JP6357134B2 - Bimetal screw blank manufacturing system and manufacturing method - Google Patents

Description

  The present invention relates to a bimetal screw blank manufacturing system and a manufacturing method for manufacturing a bimetal screw blank.

  In recent years, various screws have been developed to meet various needs of users, and one of them is a bimetallic screw formed by joining dissimilar metals. In the bimetal screw, for example, stainless steel is used for the head and the shaft, and carbon steel is used for the tip, so that both corrosion resistance and ease of screwing can be achieved. In the bimetal screw, different metals are joined together, for example, by welding in the blank manufacturing stage before the thread portion machining (Patent Document 1).

Japanese Patent Publication No. 6-25564

  In Patent Document 1, resistance welding is used in the dissimilar metal joining in the bimetal screw, and burrs are generated at the joint. For this reason, the secondary process for removing a burr | flash is required before a thread part process, and there exists a problem that the number of manufacturing processes and manufacturing cost increase.

  The present invention has been made in view of the above problems, and provides a bimetal screw blank manufacturing system that does not generate burrs at joints of dissimilar metals and does not require secondary processing for deburring. Objective.

  In order to solve the above-described problems, the present invention provides a bimetal screw blank for manufacturing a bimetal screw blank by welding and joining a screw serving as a head and a shaft portion of a bimetal screw and a pin serving as a tip portion of the bimetal screw. In the manufacturing system, resistance welding means for joining only the central portion of the joint surface of the screw and the pin by resistance welding, and TIG welding means for joining the peripheral edge portion of the joint surface by TIG welding It is characterized by having.

  According to said structure, since only the center part of a joint surface is welded by resistance welding and the peripheral part of a joint surface is welded by TIG welding, the burr | flash in a joining location does not generate | occur | produce in the manufactured blank, but a thread part Secondary processing for removing burrs before processing becomes unnecessary, and the number of manufacturing steps and manufacturing cost can be reduced. Furthermore, since sufficient melt bonding is performed from the central portion to the peripheral portion at the bonding portion, sufficient strength can be ensured.

  Further, the bimetal screw blank manufacturing system includes a screw supply part for stocking the screw, a pin supply part for stocking the pin, the resistance welding means, and the TIG welding means. A welding apparatus that automatically welds the arranged screws and pins, and the screws and the pins are taken out one by one from the screw supply section and the pin supply section, and the predetermined position of the welding apparatus And a robot arm to be arranged on the robot.

  The bimetal screw blank manufacturing system and manufacturing method of the present invention does not generate burrs at joints in the manufactured blank, and does not require secondary processing to remove burrs before threaded processing. And there exists an effect that manufacturing cost can be reduced. Furthermore, since good melt-bonding is performed from the central portion to the peripheral portion at the joining portion, there is an effect that sufficient strength can be secured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a diagram illustrating a schematic configuration of a bimetal screw blank manufacturing system. It is a figure which shows each part before joining of a bimetallic screw, and the blank after joining. It is a perspective view which shows the structure of the screw supply part in the said system. It is a perspective view which shows the structure of the pin supply part in the said system. It is a side view which shows the structure of the screw feed slider in the welding apparatus of the said system. It is a side view which shows the structure of the pin feed slider in the welding apparatus of the said system. In the welding apparatus of the said system, it is a side view which shows the state of the resistance welding head vicinity at the time of welding. In the welding apparatus of the said system, it is a figure which shows the welding location and TIG welding head of a blank. It is a figure which shows the structure of the discharge part in the said system. (A) is sectional drawing of the welding location at the time of completion | finish of resistance welding, (b) is sectional drawing of the welding location at the time of completion | finish of TIG welding.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a bimetal screw blank manufacturing system (hereinafter referred to as the present system) 1 to which the present invention is applied, and shows the arrangement of functional units when the system is viewed from above. Yes. The system 1 includes a screw supply unit 2, a pin supply unit 3, a robot arm 4, a welding apparatus 5, and a discharge unit 6 as functional units. As shown in FIG. 2, the system 1 uses a screw 11 and a pin 12 as parts before joining, and joins these parts to produce a blank 10 for a bimetal screw. The screw 11 finally becomes the head and shaft of the bimetal screw, and the pin 12 becomes the tip of the bimetal screw. The screw 11 and the pin 12 are made of different metal materials. For example, the screw 11 can be a material with high corrosion resistance (for example, SUSSXM7), and the pin 12 can be a material with high heat resistance and strength (for example, SUS410).

