KR20100022830A - Method for forming microstructured oil pocket on a fricktion surface - Google Patents

Abstract

According to the present invention, after the perforated etching mask adheres to the metal surface to be surface-treated according to the shape corresponding to the shape of the oil pocket to be formed on the metal surface, the metal surface portion exposed by the perforation is etched on the friction surface. A method of forming a micro oil pocket and a friction surface surface-treated by such a method. According to the method of the present invention, the oil pocket can be formed on the friction surface by a simple process without going through a process such as photolithography.

Description

METHOD FOR FORMING MICROSTRUCTURED OIL POCKET ON A FRICKTION SURFACE}

The present invention relates to a method of forming a fine oil pocket on the friction surface, and more particularly, to an oil pocket on the friction surface by a simple process by etching using an etching mask perforated in a shape corresponding to the shape of the oil pocket. It relates to a method that can form.

In general, internal combustion engines such as automobiles, railway vehicles, and ships include a cylinder block including a plurality of cylinders, a piston for reciprocating upward and downward in the cylinder, and a linear movement of the piston as a rotational movement of the crankshaft. It includes a connecting rod, a rocker arm fixed to the rocker arm shaft to open and close the intake valve and the exhaust valve by rotation of the camshaft, and parts such as a bearing for supporting the crank shaft or the cam shaft. In addition, a compressor used for compressing a refrigerant in an air conditioner, a refrigerator, or the like also includes a cylinder and a piston for reciprocating linear motion in the cylinder.

The cylinders and pistons, crankshafts and connecting rods, rocker arms and rocker arm shafts, rocker arms and camshafts, bearings, etc., are all friction surfaces that produce sliding or rolling friction, and in fact there are many other There is a friction surface. Such a friction surface is likely to be deteriorated in durability because it is easy to be worn by friction.

Therefore, attempts have been made to reduce friction such as minimizing the contact area on the friction surface, forming an appropriate oil film, or installing additional bearings. For example, a method is known in which independent lubricant pockets are installed on sliding bearing elements to improve friction or wear characteristics. In particular, Korean Utility Model Registration No. 409695 discloses a method of cutting an oil pocket on the inner circumferential surface of a cylinder liner using a superhard or heat-treated processing tool. However, in order to use such a tool, not only an expensive machine tool capable of moving in various axes, but also a problem that limits the shape, depth, and width of the pocket that can be formed in this way is more important. The more pockets to be formed, there is a problem that the machining time increases in proportion to this.

On the other hand, European Patent No. 0264341 discloses a method of forming an independent oil pocket on the inner peripheral surface of the cylinder liner using a laser beam. However, this method uses a very high power laser beam, which consumes enormous energy, and tends to cause fine metal fragments or high carbon steel regions to be formed on the laser beam processed portion. At this time, the loosely adhered metal fragments or high carbon steel parts may fall off and damage the engine of the internal combustion engine. Therefore, after laser processing, these parts must be removed by additional mechanical polishing.

In order to solve the above problems, US Patent No. 6,309,803 and German Patent Application DE10339606.3 use a photolithography method to apply a photosensitive material to the surface of a cylinder bore, and to expose, develop, etch and exfoliate oil. A method of forming a pocket is disclosed. However, in such a photolithography method, a problem is that the exposure technique for a circular or three-dimensional surface such as a cylinder bore surface has not yet been completely established. That is, in US Pat. No. 6,309,803, when light is emitted from a light emitting device, the light is reflected by a mirror installed inside the cylinder to the cylinder bore surface to expose only the intended portion of the photosensitive material applied thereto. However, this method has a problem that requires precise motion control of the mirror and the cylinder located inside the cylinder, and the more and more complicated shapes are desired to be formed on the cylinder bore surface, the more time is required for exposure to form them. In this respect, the same problems as in the case of using the laser or mechanical processing described above are encountered.

German Patent Application DE10339606.3 uses a method of rolling an exposure film having a pattern in a shape desired to be formed on a cylinder bore surface and pushing it into a cylinder bore mirror coated with a photosensitive material. Not only is it difficult to accurately match the pattern of the roll, but also the method of manually pushing in and out of the exposure film has a limitation that is not suitable for application in large-scale industrial production.

The present invention is to overcome the problems of the prior art as described above, one object of the present invention is to provide a fine shape on the friction surface by a simple and efficient process of low cost without going through an expensive and complicated process such as photolithography It is to provide a method for forming an oil pocket.

