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Title:
SUCTION NOZZLE
Document Type and Number:
WIPO Patent Application WO/2019/008312
Kind Code:
A1
Abstract:
A suction nozzle for a vacuum cleaner comprises an agitator defining a longitudinal axis and being rotatable about said longitudinal axis; a motor configured to rotate the agitator; and a coolant path extending from an inlet to an outlet. The coolant path is configured to direct an air flow from the inlet, past the motor and subsequently over or through the motor, to the outlet.

Inventors:
STRUTT, Oliver (Dyson Technology Limited, Tetbury Hill, Malmesbury Wiltshire SN16 0RP, SN16 0RP, GB)
TWIST, Samuel (Dyson Technology Limited, Tetbury Hill, Malmesbury Wiltshire SN16 0RP, SN16 0RP, GB)
Application Number:
GB2018/051488
Publication Date:
January 10, 2019
Filing Date:
May 31, 2018
Export Citation:
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Assignee:
DYSON TECHNOLOGY LIMITED (Tetbury Hill, Malmesbury Wiltshire SN16 0RP, SN16 0RP, GB)
International Classes:
A47L9/02; A47L9/04; A47L9/28
Attorney, Agent or Firm:
WARNER, Thomas et al. (Intellectual Property Department, Dyson Technology Limited Tetbury Hill, Malmesbury Wiltshire SN16 0RP, SN16 0RP, GB)
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Claims:
CLAIMS

1 . A suction nozzle for a vacuum cleaner, the suction nozzle comprising:

an agitator defining a longitudinal axis and being rotatable about said longitudinal axis;

a motor configured to rotate the agitator; and

a coolant path extending from an inlet to an outlet,

wherein the coolant path is configured to direct an air flow from the inlet, past the motor and subsequently over or through the motor, to the outlet.

2. A suction nozzle according to claim 1 wherein the coolant path is configured to prevent said flow of air from contacting the agitator.

3. A suction nozzle according to claim 1 or 2 wherein the coolant path is configured to prevent the air flow from contacting the motor as the air flow is directed past the motor.

4. A suction nozzle according to any preceding claim wherein the motor is received at least partially inside the brush bar.

5. A suction nozzle according to claim 4 wherein the coolant path is configured to direct said air flow past the motor between the motor and the agitator.

6. A suction nozzle according to claim 5, incorporating claims 2 and 3, wherein:

the suction nozzle further comprises two generally concentric sleeves;

said sleeves are at least partially received inside the agitator;

the motor is at least partially received inside said sleeves; and

the coolant path is configured such that to said air flow runs in between said two sleeves past the motor, and runs inside said two sleeves over or through the motor.

7. A suction nozzle according to any preceding claim further comprises a gear assembly via which the motor can rotate the agitator, and the coolant path is further configured to direct said air flow over or through said gear assembly.

8. A suction nozzle according to claim 7 wherein:

the gear assembly is an epicyclic gear train comprising a sun gear, one or more planet gears mounted on a carrier, and a ring gear; and

the coolant path is configured to direct said air flow over the ring gear of the gear assembly.

9. A suction nozzle according to claim 7 or 8, wherein the coolant path is configured to direct the air flow over or through the gear assembly before directing the flow of air over or through the motor.

1 0. A suction nozzle according to any preceding claim wherein the coolant path is configured to direct said air flow into the agitator at an axial end of the agitator, and out of the agitator at the same axial end. 1 1 . A suction nozzle according to any preceding claim wherein the coolant path is configured to direct said air flow to run along at least 70% of the axial length of the agitator.

1 2. A suction nozzle according to any preceding claim wherein the inlet is configured such that air entering the inlet to form said air flow is taken from outside the suction nozzle.

1 3. A suction nozzle according to any preceding claim wherein the coolant path comprises a passage of annular cross section relative to the direction of movement of the air flow therethrough.

1 4. A suction nozzle according to any preceding claim wherein the agitator is removable from the suction nozzle.

1 5. A vacuum cleaner comprising a suction nozzle according to any preceding claim.

Description:
Suction Nozzle

The present invention relates to a suction nozzle of the type that can be used on a vacuum cleaner. The invention is not limited to suction nozzles for any particular type of vacuum cleaner. For example, it includes both cleaner heads on upright vacuum cleaners and floor tools on cylinder vacuum cleaners or handheld vacuum cleaners.

Some known vacuum cleaners comprise a rotating agitator such as a brush bar, which is driven to rotate by an electric motor. To reduce the risk of this motor overheating, some such vacuum cleaners include a coolant path through which an air flow is drawn. The air flow absorbs heat from the motor so as to cool it. However, in some cases other components (for instance gears through which the motor drives the agitator) can also be prone to overheating. The coolant paths of existing vacuum cleaners can fail to cool these components sufficiently if at all, and/or can cool these components but at the expense of adequate cooling of the motor. Furthermore, in some cases the air flow only absorbs heat from the motor for a relatively short time, limiting the amount of heat absorbed and thus leaving the motor at risk of overheating. It is an object of the invention to mitigate or obviate the above disadvantages, and or to provide an improved or alternative suction nozzle or vacuum cleaner.

