EP3201472A1

EP3201472A1 - Fan assembly for cooking oven with improved energy consumption

Info

Publication number: EP3201472A1
Application number: EP14777578.7A
Authority: EP
Inventors: Ihsan Arslantekin; Merih Tarimtoru; Altan OZKOK
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2014-09-29
Filing date: 2014-09-29
Publication date: 2017-08-09
Anticipated expiration: 2034-09-29
Also published as: WO2016050259A1; PL3201472T3; EP3201472B1; TR201511087A1

Abstract

The present invention relates to a fan assembly comprising a motor (3) which has a shaft (4) and a fan (5) which has a blade (6) and a hub (7). The hub (7) has a bore (8) for supporting the shaft (4). In the fan assembly (1) of the present invention the shaft (4) has a snap-fit connector (9a) and the hub (7) has a counterpart snap-fit connector (9b) for mutual engagement so as to secure the hub (7) against relative axial displacement with respect to the shaft (4) and the shaft (4) has at least one anchoring rib (10) and the hub (7) has a mating sleeve (11) for clamping the surface of the bore (8) against each anchoring rib (10) of the shaft (4) so as to secure the hub (7) against relative rotation with respect to the shaft (4).

Description

FAN ASSEMBLY FOR COOKING OVEN WITH IMPROVED ENERGY CONSUMPTION

The present invention relates to a fan assembly suitable for use in a household appliance, in particular a cooking oven.
During the cooking process usually a large amount of heat is generated inside the cooking chamber. Therefore, a cooking oven is generally provided with a ventilation unit which has a fan assembly for discharging the hot air to the outside. The overall cost of the cooking oven and the energy efficiency of the cooking oven are also influenced by the ventilation unit, in particular by the fan assembly. In general, a prior art fan assembly has a motor and a metal fan which is releasably connectable to the shaft of the motor by a thread connection. The shaft usually has a flange and a thread at its free end. The free end of the shaft usually has a D-shaped cross section. The hub of the fan usually has a mating D-shaped bore for receiving the free end of the shaft. When assembling the prior art fan assembly, the free end of the shaft is penetrated through the bore until the hub is seated onto the flange. Subsequently, a resilient ring and a nut are fixed onto the thread of the free end of the shaft which protrudes through the hub.
A drawback of the prior art fan assembly is that it renders the production, the assembly and the maintenance labor and cost intensive. Moreover, due to the complicated assembly there is a risk that the component parts to be assembled are not correctly connected. In addition, the bulky and heavy structure of the prior art fan assembly requires a comparatively powerful motor with a relatively large package. However, such motor increases the energy consumption and reduces the utilizable volume of the cooking oven. Thus, the ventilation performance of the cooking oven is degraded.
An objective of the present invention is to provide a fan assembly and a cooking oven having the same which overcomes the aforementioned drawbacks of the prior art in a cost effective way and which is relatively small sized and light weight and which enables an improved production, assembly and maintenance and which also enables an improved energy consumption and ventilation performance.
This objective has been achieved by the fan assembly as defined in claim 1 and the cooking oven as defined in claim 12. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.
In the fan assembly of the present invention, the shaft comprises a snap-fit connector and the hub comprises a counterpart snap-fit connector which mutually engage and secure the hub against relative axial displacement with respect to the shaft. In the fan assembly of the present invention, the shaft further comprises at least one anchoring rib and the hub comprises a mating sleeve which clamps the surface of the bore against each anchoring rib of the shaft and secures the hub against relative rotation with respect to the shaft.
In an embodiment, the snap fit connectors respectively comprise a locking notch formed into the shaft and at least one locking claw formed onto a corresponding resilient supporting arm of the hub, which do not interfere with the clamping sleeve. As the shaft is inserted through the hub, the locking claws ride on the shaft and snap-fit into the locking notch. Thereby the fan is secured against relative axial displacement with respect to the shaft. In a version of this embodiment, the locking notch is circular shaped.
In another version of this embodiment, the locking notch and the supporting arms are freely accessible in the assembled state. Thereby, the fan can be easily disassembled from the motor for maintenance by dislodging the locking claws out of the locking notch.
