JPS61144469A - Sliding surface opposed structure - Google Patents

Abstract

PURPOSE:To improve wear-resistance and scuffing-resisting property by setting a sliding surface where hard particles are uniformly dispersed and buried against a sliding surface to which mixed powder composed of high chrome cast iron powder, Mo powder and so on is plasma-sprayed. CONSTITUTION:Hard particles 5 such as fine Sic particles or the like are uniformly dispersed and buried in the interior of an oil sump groove portion 3 of a specified pattern, and the surface of a plateau portion 4 surrounded by the groove portion on one surface formed by iron steel or cast iron. Mixed powder formed by mixing mixed powder of high chrome cast iron of a specified composition and Fe-C-Cr alloy and Mo powder at a specified ratio or mixed powder further mixed with self-welding alloy powder is plasma sprayed to the other sliding surface. It is important to minimize the average particle size of hard particles, and to specify the buried-in area rate of hard particles, the occupied area rate of the plateau portion and the maximum surface roughness of the plateau portion.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to sliding surface pair structures of relative sliding members that require wear resistance and scuffing resistance, particularly for internal combustion engines, compressors, pumps, etc. The present invention relates to a sliding surface pair structure in which the sliding surfaces of a functional component such as a cylinder (including a cylinder sleeve, a cylinder liner, a cylinder block, etc., the same applies hereinafter) and a piston ring face each other.

(Prior art) Internal combustion engines have become more efficient in recent years, and at the same time, in order to prevent pollution and save energy, the load on functional parts such as piston rings and cylinders is increasing, and the required quality is becoming more sophisticated. It becomes. In other words, these functional parts are strongly required to have wear resistance and scuffing resistance that can withstand a reduction in lubricating oil consumption (LOC) under conditions of high temperature and high load, as well as weight reduction and reduction of friction loss. In order to meet this requirement, properties between sliding surfaces, in other words, more desirable combinations of relative sliding members or compatible sliding surface pair structures are being pursued.

JP-A-52-138797 discloses a wear-resistant treatment method for one cylinder liner sliding surface that meets the above requirements. According to this method, a slurry or paste containing SiC is used to form spiral grooves on the sliding surface of a cylinder etc. using a roughing tool, and SiC particles are embedded in the grooves. Wear-resistant treatment consists of a process of scraping off the peaks of the particles, removing sharp corners of the particles, pushing in the protruding particles, and, if necessary, finishing lapping with a honing shoe containing finer particles than in the previous process. It will be done. This treatment method has been put to practical use in some cylinders or cylinder liners made of cast iron or steel, and it shows excellent performance in terms of the wear resistance of the cylinder itself, and is also cost-effective compared to special wear-resistant cast iron or chrome-plated cylinders. It is highly acclaimed because it enables a large reduction in weight, and when applied to thin-walled steel cylinders, makes it possible to reduce weight and increase the bore within the range of use of ready-made engine blocks.

(Problem to be solved by the invention) However, although cylinders that have undergone this treatment exhibit outstanding performance in terms of wear resistance of the cylinder itself, it also causes significant wear on the mating piston ring. Due to its flaws, the current situation is that it has no choice but to be limited in its applicability under the harsh operating conditions of modern high-performance engines.

Therefore, in order to expand the range of application of the cylinder subjected to the above-mentioned treatment, it is necessary to develop a sliding surface pair structure that satisfies the above-mentioned required characteristics.
That is, there is a desire to develop piston rings that are compatible with each other and to improve the cylinder itself, but at present no desirable combination has been found.

(Means and effects for solving the problems) The present invention has the following features:
A sliding surface pair structure that satisfies the above-mentioned requirements, eliminates the conventional problems, and fully utilizes the advantages of the sliding surface embedded with SiC particles, and in particular, specifies fine SiC particles. High chromium cast iron of a specific composition and Fe-
A sliding surface made of a combination of sliding surfaces (B) that have been plasma sprayed with a mixed powder made by mixing a mixed powder with a C-Cr alloy and Mo powder in a specific ratio, or a mixed powder made by further mixing a self-fluxing alloy powder. It attempts to provide a face-to-face structure.

The first feature of the present invention (hereinafter referred to as the first invention) is that oil sump grooves in a specific pattern are arranged in a base material made of steel or cast iron, and the area ratio of 3 to 12% is uniformly distributed inside the grooves and on the plateau. A sliding surface (A) having dispersed and buried hard particles with an average particle size of 5 to 20 μm and a smoothed upper surface, high chromium cast iron powder with a particle size not coarser than 74 μm, and Fe-C.
- Mix with Cr alloy powder to change the composition by weight from C3.0 to
7.0%, Cr25-55%, and the remainder is substantially F.
65 to 95% by weight of mixed powder as e and further particle size of 74μ
It has a sliding surface pair structure consisting of a sliding surface (B) having a thermal sprayed layer formed by plasma spraying a mixed powder mixed with 5 to 35% by weight of Mo powder whose particles are not coarser than m.

