JP3289128B2 - Method and apparatus for producing a burr-free welding ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION After coiling a wire into an annular body, the end of the annular body is cut off from the wire, the cut surface of the annular body is welded into a weld ring, and the weld bead at the weld is crushed. And a method and apparatus for producing a weld ring without burrs.

[0002]

2. Description of the Related Art A welding ring manufactured by welding a cut surface of an end portion of an annular body coiled from a wire by a conventional technique is required to remove weld beads protruding from the inner and outer peripheries of a welded portion and upper and lower surfaces. was there. For this reason, it is the present condition that the weld bead is manually removed from the welded portion of the weld ring using a file, a belt grinder, or the like.
An apparatus for automatically removing a weld bead of a welding ring having a relatively small diameter of about m to 50 mm has not been developed. Therefore, a known apparatus capable of removing a weld bead regardless of the size of the ring is a polishing apparatus for a grooved ring having a cross section disclosed in Japanese Utility Model Laid-Open Publication No. 64-16258.

As shown in FIG. 18, four tongue tables 210a to 201d for attaching a jig are arranged at equal pitches above an outer peripheral portion of a main tongue table 202 which can be indexed by 90 °. When one jig of the tongue table 202 stops at the ring engaging / disengaging position, each ring 204 fitted at the upper end of each of the other jigs 203a to 203d provided at the other three jig stopping positions is roller 205. To rotate the tontables 201a to 201d to grind the inner surface, upper surface and outer surface of the ring by the rotation of the inner grindstone 206a, the upper grindstone 206b, and the outer grindstone 206c and the axial advance / retreat swing.

[0004]

The method for manually removing a weld bead described in the prior art is time-consuming and labor-intensive, and is inefficient, and particularly the inner and outer peripheries of the welding ring are non-linear. For this reason, there is a problem that the surface is not finished beautifully after the welding beat is removed, and the product value is reduced. Further, the method of removing a welding beat using a dedicated device such as a polishing device disclosed in Japanese Utility Model Application Laid-Open No. 64-16258 has a low productivity because a device for manufacturing a welding ring and a device for polishing burrs are separated. However, there is a problem that the production cost increases because much labor is required. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to eliminate a step of shaving off a welding bead (burr) generated by welding and to reduce a man-hour. An object of the present invention is to provide a method and an apparatus for manufacturing a welding ring.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, a method for manufacturing a burr-free welding ring according to the present invention comprises the steps of: abutting a wire having a square cross section with a forming member to form a coiled body; The cutting edge cross section is cut off from the wire by cutting the end of the annular body with a drum-shaped cutting punch and a cutting die, and the inner and outer corners of the cut surface are chamfered. The annular body is butt-welded so that the weld bead does not protrude from the V-shaped recess formed by chamfering the inner and outer circumferences of the abutting portion with the upper and lower surfaces abutting on the same plane to form a welding ring,
The welding ring is pressed into a hole having the same diameter as the outer diameter of the forming die when the welding ring is completed by a pressing punch to form a perfect circular shape, and the upper end surface of the knockout punch is formed in the hole of the forming die. And pressing the upper and lower surfaces of the welding ring between the upper and lower surfaces of the pressing punch to crush the welding beads protruding from the upper and lower surfaces to make the upper and lower surfaces flat.

[0006] In addition, an apparatus for manufacturing a burr-free welding ring includes:
A device that manufactures a burr-free welding ring from a wire with a square cross section, a coiling mechanism that abuts a linear wire fed from a quill on a forming member to form an annular body, and a cutting blade section for chamfering. The end of the annular body is cut by a cutting punch having a bevel shape formed into a drum shape having a slope and a cutting die having a hole formed in a drum shape into which the tip of the cutting punch can be fitted. A cutting mechanism for chamfering the inner and outer corners of the cut surface with a slope, and the upper and lower surfaces of the cut surface facing the cut annular body abutting on the same plane to form the inner and outer peripheries of the contact portion by the chamfering. A welding mechanism that butt-welds the annular body to form a welding ring so that the welding bead does not project from the formed recess; a forming die having a hole having the same outer diameter as the completed welding ring; Respectively positionable knockout punch and positions the upper end face to be vertically movable through the hole in the die pushes the weld ring to said forming die outside the position for pressing in the forming die, and the lower end face the knockout punch A press punch which is vertically opposed to the tip end thereof is inserted into the hole of the forming die, and presses the welding ring with the press punch to fit into the hole of the forming die to form a round shape. A surface pressing mechanism that presses the welding ring with the pressing punch and the knockout punch to crush the welding bead projecting up and down to make it a flat surface without burrs, and positions the workpiece at a position where each of the mechanisms is disposed. And a work transfer mechanism.

The forming member of the coiling mechanism may be a plurality of rotatable forming rollers.

Further, after the face pushing mechanism, a side plug gauge portion whose tip portion has the same size as the allowable minimum inner diameter of the welding ring,
An inspection mechanism comprising a vertically movable stopper gauge member formed in the order of a stop-side stopper gauge portion having the same size as the allowable maximum inner diameter and a detecting means for detecting the quality of the inner diameter based on the vertical position of the stopper gauge member. In other words, the inner diameter of the welding ring can be inspected.

According to the method and apparatus for manufacturing a burr-free welding ring of the present invention, (1) the wire is coiled into an annular body and then cut while the work transfer mechanism makes a round around the position where each mechanism is arranged; (2) Weld the cut opposing surfaces to form a weld ring, (3) Form the outer diameter into a perfect circle and crush the weld beads protruding on both sides, (4)
Since the inspection of the inner diameter is performed, continuous production becomes possible, thereby improving the productivity and reducing the manufacturing cost.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the entire burr-free welding ring manufacturing apparatus as viewed from the direction of the arrows BB in FIG. 2, and FIG. FIG. 1 and 2, the upper surface of the upper plate (bolster) 1a of the frame 1 installed on the floor is formed on the bolster surface 1b, and four guides are provided at four corners of the upper plate 1a and the shelf 1c in the frame, respectively. A post 3 is provided to be movable vertically in the axial direction, and a ram 4 is fixed to the upper end of the four guide posts 3 in parallel (horizontal) with respect to the bolster surface 1b.

A cam shaft 5 is horizontally and rotatably mounted at a lower position of the frame 1, and an eccentric cam 6 is keyed at the center of the cam shaft 5, and the cam shaft 5 projects from the frame 1. A large gear 7 is attached to the right end, and a pulley 9 for driving an indexing unit 8 to be described later is keyed to a left end protruding from the frame 1.