According to a first aspect of the present invention there is provided a suction nozzle for a vacuum cleaner, the suction nozzle comprising:

an agitator defining a longitudinal axis and being rotatable about said longitudinal axis;

a motor configured to rotate the agitator; and

a coolant path extending from an inlet to an outlet,

wherein the coolant path is configured to direct an air flow from the inlet, past the motor and subsequently over or through the motor, to the outlet. This can allow the air flow †o cool another component of the suction nozzle, while nonetheless cooling the motor adequately. As an example, the coolant path may position the air flow adjacent to the agitator before, during and/or after it runs past the motor. The air flow can therefore cool the agitator, and then subsequently run over or through the motor and thereby cool the motor as well . In contrast, if the air flow ran over or through the motor and then ran adjacent to the agitator, the air flow would cool the agitator to a lesser extent (or may even heat the agitator) due to the air flow having been heated significantly by the motor. If the air flow ran past the motor and adjacent to the agitator but did not then flow over or through the motor, the motor may not be cooled sufficiently and may therefore overheat.

Instead or as well, the air flow running both past the motor and then over or through the motor may increase the time during which the air flow is exposed to heat from the motor, thereby increasing the cooling effect provided to the motor by the air flow. For instance, in the above example the air flow may absorb a first quantity of heat from the motor when running past it, and absorb a second quantity of heat from the motor when subsequently flowing over or through it. If instead the air flow only ran over or through the motor, the first quantity of heat would remain in the motor and potentially contribute to overheating.

The air flow is preferably directed through the motor, rather than over it, after being directed past the motor. This can increase the total amount of heat which can be absorbed by the airflow, and/or can allow components of the motor which get particularly hot (such as commutator brushes) or are particularly vulnerable to overheating (such as the insulation between coils) to be cooled more effectively. Nonetheless, in some embodiments sufficient heat may be removed from the motor by the air flow running over it.

Reference to the air flow being directed 'past' the motor is intended to mean that the air flow is directed to traverse the outside of the motor, whether or not the air comes into contact with the motor. Reference to the air flow being directed 'over' the motor is intended to mean that the air flow is directed to traverse the outside of the motor while in contact therewith. Reference to the air flow being directed through the motor is intended to mean that the air flow is directed to traverse the inside of the motor.

The coolant path may be configured such that the air flow can absorb heat from the motor while being directed past the motor. Alternatively, the coolant path may space the air flow apart from the motor (while directing the air flow past the motor) so that the air flow absorbs negligible heat from the motor while being directed past it.

The coolant path may be configured to prevent said flow of air from contacting the agitator.

This can avoid the need for a dynamic seal (which can be relatively complex and expensive to produce) to be provided so as to prevent the air flow from leaking out of the coolant path. The coolant path may be configured to prevent the air flow from contacting the motor as the air flow is directed past the motor.

The air flow not contacting the motor as it is directed past the motor can reduce the amount of heat the air flow collects from the motor as it passes the motor. The air flow may therefore be cooler during and after passing the motor, enabling the air flow to provide enhanced cooling to another component of the suction nozzle.

The motor may be received at least partially inside the agitator. For example, at least 50% or at least 75% of the total axial length of the motor may be positioned inside the agitator. Preferably, the motor is received entirely inside the brush bar.

The motor being received at least partially inside the brush bar may provide an advantageously compact arrangement, in comparison to an arrangement where the agitator and motor are housed separately. In an arrangement with the motor at least partially received within the agitator, les space may be provided around the motor. The problem of the motor overheating can therefore be more acute, and therefore applying the present invention to such an arrangement may be particularly beneficial.

The coolant path may be configured to direct said air flow past the motor between the motor and the agitator.

This may allow the air flow to cool the agitator as it passes the motor. Conventionally, the agitator is not particularly vulnerable to heat, however the agitator is often positioned in a manner that allows it to be touched by a user. It may therefore be advantageous in terms of safety for the agitator to be cooled in this manner.

Optionally:

the suction nozzle further comprises two generally concentric sleeves;

said sleeves are at least partially received inside the agitator;

the motor is at least partially received inside said sleeves; and

the coolant path is configured such that to said air flow runs in between said two sleeves past the motor, and runs inside said two sleeves over or through the motor.

The concentric sleeves may be an advantageously simple way of preventing the air flow from contacting the agitator and from contacting the motor while running past it, while allowing the air flow to run over or through the motor.