Another object of the present invention is to provide a friction surface having a finely shaped oil pocket formed by the method according to the present invention and a product comprising the same.

One aspect of the present invention for achieving the above object is

Preparing a perforated etching mask in a shape corresponding to the shape of the oil pocket to be formed on the metal surface;

Bringing the etching mask into close contact with the metal surface to be surface treated;

A method of forming a fine oil pocket on a friction surface comprising etching a portion of the metal surface exposed by the perforation. In the present invention, the etching step may be performed by wet etching or dry etching.

Another aspect of the present invention for achieving the above object relates to a friction surface comprising an oil pocket formed by the method of the present invention, as well as components and compressor components of various internal combustion engines including such friction surfaces.

In the present invention, by adopting an etching mask previously punched in the shape of the oil pocket to be formed on the friction surface, an independent oil pocket capable of significantly improving the friction characteristics of the friction surface can be more easily formed. According to the present invention, fine oil pockets on the friction surface can be easily etched by simply etching the etching mask to the surface without going through laser processing, expensive machine tools or UV exposure processes that are harmful to human bodies, as in the prior art. Can be formed.

In addition, while the prior art is limited to forming the oil pocket inside the curved surface, according to the method of the present invention, it is possible to form the oil pocket on the outer peripheral surface of the curved surface (see FIG. 12). Therefore, according to the method of the present invention, in addition to the inner circumferential surface of the cylinder liner, as illustrated in FIG. 8, the outer circumferential surface of the piston pin, the inner circumferential surface of the small end (small end) of the connecting rod which is frictionally engaged with the connecting rod, The inner circumferential surface of the large end (large end), the connecting rod bearing installed inside the inner circumferential surface, the outer circumferential surface of the crank pin to be frictionally engaged with it, both sides of the connecting rod large end caution and the crank arm to be rubbed with it, the shaft hole of the rocker arm, Fine oil pockets can also be formed on the inner circumferential surface of the bearing outer ring and the outer circumferential surface of the inner ring, thereby significantly improving their friction characteristics. As described above, according to the present invention, the oil pocket can be easily formed simultaneously on the structure in which the plane and the curved surface are connected.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

One aspect of the invention relates to a method of forming finely shaped oil pockets on a friction surface. The method of the present invention improves the lubrication performance by engraving the fine shape on the friction surface where sliding friction and rolling friction occurs, so that the fine shape functions as an oil pocket containing lubricating oil, thereby reducing friction and wear and consequently The present invention relates to a method for forming a fine oil pocket on a friction curved surface to improve the durability of the mechanism. The present invention is capable of forming oil pockets on flat as well as curved surfaces, for example cylinders and pistons of internal combustion engines, cylinders and pistons of compressors, connecting rods and crankshafts of internal combustion engines, rocker arms and rocker arm shafts, and other bearings. have.

1 is a schematic perspective view of an etching mask used in the method of forming an oil pocket according to an embodiment of the present invention, Figures 2 and 3 illustrate a process of adhering the oil pocket to the metal surface to form the oil pocket It is a schematic perspective view. When the oil pocket is formed on the metal surface by the method of one embodiment of the present invention, first, an etching mask prepared in advance in the shape of the oil pocket to be formed on the friction surface as shown in FIG. 1 is prepared. Subsequently, the etching mask is brought into close contact with the surface to be corroded as shown in FIG. 2 or FIG. 3. The etchant is then selectively etched through the perforation of the etch mask to contact the surface to selectively corrode only the metal surface corresponding to the perforated portion of the etch mask to form finely shaped oil pockets on the friction surface such as the metal surface.

1 illustrates an etching mask formed in a cylindrical shape, but the present invention is not limited thereto, and an etching mask manufactured in a shape corresponding to a shape of a friction surface to form an oil pocket may be used as shown in FIG. 7. In the present invention, the material of the etching mask is not particularly limited as long as it has corrosion resistance to the corrosion solution to be used in the subsequent etching process. In the present invention, the etching mask is, for example, low density polyethyl, high density polyethylene, polypropylene, biaxially stretched polypropylene, non-stretched polypropylene, polystyrene, stretched polystyrene, polyethylene terephthalate, stretched polyethylene terephthalate, polyethylene naphthalate, and polyb. Resins such as tylene telephthalate, polyvinylidene chloride, polyvinyl chloride, polybutylene terephthalate, polyamide, polyacrylate, polyvinylacetate, ethylene vinyl alcohol, polyimide, teflon, cellophane, or the like An etching mask made of metal having corrosion resistance to the corrosion solution to be used in the subsequent etching process may be used. Alternatively, an etch mask made of a metal that is not highly corrosion resistant may be made of low density poly ethylene, high density polyethylene, polypropylene, biaxially oriented polypropylene, non oriented polypropylene, polystyrene, oriented polystyrene, polyethylene terephthalate, oriented polyethylene terephthalate after drilling. Consisting of polyethylene naphthalate, polybutylene terephthalate, polyvinylidene chloride, polyvinyl chloride, polybutylene terephthalate, polyamide, polyacrylate, polyvinylacetate, ethylene vinyl alcohol, polyimide, teflon and cellophane It can be used if it gives corrosion resistance by the method of coating with 1 or more types of resin chosen from the group.

