Patent Publication Number: US-2023146160-A1

Title: Machine tool

Description:
TECHNICAL FIELD 
     The present invention relates to a machine tool that retains a lathe machining tool using a tool holder installed on a spindle, and carries out machining, by the lathe machining tool, on an object to be machined that is placed on a rotary table. 
     BACKGROUND ART 
     JP 2018-034248 A discloses a machine tool that machines a workpiece by causing a spindle head to move relative to a table while rotating a spindle on which a cutting tool is mounted. 
     SUMMARY OF THE INVENTION 
     It is desirable to perform a turning process using the machine tool as disclosed in JP 2018-034248 A. The machine tool that carries out the turning process rotates the workpiece while the spindle on which a lathe machining tool is installed is non-rotatably fixed by stopping the operation of a motor. However, the spindle is originally configured in a manner so as to rotate. Therefore, in the machine tool that carries out the turning process, even if the spindle is fixed by the motor, the lathe machining tool that is in contact with the workpiece at the time of the turning process can easily move in the direction of rotation of the spindle. If the lathe machining tool moves during machining, the machining accuracy decreases. 
     Thus, an object of the present invention is to provide a machine tool that is capable of preventing a decrease in the accuracy of a turning process. 
     According to an aspect of the present invention, provided is a machine tool that retains a lathe machining tool using a tool holder installed on a spindle, and carries out machining, by the lathe machining tool, on an object to be machined that is placed on a rotary table, the machine tool including a fixing member configured to come into contact with the spindle or the tool holder to thereby disable rotation of the spindle and the tool holder. 
     According to the present invention, it is possible to prevent the accuracy of the turning process from being decreased. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a side view showing a machine tool according to a first embodiment of the present invention; 
         FIG.  2    is a side view showing a portion of the machine tool according to the first embodiment; 
         FIG.  3    is a bottom view showing a peripheral portion of a spindle of the machine tool according to the first embodiment; 
         FIG.  4    is a side view showing a portion of a machine tool according to second through fourth embodiments; 
         FIG.  5    is a side view showing a tool holder according to the second embodiment; 
         FIG.  6    is a side view showing the tool holder according to the third embodiment; 
         FIG.  7    is a side view showing the tool holder according to the fourth embodiment; 
         FIG.  8    is a side view showing a portion of a machine tool according to a fifth embodiment; 
         FIG.  9    is a side view of the tool holder and a plate according to the fifth embodiment; 
         FIG.  10    shows the tool holder and the plate according to an exemplary modification of the fifth embodiment; and 
         FIG.  11    is a side view showing a portion of a machine tool according to an exemplary modification of the second through fourth embodiments. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Preferred embodiments of a machine tool according to the present invention will be presented and described in detail below with reference to the accompanying drawings. 
     First Embodiment 
     A machine tool  10  according to a first embodiment will be described with reference to the drawings.  FIG.  1    is a side view showing the machine tool  10  according to the present embodiment. 
     The machine tool  10  carries out machining on an object to be machined  22 , in other words, a workpiece, by means of a lathe machining tool  18  that is mounted on a spindle  16 . 
     A spindle head  14  is provided on the machine tool  10 . The spindle  16  is provided on the spindle head  14 . A tool holder  20  for retaining the lathe machining tool  18  is detachably installed on the spindle  16 . 
     The machine tool  10  is equipped with a column  24  that causes the spindle head  14  to move in an upper/lower direction, an additional axis device  26  that rotatably supports the object to be machined  22 , and a table  34  that causes the additional axis device  26  to move in a first direction and a second direction. The spindle head  14  is supported by the column  24  via a support unit  15 . The first direction and the second direction are perpendicular to each other. The first direction is a Y direction and the second direction is an X direction. Further, a direction perpendicular to the Y direction and the X direction is defined as a Z direction. A downward direction in which gravity acts is a −Z direction, and an upward direction is a +Z direction. An axial direction of the spindle  16  is in parallel with the Z direction. 
     The additional axis device  26  is positioned below the spindle  16 . The additional axis device  26  is equipped with a rotary table  30 . The object to be machined  22  is fixed on the rotary table  30 . The object to be machined  22  can be fixed to the rotary table  30 , for example, by suction, but the present invention is not limited to this feature. The additional axis device  26  is equipped with a tilting mechanism  27  that tilts a rotary axis of the rotary table  30 . The rotary table  30  can be tilted at an arbitrary angle by the tilting mechanism  27 . The rotary axes that are added by the additional axis device  26  are a rotary axis that causes the rotary table  30  to rotate, and a rotary axis that causes the rotary table  30  to be tilted. More specifically, two rotary axes are added by the additional axis device  26 . 
