EP0499775B1 - Process and device for lubrification of a wire - Google Patents

Abstract

A process for lubricating a wire by coating the wire with a solid or liquid lubricant is characterised in that the wire (1) is passed through at least one loop (5), resting against the wire, of at least one absorbent strand (2) of material impregnated with the lubricant and the strand of material is advanced at an essentially constant rate which is lower than the feed rate of the wire. A device for carrying out the process has a push- or pull-type feed device for a wire and a push- or pull-type feed device for at least one strand of material wound around the wire.

Description

It is known that wires, such as electro-insulated winding wires for the manufacture of electrical engineering products, must have good meltability so that they can be positioned easily and precisely in the manufacture of windings. In addition, the sliding properties of the wire are intended to protect the electrical insulation layer during processing.

Various methods are known for lubricating wires. Predominantly, paraffins are used as lubricants, which are applied in the form of solutions in petrol or other organic solvents via a felt to the mostly warm wire as a coating. The solvent is evaporated, a thin layer of paraffin remaining on the wire surface (see, for example, US Pat. No. 4,545,323). These blending methods use 1/2 to 1% paraffin solutions, so that the lubrication causes high solvent losses and thus economic losses and at the same time a considerable pollution of the air.

Another known method uses aqueous emulsions or dispersions of the paraffins instead of solutions of the paraffins in petrol or other organic solvents. This avoids the emission of organic solvents, but metering the emulsion with a wick or felt is difficult. Such a method is therefore not suitable if, as is often desired, very precisely defined amounts of paraffin have to be applied to the wire surface. Otherwise, the use of aqueous emulsions requires an additional drying process.

All previously known methods in which the lubricant is applied to the wire by means of felt also have the additional disadvantage that the felt is rubbed off after a long period of operation of the wires, it often not being recognized that, due to this abrasion, the lubricant is applied only on one side or incomplete.

The object on which the invention is based was now to avoid the disadvantages of the known methods for lubricating wires, in particular to obtain a method which is as simple and reliable as possible and to thereby avoid solvent emissions.

The process according to the invention for making a wire lubricant by coating the wire with a solid or liquid lubricant is characterized in that the wire is passed through at least one loop of at least one absorbent strand of material soaked in the lubricant, and the material strand is essentially constant Speed that is slower than the wire feed speed advances.

If we are talking about a feed speed of the wire, this can be generated by pushing or usually by toe the wire.

The method has the additional advantage that the average coefficient of friction and its dispersion is lower than when using a solution of the lubricant.

Any material that can be looped around the wire and has sufficient strength during the feed so that it does not tear off can be used as an absorbent strand of material. This strand of material is expediently a thread or thread or thread of some other kind at least once, usually several times, around the wire. Pure cotton threads are particularly suitable because they are particularly absorbent, but any other absorbent textile materials can also be used. The thread or twine thickness is preferably such that it allows a good controllable preferred speed, but still gives sufficient tear resistance. Yarns or threads with a weight of 30 to 300 g / km are preferred.

In general, a strand of material, such as a thread or a twine, which is wrapped around the wire will be used in the process according to the invention, but two or more such strands of material can also be wrapped around the wire in succession if a denser filling of the wire with the loops is desired .

Liquid or solid substances with sliding properties can be considered as lubricants, although solid lubricants at ambient temperature are preferred, since they give a better sliding effect. The usual lubricants are paraffins, but oils, fats and waxes can also be used. To improve the wetting of the wire surface, all of these lubricants can also contain surfactants, such as and in particular the known fluorine-containing wetting agents. For example, a suitable lubricant can consist of 98 parts by weight of a paraffin with a melting range of 50 to 54 ° C and 2 parts by weight of a commercially available fluorine-containing wetting agent.

In the process according to the invention, it is particularly advantageous that waxes can also be used as lubricants which, because of their high melting point and their tendency to crystallize, cannot be processed into solutions which are stable in the cold. Such waxes, such as bees or carnauba wax, improve the lubricity under certain rubbing stresses more than the relatively low-melting paraffins.