The suction nozzle may further comprise a gear assembly via which the motor can rotate the agitator, and the coolant path may further be configured to direct said air flow over or through said gear assembly.

The gear assembly may undergo significant heating due to friction between the meshing gears therein. It may therefore be particularly beneficial for the air flow to be directed over or through the gear assembly so that the gear assembly can be cooled. Where the air flow is directed through the gear assembly rather than over it, this may provide particularly intensive cooling of the gear assembly. However, where the air flow is directed over the gear assembly rather than through it, this may beneficially reduce the chances of the air flow picking up wear particles from the gear assembly and depositing them on the motor (which may damage the motor) .

Optionally:

the gear assembly is an epicyclic gear train comprising a sun gear, one or more planet gears mounted on a carrier, and a ring gear; and

the coolant path is configured to direct said air flow over the ring gear of the gear assembly.

The air flow being directed over the ring gear may offer the best compromise between maximising the cooling of the gear assembly and minimising the risk of the air flow picking up wear particles - the air flow contacts one of the gears of the gear assembly and may therefore provide good cooling, but does not flow inside the ring gear (where wear particles may accumulate) .

The coolant path may be configured to direct the air flow over or through the gear assembly before directing the flow of air over or through the motor.

The air flow passing over or through the gear assembly before passing over or through the motor may allow both components to be cooled satisfactorily. In contrast, if the air flow passed over or through the motor before passing over or through the gear assembly, the gear assembly may be inadequately cooled (or even heated) due to the air flow being too hot from the motor.

The coolant path may be configured to direct said air flow into the agitator at an axial end of the agitator, and out of the agitator at the same axial end. The air flow entering and exiting the agitator at the same axial end can reduce the number of design constraints placed on the other axial end of the agitator. For instance, the opposite axial end of the agitator can be engaged by the motor (or a component drivably connected thereto) and/or rotatably supported by a housing of the suction nozzle, without any complications being caused by the need to also accommodate a part of the coolant path. The coolant path may be configured to direct said air flow to run along at least 50% of the axial length of the agitator. For instance, the coolant path may be configured to direct said air flow to run along at least 60% or at least 70% of the axial length of the agitator.

This can increase the proportion of the agitator which can be cooled by the air flow, and/or increase the amount of time the air flow spends in proximity to the agitator and able to receive heat therefrom.

The inlet may be configured such that air entering the inlet to form said air flow is taken from outside the suction nozzle.

This may mean that the air flow is cleaner, in comparison to an arrangement where the air enters the inlet from inside the suction nozzle, where dirt may be entrained therein . That dirt may then clog the coolant path and/or build up on a component such as the motor and affect its performance.

The inlet is preferably positioned in an upper region of the suction nozzle. This may reduce the possibility that dirt resting on a surface being treated becomes entrained in the air entering the inlet, in comparison to an arrangement where the inlet is positioned at a lower region.

The agitator may be a brush bar configured for agitating the fibres of a carpeted surface so as to release dirt therefrom. As one alternative, the agitator may be a polishing buffer. As another alternative, the agitator may be a rotating mop. The coolant path may comprise a passage of annular cross section relative to the direction of movement of the air flow therethrough. This may allow the cooling effect of the air flow through the coolant path to be more evenly distributed.

The annular section may be positioned circumferentially around the longitudinal axis of the agitator, and/or circumferentially around part of the motor (and/or part of the gear assembly, where present).

The passage of annular cross section may be a single annular passage, or an annular array of discrete flow passages.

Where the suction nozzle comprises generally concentric sleeves as discussed above, the passage of annular cross section may be provided between the two sleeves.

The motor may be mounted to one end of the suction nozzle, and engage the agitator at an opposite end of the suction nozzle.

The agitator may be removable from the suction nozzle.

This can enable the agitator to be cleaner or serviced more easily (for instance to remove hair that has wrapped around it), and allows a user to replace a worn out or damaged agitator without having to replace the entire suction nozzle.

The agitator is preferably removable through an aperture at an axial end thereof. The suction nozzle may have an end cap for selectively closing the aperture.

The agitator may be removable from the suction nozzle along with the end cap, but may nonetheless be separable from the end cap.

