Abstract:
A turbine includes a top cover, a bottom cover and fans between the top cover and the bottom cover. The fans extend to connect the central shaft and do not overlap with each other in the axial direction. The air sucked in through the central air inlet can swiftly flow along the fans and then be expelled out of the turbine through the circumferential air outlets. Compared with the conventional centrifugal fan, the disclosed turbine can effectively increase the air draft efficiency of the turbine. Compared with the standard turbine, the disclosed turbine is simpler and easier to process, and thus the cost can be significantly reduced.

Description:
[0001]    This application claims the benefit of Taiwan Patent Application Serial No. 103139620, filed Nov. 14, 2014, the subject matter of which is incorporated herein by reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a fan structure, and more particularly to a turbine structure. 
         [0004]    2. Description of the Prior Art 
         [0005]    The vacuum is an appliance that uses a motor to rotate an intake fan so as to generate a vacuum pressure for dedusting. While in operating the vacuum, the dust won&#39;t be further sprayed, and the dust in some difficult corners such as in the carpet or in a narrow crack can be easily removed. Thus, the vacuum featured in convenience and cleaning capability is widely used domestically and in public facilities. 
         [0006]    The intake fan of the vacuum is usually formed as a centrifugal impeller structure or a turbine structure. The centrifugal impeller structure adopts a centrifugal fan to act as the intake fan for the vacuum. The popular centrifugal fan, featured in simple structuring and easy manufacturing, is usually made of plastics, and is adequately manufactured by a plastic molding process. However, the air draft efficiency of the turbine at the air outlet of the plastic-made centrifugal fan is seldom to meet the requirement. Especially, while being used in a portable form energized by batteries, the energy required for operating the vacuum to meet a satisfied air draft efficiency of the turbine at the air outlet would be higher than expected. Though the air draft efficiency of the conventional turbine at the air outlet is higher than that of the centrifugal fan, yet the complicate structuring and the difficult manufacturing for the turbine has prevented it from popularity, especially in pricing. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, it is the primary object of the present invention to provide a turbine with high air draft efficiency at the air outlet, simple structuring and easy machining. 
         [0008]    In the present invention, the turbine includes a central shaft, a top cover, a bottom cover, an air inlet, a plurality of air outlets and a plurality of fans mounted between the top cover and the bottom cover. The air inlet is formed as a hole at a center portion of the top cover. The air outlets to circle along a circumference of a casing formed by matching the top cover and the bottom cover. The fans are mounted inside the casing, and each of the fans originates at the central shaft and extends therefrom outward. In the present invention, individual projections of the fans formed along the central shaft are not overlapped. 
         [0009]    In one embodiment of the present invention, each of the fans further includes a curved protrusion extending toward the air inlet in a rotational direction. 
         [0010]    In one embodiment of the present invention, the curved protrusion is located within the air inlet. 
         [0011]    In one embodiment of the present invention, the turbine further includes a plurality of auxiliary fans, each of the auxiliary fans has a frontal area smaller than that of the fans, and the auxiliary fans and the fans are arranged at intervals. 
         [0012]    In one embodiment of the present invention, one inner end of the auxiliary fan is close but not touching the central shaft, and an outer end thereof is flush with an outer rim of the bottom cover, wherein the auxiliary fan is to divide an arc length between two said neighboring fans by a ratio ranged from 1:2 to 1:1 along a counter clockwise direction. 
         [0013]    In one embodiment of the present invention, the inner end of the auxiliary fan is located within the axial projection of the air inlet. 
         [0014]    In one embodiment of the present invention, the number of the fans is equal to that of the auxiliary fans, and the number is one of 3, 4 and 5. 
         [0015]    In one embodiment of the present invention, the fan is originated at the central shaft and extends outward to have one end thereof flush with an outer rim of the bottom cover, and wherein the fans, the top cover, the bottom cover and the central shaft are together to form a plurality of chambers inside the turbine. 
         [0016]    In one embodiment of the present invention, the bottom cover further includes a central protrusion connected with the central shaft, and a concave portion is formed as a part of the bottom cover extended from the central protrusion to a lower outer end of the bottom cover. 
         [0017]    In one embodiment of the present invention, the turbine is a product of molding. 
         [0018]    In the present invention, the top cover, the bottom cover and the fans sandwiched between the top cover and the bottom cover are all arc-shaped. The fan further includes the curved protrusion disposed at a position respective to the air inlet and extending in the rotational direction. Upon such an arrangement, when the foreign air is sucked into the turbine through the air inlet, the sucked-in air can be swiftly guided to pass the curved protrusions and the channels walled by the fans and the auxiliary fans, and to flow out of the turbine via the circumferential air outlets. By compared to the conventional centrifugal fans, the turbine provided by the present invention can substantially increase the air draft efficiency, and, by compared to a typical turbine, the turbine of the present invention is superior in simple structuring, easy machining and a reduced manufacturing cost. 
