Abstract:
An extrusion press die-slide device is equipped with: a fixed frame; a moveable frame that can move linearly but which is supported by the fixed frame in a non-rotatable manner; a first motion conversion mechanism that converts input rotational motion to linear motion and outputs the same to cause the moveable frame to move linearly with respect to the fixed frame; and a second motion conversion mechanism attached to the moveable frame and equipped with a pusher to impart a pressing force to a die of the extrusion press, and which transmits the input rotational motion to the first motion conversion mechanism and converts the input rotational motion to linear motion and outputs the same to cause the pusher to move linearly with respect to the moveable frame.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a die-slide device of an extrusion press for extruding a billet of a ferrous metal or nonferrous metal from a die to form a shaped member. 
       BACKGROUND ART 
       [0002]    In general, when extruding a billet made of a metal material such as aluminum or an alloy material thereof by an extrusion press machine, an extrusion stem is attached to a front end part of a main ram driven by a hydraulic cylinder. A container is pressed against a die. 
         [0003]    In that state, the billet is stored in the container by the extrusion stem or the like. Further, the main ram is made to further advance by being driven by the hydraulic cylinder whereby the billet is pressed by the extrusion stem. Therefore, a shaped product is pushed out from an outlet part of the die. 
         [0004]    Even in the past, there are many types of extruded products and the frequency of changing dies had increased. In recent years, however, the production of extremely small lots of diverse products has been increasing. Along with this, the frequency of changing dies has also dramatically increased. As opposed to this, in the conventional die changing device, although the die changing time has been shortened, there has been a demand for further reduction of time. Further, the conventional die changing device uses a hydraulic cylinder, so the hydraulic cylinder is long and a large space is required. Furthermore, according to PLT 1, a die is changed by driving a chain installed on the container side of the end platen to thereby make the die move from an extrusion position to a changing position outside the extrusion press and changing the dies, then again move the die to the extrusion position. The chain is installed in the vicinity of the heated die and container, so the chain became high in temperature and maintenance of the chain took more time compared with a usual one used cold. 
       CITED REFERENCE LIST 
     Patent Literature 
       [0005]    PLT 1: Japanese Patent Publication No. 2013-244509A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    A conventional die changing device uses a hydraulic cylinder, so the hydraulic cylinder is long and a large space is required. Further, there is also a risk of fire due to leakage of oil after long years of use. 
         [0007]    In a conventional type, a die may be changed by driving a chain installed on the container side of the end platen to thereby make the die move from an extrusion position to a changing position outside the extrusion press and changing the dies, then again move the die to the extrusion position. The chain is installed in the vicinity of the heated die and container, so the chain became high in temperature and maintenance of the chain took more time compared with a usual one used cold. 
       Solution to Problem 
       [0008]    In order to solve the aforementioned problems, according to a first aspect of the present invention, there is provided a die-slide device of an extrusion press, comprising a fixed frame, a moving frame supported by the fixed frame to be able to linearly move with respect to the fixed frame but to be unable to rotate, a first motion converting mechanism for converting input rotational motion to linear motion and outputting the same so as to move the moving frame linearly with respect to the fixed frame, and a second motion converting mechanism having a pusher for pushing against a die of the extrusion press and attached to the moving frame, the second motion converting mechanism transmitting input rotational motion to the first motion converting mechanism and moving the pusher linearly with respect to the moving frame by converting the input rotational motion to linear motion and outputting the same. 
         [0009]    In the present invention, the first motion converting mechanism may be provided with a first ball screw fixed to the fixed frame and extending in a direction of movement of the moving frame, a first nut screwed to the first ball screw and rotatably supported by the moving frame, and a first gear fixed to the first nut, the second motion converting mechanism may be provided with a second ball screw rotatably supported by the moving frame, a second nut screwed to the second ball screw and fixed to the pusher, and a second gear fixed to the second ball screw and meshing with the first gear of the first motion converting mechanism, and the pusher may be supported by the moving frame to be able to linearly move with respect to the moving frame, but to be unable to rotate. 
