JPH07171683A - Method and device for high speed feeding in automatic stud welding - Google Patents

Abstract

PURPOSE:To speedily and precisely feed a stud required to speed up a welding process speed of stud welding. CONSTITUTION:A stud is feeded to a second escape 6 placed near a welding gun 1 from a feeder 2 in high speed with increasing a pneumatic pressure ratio. Sucessively, stable feeding is executed from the second escape to the welding gun with decreasing a pneumatic pressure ratio. Further, while stud welding is executed, a next stud is feeded from a first escape 5 to the second escape to be waited. By this method, an overall feeding speed of stud is increased, shortening stud welding process time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention feeds studs at a higher speed and with higher accuracy, which is required to increase the welding process speed of stud welding in an automated line in the automobile and other industrial fields. The present invention relates to a high-speed stud supply method and apparatus for automatic stud welding.

[0002]

2. Description of the Related Art In the case of robot stud welding in an automated line for performing stud welding, for example, in an automobile body assembly line, a stud welding device is constituted by each device shown in FIG. It has a gun 1, a robot 4 for mounting it, a feeder 2 for supplying studs, a power supply device 3 for supplying welding current, and a control device for controlling these mutually, and the welding current is sent by a welding cable 10. The studs are pneumatically fed to the welding gun 1 by a feed tube 7. The robot is installed close to the line, and the feed tube for supplying studs is connected to the feeder 2 with a length of about 10 to 11 m. In the conventional case, the feed tube 7 shown by the dotted line in FIG.
Connected to. The stud is fed from the first escape 5 of the feeder 2 by compressed air through the feed tube 7 to the welding gun 1, and the chuck 11 of the welding gun 1 is fed.
After being gripped by the object to be welded, for example, the car body 1
2 is stud welded. Next, the robot 4 feeds the next stud S from the first escape 5 to the welding gun 1 while moving the welding gun 1 to the next welding position, and repeats the stud welding at the next welding position. Fig. 5 is a time chart of the welding process of conventional stud welding.
The state of feeding the stud S by the first escape 5 is shown in FIG. 5B. A ~ E in the time chart is B
Corresponds to A to D in the figure. As can be seen from the time chart, in the conventional stud feeding method by stud welding, the feeding time of a certain stud to the welding gun 1 is 1.
It takes 4 seconds and the total welding process time is 3.6 seconds.

Usually, the work piece 1 to which the stud is to be welded
2. In particular, since the car body has a complicated structure, the welding gun also approaches the welding position while performing a complicated operation, and requires a posture of 360 degrees such as downward, sideways, or upward.

[0003]

For this reason, the feed tube 7 must follow this, and it may be wrapped around the arm of the robot 4. Feed tube 7
Is not in a constant state, but is constantly changing,
Since the air resistance and contact resistance inside the feed tube are changing, the state of the studs passing through them is not constant. Therefore, empirically, the compressed air pressure for sending out from the first escape 5 is set according to the shape and size of the stud, and a certain stud has an air pressure of 2 to 3 kilograms per square centimeter. However, this is not complete, and depending on the state of the feed tube 7, the feeding speed may be too fast, the stud may pop out of the welding gun 1, or the feeding speed may be too slow to reach the welding gun. In order to shorten the welding process time and increase the production speed, as shown in the time chart of FIG.
It is necessary to shorten the stud feeding time. Therefore, when the compressed air pressure is increased to feed the stud, the stud pops out of the welding gun, making it difficult to shorten the time with the conventional method.

According to the present invention, when the stud is fed, the stud is not fed directly from the feeder to the welding gun, but the stud is fed at a high speed up to the second escape near the welding gun and then fed to the welding gun. By doing so, the distance to the welding gun can be reduced, stable and reliable stud feeding can be achieved, and the welding process time can be shortened.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and sends a stud at high speed by increasing compressed air pressure to a second escape arranged near the welding gun from a feeder. Feeding, then reducing the compressed air pressure from the 2nd escape to the welding gun for stable feeding, and feeding the next stud from the 1st escape to the 2nd escape while performing stud welding. The gist of the invention is to increase the feeding speed of the stud and shorten the stud welding process time by supplying and waiting the stud.

[0006]

[Operation] The compressed air pressure is increased from the feeder to the second escape arranged near the welding gun to feed the stud at high speed, and then the compressed air pressure is reduced from the second escape to the welding gun to ensure stable feeding. In addition to doing so, while the stud welding is being performed, the next stud is fed from the first escape to the second escape and kept waiting to increase the stud feeding speed overall. The welding process time can be shortened.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-speed stud supply method and apparatus for automatic stud welding according to the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a layout drawing of each device in an automatic stud welding apparatus according to an embodiment of the present invention, in which a stud welding gun 1 for direct welding (feed tube 7 shown by a dotted line in the drawing shows a conventional method), The robot 4 is equipped with a stud, a feeder 2 for supplying studs, a power supply device 3 for supplying a welding current, and a control device for mutually controlling these. The welding current is supplied from the power supply device 3 to the welding cable 10.
Flowed into the welding gun 1 by means of a feeder 2 through a first escape 5 through a feed tube 8 to a second escape 6 and then a feed tube 9
And is pneumatically fed to the welding gun 1.

