COMPRESSOR COMPRISING A FLOW GUIDE DISPOSED WITHIN AN AIR INLET

Abstract

A compressor has a stator assembly, a rotor assembly, and a housing within which the stator assembly and the rotor assembly are located. The housing has a first end, a second end, and an air inlet disposed between the first and second ends. The compressor has a flow guide disposed within the air inlet. The flow guide is configured to split air flowing through the air inlet in use into a first airflow toward the first end of the housing and a second airflow toward the second end of the housing.

Claims

1. A compressor comprising a stator assembly, a rotor assembly, and a housing within which the stator assembly and the rotor assembly are located, wherein the housing comprises a first end, a second end, and an air inlet disposed between the first and second ends, the compressor comprises a flow guide disposed within the air inlet, and the flow guide is configured to split air flowing through the air inlet in use into a first airflow toward the first end of the housing and a second airflow toward the second end of the housing.

2. The compressor as claimed in claim 1, wherein the air inlet is spaced apart from the first and second ends of the housing.

3. The compressor as claimed in claim 1, wherein the first end of the housing is closed.

4. The compressor as claimed in claim 3, wherein the first end of the housing is closed by control circuitry of the compressor.

5. The compressor as claimed in claim 1, wherein the rotor assembly comprises at least one magnet which is disposed within the first end of the housing.

6. The compressor as claimed in claim 6, wherein the at least one magnet is disposed within the first end of the housing such that the at least one magnet is at least partially misaligned with the air inlet.

7. The compressor as claimed in claim 1, wherein the housing is substantially cylindrical in global form, and the air inlet is located on a curved surface of the housing.

8. The compressor as claimed in claim 1, wherein the flow guide and the housing comprise separate components attached to one another by fixing means.

9. The compressor as claimed in claim 8, wherein the fixing means comprise at least one clip formed on the flow guide and/or the housing.

10. The compressor as claimed in claim 8, wherein the air inlet comprises a window formed in the housing, the window having at least two opposing edges, and the flow guide comprises at least two clips that are engagable with the at least two opposing edges to locate the flow guide within the air inlet.

11. The compressor as claimed in claim 10, wherein the flow guide comprises a guide surface, and the guide surface is obliquely angled relative to the at least two clips.

12. The compressor as claimed in claim 1, wherein the rotor assembly comprises a rotor magnet and at least one bearing, the rotor magnet and the at least one bearing being disposed in the housing at least partially between the air inlet and the second end of the housing.

13. The compressor as claimed in claim 1, wherein the rotor assembly comprise a first bearing located at the first end of the housing and a second bearing located at the second end of the housing.

14. The compressor as claimed in claim 1, wherein the stator assembly comprises at least one stator core, and at least one phase winding wound around the at least one stator core, the at least one stator core and the at least one phase winding being disposed in the housing at least partially between the air inlet and the second end of the housing.

15. The compressor as claimed in claim 1, wherein the housing comprises a plurality of air inlets and a single flow guide, with the single flow guide disposed within a single air inlet.

16. The compressor as claimed in claim 1, wherein the housing comprises a plurality of air inlets and a plurality of flow guides, each flow guide being disposed within a respective air inlet.

17. A vacuum cleaner comprising the compressor according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to better understand the present invention, and to show more clearly how the invention may be put into effect, the invention will now be described, by way of example, with reference to the following drawings:

[0037] FIG. 1 is a perspective view of a compressor according to the present invention;

[0038] FIG. 2 is an exploded perspective view of the compressor of FIG. 1;

[0039] FIG. 3 is a perspective view of a stator element of the compressor of FIG. 1 in isolation;

[0040] FIG. 4 is a perspective view of the rotor assembly of the compressor of FIG. 1 in isolation;

[0041] FIG. 5 is a perspective view of the frame of the compressor of FIG. 1 in isolation;

[0042] FIG. 6 is a perspective view of the housing of the compressor of FIG. 1 in isolation;

[0043] FIG. 7 is a perspective view of the flow guide of the compressor of FIG. 1 in isolation;

[0044] FIG. 8 is an enlarged view of the location of the flow guide in the compressor of FIG. 1;

[0045] FIG. 9 is a schematic cross-sectional view indicating airflow through the compressor of FIG. 1; and

[0046] FIG. 10 is a perspective view of a vacuum cleaner incorporating the compressor of FIG. 1.

DETAILED DESCRIPTION

[0047] A compressor according to the present invention, generally designated 10, is shown in FIGS. 1 to 2.

[0048] The compressor 10 comprises a stator assembly 12, a rotor assembly 14, a frame 16, a housing 18, a diffuser 20, and a flow guide 100.