According to a second aspect of the present invention there is provided a vacuum cleaner comprising a suction nozzle according to the first aspect of the invention. This may provide vacuum cleaner which provides one or more of the advantages discussed above.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a vacuum cleaner according to an embodiment of the invention;

Figure 2 is a perspective view of a cleaner head of the vacuum cleaner of Figure 1 ;

Figure 3 is a perspective view of the cleaner head of Figure 2, from underneath;

Figure 4 is a cut-away view of the cleaner head of Figures 2 and 3, viewed generally from the front;

Figure 5 is a cut-away view of the cleaner head, viewed generally from the top;

Figure 6 is a cross sectional view of the cleaner head, taken through a gear assembly thereof;

Figure 7 is a cross sectional view of the cleaner head, taken through a motor thereof;

Figure 8 is a cross sectional view of the cleaner head, taken through a motor support thereof;

Figure 9 is a perspective view of the cleaner head, with a top housing, agitator, inner sleeve and outer sleeve removed;

Figure 1 0 is perspective view of the assembly shown in Figure 9, with the inner sleeve in place; Figure 1 1 is a perspective view of the assembly shown in Figure 1 0, with the outer sleeve in place;

Figure 1 2 is a perspective view of the cleaner head, with an end cap detached therefrom; and

Figure 1 3 is a further perspective view of the cleaner head with the end cap detached therefrom.

Throughout the description and drawings, corresponding reference numerals denote corresponding features.

Figure 1 shows a vacuum cleaner 2 according to an embodiment of the invention. The vacuum cleaner 2 of this embodiment is an upright vacuum cleaner. It has a rolling assembly 4 which carries a suction nozzle 6 in the form of a cleaner head, and an 'upright' body 8. The upright body 8 can be reclined relative to the suction nozzle 6, and includes a handle 1 0 for manoeuvring the vacuum cleaner 2 across the floor. In use, a user grasps the handle 1 0 and reclines the upright body 8 until the handle 1 0 is disposed at a convenient height. The user can then roll the vacuum cleaner 2 across the floor using the handle 1 0 in order to pass the suction nozzle 6 over the floor and pick up dust and debris therefrom. The dust and debris is drawn into the suction nozzle 6 by a suction generator in the form of a motor-driven fan (not visible) housed on board the vacuum cleaner 2, and is ducted in conventional manner under the fan-generated suction pressure from an outlet duct 1 2 of the suction nozzle 6 to a cyclonic separating apparatus 1 4 where dirt is separated from the air. The relatively clean air is then exhausted back to the atmosphere.

The suction nozzle 6 is shown in isolation in Figures 2 and 3. It has a housing 1 6 made up of an upper housing 1 6a, lower housing 1 6b, front housing 1 6c, rear housing 1 6d and two end walls 1 6e, 1 6f. The upper and lower housings 1 6a, 1 6b and the end walls 1 6e, 1 6f of the housing 1 6 co-operatively define a suction chamber 1 8 which is in fluid communication with the outlet duct 1 2. The lower housing 1 6b and end walls 1 6e, 1 6f of the housing 1 6 co-operatively define a sole plate 20 which has a set of wheels 21 and a suction opening 22. An agitator 24 in form of brush bar is positioned inside the suction chamber 1 8. The brush bar 24 defines a longitudinal axis 26 is rotatable about its longitudinal axis within the suction chamber 1 8. The agitator 24 comprises two generally helical arrays of bristles (not shown), each of which is received by and projects from a generally helical groove 27 in the agitator.

The suction nozzle has a pair of large debris slots 28 in the sole plate 20, and a pair of bleeds 30 which run through the front housing. The large debris slots 28 and bleeds 30 can be opened and closed by a slidable switch 32 provided on the front housing 1 6c, but the function and structure of these components is not material to the present invention and therefore will not be described in detail .

In use, a user passes the suction nozzle 6 across a surface to be cleaned. The sole plate 20 engages the surface and air is sucked into the suction chamber 1 8 through the suction opening 22. The air is then drawn out of the suction chamber 1 8 and into the rolling assembly 4 through the outlet duct 1 2. When the suction nozzle 6 is resting on a hard surface such as a laminate floor, the suction nozzle 6 is supported by the wheels 21 . However, when the suction nozzle 6 is resting on a carpeted surface, the wheels 21 sink into the pile of the carpet and the suction opening 22 is therefore positioned further down. This allows carpet fibres to protrude through the suction opening 22, whereupon they are disturbed by the rotating agitator 24 so as to loosen dirt and dust therefrom. The mechanism by which the agitator 24 is driven will now be described, with reference to Figures 4- 1 1 in combination with Figures 1 -3. The agitator 24 has a substantially tubular part 24a in which the grooves 27 are provided, and a closed end part 24b. A motor 34 for rotating the agitator 24 about its longitudinal axis 26 is positioned fully within the agitator, more particularly approximately centrally within the tubular part 24a. The motor 34 is of conventional design and therefore will not be described in detail. The motor 34 drives the agitator via a gear assembly 36 in the form of an epicyclic gear train which comprises a sun gear 38, three planet gears 40 mounted a carrier 42, and a ring gear 44. The ring gear 44 is fixedy mounted to a casing 46 of the motor 34 by a gear adaptor 48, and the sun gear 38 is fixedly mounted on an output shaft 50 of the motor 34. The carrier 42 is rotatably mounted on the output shaft 50 via a bearing 52, and is fixedly mounted to a drive dog 54. The drive dog 54 has an external array 56 of teeth which mesh with an internal array of complementary teeth provided on the agitator 24. Accordingly, when the motor 34 is energised, the output shaft 50 and thus the sun gear 38 rotates and the ring gear 44 remains stationary. The planet gears 40 orbit the sun gear 38 and therefore the carrier 42, and thus the drive dog 54 and agitator 24, rotate as well . The gear assembly 36 gears down the drive from the motor 34 so that the agitator 24 rotates at a lower speed, but under higher torque, than the output shaft 50 of the motor.

