JP2004278702A - Oilless chain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the durability of a chain by preventing oil between a bush and a pin kept without oil supply from degrading in high environment. <P>SOLUTION: The pin 3 undergoes a phosphoric acid manganese coating process and phosphoric acid manganese membrane 12 is formed on its surface. In the phosphoric acid manganese membrane, catalyzing reaction does not progress even in high temperature range. The membrane is porous, and iron component of a pin substrate easily combines with oxygen ion on a border plane via the many pores. Therefore, even in high temperature environment, degradation of oil leached from a sintering bush 7 is suppressed, the oil degradation is delayed, occurrence of sludge is suppressed, absorbency and holdability of oil are improved based on the porosity, and oil scattering by centrifugal force or the like is prevented though the oil is held in a low viscosity status where the oil does not degrade. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an oil-free chain having a pin and a bush that slide in contact with each other with oil interposed therebetween in an oil-free environment, and is particularly suitable for being applied to a sintered bush chain using a bush made of an oil-containing sintered material. More particularly, the present invention relates to an oilless chain that suppresses deterioration of oil between a pin and a bush even in a relatively high temperature environment.
[0002]
[Prior art]
Conventionally, a sintered bush chain has a bearing device including a sintered bush and a carburized and quenched pin, and has maintained a smooth bending property of the chain in an oil-free state. However, when the conditions of use are severe, such as a motorcycle chain, the sintered bush chain may cause an adhesion phenomenon between the bush and the pin, or oxidize and wear the surface of the carburized and quenched pin. As a result, the pores of the sintered bush were clogged, and the above-described effects unique to the sintered bush chain could not be sufficiently exhibited.
[0003]
The present applicant applies nickel plating to the pins of the sintered bushing chain, forms a nickel layer on the surface of the pins, and oxidizes the oil leached from the sintered oil-impregnated bush based on the catalytic action of the nickel layer. A grease-like oil film having a higher viscosity is interposed between the pin and the sintered oil-impregnated bush, thereby devising a sintered bush chain having high wear resistance and long life (see, for example, Patent Document 1). ).
[0004]
[Patent Document 1]
JP-B-63-43610 [0005]
[Problems to be solved by the invention]
The sintered bush chain in which the pins are plated with nickel exhibits excellent abrasion resistance particularly in an environment where the operating temperature is around room temperature, and is used for a wide range of applications. Generally, an oil impregnated in the sintered bush of such a chain does not need heat resistance, and an inexpensive mineral oil is used. Even if it is impregnated with a synthetic oil such as an ester type which is excellent in heat resistance and relatively expensive, the abrasion resistance around room temperature is not so excellent (described later), but the sintered bush chain impregnated with the above mineral oil is used. If the operating temperature exceeds 80 to 100 [° C.], problems such as a large evaporation loss of oil, poor bending and abnormal elongation often occur.
[0006]
When improving the abrasion resistance in a high temperature environment, a method of applying an oil having excellent heat resistance is simple and widely applied. However, oils with excellent heat resistance have high viscosity at room temperature, and at around room temperature, it is difficult to obtain the effect of exuding oil from the holes of the sintered bush continuously. Clogging of the tie bush is liable to occur, so that an excellent wear life cannot be obtained. In other words, by applying oil having excellent heat resistance, the wear life in a heat-resistant environment can be extended, but when such a chain is used near room temperature, even if a relatively expensive oil is applied, There is a concern that a problem that the wear life is inferior to the conventional sintered bush chain occurs.
[0007]
By the way, the reason why the sintered bush chain in which the above-mentioned pins are nickel-plated exhibits excellent abrasion resistance is that the oil becomes highly viscous due to the catalytic reaction of nickel and becomes grease-like, and the lubricant is retained between the pins and the bush for a long time. It is understood that it is possible. The factor that largely controls the progress rate of the catalytic reaction is temperature, and the viscosity is increased when the chain is not used, that is, because the catalytic reaction does not proceed, slight frictional heat during driving or repeated sliding (friction) The appearance of the metal active surface due to the above becomes the driving force for the progress of the catalytic reaction. Considering the catalytic function, one function is to increase the reactivity (promoting effect or activation effect), and the other function is to cause only a specific reaction (selectivity effect). ". The function of the nickel plating catalyst is the former "enhancing the reactivity", which means that the alteration such as oxidation of the oil or the sludge (carbide) generation reaction is promoted. In other words, when considered as a single oil, these phenomena are negative factors. If nickel plating is applied to a sintered bush chain pin used at a high temperature exceeding 100 ° C., the catalytic reaction proceeds rapidly, and a large amount of sludge is generated. As a result of earnest research, it has been clarified that is generated early, causing clogging between the pin and the bush, increasing bending torque, and adversely affecting stiffness and wear elongation.
