Abstract:
In a cover structure of a robot, the robot includes two or more movable portions, is stored in a cover, and is mounted with an end effector in any one of the two or more movable portions. The cover is fixed to any one of the movable portions other than the movable portion mounted with the end effector among the two or more movable portions, and has a cover opening portion where the end effector is capable of passing.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a cover structure of a robot. 
         [0003]    2. Description of the Related Art 
         [0004]    A robot is used to carry a workpiece into a machine tool and to carry out the machined workpiece from the machine tool. A structure which protects the robot from a chip or a machining fluid is required in a case where the robot is used in an environment, such as a machining area of the machine tool, where the chip or the machining fluid scatters. For example, in a case where the robot automatically exchanges the workpiece of the machine tool, a system is generally configured such that a door separating the robot and the machining area is provided, the door is closed during machining, and the robot enters the machining area to exchange the workpiece when the door is opened after machining (see JP 2010-36285 A). 
         [0005]    The door is necessary to be automatically opened and closed, and thus it is necessary to additionally prepare an actuator such as an air cylinder and to provide a control device such as an electromagnetic valve for driving the air cylinder through an electric signal sent from the robot or the machine tool. In addition, there is a risk that the robot collides with the door in a case where an erroneous operation occurs or the robot is operated more quickly than the opening/closing speed of the door. 
         [0006]    In addition, a method in which the door is directly opened and closed by a hand of the robot can be adopted as another method of opening and closing the door. The actuator for opening and closing is not required in this case, but the method is not suitable for a high-speed motion by reason of the time loss according to an increase of the operation of the robot. In addition, there is still a possibility that an erroneous motion causes the robot to collide with the door. 
         [0007]      FIGS. 1A and 1B  illustrate a robot  1 , which automatically exchanges a workpiece  13  mounted in a workpiece table  11  of a machine tool  7 , and a structure of a door  4 , which is automatically opened and closed, as an example of a conventional technology. The robot  1  is provided on an operation area A side, and includes an end effector  2  gripping the workpiece  13  at a fingertip. The operation area A and a machining area B are partitioned by a fixed wall  5 . The door  4  is attached to the fixed wall  5 , and is configured as an automatic door which can be opened and closed by an air cylinder  3 . The machining area B of the machine tool  7  is blocked from the outside by the fixed wall  5  and the door  4 . 
         [0008]    The mechanical configuration of the machine tool  7  which machines the workpiece  13  is disposed in the machining area B. A tool main axis  9  is attached to a machine tool axis  8 . Then, a tool  10  is mounted in the tool main axis  9 . Reference numeral  12  indicates a scattered chip or cutting liquid  12  scattered when the workpiece  13  is machined. It is prevented that the chip or the cutting liquid is scattered toward the robot  1  in such a manner that the door  4  is closed as illustrated in  FIG. 1A  while the machine tool  7  machines the workpiece  13 . 
         [0009]    The door  4  is opened, and the robot  1  enters the machining area B as illustrated in  FIG. 1B  when the workpiece is exchanged after completing the machining. The air cylinder  3  is attached to the door  4 , and air is supplied thereto (the device for supplying the air and the like are not illustrated) to open and close the door  4 . A signal for opening and closing the door  4  is output from a control device (not illustrated) of the robot  1  or the control device (not illustrated) of the machine tool  7 . For example, the electromagnetic valve (not illustrated) is controlled with the signal to switch the air to be supplied to the air cylinder  3  between ON and OFF. 
         [0010]    A collision between an arm portion of the robot  1  and the door  4  occurs when the arm portion of the robot  1  enters the machining area B before the door  4  completely opens. It is necessary that a door detection sensor  6  perceiving an opening/closing state of the door  4  and the like are attached to limit the operation range of the robot  1  in order to prevent the collision. 
         [0011]    In addition, there is also a method in which, for example, the robot  1  grips the door  4  with the end effector  2  to directly open the door  4  without using the actuator such as the air cylinder  3 . This case does not require the actuator for opening and closing the door. However, a motion of opening and closing the door  4  is added so that it takes more time for the robot  1  to exchange the workpiece  13 , and thus efficiency is decreased. This case also has a possibility that the erroneous operation occurs or the robot  1  is failed to open and close the door  4 , and thus it is necessary that the door detection sensor  6  perceiving the opening/closing state of the door  4  and the like are attached to limit the operation range of the robot  1  in order to reduce the risk that the robot  1  collides with the door  4 . 
       SUMMARY OF THE INVENTION 
       [0012]    In this regard, the invention has been made inconsideration of the above problem of the relate art, and an object thereof is to provide a cover structure of a robot in which the robot can be protected from a generation source of a contamination material to contaminate the robot by fixing the cover to a movable portion of the robot. 
