Abstract:
A work-machine splash guard for enclosing a space for machining a workpiece, and preventing the spraying of chips and machining fluid, is equipped with: a front-surface door for opening and closing in the horizontal direction via an arc-shaped movement, and positioned on the front-surface side of the work machine; a side-surface door for opening and closing by performing an arc-shaped movement that is concentric with the front-surface door, and overlapping with the front-surface door; and door-locking switches for selectively allowing the opening/closing of the front-surface door and the side-surface door according to an opening/closing pattern.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Phase patent application of PCT/JP2012/066185, filed on Jun. 25, 2012, which is hereby incorporated by reference in the present disclosure in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a machine tool, in particular a machine tool provided with a splashguard for preventing chips and machining liquid from scattering during machining of a workpiece under NC (numerical control). 
       BACKGROUND OF THE INVENTION 
       [0003]    Conventionally, splashguards, enclosing machine tools, have been used in order to prevent chips and machining liquid from scattering during machining in machine tools. Splashguards generally are provided with a door provided in a front panel or a side panel in order to access a tool attached to the end of a spindle or a workpiece which is machined by the tool. For example, Patent Document 1 discloses a machine tool cover provided with a plurality of arcuate doors. 
         [0000]    Patent Document 1: Japanese Unexamined Patent Publication No. H11-114767 
       SUMMARY OF THE INVENTION 
       [0004]    According to the cover for a machine tool of Patent Document 1, the plurality of arcuate doors are opened and closed through arcuate motions. However front side door cannot be singly opened and close. Therefore, it encounters a problem that all of the doors must be opened in order to access the front part of a machining region, and accordingly any design of interlock must deactivate completely the machining process by deactivating the rotation of spindle and the supply of machining liquid. 
         [0005]    The invention is directed to solve the problem of the prior art, and the objective of the present invention is to provide a machine tool with a splashguard provided with a plurality of linear or arcuate doors configured so that a door (front door) adjacent a preparation chamber can be singly opened and closed or a door (lateral side door) adjacent a machining chamber can be singly opened and closed. 
         [0006]    Further, the objective of the present invention is to provide a machine tool with a compact and convenient splashguard improved to ensure the safety and the efficiency of manual tool change and a preparation during machining with a double-sided workpiece mount. 
         [0007]    According to the present invention, there is provided a splashguard for enclosing a space for machining a workpiece and preventing chips and machining liquid from scattering, characterized in that the splashguard comprises: 
         [0008]    a preparation chamber side door provided at the preparation chamber side of the machine tool so as to horizontally open and close; 
         [0009]    a machining chamber side door disposed adjacent the preparation chamber side door so as to open and close in the same direction; 
         [0010]    a door locking switch for allowing selectively the preparation chamber side door and machining chamber side door to be opened and closed depending on opening and closing patterns. 
         [0011]    According to the present invention, the preparation chamber side door (front door) and the machining chamber side door (lateral side door) can be separately opened and closed in the same direction, and therefore selectively opened and closed as needed. The provision of a door locking switch which allows selectively the opening and closing of the preparation chamber side door (front door) and the machining chamber side door (lateral side door) depending on opening and closing patterns provides convenient door opening and closing patterns, for example, allowing the doors to be opened only when the spindle of a machine tool and supply of the machining liquid are deactivated whereby the effect of the production and the safety are ensured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a side view schematically showing the configuration of a machine tool according to an embodiment of the invention. 
           [0013]      FIG. 2  is a rear view of the machine tool in the direction of arrows  2 - 2  in  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view of the exterior of the machine tool with a splashguard enclosing the machine tool. 
           [0015]      FIG. 4  is a partial sectional view of the splashguard of  FIG. 3  showing sliding doors according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    With reference to the drawings, an embodiment of the invention will be described below.  FIG. 1  is a side view schematically showing the structure of a machine tool according to an embodiment of the invention.  FIG. 2  is a rear view of the machine tool viewing in the direction of arrows  2 - 2  in  FIG. 1 .  FIG. 3  is a perspective view schematically showing the exterior of the machine tool with a splashguard.  FIG. 4  is a partial sectional view of the splashguard of  FIG. 3  showing sliding doors according to an embodiment of the invention. In this specification, a front side of the machine tool is defined by the direction of the tip of a tool attached to the end of a spindle as described below. 