In the etching mask preparation step, the etching mask must be drilled to have a plurality of holes in a shape corresponding to the shape of the oil pocket to be formed on the metal surface. In this case, a punching method or a laser cutting method can be used. have. Among these drilling methods, an appropriate drilling method can be selected according to the material of the etching mask and the size of the drilling to be formed in the etching mask. In addition, as shown in the region A, B and C in Figure 1, it can be produced by varying the shape and density of the holes to be drilled.

As shown in FIG. 1, the cylindrical etching mask 300 first forms a plurality of holes 330 corresponding to the formation of an oil pocket by drilling a plate of the material by a press drilling method or laser processing. After cutting to size, it can be produced by a method of rolling (welding) by rolling it roundly. Alternatively, a pipe formed in advance with a required inner or outer diameter may be fabricated by laser drilling. The etching mask in other shapes can also be produced through a process such as bending and punching using a mold.

Next, the etching mask 300 manufactured as described above is brought into close contact with the friction surface 100 to form the oil pocket. When the friction surface to form the oil pocket is cylindrical and the oil pocket is formed inside the cylinder, as shown in FIG. 2, the etching mask 300 formed correspondingly to the cylindrical friction surface 100 is formed. The etching mask can be brought into close contact with the friction surface to form the oil pocket by inserting into the shell. Alternatively, in the case where the friction surface to form the oil pocket is cylindrical and the oil pocket is formed on the outside of the cylinder, an inner diameter of a size corresponding to the outer diameter of the cylindrical friction surface 100 is shown, as shown in FIG. The etching mask 300 having it can be covered and brought into close contact. If the friction surface to form the oil pocket is not cylindrical, as shown in Fig. 7, the contact surface is in close contact with the shape of the friction surface. At this time, if necessary, an adhesive may be used to more closely adhere the friction surface to the etching mask.

After the etching mask is brought into close contact with the friction surface on which the oil pocket is to be formed, the metal surface of the portion exposed by the plurality of holes of the etching mask is etched. At this time, etching can be performed by wet etching or dry etching. When wet etching is selected according to the material of the friction surface from known corrosion solutions such as iron chloride, copper chloride, sulfuric acid, nitric acid, hydrochloric acid, ammonium chloride, sodium hydroxide, potassium hydroxide, potassium ferricyanide and sodium ferricyanide solution 1 It may be etched by filling or spraying more than one corrosion solution.

On the other hand, in consideration of processing accuracy, shape, environmental problems, and the like, the oil pocket can be formed by dry etching. In dry etching, the active gas is ionized and ion etching using its physical energy, plasma etching using the chemical reaction of the plasma-formed active gas, reactive ion etching (RIE) using both chemical and physical reactions, and the like. It can be etched by the method. Here, in selecting the type of the corrosion solution or the plasma, a type is selected in which the friction surface is corroded while the etching mask is not corroded.

Through the above etching process, an oil pocket is formed on the friction surface in a shape punched in the etching mask. The etching time is mainly determined by the depth of the oil pocket shape to be formed by corrosion.

On the other hand, as shown in FIG. 4, a minute gap d may occur between the friction surface 100 and the etching mask 300 due to a minute error in close contact between the etching masks. In this case, as shown in FIG. 5, the corrosion solution flows into the gap, and thus the oil pocket may be formed differently from the intended shape. If these results are unacceptable due to the nature of the applied product, as shown in FIG. 6, friction before the etching mask 300 is brought into close contact with the friction surface 100 in order to prevent corrosion of portions other than the perforated portion. An anticorrosion material 400 may be filled in the gap between the surface 100 and the etching mask 300. Non-limiting examples of anti-corrosion materials that can be used include silicone oils, fluorine oils, industrial lubricants, vegetable oils such as palm oil, palm oil, olive oil, hydrocarbon compounds such as natural resins, paraffin, oleic acid, palmitic acid, lauric acid, stearic acid Fatty acids such as, but not limited to these. In this way, when the anti-corrosive material is applied to the friction surface and the etching mask is brought into close contact with the etching mask, these materials are filled in the gap between the etching mask and the friction surface, and the corrosion solution is prevented from contacting the friction surface to prevent corrosion of unwanted areas. Can be prevented.

