JPH06238461A - Spot welding equipment for nut - Google Patents

Abstract

PURPOSE:To provide a spot welding equipment for a nut where the setting time of the nut for a work is short, productivity is high and the deviation of the nut is not caused. CONSTITUTION:This is the spot welding equipment of the nut where the work 10 is mounted horizontally on the upper surface of a lower electrode 30, the nut 20 is mounted on the work 10, and upper electrode 40 is lowered from above, the work 10 and the nut 20 are held between the upper and lower electrodes 30 and 40, a current is passed, heat is generated on the contact surface between the work 10 and the nut 20, these are welded together, a hole 11 of the work 10 and the nut 20 are superposed on each other on the upper surface of the lower electrode 30, a guide pin 31 passing through these is provided projectingly and plural lugs are provided projectingly in the vicinity of the bottom of the nut 20. The nut seat 63 to mount the nut 20 which is held in the almost horizontal direction by kick springs 62 under normal conditions and rotates below vertically when pushed down by the upper electrode 40 to fall at the faster speed than the natural falling speed of the nut 20 is supported pivotally on the tip of a piston rod to move in the horizontal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding device for continuously spot welding a nut to a plate-shaped work.

[0002]

2. Description of the Related Art A description will be given with reference to FIG. The spot welding of the nut set according to the bolt hole formed in the work is usually performed by the following apparatus and operation.
That is, the work 10 is placed horizontally on the upper surface of the lower electrode 30, the nut 20 is placed on the work 10, the upper electrode 40 is lowered from above, and the work 10 and the nut 20 are sandwiched between the upper and lower electrodes 30, 40. At this point, an electric current is applied to heat the contact surfaces of the two and weld them. More specifically, a guide pin 31 is provided on the upper surface of the lower electrode 30 so that the hole 11 of the work 10 and the nut 20 are overlapped with each other and passed through. A plurality of ears 21 are provided on the lower surface of the nut 20 and around the nut 20. Then, the nut 20 is attached to the work 10.
When setting it on the hole 11 of the above, the nut 10 which has been previously filled in the rail 90 so that it can be taken out from below is temporarily received on the slide 95, and is extruded sequentially from the lowermost nut 20 by the piston rod 50 moving forward and backward in the slide 95. The position and the posture of the nut 20 are controlled by using the attraction force to the magnet 59 attached to the tip of the piston rod 50 while being carried to the hole 11 of the work 10.

However, in the conventional nut spot welding apparatus, the upper electrode 40 can be lowered until the piston rod 51 lowers the nut 20 onto the work 10 and sets and then retracts the nut 20. However, there is a problem that it takes time to set the nut 20, the speed is low, the productivity is low, the stability is poor, and the nut 20 is easily displaced.

[0004]

The problems to be solved by the invention are that, in the above-mentioned conventional nut spot welding method and apparatus, it takes time to set the nut 20, the speed is low, the productivity is low, and It is lacking in stability and the shift of the nut 20 is likely to occur.

[0005]

Means for Solving the Problems An explanation will be given with reference to FIGS. The present invention includes a lower electrode 30 and an upper electrode 40.
Means for transferring the nut 20 between and the transferred nut 2
0 toward the screw hole 22 and the guide pin 3 of the upper electrode 40 at a speed faster than the natural falling speed of the nut 20 due to gravity.
And a means for bringing the nut (20) into contact with a predetermined portion of the work 10 placed on the lower electrode 30 by suddenly lowering the work piece 1.

A detailed description will be given. The work 10 is placed horizontally on the upper surface of the lower electrode 30, and the nut 2 is placed on the work 10.
0 is placed, the upper electrode 40 is lowered from above, the work 10 and the nut 20 are sandwiched between the upper and lower electrodes 30 and 40, and a current is applied to heat the contact surfaces of the work 10 and the nut 20 to cause welding. Of the lower electrode 30, the hole 11 of the work 10 and the nut 20 are superposed on each other, and a guide pin 31 is provided so as to pass therethrough, and a plurality of ears 21 are provided so as to project on the lower surface of the nut 20. Spot welding apparatus for a piston rod 50 that moves back and forth in the horizontal direction
At the tip of the nut 20, the kick springs 62 and 62 normally hold the nut 20 in a substantially horizontal direction, and when the nut 20 is pushed down by the upper electrode 40 that descends at a speed faster than the natural falling speed of the nut 20, the nut 20 rotates vertically downward. The nut seat 63 on which the is mounted is pivotally supported.