[0008]
In general, the catalytic function of nickel is understood to be a negative factor, and the excellent wear life near normal temperature is due to the extremely small heat input that drives the catalytic reaction, and the progress of the catalytic reaction is extremely small. It was experimentally found that the reason was that the oil became grease-like with little deterioration of the oil. The formation of sludge (carbide) is a by-product of the thermal reaction between the extreme pressure additive in the oil and the metal catalyst. Synthetic oils that are relatively expensive and have excellent heat resistance, even for relatively inexpensive mineral oils However, it is not easy to avoid sludge formation in an environment where a metal having a high catalytic ability such as nickel is present. From such a viewpoint, it is difficult to extend the wear life of the sintered bush chain used in a relatively high temperature environment only by selecting the oil, and it is necessary to find a pin specification (catalyst type) that suppresses the catalytic reaction. is there. In other words, it has been suggested that by finding the optimum pin specification (catalyst type), it is possible to obtain excellent wear resistance in a high-temperature environment even with relatively inexpensive oil.
[0009]
Accordingly, an object of the present invention is to provide an oil-free chain that prevents oil between a bush and a pin held without oil from being deteriorated early even in a high-temperature environment, and that solves the above-described problems. It is assumed that.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a first link (5) in which both ends of two link plates (2, 2) are connected by a pin (3), and two link plates (6, 6). And a second link (10), which is connected by bushings (7, 17), is alternately connected by loosely fitting the pin (3) into the bushing (7, 17), and the space between the pin and the bushing is provided. in the oil-free chain which oil is held (1,1 _5),
The pin (3) is formed by applying a metal phosphate film treatment to form a metal phosphate film (12) on the surface thereof.
It is in the oilless chain.
[0011]
The present invention according to claim 2, wherein the metal phosphate coating is a manganese phosphate coating, and the metal phosphate coating is a manganese phosphate coating (12).
An oilless chain according to claim 1.
[0012]
The present invention according to claim 3 (for example, see FIGS. 1 and 2), wherein the bush (7) is made of a sintered oil-impregnated bearing material.
An oilless chain according to claim 1 or 2.
[0013]
The present invention according to claim 4 (see, for example, FIG. 5), the link between the link plate (2) of the first link (5) and the link of the second link (10) so as to surround the bush (17). An O-ring (20) is arranged between the plates (6), and lubricating oil is sealed between the pin and the bush at the O-ring.
An oilless chain according to claim 1 or 2.
[0014]
【The invention's effect】
According to the first aspect of the present invention, even if the metal phosphate film on the pin surface is in a relatively high temperature range, the catalytic reaction does not proceed and the oil in the bush is consumed while maintaining the properties of the initial oil. The lubricating function is acting, and the metal phosphate metal film is made of a porous material, and even if the metal film itself is stable, the iron component of the pin base is easily bonded to oxygen ions at the boundary surface through the porous material. Accordingly, even under a high temperature environment, the oil deterioration is suppressed, the oil deterioration is delayed, the generation of sludge is suppressed, and the oil absorbency and retention are improved based on the above-mentioned porosity. Despite being kept in a low-viscosity state that does not deteriorate, it prevents the above oil from scattering due to centrifugal force, etc., and even in the non-lubricated state, the appropriate oil is applied to the sliding surface of the pin and bush. Hold for a long time, Even under temperature environment, it is possible to reduce wear between the pin and the bushing, to improve the durability of the chain. In addition, even if the chain is used in a relatively high temperature environment, a relatively inexpensive oil such as a normal mineral oil can be used, and the life of the chain can be extended without increasing the cost. .
[0015]
According to the second aspect of the present invention, the manganese phosphate-based coating is excellent in wear resistance, oil deterioration suppression, oil absorption and retention due to the above-mentioned porosity, and durability of an oil-free chain in a high-temperature environment. Excellent effect can be exhibited.
