Abstract:
A machining tool with a numerical control device includes an actual gravity center calculation unit configured to calculate an actual gravity center, the actual gravity center being a whole gravity center of the machining tool and the load, a target gravity center position set unit, a movable part position correction unit configured to correct the relative position of the movable part to the fixed part, to make the target gravity center position and the whole center gravity center position of the machining tool and the load coincident.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a machining tool with a numerical control device, and particularly relates to a machining tool with a numerical control device having adjustment function of gravity center of a main body of the machining tool. 
         [0003]    2. Description of the Related Art 
         [0004]    A relatively small and lightweight machining tool is often moved a short distance. Moving method includes, hoisting the machining tool with a crane or the like, and lifting the machining tool by a dolly or a lift such as a forklift or a manual forklift. Since a lift itself is compact, the lift is used for relatively short distance relocation, such as relocation in a factory building. 
         [0005]    When a lift raises a machining tool, fork position and fork width need to be determined such that a gravity center of the machining tool is located between the two forks of the lift. It is important to grasp the gravity center position of the machining tool to determine the fork position and the fork width. 
         [0006]    Japanese Patent Laid-Open No. 2005-131715 discloses a technique in which a transport auxiliary device for an industrial robot uses a forklift. In the industrial robot, engaging holes are formed and exclusive parts are attached to a base portion, such that a gravity center of the whole robot comes between the two forks of the forklift. The forklift inserts the forks to a receiving portion to lift the robot in a stable conveying attitude. 
         [0007]    A small machining tool may also be relocated by a lift. For many small machining tools, lift insertion points are not fixed. When a moving part position and a weight of a load mounted on the moving part such as a top face of a table change in every replacement, the gravity center position also changes, so the lift insertion points need to be decided according to the gravity center position. 
         [0008]    There are two methods of relocation of a small machining tool by a lift. One method is to raise the machining tool after the lift is positioned according to the gravity center position of the machining tool. The other method is to position the moving part such that the gravity center position comes between the forks after the position of the lift is determined preliminarily. 
         [0009]    In the latter method of positioning the moving part after the position of the lift is determined preliminarily, a position of the moving part for stable lifting is determined in the end, after such operations are repeatedly tried that, moving part position where a gravity center position comes between the forks is predicted and assumed first, then the machining tool is lifted, and a moving part position is corrected according to the balance of the lifted machining tool. When the first assumed gravity center position is markedly different from the true gravity center position, trial times increases causing man-hours increase. In addition, there is a possibility that repetition of lifting up and lifting down causes a load on machine parts. Therefore, it is desirable to grasp precisely from the first, a movable part position where the gravity center comes between the forks, so as to reduce number of trials. 
         [0010]    In addition to that, lifting operation by a forklift is performed while an electrical source of a machine is deactivated in many cases. In these cases, such a way is adopted that, a movable part position is moved directly by hand forcibly to correct a movable part position, since positioning by a numerical control device is impossible. This way can not be adopted for a machine with a configuration in that the brake is applied to a moving shaft while an electrical power is deactivated. 
         [0011]    Considering these things above mentioned, such a machine is desirable that, a moving part is precisely positioned while an electrical power of the machine is activated, for correction of the position of the moving part. 
       SUMMARY OF THE INVENTION 
       [0012]    Therefore, the object of the invention is to provide a machining tool with a numerical control device, capable of adjusting a gravity center position of the machining tool to an arbitrary point in a simple way. 
         [0013]    A machining tool with a numerical control device according to the invention includes a numerical control device, a machining tool to be controlled by the numerical control device, the machining tool having a fixed part, and a movable part on which a load is configured to be loaded. The numerical control device includes a storage unit configured to store weight and gravity center position of each the fixed part, movable part, and the load, an actual gravity center calculation unit configured to calculate an actual gravity center, the actual gravity center being a whole gravity center of the machining tool and the load, based on the gravity center position and the weight of the fixed part stored in the storage unit, the gravity center position and the weight of the movable part stored in the storage unit, a relative position of the movable part to the fixed part, and the gravity center position and the weight of the load stored in the storage unit, a target gravity center position set unit configured to set a target gravity center position, the target gravity center position being the whole gravity center position of the machining tool and the load, a movable part position correction unit configured to correct the relative position of the movable part to the fixed part, to make the target gravity center position set by the target gravity center position set unit and the whole center gravity center position of the machining tool and the load coincident. 
         [0014]    The machining tool includes a target gravity center position set unit configured to set a target gravity center position for the whole gravity center position of the machining tool and the load, and a movable part position correction unit configured to correct the relative position of the movable part to the fixed part, to make the target gravity center position and the whole center gravity center position coincident. Therefore, the machining tool is capable of adjust the gravity center position of the machining tool to an arbitrary point. 
