JPH03260089A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the durability of an internal combustion engine by burying the powder of hard material particles into the inner peripheral surface of a cylinder liner and dispersing after hard material fine particles in the Ni-P alloy plating layer on the outer peripheral surface of piston ring. CONSTITUTION:The powder of particles of hard material, such as SiC, Al2O3, Cr2O3 and Si3N4, is buried into the inner peripheral surface of the cylinder liner of internal combustion engine by the method similar to lapping, etc. The compound plating layer consisting of Ni-P or Ni-Co-P alloy in which at least one kind of hard fine particles of metal carbide, metal nitride, metal oxide, etc., are dispersed is provided at least on the outer peripheral surface of the piston ring made of cast iron or steel. By this method, the multiple dispersion plating layer forming sliding surface is strongly adhered to the ring material, and the falling-off or exfoliation of the compound dispersion plating layer is eliminated, and the abrasion of side surface of piston ring is prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an internal combustion engine with improved durability.

(Prior art) Since modern internal combustion engines have high output and high rotation speed, wear of the inner circumferential surface of the cylinder liner and the outer circumferential surface of the piston ring attached to the piston that slides on this inner circumferential surface is a problem. It becomes. That is, when an internal combustion engine is rotated at high speed, early wear occurs on the inner circumferential surface of the cylinder and/or the outer circumferential surface of the piston ring, which deteriorates the durability of the internal combustion engine.

In order to prevent such early wear, the cylinder liner is made of cast iron or mild steel, and SiC powder is embedded in the surface of the cylinder liner by a technique similar to known wrapping.

SiC is a hard particle, and by distributing this hard particle on the inner peripheral surface of the cylinder liner, wear resistance is improved. This kind of improvement of the cylinder liner was made in 1986.
For example, Japanese Patent No. 8309 discloses a method in which, when lapping a cylinder liner, a slurry containing hard particles is injected into the cleaning liquid, and the hard particles are permanently embedded in the liner surface using a cleaning blade. Ru.

Improving the wear resistance of the inner circumferential surface of the cylinder liner accelerates the wear of the outer circumferential surface of the piston ring that slides on the inner circumferential surface.

Therefore, by plating the outer circumferential surface of the piston ring with Cr, the wear resistance of the outer circumferential surface of the piston ring is improved. Improvements to the outer peripheral surface of piston rings include, for example,
JP-A-56-127413 discloses a means for embedding high-hardness particles such as Si particles on the outer circumferential surface of a piston ring by a wrapping method, and JP-A-1-159449 discloses a means for embedding high-hardness particles such as Si particles on the outer circumferential surface of a piston ring. A means of providing a nitrided layer is disclosed.

Furthermore, various attempts have been made to find an optimal combination of improved cylinder liners and piston rings. For example, JP-A-59-265187 teaches the combination of a liner with dispersed embedded hard particles and a thermal spray ring.

(Problems to be Solved by the Present Invention) Apart from the above-mentioned combination of a cylinder liner and a piston ring, the most common combination of a cylinder liner with SiC powder embedded in its surface and a piston ring with a Cr plating layer. A wear test was conducted using the apparatus shown in FIG.

As shown schematically in Figure 1, the wear resistance test device and test method are as follows:
The test was carried out using a rotary abrasion tester using a drum embedded with iC powder and a 30 μm thick Cr-plated test piece.

The test results are shown in Figure 2.

The test method is to support a lever 3 at a fulcrum 6, attach a weight 4 and a balancer 5 to both ends, and test a test piece 1 attached to the lever 3.
was brought into pressure contact with the inner circumferential surface of the rotating drum 2, keeping the surface pressure constant, and the drum 2 was rotated while lubricating oil was supplied between the test piece 1 and the drum 2 from the lubricating oil tank 7, and the test was carried out by rotating the drum 2. The wear thickness (μm) of Piece 1 was measured. The drum 2 rotates in response to the rotational torque of the drive roller 8.
The center of rotation is maintained by the three-point support of the pair of guys 1 to 9 and the drive roller 8.

Test conditions Friction speed: 0.25m/s Friction time = 3 hours Weight: 2kg Lubricating oil: Motor oil #30 Supply amount: 10cc10+1n The combination of a cylinder liner embedded with SiC powder and a piston ring coated with Cr is as follows: Although it is thought to have excellent wear resistance, in reality, as shown in Figure 2, the SiC powder acts as an abrasive and wears down the Cr plating layer, causing piston rings to wear out quickly. , leaving problems with the durability of internal combustion engines.

Therefore, it is an object of the present invention to solve the above-mentioned problems of the prior art.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention basically consists of applying a nickel-based composite plating layer in which oxides and hard particles are dispersed to the outer peripheral surface of a piston ring. More specifically, the present invention uses a technical means of embedding hard material powder into the inner circumferential surface of the cylinder liner. In internal combustion engines, powder of hard material particles is embedded in the inner peripheral surface of the cylinder liner, and at least the outer peripheral surface of the cast iron or steel piston ring is coated with Ni-P or N.
Provided is an internal combustion engine having a composite plating layer in which one or more types of hard fine particles such as metal carbide, metal nitride, metal oxide, etc. are dispersed in the i-Co-P alloy plating layer.

Preferably, the powder embedded in the cylinder liner is Si
Provided is a combination internal combustion engine of one or more types selected from the CXA1z03, CrzO, 5t3Na OD group.

