RU2487788C2 - Solder wire and method of its production, hermetic connector and method of its production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of high-precision instruments and electronic components. Solder wire composed of single-row helical spiral with the number of turns wherein total volume of solder exceeds that of annular clearance for forming of soldered seam between parts, spiral ID is sized to allow coil stringing on one of parts being soldered together. In compliance with proposed method, turns are cut in radial direction to mirror axis of turns by cutting length with several turns from spiral. Note here that volume of cut turns corresponds to amount of solder sufficient for making seam between parts being soldered together. Hermetic connector has inner isolator that allows stringing, before seam formation, of solder spiral thereon. Note here that outer and inner isolators make two different-diameter annular clearances.

EFFECT: lower costs, higher reliability and quality in operation in severe conditions.

6 cl, 11 dwg

Description

The group of inventions relates to the manufacture of precision instruments and electronic products. They can be used, for example, to obtain a vacuum-tight and heat-resistant junction between miniature parts.

Known by the application of Japan No. 60-38080, (IPC B23K 35/40; publ. In o / b "Industrial Property" ("Listes", from 06/18/1985), the design of the solder wire contains a turn.

The disadvantage of this design of wire solder is that the coil is made open. When heated during soldering, an open coil has the ability to deform, move away from the first part it covers and come into contact with the surface of the second part. In this case, when melting the solder, which includes active components, will begin to spread over the surfaces of the second part and only after that it will begin to flow into the annular gap between the parts to be joined. As a result, a significant portion of the solder will not fall into the annular gap. In the manufacture of connectors with several conductors, there is a high probability of their closure with each other due to the spreading of solder on the surface, that is, getting defective.

This device is an analog.

Known by Japanese application No. 60-38080 (IPC V23K 35/40; published in the industrial property "Listes", 06/18/1985) a method of manufacturing a solder structure involves forming a single-row helical spiral by winding wire solder on the mandrel, removing the wound turns from the mandrel and cutting them.

The disadvantage of this method is to obtain an open loop, as well as the complexity of its formation, since:

- in the manufacture of the design of solder, in addition to the above steps, it is necessary to fix the turns of wire on the mandrel by wrapping them with foil, and then conducting heat treatment;

- cutting spiral coils is carried out in the longitudinal direction. If we take into account the fact that in the manufacture of, for example, a miniature connector for soldering its parts, the solder is made, for example, from a wire with a diameter of 0.05 ... 0.1 mm in the form of a coil with an inner diameter equal to or less than 0.8 mm, then cutting turns in the indicated direction of the solder wire is a difficult task. As a result, the coil turns open (wire solder design).

This method is the closest analogue.

Known by the patent of the Russian Federation No. 2322718 (IPC НВВ 17/26; published in BI No. 11 of 04/20/2008, a sealed connector containing a conductor and a ceramic insulator, a junction of solder material is formed between the conductor and the insulator.

The disadvantage of this design is that during the connection of the insulator with the conductor there is a high probability of the spreading of the molten solder, which includes active components, on the end surface of the insulator. If there is a metal housing in the connector design, a short circuit may occur between it and the conductor.

Known by AC No. 555445 (IPC НВВ 17/26; published in BI No. 15 of 04.25.1977) a hermetic connector containing a composite insulator, at least one inner insulator of which is equipped with a conductor made in the form of a metallized coating applied to its surface A junction of solder material is formed between the outer and inner insulators.

In the considered connector of the internal insulators, three are made.

The disadvantages of this connector are:

- the possibility of reducing the reliability of electrical conductivity due to the fact that the conductor, made in the form of a metallized coating, has a porous structure;

- a high probability of short circuit between the contacts due to the spreading of the molten solder during soldering on the surface of the external insulator;

- the need for junctions between the outer and inner insulators at both ends of the outer insulator.

This device is the closest analogue.

Known according to the patent of the Russian Federation No. 2336980 (IPC V23K 01/00; published in Bulletin No. 30 dated October 27, 2008), a method for manufacturing an airtight connector includes placing solder on the parts to be joined, heating it to the melting temperature, filling the annular gap by capillary flow by molten solder between these parts, subsequent cooling of the solder.

The disadvantage of this method is the difficulty of its implementation when connecting miniature parts. This is explained by:

- the formation of a coil, the diameter of which is equal to tens of microns, is carried out manually from solder material made in the form of a strip of foil, the thickness of which is equal to units of microns;

- the installation of such a coil between the joined surfaces of the parts in an annular gap, the value of which is also equal to units of microns, is an almost impossible task.