The amount of impregnation of the absorbent strand of material can be varied as desired. For example, the yarn or the lubricant can contain an amount of approximately 100% of its own weight as an impregnation. The amount of lubricant in the absorbent strand of material is a means of regulating the amount of lubricant applied to the wire. This quantity can be controlled, on the one hand, by the sliding center content of the strand of material and, on the other hand, by the number of wraps of the wire, the feed or advance speed of the strand of material compared to the wire speed and the wire temperature.

In many cases, it is sufficient for the lubricant application to rub off the lubricant from the impregnated strand of material through the wire drawn through the loops. However, it is preferred to pull the wire through the loops of the strand of material at an elevated temperature and to use a lubricant since the wire temperature melts. In this way, the lubricant is applied to the wire surface as a uniform, coherent coating of the lubricant melt. The wire in the region of the loops preferably has a temperature between the melting temperature of the lubricant and 200 ° C.

Advantageously, the speed of advance or advance of the wire is much greater than that of the strand of material impregnated with the lubricant. The feed or preferred ratio of strand of material and wire in the range from 1: 100 to 1: 10,000 is particularly preferred.

The lubricant is expediently applied to the surface of the wire in an application thickness of 2 to 1000, preferably 20 to 100 mg / m². Such a thin application is particularly easy when using lubricants with melting points in the range from 35 to 140 ° C and when pulling the wire through the material strand loops at an elevated temperature. As a rule, the wire comes out of its pretreatment, such as electrical insulation coating, at an elevated temperature, so that it is expedient to use this temperature and to connect the lubricant coating directly.

It is often expedient to use a strand of material pre-impregnated with the lubricant, since in this way the device can be designed in the simplest and safest way. However, it is also possible to impregnate the strand of material essentially immediately before it comes into contact with the wire by passing the strand of material before the point of contact with the wire through a bath of the molten or liquid lubricant and, if appropriate, subsequently through a stripping device. In such an embodiment of the method according to the invention, an endlessly circulating strand of material can be used, which is guided in a closed circuit through the lubricant impregnation device and over the wire.

The strand of material impregnated with the lubricant can be moved simultaneously or in opposite directions with respect to the direction of advance of the wire. The former is mostly preferred.

The method according to the invention enables wires to be made free of emissions by sliding with the aid of simply constructed devices of reliable coating thickness in a simple manner. A particular advantage of the method according to the invention is that the control of the thread tension can be automatically and continuously determined whether the wire to be lubricated is actually supplied with lubricant. The method can therefore be particularly advantageously inserted into the fully automatic and unsupervised production of electrical winding wires. Furthermore, by detecting an increased thread tension, it can be indicated whether the wire has received a disturbing roughness in the previous coating process. A corresponding signal can be used for corrections in the painting process.

The device according to the invention for making a wire lubricious by coating the wire with a solid or liquid lubricant has a feed or feed device for the wire and a feed or feed device for at least one absorbent strand of material wrapped around the wire and soaked with the lubricant.

The feed or preferred device for the material strand preferably has a device which regulates the supply of the material strand in a controlled manner and a device which receives the material strand in a controlled manner and secures it against backflow.

The device which receives the material strand after depletion of lubricant is most simply a take-up spool which is expediently driven and pulls the material strand through the device. But it is also conceivable that the strand of material is pulled through the device by a separate device and then wound on a take-up spool. Instead of such a take-up reel, a suction device can also be used, which sucks off and accumulates the strand of material depleted in lubricant at the end of the device.

When using a take-up spool as the device that receives the material strand in a controlled manner, it is expedient if its core is conical or tapers close to one end. In such a take-up spool, the wound strand of material slides towards the tapered end, so that a roll is formed over the entire spool without a special traversing device.

The device dosing the supply of the strand of material in a controlled manner can be designed differently and can consist of a device that brakes the unwinding device for the strand of material. This device is expediently a separate drive roller with a pressure roller which, in cooperation, feed the strand of material to the device at a uniform speed. It is essential that the material strand between the feed device and the receiving device runs essentially taut and with essentially the same Speed of the device is supplied and removed from it.