The second feature of the present invention (hereinafter referred to as the second invention) is that oil sump grooves of a specific pattern are arranged in a base material made of steel or cast iron, and the area ratio of 3 to 12% is uniformly distributed inside the grooves and on the plateau. A sliding surface (A) having hard particles with an average particle diameter of 5 to 20 μm dispersed and buried therein and having a smoothed upper surface, high chromium cast iron powder with a grain size not coarser than 74 μm, and Fe-
By mixing with C-Cr alloy powder, the composition becomes C3,0 by weight ratio.
~7.0%, 65-85% by weight mixed powder containing 25-55% Cr and the balance being substantially Fe, particle size 74μ
5 to 25% by weight of Mo powder that is not coarser than m and the particle size is 7
It has a sliding surface pair structure comprising a sliding surface (B) having a sprayed layer formed by plasma spraying a mixed powder mixed with 5 to 25% by weight of a self-fluxing alloy powder having grains not coarser than 4 μm.

As a result, the first and second inventions configure the sliding surface (A) so as to fully exhibit its characteristics without impairing the wear resistance of the sliding surface (A) itself. The sliding surface (B) is configured to significantly reduce the wear of the sliding surface (B) as a material (for example, a piston ring), and by combining these configurations, the wear characteristics of both sliding surfaces can be improved. A sliding member having a sliding surface (A) is used because it is possible to achieve balance, reduce lubricating oil consumption in internal combustion engines, prevent blow-pipe and scuffing, maintain engine performance, and extend the life of the engine. For example, the range of application of cylinders can be expanded.

The specific configuration of the present invention will be described below. Fig. 1 is a vertical cross-sectional view of the cylinder liner that constitutes the sliding surface (A), in which (1) is the cylinder liner, (2) is the sliding surface which is the inner peripheral surface of the cylinder liner, and Fig. 2 is the main part. Fig. 1 is an enlarged cross-sectional view of section A in Fig. 1 showing the sliding surface (A) of the cylinder liner (1) to which the invention is applied; (4) is a smooth sliding surface surrounded by the core oil reservoir groove (3) (hereinafter referred to as the plateau portion); (5) is the core oil reservoir. Hard particles buried inside the groove and in the plateau. FIG. 3(a) shows the cylinder liner sliding surface (A) immediately after the hard particles (5) are buried inside the oil sump groove and in the plateau. Fig. 3(b) is a partially enlarged sectional view corresponding to Fig. 3(a) after finishing processing, and Fig. 4 shows the stylus attached to the cylinder liner. A cross-sectional curve obtained by moving the inner circumferential surface in the axial direction or a roughness curve with a cutoff value of 2.5 m/m or more (6) (JI
S BO601-1970) is a drawing illustrating a part of SBO601-1970), in which an arbitrary straight line parallel to the average line of the cross-sectional curve (6), that is, a base line (7) is a certain standard length, for example, 2.5 m. /m), the length of cutting the substantial part of the curve (6) is 1. , Il, , l, , β4,15, the plateau rate (occupancy ratio of the plateau portion) at the base line (7) of the curve (6) is determined by the following equation.

<%) Therefore, in order to obtain a cylinder liner having one sliding surface (A) according to the present invention, roughing is performed using a polishing liquid mixed with a slurry or paste containing hard particles such as StC. It is obtained by rotating and reciprocating the inner peripheral surface of the cylinder liner (1) using a tool or honing shoe. That is, by this processing, the hard particles (5) are formed into oil sump grooves (
3) is buried in the interior of the core oil reservoir groove (3) and the plateau (4), and at the same time, a substantially rhombic plateau (4) surrounded by the core oil reservoir groove is formed (second (See Figures 3(a) and 3(b)). In this case, only the oil sump groove (3) is formed using a relatively low tool pressure in the initial process, and the pressure is increased in the next process to increase the depth and width of the oil sump groove (3) and at the same time nucleate the hard particles. It is also possible to use a known method of embedding it inside the oil sump groove (3) and the plateau (4). When a two-step operation is used as described above, in the second step, the protrusions on the inner circumferential surface of the cylinder liner between the leading edges are scraped off, the sharp edges of the hard particles are removed, and the protruding hard particles are further grooved. is pushed into the interior and plateau area. In any of the above methods, the plateau part (4) and the hard fine particles (5
) In order to obtain a cylinder liner (FIG. 3(b)) in which the upper surface of the sliding surface (A) constituted by The surface is finished by lapping or honing using a polishing liquid mixed with slurry or the like, or it is polished by a honing shoe with a fine-grained grindstone to remove the unevenness from the previous process. It is then washed and degreased. Here, the depth and width of the core oil reservoir groove (3), the embedded area ratio of the hard particles (5), the occupied area ratio of the plateau part (4), etc. are determined by the material of the base material, the size of the hard particles, the tool pressure, and the rotation. It is governed by factors such as number, processing speed and time. The selection of these factors will be described later.

The inventors of the present invention focused on the fact that the cylinder liner produced according to a known method accelerates the wear of the mating piston ring despite its own excellent wear resistance and scuffing resistance, and diligently investigated the cause of this. Result, sliding surface (A)
further refine the average particle size of hard particles such as SiC dispersed and buried in The inventors discovered that this is particularly important in relation to the sliding surface (B), and created a structure for one of the sliding surfaces (A) that is a common feature of the first and second inventions.

