JPS6234430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic oil coating method for forming a thin oil film of a desired amount on the outer peripheral surface of a wire, such as a welding wire.

In recent years, welding wire is coated with a thin oil film of oil particles on the outer circumferential surface of the wire using static electricity for the purpose of rust prevention or for better feeding to the welding machine before being wound onto a take-up drum in the final forming process. I'm wearing it.

The reason for applying a thin oil film using static electricity is
It is difficult to form a uniform oil film on the outer circumferential surface of the wire with conventional lubricating devices that pass through oil-impregnated fibers, and frictional resistance with the wire guide etc. when feeding the wire to the welding machine is difficult. It increases and becomes impossible to send.
Also, if you try to form a uniform oil film, the amount of oil applied will increase, causing oil to adhere to the feed rollers of the welding machine, causing slips and making it impossible to feed, and diffusible hydrogen in the weld metal. This is because electrostatic oil application has the advantage of being able to form a thin, uniform oil film with a small amount and requiring only a small amount of oil consumption.

By the way, in the conventional general electrostatic oil application method, the atomized oil particles are sent by conveying air to an ionizer having a charging electrode, and the charged oil particles are transferred by the ionizer at a required speed. The oil is injected onto the oil to be coated and is deposited on the oil by a driving electrode, and the amount of coating is controlled by controlling the amount of conveying air in proportion to the transfer speed of the oil to be coated. It is common to do so. However, when this conventional method is applied to a wire, such as a welding wire, the amount of oil applied can be reduced by increasing (or decreasing) the amount of conveying air as the wire conveying speed increases (or decreases). Even if an attempt is made to control the amount within the desired tolerance range regardless of the wire transfer speed, a characteristic curve of the amount of oil applied per unit area versus the transfer speed (m/min) of the lubricant as shown in Figure 1 is obtained. Therefore, the control range that can be used to keep the amount of oil applied within the allowable range is relatively narrow.
This method has the disadvantage that it cannot follow a wide range of wire transfer speed changes such as min, where the minimum value and maximum value differ by about 10 times.

In addition, in order to eliminate the above-mentioned drawbacks, it is possible to control the amount of oil applied by making both the amount of conveying air and the voltage applied to the driving electrode directly proportional to the transfer speed of the welding wire, but if the object to be oiled is relatively thin. Since it is a wire rod,
If the voltage applied to the driving electrode is increased in order to increase the amount of coating, corona discharge occurs from the wire, making it difficult for the oil to adhere, making it difficult to control the amount of oil applied.

In view of the above, the present inventors have conducted various experiments and found that
When atomized oil is charged in an ionizer having a charged electrode and an atomized oil guide wall surrounding the charged electrode and injected onto a wire, the amount of oil adhering to the wire is determined by changing the voltage applied to the charged electrode in the ionizer. By controlling both the applied voltage to the ionizer electrode and the amount of conveying air, we were able to consistently apply coating regardless of the wide range of wire transfer speeds. The present invention was proposed based on the discovery that the amount of oil can be kept within an allowable range.

The present invention is an electrostatic lubrication method in which a desired amount of charged lubricant particles is applied to a wire rod that is transported at a required speed. and the charged electrode is injected onto the wire through an ionizer having an atomized oil guide wall surrounding the charged electrode, and the voltage applied to the charged electrode is set so that the amount of air conveyed from the blower is directly proportional to the transfer speed of the wire. It is characterized by being controlled in inverse proportion to each other.

Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 and 3 are longitudinal cross-sectional views showing an example of an electrostatic oil applicator suitable for carrying out the method of the present invention, and its A-
It is a sectional view on the A line.

In the figure, reference numeral 1 denotes a grounded case body through which a welding wire 2 is horizontally carried in and out through a carry-in guide 3 and a carry-out guide 4, and an oil storage tank 5 at the bottom.
is installed. Slots 6 are formed in the carry-in guide 3 and the carry-out guide 4, respectively, to facilitate insertion of the welding wire 2.

Atomization nozzles 7 suck and atomize the oil in the oil storage tank 5, and are arranged in large numbers along the longitudinal direction of the case body 1. The oil in 5 is sucked through a suction strainer 9, and the oil is atomized and sprayed.
Note that H is a heater disposed inside the oil storage tank 5, which is controlled by the temperature control circuit TC so that the temperature inside the oil storage tank 5 is at a required value, and is controlled by the temperature control circuit TC to prevent fluctuations in outside temperature.
This is intended to prevent the influence of a change in the diameter of spray particles from the atomizing nozzle 7 caused by a highly viscous oil agent.

Reference numeral 10 denotes a conveying air introduction pipe, and as shown in FIG.
2, and conveying air is introduced into the case body 1 through this introduction pipe 10. 13 is the introduction pipe 1
It is a round plate disposed on the upper part of the case body 1, which extends obliquely forward and downward from the rear plate 14 of the case body 1, and is used to collect relatively coarse particles among the oil particles atomized from the atomization nozzle 7. It is regulated to prevent direct transport into the ionizer. This buffer plate 13 is usually formed of a flat plate, but may also be made of a permeable plate made of punched metal or the like.