  Hereinafter, each functional unit will be described in more detail.

  The screw supply unit 2 includes a screw feeder unit 21, a screw feed rail 22, and a turntable unit 23. The screw feeder 21 stocks a large number of screws 11, and the screw feeding rail 22 separates and feeds the screws 11 from the screw feeder 21 one by one. At this time, the screw 11 fed by the screw feeding rail 22 is fed in a vertical posture with the head portion 11a (see FIG. 2) on the upper side and the shaft portion 11b (see FIG. 2) on the lower side. The turntable unit 23 holds the screw 11 fed from the screw feeding rail 22 in a state where the robot arm 4 can easily grasp the screw 11.

  As shown in FIG. 3, the turntable portion 23 includes a disk-shaped table 23A that can rotate around a central axis, and a guard 23B that is disposed around the table 23A. Around the table 23A, a plurality (three in this case) of notches 231 for holding the screws 11 fed from the screw feeding rails 22 are provided. The notch 231 has a U-shape in which the outer peripheral side of the table 23A is opened as viewed from above, and the width thereof is smaller than the diameter of the head portion 11a of the screw 11 and larger than the diameter of the shaft portion 11b. For this reason, in each notch 231, it can hold | maintain in the state suspended with the head 11a of the screw 11 facing up.

  The screw 11 fed from the screw feeding rail 22 is held at a notch 231 at a position P in FIG. 3, and the table 23A rotates clockwise (in the direction of the arrow in the figure) to a position Q. Carried. The guard 23B prevents the screw 11 from falling during the movement from the position P to the position Q.

  The screw 11 carried to the position Q can be grasped by the robot arm 4 and pulled out from the notch 231 in the lateral direction (the outer peripheral direction of the turntable portion 23). Therefore, at the position Q, the notch 231 is prevented from dropping the screw 11 by the two elastic plates 232 instead of the guard 23B. The elastic plate 232 can prevent the screw 11 from dropping, but does not hinder the extraction of the screw 11 by the robot arm 4.

  The pin supply unit 3 includes a pin feeder unit 31 and a pin feed rail 32. The pin feeder unit 31 stocks a large number of pins 12, and the pin feeding rail 32 separates and feeds the pins 12 from the pin feeder unit 31 one by one.

As shown in FIG. 4, the pin feed rail 32 has a groove (for example, a V-groove) formed in the rail.
The pin 12 is fed along the line 321. At this time, the pin 12 fed by the pin feed rail 32 is fed in a horizontal posture in which the longitudinal axis of the pin 12 and the longitudinal direction of the groove 321 are parallel.

  The groove portion 321 comes into contact with the downstream side in the feed direction of the pin 12, and the leading pin 12 comes into contact with the downstream end of the groove portion 321 and stops. A part of the pin feed rail 32 below the top pin 12 is a movable block 322 that can move up and down. When the movable block 322 moves downward with the leading pin 12 hitting the tip of the groove 321, only the front and rear ends in the axial direction of the leading pin 12 are supported by the groove 321, and the vicinity of the center of the shaft is floating It becomes. In this state, the robot arm 4 can grasp and carry the leading pin 12. Thus, when the leading pin 12 is carried by the robot arm 4, the movable block 322 moves up to the original position and moves until the next pin 12 hits the tip of the groove 321.

