CN218062684U

CN218062684U - Pump assembly and cleaning equipment

Info

Publication number: CN218062684U
Application number: CN202123311245.0U
Authority: CN
Inventors: 史蒂文·布莱克; 韦恩·安德鲁·梅森; 泽维尔·桑德; 布鲁斯·桑德斯
Original assignee: Fischer Parker Home Appliances Co ltd
Current assignee: Fischer Parker Home Appliances Co ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-12-16
Anticipated expiration: 2031-12-27
Also published as: CN218062690U; CN217873314U

Abstract

The present invention relates to a pump and a washing device for a washing device, in particular a dishwasher. The utility model discloses an embodiment has improved the pump package spare, and the pump package spare includes: a drive shaft; a rotor coupled to the drive shaft and a discharge pump impeller mounted to the drive shaft; and a washing pump impeller installed at an upper end of the driving shaft. The improvement is that: the lower edge of the radial blade of the cleaning pump impeller is above the upper surface of the fluid inflow port; the lower bearing housing on the drive shaft has an annular seal configured to contact a surface of the housing when the pump assembly is inserted into the housing, and the lower bearing housing has a plurality of legs having ends configured to interlock with corresponding features of the upper bearing housing.

Description

Pump assembly and cleaning equipment

Technical Field

The utility model relates to a pump and cleaning equipment for cleaning equipment, cleaning equipment specifically are dish washer.

Background

Discharge pumps and wash pumps are used in washing devices such as dishwashers. Our currently available Dishdrawer, as disclosed for example in WO1993012706 and WO1998033426 ^TM The washing system of the drawer dishwasher comprises a washing pump located in the centre of the bottom of the washing tub. The cleaning pump sucks the cleaning liquid radially below the filter plate above a heating plate surrounding the cleaning pump. The heated cleaning solution then flows into the cleaning pump inlet and then upwardly through the impeller mounted within the spray arm. Soil or other particles that are too large to pass through the perforations in the coarse filter plate are flushed into the drain. WO2016130027 shows an alternative drawer dishwasher in which smaller filter plate inserts are used to reduce water usage. Similar purge and drain pump arrangements are used.

The entire washing system is designed such that the vertical height utilizes the over-limitation of a minium-drawer type dishwasher. Such pumps are usually mounted at the bottom of the washing chamber of the dishwasher, the pump water entering the washing chamber from a spray arm arranged above the pump. A certain level of water in the washing chamber is required to start the pump before it starts to operate.

A dishwasher drain pump is disclosed in us patent No. 8397736B 2. The pump includes a housing or shell that communicates with a sump in the floor of the wash chamber where wash water collects and enters the lower portion of the housing. The lower part of the housing provides an outer casing within which the discharge impeller operates to pump wash water from the sump into an outlet pipe connected to the pump.

The inventors have found that prior art pumps have performance inconsistent with pump priming which results in less efficient cleaning performance.

The inventors have also found that in some cases water can migrate from the lower portion of the housing to other areas of the pump housing where it can adversely affect cleaning efficiency.

Disclosure of Invention

It is an object of the present invention to provide a pump for a washing apparatus which in some way improves the above-mentioned pump, or which at least will provide the art with a useful choice.

According to an aspect of the present invention, the present invention resides broadly in a pump assembly for use with a spray arm in a cleaning chamber of a cleaning apparatus, the pump assembly comprising: a drive shaft; a rotor coupled to the drive shaft; a discharge pump impeller mounted to the drive shaft, the discharge pump impeller configured to pump water into the discharge; a wash pump impeller mounted on an upper end of the drive shaft, the wash pump impeller including a plurality of radial vanes extending along at least a portion of the drive shaft, the wash pump impeller configured to draw fluid from a fluid flow inlet and generate an upward axial outlet flow of fluid, wherein a lower edge of each of the plurality of radial vanes is above an upper surface of the fluid flow inlet.

Preferably, a spray arm bearing is also included, wherein the spray arm bearing is held in position relative to the pump assembly, a lower edge of the spray arm bearing forming an upper surface of the fluid flow inlet.

Preferably, an annular rotor chimney is also included which supports the spray arm bearings in place.

Preferably, the lower edge of the spray arm bearing is flush with the lower surface of the annular rotor chimney and forms the upper surface of the fluid flow inlet.

Alternatively, an annular rotor chimney portion is also included, wherein a lower surface of the annular rotor chimney portion forms an upper surface of the water flow inlet.

Preferably, the pump assembly is configured to be insertable into a pump housing in a base of the washing apparatus.

Preferably, a pump housing in the base of the washing machine houses a stator configured to engage with a rotor of the pump assembly to form a motor arrangement capable of rotating the drive shaft.