Another method for enhancing the adhesion is to use the elasticity of the etching mask material. That is, for example, as shown in FIG. 7, the etching mask 300 may be opened and placed on the friction surface 100 having an arbitrary shape, and then may be brought into close contact with the friction surface by the elasticity of the etching mask. Alternatively, in the case of the etching mask which is in close contact with the inside of the cylinder, as shown in Figs. 8 and 9, the etching mask 300 " is made of a cylinder having a diameter larger than the diameter of the cylinder, A portion of the etching mask 300 "may be cut out so that the length is the same as the length of the inside of the cylindrical friction surface 100". The cylindrical friction surface ( Inserting into the interior of 100 ", the elasticity of the etching mask 300" itself makes it more intimate with the inner circumferential surface of the cylindrical friction surface 100 ".

On the contrary, in the case of being in close contact with the outer circumferential surface of the cylindrical friction surface, as shown in Figs. 8 and 10, the etching mask 300 "'is expanded and located outside of the cylindrical friction surface 100", and expansion is performed. When released, it is in close contact with the outer circumferential surface of the cylindrical friction surface 100 "while being contracted by the elasticity of the material of the etching mask 300" '. In this case, of course, the lengths of the two etching masks except the cutout portion should be equal to the length of the outer periphery of the cylinder. In making the incision, it is not necessary to make a straight incision, but may be rounded as shown in FIG. 10 and may be cut in an arbitrary shape.

After etching for a predetermined time, it is possible to form a fine oil pocket on the friction surface by checking whether the etching is uniformly performed over the entire surface to the required depth and removing the etching mask that is in close contact with the friction surface.

On the other hand, if the anti-corrosive material is filled between the gap between the etching mask and the friction surface as described above, some of the anti-corrosive material may be mixed with the corrosive solution and enter the corrosive storage tank, which is removed from the corrosive solution using an oil / water separator. It is preferable. After removing the etching mask, the filling material remaining on the friction surface can be dissolved and removed by spraying a known alkaline solution such as NaOH or KOH aqueous solution. Since it is necessary to prevent corrosion due to moisture, it may be wiped off only physically so that a small amount of remaining oil on the surface may serve as a rust preventive.

Another aspect of the invention relates to a friction surface comprising an oil pocket formed by the method of the invention. An example of such a friction surface is shown in FIG. As shown in FIG. 11, the friction surface of one embodiment of the present invention includes a plurality of oil pockets 200 on the surface of the friction surface 100, and oil 300 is injected into the oil pocket 200. Therefore, the friction generated in the process of the friction surface is reduced. Such surface may be flat or curved.

Another aspect of the invention may be an article comprising such a friction surface. Such products may include internal combustion engines such as automobiles, railroad cars, ships, or the like, or compressors used to compress refrigerant in air conditioners, refrigerators, and the like. The friction surface of the present invention may be included in a cylinder liner, piston pin, connecting rod, connecting rod bearing, rocker arm, crankshaft, or bearing of an internal combustion engine. In addition, compressors such as air conditioners, refrigerators, and the like may also include a friction surface having finely shaped oil pockets of the present invention. 12 is an oil pocket formed on the inner circumferential surface of the conrod small end and the large end. FIG. 13 is a perspective view of a rocker arm in which an oil pocket 83 is formed in the shaft hole, and FIG. 14 is a perspective view of a bearing outer ring ring having oil pocket forming portions 84 and 85 on its inner circumferential surface.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the protection scope of the present invention.

Example

A resin plate made of polypropylene was molded to a thickness of 0.5 mm, and a 0.3 mm X 1.5 mm perforation was formed at left and right 3 mm and 1.5 mm up and down intervals to prepare an etching mask. The obtained etching mask was then brought into close contact with the inner circumferential surface of the cylinder block of the engine to form oil pockets according to the method shown in FIG. Then, the inner peripheral surface of the cylinder block exposed by the drilling was etched with iron chloride solution for 2 minutes, and then the etching mask was removed to form an oil pocket on the inner peripheral surface of the cylinder block. Fig. 15 is a photograph of the inner circumferential surface of the cylinder block thus obtained. Referring to FIG. 15, it can be seen that a portion of the inner circumferential surface of the cylinder block is in contact with the corrosion liquid through a perforated portion to form a fine groove. If oil is added to the inside of these grooves will be able to function as an oil pocket.