A drive motor 10 is installed on the rear floor of the frame 1, and an intermediate shaft 11 is rotatably supported at the rear of the frame 1 in parallel with the cam shaft 5.
1 has a large pulley 12 also serving as a flywheel at the right end,
A small gear 13 meshing with the large gear 7 is keyed on the left side. A belt 15 is stretched between a small pulley (not shown) keyed to the output shaft of the drive motor 10 and the large pulley 12.

An upper beam 16 and a lower beam 17 are fixed to the lower ends of the four guide posts 3 with the eccentric cam 6 interposed therebetween.
The cam followers 24 and 25 are rotatably supported by the upper beam 16 and the lower beam 17, respectively.
The upper and lower eccentric cams 6 sandwich the upper and lower eccentric cams 6 without any gap, and the ram 4 moves up and down one stroke via the guide posts 3 by one rotation of the camshaft 5.

The indexing unit 8 is fixed to the lower surface in front of the upper plate 1a of the frame 1 so that the output shaft 8a projects vertically from the bolster surface 1b, and a circular index table 18 is provided at the upper end of the output shaft 8a. Is keyed. The input shaft 8b of the indexing unit 8 is connected via a coupling 21 to a rotating shaft 19 that is rotatably supported concentrically on the frame 1, and the pulley 22 keyed to the left end of the rotating shaft 19 is connected to the input shaft 8b. Belt 2 between pulley 9
3 is stretched.

The indexing unit 8 is divided into eight equal parts, and the index table 18 is indexed at equal intervals of 45 ° by one rotation of the camshaft 5, that is, one stroke of the ram 4, on the bolster surface 1b. Is provided with eight indexing positions from a first station a to an eighth station around the index table 18, and a coiling mechanism and a cutting mechanism to be described later near the first station a.
A welding mechanism described below is provided near the fourth station d, a surface pushing mechanism described later is provided near the fifth station e, an inspection mechanism described later is provided near the sixth station f, and a work discharge mechanism described later is provided near the seventh station g. Each is installed. Each of the second, third and eighth stations is an idle station.

FIG. 3 is a cross-sectional view of the coiling mechanism 31 and the cutting mechanism 40 provided in the vicinity of the first station a as seen from the direction of arrows EE in FIG. 4, and FIG. FIG. 5 is a sectional view taken along the line DD of FIG. 3. Also,
6 is a cross-sectional view taken along the line HH of FIG. 3 when the cutting mechanism 40 is viewed from the front, FIG. 7A is a cross-sectional view taken along the line FF of FIG.
FIG. 7B is a view taken along the line GG in FIG. 6.

As shown in FIGS. 1 and 2, a wire feeder 26 is fixed to the left side of the upper plate 1a of the frame 1 as shown in FIGS.
7A and 27B are rotated by an NC-controllable servomotor 28 fixed vertically and upward to the lower surface of the wire feeder 26. A horizontal line in the left-right direction passing between the feed rollers 27A and 27B is set as a wire feed line for the wire Wa, and a plurality of rotatable straightening rollers are arranged before and after the feed rollers 27A and 27B. A straightener 29A for correcting the widthwise bending of the wire Wa, and a second straightener for correcting the thicknesswise bending of the wire Wa by disposing a plurality of rotatable straightening rollers above and below the wire feed line. 9B.

The cross-sectional shape of the wire Wa intermittently fed by the feed rollers 27A and 27B is such that when the wire Wa is formed into an annular shape, the side to be the outer peripheral portion is preliminarily set so that the outer peripheral portion and the inner peripheral portion have the same thickness. Thicker than the inner peripheral side,
It has a trapezoidal shape that is indistinguishable to the naked eye, and is sent out to the coiling mechanism 31 through a hole in the quill 30.

The coiling mechanism 31 is, as shown in FIG.
A wire rod is formed on the outer periphery of a rotatable core roller 32 which abuts on the inside of the formed annular ring Wb and two rotatable forming rollers 33 and 34 which abut on the outside of the annular ring Wb. A known grooved guide groove is formed, and the cored bar roller 32 has a bolster surface 1b as shown in FIG.
A cylindrical holder 38 fixed on a substrate 35 fixed thereon.
Are vertically and rotatably supported via a rotation shaft 32a, and the forming rollers 33 and 34 shown in FIG.
Square holders 36 and 3 fixed so as to be position adjustable above
7 and fixing pins 39, 39 fitted vertically (FIG. 5)
Is rotatably supported at the upper end of the head.

Accordingly, the wire Wa intermittently fed from the hole of the quill 30 is formed into an annular coil by abutting against the forming rollers 33 and 34. As shown in the figure, during continuous molding, the wire Wa leaving an arc portion of approximately 1/2 circle shown in FIG. 17 (a) at the tip end is further coiled for one turn as shown in FIG. 17 (b). An annular ring Wb for approximately 1.5 turns is formed.

On the other hand, as shown in FIG. 6, the cutting mechanism 40 has a cutoff table 41 attached to the front end of the bolster surface 1b at a position corresponding to the first station a.
The die set lower base 43 side of the cutting die set 42 is fixed on the upper side. The guide post 4 is provided on the die set lower base 43.
4 and 44, two guide posts 4
A die set upper base 45 is provided to be able to move up and down along 4 and 44.

Then, as shown in FIG. 7B, a cutting die 47 having a drum-shaped hole 47a is detachably attached to the die set lower base 43 via a die holder 46, and the die set upper base 45 A cutting punch 49 is fixed to the lower surface of the cutting punch 49 via a punch holder 48 in a downward direction.
The cutting blade 9 is shaped like a drum as shown in FIG. 7A, and can be inserted into the hole 47a of the cutting die 47.

Further, on the lower side of the punch holder 48, as shown in FIGS. 6 and 7 (a), a work holding plate 51 having four guide pins 52, 52, 52, 52 in the vertical direction.
The work holding plate 51 is constantly urged downward by two springs 50 and 50 and is formed at the upper end of two positioning pins 53 provided at the center of the spring 50. The lower limit position is regulated by the provided lower surface of the flange.

The die set upper base 45 is provided on the first side of the front side of the ram 4.
Cut-off holder 54 fixed at position corresponding to station a
Is connected to the lower plate 54a by a connection bolt 55,
When the die set upper plate 45 is lowered with the lowering of the ram 4, the work holding plate 51 first comes into contact with the upper surface of the annular ring Wb, and the annular ring Wb is pressed downward by the force of the spring 50 to be fixed. I have. The work holding plate 5
As shown in FIG. 6, the lower surface shape of the
The wound portion and the two-turn portion are formed in a step so that they can abut.

