Abstract:
A barrel polishing device for polishing a workpiece having a relatively complicated shape such as a vehicle wheel. The barrel polishing device comprises a polishing medium storage tank for storing polishing media, a base, a workpiece supporting shaft mounted on the base, and a workpiece detachably mounted on a tip part of the workpiece supporting shaft, the polishing media stored in the polishing medium storage tank being flowed by an appropriate means, and the workpiece supporting shaft being disposed so that a front side of the workpiece opposes the flow of the polishing media, the workpiece supporting shaft being rotated about an axis thereof, and a baffle member being placed in the vicinity of a back side of the workpiece.

Description:
TECHNICAL FIELD 
   This invention relates to a barrel polishing device which is used for barrel polishing, for example, a vehicle wheel. 
   BACKGROUND ART 
   Conventionally, when a vehicle wheel is to be barrel polished, it was an ordinary practice that the front side of the vehicle wheel is arranged in such a manner as to oppose to the flow of polishing media in the state slanted forward, and the side of the vehicle wheel is polished by flowing the polishing media along the front side of the vehicle wheel while rotating the vehicle wheel (about the axis). 
   The polishing media, which have polished the front side, are turned from the perimeter of the vehicle wheel and stored in the back. 
   In this conventional barrel polishing method, however, the back of the vehicle wheel is difficult to polish because the polishing media stored in the back side of the vehicle wheel are flown away backward while turning by the turning force of the vehicle wheel. 
   It is, therefore, an object of the present invention to overcome the above-mentioned inconvenience. 
   SUMMARY OF THE INVENTION 
   In order to overcome the above-mentioned inconvenience, the inventor of the present invention made extensive research and development and accomplished this invention. 
   According to the present invention, there is provided a barrel polishing device comprising a polishing medium storage tank for storing polishing media, a base, a workpiece supporting shaft mounted on the base, and a workpiece detachably mounted on a tip part of the workpiece supporting shaft, the polishing media stored in the polishing medium storage tank being flowed by an appropriate means, and the workpiece supporting shaft being disposed so that a front side of the workpiece opposes the flow of the polishing media, the workpiece supporting shaft being rotated about an axis thereof, and a baffle member being placed in the vicinity of a back side of the workpiece. Accordingly, the flow of the polishing media stored in the back side of the workpiece is interfered with the baffle. Consequently, the surface pressure of the polishing media with respect to the back side of the workpiece can be increased. 
   Thus, in this barrel polishing device, since both the front and back sides of the workpiece can be polished simultaneously, the polishing efficiency of the barrel polishing for the workpiece can easily be enhanced. 
   Moreover, since the entire workpiece is simultaneously polished, the surface of the workpiece is activated. As a result, the coating adhesion, which is to be taken place in the succeeding process, is enhanced. In addition, since the surface hardening of the workpiece is caused by the polishing media, the workpiece is enhanced in strength. 
   If the workpiece is provided with a window, the corner parts of the back side of this window can be simultaneously polished in the shape of an R, the coating thickness in the succeeding process can be uniformed. As a result, generation of rust can be prevented and strength can be enhanced by preventing concentration of stress. 
   If the baffle member is capable of advancing and retracting with respect to the back side of the workpiece, the spacing between the back side of the workpiece and the baffle member is adjustable and therefore, the surface pressure of the polishing media with respect to the back side of the workpiece can be adjusted. Thus, the application range can be expanded. 
   If the baffle member is formed of an elastic material, since the baffle member is swung, the endurance of the baffle member can be maintained even if the flow pressure of the baffle member (at the back side of the workpiece), which is turned and flowed together with the workpiece, is changed. 
   If the baffle member is formed in the shape of a tongue, since the swinging can be made more easily, the endurance of the baffle member can be maintained over a longer period of time. 
   If an outer configuration of the baffle member is generally coincident with a configuration of the back side of the workpiece, since the surface pressure of the polishing media with respect to the back side of the workpiece can be maintained generally at a constant level, uniformed polishing can be carried out. 
   If the baffle member is placed in the vicinity of a lower part of the back side of the workpiece, the flow of the polishing media stored in a lower side of the back side of the workpiece is interfered with the baffle. As a result, the surface pressure of the polishing media with respect to the back side at the lower part of the workpiece can be increased. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a sectional view of a barrel polishing device according to one embodiment of the present invention. 
       FIG. 2  is a view when viewed in a direction as indicated by an arrow II of  FIG. 1 . 
       FIG. 3  is a view when viewed in a direction as indicated by an arrow III of  FIG. 1 . 
       FIG. 4  is a sectional view taken on line IV—IV of  FIG. 3 . 
       FIG. 5  is a view like  FIG. 1  but showing another embodiment of the present invention. 
       FIG. 6  is a view like  FIG. 1  but showing a further embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the embodiments to be described hereinafter, a “vehicle wheel” will be employed as one example of a workpiece. 
