Cooling fan of a motor vehicle

Abstract

The invention relates to a cooling fan (1), comprising a fan wheel (2) and a fan motor (3) which is connected to a pot-like hub housing (4) of the fan wheel (2), wherein the fan motor (3) has an external rotor (10) which is arranged to rotate about a motor axis (D) and has a pot-like rotor housing (12) which is seated in the hub housing (4) of the fan wheel (2) and is latched thereto, producing a number of snap connections.

Description

[0001] Page 1

[0002] 2024561 WO

[0003] Description

[0004] Radiator fan of a motor vehicle

[0005] The invention relates to an electrically (electromotor) driven radiator fan, in particular of a motor vehicle, with a fan wheel and with a fan motor which is connected to or can be mounted in a hub housing of the fan wheel.

[0006] Modern internal combustion engines, especially four-stroke engines in motor vehicles, are typically cooled by a coolant that circulates over the engine. The coolant absorbs the heat energy generated by the combustion engine and dissipates it. The heated coolant then flows through a heat exchanger, also known as a radiator, which is located at the front of the vehicle. An airflow through the radiator absorbs the heat energy from the coolant and cools it down before the cooled coolant flows back to the engine, thus completing the coolant circuit.

[0007] To move air through the radiator, a radiator fan, also known as a fan system or fan assembly, is provided in the direction of airflow, either upstream of the radiator (upstream) or downstream. This fan typically features an electrically driven impeller as the air-moving element. Such an impeller is usually rotatably mounted within a recess in the fan housing, which is a continuous opening in the fan housing. The fan housing is typically connected to the radiator, forming a radiator fan module.

[0008] Such a radiator fan typically uses an electric motor as its drive mechanism. The electric motor is preferably brushless.

[0009] 2024561 WO Page 2 Designed as a brushless direct current (BLDC) motor. For this purpose, the electric motor has electrical coils connected together to form a stator or rotating field winding, which are energized by motor electronics. A brushless direct current (BLDC) motor, also known as an electronically commutated electric motor, is a synchronous motor that uses direct current (DC) to generate mechanical energy by rotating a rotor. Such an electric motor, as an electric (three-phase) machine, typically has a stator equipped with the rotating field or stator winding, which is arranged coaxially with a rotor containing a number of permanent magnets, spaced apart by an annular gap or air gap. During operation, the stator winding generates a rotating magnetic field, which causes a torque on the permanently excited rotor.

[0010] The rotor is designed as an external rotor, which is arranged coaxially outside the stator. The external rotor typically has a rotatably mounted rotor housing (rotor bell, pole piece) as a magnetic return (rotor yoke), on the inner wall of which the permanent magnets (rotor magnets) are arranged. In such an external rotor motor, the stationary stator is arranged radially inside the rotor, which rotates around a motor or rotor axis, so that during operation of the electric motor, the rotor rotates around the stator.

[0011] The external rotor of the electric motor used as a radiator fan drive is arranged in a hub housing to which radially oriented fan blades are integrally formed. For this purpose, the preferably cup-shaped rotor housing is inserted into and attached to the similarly preferably cup-shaped hub housing of the fan wheel. Currently, screws are used to create a screw connection between the fan wheel (hereinafter also referred to simply as the fan) and the fan motor as the electric fan drive.

[0012] The invention is based on the objective of providing a cooling fan that is improved with regard to simplifying assembly. In particular, a

[0013] 2024561 WO page 3 specifies a cost-saving and component-free mechanical interface between the fan motor and the fan wheel, which is particularly suitable in terms of ease of assembly.

[0014] This problem is solved according to the invention by the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

[0015] The radiator fan is specifically designed and configured for installation in a motor vehicle, for example, for mounting in the engine compartment on a body panel. The radiator fan comprises a fan wheel and an (electrical) fan motor with an external rotor, which is rotatably mounted around a motor shaft and connected to the fan wheel via a mechanical interface. The fan wheel has a cup-shaped hub housing with a base. The external rotor of the fan motor also has a cup-shaped rotor housing with a base. In the assembled state, the rotor housing of the fan motor sits within the hub housing of the fan wheel and is secured to it by a number of snap connections.