The hard particles on one sliding surface (A) according to the present invention are SiC+Alz03. Crz03. Although a single particle selected from the group consisting of Si3N4 can be used,
It is desirable to use SiC particles because of the property that the hard particles are embedded so as to be firmly held in the base material, that is, the embeddability, and the property that the hard particles are not crushed during processing, that is, the crush resistance. It is preferable for hard particles such as SiC to have sharp corners as much as possible in terms of embedding efficiency (i.e., the ratio of embedding depth to processing pressure), and the particle size depends on the material of the base material to be embedded, tool pressure, etc. This is related to the wear resistance and scuffing resistance of the cylinder liner (sliding surface A).
), it is necessary to limit the average particle size after embedding to 5 to 20 μm. That is, if the average particle diameter is less than 5 μm, the cylinder liner itself will lack wear resistance, and if hard particles exceeding 20 μm are embedded, dispersibility (density) will be lacking while maintaining the embedded area ratio (3 to 12%). When the relatively soft base material gradually wears out, the local surface pressure of the hard particles becomes high (which may induce scuffing and accelerate wear of the mating piston ring. The more preferable range is 7 to 15 μm. Therefore, it is important that the hard particles have an appropriate particle size and are embedded finely and uniformly into the cylinder liner sliding surface.

The reason for limiting the area ratio of hard particles embedded in the sliding surface of the cylinder liner is that if it is less than 3%, the wear resistance and scuffing resistance of the cylinder liner itself will be insufficient, and if it exceeds 12%, the wear of the mating piston ring will increase. 3 to 1 because balanced wear is not achieved between the sliding surface and the structure.
The range shall be 2%. A more preferable range is 5 to 10%. Occupancy area ratio of the plateau part surrounded by the spiral cross groove (
Regarding the plateau rate), the baseline with a plateau rate of 1.0% (
It is preferable to set it as 75-95% at the depth of 2 micrometers (h) from 8). The reason for this limitation is that the plateau rate is 75%.
If it is less than 95%, the number of oil sump grooves will inevitably increase, resulting in an increase in O and C, which is undesirable.On the other hand, if it exceeds 95%, the number of oil sump grooves will decrease, increasing the tendency for scuffing. A more preferable range is 80 to 90%. In addition, the reason why the plateau rate was set to 2 μm from the base line (8) with a plateau rate of 1.0% was to optimize the amount of oil retained on the cylinder sliding surface at the initial stage of engine break-in, and to minimize O and C. This is because the amount of wear required to reach a plateau rate of 75 to 95% (pressure receiving area of 75 to 95%) is approximately 2 μm or less, and the time required for initial break-in operation can also be shortened (see Figure 5). . The maximum surface roughness of the plateau portion of the cylinder is important as a surface quality at the initial stage of engine running-in; if it is less than 3 μm, the surface will lack oil retention and may cause initial scuffing;
If it exceeds m, the local surface pressure will increase and this will also cause initial scuffing, so it is limited to a range of 3 to 7 μm. The preferred range is 3 to 5 μm. In addition, the base material is STKM or STK.

Steel such as STC, 5O5-TK, 5Cr-TK, SCM-TK, or any type of cast iron can be used.

In order to obtain one sliding surface (A) that satisfies the above requirements, the first step (grooving and
In the embedding process, the cylinder sliding surface was honed using a slurry containing 5iC particles with an average particle size of 120 to 280 mesh at a honing shoe pressure of 0.5 to 2.0 kglon.
”, rotation speed x stroke x time: 50~25Orpm
/min x 20-60 times/1 line x 1-3 minutes, and in the second step (finishing)
A honing shoe pressure of 0.5 to 2.0 kg/cm was used using a slurry containing SiC fine particles with an average particle diameter of mesh.
”, rotation speed x stroke x time: 50 to 250 rpm
The cylinder sliding surface may be finish honed under the conditions of /win x 20 to 60 times/l1in x 1 to 3 minutes.

In this way, the surface state as shown in FIG. 3(a) after the first step and as shown in FIG. 3(b) after the second step is obtained, but the processing conditions of the first step and the cylinder base material Depending on the material, especially its homogeneity, S
In some cases, the iC particles exhibit a surface state in which they are buried in the cylinder base material.

In the case of such a surface condition, most of the primary sliding surface of the cylinder is occupied by the relatively soft, low-melting point base material, which may induce scuffing under severe conditions such as boundary lubrication. Although there is a possibility that the surface state shown in FIG. 3(b) and the total embedded area ratio of SiC fine particles are 3 to 1
Compared to 2%, if it is 30% or less, there is no actual harm even if the surface condition shown in FIG. 3(C) is present.

Next, the other sliding surface (B) according to the present invention will be described.

The common features of the sliding surface (B) are high chromium cast iron powder and Fe.
- Plasma spraying a mixed powder of a mixed powder with a c-Cr alloy powder and further a mixture of Mo powder.
The sliding surface (B) is
Dramatically improves compatibility with the sliding surface (A), moderately balances wear on both sides, and improves scuffing resistance, thereby further enhancing the durability and reliability of internal combustion engines. be.