     The machine tool  10  is capable of carrying out three dimensional machining on the object to be machined  22 , by moving the spindle  16  in the Z direction, moving the additional axis device  26  in the X direction and the Y direction, rotating the object to be machined  22  by the additional axis device  26 , and tilting the rotary table  30 . 
     The additional axis device  26  is supported by the table  34 . The table  34  is supported by a saddle  36 . The table  34  is equipped with a non-illustrated X-axis movement mechanism that causes the table  34  to move in the X direction with respect to the saddle  36 . Therefore, the table  34  is capable of moving in the X-axis direction with respect to the saddle  36 . The saddle  36  is supported by a bed  32 . The saddle  36  is equipped with a non-illustrated Y-axis movement mechanism that causes the saddle  36  to move in the Y-axis direction with respect to the bed  32 . Therefore, the saddle  36  is capable of moving in the Y-axis direction with respect to the bed  32 . In this manner, the table  34  is capable of moving in the X and Y directions with respect to the bed  32 . Mechanisms that are widely known can be used for the Y-axis movement mechanism and the X-axis movement mechanism. 
     A non-illustrated splash guard is provided on the machine tool  10 . The splash guard surrounds a machining area of the machine tool  10 . The splash guard serves to prevent cutting fragments including cutting chips, or a cutting fluid or the like, which are generated due to machining, from being scattered into the surrounding area. A non-illustrated nozzle through which the cutting fluid is discharged toward the lathe machining tool  18  during machining is provided in the machining area. The machine tool  10  according to the present embodiment is configured in the foregoing manner. 
       FIG.  2    is a side view showing a portion of the machine tool  10  according to the present embodiment.  FIG.  3    is a bottom view showing a peripheral portion of the spindle  16  of the machine tool  10  according to the present embodiment. 
     The tool holder  20  retains the lathe machining tool  18  and is installed on the spindle  16 . A turning tip  18   a , and more specifically, a cutting edge is provided, for example, on a distal end part of the lathe machining tool  18 . The spindle  16  is connected to an output shaft of a non-illustrated motor. Two spindle keys  40  that project out in the −Z direction are formed at an end of the spindle  16  in the −Z direction. The two spindle keys  40  are arranged in opposite directions with respect to the tool holder  20 . The spindle  16  is stopped in a manner so that the two spindle keys  40  and the tool holder  20  are arranged alongside one another in the Y direction. 
     In addition to the spindle  16 , a block  42  is provided on the spindle head  14 . The block  42  is arranged in the −Y direction of the spindle  16  and extends in the −Z direction from the spindle head  14 . The block  42  is a member disposed in parallel with the XZ plane. The block  42  includes one pair of gripping members (fixing members)  44  arranged in parallel with each other. The pair of gripping members  44  are fixed by non-illustrated bolts or the like to the block  42 . The pair of gripping members  44  extend in a direction that intersects the spindle  16 . An interval between one of the gripping members  44  and the other of the gripping members  44  is substantially the same as the width of the spindle key  40 . The one of the gripping members  44  contacts one side surface  40   a  of the spindle key  40 , and the other of the gripping members  44  contacts another side surface  40   b  of the spindle key  40 . In other words, the pair of gripping members  44  grip the spindle key  40 , which is arranged in close proximity to the block  42 , from one and the other directions of rotation R of the spindle  16 . 
     In the present embodiment, the pair of gripping members  44 , which are connected to the spindle head  14  via the block  42 , grip the spindle key  40 , and thereby disable the movement of the spindle key  40  in the directions of rotation R. Upon doing so, the tool holder  20  and the lathe machining tool  18  become incapable of rotating in the directions of rotation R together with the spindle  16 . Accordingly, even if the object to be machined  22  rotates during the turning process, the lathe machining tool  18  does not move. In this manner, according to the present embodiment, since the spindle  16  is firmly fixed and does not move, it is possible to prevent the accuracy of the turning process from being decreased due to a shifting in position of the lathe machining tool  18 . 
     Second Embodiment 
     A machine tool  10  according to a second embodiment will be described with reference to  FIG.  4    and  FIG.  5   .  FIG.  4    is a side view showing a portion of the machine tool  10  according to the present embodiment.  FIG.  5    is a side view showing the tool holder  20  according to the present embodiment. The same constituent elements as those of the machine tool  10  according to the first embodiment are designated by the same reference numerals, and description thereof will be omitted or referred to in an abbreviated manner. 