         [0017]    In this embodiment, as an example, a machine tool  10  may be a four-axis horizontal machining center having liner feed axes extending in three orthogonal X-, Y- and Z-axes directions and a B-axis providing a rotary feed axis. The left-right direction (perpendicular to the plane of  FIG. 1 ) of the machine tool  10  is defined as the X-axis, the vertical direction is defined as the Y-axis, and the front-rear direction (the left-right direction in  FIG. 1 ) is defined as the Z-axis. The B-axis is a rotary feed axis about a vertical axis parallel to the Y-axis. The machine tool  10  may be, instead of a four-axis horizontal type, for example, a five-axis machine, a vertical machining center, a milling machine, an electric discharge machine, etc. 
         [0018]    The machine tool  10  comprises a bed  12  providing a base supported on a floor of a factory. The bed  12  comprises a bed body  13  in the form of a hollow substantially rectangular column and a pair of side walls  14  rearwardly extending in Z-axis direction from a rear face of the bed body  13 . The bed  12  is supported by a plurality of, in this embodiment three height-adjustable leveling blocks as supporting members. In particular, the bed  12  is supported by a front leveling block  11   a , disposed at the front side center of the bed body  13 , and rear leveling blocks  11   b  disposed at the respective rear ends of the pair of side walls  14 . 
         [0019]    On the top surface of the bed body  13 , a table  15  is arranged. The table  15  is driven by a B-axis servomotor  15   a , incorporated in the bed body  13  to rotate about a rotational axis, i.e., B-rotary feed axis, parallel to the Y-axis. On the table  15 , a double-faced workpiece mount  16  is fastened. The double-faced workpiece mount  16  includes oppositely defined mounting faces  16   a  and  16  for mounting workpiece W. 
         [0020]    The machine tool  10  comprises a vertically moving body  21  disposed for linear reciprocal movement in the vertical direction along the Y-axis at the back of the bed body  13 . At the top of the vertically moving body  21 , a left-right moving body  23  is mounted for liner reciprocal movement in the left-right direction along the X-axis. A front-rear moving body  24  is mounted to the left-right moving body  23  for liner reciprocal movement in the front-rear direction along the Z-axis. Mounted to the front-rear moving body  24  is a spindle head  25  for supporting a spindle  26  for rotation about a rotational axis O parallel to the Z-axis. A tool  27  is detachably attached to the end of the spindle  26  so as to face the workpiece W mounted to one of the double-faced workpiece mount  16 . 
         [0021]    Mounted to the rear side of the bed body  13  are Y-axis guide rails  28 , providing a pair of left-right guides extending in the Y-axis direction (vertical direction), and Y-axis ball screws  35 , providing a pair of vertical feed screws, disposed outside the Y-axis guide rails  28  so as to extend in the Y-axis direction. Further, brackets  31  are disposed in the rear side of the bed body  13 . In this embodiment, the brackets  31  are integrally formed with the side walls  14  so as to extend from the inner side surfaces of the side walls  14 . Y-axis servomotors  30 , as vertically feed motors, are mounted to and the Y-axis ball screws  35  are rotationally supported by the brackets  31 . Brackets  31  define through holes  32  extending in the Y-axis direction from the top surface to the bottom surface, wherein the Y-axis servomotors  30  are mounted to the bottom surfaces of the brackets  31  so that their output shafts  30   a  extends upwardly through the respective through holes  32 . The output shafts  30   a  are connected to the lower ends of the Y-axis ball screws  35  by couplings  34 . Y-axis ball screws  35  are disposed as possible as near the rear leveling blocks  11   b.    
         [0022]    The vertically moving body  21  comprises a pair of left-right legs  22  which are apart from each other or formed into a bifurcated fork downwardly extending in the Y-axis direction. Y-axis guide blocks  29  are mounted to the vertically moving body  21 . The vertically moving body  21  is supported on the Y-axis guide rails  28  through the Y-axis guide blocks  29  for sliding along the Y-axis guide rails  28 . As shown in  FIG. 2 , the Y-axis guide blocks  29  are position so that the Y-axis guide rails  28  are overlapped by the pair of legs  22  when the vertically moving body  21  is mounted to the rear side of the bed body  13 . In particular, the vertically moving body  21  is provided with a pair of top and bottom Y-axis guide blocks  29  for each of the pair of Y-axis guide rails  28  whereby at least one of the Y-axis guide blocks  29  of each of the pairs is always disposed on each of the pair of legs  22 . 