  The robot arm 4 uses one arm mounted on the arm base 41 and two sub arms at the tip of the main arm. As a result, the screw 11 can be gripped from the turntable portion 23 by one sub arm and the pin 12 can be gripped one by one from the pin feed rail 32 by the other sub arm and moved to a predetermined position of the welding apparatus 5. Since the robot arm 4 can be a known robot arm manufactured and sold as an industrial robot, only the arm base 41 and the robot movement range are illustrated in FIG. 1, and the above-described main arm and sub arm are illustrated. Omitted. In the system 1, a robot arm (LR Mate 200ic) manufactured by FANUC is used as the robot arm 4.

  The welding device 5 includes a welding machine 51, a screw feed slider 52, and a pin feed slider 53. The welder 51 performs welding on the screw 11 and the pin 12, and the system 1 uses a welder manufactured by Osaka Denken. The screw feed slider 52 receives the screw 11 conveyed by the robot arm 4 at a predetermined position, and moves it to the welding position while holding it. The pin feed slider 53 receives the pin 12 conveyed by the robot arm 4 at a predetermined position, and moves it to the welding position while holding it.

  As shown in FIG. 5, the screw feed slider 52 includes a moving body 52A and an electric slider 52B. The moving body 52A is configured by fastening three holding plates 522, 523, and 524 to the main body 521 with screws or the like. The electric slider 52B is driving means for moving the moving body 52A in the horizontal direction between the standby position and the welding position. FIG. 5 shows a state where the moving body 52A is in the standby position. Further, the welding position is the position of the moving body 52A when the screw 11 and the pin 12 are welded together by the welding machine 51 (see FIG. 7).

  The holding plates 522, 523, and 524 have locations that are erected upward from the upper surface of the main body 521, and the erected locations are in order of the holding plates 522, 523, and 524 from the side closer to the welding position. . V-grooves 522a and 523a are formed at the upper ends of the above-mentioned standing positions of the holding plates 522 and 523, and the screw 11 is placed in the V-grooves 522a and 523a so that the screw 11 is in a horizontal posture (the screw 11 (A posture in which the axis is parallel to the horizontal direction). That is, the robot arm 4 places the screw 11 conveyed from the screw supply unit 2 on the V grooves 522a and 523a of the moving body 52A at the standby position. At this time, the head 11a of the screw 11 is on the side far from the welding position.

  As shown in FIG. 6, the pin feed slider 53 includes a guide rail 53A, a moving body 53B, and an electric slider 53C. The guide rail 53A has a V-groove 53Aa formed on the upper surface, and is a guide member for guiding the pin 12 placed on the V-groove 53Aa to the welding position. That is, the robot arm 4 places the pin 12 conveyed from the pin supply unit 3 at a predetermined position of the V groove 53Aa of the guide rail 53A. The moving body 53B moves the pin 12 placed in the V groove 53Aa to the welding position. The electric slider 53C is drive means for moving the moving body 53B in the horizontal direction between the standby position and the welding position. FIG. 6 shows a state immediately after the moving body 53B is at the standby position and the pin 12 is placed on the V-groove 53Aa by the robot arm 4.

  The moving body 53 </ b> B includes a main body 531, an extrusion bar 532, a spring 533, and a case 534. The push rod 532 is arranged so that its longitudinal axis is parallel to the longitudinal direction of the V-groove 53Aa, and pushes the pin 12 placed in the V-groove 53Aa at one end to the welding position and moves it. The spring 533 is disposed on the other end side of the push rod 532 and applies a biasing force in the welding position direction to the push rod 532. The case 534 holds the other end of the push bar 532 and the spring 533 inside.

  The welding machine 51 includes a resistance welding head (resistance welding means) 511 for resistance welding and a TIG welding head (TIG welding means) 512 (see FIG. 8) for TIG (Tungsten Inert Gas) welding. . FIG. 7 shows a state near the resistance welding head 511 during welding.

  The resistance welding head 511 has four electrodes 511a to 511d, and at the time of welding, a joint location (see FIG. 2) is arranged at the center of these four electrodes 511a to 511d. For this reason, in the screw feed slider 52, the moving body 52A moves from the standby position to the welding position, and moves the screw 11 to the welding position. At this time, as shown in FIG. 7, the screw 11 is positioned by the head portion 11 a coming into contact with the holding plate 524.