In another embodiment, each anchoring rib has a sharp protruding edge which is integrally formed onto the shaft. The protruding edge can be formed onto the shaft by a suitable metal working process such as forging. In the clamped state each edge remains wedged inside a corresponding mating groove carved by the edge itself during the clamping. Thereby, the fan can be further secured against relative rotation with respect to the shaft.
In another embodiment, the hub is rendered flexible by a gap. Thereby, the hub can be more effectively clamped by the sleeved onto the shaft.
In a version of this embodiment, the hub has a stopper which restricts the downwards movement of the sleeve. Thereby, the sleeve can be held at its position.
In another version of this embodiment, the hub is cylindrical-shaped and the mating sleeve is ring-shaped.
In another embodiment, each anchoring rib extends substantially straight along the shaft.
In another embodiment, the shaft has a plurality of anchoring ribs some of which are inclined in opposite directions relative to the others in order to improve the grip between the shaft and the hub.
In another embodiment, the fan is made of a plastic material. Thereby, the fan is rendered light weight and the torque can be reduced.
The present invention also provides a cooking oven comprising a ventilation unit which has the fan assembly according to the present invention.
In another embodiment, an aperture is formed into the duct of the ventilation unit. The fan is immersed through the aperture into the duct. The aperture is also fluidly connected with the control unit. Thereby, the control unit can be effectively ventilated via the duct and the temperature of the thermally sensitive electrical components of the control unit can be kept well below the safety limit to prevent a breakdown. During the cooking process usually a large amount of steam is generated inside the cooking chamber. A satisfactory completion of the cooking process requires the steam inside the cooking chamber to be effectively exhausted to the outside. In the present invention the duct is also fluidly connected to the cooking chamber via an openable/closable chimney. Thereby, the hot humid air inside cooking chamber can also be effectively discharged to the outside.
In another embodiment, the door is also cooled by the ventilation unit. Thereby, the temperature of the door, in particular the handle and the glass pane can be kept well below dangerous temperature limits to protect the user from skin burns and scalding.
With the present invention, particularly by virtue of the snap-fit connectors, the anchoring rib and the clamping sleeve, the need for utilizing a thread connection, in particular the need for forming a thread and a flange on the shaft and forming the mating D-shaped structures on the shaft and the hub have been completely obviated. With the present invention, the fan assembly has been structurally simplified and the number of components has been reduced. Thereby, the cost for production, assembly and maintenance has been reduced. With the present invention, the fan assembly has been rendered relatively small sized and light weight. Thereby, the ventilation performance and the energy efficiency have been improved. With the present invention the consumer satisfaction can be increased. In addition with the present invention, particularly by virtue of the anchoring rib and the clamping sleeve, the connection between the shaft and the hub has been further improved and the risk of slippage has been eliminated even at comparatively high rotational speeds and high torques. Thereby, the ventilation process can be reliably conducted and the cooking oven can be prevented from breakdown and causing any hazards to the customer by its hot parts.
Additional advantages of the fan assembly of the present invention and the cooking oven of the present invention will become apparent with the detailed description of the embodiments with reference to the accompanying drawings in which:
Figure 1 – is a schematic partial perspective view of a cooking oven which has a fan assembly according an embodiment of the present invention.
Figure 2 – is a schematic front perspective view of the fan assembly according to an embodiment of the present invention,
Figure 3 – is a schematic rear perspective view of the fan assembly of Fig. 2,
Figure 4 – is a schematic partial vertical sectional view of the fan assembly of Fig. 2,
Figure 5 – is a schematic front perspective view of the fan of Fig. 2, prior to assembling with the motor,
Figure 6 – is a schematic rear perspective view of the fan of Fig. 2, prior to assembling with the motor,
Figure 7 – is a schematic front perspective view of the motor of Fig. 2, prior to assembling with the fan,
Figure 8 – is a schematic enlarged view of the detail A of Fig. 7,
Figure 9 – is a schematic vertical cross sectional view of the shaft of Fig. 8.
The reference signs appearing on the drawings relate to the following technical features.