         [0023]    Further, mounted to the vertically moving body  21  are nuts  36  for engaging the Y-axis screws  36 . When the Y-axis servomotors  30  are rotated, the vertically moving body  21  is vertically driven in accordance with the direction and the amount of the rotation of the Y-axis servomotors  30 . In this connection, the Y-axis servomotors  30  and the Y-axis ball screws  35  provide vertically moving means of the invention. Provision of at least one of the Y-axis ball screws  35  may be sufficient. The left-right size of the vertically moving body  21  may be a minimum length allowing the vertically moving body to accommodate the guide blocks  29  whereby the vertically moving body may have laterally extending portions for mounting the nuts  36  to reduce its weight. 
         [0024]    Mounted to the top of the vertically moving body  21  are X-axis guide rails  37 , providing a pair of left-right guides extending in the X-axis direction, and an X-axis ball screw  41 , providing a left-right feed screw disposed between the pair of the X-axis guide rails  37  so as to extend in the X-axis direction. X-axis guide blocks  38  are mounted to the left-right moving body  23 . The left-right moving body  23  is supported on the X-axis guide rails  37  through the X-axis guide blocks  38  for sliding along the X-axis guide rails  37  in the left-right direction. An X-axis servomotor  39  is mounted to the vertically moving body  21  as a left-right feed motor. Output shaft (not shown) of the X-axis servomotor  39  is connected to the X-axis ball screw  41  by a coupling (not shown). A nut  42 , engaging the X-axis ball screws  41 , is mounted to the left-right moving body  23  whereby when the X-axis servomotor  39  is rotated, the left-right moving body  23  is driven in the left-right direction in accordance with the direction and the amount of the rotation of the X-axis servomotor  39 . The X-axis servomotor  39  and the X-axis ball screw  41  provide left-right driving means of the invention. 
         [0025]    Mounted to the top of the left-right moving body  23  are Z-axis guide rails  43 , providing a pair of front-rear guides extending in the Z-axis direction, and a Z-axis ball screw  46 , providing a front-rear feed screw disposed between the pair of the Z-axis guide rails  43  so as to extend in the Z-axis direction. Z-axis guide blocks  44  are mounted to the front-rear moving body  24 . The front-rear moving body  24  is supported on the Z-axis guide rails  43  through the Z-axis guide blocks  44  for sliding along the Z-axis guide rails  43  in the front-rear direction. A Z-axis servomotor  45  is mounted to the left-right moving body  23  as a front-rear feed motor. An output shaft (not shown) of the Z-axis servomotor  45  is connected to the Z-axis ball screw  46  by a coupling (not shown). Nut  42 , engaging the Z-axis ball screw  46 , is mounted to the front-rear moving body  24  whereby when the Z-axis servomotor  45  is rotated, the front-rear moving body  24  is driven in the front-rear direction in accordance with the direction and the amount of the rotation of the Z-axis servomotor  45 . The Z-axis servomotor  45  and the Z-axis ball screw  46  provide front-rear driving means of the invention. 
         [0026]    A built-in type spindle motor (not shown) is incorporated in the spindle head  25 . The spindle  26  and tool  27  are rotationally driven by the spindle motor about the rotational axis O. The tool  27  is moved relative to the workpiece W by the linear motion of the left-right moving body  21  and the front-rear moving body  24  in the X-, Y- and Z-axes directions. The relative movement is controlled by an NC device (not shown) incorporated in the machine tool  10 . The rotating tool  27  contact the workpiece W at a machining point when the tool  27  and the workpiece W move relative to each other. Accordingly, the workpiece is machined into a desired shape. 
         [0027]    As shown in  FIG. 1 , the bed body  13  defines an upwardly opening cavity  51 . A chute  52  is defined in the inner wall of the cavity  51  under the table  15 . The rear side of the bed body  13  defines an opening  13   a  as an outlet for chips. The chute  52  is defined by a slope lowering from the front side of the bed body  13  rearwardly toward the opening  13   a  and downwardly inclined surfaces defined by the left and right inner walls. The chips generated during the machining of the workpiece W and the machining liquid injected to machining areas in the workpiece W will fall from around the table  15  into the cavity  51 , then move toward the opening  13   a  along the chute  52 . 
