JPH0351577A - Oil splashing ring - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and seizureproofness and prevent the increase of the oil consumption by forming a plated layer containing a structure in which hard ceramics particles are dispersed into a metal substrate, onto the back surface of a slidable part on which the outer peripheral surface of the slidable part and an elastic means contact. CONSTITUTION:Each Ni alloy composite dispersion plated layer 5A or iron alloy composite dispersion plated layer 5D is formed on the edge surface of the parallel parts 2a and 2a and the back surface of the part 2b of a slidable member 2 having an M-figure-shaped section of an oil splashing ring 1, and the plated layers 5A and 5A slide for a cylinder liner 1b. A coil expander is attached onto the back surface of the part 2b. The Ni alloy composite dispersion plated layer has a structure in which silicon nitride particles having a particle diameter of 3mum are dispersed in about 10vol.% into a Ni alloy substrate containing about 20wt% Ni and about 5wt.% phosphorus. The iron alloy composite dispersion plated layer has a structure in which silicon nitride particles having a particle diameter of about 3mum are dispersed in about 5vol% into an iron alloy substrate containing about 2wt% phosphorus.

Description

[Detailed description of the invention] a. INDUSTRIAL APPLICATION FIELD The present invention relates to an oil scraper ring, and more particularly to an oil scraper ring suitable for use in a reciprocating internal combustion engine.

6. Conventional technology In a reciprocating internal combustion engine, a piston reciprocates within a cylinder (
The piston ring fits into the ring groove of the piston, and its outer circumferential surface slides against the inner circumferential surface of the cylinder.

In recent years, as internal combustion engines have become lighter, faster, and have higher output, there has been an increasing demand for improving the performance quality of oil scraping rings, particularly for improving oil scraping performance and reducing consumption of lubricating oil. As for the oil scraping ring, in order to improve its peeling performance, the sliding contact area with the inner peripheral surface of the cylinder is reduced to increase the surface pressure, but due to the high performance and quality requirements mentioned above, The oil scraper ring consists of a sliding part that slides against the inner circumferential surface of the cylinder, and an expander that pushes this sliding part from the back and presses it against the inner surface of the cylinder with high surface pressure. By the way, from the above-mentioned trends in internal combustion engines,
Not only is the outer circumferential surface of the sliding part of the oil scraper ring (the sliding surface with the inner surface of the cylinder) prone to wear and seizure, but the back surface is also worn due to the strong pressing force of the expander, and this wear causes the high surface Problems have arisen in that pressure cannot be maintained and oil consumption increases. Therefore, oil scraping rings in which both the outer circumferential surface and the back surface of the sliding part are hard chromium plated or nitrided are being used. However, the hard chrome plating layer is prone to seizure and does not have sufficient wear resistance under severe sliding conditions. Although the nitrided layer has excellent wear resistance, the seizure resistance is not necessarily satisfactory under severe sliding conditions, the initial conformability is not good, and oil consumption is large at the beginning of operation.

C. An object of the present invention is to provide an oil scraper ring that has excellent wear resistance and seizure resistance even under severe sliding conditions and does not increase oil consumption.

two. Structure of the Invention The present invention provides an oil scraper ring comprising a sliding part that slides against the inner circumferential surface of a cylinder and an elastic means that presses the sliding part from behind. The oil scraper ring is characterized in that a plating layer having a structure in which hard ceramic particles are dispersed in a metal base is formed on the back surface of the sliding portion that the elastic means comes into contact with.

Ho. Example Examples of the present invention will be described below.