A favorable device for this is that the device which regulates the supply of the material strand in a controlled manner and the device which receives the material in a controlled manner are coils driven by means of a synchronous motor, i.e. driven by the same motor. The synchronization of the two coils can expediently take place with the aid of a drive belt connecting the axes of rotation or shafts of the two coils, which drives, for example, via a belt pulley seated on the shaft of the respective coil

In order to change the amount of lubricant applied to the wire, you can make the drive roller interchangeable, for example. With a drive roller with a larger diameter, a larger amount of the strand of material is fed per revolution, so that a larger amount of lubricant is deposited on the wire per unit length thereof.

For fine regulation and to avoid material strand breaks, it is expedient to control the ratio of the dosage amount to the intake quantity of the material strand with the aid of a dancer device. When using a synchronous motor and a drive belt driving the take-up spool, it is expedient to arrange the dancer device in such a way that this drive belt is tightened or loosened by it. If, for example, the tension of the strand of material increases so that there is a risk of the strand of material breaking, the dancer device loosens the drive belt while increasing the slip, so that the increased tension of the strand of material is compensated for. If the tension is then reduced, the dancer device tightens the drive belt, thus reducing its slippage and increasing the tension of the strand of material.

According to a preferred embodiment of the device according to the invention, this has a braked or regulated unwinding device for the material strand, two deflection rollers and a driven winding device, the deflection rollers being arranged in relation to the wire to be made slidable such that the material strand between the two deflection rollers is the wire in the form of at least one loop.

In addition, an auxiliary roller is preferably arranged on the device in such a way that it deflects the strand of material which wraps around the wire twice at least once in opposite directions. It is further preferred that the feed or feed device for the wire gives it a linear movement in the area between the deflection rollers.

Furthermore, it is expedient that a device for regulating the preferred speed for the wire and / or the strand of material is provided. The take-up spool is expediently driven with a constant winding tension. The unwinding spool or a device connected downstream of it expediently has a specific winding resistance and or a specific unwinding speed.

In order to avoid tearing of the material strand, a dancer device was described above as preferred. Instead, a second motor can also be provided, which compensates for undesirably high tensile stresses which may lead to material strand breaks.

Since malfunctions can occur during operation of the device according to the invention which, if not observed, lead to the treated wire not being provided with lubricant at all or only insufficiently, it is advisable to provide the device with a special control device. This preferably consists of a deflection device for the strand of material which can be moved in two end positions and which can be pulled from the strand of material into a first end position and can be brought into a second end position by a pretensioning, a signal transmitter device triggering a signal in the second end position of the strand of material. Such a device triggers a signal if the material strand breaks, if the operator has forgotten to put on a new material strand roll, if the material strand tension is too low, if the drive motor is defective or the supply reel for the material strand is at the end. This deflection device expediently sits between the deflection rollers for the strand of material and advantageously near the wire. This deflection device can be a roller or a mandrel over which the thread is drawn. This deflection device is expediently arranged on a lever arm which can be pivoted about an axis and is preloaded by a spring. The deflection device can be designed such that in the first end position it closes an electrical contact, a signal of which is triggered when it is opened.

In such a device, the strand of material pulls the deflection device against the spring tension to the electrical contact under normal conditions. If the thread tension is now reduced or released, the deflection device is lifted from the electrical contact under the spring tension and goes into the second end position, whereby a signal is triggered, such as an optical and / or acoustic signal.

In practice, it is common to coat a larger number of wires with a wire enamel, these wires leaving the coating installation at a relatively short distance from one another. If such an application device must be provided for each wire leaving the coating system. This creates certain difficulties for reasons of space, since the application device is usually wider than the distance between the wires leaving the painting installation. To solve this problem, it is expedient if the deflection rollers for the strand of material are fastened to the device according to the invention on a sword which is articulated on the device and which can be pivoted or displaced in the horizontal and / or vertical direction. Such a pivoting can reduce the distance between the parallel wires passing through the lubricant coating system.

Fig. 1

eine erste und

Fig. 2

eine zweite Ausführungsform des Verfahrens nach der Erfindung in schematischer Weise.

Fig. 3

zeigt eine Seitenansicht einer Ausführungsform der Vorrichtung nach der Erfindung,

Fig. 4

zeigt einen senkrechten Schnitt durch den oberen Antriebsbereich der in Fig. 3 dargestellten Vorrichtung.