         [0010]    In the present invention, the die-slide device may further comprise a motor supplying rotational drive power to the second motion converting mechanism and the motor may be fixed to the moving frame and move together with the moving frame. 
         [0011]    In the present invention, the moving frame may be supported by the fixed frame via a linear guide device. 
         [0012]    According to a second aspect of the present invention, there is provided an extrusion press comprising the die-slide device and a cutting device for cutting an extruded product extending through a die and an end platen of the extrusion press when changing a die of the extrusion press, in which extrusion press, the cutting device is attached to the end platen of the extrusion press, and the cutting device comprises a pusher of cutting device which moves in the same direction as the direction of movement of the pusher of the die-slide device to push against the die. 
         [0013]    In the present invention, the cutting device may comprise a hydraulic cylinder for driving the pusher of cutting device. 
         [0014]    In the present invention, the cutting device may comprise a ball screw, a nut screwed to the ball screw, and a motor for supplying rotational power to the ball screw to drive the pusher of cutting device. 
         [0015]    In the present invention, the cutting device may have a stroke of cutting the extruded product of about 0.8 time a diameter of the die. 
         [0016]    In the present invention, a non-combustible hydraulic fluid may be used as hydraulic fluid of the hydraulic cylinder of the cutting device. 
       Advantageous Effects of the Invention 
       [0017]    In the present invention, since the second motion converting mechanism is attached to the moving frame that is linearly moved by the first motion converting mechanism, the stroke of the pusher is obtained as the stroke of the total of the amounts of movement generated by the first motion converting mechanism and the second motion converting mechanism. As a result, the overall length of the die-slide device can be shortened as compared with the conventional one, therefore the installation area can be minimized and space saving of the equipment can be realized. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]      FIG. 1  is a longitudinal cross-sectional view of a principal part of an extrusion press according to a first embodiment of the present invention. 
           [0019]      FIG. 2  is a longitudinal cross-sectional view of a die-slide device of an extrusion press according to a first embodiment of the present invention. 
           [0020]      FIG. 3  is a view of a state in which the die-slide device shown in  FIG. 2  is coupled with a die as seen from a container side. 
           [0021]      FIG. 4  is a view of the state, seen from the container side, of the time when the die-slide device shown in  FIG. 2  moves the die out of the extrusion press or the time of the longest stroke of the device. 
           [0022]      FIG. 5  is a plan view of the die-slide device of an extrusion press according to the first embodiment of the present invention. 
           [0023]      FIG. 6  is a plan view of the die-slide device and a cutting device of the extrusion press according to the first embodiment. 
           [0024]      FIG. 7  is a plan view of a die-slide device and a cutting apparatus of an extrusion press according to a second embodiment of the present invention. 
           [0025]      FIG. 8  is a schematic view showing two sprockets of a die-slide device of an extrusion press according to a modification of the first embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    Embodiments of a die-slide device of an extrusion press according to the present invention will be described in detail below with reference to the drawings. 
         [0027]    First, an outline of an extrusion press according to a first embodiment of the present invention will be described with reference to  FIG. 1 . The extrusion press shown in  FIG. 1  is of the single acting short stroke type, in which an end platen  1  and a main cylinder  2  are arranged to face each other and the two are connected by a plurality of tie rods  3 . A die  4  formed with an extrusion hole is disposed between the inner surface of the end platen  1  and a container  5 . A billet  6  is loaded in the container  5 . This is pushed and pressed toward the die  4 , whereby an extruded material of a cross-section corresponding to the die hole is extruded. 
         [0028]    The main cylinder  2  that generates an extrusion acting force has a main ram  9  built therein and is capable of pressing and moving it toward the container  5 . At the front end part of the main ram  9 , an extrusion stem  7  is attached through a main cross head  8  in a state projecting toward the container  5  to be arranged coaxially with a billet loading hole of the container  5  by making it closely contact a not shown dummy block at its tip. When the main cylinder  2  is driven to advance the main cross head  8 , the extrusion stem  7  is inserted into the billet loading hole of the container  5  and presses the rear end face of the loaded billet  6  to push out the extruded material. 