         [0015]    A machining tool with a numerical control device according to the present invention includes a movable part position correction unit configured to correct a relative position of the movable part to a fixed part, to make the target gravity center position and the whole center gravity center position coincident, after the target gravity center position, which is whole gravity center position of the machining tool and the load, is set. With the movable part position correction unit, the machining tool is able to adjust gravity center position of the machining tool to arbitrary position, and even when lift position is arbitrary set for relocation by a forklift or the like, subsequent gravity center point change by movable part position adjustment enables operation with a stable attitude. 
         [0016]    By configuring the present invention as described above, a machining tool with a numerical control device, capable of adjusting a gravity center position of the machining tool to an arbitrary point in a simple way, can be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The above-described object, the other object, and the feature of the invention will be proved from the description of embodiments below with reference to the accompanying drawings. In these drawings: 
           [0018]      FIG. 1  is a schematic view of a machining tool with a numerical control device according to an embodiment of the present invention. 
           [0019]      FIG. 2  is a block diagram illustrating calculation method of whole gravity center position of a machining tool and a load according to an embodiment of the present invention. 
           [0020]      FIG. 3  is a view showing movement of a movable part in a machining tool with a numerical control device according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]      FIG. 1  shows a schematic view of a machining tool with a numerical control device in an embodiment of the present invention. Numeral “ 1 ” denotes a numerical control device, including CPU  7  and a storage  8  inside thereof, and a display unit  9  and an input unit  10  on its surface. The numerical control device is connected to a machining tool  11 . The machining tool  11  comprises, a base  2 , a column  3 , a spindle head  4 , a table  5 , etc. Numeral “ 6 ” denotes a load such as a workpiece on a top face of the table or a jig. The base  2  and the column  3 , which remain stationary with respect to a ground plane, correspond to a fixed part. The spindle head  4  and the table  5 , which are relatively movable to a fixed part including the base  2  and the column  3  with a control command issued by a numerical control device  1 , correspond to a movable part. 
         [0022]    In advance, gravity center position and weight of the fixed part, and a gravity center position and a weight of the movable part, are stored in the storage  8  installed in the numerical control device  1 . The fixed part includes the base  2 , the column  3 , and the like, while the movable part includes the spindle head  4 , the table  5 , and the like. CPU  7  calculates whole gravity center position of the machining tool  11  and the load  6 , based on relative position of the movable part including the spindle head  4 , the table  5 , and the like, to the fixed part, and based on information concerning the gravity center position and the weight of the load  6  mounted on the table  5  acquired by a predetermined method. Specific method of the calculation will be described later. 
         [0023]    The display unit  9  displays whole gravity center position of the machining tool  11  and the load  6 , calculated by CPU  7 . Information on a component of at least one direction may be displayed when the gravity center position is displayed. 
         [0024]    Information on the gravity center position is input by an operator using an input unit  10 . Relation of, the weight and the gravity center position of the load  6  to be mounted on the table  5  and parameters in acceleration and deceleration of the table  5 , may be set in the storage  8  in the numerical control device  1 . In this case, the gravity center position and the weight of the load  6  mounted on the table  5  may be estimated to use them, from values of parameters in acceleration or deceleration, by moving the table  5  on which the load  6  is mounted. The input unit may also be used to specify a target gravity center position as described later. 
         [0025]      FIG. 2  is a block diagram illustrating calculation method of the whole gravity center position of the machining tool  11  and the load according  6 , using information on the gravity center position and the weight of the load  6 . Hereinafter, each step will be explained. 
         [0026]    First of all, components of the machining tool  11  are distinguished between a fixed part and a movable part. The fixed part remains stationary with respect to a ground plane, while the movable part is relatively movable to the fixed part. In the present embodiment, the fixed part includes the bed  2  and the column  3 , and the movable part includes the spindle head  4  and the table  5 . First, in block B 1 , values of the gravity center position and the weight of the movable part, and values of the gravity center position and the weight of the fixed part, are obtained. In block B 2 , position information of the movable part is obtained. In block B 3 , the weight of the load  6  is obtained. The weight of the load  6  may be obtained in such a way that, an operator input the weight by the input unit  10 , or the weight is estimated from a value of parameters in acceleration or deceleration by moving the table  5  on which the load  6  is mounted. 
         [0027]    In block B 4 , the whole gravity center position of the machining tool  11  and the load  6  is calculated by CPU  7 , based on the position information of the movable part, the gravity center position and the weight of the movable part, the gravity center position and the weight of the fixed part, the weight of the load. Then the calculated whole gravity center position values are stored in the storage  8  in block B 5 . At this time, the calculated whole gravity center position values may be displayed by the display unit  9 . 
         [0028]    In block B 6 , the target gravity center position is specified using the input unit  10 . The specified target gravity center position is stored in the storage  8  in block B 7 . At this time, the specified target gravity center position values may be displayed by the display unit  9 . 
         [0029]    In block B 8 , movable part correction amount is calculated based on the current gravity center position and the target gravity center position stored in the storage  8 . Movable part position correction command is issued based on the calculated movable part correction amount, and the movable part position is corrected, in block B 9 . Specific methods of the calculation of the gravity center position and the movable position correction amount will be described later. 
         [0030]    Next, specified calculation method of the gravity center will be explained. 
         [0031]    Whole gravity center position of the machining tool  11  and the load  6  is calculated using the following equation. 
         [0000]    
       