First, a plating layer suitable for the present invention will be explained. The following two types of plating layers are particularly suitable. One of them is 10-50% by weight cobalt, 2-10% by weight
In the base of nickel alloy containing phosphorus, metal carbide,
This is a plating layer (so-called composite dispersion plating layer) having a structure in which 5 to 30 volume % of hard ceramic particles made of nitride and/or oxide and having a particle size of 5 μm or less are dispersed. The other one is a composite dispersion plating layer that is based on an iron alloy containing 2 to 10% by weight of phosphorus and is otherwise similar to the above-mentioned plating layer. The plating layer, whose main component is nickel or iron, has relatively little change in thickness depending on the distance from the cathode (so-called good plating coverage), and the plating layer does not change easily through spaces such as windows of sliding parts. As a result of the current flowing, a plating layer is formed on the back surface of the sliding portion at the same time as plating the outer circumferential surface of the sliding portion. Therefore, 1
Since plating layers can be formed on both sides in one plating process, this is very convenient from the viewpoint of productivity. On the other hand, with chrome plating, the inner and outer peripheral surfaces cannot be plated at the same time, and the plating operation must be performed twice to form a plating layer on both the inner and outer peripheral surfaces.

Next, the rules for assembling the above-mentioned plating layer will be explained.

Cobalt dissolves in nickel to increase the hardness of the base, improve wear resistance and seizure resistance, and improve the crushing strength and fatigue strength of the surface layer. The above effect becomes remarkable when the cobalt content in the base is 10% by weight or more. Furthermore, if the cobalt content exceeds 50% by weight, the cost will increase and the nickel content will be relatively low, resulting in a small yield of Ni3P, which will be described later, and the mechanical strength of the surface layer will not be sufficient. As a result, the effects of improving wear resistance and seizure resistance become insufficient. Therefore, the cobalt content in the base is preferably 10 to 50% by weight or less.

Phosphorus increases the hardness of the base through heat treatment and contributes to improving wear resistance and seizure resistance. That is, nickel or iron reacts with phosphorus to form a Ni3P or Fe3P phase in the base, increasing the hardness of the base by a mechanism similar to the mechanical strength improvement due to the precipitated phase in age hardening. This contributes to improving wear resistance. Thus, the hardness of the base is 650-800 1-1. , the wear resistance and seizure resistance are further improved.

The heat treatment may be performed by heating to 400'C.

If the phosphorus content in the base is less than 2% by weight, the above effect will not be noticeable, and if it exceeds 10% by weight, the base will become brittle and the impact strength of the plating layer and adhesion to the base material will deteriorate. As a result, wear resistance and seizure resistance also deteriorate.

The hard ceramic particles are dispersed in the matrix to form hard spots, contributing to wear resistance and seizure resistance. However, unlike silicon carbide, it does not have a sharp end surface and has little effect of abrading the inner circumferential surface of the mating cylinder. Its particle size is 10μ
When the particle size exceeds m, the particles act as an abrasive material, and the wear of the oil scraper ring and cylinder is accelerated. Furthermore, if the amount of particles dispersed is less than 5% by volume, the effect of improving wear resistance and seizure resistance will not be significant, and if it exceeds 30% by volume, the mechanical strength of the plating layer will decrease and the wear resistance will deteriorate. At the same time, the mating cylinder begins to wear out. Therefore, it is preferable to disperse 5 to 30% by volume of hard ceramic particles having a particle size of 5 μm or less, particularly preferably 0.3 to 5 μm, in the matrix. Examples of hard ceramic particles include silicon nitride (Si:
+N4), chromium oxide (Crz(L+), chromium carbide (
Particles such as Cr, C2) are suitable. When silicon nitride particles are dispersed in the nickel alloy base of the plating layer, Ni and I are added to the particle surface by heat treatment at 400°C.
Sj grows and exhibits an adhesion effect between the base and particles, further improving the mechanical strength of the plating layer. If the heating temperature is too high, the adhesive effect described above will be reduced. For example, when heated to 600"C for 4 minutes, almost all of the silicon nitride particles become Ni3Si. Also, the wear resistance due to the silicon nitride particles,
The effect of improving seizure resistance is also lost.

As the material for the sliding part, relatively high carbon steel that exhibits sufficient rigidity is suitable. When providing a nitrided layer as the base of the plating layer described above, use a material containing chromium, which has a strong affinity for nitrogen, such as martensitic stainless steel SUS4.
40B etc. are suitable.

