Ebm-papst St. Georgen Gmbh & Co Kg

Nils Rapp

Wolfgang Arno Winkler

Hansjörg Berroth

A mini-fan has a drive motor having an external rotor () and an internal stator (). The external rotor () is equipped with a rotor shaft () that has a necked down portion () in the region of its free end (). The mini-fan () has a bearing tube () on whose outer side the internal stator () is mounted and in whose interior is arranged a bearing arrangement () in which the rotor shaft () is rotatably supported. A closure arrangement () serves to close off the bearing tube () in liquid-tight fashion at one end, and is equipped, in the region of the necked down portion () of the rotor shaft (), with at least one resilient securing member () that engages into that necked down portion () and secures the rotor shaft () against being pulled out of the bearing arrangement ().

Mini fan

For many applications, it is desirable to use fans which weigh less than 30 grams and are driven by electric motors not more than a few centimeters in size. Mass-producing products this small, which nevertheless must be extremely reliable, poses unique manufacturing challenges, which are best overcome by an improved structure which is susceptible to automation. Preferably, the fan motor is electronically commutated and has an internal stator () and an external rotor () supported on a central rotor shaft (). The shaft is journaled within a bearing tube () supporting first and second rotor bearings (). By injection-molding the bearing tube () with first and second axial extensions (), the extensions can hold the bearings in place and insure uniform manufacturing quality and a desirably long service life. One of the extensions can also be shaped to abut against a circuit board () which supports components which control commutation.

Electronically commutated motor

A mini-fan () is implemented for installation in a recess () of a wall (), which wall is equipped on the periphery of the recess () with a plurality of retaining members (). The fan has, for air guidance, a housing () that, in its installed position, projects with a housing portion () approximately complementary to the recess () of the wall () into that recess. Arranged on the periphery of that housing portion is at least one part () made of an elastomeric material, with which part the fan () is introducible, upon its installation with the part () made of elastomeric material with displacement along the wall (), into the retaining members (), in order to bring that part (), in the installed position, at least locally into sealing contact against the wall ().

Mini fan to be fixed in a recess of a wall

An improved structure and method for mounting a fan, particularly a miniature fan (), in a supporting wall (), both facilitates a mounting operation and minimizes noise conduction after the mounting operation. An elastomeric overcoat () at least partially surrounds the fan () and is preferably integrally formed with a plurality of mushroom-shaped mounting elements () adapted to engage in a corresponding plurality of mounting holes () formed in the supporting wall (). Each mounting element has a shaft portion () and a head portion () with an internal channel () starting in the shaft portion () and ending in the head portion (). Rapid mounting of the fan () to the wall () can be accomplished by inserting a respective tool () into the channel () of each mounting element (), to elongate the mounting element and reduce its diameter, passing the elongated mounting element into its mounting hole (), and withdrawing the tool, permitting elastic relaxation of the mounting element to restore its original diameter, thereby forming a secure, vibration-damping engagement with the periphery of the mounting hole.

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St. Georgen, Germany

Nils Rapp