         
           
             
               
                 
                   
                     r 
                     → 
                   
                   = 
                   
                     
                       
                         
                           M 
                           S 
                         
                          
                         
                           
                             r 
                             → 
                           
                           S 
                         
                       
                       + 
                       
                         
                           M 
                           H 
                         
                          
                         
                           
                             r 
                             → 
                           
                           H 
                         
                       
                       + 
                       
                         
                           M 
                           T 
                         
                          
                         
                           
                             r 
                             → 
                           
                           T 
                         
                       
                       + 
                       
                         
                           M 
                           L 
                         
                          
                         
                           
                             r 
                             → 
                           
                           L 
                         
                       
                     
                     M 
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
             
               
                 
                   M 
                   = 
                   
                     
                       M 
                       S 
                     
                     + 
                     
                       M 
                       H 
                     
                     + 
                     
                       M 
                       T 
                     
                     + 
                     
                       M 
                       L 
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
       
         {right arrow over (r)}: Whole gravity center position vector of the machining tool and the load 
         {right arrow over (r)} S : Gravity center position vector of the fixed part, including the base and the column 
         {right arrow over (r)} H : Gravity center position vector of the spindle head 
         {right arrow over (r)} T : Gravity center position vector of the table 
         {right arrow over (r)} L : Gravity center position vector of the load mounted on the table 
         M: Total mass of the fixed part and the movable part 
         M S :Total mass of the fixed part, including the base and the column 
         M H : Mass of the spindle head 
         M T : Mass of the table 
         M L : Mass of the load mounted on the table 
       
     
         [0042]    Here, components which has no need to be considered for calculation of the gravity center position, can be neglected in the calculation process. 
         [0043]    As an example, a reference coordinate system  90  is used, in which horizontal direction and vertical direction are set as a basis, and the horizontal direction coincides with a direction of the side face (y direction) at the time when the machining tool is set, and the vertical direction coincides with z direction, as shown in  FIG. 3 . In addition, a reference position mark  91  as a reference of position is provided on the fixed part, and the origin of coordinates of the reference coordinate system  90  is made coincide with the reference position mark  91 . 
         [0044]    Thus, information on the gravity center position is expressed as a vector amount expressed in equation (1), with the reference position mark  91  as the origin of the coordinates. 
         [0045]    An example is considered, where a lift is inserted in x direction to the reference coordinate  90 , in the following. 
         [0046]    Here, only y direction component needs to be considered for considering the gravity center position, so only y direction component is considered in equation (1). The component is calculated by the following equation. 
         [0000]    
       
         
           
             
               
                 
                   
                     r 
                     y 
                   
                   = 
                   
                     
                       
                         
                           M 
                           S 
                         
                          
                         
                           r 
                           Sy 
                         
                       
                       + 
                       
                         
                           M 
                           H 
                         
                          
                         
                           r 
                           Hy 
                         
                       
                       + 
                       
                         
                           M 
                           T 
                         
                          
                         
                           r 
                           Ty 
                         
                       
                       + 
                       
                         
                           M 
                           L 
                         
                          
                         
                           r 
                           Ly 
                         
                       
                     
                     M 
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
         [0047]    In a case where y direction component of the gravity center position of the table  5  coincides approximately with y direction component of the gravity center position of the load  6 , the equation (3) is approximated as the following equation, omitting information on the gravity center position of the load  6 . 
         [0000]    
       
         
           
             
               