Here, the work transfer table jig 56 attached to the outer periphery of the index table 18 shown in FIG. 2 will be described. As shown by phantom lines in FIG. 3, the table jig 56 is mounted on a substrate 57 on which eight identical units are fixed on the circumference of the index table 18 at equal intervals and at the same distance from the rotation center of the index table 18. As shown in FIG. 8, an upper plate 58 and a lower plate are mounted on upper and lower ends of two guide pins 61 which are vertically movably inserted into the distal end of a substrate 57 fixed on the index table 18. 59 are respectively fixed. And
Springs 62, 62 are mounted between the substrate 57 and the upper plate 58, and the frame structure including the upper plate 58, the lower plate 59, and the guide pins 61, 61 is constantly urged upward. An adjust bolt 63 for determining an upper position of the frame structure is screwed to the center of the frame.

Further, a pair of holding arms 6 formed in a symmetrically bent shape between the lower surface of the lower plate 59 and the back plate 59a.
4A and 64B are supported by pivot pins 65 and 65 so as to be openable and closable in a horizontal plane, and the holding arms 64A and 64B are always closed and urged by a relatively weak spring 67. Then, gripping claws 66A, 66B for gripping the outer peripheral portion of the annular ring Wb are provided below the distal ends of the holding arms 64A, 64B.
Is fixed, and the work gripping surfaces 66 of the gripping claws 66A and 66B are fixed.
A chamfer 66b is provided at the lower corners of the a and 66a so that the work can be easily inserted. The pin 60 is a holding arm 64
A, 64B determine the minimum closed position.

Further, as shown in FIGS. 1 to 4, the support shaft 6 is mounted on the upper end surfaces 2a, 2a of the bearing housings 2, 2 which incorporate the bearings for the two guide posts 3, 3 on the front side on the bolster surface 1b.
A cross beam 69 is attached via 8, 68.
An air cylinder 71 for lifting and lowering the table jig 56 is attached downward at a position corresponding to the upper first station a. The piston rod 72 of the air cylinder 71 penetrates the cross beam 69 and projects downward.
The lower end surface of the adjust nut 73 is in contact with the center of the upper plate 58 of the table jig 56 indexed to the first station a.

In the table jig 56 indexed to the first station a, the gripping claws 66A, 66B fixed to the holding arms 64A, 64B by the air cylinder 71 resist the forces of the springs 62, 62 from the upper position. To move downward, and the workpiece gripping surfaces 66a, 66B of the gripping claws 66A, 66B.
chamfered portions 66b, 66b provided at the lower corners of a
When the outer circumference of the annular ring Wb comes into contact with the
So that the pushes and opens the spring 67 to grip the annular ring Wb by slopes 6b, 66 b.

Therefore, at the first station a, the wire Wa having a rectangular cross section is intermittently fed by the feed rollers 27A and 27B, and is coiled on the annular ring Wb by the inner core roller 32 and the outer forming rollers 33 and 34. After being formed, the work holding plate 51 is used to form an annular ring Wb.
Is pressed downward, the outer periphery of the annular ring Wb is gripped by the gripping claws 66A and 66B, and the annular ring Wb is separated from the wire Wa by the cutting punch 49 and the cutting die 47, as shown in FIG. To annular ring W
The chamfered portions Wc, Wc are formed at the inner and outer peripheral corners of b. The chamfered portions Wc, Wc are formed so that a V-shaped concave portion (a groove portion) can be formed in advance so that a weld bead formed at the time of welding described later does not protrude from the inner and outer peripheral surfaces of the annular ring Wb.

A welding mechanism 76 is provided at the fourth station d shown in FIG. 9A is a sectional view taken along the line MM of FIGS. 1 and 10 showing the welding mechanism 76, FIG. 9B is a sectional view taken along the line PP of FIG. 9A, and FIG. FIG. 10 is a cross-sectional view taken along the line NN of FIG. As shown in FIG. 1, the base 77 of the welding mechanism 76 is fixed to the periphery of the fourth station d on the bolster surface 1b with an inclination of approximately 45 ° with respect to the side surface of the upper plate 1a. A fixed stand 78 is erected on the 5 station e side.

One upper slide 81 is provided on the inner surface of the fixed stand 78 via a linear slide 79 so as to be vertically movable, and a seat plate 82 is fixed to a corresponding position on the lower surface of the ram 4. The core bar 83 and the positioning pin 84 are provided vertically, respectively. A relatively strong spring 85 is mounted between the stepped hole 81 a formed in the upper slide 81 concentrically with the spring mandrel 83 and the tip end of the spring mandrel 83, and the lower end of the positioning pin 84. Is inserted into the stepped hole 81b of the upper slide 81 so as to be vertically movable,
The upper slide 81 is constantly urged downward by a spring 85, and the flange 83a at the lower end of the positioning pin 81 has a stepped hole 8a.
The lower end position of the upper slide 81 is determined by contacting the step end surface of the upper slide 1b.

A fixing base 86 is fixed on the base 77 directly below the upper slide 81, and an electrode base 88 is fixed on the fixing base 86 via an insulating pad 87.
A fixed electrode 89 is fixed thereon with the work contact surface facing upward. An insulating pad 91 is fixed to the lower surface of the upper slide 81, a nail base 92 is fixed to the lower surface of the insulating pad 91, and a pressing claw 93 is fixed to the lower surface of the nail base 92 so as to face the fixed electrode 89. . The electrode base 88 and the claw base 92 are provided with flow paths 88a and 92a for cooling water, respectively, and an annular ring Wb is formed on the lower surface of the pressing claw 93 as shown in FIG. An arc-shaped non-slip groove 93a is formed in contact with the groove.

Further, a third station c on the base 77
A linear slide 94 is provided at a right angle to the inner surface of the fixed stand 78, and an L-shaped movable stand 95 is movably provided on the linear slide 94.
A linear slide 96 is provided on the inner surface of the movable stand 95 in the up-down direction, and the other upper slide 97 is fixed to the linear slide 96 so as to be vertically movable.
The cylinder mount 98 is fixed to the upper surface of the cylinder 5. An air cylinder 99 is fixed vertically and downward on a cylinder mounting base 98, and a through hole through which the air cylinder 99 can be inserted is provided in the ram 4, and a lower end of a piston rod 99a of the air cylinder 99 slides upward. 97 and a connecting tool 101.