         [0013]    In a cover structure of a robot according to the invention, the robot includes two or more movable portions, is stored in a cover, and is mounted with an end effector in any one of the two or more movable portions. The cover is fixed to any one of the movable portions other than the movable portion mounted with the end effector among the two or more movable portions, and has a cover opening portion where the end effector is capable of passing. 
         [0014]    According to the invention, a position or a direction of the cover can be optionally changed through a posture of the robot by fixing the cover to the movable portion of the robot. The cover can be disposed in a position or a direction for protecting the robot therefrom since the generation source of the chip or the cutting liquid is determined. 
         [0015]    The robot may be a vertical articulated robot. The robot is the vertical articulated robot so that the robot has a high freedom degree of operation range, and the position or the direction of the cover is changed in a wide range. 
         [0016]    The cover may be attached to a rotating axis as the movable portion of a base portion of the vertical articulated robot. The cover having an opening portion is attached to the rotating axis (axis J 1 ) of the base portion of the robot so that a relative relation of the opening portion with respect to axes (axes J 2  to J 6 ) above the axis J 1  is not changed, and thus the robot can operates in a wide range without an interference with the cover. 
         [0017]    The cover may have a rotationally symmetric shape having substantially the same center as a rotational center of the rotating axis, a fixed wall may be disposed outside a rotation trajectory of the cover, the fixed wall may include a fixed wall opening portion, and the cover may be disposed so as to block the fixed wall opening portion. According to the invention, the fixed wall is disposed outside the rotationally-symmetric shaped cover, and thus the area where the robot operates can be freely selected among the plurality of areas separated by the fixed wall through the angle of the rotating axis (J 1 ). 
         [0018]    The fixed wall may be formed of at least one surface extending radially from substantially the same central axis as the rotational center of the rotating axis, and the cover opening portion may face any one of a plurality of areas partitioned by the surface. According to the invention, an area is partitioned into only two areas in a case where the fixed wall is a simple plan surface, but the area can be partitioned into three or more areas in the case of a radial-shaped wall. For example, the area can be partitioned into four areas when the four fixed walls are disposed at intervals of a ninety degree angle radially with respect to the rotating axis. The radial-shaped fixed wall can allow the operation range of the robot to widen with respect to the rotation angle of J 1 . For example, when a cover  20  has a cylindrical shape, and the opening portion of the cylindrical surface thereof has a thirty degree angle, the operation can be performed in ±30 freedom degrees of the rotating axis J 1  in each area partitioned at intervals of the ninety degree angle, and the area is separated from the other areas, where the operation is not performed during the operation, by the fixed wall  5  and the cover  20 . 
         [0019]    Another cover blocking the cover opening portion may be attached to a movable portion other than the movable portion attached with the cover. According to the invention, the another cover serving as a lid of the cover opening portion is attached to the movable portion of the robot, and thus the lid (another cover) can be opened and closed according to the posture of the robot. 
         [0020]    According to the invention, the cover structure of the robot can be provided in which the robot can be protected from the generation source of the contamination material to contaminate the robot by fixing the cover to the movable portion of the robot. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The above object, other objects, and features of the invention will become clear through the description of the following embodiments with reference to the accompanying drawings as follows: 
           [0022]      FIG. 1A  is a diagram illustrating a robot which automatically exchanges a workpiece of a machine tool and a structure of a door which is automatically opened and closed, and a diagram illustrating a state where an automatic door is closed; 
           [0023]      FIG. 1B  is a diagram illustrating the robot which automatically exchanges the workpiece of the machine tool and the structure of the door which is automatically opened and closed, and a diagram illustrating a state where the automatic door is opened; 
           [0024]      FIG. 2  is a diagram illustrating an embodiment in which the robot can be protected from a chip or a cutting liquid scattered from a back surface; 
           [0025]      FIG. 3A  is a diagram illustrating a state where the robot is operated on an operation area A side in a configuration illustrated in  FIG. 2 ; 
           [0026]      FIG. 3B  is a diagram illustrating a state where the robot is operated on a machining area B side in the configuration illustrated in  FIG. 2 , 
           [0027]      FIG. 4A  is a diagram illustrating a cover structure of the robot when viewed from a top in a state where an area in the configuration illustrated in  FIGS. 3A and 3B  is partitioned into two areas; 
           [0028]      FIG. 4B  is a diagram illustrating a cover structure of the robot when viewed from a top in a state where the area in the configuration illustrated in  FIGS. 3A and 3B  is partitioned into four areas; 
           [0029]      FIG. 5A  is a diagram illustrating an embodiment in which the robot is protected by two covers, and is a diagram illustrating a state where the covers are closed; 
           [0030]      FIG. 5B  is a diagram illustrating the embodiment in which the robot is protected by the two covers, and is a diagram illustrating a state where the covers are opened, and an end effector comes outside the covers; 
           [0031]      FIG. 5C  is a diagram illustrating the embodiment in which the robot is protected by the two covers, and is a diagram illustrating a state where a rotating axis J 1  is rotated to change a posture; 
           [0032]      FIG. 5D  is a sectional view of  FIG. 5A ; and 
           [0033]      FIG. 5E  is a sectional view of  FIG. 5B . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    Hereinafter, embodiments of the invention will be described with reference to the drawings. 