[0049] The stator assembly 12 comprises four stator elements 22,24,26,28. Each stator element 22,24,26,28 comprises a stator core 30, a bobbin 32, and a winding 34, as shown in FIG. 3.

[0050] The rotor assembly 14 is shown in isolation in FIG. 4, and comprises a shaft 36 to which are mounted a rotor magnet 38, first 40 and second 42 balancing rings, first 44 and second 46 bearings, and an impeller 48.

[0051] The shaft 36 has first 50 and second 52 ends. The rotor magnet 38 is attached to the shaft 36 between the first 50 and second 52 ends, with the first 40 and second 42 balancing rings located on the shaft 36 either side of the rotor magnet 38. The first bearing 44 is attached to the shaft 36 toward the first end 50 of the shaft 36, and the second bearing 46 is attached to the shaft 36 toward the second end 52 of the shaft 36. The impeller 48 is attached to the shaft 36 at the second end 52 of the shaft 36.

[0052] The frame 16 is shown in isolation in FIG. 5, and comprises a main body 54 and a shroud 56. The main body 54 is generally cylindrical and hollow in form, and has first 58 and second 60 ends. The first end 58 of the main body 54 defines a first bearing seat 62 for receiving the first bearing 44, and the second end 60 of the main body 54 defines a second bearing seat 64 for receiving the second bearing 46. The rotor assembly 14 is held within the frame 16 by the engagement of outer races of the first 44 and second 46 bearings with the respective first 62 and second 64 bearing seats.

[0053] The first bearing seat 62 is dimensioned to also receive, with clearance, a sensor magnet 66 attached to the second end 52 of the shaft 36, such that the sensor magnet 66 is free to rotate with the shaft 32 in use. An external surface of the first bearing seat 62 has a pocket 68 formed therein, with the pocket 68 receiving a hall sensor (not shown). The sensor magnet 66 and the hall sensor interact in use to provide an indication of the position of the rotor magnet 38.

[0054] The main body 54 has four mounting apertures 72, with the mounting apertures 72 being spaced evenly about the circumference of the main body 54 between the first 58 and second 60 ends of the main body 54. The mounting apertures 72 each receive a corresponding stator element 22,24,26,28, with the stator elements 22,24,26,28 being mounted to the main body 54 such that a stator core 30 extends at least partially through each mounting aperture 72. The mounting apertures 72 are located on the main body 54 such that the stator cores 30 are generally aligned with the rotor magnet 38 when assembled.

[0055] The shroud 56 is generally frusto-conical and hollow in form, and is attached to the second end 60 of the main body 54 in the region of the second bearing seat 64 by four struts 74. The shroud 56 is located such that the shroud 56 covers the impeller 48.

[0056] The housing 18 is shown in isolation in FIG. 6, is generally cylindrical and hollow in form, and has first 76 and second 78 ends. The first end 76 of the housing 18 is generally open, and has four struts 80 that meet to define a mount 82 for the first bearing seat 62 of the frame 16. The periphery of the first end 76 of the housing 18 is shaped to define a circuit board mount 84 which receives a printed circuit board 86 that is used to control the compressor 10 in use. The printed circuit board 86 is attached to the circuit board mount 84 such that the open first end 76 of the housing 18 is sealed by the printed circuit board 86, and the lower surface of the printed circuit board 86 is in fluid communication with the interior of the housing 18.

[0057] The second end 78 of the housing 18 is generally open, and receives an upper lip 88 of the shroud 56. The housing 18 is attached to the frame 16 at the upper lip 88 of the shroud 56 and at the second bearing seat 64, such that an annular channel 90 (seen more clearly in FIG. 9) is defined between the frame 16 and the housing 18. A portion of each of the stator elements 22,24,26,28 is disposed in the annular channel 90.

[0058] The housing 18 has four air inlets 92 evenly spaced about the circumference of the curved surface of the housing 18. The four air inlets 92 are located between the first 76 and second 78 ends of the housing 18, and are closer to the first end 76 of the housing 18 than the second end 78 of the housing 18.

[0059] Each air inlet 92 is generally rectangular in form, such that each air inlet 92 has a first pair of opposing edges 94 and a second pair of opposing edges 96. The air inlets 92 are in fluid communication with the annular channel 90, such that a flow path through the compressor is defined by the air inlets 92, the annular channel 90, and an outlet 98 of the shroud 56 into the diffuser 20. Details of the diffuser 20 are not pertinent to the present invention and so will not be described here for the sake of brevity, save to say that the diffuser 20 is a three stage diffuser.