An insulating pad 104 is fixed on the bottom 95 a of the moving stand 95, an electrode base 105 is fixed on the insulating pad 104, and the moving electrode 106 has the same height as the fixed electrode 89 on the electrode base 105. It is fixed.
An insulating pad 107 is also fixed to the lower surface of the upper slide 97, a claw base 108 is fixed to the lower surface of the insulating pad 107, and a pressing claw 109 is attached to the lower surface of the claw base 108.
06 and is fixed.

The electrode base 105 and the nail base 108 are provided with cooling water passages 105a and 108a, respectively.
An arc-shaped non-slip groove 109a is formed in contact with the groove. Further, a stand 111 is fixed near the linear slide 94 on the end of the third station c on the base 77, and the air cylinder 112 is fixed to the stand 111 horizontally and facing the movable stand 95 side.

The distal end of the piston rod 112a of the air cylinder 112 is connected to the moving stand 95 by a connecting bolt 115. The moving stand 95 is moved by the air cylinder 112 to a position where the welding is completed on the fixed stand 78 and on the opposite side of the fixed stand 78. And the standby position.

Therefore, at the fourth station d,
An annular ring Wb formed by coiling at the first station a and separated from the wire Wa is gripped by the gripping claws 66A and 66B of the table jig and indexed to the fourth station d via the second and third idle stations. When
The ram 4 descends and the holding claws 66A, 6 of the table jig 56 are moved.
A portion near one cut end surface Wd of the annular ring Wb gripped by 6B is pressed against the upper surface of the fixed electrode 89 by a force of a spring 85 by a pressing claw 93 and held.

Next, the upper slide 97 is lowered by the air cylinder 99 so that the annular ring W
After pressing the vicinity of the other end surface Wd of b with the pressing claw 109 to hold the upper and lower surfaces flush with the fixed electrode 89 side, the rear chamber of the air cylinder 112 (the chamber on the side opposite to the movable stand 95)
The pressurized air is supplied to the movable stand 95 from the standby position at the retreat end to the fixed stand 78 side, and the annular ring Wb
Are opposed to each other, and a voltage is applied between the electrodes 89 and 106 to perform butt welding.

By this butt welding, the opposite end face Wd of the annular ring Wb is melted by the above-mentioned welding and the circumferential length is shortened to form an elliptical welding ring Wf as shown in FIG. As shown in FIG. 17 (c), the raised weld bead We fits in a V-shaped recess (groove) formed by chamfers Wc, Wc provided on the inner and outer circumferences of the annular ring Wb,
The raised weld bead We protrudes from the upper and lower surfaces. In this state, the moving stand 95 stops, the applied voltage is cut off, and the butt welding ends.

Next, pressurized air is supplied to the lower chamber of the air cylinder 99 to raise the upper stand 97, and at the same time,
Rises, and the pressing claws 93 and 109 are separated from the welding ring Wf. Then, the pressurized air is supplied to the front chamber of the air cylinder 112, and the moving stand 95 retreats to the non-fixed stand 78 side to stand by. I have.

The fifth station e shown in FIG. 1 is provided with a surface pushing mechanism 124. FIG. 11 shows a surface pushing mechanism 12.
4 is a sectional view taken along the line JJ of FIG. 1 showing a state before surface pressing, and FIG. 12 is a sectional view taken along the line JJ of FIG. FIG. The surface pressing mechanism 124 is a pressing punch 12 provided on the ram 4.
5, a forming die 126 provided concentrically with the pressing punch 125 on the bolster surface 1b, and a knockout punch 1
27, and the forming die 126 has a hole 126a having the same size as the outer diameter of the weld ring Wf when the welding ring Wf is completed.
Elliptical distorted weld ring W with welds finished at the mouth
A chamfered portion 126b for pressing and fitting f is provided.

The pressing punch 125 has an upper and lower position adjusting screw 125b engraved on an upper portion thereof. The screw 125b is screwed into a screw hole 4c engraved on the ram 4 so that the vertical position can be adjusted. ing. A lock nut 128 for fixing the vertical position after the vertical position adjustment is screwed.
26a.

The knockout punch 127 is used for the forming die 12.
6 is movably inserted into a stepped hole including a hole 126a, and is constantly urged upward by a relatively strong spring 129. The upper end surface 127a of the knockout punch 127 is at the upper limit position of the forming die 126. The upper end surface 126c has substantially the same height, and the lower end surface 125a and the upper end surface 127a of the pressing punch 125 descending with the ram 4 at this position sandwich the welding ring Wf and fit into the hole 126a of the forming die 126 to have an outer diameter. Into a perfect circle.

As shown in FIG. 12, the lower end surface 127b of the knockout punch 127 contacts the bolster surface 1b to prevent the knockout punch 127 from descending, and the upper end surface 127a is positioned below the upper end surface 126c of the forming die 126. Then, the lower end surface 125a of the forming punch 125
The gap between the upper end surface 127a of the knockout punch 127 and the thickness of the completed weld ring Wf is the same as the thickness of the weld ring Wf, and the weld bead We projecting from the upper and lower surfaces of the weld ring Wf is crushed. Finish on the same plane without any.

When the ram 4 is lifted, the welding ring Wf, which has been formed into a perfect circle and has no burrs, is pushed up by the knockout punch 127 by the force of the spring 129, and is pushed out from the hole 126a of the forming die 126. It is held at the mouth of the gripping claws 66A and 66B of the table jig 56, and after the fifth station pin, it is slid on the guide plate 131 shown in FIGS. 1, 13 and 15 provided on the bolster surface 1b and conveyed. It is supposed to be.

An inspection mechanism 135 is provided at the sixth station f shown in FIG. FIG. 13A is a vertical sectional view of the inspection mechanism, taken along the line KK in FIG. 1, FIG. 13B is a top view of FIG. 13A, and FIGS. 13 is an enlarged view of a portion surrounded by a virtual circle L in FIG. 13, and FIG. 13D is an enlarged view of a plug gauge described later. Guide plate 1 fixed on bolster surface 1b via leg 132
A hole 131a larger than the inner diameter of the welding ring Wf by about 0.5 mm is penetrated vertically at a position corresponding to the sixth station f of the base 31, and a support sleeve 136 is vertically fitted in the ram 4 concentrically with the hole 131a. Is being worn. An inspection shaft 137 is vertically movably fitted into a center hole of the support sleeve 136, and the inspection shaft 137 is constantly urged downward by a spring 138, and a plug gauge 139 is fitted concentrically at the lower end.