[0016]
According to the third aspect of the present invention, the metal phosphate film, in particular, the manganese phosphate-based film is hard and has excellent wear resistance, and also has excellent anticorrosion properties while preventing phenomena such as image sticking and galling. It is possible to prevent clogging of the pores of the sintered bush due to the physical characteristics of the above, and to improve the durability of the sintered bush chain, in combination with the above-described prevention of oil deterioration and improvement of the retention. it can.
[0017]
According to the present invention according to claim 4, the lubricating oil between the pin and the bush enclosed by the O-ring, particularly the low-viscosity oil for general mechanical lubrication, is suppressed from being deteriorated by the catalytic reaction as described above. The oil is maintained in an appropriate state for a long time, and the oil gradually leaks while lubricating between the link plates and the O-ring to improve the chain bending property, and the oil amount between the pin and the bush is reduced. Even if it is reduced, the metal phosphate, especially the manganese phosphate-based film, has excellent oil spreadability and holding properties, thereby preventing metal-to-metal contact for a long period of time, so that even under a high temperature environment, The wear of the bush can be reduced, and the durability of the seal type chain can be improved.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the sintered bush chain 1 has the same structure as a pin link 5 in which both end portions of two pin link plates 2 are joined by pins 3 and 3 which have been treated with a manganese phosphate film described later. A roller link 10 in which both end portions of two roller link plates 6 and 6 are joined by bushes 7 and 7 made of sintered oil-impregnated metal. It is configured to be connected to.
[0019]
As shown in detail in FIG. 2, the pin 3 and the bush 7 constitute a bearing device 11 for freely bending the chain 1. The bush 7 has iron as a main component, and copper, nickel, It is composed of a sintered oil-impregnated bearing material appropriately mixed with molybdenum, chromium and the like.
[0020]
The pin 3 is made of a coil material such as carbon steel for machine structure (S-C) such as S45C, chromium molybdenum steel (SCM), or high carbon chromium bearing steel (SUJ). After being sheared, heat treatment such as carburization, quenching, and tempering is performed to give a high surface hardness and a strong internal structure. Further, the surface is polished to a precise outer diameter and a highly accurate surface.
[0021]
Next, the pins that have been subjected to the heat treatment and polishing are subjected to a manganese phosphate coating treatment [Palphos M (IA)]. In the manganese phosphate coating treatment, the pins are degreased, washed with water, and surface-washed, and then immersed in a manganese phosphate solution. On the basis of the manganese phosphate solution, the above-mentioned pin simultaneously performs a corrosion action by free phosphoric acid and a deposition action of a manganese phosphate-based insoluble product due to decomposition, whereby 3 to A relatively thin manganese phosphate-based coating 12 of 5 [μm] is generated. The manganese phosphate-based coating is composed of fine crystals mainly composed of a manganese phosphate salt called Hereaulite represented by (Mn, Fe) ₅ H ₂ (PO ₄ ) ₂ .4H ₂ O.
[0022]
FIG. 3 shows the measurement results obtained by extracting five pins (n = 5) provided with the manganese phosphate-based coating 12 generated as described above. FIG. 3A shows the result of measuring the film thickness by a micrometer according to (after the chemical conversion treatment—after the chemical conversion film peeling) / 2, and FIG. 3B shows the result of (pin weight after chemical conversion—chemical conversion film). The result of measuring the chemical conversion film weight calculated by (pin weight after peeling) / pin surface area is shown. The pin surface area is 5.4599 [cm ² ].
[0023]
As a result, the film thickness from the base to the convex portion is 3.5 to 4.5 [μm], and there is no large variation. In addition, as a result of observing the manganese phosphate coating crystal grain size by the sump method, it was confirmed that porous crystal grains of about 10 [μm] were formed.
[0024]
The manganese phosphate-based coating 12 on the surface of the pin penetrates the pin material, and is generated in a state in which the surface is uniformly even. In addition, since the film is a chemical reaction product film, the dimensional change and weight change before and after the treatment are extremely small, and the treatment temperature is 100 ° C. or less, so that the physical change with respect to the quenched pin does not occur. Almost no.