     A hole  50  serving as a concave portion (a first fitting portion) is formed in an outer peripheral surface  20   a  of the tool holder  20 . The spindle  16  is stopped in a manner so that the hole  50  faces in a direction of the block  42 , namely, the −Y direction. The block  42  is equipped with a pin (a fixing member)  52  serving as a convex portion (a second fitting portion). The pin  52  is fixed by a non-illustrated bolt or the like to the block  42 . The pin  52  extends in a direction that intersects the tool holder  20 . The diameter of the pin  52  and the diameter of the hole  50  are substantially the same. A distal end of the pin  52  is fitted into the hole  50 . Upon doing so, the distal end of the pin  52  comes into contact with an inner circumferential surface of the hole  50 . 
     According to the present embodiment, by the pin  52  that is connected via the block  42  to the spindle head  14  being fitted into the hole  50  of the tool holder  20 , movement of the tool holder  20  in the directions of rotation R is disabled. Upon doing so, the spindle  16  and the lathe machining tool  18  become incapable of rotating in the directions of rotation R together with the tool holder  20 . Accordingly, even if the object to be machined  22  rotates during the turning process, the lathe machining tool  18  does not move. In this manner, according to the present embodiment, since the tool holder  20  is firmly fixed and does not move, it is possible to prevent the accuracy of the turning process from being decreased due to a shifting in position of the lathe machining tool  18 . 
     Third Embodiment 
     A machine tool  10  according to a third embodiment will be described with reference to  FIG.  4    and  FIG.  6   .  FIG.  6    is a side view showing the tool holder  20  according to the present embodiment. The same constituent elements as those of the machine tools  10  according to the first embodiment and the second embodiment are designated by the same reference numerals, and description thereof will be omitted or referred to in an abbreviated manner. 
     A groove  60  serving as a concave portion (a first fitting portion) is formed on the outer peripheral surface  20   a  of the tool holder  20 . The spindle  16  is stopped in a manner so that the groove  60  faces in a direction of the block  42 , namely, the −Y direction. The groove  60  is formed in a manner so that a centerline C 1  of the groove  60  is in parallel with an axis A of the tool holder  20 . The groove  60  is formed from an upper end of the tool holder  20  to substantially a central portion of the tool holder  20 . An opening  62  is formed at an upper end of the groove  60 , and a stop  64  is formed at a lower end of the groove  60 . The opening  62  is provided in order to guide the pin  52  from the exterior to the interior of the groove  60 . The diameter of the pin  52  and the width of the groove  60  are substantially the same. 
     The distal end of the pin  52  is fitted into the groove  60  in the following manner. In a state in which the pin  52  faces toward the axis A of the tool holder  20 , the distal end of the pin  52  is inserted from above into the opening  62 . Subsequently, the pin  52  or the tool holder  20  is moved in a manner so that the distal end of the pin  52  moves along the groove  60  toward the stop  64 . When the distal end of the pin  52  comes into contact with the stop  64 , the movement of the pin  52  or the tool holder  20  is stopped. In this state, the distal end of the pin  52  comes into contact with both inner wall surfaces  66  that face toward each other and the stop  64 . For example, a non-illustrated ATC (automatic tool changer) installs the tool holder  20  on the spindle  16  from below. At this time, the distal end of the pin  52  is fitted into the groove  60 . 
     According to the present embodiment, by the pin  52  that is connected via the block  42  to the spindle head  14  being fitted into the groove  60  of the tool holder  20 , movement of the tool holder  20  in the directions of rotation R is disabled. Upon doing so, the spindle  16  and the lathe machining tool  18  become incapable of rotating in the directions of rotation R together with the tool holder  20 . Accordingly, even if the object to be machined  22  rotates during the turning process, the lathe machining tool  18  does not move. In this manner, according to the present embodiment, since the tool holder  20  is firmly fixed and does not move, it is possible to prevent the accuracy of the turning process from being decreased due to a shifting in position of the lathe machining tool  18 . 
     Fourth Embodiment 
     A machine tool  10  according to a fourth embodiment will be described with reference to  FIG.  4    and  FIG.  7   .  FIG.  7    is a side view showing the tool holder  20  according to the present embodiment. The same constituent elements as those of the machine tools  10  according to the first embodiment through the third embodiment are designated by the same reference numerals, and description thereof will be omitted or referred to in an abbreviated manner. 