The gear adaptor 48 extends circumferentially around the motor and ring gear, and has a circumferentially-spaced set of arms 60 with gaps 62 thebetween. The gaps 62 extend radially inwards through the gear adaptor and terminate at positions axially aligned with breather holes 64 in the front of the casing 46 of the motor 34. An o-ring 66 is positioned between the gear adaptor 48 and the casing 46 of the motor 34. The axial end of the ring gear 44 opposite to the motor 34 is covered by an elastomeric cover 68. Like the gear adaptor 48, the cover 68 extends circumferentially around the ring gear 44. These features of the gear adaptor 48 and cover 68 are more clearly visible in Figures 4- 6 and 9.

The motor 34 is mounted to a motor support 72 via a motor adaptor 74 and a sealing member 76. The motor support 72 is attached to a mounting member 78 via a sealing member 80, and the mounting member 78 is attached to the end wall 1 6e of the housing 1 6 via a sealing member 82. Accordingly, the motor 34 is mounted to one end of the suction nozzle 6, and engages the agitator 24 (via the gear assembly 36 and drive dog 54) at the opposite end of the suction nozzle.

The motor adaptor 74 is generally cup-shaped, with its open end abutting the casing 46 of the motor 34 so that inside space 84 of the motor adaptor 74 is in communication with breather holes 86 in the rear of the casing 46 of the motor 34. The closed end of the motor adaptor 75 has an aperture 88 in communication with the inside space 84. The motor support 72 is generally cylindrical, and has a hollow interior which defines an inflow chamber 90, an outflow chamber 92 and a wiring chamber 94. Each of these chambers 90, 92, 94 is open at each axial end of the motor support 72. The motor support 72 also has a radial aperture 96 in fluid communication with the inflow chamber 90.

The mounting member 78 and sealing member 82 co-operatively define a generally L- shaped channel 98 with a generally radially-extending arm 1 00 and a generally longitudinally-extending arm 1 02. Arm 1 00 has an axially-facing aperture 1 01 therein. Arm 1 02 is positioned within a duct 1 04 defined in the lower housing 1 6b. The duct 1 04 runs generally axially and terminates at the outlet 1 2. The mounting member 78 and sealing member 82 also define an inlet chamber 1 06 which is separate to the L-shaped channel 98, and which is positioned in fluid communication with a vent 1 08 in end wall 1 6e. The mounting member 78 and sealing member 82 also define an aperture 1 1 0 in fluid communication with the inlet chamber 1 06.

The wiring chamber 94 of the motor support 72 is closed (in this case sealed) at one end by sealing member 76, and at its other end by sealing member 80. The wiring chamber 94 is therefore air-tight. Wiring 1 1 2 for transmitting power to the motor 34 runs through the wiring chamber 94, and through a ferrite toroid 1 1 4 for suppressing electrical noise that is also positioned inside the wiring chamber.

The inflow chamber 90 of the motor support 72 is sealed closed at one end by sealing member 76, but at its other end is sealed against the aperture 1 1 0 in the mounting member 78 and sealing member 82. The inflow chamber 90 is therefore in fluid communication with the inlet chamber 1 06.

One end of the outflow chamber 92 is sealed against the aperture 88 of the motor adaptor 74 by a duct 1 1 5 of the sealing member 76. The outflow chamber 92 is therefore in fluid communication with the inside space 84 of the motor adaptor 74. The other end of the outflow chamber 92 is sealed against the aperture 1 01 in the radial ly- extending arm 1 00 of the L-shaped channel 98 by sealing member 80. The outflow chamber 92 is therefore also in fluid communication with the duct 1 04 in the lower housing 1 6b.