         [0028]    A chip removing duct  53 , for removing the chips and the machining liquid outside the machine tool, i.e., outside the cavity  51  of the bed body  13 , is mounted to the rear side of the bed body  13 . The chip removing duct  53  extends rearwardly from the rear side of the bed body  13  to pass between the legs  22  of the vertically moving body  21 . The chip removing duct  53  is mounted at one end thereof to the rear side of the bed body  13  by for example screws bolts so as to enclose the opening  13   a . The other end  53   b  of the duct  53  is configured to be connected to a chip receptacle  56 . The chip receptacle  56  is a member in the form of an upwardly opening shallow tray having a meshed bottom wall (now shown). A machining liquid reservoir  54  is placed under the chip receptacle  56 . The chip removing duct  53  is downwardly inclined, i.e., closing the floor, from the chute  52  toward the machining liquid reservoir  54 . Thus, the chips and the machining liquid, discharged outside the machine tool through the opening  13   a , are directed to the chip receptacle  56  by the chip removing duct  53 . In the chip receptacle  56 , the machining liquid will fall into the machining liquid reservoir  54  after it is filtered by the meshed bottom wall of the chip receptacle  56  whereby only the chips are deposited on the bottom wall of the chip receptacle  56 . The chips remaining in the chip receptacle  56  will be periodically collected by an operator. 
         [0029]    The machining liquid reservoir  54  contains the machining liquid from the chute  52  through chip removing duct  53 . A pump  55  is mounted to the machining liquid reservoir  54 . The pump  55  directs the machining liquid, contained in the machining reservoir  54 , to the machining areas in the workpiece W. A filter (not shown) may be provided in the machining liquid reservoir  54  in order to further remove fine chips before the supply to the machining areas. Thus, the machining liquid is reused. 
         [0030]    The machine tool  10  is provided with a splashguard  61  in the form of for example a box containing all of the above-described components. The splashguard  61  a front panel  62 , left and right side panels  63   a  and  63   b  and a top panel  64 , respectively covering a front lower part, the sides and the top and rear side of the machine tool  10 . A front upper part of the machine tool  10 , in particular the space where the double-faced workpiece mount  16  is disposed, is covered by slid doors  65  and  66 . The slide doors  65  and  66  include rectangular monitoring windows  65   a  and  66   a . Transparent glass plates are fitted in the monitoring windows. 
         [0031]    A control panel  68  is incorporated in the right side panel  63   b . The control panel  68  is connected to the above-described NC device. In the control panel  68 , a display panel, displaying the operation states of the above-described components, and a various input buttons are disposed. An operator of the machine tool  10  can input a machining program and a various machining parameters to the NC device. A machining program may be input through a communication network, such as a LAN in a factory. 
         [0032]    With reference to  FIG. 4 , the space above the bed  12  where the double-faced workpiece mount  16  is disposed is a machining region enclosed by a fixed arcuate wall  74 , first and second movable sliding doors  65  and  66  and a sliding plate  71 . The first sliding door  65 , providing a preparation chamber door (a front door), is disposed at the front side of the machine tool  10  for arcuate motion about the center O′ in the horizontal direction so as to open and close. The second sliding door  66 , providing a machining chamber door (a side door) moves arcuately about the center O′ the same as the first sliding door  65  so as to overlap with the first sliding door  65  for opening and closing. In this embodiment, the center O′ for the arcuate motions of the first and second sliding doors  65  and  66  is aligned with the rotational axis O of the spindle  27  when the spindle head  25  is positioned at the center of the X-axis stroke. Further, handles  65   b  and  66   b  are attached to the first and second sliding doors  65  and  66  respectively for opening and closing. 
         [0033]    In the machining region, a partition wall  70  extends, in a plane including the rotational axis, B-axis, of the table  15 , perpendicularly to the rotational axis O of the spindle  26 . When the table  15  is rotated about B-axis so that the double-faced workpiece mount  16  is substantially perpendicular to the axis O of the spindle  26 , as shown in  FIG. 4 , the machining region is divided into a preparation chamber  72 , defined by the near side or front side first sliding door  65 , the partition wall  70  and the double-faced workpiece mount  16 , and a machining chamber  73 , defined by the far side or arcuate wall  74 , the partition wall  70 , the double-faced workpiece mount  16 , the sliding plate  71  and the flank second sliding door  66 . The sliding plate  71  follows the movement of the spindle head  25  so as to always close the rear side of the machining chamber  73 . The first and second sliding doors  65  and  66  can be independently slid whereby an operator can access the preparation chamber  72  by sliding to open the first sliding door  65  in direction of arrow A, and also can access the machining chamber  73  by sliding to open the second sliding door  66  in the direction of the arrow A. 