         [0019]    All these objects are achieved by the turbine described below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which: 
           [0021]      FIG. 1  is a schematic perspective view of the preferred turbine in accordance with the present invention; 
           [0022]      FIG. 2  is another state of  FIG. 1  by removing the top cover; 
           [0023]      FIG. 3  is a cross sectional view of  FIG. 1 ; and 
           [0024]      FIG. 4  is a top view of  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    The invention disclosed herein is directed to a turbine. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention. 
         [0026]    Referring now to  FIG. 1  and  FIG. 2 , the turbine  100  of the present invention includes a top cover  110 , a bottom cover  120 , a plurality of fans  130  mounted between the top cover  110  and the bottom cover  120  and a central shaft  140 . The central shaft  140  is the origin of all fans  130  and can be seen as the center line of the turbine  100 . The top cover  110  further has an air inlet  111  located at a central portion thereof. A casing formed between the top cover  110  and the bottom cover  120  is to accommodate the fans  130 . The air outlets  150  are thus located to the outer ends of the fans  130  in a manner of circling along a circumference of the top cover  110  and the bottom cover  120  (i.e. the circumference of the casing). Each of the fans  130  is originated at the central shaft  140  and extended outward. An curved protrusion  133  is extended along a rotational direction from a portion of the fan  130  at a position respective to the air inlet  111 , such that the intake air entering the turbine  100  can be guided by the curved protrusion  133  to further smoothly flow out of the turbine  100  from the circumferential air outlet  150 . Upon such an arrangement, the air flow efficiency can be increased. Namely, the air draft efficiency of the turbine  100  at the air outlets  150  can be substantially increased. While in operation, a motor engages and drives the turbine  100  to rotate. Foreign air is sucked into the turbine  100  through the air intake  111  by the vacuum pressure generated by rotating the fans  130 . The intake air (used to be the foreign air) is then expelled out of the turbine  100  through the air outlet  150 . By compared to the conventional centrifugal fan, the air draft efficiency of the turbine  100  at the air outlet  150  in accordance with the present invention is higher. Further, by compared to the conventional turbine structure, the turbine of the present invention is superior in simple structuring, easy machining and a reduced manufacturing cost. 
         [0027]    Referring now to  FIG. 2  and  FIG. 3 , the central shaft  140  of the present invention is to engage the motor, and thereby the power of the motor can be transmitted to rotate the turbine  100  via the central shaft  140 . As shown, the fans  130  are arranged separately on the bottom cover, and each of the fans  130  is arc-shaped and has one end connected with the central shaft  140  and another end flush with the circumference of the bottom cover  120 . Upon such an arrangement of the top cover  110 , the bottom cover  120  and the fans  130 , a series of the air outlets  150  can be formed along the circumference of the turbine  100 . Walled by the fans  130 , the top cover  110 , the bottom cover  120  and the central shaft  140 , the interior space of the turbine  100  is divided into a plurality of small radial chambers, and the number of the small chambers is equal to the number of the fans  130 . It is noted that, in the present invention, the fans  130 , the top cover  110 , the bottom cover  120  and the central shaft  140  are all fixed in related positions. The curved protrusion  133  of the fan  130 , with respect to the air inlet  111  is extended in the rotational direction of the turbine  100 , and individual projections of the fans  130  produced along the axial direction (onto a surface perpendicular to the axial direction) are not overlapped. The protrusive curved protrusion  133  is extended within the range of the air inlet  111 , but not necessary to be flush with the rim of the air inlet  111 . Upon such an arrangement, when the foreign air is sucked into the turbine  100 , the flow of the intake air (used to be the foreign air) is guided by the respective curved protrusion  133 . For the projections of individual fans  130  in the axial direction are not overlapped, the flow resistance inside the turbine  100  for the sucked-in foreign air is low, and thus the speed of the interior flow of the turbine  100  can be increased. As a sequence, the air draft efficiency of the turbine  100  at the air outlets  150  is increased as well. In the embodiment as shown, the turbine  100  includes four fans  130 , while, in other embodiments, the number of the fans  130  may be 3, 5 or any number relevant to the instant device. 