         [0029]    Note that a plurality of side cylinders  10  are attached to the main cylinder  2  in parallel with the axial center of extrusion. Cylinder rods  11  of the side cylinders are connected to the main cross head  8 . Due to this, the extrusion stem  7  can be initially moved to a position close to the container  5  as a preparation step of the extrusion process. The extrusion pressurizing operation is performed using both the main cylinder  2  and the side cylinders  10 . 
         [0030]      FIG. 2  is a longitudinal cross-sectional view of a die-slide device  21  of the extrusion press according to the first embodiment of the present invention. The die-slide device  21  includes a fixed frame  42 , a moving frame  26 , a linear guide device  27 , a first motion converting mechanism, a second motion converting mechanism, and a motor  25  fixed to the moving frame  26 . 
         [0031]    The first motion converting mechanism includes a first gear  23 , a first nut  31 , a first ball screw  32 , and a first bearing  35 . The second motion converting mechanism includes a second gear  22 , a second nut  33 , a second ball screw  34 , a second bearing  36 , a pusher  37 , and a pulley  24 . The first ball screw  32  and the second ball screw  34  are arranged in parallel. 
         [0032]    When the motor  25  rotates the pulley  24  through a timing belt  29  or a chain, the second gear  22  and the first gear  23  meshing therewith rotate. The first gear  23  and the second gear  22  rotate in opposite directions. In the figure, a case where the first gear  23  rotates clockwise and the second gear  22  rotates counterclockwise when viewed from the arrow A will be explained. 
         [0033]    In the first motion converting mechanism, the first nut  31  and the first gear  23  are fastened together. The first ball screw  32  is fixed to the fixed frame  42 . The first nut  31  is screwed with the first ball screw  32  and is rotatably supported by the moving frame  26  via the first bearing  35 . Therefore, the first nut  31  is constrained in linear movement with respect to the moving frame  26 , but can freely rotate. Therefore, when the first gear  23  is rotated and the first nut  31  rotates, the first nut  31  moves on the first ball screw  32  in the left direction in the drawing. Accordingly, the moving frame  26  also moves to the same direction as the first nut  31 . Further, the moving frame  26  is supported by the fixed frame  42  via the linear guide device  27  so as to be able to move linearly with respect to the fixed frame  42 , but not to be able to rotate. The motor  25  is fixed to the moving frame  26 , so the motor  25  also moves simultaneously in the left direction in the drawing. 
         [0034]    A front end part  38  on the left side of the moving frame  26  in the drawing has a rectangular parallelepiped block. Further, an inner sliding member  39  and outer sliding member  40  are attached thereto. The inner sliding member  39  is disposed between the front end part  38  of the moving frame  26  and the pusher  37  inserted through the center portion thereof. The outer sliding member  40  is disposed between the lower surface of the front end part  38  of the moving frame  26  and a guide  18  provided on the container side surface of the end platen  1  of the extrusion press. As a result, the front end part  38  of the moving frame  26  extending from the fixed frame  42  in the left direction in the drawing is guided by the guide  18  and therefore is supported to be able to linearly move with respect to the guide  18 , but to be unable to rotate. 
         [0035]    On the other hand, in the second motion converting mechanism, the second ball screw  34  fixed to the second gear  22  is supported by the moving frame  26  to be able to rotate through the second bearing  36 . In the present embodiment, the second ball screw  34  rotates in the opposite direction to the first gear  23 . The second nut  33  screwed to the second ball screw  34  is fixed to a cylindrical pusher  37  extending long in the left direction in the drawing. The cylindrical front end part of the pusher  37  is supported by the front end part  38  of the moving frame  26  so as to be able to linearly move with respect to the moving frame  26  via the inner sliding member  39  but not to be able to rotate. Therefore, the second nut  33  fixed to the pusher  37  is also able to linearly move with respect to the moving frame  26 , but not to be able to rotate. Therefore, when the second ball screw  34  rotates in the reverse direction to the first gear  23 , the second nut  33  moves to the left in the drawing. 