The suction nozzle 6 also has an inner sleeve 1 1 6 and an outer sleeve 1 1 8 positioned generally concentrically with respect to one another. The sleeves 1 1 6, 1 1 8 are received inside the agitator 24, and the motor is received within the sleeves. The sleeves 1 1 6, 1 1 8 extend circumferentially around the motor 34 and gear assembly 36, and are concentrically positioned inside the tubular part 24a or the agitator 24. The inner sleeve 1 1 6 is supported on sealing member 76, an o-ring 1 20 positioned around the motor adaptor 74, an o-ring 1 22 positioned around the gear adaptor 48, and the elastomeric cover 68. The outer sleeve 1 1 8 is supported on a sealing member 1 24 mounted on the motor support 72, and an o-ring 1 26 positioned around the inner sleeve 1 1 6. The sleeves 1 1 6, define a generally annular gap 1 28 therebetween. As discussed in more detail later, the gap 1 28 forms a passage of annular cross section (relative to the direction of movement of the air flow therethrough) . This passage is positioned circumferentially around the agitator axis 26, and circumferentially around the motor 34 and the gear assembly 36.

The inner sleeve 1 1 6 has an inlet aperture 1 30 at one end, a circumferential array of outlet apertures 1 32 at the other end, and a circumferential array of longitudinal ridges 1 34. The inner sleeve 1 1 6 also provides additional support for the carrier 42 via a bearing 1 35. The ridges 1 34 project radially outwards towards the outer sleeve 1 1 8, but are nonetheless radially spaced therefrom . The inlet aperture 1 30 of the inner sleeve 1 1 6 is positioned in alignment with the aperture 96 in the inflow chamber 90 of the motor support 72. Accordingly, the gap 1 28 between the sleeves 1 1 6, 1 1 8 is in fluid communication with the inflow chamber 90. Each outlet aperture 1 32 is positioned in alignment one of the gaps 62 in the gear adaptor 48, therefore the gap 1 28 is also in fluid communication with the breather holes 64 in the front of the casing 46 of the motor 34. The suction nozzle 6 defines a coolant path configured to direct an air flow from an inlet, past the motor and subsequently over or through the motor, to an outlet. In this case, the vent 108 in the end wall 16e forms the inlet of the coolant path, the duct 104 in the lower housing 16b forms the outlet, and the coolant path directs the air flow past the motor and subsequently through the motor. The coolant path runs through the vent 108, into the inflow chamber 109 through the inlet chamber 106, and into the gap 128 between the sleeves 116, 118. The air flow is then directed past the motor, axial ly along the gap 128 between the sleeves. The air then flows out of the gap 128, over the gear assembly 36 and through the motor 34 inside of the sleeves 116, 188. It then flows into the outflow chamber 92, through the L-shaped channel 98 and duct 104, and exits the suction nozzle 6 through the outlet 12. This will be described in more detail below.

When the vacuum cleaner 2 is in use, the suction generator reduces the pressure at the outlet 12. This, in turn, reduces the pressure inside the suction chamber 18 so as to draw air into it through the suction opening 22. Since the duct 104 is in fluid communication with the outlet 12, the pressure in the duct is also reduced. This acts to draw an air flow (in this case a separate air flow to the dirt-entraining air entering the suction chamber 18 through the suction opening 22) through the coolant path. The air flow enters the coolant path through the vent 108 and into the inlet chamber 106 that is defined by the mounting member 78 and sealing member 83. The vent 108 is positioned on an external surface of the suction nozzle 6, and therefore the air flow is taken from the relatively clean air outside the suction nozzle. In contrast, if the air flow was taken from the suction chamber 18 then dirt entrained therein would be passed through the coolant path, potentially clogging the coolant path and/or damaging the motor. The vent 108 is also positioned at an upper region of the suction nozzle 6 so as to space it apart from the surface being cleaned and thereby reduce the chances of the air flow entering the vent 108 entraining dirt resting on the surface.

From the inlet chamber 106, the air flow is drawn into the inflow chamber 90 through the aperture 110, and then into the gap 128 through the radial aperture 96 of the motor support 72 and the inlet aperture 130 in the inner sleeve 116. The air flow is prevented from leaking out of the coolant path between the inner sleeve 116 and motor adaptor 74 by the sealing member 76 engaging the inner sleeve. In some situations some of the air flow may leak out between the inner sleeve 1 1 6 and the motor support 72, however any such air would nonetheless be directed into the gap 1 28 by sealing member 1 24.

Upon entering the gap 1 28 through the inlet aperture 1 30 of the inner sleeve 1 1 6, the air can flow circumferentially around the gap, between the ridges 1 34 and the outer sleeve 1 1 8. The air flow then flows axially along the gap 1 28, between the motor 34 and the agitator 24, past the motor while circumferentially distributed around it. As the air flow passes the motor 34, it absorbs some heat therefrom and therefore has a cooling effect on the motor. The air flow also absorbs heat from the agitator 24 as the air flows along the gap 1 28 (and to a lesser extent as the air flows along the inflow chamber 90), ensuring that the agitator remains cool enough to be touched by the user.