Preferably, the upper surface of the pump housing in the base of the washing apparatus is the lower surface of the water flow inlet.

Preferably, the washing pump further comprises an upper bearing housing containing the drive shaft, the upper bearing housing forming a floor below the washing pump impeller, wherein an upper surface of the upper bearing housing defines a flush surface with an upper surface of the pump housing.

Preferably, the clearance between the lower edge of each of the plurality of radial vanes and the surface of the upper bearing housing is less than or equal to 10mm.

Preferably, a spray arm is included that rotationally rests on the spray arm bearing, the spray arm including a circular opening in its base such that at least part of the wash pump impeller rests within a cavity in the spray arm.

Preferably, the distance between the lower edge of each of the plurality of radial vanes and the upper surface of the fluid flow inlet is between 1mm and 2mm.

Preferably, the purge pump impeller and the discharge pump impeller are mounted at opposite ends of the drive shaft.

According to another aspect of the present invention, the invention resides broadly in a cleaning apparatus including a pump assembly, wherein the cleaning apparatus is a drawer dishwasher, the cleaner chamber being slidably mounted in a cabinet.

According to another aspect, the invention may broadly be said to consist in a pump assembly for insertion into a housing in a base of a wash chamber of a washing apparatus, the pump assembly comprising: a rotor; a drive shaft coupled to the rotor; a wash pump impeller rotationally engaged with the drive shaft at or towards a top of the drive shaft; and a discharge pump impeller rotationally engaged with the drive shaft at or towards a bottom of the drive shaft; and a lower bearing housing on the drive shaft between the purge pump impeller and the discharge pump impeller to prevent axial fluid flow, wherein the lower bearing housing includes an annular seal configured to contact a surface of the housing when the pump assembly is inserted within the housing.

Preferably, the lower bearing housing includes an annular lip configured to contact a flange of the housing when the pump assembly is inserted into the housing, wherein the annular seal is below the annular lip.

Preferably, the annular seal is overmolded to the lower bearing housing.

Preferably, the annular seal comprises an annular portion and a lip, the lip being configured to contact the housing when the pump assembly is inserted into the housing.

Preferably, the lip has a horizontal upper surface and a sloping lower surface which intersects the annular portion of the seal.

Preferably, the lower bearing housing comprises an annular recess configured to receive the annular seal.

Preferably, the lower bearing housing includes a plurality of legs extending upwardly toward the washer pump impeller.

Preferably, an upper bearing housing is also included on the drive shaft between the washer pump impeller and the lower bearing housing, wherein each leg includes an end configured to interlock with a corresponding feature of the upper bearing housing to prevent axial movement of the lower bearing housing relative to the upper bearing housing.

Preferably, the rotor is located between the upper bearing housing and the lower bearing housing.

Preferably, each end comprises a flat surface and an inclined surface, wherein the flat surface is orthogonal to the drive shaft.

Preferably, the plurality of legs are biased outwardly, wherein, when inserted, the plurality of legs contact the housing and are urged inwardly to fit against the upper bearing housing.

According to another aspect, the present invention may broadly be said to consist in a motor assembly for a cleaning apparatus, the motor assembly comprising: a stator assembly configured to receive a stator and including a lower portion and an upper portion forming a central opening, the upper and lower portions being connected at an interface, the upper portion having a flange; and a pump assembly as set forth in the other aspects, wherein the annular seal is above an interface of the upper and lower portions of the housing.

Preferably, the stator housing includes a plurality of axial channels on a surface of the central opening and the lower bearing housing includes a plurality of legs, wherein the plurality of legs are located within the plurality of axial channels when the pump assembly is inserted into the stator assembly.

Preferably, the pump assembly is insertable into and removable from the central opening of the stator assembly.

According to another aspect, the invention may broadly be said to consist in a pump assembly for insertion into a housing in a base of a wash chamber of a washing apparatus, the pump assembly comprising: a rotor; a drive shaft coupled to the rotor; a wash pump impeller rotationally engaged with the drive shaft at or towards a top of the drive shaft; and a discharge pump impeller rotationally engaged with the drive shaft at or towards a bottom of the drive shaft; an upper bearing housing on the drive shaft between the purge pump impeller and the lower bearing housing on the drive shaft, the lower bearing housing on the drive shaft between the purge pump impeller and the discharge pump impeller to prevent axial fluid flow, the lower bearing housing including a plurality of legs extending upwardly toward the purge pump impeller, each of the plurality of legs having an end, and wherein each end is configured to interlock with a corresponding feature of the upper bearing housing to prevent axial movement of the lower bearing housing relative to the upper bearing housing.

Preferably, the end portion includes a flat surface and an inclined surface orthogonal to the drive shaft.

Preferably, the rotor is located between the upper and lower bearing housings.