This method is the closest analogue.

The tasks of the group of inventions are:

- reducing the cost of manufacturing the design of solder;

- reduction in the number of defective connectors among manufactured products;

- increase the reliability of the connector when operating in hard heating-cooling modes;

The technical result achieved by using the present inventions is that they provided:

- improving the reliability of electrical conductivity;

- holding the solder during its heating near the surface of one part above the annular gap formed by the joined surfaces of the two parts;

- limiting the area of possible spreading of the molten solder by the size of an additionally performed annular gap between the joined surfaces of the parts;

- reducing the dimensions of the connector;

- reducing the number of operations required for the manufacture of the solder structure;

- the possibility of swelling of the molten solder material along the first part to the annular gap between the joined surfaces of the parts and filling it without significant spreading of the solder on the outer surface of the second part;

- in case of detection of marriage resulting from the spreading of molten solder along the end surfaces of the insulator, the possibility of correction, regardless of the number of contacts.

The above technical result is achieved by the fact that:

- in the design of wire solder formed in the form of a single-row helical spiral made with the number of turns, the total volume of solder, in which exceeds the volume of the annular gap intended for the formation of a junction between the joined parts, the inner diameter of the spiral is made with a size that ensures its stringing on one of the connected interference fit parts;

- in a method of manufacturing a design of wire solder, including the formation of a single-row helical spiral by winding the wire solder on the mandrel, removing the wound turns from the mandrel and cutting them, cutting the turns is performed in the radial direction to the axis of symmetry of the turns, cutting off a piece with several turns from a single-row spiral spiral. Moreover, the total volume of cut turns corresponds to the amount of wire solder sufficient to obtain a junction between the parts to be joined;

- in a sealed connector containing a composite insulator, at least one inner insulator of which is equipped with a conductor made in the form of a metallized coating deposited on its surface, a junction of solder material is formed between the outer and inner insulators. The internal insulator is made with the possibility of stringing with an interference fit on it a solder structure formed in the form of a single-row helical spiral. In this case, the outer and inner insulators formed two annular gaps with different sizes, the first gap was filled by solder with an active component by capillary flow, and the second gap, the size of which excludes the possibility of its capillary flow, is filled at least partially. The inner insulator can be connected to the outer insulator in such a way that its end is located in a common plane with the end of the outer insulator or is located at a distance from the plane passing through the end of the outer insulator, while the size of the removal does not exceed two outer diameters of the inner insulator. A metallized coating can be applied to both ends of the inner insulator, while the junction between the outer and inner insulators is electrically connected to both parts of the metallized coating;

- in a method for manufacturing a sealed connector, including placing solder on the conductor and the external insulator, heating it to the melting temperature, filling the annular gap between the conductor and the external insulator by capillary flow, subsequent cooling of the solder, wire solder made in the form of a single-row helical spiral, string with an interference fit on the conductor. The conductor is passed through the outer insulator so that the coils of the spiral are located at least partially in the recess made at one end of the hole in the outer insulator.

The design of the solder in the form of a single-row helical spiral made it possible to hold the solder when it is heated near the part on which the spiral is strung. The execution of the spiral with the number of turns, the total volume of solder in which is sufficient to make a junction between the parts to be joined, ensured the filling of the annular gap between the parts to be joined by capillary flow of the solder in the molten state. In this case, the volume of the turns of the solder spiral is increased by an amount that partially does not fall into this gap. The implementation of the inner diameter of the spiral with a size that ensures its stringing on one of the connected parts with an interference fit, ensures that the solder is kept near the surface of this part until it is melted. The proposed new set of features provided a new result, namely, reducing the likelihood of molten solder spreading over the end surface of the external insulator connected by active soldering to the internal insulator.

Radial cutting of a spiral helix simplified the process of cutting wire irrespective of the size of the spiral. Cutting off several turns from it made it possible to accurately dispense the volume of solder consumed during soldering. Knowing the diameter of the wire and the coil of the spiral, it is easy to determine its volume and select the required amount of solder to be consumed. The proposed new set of features has provided a new result, namely, a simplification of the method of manufacturing the design of the solder and reducing its cost.

