SU1731542A1 - Two-electrode head for resistance welding - Google Patents

Abstract

Use: for one-sided or two-sided contact micro-welding in the manufacture of small parts in electronics and instrument making. The welding head contains rods 5 with electrode holders 10 and electrodes 11, swivel arm 3, body 1. In housing 1 between symmetrically positioned guide grooves 4, rotary beam 3 is installed on the axis of rotation 2 with slits on opposite sides. The fingers are inserted into these slots 8

Description

The invention relates to contact welding and can be used for one-sided and two-sided contact welding at two points of sheet parts of various thicknesses and materials, in particular, in the manufacture of small relay parts, and can also be applied in the radio, instrument-making and electronic industries

The known design of a two-electrode head to an electric spot welding machine, comprising a housing in which slots a slider is mounted with the possibility of vertical movement, in its guides are gear racks (rods), kinematically connected with each other by a rotating gear. At the bottom of each toothed rack, horizontal slides with cantilevered electrode holders on them are fixed, which can be moved a certain distance from the axis of the housings to specify the step of welding two points.

The design of the head allows welding the parts simultaneously at two points with an adjustable pitch between them. However, this cumbersome design provides for welding of quite large-sized parts and cannot provide a small distance between the welded points, for example, for welding relay parts (overlays with a core) at a distance between welded points 2 mm.

At the same time, the design of the head has the following disadvantages: uneven pressure equalization due to the presence of rolling in the leveling mechanism, made in the form of a kinematic pair of rack and pinion; the inconsistency of the pitch between the welded points at the minimum welding pitch due to the presence of backlash when a pair of rack and pinion gears is in operation: the head design is not technologically advanced due to the need to have specialized equipment for cutting fine-grained gears and high-precision gear racks; lack of smooth pitch adjustment between two welded points in the size range from 1.5 to 25 + 30 mm due to the design features of the sled; absence of

fixing the plungers, which prevents the fitting of electrodes in a convenient position for stripping the limited field of application, as it is used for only one type of welding machine.

In addition, a well-known head contains plungers mounted in the housing with beveled ends, electrodes mounted on the plungers, and a device for equalizing welding pressure, which

made in the form of rolling bearing pin rigidly mounted on the housing mounted perpendicular to the axis of the plungers, freely entering grooves made on the beveled ends of the plungers, and

interacting with the housing, and rollers mounted on both sides of the rolling bearing with the possibility of interaction with the beveled ends of the plungers. This head has the specified

disadvantages and, in addition, there is no adjustment of the pitch between the two welded points.

Closest to the invention according to its intended purpose and technical essence is a head for contact one-sided two-point welding, containing electrode holders installed in the housing with electrodes and a rotary beam, two

levers that are located between the beam and the body. Each of the levers is installed at one end on the yoke, and the other on the corresponding knife support of the electrode holder. On the opposite side, the arms rest against the knife supports. In this device, the welding force is transmitted in the kinematic chain in two directions: through knife supports, levers, rocker on the electrode holders and through knife supports, levers, electrode holders.

Such a head design significantly lengthens the kinematic chain of force transmission, causing additional losses, since each element of the kinematic chain introduces additional errors. In addition, the design of the device becomes more complicated and its operation 1. The use of knife supports significantly increases the contact pressure at the force transfer points on the levers, which leads to the development of these points of the support and, as a result, to a change in the kinematic accuracy with respect to the ratio of the arms a and b. This affects the accuracy of the alignment of forces due to the dependence of the efforts on the proportion of the arms (a / b),

Moving the fulcrum of the blade part of the electrode holder along the lever also changes the kinematic accuracy in the welding step due to backlash, i.e. eliminates high positioning accuracy of the electrodes and generates this zone on the lever much faster.

Improving the accuracy of force leveling between the electrodes can be achieved, regardless of the welding step, by increasing the arm a, but it is also advisable to increase the arm b. However, this increases the size of the head as a whole, which is unacceptable for the equipment of contact micro-welding used in relay engineering.

