JPH0198764A - Combination of cylinder and piston ring - Google Patents

Abstract

PURPOSE:To improve mutual compatibility by combining a cylinder where hard particles are dispersed and buried in an oil sump groove portion of a sliding surface with a piston ring where mixed powder of high-carbon low-silicon ferroalloy powder and No powder is plasma-sprayed. CONSTITUTION:A cylinder liner 1 is composed of 0.35-0.55wt.% C, 0.40wt.% or less Si, 0.40-1.00wt.% Mn, and residue Fe. Hard particles (SiC, Al2, O3 etc.) having an average particle size of 3-20mum are uniformly distributed and buried in the interior portion of an oil sump groove portion 3 of a specified pattern formed on a sliding surface 2 and a plateau portion 4 at area rate of 5-15%, and the top surface thereof is polished to be smooth. On the other hand, a piston ring 8 is composed of 8.5-9.5% C, 65-70% Cr, 1% or less Si and residue Fe. Mixed powder of 75-85% high-carbon low-silicon ferroalloy having a particle size of 74mum or less and 15-30% Mo powder having a particle size of 74mum or less is plasma-sprayed to the outer peripheral sliding surface groove 9 to provide a flame coating layer 10. Thus, there is good compatibility between two members to reduce abrasion.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a combination of a cylinder (including a cylinder sleeve, a cylinder liner, a cylinder block, etc.; the same shall apply hereinafter) and a piston ring used in internal combustion engines, etc. .

More specifically, the present invention is based on the applicant's earlier application Teal Patent J! No. 59-274551 (Jikai 61-1
57875) regarding the improvement of the "combination of cylinder and seal ring".

[Conventional technology] Internal combustion engines have become more efficient in recent years, and at the same time, the load on functional parts such as piston rings and cylinders has increased and the required quality has become more advanced in order to prevent pollution and save energy. It has become. In other words, these functional parts must have wear resistance, oil retention, and scuffing resistance that can withstand a reduction in lubricant consumption (LOG) under conditions of high temperature and high load, as well as weight reduction and reduction of friction loss. There is a strong desire for this, and in other words, a more desirable combination of a cylinder and a piston ring, or a combination of a cylinder and a piston ring that is compatible with each other is 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, spiral grooves are formed on the sliding surface of the cylinder using a lapping tool using a slurry or paste containing SiC, and SiC particles are embedded. A wear-resistant treatment consisting of a process of scraping off peaks, removing sharp corners of particles, and pushing in protruding particles, and if necessary, lapping with a slurry or paste containing more particles than in the previous process. will be held. This treatment method has been put to practical use in some cylinder liners made of cast iron or steel, and it exhibits excellent performance in terms of the wear resistance of the cylinder itself, and is also significantly lower in cost than special wear-resistant cast iron or chrome-plated cylinders. When applied to a thin-walled steel cylinder, it enables weight reduction and bore amplification within the range of use of ready-made engine blocks, and is therefore receiving high praise.

However, although cylinders that have undergone this treatment exhibit outstanding performance in terms of their own wear resistance, they also have the drawback of causing significant wear to the mating piston ring, making them difficult to use in modern high-performance engines. Under the harsh operating conditions of

Therefore, the prior invention has provided a sliding surface pair structure that satisfies the above-mentioned requirements, eliminates the conventional problems, and fully utilizes the advantages of the cylinder sliding surface in which the SiC particles are embedded. An improved cylinder made of steel or cast iron in which medium and fine SiC particles are dispersed and buried in a specific pattern of oil reservoir grooves and on the surface of a plateau surrounded by the grooves at a specific area ratio, and Fe- This is an attempt to provide a combination with a seal ring that is plasma sprayed with a mixed powder of C-Cr alloy powder and Mo powder mixed in a specific ratio.

Specifically, a specific pattern of oil reservoir grooves is provided on the sliding surface of a cylinder made of steel or cast iron, and an area ratio of 3 to 12% is provided inside the grooves and in the plateau portion with an average particle size of 5 to 2.
A cylinder with a sliding surface in which hard particles of 0 μm are uniformly dispersed and embedded and whose upper surface is smoothed, and a cylinder containing 03.0 to 9.0% Cr and 55 to 70% Cr by weight, with the remainder being substantially F whose grain size is not coarser than 74μm
e-C-Cr alloy powder 65-85% by weight and particle size 74μ
In a previous application, we proposed a combination of a cylinder and a seal ring with a seal ring formed on the sliding surface with a sprayed layer formed by plasma spraying a mixed powder of 15 to 35% by weight of Mo powder that is not coarser than m. did.

