JP2001018072A - Spot welding gun with timer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight spot welding gun provided with a transformer and a timer. SOLUTION: This spot welding gun is provided with a cylinder assembly 28 for driving an electricity conduction control means controlling the conduction between the electrodes and a moving side electrode holder at a side 16b opposite to a side part 16a where electrode holders 20, 24 for fitting electrodes 22, 26 in a body 16 fitted rotatably around the central axis of a bell-support 12 hung with a hanger. Further, as the electricity conduction control means, a connector part 52 connected with an outer electric source, a timer 34 for regulating electricity conduction time and the current value between both electrodes, a main transformer 32 for lowering the voltage from the outer electric source voltage imputted from the connector part to the welding voltage to be supplied to the electrode and a thyrister 44 for switching on/off the welding current generated by the main transformer are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to spot welding in which a material to be welded is pressurized by an electrode, a large current is supplied to the material within a short time, and a local weld is melted and joined by resistance heating. The present invention relates to a spot welding gun with a timer having a built-in timer for defining an energization time.

[0002]

2. Description of the Related Art Heretofore, spot welding has been widely used as a kind of resistance welding for welding thin metal plates. In particular, in this spot welding, the possibility of welding between dissimilar metals, the point of little heat influence, and the welding work is performed almost automatically, so that a uniform welding result is obtained without individual differences between workers. From what can be obtained, especially,
It is a welding technique that is very commonly used as a technique that responds to automation in automotive manufacturing technology.

[0003] In a spot welding method, it is common practice to first apply a low current to perform preheating, and then to apply a full current to perform welding. Here, the external power source is an AC 400 V of 50 to 60 Hz, the welding current is a low voltage of 10 V or less, and the current value is, for example, 10,000 to 50,000 A / square cm for mild steel (high electric conductivity). A larger current value is used for metal, and the energization time is set to be extremely short, for example, 0.3 seconds.

[0004] For this reason, a transformer for voltage transformation and a timer for accurately defining a short energization time are required. However, since these are heavy, they are usually provided by a spot welding gun. It is removed, placed on the floor of a work place or the like as an external device, and connected to a spot welding gun by an electric wire.

As a result, although the spot welding gun itself is reduced in weight, a large number of electric wires are connected, and there is a problem that the working range is limited. In order to solve this problem, if the connecting wires are set long, the power wires, in particular, have a considerably large thickness due to the high current flowing, making it difficult to route them and the workability will deteriorate. Was to occur.

[0006]

SUMMARY OF THE INVENTION From such a viewpoint,
Various methods of incorporating a transformer and a timer have been studied, for example, about 90 kg for a 20,000 A type and about 80 kg for a 16,000 A type. It has been pointed out that the inertia is large, the accurate positioning is difficult, and the workability is poor, and improvement is demanded. In addition, it has been pointed out that the weight balance between the front and rear is poor, and that a worker must always support the gun itself in order to maintain a horizontal posture.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The main object of the present invention is to provide a structure incorporating a transformer and a timer, which can reduce the weight and reduce the work inertia. An object of the present invention is to provide a spot welding gun with a timer capable of improving the performance.

Another object of the present invention is to provide a spot welding gun with a timer that has a good weight balance and requires substantially no external force for holding the posture.

[0009]

Means for Solving the Problems To solve the above-mentioned problems,
To achieve the object, a spot welding gun with a timer according to the present invention is, according to the description of claim 1, a bell support suspended on a hanger and having a circular opening inside,
A body supported by an operator and rotatably mounted around the central axis of the opening in a state penetrating the opening of the bell support in the thickness direction thereof, and a side of the bell support of the body; A pair of fixed-side and movable-side arms disposed on the arm, electrodes attached to the ends of the arms, and pressed against each other at a predetermined pressure in accordance with the movement of the movable-side electrode holder; And a power supply control means for controlling the power supply between the two electrodes, and a drive means for driving the movable electrode holder. The means includes: a connector unit connected to an external power supply; a timer for defining a time and a current value to be applied between the two electrodes; and a unit for lowering the external power supply voltage input from the connector unit to a control voltage. A down transformer, a main transformer for lowering an external power supply voltage input from the connector unit to a welding voltage for energizing between the two electrodes, and a thyristor for interrupting the welding current generated in the main transformer by the timer. It is characterized by:

According to a second aspect of the present invention, in the spot welding gun with a timer according to the second aspect of the present invention, the driving means is such that the electrode attached to the movable electrode holder is attached to the fixed electrode holder. And a cylinder assembly for moving the movable-side electrode holder in a direction to contact and separate the electrode.