As the material for the expander, relatively high carbon steel is preferred because it has high spring properties.

Next, a seizure test and a wear test will be explained.

Martensitic stainless steel ll4sUs440B (0
．． 75 ~0.95%C, ≦1.0%Si, ≦1.0
%Mn, ≦0.040%P1≦0.030%S1≦0.
60%Ni, 16.0-18.0%Cr, ≦0.7
Prepare a sample material of 5%Mo (both weight%),
A 5 mm x 5 mm x 10 size test piece was taken from this {Jt sample material. Some of these test pieces were coated with a nickel alloy composite dispersion plating layer on the square end faces.
An iron alloy composite dispersion plating layer was formed on the other part of the square end face. The thickness of each plating layer was 100 μm, and after plating, heat treatment was performed at 400° C. for 1 hour.

The former plating bath uses a plating bath in which silicon nitride powder is suspended in an aqueous solution (plating solution) consisting of nickel sulfate, nickel chloride, cobalt sulfate, sodium hypophosphite, and boric acid, and the blending amount and nitriding bath are The structure and structure of the plating layer were changed by changing the particle size of the silicon powder.

The temperature of the plating bath was 50-53°C, and the current density was 8A/d.
rrr, the plating time was 2.5 hours, and the pH of the plating bath was set to a predetermined value between 2.0 and 3.0 according to the bath composition regulations.

Examples of the plating conditions and the composition and hardness of the plating layer are shown in Tables 1 and 2 below.

Table 2 The latter plating bath uses a plating solution in which silicon nitride powder is suspended in a plating solution consisting of ferrous sulfate, ferrous chloride, sodium hypophosphite, and boric acid. The blending amount and the particle size of the silicon nitride powder were varied. The temperature of the plating bath is 55
~57°C, current density 5A/dd, plating time 2.
For 5 hours, the pH of the plating bath is 2.6-2.8.

Examples of the plating conditions and the Ia and hardness of the plating layer are shown in Tables 3 and 4 below.

(The following are blank spaces) Table 3 Table 4 The following tests were conducted using cast iron FC25 for cylinder liners as a mating material that was slid relative to these test pieces.

The outline of the disaster cleaning cloth test device is schematically shown in FIG. 6 and FIG. 7, which is a sectional view taken along the line ■-■ in FIG. (1) Lubricating oil is applied to the center of the attached mating disc test piece 22 from the back side through the oiling hole 23. A pressing force P is applied to the stator holder 21 by a hydraulic device (not shown) at a predetermined pressure toward the right in the figure.

A rotor 24 is provided opposite to the disk test piece 22, and is rotated at a predetermined speed by a drive device (not shown). A test piece holder 24a attached to the end face of the I-kota 24 opposite to the disk test piece 22 has a square end face as a sliding surface, and four prismatic test pieces 25 are removable at equal intervals on a concentric circle. It is slidably attached to the disk test piece 22.

In such an apparatus, a predetermined pressing force P is applied to the stator 21, and a disc test piece 22 and a prismatic test piece 2 are separated by a predetermined surface pressure.
The rotor 24 is rotated while lubricating the sliding surface from the lubricating hole 23 at a predetermined lubricating speed.

The pressure acting on the stator 21 is increased stepwise at regular intervals, and the rotation of the rake 24 causes the prismatic test piece 25 to be
Torque (torque generated by frictional force) Tq generated on the stator 21 by the friction between the disk test piece 22 (12) is applied to the load cell 27 via the spindle 26, the change is read by the dynamic strain meter 28, and the change is read by the recorder. 29 to record. It is assumed that seizure has occurred when the torque Tq rapidly increases, and the quality of the seizure resistance is determined based on the magnitude.

The test conditions are as follows.