     FIG. 1  is a sectional view of a barrel polishing device according to one embodiment of the present invention,  FIG. 2  is a view when viewed in a direction as indicated by an arrow II of  FIG. 1 ,  FIG. 3  is a view when viewed in a direction as indicated by an arrow III of  FIG. 1 ,  FIG. 4  is a sectional view taken on line IV—IV of  FIG. 3 , and  FIG. 5  is a view like  FIG. 1  but showing another embodiment of the present invention. 
   In  FIGS. 1 and 2 , reference symbol B denotes a barrel polishing device and  10  denotes its base. Reference numeral  20  denotes a polishing media storage tank which is mounted on the base  10 . This polishing media storage tank  20  is in the shape of a circular cylinder. The polishing media storage tank  20  is turnable in a peripheral direction about an axis O by an appropriate turning means (see an arrow of  FIG. 1 , indicating the turning direction about the axis O). Reference numeral  21 ,  21 , . . . denote polishing media which are stored in this polishing media storage tank  20 . In accordance with the turn of the polishing media storage tank  20  in the peripheral direction, the polishing media  21 ,  21 , . . . are flown in the same direction. As the polishing media  21 ,  21 , . . . , those normally used, such as ceramics, may be used. The polishing method may be either wet or dry type polishing. 
   Reference numeral  22  denotes an upper end opening of the polishing media storage tank  20 . Through this upper end opening  22 , an aluminum-made vehicle wheel (corresponding to the “workpiece” of the present invention) W as later described is dipped into the polishing media  21 ,  21 , . . . . 
   Reference numeral  11  denotes a supporting frame which is raised from the base  10 . This supporting frame  11  extends generally to the upper end of the polishing media storage tank  20 . 
   Reference numeral  30  denotes a reversible plate which is mounted on the supporting frame  11  through a rotation shaft  31 . This reversible plate  30  is reciprocally reversible in the range of approximately 180 degrees in accordance with the rotation of the rotation shaft  31 . The rotation shaft  31  is driven for rotation by an appropriate rotation driving means such as a motor. 
   Reference numeral  41  denotes a supporting plate which is installed at the end edge part of the reversible plate  30 . This supporting plate  41  extends upward. Reference numeral  40  denotes a supporting bed which is fixed to a forward end part of the supporting plate  41 . This supporting bed  40  is arranged in its perpendicular posture. 
   Reference numeral  51  denotes a first driving motor which is mounted on the supporting bed  40 . The turning force of this first driving motor  51  is transmitted through a driving sprocket  52 . Reference numeral  60  denotes a workpiece supporting shaft which is turnably mounted on the supporting bed  40  through bearings  61 ,  61 . This workpiece supporting shaft  60  projects in a direction of the polishing media storage tank  20  (see  FIG. 1 ). Reference numeral  62  denotes a driven sprocket which is mounted on a rear end part of the workpiece supporting shaft  60 . A chain  53  is wound around this driven sprocket  62  and the driving sprocket (of the first driving motor  51 )  52 , so that the turning force of the first driving motor  51  is transmitted thereto at a reduced speed. 
   The aluminum-made vehicle wheel W is removably attached to the forward end of this workpiece supporting shaft  60  through an actuator (not shown) and dipped in the polishing media  21 ,  21 , . . . of the polishing media storage tank  20 . Thus, in accordance with the revolution of the first driving motor  51 , the workpiece supporting shaft  60  is turnable about its axis. 
   At that time, the aluminum-made vehicle wheel W is held in the state in which its front part is slanted toward the flow of the polishing media  21 ,  21 , . . . (see the state of  FIG. 1 ). The workpiece supporting shaft  60  can intermittently turn normally and reversely. 
   The vehicle wheel W is of the type in which a rim part  72  is integrally formed around a disc part  71 . Windows  73 ,  73 , are formed at this disc part  72 . 
   Reference numeral  80  denotes an advance and retreat rod which is advanceably and retreatably (along the axis) mounted on the supporting bed  40  through bearings  81 ,  81 . This advance and retreat rod  80  is arranged at a lower part of the workpiece supporting shaft  60  in a generally parallel relation. Reference numeral  82  is a basal part. In the advance and retreat rod  80 , the basal part  82  is fixed between the bearings  81 ,  81 . Nut members  83 ,  83  are fixed to this basal part  82 . 
   On the other hand, reference numeral  84  denotes a second driving motor which is mounted on the supporting bed  40 . This second driving motor  84  is provided with a reduction mechanism. Reference numeral  85  denotes a bolt pin which is turnably installed on the supporting bed  40  through bearings  86 ,  86 . This bolt pin  85  is turned about the axis by the second driving motor  84 . The bolt pin  85  is threadingly engaged with the nut members  83 ,  83 . Owing to this arrangement, when the bolt pin  85  is turned, the nut members  83 ,  83 , and thus the advance and retreat rod  80 , are advanced and retracted. 