According to a third aspect of the present invention, there is provided a spot welding gun with a timer, wherein the energization control means includes a temperature detector for detecting a heat generation temperature of the thyristor, and a detection result of the temperature detector. And a cooling means for cooling the thyristor.

According to a fourth aspect of the present invention, in the spot welding gun with a timer according to the present invention, the timer is provided with a trigger which is operated by the operator and which regulates the energization timing. It is characterized by having.

According to a fifth aspect of the present invention, there is provided a spot welding gun with a timer, wherein the other side of the body is entirely covered by a cover member.

According to a sixth aspect of the present invention, there is provided a spot welding gun with a timer according to the present invention, wherein the body has at least three parts interposed between the bell support and the body.
The bell support is rotatably supported by the plurality of roller members.

According to the seventh aspect of the present invention, in the spot welding gun with a timer according to the present invention, the weight on one side and the weight on the other side of the bell support are substantially equal to the whole weight. It is characterized by being balanced.

In the spot welding gun with a timer according to the present invention, the movable electrode holder is supported so as to be able to advance and retreat in the same direction as the extending direction of the movable electrode holder. It is characterized by things.

According to a ninth aspect of the present invention, there is provided a spot welding gun with a timer, wherein the cylinder assembly includes a cylinder having a drive axis extending in the same direction as the extending direction. Features.

According to a tenth aspect of the present invention, in the spot welding gun with a timer according to the tenth aspect, the movable-side electrode holder is rotatable around a predetermined support shaft on the one side of the body. It is characterized by being supported by.

According to the eleventh aspect of the present invention, in the spot welding gun with a timer, the cylinder assembly extends along a direction intersecting an extending direction of the fixed-side electrode holder. It is characterized by having.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a spot welding gun with a timer according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, first, the structure of a so-called C-type spot welding gun will be described, and then, the structure of an X-type spot welding gun will be additionally described.

As shown in FIGS. 1 and 2, the C-shaped spot welding gun 10 includes a bell support 12 suspended by a hanger arm (not shown) as a suspension fitting. A suspension arm 14 is integrally connected to the bell support 12, and the upper end of the suspension arm 14 is connected to a hanger arm (not shown), so that the spot welding gun 10 is free as a whole. It is suspended in a posture.

The above-described bell support 12 is formed in a substantially ring shape, and has a circular opening 12a formed in the center thereof in a state penetrating in the thickness direction. This opening 12a
A guide rail (not shown) is formed on the entire inner peripheral surface of the inner peripheral surface, so that a rolling contact roller, which will be described later, comes into rolling contact therewith.

The opening 12a of the bell support 12 has
The body (attachment body) in a state where it penetrates in the thickness direction and is rotatable around the central axis of the opening 12a.
16 are attached. The body 16 is directly supported by an operator, and will be described in detail later.
The weight balance is set so that the posture is maintained in a state of extending in a substantially horizontal direction with various parts and devices attached. In other words, the bell support 12 suspended from the hanger arm (not shown) via the suspension arm 14 in a state in which various parts and devices are attached maintains a substantially upright posture, and is attached thereto. The body 16 is supported to be rotatable about a substantially horizontal axis.

The body 16 has an outer peripheral surface portion facing the inner peripheral surface of the opening 12a. Three rolling contact rollers 18 are rotatably supported on the outer peripheral surface portion. ing. In this way, the body 16 is rotatably supported by the bell support 12 via the three rolling rollers 18.

Here, as described above, the body 16
Since the bell support 12 penetrates through the opening 12a in the thickness direction thereof, a front portion 16a protruding forward (one side) of the bell support 12 and a rear portion 16b protruding rearward (the other side) of the bell support 12 are provided. At the bell support 12.

A substantially L-shaped fixed-side electrode holder 20 is fixed to the lower portion of the front portion 16a of the body 16 so as to protrude forward (to the left in the drawing). It stands upright in the middle and terminates. A first electrode 22 is attached to the end face of the fixed-side electrode holder 22 facing the bell support 12 so as to extend rearward (to the right in the drawing).

