Abstract:
An inflator having an enhanced cooling effect on its motor is disclosed, which includes a box composed a cover and a base, and a compressor unit installed in the box. The box is provided with airflow-guiding members cooperated with a cooling fan fitted at a rotating shaft of a motor used in the compressor unit to allow outside air to be quickly drawn into the interior of the box. Thereafter, the airflow can be guided by the airflow-guiding members to enter the interior of the motor to dissipate the heat generated by the rotor assembly in the motor and finally go out of the box. Therefore, heat is not easy to accumulate in the motor, so that maximum power output of the motor can be achieved, and the performance and service life of the motor can be increased.

Description:
(A) TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to an inflator having an enhanced cooling effect on its motor, which generally comprises a box and a compressor unit installed in the box, wherein the box is provided with air-guiding members which can guide the airflow to quickly enter the motor&#39;s housing and then go out of the housing, thus taking away the heat generated by the rotor assembly in the motor; therefore, heat is not easy to accumulate in the motor, so that the performance and service life of the motor can be increased. 
       (B) DESCRIPTION OF THE PRIOR ART 
       [0002]    Air compressors are usually employed to inflate objects such as air cushions or tires. Generally, portable air compressors are manufactured in small size, so that they can be carried easily. Furthermore, a portable air compressor can be powered by a handheld DC power supply or a cigarette lighter socket in a vehicle. Conventionally, a portable air compressor employs a box to accommodate a compressor unit therein, wherein the compressor unit employs a motor to drive a piston body to conduct reciprocating motion in a cylinder to produce compressed air, which can be transferred to an object that needs to be inflated. In operation, heat may be accumulated in the box. Since a motor includes therein a rotor assembly, which contains an armature core formed by an iron core wound with enameled wire, a commutator, and a brush unit, heat is easy to accumulate in the motor&#39;s housing. The heat accumulated in the armature core may cause the brush unit to leave more carbon deposits, thus affecting the electrical circuit of the motor. Besides, high temperature resulting from the armature core may reduce the magnetic intensity of the magnets used in the motor. Thus, the performance of the motor can be reduced. 
         [0003]    Currently, emergency repair kits, which employ a low-power motor, are used to repair punctured tires. However, in some countries, the Traffic Act stipulates that, when a vehicle has a punctured tire on a highway, the driver should repair the punctured tire within a specified period and should immediately drive away after the repair is completed to prevent rearward bump. Under these circumstances, for completing the repair as soon as possible, the motor of the compressor unit of an emergency repair kit should be operated at a higher speed. However, if heat accumulated in the motor&#39;s housing cannot be quickly taken away, the performance of the motor will decrease. Even worse, the enameled wire of the armature core will probably be damaged to cause a short circuit, and thus the motor may be burn out. 
         [0004]    In conventional inflators, a compressor unit and its motor are supported in a box through partitioning walls. However, the box is not structured to assist dissipating heat in the motor. Thus, the box is easy to accumulate the heat generated by the motor, and thus the performance of the motor can be reduced or the motor can be damaged. 
       SUMMARY OF THE INVENTION 
       [0005]    One object of the present invention is to provide an inflator, which has an enhanced cooling effect on its motor. The inflator generally comprises a box and a compressor unit, wherein the compressor unit is installed in the box composed of a cover and a base. The cover is provided with an upper airflow-guiding member. The base is provided with a lower airflow-guiding member. The upper and lower airflow-guiding members can support the motor&#39;s housing of the compressor unit. In addition, the upper and lower airflow-guiding members can guide the airflow to quickly pass through two opposite openings of the motor&#39;s housing and then go out of the motor&#39;s housing via downstream through openings defined at the rear end of the motor&#39;s housing, thus taking away the heat generated by the rotor assembly in the motor. Therefore, heat is not easy to accumulate in the motor, so that the performance and service life of the motor can be increased. 
         [0006]    Other objects, advantages, and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows an exploded view of an inflator according to one embodiment of the present invention. 