What is high chromium cast iron? “Steel Materials Handbook,” June 30, 1962.
Based on the ingredients shown in Table 22.26 and the explanation below the table on page 865 of "Japanese Edition", the sliding property is rich in Cr content and has chromium carbide uniformly dispersed in the cast iron matrix. It is used as a component of member (B). In other words, the high chromium cast iron thermal spray layer is finely dispersed in the form of stable carbides, and has excellent heat resistance and wear resistance, as well as corrosion resistance, especially resistance to dilute sulfuric acid corrosion. The high chromium cast iron thermal spraying component does not accelerate the wear of the mating material (cylinder) as compared to when Fe--Cr alloy powder is thermally sprayed alone. In addition, high chromium cast iron exhibits a white cast iron structure in the cast state and has excellent crushability, making it easy to produce powder, and it is also available at a lower price than carbide, Fe-C-Cr alloy powders, etc. There are many advantages to plasma spraying as a mixed powder. Furthermore, the high chromium cast iron powder applied to the sliding surface (B) is not limited to ground powder, but atomized powder may also be used. However, in the case of high chromium cast iron, there is a limit to the Cr content due to cast iron melting, etc., and single thermal spraying of high chromium cast iron tends to increase wear on piston rings.

Therefore, Fe-C- has a higher Cr content than high chromium cast iron.
By plasma spraying a mixed powder containing Cr alloy powder together with Mo powder, which has excellent scuffing resistance, the drawbacks of each are compensated for and a sliding surface (B) that is extremely compatible with the sliding surface (A) can be obtained. It will be done.

As Fe-C-Cr alloy powder, Fe-C with medium carbon or higher
r (ferrochrome) alloy powder, especially high carbon Fe-Cr (
Ferrochrome) alloy powder is preferable.

Next, the reason for the composition limit of the mixed powder of high chromium cast iron powder and Fe-C-Cr alloy powder and Mo powder will be described.

C is the main component of high chromium cast iron and Fe-C-Cr alloy.
r is an element that has a strong carbide-forming action and fixes most of the carbon contained therein as carbides such as Cr, C3°Cr, C, etc. These carbides are uniformly and finely dispersed in the base of each cast iron and alloy, and are also included as an intervening phase in the mixed sprayed sliding surface (B), and are effective against the hard particles of the sliding surface (A). It has an important effect of imparting wear resistance and scuffing resistance. C in this mixed powder
If the r content is less than 25%, the amount of carbide in the sliding surface (B) will be insufficient and the wear resistance and scuffing resistance of the piston ring itself will decrease, and if it exceeds 55%, the wear resistance of the piston ring will deteriorate. Although this improves the performance, it also accelerates the wear of the mating cylinder. Therefore, the Cr content should be in the range of 25 to 55% by weight, more preferably 30 to 55% by weight, and most preferably 35 to 50% by weight.

Most of C should be kept within a range where most of it combines with Cr in the cast iron or alloy to form the chromium carbide, and for this purpose, the C content in the mixed powder should be 3 to 7% by weight.
Preferably it is in the range of 4 to 6% by weight. That is, if the C content is less than 3%, the absolute amount of carbides produced will be insufficient, resulting in insufficient wear resistance, and if it exceeds 7%, free carbon ( Since there is a risk that graphite (graphite) may be generated in high Cr cast iron, it is desirable to keep the content to 7% or less. In addition to the above-mentioned C and Cr, other components of the cast iron material, such as Si, Mn, P, S, Go, V, Ni, etc., may be contained in small amounts within a range that does not impair the above-mentioned characteristics.

Next, the reason why the mixed powder of high chromium cast iron powder and Fe-C-Cr alloy powder is limited to a particle size of 74 μm or less will be described.

Generally, thermal sprayed layers have pores, which act as oil pockets and contribute to scuffing resistance. However, when the pores become coarse, the self-bonding force between the sprayed particles is insufficient, causing the sprayed particles to fall off during sliding. The piston ring and mating cylinder are interposed between the moving surfaces, resulting in wear of the piston ring and the mating cylinder. Therefore, from the viewpoint of lubricant retention and wear resistance of both sliding surfaces, the porosity, pore size, and distribution state should be appropriately controlled. Since it is largely influenced by the particle size of the thermal spraying material, especially the thermal spray powder, the particle size was limited to 74 μm or less in consideration of the above points.

Furthermore, the workability of thermal spraying and the properties of the thermal spray layer are also affected by the particle size of the thermal spray powder.If the powder becomes too fine, the fluidity will decrease and it will be difficult to stably supply the powder to the thermal spray nozzle. is preferred.

Mo is further mixed and sprayed on the other sliding surface (B) in the first aspect of the present invention. Although thermal spraying of Mo alone has excellent scuffing resistance, it has poor abrasive wear resistance and poor oxidation resistance, so the bonding force between Mo particles in the sprayed layer is weak, resulting in defects that tend to cause peeling between the eyebrows. There is.

In the present invention, Mo powder is used for high chromium cast iron and Fe-C
Since the mixed powder with the -Cr alloy powder is mixed and sprayed by the plasma spraying method, each sprayed particle coexists in a molten state, and the low oxidation resistance of the Mo particles themselves is alleviated.