[0007]

EXAMPLE An example will be described. Reference numeral 10 is a plate-shaped work having a hole 11. Reference numeral 20 denotes a nut which is coaxially mounted on the hole 11 of the work 10 and spot-welded, and a plurality of ears 21 are provided on the lower surface and the periphery thereof so as to project. Reference numeral 30 denotes a lower electrode on which the work 10 is placed, and a guide pin 31 through which the hole 11 and the nut 20 of the work 10 are overlapped with each other is projected on the upper surface thereof. Reference numeral 40 denotes an upper electrode which is provided directly above the lower electrode 30 so as to be movable up and down, and an upper surface of the upper electrode is supported by a compression spring 42 and a guide pin 41 to be inserted into the nut 20 is projected at the tip thereof. Reference numeral 43 is a set bolt that supports the compression spring 42.

Next, reference numeral 50 is a piston rod which is driven by an air cylinder 51 to move forward and backward in a horizontal direction with respect to both electrodes 30 and 40, and 52 is a rectangular parallelepiped tip block attached to the tip of the piston rod. Wing portions 53, 53 are provided on the ridge. Incidentally, 54 and 54 are air ports provided in the air cylinder 51, and 54 and 54 are proximity switches. Reference numeral 60 denotes a rocker that pivotally supports arm pieces 61, 61 so as to sandwich the front block on the side surface front portion of the tip block 52.
It is integrally connected to a nut seat 63 on which the load is mounted, and is normally held in a substantially horizontal direction by the kick springs 62, 62, but when pushed down by the upper electrode 40, it rotates vertically downward. At the center of the upper surface of the nut seat 63, the nut 2
A protrusion 64 into which 0 is fitted is provided. Also, the oscillator 60
Has its front portion widened in the vertical direction to form a cam 65 (details will be described later).

Further, reference numeral 70 denotes a lower slide which extends forward from the lower part of the front surface of the air cylinder 51, 71 denotes an inclined portion formed by inclining a front upper surface thereof downward, 72,
72 is a support pillar, which is erected on both sides immediately behind it, 73, 7
The reference numeral 3 designates spring seats projecting from both sides of the rear part of the lower slide 70.
I am running forward between No. 2 and 72. Reference numeral 80 denotes an upper slide that rotatably supports the middle portions of the side surfaces of the supporting columns 72, 72 so as to face the upper side of the lower slide 70. There is. 82,8
2 is an inclined portion formed by inclining the front lower side upward, 83 is a nut holding plate extending forward at the front end of the upper surface of the upper slide 80, and 84 is hung vertically from the upper front portion of the upper slide 80. The guide wall is provided with a notch (not shown) through which the nut 20 can pass. Reference numeral 85 is a stopper block attached to the upper rear portion inside the upper slide 80, and the lower surface of the front portion is inclined upward.

The spring seats 73 and the upper slide 8 are arranged.
When an upper slide support spring 74 is interposed between the rear lower surface of 0 and the rear end of the piston rod 50, first, the cams 86, 86 at the rear corners of the inclined portions 82, 82 of the upper slide 80 are moved to the tip block 52. Riding on the wing portions 53, 53 of the upper slide 80, the front portion of the upper slide 80 rotates upward around the support shaft against the support spring 74. Further, when the front cam 65 of the rocker 60 rides on the rear corner of the inclined portion 71 of the lower slide 70, the front part of the rocker 60 is lifted. In addition, the lower end of the rail 40 for filling the nut 20 is connected and opened at the front part of the upper surface of the upper slide 80, and the nut 20 can be sequentially pushed out by sending air from above. Reference numeral 91 is a tube connected to the upper end of the rail 90.

The operation will be described with reference to the drawings. As shown in FIG. 1, the piston rod 50 is advanced to the most advanced position so that the nut 20 placed on the nut seat 63 comes directly under the upper electrode 40. At this position, when the upper electrode 40 is suddenly dropped at a speed faster than the natural falling speed of the nut 20,
The nut 20 on the nut seat 63 is fitted into the guide pin 41 of the upper electrode 40, and the nut seat 63 is pushed down against the kick springs 62, 62 with the hinge shaft as the pivot shaft, resulting in the state of FIG. It can be retracted by the cylinder 51. The nut 20 is the upper electrode 4
In the state of being fitted in the guide pin 41 of 0, it is pushed down at a speed higher than its natural falling speed, is pressed against the work 10, and the nut 20 is fitted in the guide pin 31 of the lower electrode 30 (of the upper electrode 40). The guide pin 41 is pushed up by the guide pin 31 and retreats). Both electrodes 3 in this state
When a current is applied between 0 and 40 to heat the contact surface between the work 10 and the nut 20, the nut 20 is spot-welded to the work 10.