Fig. 5

zeigt eine Draufsicht auf den in Fig. 4 dargestellten Bereich der Vorrichtung.

Fig. 6

zeigt in vergrößerter Darstellung den Mittelabschnitt des Schwertes der in Fig. 3 dargestellten Vorrichtung.

Explain in the drawing

Fig. 1

a first and

Fig. 2

a second embodiment of the method according to the invention in a schematic manner.

Fig. 3

shows a side view of an embodiment of the device according to the invention,

Fig. 4

shows a vertical section through the upper drive region of the device shown in Fig. 3.

Fig. 5

shows a plan view of the area of the device shown in FIG. 4.

Fig. 6

shows in an enlarged view the central portion of the sword of the device shown in Fig. 3.

In Fig. 1, the wire is drawn in the direction of the arrow from a preferred device, not shown, linearly from right to left over the rollers 10 and 11 through four loops 5 of the strand of material (yarn or yarn) 2 soaked with lubricant. The material strand 2 is unwound from a braked unwinding device, which results in a certain winding resistance, and is guided in turns around the wire 1 to the deflecting roller 7 and from there to the driven rewinder 8 via a tension measuring device 4 and a deflection roller 6.

The embodiment of FIG. 2 differs from that of FIG. 1 by an additional auxiliary roller 9 between the deflection rollers 6 and 7. The auxiliary roller 9 enables the wire to be wrapped in opposite directions with the strand of material 2.

The device shown in FIGS. 3 to 6 has the structure described below, in which figures the same functional parts as in FIGS. 1 and 2 have the same reference numerals.

A housing 14 with a downwardly projecting carrier 13 and a pivotable sword 27 attached to it is arranged on the console 12. The supply spool or unwinding spool 3 for a thread 2 impregnated with lubricant is rotatably arranged on the console 12. The thread 2 runs around a thread deflecting shaft 15 via deflection rollers 39 and 16 three times around the guide roller 17 and the drive roller 18, the pressure roller 19 pressing against two thread loops of the drive roller 18. From the drive roller 18, the thread continues over the deflection rollers 22, 6, 7, 28, 26, 23 and 25 to the take-up or take-up spool 8 with the core 31 tapering conically to the left in the area between the deflection rollers 6 and 7 the thread 2 is the wire 1 guided in the same direction via the wire support rollers 11 and 10 and runs approximately in the middle between the guide rollers 6 and 7 via the guide dome 29, the function of which is described below.

The sword 27 can be pivoted in the horizontal and vertical directions, for example 180 ° horizontally and 15 ° vertically. The vertical swivels can be determined with a fixing screw 30 in an elongated hole.

As can be seen in FIG. 4, the housing 14 contains a synchronous motor which drives the exchangeable drive roller 18, which doses the thread feed, via a shaft 47. A pulley 33 is fastened on the shaft 47, via which the belt 48 runs via the deflection roller 36 to the pulley 34 on the shaft 46 of the take-up spool 8. Via this belt 48, the take-up spool is given the same thread take-off speed as the thread metering speed of the drive roller 18 by the synchronous motor 32. With the help of screw 21, the belt tension can be regulated.

The dancer device 24, which is biased into its normal position with the aid of the spring 35, is used to compensate for undesirably high thread tensions. With the help of the adjusting screw 20, the spring tension can be regulated.

If the thread tension is too high, the end of the dancer device with the deflection roller 25 is pulled down, the deflection roller 36 for the drive belt 48 also being pulled downward against the pretension by the spring 35 via the lever arm of the dancer device 24, as a result of which the drive belt 48 slips increased and the excessive thread tension is compensated.

As can be seen in particular in FIG. 6, the deflecting mandrel 29 is fastened in the region of the sword 27 on the mandrel lever 40, which can be pivoted about the axis of rotation 41. The mandrel lever 40 is biased upwards by means of the spring 42. This preload can be adjusted with the help of the regulating screw 45.