Mo powder may be a single powder, but if you use Mo granulated powder in which Mo fine particles are bound with an organic or other binder,
A sprayed layer in which Mo particles are finely dispersed is obtained, and it is expected that the bonding strength between the sprayed particles will be improved. Moreover, single powder M
Ultrafine powder, which cannot be used due to its sublimation property, can be used by granulating it to improve uniform distribution. 1st
The reason why the Mo powder on the other sliding surface (B) in the invention and the second invention is made to have a particle size of 74 μm or less is because if the particle size is coarser than 74 μm, the surface porosity of the sprayed layer will increase and the abrasive wear resistance will deteriorate. This is because the distribution of land is impaired.

The particle size of the Mo powder is preferably 5 μm or more.

Next, regarding the reason for the limit on the amount of Mo powder mixed on the other sliding surface (B) in the first invention, if the amount mixed is less than 5%, Mo's unique scuffing resistance will be reduced due to the improvement in the bonding strength between each sprayed particle. Effects such as resistance to abrasive wear between moving surfaces are not exhibited, and if it exceeds 35%, the oxidation resistance of the sprayed layer deteriorates, resulting in a rapid decrease in interparticle bonding force during internal combustion engine operation. This causes abrasive wear. Therefore, the amount of Mo powder mixed is in the range of 5 to 35% by weight,
Preferably it is in the range of 10 to 30% by weight. On the other hand, the amount of mixed powder of high chromium cast iron powder and Fe-C-Cr alloy powder is limited by the Cr and C content in the above-mentioned mixed powder and also the Cr and C content in the sprayed layer.
o It is 65 to 95% by weight, preferably 70 to 90% by weight, depending on the amount of powder mixed.

The amount of high chromium cast iron powder in the mixed powder is preferably 25 to 45% by weight. The other sliding surface (B) in the second invention is made of high chromium cast iron powder and Fe-C-Cr.
It is characterized by a combination of mixed powder with alloy powder, Mo powder, and self-fluxing alloy powder.

Self-fluxing alloys generally contain B and/or Si as self-fluxing components, and N i+ C01F er and N as main components.
The remainder contains at least one type of i-Cr.

An example of its composition is "Metal Surface Treatment Handbook, Revised New Edition" 97th
It is shown on page 0. When a self-fluxing alloy powder containing the above-mentioned NLCo, Cr, etc., which generally has good heat resistance and oxidation resistance, is mixed and sprayed with the powder, high chromium cast iron and F
The particles mixed with the e-C-Cr alloy and the Mo particles are firmly dispersed and held by the self-fluxing alloy, and as a result, the strength of the sprayed layer is significantly increased. In addition, when a self-fluxing alloy is used, the adhesion strength with the base material is improved, the porosity is controlled to a low level, and when the sliding surface is processed and finished after thermal spraying, an extremely smooth upper surface can be obtained, making it possible to improve the adhesion strength in the initial stage of sliding. Obtain results that are compatible with the mating material.

As mentioned above, self-fluxing alloys have high oxidation resistance and can also improve the strength of the sprayed layer and the adhesion strength to the base material, so they improve the performance of piston rings, etc. under the operating conditions of internal combustion engines with high heat loads and severe oxidation. is improved.

The amount of self-fluxing alloy powder is determined by taking into account the above characteristics as well as the relative proportion with other mixed powders, especially high chromium cast iron powder and F
The content is set in the range of 5 to 25% by weight so as not to impede the wear resistance provided by the mixed powder with the e-C-Cr alloy powder. If the amount of self-fluxing alloy powder mixed is less than 5%, the above effect will not be sufficient, and if it exceeds 25%, high chromium cast iron powder and Fe-
A more preferable range is 10 in which the amount of the mixed powder with the C-Cr alloy powder, that is, the amount of chromium carbide produced and the mixing ratio of the Mo powder is relatively reduced and the compatibility with the sliding surface (A) is deteriorated.
~25% by weight. The other sliding surface in the second invention (
B) combines and integrates the characteristics of each mixed powder, and at the same time complements the shortcomings of individual powders, and the compatibility with the sliding surface (A) is improved by the coexistence of each particle. It is something. The mixing amount of each powder is limited for the same reason as the other sliding surface (B) in the first invention, but due to the relationship between the powders, high chromium cast iron powder and Fe-C-
The mixed powder with the Cr alloy powder is 65 to 85% by weight, the Mo powder is 5 to 25% by weight, and the self-fluxing alloy powder is 5 to 25% by weight.

Therefore, more preferable ranges are 65 to 80% by weight and 10% by weight, respectively.
-25% by weight, 10-25% by weight. When the particle size of the self-fluxing alloy powder becomes coarser than 74 μm, particle melting during thermal spraying is insufficient, resulting in enlargement or coarsening of pores, deterioration of interparticle bonding strength, deterioration of adhesion with the base material, and various components in the thermal spray layer. This results in undesirable results such as non-uniform dispersion. The preferred particle size is 10μm
If the particles are finer than this, the self-fluxing alloy will dissolve excessively during thermal spraying, and the physical properties of the thermal sprayed layer will deteriorate. When the self-fluxing alloy powder is mixed and sprayed in this way, thermal oxidation resistance, coating density, interparticle bonding strength, adhesion to the base material, and workability are improved, and a finished surface with more stable sliding properties can be obtained. When sprayed with a mixture of self-fluxing alloy powder, the porosity is 5 to 15% and the pore size is 5.
The pores are adjusted to be smaller than μm, and the pores are evenly distributed.