[Problem that the invention seeks to solve]

In the prior invention, the cylinder was constructed in such a way that it could fully demonstrate its characteristics without impairing the wear resistance of the cylinder itself, so the wear of the cylinder liner was small, but the wear of the piston ring was less than that of the chromad liner that had been put into practical use. (
Comparing the hard chrome plated surface with the level of the polished liner, the level is still unsatisfactory, and further improvement is desired.

[Means for solving problems]

The present invention has a weight ratio of C0.35 to 0.55%, Si0.
40% or less, Mn 0.40 to 1.00%, and the remainder substantially Fe.A specific pattern of oil reservoir grooves is provided on the sliding surface of the cylinder, and inside the grooves and plateau portions. A cylinder having a sliding surface in which hard particles with an average particle size of 3 to 20 μm are uniformly dispersed and embedded in an area ratio of 5 to 15% and a smooth upper surface, and
8.5 to 9.5%, Cr65 to 70%, Si 1.0% or less, and the balance is substantially Fe.The particle size is 74μ.
High carbon low silicon Fe-C-Si-C not coarser than m
A cylinder and a piston ring having a sprayed layer formed on the sliding surface by plasma spraying a mixed powder of 70-85% by weight of r-alloy powder and 15-30% by weight of Mo powder with a grain size not coarser than 74 μm. provide a combination of

The most important feature of the configuration of the present invention is that the composition of the cylinder is changed to C0
, 35-0.55%, SLo, 40% or less, MnO,
The steel contained 40 to 1.00% of Mo.
The composition of the chromium alloy powder that is sprayed onto the piston ring base material together with the powder is C8.5-9.5%, Cr 65-70.
%, S'i 1% or less, balance FeO high carbon low silicon Fe
-C-Si-Cr, and as a result, it was possible to obtain performance that greatly exceeds the cylinder wear and ring wear of the cylinder and piston ring combination according to the prior invention.

The specific configuration of the present invention will be described below. FIG. 1 is a longitudinal cross-sectional view of the cylinder liner, in which (1) is the cylinder liner, (2) is the sliding surface that is the inner peripheral surface of the cylinder liner,
FIG. 2 is an enlarged sectional view of section A in FIG. 1 showing the sliding surface of the cylinder liner (1) to which the present invention is applied, and (3) is an enlarged cross-sectional view of the sliding surface of the cylinder liner (1) to which the present invention is applied, and (3) is an enlarged sectional view of the sliding surface of the cylinder liner (1) to which the present invention is applied, and (3) is an enlarged sectional view of part A of FIG. (4) is a smooth sliding surface surrounded by the core oil reservoir groove (3) (hereinafter referred to as the plateau portion); (5) is Hard particles buried inside the core oil reservoir groove and in the plateau. FIG. 3(a) shows the cylinder liner sliding surface immediately after the hard particles (5) are buried inside the core oil reservoir groove and in the plateau. (A) is a partially enlarged sectional view schematically showing the surface condition, FIG. 3(b) is a partially enlarged sectional view corresponding to FIG. 3(a) after finishing processing, and FIG. 4 is a stylus. A cross-sectional curve obtained by moving the cylinder liner in the axial direction of the inner circumferential surface or a roughness curve (6”) with a cutoff value of 2.5n+/m or more (JIS-80601-1970
) is a drawing explaining a part of the cross-sectional curve (6).
There is an arbitrary straight line, that is, a base line (7), which is parallel to the average line of the curve (6). ．． , lz.

ls, 1a-1, and T, the corresponding song vA (6) <7) Plateau rate at baseline (7) (occupancy ratio of plateau part)
is determined by the following formula.

