JPH079155A - Upset welding equipment - Google Patents

Abstract

PURPOSE:To realize welding according to suitable welding conditions in accordance with a cross-sectional area of members and to obtain stable welding quality. CONSTITUTION:The upset welding equipment is provided with a resistance welding machine which butts, pressurizes and welds the end faces in a state with both ends of ringlike pipes W for steering wheels held by holding parts 11, a feed sensor 4 which detects the quantity of rotation of a roll device and measures the feed quantity of the pipes W and a load cell 5 which is arranged on a conveying member to convey the ringlike pipes W which are bent and cut in a ringlike shape to a pressure device and measures the weight of the ringlike pipes W. The upset welding equipment is further provided with a diameter sensor 6 which measures the diameter of the pipes W by detecting the displacement quantity of rolls of the roll device in opposition and a main controller 7 having a corss-sectional area arithmetic circuit 71 which obtains the cross-sectional area of the pipe members based on the measured feed quantity and weight of the pipes W and a welding condition determining circuit 74 which determines the welding conditions based on the diameter and cross-sectional area of the pipes W measured by the diameter sensor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upset welding apparatus for determining a sectional area of a member based on the length and weight of the member and performing welding under appropriate welding conditions according to the sectional area.

[0002]

2. Description of the Related Art Some conventional upset welders equipped with a constant-current control type welding control device, once the welding conditions are set, are controlled in accordance with the set constant welding conditions.

[0003]

Since the conventional upset welder described above is mechanically controlled in accordance with set welding conditions, the size, thickness, or cross-sectional area of the member to be welded changes. Then, since the current density changes even if the welding current is constant, there is a problem that the melted state of the welded part changes and stable welding quality cannot be obtained.

Therefore, the present inventor conducted a systematic experiment to determine the length and weight of the member to be welded, the cross-sectional area of the welded portion based on this, and weld under the welding conditions corresponding to this cross-sectional area. Focusing on the technical idea of the present invention, as a result of further research and development, a book that achieves welding under appropriate welding conditions according to the cross-sectional area of the member to be welded and achieves stable welding quality The invention was reached.

[0005]

An upset welding device of the present invention (a first invention according to claim 1) is a pressurizing device for pressing a member whose end portion is abutted by a gripping portion, and the member. At least a pair of electrodes arranged to face each other across the butt end of, an energizing device for passing a welding current to the pair of electrodes, a length sensor for measuring the length of the member,
A weight sensor for measuring the weight of the member, the cross-sectional area of the member is obtained based on the length measured by the length sensor and the weight measured by the weight sensor, and welding conditions corresponding to the cross-sectional area are output to the current-carrying device. And a control device that operates.

The upset welding device of the present invention (the second invention according to claim 2) is a pressurizing device for holding both ends of a ring-shaped pipe member by holding parts and abutting both end faces against each other. And at least a pair of electrodes arranged so as to face each other with the abutted end surface of the pipe member interposed therebetween, an energizing device for supplying a welding current to the pair of electrodes, and a pipe member before being formed into a ring shape. A feed sensor that measures the feed amount, a load cell that is arranged in a member that locks a pipe member formed in a ring shape and that measures the weight of the pipe member, a diameter sensor that measures the diameter of the pipe member, and the feed The cross-sectional area of the pipe member is obtained based on the feed amount and the weight of the pipe member measured by the sensor and the load cell, and is stored in advance based on the cross-sectional area and the diameter of the pipe member measured by the diameter sensor. And it is upset amount and the corresponding welding conditions from the relationship between the welding conditions are those comprising a control device for outputting the power device.

[0007]

In the upset welding apparatus of the first aspect of the present invention, the length sensor measures the length of the member, the weight sensor measures the weight of the member, and the controller measures the length and weight of the member. Based on the above, the cross-sectional area of the member is obtained, the welding condition corresponding to this cross-sectional area is output to the energizing device, and the energizing device welds the end portion of the member with the welding current corresponding to this welding condition.

In the upset welding apparatus of the second invention having the above-mentioned structure, the length of the pipe member is measured by the feed sensor, the weight of the pipe member is determined by the load cell, and the length and weight of the member are measured by the control device. The cross-sectional area of the member is calculated based on this, the welding conditions corresponding to this cross-sectional area and the diameter of the pipe member measured by the diameter sensor are extracted and output to the energizing device, and the energizing device responds to this extracted welding condition. The welding current is used to weld both ends of the ring-shaped pipe member.

[0009]

According to the upset welding apparatus of the first aspect of the present invention, which achieves the above-described operation, welding is performed under appropriate welding conditions according to the sectional area of the member based on the length and weight of the member detected by the length sensor and the weight sensor. In addition, there is an effect that stable welding quality can be obtained.

