KR20070033058A - SLIDING BEARING SINTERED WITH Fe COMPOUND ON STEEL BASE - Google Patents

Abstract

A sliding bearing sintered with Fe compound on a steel base is provided to uniform and stabilize a sintered metal crystal to increase high load-resistance and wearing-resistance. A sliding bearing sintered with Fe compound on a steel base includes steel bases(13), an adhesion layer(X), and a friction layer(Y). The adhesion layer is sintered on friction surfaces of the steel bases with ferro-metal powders to a certain thickness. The friction layer is sintered on an upper surface of the adhesion layer simultaneously forming the adhesion layer. In the friction layer, solid lubrication agent particulates(10a,10b) having a particle size of 0.04mm ~ 2mm are arranged in the ferro-metal powders at predetermined gaps. The solid lubrication agent is at least one or two agents selected from graphite, MoS2, and WS2.

Description

SLIDING BEARING SINTERED WITH Fe COMPOUND ON STEEL BASE}

1 is a perspective view of a flat plate steel-based iron-based sintered sliding bearing according to the present invention.

Figure 2 is a perspective view of a bush-type steel base iron sintered sliding bearing according to the present invention.

3A to 3E are process drawings showing a method of arranging the granular solid lubricant in the manufacturing step of the flat sliding bearing shown in FIG. 1.

Figures 4a to 4e is a process chart showing a method for arranging the granular solid lubricant in the manufacturing step of the bush-type sliding bearing shown in FIG.

Figure 5 is a flow chart showing a method of manufacturing a steel-based iron-based sintered sliding bearing according to the present invention.

             Explanation of symbols on the main parts of the drawings

10a, 10b, 20a, 20b: granular solid lubricant 11, 21: sintered metal

12, 22: joint surface 13, 23: steel substrate

14, 24: ferrous metal powder 15: lower mold

16, 26: side mold 17, 27: puncher

18, 28: press 25: core mold

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sliding bearings in which regular solid lubricants are regularly arranged, and more particularly, granular graphite, granular molybdenum disulfide (MoS ₂ ) or granular tungsten disulfide (WS ₂ ) in an iron-based metal powder. The present invention relates to a steel-based iron-based sintered sliding bearing in which sintered and bonded granular bodies of solid lubricants, etc., are sintered to the surface of steel materials.

In general, sliding bearings are mechanical elements in which overlay layers such as iron alloys, copper alloys, aluminum alloys, copper-lead alloys, and synthetic resin composites are formed on the upper surface of steel substrates or iron-based sintered layers. It is used as supporting part or sliding part of journal or reciprocating device in machine tool, industrial machine, etc., and divided into bush type (cylindrical type, semi-cylindrical type) and flat type according to its shape and function. In particular, the present invention relates to a steel-based iron-based sintered sliding bearing to withstand high loads by forming an overlay layer by sintering and joining the iron-based metal powder and a solid lubricant on the upper surface of the steel substrate.

Conventionally, in order to achieve high load resistance and high wear resistance, iron-based metal powder (mixed with other metal powders such as copper, nickel, tin, etc.) and graphite on a steel substrate surface made of carbon steel or stainless steel, etc. Steel-based iron-based sintering material made by pressing and molding solid lubricant mixed metal powder mixed with fine powder of solid lubricant such as molybdenum disulfide and tungsten disulfide by pressing or rolling roller, and then sintering in a sintering furnace Many sliding bearings are introduced. The biggest technical problem in these steel-based iron-based sintered bearings is the joining between the steel substrate (also referred to as "steel if metal") and the sintered material (sintered alloy layer). It is possible to form and sinter the iron-based alloying layer containing a large amount of graphite and molybdenum disulfide only without damaging the bonding property between the steel substrate and the sintered material, and the practical use for structural purposes is possible. Therefore, most of the inventions related to steel-based iron-based sintered bearings include a large amount of solid lubricant on the friction side, and at the same time, the focus is on improving the adhesion between the steel-based steel and the sintered material.