A stripper 141 is fitted to the outer periphery of the lower part of the inspection shaft 137 and the stopper gauge 139 so as to be vertically movable, and a spring 142 is interposed between the upper end of the stripper 141 and the lower end of the support sleeve 136. And stripper 1
41 is constantly urged downward by a spring 142, and the plug gauge 139 before the ram 4 descends is in a state of being immersed in the hole of the stripper 141.

An outer peripheral groove 143 for transmitting the fiber light is provided on an upper portion of the inspection shaft 137 projecting from an upper end of the support sleeve 136.
A slit collar 143 having a is fitted concentrically. An L-shaped support 144 is fixed near the support sleeve 136 on the upper surface of the ram 4, and a light emitting portion 146A and a light receiving portion 146B of the photoelectric detector 146 are provided on both ends of the support 144 via the arms 145 and 145. 143 are provided to face each other.

As shown in the enlarged view of FIG. 14D, the plug gauge 139 has an outer diameter dimension v whose tip step 139a is the same as the minimum dimension of the inner diameter tolerance when the welding ring Wf is completed.
And a step portion 139b thereon is formed to have the same outer diameter dimension u as the maximum dimension of the inner diameter allowable error range. The upper portion 139c is formed to have an outer diameter dimension w larger than the maximum dimension u, and the step portion 139c having the outer diameter dimension w cannot be inserted into a hole larger than the maximum dimension.

Therefore, at the sixth station f, the guide plate 1 is moved by the table jig 56 from the fifth station e.
The welding ring Wf conveyed so as to slide on the
When it is positioned concentrically with 31 a, the inspection mechanism 135 is lowered by the lowering of the ram 4, the lower end of the stripper 141 contacts the upper surface of the welding ring Wf, and the welding ring Wf is pressed onto the guide plate 131 by the force of the spring 142. Then, the plug gauge 139 tries to face the hole of the welding ring Wf by the force of the spring 138.

At this time, if the inner diameter of the welding ring Wf is smaller than the minimum diameter v of the allowable error range, as shown in FIG. 14C, the insertion of the tip step 139a of the plug gauge 139 is impossible, and the slit collar 143 is not provided. Is located above the fiber light X of the photoelectric detector 146, the fiber light X from the light emitting unit 146A is shielded and does not reach the light receiving unit 146B.

When the inner diameter of the welding ring Wf is larger than the maximum diameter u for the allowable error range, as shown in FIG. 14 (a), a step 139a at the tip of the plug gauge 139 and a step 139b following it can be inserted. Since the outer circumferential groove 143a of the slit collar 143 is located below the fiber light X, the fiber light X from the light emitting unit 146A is blocked and does not reach the light receiving unit 146B. Thus, at the time of measurement (when the ram 4 is near the lower end position), the fiber light X is transmitted to the light receiving unit 1.
If the light does not enter 46B, it is determined to be defective without a detection signal from the photoelectric detector 146 and stored in the NC device.

When the inner diameter of the welding ring Wf is within the allowable error range, the tip step 13 of the plug gauge 139 is not required.
9a can be inserted, and the following step portion 139b cannot be inserted.
43a coincides with the fiber light X of the photoelectric detector 146, the fiber light X can pass through, and the fiber light X enters the light receiving unit 146B. Then, a detection signal is output from the photoelectric detector 146, sent to the NC device, and stored as a non-defective product. Then, it sorts non-defective products and defective products stored in a discharge mechanism 150 described later.

A work discharge mechanism 150 is provided at the seventh station g shown in FIG. FIG. 15 is a top view of the work discharge mechanism 150, and FIG. 16 is a view taken in the direction of the arrow R in FIGS. A leg 151 on the bolster surface 1b and a support 1 on the side surface of the upper surface 1a of the frame 1 adjacent to the end of the guide plate 131
A chute 153 is erected by the first and second members. The chute 153 has an inclination angle at which the welding ring Wf can slide down,
An auxiliary chute 154 having a U-shaped cross section and having a larger inclination angle is attached to the end of the chute 153 by a support 170 at the tip of a shelf 172 fixed to the side surface of the frame 1. The bottom plate 153a of the starting end of the chute 153 (the position below the welding ring Wf conveyed to the seventh station g) is cut out and opens vertically, and the leg 15
1 is a shutter device 15 for opening and closing the notch 153b.
5 are provided.

The shutter device 155 drives a frame 156 having an air cylinder 158 in a direction perpendicular to the work sliding direction of the chute 153, a shutter 157 movable back and forth along the guide of the frame 156, and a shutter 157. An air cylinder 158, and the air cylinder 158
The shutter is retracted and opened only when the defective welding ring Wf stored in the C device comes. Further, the chute 153 has a bottom plate 153a near the end.
Are cut out and open up and down.
A door device 159 that opens and closes 3c is provided.

The door device 159 is a swingable door 16.
1 and an air cylinder 162 for driving this,
The opening / closing door 161 is swingably supported on the bottom surface of the chute 153 by a pin 163, and when closed, the upper surface 161 is closed.
a is flush with the upper surface of the bottom plate 153a. The air cylinder 162 has a support 164 fixed to the side of the chute 153.
And a swingable support 165 fixed to the opening / closing door 161 to position the opening / closing door 161 between the closed position and the open position.

Further, a gate bar 166 for thickness measurement is fixed between the both sides of the chute 153 near the opening / closing door 161 at right angles to the work sliding direction and parallel to the bottom plate 153a. Opening and closing door 161
Of the chute 153 is set so that a gap between the bottom plate 153 and the upper surface of the chute 153 becomes the maximum allowable value of the thickness of the welding ring Wf.
a If the thickness of the welding ring Wf sliding down the upper surface is larger than the maximum allowable value, the welding ring Wf comes into contact with the gate rod 166 and stops.

Further, a light-emitting portion 169A and a light-receiving portion 169B of the photoelectric detector 169 are provided opposite to each other via supports 167, 167 outside the both side plates of the chute 153, respectively. The optical axis of the fiber of the photoelectric detector 169 is set so as to pass through the hole (not shown) of the side plate and to pass in parallel above the central portion of the open / close door 161 in the closed state at a position approximately at the middle height of the thickness of the welding ring Wf, While the fiber light is incident on the light receiving section 169B, the opening / closing door 161 is closed,
The opening / closing door 161 opens when the light is blocked for a predetermined time or more. Therefore, a short interruption of the fiber light in which the welding ring smoothly sliding on the bottom plate 153a blocks light is ignored.