X 100 (%) Therefore, in order to obtain the cylinder liner according to the present invention, S
It is obtained by rotating and reciprocating the inner peripheral surface of the cylinder liner (1) using a roughing tool or honing shoe using a polishing liquid mixed with a slurry or paste containing hard particles such as iC. That is, by this machining, the hard particles (5) carve the oil sump grooves (3) so as to form a pattern specified by the movement of the tool, for example, a diamond-shaped pattern along intersecting spiral trajectories, and at the same time carve the core oil sump grooves ( 3) and the plateau part (4), and at the same time, a roughly rhombic plateau part (4) surrounded by the kernel oil reservoir groove part (4) is formed (Figures 2 to 3 (a)
(see (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 using a two-step operation as described above,
In the second step, the protrusions on the inner circumferential surface of the cylinder liner between the grooves are scraped off, sharp edges of the hard particles are removed, and the protruding hard particles are further pushed into the grooves and into the plateau portions. In any of the above methods, in order to obtain a cylinder liner (FIG. 3(b)) in which the upper surface of the sliding surface (2) composed of the plateau portion (4) and the hard fine particles (5) is smoothed. After the above step, the inner circumferential surface of the cylinder liner is rough-finished or honed using a polishing liquid mixed with a slurry containing fine-grained hard particles, or polished with a honing shoe equipped with a fine-grained grindstone. The unevenness of the previous process is removed.

It is then washed and degreased. Here, the core oil sump groove (3)
The depth, width, embedded area ratio of the hard particles (5), occupied area ratio of the plateau part (4), etc. are determined by factors such as the base material material, the size of the hard particles, tool pressure, rotation speed, machining speed and time. ruled by. The selection of these factors will be described later.

In the cylinder which is one of the combinations according to the present invention, the hard particles are SiC, A1gOt+CrzOi+5i
A single particle selected from the group consisting of J4 can be used, but the property of embedding the hard particle so that it is firmly held in the base material, that is, the embeddability, the hard particle is not crushed during processing. It is desirable to use SiC particles from the viewpoint of properties such as 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. Although this is related, it is necessary to limit the average particle size after being embedded to 3 to 20 μm so as not to impair the wear resistance and scuffing resistance of the cylinder (in addition, in order to reduce the wear of the mating piston ring) That is,
If the average particle size is less than 3 μm, the cylinder itself will lack wear resistance, and if hard particles larger than 20 μm are embedded, it will lack dispersibility (density), and as the relatively soft base material gradually wears out, the hard particles will deteriorate. The local surface pressure is high (there is a risk of inducing scuffing and accelerating wear of the mating piston ring. The more preferable range is 7 to 15 μm. Therefore, the hard particles have a high embedded area ratio (5 to 15%). It is important that the particles be embedded finely and uniformly into the cylinder sliding surface with an appropriate particle size.

The reason for limiting the embedded area ratio of hard it'R1 particles on the cylinder sliding surface is that if it is less than 5%, the wear resistance of the cylinder itself
The scuffing resistance is insufficient, and if it exceeds 15%, the wear of the mating piston ring increases and balanced wear cannot be achieved as a sliding surface pair structure, so the range is set to 5 to 15%. A more preferable range is 5 to 10%. The occupied area ratio of the plateau portion surrounded by the spiral cross grooves (plateau ratio) is preferably 75 to 95% at a depth of 2 μm (h) from the base line (8) with a plateau ratio of 1.0%. The reason for this limitation is that if the plateau rate is less than 75%, the number of oil sump grooves will inevitably increase, causing an increase in O and C, which is undesirable.On the other hand, if the plateau rate exceeds 95%, the number of oil sump grooves will decrease. This is because the tendency for scuffing increases. A more preferable range is 80 to 90%. In addition, the plateau rate is changed from the baseline (8) with a plateau rate of 1°0% to 2
The reason for choosing μm is that the amount of oil retained on the cylinder sliding surface at the initial stage of engine break-in is optimized, O, C, and so on can be suppressed to the necessary minimum, and the plateau rate is 75 to 95% (pressure receiving area 75 to 95%). %) is approximately 2 μm or less, and the time required for initial break-in operation can also be shortened (see FIG. 5). The maximum surface roughness H 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 3μm, the surface may lack oil retention and initial scuffing may occur;
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 μmT.