An example thereof is described in Korean Patent Publication No. 10-286246. No. 10-286246 is "steel back metal; and the steel back metal is bonded at the same time and sintered at 1065 ℃ -1095 ℃, 10-30 parts by weight of the iron-based alloying layer consisting of iron; and, And a dry lubricant contained in the iron-based alloying layer; wherein the dry lubricant is at least one of 0.1 parts by weight to 6.5 parts by weight of graphite or 0.1 parts by weight to 7.0 parts by weight of molybdenum disulfide. It is starting. In addition, the present invention No. 10-286246 is "the step of inserting a copper-plated steel if the metal into the mold of the molding apparatus: 10-30 parts by weight of copper, 0.1 to 6.5 graphite between the core and the steel if the metal A part by weight, 0.1 to 7.0 parts by weight of molybdenum disulfide and the remainder are filled with a metal mixed powder composed of iron, and then inserting an upper pressure member at the top of the mold; 50-300 kg of the upper pressure member or the lower pressure member, respectively Selectively pressurizing at a pressure of / cm < 2 > to form the metal mixed powder: by holding the molded product produced in the forming step together with the steel, if the metal, at a temperature of 1065-1095 DEG C under a predetermined gas atmosphere for 3-25 minutes. A sliding bearing manufacturing method is disclosed, comprising a step of sintering the molded body with a small alloy layer and simultaneously bonding the metal to the metal.

In order to achieve good bonding between the metal and the small bond layer, the composition ratio of graphite or molybdenum disulfide powder, which is a solid lubricant, is 0.1 parts by weight to 6.5 parts by weight or 0.1 parts by weight of molybdenum disulfide, respectively. It is limited to 7.0 parts by weight, the composition ratio of copper powder mixed with iron powder is limited to 10-30 parts by weight, and the sintering temperature is limited to the range of 30 ° C around 1083 ° C, which is the melting point of copper, to sinter in the transition region of solid state sintering and liquid phase sintering It is argued that this is what makes this happen.

However, a method for producing iron-based small alloys for sliding bearings, which limits the copper composition ratio and sinters at a temperature near the melting point of copper, is a technique that has already been used before the filing of the invention of No. 10-286246 (Japanese Patent Application No. 95-224746). Restriction of the composition ratio of the solid lubricant is meaningful only when the copper powder and the solid lubricant are mixed in powder form with iron powder and pressure-molded outside the sintering furnace, and then sintered under the gas atmosphere or vacuum pressure in the sintering furnace. will be. That is, if the solid lubricant is not mixed with the mixed powder of iron and copper in the form of powder, or if pressure molding and sintering are performed simultaneously in the sintering furnace, the restriction of the composition ratio or the sintering temperature according to the invention of No. 10-286246 has no meaning. It is not there. Rather, according to the invention of No. 10-286246, the content of the solid lubricant is too low, the lubricity is poor, and the possibility of burning (stretching property) with the counterpart (journal or reciprocating device) under high load is not only high, Due to leaching, there is a problem in that the small-bonded gold layer is uneven and the density is lowered. That is, when the solid lubricant is mixed with the metal powder in the form of powder and sintered, and there is no pressure on the sintering material during the sintering process, even if there is a metal, the metal part of the three-dimensional network structure in the sintered body (iron alloy part) ) Is not maintained continuously due to the distribution of fine solid lubricants, resulting in discontinuous and non-uniform sintered metal structures, resulting in weak hardness and strength, and lowering of allowable loads of 300-500kg / ㎠ or more (maximum 700kg / ㎠ or more). It is difficult to use as a bearing for heavy and harsh environments. Graphite or molybdenum disulfide, which is usually used as a solid lubricant in bearings, is a non-metallic mineral that functions as a material that prevents and suppresses sintering, and because it has a specific volume (volume per unit weight), only several weight percent of the iron powder mixture is used. Even if contained in powder form, the molding and sintering are fundamentally difficult, so even if the sintering is partially, the part is very weak in strength and difficult to use for structural purposes. Moreover, these non-metallic inorganic materials are used as interfacial bonding barriers because they are included in the iron alloy layer and sintered together. Will be done. Therefore, when the solid lubricant is mixed with the metal powder in the form of powder and sintered to the metal, the amount of addition of the solid lubricant is inevitably limited. When the amount of the solid lubricant is limited, the sliding bearings are insufficient in lubricity and are easily adhered to the counterpart. Since the oil-free lubrication time is short, the wet lubricant such as lubricating oil or grease needs to be impregnated again.