On the upper part of the front portion 16a of the body 16, a substantially linear movable-side electrode holder 24 extends in the left-right direction in the figure (ie, the direction perpendicular to the bell support 12). It is movably supported along the same direction as the extension direction. A second electrode 26 is attached to the tip of the movable-side electrode holder 24 so as to extend forward (to the left in the drawing). The first and second electrodes 22 and 26 are arranged in a straight line so as to be aligned with each other.
They are pressed against each other at a predetermined pressure.

On the other hand, a cylinder assembly 28 constituting the above-described drive mechanism is mounted on an upper portion of a rear portion 16b of the body 16 adjacent to the bell support 12. Although not shown in detail, the cylinder assembly 28 includes a cylinder 30 having a drive axis extending in the same direction as the moving direction of the movable electrode holder 24, that is, a horizontal direction in the drawing. The side electrode holder 22 is connected to a piston rod (not shown) of the cylinder 30 via a connection mechanism (not shown).

The lower part of the rear portion 16b of the body 16 adjacent to the bell support 12 has an external power supply voltage (input voltage) of 400 V from a connector portion described later.
A main transformer 32 is mounted to reduce the voltage to a conduction voltage (welding voltage; for example, 4 V) for supplying a voltage between the electrodes 22 and 26.

Further, on the rear portion 16b of the body 16 further to the right of the cylinder assembly 28 in the figure, a timer 34 for regulating the current value of the welding current flowing between the two electrodes 22 and 26 and the conduction time is provided. It is installed in the state stored in the case. An operation handle 36 to be gripped by an operator is attached to the upper surface of the timer 34 in the drawing, and the operator operates to pull in a trigger 38 attached to the operation handle 36 to perform spot welding. The start timing is instructed to the timer 34. That is, this timer 34
Detects that the trigger 38 has been retracted,
For a predetermined time (for example, 0.3 seconds) set in advance,
At a preset current value, the welding current is applied to both electrode currents 22,2.
It is configured to control a thyristor, which will be described later, so as to flow between the six.

An area of the rear portion 16b of the body 16 below the cylinder assembly 28 and further to the right of the main transformer 32 in the figure is provided with an external power supply voltage input from the connector. Transformer 4 for reducing the voltage to a control voltage (for example, 24 V)
0, a CT coil 42 for adjusting the current value to a specified value, for example, 16,000 A, and the main transformer 32 described above.
The thyristor 44 that finally determines the welding current flowing between the two electrodes 22 and 26 by intermittently controlling the welding current generated by the timer 34 under the control of the timer 34, and a temperature detector that detects the temperature of the thyristor 44 (thermostat)
A thyristor protector 48 for protecting the thyristor 44 is provided.

The above-described thyristor 44 is a power control element as a high-speed electronic contactless switch, and specifically, is an SCR (Silicon Controlled).
Rectifier).

Here, the spot welding gun 10 includes:
Based on the temperature detected by the temperature detector 46, the thyristor 4
Although not shown in detail, a cooling mechanism that allows cooling water to flow so as to keep the temperature of 4 at a predetermined temperature, that is, so as not to rise from the predetermined temperature, is provided.

The rear portion 16b of the body 16 is covered with a cover member 50 except for a case that covers the timer 34. A connector 52 connected to an external power supply via a cable (not shown), a cooling water input port 54a for supplying cooling water to the cooling mechanism, and a cooling Discharge port 54b used for cooling water, an air input port 56a for supplying working compressed air to the cylinder assembly 28, and an air discharge port 56b for discharge
And are arranged.

As described above, in this embodiment, the two electrodes 22, 26 are provided on the rear portion 16b of the body 16.
A power supply control mechanism including a connector unit 52 for controlling the power supply between them, a timer 34, a CT coil 42, a down transformer 40, a main transformer 32, a thyristor 44, a thyristor protector 48, and the like, A cylinder assembly 28 is provided as driving means for driving the movable electrode holder. As a result, there is an advantage that the handling becomes extremely easy as compared with the related art in which a main transformer and a timer are provided outside and a cable is connected between them.

Here, the weight in the configuration in which the power supply control mechanism is built in will be verified.