In order to obtain a cylinder that satisfies the above requirements, usually
In the first step (grooving and embedding of SiC fine particles), the cylinder sliding surface is honed using a slurry containing SiC fine particles with an average particle size of 120 to 280 mesh at a shoe pressure of 0.5 to 2.0 kg/cd and a rotation speed. X stroke x
Time: 50-250rpIll/lll1n x 20-6
Under the conditions of 0 times/n+in x 1 to 3 minutes, the second step (
S with an average particle size of 280 to 800 mesh in finishing)
Using slurry containing iC fine particles, honing shoe pressure 0, 5-2.0 kg/aJ, rotation speed x stroke x time = 50-25 Orpm/a+in x 20-60 times/
The cylinder sliding surface may be finish honed for 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, 5.
In some cases, the iC1i particles exhibit a surface state in which they are buried in the cylinder matrix.

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. However, in the surface state shown in FIG. 3(b), the total embedded area ratio of SiC fine particles is 5 to 1.
Compared to 5%, 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 piston ring of the combination according to the present invention will be described.

The piston ring features high carbon, low silicon Fe-C-S
The significance lies in the use of a plasma sprayed ring made of a mixed powder of i-Cr alloy and Mo.
Cr alloy powder has a lower St content than conventional FCrH3 (high carbon ferrochrome), so there is no α-iron precipitation and most of it is (CrFe). It is a C3 powder with improved wear resistance.

In addition, the material of the base material is C0.35~0.55%, SiO,
40% or less, Mn 0.40 to 1.00%, and the remainder substantially Fe. Carbon and manganese are both matrix reinforcing elements, and their content is 0.
．． When it is less than 35% and 0.40%, the retention ability of hard particles decreases. If the carbon content is less than 0.35%, there will be less pearlite precipitation and more primary ferrite will be present, and if the manganese content is less than 0.40%, there will be less solid solution manganese in the ferrite and more pro-eutectoid ferrite, both of which will reduce the strength. bring about. On the other hand, if the carbon content exceeds 0.55%, pearlite precipitates excessively, making it difficult to embed hard particles such as S'rC, making it easier for SiC particles to fall off as hard particles such as SiC become finer, and causing thin walls. This leads to deterioration of plastic workability when the liner is flanged. .

In addition, if the manganese content exceeds 1.00%, the hardness force (
It becomes higher than necessary, leading to deterioration of plastic workability. Therefore, the carbon content is 0.35 to 0.55%, and the manganese content is 0.40 to 1.00%, but more preferably carbon content is 10.40 to 0.50%, manganese content is 4 to 4.
~0.8%. Silicon is necessary as a deoxidizing element and is also necessary as a ferrite forming element that has a strong influence on the embeddability of hard particles. If the content exceeds 0.40%, the amount of ferrite becomes too excessive and hard particles tend to fall off.

The tempering condition of the base material is as hot rolled, annealing, normalizing, quenching and tempering, etc., but it is normalized and tempered at a point where a structure with a balance of pro-eutectoid ferrite and pearlite is obtained. Annealing, especially normalizing, is preferred. Normalizing is 8
00-b After soaking, it is preferably air-cooled to obtain a pearlite volume fraction of 40 to 60% and a pro-eutectoid ferrite structure in the remainder.

Next, the other piston ring of the combination according to the present invention will be described.

The feature of the piston ring is that a mixed powder of Fe-C-Si-Cr alloy powder and Mo powder is plasma sprayed.The significance of this is that the Fe-C-Si-Cr alloy powder and Mo powder are mutually Through complementary action,
The aim is to dramatically improve the compatibility of the piston ring with the cylinder, appropriately balance the wear of both rings, and improve scuffing resistance, thereby further enhancing the durability and reliability of internal combustion engines.

Next, the reason for limiting the composition of the Fe-C-Si-Cr alloy powder and Mo powder will be described.

C refers to Cr in the form of carbide (CrFe)
? It is an essential element for fixation as C3, and if C is less than 8.5% by weight, it becomes (CrFe)? If the absolute amount of C3 is insufficient, the wear resistance and scuffing resistance of the piston ring will be unsatisfactory, and if it exceeds 9.5% by weight, the adhesion to the base material to be thermally sprayed will be impaired. Free carbon (graphite) is Fe −
9 as it may occur in the C-Si-Cr alloy.
．． It is desirable to keep it below 5%.