[0016] Advantageously, a number of spring hooks are axially molded onto the housing base of the hub housing, extending axially with respect to the motor shaft. The spring hooks are suitably arranged in pairs around the motor shaft, particularly evenly spaced. In an advantageous embodiment, a first number of spring hooks have outwardly or oppositely directed detent or snap hooks, and / or a second number of spring hooks have inwardly or mutually directed detent or snap hooks.

[0017] A suitable embodiment provides for a number of joining contours distributed around the motor shaft on the base of the rotor housing. These joining contours are expediently designed as joining or detent openings and / or joining or detent edges that correspond to the spring hooks and are engaged by them in the snap connections.

[0018] 2024561 WO page 4. The detent openings and detent edges are particularly advantageously formed in or on spoke-like radial struts of the housing base of the rotor housing. The radial struts are arranged around the motor axis (axis of rotation), in particular evenly, and are designed to create the snap connections.

[0019] Particularly advantageous is the fact that, in the assembled state, a first set of spring hooks on the hub housing engage in pairs with corresponding insertion openings (locking openings) on the rotor housing. Conveniently, in the assembled state, a second set of spring hooks on the hub housing engages in pairs with radial struts on the rotor housing. The snap connections are particularly advantageous when made with both pairs of spring hooks that compress and pairs that extend. Due to the spring hooks extending axially from the housing base of the fan wheel hub, they form a self-supporting snap connection with the rotor housing at the mechanical interface.

[0020] According to a practical embodiment, the rotor housing is mechanically preloaded axially and / or radially during assembly and when the snap connections are formed and inserted into the hub housing. For axial preloading in particular, a number of axially raised preloading elements are suitably formed on the housing base of the hub housing and arranged, preferably evenly, around the motor axis. In the assembled state, these preloading elements, which are preferably elastically deformable, bear axially preloaded against the outer surface of the rotor housing base of the external rotor.

[0021] To absorb radial forces from the fan motor, a number of axially raised pins are molded onto the base of the hub housing. These pins are preferably conical and elastically deformable. For this purpose, the pins are expediently slotted axially. These pins, which are suitably arranged around the motor axis, particularly evenly spaced, engage in corresponding positions during assembly.

[0022] 2024561 WOPage 5 rende plug openings in the housing base of the rotor housing to absorb operating-related radial forces from the fan motor (fan drive).

[0023] A suitable embodiment provides that a hub cylinder with centering ribs arranged on the outside of the cylinder is provided in the housing base of the fan wheel hub housing. In the assembled state, the axially raised hub cylinder of the hub housing sits in a central opening of the housing base of the rotor housing, with the centering ribs serving as compensating elements, in particular for manufacturing tolerances.

[0024] The advantages achieved with the invention lie particularly in the fact that a screwless mechanical interface for connecting the fan wheel to the fan motor or fan drive is created by means of the preferably cantilevered snap connections. The fan wheel preferably has twelve cantilevered snap connections with three preload elements at the housing base. These enable a suitable and constant axial contact between the fan wheel and the rotor housing of the fan motor and expediently compensate for tolerances, especially plastic tolerances of the fan wheel or its hub housing. In particular, assembly is possible in only one direction, and disassembly is also possible.

[0025] Advantageously, the spring hooks and their free-end locking elements (locking hooks) are positioned evenly around the motor axis (axis of rotation) and have the same (axial) height and angles. This ensures a uniformly distributed reaction force during assembly. Six centering ribs are conveniently provided on the hub cylinder of the fan wheel as a compensating function.

[0026] The suitably at least one radially deformable pin of the fan wheel enables constant radial contact during assembly and serves to transmit forces or loads from the fan motor (drive) to the fan wheel. Preferably, three (3) deformable pins are distributed around the motor axis (axis of rotation) at angles of 120° to each other.

[0027] 2024561 WO page 6. This ensures particularly reliable compensation of tolerances and achieves constant radial contact between the fan wheel and the fan motor (drive), minimizing the possibility of rattling noises.

