SU924766A1 - Method of manufacturing precision wire-wound encapsulated resistors - Google Patents

Description

(54) METHOD FOR PREPARING PRECISION HERMETHIZED WIRE RESISTORS

I

The invention relates to electrical engineering, preferably, to methods for manufacturing high-precision encapsulated resistors, the winding of which is made of thin conductors, in particular, of microwires in glass insulation.

A known method of manufacturing precision wire resistors, which involves manufacturing. resistors from two windings: main and additional, compensating non-reversible changes of resistance of resistors during thermal stabilization 1.

In the manufacture of resistors according to this method and the subsequent pouring with a sealant (compound), an irreversible change in resistance from the effects of the gritty material often negates the advantages of the known method. Therefore, progressive, easily automated sealing methods have to be replaced

2

less technological manual sealing in ceramic enclosures. It also does not improve reliability due to increased winding overheating.

The closest to the present invention is a method for manufacturing precision sealing wire resistors, including the operations of winding the main and additional windings, their thermal stabilization and sealing of G2.

The disadvantage of this method is the formation of non-conductive elements as a result of pouring a sealant and subsequent polymerization of elements with a winding of thin wires. As a result, the entire multi-element resistor is sent to the fault. In addition, casting of resistive elements with a compound causes subsequent changes in resistance due to aging of the compound and its effect on the winding for a long time after the resistor is manufactured. This phenomenon prevents the increase in the accuracy of wire resistors to values of 0.001–0.005.

The purpose of the invention is to increase the yield of products and increase the accuracy of the nominal resistors.

The goal is achieved by the fact that the method of manufacturing precision sealed wire resistors, including winding the main and additional windings, their thermal stabilization and sealing, thermal stabilizing the main winding is performed after sealing it, and the additional winding is made after thermal stabilizing the main winding.

In the process of thermal stabilization, a series of physical and chemical processes occur, leading to irreversible changes in resistance, and one of these processes is the oxidation of uncoated sections of wire and wire contacts with current leads. With a large wire length on the resistor (from units to hundreds of meters), the magnitude and number of insulation defects vary greatly from resistor to resistor depending on the quality of the wire, tension fluctuations during winding and other reasons. The result of all this is a large dispersion of an irreversible change in the resistance of the dK to different segments taken from one coil (from one batch) of the wire; For a microwire in glass insulation, the QD can range from 0.01 to O. The common resistors from one coil, which negates all the advantages outlined earlier.

The method includes thermal stabilization of the sealed winding i. winding, the wire of which is protected from oxidation, the magnitude of the irreversible change becomes much more stable, its dispersion averages 0.5, therefore, the previously mentioned increase in the accuracy of the finished resistors to 0.001-0.005% becomes possible.

The method is carried out as follows.

A cut is measured from the coil of the wire intended for the resistor, and wound onto the frame, then silicon is sealed with an organic sealant (for example, elastosil 11-01).

After the polymerization of the compound, the sample is stabilized in the mode of: 250 ° C for 1 h, then 150 ° C for b h (the thermal stabilization mode is optimal for this metal wire), after thermal stabilization as a result of

the measurement determines the magnitude of the irreversible change in sample resistance (0.1-0.5). Then, a batch of resistors is made from the wire of this coil, the main winding of which is wound by a magnitude of resistance less than nominal (since the irreversible change is positive) by the amount of correction. Next, a sealing is performed.

When manufacturing a multi-element resistor, the individual elements are assembled into an electrically connected circuit, with some resistors

Additional winding is a segment of a wire of large diameter (0.5-1 mm) and serves as a mounting element in the assembly of the circuit. The assembled circuit is filled with a compound in a special package. The accuracy of such a multi-element resistor reaches 0.001%, and the instability after exposure to temperature changes (-60) (+100) С does not exceed 0.01%

The technical effect of the proposed method is that it allows to increase the accuracy of manufacturing sealed wire resistors, increase their reliability, since the working temperature is always lower than the temperature of stabilization, to simplify the process of manufacturing multi-element resistors.

The annual economic effect will be more than 200 thousand rubles. This amount is calculated on the annual release of 800 thousand resistors with an accuracy of 0.01%.

Claims (2)

Invention Formula A method of manufacturing precision sealed wire resistors, including the operations of winding the main and additional windings, their thermal stabilization and sealing, characterized in that, in order to increase the output year 532k7b66 products and improve the accuracy of 5 C nomi- Sources of information Nala resistors, the operation of the thermostat-taken into account in the examination of the bilization of the main winding of the wire 1. USSR author's certificate d t after its sealing, and dopol No., cl. H 01 C T7 / 00, 13.0.70. the winding is made after 5 2. US Patent No. thermal stabilization of the main winding.kl. H 01 C 17/00, 2. 10.1967.