The other sliding surface (B) in the first and second inventions can obtain considerable adhesion strength even when directly sprayed onto cast iron or steel as the base material, but when used under more severe conditions. M as a base thermal spray.

-Ni alloy (75% Mo) or the like may be used.

Example 1 88φ (outer diameter) m/mm processed to specified dimensions and degreased and cleaned
mX36φ (inner diameter) m/mx178 m/m (length)
The circumferential surface of a steel cylinder liner (material: equivalent to STEM material) was honed using a slurry containing SiC particles with an average particle size (220 mesh), and a honing shoe pressure of 1.0 kg/
Mouth 2, rotation speed x stroke x time: 80 rpm + /a
kin Using slurry,
Honing shoe pressure 1.0 kg/C11l”
, rotation speed x stroke x time: 80rpa+/n+1n
The inner peripheral sliding surface was polished and finished under the conditions of X30 times/m1nXZ minutes, and finally washed with kerosene and degreased by a conventional method.

The sliding surface of the cylinder liner obtained by this process (A
), SiC particles are uniformly embedded in the spiral cross grooves and plateau portions with an embedded area ratio of approximately 7%, and the occupied area ratio (plateau ratio) of the approximately rhombic plateau portion surrounded by the cross grooves is approximately 82%. The maximum surface roughness of the plateau portion is approximately 4μ
It was m. On the other hand, 86φm/m (outer diameter) x 2.5m
/m (width) x 4, Orn/m (thickness) in a groove cut into the outer peripheral surface of a spheroidal graphite cast iron piston ring (TOP ring).

- High chromium cast iron powder and Fe-C having the composition and particle size shown below after being thermally sprayed with Ni-based alloy to a thickness of about 20 μm
-A mixed powder obtained by mixing a mixed powder with -Cr alloy powder and a Mo powder (first invention), and a mixed powder obtained by further mixing Ni-Cr self-fluxing alloy powder into the first invention (second invention), respectively.
ll! Plasma spraying was carried out using a TC03M gun, and the sample piston was polished so that the thickness of the mixed sprayed layer was 180 μm, the grooves were completely filled, and the surface roughness was 0.5 to 1.5 μm. It was made into a ring. Also, 2nd, o
A Cr-plated ring was used as the il ring. As a comparative example, the cylinder liner was made of the same material and subjected to the same treatment as in the example, and the piston ring was plated with hard chromium and subjected to various types of plasma spraying.

The composition and particle size of the thermal spray powder used in each example and comparative example are as follows.

・High chromium cast iron crushed powder 35.4%Cr, 5.87%G, 1.33%Si
, 0.24% Mn, balance Fe and impurities.
Grind with a ball mill to 3 μm or less and 20 μm or more
e-C-Cr alloy powder JIS G2303 FCrH+ 63# m or less 6
8.4%Cr, 6.65%G, 0.14%Si balance F
e・Ni-Cr self-fluxing alloy powder JIS H8303MSFNi 631t m or less 1
6.9%Cr, 3.2%B, 3.5%St, 0.6
6% C22, 8% Fe, balance Ni.

・Mo powder 99% or more MO 53 μm or less ・Mixed powder of comparative example: CrzC3 powder 44 μm or less: Ti(h powder 53 μm or less ・Hard chrome plating of comparative example: Plating thickness 0.3 m/+
Hardness HV980 Table 1 shows piston rings (sliding surface B) according to the present invention.
and the mixing ratio of each sprayed powder for a piston ring as a comparative example, the C and Cr content of the mixed powder of high chromium cast iron powder and Fe-C-Cr alloy powder, the surface porosity of each sprayed layer,
Indicates the surface roughness and surface hardness of the finished surface. The test engine and test conditions were as follows.

Inner diameter (86φn+/m) X stroke (102m/m)
X 4-cylinder displacement 2369cc 74PS Diesel engine Fuel used: JI No. 52 diesel oil Lubricating oil =
CC class #30 operating conditions: 3800rpIlx full load
100 hours Water temperature: 110°C Oil temperature: 100°C Results of bench durability and wear comparison tests performed by assembling the treated steel cylinder liner (sliding surface A) with the piston rings of the present invention and comparative example shown in Table 1. is shown in Figure 6.

In Figure 6, the amount of wear on the cylinder liner is the average amount of wear (μm) measured in each 45° direction per 100 hours at the top dead center position of the TOP ring, and the amount of wear on the piston ring is the average outer circumferential wear of the TOP ring. The amount (μm) is shown.

Looking at the results in Figure 6, we can see that the comparative example (
Although A) shows extremely excellent performance in terms of cylinder wear, it is clearly understood that it causes abnormal wear on the mating ring and is unfavorable in terms of compatibility as a sliding surface pair structure. Comparative Examples CB) to (D) showed significant improvement in the wear of the mating ring, but an increase in cylinder wear was observed, which was not sufficient. In contrast, (E) and (F) are examples of the present invention.
), the cylinder wear is slightly worse compared to Comparative Example (A), but it is at a generally satisfactory level, and the ring wear is drastically reduced to about 174° 1/6 of Comparative Example (A). . Therefore, the present invention can be said to be an ideal sliding surface pair structure in which mutual compatibility is dramatically improved by the synergistic action of each sliding surface (A) and (B).