     A groove  70  serving as a concave portion (a first fitting portion) is formed on the outer peripheral surface  20   a  of the tool holder  20 . The spindle  16  is stopped in a manner so that the groove  70  faces in a direction of the block  42 , namely, the −Y direction. The groove  70  is formed in a manner so that a centerline C 2  of the groove  70  is in parallel with the axis A of the tool holder  20 . The groove  70  is formed from an upper end of the tool holder  20  to a lower end of the tool holder  20 . A first opening  72  is formed at an upper end of the groove  70 , and a second opening  74  is formed at a lower end of the groove  70 . The first opening  72  is provided in order to guide the pin  52  from the exterior to the interior of the groove  70 . The width of the groove  70  at the first opening  72  is greater than the diameter of the pin  52 . On the other hand, the width of the groove  70  at the second opening  74  is less than the diameter of the pin  52 . In other words, the groove  70  is formed in a tapered shape in which an interval between inner wall surfaces  76  thereof gradually decreases from the first opening  72  toward the second opening  74 . 
     The distal end of the pin  52  is fitted into the groove  70  in the following manner. In a state in which the pin  52  faces toward the axis A of the tool holder  20 , the distal end of the pin  52  is inserted from above into the first opening  72 . Subsequently, the pin  52  or the tool holder  20  is moved in a manner so that the distal end of the pin  52  moves along the groove  70  toward the second opening  74 . When the distal end of the pin  52  comes into contact with both of the inner wall surfaces  76 , the movement of the pin  52  or the tool holder  20  is stopped. In this state, the distal end of the pin  52  comes into contact with both of the inner wall surfaces  76  that face toward each other. For example, a non-illustrated ATC (automatic tool changer) installs the tool holder  20  on the spindle  16  from below. At this time, the distal end of the pin  52  is fitted into the groove  70 . 
     According to the present embodiment, in the same manner as the third embodiment, it is possible to prevent the accuracy of the turning process from being decreased due to a shifting in position of the lathe machining tool  18 . 
     Fifth Embodiment 
     A machine tool  10  according to a fifth embodiment will be described with reference to  FIG.  8    and  FIG.  9   .  FIG.  8    is a side view showing a portion of the machine tool  10  according to the present embodiment.  FIG.  9    is a side view of the tool holder  20  and a plate  82  according to the present embodiment. The same constituent elements as those of the machine tools  10  according to the first embodiment through the fourth embodiment are designated by the same reference numerals, and description thereof will be omitted or referred to in an abbreviated manner. 
     A groove  80  serving as a concave portion (a first fitting portion) is formed in the outer peripheral surface  20   a  of the tool holder  20 . The spindle  16  is stopped in a manner so that the groove  80  faces in a direction of the block  42 , namely, the −Y direction. The groove  80  is formed along the directions of rotation R of the tool holder  20 . The groove  80  is formed in a rectangular shape in an XY cross section of the tool holder  20 . The block  42  is equipped with a plate (a fixing member)  82  serving as a convex portion (a second fitting portion). The plate  82  is fixed by a non-illustrated bolt or the like to the block  42 . The plate  82  extends in a direction that intersects the tool holder  20 . A distal end of the plate  82  is formed in a rectangular shape that is fitted into the groove  80 . 
     According to the present embodiment, by the plate  82  that is connected via the block  42  to the spindle head  14  being fitted into the groove  80  of the tool holder  20 , movement of the tool holder  20  in the directions of rotation R is disabled. Therefore, according to the present embodiment, in the same manner as the first through fourth embodiments, it is possible to prevent the accuracy of the turning process from being decreased due to a shifting in position of the lathe machining tool  18 . 
     Moreover, as shown in  FIG.  10   , the tool holder  20  may have a prismatic shape having a rectangular XY cross section. 
     Exemplary Modifications 
     A description will be given with reference to  FIG.  11    concerning the machine tool  10  according to an exemplary modification of each of the embodiments.  FIG.  11    is a side view showing a portion of the machine tool  10  according to the exemplary modification of the second through fourth embodiments. The same constituent elements as those of the machine tool  10  according to the second embodiment are designated by the same reference numerals, and description thereof will be omitted or referred to in an abbreviated manner. 