When the air flow running axially along the gap 1 28 reaches the outlet apertures 1 32, it has run along around 70% of the total axial length of the agitator 24 (around 20% of the length of the agitator in the inflow chamber 90, and around 50% if the length of the agitator in the gap 1 28) . This relatively large proportion means that the cooling influence of the air flow is experienced by a larger proportion of the agitator 24. This is particularly true for the proportion of the axial length of the agitator 24 along which the air passes whilst in the gap 1 28, since the air flow is positioned closer to the agitator while in the gap.

Once the air flow has reached the outlet apertures 1 32 of the inner sleeve 1 1 6, the air flow runs over the parts of the ring gear 44 that are left exposed by the cover 68 and the arms 60 of the gear adaptor 48, and into the gaps 62 of the gear adaptor. As the air flow passes over the ring gear 44, it absorbs heat therefrom and therefore cools the ring gear 44 (and thus the gear assembly 36 as a whole) . Air is prevented from leaking out of the coolant path past the outlet apertures 1 32 in between the sleeves 1 1 6, 1 1 8 by o-ring 1 26, and is prevented from leaking out between the inner sleeve 1 1 6 and the gear adaptor 48 by o-ring 1 22. Further, air is prevented from leaking out of the coolant path and into the gear assembly 36 between the ring gear 44 and the motor casing 46 by o- ring 66, and is prevented from leaking out between the inner sleeve 1 1 6 and ring gear 44 by sealing engagement between the ring gear, elastomeric cover 68 and inner sleeve 1 1 6.

Since the air flow runs past the motor 34 between the sleeves 1 1 6, 1 1 8, as the air flow is directed past the motor it is prevented from contacting the motor. The inner sleeve 1 1 6 spaces the air flow apart from the motor 34, therefore the air flow does not absorb as much heat from the motor at this point as it would do if the inner sleeve was absent and the air flow could run over the motor. The air flow is therefore cooler when it reaches the gear assembly 36, and is thus more able to cool it. That being said, the inner sleeve 1 1 6 conducts heat away from the motor 34 and a significant proportion of this heat is absorbed by the air flow, therefore the air flow nonetheless has a cooling effect on the motor 34 as it is directed past it.

The outer sleeve 1 1 8 (along with the inflow and outflow chambers 90, 92 of the motor support 72) is positioned to as to prevent the air flow from contacting the agitator. I n contrast, if the outer sleeve 1 1 8 was absent and tubular portion 24a of the agitator 24 formed a wall of the coolant flow path, it would be necessary to provide kinetic seals at each end of the tubular portion (e.g. one between the tubular portion 24a and the sealing member 76, and another between the tubular portion and the end of the inner sleeve 1 1 6 which supports the carrier 42) . Such kinetic seals are generally relatively expensive, require relatively tight tolerances and wear out relatively quickly.

From the gaps 62 in the gear adaptor 48, the air flow runs into the casing 46 of the motor 34 through the breather holes 64, through the motor, out of the motor through the holes 86 and into the inside space 84 of the motor adaptor 74. As the air flow passes through the motor 34, it absorbs further heat from the motor, thereby providing an additional cooling effect thereto.

From the inside space 84 of the motor adaptor 74, the air flow runs through the aperture 88 in the motor adaptor, through the duct 1 1 5 of the sealing member 76 and into the outflow chamber 92 of the motor support 72. Leakage of air out of the coolant path between the motor adaptor 74 and sealing member 76 is prevented by engagement between the sealing member 76 and the inner sleeve 1 1 6 and by the o-ring 1 20.

The air in the outflow chamber 92 is then drawn through the aperture 1 01 into radially- extending arm 1 00 of the L-shaped channel 98 defined by the mounting member 78 and sealing member 82. The air then flows along the L-shaped channel 98, into the duct 1 04 which forms the outlet from the coolant path. The air flow then merges with dirt-entrained air flowing from the suction chamber 1 8, and exits the suction nozzle 6 through the outlet 1 2. It is noteworthy that in this embodiment the air flow through the coolant path flows over the gear assembly 36 and then through the motor 34. This ensures that the gear assembly is cooled sufficiently. If instead the air flow passed through the motor 34 and then over the gear assembly 36 (which may appear to be preferable at first glance, so as to avoid wear particles from the gear assembly from being drawn into the motor), the air flow may be too hot by the time it reaches the gear assembly for the gear assembly to be cooled adequately.