Example 2 94 (outer diameter) φm processed to specified dimensions and degreased and cleaned
mX90 (inner diameter) φm / m x 167 m /
The inner circumferential surface of a cast iron cylinder liner (material equivalent to 2FC30) with a length of
Honing shoe pressure using slurry containing particles 1.
0kg/cIII2, rotation speed x stroke x time: 8
At the same time, a spiral cross groove is machined on the inner circumferential sliding surface under the conditions of 0 rpm/win x 30 times/m1n x 2 minutes,
SiC particles were embedded in the groove and plateau portion, and then a honing shoe pressure of 1.0 kg/am was applied using a slurry containing SiC fine particles with an average particle size (400 mesh).
Rotation speed x stroke x time = 80rpn+ /+++i
The inner peripheral sliding surface was polished and finished under the conditions of n x 30 times/lllln x 2 minutes, and finally washed with kerosene and degreased by a conventional method.

The sliding surface (A) of the cylinder liner obtained by this processing has SiC particles uniformly embedded in the spiral cross grooves and plateau portions at an embedding area ratio of approximately 8%, and has a roughly rhombic shape surrounded by the cross grooves. The occupied area ratio of the plateau portion (plateau ratio) is approximately 89%, and the surface roughness of the plateau portion is approximately 5μ.
It was m.

On the other hand, 90φm/m (outer diameter) x 2.5 m/m (
The groove cut into the outer circumferential surface of a spheroidal graphite cast iron piston ring (TOP ring) with width) x 3.8 m/m (thickness) was coated with the same base thermal spraying as in Example 1. A mixed powder of each powder (first invention) was plasma sprayed under the same conditions to the same thickness and polished to the same surface roughness, and the sample piston ring was
Furthermore, a Cr-plated ring was used for the 2nd and oN rings.

FIG. 8 is a sectional view of a piston ring according to the present invention, where (8) is a piston ring, (9) is a groove (10) on a sliding surface.
) indicates a sprayed layer.

As a comparative example, a cast iron cylinder liner treated in the same manner as in the example and an untreated cast iron cylinder liner were used, and the piston ring had a Mo wire inserted into a groove cut on the outer circumferential surface. A Mo sprayed piston ring that was flame sprayed using a gun was used for METC03. (Surface porosity approximately 20%, hardness Hrs V 700) Table 2 shows combinations of the present invention and comparative examples.

Table 2 The test engine and test conditions were as follows.

Inner diameter (90φm/m) X stroke (86m/m) x 4
Cylinder displacement 2188cc 72PS/4200rp
m Diesel engine Fuel used: JIS No. 2 light oil Lubricating oil: #30 Operating conditions:
Driving on the road Mileage distance until measurement: 47.606 km FIG. 7 shows the results of a wear comparison test of the cylinder liner and piston ring after driving on an actual vehicle in the combinations of the present invention and the comparative example shown in Table 2.

In Fig. 7, the amount of wear on the cylinder liner is 10. The average wear amount (μm) of each 45 @ direction measurement value per OOOKm is shown, and the wear amount of the piston ring is the average outer circumferential wear amount (μm) of the TOP ring.

According to the test results in FIG. 7, the comparative example (H) is different from the comparative example (H).
Compared to G), the cylinder liner wear is reduced by about 70%, but the cylinder liner wear is dramatically increased by about 3.9 times. On the other hand, in the present invention (F), compared to comparative example CG), the cylinder wear is reduced to about 50%, and the ring wear is reduced to about 90%. In addition, the present invention (F) has the following characteristics compared to the comparative example (H):
Cylinder wear has been significantly improved by approximately 75%, and ring wear has been reduced to approximately 1/4.

Therefore, the superiority of the sliding surface pair structure of the present invention is clearly understood from the above results.

(Effects of the Invention) The present invention aims to reduce the average particle diameter of hard particles such as SiC dispersed and embedded in one sliding surface (A), increase the embedded area ratio of the hard particles, and increase the occupied area ratio of the plateau portion (plateau area ratio). The surface quality of the sliding surface (A) was improved by specifying the maximum surface roughness of the plateau portion, etc., and the other sliding surface (B) was coated with high chromium cast iron powder and Fe-C-Cr. A sprayed layer formed by plasma spraying a mixed powder obtained by mixing a mixed powder with an alloy powder and an MO powder in a specific ratio (first invention), or a self-fluxing alloy powder further mixed in a specific ratio with the mixed powder of the first invention By applying a thermal spray layer (second invention) formed by plasma spraying mixed powders, the defects of each powder can be compensated for and the sliding surface (A
), the wear on the sliding surface (B), which was a defect in the conventional method, was significantly reduced, and the wear on both surfaces was successfully balanced appropriately. Therefore, the present invention can correct the defects of the conventional sliding member embedded with SiC particles and fully exhibit its characteristics, thereby expanding the scope of its application and improving the durability of internal combustion engines, etc. This has a significant practical effect in providing a sliding surface pair structure that can further improve reliability.