[0028] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. The drawing shows:

[0029] Fig. 1 shows an exploded view of a radiator fan with an electric fan motor as an external rotor and with a fan wheel with a hub housing and fan blades molded onto it; Fig. 2 shows a perspective view partially of the fan wheel looking into the hub housing at its housing base with detent and preload elements molded onto it.

[0030] Fig. 3 shows a section III from Figure 2 with two spring-loaded spring hooks as a spring hook pair,

[0031] Fig. 4 shows a section IV from Figure 2 with a pair of spring hooks consisting of two retractable spring hooks and a preload element; Fig. 5 shows a representation according to Figure 2 of a rotor housing of the fan motor joined to the hub housing of the fan wheel by means of snap connections.

[0032] Fig. 6 shows a section VI from Figure 5 with spring hooks of the hub housing rusted in a detent opening of the rotor housing,

[0033] Fig. 7 shows a detail VII from Figure 5 with spring hooks of the hub housing rusted onto a radial strut of the rotor housing; Fig. 8 shows a sectional view along line VIII-III in Figure 7, showing the preload element resting against the rusted radial strut; Fig. 9 shows a view according to Figure 2, showing the fan wheel with elastically deformable plug pins on the housing base of the hub housing; Fig. 10 shows a detail X from Figure 9 with a slotted plug pin; Fig. 11 shows a view according to Figure 10, showing the plug pin in a plug opening of a radial strut of the rotor housing.

[0034] Fig. 12 shows a sectional view along the line X1-X1 in Figure 11,

[0035] 2024561 WO Page 7 Fig. 13 in a perspective view a hub cylinder of the hub housing with outer centering ribs, and

[0036] Fig. 14 in a representation according to Figure 13 shows the hub cylinder of the hub housing in a corresponding centering opening of the transparently shown housing base of the mounted rotor housing.

[0037] Corresponding parts are marked with the same reference symbols in all figures.

[0038] Figure 1 shows a radiator fan 1, designed and configured specifically for installation in a motor vehicle, for example, for mounting in the engine compartment on a body panel. The radiator fan 1 has a fan wheel 2 and an (electric) fan motor 3 connected or connectable to it via a mechanical interface. The fan wheel 2 has a cup-shaped hub housing 4 with a (hub-side) housing base 5 and a cylindrical (hub-side) housing wall 6. A number of backward-curved fan blades 7, nine (9) in the exemplary embodiment, are integrally formed on the outside of the housing wall 6. The fan blades 7, of which only one is designated, are connected at their blade ends to an outer ring 8.

[0039] The fan motor or fan drive 3 has a stator 9 with an unspecified stator winding and an external rotor 10, which is rotatably arranged about a motor axis (axis of rotation) D. The fan motor 3 has unspecified motor electronics, which are connected to the vehicle's electrical system via a connecting cable 11. The external rotor 10 of the fan motor 3 has a pot-shaped rotor housing 12 with a (rotor-side) housing base 13 and a cylindrical (rotor-side) housing wall 14, to which a number of permanent magnets 15 are attached on the inside.

[0040] With reference also to figures 2 to 4, a number of first spring hooks 16 and a number of

[0041] 2024561 WO Page 8 of the second spring hooks 17 are formed axially raised relative to the motor or rotation axis. The first spring hooks 16, which thus project axially upwards from the housing base 5 of the hub housing 4 of the fan wheel 2 in the direction of the fan motor 3 or its external rotor 10, are arranged in pairs. Similarly, the second spring hooks 17, which project axially upwards from the housing base 5 of the hub housing 4 of the fan wheel 2 in the direction of the fan motor 3 or its external rotor 10, are arranged in pairs. In the exemplary embodiment, three (3) pairs of hooks of the first spring hooks 16 and three (3) pairs of hooks of the second spring hooks 17 are evenly distributed around the motor axis D and arranged alternately.

[0042] The first spring hooks 16 have detent or snap hooks 16a pointing outwards or in opposite directions. The first spring hooks 16 are spring-elastic and thus resilient, so that the first spring hooks 16 of a hook pair are deformed against each other during the formation of a detent or snap connection with the rotor housing 12 of the fan motor 3.

