BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a coolant pumping device for circulating coolant through a computer device, and in particular to a coolant pumping device comprising a sensing element for detecting polarity of a rotor magnet to enhance operation smoothness of the pumping device.
2. The Related Art
A conventional coolant pumping device of the above-mentioned type comprises a rotor magnet rotatably fit over an axle, which is driven by a stator portion comprising windings and silicon steel plates. The rotor magnet in turn drives the rotation of a blade assembly to effect circulation of coolant.
The conventional coolant pumping device suffers a drawback that when the magnetic poles of the magnet are exactly opposite to the magnetic poles of the magnetic field induced by the windings, the rotor magnet becomes stationary and starting rotation of the rotor in such a condition is difficult for the magnet is attracted by the magnetic field of the windings and no repulsive force is induced between the magnet and the windings. Starting the rotation of the rotor under such a condition is difficult, and high level of noise can be generated. This in turn stops the circulation of the coolant through a computer device with which the pumping device is combined for cooling heat-generating elements or components of the computer device. As a result, over-heating of the computer device may occur and failure of the operation of the computer device results.
- SUMMARY OF THE INVENTION
Thus, it is desired to have a coolant pumping device that overcomes the problem of starting as discussed above.
An object of the present invention is to provide a coolant pumping device that effectively overcomes the problem of starting occurring in the conventional designs and enhances the operation smoothness of the pumping device thereby improving heat removal efficiency.
Another object of the present invention is to provide a coolant pumping device comprising a sensing element for detecting the polarity of a rotor magnet in order to enhance the operation smoothness of the pumping device.
BRIEF DESCRIPTION OF THE DRAWINGS
To achieve the above objects, in accordance with the present invention, there is provided a coolant pumping device, particularly suitable for liquid based cooling operation of computer devices, comprising a casing containing a stator portion of an electrical motor, comprising windings and silicon steel plates, and a control circuit board. A first chamber is formed atop the casing in which a blade assembly is rotatably received for effecting circulation of a coolant. A second chamber delimited by a cylindrical wall fixed inside the casing rotatably receives a rotor magnet, which is driven by the stator portion. The blade assembly/is fixed to the rotor magnet. Slots are defined in the casing for retaining the control circuit board. A Hall IC, serving as a sensing element for detecting polarity of the magnet inside the second chamber is electrically connected to the circuit board and is fixed inside the casing. The sensing element provides a detection signal to the control circuit board to enhance operation smoothness of the pumping device.
The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which:
FIG. 1 is a perspective view of a coolant pumping device constructed in accordance with the present invention;
FIG. 2 is an exploded view of the coolant pumping device of the present invention;
FIG. 3 is a cross-sectional view of the pumping device of the present invention;
FIG. 4 is a perspective view showing a casing of the coolant pumping device in an up-side-down manner to illustrate inside details thereof; and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 5 is a bottom view of the casing of the coolant pumping device of the present invention.
With reference to the drawings and in particular to FIGS. 1 and 2, which show, respectively, a perspective view and an exploded view of a coolant pumping device constructed in accordance with the present invention, generally designated with reference numeral 10, the coolant pumping device 10 comprises a casing 11 defining an interior space (not labeled) in which parts constituting a stator portion of an electrical motor are arranged, including at least windings 30 and silicon steel plates 31. A circuit board 40 on which a circuit for controlling power supplied to the stator portion is formed is also arranged inside the casing 10 and in electrical connection with the stator portion.
A first chamber 12 is formed atop the casing 11. In the embodiment illustrated, the first chamber 12 comprises a cylindrical outer wall from which a coolant outlet 18, which in the embodiment illustrated is in the form of a shaped tube in fluid communication with the first chamber 12, extends. A lid 17 closes a top opening (not labeled) of the first chamber 12, preferably in a removable manner. A coolant inlet 16, also in the form of a tube, is formed on the lid 17 and in fluid communication with the first chamber 12. A second chamber 19 (FIGS. 4 and 5), in communication with the first chamber 12, is delimited by a cylindrical wall extending into the interior of the casing 11 and partly surrounded by the silicon steel plates 31 of the stator portion. A fixed axle 13 is concentrically formed in and co-extends along the second chamber 19 with a top end extending into the first chamber 12.
Also referring to FIG. 3, a magnet 14 is received in the second chamber 19 and is rotatably fit over the axle 13 to serve as a rotor of the motor. A blade assembly, 15 is arranged inside the first chamber 12 and rotatably fit over the top end of the axle 13 and fixed to the magnet 14 to rotate in unison with the magnet 14. Thus, when power is supplied to the windings 30, a magnetic field is induced on the magnet 14 by the steel plates 31, which drives the rotation of the magnet 14 and the blade assembly 15. The rotation of the blade assembly 15 inside the first chamber 12 draws coolant from the inlet tube 16 into the first chamber 12 and drives the coolant out of the first chamber 12 through the outlet tube 18 to effect circulation of the coolant.
Also referring to FIGS. 4 and 5, which show an up-side-down perspective view and a bottom view of the casing 11 of the coolant pumping device 10 of the present invention, respectively, a first retention slot 20 is formed on an outside surface of the cylindrical wall of the second chamber 19. Also, second retention slots 21 are formed on opposite inside surfaces of the casing 11 to respectively receive opposite edges of the circuit board 40, thereby retaining the circuit board 40 inside the casing 11. A sensing element 41, which is electrically connected to and spatially extending from the circuit board 40 (also see FIG. 2), is received and retained in the first retention slot 20, whereby the sensing element 41 is located at a position corresponding to the magnet 14 inside the second chamber 19.
The sensing element 41 detects the polarity of the rotor magnet 14 and provides control signal to the control circuit of the circuit board 40, which changes the magnetic field induced by the windings 30 to enhance drivability of the rotor 14. For example, when the magnet 14 is at such an angular position where the north pole of the magnet 14 opposes the sensing element 41 and where the rotor magnet 14 cannot be driven into rotation smoothly, the sensing element 41 reverses the magnetic field in short period of time to drive the rotor 14 easily. This effectively solves the problem of undesired problems, such as delay and severe vibration, in starting the rotation of the rotor that often encountered in the prior art devices.
Any known sensing element 41 can be used in the coolant pumping device 10 of the present invention provided such a sensing element 41 functions as described above. An example of the sensing element 41 comprises a Hall IC, which detects the polarity of the magnet 14 and provides desired control signals to the circuit board 40.
To this end, it is obvious that the, present invention has a simple construction, which is not much more complicated than the conventional devices, while effective in enhancing smoothness of rotation starting of the rotor. The cooling efficiency of the coolant pumping device of the present invention can thus be improved over the conventional devices, which is particularly of interest in the applications of heat dissipation for high efficiency computer systems. Computer systems with such a coolant pumping device can be operated more smoothly without undesired failure caused by over-heating.
Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.