         [0035]      FIG. 2  illustrates an embodiment of the invention. A robot  1  is a vertical articulated robot having six axes (J 1  to J 6 ), and has a configuration in which a cover  20  is fixed to a rotating axis (J 1 ) in the base portion of the robot, and the cover  20  is concomitantly rotated (see an arrow  22 ) when the rotating axis J 1  is rotated. 
         [0036]    A cover opening portion  21  is provided in the cover  20 , and an end effector  2  can be taken outside the cover  20  through the cover opening portion  21 . The robot  1  can be protected from a chip or a cutting liquid scattered from a back surface since the back surface of the robot  1  is constantly covered with the cover  20  in this structure. The cover  20  has a rotationally symmetric shape with respect to the central axis of the rotating axis J 1  except for the cover opening portion  21 . 
         [0037]    The cover opening portion  21  is minimized to such a degree as not to largely limit the operation range of the robot so that the cover  20  protects the robot  1  even when the rotating axis J 1  is rotated in a certain degree. The cover  20  is fixed to the rotating axis J 1  in the case of this structure, and thus the collision between the cover  20  and the robot  1  cannot occur however quickly the rotating axis J 1  is rotated. Further, the relative position between the rotating axes J 2  to J 6  and the cover  20  is constantly maintained, and thus the collision with the cover  20  does not occur in principle when the operation range of the rotating axes J 2  to J 6  with respect to the cover  20  is determined. 
         [0038]      FIGS. 3A and 3B  are diagrams illustrating an embodiment in which the structure of  FIG. 2  is further provided with a fixed wall.  FIG. 3A  illustrates a state where the robot  1  is operated on an operation area A side, and  FIG. 3B  illustrates a state where the robot  1  is operated on a machining area B side. 
         [0039]    The cover  20  has a substantial cylindrical shape (rotationally symmetric shape), the central axis of the cylinder substantially matches the rotational center of the axis J 1 , a fixed wall  23  is disposed outside the rotation trajectory of the cover  20 , and the cover  20  is disposed inside a fixed wall opening portion  26  of the fixed wall  23 . That is, the cover  20  is disposed to block the fixed wall opening portion  26 . This structure makes the rotation trajectory, which is drawn by the cover  20  while the rotating axis J 1  rotates, be substantially constant, the fixed wall  23  is present outside the cover with a slight gap interposed therebetween, and thus the operation area A and the machining area B can be separated with a sufficiently small gap. That is, the intrusion of the chip or the cutting liquid from the machining area B of a machine tool  7  to the operation area A of the robot  1  can be minimized. Therefore, the structure of  FIG. 3  has a function as a cover to protect the robot  1  completely similarly to the conventional opening/closing door (door  4 ) of  FIG. 1 . 
         [0040]    The conventional structure of  FIGS. 1A and 1B  requires an actuator which opens and closes a door  4  or a sensor which detects whether the door is opened or closed. Meanwhile, in the structure of  FIGS. 3A and 3B , the area where the cover opening portion  21  of the cover  20  faces between the operation area A and the machining area B is determined by the angle of the rotating axis J 1 , and thus the area where the cover opening portion  21  presently faces is constantly apparently known from the angle of the rotating axis J 1 . Therefore, the cover  20  can perform a function to open and close the door  4  without an additional actuator and sensor. 
         [0041]    The robot  1  takes a posture in which the end effector  2  is present inside the cover  20  when the rotating axis J 1  is rotated to switch the operation area (operation area A and machining area B) of the robot  1 , and thus it is prevented that the collision with the fixed wall  23  occurs. Therefore, whether the collision occurs can be found out from only the posture of the robot  1 , and thus the collision with the fixed wall  23  can be also avoided without using an additional sensor when the operation range is set by a control device (not illustrated) of the robot  1 . 
         [0042]      FIG. 4  illustrates an embodiment of the invention having configuration of partitioning an area.  FIG. 4A  is a schematic diagram when viewed from the top of  FIG. 3 , and in the structure of  FIG. 4 , the fixed wall  23  on the machining area B side is closed since the machining area B is generally closed by a mechanic cover. In the structure of this case, the fixed wall  23  partitions the area into two areas, that is, the machining area B and the operation area A.  FIG. 4B  illustrates a structure in which the operation area A is further partitioned so that the fixed wall  23  partitions the area into four areas, that is, the operation area A, an operation area C, an operation area D, and the machining area B. For example, the operation area A is an area which a workpiece  13  comes out and in, the operation area C is an area where the workpiece  13  is cleaned, and the operation area D is an area where a hand of the robot  1  is exchanged. That is, the areas can be partitioned depending on each purpose of the operation. 
