JPH02232569A - Prediction of probable disconnection location for very fine wire - Google Patents

Abstract

PURPOSE:To enable detection of a probable disconnection location by using a mechanism of measuring an electric resistance measurement at a part of a very fine wire to perform a local resistance continuously over the entire length thereof moving the wire sequentially without cutting the wire. CONSTITUTION:In the winding of very fine wire 20 with the feeding and stopping thereof repeated intermittently, the wire 20 is fed forward by a specified length (b) with no measurement in the feeding and when the wire is stopped, contactors E, F, G and H are brought into contact with being pinched therewith 20 and a current is applied to a part of length (a) through the current contactors E and F from a constant current power source 1 and then, a voltage at the length part (c) is measured 2 with the voltage contacts G and H arranged between the contactors E and F. A resistance value corresponding to the voltage is compared with a reference resistance value to judge 3 the presence of a probable disconnection location. When the part is normal, the wire 20 is advanced by a length (b) being controlled by a computer 3 to perform the same measurement continuously. When it not, a defective location is displayed or the part involved is cut off 5 and 6. In this manner, the wire is inspected over the entire length thereof thereby upgrading reliability rapidly.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is an ultra-fine electric wire used for magnet wires of stepping motors for watches, etc., and is used to reduce the risk of wire breakage due to resistance heating when energized. Concerning how to predict.

[Prior art] Ultra-thin wires such as magnet wires for watches are extremely thin, and if the wire has uneven spots, the resistivity increases and excessive heat is generated, which could cause the wire to break. .

Once the wire is broken, it loses all its functions and cannot be easily repaired.

There are two possible causes of wire breakage: external and internal.

External causes are assumed to be some kind of strong impact applied from the outside, but this can be prevented by making the winding coating and container more robust.

Internal causes are based on defects that have existed since the wire was originally drawn.

Conventionally, the risk of disconnection in ultra-thin wires with internal defects has been evaluated by cutting off a portion of the wire, using it as a sample, and measuring the electrical resistance.

[Problems to be Solved by the Invention] Electric wires are continuous, so if you cut off the middle part, the wire becomes short and useless. Therefore, one end or both ends of a long electric wire were cut out as a sample, and the electrical resistance of the cut sample was measured.

Even if the electrical resistance value of this sample is appropriate, it does not necessarily mean that the entire wire is of good quality.

For example, inclusions or surface-altered layers that cause a local increase in electrical resistance may exist in the intermediate portion of the wire.

Such wire rods are judged to be good quality by conventional methods, but
In reality, it will have a defect in the middle.

In other words, if defects that cause an increase in electrical resistance are not uniformly distributed over the entire length of the wire, conventional sampling inspections are insufficient.

Moreover, the occurrence of these defects is often stochastic, and it is rare that defects of the same degree exist over the entire length of the wire.

[Means for Solving the Problems] In the present invention, a mechanism that can measure the electrical resistance of only a short part of a series of electric wires is used to move the electric wires one by one to measure the entire length of the electric wire without cutting the wires. Perform local resistance measurements across the area. When a portion with an abnormal resistance value is found, this is detected and a defective portion cutting mechanism or the like is used to take measures such as removing the portion.

[Function] The ultra-fine electric wire is intermittently fed by a predetermined length b, and feeding and stopping are repeated. During feeding, no measurements are taken and the ultra-fine wire is fed forward by a predetermined length b. When the feeding of the ultra-fine wire is stopped, contacts are brought into contact with the ultra-fine wire from above and below, and a constant current I is applied from a constant current power source to a portion of a predetermined length a through the current contact. flows.

A voltage contact placed inside the current contact measures the voltage V(x) over a predetermined length.

From the relationship V(x) = IoR(x), ■. is a constant at constant current, so V(X)
is proportional to the low resistance R(x) of a given length.

It is desirable that this R(x) be constant, but if it is larger than a certain set value Ru, it is determined that there is a risk of wire breakage between the measured length portions a.

If it is normal, the measurement at this point is completed, the ultra-thin wire is sent forward by distance b again, and the same measurements are made continuously.

If there is an abnormality, take measures such as marking or cutting the defective part.

[Embodiment] The following description will be made with reference to the drawings. FIG. 1 is a schematic diagram of a device for predicting a danger point of disconnection of an ultrafine wire according to the present invention.

The ultra-fine electric wire is wound around a reel 7. It is assumed that the starting end of this electric wire is let out, passes through pulleys 8, 9, and 10, and is wound up by a wire winding machine 4.

The pulleys 8 to 10 are for applying appropriate tension to the windings, and these may be increased or decreased.

A long straight section is taken between the pulley 10 and the wire winder 4, and a local electrical resistance measuring mechanism 11 is installed there.

The local electrical resistance measuring mechanism 11 includes a constant current power source 1 and a voltmeter 2.
, computer 3, etc.

The terminals of constant current power supply 1 and voltmeter 2 are contacts E and F1G.
, H are in contact with the ultrafine electrode 1!20.

Current contacts E, F of the constant current power source 1 are separated by a distance a. Voltage contacts G and H of the voltmeter 2 are located in a region sandwiched between E and F.

For example, defective part cutters 5 and 6 are provided at points K and L outside of the current contacts E and F. The distance between the defective part cutting mechanisms 5 and 6 is d, which is used to cut and remove defective parts with abnormally high resistance.