  In the pin feed slider 53, the moving body 53 </ b> B moves from the standby position to the welding position, and the pin 12 is pushed by the push rod 532 and moves to the welding position. The pin 12 is positioned by contact with the screw 11. At this time, the urging force of the spring 533 acts on the pin 12 via the push rod 532. The urging force of the spring 533 is a contact pressure at the welding location between the screw 11 and the pin 12.

  Of the four electrodes 511a to 511d, the lower electrodes 511c and 511d are stationary, but the upper electrodes 511a and 511b are movable in the vertical direction. The upper electrodes 511a and 511b are retracted upward except during welding, and descend when the screw 11 and the pin 12 are arranged at the welding position. Thus, during welding, the upper electrodes 511a and 511b sandwich the screw 11 and the pin 12 together with the lower electrodes 511c and 511d.

  More specifically, the electrodes 511a and 511c serving as screw-side electrodes sandwich the screw 11, and the electrodes 511b and 511d serving as pin-side electrodes sandwich the pin 12. Then, resistance welding is performed by passing an electric current along the axial direction through the welding portion between the screw 11 and the pin 12. Since the contact surface between the screw 11 and the pin 12 serving as a welded portion has a high resistance to the current, Joule heat is generated at this point, and the screw 11 and the pin 12 are melt-bonded.

  In the manufacturing process of the blank 10 by this system 1, TIG welding is performed following resistance welding. A TIG welding head 512 is used for TIG welding. In this system 1, as shown in FIG. 8, three TIG welding heads 512 (not shown in FIG. 7) are arranged around the welded portion of the screw 11 and the pin 12 at substantially equal intervals along the circumferential direction. Yes. That is, TIG welding is performed at three locations along the circumferential direction of the weld location.

  Each TIG welding head 512 has a tungsten electrode 512a at its tip, and an arc is generated between the tungsten electrode 512a and the base material (that is, the screw 11 and the pin 12) to melt the base material with arc heat. Let them weld. Further, the periphery of the tungsten electrode 512a is a nozzle 512b for releasing an inert gas (argon in this case), and the welding is performed in an inert gas atmosphere.

  When the welding (resistance welding and TIG welding) is completed, the upper electrodes 511a and 511b are raised to the retracted position, and the moving body 52A of the screw feed slider 52 and the moving body 53B of the pin feed slider 53 are returned to the standby position. At this time, the blank 10 in which the screw 11 and the pin 12 are joined moves together with the moving body 52 </ b> A when the head 11 a of the screw 11 is caught in the V groove 523 a of the holding plate 523.

  When the blank 10 is returned to the standby position together with the moving body 52A of the screw feed slider 52, the blank 10 is discharged to the outside of the system 1 by the discharge unit 6 as a finished product. As shown in FIGS. 1 and 9, the discharge unit 6 includes a pusher 61 and a discharge chute 62. The pusher 61 is horizontally movable in a direction orthogonal to the axial direction of the blank 10 with respect to the blank 10 in the standby position. In addition, an inclined surface 61a is formed at the front end (the blank 10 side) of the pusher 61 in the moving direction. For this reason, when the pusher 61 moves toward the blank 10, the blank 10 held by the holding plates 522 and 523 of the moving body 52 </ b> A is lifted along the inclined surface 61 a and pushed out to the pusher 61 and the opposite end side. .

  A discharge chute 62 is arranged below the side to which the blank 10 is pushed out. The blank 10 pushed out by the pusher 61 falls on the discharge chute 62, slides down on the discharge chute 62, and is discharged to the outside of the system 1.

  In this system 1, in order to manufacture the blank 10 which does not generate a burr | flash in a welding location, the following devices are performed in the welding method.

  First, welding is a two-stage process of resistance welding and TIG welding. In the resistance welding which is the previous process, welding of the entire joint surface is not performed, but only the central portion of the joint surface is welded. FIG. 10A is a cross-sectional view of a welded portion at the end of resistance welding, and a joining region by resistance welding is indicated by hatching.