Fan assembly
Cooking oven
Motor
Shaft
Fan
Blade
Hub
Bore

9a. Connector
9b. Connector
10. Rib
10a. Edge
11. Sleeve
12. Notch
13. Claw
14. Arm
15. Gap
16. Stopper
17. Wall
18. Slit
19. Ventilation unit
20. Duct
21. Aperture
22. Frame
The fan assembly (1) is suitable for use in a household appliance (2), in particular a
cooking oven (2). The fan assembly (1) comprises a motor (3) which has a shaft (4) and a fan (5) which has a blade (6) and a hub (7). The hub (7) has a central bore (8) for supporting the shaft (4) (Fig. 1 to 9).
In the fan assembly (1) of the present invention, the shaft (4) has a snap-fit connector (9a). The hub (7) has a counterpart snap-fit connector (9b) which engages with the snap-fit connector (9a) of the shaft (4) so as to secure the hub (7) against relative axial displacement with respect to the shaft (4). In the fan assembly (1) of the present invention, in addition, the shaft (4) has one or more than one anchoring rib (10). The hub (7) has a mating sleeve (11) for clamping the surface of the bore (8) against each anchoring rib (10) of the shaft (4) so as to secure the hub (7) against relative rotation with respect to the shaft (4).
In an embodiment, the snap-fit connector (9a) has a locking notch (12) which is formed into the circumferential surface of shaft (4). In this embodiment, the counterpart snap-fit connector (9b) has one or more than one locking claw (13) for snap-fitting into the locking notch (12) as the shaft (4) is inserted into the bore (8). In addition, the counterpart snap-fit connector (9b) also has one or more than one resilient supporting arm (14). Each locking claw (13) is formed on the corresponding supporting arm (14). Each supporting arm (14) is formed onto the hub (7) and extends in an axial direction of the shaft (4). In the inserted state each locking claw (13) remains snap-fitted inside the locking notch (12) and secures the fan (5) against relative axial displacement with respect to the shaft (4).
In another embodiment, the locking notch (12) is located between the free end of the shaft (4) and the anchoring rib (10). In addition, each supporting arm (14) is located on the free end of the hub (7) which is averted from the motor (3).
In another embodiment, the hub (7) has two supporting arms (14) which are diametrically opposed to each other.
In another embodiment, each anchoring rib (10) has a sawtooth shaped edge (10a) which is integrally formed onto the circumferential surface of the shaft (4) and protrudes a predetermined distance from the shaft (4). Each edge (10a) carves a mating groove into the inner surface of the bore (8) as the shaft (4) is inserted and clamped in the bore (8). In the clamped state each edge (10a) remains wedged inside the corresponding mating groove and secures the fan (5) against relative rotation with respect to the shaft (4).
In another embodiment, the fan assembly (1) comprises a gap (15) for rendering the hub (7) flexible. The gap (15) is formed into the hub (7). The sleeve (10) is clamped onto the hub (7) at the level of the gap (15).
In another embodiment, the fan assembly (1) comprises a stopper (16) for blocking a forward movement of the sleeve (11). The stopper (16) is formed onto the hub (7) at the level of the gap (15).
In another embodiment, the hub (7) comprises a cylindrical-shaped wall (17) which defines the bore (8). In this embodiment, the gap (15) comprises two diametrically opposing slits (18) formed into the cylindrical-shaped wall (17). In this embodiment, the sleeve (10) is ring-shaped and mates with the cylindrical-shaped wall (17).
In another embodiment, each anchoring rib (10) extends straight along the axial direction of the shaft (4).
In another embodiment, the shaft (4) has four anchoring ribs (10) which are evenly spaced around the axis of the shaft (4). Two of the anchoring ribs (10) are inclined towards the clockwise direction. The other two anchoring ribs (10) are inclined towards the anti-clockwise direction.
In another embodiment, the fan (5) is a single piece of plastic material which is heat resistant.
The cooking oven (2) comprises a casing which encloses a cooking chamber for cooking food, a door for accessing the cooking chamber, a heater unit for heating the interior of the cooking chamber, a control unit which has a user-interface and a ventilation unit (19) for discharging hot air to the outside. The control unit controls the operation of the heater unit, the user-interface and the ventilation unit (Fig. 1 to 9).
In the cooking oven (2) of the present invention the ventilation unit (19) comprises the fan assembly (1).
In another embodiment, the ventilation unit (19) further comprises a duct (20) for conveying the hot humid air to the outside. The duct (20) is disposed on and fluidly connected to the cooking chamber. The ventilation unit (19) further comprises an aperture (21) for immersing the fan (5) of the fan assembly (1) into the duct (20). The aperture (21) is formed into the duct (20) and is fluidly connected to a region in the proximity of the control unit. The ventilation unit (19) further comprises a frame (22) for retaining the motor (3) of the fan assembly (1). The frame (22) is detachably mountable around the aperture (21).
In another embodiment, the ventilation unit (19) is further configured to ventilate the door. In this embodiment, the duct (20) is fluidly connected to one or more than one region in the proximity of the door.
With the present invention, particularly by the snap fit connection and the clamping connection the structure of the fan assembly (1) has been simplified. Thereby, the need for utilizing the prior art thread connection has been obviated. With the present invention, the cost for production, assembly and maintenance of the fan assembly has been reduced. With the present invention, particularly the diameter of the shaft (4), the weight of the fan (5), the wattage of the motor (3) and the size of the motor (3) package have been substantially reduced. Thereby, the ventilation performance and the energy efficiency have also been improved. With the present invention the consumer satisfaction can be increased.