Cr is the main component of the Fe-C-Si-Cr alloy, and is an element that has a strong carbide-forming effect, and most of the C contained in the alloy is converted into (CrFe). It is fixed as a carbide such as CI. Therefore, these carbides are Fe
-C-Si - It is a main component of the -Cr alloy, and although there is a slight change in composition, it is also included as an intervening phase in the sliding surface of the mixed thermally sprayed piston ring, and has excellent wear resistance against hard particles of the cylinder. It has an important effect of imparting scuffing resistance. In the above composition, Fe-
Some amount of C, which may be present in the C-Si-Cr alloy, is burned off during spraying and is therefore not incorporated into the sprayed layer. If the Cr content in this Fe C-Si-Cr alloy powder is less than 65% by weight, the hardness and heat resistance of the carbide in the piston ring sliding surface will be insufficient, resulting in poor wear resistance and scuffing resistance of the piston ring itself. When the amount of Cr decreases and exceeds 70% by weight, Cr, which is not fixed as carbide, tends to deteriorate the wear resistance of the piston ring, while at the same time tends to accelerate the wear of the mating cylinder. Therefore, the Cr content is 6
The content should be in the range of 5 to 70% by weight.

High carbon low silicon Fe-C-Si-C used in the present invention
The r-alloy powder is manufactured by a stamping method. Alternatively, it is manufactured by Awamura Metal Industry Co., Ltd. under the trade name QC-Chrome as a special ferrochrome that is not JIS standard ferrochrome.

High carbon ferrochrome specified by JIS (e.g. FCrH
3: St 2.0% or less, C: 8.0% or less) is composed of α-iron, (CrFe), and CS, but when the Si content is high, a large amount of α-iron containing Si as a solid solution is precipitated. . However, in the case of the present application, since Si was kept at a low level of 1.0% or less, there was no precipitation of α iron, and most of it was (CrFe). It becomes C3.

Next, the reason why the grain size of the FeC-Cr alloy powder is limited to 74 μm or less will be described.

-a, the sprayed layer has pores, which become oil pockets and contribute to scuffing resistance, but when the pores become coarse, the self-bonding force between the sprayed particles is insufficient and the sprayed particles fall off during sliding. This causes the seal ring and mating cylinder to wear out. 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 the particle size of the thermal spraying material, especially the thermal spray powder, is greatly affected, the particle size is 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.

In the seal ring of the present invention, Mo is further mixed and sprayed. 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, since Mo powder is sprayed as a mixed powder with Fe-C-Si-Cr alloy powder by plasma spraying, each sprayed particle coexists in a molten state and the Mo particles themselves have low oxidation resistance. eased.

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, M
Even ultrafine powder, which cannot be used due to its sublimation property, can be used by granulating it to achieve good uniform distribution. Mo
The reason why the particle size of the powder is set to be 74 μm or less is because if the particles are coarser than 74 μm, the surface porosity of the thermally sprayed layer increases, resulting in poor geographical distribution and deterioration of abrasive wear resistance.

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

If the apparent density of the Mo granulated powder is 2.5 g/cJ or less, preferably 2.0 to 2.5 g/cJ or less, it will be mixed with the Fe-C-Si-Cr alloy powder in the thermal spraying stage.

The uniform distribution with the powder is improved, and even if fine granulated powder is used, it is possible to eliminate thermal spraying operation troubles due to poor fluidity during thermal spraying. Next, the reason for limiting the amount of Mo powder mixed is that if the amount is less than 15%, Mo's unique scuffing resistance and resistance to abrasive wear between sliding surfaces due to improved bonding strength between each sprayed particle, etc. If the amount exceeds 30%, the oxidation resistance of the sprayed layer deteriorates, resulting in a rapid decrease in interparticle bonding force during internal combustion engine operation, and promoting abrasive wear.

Therefore, the amount of Mo powder mixed is 15-30% by weight,
Preferably it is in the range of 15 to 25% by weight. On the other hand, Fe
The amount of the -C-Cr alloy powder mixed is 70-85% by weight, or 75-85% by weight, depending on the amount of Mo powder mixed.