         [0034]    The machine tool  10  is further provided with an interlock for preventing the opening of the first and second sliding doors  65  and  66  in connection with the operating status of the machine tool  10 . With reference to  FIG. 4 , the first sliding door  65  is provided with a first door locking switch  75 , and the second sliding door  66  is provided with a second door locking switch  76 . It should be noted that the door locking switch  75  is placed in a position so as to not interrupt the opening and closing motion of the second sliding door  66 . The first and second door locking switches  75  and  76  include a contact (not shown), which allows electric current to flow to an interlock circuit (not shown) across the door locking switches when the first and second sliding doors  65  and  66  are closed, and a locking mechanism (not shown), which blocks, when the interlocking circuit inhibits the opening of the sliding doors, the opening of the first and second sliding doors  65  and  66  according to the interlock inhibition. A programmable controller using a limit switch or solenoid may be used as the interlock circuit. 
         [0035]    The first and second sliding doors  65  and  66  are not limited to the arcuate doors which arcuately move to open and close. For example, in  FIG. 4 , a splashguard, in the form of a trapezoid having a long side adjacent the sliding plate  71 , a short side adjacent the first sliding door  65  and parallel to the X-axis, and oblique sides respectively adjacent the arcuate wall  74  and second sliding door  66 , may be used. In this case, a linear first sliding door (a preparation chamber side door) disposed at a part of the oblique side, adjacent the second sliding door  66 , forward of the partition wall  70 , and a linear second sliding door (a machining chamber side door) disposed adjacent the first linear sliding door rearward of the partition wall  70  so that each of the sliding doors linearly and obliquely moves backward independently for opening and closing. 
         [0036]    Alternatively, in  FIG. 4 , a rectangular splashguard, having a long side adjacent the sliding plate  71 , another long side adjacent the first sliding door  65  and parallel to the X-axis, and short sides respectively adjacent the arcuate wall  74  and second sliding door  66  and parallel to the X-axis, may be used. In this case, a linear first sliding door (a preparation chamber side door) disposed at a part of the short side, adjacent the second sliding door  66 , forward of the partition wall  70 , and a linear second sliding door (a machining chamber side door) disposed adjacent the first linear sliding door rearward of the partition wall  70  so that each of the sliding doors moves linearly and independently for opening and closing. 
         [0037]    The operation of the present embodiment and the interlock will be described below. 
         [0000]    (1) In Case that Only the First Sliding Door  65  is Opened 
         [0038]    When the B-axis is positioned at 0° or 180°, i.e., as shown in  FIG. 4 , when the double-faced workpiece mount  16  is at 90° relative to the rotational axis O of the spindle  26 , the interlock unlocks the locking mechanism of the first door locking switch  75 . This allows the first sliding door  65  to be opened. On the other hand, when the first sliding door  65  is opened, the interlock inhibits the rotation of the B-axis and maintains the position of the B-axis at 0° or 90°. This allows the operator to open the first sliding door  65  and access safely the preparation chamber  72  in order to demount a machined workpiece W from the mounting face  16   a  of the double-faced workpiece mount  16 , and mount a non-machined workpiece (not shown) to the mounting face whereby the workpieces are changed even when the spindle  26  of the machine tool  10  rotates to machine the workpiece W. When the first sliding door  65  is closed and the contact of the first door locking switch  75  is closed, the interlock allows the rotation of B-axis. 
         [0000]    (2) In Case that Only the Second Sliding Door  66  is Opened 
         [0039]    When the spindle  26 , the B-axis and the supply of the machining liquid are deactivated, the interlock unlocks the locking mechanism of the second door locking switch  76  whereby the second sliding door  66  can be opened. At that time, the unlock condition is satisfied if the B-axis is deactivated regardless of its rotational position. When the second sliding door  66  is opened, the interlock inhibits the rotations of the spindle  26  and the B-axis and the supply of the machining liquid. This allows an operator to open the second sliding door  66  safely and access the machining chamber  73  for operations, for example, manually changing tools, cleaning the machining chamber  73 , or debagging the machining process. When the second sliding door  66  is closed and the second door locking switch is closed, first, the interlock disengages the inhibition of the rotation of the B-axis. In this connection, it should be noted that, at that time, the first sliding door  65  is closed. Then when the B-axis is moved at 0° or 90° according to a command from for example the NC device, the interlock disengage the inhibition of the rotation of the spindle  26  and the supply of the machining liquid, i.e., these operations are allowed. 