The upset welding apparatus of the second invention having the above-mentioned operation is adapted to the cross-sectional area of the pipe member based on the length and weight of the member detected by the length sensor and the weight sensor and the diameter of the pipe member detected by the diameter sensor. It is possible to realize welding under optimum welding conditions and obtain more stable welding quality.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The upset welding apparatus of the first embodiment is an embodiment of the first invention and the second invention, and the present invention is applied to both ends of a ring-shaped pipe member for a core metal of a steering wheel. It is applied to welding.

The upset welding apparatus of the first embodiment is shown in FIG.
As shown in FIG. 14, a pressurizing device 1 having a pressurizing portion 12 for pressing the end faces by abutting the end portions of the ring-shaped pipe W for the steering wheel in a state of being gripped by the gripping portions 11, and inside the gripping portion 11. A resistance welding machine including a pair of electrodes 2 arranged in contact with the ring-shaped pipe W, and an energization device 3 for supplying a welding current to the pair of electrodes to realize welding conditions according to the setting. And a feed sensor 4 for measuring the feed amount of the pipe W by detecting the rotation amount of the roll device, and a feed member for feeding the ring-shaped pipe W, which is cut after being bent into a ring shape, to a pressurizing device. ,
The load cell 5 for measuring the weight of the ring-shaped pipe W, the diameter sensor 6 for measuring the diameter of the pipe W by detecting the displacement amount of the roll of the opposing roll device, the feed sensor 4 and the load cell 5 are used for the measurement. Pipe W
A cross-sectional area calculation circuit 71 for determining the cross-sectional area of the pipe based on the feed amount and weight of the pipe, and a welding condition determination circuit 74 for determining the welding condition based on the cross-sectional area and the diameter of the pipe W measured by the diameter sensor 6 And a control device 7.

A work processing device 8 for processing a pipe coil material P into a ring-shaped pipe W which is a work is composed of a plurality of roll devices as shown in FIG. 9 and straightens the pipe coil material P to measure its length. A straight length measuring part 81 and a bending cutting part 82 which bends the straightened pipe material P to a constant curvature and then cuts it at a constant length. W is placed on the grip portion 11 of the pressurizing device 1 of the upset welding device by the carrying member 84 of the carrying device 83.

The grip 11 of the pressurizing device 1 of the welding machine is shown in FIG.
The both ends of the ring-shaped pipe W processed by the work processing apparatus shown in Fig. 2 are separated, and the upper gripping portion 11U which moves up and down is fixed by the pressure cylinder as shown in Figs. 1, 4 and 5. The lower grip portion 11D is configured to approach and grip the lower grip portion 11D.

Pressure unit 12 of pressure device 1, FIG. 1 and FIG.
By locking the pressure cylinder 12C to one of the grips as shown in Fig. 2 and fixing the other grip, the pressure of the pressure cylinder 12C causes one grip to approach the other grip. The end faces of the ring-shaped pipe are brought into contact with each other, and
It has a structure capable of pressurizing according to a trapezoidal pattern SV as shown in FIG.

As shown in FIG. 5, the pair of electrodes 2 are arranged so as to oppose each other with the abutting end face of the ring-shaped pipe W sandwiched therebetween.

The current-carrying device 3 is a current-carrying part 3 consisting of a step-up transformer 3T connected to a pair of electrodes 2 as shown in FIG.
1 and a welding condition control unit 32 that outputs a control signal to the energization unit 31 to enable energization corresponding to the set welding conditions, and three energization pulses C1 as shown in FIG.
It has a configuration that enables energization control of welding current as indicated by C2 and C3.

In FIG. 10, the first energizing pulse is a preheating pulse C1 for preheating the welded portion, and a portion gradually increasing in the first half is formed. The welding current C1 and the pulse time t1 are set, and the second main welding is performed. The main welding pulse C2 for performing welding is for welding for a short pulse time t2 due to the maximum current C2, and the last energizing pulse C3 is for holding heat for tempering, and gradually decreases in the latter half. The welding current C3 and the pulse time t3 are set.

As shown in FIGS. 6 and 7, the feed sensor 4 is disposed so as to face each other in the length measuring section 81 for measuring the pipe W, and comes into contact with the pipe W to feed the pipe W upward in FIG. One of the roll devices 8RA and 8RB
The encoder 40 is disposed on the rotation shaft of the roll RA of the RA and rotates integrally with the roll RA. The feed amount of the pipe W is determined by the amount of rotation of the roll RA. The length is detected.