[0043] The second spring hooks 17 have inwardly or mutually directed detent or snap hooks 17a. These spring hooks 17 are also spring-elastic and thus rebound, so that these pairs of second spring hooks 17 are deformed outwards in the opposite direction during the manufacture of the detent or snap connection with the rotor housing 12 of the fan motor 3. Preload elements 18 are arranged between the second spring hooks 17 of each hook pair, which are axially raised and integrally formed on the housing base 5 of the hub housing 4 and are distributed around the motor axis D.

[0044] Figure 5 shows the assembly state of the rotor housing 12 of the fan motor 3 in the hub housing 4 of the fan wheel 2, looking towards the housing base 13 of the rotor housing 12. The rotor housing 12 of the external rotor 10 is seated in the hub housing 4 of the fan wheel 2 and secured to it by a number of snap connections. A number of radial struts 19, nine in the exemplary embodiment, are attached to the housing base 13 of the rotor housing 12.

[0045] 2024561 WO page 9 provided, which are evenly distributed around the motor axis D and form the joining contours for the spring hooks 16, 17.

[0046] As can be seen from Figures 6 to 8, some of the joining contours arranged on the housing base 13 of the rotor housing 12 are designed as joining or detent openings 20. In the exemplary embodiment, such joining or detent openings 20 are provided in three of the radial struts 19. The first spring hooks 16 correspond to these joining or detent openings 20, which engage the respective opening edges of the joining or detent openings 20 in the corresponding snap connections. Two of the first spring hooks 16 of the hub housing 4 of the fan wheel 2 then engage in the corresponding joining openings (detent openings) 20 of the rotor housing 12.

[0047] Further joining contours arranged on the housing base 13 of the rotor housing 12 are also formed, in the exemplary embodiment, by three of the radial struts 19, starting from the opposing detent edges 21. In the exemplary embodiment, these are adjacent to the radial struts 19 with the joining or detent openings 20 in the circumferential direction, for example, directly. The second spring hooks 17 correspond to these detent edges 21, which engage the corresponding detent edges 21 of the respective radial strut 19 in the corresponding snap connections. In this way, two of the second spring hooks 17 of the hub housing 4 of the fan wheel 2 engage the corresponding detent edges 21 of the rotor housing 12.

[0048] Figure 8 shows one of the preload elements 18, which are axially molded onto the housing base 5 of the hub housing 4. During assembly, when the snap connections are formed, the respective preload element 18 rests against the housing base 13 of the rotor housing 12 of the outrunner rotor 10 on the side facing the hub-side housing base 5. By means of the preloaded preload elements 18, the rotor housing 12 is mechanically preloaded axially and radially when inserted into the hub housing 4 during assembly and when the snap connections are formed.

[0049] 2024561 WO page 10

[0050] Figures 9 to 12 show an embodiment of the fan wheel 2 in which a number of axially raised plug pins 22 are integrally formed on the housing base 5 of the hub housing 4. The plug pins 22, which are preferably conical in shape, are axially slotted and elastically deformable. The plug pins 22, which are arranged evenly distributed around the motor axis D, engage in corresponding plug openings 23 in the housing base 13 of the rotor housing 12 of the external rotor 10 when assembled.

[0051] The radial forces exerted by the fan wheel 2 during operation are absorbed by the fan motor (fan drive) 3 via the connecting pins 22. The radially deformable connecting pins 22 of the fan wheel 2 ensure constant radial contact during assembly and transmit forces or loads from the fan motor (drive) 3 to the fan wheel 2. Furthermore, tolerances are compensated for, and constant radial contact between the fan wheel 2 and the fan motor (drive) 3 is achieved. Additionally, rattling noises can be minimized.

[0052] As can be seen relatively clearly in Figures 13 and 14, a hub cylinder 23 is provided in the housing base 5 of the hub housing 4 of the fan wheel 2. A number of centering ribs 25 are arranged or integrally formed on the outside of this cylinder. In the assembled state, the hub cylinder 23 engages in a central opening 26 of the housing base 13 of the rotor housing 12. The six (6) centering ribs 25, for example, serve as compensating elements.

[0053] In summary, the invention relates to a cooling fan 1, comprising a fan wheel 2 and a fan motor 3, which is connected to a cup-shaped hub housing 4 of the fan wheel 2, wherein the fan motor 3 has a rotatably arranged external rotor 10 with a cup-shaped rotor housing 12, which is seated in the hub housing 4 of the fan wheel 2 and is connected to it by a number of snap connections.

