Abstract:
A tool changer includes at least one tool changer unit, wherein the at least one tool changer unit includes: a tool holder that receives and holds a tool; a base member that supports the tool holder so that the tool holder can be slid along a longitudinal direction of the tool; and a moving mechanism that slides the tool holder relative to the base member.

Description:
[0001]    Japanese Patent Application No. 2016-086007 filed on Apr. 22, 2016, is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The present invention relates to a tool changer that is used for a machine tool, and the like. In particular, the invention relates to a tool changer, a machine tool, and a method for changing a tool that are suitable for a long tool (i.e., a tool of long length). 
         [0003]    A machine tool (e.g., lathe and multi-tasking machine) that utilizes a plurality of tools is provided with an auto tool changer (ATC) unit that includes an ATC and a tool magazine. 
         [0004]    However, the tool magazine included in the ATC unit is normally limited as to the length of the tool that can be received therein in order to provide a number of tools. 
         [0005]    A long tool may be required to work a long workpiece. The invention was conceived as a result of conducting studies with regard to a tool changer that is suitable for a long tool. 
         [0006]    JP-A-2005-103650 discloses a tool changer that includes a tool support plate that positions and holds a tool in a laid-down state, and approximately extends in a horizontal plane. 
         [0007]    However, since the structure disclosed in JP-A-2005-103650 is characterized in that a long tool is moved horizontally in a transverse direction that is orthogonal to the longitudinal direction of the long tool, a large receiving space is required for the tool changer, and it is difficult to conserve space. 
       SUMMARY 
       [0008]    An object of the invention is to provide a tool changer, a machine tool, and a method for changing a tool that make it possible to receive a long tool using a small space, and deal with tools that differ in length. 
         [0009]    According to one aspect of the invention, there is provided a tool changer comprising: 
         [0010]    at least one tool changer unit, 
         [0011]    wherein the at least one tool changer unit comprises: 
         [0012]    a tool holder that receives and holds a long tool; 
         [0013]    a base member that supports the tool holder so that the tool holder can be slid along a longitudinal direction of the long tool; and 
         [0014]    a moving mechanism that slides the tool holder relative to the base member. 
         [0015]    The tool changer may comprise: 
         [0016]    a plurality of the tool changer units that are provided parallel to each other in the longitudinal direction. 
         [0017]    Since the long tool is held so that it can be slid in the longitudinal direction, it is possible to conserve the receiving space with respect to the tool changer. 
         [0018]    It is possible to implement an auto tool changer by automatically controlling the slide movement of the tool holder. 
         [0019]    In the tool changer, 
         [0020]    wherein the tool holder may comprise a holding member that sandwiches and holds the long tool when the long tool is moved downward, and may release the long tool when the long tool is moved upward. 
         [0021]    In the tool changer, 
         [0022]    wherein the holding member may comprise a pair of clamp arms that are open on an upper side, and the pair of clamp arms are biased in a direction in which the pair of clamp arms are closed. 
         [0023]    According to this configuration, since it is possible to hold and release the long tool using the holder by merely moving the long tool upward and downward, it is unnecessary to drive the holder using a drive source. 
         [0024]    Note that only one tool holder may be provided corresponding to one tool or a plurality of tools. 
         [0025]    In the tool changer, 
         [0026]    wherein the holding member may be moved forward along the longitudinal direction toward a delivery position at which the tool is delivered, and 
         [0027]    the holding member may be provided at a front end of the tool holder in a forward moving direction. 
         [0028]    According to this configuration, it is possible to stop the tool holder at a constant forward position or backward position, and hold the tool using the holder, irrespective of the length of the tool. Therefore, it is unnecessary to change the forward position or the backward position corresponding to the length of the tool. 
         [0029]    The tool changer according to one aspect of the invention can deal with a tool having a standard length, and can also deal with a long tool having a length of  300  mm or more, for example. 
         [0030]    The tool changer may further comprise: 
         [0031]    a shutter that is opened and closed along a direction that intersects a forward moving path of the tool holder, 
         [0032]    wherein the holding member may protrude outward from an opening-closing position of the shutter when set to the delivery position of the tool. 
         [0033]    Since the tool holder that is moved along the longitudinal direction of the tool can deliver the tool by placing the tool at a position outward from the opening-closing position of the shutter, it is possible to conserve space. 
