Patent Document

RELATED APPLICATIONS 
     The present application claims the benefit of Japanese Application Number 2013-036028, filed Feb. 26, 2013, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a machine tool, and more particularly, to a machine tool with a cover structure adapted for the discharge of chips. 
     2. Description of the Related Art 
     In a machine tool, chips produced during machining adhere to or are deposited inside a metal plate cover that covers a machining area or on the surface of another cover component. In order to continue normal use of the machine tool, the chips must be removed. In doing this, the chips are washed away by a cutting fluid and collected in a cutting fluid supply device. 
     As described in Japanese Patent Applications Laid-Open Nos. 2007-61998 and 2006-7391, therefore, a metal plate cover that receives chips is generally shaped so that a portion thereof that contacts a casting component located in the center of a machine is formed at the lowest level and the cover is gradually elevated from the lowest portion toward its outer peripheral portion. 
     In the technique disclosed in Japanese Patent Application Laid-Open No. 2007-61998 described above, the adopted shape of the metal plate cover induces the chips and cutting fluid to collect in an area near a drive unit (not shown) of the machine. If the chips are deposited on the bottom surface of the cover, they adhere to a linear-motion guide or feed screw of a drive system, possibly causing trouble. Since the cutting fluid probably splashes, moreover, it inevitably carries away a lubricant applied to the drive system and may cause a malfunction of the machine. This problem can be partially solved by the technique described in Japanese Patent Application Laid-Open No. 2006-7391, but not fully. 
     SUMMARY OF THE INVENTION 
     Accordingly, in view of the problems of the prior art described above, the object of the present invention is to provide a machine tool with a cover structure adapted for the discharge of chips, capable of preventing such failure that the chips get into components of a drive system or a lubricant is washed away by a cutting fluid. 
     A machine tool according to the present invention comprises a table on which a workpiece is placed and a column comprising a spindle to which a tool for machining the workpiece is attached, the table and the spindle being disposed on a bed, and a cover comprising a front cover provided on the side opposite the column with the table therebetween, left and right side covers provided on the left and right sides, respectively, of the front cover, and a bottom part connected to the bed through the respective lower ends of the front cover and the side covers. At least a part of the bottom part comprises a slope that inclines outward from the side of the bed. 
     That part of the bottom part of the cover which is connected to the front cover may be configured to comprise a slope gradually inclining outward from the side connected to the bed. 
     Those parts of the bottom part of the cover which are connected individually to the left and right side covers may be configured to gradually incline rearward or forward relative to the machine tool. 
     That part of the bottom part of the cover which is connected to one of the left and right side covers may be configured to gradually incline rearward relative to the machine tool, and that part connected to the other side cover may be configured to gradually incline forward relative to the machine tool. 
     That part of the bottom part of the cover which is connected to the front cover may be configured to gradually incline from one of the left and right side covers toward the other. 
     That part of the bottom part of the cover which is connected to the front cover may be configured to comprise slopes gradually inclining from an elevated, transversely central portion thereof toward the left and right side covers. 
     Curved surfaces may be provided individually at a portion where the front cover and the left side cover intersect each other and a portion where the front cover and the right side cover intersect each other. 
     Those parts of the bottom part of the cover which are connected to the front cover and the left and right side covers may each be provided with a cutting fluid supply passage through which a cutting fluid is supplied. 
     According to the present invention, there can be provided a machine tool with a cover structure adapted for the discharge of chips, capable of preventing such failure that the chips get into components of a drive system or a lubricant is washed away by a cutting fluid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and features of the present invention will be obvious from the ensuing description of embodiments with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic top view of Embodiment 1 of a machine tool according to the present invention; 
         FIG. 2  is a schematic front view of the machine tool shown in  FIG. 1 ; 
         FIG. 3  is a schematic top view of Embodiment 2 of the machine tool according to the present invention; 
         FIG. 4  is a schematic front view of the machine tool shown in  FIG. 3 ; 
         FIG. 5  is a schematic top view of Embodiment 3 of the machine tool according to the present invention; and 
         FIG. 6  is a schematic front view of the machine tool shown in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First, Embodiment 1 of a machine tool according to the present invention will be described with reference to  FIGS. 1 and 2 . 