As shown in FIG. 8, the load cell 5 holds the ring-shaped pipe W bent and cut to have a constant curvature and conveys it from the bending / cutting portion 82 to the pressurizing device 1 by a conveying device 83.
It is composed of a piezoelectric type load cell interposed in a sandwich shape in the middle of the carrying member 84, and can output an electric output according to the weight of the ring-shaped pipe W to be carried.

As shown in FIGS. 6 and 7, the diameter sensor 6 is a magnetic device provided on the flanges of the air cylinders EA and EB for pressing the rolls RA and RB of the roll devices 8RA and 8RB for pinching the pipe W. Displacement sensor 6A,
6B, by calculating the relative distance between the rolls RA and RB connected to the piston (not shown) inserted in the air cylinders EA and EB via a rod and the flanges of the air cylinders EA and EB. , Pipe W
Of the diameter of the sensor.

As shown in FIG. 4, the upset sensor 9A grips the ring-shaped pipe to grip the movable side 11U.
A rod-shaped member 91 that moves integrally with the member 1M including 11D.
And a potentiometer 92 arranged on the member 1F having the fixed-side grip portion 11D, and the upset amount of the ring-shaped pipe W during welding can be output as an electric signal.

The current sensor 9B is arranged on the cable 5C between the current-carrying portion 31 and the electrode 2 as shown in FIG. 5, and has a structure for detecting the flowing current from the eddy current formed by the current probe. is there.

The card reader 10 is configured to read and output setting conditions corresponding to the material, size, etc. of the ring-shaped pipe member for welding set on the card.

The main controller 7 has a cross-sectional area calculating circuit 71 for calculating the cross-sectional area of the pipe member, an upset amount judging circuit 72 for judging the upset amount, a current judging circuit 73 for judging the welding current, and welding. And a condition determining circuit 74.

The cross-sectional area calculation circuit 71 has a conveying member 84 having a constant weight from the electric output of the load cell 5.
Is calculated by subtracting the weight of the ring-shaped pipe W, and the weight is divided by the product of the length of the ring-shaped pipe W output by the feed sensor 4 and the known specific gravity of the ring-shaped pipe W to obtain the ring-shaped pipe W. It has a configuration capable of calculating the cross-sectional area of the pipe W.

As shown in FIG. 4, the upset amount determination circuit 72 sets the zero point at the time when the welding start signal is output from the output of the potentiometer 92 supplied from the upset sensor 9A at the time when the welding end signal is output. By subtracting the output of the potentiometer 92, the upset amount is calculated, it is determined whether or not the upset amount is within the allowable range determined by the setting conditions set by the card reader 10, and the value is outside the allowable range that does not conform to the welding conditions. When the ring-shaped pipe is welded, an abnormal stop signal is output.

The current discriminating circuit 72 follows the change of the eddy current signal output from the current sensor 9B and discriminates whether the current is within the permissible range of the current determined by the set condition. Is capable of outputting an abnormal signal of welding current and an abnormal signal of energization time.

The welding condition determining circuit 74 is based on the sectional area signal output by the sectional area calculating circuit 71 and the diameter signal of the ring-shaped pipe W output by the diameter sensor 6, for example, welding current or welding pressure, energizing time, etc. Is basically configured to output a signal for controlling.

The welding condition determination circuit 74 can output a stop signal to the resistance welding machine when any of the upset amount determination circuit 71 and the current determination circuit 72 has an abnormality in the upset amount, the welding current or the energization time. Consists of

In the upset welding apparatus of the first embodiment having the above-described structure, as shown in the control flow of FIG. 9, after the pipe coil material P is straightened in the straightening measuring section 81 of the work processing device 8, the roll is rolled. The diameter of the pipe W is measured by the diameter sensor 6 composed of the magnetic displacement sensors 6A and 6B arranged in the air cylinders EA and EB that drive the devices 8RA and 8RB.

Next, the feed amount of the pipe W supplied to the bending / cutting portion 82, that is, the length of the pipe W is determined by the feed sensor 4 constituted by the encoder 40 arranged on the rotary shaft of the roll RA of the roll device 8RA. To be measured.

The ring-shaped pipe W, which is cut after being bent to a certain curvature in the bending / cutting section 82, is conveyed by the conveying device 83.
When transported by, the weight is measured by the load cell 5 arranged on the transport member 84 that locks the ring-shaped pipe W.

Cross-sectional area calculation circuit 71 of main controller 7
Calculates the weight of only the ring-shaped pipe W by subtracting the known weight of the conveying member from the electrical output of the load cell 5, and calculates the weight and the length and specific gravity of the ring-shaped pipe W which is the output of the feed sensor 4. The cross-sectional area of the ring-shaped pipe W is calculated by and.