Preferably, the plurality of legs are biased outwardly, wherein when inserted, the plurality of legs contact the housing and are pushed inwardly such that each end interlocks with the upper bearing housing.

Preferably, the lower bearing housing comprises an annular seal configured to contact a surface of the housing when the pump assembly is inserted into the housing.

Preferably, the base of each of the plurality of legs has a depth of between 2.5mm and 3.5mm and a width of between 3mm and 4 mm.

According to another aspect, the present invention may broadly be said to consist in a motor assembly for a cleaning apparatus, the motor assembly comprising: a stator assembly configured to receive a stator and including a lower portion and an upper portion forming a central opening, the upper and lower portions being connected at an interface, the upper portion having a flange; the pump assembly of the preceding aspect, wherein the stator housing includes a plurality of axial channels on a surface of the central opening, wherein the plurality of legs are located within the plurality of axial channels when the pump assembly is inserted into the stator assembly.

Preferably, the plurality of channels are arranged in the space between the stator windings in the stator assembly.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth in the figures.

The term "comprising" as used in this specification means "consisting at least in part of … …". When interpreting each statement in this specification that includes the term "comprising," features other than that term or those preceding that term can also be present. Related terms such as "comprise" and "comprises" should be interpreted in the same way.

Drawings

Figure 1 shows a schematic view of a dishwashing appliance including a pump of the present invention.

Figure 2 is a view of a connected stator assembly and pump assembly.

FIG. 3 is a cross-sectional view of an embodiment of the pump assembly and stator assembly of FIG. 2.

FIG. 4 is a view of a pump assembly.

FIG. 5 is a cross-sectional view of an embodiment of the pump assembly and stator assembly of FIG. 4.

FIG. 6A is a partial cross-sectional view of a lower bearing housing of the pump assembly.

FIG. 6B is a view of the lower bearing housing of the pump assembly.

Fig. 7A is a partial cross-sectional view of an embodiment of a pump assembly and a stator assembly showing a lower bearing housing.

FIG. 7B is an enlarged cross-sectional view of the leg of the lower bearing housing where the leg meets the upper bearing housing.

FIG. 8 is a horizontal cross-sectional view of the pump assembly of FIG. 4 showing the lower bearing housing legs and stator.

Detailed Description

A cleaning apparatus 100 comprising the pump of the present invention is of the type shown in figure 1. The cleaning apparatus 100 includes a cleaning tank 101 (including all cleaning system components), the cleaning tank 101 having a base 102 and one continuous sidewall or separate connected sidewalls that surround or enclose a cleaning chamber or cleaning volume 104. The washing tub 101 is fitted with a front panel 105 having a handle (not shown) and is slidably mounted in a drawer-type arrangement within the cabinet 106. The wash chamber 104 has an open top and is withdrawn from the cabinet in the direction of the arrow to allow, for example, loading and unloading of the trays while washing takes place and retracted into the cabinet 106. The washing system is mounted within the washing tub 101 and may include a drain pump 108, a wash pump 107 and a heating arrangement 109, the drain pump 108, wash pump 107 and heating arrangement 109 each being located substantially in the lower part of the washing tub, below the upper surface 114 of the base 102 of the washing tub (the surface 114 forming at least part of the floor of the washing chamber or washing space 104). The washing tub also has a filter pad and a filter 110.

A rotatable spray arm 115 is also provided in the wash tank 101, generally in the lower portion of the wash space 104, above the base upper surface 114. As is well known, the spray arm 115 is used to direct a cleaning liquid or fluid, such as a mixture of water and a cleaning agent, from the cleaning pump in a spray pattern onto the dishes or other items in the cleaning space 104 to remove soil therefrom. A rack (not shown) is provided in the washing tub higher than the height of the spray arm to hold, for example, dishes. Flexible electrical wires and conduits 111 couple the wash tank 101 to associated terminals within the cabinet 106, enabling the wash tank to be withdrawn from and retracted into the cabinet, while also enabling the supply of power and clean water to the wash tank, the removal of contaminated water from the wash tank, and optionally, control signals to be relayed to/from the apparatus.

A user interface unit 112 enabling a user to initiate various functions or washing programs of the dishwasher may be mounted in the cabinet 106, in the washing tub 101 (such as on the upper surface of the front panel 105 as shown), or may be provided remotely. User input from a user interface unit is provided to a dishwasher controller 113 disposed in the cabinet or wash tub, and the dishwasher controller 113 is programmable to generate electronic control signals for various machine components such as one or more displays, one or more motors, one or more heating elements and one or more valves during cycles of machine operation such as pre-wash, rinse and dry in response to user input instructions.

