Miniature fan or micro-fan

Abstract

A miniature fan or micro-fan (200) features a fan housing (150) through which a substantially annular air duct extends in the axial direction, there being arranged in a central region of the air duct an electronically commutated external-rotor motor (202) whose external rotor, equipped with at least one permanent magnet (86), carries an impeller wheel (204) that is arranged rotatably in the air duct. A circuit board configuration (168) has a motor region that is arranged in the central region of the air duct and carries at least one galvanomagnetic rotor position sensor that is controllable by the magnetic field of the permanent magnet (86) provided on the external rotor. The board has a component region for the reception of electronic components (170) of the external-rotor motor, which component region is arranged substantially outside the air duct, and which comprises a bridge portion, via which the motor region of the circuit board configuration is electrically connected to the component region (168).

Description

[0001] This application is a section 371 of PCT / EP02 / 13822, filed 6 DEC. 2002 and published 17 Jul. 2003 as WO 03-058 796-A1.FIELD OF THE INVENTION [0002] The invention relates to a miniature fan or micro-fan that is driven by an electronically commutated external-rotor motor. BACKGROUND [0003] Miniature fans or micro-fans serve, for example, to cool processors in computer, to cool small devices, etc., and they have very small dimensions. For example: [0004] fans of PAPST series 250 have dimensions of 8×25×25 mm, [0005] those of PAPST series 400F, dimensions of 10×40×40 mm, [0006] those of PAPST series 400, 20×40×40 mm, [0007] those of PAPST series 500, 50×50×15 mm, and [0008] those of PAPST series 600, 60×60×25 mm. [0009] The power consumption of such fans is 0.4-0.6 W for series 250, 0.7-0.9 W for series 400F, 0.9-1.6 W for series 400, and 0.8-3.4 W for series 600. This defines the preferred field of application of the present invention. [0010] In fans that are driven by an electr...

AI Technical Summary

Benefits of technology

The invention provides a new miniature fan or micro-fan with a larger annular air flow cross section, which allows for larger fan blades and greater flow rate and pressure increase for the same physical size. The motor region is arranged on the inner side of the air duct, which further increases the flow rate and pressure increase. The invention also allows for more functions to be integrated into the fan, such as PWM open- and closed-loop control systems, analog and digital rotation speed controllers, and programmable rotation speed controllers. This advancement allows for reliable control of the fan via a data bus and meets high standards for electromagnetic compatibility.

Problems solved by technology

In fans that are driven by an electronically commutated external-rotor motor, the motor is large in relation to the overall size of the fan, which is disadvantageous in terms of the flow rate (V / t) and pressure increase Δp of the fan.

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