That is, as shown in FIG.
According to the measurement performed by the present inventor as an example of bending a 7 mm pipe into a ring having a radius of 17.7 cm, the relationship between the plate thickness of the pipe and the cross-sectional area of the joint has a proportional relationship as shown in FIG. The relationship between the pipe plate thickness and the pipe ring weight has a proportional relationship as shown in FIG. Even with a pipe having a standard thickness of 1.2 mm, 1.05 shown by a broken line in FIG.
The plate thickness varies in the range of ˜1.35, and the weight also varies in the range of 338 g to 424 g. From the relationships of FIGS. 12 and 13, the relationship between the cross-sectional area of the pipe joint and the weight of the pipe ring has a proportional relationship as shown in FIG. The cross-sectional area calculation circuit 71 pays attention to the proportional relationship between the cross-sectional area of the pipe and the weight, and also in consideration of the variation in the length of the pipe ring, finally, the ring-shaped pipe W
The cross-sectional area of is calculated.

When the signals detected by the respective sensors are abnormal in pipe diameter, feed and cross-sectional area (plate thickness) with respect to the setting conditions set by the card in the card reader 10, the main controller 7 performs welding. The machine stop signal is output.

The cross-sectional area calculation circuit 71 selects the light, medium, and heavy levels corresponding to the pipe diameter from the output of the diameter sensor 6, and the calculated cross-sectional area is selected from the three light, middle, and heavy levels. The welding condition 1, the welding condition 2, and the welding condition 3 which are set so that the level of the current density of the welding stored in advance is determined by determining which one of the levels is applicable. To output any one of the welding conditions corresponding to the corresponding level of light, medium and heavy.

The welding condition determining circuit 74 tentatively determines the welding condition based on the welding condition output by the cross-sectional area calculating circuit 71 and the diameter of the pipe W measured by the diameter sensor 6.

By the operation of the pressurizing cylinder 11C of the pressurizing device 1, the pressurizing part 1U is gripped by the gripping parts 11U and 11D.
After the ring-shaped pipes W are brought into contact with each other by the second pressurizing cylinder 12C and brought into contact with each other, welding is performed under the welding conditions provisionally determined by the welding condition determination circuit 74, and the upset sensor 9
Welding conditions such as welding current and energizing time and upset amount are measured by A and the current sensor 9B, and the presence or absence of welding abnormality and penetration abnormality is confirmed. If there is no abnormality, the above optimum welding conditions are output. is there.

In the energizing device 3, the welding conditions output by the welding condition determining circuit 74 corresponding to the setting conditions read by the card reader 10 and the cross-sectional area of the pipe member determined by the length and weight of the pipe W and the diameter of the pipe W are output. According to FIG.
Preheating waveform C1, main welding waveform C2 and heat retention waveform C shown in
The welding current of No. 3 is applied to the pair of electrodes 2 to act on the butt end faces to perform welding.

In the upset welding apparatus of the first aspect of the present invention, when the cross-sectional area (plate thickness) of the ring-shaped pipe, which is the work W, gradually changes, the cross-sectional area of the pipe W changes (decreases or increases). ), The welding conditions are determined accordingly, and welding is performed under the determined appropriate welding conditions, so appropriate welding is realized according to changes in the cross-sectional area of the workpiece, and defective welding is prevented. Has the effect of doing.

The upset welding apparatus of the first embodiment is
If the upset amount, welding current, and welding time exceed the allowable range, an error will be notified and the product will stop, so defective welding products can be detected and removed, and due to the difference between the setting conditions and the workpiece. When a defective welding product continuously appears, it is possible to prevent it by changing the setting condition according to the work.

The embodiments described above are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

In the above-mentioned first embodiment, the feed amount (pipe length) is detected by an encoder as an example. However, according to the present invention, a disk having teeth formed on the rotary shaft of the roll is fixed magnetically. It is also possible to detect the feed amount by detecting the rotation angle.

In the first embodiment described above, the weight of the ring-shaped pipe W is detected by the piezoelectric load cell as an example.
As the present invention, as shown in FIG. 15, a step of adopting a load cell RS having a wire strain gauge and a semiconductor strain gauge attached to a strain-flexing portion, or performing a weight measurement in a weight measuring portion before welding a ring pipe. It is also possible to provide.

In the first embodiment described above, the diameter sensor is
As an example, the magnetic displacement sensor detects each displacement of the pair of rolls RA and RB to detect the diameter of the pipe W. However, in the present invention, one roll is fixed, and the displacement of the movable roll is a stylus type. It is also possible to detect the diameter of the pipe W by detecting it with the above sensor.