The cleaning apparatus 100 is generally configured to have a height dimension of about half that of a conventional front-loading household cleaning apparatus. In this form, the cleaning apparatus 100 may be used alone or as one of a plurality of such cleaning apparatuses, more typically one of a pair of such cleaning apparatuses, as shown in US 8397736. The washing system may be incorporated in other types of dishwashers, such as conventional "drop door" dishwashers or "table/counter top dishwashers. The washing system may also be incorporated into other types of washing apparatus, such as front or top loading, or even drawer type washing machines. In order to obtain an effective cleaning space in the cleaning chamber 104 of the reduced height cleaning apparatus 100, it is important that the pump of the present invention has a compact vertical height.

The cleaning tank upper surface 114 preferably includes a first opening 67 in the upper surface 114. Pump assembly 118 can be assembled and secured within the first opening. Pump assembly 118 is a combined washer pump 107 and drain pump 108 having separate washer pump impeller 95 and drain pump impeller 54 mounted on a common shaft 52, wherein the geometry of the impellers and their cavities in which they rotate ensure that shaft rotation in a first direction effectively activates the washer pump only, while shaft rotation in the opposite direction effectively activates the drain pump only. Preferably, the pump assembly, including the rotor 60, drive shaft 52 and the connected discharge pump impeller 54 and purge pump impeller 95, is removable from the first opening 67. This allows for simple cleaning or repair of the rotor and impeller unit. The pump assembly preferably has a suitable protrusion 122 in the upper bearing housing that locks into a lower protrusion 123 in the stator assembly by positioning and rotating the pump assembly.

Fig. 2 illustrates an embodiment in which a first opening for the pump assembly 118 is formed in the stator assembly or motor housing 62. The motor housing part 62 (including the stator 61, the discharge pump chamber, and the

conduits

68, 69 connected to the tub and the discharge portion) is fixed into the upper surface 114 of the tub base 102, or forms part of the upper surface 114 of the tub base 102. A removable rotor or pump assembly 118 may be connected to the motor housing 62 in the first opening 67. Preferably, the user can easily remove the rotor component 118 from the tub/drawer and will securely lock in place.

Fig. 2 and 3 show the washer pump impeller 95 protruding above the level of the upper surface of the base 114 formed by the motor housing 62. The cleaning pump impeller 95 draws cleaning fluid radially inwardly through the fluid or fluid inlet 86 and creates an upward axial outlet flow of cleaning fluid with the cleaning pump impeller 54. An outlet flow of cleaning fluid from the cleaning pump 108 is supplied to a spray arm 115, which spray arm 115 distributes cleaning fluid to the cleaning objects located in the cleaning volume 104.

Referring to fig. 3 to 5, the cleaning apparatus of the present invention uses a single motor to drive the cleaning pump impeller 95 and the discharge pump impeller 54 installed at opposite ends of the motor drive shaft 52. The rotor 60 of the motor is connected to the drive shaft 52, preferably between the purge pump impeller 95 and the discharge pump impeller 54, thereby forming part of the pump assembly. Preferably, the rotor 60 is splined or connected to the drive shaft 52, with the drive shaft 52 extending out of the opposite surface of the rotor where the upper portion of the drive shaft 52 carries the purge pump impeller 95 and the lower portion of the drive shaft 52 carries the discharge pump impeller 54. The stator 61 of the motor is mounted in the stator housing 62 below the upper surface 114 of the base 102 or forms the upper surface 114 of the base 102. The stator housing has a central opening that enables the pump assembly 118 to be removable and replaceable in the first opening 67 while maintaining a tight connection between the rotor and the stator. The rotor 60 is designed to operate when submerged in a fluid that acts as a lubricant. Preferably, this fluid comes only from the washing impeller 95 chamber to avoid mixing of dirty water from the discharge pump chamber.

The drive shaft 52 is radially supported for rotation about the longitudinal axis of the drive shaft 52 by upper and lower bearings 96, 97 disposed in respective upper and

lower bearing housings

98, 99. The upper bearing 96 and the lower bearing 97 do not rotate with the drive shaft. The first opening in which the pump assembly is placed is preferably formed by a central opening in the motor housing 62. The motor housing 62 is preferably formed of a lower housing portion 63 and an upper housing portion 64, the lower housing portion 63 and the upper housing portion 64 meeting at the interface 59.

The lower housing portion 63 of the housing 62 provides an outer shell or chamber within which the drain pump impeller 54 operates to pump wash water drained from a sump in the floor of the wash chamber 104 out of the sump and into the outlet conduit 56 (not shown in figures 3 to 5). The upper housing portion 64 of the housing 62 comprises a first portion 65 and a second portion 66, the first portion 65 being positioned substantially vertically in the dishwasher and surrounding the rotor 60, the second portion 66 being positioned substantially horizontally in the dishwasher, forming a substantially flat surface radially surrounding the pump assembly.