Friction speed: 8 m/sec Lubricating oil: Motor oil #30 at 400 mR/min. Contact pressure: 40 kg/c at the start of the test, then increased by 10 kg/c + fl every 3 minutes. Figures 6 and 7 A wear test was conducted using a test device under the following test conditions.

Friction speed is 5m/sec, contact pressure is 100kg/al
The lubricating oil is motor oil #30 and dust (JI
S2 types) 0.2g/I! ．． The additives and other test conditions were the same as in the seizure test described above.

The amount of wear was measured as follows. For the prismatic test piece, the test piece was removed after the test and the reduction in height due to wear (13) was measured. For the disk test piece, the depth of an annular wear scar caused by wear was measured.

The test results were as shown in FIGS. 8 to 14. From Figures 8 to 14, the base of the Niggel alloy plating layer is
A nickel alloy containing 2 to 10% phosphorus and 1O to 50% cobalt is used, and the silicon nitride particles dispersed in these bases have an average particle diameter of 5 μm or less, particularly 0.3 to 5 μm, and a dispersion amount of 5 to 5 μm. It can be understood that a good effect can be obtained by setting the phosphorus content to 30% by volume, and by setting the base of the iron alloy plating layer to 2 to 10% by volume. In these figures, the test time of the wear test is 50 minutes.

For comparison, a prismatic test piece (Comparative Example 1) with a hard chromium plating layer of 100 μm thick formed on the same base material was prepared.
A similar test was conducted on a prismatic test piece (Comparative Example 2) on which a nitrided layer of 00 μm was formed. The prismatic test pieces of these comparative examples were the same as the above-mentioned prismatic test pieces, with the base of the plating layer being 20% by weight cobalt, 5% by weight phosphorus, and the balance being nickel, and 0.3 to (14) 3 μm of SiJ4 was added to the base. One in which particles were dispersed at 10% by volume (Example 1), and one in which SiJ4 particles similar to those in Example 1 were dispersed in this base, with the base of the plating layer being 2% by weight phosphorus and the balance iron (Example 2). Figures 15 and 16 show a comparison with the test results. In addition, in Fig. 15, the fact that the surface pressure at which seizure occurs is located in the middle of the scale with intervals of 10 kg/cilT indicates that seizure has occurred while the contact surface pressure is rising, and is marked with hatching. The area shown represents the range of low and high values obtained in two identical tests.

Comparative Example 1 has the lowest seizure-generating surface pressure and the highest amount of wear. Comparative Example 2 has the smallest amount of wear and has improved seizure resistance compared to Comparative Example 1. On the other hand, in both Examples 1 and 2, the wear amount is close to that of Comparative Example 2, and the seizure resistance is further improved compared to Comparative Example 2.

Next, an actual machine test (Hench test) in which the oil scraper ring according to the present invention was assembled into an engine and operated was explained.

(15) As the oil scraper ring, one having a structure shown in an enlarged partial perspective view in FIG. 3 and an enlarged sectional view in FIG. 1 was used. This oil scraper ring was first proposed by the applicant (Utility Model Application No. 51112
No. 642).

The oil scraper ring 1 consists of a sliding member 2 formed by rolling a hard steel wire SWRH77B into an M-shaped cross section, and a stainless steel wire.
It consists of a coil expander 6 made of work-hardened ilsUs304. Parallel parts 2a, 2a of sliding member 2
A nickel alloy composite dispersion plating layer or an iron alloy composite dispersion plating layer 5A, 5A is formed on the end face of the cylinder, and these plating layers 5A, 5A slide against the cylinder liner (16 in FIG. 4). The same plating layer 5D as above is formed on the back surface of the valley-forming portion 2b (V-shaped cross section) of the sliding member 2, and an oil window for oil to pass through is formed at the bottom of the valley portion 2b. 4 are provided at equal intervals in the circumferential direction.