It is also to be noted that in this embodiment the coolant path directs the air flow to enter the agitator 24 at one axial end (through the aperture 1 1 0 and the inflow chamber 90), and to exit the agitator at the same axial end (through the outflow chamber 92 and the aperture 1 01 ) . This enables the opposite end of the agitator and the associated structure to be relatively simple in comparison to an arrangement where the coolant path was required to pass through this end of the agitator as well . In this embodiment, the agitator 24 is removable from the suction nozzle 6. More particularly, it is removable from around the motor 34. This will be described in more detail below with reference to Figures 1 2 and 1 3, in combination with Figures 1 - 1 1 . In this embodiment, the agitator 24 is removable through an aperture 1 36 in the casing 1 6 at an axial end of the agitator, which is selectively closable by an end cap 1 38. In this case, the end cap 1 38 provides end wall 1 6f, a sealing member 1 39, and a hair ingress flange 1 40 which projects into an end of the agitator in close radial clearance therewith so as to reduce the possibility of hair working its way further into the agitator 24.

The agitator is supported for its rotation on two bearings 1 42, 1 44. Bearing 1 42 is positioned in the hair ingress flange 1 40 of the end cap, and engages a stub 1 46 of the closed end part 24b of the agitator 24. Bearing 1 44 is positioned on the motor support 72, adjacent to another hair ingress flange 1 48, and engages the inside of the tubular part 24a of the agitator 24 via a support ring 1 50. The support ring 1 50 has a circumferential array of spaced-apart fins 1 52 which slidingly engage the tubular part 24a of the agitator. The fins 1 52 being spaced apart means that any pressure difference across the support ring 1 50 (for instance due to a temperature difference) can equalise. Otherwise, this pressure difference could pull dirt into the bearing 1 44 and clog it.

The end cap 1 38 has circumferential array of recesses 1 54, each recess being bounded by an outwardly-projecting ridge 1 56. The aperture 1 36 has a complementary circumferential array of projections in the form of lugs 1 58. The end cap 1 38 can be attached to the housing suction nozzle 6 by rotating the end cap about the longitudinal axis 26 of the agitator 24 to a locked position, which positions each lug 1 58 within a corresponding recess 1 54. In other words, the ridges 1 56 are 'hooked' onto the lugs 1 58. The end cap 1 38 can be released from the suction nozzle 6 by rotating the end cap 1 38 to the unlocked position, which positions the lugs 1 58 outside of the recesses 1 54.

The end cap 1 38 has a pivotable latch member 1 60 which can secure the end cap in the locked position. This reduces the risk of the end cap 1 38 being rotated to the unlocked position (thereby potentially opening the aperture 1 36 and releasing the agitator 24) unintentionally, for instance due to a knock. The latch member 1 60 is pivotably mounted on the end cap 1 38, and has a latch tooth (not visible) and a push-button 1 62. The latch tooth (not visible) engages an abutment surface 1 64 provided on the lower housing 1 6b so as to prevent rotation of the end cap 1 38 to the unlocked position . Further, the latch tooth (not visible) can be lifted out of alignment with the abutment surface by pressing the button 1 62 and thereby pivoting the latch member 1 60. The agitator 24 sildably engages the bearing 1 44 via the support ring 1 50 as noted above. However, the stub 1 46 of the agitator 24 and the bearing 1 42 exhibit an interference fit. Accordingly, when a user removes the end cap 1 38, the agitator is removed along with it. Nonetheless, the agitator 24 and end cap 1 38 are separable from one another by applying sufficient force to overcome the interference fit between the bearing 1 42 and the agitator 24.

It is noteworthy that in this embodiment the sealing members 76, 80, 82 and 1 24; o-rings 1 20, 1 22, 1 26; and cover 68 are all deformable, in this case being made of elastomeric material . This not only ensures that a full seal can be provided, but also the sealing members to provide additional functionality. These components being deformable means that slight misalignment between parts of the suction nozzle 6 can be accommodated without adversely affecting performance. Also, the deformability of these components can reduce the propagation of vibration between different parts of the suction nozzle, acting as dampers and thereby making the suction nozzle more stable and/or quieter.

It will be appreciated that numerous modifications to the above described embodiments may be made without departing from the scope of invention as defined in the appended claims. For instance, whilst in the above embodiment the air flow through the coolant path is directed past the motor and then through the motor, in other embodiments the air flow may be directed past the motor and then over the motor (for instance it may pass over the circumferential periphery of the casing of the motor) . Similarly, in other embodiments the air flow may run through the gear assembly rather than over it.

In the above embodiment, the gap between the inner and outer sleeves forms a passage of continuous annular cross section. I n other embodiments, however, the gap may form a passage of annular cross section which is made up of an annular array of individual passages (as would be the case, for instance, if the ridges of the inner sleeve of the embodiment above were extended so that they contacted the outer sleeve) . Other embodiments may utilise inner and outer sleeves, but the sleeves may not define a passage of annular cross section. For example, the outer surface of the inner sleeve may contact the inner surface of the outer sleeve around most of its circumference, and be spaced therefrom at a single circumferential point so as to define a single passage of non- annular cross section.