   Reference numeral  90  denotes a baffle member which is removably mounted on the forward end of the advance and retreat rod  80 . This baffle member  90  is placed in the vicinity of a lower part on the back side of the vehicle wheel W. The baffle member  90  is formed in the shape of a tongue from elastic material such as synthetic resin. Owing to this feature, since the baffle member  90  can easily swing, the endurance of the baffle member  90  can be maintained even if the flow pressure of the polishing media  21 ,  21 , . . . is changed. Moreover, if the baffle member  90  is formed in the shape of a tongue, it can more easily swing and therefore, the endurance of the baffle member  90  can be maintained over a longer period of time. Moreover, since the outer configuration of the peripheral edge of the baffle member  90  is made generally coincident with the configuration of the back side of the vehicle wheel W (see  FIG. 1 ), the surface pressures of the polishing media  21 ,  21 , . . . can be maintained at a generally constant level and therefore, uniformed polishing can be achieved. 
   Operation of the barrel polishing device B will now be described briefly. 
   In this barrel polishing device B, the aluminum-made vehicle wheel W is fixed to the forward end of the workpiece supporting shaft  60  and while rotating the same, the vehicle wheel W is sunk in the polishing media  21 ,  21 , . . . of the polishing media storage tank  20 . Then, the polishing media  21 ,  21 , . . . , which have passed through the windows  73 ,  73  of the vehicle wheel W, are mostly stored on the back side of the vehicle wheel W. Then, while rotating and flowing (see the direction as indicated by an arrow of  FIG. 4 ) in accordance with the rotation of the vehicle wheel W, the polishing media  21 ,  21 , . . . flow backward. In this situation, as shown in  FIGS. 3 and 4 , when the advance and retreat rod  80  is brought to the vicinity of the back side of the disc part  71 , the flow of the polishing media  21 ,  21 , . . . is urged against the disc part  71  by the peripheral edge of the baffle member  90  so that this part is polished. Especially, since the corner parts at the back side of a spoke part constituting the window  73  can be simultaneously polished in the shape of R, the coating thickness in the succeeding process can be uniformed. As a result, generation of rust can be prevented and strength can be enhanced by preventing concentration of stress. Moreover, since the baffle member  90  is made advanceable and retractable with respect to the back side of the vehicle wheel W, the surface pressure of the polishing media  21 ,  21 , . . . with respect to the back side of the vehicle wheel W is adjustable. 
   As the polishing media in this polishing device B, a granular body, a lump or the like of a soft material such as, for example, sponge, rubber, soft plastics and the like can be used. By using selected one of those materials, the finish polishing can be conducted in an efficient manner. It is also accepted that a soft material is coated on the surface of a hard grain, a hard lump or the like, so as to be used as the polishing media. 
   After the barrel polishing is carried out, a surface treatment such as coating, plating and anodizing is conducted. Those surface treatments include all of the normally available treatments. 
   Although a vehicle wheel is employed as a workpiece in this embodiment, the present invention is not limited to it. Needless to say, all objects to be polished can be included therein. 
     FIG. 5  shows another embodiment of the present invention. In this embodiment, the workpiece supporting shaft  60  is arranged perpendicular to the flowing direction of the polishing media  21 . In this embodiment, the polishing media  21  flow along the front and back surfaces of the vehicle wheel W. The polishing media  21  flowing along the back surface of the vehicle wheel W are urged against the disc part  71  by the peripheral edge of the baffle member  90 , so as to polish this part. 
   When the vehicle wheel W enters the polishing media downward, the polishing media  21  flow from the front surface to the back surface and therefore, the same effect as in the above-mentioned embodiment can be obtained. 
     FIG. 6  shows a further embodiment of the present invention. In this embodiment, the workpiece supporting shaft  60  is arranged horizontal to the flowing direction of the polishing media  21 . The polishing media  21  are collided with the front surface of the vehicle wheel W and mostly stored on the back side of the vehicle wheel W after passing through the windows  73 ,  73 , . . . . At this time, as shown in  FIG. 6 , when the advance and retreat rod  80  is brought to the vicinity of the back side of the disc part  71 , the flow of the polishing media  21 ,  21 , . . . is urged against the disc part  71  by the peripheral edge of the baffle member  90 , so as to polish this part. As a means for turning the workpiece supporting shaft  60 , the conventionally available drive transmitting means (rotation transmitting means in the perpendicular direction) such as a bevel gear is used. Similarly, as a means for advancing and retreating the advance and retreat rod  80 , a conventionally available drive transmitting means (means for converting a rotating motion into an advancing and retreating motion) such as a rack and a pinion is used. 
   As mentioned above, since a barrel polishing device according to the present invention is effectively used for a member which needs a polishing effect on the back side such as a vehicle wheel because it is excellent in polishing effect at the back side of a rotating workpiece.