FIG. 5 shows a cross-section of the purge pump assembly of FIG. 4. Centered about the washer pump impeller 95 is a spray arm bearing 116 adapted to rotatably support a spray arm 115 resting thereon. The spray arm bearing 116 is mounted to a disc-shaped annular rotor chimney 84, which chimney 84 holds the spray arm bearing 116 in position relative to the upper bearing housing 99, and when the pump assembly is in place in the motor assembly relative to the bottom of the wash chamber 104 and motor housing 62. The rotor chimney 84 is preferably connected to the upper bearing housing by a plurality of ribs 87, the ribs 87 extending radially outward along the top of the upper bearing housing and upward to form a space between the upper bearing housing 98 and the rotor chimney 84. The rotor chimney preferably comprises a generally annular surface extending outwardly from around the washing impeller and/or the spray arm bearing. The spray arm bearing 116 supports the spray arm and allows the spray arm to rotate and provides a housing that closely surrounds the wash pump impeller 95. The lower surface of the rotor chimney provides a ceiling or ceiling above the stator housing because it forms the final feature before the wash pump chamber below the wash pump impeller 95. This forms a closed annular channel (between the rotor chimney and the stator assembly/wash tub base) to the wash pump through which wash liquid flows. The rotor chimney 84 may have other features, such as means for aligning the pump assembly.

The washer pump impeller 95 includes a plurality of radial vanes 94 extending along an upper portion of the drive shaft 52. The radial blades 94 preferably extend outwardly from a central impeller hub of the washer pump impeller 95. The spray arm 115 has a circular opening in the base of the spray arm so that at least part of the washer pump impeller 95 rests within a cavity in the spray arm. This means that when the wash pump impeller is operated in a forward direction, water moves from the fluid inlet port 86, through the impeller, and into the spray arms from which it is directed into the wash chamber 104. The radial vanes 94 have an upper edge which in use is located inwardly of the spray arm and a lower edge 93 which faces the upper bearing housing.

The prior art pumps have performance that is inconsistent with pump priming. Surprisingly, it has been found that the axial position of the washer pump impeller 95 relative to the washer pump water inlet (fluid inflow port 86 of the washer pump 107) is an important parameter for achieving a consistent and early start of the washer pump 107. By positioning the plurality of radial vanes 94 such that the lower edge 93 of each of the plurality of radial vanes 94 is above the upper edge 88 of the wash pump inlet 86, uniformity of wash performance is improved.

Fig. 5 shows that the purge pump water inlet 86 has an upper edge that is initially formed by the bottom edge or surface of the spray arm bearing 116 and then by the lower surface 85 of the rotor chimney member 84. This arrangement produces advantageous results associated with rapid and consistent pump activation believed to be caused by less turbulent water or fluid intake by the pump during activation. The upper surface 88 of the purge pump fluid inlet 86 may be formed by alternate means, such as the lower surface of the rotor chimney may extend to the impeller 94 with the spray arm bearing disposed above the impeller 94, or a separate component or surface may be designed to provide the desired profile. In each case, however, the impeller is located above the fluid inlet.

In the embodiment shown in fig. 3, 4 and 5, the rotor chimney member 84 also defines an upper boundary of an annular passage 90 between the rotor chimney member 84 and the housing 106, the annular passage 90 being configured to channel or direct water from the interior of the wash chamber 104 to the wash pump impeller 95. Those skilled in the art will appreciate that this annular passage 90 may form part of the purge pump water inlet 86 at or near the end where the purge pump water inlet 86 meets the purge pump impeller, or at least become part of the purge pump water inlet 86. Preferably, the lower edge 117 of the spray arm bearing 116 is substantially flush with the lower surface 85 of the rotor chimney member 84.

Fig. 3 shows that the second portion 66 of the upper housing portion or portion of the motor housing 62 and the top surface 120 of the upper bearing housing 98 define a generally flush surface that defines the lower boundary of the channel 90 through which the liquid is directed to the washer pump impeller 95. Preferably, this forms a fluid flow inlet 86 to the lower edge or floor of the wash pump. Thus, in use, fluid is drawn from the cleaning chamber 104 along the passage 90 between the motor housing 62 and the rotor chimney 84 before entering the fluid flow inlet 86 to the cleaning pump impeller 95 and being directed to the spray arm 115. A fluid flow inlet is formed at the point where the fluid enters the cavity between the bottom of the wash impeller and the bottom plate, preferably by the top surface of the upper bearing housing 64. This extends radially around the purge pump impeller, preferably 360 degrees around the purge pump impeller, forming a radial chamber or plenum. In the illustrated embodiment, the fluid flow inlet 86 and the channel 90 are defined by the upper surfaces of the spray arm bearing, the rotor chimney 84, the upper bearing housing 98, and the stator housing 62. In fig. 3, the fluid flow inlet is defined by the base of the spray arm bearing 116, which occurs approximately at the outer diameter of the upper bearing housing 98 or the radius of the first opening 67 where the pump assembly is inserted into the base. Figure 3 shows that in use, fluid level at the top of the fluid flow inlet does not reach the impeller blades. The fluid flow inlet may be considered a height restriction of the fluid flow path before the fluid enters the cleaning chamber beneath the impeller of the cleaning pump.