The above-mentioned plating layer is formed by stacking a large number of M-shaped base materials 3 in the vertical direction and electrolyzing the plating bath between them and the anode near the side wall of the plating bath while rotating in a plating bath using this as a cathode. 3 (IG) is formed. Therefore, no plating layer is formed on the outer surface of the parallel portion 2a where adjacent sliding members contact each other. As mentioned above, since the above-mentioned plating layer has good plating adhesion properties, the current flows inside the sliding member through the window 4, and the valley part 2
A plating layer 5D is also formed on the back surface of b to have a uniform thickness.

The thickness of the plating layer 5D is 175 to 1 of the thickness of the plating layer 5A.
/lO.

Further, a plating layer 5B is also formed on the inner surface of the parallel portion 2a and the outer surface of the valley portion 2b, and a plating layer 5C is also formed on the surface of the window 4. The above plating layer has the following composition. The nickel alloy composite dispersed plating layer has a structure in which 10% by volume of silicon nitride particles having a particle size of 3 μm are dispersed in a nickel alloy base containing 20% by weight of nickel and 5% by weight of phosphorus. The iron alloy composite dispersion plating layer consists of 5% by volume of silicon nitride particles with a particle size of 3 μm in an iron alloy matrix containing 2% by weight of phosphorus.
It has a dispersed structure.

In this example, the thickness of the plating layer 5A is 100 μm.
The thickness of the plating layer 5D is 15 μm for the nickel alloy composite dispersion plating layer, and 10 μm for the iron alloy composite dispersion plating layer (17). After plating, the sliding member 2 was heat-treated at 400°C for 1 hour. Figure 2A shows the structure of the nickel alloy composite dispersion plating layer at a magnification of 40
The micrograph at 0x magnification and Figure 2B are micrographs at 400x magnification showing the structure of the iron alloy composite dispersed plating layer. Gray silicon nitride particles are observed to be uniformly dispersed in the nickel alloy or iron alloy matrix. Note that Ni3P phase, NisSi phase, Fe. The P phase is so fine that it cannot be observed in photographs, but the presence of these phases has been confirmed by X-ray diffraction tests.

The surface of the base 7 of the coil expander 6 has a thickness of 10μ.
A hard chromium plating layer 8 of m was formed.

The oil scraper ring 1 has a nominal diameter of 86 mm, a width B of 4 mm, and a thickness T of 2.5 mm.

The above oil scraper ring was installed in a 4-stroke, water-cooled, 4-cylinder, 2000 cc diesel engine with a bore diameter of 86 mm, and was subjected to pen de-destination for 200 hours at full load at a rotation speed of 4750 rpm, and the amount of oil depleted was determined by Established.

Figure 4 shows the engine screws 1 to 1 ring and their surroundings (I
8) is an enlarged sectional view of. The piston 1 hem 13 is fitted into the cast iron cylinder liner 16, and the ring groove 14A of the piston 13 is inserted into the cylinder liner 16 made of cast iron.
, 14B, and 14C are equipped with a barrel face-shaped first pressure culling 11, a tapered face-shaped second pressure culling 12, and the above-mentioned oil scraper ring 1 in order from the top. In the oil scraper ring 1, the sliding member 2 is pushed from the back side by the coil expander 6, and is pressed against the inner circumferential surface of the cylinder liner 16 with high surface pressure. In the figure, 17 is a water cooling jacket.

The measurement results are shown in FIG. In the figure, for comparison, the plating layers 5A and 5D in Figure 1 have a thickness of 1
The results of similar tests on an oil scraper ring with a 00μm hard chrome plating layer (Comparative Example 1) and an oil scraper ring with a nitrided layer formed at the same location by gas nitriding (Comparative Example 2) are also listed. There is.

The oil consumption was good in the order of Example 1, Example 2, and Comparative Example 1, and there was almost no change in these after 50 hours of operation. In Comparative Example 2, the initial conformability of the nitrided layer was not good, so oil consumption gradually decreased until 100 hours of operation, resulting in a large amount of oil consumption.