         [0036]    Since the die-slide device  21  is configured as described above, the stroke of the pusher  37  is equal to the total of the amount of linear movement of the moving frame  26  with respect to the fixed frame  42  based on the operation of the first motion converting mechanism and the amount of linear movement of the pusher  37  with respect to the moving frame  26  based on the operation of the second motion converting mechanism. 
         [0037]    In the drawing, when the ball screw is a right-handed screw, the first nut  31  rotates to the right in the first motion converting mechanism, so the first nut  31  moves in the left direction. In the second motion converting mechanism, the second ball screw  34  rotates counterclockwise, so the second nut  33  moves to the left side in the drawing. 
         [0038]    Next, a die-slide device according to a modification of the first embodiment in which a first sprocket  23  and a second sprocket  22  are used instead of the first gear  23  and the second gear  22  in the die-slide device of the first embodiment will be described with reference to  FIG. 8 . In this example, since the first sprocket  23  and the second sprocket  22  are connected by one common chain  28 . Both rotate to the right. In the first motion converting mechanism, since the first ball screw  32  is a ring-handed screw and the first sprocket  23  rotates to the right, the first nut  31  moves in the left direction in the drawing. In the second motion converting mechanism, since the second ball screw  34  rotates to the right, in order to move the second nut  33  to the left toward the paper, the second ball screw  34  and the second nut  33  are left-handed screws. That is, the right- and left-handed screws of the first motion converting mechanism and the second motion converting mechanism have an important relationship with the rotating directions of the first sprocket  23  and the second sprocket  22 . 
         [0039]      FIG. 3  is a view of the location where the die-slide device  21  is attached to the main body of the extrusion press as seen from the container side. The die-slide device  21  is horizontally attached to the side opposite to the operating side of the extrusion press. The front end part  38  of the moving frame of the die-slide device  21  is slidably supported by the guide  18  fixed to the end platen  1  via the outer sliding member  40 . The die-slide device  21  is installed outside of the extrusion press, so maintenance is easier compared with the conventional case. Furthermore, the die-slide device  21  is extremely compact because it employs approximately twice the stroke of a conventional die-slide device. 
         [0040]      FIG. 4  shows a state in which the first motion converting mechanism and the second motion converting mechanism of the die-slide device  21  are actuated by being driven by the motor  25 . In this state, the die  4  is pushed by the pusher  37  to a location of a die changing device  70  outside of the extrusion press. By using the die-slide device  21  driven by a servo motor according to the first embodiment of the present invention, it is possible not only to speed up the operation for changing the die  4  but also to reduce the speed so as to reduce the shock before stopping—which is not easy in the case of the conventional hydraulic system. As a result, it also becomes possible to increase the maximum speed of movement of the die  4  to thereby increase the average speed. Therefore, the traveling time of the die  4  is shortened which leads to an improvement in productivity. 
         [0041]      FIG. 5  is a plan view showing the relationship between the die-slide device  21  of the extrusion press according to the first embodiment and the die changing device  70 . Note that, in  FIG. 5 , a cutting device  71  for cutting the extruded product is also shown. As shown in  FIG. 5 , the die  4  located at the center of the extrusion press is moved to the operation side from the center of the extrusion press by the die-slide device and set on the die changing device  70 . In the die changing device  70 , the die  4  is moved by the linear guide. The new die  4  stands by at the position B or C and the die to be changed is moved to the position A. After that, the die  4  to be changed is retracted to the position C when the new die  4  is standing by at the position B and to the position B when the new die  4  is standing by at the position C. Then, the new die  4  moves to the vacant position A, and the new die  4  and the die-slide device are connected. 
         [0042]      FIG. 6  shows the die-slide device  21  and the cutting device  71 . The cutting device  71  according to the present embodiment includes a hydraulic cylinder  72 , a pusher  73  fixed to a front end part of the same, and a bracket  74 . As shown in  FIG. 6 , a hydraulic cylinder  72  is attached to the end platen  1  via a bracket  74 . The cutting device  71  applies force to the die  4  together with the pusher  37  of the die-slide device  21  in order to cut the extruded product (not shown) extending continuously from the die  4  to the end platen  1  at the time of changing the die. The hydraulic cylinder  72  of the cutting device  71  operates to cut the extruded product, so it generates a greater force than the pusher  37  of the die-slide device  21 , but its stroke may be a short one of about 0.8 time the die diameter. Therefore, the hydraulic cylinder  72  may be relatively small. 