           [0008]      FIG. 2  shows a 3-dimensionally sectional view of the inflator. 
           [0009]      FIG. 3  shows a top view of the inflator. 
           [0010]      FIG. 4  shows a sectional view of the inflator. 
           [0011]      FIG. 5  shows a 3-dimensionally sectional view of the inflator, wherein the airflow induced by the cooling fan for dissipating the heat generated by the motor is demonstrated. 
           [0012]      FIG. 6  shows a schematic plan view of the inflator, which shows the relative positions of the upper airflow-guiding member, one opening of the motor&#39;s housing, the cooling fan, and the second slits. 
           [0013]      FIG. 7  shows another sectional view of the inflator. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    Referring to  FIGS. 1 and 2 , an inflator according to one embodiment of the present invention is shown, which generally comprises a box and a compressor unit. The box is composed of a cover  1  and a base  2 . The compressor unit is installed in the box. 
         [0015]    The cover  1 , which has a rectangular shape, is provided with a switch  10  for starting and stopping the compressor unit. The cover  1  has a front wall  11  and a rear wall  12 , wherein the front wall defines multiple first slits  110  to serve as an air entrance port; the rear wall  12  defines multiple second slits  120  to serve as an air exit port. Particularly, the inner surface of the cover  1  is provided with an upper airflow-guiding member  3 . The upper airflow-guiding member  3  has an upper interception wall  31 , which extends downwardly from the inner surface of the cover  1 . The upper interception wall  31  and the cover  1  are intersected at a line  30 , which has a length of (Y0) (see  FIGS. 6 and 7 ). The upper interception wall  31  can intercept the airflow in the box, as will be fully described later. Furthermore, the upper airflow-guiding member  3  has two upper air guiding plates  32 ,  33  respectively at two opposite sides of the upper interception wall  31 , extending towards the front wall  11  of the cover  1 , wherein the two upper air guiding plates  32 ,  33  may be perpendicular to the upper interception wall  31  or not. Therefore, an air guiding channel  37  is defined between the inner surface of the cover  1 , the upper interception wall  31 , and the two upper air guiding plates  32 ,  33 . If the upper air guiding plates  32 ,  33  are perpendicular to the upper interception wall  31 , the air guiding channel  37  will appear as a U-shaped channel (not shown in the drawings). If the upper air guiding plates  32 ,  33  extend outwardly from each other, towards the front wall  11  of the cover  1  (i.e. they are not perpendicular to the upper interception wall), the guiding channel  37  will appear as a V-shaped channel which can facilitate guiding the airflow in the box. Specifically, as shown in  FIGS. 6 and 7 , each of the upper air guiding plates  32 ,  33  has a first end, which is joined with one side of the upper interception wall  31 , and a second end opposite to the first end. The gap between the second ends of the two upper air guiding plates  32 ,  33  can be worked as an air entrance  34 . As shown, the distance between the first ends of the upper air guiding plates  32 ,  33  is labeled with (Y1). The distance between the second ends of the upper air guiding plates  32 ,  33  is labeled with (Y2), wherein the relationship of Y2&gt;Y1 and Y2&gt;Y0 is fulfilled. Furthermore, the cover  1  is provided with an upper wall  13  which is parallel to the front wall  11  and has a concave bottom, wherein the upper wall  13  is located behind the front wall  11 . The upper interception wall  31  of the upper airflow-guiding member  3  is formed into a curved portion  35  at its bottom to serve as a support for the motor&#39;s housing  61 . The upper interception wall  31  of the upper airflow-guiding member  3  has a slant surface  36 , which faces towards the front wall  11  to facilitate guiding the airflow in the box. 