     A saddle  23  is supported on a bed  22  of a machine tool  40  by a saddle movement mechanism  25 , and a table  6  is supported on the saddle  23  by a table movement mechanism  24 . Further, a column  21  is set up on the bed  22 , and a spindle  3  to which a tool  4  is attached is secured to the top of the column  21 . As the spindle  3  and the table  6  are relatively moved in a machining space, the machine tool  40  machines a workpiece  5  placed on the table  6 . 
     A cover  1  isolates the saddle  23 , table  6 , column  21 , spindle  3 , and tool  4  from the outside and defines the machining space. The cover  1  comprises a front cover  30 , side covers  31  and  32 , rear cover  33 , ceiling cover (not shown), and bottom part. The front cover  30  is disposed on the side opposite to the column  21  with the table  6  therebetween. The side covers  31  and  32  are provided on the left and right sides, respectively, of the front cover  30 . The bottom part of the cover  1  comprises a cover front-bottom surface  7 , a cover left-bottom surface  9 , and a cover right-bottom surface  10 . The cover front-bottom surface  7  connects the lower end of the front cover  30  and the front end surface of the bed  22 . The cover left-bottom surface  9  connects the lower end of the left side cover  31  and the left end surface of the bed  22 . The cover right-bottom surface  10  connects the lower end of the right side cover  32  and the right end surface of the bed  22 . The cover front-bottom surface  7 , cover left-bottom surface  9 , and cover right-bottom surface  10  that constitute the bottom part may be members integral with or independent of the front cover  30 , left side cover  31 , and right side cover  32 , respectively. 
     Left and right cutting fluid supply passages  11  and  12  are disposed in the machining space to introduce a cutting fluid into the machining space that is isolated from the outside by the cover  1 . The cutting fluid is supplied from a cutting fluid supply device  2  to the left and right cutting fluid supply passages  11  and  12  through a passage (not shown). First and second cutting fluid supply nozzles  13  and  15  are provided at predetermined places of the left cutting fluid supply passage  11 , and third and fourth cutting fluid supply nozzles  14  and  16  at predetermined places of the right cutting fluid supply passage  12 . The cutting fluid is discharged in predetermined directions (see flows  27  of the cutting fluid) in the machining space from the cutting fluid supply nozzles  13  to  16 . 
     The bottom part of the cover  1  is inclined so that a portion thereof connected to the bed  22  is most elevated and that it gradually inclines from that portion toward its peripheral portion (or toward the respective lower ends of the front cover  30  and the left and right side covers  31  and  32 ). Specifically, the cover front-bottom surface  7  is a slope that gradually inclines from the side connected to the bed  22  toward the lower end of the front cover  30 . Further, the cover left-bottom surface  9  is a slope that gradually inclines from the side connected to the bed  22  toward the lower end of the left side cover  31 , while the cover right-bottom surface  10  is a slope that gradually inclines from the side connected to the bed  22  toward the lower end of the right side cover  32 . 
     Furthermore, the left and cover right-bottom surfaces  9  and  10  may be gradually inclined from the side connected to the bed  22  toward the lower ends of the left and right side covers  31  and  32 , and at the same time, gradually inclined from the front side of the cover  1  toward the rear side (or toward the rear cover  33 ). 
     Further, a corner portion where the respective lower end portions of the left side cover  31  and the front cover  30  intersect each other may be machined into a round shape with a predetermined curvature, as designated by reference numeral  17  in  FIG. 1 . Also, a corner portion where the respective lower end portions of the right side cover  32  and the front cover  30  intersect each other may be machined into a round shape with a predetermined curvature, as designated by reference numeral  18  in  FIG. 1 . In this way, the flow of chips  26  can be improved to reduce stagnation. 