Even when the seal ring is sprayed directly onto cast iron or steel as the base material, it can obtain a considerable adhesion strength, but when used under more severe conditions, Ni-Mo can be sprayed as a base material.
A base alloy (70% Mo) or the like may also be used.

Hereinafter, this will be explained in detail with reference to examples.

〔Example〕

The following table shows combinations of cylinder liners and piston rings as examples of the present invention and comparative examples.

The hard chrome liner (chromad liner) of Comparative Example 1 is made as follows.

After 30 to 60 minutes at 800 to 850°C as pre-processing heat treatment, the inner diameter of the STKM15A tube material, which had been air-cooled and normalized, was bored to give it a semi-finished finish, and further press work was performed to flange the cylinder liner. The prepared tube material was roughly lapped with a 200' coarse grindstone, and then finished lapped with a 600'' finishing whetstone to obtain a 107φ (outside diameter) x 105φ (
A thin liner with inner diameter') X203 (length)+Il/Il+ was prepared. The wrapping conditions are 70-1
100rp (rotation speed) x 20 times/min (stroke) x
Conditions of 1 to 3 minutes (hours) were used.

The method for producing the liner in Comparative Example 2 and Examples is as follows.

107φ processed to specified dimensions and degreased and cleaned (outer diameter)
m/m x 105φ (inner diameter) +/m x 203m/
The inner circumferential surface of a steel cylinder liner (material: as listed in Table 1) with a length of
kg/j, rotation speed x stroke x time: 80 rpm
/■ Under the conditions of 1n x 30 times/11lin x 2 minutes, a spiral cross groove was formed on the inner peripheral sliding surface, and at the same time SiC particles were embedded in the groove and the plateau portion, and then SiC fine particles with an average particle size of 400 mesh were formed. Using a slurry containing
Honing shoe pressure 1.0ksr/aJ, number of rotations x
Stroke x time: 80 rpm/a+in x 3
The inner peripheral sliding surface was polished and finished under the conditions of 0 times/lll1n x 2 minutes, and finally washed with kerosene and degreased by a conventional method.

The sliding surface of the cylinder liner obtained by this process is S
The iC particles are uniformly embedded in the spiral cross grooves and the plateau part at an embedded area ratio of about 6%, and the occupied area ratio of the approximately rhombic plateau part surrounded by the cross grooves (the plateau ratio is about 80%, the plateau part is approximately 80%). , the maximum surface roughness of the area is approximately 3 μm,
On the other hand, the piston ring center of the present invention is 105φflI/ll+(outer diameter) x2.5 m/
a+ (width) Fe having the composition and particle size shown below
A mixed powder of -C-Si-Cr alloy powder and Mo powder was plasma sprayed using a METCO7MB gun, and the thickness of the mixed sprayed layer was 180 μm, the grooves were completely filled, and the surface roughness was reduced. A sample piston ring was prepared by polishing to a thickness of 0.5 to 1.5 μm. Also, 2n
The d ring is a cast iron ring with a chrome plated outer circumference, and the o
A steel ring with a coil expander with chrome plating on the inner and outer peripheries was used for the N ring.

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

-FCrH 363 μm or less 64.2% Cr, 6.56% C, 1.6% St/High chromium cast iron 63 μm or less 2011 m or more 34.8% Cr
, 5.74%C ・Fe-C-5i-Cr 63μm or less 66.3%
Cr, 9.1%C, 0.2%St/Mo powder (3-5t
tm Mo jj11 powder granulated with an organic binder) 99% or more Mo 74 #m or less ・Hard chrome plating of comparative example: Plating thickness 0.3 m/m
Hardness Hv960 Table 2 shows the mixing ratio of each thermal spray powder of the seal ring according to the present invention and the seal ring as a comparative example, Fe-C-C
The C and Cr contents of the mixed powder with the r alloy powder, the surface porosity of each sprayed layer, and the surface roughness and surface hardness of the finished surface are shown.

Table 2 The treated steel cylinder liner and the piston rings of the present invention and comparative example shown in Table 1 were assembled, and a bench durability and wear comparison test was conducted. The results are shown in FIG.

FIG. 7 is a side view of the piston ring according to the present invention, in which (8) is the piston ring and (9) is the groove (10) on the sliding surface.
) indicates a sprayed layer.