In this embodiment, the maximum current is 20,000 A, the output is 38 kVA, and the compressed air pressure introduced into the cylinder assembly 28 is 5 kgf / cm 2.
The two electrodes 2 by this cylinder assembly 28
In the case where the pressure contact force between 2 and 26 is 230 kgf, bell support 12 2.0 kg hanging arm 14 3.3 kg body 16 4.4 kg 3 rolling contact rollers 18 0.2 kg fixed-side electrode holder 20 3.2 kg Movable electrode holder 24 1.2 kg Cylinder assembly 28 2.0 kg Main transformer 32 17.0 kg Timer 34 1.2 kg Operating handle 36 0.5 kg Trigger 38 0.4 kg Down transformer 40 … 1.2 kg CT coil 42… 0.2 kg Thyristor 44… 0.2 kg Cover member 50… 3.0 kg Others… About 4 kg Total about 44 kg.

As a result, the conventional spot welding gun equipped with a timer, that is, a type equipped with an energization control mechanism can be used in the range of 80 to 9
As compared with 0 kg, the weight is about half of the weight. As a result, the inertia when operating the spot welding gun 10 is small, the workability is extremely improved, and the effects such as accurate positioning are achieved. There is an advantage that can be reliably achieved.

Moreover, the weight and arrangement position of the components attached to the front portion 16a of the body 16 and the rear portion 16b of the body 16 are supported by using the bell support 12, which is a suspension point for the hanger arm, as a fulcrum. The weight and arrangement position of the parts are set such that the rotational moments of both parts are exactly balanced. As a result, in a free state where the spot welding gun 10 is hung on a hanger arm (not shown) and no external force acts,
The bell support 12 is held substantially upright, that is, the spot welding gun 10 itself is maintained in a posture extending substantially horizontally. Therefore, the operator can use this spot welding gun 1
0 can be handled very easily, and from this viewpoint, the effect of improving workability can be obtained.

It is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

For example, in the embodiment described above,
Although the present invention has been described as being applied to a C-type spot welding gun, it is needless to say that the present invention is not limited to such an application but can also be applied to an X-type spot welding gun. .

Referring to FIGS. 3 and 4, another embodiment according to the present invention will be described in detail when applied to an X-type spot welding gun. The same parts as those of the spot welding gun in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 3 and 4, in the X-shaped spot welding gun 10 ', the movable electrode holder 2
4 is rotatably supported by a front portion 16 a of the body 16 via a support shaft 58. For this reason, the fixed-side electrode holder 20 is formed in an inverted L-shape, is bent downward from the middle part, and the first electrode 22 is provided at the distal end surface of the fixed-side electrode holder 20 (that is, (A lower end surface) so as to protrude downward.

On the other hand, the movable-side electrode holder 24 is formed in an L-shape, is bent upward from an intermediate portion, and the second electrode 26 is connected to the distal end surface of the movable-side electrode holder 24 [ie, , Upper end surface) in a state protruding upward. The first and second electrodes 22, 26
As in the case of the above-mentioned I-type, they can be abutted in a state where they are aligned with each other.

In the X-shaped embodiment, since the movable electrode holder 24 needs to be swingably driven by the second electrode 26 with a sufficient stroke, the cylinder assembly 28 is provided at the rear portion of the body 16. The drive axis is attached to the rear part of the rear part 16b in the vertical direction in the drawing. For this reason, the timer 34 is attached to an upper portion of the rear portion 16b of the body 16 adjacent to the bell support 12 in the drawing.

On the other hand, the main transformer 32 is
The rear portion 16b is attached to a portion adjacent to the bell support 12 and located immediately below the timer 34. As a result, the rear portion 16b of the body 16
In an area located below the cylinder assembly 28 and the main transformer 32 in the figure, as in the case of the I type,
A down transformer 40, a CT coil 42, a thyristor 44, a temperature detector (thermostat) 46, and a thyristor protector 48 are provided.

As described above, in the embodiment relating to the X-shape, similarly to the above-mentioned I-shape, the connector portion for controlling the conduction between the two electrodes 22 and 26 is provided on the rear portion 16b of the body 16. 52, timer 34, CT coil 42, down transformer 40, main transformer 32
, A current control mechanism including a thyristor 44, a thyristor protector 48, and the like, and a cylinder assembly 28 as driving means for driving the movable-side electrode holder. As a result, the same operation and effect as those of the above-mentioned I type can be achieved.