[0025]
After the above-mentioned manganese phosphate conversion treatment, the pins 3 are washed with hot water and dried. The pin 3 completed in this manner is inserted into the bush 7 made of the sintered oil-impregnated bearing material described above, and the manganese phosphate-based coating 12 on the pin surface and the bush 7 made of the sintered oil-impregnated material are inserted. Sliding contact is made with the peripheral surface 7a. At the time of the sliding contact, the manganese phosphate-based coating 12 has excellent wear resistance, reduces stress by pressure, and is made of a porous crystal, so that it absorbs oil from the sintered oil-impregnated bearing material. -It has good retention and improves the lubrication performance of the oil. In addition, the coating 12, in combination with the bushing 7 made of the sintered oil-impregnated bearing material, prevents the metal from coming into contact with each other, prevents seizure (adhesion), phenomena such as galling, and prevents the sliding portion from sliding. Improve initial familiarity.
[0026]
The chain 1 is used, for example, as a timing chain of an engine. In a use state in such a high-temperature environment, the sliding contact between the pin 3 and the bush 7 has a high temperature of 80 ° C. or more. And a large pressure is applied. However, the above-described improvement of the lubricating function by the oil from the sintered material of the bush 7 based on the oil spreadability and retention by the porous manganese phosphate-based coating 12 and Physical properties such as high hardness, abrasion resistance, peeling resistance, and corrosion resistance of the film are combined to reduce the occurrence of agglomeration and abrasion over a long period of time. Prevent clogging.
[0027]
Furthermore, under the high-temperature environment, the oil from the oil-impregnated sintered material tends to oxidize and deteriorate relatively early, but according to the present invention having the manganese phosphate-based coating 12 on the pin surface. The oil is more resistant to degradation than the conventional nickel or chromium plated. The reason is presumed as follows.
[0028]
First, the catalyst function will be examined in more detail. Almost all elements on the earth have some catalytic action as a simple substance or as a compound, although the catalytic ability varies. FIG. 4 shows the difference in catalytic ability between each element and their compounds (oxides or halides). The greater the number of diagonal lines, the greater the catalytic ability. In general, it is widely known that copper (Cu) has a high catalytic ability, and the application of a copper plate corrosion test as an oil evaluation test requires special attention when selecting a lubricating oil for a copper-based material. Means From FIG. 4, the metals having high catalytic ability are attracting attention because iron (Fe) of No. 26, cobalt (Co) of No. 27, nickel (Ni) of No. 28, and No. 29 concentrated in the periodic table. It is understood that copper (Cu) contains nickel. Also, it can be seen that the catalytic ability of iron, which is the basic material of the chain component, is high.
[0029]
Therefore, in the conventional nickel plating specification, the viscosity of the oil is increased by the catalytic reaction, which contributes to the prolongation of the wear life, whereas in the manganese phosphate specification, the catalytic reaction does not advance, and the properties of the initial oil are not improved. It is considered that the lubricating function works until the impregnated components in the sintered bush are consumed, and that the oil retention by the porous structure is not unnecessarily exhibited.
[0030]
Further, since the manganese phosphate-based coating 12 is made of a porous crystal, the oil leached from the oil-impregnated sintered bearing material is held in the porosity of the crystal, and has a small contact area with oxygen. The partial oxidation is suppressed.
[0031]
Further, the manganese phosphate-based coating itself has a sufficient corrosion resistance stable to oxidation in the environment of the above-mentioned about 80 [° C.], but the coating is relatively thin, having a thickness of 5 [μm] or less. Since it is made of a porous material, the iron component, which is a material of the material, easily binds to oxygen ions at the pin interface, and accordingly, the oxidation of the oil is suppressed.
[0032]
That is, the conventional chain promotes the oxidation of the oil by the catalytic action of nickel or the like to form a sticky grease-like oil film and prevents diffusion by centrifugal force. Even underneath, while suppressing oil oxidation, preventing early deterioration of the oil and maintaining the lubricating performance of the oil, the oil is retained by the porous nature of the film, and the oil is centrifugally applied to the oil. It is a thing which controlled scattering. Thus, even in the above-described severe use in a high-temperature environment, proper oil lubrication is maintained in the chain for a long period of time, and the elongation of the chain is suppressed.
[0033]
Then, to clarify the above, the chain (manganese phosphate film treatment specification pin) 1 according to the present invention, chain subjected to conventional nickel plating (nickel-plated) and 1 _2, the conventional pin the chromizing treatment alms chain: 5 (chromium carbide specifications for example Japanese Patent Publication reference No. 57-60422) and 1 _3, the experimental result of comparison. The conditions of the above experiment are as follows.