As shown in FIGS. 16 and 17, the diameter sensor measures two displacements of a roller which is in contact with the pipe W up and down and rotates by two mechanical or optical electrometers 6C and 6D. The diameter of the pipe W can be calculated by the arithmetic circuit 6E from the output of the displacement meter.

In the above-described first embodiment, an example in which control is performed under three welding conditions corresponding to three levels of cross-sectional area: light, medium, and heavy has been described.
It is also possible to weld at a welding current density that is proportional to the cross-sectional area of.

In the above-described first embodiment, an example in which the welding current is changed as the welding condition is representatively described, but the present invention may change the energizing time or the applied pressure, or the welding current or the energizing current may be changed. It is also possible to comprehensively control the three factors of time and pressure.

[Brief description of drawings]

FIG. 1 is a front view showing an upset welding apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view showing the upset welding apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing an upset welding device of a first embodiment.

FIG. 4 is an enlarged view showing a pressure device and a sensor according to the first embodiment.

FIG. 5 is a block diagram showing basic control of the upset amount of the first embodiment device.

FIG. 6 is a plan view showing a roll device and a diameter sensor of the first embodiment.

FIG. 7 is a side view showing a roll device and a feed sensor of the first embodiment.

FIG. 8 is a partially enlarged view showing a carrying member and a load cell of the first embodiment.

FIG. 9 is a perspective view showing an upset welding device and a work processing device of the first embodiment.

FIG. 10 is a diagram showing a pressurizing waveform and a welding current waveform of the first embodiment.

FIG. 11 is a chart showing the control flow of the first embodiment device.

FIG. 12 is a diagram showing the relationship between the plate thickness of the pipe and the area of the joint.

FIG. 13 is a diagram showing the relationship between the plate thickness of the pipe and the weight of the pipe ring.

FIG. 14 is a diagram showing the relationship between the cross-sectional area of the joint portion of the pipe and the weight of the pipe ring.

FIG. 15 is a partially enlarged view showing another example of the transport member and the load cell.

FIG. 16 is a front view showing another example of the diameter sensor.

FIG. 17 is a side view showing another example of the diameter sensor.

[Explanation of symbols]

 1 Pressurizing Device 2 Pair of Electrodes 3 Energizing Device 4 Feed Sensor 5 Load Cell 6 Diameter Sensor 7 Main Control Device 8 Work Processing Device 9A Upset Sensor 9B Current Sensor 10 Card Reader 11, 11U, 11D Grip 1M Movable Member 1F Fixed Member 12 Pressure unit 3T Step-up transformer 31 Current-carrying unit 32 Welding condition control unit 40 Encoder 5C Cable 6A, 6B Magnetic displacement sensor 71 Cross-sectional area calculation circuit 72 Upset amount determination circuit 73 Current determination circuit 74 Welding condition determination circuit 81 Corrective length measurement unit 82 Bending / cutting section 83 Conveying device 84 Conveying member 8RA, 8RB Roll device RA, RB roll EA, EB Air cylinder

Claims (2)

[Claims] 1. A pressurizing device for gripping and pressing a member whose end portion is abutted by a gripping portion, at least a pair of electrodes arranged to face each other with the abutting end portion of the member interposed therebetween, and the pair of electrodes. An energizing device for energizing a welding current to the electrode, a length sensor for measuring the length of the member, a weight sensor for measuring the weight of the member, a length measured by the length sensor and a weight measured by the weight sensor. An upset welding device, comprising: a controller for determining a cross-sectional area of the member based on the above and outputting welding conditions according to the cross-sectional area to an energizing device. 2. A pressurizing device for holding both ends of a ring-shaped pipe member by holding parts and abutting and pressing both end faces, and a pressing device opposed to each other with the abutted end face of the pipe member interposed therebetween. At least a pair of electrodes provided, an energization device that applies a welding current to the pair of electrodes, a feed sensor that measures the feed amount of the pipe member before being formed into a ring shape, and a pipe member formed into a ring shape A load cell disposed on a member for locking the pipe member for measuring the weight of the pipe member, a diameter sensor for measuring the diameter of the pipe member, and a pipe based on the feed amount and the weight of the pipe member measured by the feed sensor and the load cell. The cross-sectional area of the member is obtained, and based on this cross-sectional area and the diameter of the pipe member measured by the diameter sensor, corresponding welding is performed from the relationship between the preset upset amount and welding conditions. An upset welding device, comprising: a control device that outputs conditions to an energizing device.