JPH0292472A - Pressure device for resistance welding - Google Patents

Abstract

PURPOSE:To execute welding of a high quality by connecting both arms of an X-type gun by a spring line material, and also, holding the gun in the vicinity of a fitting part of the connecting spring line material, and placing plural spring line materials roughly in parallel to both the arms. CONSTITUTION:Both arms 11, 12 of an X-type gun and a connecting spring 13 are formed to an H type by a plastic base composite material having a high resistance value, and both the arms 11, 12 are made to a high spring constant. To the connecting spring 13, pressing force of about 1/3 of pressing force at the time of welding between electrode tips is applied. In this state, by operating a return side of a cylinder, the tip is opened and the connecting spring is pressed and bent. When the cylinder is switched to the pressure side at the time of welding, accumulated spring pressure is released suddenly and superposed on force of the cylinder, the tip 5 collides violently with an object to be welded, straightens it instantaneously and contact conformity is formed. Thereafter, pressing force at the time of welding becomes small by a portion required for straightening. Since the spring constant of the arms 11, 12 is high, it conforms to expansion and contraction at the time of forming a nugget.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressurizing device for resistance welding. In particular, the present invention relates to an X-shaped pressure gun device suitable for a portable gun for welding robots.

Pressure guns for resistance welding, especially pressure guns used in welding robots, are desired to be as small and lightweight as possible.

For applying pressure during welding, an X-shaped pressure gun is often used that applies cylinder force to the tip of the electrode tip via a lever.

(Prior Art) A conventional X-type gun has an insulated fulcrum in the middle of two arms made of conductive casting, with a cylinder attached to one end and an electrode tip attached to the other end. In addition, the gun was held by a mounting plate that could swing around a fulcrum shaft, allowing it to be equalized when pressurized.

(Problems to be solved by the invention) In the conventional X-type gun, a large cylinder is required to apply several hundred kilograms of pressure during the pressurization process, and conversely, during the process between the electrodes, the cylinder The force between the electrodes is simply 1
It is rarely used in M-kunomi.

In addition, the lever fulcrum supports the enormous force during pressurization while maintaining accuracy and swings easily, and is also equipped with insulation and a member that equalizes and holds the gun itself, so the overall volume is reduced. It is also necessary to protect the large, swinging fulcrum from dust, making the entire structure compact, lightweight, and rigid.

It was difficult to make a gun with precision.

Therefore, if the gun is to be attached to a robot, the robot must have a large excess force.

Furthermore, even if an attempt was made to make the gun itself small and lightweight, the gun itself had to be made of a cast product with low strength due to its complicated shape and dimensions, and the gun arm itself was easily bent, making it difficult to achieve optimal welding.

(Means for Solving the Problems) The present invention differs from the conventional uniform pressurization method in that the pressurization process is applied to the initial "contact familiarization pressurization" and the expansion and contraction that occurs during nugget formation. The following "additional pressure" is divided into [Wg percussion familiarization pressure] and [highly responsive follow-up pressure], and the corresponding pressure is applied to each, reducing the overall pressure. , the entire pressure gun is made of a ``lightweight spring with a high spring constant'' (a high frequency spring).

Therefore, in addition to the conventional welding condition setting elements, the electrode
By adding "pressurization speed" and "immediate response," it is possible to perform stable welding with lower pressure holding force and welding current than conventional methods.

(Function) The feature of the present invention is that the fulcrum part, which is the starting point of the swing of the X-type gun opening lever, is replaced with a "swing spring" that bends and swings the spring strip material.
The whole thing was made simple and light.

The gun holding section should be held near the attachment points of the swing springs on both arms (with parallel plate springs) to stabilize the position of the electrode tip and provide equalization during pressurization.

The bending pressure of the oscillating spring is applied between the electrodes in advance to preload it, thereby reducing the diameter of the pressurizing cylinder.

Utilizing the return force of the cylinder, pressure is accumulated in the spring and applied with an impact to form a "contact conformity", which lowers the pressure when energized.

(Even in the case of materials that cannot be subjected to I-stroke pressure, the cylinder diameter becomes smaller due to the combination of the initial spring pressure and the cylinder pressure, increasing the spring constant of the pressure system.) The electrode tip is moved by expansion and contraction during nugget formation. In order to make the side "highly responsive with less inertia", the whole "
For example, the spring has a high spring constant.

(When forming a weld nugget, the nugget expands by about 10% of the plate thickness and then rapidly contracts.

At this time, if the electrode tip side lacks rigidity and has large inertia, the contact surface pressure between the tip and the surface to be welded decreases, causing dust.