[0054] 2024561 WO Page 11 The claimed invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived by a person skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention, for example, its use in hybrid or electric vehicles. In particular, all individual features described in connection with the various embodiments can also be combined in other ways within the scope of the disclosed claims without departing from the subject matter of the claimed invention. Page 12

[0055] Reference symbol list

[0056] 1 cooling fan

[0057] 2 fan wheels

[0058] 3 fan motor Z-drive

[0059] 4 hub shells

[0060] 5 Hub-side housing base 6 Hub-side housing wall 7 Fan blade

[0061] 8 Outer ring

[0062] 9 Stator

[0063] 10 Outrunner rotor

[0064] 11 connection cables

[0065] 12 rotor housings

[0066] 13 Rotor-side housing base 14 Rotor-side housing wall 15 Permanent magnet

[0067] 16 first spring hook

[0068] 16a Rast-Z Snap hook

[0069] 17 second spring hook

[0070] 17a Rast-Z Snap hook

[0071] 18 Preload element

[0072] 19 radial strut

[0073] 20 Joining-Z-Gap Opening

[0074] 21 Joining edge

[0075] 22 Plug pin

[0076] 23 Plug opening

[0077] 24 hub cylinders

[0078] 25 centering rib

[0079] 26 central opening

[0080] D Motor-Z rotary axis

[0081] 2024561 WO

Claims

Page 13 Claims 1. Radiator fan (1), in particular of a motor vehicle, comprising a fan wheel (2) and a fan motor (3) which is connected to or mountable in a cup-shaped hub housing (4) of the fan wheel (2) having a housing base (5), wherein the fan motor (3) has an external rotor (10) rotatably arranged about a motor axis (D) with a cup-shaped rotor housing (12) having a housing base (13), which is seated in the hub housing (4) of the fan wheel (2) and is connected to it by a number of snap connections.

2. Cooling fan (1) according to claim 1 , characterized by that a number of spring hooks (16, 17) arranged distributed around the motor shank (D) are axially raised on the housing base (5) of the hub housing (4).

3. Cooling fan (1) according to claim 1 or 2, characterized by that a number of joining contours (20, 21) are provided on the housing base (13) of the rotor housing (12) distributed around the motor shaft (D).

4. Cooling fan (1) according to one of claims 1 to 3, characterized by that a number of axially raised preload elements (18) are formed on the housing base (5) of the hub housing (4), distributed around the motor shaft (D), which in the assembly state bear axially preloaded against the housing base (13) of the rotor housing (12) of the outer rotor (10). 2024561 WO Page 14 5. Cooling fan (1) according to one of claims 1 to 4, characterized by that the housing base (13) of the rotor housing (12) has a number of radial struts (19) arranged around the motor axis (D) for making snap connections.

6. Cooling fan (1) according to one of claims 1 to 5, characterized by that a number of axially raised plug pins (22) are formed on the housing base (5) of the hub housing (4), distributed around the motor axis (D), which engage in corresponding plug openings (23) in the housing base (13) of the rotor housing (12) when assembled.

7. Cooling fan (1) according to claim 6, characterized by that the plug pins (22) are conical and / or elastically deformable.

8. Cooling fan (1) according to one of the preceding claims, characterized by that in the housing base (5) of the hub housing (4) a hub cylinder (24) is provided which in the assembly state is seated in a central opening (26) of the housing base (13) of the rotor housing (12) with centering ribs (25) arranged on the outside of the cylinder.

9. Cooling fan (1) according to one of the preceding claims, characterized by that in the assembled state a number of first spring hooks (16) of the hub housing (4) engage in pairs in corresponding joining openings (20) of the rotor housing (12). 2024561 WO Page 15 10. Cooling fan (1) according to one of the preceding claims, characterized by that in the assembled state a number of second spring hooks (17) of the hub housing (4) overlap in pairs a radial strut (19) of the rotor housing (12), in particular locking edges (21) of the radial strut (19). 2024561 WO

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