         [0043]    According to the die-slide device  21  and the cutting device  71  of the first embodiment, even if a small capacity cylinder is employed for the hydraulic cylinder  72  of the cutting device  71  and the time required for cutting by the die slide becomes slower than the past, there is a high possibility that the high-speed movement of the die-slide device  21  driven by a servo motor can make up for the delay. In this way, a hydraulic cylinder  72  having a small capacity can be used, so damage caused by the occurrence of oil leakage can be reduced. Furthermore, in this embodiment, a non-combustible oil is used as the hydraulic fluid of the hydraulic cylinder  72 , so it is possible to place the hydraulic cylinder  72  close to a high-temperature die or container. That is, the risk of igniting the hydraulic oil and causing a fire is remarkably reduced. 
         [0044]      FIG. 7  is a plan view showing an extrusion press die-slide device  21  and a cutting device  60  according to a second embodiment of the present invention. In the second embodiment, the die-slide device  21  is the same as that in the first embodiment, but the cutting device  60  is different from the cutting device  71  in the first embodiment. 
         [0045]    The cutting device  60  of the second embodiment is a servo motor driven type. It is configured so that when a servo motor  61  is driven, a pusher  66  moves leftward in  FIG. 7 . For this reason, the cutting device  60  comprises the servo motor  61 , a bearing  62 , a ball screw  63 , a nut  64 , a speed reducer  65 , the pusher  66 , two sprockets  67 ,  68 , and a mounting portion  69 . The cutting device  60  also comprises a chain wrapped between the sprocket  67  attached to the end of the drive shaft of the servo motor  61  and the sprocket  68  attached to the end of the ball screw  63 . When the servo motor  61  is driven, the ball screw  63  constrained in linear movement rotates, and as a result, the nut  64  constrained in rotation moves to the left, so the pusher  66  fixed to the nut  64  moves leftward. The cutting device  60  is fixed to the end platen  1  by its mounting portion  69 . 
         [0046]    The stroke of the pusher  66  of the cutting device  60  may be as short as about 0.8 time the die diameter, so the ball screw  63  may be a short one. 
         [0047]    An embodiment in which the servo motor  61  in the present embodiment is replaced with an inverter motor is also possible. 
         [0048]    Since the embodiments of the present invention have the above-described configurations, the following effects can be obtained. 
         [0000]    1) Since the die-slide device  21  has a structure in which two ball screws are combined in parallel, it is possible to realize a stroke equivalent to that of the conventional device by the approximately ½ shorter total length of the main body. Therefore, space saving of the equipment can be realized.
 
2) Since the die-slide device  21  is installed on the side opposite to the operating side outside the press machine which is not affected by the high temperature of the dies and containers, all the maintenance work can be performed outside the extrusion press machine and maintenance becomes easy.
 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1 . end platen 
           2 . main cylinder 
           3 . tie rod 
           4 . die 
           5 . container 
           6 . billet 
           7 . extrusion stem 
           8 . main crosshead 
           9 . main ram 
           10 . side cylinder 
           11 . side cylinder rod 
           12 . container holder 
           15 . die stack 
           16 . horseshoe 
           17 . die cassette 
           21 . die-slide device 
           22 . second gear 
           23 . first gear 
           24 . pulley 
           25 . motor 
           26 . moving frame 
           27 . linear guide device 
           31 . first nut 
           32 . first ball screw 
           33 . second nut 
           34 . second ball screw 
           35 . first bearing 
           36 . second bearing 
           37 . pusher 
           38 . slide block 
           39 . inside sliding member 
           40 . outer sliding member 
           42 . frame 
           61 . motor 
           62 . bearing 
           63 . ball screw 
           64 . nut 
           65 . speed reducer 
           66 . pusher 
           70 . die changing device 
           72 . hydraulic cylinder 
           73 . cutting jig