The second escape 6 is mounted on the robot 4, the second escape 6 is connected to the first escape 5 of the feeder 2 by the feed tube 8, and the feed tube 9 is connected to the robot by the second escape 6. 4 is connected to a welding gun 1 arranged at the tip of the nozzle 4. Therefore, the feed tube 8 connecting the first escape 5 and the second escape 6 is long, and the second escape 6 and the robot 4 are connected.
The feed tube 9 connected to the welding gun 1 arranged at the tip of the is short.

The second escape 6 mounted on the robot 4
6, the transfer bar 61 is slidably inserted into the main body 60, and the transfer bar 61 is connected via the piston rod 63 of the composite air cylinder 62 joined to the main body 60 to connect the composite air cylinder 62. The transfer bar 61 is slidable for a predetermined stroke, and a tube connection port 64 for joining the feed tube 8 to the main body 60 and a pressure air supply port 65 for supplying pressure-feeding air at a predetermined pressure are provided. Further, a cushion 66 is provided at a position facing the tube connection port 64.
Further, a tube connection port 67 for joining the feed tube 9 is provided at a position facing the compressed air supply port 65.

The second escape 6 slides the transfer bar 61 between both end positions where the piston rod 63 of the compound air cylinder 62 appears and retracts, and at the protruding position, the stud through hole 6 penetrates into the transfer bar 61.
H and the tube connection port 67 that joins the pressure air supply port 65 and the feed tube 9 are aligned,
Further, in the retracted position, the tube connection port 64 for joining the feed tube 8 and the stud through hole 6H and the cushion 66 in the transfer bar 61 are arranged so as to be aligned with each other, and the piston rod of the composite air cylinder 62 is arranged. In the case of stopping at an intermediate position between the both ends where 63 appears and disappears, the stroke of the stud through hole 6H in the transfer bar 61 is determined so that both ends are closed by the main body as shown in FIG. 3B. .

The air pressure supplied from the first escape 5 of the feeder 2 to the feed tube 8 for stud passage is greater than the air pressure supplied from the second escape 6 to the welding gun 1 via the feed tube 9 for stud passage. Shall be high.

The first escape 5 attached to the feeder 2 is almost the same as the second escape 6, but the operation of the compound air cylinder is made possible to stop the transfer bar at two positions between both end positions of a predetermined stroke. It is made to slide, and a conventionally used one is adopted.

Therefore, in the device constructed as described above,
When feeding the stud S, first, when the stud S is supplied from the feeder 2 to the first escape 5, the stud S is supplied to the first escape 5 at a high speed with the relatively high pressure air.
The stud feed hole 6 of the transfer bar in the second escape 6 in the position of FIG. 3A is fed to the escape 6.
You can stop at H. At this time, the stud comes into contact with the cushion 66 to absorb the feed inertia due to the high air pressure,
When stationary within the stud through hole 6H, the transfer bar 61 moves by one pitch of the composite air cylinder 62.
Moves forward, stops at the intermediate position shown in FIG. 3B, and waits.

Immediately after the previously fed stud is welded, the next stud is fed to the welding gun 1 for the next welding. This is because the transfer bar 61 is moved forward from the intermediate position shown in FIG. 3B to the protruding position shown in FIG. When air is supplied, the stud that has been stationary in the stud through hole 6H is fed into the feed tube 9 to the welding gun 1 at a speed lower than the feed speed in the feed tube 8.

The length of the feed tube 8 up to the first escape 5 is usually about 10 m or more, and the length of the feed tube 9 from the second escape 6 to the welding gun 1 is about 2 m or less. The compressed air pressure for feeding from the escape 5 to the second escape 6 is set to about 4 to 5 kilograms per square centimeter, and the feeding speed is increased to shorten the feeding time.

Next, the compressed air pressure for feeding from the second escape 6 to the welding gun 1 is set to about 2 to 3 kilograms per square centimeter or less, and the air pressure is set so that the feeding to the welding gun 1 is stable and reliable. ing.