  And the peripheral part of a joint surface is welded by TIG welding which is a post process. FIG. 10B is a cross-sectional view of the welded portion at the end of TIG welding, and the joining region by TIG welding is indicated by halftone hatching. Thus, the whole joint surface is welded by the joining area | region by resistance welding and the joining area | region by TIG welding. In addition, it is preferable that the joining area | region by resistance welding shall be 70 to 80% by the area ratio with respect to the whole joining surface, and the joining area | region by TIG welding is 30 to 40% by area ratio from a peripheral part so that it may melt | dissolve into a resistance welding area | region a little. (Area ratio) is preferable.

  In a conventional blank manufacturing process for a bimetal screw, only resistance welding is used for welding a screw and a pin. In resistance welding, welding is performed while applying pressure to a joint surface. For this reason, when the entire joint surface is melted during resistance welding, the molten metal protrudes in the circumferential direction by the pressure and becomes a burr. On the other hand, in the present invention, only the central portion is melted and joined without melting the entire joint surface during resistance welding. For this reason, there is almost no molten metal which protrudes in the circumferential direction by the said pressure.

  In the present invention, in order to weld only the central portion of the joint surface by resistance welding, it is necessary to appropriately control the welding time (that is, the current application time). The appropriate welding time in the present invention varies depending on various conditions such as the diameter of the welded part, the base material, and the applied pressure, but the welding time corresponding to each of these conditions should be obtained by experiments and the like in advance. Is possible.

  In TIG welding, the molten metal is automatically embedded inside, so that a beautiful finished surface without burrs can be obtained. In addition, when welding with a screw and a pin only by TIG welding, although the peripheral part of a joint surface can be joined, the center part cannot fully join but sufficient intensity | strength in a joining location is not acquired.

  As described above, in the welding joint using the present system 1, only the central part of the joint surface is welded by resistance welding, which is a previous process, and the peripheral part of the joint surface is welded by TIG welding, which is a subsequent process. Thereby, the burr | flash in a joining location does not generate | occur | produce in the blank 10 manufactured, the secondary process for removing a burr | flash before a thread part process becomes unnecessary, and can reduce the number of manufacturing processes and manufacturing cost. Furthermore, since sufficient melt bonding is performed from the central portion to the peripheral portion at the bonding portion, sufficient strength can be ensured.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Bimetal screw blank manufacturing system 2 Screw supply part 3 Pin supply part 4 Robot arm 5 Welding device 6 Discharge part 10 Blank 11 Screw 12 Pin 21 Screw feeder part 22 Screw feed rail 23 Turntable part 31 Pin feeder part 32 Pin feed Feed rail 51 Welding machine 52 Screw feed slider 53 Pin feed slider 511 Resistance welding head (resistance welding means)
512 TIG welding head (TIG welding means)

Claims (3)

A bimetal screw blank manufacturing system for welding a bimetal screw head and a shaft portion and a bimetal screw tip to weld and joining the bimetal screw blank,
Resistance welding means for joining only the central portion of the joint surface by resistance welding at the joint surface of the screw and the pin;
A bimetal screw blank manufacturing system comprising: TIG welding means for joining peripheral edges of the joining surfaces by TIG welding. A bimetal screw blank manufacturing system according to claim 1,
A screw supply unit for stocking the screws;
A pin supply unit for stocking the pins;
A welding apparatus having the resistance welding means and the TIG welding means, and automatically welding the screw and the pin arranged at a predetermined position;
A bimetal screw blank manufacturing system comprising: a robot arm that takes out the screw and the pin one by one from the screw supply unit and the pin supply unit and places the screw and the pin at the predetermined position of the welding apparatus. . A bimetal screw blank manufacturing method for welding a bimetal screw head and a shaft part and a bimetal screw tip to be welded and manufacturing a bimetal screw blank,
A resistance welding step of joining only the central portion of the joint surface by resistance welding at the joint surface of the screw and the pin;
A bimetal screw blank manufacturing method, comprising: a TIG welding step of joining peripheral edges of the joint surfaces by TIG welding.

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