In an embodiment of the invention, the gap 120 between each of the plurality of radial blades 94 and the bearing housing 100 on the top surface is between 4mm and 10mm, preferably between 6mm and 7mm, and most preferably 6.7mm. In an embodiment of the invention, the gap 120 between the lower edge 93 of each of the plurality of radial vanes 94 and the top of the water flow inlet is greater than or equal to 0.5mm, preferably greater than or equal to 1mm, and most preferably 1.7mm. Preferably, the gap is less than 2mm. Preferably, the upper surface of the washing impeller hub 138 is between 10mm and 15mm above the top surface of the spray arm bearing, and most preferably between 12.6mm above the top surface of the spray arm bearing.

Referring to fig. 5-7, when pump assembly 118 is positioned within stator assembly 62, lower bearing housing 99, which is disposed below drive shaft 52, separates upper chamber 72 for cleaning the impeller from lower chamber 73 for discharging the impeller. The lower surface 125 of lower bearing housing 99 forms the upper surface of lower chamber 73 and the upper surface of lower bearing housing 99 forms the lower surface of the upper chamber. The outer walls of the upper and

lower chambers

72, 73 are formed by the motor housing 62, and the pump assembly is located within the motor housing 62 in use. The upper chamber 72 preferably at least partially surrounds the rotor 60, the rotor 60 is preferably a plurality of ferrite cores or pieces, and the lower chamber 73 surrounds the discharge pump impeller 54. The discharge pump impeller 54 is in rotational engagement with the drive shaft 52 and, as shown in FIG. 2, is adapted to receive water from the wash chamber 104 through conduit 68 and pump the water to the outlet through conduit 69.

Lower bearing housing 99 is configured to be disposed on or pressed against seat, flange, or annular projection 74 of upper housing portion 64 when pump assembly 118 is positioned within stator assembly 62. Preferably, the lower bearing housing 99 has a corresponding annular protrusion 81 or lip that mates with the flange 74. This interface forms a seal between the upper chamber 72 and the lower chamber 73. The lower bearing housing 101 is mounted on the drive shaft 52 by a lower bearing 97 between the lower surface of the rotor 105 and the uppermost edge surface of the discharge pump impeller 54.

The rotation of the rotor 60 (and thus the attached impeller) requires a clearance between the rotor 60 and the upper chamber. However, because of the presence of water or other liquids in the upper and

lower chambers

72, 73 during the cleaning cycle, it is possible, but undesirable, for fluids to move between the chambers. Preventing contaminated cleaning fluid from entering the upper chamber 72 reduces wear on the rotor 60 and prevents clogging of the rotor 60.

Surprisingly, it has been found that the seal between the flange 74 of the stator assembly 62 and the annular projection 81 of the lower bearing housing is easily moved when the discharge pump is in operation. This is because sufficient discharge pump pressure is established such that an upward force on the lower bearing housing 99 may cause the lower bearing housing 99 to slidably move relative to the housing 62, thereby overcoming any seal and causing the flange 74 and annular protrusion 81 to move apart and allow fluid to enter the upper chamber 72.

To ameliorate this potential leakage, lower bearing housing 99 includes an annular seal 70 to seal a circumferential gap 79 between an outer surface 103 of lower bearing housing 99 and an outer surface 71 of stator assembly 62 from liquid. This prevents fluid from entering upper chamber 118 around the edges from lower bearing housing 119 even as movement of the lower bearing housing occurs. Fig. 6A and 6B show the lower bearing housing 99 with the annular seal 70. The annular seal is below the annular projection 81 or between the annular projection or lip and the lower surface of the lower bearing housing. The annular seal 70 preferably has a substantially flat portion 133 and a lip 134, the lip 134 extending from the seal to contact the housing 62 when the pump assembly is positioned in the stator assembly. The lip preferably has a point or tip at the outermost end. Preferably, the lip has a generally flat upper surface and a lower surface angled from the tip to the flat. Alternatively, an O-ring seal may be used. Advantageously, the seal may also reduce vibration and thus noise, as the seal provides a second soft contact between the stator assembly and the pump assembly (the first contact is locking the upper bearing housing to the stator housing).