[0060] The flow guide 20 is shown in isolation in FIG. 7, and comprises lateral edges defining first 102 and second 104 clips, and a guide surface 106 located between the first 102 and second 104 clips. Each of the first 102 and second 104 clips has a mounting channel that co-operates with a respective one of the second pair of opposing edges 96 of an air inlet 92 to mount the flow guide 20 in said air inlet 92. The guide surface 106 is a slightly curved plane, and is obliquely angled relative to the first 102 and second 104 clips. The first 102 and second 104 clips extend axially past the guide surface 106 in one direction, whilst the guide surface 106 extends axially past the first 102 and second 104 clips in an opposing direction.

[0061] An enlarged view of the flow guide 100 located within the air inlet 92 is shown in FIG. 8. As can be seen, the flow guide 100 is located such that the guide surface 106 is angled toward the first end 76 of the housing 18. The flow guide 100 splits the air inlet 92 in which it is located into a first inlet aperture 108 and a second inlet aperture 110. The first inlet aperture 108 is defined by the generally planar portion of the guide surface 106 and a first edge 112 of the first pair of opposing edges 94 of the air inlet 92, whilst the second inlet aperture 110 is defined by a lower edge 114 of the guide surface 106 and a second edge 116 of the first pair of opposing edges 94 of the air inlet 92. In such a manner the first inlet aperture 108 is generally occluded by the guide surface 106, whilst the second inlet aperture 110 is generally free from occlusions.

[0062] In use, current is pushed into the phase windings 34 of the stator elements 22,24,26,28, such that a magnetic field is induced. The induced magnetic field interacts with the rotor magnet 38 to spin the shaft 36, and hence the impeller 48. The impeller 48 generates an airflow through the compressor 10.

[0063] The flow of air through the compressor 10 is indicated schematically in FIG. 9. Air generally enters the housing 18 via the air inlets 92, before flowing through the annular channel 90, past the impeller 48, through the outlet 98 of the shroud 56, and into the diffuser 20.

[0064] As mentioned above, the flow guide 100 is located in a given one of the air inlets 92 such that first 106 and second 108 inlet apertures are defined. For the given air inlet 92, the flow guide 100 splits air flowing through the air inlet 92 into a first airflow 118 and a second airflow 120. Due to the form of the guide surface 106, the first airflow 118 is directed toward the first end 76 of the housing 18, whilst the second airflow 120 is drawn toward the second end 78 of the housing 18 by the action of the impeller 48. It will of course be appreciated by a person skilled in the art that the first airflow 118 will turn and be drawn toward the second end 78 of the housing 18, once it has reached the first end 76 of the housing 18, under action of the impeller 48.

[0065] As discussed above, both the sensor magnet 66 and the first bearing 44 are located at the first end 76 of the housing 18. As the first airflow 118 is directed toward the first end 76 of the housing 18 by the flow guide 100, the first airflow 118 may pass over the sensor magnet 66 and the first bearing 44 in use. This may provide increased cooling of the sensor magnet 66 and the first bearing 44 relative to an arrangement where there is no flow guide, ie where airflow is not directed toward the first end 76 of the housing 18. Increased cooling of the sensor magnet 66 and the first bearing 44 may lead to improved lifetimes, and may enable the compressor to be run at a higher power, where more heat would typically be generated within the housing 18 in use.

[0066] Furthermore, as noted above the open first end 76 of the housing 18 is sealed by the printed circuit board 86, and the lower surface of the printed circuit board 86 is in fluid communication with the interior of the housing 18. As seen from FIG. 9 in particular, the lower surface of the printed circuit board 86 is in fluid communication with the first end 76 of the housing 18. Thus in use the first airflow 118 may be directed toward the lower surface of the printed circuit board 86, and the printed circuit board 86 may be provided with an increased level of cooling relative to an arrangement where there is no flow guide, ie where airflow is not directed toward the first end 76 of the housing 18.

[0067] Use of the flow guide 100 may further allow for increased flexibility in the choice of location of the air inlet 92, for example allowing for the air inlet 92 to be moved closer toward the second end 78 of the housing 18 whilst sill providing cooling airflow at the first end 76 of the housing 18.

[0068] Whilst not shown in the figures, embodiments are also envisaged where a flow guide 100 is located in each air inlet 92. Such an arrangement may result in greater airflow directed toward the first end 76 of the housing 18, but may result in a drop in pressure rise across the compressor 10, and particularly may result in a loss of airwatts where the compressor 10 is used in a vacuum cleaner 200 (such a vacuum cleaner is shown in FIG. 10, although the details are not pertinent to the present invention and will not be described here for the sake of brevity). There is therefore a compromise to be reached. Use of a single flow guide 100 may provide adequate cooling at the first end 76 of the housing 18 without a significant reduction in pressure rise, whilst the use of multiple flow guides may give increased cooling but also result in a larger reduction in pressure rise.