It is the invention of Korea Patent Publication No. 10-496655 to solve the problems of the above-described invention 10-286246.

The invention of No. 10-496655 discloses that a metal mixed powder made of graphite, copper, iron, etc. is coated on the back of the metal plate for the purpose of sintering and bonding the metal mixed powder having excellent lubricating properties to the metal plate. Claims [1] A method of manufacturing a sliding bearing for molding and manufacturing a sliding bearing, the method comprising: applying a bonding material to a non-graphite mixed metal powder containing no graphite on a surface of the metal plate and graphite on the coated non-graphite mixed metal powder; And a bearing material coating step of coating the graphite mixed metal powder in such a manner that the distribution of the particles is gradually increased. &Quot;

According to the invention of No. 10-496655, graphite does not exist between the metal plate and the small-bonded metal layer, so that it does not act as an interfacial bond preventing material, and the interface bonding property is superior to that of the invention of No. 10-286246, The invention is also formed by mixing graphite in a powder form to form a metal powder, so that the metal parts (iron alloy parts) of the three-dimensional network structure in the sintered body are not continuously maintained due to the distribution of the fine solid lubricant and as a result The sintered metal structure becomes discontinuous and nonuniform, leading to weak hardness and strength, making it difficult to use as a bearing for high loads and harsh environments. In particular, when sintering metal powders containing a large amount of graphite in powder form, the graphite powder not only functions as a material that prevents and suppresses sintering but also makes forming and sintering fundamentally difficult, even if sintering is partially. Is very weak in strength and difficult to use for structural purposes. In addition, the fine graphite powder is difficult to uniformly distribute the graphite powder in contact with a portion of the sintered body to form a fragile portion, which may cause breakage of the small-bonded alloy layer during the use of the sliding bearing.

The present invention has been made to solve the above-mentioned problems of the prior art, a steel-based iron-based sintered sliding bearing that can contain a large amount of solid lubricant in the friction layer, while having excellent bonding between the sintered metal and the steel substrate To provide.

Another object of the present invention is to provide a steel-based iron-based sintered sliding bearing having a high load resistance and abrasion resistance is uniform and stabilized sintered metal crystals.

Steel base iron-based sintered sliding bearing according to the present invention to achieve the above object is

Steel substrate; A bonding layer sintered and formed with only iron-based metal powder at a predetermined thickness on the friction side surface of the steel substrate; And a sintering molding on the bonding layer at the same time as the bonding layer, and a sintering-molding friction layer in which the granular solid lubricant having a particle size of 0.04 mm-2 mm in the iron-based metal powder is regularly arranged while maintaining a constant distance between the particles. It characterized by including.

The iron-based metal powder used for the sintering of the bonding layer is 10-30% by weight of copper powder finely divided into 250 mesh or less, among nickel, titanium, silicon, aluminum, cobalt, chromium, manganese or tin. Further containing 0.5-20% by weight of one or more selected metal powder, the iron-based metal powder used for the sintering of the friction layer is 2-20 of one or more metal powder selected from zinc, lead, tin, tungsten, molybdenum It is preferable to contain more weight%.

In addition, the solid lubricant is one or more solid lubricants selected from graphite, molybdenum disulfide (MoS ₂ ) or tungsten disulfide (WS ₂ ), 20 to 60% by volume contained in the friction layer (Y) It is preferable.

The granular solid lubricants 10a, 10b, 20a, and 20b may be arranged in a single layer or a plurality of layers.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the steel-based iron-based sintered sliding bearing according to the present invention.

1 is a perspective view of a flat-type steel-based iron-based sintered sliding bearing according to the present invention, Figure 2 is a perspective view of a bush-type steel-based iron-based sintered sliding bearing according to the present invention, respectively.