Next, as shown in FIG. 3, while rubbing the lowermost nut 20 in the rail 90, the piston rod 50
Retreat, the cam followers 86, 86 of the upper slide 80 ride on the wings 53, 53, and the front portion of the upper slide 80 resists the support spring 74 and rotates upward about the bearing shaft,
The posture of the nut 20 should be more horizontal. 6 arm pieces
When the rear end portions of the rollers 1, 61 pass below the cam follower 86, and the cam 65 of the rocker 60 rides on the upper surface from the inclined portion 71 of the lower slide 70, the rocker 60 moves around the fulcrum. As shown in FIG. 4, the nut 2 is rotated upward and the lower end edge of the screw hole of the nut 20 is pushed by the protrusion 64, and the front portion of the stopper block 85 of the upper slide 80 is used as a fulcrum.
4 is rotated clockwise in the plane of FIG. 4, and the nut 20 is fitted into the protrusion 64 with the ear 21 facing down as shown in FIG. After this, together with the piston rod 50, the nut seat 6
3, the nut 20 is placed, the rocker 60 moves forward, returns to the state of FIG. 1, and the above operation is repeated. In addition,
During this time, the upper electrode 40 has already completed spot welding and has returned to the state of FIG.

[0013]

Since the present invention is constructed as described above,
When the piston rod 51 is in the most advanced state, the upper electrode 40 can be lowered without being disturbed by it, and the nut 2
0 can be transferred from the nut seat 63 to the lower surface of the upper electrode 40, lowered at a speed higher than the speed of the natural fall of the nut 20, and pressed against a predetermined position of the work 20, so that the setting time of the nut 20 is significantly shortened. This greatly increases the speed of spot welding. Others, nut 20 rail 9
The work piece 10 can be accurately moved to a predetermined position from 0 through the nut 63, and the deviation of the nut 20 seen in the conventional beam can be completely prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a conventional example.

FIG. 2 is a side view showing an embodiment of the present invention.

FIG. 3 is a side view showing a state in which the piston rod according to the embodiment of the present invention is advanced to the most distal end.

FIG. 4 is a side view showing a state in which an upper electrode is lowered in FIG.

FIG. 5 is a side view showing a state in which a nut is set on the lower electrode.

FIG. 6 is a side view showing a state in which the piston rod is retracted.

FIG. 7 is a side view showing a state in which the piston rod is retracted to the rearmost end and the nut is moved to the nut seat.

8 is a cross-sectional view taken along the line AA of FIG.

9 is a sectional view taken along line BB of FIG.

10 is a cross-sectional view taken along line CC of FIG.

FIG. 11 is a perspective view of a main part viewed from above.

FIG. 12 is a perspective view of another main part as viewed from above.

[Explanation of symbols]

 10 Work 11 Hole 20 Nut 21 Ear 22 Screw Hole 30 Lower Electrode 31 Guide Pin 40 Upper Electrode 41 Guide Pin 42 Compression Spring 43 Set Bolt 50 Piston Rod 51 Air Cylinder 52 Tip Block 53 Wing 54 Air Port 55 Proximity Switch 59 Magnet 60 Oscillator 61 Arm piece 62 Kick spring 63 Nut seat 64 Projector 65 Cam 70 Lower slide 71 Inclination part 72 Support column 73 Spring seat 74 Upper slide support spring 80 Upper slide 82 Inclined part 83 Nut pressing plate 84 Guide wall 85 Stopper block 86 Cam 90 Rail 91 Tube 95 Slide

Claims (2)

[Claims] 1. A means for transferring a nut (20) between a lower electrode (30) and an upper electrode (40), the nut (20) being moved toward a screw hole (22) of the transferred nut (20). The upper electrode (4
0) A spot welding apparatus for nuts, which is provided with means for causing the guide pin (31) of (0) to be suddenly lowered and fitted and for bringing the nut (20) into contact with a predetermined position of the work (10) placed on the lower electrode (30). . 2. The work (10) is placed horizontally on the upper surface of the lower electrode (30), and the nut (2) is placed on the work (10).
0) is placed, the upper electrode (40) is lowered from above, the work (10) and the nut (20) are sandwiched between the upper and lower electrodes (30, 40), and an electric current is applied to the work (10).
On the upper surface of the lower electrode (30) where the contact surface of the nut (20) is heated and welded, the hole (1) of the work (10) is
1) The nut and the nut (20) are superposed on each other, and a guide pin (31) through which the thread passes is projected, and a plurality of ears (21) are projected on the lower surface and the periphery of the nut (20). In the apparatus, the kick spring (62, 6) is usually attached to the tip of the piston rod (50) that moves back and forth in the horizontal direction.
2) is held in a substantially horizontal direction and is pushed down by the upper electrode (40) to rotate vertically downward (2)
(0) is mounted on a nut seat (63) which is pivotally supported to form a spot welding device for nuts.