The test specimen, engine, and test conditions were as follows.

Inner diameter (105φ-7m) X process (125m/@)
6-cylinder total displacement 6.494CC175PS diesel engine Operating conditions 3100rpm x full load x 100”
Water temperature: 110°C (engine outlet) High water temperature test In Figure 6, the wear amount of the cylinder liner is the average wear M (μm) of the measured values in each 45° direction per 100 hours at the top dead center position of the TOP ring, and The wear amount indicates the average outer peripheral wear amount (μm) of the TOP ring. Further, the total amount of wear on the liner and ring is a relative value with the total amount of wear (μm/100Hr) of Comparative Example 1 taken as 100%.

Looking at the results in Figure 6, Comparative Example 1, which is a combination of the currently used chromade liner and phosphate-treated piston ring, shows extremely excellent performance in terms of liner wear, but causes abnormal wear on the mating ring, resulting in poor compatibility. It is clearly understood that this is unfavorable.

Comparative Example 2 has inferior performance to Comparative Example 1 in both liner wear and cylinder wear.

In contrast, the embodiments of the present invention provide the best results in terms of both liner wear and cylinder wear.

The cylinder and piston according to the present invention have been dramatically improved, and have a performance equivalent to or better than that of the Chromard liner, and also do not cause waste liquid pollution caused by wet plating method 1, unlike the Chromard liner. The combination with the ring can be said to be ideal.

[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 based on FIG. 3(b) showing the surface condition where 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 An explanatory diagram showing the surface roughness of the sliding surface of the cylinder liner, Figure 6 shows the steel cylinder liner according to the present invention and the piston rings of the present invention and comparative examples assembled and subjected to a bench durability and wear comparison test. The graph showing the results, FIG. 7, is a cross-sectional view of the 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 peripheral sliding surface, 10: Sprayed layer, H: Depth of oil sump groove.

Claims (1)

[Claims] 1. C0.35 to 0.55%, Si 0.40% by weight
Hereinafter, a specific pattern of oil sump grooves is provided on the sliding surface of a cylinder having a composition consisting of 0.40 to 1.00% Mn and the remainder substantially Fe, and an average particle size is provided inside the grooves and in the plateau portion. Hard particles of 3 to 20 μm have an area ratio of 5 to 20 μm.
A cylinder with a sliding surface that is 15% uniformly dispersed and buried and whose upper surface is smoothed, and a weight ratio of C8.5~
High-carbon, low-silicon Fe-C-Si-Cr alloy powder 7 containing 9.5% Cr, 65-70% Cr, 1.0% or less Si, and the balance being substantially Fe and having a particle size not coarser than 74 μm.
0 to 85% by weight and Mo with a particle size not coarser than 74 μm
A combination of a cylinder and a piston ring, each consisting of a piston ring whose sliding surface is coated with a sprayed layer formed by plasma spraying a 15 to 30% by weight mixed powder. 2. The combination of a cylinder and a piston ring according to claim 1, wherein the specific pattern of the oil reservoir grooves is a continuous or discontinuous spiral cross groove shape. 3. The occupied area ratio (plateau ratio) of the plateau portion on the cylinder sliding surface surrounded by the oil sump groove is plateau ratio 1
．． The combination of a cylinder and a piston ring according to claim 1, which is 75 to 95% at a depth of 2 μm from a base line of 0%. 4. Hard particles are SiC, Al_2O_3, Cr_2O_
3. The combination of a cylinder and a piston ring 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 portion of the cylinder sliding surface is 3.
~7μm, surface roughness of piston ring sliding surface is 1.0
The combination of a cylinder and a piston ring according to claim 1, wherein the depth of the pores is 2 to 5 μm. 6. The sprayed layer of the piston ring is high carbon low silicon Fe-C-
Si-Cr alloy powder 75-85%, Mo powder 15-25%
A combination of a cylinder and a piston ring according to claim 1, which is obtained by plasma spraying a mixed powder of % by weight. 7. The combination of a cylinder and a piston ring according to claim 1, wherein the Mo powder is a granulated powder obtained by granulating Mo fine powder of 10 μm or less with a binder so that the particle size is not coarser than 74 μm.