A storage box 171 for recovering a welding ring Wf having a poor inside diameter is provided directly below the shutter 157 on the bolster surface 1b, and a thickness defect is provided immediately below the opening / closing door 161 on a shelf 172 fixed to the side surface of the frame 1. A storage box 173 for collecting the welding ring Wf is installed.
A product storage box (not shown) for storing a non-defective welding ring Wf is provided immediately below the four terminal portions.

On the other hand, a push rod 174 is fixed downward at a position corresponding to the seventh station g of the ram 4, and the welding ring Wf gripped by the gripping claws 66A, 66B of the table jig 56 slides on the guide plate 131. When the ram 4 is conveyed to the seventh station g and positioned at the start end of the chute 153, the pushing rod 174 is lowered by the lowering of the ram 4, and the welding ring Wf held by the holding claws 66A and 66B is pushed down onto the chute 153.

At this time, whether the inner diameter of the dropped welding ring Wf is good or defective is stored in the NC device. In the case of a good product, the shutter 157 is closed and the dropped good welding ring is closed. Wf slides down. Also,
In the case of a defective welding ring Wf, the air cylinder 158 is used.
As a result, the shifter 157 is opened and the defective welding ring Wf is discharged to the defective product storage box 171.

Thus, the bottom plate 153a of the chute 153
The opening / closing door 1 in which the welding ring Wf sliding down is closed.
When sliding to the upper surface 161a of the gate 61, the gate rod 166
Will pass under. Here, when the thickness of the welding ring Wf is larger than the allowable maximum value due to, for example, stagger of the butt weld portion, poor crushing of the weld bead, distortion of the upper and lower surfaces, etc., the gap between the gate rod 166 and the upper surface 161a of the opening / closing door. Can not pass through the gap, and stops. When the stopped welding ring Wf interrupts the fiber light and the fiber light does not enter the light receiving portion 169B of the photoelectric detector 169 and a certain time has elapsed, the opening / closing door 161 is opened by the air cylinder 162.
Is opened, and the welding ring Wf having the insufficient thickness is discharged to the storage box 173. And the welding ring W which passed the thickness inspection safely
f is discharged to a product storage box (not shown) through the auxiliary chute 154.

The mechanism of each station a to g and the operation thereof have been described above. The operation of the burr-free welding ring device of the present invention will be described from the first station a to the seventh station g. I do.

The wire Wa supplied from a wire feeder (not shown) installed outside the machine is intermittently sent out to the coiling mechanism 31 by the feed rollers 27A and 27B of the wire feeder 26 to the coiling mechanism 31. The wire Wa, which is coiled by the individual forming rollers 33 and 34 and has a semicircular coiling formed portion at the tip end shown in FIG. 17A, is further wound by one turn as shown in FIG. 7B. Thus, an annular ring Wb for 1.5 turns is obtained.

When the coiling is completed, pressurized air is supplied to the upper chamber of the air cylinder 71 and the piston rod 72 descends, and the outer periphery of the annular ring Wb is gripped by the gripping claws 66A and 66B of the table jig 56 by the force of the spring 67. I do. Then, after the ram 4 is lowered, the die set upper base 45 of the cutting die set 42 is lowered, and the upper surface of the annular ring Wb is pressed against the upper surface of the cutting die 47 by the force of the spring 50 with the work holding plate 51.
As shown in FIG.
As shown in (c), the annular ring Wb for one turn is connected to the wire Wa.
At the same time, chamfers Wc and Wc are formed at the inner and outer corners of the annular ring Wb.

When the cutting is completed, the ram 4, the die set upper base 4
5, the pressure air is supplied to the lower chamber of the air cylinder 71, the piston rod 72 rises, the table jig 56 moves to the upper limit position by the force of the spring 62, and
A, the annular ring Wb gripped by 66B rises, and the index ring 18 is rotated at 45 ° each time, passes through the second station b and the third station c, and is cut into the fourth station d. Wb is indexed and positioned.

When the annular ring Wb is positioned at the fourth station d, the upper slide 81 of the welding mechanism 76 is lowered by the lowering of the ram 4 to fix the cut end of the annular ring Wb near one of the opposed end surfaces Wd. Spring 85 on top of electrode 89
Is pressed and held by the pressing claw 93 by the force of.

Next, the pressurized air is supplied to the upper chamber of the air cylinder 99 and the other upper slide 97 descends, and the pressing claw 109 near the other cut end face Wd of the annular ring Wb on the upper surface of the moving electrode 106. After holding the upper and lower surfaces flush with each other, pressurized air is supplied to the rear chamber of the air cylinder 112 (the chamber on the side opposite to the movable stand 95) to move the movable stand 95 to the fixed stand 78 side.

With this movement, the other facing end face Wd is pressed against one facing end face Wd, and the fixed electrode 89 and the moving electrode 106 are pressed.
A voltage is applied during the butt welding. The butt-welded welding ring Wf is an annular ring Wb.
The weld bead We is distorted from the circular shape to the elliptical shape and is raised on the inner and outer circumferences as shown in FIG. 17D. The weld bead We is formed in the V-shaped concave portion (groove) formed by the chamfered portions Wc and Wc. The weld bead We that is settled and raised on both the upper and lower surfaces is in a protruding state.

The electrodes 89 and 106 are connected to the insulating pad 8
7, 104, the pressing claws 93, 109 are insulated from the main body.
Are insulated from the main body by insulating pads 91 and 107, and the gripping claws 66A and 66B of the table jig 56 are coated with an insulating material on the work contact surface 66a and insulated from the main body. Does not leak to the main body.

Further, both electrodes 89 and 106 and both pressing claws 9
3, 109 are electrode bases 88, 105 and nail bases 92,
Since 108 is cooled by cooling water, the temperature rise due to welding heat is small.

When the butt welding is completed, pressurized air is supplied to the lower chamber of the air cylinder 99 and the other upper slide 9
7, the pressing claw 109 separates from the welding ring Wf,
Simultaneously, after the ram 4 is raised and the pressing claw 93 is separated from the welding ring ring Wf, pressurized air is supplied to the front chamber (chamber on the moving stand 95 side) of the air cylinder 112 to move the moving stand 95 to the side opposite to the fixed stand 78. Retreat to and wait.

Next, the index table 18 stores 45
The welding ring Wf that has been turned and welded is indexed to the fifth station e. The welding ring Wf indexed to the fifth station e is positioned concentrically with the hole 126a of the forming die 126 and slightly above the upper end surface 126c of the forming die 126. The welding ring Wf is extruded from the holding claws 66A and 66B, and is pushed into the hole 126a of the forming die 126. Hole 12
The inner diameter of 6a is formed to be the same as the outer diameter of the completed welding ring Wf and has a chamfered portion 126b at the entrance, so that the welding ring Wf distorted into an elliptical shape by butt welding is fitted. Is formed into a perfect circular shape by this fitting.