Referring to FIG. 1, in order to manufacture the steel-based iron-based sintered bearing, an iron-based sintered layer in which granular solid lubricants 10a and 10b are regularly arranged is formed on the flat steel substrate 13 surface. In addition, referring to Figure 2 in order to manufacture the bush-type steel-based iron-based sintered sliding bearing to form an iron-based sintered layer in which the granular solid lubricant (20a, 20b) regularly arranged on the inner surface of the cylindrical steel base (23). The bush-type steel-based sintered sliding bearing may have a semi-cylindrical shape in addition to the cylindrical as shown in FIG. 2, but the structure of the semi-cylindrical steel-based sintered sliding bearing is cut in half in the cylindrical steel-based sintered sliding bearing. It is the same as, and the manufacturing method is also applicable to the manufacturing method of the cylindrical steel-based iron-based sintered sliding bearing as it will be described below only flat plate and cylindrical steel-based iron-based sintered sliding bearing.

1 or 2, the present invention is characterized in that the bonding layer sintered and formed only with the iron-based metal powders 14 and 24 to a certain thickness on the friction side surfaces of the steel substrates 13 and 23 such as carbon steel or stainless steel ( X) is formed and the friction layer (Y) is sintered and formed simultaneously with the bonding layer (X) on the bonding layer (X), wherein the friction layer (Y) has a particle diameter of 0.04 mm in the ferrous metal powders (14, 24). -2mm granular solid lubricants (10a, 10b, 20a, 20b) are sintered and formed in regular order while maintaining a constant gap between the particles.

Since the bonding layer (X) does not contain any solid lubricants such as graphite, molybdenum disulfide, and tungsten disulfide, the bonding layer X is well bonded at the joining surfaces 12 and 22 with the steel substrate, and the strength and strength of the sintered metal structure. The loadability becomes very large. The iron-based metal powders 14 and 24 used for the sintering of the bonding layer X use iron powder finely divided to 250 mesh or less, thereby densifying the structure of the sintered metals 11 and 21 of the bonding layer. It is preferable that the shrinkage of the bonding layer X during sintering be reduced. By doing so, the bonding between the bonding layer X and the steel substrates 13 and 23 is improved. In addition, it is preferable to add 10-30% by weight of copper powder to the iron-based metal powders 14 and 24 used in the sintering of the bonding layer X to densify the sintered metal structure. In addition, the iron-based metal powder (14, 24) used for the sintering of the bonding layer (X) is 0.5-20 of one or two or more metal powders selected from nickel, titanium, silicon, aluminum, cobalt, chromium, manganese or tin. It is preferable to obtain a sintering temperature suitable for bringing the steel substrates 13 and 23 and the joining layer X into close contact at the joining surfaces 12 and 22 while at the same time adding a weight percent to obtain a high load resistance.

The friction layer (Y) is not only good lubricity, but also good wear resistance and low adhesion to the counterpart. To this end, the iron-based metal powders (14, 24) used for the sintering of the friction layer (Y) is to add 2-20% by weight of one or more metal powders selected from zinc, lead, tin, tungsten and molybdenum. desirable. These metals not only act as metal powders to reduce iron adhesion, but also contribute to the compaction of the friction layer Y and the improvement of wear resistance.

Solid lubricants arranged in granular form in the friction layer (Y) is preferably one or more solid lubricants selected from graphite, molybdenum disulfide (MoS ₂ ) or tungsten disulfide (WS ₂ ). In addition, the particulate solid lubricant (10a, 10b, 20a, 20b) is preferably contained 20% by volume to 60% by volume relative to the total volume of the friction layer (Y). The reason for including a wide range of solid lubricants (10a, 10b, 20a, 20b) in the friction layer is that the solid lubricant is granulated and regularly arranged at regular intervals, the friction layer (Y) This is because the sintering of the iron-based metal powder is not disturbed, and as a result, the sintered metal 11 crystals are not only uniform and stabilized, but also adjacent areas of the solid lubricant particles are blocked, so that a weak portion does not occur. That is, by regularly arranging the granular solid lubricants 10a, 10b, 20a, and 20b in the friction layer Y, since the strength and hardness of the sintered metal in the friction layer Y become very large, a large amount of solid lubricant without softening the structure (10a, 10b, 20a, 20b) will be included.