         [0016]    The base  2  has a rectangular shape corresponding to the cover  1 . The base  2  has a front wall  21 , which can be aligned with the front wall  11  of the cover  1 , and a rear wall  22 , which can be aligned with the rear wall  12  of the cover  1 , wherein the front wall  21  defines multiple first slits  210  to serve as an air entrance port; the rear wall  22  defines multiple second slits  220  to serve as an air exit port. Particularly, the inner surface of the base  2  is provided with a lower airflow-guiding member  4 , which has the same structure as the upper airflow-guiding member  3 . The lower airflow-guiding member  4  has a lower interception wall  41 , which extends upwardly from the inner surface of the base  2 . The lower interception wall  41  and the base  2  are intersected at a line  40 , which also has a length of (Y0) (see  FIG. 7 ). The lower interception wall  41  can intercept the airflow in the box, as will be fully described later. Furthermore, the lower airflow-guiding member  4  has two lower air guiding plates  42 ,  43  respectively at two opposite sides of the lower interception wall  41 , extending towards the front wall  21  of the base  2 , wherein the two lower air guiding plates  42 ,  43  may be perpendicular to the lower interception wall  41  or not. Therefore, an air guiding channel  47  is defined between the inner surface of the base  2 , the lower interception wall  41 , and the two lower air guiding plates  42 ,  43 . If the lower air guiding plates  42 ,  43  are perpendicular to the lower interception wall  41 , the air guiding channel  47  will appear as a U-shaped channel (not shown in the drawings). If the lower air guiding plates  42 ,  43  extend outwardly from each other, towards the front wall  21  (i.e. they are not perpendicular to the lower interception wall), the guiding channel  47  will appear as a V-shaped channel which can facilitate guiding the airflow in the box. Specifically, as shown in  FIG. 7 , each of the lower air guiding plates  42 ,  43  has a first end, which is joined with one side of the lower interception wall  41 , and a second end opposite to the first end. The gap between the second ends of the two lower air guiding plates  42 ,  43  can be worked as an air entrance  44 . As shown, the distance between the first ends of the lower air guiding plates  42 ,  43  is labeled with (Y1). The distance between the second ends of the lower air guiding plates  42 ,  43  is labeled with (Y2), wherein the relationship of Y2&gt;Y1 and Y2&gt;Y0 is fulfilled. Furthermore, the base  2  is provided with a lower wall  23  which is parallel to the front wall  21  and has a concave top, wherein the lower wall  23  is located behind the front wall  21 . The lower interception wall  41  of the lower airflow-guiding member  4  is formed into a curved end portion  45  at its top to serve as a support for the motor&#39;s housing  61 . The lower interception wall  41  of the lower airflow-guiding member  4  has a slant surface  46 , which faces towards the front wall  21  to facilitate guiding the airflow in the box. 
         [0017]    Although the compressor unit is not a primary feature sought to be patented, for illustrating the technique and advantages of the present invention, the compressor unit and the motor  6  thereof will described briefly. Referring to  FIGS. 2 through 5 , the compressor unit, which can be installed between the cover  1  and the base  2 , includes a main frame  5 , a cylinder  51  joined with the main frame  5 , a motor  6  mounted at the main frame  5 , and a transmission mechanism including a pinion  81  and a gear  82 , wherein the cylinder  51  is fitted with a piston body  85 . The motor  6  is provided in its housing  61  with a rotor assembly  64 , which includes a rotating shaft  60 , an armature core having an iron core  65  wound with enameled wire  66 , a commutator  67 , an electrical terminal  68 , and a brush unit  69 . One end of the rotating shaft  60  is mounted with the pinion  81 , which is located near the front end  611  of the motor&#39;s housing  61  (see also  FIG. 6 ). The other end of the rotating shaft  60  is mounted with the cooling fan  7 , which is located near the rear end  612  of the motor&#39;s housing  61  (see also  FIG. 6 ). The housing  61  of the motor  6  defines at its circumference with two opposite openings  621 ,  622 , which respectively corresponds to the upper and lower airflow-guiding members  3 ,  4 , and defines a plurality of downstream through holes  63  at its rear end (see  FIG. 5 ). The gear  82  is attached with a counterweight  83  which is provided with a crankshaft and a crankpin  84 , wherein the crankshaft is rotatably connected to the main frame  5 , and the crankpin  84  is connected with the piston body  85 . The pinion  81  is engaged with the gear  82 . The motor  6  is installed in the box such that the curved portions  35 ,  45  of the upper and lower airflow-guiding members  3 ,  4  can firmly hold the housing  61  of the motor  6  within the box, so that the motor will not become loose, tilt or overturn. In operation, the motor  6  can drive the pinion  81  to rotate the gear  82 , which in turn can drive the piston body  85  to conduct reciprocating motion in the cylinder  51  through the crankpin  84  attached to the counterweight  83 . 