[0048]

As described in detail above, according to the present invention, even with a structure incorporating a transformer and a timer, a timer with a reduced weight, a reduced inertia, and improved workability can be provided. A spot welding gun will be provided.

Further, according to the present invention, there is provided a spot welding gun with a timer having a good weight balance and requiring substantially no external force for holding the posture.

[0050]

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment in which a spot welding gun with a timer according to the present invention is applied to a C type.

FIG. 2 is a right side view showing the configuration of a C-type spot welding gun with a timer shown in FIG.

FIG. 3 is a front view showing an embodiment in which the spot welding gun with a timer according to the present invention is applied to an X type.

FIG. 4 is a right side view showing a configuration of the X-type spot welding gun with a timer shown in FIG. 3;

[Explanation of symbols]

 10 (10 ′) Spot welding gun with timer 12 Bell support 12a Opening 14 Hanging arm 16 Body 16a Front part 16b Back part 18 Rolling contact roller 20 Fixed side electrode holder 22 First electrode 24 Movable side electrode holder 26 Second Electrode 28 Cylinder assembly 30 Cylinder 32 Main transformer 34 Timer 36 Operation handle 38 Trigger 40 Down transformer 42 CT coil 44 Thyristor 46 Temperature detector 48 Thyristor protector 50 Cover member 52 Connector 54a Cooling water input port 54b Cooling water discharge port 56a Air input Port 56b Air exhaust port 58 Support shaft

Claims (11)

[Claims] 1. A bell support hung on a hanger and having a circular opening inside, a state in which the opening of the bell support penetrates in the thickness direction thereof, and is rotated about a central axis of the opening. A body freely mounted and supported by an operator; a pair of fixed and movable arms disposed on one side of the bell support of the body; and a movable side electrode attached to a tip of each arm. An electrode that is pressed against each other at a predetermined pressure in accordance with the movement of the holder; and the one side of the body is disposed on the other side opposite to the bell support, and controls energization between the electrodes. Energizing control means, and a driving means for driving the movable-side electrode holder, the energizing control means defines a connector portion connected to an external power supply, and a welding time and a welding current value to be energized between both electrodes. Do An external power supply voltage input from the connector unit; and a down transformer for reducing an external power supply voltage input from the connector unit to a control voltage. A spot welding gun with a timer, comprising: a main transformer for lowering the pressure to a welding voltage to be applied between the main transformer; and a thyristor for interrupting the welding current generated in the main transformer by the timer. 2. The drive means includes a cylinder assembly for moving the movable electrode holder in a direction in which an electrode attached to the movable electrode holder comes into contact with or separates from an electrode attached to the fixed electrode holder. The spot welding gun with a timer according to claim 1, wherein: 3. The apparatus according to claim 1, wherein said energization control means further includes a temperature detector for detecting a heat generation temperature of the thyristor, and a cooling means for cooling the thyristor based on a detection result of the temperature detector. The spot welding gun with timer described. 4. The spot welding gun with a timer according to claim 1, wherein the timer is provided with a trigger which is operated by the operator and defines the energization timing. 5. The spot welding gun according to claim 1, wherein the other side of the body is entirely covered by a cover member. 6. The body according to claim 1, wherein the body is rotatably supported by the bell support by at least three roller members interposed between the body and the bell support. Spot welding gun with timer. 7. The spot welding with a timer according to claim 1, wherein the weight on one side of the bell support and the weight on the other side of the overall weight are substantially balanced. gun. 8. The timer with a timer according to claim 1, wherein the movable electrode holder is supported so as to be able to advance and retreat along the same direction as the extension direction of the movable electrode holder. Spot welding gun. 9. The spot welding gun with a timer according to claim 8, wherein the cylinder assembly includes a cylinder having a drive axis extending in the same direction as the extending direction. 10. The movable electrode holder according to claim 1, wherein the movable electrode holder is supported by the one side of the body so as to be swingable around a predetermined support shaft. The spot welding gun with a timer according to the item. 11. The spot welding gun with a timer according to claim 10, wherein the cylinder assembly includes a cylinder extending along a direction intersecting with an extension direction of the fixed-side electrode holder. .