     With this configuration, if the chips  26  produced by machining are deposited on the cover front-bottom surface  7  of the bottom part of the cover  1 , they are caused to flow toward the outer peripheral portion of the cover front-bottom surface  7  by the cutting fluid supplied from the second and fourth cutting fluid supply nozzles  15  and  16  and collected along the lower end of the front cover  30 . Then, the chips  26 , along with the cutting fluid, are discharged to the cover left-bottom surface  9  or the cover right-bottom surface  10 . 
     On the other hand, the chips  26  deposited on the cover left-bottom surfaces  9  and the cover right-bottom surfaces  10  of the bottom part of the cover  1 , along with the chips  26  and the cutting fluid discharged from the cover front-bottom surface  7 , are urged to flow toward and discharged into the cutting fluid supply device  2  at the back by the cutting fluid (designated by reference numeral  27  in  FIG. 1 ) supplied from the first and third cutting fluid supply nozzles  13  and  14 . 
     In the case where the chips  26  are discharged to the front surface or the left and right side surfaces of the machine tool  40 , they are discharged into the cutting fluid supply device  2  through left and right discharge passages  19  and  20  at the respective lower ends of the left and right side covers  31  and  32 , as shown in  FIG. 2 . 
     According to this embodiment, the chips  26  deposited on the bottom part of the cover  1  are urged to collect at the outer peripheral portion, the most sunken portion, of the bottom part of the cover  1  by the flows of the cutting fluid from the cutting fluid supply nozzles. Thus, the chips  26  deposited on the bottom part (comprising the cover front-bottom surface  7 , the cover left-bottom surfaces  9 , and the cover right-bottom surfaces  10 ) are discharged into the cutting fluid supply device  2  while moving along the outer peripheral portion of the cover  1 , which is located farthest from the central portion of the machining space inside the cover  1  where a drive system (comprising the saddle movement mechanism  25 , saddle  23 , table movement mechanism  24 , and table) is disposed. Consequently, it is possible to prevent failure of the machine tool that may be caused if the chips get into the components of the drive system or a lubricant is washed away by the cutting fluid. 
     Embodiment 2 of the machine tool according to the present invention will now be described with reference to  FIGS. 3 and 4 . 
     In this embodiment, the cover front-bottom surface  7  of the bottom part of the cover  1  of Embodiment 1 is divided into a cover front-left-bottom surface  7   a  and a cover front-right-bottom surface  7   b . The cover front-left-bottom surface  7   a  is gradually inclined from the side connected to a bed  22  toward the lower end of a front cover  30  and also gradually inclined toward a left side cover  31 . Further, the cover front-right-bottom surface  7   b  is gradually inclined from the side connected to the bed  22  toward the lower end of the front cover  30  and also gradually inclined toward a right side cover  32 . Thus, in this embodiment, the cover front-bottom surface  7  of the bottom part of the cover  1  is in the shape of an inverted V inclining left and right. Since other configurations are the same as those of Embodiment 1, a further description thereof is omitted. 
     In this embodiment, if chips  26  are deposited on the cover front-left-bottom surface  7   a , they are caused to flow on the cover front-left-bottom surface  7   a  by a cutting fluid supplied from a second cutting fluid supply nozzle  15  and discharged along with the cutting fluid to the cover left-bottom surface  9 . If the chips  26  are deposited on the cover front-right-bottom surface  7   b , moreover, they are caused to flow on the cover front-right-bottom surface  7   b  by the cutting fluid supplied from a fourth cutting fluid supply nozzle  16  and discharged along with the cutting fluid to the cover right-bottom surface  10 . On the other hand, the chips  26  deposited on the cover left-bottom surface  9  and the cover right-bottom surface  10 , along with the chips  26  and the cutting fluid discharged from the cover front-left-bottom surface  7   a  and the cover front-right-bottom surface  7   b , are urged to flow toward and discharged into a cutting fluid supply device  2  at the back by the cutting fluid (designated by reference numeral  27  in  FIG. 1 ) supplied from first and third cutting fluid supply nozzles  13  and  14 . 