Claims

A fan assembly (1) for use in a household appliance (2), in particular a

cooking oven (2), the fan assembly (1) comprising

- a motor (3) which has a shaft (4) and

- a fan (5) which has a blade (6) and a hub (7), wherein the hub (7) has a central bore (8) for supporting the shaft (4),

characterized in that

- the shaft (4) has a snap-fit connector (9a) and the hub (7) has a counterpart snap-fit connector (9b) which are configured to mutually engage and secure the hub (7) against relative axial displacement with respect to the shaft (4) and

- the shaft (4) has one or more than one anchoring rib (10) and the hub (7) has a mating sleeve (11) configured to clamp the surface of the bore (8) against each anchoring rib (10) of the shaft (4) and secure the hub (7) against relative rotation with respect to the shaft (4).
The fan assembly (1) according to claim 1, characterized in that

- the snap-fit connector (9a) has a locking notch (12) which is formed into the circumferential surface of shaft (4) and

- the counterpart snap-fit connector (9b) has one or more than one locking claw (13) configured to snap-fit into the locking notch (12) as the shaft (4) is inserted into the bore (8) and one or more than one resilient supporting arm (14), wherein each locking claw (13) is formed on the corresponding supporting arm (14) and wherein each supporting arm (14) is formed onto the hub (7) and extends in the axial direction of the shaft (4) and in the inserted state each locking claw (13) remains snap-fitted inside the locking notch (12) and secures the fan (5) against relative axial displacement with respect to the shaft (4).
The fan assembly (1) according to claim 2, characterized in that the locking notch (12) is located between the free end of shaft (4) and the anchoring rib (10) and each supporting arm (14) is located on the free end of the hub (7) which is averted from the motor (3).
The fan assembly (1) according to claim 2 or 3, characterized in that the hub (7) has two supporting arms (14) which are diametrically opposed to each other.
The fan assembly (1) according to any one of claims 1 to 4, characterized in that each anchoring rib (10) has a sawtooth shaped edge (10a) which is integrally formed onto the circumferential surface of the shaft (4) and protrudes a predetermined distance from the shaft (4), wherein each edge (10a) carves a mating groove into the inner surface of the bore (8) as the shaft (4) is inserted and clamped in the bore (8) and in the clamped state each edge (10a) remains wedged inside the corresponding mating groove and secures the fan (5) against relative rotation with respect to the shaft (4).
The fan assembly (1) according to any one of claims 1 to 5, characterized in that a gap (15) configured to render the hub (7) flexible, wherein the gap (15) is formed into the hub (7) and wherein the sleeve (10) is clamped onto the hub (7) at the level of the gap (15).
The fan assembly (1) according to claim 6, characterized in that a stopper (16) configured to block a forward movement of the sleeve (10), wherein the stopper (16) is formed onto the hub (7) at the level of the gap (15).
The fan assembly (1) according to claim 6 or 7, characterized in that the hub (7) comprising a cylindrical-shaped wall (17) which defines the bore (8) and the gap (15) comprising two diametrically opposing slits (18) formed into the cylindrical-shaped wall (17), wherein the sleeve (11) is ring-shaped and mates with the cylindrical-shaped wall (17).
The fan assembly (1) according to any one of claims 1 to 8, characterized in that each anchoring rib (10) extends straight along the axial direction of the shaft (4).
The fan assembly (1) according to any one of claims 1 to 9, characterized in that the shaft (4) has four anchoring ribs (10) which are evenly spaced around the axis of the shaft (4), wherein two of the anchoring ribs (10) are inclined towards the clockwise direction and the other two anchoring ribs (10) are inclined towards the anti-clockwise direction.
The fan assembly (1) according to any one of claims 1 to 10, characterized in that the fan (5) is a single piece of plastic material.
A cooking oven (2), in particular a built-in type cooking oven (2) comprising

- a casing which encloses a cooking chamber for cooking food,

- a door for accessing the cooking chamber,

- a heater unit for heating the interior of the cooking chamber,

- a control unit which has a user-interface and

- a ventilation unit (19) for discharging hot air to the outside, wherein the control unit controls the heater unit, the user-interface and the ventilation unit,

characterized in that

the ventilation unit (19) comprising the fan assembly (1) as defined in any one of claims 1 to 11.
The cooking oven (2) according to claim 12, characterized in that

- a duct (20) for conveying the hot humid air to the outside, wherein the duct (20) is disposed on and fluidly connected to the cooking chamber,

- an aperture (21) for immersing the fan (5) of the fan assembly (1) into the duct (20), wherein the aperture (21) is formed into the duct (20) and is fluidly connected to a region in the proximity of the control unit and

- a frame (22) for retaining the motor (3) of the fan assembly (1), wherein the frame (22) is detachably mountable around the aperture (21).
The cooking oven (2) according to claim 13, characterized in that the ventilation unit (19) is further configured to ventilate the door, wherein the duct (20) is fluidly connected to one or more than one region in the proximity of the door.