By pivoting the mandrel lever 40, the deflection dome 29 can be moved in the elongated hole 46 from the lower end position shown in FIG. 6 to an upper end position. In the lower end position shown in FIG. 6, the mandrel lever 40 bears against the actuating lever 43 of a microswitch 44 and thereby closes an electrical circuit. This lower end position assumes the deflection mandrel 29 when it is pulled from the thread 2 in the direction of arrow 50 in the normal operating position, when the thread, as shown in FIG. 3, runs over the deflection mandrel, when the thread breaks or the thread tension increases becomes small, the Umienkdorn 29 is pressed in the direction of arrow 51 under the force of the spring 42 in the slot 46, whereby the electrical contact is interrupted, which to trigger a signal, for example with the help of the signal lights 37 or 38 in Fig. 5 is made visible.

example 1

An electric winding wire with a diameter of 0.3 mm and a 40 µm increase in ester imide emerges from the coating device after the coating and drying device with a surface temperature of 200 ° C. The wire still has a surface temperature of 60 ° C in front of the fume cupboard, which is 4 m from the furnace exit. The wire is drawn off at 100 m / min. Using a thread pulling device as described in the drawing, a thread soaked in lubricant is drawn off at a take-off speed of 0.1 m / min with four-fold looping against the take-off direction of the winding drape. The thread tension is set to 10 g. The thread is a cotton thread with 40 g / km (40 tex) starch and a lubricant content of 35 to 45 g / km. The lubricant consists of 98% paraffin, 50 to 54 ° C and 2% Netzmiottel (FC 170). The thread was soaked, dipped and stripped using a rubber nozzle, cooled and wound up.

The thread pulling device is installed 0.5 m in front of the wire take-off device. The wire then has a lubricity which corresponds to the wire treated with paraffin solution

Example 2

An electric winding wire with a diameter of 0.58 mm and 40 µm esterimide varnish emerges from the varnishing device after the varnish application and drying device with a surface temperature of 200 ° C. The wire still has a surface temperature of 60 ° C in front of the fume cupboard, which is 4 m from the furnace exit. The wire is drawn off at 50 m / min. By means of a thread pulling device described according to the drawing, a lubricant-impregnated thread is drawn along with a pull-off speed of 0.063 m / min with four-fold looping in the pull-off direction of the winding wire. The thread tension is set to 50 g. The thread is a cotton thread with 45 g / km (45 tex) starch and a lubricant content of 75 g / km. Beeswax is used as a lubricant. The thread was soaked, cooled and wound up by immersion and stripping using a rubber nozzle.

The thread pulling device is installed 2 m behind the exit of the drying oven. The wire then has a lubricity that corresponds to the wire treated with paraffin solution.

Claims (31)