Granular solid lubricants (10a, 10b, 20a, 20b) arranged in the friction layer (Y) may be formed as a single layer on the surface of the friction layer, but in order to maintain lubricating ability for a long time, two to four layers of multilayer ( It is preferable that it is formed by i). 1 to 4E exemplarily illustrate an arrangement of two-part solid lubricants for convenience.

Hereinafter, a method of manufacturing a steel-based iron-based sintered sliding bearing according to the present invention having the above-described structure will be described in detail with reference to FIGS. 3A to 5.

Figures 3a to 3e is a flow chart showing a method for arranging the granular solid lubricant in the manufacturing step of the flat sliding bearing shown in Figure 1, Figures 4a to 4e is a manufacturing step of the bush-type sliding bearing shown in FIG. Figure 5 is a flow chart showing a method of arranging the granular solid lubricant, Figure 5 shows a flow chart showing a method for producing a steel-based iron-based sintered sliding bearing according to the present invention.

First, referring to FIGS. 3A to 3E and 5, a method of manufacturing a plate-type steel-based iron-based sintered bearing bearing having a two-layer granular solid lubricant arrangement will be described.

Referring to Figures 3a to 3e and 5, in order to manufacture a flat plate steel-based iron-based sintered bearing in accordance with the present invention first of the plate-shaped steel base 13 and the iron-based metal powder 14 and the granular solid Lubricants 10a and 10b are prepared (100, 101, 102, 103). In this case, the granular solid lubricant may be classified by size by tapping artificial graphite particles and the like and then collecting the same size. In addition, by pressing the puncher 17 coupled to the press 18 to prepare a mold capable of forming a pressing molded body of the iron-based metal powder 14 and the granular solid lubricant on the upper surface of the steel substrate. As shown in FIGS. 3A to 3E, the lower mold 15 and the iron-based metal powder 14, which can put the steel base 13 on the steel base 13, can be easily disassembled after pressing. It is preferred to be separated into side molds 16 which can be molded in conformity with the sides.

When the flat steel substrate 13, the iron-based metal powder 14, the granular solid lubricant (10a, 10b) and the mold (15, 16) is prepared, as shown in Figure 3a, the upper surface of the lower mold (15) The steel base 13 is placed, and the iron-based metal powder 14 for forming the bonding layer X is coated on the upper surface of the steel base 13 again.

Next, as shown in FIG. 3B, the granular solid lubricant 10b is arranged on the ferrous metal powder 14 for forming the bonding layer (X). At this time, various methods can be used as a method of regularly arranging the granular solid lubricant 10b at regular intervals, one of which is iron-based first with an eye through which the granular solid lubricant 10b can pass. Put on the metal powder (14), and sprinkled with a granular solid lubricant (10b) on it and sweep it with a brush.

Next, apply the above-described iron-based metal powder 14 for forming the friction layer (Y) on the inner granular solid lubricant 10b (FIG. 3C), and again arrange the granular solid lubricant 10a to form an outer array thereon. do. In this way, only the iron-based metal powder 14 is applied to the joint surface of the steel base 13 at a predetermined thickness, and the metal powder 14 is further applied while regularly arranging the granular solid lubricants 10a and 10b on the outside thereof. 104 is completed.

Next, the iron-based metal powder 14 and the granular solid lubricants 10a and 10b are pressurized by a press combined with a puncher, thereby compressing the molded product of the iron-based metal powder 14 and the granular solid lubricants 10a and 10b on the upper surface of the steel base. It forms (105), puts in a sintering furnace with a steel base and sinters (106).

Hereinafter, a method of manufacturing a bush-type steel-based iron-based sintered bearing bearing having a two-layer granular solid lubricant array will be described with reference to FIGS. 4A to 4E and FIG. 5.

