secondary tunnel until the second secondary tunnel is filled to a predetermined level.

15. The method of any one of claims 12 to 14, wherein the method comprises mounting the stator core to the bobbin such that the primary channel is located between first and second pole arms of the stator core and the first and second secondary channels are located on a core back of the stator core.