) Therefore, each part is configured to act as a stiff and light spring, and these parts are assembled to form a light spring with a high spring constant.

(Example) ■ Both arms 11 and 12 of the X-type gun and the connecting spring 13 are
1] integrally made of a high resistance plastic matrix composite material, both arms 11, 12 are made of high spring constant springs.

In particular, the arm has sufficient strength so that only the tip part does not bend and the entire H-shaped frame becomes a spring with a high spring constant.

Further, the connecting spring 13 has a pressing force applied to the electrode tip portion that is about ⅓ of the pressing force required for welding. (Preload) (This pressing force is determined by the cap of the workpiece to be welded.) In this state, if the cylinder is returned and opened, an opening is formed between the tips, and the connection spring 13 is further compressed and bent.

(The state in which pressure is accumulated in the connecting arm is normally held in this state.) (In this state, the force of the cylinder is fully open.) When the cylinder is switched to the pressing side during welding, the accumulated spring pressure is suddenly released. As a result, the tip 5 is combined with the force of the cylinder and collides with the surface to be welded, and the energy instantly straightens the surface to be welded, thereby forming contact conformity.

(Generally, the surface to be welded by stacking press-formed plates has poor flatness when the plates meet, so a large pressure force is required during conventional welding to also correct this.) (When welding current is applied, the pressure of the accumulator spring Approximately 1/3 of the preload is added to approximately 2/3 of the pressure from the cylinder.) (This impulsive pressure promotes self-regeneration of the tip by turning it into a mushroom shape, and the plated steel plate (Suitable for welding.) After the surface to be welded is straightened by impact pressure and a contact conformation is formed, the pressure during welding is reduced by the amount required for straightening, so the deflection of arms 11 and 12 is also small. .

Furthermore, since the arms 11 and 12 are made of a plastic matrix composite material and have a rigid spring, the arm itself has little deflection, and the entire arm is lightweight and has a high spring constant, making it a strong spring that can quickly respond to rapid expansion and contraction when forming a weld nugget. , it is possible to perform highly stable welding.

(If the spring constant of the gun itself is low and the inertia is large, the quick response will be poor and a pressure difference will occur at the tip of the tip, causing dust to easily occur).

As described above, since the connection spring 13 serves both as a preload and as a connection using a conventional fulcrum, the gun can be made overall small, lightweight, and highly rigid.

(For conventional X-type guns, the fulcrum clevis swings 1M degrees.

Because it also serves as strength, insulation, and equalize shaft 1, the clevis is large and it is difficult to prevent dust from bearing.) (Connection spring 1
(The cylinder may be fixed to one arm by taking advantage of the free bending of 3).

Further, near the attachment point of the connection spring 13, equalized leaf springs 21, 22 arranged in parallel are held by a fixing plate 23.

Therefore, when the workpiece to be welded is pressurized from above and below, the gun itself equalizes in parallel due to the bending of the equalize leaf springs 21 and 22.

In addition, the leaf springs 21 and 22 regulate the distance between the fixing plate 23 and the attachment part of the connecting spring 13, determine the lengthwise position of the connecting arm 11.12, and prevent the tip of the electrode from shifting. be done.

The bending center position may be set by making a part of the connecting spring 13 easy to bend.

(Effects of the Invention) As described above, the present invention is capable of ``utilizing the return pressure of a pressurizing cylinder,'' ``forming contact conformity'' by applying impact pressure, ``promoting self-regeneration of chips,'' and swinging connection using a fulcrum clevis joint. [Oscillating connection by bending leaf springs] and the rapid response to expansion and contraction of the whole as a spring, etc., reduce the pressurizing force and welding current required compared to conventional methods, and achieve highly stable, high-quality welding. In addition, it can be made small and lightweight.

Furthermore, the entire structure can be made into a single piece using plastic matrix composite materials, including arms of various shapes, springs of various strengths, and equalizing mechanisms, allowing for greater flexibility in shape than before. It is also extremely simple and easy to manufacture.
The effect is great.

[Brief explanation of the drawing]

FIG. 1 is a symbolic diagram of the X-type pressure gun of the present invention. 5. Electrode tip 8. Shank 11.12. X-type arm 13 connection spring 21.22 equalize plate spring 23, fixed plate

Claims (1)

[Claims] 1. Resistance welding in which both arms of the X-type gun are connected by a spring strip, and the gun is held by multiple spring strips arranged almost parallel to both arms near the attachment point of the connecting spring strip. Pressurizing device.