The execution of the inner insulator in such a way that its end face is located in a common plane with the end face of the outer insulator or is located at a distance from the plane passing through the end face of the outer insulator has provided the possibility of making miniature connectors in which the inner insulator may have, for example, a diameter of less than one and a half millimeters. The limitation of the deviation of the end face of the inner insulator from the plane passing through the end face of the outer insulator to the two outer diameters of the inner insulator eliminated the possibility of breakage of the ends of the inner insulator made, for example, of ceramic, prone to chips. When the inner insulator protrudes beyond the end of the outer insulator to a distance limited by a predetermined size, the ends of the inner insulator have sufficient strength. The formation between the outer and inner insulators of two annular gaps with different sizes excluded the possibility of spreading molten solder on the surface of the end face of the outer insulator during the implementation of the vacuum-tight connection between the insulators. Filling the first gap by capillary flow with solder with an active component made it possible to obtain a vacuum-tight connection between the inner and outer insulators with a single seam. At least partial filling of the second gap, the size of which eliminates the possibility of its capillary flow by solder, ensured that the solder was kept near the internal insulator during filling of the first gap with solder. This eliminates the possibility of spreading solder on the surface of the end face of the external insulator. In this case, the conductor, made in the form of a metallized coating, can have various options. In the first embodiment, the coating is applied to both ends and the cylindrical surface of the inner insulator, and in the second embodiment, only to both ends. In both versions, the solder filling both ring gaps performs the additional function of an electrical conductor, the reliability of which is higher than that of a coating having a loose structure. A new set of features has provided a new result, which is to reduce the number of defective connectors among manufactured products.

Stringing wire solder, made in the form of a single-row helical spiral, with an interference fit on the conductor, ensured that the molten solder flows out over its surface to the annular gap between the connected parts. Passing the conductor through the insulator so that the coils of the spiral were located at least partially in the recess made at one end of the hole in the insulator did not allow the part of the molten solder that did not fall into the first annular gap to fill at least partially the second annular gap between the conductor and the insulator. As a result, the probability of molten solder spreading over the end surface of the external insulator is excluded. The proposed new set of features provided a new result, namely, a decrease in marriage among manufactured connectors.

The group of inventions is illustrated by drawings. Figure 1 shows the design of wire solder; figure 2 - wire solder wound on a mandrel; figure 3 - billet design solder; figure 4 - design of a sealed connector with one contact; figure 5 - design of a ceramic insulator; figure 6 is a design variant of a ceramic insulator; Fig.7 is a design variant of a ceramic insulator; on Fig - design of a sealed connector with two contacts; figure 9 - connectable parts of the sealed connector mounted on them solder (option 1); figure 10 - connected parts of a sealed connector mounted on them solder (option 2); figure 11 - design of solder and miniature sealed connector, depicted in the estimated scale (for comparison, an image of a match); where 1 is wire solder; 2 - mandrel; 3 - external insulator; 4 and 8 - internal insulators; 5 and 9 - conductors; 6 - deepening; 7 - hole; d _vn is the internal diameter of the spiral; N ₁ , N ₂ , M ₁ , M ₂ , - annular gaps; T ₁ , T ₂ , T ₃ , T ₄ - deviations of the ends of the conductor from the ends of the external insulator; S is the distance from the lower coil of the solder spiral to the annular gap of a smaller size;

Q is the end surface.

The design of the wire solder 1 contains a coil.

The wire solder 1 is formed in the form of a single-row helical spiral (Fig. 1). The spiral is made with the number of turns, the total volume of wire solder 1 in which is sufficient to perform a junction between the connected parts. The inner diameter d _ext helix formed with a size ensuring its threading on one of the parts to be joined with an interference fit.

The wire solder 1 may have a cross section, for example, round, square and rectangular in shape.

A method of manufacturing a design of wire solder 1 includes the following.

The formation of a single-row helical spiral by winding wire solder on the mandrel 2 (figure 2), removing the wound turns from the mandrel and cutting them.

The cutting of the turns of wire solder 1 (Fig. 3) is performed in a radial direction to the axis of symmetry of the turns, cutting a piece with several turns from the workpiece of the solder structure (Fig. 1), while the total volume of cut turns corresponds to the amount of solder material sufficient to obtain a junction between two connectable parts. The number of pieces cut from the workpiece of the solder structure corresponds to the number of soldered joints to be performed.

The connector (figure 4) contains a composite ceramic insulator, which consists of an external insulator 3 and an internal insulator 4. The conductor 5 is made in the form of a metallized coating deposited on the surface of the internal insulator 4. A junction of solder material is formed between the external insulator 3 and the internal insulator 4 one.