As a dispersant for the alloy plating layer, A f , 03, Cr
zOz, TiO2, SIC,, TIN% Cr3C2,
BNlWC.

Known dispersed particles such as SiO□ are used.

(Function) During high-speed rotation of the piston, the hard material particles embedded in the inner peripheral surface of the cylinder liner crystallize with the hard material particles compositely dispersed on the outer peripheral surface of the piston ring, forming a highly hard Ni-based alloy plating layer. The matrix 7x layer prevents abrasive wear without acting as an abrasive, reducing the amount of wear on the outer circumference of the piston ring. In particular, by uniformly dispersing fine particles of hard powder in the coating layer, it is possible to disperse and strengthen the coating and at the same time prevent contact between metals.

In the present invention, preferably, a Ni-P or Ni-Co-P alloy hard material particle composite dispersed plating layer is provided on the base layer consisting of a nickel-plated strike layer on the outer peripheral surface of the piston ring. The adhesion between the ring material and the composite dispersion plating layer forming the sliding surface is very good.

Furthermore, even when a nitrided layer is provided on the ring material in order to improve durability, the adhesion to the ring material is very good. Therefore, Ni-P system or Ni-C.

- There is no occurrence of dropping or peeling of the P-based alloy hard particle composite dispersed plating layer.

(Example) (1) SiC, AlzOs, CrzO3, Si
One or more powders of 3N4 were embedded using a technique similar to wrapping. That is, the drum was placed within the cylinder via a plurality of spring-loaded wrap vanes. Rotate the cylinder and these lamp blades (170r
ρm) and reciprocating motion (5 cycles per minute). 220
Using a working fluid mixed with mesh SiC, lapping was performed for 1 minute. Next, the liner was lapped for 1 minute using a working fluid mixed with 400 mS of SiC, and the protruding tip of the SiC embedded in the inner circumferential surface of the liner was cut off to form a flat surface. SiC was embedded in about half of the inner peripheral surface of the liner.

After forming nickel strike plating on a plurality of test pieces made of 5US440B, which is the base material of piston rings, the following treatment was performed to obtain test pieces (1) and (2).

Test piece I Plating time 2 Hr Dispersed particles Knee 〇, 5 μm particle size Dispersion density 20 g/A Test piece ■ Bath & 11 precepts and plating conditions and test piece Same as ■: Dispersed particles
: CrzO35μm particle size dispersion density 20g
/f Test specimens I and (2) were prepared, each having a 100 μm composite plating layer in which hard material particles (WC, CrzO, . . . ) were dispersed in a matrix of a Ni-P or Ni-Co-P alloy plating layer.

The drum 2 and test piece 1 thus manufactured were tested using the testing apparatus shown in FIG.

The results are shown in FIG.

As is clear from FIG. 2, the wear resistance of test pieces (1) and (2) corresponding to piston rings is 4 to 5 times higher than that of the conventional Cr-plated pieces. That is, the durability is 4 to 5 times that of the conventional one.

Drum 3 showed almost no wear, with only a few traces remaining.

(2) Prior to the aforementioned N+P-based or Ni-Co-P-based alloy plating composite dispersion plating treatment, the piston ring base material made of 5US440B is left in a nitriding gas atmosphere for several hours to form a nitrided layer on at least its surface. After that, nickel strike plating was applied, and then tungsten carbide powder particles with a diameter of 5 μm were added to the Ni-P or Ni-Co P alloy plating layer described above.
Test specimens I and (2) were prepared with a composite dispersed layer consisting of a composite dispersed particle size and a chromium oxide powder particle size 5 μm. The thickness of each composite dispersion plating layer is 50 um, and the hardness is HmV850 due to heat curing treatment.

This test piece 1 was combined with the drum 2 described above, and a test was conducted using the apparatus shown in FIG. As a result, there was no occurrence of peeling or cranking of the plating during the test, there was no problem with the coating treatment on the nitrided layer, and the wear effect was found to be equivalent to that of Example (1).

This example is effective in preventing the rapid progress of wear of the base material after the plating has disappeared, and also in preventing side wear of the piston ring.

[Brief explanation of drawings]

FIG. 1 is a front view of the wear test device, FIG. 2 is a side view thereof, and FIG. 3 is a graph showing the test results. In the figure: 1... test piece, 3... drum, 4... weight, 6... fulcrum, 8... drive roller, 9... guide roller. Agent Hideaki Kuwahara, patent attorney

Claims (3)

[Claims] (1) In an internal combustion engine in which the outer circumferential surface of a piston ring attached to a piston slides into contact with the inner circumferential surface of the cylinder liner, a powder of hard material particles is embedded in the inner circumferential surface of the cylinder liner, and a piston ring made of cast iron or steel is used. At least on the outer peripheral surface, a composite plating layer in which one or more types of hard fine particles such as metal carbide, metal nitride, metal oxide, etc. are dispersed in a Ni-P-based or Ni-Co-P-based alloy plating layer. internal combustion engine. (2) The powder embedded in the cylinder liner is SiC, A
Claims consisting of one or a combination of two or more selected from the group l_2O_3, Cr_2O_3, Si_3N_4 (
1) Internal combustion engine. (3) The internal combustion engine according to claim (2), wherein a nickel strike plating layer or a nitride layer is provided as a base layer of the composite plating layer, and the alloy plating layer is subjected to a heat hardening treatment.