4a to 4e and 5, in order to manufacture a bush-type steel-based iron-based sintered sliding bearing according to the present invention first of the cylindrical steel base 23 and the iron-based metal powder 24 and the granular solid lubricant (20a, 20b) are prepared (100, 101, 102, 103). At this time, the method of granulating the solid lubricant is as described above. In addition, by pressing the puncher (27) coupled to the press 28 to prepare a mold capable of forming a compression molded body of the iron-based metal powder 24 and the granular solid lubricant (20a, 20b) inside the steel substrate (23). . The mold has a core having a side mold 26 into which the steel base 23 can be inserted, and a core capable of forming a cavity in the press-molded body, as shown in FIGS. 4A to 4. It is preferable to separate into the mold 25.

When the cylindrical steel base 23, the iron-based metal powder 24, the granular solid lubricant (20a, 20b) and the mold (25, 26) is prepared, as shown in Figure 4a to 4d, the core mold 25 And assembling the side mold 26, inserting the steel base 23 into the side mold so that the core of the core mold 25 is centered on the cylindrical steel base 23, and then the outer side of the core of the core mold 25 and the cylindrical shape. While applying the iron-based metal powder 24 from the bottom to the space formed between the inner side of the steel substrate 23, the outer arrayed granular solid lubricant 20a and the inner arrayed granular solid lubricant 20b are sequentially disposed around the outer surface of the core. (104). In this case, when the eyes through which the granular solid lubricants 20a and 20b can pass are arranged in a circular shape, the granular solid lubricant arrangement can be easily obtained.

Next, as shown in Figure 4e, the iron-based metal powder 24 and the granular solid lubricant (20a, 20b) by pressing a punch combined with the iron-based metal powder 24 and the inside of the cylindrical steel base 23 A press-formed product of the granular solid lubricants 20a and 20b is formed 105, and together with the cylindrical steel base 23 is placed in a sintering furnace and sintered.

According to the present invention having the above-described configuration, the bonding layer between the sintered metal and the steel substrate can be very excellent, and the friction layer can contain a large amount of solid lubricant, so that the lubricity is excellent even without impregnating a separate wet lubricant. In addition, there is an effect that can maintain the lubrication ability for a long time without adhesion to the counterpart. In addition, according to the present invention, the sintered metal structure is formed very dense, continuous and uniform, not only can withstand high loads, but also has an advantage of having wear resistance.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, the scope of protection of the present invention is not intended to be limited thereto, and the scope of protection of the present invention is set forth in the detailed description of the claims and all equivalent embodiments thereof. It should be interpreted as crazy.

Claims (4)

Steel substrates 13 and 23; A bonding layer (X) sintered and formed by only iron-based metal powders (14, 24) to a predetermined thickness on the friction side surfaces of the steel substrate (13, 23); And Granular solid lubricants (10a, 10b, 20a, 20b) having a particle size of 0.04 mm-2 mm are sintered simultaneously with the bonding layer (X) on the upper surface of the bonding layer (X). The steel-based iron-based sintered material sliding bearing comprising a; sintered friction layer (Y) while being regularly arranged while maintaining a constant interval between the particles. The iron-based metal powders (14, 24) used for sintering the bonding layer (X) are 10-30% by weight of copper powder, nickel, Iron metal powders (14, 24) further containing 0.5-20% by weight of one or two or more metal powders selected from titanium, silicon, aluminum, cobalt, chromium, manganese or tin and used for sintering the friction layer (Y). A steel-based iron-based sintering material sliding bearing, characterized in that it further contains 2-20% by weight of one or two or more metal powders selected from among silver zinc, lead, tin, tungsten, and molybdenum. The method according to claim 1 or 2, The solid lubricant is one or more solid lubricants selected from graphite, molybdenum disulfide (MoS ₂ ) or tungsten disulfide (WS ₂ ), and the friction layer (Y) contains 20% by volume to 60% by volume. Steel-based iron-based sintered sliding bearing The method according to claim 1 or 2, The granular solid lubricant (10a, 10b, 20a, 20b) array is a steel-based iron-based sintered sliding bearing, characterized in that formed in a single layer or a double layer (複 層).

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