     The block  42  supports the pin  52  via a movement mechanism  90 . The movement mechanism  90  is equipped with a hydraulic or an electric drive system. By causing the pin  52  to move in a direction toward the tool holder  20  (in the Y direction in  FIG.  11   ), the movement mechanism  90  inserts the distal end of the pin  52  into the hole  50  (see  FIG.  5   ) or the groove  60  (see  FIG.  6   ) or the groove  70  (see  FIG.  7   ). Further, by causing the pin  52  to move in a direction away from the tool holder  20  (in the −Y direction in  FIG.  11   ), the movement mechanism  90  pulls out the distal end of the pin  52  from the hole  50  (see  FIG.  5   ) or the groove  60  (see  FIG.  6   ) or the groove  70  (see  FIG.  7   ). 
     The movement mechanism  90  is also capable of causing the gripping members  44  of the first embodiment or the plate  82  of the fifth embodiment to move in the directions toward and away from the tool holder  20 . 
     Furthermore, various exemplary modifications may be considered in relation to the respective embodiments described above. For example, in the second to fourth embodiments described above, the tool holder  20  is formed with the concave portion and the pin  52  is formed with the convex portion. Instead of this feature, the tool holder  20  may be formed with the convex portion and the distal end of the pin  52  may be formed with the concave portion. Further, in each of the embodiments, the block  42  may be provided on the support unit  15  instead of the spindle head  14 . 
     In the third embodiment, the groove  60  may be formed in a manner so that an interval between both of the inner wall surfaces  66  thereof gradually decreases from the outer peripheral surface  20   a  side toward the axis A side. Similarly, in the fourth embodiment, the groove  70  may be formed in a manner so that an interval between both of the inner wall surfaces  76  thereof gradually decreases from the outer peripheral surface  20   a  side toward the axis A side. In this case, the distal end of the pin  52  is preferably formed in a tapered shape. 
     Inventions that can be Obtained from the Embodiments 
     The inventions that are capable of being grasped from the above-described embodiments will be described below. 
     The aspect of the present invention is characterized by the machine tool ( 10 ) that retains the lathe machining tool ( 18 ) using the tool holder ( 20 ) installed on the spindle ( 16 ), and that carries out machining, by the lathe machining tool, on the object to be machined ( 22 ) that is placed on the rotary table ( 30 ), the machine tool including the fixing member ( 44 ,  52 ,  82 ) that comes into contact with the spindle or the tool holder to thereby disable rotation of the spindle and the tool holder. 
     In the aspect of the present invention, there may further be provided the spindle head ( 14 ) equipped with the spindle, and the block ( 42 ) fixed to the spindle head, wherein the fixing member may extend from the block in a direction intersecting the spindle. 
     In the aspect of the present invention, there may further be provided the spindle key ( 40 ) that projects out from a portion of the spindle toward the side of the lathe machining tool, wherein the fixing member may disable rotation of the spindle by gripping the spindle key from one direction of rotation (R) and another direction of rotation (R) of the spindle. 
     In the aspect of the present invention, the tool holder may include the first fitting portion ( 50 ,  60 ,  70 ,  80 ), the fixing member may include the second fitting portion ( 52 ,  82 ), and rotation of the tool holder may be disabled by the first fitting portion and the second fitting portion being fitted to each other. 
     In the aspect of the present invention, the first fitting portion may be the concave portion ( 50 ,  60 ,  70 ,  80 ) formed on the outer peripheral surface ( 20   a ) of the tool holder, and the second fitting portion may be the convex portion ( 52 ,  82 ) formed at the distal end of the fixing member. 
     In the aspect of the present invention, the concave portion may be the hole ( 50 ), and the convex portion may be the pin ( 52 ). 
     In the aspect of the present invention, there may further be provided the movement mechanism ( 90 ) that causes the fixing member to move in directions toward and away from the tool holder. 
     In the aspect of the present invention, the concave portion may be the groove ( 60 ,  70 ) that is formed in parallel with the axis (A) of the tool holder, and the convex portion may be the pin ( 52 ). 
     In the aspect of the present invention, the groove may be open on the side of the lathe machining tool. 
     In the aspect of the present invention, the groove may be closed on the side of the spindle, and the pin may come into contact with the spindle side end part ( 64 ) of the groove. 
     In the aspect of the present invention, the groove may be formed in a tapered shape in which the width thereof gradually narrows from the side of the spindle toward the side of the lathe machining tool, and the pin may come into contact with the inner wall surfaces ( 76 ) of the groove. 
     It should be noted that the machine tool according to the present invention is not limited to the embodiments described above and the exemplary modifications thereof, and it is a matter of course that various configurations could be adopted therein without departing from the essence and gist of the present invention.