Although the present invention has been described in detail with reference to preferred embodiments of the present invention, the present invention is not limited to the above-described embodiments, and many modifications are made by those skilled in the art to which the present invention pertains within the scope of the technical idea of the present invention. This possibility will be self-evident.

1 is a perspective view showing an example of an etching mask used in the present invention.

2 is a perspective view illustrating the step of contacting an etching mask with a metal surface to form oil pockets on the friction surface.

3 is a perspective view illustrating the steps of another embodiment of contacting an etching mask to a metal surface to form oil pockets on the friction surface.

4 and 5 are schematic diagrams for explaining the problem when a gap exists between the friction surface and the etching mask.

6 is a schematic view of a state in which a corrosion preventing material is filled in a gap between the friction surface and the etching mask.

7 and 8 are plan schematic views showing etching masks manufactured in a form corresponding to the shape of the friction surface to form the oil pocket.

9 and 10 are perspective views illustrating a method of bringing the friction surface into close contact with the etching mask using the elasticity of the etching mask material.

11 is a side cross-sectional schematic view of a friction surface including an oil pocket according to an embodiment of the present invention.

12 is a perspective view of a conrod to which a friction surface having an oil pocket of the present invention is applied.

13 is a perspective view of the rocker arm in which the oil pocket 83 is formed in the shaft hole.

Fig. 14 is a perspective view of the bearing outer ring having the oil pocket forming portions 84 and 85 on its inner circumferential surface.

15 is a photograph of the inner circumferential surface of the cylinder block in which the oil pocket is formed on the inner circumferential surface according to the embodiment.

* Description of the symbols for the main parts of the drawings *

100: friction surface (metal surface) 300: etching mask

Claims (10)

Preparing a perforated etching mask in a shape corresponding to the shape of the oil pocket to be formed on the metal surface; Bringing the etching mask into close contact with the metal surface to be surface treated; Etching a portion of the metal surface exposed by the perforation. The method of claim 1, wherein the etching mask is a corrosion-resistant metal or low-density polyethylen, high-density polyethylene, polypropylene, biaxially stretched polypropylene, non-stretched polypropylene, polystyrene, stretched polystyrene, polyethylene terephthalate, stretched polyethylene tere With phthalates, polyethylene naphthalates, polybutylene terephthalates, polyvinylidene chlorides, polyvinyl chloride, polybutylene terephthalates, polyamides, polyacrylates, polyvinylacetates, ethylenevinylalcohols, polyimides, teflon, and cellophane A method for forming a fine oil pocket on a friction surface, characterized in that it is made of at least one polymer selected from the group consisting of. The method of claim 1, wherein the etching mask is low-density polyethylen, high-density polyethylene, polypropylene, biaxially stretched polypropylene, non-stretched polypropylene, polystyrene, stretched polystyrene, polyethylene terephthalate, stretched polyethylene terephthalate, polyethylene Selected from the group consisting of phthalates, polybutylene terephthalates, polyvinylidene chloride, polyvinyl chloride, polybutylene terephthalate, polyamides, polyacrylates, polyvinylacetates, ethylene vinyl alcohols, polyimides, teflon and cellophane A method of forming a micro-shaped oil pocket on the friction surface, characterized in that the at least one polymer is coated. The method of claim 1, wherein the etching step is performed by wet etching. The method of claim 1, wherein the etching step is performed by dry etching. The method of claim 1, wherein the method further comprises filling a gap between the etch mask and the metal surface with an anticorrosion material. The method of claim 6, wherein the corrosion preventing material is selected from the group consisting of silicone oil, fluorine oil, industrial lubricating oil, palm oil, palm oil, olive oil, natural resin, paraffin, oleic acid, palmitic acid, lauric acid and stearic acid. A method for forming a fine oil pocket on a friction surface characterized in that. A friction surface comprising an oil pocket formed by the method of any one of claims 1 to 6. The article of claim 8 comprising the friction surface. 10. The article of claim 9, wherein the article is a cylinder liner, piston pin, connecting rod, connecting rod bearing, rocker arm, crankshaft, or bearing.

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