The outer and inner insulators (3 and 4, respectively) can be made, for example, of corundum (VK 94-1) or forsterite (VF 52.42.1) ceramics. The conductor 5, made in the form of an electrically conductive layer, can be deposited on the surface of the inner insulator 4, for example, by plasma spraying of metal or by burning metallization paste.

The connection of ceramic insulators 3 and 4 can be obtained, for example, by a multistage method. In this case, at the inner insulator 4, a metallized coating is applied to both ends and the cylindrical surface.

The ceramic-metal compound can also be obtained by a single-step method. In this case, the mating surfaces of the connected insulators 3 and 4 can be made not metallized. A metallized coating is applied only to both ends of the inner insulator 4 (not shown in FIG.).

In this case, the execution of the junction from the solder material 1 with the active component, which may be, for example, titanium or zirconium, ensured high wetting of the ceramic surfaces.

In both cases, the execution of the conductor junction material of solder 1 performs the additional function of an electrically conductive layer between both metallized ends of the inner insulator 4.

The outer and inner insulators formed two annular gaps with different sizes M ₁ and N ₁ (M ₁ <N ₁ ). To do this, at one of the ends of the external insulator 3 there is a recess 6 located around the hole 7 (in Fig. 5, the internal insulator 4, the conductor 5 and the junction from the solder material 1 are not conventionally shown). The inner insulator 4 is made in the form of a cylindrical rod. The first gap M ₁ is completely filled by the capillary flow of molten solder 1. Filling of clearance M ₁ 1 volume of molten solder effected by gap size for example equal to one micron. The second gap N _{1 is} made with a size that excludes the possibility of filling it by capillary flow of molten solder 1. The molten solder 1, not falling into the gap M ₁ , filled this gap, at least partially. Reliability of the soldered connection between the external and internal insulators (3 and 4, respectively) is achieved with a high degree of tightness.

The internal insulator 4 can be made in such a way that:

- its ends are located in a common plane with the ends of the external insulator 3 (figure 4);

- its ends are recessed relative to the ends of the external insulator 3 (Fig.6);

- its ends protrude relative to the ends of the external insulator 3 (Fig.7);

- one of its ends is recessed relative to the first end of the outer insulator 3, and the second protrudes relative to the second end of the outer insulator 3 (not shown in Fig.).

The deviation sizes T ₁ ... T _{4 of the} ends of the conductor 5 from the ends of the outer insulator 3 do not exceed two outer diameters of the inner insulator 4.

In the connector, internal insulators with conductors of more than one, for example, two, can be made (for example, two (Fig. 8). In this case, the second inner insulator 8 with the conductor 9 is identical to the inner insulator 4 with the conductor 5. In this case, a second hole is made in the outer insulator, which is identical to the hole 7 shown in Fig. 5. Between the outer and inner 8 insulators formed junctions of solder 1.

If one or several internal insulators (for example, 4 and 8) are made with conductors in the same external insulator when a part of the molten material of solder 1 gets on the ends of the external insulator and shorts the conductors whose ends are recessed relative to the ends of the external insulator, it is possible to fix the marriage. For this, the solder that has fallen on the ends of the outer conductor is cut off during additional processing of the outer insulator.

A method of manufacturing a sealed connector includes the following.

Placement on the connected parts, for example, on the outer insulator 3 and the inner insulator 4 (figure 4) of solder 1 (figure 1), heating it to the melting temperature. Filling, by capillary flow with molten solder, an annular gap M ₁ between these parts. Subsequent cooling of the solder.

When soldering, you can use solder with an active component, for example, titanium or zirconium.

The wire solder, made in the form of a single-row helical spiral, is strung with an interference fit on the inner insulator 4, which is then passed through the hole 7 (Fig. 5) in the outer ceramic insulator 3 so that the coils of the spiral are located at least partially in the recess 6 formed on one end of the openings in the outer insulator 3. in this case, the inner insulator 4 and the conductor 5 spiral turns of the solder material 1 forms with the walls of the recess 6 further annular gap larger N ₁ (4), which impeding its filling by capillary flow of molten solder 1. The distance S (Figure 9) from the lower spiral coil 1 to solder the annular gap smaller size is equal to zero or greater than zero.

During filling by capillary flow with molten solder 1 of the annular gap M _{1, a} part of it, when swelling along the inner insulator, remains in the annular gap N ₁ , which prevents the solder 1 from spreading over the end surface Q of the outer insulator 3.