In addition, examples in which chromium oxide (crzoz) particles were dispersed instead of the silicon nitride particles in Examples 1 and 2 (Examples 3 and 4)
Similar tests were conducted on examples (Examples 5 and 6) in which chromium carbide (Cr3C4) particles were also dispersed.
The oil consumption after 100 hours of operation was as shown in Table 5 below, indicating good results. The particle diameters and dispersion amounts of the chromium oxide particles and chromium carbide particles are the same as in Examples 1 and 2.

After 200 hours of operation, the depth of the recess formed on the back surface of the sliding member due to the biting of the coil expander was as in Examples 1 to 6.
In both cases, the thickness was 2 μm. On the other hand, in Comparative Example 1, the depth was 40 μm. In addition, in the case of the oil scraper ring in which the back surface of the sliding member was masked and the surface was covered with mother-of-pearl, the depth of the recess was 110 μm. From this result, in FIG. 5, it is determined that although the oil consumption of Comparative Example 1 is not much different from that of the Example, the oil consumption increases with longer operation.

From the results of the above seizure test, wear test, and actual machine test,
The oil scraper ring based on the present invention exhibits excellent seizure resistance and abrasion resistance, and has excellent durability.It also has good initial adaptability and exhibits a good oil supply function for a long period of time from the beginning of operation. , and low oil consumption, making it economical.

Note that the shape of the oil scraper ring is not limited to the above example; it may also be a plate expander that has two rails (sliding members), upper and lower, and a plate expander or sub-expander that pushes the rails from behind. Similar effects can be obtained by applying the present invention to an oil scraper ring with an expander or an oil scraper ring with a smooth expander.

fart. Effects of the Invention The present invention is characterized in that a plating layer having a structure in which hard ceramic particles are dispersed in a metal base is formed on the outer peripheral surface of the sliding part and the back surface of the elastic means (2l) (zU). Therefore, it shows excellent durability even under severe usage conditions due to the excellent seizure resistance and wear resistance due to the -12 structure of this plating layer, and In addition to good adhesion and abrasion resistance, it also has good initial run-in, so it performs a good lubricating oil supply function over a long period of time from the first engine operation, and consumes less lubricating oil.

[Brief explanation of drawings]

The drawings all show examples of the present invention, and FIG. 1 is an enlarged sectional view of an oil scraper ring, FIGS. 2A and 2B are micrographs showing the metal structure of the plating layer, and FIG. 3 Figure 4 is an enlarged partial cross-sectional view of the diesel engine with the oil scraper ring and pressure ring assembled, Figure 5 is a graph showing the results of actual machine tests, and Figure 6 is a graph showing the results of the actual engine test. The main parts of the equipment for wear tests and abrasion tests (2
2) A partially fractured schematic diagram shown in Figure 7 is a sectional view taken along the line ■-■ in Figure 6, Figures 8, 9, 10, 11, 12, 13, and 14th
Figure 15 is a graph showing the relationship between the strength of the plated layer and seizure resistance or wear resistance. Figure 15 is a graph showing the results of the seizure test in comparison with a comparative example. It is a graph showing the results in comparison with a comparative example. In addition, in the symbols shown in the drawings, 1... Oil scraper ring 2... Sliding member 3... Sliding member. Base material 4...Oil windows 5A, 5B, 5C, 5D, 25a...Plating layer 6...Coil expander 7... ...
...Coil expander base material 8...
・Hard chrome plating layer (23) 11, 12... Pressure ring 13...
... Piston 16 ... Cylinder liner 21 ...
...Stator 22...Disc test piece (mating sliding test piece)
23... Oil filling hole 24... Rotor 25... It is a prismatic test piece.

Claims (1)

[Claims] 1. In an oil scraper ring consisting of a sliding part that slides against the inner circumferential surface of the cylinder and an elastic means that presses the sliding part from behind, the outer circumferential surface of the sliding part and the elastic means contact with each other. An oil scraper ring characterized in that a plating layer having a structure in which hard ceramic particles are dispersed in a metal base is formed on the back surface of the sliding part.