The aim of the invention is to enhance the functionality as well as simplify the design.

This goal is achieved by the fact that, in a two-electrode head for contact one-sided or two-sided welding, mainly micro-welds containing a pressure drive, a housing, in guide slots of which electrodes are located with electrodes and in which a rotary beam is installed on the axis, slots are made on the rotary arm the electrode holder is equipped with a finger and consists of two parts of a spring-loaded rod and a fastener. interconnected, with one part of the rod being made with a rectangular cross section, and the other part cylindrical in the rectangular part of the rod a groove is made. in which the finger is rigidly fixed with the possibility of interaction with the slots of the rotary arm, the rectangular parts of the rods are placed in the guide slots of the body, and fastening elements are mounted on the cylindrical part with electrodes.

The head is equipped with adjusting screws which are mounted on the free ends of the rectangular part of the rods, which makes it possible to compensate for the wear of the contact surfaces of the electrodes.

The head is also equipped with spring-loaded locking screws mounted on the housing with the possibility of interaction with the rods, which ensures ease of cleaning the electrodes.

In addition, the head is provided with a mounting plate for the pressure drive, and in the case on the opposite side of the guide grooves along the axis of symmetry, a shaped groove is made, which ensures unification in terms of the application of a number of welding machines to different pressures.

The electrodes are mounted on the ends of the fastening elements and are eccentric, which allows for a minimum distance between the electrodes of up to 1.1-1.5 mm.

Each fastener is equipped with an insulating sleeve into which the cylindrical part of the rod is installed, which ensures the implementation of both one-sided and two-sided welding methods by applying an independent system for applying current to the upper and lower electrodes.

Making the electrode holder in two parts, a spring-loaded rod and a fastener, as well as making the upper part of the rod with a rectangular cross section, and the lower part with a cylindrical one, allow the rotation of the fastening element to smoothly adjust the distance between the electrodes (welding points) in the range 1.5-30 mm, i.e. expand the functionality of the head. Making the electrodes eccentric and installing them at the ends of the fasteners ensures the minimum distance between the electrodes.

Making the upper part of the rod with a rectangular cross section and supplying the body with guide grooves similarly to the cross section avoids turning the rod about the axis, eliminating backlash, preventing distortions and, therefore, achieving high positioning accuracy of the electrodes, which contributes to high repeatability of the assembly of the relay assemblies without additional elements for fixing the electrode holders, which significantly simplifies the design

In addition, the installation of the rotary beam between the symmetrically positioned guide grooves for the rods, which for them, a kind of slide bearing, ensures an equal distribution of the force on the electrodes. The implementation of longitudinal recesses on the lateral planes of the rod allows friction forces between the body and the rods to be reduced, i.e. ensure smooth movement of the rods in the housing, and thus achieve stabilization of the welding process.

Figure 1 presents the head, a general view; figure 2 is the same, top view; fig. 3 - the same, with a different level of the ends of the electrodes; figure 4 - section aa on fig.Z; figure 5 - section bb in figure 4; figure 6 - section bb In fig.Z; 7 - the electrode.