In some embodiments, the ring seal 70 is overmolded or co-molded to the lower bearing housing 99 and/or comprises an elastomeric material. In the embodiment shown in fig. 6B, the outer surface 103 of the lower bearing housing 99 includes an annular recess that receives the annular seal 70 and defines its axial position relative to the lower bearing housing 99 and when in position in the housing 62. The use of an overmolded seal reduces the number of parts for the user and ensures that the seal is properly positioned.

Fig. 7A shows the pump assembly in place within stator assembly 62. The upper and

lower housing portions

64 and 63 of the stator housing or assembly 62 are preferably hot plates welded together to form a continuous and watertight seal at the interface 59. The upper housing portion 64 includes an annular upper interface portion 75 and the lower housing portion 63 includes an annular lower interface portion 76 that are oriented substantially perpendicular to the drive shaft 52 and are configured to be thermally welded together to form a continuous and impermeable housing. Preferably, the annular seal 70 is disposed above the intersection of the housing portions. This ensures that the seal is not affected by any excess material on the surfaces of the

housing parts

63, 64 due to the welding or joining of the

housing parts

63, 64.

To further reduce any fluid leakage between the lower chamber 73 and the upper chamber 74, the lower bearing housing 99 includes a plurality of tabs or legs 130 extending from the lower bearing housing 99 in a direction parallel to the drive shaft 52 toward the upper bearing housing 98, which upper bearing housing 98 is disposed at an upper portion of the drive shaft 52. In fig. 6A, there are shown preferably 3 legs 130, the legs 130 being designed to transfer any forces generated by the upward sliding of the lower bearing housing 99 to the upper bearing housing 98. Since the upper bearing housing is preferably fixed to the motor housing 62 by means of the

projections

122, 123, but may alternatively be fixed to the washing chamber 104 or the base 102, this prevents relative movement of the lower bearing housing 99 and the housing 62. Fig. 6A shows an additional shorter leg 131 extending in the same direction as leg 130. The additional leg is used to orient the pump assembly 118 in the housing 62.

Fig. 8 is a horizontal cross-section of the stator assembly and pump assembly, showing legs 130 located in stator assembly 62. The housing 62 has a passage 57 in the upper housing part 64 extending parallel to the drive shaft 52 in the central opening to accommodate the

legs

130, 131 in use. The legs 130 are preferably slightly offset outwardly from the drive shaft 52. This outward bias ensures a secure connection between the legs and the channel surface in the housing 62 when fitted into the channel.

In addition, as shown in detail in fig. 7A, each tab or leg 130 includes an upper portion 126, the upper portions 126 presenting interlocking features 127 on their mating surfaces. The interlocking features are adapted to interlock with corresponding interlocking features 128 of the upper bearing housing 98 to prevent any sliding or movement of the mating surfaces of the legs 130 under load. This prevents the lower bearing housing 99 from moving, particularly from vertical as well as horizontal movement. The interlocking features 127, 128 preferably have a plurality of different flats to prevent movement of forces in different directions. Preferably, each of the interlocking features has at least two flats, preferably four flats, on their upper and lower surfaces or interface surfaces. The planes have different slopes or angles to provide resistance to movement in different directions.

FIG. 7B shows in detail an interface implementation: a leg having an interlocking feature 127, the interlocking feature 127 having a chamfered or angled portion 129 and a flat surface 133 that is substantially perpendicular to the drive shaft 62. Two further inclined portions are provided on either side of the inclined portion 129. Corresponding surfaces are present on the meeting faces of the upper bearing housing. In use, the flat portion provides a stopping force against any vertical movement, while the inclined portion improves contact between the faces. Preferably, the interface has a substantially flat or horizontal portion and an inclined portion to provide a solid interface and lock or guide the legs into place. The interface surface, i.e. the top surface of the leg, has four flat surfaces on the contact surface from the left side of fig. 7B: a flat or horizontal surface, a vertical surface, a first inclined surface and a second inclined surface, wherein the second inclined surface has a lower inclination or angle. The sides of the channel will support or meet the left and right sides of the leg.

Channels in the housing 62 guide the legs to ensure a secure fit between the interlocking features. In figure 7B, the legs are positioned in their naturally biased position and thus extend into the stator housing, which in use pushes the legs tightly against the upper bearing housing when the pump assembly is inserted. The use of an interlocking design improves a simple angled interface as it provides a blocking interface for axial movement, while the angled interface will allow the end to slide relative to the upper bearing housing, overcoming with only a small friction force.

