US3217834A - Process of lubrication for metal frictional surfaces - Google Patents

Description

I N 1965 KENICHI NAKAMURA 3,217,834

PROCESS OF LUBRICATION FOR METAL FRICTIONAL SURFACES Filed June 14, 1963 2 Sheets-Sheet 1 F ag. 1

INVENTOR.

1965 KENICHI NAKAMURA 3,

PROCESS OF LUBRICATION FOR METAL FRICTIONAL SURFACES 2 Sheets-Sheet 2 Filed June 14, 1963 Lubricant I Current, A Mater Oil 7 Non o Motor Oil Organic Phosphite Compound N 13,6. 10 amp -6. a p

PROCESS OF LUBRICATION FOR METAL FRICTIONAL SURFACES Kenichi Nahamura, 12 Hara-cho, Bunlryo-lru,

Tokyo, Japan Filed June 14, 1963, Ser. No. 287,364 Ciairns priority, application Japan, June 22, 1962, 37/25,543, Patent 33/4,875 3 Claims. (Cl. 184-1) The present invention relates to a process of lubrication for metal frictional surfaces wherein performance characteristics of lubricants are considerably improved by the flow of an electric current between the frictional surfaces, so as to reduce the friction therebetween and to increase the resistance against abrasion of the frictional surfaces.

It was believed that upon passing an electric current between the frictional surfaces, the abrasion of the frictional surfaces is increased. However, it has now been found that an electric current brings about an effect improving the wear resisting property of the frictional surfaces, contrary to the previous belief, if appropriate additives are provided in the lubricating oil.

It is, therefore, one object of the present invention to provide a lubricating process for metal frictional surfaces, wherein additives are provided in the lubricating oil, whereby the activity of the adsorbed molecules on the frictional surfaces is accelerated by an electric current. The mixture of lubricating oil and additives is used as a lubricant on the frictional surfaces, and a film of metallic compounds having good lubricating performance is formed by the electric current whereby, remarkably, the wear resisting properties of the frictional surfaces are caused to increase.

Various lubricants of different kind bring about good lubricating conditions by an electrolytic polishing action.

As additives, organic phosphite compounds or other organic compounds are effectively used. The amount of additives, however, is effective below 5%, depending upon the type of the additives and base oils used.

As an electric current, D.C. (direct current) is preferable, however, alternating current may also be applied. An adequate value of the electric current to be practically applied is dependent upon the surface pressure, the sliding speed, the finished condition, the dimensional area of the frictional surfaces, as well as the type of frictional metals and additives.

The values of the electric current are, in general, a few volts at ll amperes, since a large electric power is not necessary. Consequently, expenses required for the additives and the electric power consumption are considerably reduced in accordance with the present invention.

As the result of an abrasion test by using an abrasion testing machine (Timken type, four-ball tester), under the best conditions, the abrasion has been reduced, according to the present invention, about 50% and the pressure bearing capacity has been increased about 25% in comparison with the condition, if no electric current is applied. Also, in a wire drawing test of a piano wire, the drawing force is reduced by Thus, it has been found that the present manner of operation is very useful, as to the increase of abrasion resistance of a die and the reduction of the applied power.

The present lubricating process is applicable to various sliding surfaces, such as to a unit of a shaft and a bearing, an engaging surface of a worm gear and a worm wheel, etc. and has the advantage of raising the abrasion resistance of these rotating surfaces.

This process is also applicable to a wide range of processes for metal-working lubrication, such as wire drawing, pipe drawing, thread rolling, extrusion and blanking, and serves the purpose of increasing the abrasion resistance of tools and of decreasing the working power.

nited States Patent 0 It is one of the advantageous features of the present invention that the process can be practiced usefully by simply mounting a small electric equipment on already existing equipment or apparatus.

With this and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is a front elevation partly in section of a bearing for practicing the process of the present invention;

FIG. 2 is a front elevation partly in section of a wire drawing apparatus for practicing the present invention;

FIG. 3A is a front elevation of a construction of Timken type abrasion testing machine used in a fundamental abrasion experiment in the present invention;

FIG. 3B is a side view of the Timken type abrasion testing machine;

FIG. 4 is a diagram of one example of experimental results effected by using a Timken type abrasion testing machine; and

FIG. 5 is a diagram of one example of experimental results obtained by an application of the method to wire drawing.

Referring now to the drawings, FIG. 1 shows one example of the application of the process of the present invention to a bearing comprising bearing housings 1 and 2, a shaft 3 and a bearing member 4. An oil ring 5 is inserted and a lubricant 6 is fed into the bearing housings 1 and 2. Electric current flows to the bearing housing 1 by means of a lead wire 7 connected with the bearing housing 1 and then passes. to a lead wire 8 connected with hearing housing 2 through the bearing member 4, the friction surfaces and the shaft 3.

Referring again to the drawings, FIG. 2 shows one example of the application to a wire drawing machine, wherein a die 9 is supported by a die holder 10 and includes a winding drum 11 of a wire drawing machine. Rollers 12, 13 and 14 are fixed to a lubricant box 15. The latter is mounted on a frame 20 of the wire drawing machine insulated electrically by an insulator 16. A wire 17 passes through the lubricant box 15 by using the rollers 12, 13 and 14, so as to be covered on its surface with lubricating oil. The wire 17 then passes through the die 9, to be wound on the winding drum 11.