When the welding ring Wf is inserted into the hole 126a, the upper end surface 126c of the forming die 126 and the upper end surface 127a
Knockout punch 1 with the same height
27 is pushed down against the force of the spring 129, and the lower end surface 127b is positioned in contact with the bolster surface 1b.
As a result, the weld bead We, which is pressed between the lower end surface 125a of the pressing punch 125 and the upper end surface 127a of the knockout punch 127 and protrudes from the upper and lower surfaces of the welding ring Wf, is crushed.

Next, when the ram 4 is raised, the pressing punch 125
Rises, the force of the spring 129 causes the knockout punch 12
7 rises to form the welding ring Wf into the hole 12 of the forming die 126.
Pressing from 6a, the pressing punch 125 separates from the welding ring. The welding ring Wf extruded from the hole 126a is gripped by the holding claws 66A and 66B in a standby state. However, unlike the holding state from the first station a to the fifth station e, the welding ring Wf is near the mouth of the holding claws 66A and 66B. In a shallow gripping state, the subsequent welding ring Wf is transported by indexing the index table 18 on a guide plate 131 having the same height as the upper surface 126c of the forming die 126.

When the welding ring Wf after the face pressing is indexed to the sixth station f, the welding ring Wf is concentric with the hole 131a formed in the guide plate 131, and the gripping claws 66A, 66B
While the ram 4 is lowered, the inspection mechanism 13
5 is lowered, and the lower end of the stripper 141 is welded to the welding ring Wf.
And presses the welding ring Wf onto the guide plate 131 by the force of the spring 142.

At this time, if the inner diameter of the welding ring Wf is within the allowable error range, the plug gauge 13
9 is inserted into the hole of the welding ring Wf, and stops at the step end face with the following step 139b. In this state, the outer peripheral groove 143a of the slit collar 143 matches the fiber light X of the photoelectric detector 146, the fiber light emitted from the light emitting unit 146A enters the light receiving unit 146B, and the detection signal is sent to the NC device. It is memorized.

When the inner diameter of the welding ring Wf is out of the permissible error range, the tip 139a of the plug gauge 139 cannot be inserted or the second step 139b.
, And no fiber light enters the light receiving section 146B, and is stored as a defective product in the NC device. Next, after the inspection mechanism 135 is lifted by the raising of the ram 4 and separated from the welding ring Wf, the table jig 56 turns by 45 ° and the welding ring Wf slides on the guide plate 131 and moves to the seventh station.

The welding ring Wf indexed to the seventh station g is positioned above the starting end of the inclined chute 153, and when the ram 4 is lowered, the welding ring Wf is moved from the gripping claws 66A and 66B by the push rod 174. It is pushed out and falls on the shutter 157 on the same plane as the upper surface of the bottom surface 153a of the chute 153. If the dropped welding ring Wf is determined to be non-defective at the sixth station e, the shutter 157 is closed and the bottom plate 15
3a and slide down. If it is determined that the product is defective, pressurized air is supplied to the front chamber (piston rod side chamber) of the air cylinder 158, the shutter 157 is opened, and the product is discharged into the storage box 171 for defective products.

When the welding ring Wf passing through the shutter device 155 provided at the start end and sliding down on the bottom surface 153a of the chute 153 comes close to the end, only the welding ring having a thickness equal to or larger than the allowable maximum value becomes the gate rod. 166 abuts and stops. Then, the light emitting unit 1 of the photoelectric detector 169
The fiber light emitted from 69A is interrupted by the stopped welding ring Wf and does not enter the light receiving section 169B. When this state continues, pressurized air is supplied to the rear chamber (chamber on the side opposite to the piston rod) of the air cylinder 162, the opening / closing door 161 opens, and the welding ring Wf having a poor thickness is placed in the storage box 17 for the defective product.
3 is discharged. Then, the welding ring Wf that has passed safely below the gate rod 166 is discharged through an auxiliary chute 154 to a product storage box (not shown).

In the above, the work (ring) gripped by one of the eight table jigs 56 provided on the outer peripheral portion of the index table 18 is sequentially indexed and processed at each station. I explained,
Actually, the works indexed to each station at the same time are processed simultaneously.
One rotation of 8 enables continuous production of 8 welding rings.

[0082]

The method and apparatus for manufacturing a burr-free welding ring according to the present invention have the following advantages because they are constructed as described above. While the work transfer mechanism makes one rotation, a wire having a rectangular cross section is coiled into an annular body, and at the same time as cutting, the inner and outer corners of the cut surface are chamfered, and the opposed cut surfaces of the annular body are brought into contact. Weld so that the weld bead does not protrude on the inner and outer circumferences, press the welded elliptical weld ring into the hole of the forming die by pressing it with a pressing punch, form it into a perfect circular shape, and place it on the knockout punch. The welding bead projecting from the upper and lower surfaces of the welding ring between the end face and the lower end face of the pressing punch is crushed to make it the same plane, and the product is inspected and discharged. Improvements and reductions in manufacturing costs are possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the entire burr-free welding ring manufacturing apparatus as viewed from above, and is a cross-sectional view taken along line BB of FIG.

FIG. 2 is a front sectional view showing the entire burr-free welding ring manufacturing apparatus, and is a sectional view taken along line AA of FIG.

3 is a cross-sectional view as viewed from above, showing the coiling mechanism and the cut-away cross-sectional mechanism, and is a cross-sectional view taken along the line EE in FIG. 4;

FIG. 4 is a sectional view taken along the line CC of FIG. 3;

FIG. 5 is a vertical sectional view of the cutting mechanism, taken along the line DD in FIG. 3;

6 is a front sectional view of the cutting mechanism, taken along line HH of FIG. 3;
It is arrow sectional drawing.

7A is a sectional view taken along the line FF of FIG. 6, and FIG.
FIG. 7 is a sectional view taken along line GG of FIG. 6.

FIG. 8 is an explanatory diagram of a work holding portion of the table jig;
(A) is a sectional view taken along the line SS in (b), (b) is a front view, and (c) is a sectional view taken along the line TT in (b).

FIG. 9 (a) is a vertical sectional view of the welding mechanism shown in FIGS. 1 and 1;
0 is a cross-sectional view taken along the line MM, (b) is a cross-sectional view taken along the line PP of (a), and (c) is a diagram viewed from the Q direction of (a).