Contacts E, F, G, and H are used to electrically connect the lead wire of a power source or voltmeter to the ultra-fine wire to be measured. Figure 2 shows an enlarged cross-section of an example of the contact. Show the diagram.

A measurement lead wire 2 extending from a constant current power source 1 or a voltmeter 2 is connected to the contact. These contacts include an upper contact block 13, a lower contact block 14, and a spring 2.
Consists of 5 etc.

The upper contact block 13 has an arcuate recess 15 cut out in its lower surface and has a semicircular cross section.

The lower contact block 14 has an arcuate recess 16 cut out on its upper surface and has a semicircular cross section.

The ultra-fine electric wire 20 is sandwiched between the upper and lower circular arc recesses 15 and 16. The radius r of the ultra-fine electric wire 20, the circular arc concave 15,
The arc radius r' of 18 is approximately equal.

A support portion 17 is provided on the side of the upper contact block 13, and a support portion 18 is provided on the side of the lower contact block 14. A spring 25 connects the supports 17 and 18.

The spring 25 elastically suspends the lower contact block 14 from the upper contact block 13.

The upper contact block 13 is fixed by suitable means (not shown).

Therefore, the force U applied to the spring 25 is the weight W of the lower contact block 14 and the force U applied to the block 13 on the ultra-fine electric wire 20.
, 14 and the pressing force F.

U=W+F (1) F is the magnitude of the contact pressure between the ultra-fine '11820 and the block, which must be set carefully. F
If is small, the contact resistance between the ultrafine electric wire 20 and the upper and lower blocks 13 and 14 will increase, resulting in inaccurate measurements.

When F is large, the frictional resistance applied to the ultra-fine electric wire 20 increases,
There is a possibility that the ultra-fine wire may break due to excessive tension.

By selecting F appropriately, it is possible to ensure that the ultra-fine wire does not break and that the contact resistance is approximately 0.

However, safer contacts can also be constructed.

One of them is to use the contact blocks 13 and 14 not as mere fixed blocks but as contact pulleys. By bringing the metal boob into contact with the transfer,
This makes contact with the ultra-fine electric wire. In this way, the pulley rotates, which reduces the frictional resistance that is applied to the ultra-fine wire.

Additionally, safer contacts can be provided as follows.

A mechanism for opening and closing the upper contact block 13 and the lower contact block 14 shown in FIG. 2 by moving them up and down is provided.

The ultra-fine electric wire 20 does not move continuously at a constant speed, but stops when measuring, and is sent forward only when not measuring.

Therefore, the contact block 13,
14 should be opened and closed, and this should be synchronized when feeding and when stopping.

The computer 3 calculates the ultra-fine wire 2 from the measured value of the voltmeter 2.
The local electrical resistance R of 0 is calculated and compared with a preset resistance value to determine whether it is good or bad. Further, the computer 3 controls the wire winding mechanism 4 to intermittently send the ultra-fine wire 20 by a constant length b, and further drives the defective part cutting mechanisms 5 and 6 when a defective part is detected. It has the function of issuing control commands to remove defective parts.

Furthermore, instead of the cutting mechanisms 5 and 6, a marking mechanism may be used to indicate defective locations.

This marking may be made in different colors on the front and rear parts so that, in the case where there are consecutive defective areas, the classification of the defective areas can be easily distinguished.

Furthermore, when a defective part is detected, an alarm can be issued, and the winding reel of the electric wire can be replaced when the defective part is cut and removed, and the generation of slack in the electric wire can be dealt with.

[Effects of the Invention] According to the present invention, the electrical resistance per certain length of the ultra-fine electric wire can be measured continuously over the entire length without leakage, and there is no risk of wire breakage when energizing due to a local increase in electrical resistance. ．． It is possible to predict dangerous parts, and also to remove parts that are at risk of breaking when energized.

Since the test covers the entire length of the wire, the reliability of the test is dramatically improved compared to conventional sampling tests.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a device for predicting a danger point of ultrafine wire breakage according to the present invention. Figure 2 is an enlarged view of the contactor part. l. ．． ．． Constant current power supply 2. ,t pressure gauge3. ．． Computer 4. ．． Wire winding machine 5, 8. ．． Defective part cutting mechanism 7. ．． ．． Lee
Nore 8~lO. , pulley 11. ．． Local electrical resistance measurement mechanism 12. Measurement lead wire 13. ．． ．． Upper contact block 14. ．． ．． Lower contact block 15, IG. 17,18. 20. 2 5. E, F, G, 11 Invention: Arc recess support. Ultra-thin wire spring. Contact child Haga procedural amendment form (voluntary)

Claims (1)

[Claims] (1) A certain length of ultra-fine electric wire is fed out from a reel pre-wound with ultra-fine electric wire or from a wire drawing device that draws material into ultra-fine electric wire, and then wound intermittently by a wire winding machine. , the electric current of the ultra-fine electric wire is measured by alternately repeating the measurement of the local electrical resistance of that part by contacting a current contactor to a part of the electric wire and the feeding of the ultra-fine electric wire by a certain length. A method for predicting the risk of disconnection in an ultra-fine wire, the method comprising measuring resistance over the entire length and predicting locations at risk of disconnection.