[0034]
Each chain 1,1 _2, 1 _3, a sintered bushing chain of the same size of the number JIS60, pins only, nickel plating as described above, chromizing process, that has been subjected or manganese phosphate film treatment Is used.
[0035]
Each chain _1,1 2, _{1 3,} speed 0.95 [m / s], driven by chain tension 2.5 [PS]. Note that the oils are all the same, and ordinary mineral oils in which heat resistance is not particularly emphasized are used. The driving environment of each chain is maintained at 100 [° C.].
[0036]
FIG. 5 shows the results of the actual driving wear test of the sintered bush chain in the above-mentioned 100 [° C.] environment. Chain 1 ₂ nickel plating specification, early flexion torque is increased, the pin by a catalytic reaction, sludge generated is suggested between bushing, continued wear elongation is increased. Very even chain 1 ₃ advantage chromium carbide coating specification is understood by abrasion resistant hard, subsequently bending torque is increased to the nickel-plated, continued wear elongation is increased. The increase in the bending torque and the wear elongation of the chain occur continuously, confirming that the formation of sludge by the catalytic reaction has an adverse effect on the abrasion resistance. On the other hand, the chain 1 of the manganese phosphate specification, the nickel and chromium carbide specifications chain 1 _2, 1 without bending torque increases as _3, inflection from stationary wear zone (transition) is also smooth, It was shown that the appropriate oil was retained between the pin and the bush for a long time due to the effect of suppressing the catalytic reaction. In this case, in particular, it was confirmed that the sintered bush chain impregnated with mineral oil, which does not take special care into heat resistance, has a clear wear life extension effect. That is, as compared with the chain 1 ₂ and the chain 1 ₃ chromium carbide coating specifications of the conventional nickel-plated, the chain 1 of the manganese phosphate film specifications according to the present invention, the driving time in the state elongation of the chain is less Significantly improved, it was proved that the bearing portion between the pin and the bush has little wear and has excellent durability.
[0037]
Generally, the wear life of sliding parts can be extended by applying a manganese phosphate film, but the reason is often qualitatively explained by the oil retention by the porous structure. To examine the retention of the oil due to the porous structure, the result of comparison manganese phosphate film applied pin design sintered bushing chain 1 and the nickel plating applied pin design sintered bushing chain 1 ₂ wear life at room temperature 6 Shown in In the manganese phosphate specification chain 1, it is possible to increase the chain elongation without increasing the bending torque as the drive time elapses. On the other hand, in the nickel plating specification, the bending torque gradually increases slightly, but does not increase more than necessary, and the wear elongation increases after a longer steady wear region. This result indicates that in the nickel plating specification, the viscosity of the oil increases due to the catalytic reaction, which contributes to the prolongation of the wear life, whereas in the manganese phosphate specification, the catalytic reaction does not progress, and the properties of the initial oil It is considered that the lubricating function works until the impregnated component in the sintered bush is consumed, indicating that the oil retention by the porous structure is not unnecessarily exhibited.
[0038]
Note that FIG. 6 shows such a result in comparison with the nickel plating specification, and shows a case where a general quenching and tempering pin to which no surface treatment is applied or a case where a carburizing quenching pin is applied. Compared with a sintered bush chain, there is a high possibility that the effect of applying a manganese phosphate coating is obtained. This is also confirmed by the reproducibility, and it is again shown that the application of nickel plating to the pin is effective at around normal temperature, and the manganese phosphate specification can suppress the catalytic reaction, and it is relatively difficult to exceed 80 to 100 ° C. It is suggested that the pin is effective as a chain pin used at a high temperature.
[0039]
That is, in an environment where a catalytic reaction is easy to function and a sufficient heat input is ensured (under a relatively high temperature environment), the pin 1 of the manganese phosphate film specification is made of nickel plating, chromium carbide film, hard chromium film. It became clear that the abrasion resistance was excellent and the wear life could be extended as compared to each pin which had not been plated and had no surface treatment.