1. A method for making a wire slidable by coating the wire with a solid or liquid lubricant, characterised in that the wire is guided through at least one loop, resting on the wire, of at least one absorbent skein of material saturated with the lubricant, and the skein of material is therein advanced at a substantially constant speed which is slower than the feed speed of the wire.
2. A method according to Claim 1, characterised in that the absorbent skein of material used is a thread or 2-ply yarn, preferably of cotton.
3. A method according to Claim 1 or Claim 2, characterised in that the lubricant used is a paraffin, wax, oil and/or fat.
4. A method according to one or more of Claims 1 to 3, characterised in that the wire is drawn through the skein of material at increased temperature, and a solid lubricant is used which melts at the temperature of the wire.
5. A method according to one or more of Claims 1 to 4, characterised in that the feed- or drawing ratio of the skein of material to the wire is set at 1 : 100 to 1 : 10 000.
6. A method according to one or more of Claims 1 to 5, characterised in that a solid lubricant is used with a melting point in the range of 35 to 140°C.
7. A method according to one or more of Claims 1 to 6, characterised in that a lubricant is used with which a tenside, preferably a fluorine containing wetting agent, is mixed.
8. A method according to one or more of Claims 1 to 7, characterised in that the amount of lubricant applied is controlled by the feed- or initial drawing speed of the skein of material and/or wire and the lubricant content of the skein of material.
9. A method according to one or more of Claims 1 to 8, characterised in that the amount of lubricant applied to the wire is from 2 to 1000, preferably 20 to 100 mg/m² surface area of the wire.
10. A method according to one or more of Claims 1 to 9, characterised in that a skein of material is used which has been impregnated separately beforehand with the lubricant.
11. A method according to one or more of Claims 1 to 9, characterised in that the skein of material is saturated with the lubricant substantially directly before it makes contact with the wire.
12. A method according to Claim 11, characterised in that the skein of material is saturated with the liquid or molten lubricant by passing it through a bath of this lubricant.
13. A method according to Claim 12, characterised in that a continuously rotating skein of material is used and is guided in closed circulation through a lubricant steeping device and over the wire.
14. A method according to one or more of Claims 1 to 13, characterised in that the skein of material is wound one or more times in the same direction or in opposite directions around the wire.
15. A method according to one of Claims 1 to 14, characterised in that the temperature of the wire at the loop resting on it is set at a value between the melting temperature of the lubricant and 200°C.
16. An apparatus for making a wire (1) slidable by coating the wire (1) with a solid or liquid lubricant, having a feed- or drawing device (10, 11) for the wire (1), a feed- or drawing device (3, 6, 7, 8) for at least one absorbent skein of material (2) which is saturated with the lubricant and wound around the wire (1).
17. An apparatus according to Claim 16, characterised in that the feed-or drawing device for the skein of material (2) has a device which meters the supply of the skein of material in controlled manner and a device which takes up the skein of material in controlled manner and which provides a safeguard against backward movement.
18. An apparatus according to Claim 17, characterised in that the device which takes up the skein of material (2) in controlled manner is a take-up spool (8).
19. An apparatus according to Claim 17, characterised in that the device which takes up the skein of material (2) in controlled manner is a suction device.
20. An apparatus according to Claim 17 or Claim 18, characterised in that the device which meters the supply of the skein of material (2) in controlled manner and the device which takes up the skein of material in controlled manner are spools (18, 8) which are driven by means of a synchronous motor (32).
21. An apparatus according to Claim 20, characterised in that the two spools (8, 18) are synchronized by means of a drive belt (48) which connects the axes of rotation (46, 47) of the two spools.
22. An apparatus according to one of Claims 17 to 21, characterised by a compensating device (24) which controls the ratio of the revolutionary speed of the metering device (3) to the revolutionary speed of the take-up device (8) of the skein of material (2).
23. An apparatus according to Claim 21 and Claim 22, characterised in that the compensating device (24) tightens or loosens the drive belt (48).
24. An apparatus according to one of Claims 16 to 23, characterised in that for the skein of material it has a braked or controlled unwinding device (3), two direction-changing rollers (6, 7) and a driven wind-up device (8), wherein the direction-changing rollers are arranged in relation to the wire (1) which is to be made slidable in such a way that the skein of material encloses the wire in the form of at least one loop (5) between the two direction-changing rollers.
25. An apparatus according to Claim 24, characterised by an auxiliary roller (9) which is arranged in such a way that it changes the direction of the skein of material (2), wound around the wire (1) twice, at least once in opposite directions.
26. An apparatus according to one or more of Claims 16 to 25, characterised in that the feed- or drawing device for the wire (1) imparts a linear movement upon it in the region between the direction-changing rollers (6, 7).
27. An apparatus according to one of Claims 16 to 26, characterised by a direction-changing device (29), movable into two end positions, for the skein of material (2), which direction-changing device is able to be drawn by the skein of material into a first end position and is able to be brought by prestressing into a second end position, and also a signal transmitter device (44) which triggers a signal when the skein of material is in the second end position.
28. An apparatus according to Claim 27, characterised in that the direction-changing device (29) is arranged on a lever arm (40) prestressed by a spring (42) and pivotable about an axis (41).
29. An apparatus according to one of Claims 27 and 28, characterised in that the direction-changing device (29) closes an electrical contact in the first end position, which, when it opens, triggers a signal.
30. An apparatus according to one of Claims 24 to 29, characterised in that the direction-changing rollers (6, 7) are fixed to a strut (27) which is hinged to the apparatus and which is pivotable and/or displaceable horizontally and/or vertically.
31. An apparatus according to one of Claims 24 to 30, characterised in that the driven wind-up device (8) is a wind-up spool with a core (31) which tapers towards one end.

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