TREA

Fan wheel and electric motor

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Information

  • Patent Application
  • 20080095626
  • Publication Number
    20080095626
  • Date Filed
    October 20, 2006
    18 years ago
  • Date Published
    April 24, 2008
    16 years ago
Information
Abstract
This present invention relates to a fan wheel for an electric motor which fan wheel comprises fan vanes and a cylindrically arranged hub wherein said hub consists of a rigid fixing section for attachment to a drive shaft of the electric motor on the one hand and of a flexible section axially extending from said fixing section on the other hand and wherein the fan vanes are allocated to the flexible section.
Description

An exemplary embodiment of the present invention will now be explained with reference to the drawings in which:



FIG. 1 is a side view of a circulation pump;



FIG. 2 is a longitudinal section through a fan wheel which is attached to the drive shaft of an electric motor; and



FIG. 3 is a larger-scale view of a detail X in FIG. 2.





A fan wheel 1 of this present invention may be employed for circulation pump systems of the type used in domestic appliances or in industrial production facilities.



FIG. 1 shows a synchronous circulation pump for evaporation coolers comprising an electric motor 2 with a drive shaft 3 for the fan wheel 1 to be mounted on.


The fan wheel 1 comprises a number of radially curved spokes 5 which extend from a hub 4 and which are each adjoined by fan vanes 6.


The hub 4 is provided in form of a hollow cylinder and composed of a rigid fixing section 7 and a flexible section 8 offset in axial direction. The flexible section 8 comprising the spokes 5 and the fan vanes 6 is disposed in a first axial portion A1 and the fixing section is arranged in a second axial portion A2 adjacent thereto. The flexible section 8 is integrally formed with the spokes and the fan vanes 6, respectively, and extends in a substantially common radial plane R.


The fixing section 7 of the hub 4 is made of a rigid/strong plastic material, preferably propylene, and secured to the drive shaft 3 in a press-fit mode.


The flexible section 8 of the hub together with the spokes 5 and the fan vanes 6 of the fan wheel 1 is formed of a flexible (oscillation damping) plastic material, preferably a thermoplastic elastomer.


The fixing section 7 of the hub 4 is provided in form of a cylindrical sleeve which is positively and/or integrally and/or frictionally fitted on the drive shaft 3. The shell surface of the fixing section 7 consists of a main portion 7′ and a reduced end portion 7″ which portions are in contact with the drive shaft 3 by their inside faces. The reduced end portion 7″ of the sleeve is integrally connected to an annular portion 8′ of the flexible section 8. Said annular portion 8′ of the flexible section 8 is injection molded to the end portion 7″ of the sleeve 7.


The fan wheel 1 is preferably produced by a two-component injection molding process comprising the steps of charging into a mold the plastic material mass to provide the sleeve 7 first and the plastic material mass to provide the flexible section 8 thereafter.


As will be seen more clearly from FIG. 3, an inside diameter d1 of the flexible section 8 is larger than an inside diameter d2 of the sleeve 7 and/or the outside diameter d2 of the drive shaft 3. This way there is always an annular gap S between the flexible section 8 and the drive shaft 3 within the first axial portion A1. This separation of the fan wheel 1 from the drive shaft 3 permits to substantially damp or reduce the action of interfering pendulum oscillations.


The wall thickness of the end portion 711 of the sleeve 7 and that of the annular portion 81 of the flexible section 8 is selected such that the main portion 71 of the sleeve 7 and the flexible section 8′ have the same outside diameter dM or dE, respectively. This implies that the hub 4 has a continuous cylindrical outer surface extending along the first axial portion A1 and the second axial portion A2.


The annular portion 8′ of the flexible section 8 preferably has an inner annular groove 9 whose length 1N predetermines the length of the reduced end portion 7″ of the sleeve 7. This permits to improve on the adhesive force in the junction areas between the sleeve 7 and the flexible section 8.


According to a not-shown embodiment of the present invention it is also possible to provide the fan wheel 1 with a fan rim to which the fan vanes are attached. The spokes are connected to said fan rim in that embodiment.

Claims
  • 1. Fan wheel for an electric motor comprising fan vanes and a cylindrically arranged hub, characterized by the fact that the hub (4) has a rigid fixing section (7) for attachment to the drive shaft (3) of an electric motor (2) on the one hand and a flexible section (8) in axial extension of said fixing section (7) on the other hand, said fan vanes (6) being disposed within said flexible section (8).
  • 2. Fan wheel as set forth in claim 1, characterized by the fact that the flexible section (8) of the hub (4) is integrally connected to the fixing section (7) thereof.
  • 3. Fan wheel as set forth in claim 1, characterized by the fact that the flexible section (8) of the hub (4) is injection molded to the fixing section (7) thereof.
  • 4. Fan wheel as set forth in claim 1, characterized by the fact that the hub (4) is produced by two-component injection molding wherein the fixing section (7) is formed of a propylene material and the flexible section (8) of an elastomeric material.
  • 5. Fan wheel as set forth in claim 1, characterized by the fact that the fixing section (7) is provided in form of a cylindrical sleeve which is adapted to be positively and/or integrally and/or frictionally connected to the drive shaft (3) by one of its shell surfaces.
  • 6. Fan wheel as set forth in claim 1, characterized by the fact that the sleeve (7) comprises a main portion (7′) and a reduced end portion (7″) wherein an annular portion (8′) of the flexible section (8) extends from an outside surface of the end portion (7″).
  • 7. Fan wheel as set forth in claim 1, characterized by the fact that the inside diameter (d1) of the flexible section (8) is larger than the inside diameter (d2) of the sleeve (7) or larger than the outside diameter (d2) of the drive shaft (3), respectively.
  • 8. Fan wheel as set forth in claim 1, characterized by the fact that the annular portion (8′) of the flexible section (8) and the main portion (7′) of the sleeve (7) have the same outside diameter (dM, dE).
  • 9. Fan wheel as set forth in claim 1, characterized by the fact that the flexible section comprises within the annular portion (8′) an inner annular groove (9) for the reduced end portion (7″) of the sleeve to extend in.
  • 10. Fan wheel as set forth in claim 1, characterized by the fact that the length (1N) of the annular groove (9) corresponds to the length of the end portion (7″) of the sleeve (7).
  • 11. Fan wheel as set forth in claim 1, characterized by the fact that the fan vanes (6) and/or the fan spokes (5) and/or a fan rim are arranged to extend within a first axial portion (A1) of the fan wheel (1) on the one hand and that the fixing section (7) of the hub (4) extends within a second axial portion (A2) of said fan wheel (1) on the other hand.
  • 12. Electric motor for a pump which motor comprises a fan wheel mounted on a drive shaft as set forth in claim 1.