[0040]
In the above-described embodiment, the pin was treated with a manganese phosphate film. However, the present invention is not limited to this. Other metal phosphates such as a tin phosphate film treatment (Palmet B-43 treatment) and a zinc phosphate film treatment were used. Even when the coating treatment is performed, an action similar to that described above is obtained, but the manganese phosphate coating treatment is most excellent in hardness, abrasion resistance, porosity and the like. The metal phosphate film is a film composed of a crystalline phase of a metal phosphate, and the metal phosphate film treatment is synonymous with the phosphate film treatment.
[0041]
Further, the pin that has been subjected to the phosphoric acid film treatment is not limited to being combined with a sintered bush, but can be similarly applied to other oil-free type chains, for example, a seal type chain. That is, as shown in FIG. 7, the seal type chain ₁₅ is composed of two pin link plates 2 and 2 having both ends joined by the above-mentioned manganese phosphate film-treated pin 3 and two pin links 2 and And a roller link 10 in which both end portions of the roller link plates 6 and 6 are connected by a pipe-shaped steel bush 17. A steel roller 19 is rotatably fitted to the bush 17 in a freely rotatable manner. ing. The space between the pin 3 and the bush 17 constituting the bearing portion is filled with lubricating oil such as grease or ordinary mineral oil, and is sandwiched between the plates 2 and 6 so as to surround the bush 17. An O-ring 20 is arranged and the lubricating oil is sealed therein. The bush 17 is fixed so as to protrude from the roller link plate 6 by a predetermined amount, and the amount of compression of the O-ring is regulated by the protruding portion.
[0042]
To the chain 1 ₅ of the present seal type, by using a pin 3 which has been subjected to the above-mentioned manganese phosphate film treatment, similarly, to prevent premature oxidative degradation of the lubricating oil, improve the wear resistance of the chain I can do it. In addition, a solid lubricant such as graphite or molybdenum disulfide is interposed between the sintered bush 7 and the pin 3 or is mixed with the lubricating oil of the seal type chain to be used, so that wear resistance is reduced. Performance can be further improved.
[0043]
There are many types of oils, which tend to be more expensive and more heat-resistant. However, in most cases, only the lubricity in a heat-resistant environment is improved, and the room-temperature characteristics are deteriorated. The present invention achieves an extended wear life in higher temperature environments by finding optimal pin specifications even with relatively inexpensive oil. In other words, the effect of price increase due to improvement in heat resistance of oil is relatively large in many cases, whereas the manganese phosphate-based coating according to the present invention is applicable in a relatively high temperature environment at the same cost as conventional nickel plating. it can.
[Brief description of the drawings]
FIG. 1 is a partially sectional plan view showing a sintered bush chain to which the present invention is applied.
FIG. 2 is a cross-sectional view of the pin and the bush portion.
FIGS. 3A and 3B show the results of measuring a manganese phosphate-based coating of a pin, wherein FIG. 3A shows the thickness of the coating and FIG. 3B shows the measurement of the coating weight.
FIG. 4 is a diagram showing catalytic ability of elements and compounds thereof.
FIG. 5 shows the results of actual driving wear tests performed on a sintered bush chain using a conventional pin and a sintered bush chain using the pin according to the present invention in a high temperature (100 ° C.) environment. FIG.
FIG. 6 is a view showing the results of actual driving wear tests performed on a sintered bush chain using nickel pins and a sintered push chain using pins according to the present invention in a normal temperature environment.
FIG. 7 is a partially sectional plan view showing a seal type chain to which the present invention is applied.
[Explanation of symbols]
1,1 ₅ oil-free chain (sintered bushing chain, seal type chain)
2 (pin) link plate 3 pin 5 first (pin) link 6 (roller) link plate 7 sintered bush 12 metal phosphate (manganese) coating 17 bush 20 O-ring

Claims (4)

A first link in which both ends of two link plates are connected by pins and a second link in which two link plates are connected by bushes are alternated by loosely fitting the pins into the bush. And an oil-free chain in which oil is held between the pin and the bush,
The pin has been subjected to a metal phosphate coating treatment to form a metal phosphate coating on its surface,
Oil-free chain. The metal phosphate coating is a manganese phosphate coating, and the metal phosphate coating is a manganese phosphate-based coating.
The oilless chain according to claim 1. The bush is made of a sintered oil-impregnated bearing material.
The oilless chain according to claim 1. An O-ring is arranged between the link plate of the first link and the link plate of the second link so as to surround the bush, and the O-ring is filled with lubricating oil between the pin and the bush. Do,
The oilless chain according to claim 1.

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