         [0018]      FIG. 6  shows the motor  6  being held between the upper and lower airflow-guiding members  3 ,  4  of the box, wherein the rear end  612  of the motor&#39;s housing  61  faces towards the first slits  110 ,  210 , and the front end  611  of the motor&#39;s housing  61  faces towards the second slits  120 ,  220 . The outer surface of the front end  611  of the motor&#39;s housing  61  is used as a vertical reference line (Y). The rotating shaft  60  of the motor  6  is used as a horizontal reference line (X). Thus, the front end  611  is at the location of X=0. As shown, the intersected lines  30 ,  40  of the upper and lower airflow-guiding members  3 ,  4  are located at a horizontal distance of (X1) from the vertical reference line (Y). The two opposite openings  621 ,  622  of the motor&#39;s housing  61  are located at a horizontal distance of (X2) from the vertical reference line (Y). The second ends of the upper and lower guiding plates  32 ,  33 ,  42 ,  43  are located at a horizontal distance of (X3) from the vertical reference line (Y). The cooling fan  7  is located at a horizontal distance of (X4) from the vertical reference line (Y). The first slits  110 ,  210  of the box are located at a horizontal distance of (X5) from the vertical reference line (Y). Among them, the relationship of X1&lt;X2&lt;X3&lt;X4&lt;X5 is fulfilled. 
         [0019]      FIGS. 3 and 5  schematically show the airflow induced by the cooling fan  7  for dissipating the heat generated by the compressor unit, wherein the curved portions  35 ,  45  of the upper and lower airflow-guiding members  3 ,  4  can contact the motor&#39;s housing  61  at a location slightly behind the two openings  621 ,  622  of the motor&#39;s housing  61 , so that the two openings  621 ,  622  are respectively located within the upper and lower air guiding channels  37 ,  47 . In operation, the cooling fan  7  can be rotated by the motor  6  to draw outside air to enter the box via the first slits  110 ,  210  and then flow through the round opening, composed of an upper part  130  and a lower part  230 , defined by the upper and lower plates  13 ,  23  for obtaining a smooth airflow, which then flows through the air entrance  34  between the two upper V-shaped air guiding plates  32 ,  33  and the air entrance  44  between the lower V-shaped air guiding plates  42 ,  43  and then is guided by the slant surfaces  36 ,  46  of the interception walls  31 ,  41  to enter the two opposite openings  621 ,  622  of the motor&#39;s housing  61 , wherein the airflow can move towards the rear end  612  of the motor&#39;s housing  61 , so that the heat generated by the commutator  67 , the brush unit  69 , and the iron core  65  with the enameled wire  66  can be dissipated effectively (see also  FIG. 4 ). 
         [0020]    As a summary, the upper and lower airflow-guiding members  3 ,  4  of the box can serve as a support for fixing the motor  6  in the box. In addition, the upper and lower airflow-guiding members  3 ,  4  of the box facilitate guiding the airflow induced by the cooling fan  7  to pass through the openings  621 ,  622  of the motor&#39;s housing  61  to take the heat generated by the rotor assembly  64  away via the downstream through openings  63  of the motor&#39;s housing  61 , so that heat is not easy to accumulate in the motor  6 , and thus maximum power output of the motor  6  can be achieved. Therefore, the performance and service life of the motor can be increased. These features render the present invention advantageous over the prior art.