         [0043]    The direction of the cover opening portion  21  of the cover  20  is changed according to the rotation angle of the rotating axis J 1  to determine the area where the robot  1  operates. The cover opening portion  21  of the cover  20  is desirably minimized to such a degree as not to interrupt the operation of the robot  1  in order that the areas are strictly separated by the cover  20 . 
         [0044]    For example, in a case where a cleaning liquid is used in high volume in the operation area C of  FIG. 4B , there is a concern that the cleaning liquid leaks into the operation area A or the machining area B, and thus it is necessary to store the cover opening portion  21  of the cover  20  in the operation area C during cleaning. On the other hand, a hand exchange in the operation area D is performed with no problem even when the cover opening portion  21  of the cover  20  is positioned between the operation area A and the operation area D since the hand exchange does not cause any scatter. Herein, a person can approach the operation area A open to the outside with no safety problem as long as the end effector  2  of the robot is present in the operation area D, and thus a surface  23   a  of the fixed wall between the operation area D and the operation area A is meaningful. 
         [0045]    In a case where the areas are partitioned by the rotationally symmetric cover  20 , the gap between the fixed wall  23  and the cover  20  can be minimized when the fixed wall  23  extends radially from the rotational center of the cover  20  (the rotational center of the rotating axis J 1 ), which is advantageous in terms of improving the sealability of each area. Further, the wall extending radially secures, particularly, the large rotation range of the rotating axis J 1  in each area, which is a merit in terms of securing the large operation range of the robot  1  in each area. 
         [0046]      FIGS. 5A to 5E  illustrate an embodiment of the invention using two covers. The embodiment illustrated in  FIGS. 3A and 3B  or  FIGS. 4A and 4B  has a structure in which the robot  1  is protected from the scattered chip or the cutting liquid by combining the fixed wall  23  and one cover  20 , but the structure of  FIGS. 5A to 5E  is a structure in which the robot is protected by two covers  20  and  25  attached to the robot  1 . Incidentally, a cover  24  covers the lower portion of the robot, and is fixed to a floor or the base portion of the robot. 
         [0047]      FIG. 5A  illustrates a state where the cover is closed,  FIG. 53  illustrates a state where the cover is opened, and the end effector comes outside the cover, and  FIG. 5C  illustrates a state where the rotating axis J 1  is rotated to change the posture. In addition,  FIGS. 5D and 5E  are respective sectional views of  FIGS. 5A and 53 , the cover  20  is fixed to the rotating axis J 1  (first movable portion), and a cover  25  is fixed to an arm J 3  (second movable portion). A wrist swinging axis J 5  is provided in the tip of the arm J 3 . A wrist rotating axis J 6  which rotates a wrist is provided in the wrist swinging axis J 5 . The end effector  2  is mounted in the wrist rotating axis J 6 . The end effector  2  is a device which grips the workpiece  13  and the like. 
         [0048]    In this structure, the cover  25  has a shape of blocking the opening portion  21  of the cover  20 , and the joint surface of the cover  20  is joined to the joint surface of the cover  25  without a gap so that the cover of the robot  1  becomes in a closed state when the robot  1  takes a posture of  FIGS. 5A and 5D . Since the cover is closed, the chip or the cutting liquid is not splashed on the robot  1  even when the robot  1  is disposed in the machining area B. The two covers  20  and  25  are used for the sealing in FIGS.  5 A to  5 E, but three of more covers may be used for the sealing in combination. 
         [0049]    Unlike the structure of  FIGS. 3A and 3B  or  FIGS. 4A and 4B , the robot  1  in the structure of  FIGS. 5A to 5E  cannot be operated in a state where the covers  20  and  25  are closed since the posture of the robot  1  is determined. However, the cover of the robot  1  can be compactly formed so that the robot  1  can be disposed in a narrow space in the machining area B, and further, the distance between the workpiece  13  and the robot  1  becomes smaller, and thus there is a merit that the workpiece  13  can be automatically exchanged by a smaller size of robot  1 . 
         [0050]    According to the invention, a cover structure of the robot can be provided in which the robot can be protected from a generation source of a contamination material to contaminate the robot by fixing the cover to the movable portion of the robot. More specifically, the cover is opened and closed by a motion of each axis of the robot since the cover is attached to the movable portion of the robot. Therefore, it is not necessary to additionally prepare the actuator to open and close the cover. In addition, the cover is attached to the robot itself unlike the case of opening and closing the door. Therefore, when the operation range of the robot is set in advance, it is prevented that an erroneous operation causes the robot to collide with the cover, and the collision does not occur however quickly the operation is performed.