         [0000]    (3) In Case that Both the First and Second Sliding Doors  65  and  66  are Opened at the Same Time 
         [0040]    When above-described conditions (1) and (2) are satisfied together, i.e., when the spindle  26 , B-axis and the supply of the machining liquid are deactivated and the B-axis is at 0° or 90°, the interlock unlocks the locking mechanism of the first door locking switch  75  at the same time the locking mechanism of the second door locking switch  76  is unlocked. This allows the first sliding door  65  to be opened in addition to allowing the second sliding door to be opened. When both the first and second sliding doors  65  and  66  are opened, the interlock inhibits the rotations of the spindle  26  and the B-axis and the supply of the machining liquid. When both the first and second sliding doors  65  and  66  are opened, although the first sliding door  65  cannot be singly closed, due to the configuration of the first and second sliding doors  65  and  66 , the second sliding door  66  can be singly closed. When the second sliding door  66  is closed and the first sliding door  65  is opened, the interlock disengages the inhibition of the rotation of the spindle  26  and the supply of the machining liquid to allow these operations to be activated. In this connection, it should be noted that the interlock inhibits the rotation of the B-axis when the first sliding door  65  is opened. 
         [0041]    As described above, the splashguard  61  of the machine tool  10  according to the embodiment, the front side first sliding door  65  and the lateral side second sliding door  66  can be separately opened and closed by the concentric arcuate movements, which allows selective open and close of the respective sliding doors as needed. Further, the machining region within the splashguard  61  is divided into the preparation chamber  72  and the machining chamber  73  by the double-faced workpiece mount  16 , mounted to the table  15  rotatable about B-axis, and the partition wall  70  disposed around the double-faced workpiece mount  16 . This configuration allows, when the workpiece W, mounted to one  16   b  of the workpiece mount faces of the double-faced workpiece mount  16 , preparation of a workpiece to the other  16   a  of the workpiece mount faces. 
         [0042]    The interlock, provided with the first and second door locking switches  75  and  76 , allows the front side first sliding door  65  to be singly opened and closed during machining for preparation of a workpiece W, allows the lateral side second sliding door  66  to be singly opened and closed for changing tool  72  manually, and allows the first and second sliding doors  65  and  66  to be fully opened by opening them together. Thus, according to the present embodiment, both or one of the first and second sliding doors  65  and  66  can be opened and closed while ensuring the safety of an operator. 
         [0043]    Further, the Y-axis servomotors  30  and the Y-axis ball screws  35  are disposed rear side of the bed body  13 , and the Y-axis servomotors  30  are connected to the lower ends of the Y-axis ball screws  35 . In the embodiment, the Y-axis guide rails  28 , the Y-axis servomotors  30  and the Y-axis ball screws  35  are disposed below the spindle head  25 . In particular, the Y-axis guide rails  28  extend so that their lower ends are positioned near the floor, and the servomotors  30  are also disposed adjacent the floor. As a result, the gravity center of the machine tool  10  can be lowered compared with conventional machine tools. Furthermore, higher stability of the machine tool  10  than ever before is realized by forming the vertically moving body  21  to have the bifurcated legs  22 , which accommodate the chip removing duct  53 , and by disposing guide blocks  29  to the legs  22  so as to support and guide the vertically moving body  21  with relatively long vertical span. Accordingly, the machining accuracy of the machine tool  10  can be increased. Further, the over-all height of the machine tool  10  can be reduced because the Y-axis servomotors  30  must not be disposed on the top of the machine tool  10 . 
         [0044]    The vertically moving body  21  may be configured to slide vertically along a pair of Y-axis guide rails  28  which may be disposed to extend vertically along the rear lateral sides of the bed  12 , which does not have the left and right side walls  14  extending rearwardly from the rear side of the bed body  13 , instead of the rear side of the bed body  13 . 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10  Machine Tool 
           12  Bed 
           14  Side Wall 
           15  Table 
           16  Double-Faced Workpiece Mount 
           16   a  Workpiece Mounting Face 
           16   b  Workpiece Mounting Face 
           21  Vertically Moving Body 
           22  Leg 
           23  Left-Right Moving Body 
           24  Font-Rear Moving Body 
           25  Spindle Head 
           26  Spindle 
           27  Tool 
           28  Y-axis Guide Rail 
           37  X-axis Guide Rail 
           43  Z-axis Guide Rail 
           61  Splashguard 
           62  Front Panel 
           63   a  Left Side Panel 
           63   a  Right Side Panel 
           64  Top Panel 
           65  First Sliding Door 
           66  Second Sliding Door 
           70  Partition Wall 
           71  Sliding Plate 
           72  Preparation Chamber 
           73  Machining Chamber 
           74  Arcuate Wall 
           75  First Door Locking Switch 
           76  Second Door Locking Switch