                 
                   
                     r 
                     y 
                   
                   = 
                   
                     
                       
                         
                           M 
                           S 
                         
                          
                         
                           r 
                           Sy 
                         
                       
                       + 
                       
                         
                           M 
                           H 
                         
                          
                         
                           r 
                           Hy 
                         
                       
                       + 
                       
                         
                           ( 
                           
                             
                               M 
                               T 
                             
                             + 
                             
                               M 
                               L 
                             
                           
                           ) 
                         
                          
                         
                           r 
                           Ty 
                         
                       
                     
                     M 
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
         [0048]    Specified calculation method of the movable part position correction will follow. 
         [0049]    When arbitrary gravity center position as a target is given by the input unit  10 , the following equation is obtained from the equation (1). 
         [0000]    
       
         
           
             
               
                 
                   
                     γ 
                     → 
                   
                   = 
                   
                     
                       
                         
                           M 
                           S 
                         
                          
                         
                           
                             r 
                             → 
                           
                           S 
                         
                       
                       + 
                       
                         
                           M 
                           H 
                         
                          
                         
                           
                             γ 
                             → 
                           
                           H 
                         
                       
                       + 
                       
                         
                           M 
                           T 
                         
                          
                         
                           
                             γ 
                             → 
                           
                           T 
                         
                       
                       + 
                       
                         
                           M 
                           L 
                         
                          
                         
                           
                             γ 
                             → 
                           
                           L 
                         
                       
                     
                     M 
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
       
         {right arrow over (γ)}: position vector of target gravity center position of the whole of the fixed part and the movable part 
         {right arrow over (γ)} H : gravity center position vector of the spindle head in a case of {right arrow over (r)}={right arrow over (γ)} 
         {right arrow over (γ)} T : gravity center position vector of the table in a case of {right arrow over (r)}={right arrow over (γ)} 
         {right arrow over (γ)} L : gravity center position vector of the load mounted on the table in a case of {right arrow over (r)}={right arrow over (γ)} 
       
     
         [0054]    Considering the y direction component of the equation (5), since the spindle head  4  can move only in z direction in the machining tool with a configuration shown in  FIG. 1 , γ Hy  is equal to r Hy . When γ Ty  is regarded to be equal to r Ly , the following equation is obtained from the equation (4). 
         [0000]    
       
         
           
             
               
                 
                   
                     γ 
                     y 
                   
                   = 
                   
                     
                       
                         
                           M 
                           S 
                         
                          
                         
                           r 
                           Sy 
                         
                       
                       + 
                       
                         
                           M 
                           H 
                         
                          
                         
                           r 
                           Hy 
                         
                       
                       + 
                       
                         
                           ( 
                           
                             
                               M 
                               T 
                             
                             + 
                             
                               M 
                               L 
                             
                           
                           ) 
                         
                          
                         
                           γ 
                           Ty 
                         
                       
                     
                     M 
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
         [0000]    The following equation is obtained from the equations (4) and (6). 
         [0000]    
       
         
           
             
               
                 
                   
                     γ 
                     Ty 
                   
                   = 
                   
                     
                       r 
                       Ty 
                     
                     + 
                     
                       
                         M 
                         
                           
                             M 
                             T 
                           
                           + 
                           
                             M 
                             L 
                           
                         
                       
                        
                       
                         ( 
                         
                           
                             γ 
                             y 
                           
                           - 
                           
                             r 
                             y 
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
           
         
       
     
         [0055]    Gravity center position of the whole machine coincides with the target position γ y , when y direction component of the table is made to be γ Ty  calculated from equation (7). 
         [0056]    The details will be explained using  FIG. 3 . The position of the table and the load  6  is shown with solid line, and numeral “ 23 ” denotes the current position of the movable part. Numeral “ 21 ” denotes the gravity center position of the whole machining tool of the fixed part and the movable part, and numeral “ 22 ” denotes y direction component of gravity center position  21  of the whole machining tool. 
         [0057]    When a target gravity center position  31  as the target position is specified by the input unit  10  or the like, the movable part position correction unit calculates a position of the movable part  33  where the gravity center position of the whole machining tool coincides with the target gravity center position  31 , and the movable part is moved so that the movable part position coincides with the above mentioned position of the movable part  33 . Here, numeral “ 32 ” denotes y direction component of the target gravity center position  31 . 
         [0058]    In general, movable range of the movable part of the machine is restricted physically or by a software program, hence such a configuration may be adopted that warning is given by alarming or the like in a case where the value obtained in the equation (7) exceeds the range.