The two-electrode head includes a housing 1 (Figures 1 and 2), in which a pivotally mounted rocker arm 3 is pivotally mounted on the axis 2, at the ends of which the slots are equidistant from the axis 2. The housing 1 is symmetrically arranged with two guide grooves 4 (Figures 2 and 3), of rectangular cross section. Moreover, the grooves 4 are spaced apart to the maximum distance from each other. In the grooves 4, the rods 5 of the electrode holders are installed, which serve as 5 points of support for the rods 5 (figures 1 and 3). The rods 5 are made rectangular and mounted in guide grooves 4 with the possibility of reciprocating movement. On the lateral planes of the rod 5 there are made longitudinal recesses 6 (Fig. 2) to reduce the force of the sliding friction. In the middle part of the rectangular section of the stem 5, transverse slots 7 are made on the outside (Figures 1 and 4). In the central part of the groove 7, the finger 8 (Fig.4) is rigidly mounted along the axis of symmetry of the rod 5, which interacts with the slot surface of the rotary beam 3. From the working (lower) side of the rods 5, their rectangular cross section becomes cylindrical. An insulating slit 9 (Figs. 1, 4 and 5) is mounted on the cylindrical part of each stem 5 (Fig. 5), on which the fastening element 10 of the electrode holder with the electrodes 11 is fixed with the possibility of adjusting the distance between the electrodes. THAT allows you to perform its permutation (rotation around the axis of the rod 5 at a given angle), i.e. vary the distance between the electrodes from 1.5 to 30 mm (Figures 1 and 5). In the fastening element 10 there are two holes 12 and 13c with slotted grooves, the axes of the holes of the fastening elements 10 and the electrode 11 being maximally spaced, a hole 9 is installed in the hole 12, and an electrode 11 is mounted in the hole 13 (Fig.2. 4 and 5) . The fixing of the electrode 11 and the fastening element on the rod 5 is carried out using clamping screws 14 (Fig. 5). The fastening elements 10 are connected to the conductor of the welding machine by flexible copper conductive tires 15.

At the end of the rectangular section of the rods 5, holes are made in which the adjusting screws 16 are installed (Fig. 4). The latter interact with the return springs 17, fixed in the housing 1,

which set the rods 5 to the initial position after the implementation of the welding technological cycle. Adjusting screws 16 allow to compensate for the varying height of the working part of the electrodes.

11, as well as varying the mutual height of the electrodes 11 within small limits in cases where the parts to be welded are not at the same level (Fig. 3). On the opposite side from the guide grooves 4 of the body 1 (FIG. 2), a groove 18c is provided with a shaped surface for accommodating and securing the power shaft of the welding machine (FIGS. 2 and 3).

From the side of the shaped groove 18 case

1, a head fastening plate 19 is placed, which also has a semi-cylindrical groove for clamping the power rod of the welding machine with the head housing 1,

Hole formed between the body

The strap 19 is fastened in such a way that, without changing their design, allows the head to be mounted on power rods of various machines up to $ 20 mm.

In the upper part of the housing 1, locking screws 20 (FIGS. 1 and 3) with release springs 21 are installed on the side planes. With the help of fixing screws -20, the rods 5 with fastening elements are fixed in

any position convenient for cleaning the electrodes 11.

The release springs 21 of the fixing screws 20 serve to prevent them from self-unscrewing during the operation of the welding machine.

The body of the two-electrode head is closed by a cover 22.

The welding head works as follows.

Before welding under the action of F.S. from the rod 5 of the welding machine, the head is lowered until the electrodes touch

I1c details. This force is evenly distributed between the rods 5 of the head, which

is provided by the equality of the shoulders of the swivel arm 3 from the axis 2 in the housing 1 to the axis of symmetry of the rod 5. Through the fingers 8, a force is transmitted to the rods 5 with fasteners 10 and, accordingly, to the electrodes 11. which is equal to the total force F.

In the case where the parts under the electrodes 11 are not located at the same level (FIG. 3). when the welding head moves down, the upper part touches one of the two electrodes 11 and the process of applying a part of force to the part begins. In this case, the force from this electrode 11 is transmitted to the rod 5 of the corresponding fastening element 10 and through the stationary pin 8 of the rod 5, interacting with the swivel arm 3, is transmitted to the second rod 5, and through it to the fastening element 10, thereby ensuring the force leveling. After the end of the welding cycle, due to the fact that the force from the return springs 17 (FIG. 4) is applied at the opposite ends of the rod 5, the swivel arm 3 returns the rods 5 to the initial initial position.