     Embodiment 3 of the machine tool according to the present invention will now be described with reference to  FIGS. 5 and 6 . 
     This embodiment resembles Embodiment 2 described above in that a cover front-bottom surface  7  of a bottom part of a cover  1  is divided into the cover front-left-bottom surface  7   a  and the cover front-right-bottom surface  7   b  so that it is in the shape of an inverted V inclining left and right. However, this embodiment differs from Embodiment 2 in that the cover front-left-bottom surface  7   a  and the cover front-right-bottom surface  7   b  are not inclined from the side connected to a bed  22  toward the lower end of a front cover  30 . Since other configurations are the same as those of Embodiment 1, a further description thereof is omitted. 
     In the machine tool according to the present invention, as described above, the cover comprises the front cover, left and right side covers, and bottom part, and the bottom part is connected to the bed of the machine tool through the respective lower ends of the front and side covers. According to the present invention, moreover, the bottom part of the cover comprises slopes that at least partially inclines from the side connected to the bed toward the outer periphery. The following is a description of some examples of the form of the bottom part of the cover  1  that characterizes the invention. 
     EXAMPLE 1 
     Of the bottom part of the cover  1 , the cover left-bottom surfaces  9  connected to the left side cover  31  and the cover right-bottom surfaces  10  connected to the right side cover  32  are slopes that incline outward (or toward the left and right side covers  31  and  32 ) from the side connected to the bed  22 . 
     EXAMPLE 2 
     Of the bottom part of the cover  1 , the cover front-bottom surface  7  connected to the front cover  30  is a slope that inclines outward (or toward the front cover  30 ) from the side connected to the bed  22 . 
     EXAMPLE 3 
     Of the bottom part of the cover  1 , the cover left-bottom surfaces  9  connected to the left side cover  31  and the cover right-bottom surfaces  10  connected to the right side cover  32  are slopes that individually incline rearward or forward relative to the machine tool  40 , in addition to Example 1 or 2. 
     EXAMPLE 4 
     Of the bottom part of the cover  1 , the cover left-bottom surface  9  connected to the left side cover  31  is a slope that inclines rearward relative to the machine tool  40 , and the cover right-bottom surface  10  connected to the right side cover  32  is a slope that inclines forward relative to the machine tool  40 , in addition to Example 1 or 2. Alternatively, the cover left-bottom surface  9  connected to the left side cover  31  is a slope that inclines forward relative to the machine tool  40 , and the cover right-bottom surface  10  connected to the right side cover  32  is a slope that inclines rearward relative to the machine tool  40 , in addition to Example 1 or 2. 
     EXAMPLE 5 
     Of the bottom part of the cover  1 , the cover front-bottom surface  7  connected to the front cover  30  is a slope that inclines from the side of the left side cover  31  toward the right side cover  32 , or vice versa, in addition to Example 2 or 4. 
     EXAMPLE 6 
     Of the bottom part of the cover  1 , the cover front-bottom surface  7  connected to the front cover  30  comprises slopes that incline from its central portion to the left and right (or toward the left and right side covers  31  and  32 ), in addition to any one of Examples 1 to 3. 
     EXAMPLE 7 
     A portion (or junction) where the front cover  30  and the left side cover  31  intersect each other and a portion (or junction) where the front cover  30  and the right side cover  32  intersect each other are curved surfaces with a predetermined curvature, in addition to any one of Examples 1 to 6. 
     EXAMPLE 8 
     The bottom part of each of the front cover  30  and the left and right side covers  31  and  32  is provided with left and right cutting fluid supply passages  11  and  12 , in addition to any one of Examples 1 to 6.

Technology Category: 7