FIG. 10 is a cross-sectional view of the welding mechanism as viewed from above,
FIG. 4 is a cross-sectional view as viewed from the direction of the arrow N.

11 is a vertical sectional view showing a state before the surface pushing of the surface pushing mechanism, and is a sectional view taken along line JJ of FIG. 1;

12 is a vertical cross-sectional view of the surface pressing mechanism showing a state during the surface pressing, and is a cross-sectional view taken along line JJ of FIG. 1;

13A is a vertical sectional view of the inspection mechanism, and FIG.
FIG. 2B is a cross-sectional view taken along the arrow H, and FIG.

14 (a) to (c) are enlarged views of a portion L surrounded by a virtual circle in FIG. 13, and are operation explanatory diagrams showing a state of inspection of a non-defective / defective product by an inspection mechanism, and (a) is an excessively large inner diameter. The figure which shows the state which detected the defective article, (b) The figure which shows the state which detected the good article,
(C) is a diagram showing a state in which a defective product with an insufficient inner diameter is detected. (D) is an enlarged view of the stopper gauge.

FIG. 15 is a top view of the work discharge mechanism.

FIG. 16 is a front view of the work discharge mechanism, as viewed from the direction of the arrow R in FIGS. 1 and 15;

FIG. 17 is an explanatory view showing the shape of each processing step of the work,
(A) shows a state before coiling, (b) shows a state after coiling, (c) shows a state after cutting and chamfering, and (d) shows a state after welding. ,
(E) is a diagram showing a state where a perfect circular shape molding and surface pressing are performed, and (f) is a diagram showing a state at the time of an inner diameter inspection.

FIG. 18 is an explanatory view of a conventional grooved ring polishing apparatus of the related art.

[Explanation of symbols]

 Reference Signs List 1 frame 2 bearing housing 3 guide post 4 ram 5 cam shaft 6 eccentric cam 8 indexing unit 16 upper beam 17 lower beam 18 index table 24, 25 cam follower 26 wire feeder 27A, 27B feed roller 28 servo motor 29A, 29B straightener Reference Signs List 30 quill 31 coiling mechanism 32 core metal roller 33, 34 forming roller 35, 57 substrate 40 cutting mechanism 42 cutting die set 43 die set lower stand 45 die set upper stand 47 cutting die 48 punch holder 49 cutting punch 50 spring 51 work holding plate 56 Table jig 58 Upper plate 59 Lower plate 64A, 64B Holding arm 66A, 66B Gripping claw 69 Cross beam 71, 99, 112, 158, 162 Air cylinder 76 Welding mechanism 77 Base 78 Fixed stand 81, 7 Upper slide 83 Spring core 85, 142 Spring 86 Fixing base 87, 91, 104, 107 Insulating pad 88, 105 Electrode base 89 Fixed electrode 92, 108 Claw base 93, 109 Pressing claw 95 Moving stand 111 Stand 124 Surface pressing mechanism 125 Press Punch 126 Forming Die 127 Knockout Punch 131 Guide Plate 135 Inspection Mechanism 137 Inspection Axis 138 Spring 139 Plug Gauge 141 Stripper 143 Slit Collar 146,169 Photodetector 146A Light Emitting Part 146B Light Receiving Part 150 Work Ejection Mechanism 153 Shooting Chute Shutter device 157 Shutter 159 Door device 161 Opening / closing door 166 Gate rod 171,173 Storage box 174 Push rod

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21F 37/00 B23K 37/08

Claims (4)

(57) [Claims] 1. A wire having a square cross section is brought into contact with a molding member to form a coil by coiling, and then the end of the ring is cut by a cutting punch and a cutting die having a drum-shaped cross section. By separating the wire from the wire and chamfering the inner and outer corners of the cut surface, the upper and lower surfaces of the opposed cut surface of the annular body are brought into contact on the same plane, and the inner and outer peripheries of the contact portion are formed by the chamfer. The annular body is butt-welded so that the weld bead does not protrude from the V-shaped recess to be formed into a weld ring, and the weld ring is pressed into a hole having the same outer diameter as the outer diameter of the forming die when the weld ring is completed. And press the upper and lower surfaces of the welding ring between the upper end surface of the knockout punch and the lower end surface of the pressing punch in the hole of the forming die to press the upper and lower surfaces. A method for manufacturing a burr-free welding ring, comprising crushing a weld bead projecting from a surface to flatten the upper and lower surfaces. 2. A device for manufacturing a burr-free welding ring from a wire having a square cross section, comprising: a coiling mechanism for abutting a straight wire fed from a quill on a forming member to form a ring-shaped body; An end portion of the annular body comprising a vertically movable cutting punch formed in a drum shape having a chamfered slope and a cutting die having a drum-shaped hole into which a tip of the cutting punch can be fitted. A cutting mechanism that cuts the inner and outer peripheral corners of the cut surface by the slope and the upper and lower surfaces of the cut surface opposite to the cut annular body are brought into contact on the same plane, and the inner and outer peripheries of the contact portion are cut off. A welding mechanism that butt-welds the annular body to form a welding ring so that the welding bead does not project from the recess formed by the chamfer, and a hole having the same dimensions as the outer diameter of the completed welding ring. A die, a knockout punch which is vertically movably inserted into a hole of the forming die, and whose upper end surface can be positioned at a position where the welding ring is pressed in the forming die and a position where the welding ring is pushed out of the forming die, respectively; A press punch which is vertically opposed to the knockout punch and whose tip end is inserted into the hole of the forming die. The press punch presses the welding ring to fit into the hole of the forming die. A surface pressing mechanism that is formed into a shape and presses the welding ring with the pressing punch and the knockout punch to crush a welding bead projecting up and down to a flat surface without burrs, and a position where each of the mechanisms is disposed. An apparatus for manufacturing a burr-free welding ring, comprising: a work transfer mechanism for positioning a work. 3. The apparatus according to claim 2, wherein the forming member of the coiling mechanism is a plurality of rotatable forming rollers. 4. The upper and lower portions formed after the face pushing mechanism, in the order of a side plug gauge portion having a tip portion having the same dimension as the allowable minimum inner diameter of the welding ring, and a stop side plug gauge portion having the same size as the allowable maximum inner diameter. An inspection mechanism comprising a movable plug gauge member and a detecting means for detecting the quality of the inner diameter based on the vertical position of the plug gauge member, wherein the inner diameter of the welding ring is inspected. 4. The apparatus for manufacturing a burr-free welding ring according to 2 or 3.