The electric current flows from a lead wire 18 to a wire 17, and passes through the rollers 12, 13 and 14 fixed on the lubricant box 15 and then reaches the lead wire 19 through the friction surfaces between the wire 17 and the die 9.

The results of a fundamental abrasion test and an applied experiment in connection with this process will now be described for each of the examples.

FIGS. 3A and 3B show a partial schematic diagram of a Timken type abrasion testing machine used in the fundamental abrasion test. This testing machine has been equipped with a torque pick-up using a strain gauge.

FIGS. 3A and 3B disclose specimens 21 and 22, one being a roller 31 (10 mm. (15 x 10 mm.) and the other being a ring 22 (40 mm. The ring 22 rotates while being dipped into a lubricant in an oil tank 23. The roller 21 is attached to a lever 24 and the rotating ring 22 is subjected to a load by a weight 25 suspended at one end of the lever 24. The electric current flows to the frictional surfaces between the roller 21 and the ring 22 through contact points 26 and 27.

FIG. 4 discloses a diagram of one example of experimental results by using the testing machine set forth above. This experiment has been carried out with a sliding speed of 28.9 m./min. and the amount of wear of the roller has been measured after a sliding distance of 433 m. In the diagram, the ordinate shows a volume of wear of the roller and the abscissa shows the load.

The electric current used was a full-wave rectified D.C. As a lubricant, a motor oil, to which 1% of organic phosphite compound has been added, was used. As to the roller and ring material applied in the experiment, a high carbon chromium bearing steel was used. It has been clearly observed that the wear was definitely reduced by the flow of an electric current. The coefficient of friction was also reduced more or less (0.01).

FIG. 5 discloses a diagram of one example of experimental results obtained by the application of this method to wire drawing.

A motor oil, to which 5% of organic phosphite compound has been added, was used as a lubricant. The current which was used was rectified D.C. in the same manner as in the above example. A piano wire, having a carbon content of 0.71%, which was subjected to a first drawing on a diameter of 3.04 mm. and then drawn through two dies to a diameter of 2.65 mm., in order to provide a finished-surface condition, was used.

This piano wire was drawn through a tungsten carbide die of a half angle 5 to a diameter of 2.40 mm. (reduction of area 18%).

Drawing speeds were varied and the measured results of the drawing forces for each drawing speed are shown in FIG. 5. A coefficient of friction was calculated from the formula of the drawing force derived by P. W. Whitton.

This figure shows clearly that the drawing force is decreased by the flow of current. The reduction of the drawing force teaches that the coefiicient of friction between the wire and the die is decreased.

In order to examine the cause of the reduction of the friction and the abrasion, the observation of electron difiraction phenomena on the frictional surfaces was performed by using motor oil, to which organic phosphite compounds have been added, as a lubricant.

As the result of the above, it is found that when no current flows on the frictional surfaces Fe P and FeP exist on the frictional surfaces; however, when electric current flows across the frictional surfaces, a diffraction pattern of Fe l and FeP appears clearly. Additionally,

i it is found that a diffraction pattern of FePO -2H O and 2Fe O P O -2H O, which were not found, if no electric current flows, appears clearly. Consequently, it is considered that the formation of a film of metal compounds on frictional surfaces is accelerated by the how of the electric current.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A process of lubrication for metal frictional surfaces comprising the steps of adding up to about 5% of organic phosphite compounds to lubricating oil applied to frictional surfaces, and

passing a substantially uniform electric current across said frictional surfaces and through said lubricating oil with said added compounds in order to initiate and to accelerate the formation of a film of metal compounds on said frictional surfaces, thereby increasing the lubrication performance of said lubricating oil and reducing the coefficient of friction between said frictional surfaces.

2. The process, as set forth in claim 1, wherein said step of passing electric current through said mixture is performed by direct current.

3. The process, as set forth in claim 1, wherein said step of passing electric current through said mixture is performed by alternating current.

References Qited by the Examiner UNITED STATES PATENTS 2,661,825 1/1949 Winslow 192-215 3,052,316 9/1962 Praberger 1841 3,072,444 1/1963 Klass 3081 LAVERNE D. GEIGER, Primary Examiner.

MILTON KAUFMAN, Examiner.

Claims (1)

1. A PROCESS OF LUBRICATION FOR METAL FRICTIONAL SURFACES COMPRISING THE STEPS OF ADDING UP TO ABOUT 5% OF ORGANIC PHOSPHITE COMPOUNDS TO LUBRICATING OIL APPLIED TO FRICTIONAL SURFACES, AND PASSING A SUBSTANTIALLY UNIFORM ELECTRIC CURRENT ACROSS SAID FRICTION SURFACES AND THROUGH SAID LUBRICATING OIL WITH SAID ADDED COMPOUNDS IN ORDER TO INITIATE AND TO ACCELERATE THE FORMATION OF A FILM OF METAL COMPOUNDS ON SAID FRICTIONAL SURFACES, THEREBY INCREASING THE LUBRICATION PERFORMANCE OF SAID LUBRICATING OIL AND REDUCING THE COEFFICIENT OF FRICTION BETWEEN SAID FRICTIONAL SURFACES.

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