Reference numeral 15 denotes an ionizer disposed on the top of the full plate 13 at a required interval, and is a horizontal plate in which a long hole 17 parallel to the welding wire 2 fixed to the front plate 16 of the case body 1 is bored. 18 and an inclined plate 19 extending downward from the rear end and fixed to the rear plate 14. As is clear from FIG. 4, the ionizer 15 includes a pair of atomized oil guide walls 21 that guide atomized oil particles supplied through the elongated hole 17, and a pair of atomized oil guide walls 21 arranged in upper and lower stages within the guide walls 21. The atomized oil particles are charged by the high voltage supplied to the ionizer electrode 22. In this case, the atomized oil guide wall 21 is made of a conductive plate such as a metal plate or an insulating plate such as a vinyl chloride resin plate, and the oil particle spout 23 formed at the upper end that closely faces the welding wire 2 is located at the upper part. The width is gradually narrowed as the width increases, and the tapered shape is selected, and both sides are sealed so that the charged oil particles that are spouted out are sprayed in a concentrated manner onto the welding wire 2 without leaking to the sides. It is composed of

A convection hood 24 is disposed facing the ionizer 15 and the welding wire 2, and has an inverted U-shape in cross section. The atomizing oil guide wall 26 is attached to the lower surface of a mounting plate 27 that accommodates the atomizing oil particle guide wall 26, and its lower end side edge is inclined to widen to form an oil particle passage 28 between it and the inclined plate of the atomizing oil guide wall 21. Therefore, the charged oil particles ejected from the ionizer 15 are convected within the hood 24 and are again directed toward the welding wire 2 and discharged through the oil particle passage 28, so that the density of the oil particles near the welding wire 2 is stabilized. At the same time, the oil particles can be applied to the entire circumferential surface of the wire 2.

Reference numeral 29 is a driving electrode that is stretched in parallel with the welding wire 2 in the convection hood 24, and is used to direct the convecting oil particles to the welding wire 2 to which a high voltage is applied.
deposit on top.

Next, the operation of the electrostatic oil applicator described above will be explained with reference to FIG.

First, the welding wire 2 is inserted into the case body 1 through the carry-in guide 3 and the carry-out guide 4. Next, by opening the solenoid valve 38 installed in the compressed air supply pipe 8, compressed air is supplied to each atomizing nozzle 7 to atomize the oil into fine particles. At the same time, the blower 12 is driven to supply a required amount of transporting air into the case body 1, and a high voltage is applied to the ionizer electrode 22 and the follow-up electrode 29.

Next, when the welding wire 2 is started to be transferred, relatively fine particles of the oil particles atomized by the atomization nozzle 7 are introduced from the conveyance air introduction pipe 10 into the conveyance air and the atomization nozzle 7. The compressed air introduced through the baffle plate 13 and the front plate 16 of the case body is introduced into the ionizer 15 through the elongated hole 17.

The relatively fine oil particles introduced into the ionizer 15 are uniformly charged by the ionizer electrode 22, and some are collected on the atomized oil guide wall 21. Then, the ultrafine oil particles remaining without being collected are intensively sprayed onto the welding wire 2 from the tapered spout 23 of the atomized oil guide wall 21.
Coupled with the action of the driving electrode 29, the oil is efficiently and uniformly deposited on the welding wire 2, and an extremely thin oil film is formed on the welding wire 2.

Among the charged oil particles injected from the ionizer 15, the charged oil particles remaining without being deposited on the welding wire 2 are introduced into the convection hood 24, and are once raised inside the convection hood 24 by the carrier airflow, and then returned to the hood. 24 descends along the inner wall toward the welding wire 2 side. At this time, it is recharged by the driving electrode 29. These descending charged particles improve the density of charged oil particles near the welding wire 2 and maintain it at a required value, assisting the deposition of charged oil particles on the upper surface of the welding wire 2, and then depositing them. The remaining oil particles pass through the passage 28 and pass through the demister 26 and are collected in an external collection device 39.

Next, an electrostatic oil application control method according to the present invention which can be applied to the above-mentioned electrostatic oil application apparatus will be explained with reference to the schematic system diagram shown in FIG. In addition, in FIG. 5, for convenience of explanation, the welding wire 2 is transferred in the direction of the ionizer 1.
5 in the direction perpendicular to 5.

Reference numeral 30 is a tachometer generator that detects the transfer speed of the welding wire 2, and generates a DC detection voltage according to the transfer speed of the welding wire 2.

31 is an AC motor for driving the blower 12 to which the voltage detected by the tachogenerator 30 is supplied via the inverter 32 with a ratio/bias setting device, and the rotation speed is controlled in direct proportion to the transfer speed of the welding wire 2. . In this case, the relationship between the amount of conveyed air (%) from the blower 12 according to the rotation speed control of the drive motor 31 and the amount of oil deposited on the welding wire 2 per unit time is determined by using the voltage applied to the ionizer electrode 22 as a parameter. If expressed as , an oil application characteristic curve as shown in FIG. 6 is obtained in which the amount of oil adhesion increases as the amount of conveying air increases.