The above method can be soldered (figure 10) of a ceramic external insulator with a conductor made in the form of a metal pin. A conductor such as a body of revolution made, for example, from Kovar (alloy 29NK), is preferably made with a blind hole. As a result (RF patent No. 2322718), the conductor has flexibility and the ability to deform when performing a junction. This prevents cracking of the outer insulator due to the reduction of stresses caused by the difference in the temperature coefficients of the linear expansion of the materials being joined. The implementation of the solder in the form of a spiral, and in the outer insulator of the annular gaps M ₂ and N ₂ provides the above technical effect.

Example. When soldering an external insulator with a conductor made in the form of a metal pin, the number of turns of the spiral from the solder material 1 (Fig. 1) will be determined by the volume of the annular gap M ₂ between the surfaces of these parts to be connected and the volume of the solder material 1 consumed during its spreading soldering in the annular gap N ₂ . The amount of material of wire solder 1, spreading during soldering, is determined experimentally when testing the manufacturing technology of the connector.

The heating of the solder 1 and its cooling can be carried out, for example, by a known method (RF patent No. 2278007). This method is implemented on common electrovacuum thermal equipment in a vacuum of 1 · 10 ^-3 -1 · 10 ^-4 mm Hg An alloy of a eutectic composition copper-titanium with the addition of low-melting metals tin and indium is used as solder. Heating is carried out until a copper-titanium eutectic is formed and held at this temperature for at least 20 minutes.

Upon the mutual dissolution of titanium, tin, and indium in copper, an active alloy is obtained, which provides wetting of the brazed materials at the melting temperature of the active alloy. Cooling is carried out to a temperature of 700 ... 750 ° with exposure at this temperature for at least 20 minutes. Further cooling is carried out to room temperature.

The company carried out work on the production of prototypes of miniature sealed connectors and worked out methods of winding microcoils, which are designed to manufacture the design of wire solder (figure 1).

Using this group of inventions allowed to obtain:

- holding the solder during its heating near the surface of one part above the annular gap formed by the joined surfaces of the two parts;

- limiting the area of possible spreading of the molten solder by the size of an additionally performed annular gap between the joined surfaces of the parts;

- reducing the dimensions of the connector;

- reducing the number of operations required for the manufacture of the solder structure;

- the possibility of swelling of the molten solder material along the first part to the annular gap between the joined surfaces of the parts and filling it without significant spreading of the solder on the outer surface of the second part;

- in case of detection of marriage resulting from the spreading of molten solder along the end surfaces of the insulator, the possibility of correction, regardless of the number of contacts.

Claims (6)

1. The design of the wire solder, formed in the form of a single-row helical spiral, made with the number of turns, the total volume of solder in which exceeds the volume of the annular gap intended to form a junction between the joined parts, the inner diameter of the spiral is made with a size that ensures its stringing on one of the connected interference fit parts. 2. A method of manufacturing a design of solder, including the formation of a single-row helical spiral by winding the wire solder on the mandrel, removing the wound turns from the mandrel and cutting them, characterized in that the cutting of the turns is performed in the radial direction to the axis of symmetry of the turns, cutting off a piece of several turns, while the total volume of cut turns corresponds to the amount of solder material sufficient to obtain a junction between the parts to be joined. 3. A sealed connector containing a composite insulator, at least one inner insulator of which is provided with a conductor made in the form of a metallized coating deposited on the surface of the inner insulator, a junction of solder material is formed between the outer and inner insulators, characterized in that the inner insulator is made with the possibility of the formation of a solder with an interference fit on it of a solder structure formed in the form of a single-row helical spiral, while the outer and inner insulators form two annular gaps with different sizes, the first gap is filled by capillary flow with solder with an active component, and the second gap, the size of which excludes the possibility of its capillary flow, is filled at least partially. 4. The hermetic connector according to claim 3, characterized in that the inner insulator is connected to the outer insulator in such a way that its end is located in a common plane with the end of the outer insulator or is located at a distance from the plane passing through the end of the outer insulator, while the size removal does not exceed two outer diameters of the inner insulator. 5. The sealed connector according to claim 3, characterized in that the metallized coating is applied only to both ends of the inner insulator, while the junction between the outer and inner insulators is electrically connected to both parts of the metallized coating. 6. A method of manufacturing a sealed connector, including placing solder on the parts to be joined, heating it to a melting point, filling the annular gap between the conductor and the external insulator by capillary flow with molten solder, subsequent cooling of the solder, characterized in that the wire solder made in the form of a single-row screw spirals, strung with an interference fit on the conductor, the conductor is passed through the external insulator so that the spiral coils are located at least partially in the recess and made at one end of the hole in the insulator.

Images