In the above explanation, the combination of a cylinder liner and a piston ring of an internal combustion engine has been explained as an example, but the present invention is not limited to this example, and can be applied to any sliding device that requires wear resistance and scuffing resistance. Of course, it can also be applied to a face-to-face structure.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a cylinder liner, FIG. 2 is an enlarged sectional view of section A in FIG. 1 showing the sliding surface of the cylinder liner according to the present invention, and FIG. FIG. 3(b) is a partially enlarged sectional view schematically showing the surface condition of the sliding surface before finishing processing, and FIG. 3(b) is a partially enlarged sectional view corresponding to FIG. 3(a) after finishing processing. (c) is a partially enlarged cross-sectional view similar to Fig. 3 (b) showing the surface state in which hard particles are buried in the cylinder liner base material, Fig. 4 is an explanatory diagram of the plateau rate calculation method, and Fig. 5 is Figure 6 is an explanatory diagram showing the surface roughness of the sliding surface of the cylinder liner, and the steel cylinder liner according to the present invention and the piston rings of the present invention and comparative examples were assembled and subjected to a bench durability and wear comparison test. Figure 7 is a graph showing the results of the analysis, and shows the wear after running on an actual vehicle in the combination of the present invention and the comparative piston ring using the cast iron cylinder liner according to the present invention and the untreated cast iron cylinder liner as the cylinder liner. Graph showing comparative test results, FIG. 8 is a sectional view of a piston ring according to the present invention. 1 Nijilinda liner, 2: Sliding surface, 3: Oil sump groove, 4 Nibrad part, 5: Hard particles, 6: Cross-sectional curve, 7: Base line, 8
: Piston ring, 9: Groove on outer circumferential sliding surface, 10: Sprayed layer, depth of H2 oil reservoir groove. Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A specific pattern of oil sump grooves arranged in a base material made of steel or cast iron, and an average grain size uniformly dispersed and buried inside the grooves and plateaus at an area ratio of 3 to 12%. 5~20μ
m hard particles and a smoothed upper surface (
A), high chromium cast iron powder whose grain size is not coarser than 74 μm, and Fe-C-Cr alloy powder are mixed to form a composition containing 3.0 to 7.0% C, 25 to 55% Cr, and the balance by weight. 65 to 95% by weight of a mixed powder containing substantially Fe and further 5 to 35% by weight of Mo powder whose particle size is not coarser than 74 μm.
A sliding surface pair structure comprising a sliding surface (B) having a sprayed layer formed by plasma spraying a mixed powder mixed with the above. 2. The sliding surface pair structure according to claim 1, wherein the specific pattern of the oil sump groove portion is a continuous or discontinuous spiral or intersecting groove shape. 3. The occupied area ratio (plateau ratio) of the plateau part on the sliding surface (A) surrounded by the oil sump groove part is plateau ratio 1
．． The sliding surface pair structure according to claim 1, wherein the sliding surface pair structure is 75 to 95% at a depth of 2 μm from the 0% base line. 4. Hard particles are SiC, Al_2O_3, Cr_2O_
3. The sliding surface pair structure according to claim 1, which is a single particle selected from the group consisting of Si_3N_4. 5. The maximum surface roughness of the plateau part of the sliding surface (A) is 3~
The sliding surface pair structure according to claim 1, wherein the surface roughness of the sliding surface (B) is 3.0 μm or less. 6. A specific pattern of oil reservoir grooves arranged in a base material made of steel or cast iron and an average grain size of 5 to 20μ uniformly dispersed and buried inside the grooves and plateaus with an area ratio of 3 to 12%.
A composition is prepared by mixing a sliding surface (A) having hard particles of m and a smoothed upper surface, high chromium cast iron powder with a grain size not coarser than 74 μm, and Fe-C-Cr alloy powder. 65 to 85% by weight of a mixed powder containing 3.0 to 7.0% of C and 25 to 55% of Cr with the balance being substantially Fe, 5 to 25% by weight of Mo powder with a particle size not coarser than 74 μm, and Self-fluxing alloy powder 5 to 25 whose particle size is not coarser than 74 μm
A sliding surface pair structure comprising a sliding surface (B) having a sprayed layer formed by plasma spraying a mixed powder mixed with % by weight. 7. The sliding surface pair structure according to claim 6, wherein the specific pattern of the oil sump groove portion is a continuous or discontinuous spiral cross groove shape. 8. The occupied area ratio (plateau ratio) of the plateau part on the sliding surface (A) surrounded by the oil sump groove part is plateau ratio 1
．． The sliding surface pair structure according to claim 6, wherein the sliding surface pair structure is 75 to 95% at a depth of 2 μm from the 0% base line. 9. Hard particles are SiC, Al_2O_3, Cr_2O_
3. The sliding surface pair structure according to claim 6, which is a single particle selected from the group consisting of Si_3N_4. 10. The maximum surface roughness of the plateau part of the sliding surface (A) is 3
The sliding surface pair structure according to claim 6, wherein the sliding surface (B) has a surface roughness of 3.0 μm or less. 11. The sliding surface pair structure according to claim 6, wherein the self-fluxing alloy powder is made of a Ni-Cr alloy.