         [0034]    According to another aspect of the invention, there is provided a machine tool comprising the above tool changer. 
         [0035]    The shutter separates the working area from an area other than the working area when used for the machine tool that includes the tool changer, and the tool changer unit may be provided in an area other than the working area. 
         [0036]    In this case, since a tool that is not used for working is received in an area other than the working area, the tool is not exposed to chips and the like. 
         [0037]    The tool changer unit may include a means that blows air to the tool that has been returned to an area other than the working area. 
         [0038]    The machine tool that utilizes the tool changer described above can automatically change a tool by controlling the movement of the tool rest to which the tool shaft is provided so as to be turnable. 
         [0039]    According to still another aspect of the invention, there is provided a method for changing a tool comprising: 
         [0040]    opening a shutter; 
         [0041]    selecting one tool changer unit that holds a desired tool from a plurality of tool changer units; 
         [0042]    moving a tool holder of the selected one tool changer unit forward along a longitudinal direction of a tool that is held by the tool holder to place a front end of the tool at a position outward from the shutter; 
         [0043]    moving a tool rest toward the tool, and causing a tool shaft that is provided to the tool rest to chuck the tool; and 
         [0044]    moving the tool rest upward to remove the tool from the tool holder. 
         [0045]    In this case, a sensor that detects whether or not a tool is being clamped may be provided to each tool changer unit. 
         [0046]    Since the tool changer, the machine tool, and the method for changing a tool according to the invention hold the long tool so that it can be slid in the longitudinal direction, it is possible to directly receive and deliver the long tool using the tool shaft in a state in which the shank of the tool protrudes into the working area of the machine tool. 
         [0047]    This makes it possible to provide the tool changer according to the invention in the space of the machine tool (e.g., a space around the main spindle of a multi-tasking machine that chucks a workpiece). Therefore, it is possible to conserve space, and achieve high efficiency. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0048]      FIG. 1A  is an external view illustrating a tool changer according to one embodiment of the invention in a state in which each tool (long tool) is placed at a backward position,  FIG. 1B  is an external view illustrating a tool changer according to one embodiment of the invention in a state in which a tool T 1  has been moved forward, and  FIG. 1C  is an external view illustrating a tool changer according to one embodiment of the invention in a state in which a tool T 2  has been moved forward. 
           [0049]      FIGS. 2A to 2D  schematically illustrate a flow in which a tool is delivered to a tool shaft that is provided to a tool rest. 
           [0050]      FIGS. 3A to 3C  illustrate an example (motion) in which a tool is received and held by a holding member. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0051]    An example of the structure of a tool changer according to the exemplary embodiments of the invention is described below with reference to the drawings. Note that the invention is not limited thereto. 
         [0052]      FIGS. 1A to 1C  are external views illustrating a tool changer  10 . 
         [0053]      FIGS. 1A to 1C  illustrate an example in which three tool changer units are provided parallel to each other. An arbitrary number of tool changer units may be provided. 
         [0054]    Common reference signs and numbers are used for each tool changer unit. 
         [0055]    The tool changer unit includes a base member  11 , and a tool holder  12  that is slidable relative to the base member  11  along the longitudinal direction of a tool T. The tool holder  12  moves forward in the forward direction F and backward in the backward direction B as illustrated in  FIG. 1A  along the longitudinal direction of the tool T. 
         [0056]    A clamp  14  (holding member) that holds the tool T is provided to the front end of the tool holder  12  in the forward direction F. 
         [0057]    In the example illustrated in  FIGS. 1A to 1C , a linear motion (LM) guide that includes an LM rail  11   a  and an LM block  12   a  is used as a slide moving mechanism, and a rod  13   a  of an air cylinder  13  (drive source) is connected to the rear end of the tool holder  12  in the forward direction F. 
         [0058]    The tool holder  12  is configured so that a case  17  is supported by the upper part of brackets  17   a  to  17   c  that are vertically provided on each side of the tool holder  12 , and the tool T is received in the space formed under the case  17 . 
         [0059]    A sensor  18  that detects whether or not the tool T is present, an air blow nozzle (not illustrated in the drawings), and the like are provided inside the case  17 . 
         [0060]    The sensor  18  is used to check whether or not the tool T is being held by the tool holder  12 , and the air blow nozzle is used to remove chips and the like from the tool T that has been returned to the tool changer unit by blowing air. 