         [0028]    Referring now to  FIG. 2 ,  FIG. 3  and  FIG. 4 , preferably, the turbine  100  can further includes a plurality of auxiliary fans  131 , each of which has a frontal area smaller than that of the fan  130 . The auxiliary fans  131  and the fans  130  are spaced at intervals. One end of the auxiliary fan  131  is flush with the outer rim of the bottom cover  120 , while another end thereof is located within the range of the air inlet  111  in a projection sense in the axial direction. Namely, an individual auxiliary fan  131  is disposed between two neighboring fans  130 . By providing the auxiliary fan  131 , each of the air outlet  150  formed by the fans  130 , the top cover  110  and the bottom cover  120  is further divided into two small air outlets  150 . Structuring of each auxiliary fan  131  can be resembled to that of the fan  130  without the curved protrusion  133 . The auxiliary fan  131  is shorter than the fan  130 . As a top view from the top cover  110  ( FIG. 4 ), the inner ends of the auxiliary fans  131  (the ends close to, but not touching, the central shaft  140 ) can be observed through the air inlet  111 . Namely, the inner ends of the auxiliary fans  131  are fallen within the axial projection range of the air inlet  111 , without touching the central shaft  140 . Thereby, as the foreign air is sucked into the turbine  100  through the air inlet  111 , the air is turned firstly by the extending curved surfaces  133 , and then bifurcated to two small channels formed by the two neighboring fans  130  and one middle auxiliary fan  131 . The bifurcated flow is then to leave the turbine  100  via the respective air outlet  150  located at the outer ends of the corresponding fans  130  and auxiliary fan  131 . Through such a design of the turbine  100 , both the internal draft efficiency and the expelling efficiency of the turbine  100  with respect to the foreign air can be substantially enhanced. In the present invention, the number of the auxiliary fans  131  is determined by the number of the fans  130 . In the preferred embodiment as shown, for the fans  130  and the auxiliary fans  131  are spaced at intervals, the number of the auxiliary fans  131  is equal to the number of the fans  130 . As shown, the preferred embodiment has four fans  130  and four auxiliary fans  131 , while, in other embodiments, the aforesaid number might be varied per instant requirement. 
         [0029]    As shown, the outer ends of the fans  130  and the auxiliary fans  131  are all flush with the outer rim of the bottom cover  120 . Further, for the fans  130  and the auxiliary fans  131  are arranged at intervals, each of the auxiliary fans  131  is inevitable to divide the arc length of the outer rim of the bottom cover  120  between two neighboring fans  130 . In one embodiment, the aforesaid arc length can be cut into a 4:5 ratio in a counter clockwise direction, while, in other embodiments, the ratio can be 1:2, 1:1 or any relevant ratio. Namely, the exact position of each auxiliary fan  131  between the two neighboring fans  130  is not a fixed parameter in design. Preferably, the auxiliary fan  131  is to divide the arc length between two neighboring fans  130  by a ratio ranged from 1:2 to 1:1 along the counter clockwise direction. 
         [0030]    As shown, the curved protrusion  133  protruded from the respective fan  130  is located within the range of the air inlet  111 . Namely, each of the fans  130  protrudes toward the air inlet  111  by the curved protrusion  133  falling within the axial projection of the air inlet  111 . The curved protrusion  133  is not necessary to be flush with the air inlet  111 . However, for the curved protrusion  133  is protruded upwards over other portions of the fan  130  and the auxiliary fan  131 , so the central portion of the top cover  110  is also hill up to form the air inlet  111  on top so as ensure that the curved protrusion  133  can be contained and fallen within the axial projection of the air inlet  111 . 
         [0031]    As shown in  FIG. 3 , the bottom cover  120  further includes a central protrusion  121  connected with the central shaft  140 , and a concave portion  122  is formed as a part of the bottom cover  120  extended from the central protrusion  121  to the lower outer end of the bottom cover  120 . The curvature of the concave portion  122  is not necessary a design factor, but shall meet to be smoothly connected with other portions of the bottom cover  120 . In order to ensure a tight contact between the fans  130  and the bottom cover  120 , the lower surface of the fan  130  facing the bottom cover  120  can be formed to be a convex surface  134  to match the concave portion  122  of the bottom cover  120 . 
         [0032]    Preferably, the fans  130  are fixed on the bottom cover  120 , and the top cover  110  are also fixedly connected with the fans  130 . In the present invention, the structure of the fans  130  is not complicated. Therefore, while in producing the turbine  100 , the molding process can be applied, such as the injection molding or the ejection molding. 
         [0033]    While the turbine  100  is engaged with and further driven by a motor, the turbine  100  is rotated so as to have the fans  130  to force the internal air to be guided by the curved protrusion  133  firstly, then flow in a bifurcation manner along the channels formed by the fans  130  and the auxiliary fans  131 , and finally leave the turbine  100  by a centrifugal manner via the air outlets  150  at the circumference of the turbine  100 . After the air is expelled out of the turbine  100 , the internal pressure of the turbine  100  would be dropped to be lower than the atmosphere pressure out of the air inlet  111 . Such a pressure difference would automatically draft the foreign air into the turbine  100  through the air inlet  111 , and then the air circulation pattern about the turbine  100  is then established. 
         [0034]    In the present invention, the top cover  110 , the bottom cover  120  and the fans  130  sandwiched between the top cover  110  and the bottom cover  120  are all arc-shaped. The fan  131  further includes the curved protrusion  133  disposed at a position respective to the air inlet  111  and extending in the rotational direction. Upon such an arrangement, when the foreign air is sucked into the turbine  100  through the air inlet  111 , the sucked-in air can be swiftly guided to pass the curved protrusion  133  and the channels walled by the fans  130  and the auxiliary fans  131 , and to flow out of the turbine  100  via the circumferential air outlets  150 . By compared to the conventional centrifugal fans, the turbine  100  provided by the present invention can substantially increase the air draft efficiency, and, by compared to a typical turbine, the turbine of the present invention is superior in simple structuring, easy machining and a reduced manufacturing cost. 
         [0035]    While the present invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.