Reference numeral 33 is a high voltage generator for the ionizer electrode, in which the detection voltage of the tachogenerator 30 is supplied via the inverting amplifier 34, the voltage regulator 35, and the ratio/bias setting device 36, and is inversely proportional to the transfer speed of the welding wire 2. The output voltage is controlled by In this case, if the relationship between the voltage (KV) applied to the ionizer electrode 22 and the amount of oil adhering to the welding wire 2 per unit time is expressed using the amount of conveying air as a parameter, the approximate ionizer voltage as shown in FIG. An oil application characteristic curve is obtained in which the amount of oil adhesion decreases as the amount of oil increases.

The reason why the amount of oil adhesion decreases in inverse proportion to the increase in ionizer voltage is that the amount of oil deposited on the ionizer electrode 22
This is because the atomized oil guide wall 21 is arranged so as to surround the ionizer electrode, so as the voltage applied to the ionizer electrode increases, the amount of particles adsorbed and captured by the guide wall 21 increases due to the dust collection effect. .

Therefore, the rotation speed of the drive motor 31 of the blower 12, that is, the amount of conveying air, is directly proportionally controlled based on the detected voltage of the tachogenerator 30, and the ionizer electrode 2
By inversely proportionally controlling the voltage applied to 2,
As shown in FIG. 8, the transfer speed of the welding wire 2 is
When changing within the range of 150 to 1500 m/min, the amount of oil applied per unit area to the welding wire 2 could be kept within the predetermined tolerance range of ±20%.
In this case, the setting of the amount of oil applied can be easily changed by changing the setting values of the ratio/bias setting device of the inverter 32 and/or the voltage regulator 35 and the ratio/bias setting device 36.

In the above example, a case has been described in which the amount of conveying air is controlled by controlling the drive motor of the blower. It's okay.

Further, the transfer speed of the welding wire 2 can be detected not only by the tachometer generator 30 but also by using any other rotation detecting means or by using a line transfer speed setting signal.

Further, an inverting amplifier 34 for inversely proportionally controlling the high voltage generator 33 for the ionizer electrode based on the output of the tachogenerator 30 is connected between the voltage regulator 35 and the ratio/bias regulator 36, and between the ratio/bias regulator 36 and the high voltage generator. Alternatively, the inverting circuit may be inserted between the high voltage generator 33
It may also be built into the ratio/bias adjuster 36.

Furthermore, the atomized oil guide wall 21 of the ionizer 15 may be a pair of walls facing each other with the ionizer electrode 22 in between, or the guide wall 21 itself may be a cylinder.

Furthermore, it goes without saying that the method of the present invention can be applied not only to welding wires but also to other wire rods.

As described above, according to the present invention, the amount of conveying air is directly proportionally controlled according to the wire transport speed, and the voltage applied to the ionizer electrode is inversely proportionally controlled, so that regardless of changes in the wire transport speed, It has the excellent effect of automatically keeping the amount of oil applied to the wire rod accurately within a permissible range, and also being able to reliably follow even if the wire rod transfer speed changes over a wide range.

[Brief explanation of the drawing]

FIG. 1 is a characteristic curve diagram showing the relationship between line speed and amount of oil applied per unit area in the conventional electrostatic oil application control method, and FIGS. FIG. 4 is a perspective view showing an example of an ionizer; FIG. 5 is a schematic system diagram for explaining the method of the present invention; FIG. 7 and 7 are characteristic curves showing the relationship between the amount of conveying air and ionizer voltage and the amount of oil deposited per unit time, and FIG. 8 is a characteristic curve diagram showing the relationship between the line speed and the amount of oil applied per unit area according to the method of the present invention. It is a characteristic curve diagram showing the relationship. DESCRIPTION OF SYMBOLS 1...Case body, 2...Welding wire, 7...Atomization nozzle, 12...Blower, 15...Ionizer, 21...
Atomized oil guide wall, 22...Ionizer electrode, 29...
Drive-in electrode, 30... Tachometer generator, 31... Drive motor, 33... High voltage generator for ionizer, 34
...Inverting amplifier, 37...High voltage generator for driving electrode.

Claims (1)

[Claims] 1. In an electrostatic lubrication method in which a desired amount of charged lubricant particles are applied to a wire rod that is transported at a required speed, atomized lubricant is transferred to a charged electrode to which a high voltage is applied by conveying air from a blower and The wire is injected through an ionizer having an atomized oil guide wall that surrounds the charged electrode, and the amount of conveying air from the blower is directly proportional to the transfer speed of the wire, and the voltage applied to the charged electrode is inversely proportional to the transfer speed of the wire. A method for electrostatically applying oil to a wire rod, the method being characterized in that the electrostatic lubricating method is controlled individually.