FIG. 3A shows a state in which the pistons of the compound air cylinder are all retracted, and the stud S fed from the feed tube 8 is stored therein. The stud S arrives at a high speed here. In this case, a cushion 66 is provided to prevent the stud from being damaged by an impact and the escape chamber from being damaged. FIG. 3B shows the state where the transfer bar 61 is moving to the intermediate point by the piston of the compound air cylinder being operated, because the stud S fed through the feed tube 8 is fed at high speed. Since it is vibrating, it is temporarily stopped at this intermediate point in order to stabilize it.

Next, FIG. 3C shows a state in which the transfer bar is moving to the receiving port of the feed tube 9 by the operation of the composite air cylinder, and the stud S is at the position to be fed into the feed tube 9 and the compressed air supply port is present. If compressed air is supplied from 65, the stud will be fed to the welding gun 1 through the feed tube 9. When the feeding is completed, the stud S fed through the composite air cylinder is accepted again.

Therefore, since the feed tube 9 from the second escape 6 to the welding gun 1 is about 2 m or less and thus has a short distance, the compressed air pressure is low and the feeding is stable.

FIG. 4A is a time chart showing the operation process of studs and welding which are fed to the welding gun from the first escape 5 to the second escape, and FIG. 4B is the operation sequence of the second escape. As shown in FIG. 4A, although the length of the feed tube 8 from the first escape 5 to the second escape 6 is almost the same as the conventional one, the compressed air pressure is high, so that the feeding time is 1.4 seconds. Since the feeding from the first escape to the second escape is performed before and after the welding time of the previous stud, the total welding process time is from 3.6 seconds to 2.0 seconds. Has been shortened to seconds. Further, it takes 0.6 seconds to feed from the second escape to the welding gun, which means that the feeding is stable over a longer time than the distance. Since the total welding process time for spot welding is the same as 2.0 seconds, mixed production with spot welding at the same station on the line is possible and the production tact is not affected.

4A to 4C show the operation of the second escape 6 corresponding to FIGS. 4B to 4C.

[0022]

According to the method and apparatus for supplying studs at high speed in stud welding of the present invention, the compressed air pressure is increased to feed the studs at high speed from the feeder to the second escape arranged near the welding gun. The compressed air pressure is reduced from the second escape to the welding gun so that stable feeding is performed, and while the stud welding is being performed, the first
By feeding the next stud from the escape to the second escape and making it stand by, the stud feeding speed is increased overall and the stud welding process time is shortened. By providing an escape device for feeding in the middle, the total welding process time was shortened from 3.6 seconds to 2.0 seconds for one stud,
With other studs, it was shortened from 2.6 seconds to 1.7 seconds, the production speed in the line was increased, and the supply of studs to the welding gun became stable and reliable, and the welding equipment started operating due to improper stud feeding. There is an advantage that there is no stoppage and there is no time loss due to line stoppage.

[Brief description of drawings]

FIG. 1 is an array diagram of each device in an automated device using a robot for stud welding according to the present invention.

FIG. 2 is a sectional view of a second escape device.

FIG. 3 is an operation explanatory view of a second escape device.

FIG. 4A is a welding process time chart by the stud welding automation device, and B is an operation explanatory diagram of the second escape device.

FIG. 5A is a welding process time chart by the conventional stud welding automation device, and B is an operation explanatory diagram of the first escape device.

[Explanation of symbols]

 1 Welding gun 2 Feeder 3 Power supply device 4 Robot 5 First escape 6 Second escape 8 Feed tube 9 Feed tube 10 Welding cable

Claims (3)

[Claims] 1. A compressed air pressure is increased from a feeder to a second escape arranged near the welding gun to feed a stud at a high speed, and then a compressed air pressure is reduced from the second escape to the welding gun for stable feeding. While trying to pay
By feeding the next stud from the first escape to the second escape and making it stand by while stud welding is being performed, the feeding speed of the stud is increased overall and the stud welding process time is shortened. A high-speed stud feeding method in automatic stud welding characterized by the above. 2. A stud automatic feeding device for stud welding, comprising a mechanism for receiving a stud fed from the feeding device and feeding it again in the middle of a stud feeding path from the feeding device to the welding gun. A high-speed stud feeder for automatic stud welding, which is equipped with an escape device and controls the feeder, escape device, and welding gun to reduce the total stud feeding process time. 3. A second escape device having a mechanism for receiving the stud fed from the feeding device and feeding it again in the middle of the stud feeding path from the feeding device to the welding gun, and a transfer bar in the main body. The transfer bar is slidably inserted and connected to the main body via the piston rod of the composite air cylinder joined to the main body so that the composite air cylinder slides the transfer bar in a predetermined stroke. A tube connection port that joins the feed tube and a pressure air supply port that supplies compressed air of a predetermined pressure are provided, a cushion is provided at a position facing the tube connection port, and a feed tube is provided at a position facing the pressure air supply port. The stud for automatic stud welding according to claim 2, wherein a tube connection port for joining the High speed feeding device.