In case a limited movement of the lower bearing housing is possible, due to the interlocking legs, additional pressure is exerted on the legs themselves. To address this pressure, the legs 130 are thickened to increase rigidity. This presents difficulties due to the small tolerances in the motor housing 62, as shown in fig. 8, where the channels that receive the legs are located between the stator windings 58. Advantageously, the legs extend in width to substantially fill the gap or space between adjacent stator cores (with the required channel housing). Preferably, the base of the leg 130 has a depth (from the outer surface towards the drive shaft) of between 2.5mm and 3.5mm, most preferably 2.9mm, and a width of 3mm to 4mm, most preferably 3.3mm. Preferably the top of the leg has a depth of 2mm to 3mm, most preferably 2.5mm, and a width of 2mm to 3mm, most preferably 2.6mm. Preferably, the width of the legs 130 is such that the channels in which they are positioned in use substantially fill the space between adjacent stator windings.

As described in more detail in US8397736, the discharge impeller 54 preferably has a plurality of radial blades connected to the central impeller hub 40. The drain impeller 54 pumps water from a sump in the cleaning chamber 104 to an outlet or drain. To improve performance, the discharge impeller 54 has a hub that mates with the lower bearing housing 99 and the base of the housing 62. An annular channel in which the vanes of the discharge impeller are located is formed between the hub and the housing 62. The annular passage begins at a fluid inlet 57 near the inlet side of the dividing wall portion and extends circumferentially around the center hub 102 and the impeller hub 40 to terminate at a fluid outlet near the outlet side of the dividing wall portion.

To reduce air accumulation in the lower chamber 73 during venting of the sloped ramp surface on the lower surface of the lower bearing housing 99, a central hub around the lower surface of the lower bearing housing 99 is preferred. The inclined slope surface is higher near the inlet side of the partition wall portion and lower near the outlet side of the partition wall portion, and is inclined between the outlet side and the inlet side of the partition wall portion. This means that air is automatically discharged out of the lower chamber.

Claims

1. A pump assembly for use with a spray arm in a cleaning chamber of a cleaning apparatus, the pump assembly comprising:

a drive shaft;

a rotor coupled to the drive shaft;

a discharge pump impeller mounted to the drive shaft, the discharge pump impeller configured to pump water into a discharge;

a wash pump impeller mounted at an upper end of the drive shaft, the wash pump impeller including a plurality of radial vanes extending along at least a portion of the drive shaft, the wash pump impeller configured to draw fluid from a fluid flow inlet and generate an upward axial outlet flow of the fluid,

wherein a lower edge of each of the plurality of radial vanes is above an upper surface of the fluid flow inlet.

2. The pump assembly of claim 1, further comprising a spray arm bearing, wherein the spray arm bearing is retained in position relative to the pump assembly, a lower edge of the spray arm bearing forming an upper surface of the fluid flow inlet.

3. The pump assembly of claim 2, further comprising an annular rotor chimney that supports the spray arm bearing in place.

4. The pump assembly of claim 3, wherein a lower edge of the spray arm bearing is flush with a lower surface of the annular rotor chimney and forms an upper surface of the fluid flow inlet.

5. The pump assembly of claim 1, further comprising an annular rotor chimney, wherein a lower surface of the annular rotor chimney forms an upper surface of the fluid flow inlet.

6. The pump assembly of claim 1, wherein the pump assembly is configured to be insertable into a pump housing in a base of the cleaning apparatus.

7. The pump assembly of claim 6, wherein a pump housing in the base of the cleaning apparatus houses a stator configured to engage with a rotor of the pump assembly to form a motor arrangement configured to rotate the drive shaft.

8. The pump assembly of claim 6, wherein the upper surface of the pump housing in the base of the cleaning apparatus is a lower surface of the fluid flow inlet.

9. The pump assembly of claim 8, further comprising an upper bearing housing containing the drive shaft, the upper bearing housing forming a floor below the washer pump impeller, wherein an upper surface of the upper bearing housing defines a surface that is flush with the upper surface of the pump housing.

10. The pump assembly of claim 9, wherein a gap between a lower edge of each of the plurality of radial vanes and a surface of the upper bearing housing is less than or equal to 10mm.

11. The pump assembly of claim 2, comprising a spray arm that rotationally rests on the spray arm bearing, the spray arm including a circular opening in a base thereof such that at least a portion of the purge pump impeller rests within a cavity in the spray arm.

12. The pump assembly of claim 1, wherein a distance between a lower edge of each of the plurality of radial vanes and an upper surface of the fluid flow inlet is between 1mm and 2mm.

13. The pump assembly of claim 1 wherein said purge pump impeller and said discharge pump impeller are mounted at opposite ends of said drive shaft.

14. A cleaning device comprising a pump assembly according to claim 1, wherein the cleaning device is a drawer dishwasher, the dishwasher chamber being slidably mounted within a cabinet.