In the process of self-installation of the rods 5, their mutual movement is not constrained by the friction sliding force due to its insignificant value as compared with the force FЈ applied to the welding head directly to the electrodes 11, which ensures accurate pressure equalization on the electrodes 11. The force FJ reaches values up to 35 kgf, and the friction sliding force of the rod 5 does not exceed 10-15 g, which is only 0.04% (for welding small-sized parts of the relay);

Thereby, the identity of the thermal-deformation cycles of welding around the weld points and, as a consequence, an increase in the stabilization of the welding process is achieved. The design of the proposed head ensures sufficient precision of the equalization of forces at equal height and different height levels of the working surfaces of the electrodes, which makes it possible to obtain a stable quality of welding parts of equal and unequal thicknesses.

The proposed solution in comparison with the prototype has the following advantages.

The functionality is enhanced by installing fasteners on the cylindrical part of the rods, with the possibility of their smooth rearrangement.

The positioning accuracy of the electrodes increases, contributing to the stabilization of the welding process, by making the upper part of the rod with a rectangular cross-section, supplying the body with guide grooves, which excludes rotation of the rod and backlash between the rod and the body.

In addition, such a constructive implementation of the body and rods allows for the transfer of force along one chain: a rotary beam - finger - electrode-5 holder - electrode.

A uniform distribution of the force on the electrodes is ensured, contributing to the stabilization of the welding process, by installing a rotary beam between

0 guide grooves and longitudinal recesses on the side planes of the rod.

The wear of the contact surfaces of the electrodes is compensated for by providing

5 heads with adjusting screws and installing them on the free ends of the rods.

The convenience of stripping electrodes is improved by providing the head with spring-loaded fixing screws and

0 installing them on the body with the ability to interact with the rods.

Unification is ensured by supplying the head with a pressure actuator mounting plate and

5 opposite side of the guide grooves along the symmetry axis of the shaped groove.

The minimum distance between the electrodes (up to 1.1-1.5 mm), i.e.

0 welding points, due to the installation of electrodes on the ends of fasteners and making them eccentric.

In addition, both single-sided and double-sided 5 welding methods are implemented by installing fasteners on the cylindrical part of the rod using an insulating sleeve.

Electrode life increases

0 by making them straight-sided with a cylindrical mounting part and installing them in the female slot of the fastener.

Claims (6)

The proposed technical solution can be used for making welded assemblies of miniature relays. Claim 1. A two-electrode head for resistance welding, mainly micro-welding, comprising a pressure actuator, a housing, in the guide grooves of which electrode holders with electrodes are located and in which a rotary beam is mounted on the axis, characterized in that 5 the goal of extending the functionality by providing both one-sided and two-sided welding, as well as simplifying the design, slotted on the rotary beam, each electric holder is equipped with a finger and made of two parts: a spring-loaded rod and a fastener interconnected, with one part of the rod made with a rectangular cross section and the other cylindrical, in the rectangular part of the rod there is a groove in which a finger is rigidly fixed with the possibility of interacting with the slotted The rotary beam, the rectangular parts of the rods are placed in the guide grooves of the body, and fastening elements on which the electrodes are fixed on the cylindrical part of the rods. 2. The head according to claim 1, that is, so that, in order to compensate for the wear of the contact surfaces of the electrode, it is equipped with adjusting screws, which are mounted on the free ends of the rods. 3. The head according to claims 1 and 2 is distinguished, in particular, in order to provide ease of cleaning the electrodes, it is equipped with spring-loaded locking screws mounted on the housing with the ability to interact with the rods. 4. The head according to claims 1 to 3, characterized in that, in order to ensure unification, it is provided with a mounting plate for the pressure drive, and in the case on the opposite side of the guide grooves along the axis of symmetry, a shaped groove is made. 5. Head according to claims 1-4, characterized in that, in order to ensure a minimum distance between the electrodes up to 1.1-1.5 mm. The electrodes are eccentrically mounted on the ends of the fasteners. 6.Header on PP. 1-5, characterized in that, in order to ensure the performance of double-sided welding, it is provided with an insulating sleeve installed in the fastening element. 20 2 / & 5 & ig / f Ј0  tfig five Phage 6 / L 22 g V- A. 5 FIG. 7