         [0061]    A flexible pedestal  15  may be provided to movably hold a cable and a pipe connected to the sensor  18  and the air blow nozzle. 
         [0062]    A Cableveyor (registered trademark) may be used as the flexible pedestal  15 , for example. The flexible pedestal  15  is configured so that a cable and the like are supported and guided between a moving end  15   a  (that is connected to the case  17  that moves) and a fixed end  15   b , while the position of the U-shaped bent part changes so as to maintain a constant radius, for example. The fixed end  15   b  of the flexible pedestal  15  is secured using a bracket (not illustrated in the drawings). A proximity dock  16  is provided to the flexible pedestal  15 . An air cylinder  13  is driven by a proximity switch and a control section (not illustrated in the drawings), and stopped at the forward position (tool delivery position) and the backward position (tool reception position) of the tool holder  12 . 
         [0063]      FIG. 3A  illustrates an example of the structure of the holding member  14  (clamp) that holds the tool T. 
         [0064]    The clamp  14  includes right and left clamp arms  14   a  that make a pair and are rotatably provided to a bracket (not illustrated in the drawings) secured on the tool holder  12  using shafts  14   b . The clamp arms  14   a  are biased by a spring material  14   c  in the direction in which the clamp arms  14   a  are closed (i.e., the direction in which the upper opening becomes narrow). 
         [0065]    When the tool T that is situated above the clamp  14  is moved downward, clamping sections  14   d  are pressed outward by the outer circumferential part of the tool T against the biasing force indicated by the arrows (see  FIG. 3B ). 
         [0066]    When the tool T is further moved downward, the tool T is sandwiched and held between the arc-shaped clamping sections  14   d  (see  FIG. 3C ). 
         [0067]    Note that the tool T is removed by performing the above steps in reverse order. 
         [0068]    A step that delivers the tool to a tool shaft  21  of a tool rest  20  is described below with reference to  FIGS. 2A to 2D . 
         [0069]      FIGS. 2A to 2D  illustrate the motion of the tool T, and the case  17  and the brackets  17   a  to  17   c  of the tool changer unit, the flexible pedestal  15 , and the like are omitted. 
         [0070]    The tool shaft  21  chucks the tool T that is used for machining. The tool shaft  21  is provided to the tool rest  20  in a state in which the tool shaft  21  can be turned. 
         [0071]    The tool rest  20  is moved in the working area in an X-axis direction, a Y-axis direction, and a Z-axis direction that are orthogonal to each other. 
         [0072]    An area  30  in which the tool changer  10  is placed is separated by a shutter  31  of the tool changer  10  from the working area in which the tool rest  20  is placed. 
         [0073]    When the tool shaft  21  has approached the shutter  31  (see  FIG. 2A ), the shutter  31  is opened by the control section (not illustrated in the drawings) in synchronization with the approach motion, is driven (see  FIG. 2B ), and the tool holder  12  is moved forward to a given forward position by operating the air cylinder  13 . In this case, the forward position (tool delivery position) of the tool holder  21  may be set to a constant position irrespective of the length of the tool T. When the tool changer  10  includes a plurality of tool changer units, one tool changer unit that holds the desired tool is selected by the control section from the plurality of tool changer units, and the tool holder  12  included in the selected tool changer unit is moved forward. 
         [0074]    The tool shaft  21  then chucks the shank of the tool T (see  FIG. 2B ) under control of the control section (not illustrated in the drawings). 
         [0075]    When the tool rest  20  is moved upward (see  FIG. 2C ) under control of the control section (not illustrated in the drawings), the tool T is removed from the clamp  14 . 
         [0076]    The tool T is thus delivered to the tool shaft  21  (see  FIG. 2D ). As illustrated in  FIGS. 2A to 2D , since only the front end of the tool T protrudes from the shutter  31  into the working area, and the rear end of the tool T remain in the area  30  other than the working area, it is possible to reduce the space within the working area that required to deliver the tool T to the tool shaft  21  from the tool holder  12 . 
         [0077]    Note that the tool T is returned to the tool changer  10  from the tool shaft  21  by performing the above steps in reverse order. In this case, the backward position (tool reception position) of the tool holder  21  may be set to a constant position irrespective of the length of the tool T. 
         [0078]    Although only some embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.