CN201031737Y - A wear-resistant hard chrome plated piston ring - Google Patents

Abstract

The utility model pertains to an internal-combustion engine piston ring, in particular to a wear-resistant hard chromium-coated piston ring. According to the technical proposal provided by the utility model, the wear-resistant hard chromium-coated piston ring includes a ring-shaped matrix with an opening. The utility model is characterized in that the external spherical surface of the ring-shaped matrix has at least two hard chromium coating layers and the hard chromium coating layer is provided with reticulated cracks for oil storage and lubrication. The utility model can improve the eccentric wear of the piston ring and the wear-resistant performance of the hard chromium coating layer, decrease the internal stress of the coating layer, increase the fatigue and fracture resistant performance of the piston ring and further extend the service life of the piston ring.

Description

A wear-resistant hard chrome plated piston ring

technical field

The utility model belongs to a piston ring of an internal combustion engine, in particular to a wear-resistant hard chrome plated piston ring.

Background technique

At present, the wear-resistant functional coating of internal combustion engine piston rings of railway locomotives in my country only has ordinary electroplating hard chromium layer, which is continuously electroplated in a solution containing chromium trioxide and sulfuric acid. It is a single-layer structure, and the thickness of the hard chromium coating is generally 0.10~ 0.35mm, the composition is chromium with a small amount of H and O adsorbed. Due to the existence of H, the coating produces internal stress, which makes the hard chromium coating appear reticular microcracks with a width of less than 0.2μm. The hardness of the hard chromium coating is 800-1100HV0.1, which has good wear resistance. However, when the piston ring is working, it is often caused by partial wear due to excessive local force and accelerated local wear. In addition, when the thermal load and/or mechanical load exceeds its bearing limit, the lubricating performance of the original ordinary hard chrome coating will deteriorate, and in this case, it is easy to cause adhesive wear and even cylinder scuffing.

Contents of the invention

The purpose of the utility model is to design a wear-resistant hard chromium coating piston ring, to improve the eccentric wear phenomenon of the piston ring, improve the friction and wear performance of the hard chromium coating of the piston ring, reduce the internal stress of the coating, and improve the fatigue fracture resistance of the piston ring, thereby Increase the service life of piston rings.

According to the technical solution provided by the utility model, the wear-resistant hard chromium coating piston ring includes an annular base with an opening, and is characterized in that: there are at least two layers of hard chromium coatings on the outer surface of the annular base, and the hard chromium coatings are distributed There are network cracks that can be used for oil storage lubrication.

The width of the network cracks on the hard chromium plating layer is 0.2-10 microns, and the crack density is 40-150 cracks/mm.

Preferably, the width of the network cracks on the hard chromium plating layer is 0.5-5 microns, and the crack density is 50-80 cracks/mm.

When the piston ring is working, it is often caused by partial wear due to excessive local force and accelerated local wear. The original ordinary hard chromium coating is not strong enough due to excessive wear, which affects the performance of the piston ring and even causes the piston ring to break;

When the layered oil-storage hard chromium-plated piston ring of the utility model is eccentrically worn, due to the multi-layered oil-storage cracks at the eccentrically worn part, the lubricating ability is increased, thereby slowing down wear and preventing excessive wear of the piston ring. Ensure the performance of the piston ring.

In the piston ring/cylinder liner friction system, when the thermal load/mechanical load on the piston ring is too large, the lubricating oil film on the cylinder liner wall nearly disappears, and the friction state is semi-dry friction or even dry friction. The original ordinary hard chrome The coating is prone to adhesive wear, and even the cylinder is pulled, but the lubricating oil stored in the reticular cracks of the piston ring coating of the utility model will be continuously replenished to the cylinder liner wall at this time, and the oil film on the friction surface is repaired, thereby avoiding the ring and the cylinder liner. Adhesive wear and even cylinder pulling.

The utility model has the advantages of: due to the layered structure of the multi-layer hard chrome coating; and each layer is distributed with reticular cracks that can be used for oil storage and lubrication; in the piston ring/cylinder liner friction system, when the piston ring wears down When the first layer is formed, the network cracks that store lubricating oil are revealed, thereby slowing down the wear of the working surface of the piston ring, improving the performance of the piston ring, and prolonging the service life of the piston ring.

When the ordinary hard chrome plating of the piston ring is carried out, due to the large internal stress caused by the penetration of hydrogen into the plating layer, stress cracking may occur during work, and the cracks become fatigue sources and cause fatigue fractures;

The hard chromium coating of the piston ring provided by the utility model is composed of multiple layers, and each layer has a stress relief process, so the internal stress of the coating is smaller than that of the ordinary hard chromium coating piston ring, thereby improving the fatigue strength of the piston ring and strengthening the piston ring. ring fatigue fracture resistance.

Description of drawings

Fig. 1 is a structural schematic diagram of the utility model piston ring, and its outer circular surface is a new wear-resistant hard chromium coating.

Fig. 2 is a schematic diagram of the A-A section structure in Fig. 1 .

Detailed ways

As shown in the figure: the wear-resistant hard chromium coating piston ring includes an annular base 1 with an opening, and there are at least two layers of hard chromium coating 2 on the outer circular surface of the annular base 1 (the surface that is in sliding contact with the cylinder block). The chrome plating is distributed with reticular cracks that can be used for oil storage lubrication.

During production: First, a layer of hard chrome is electroplated on the piston ring base 1, and then the microcracks on the hard chrome coating are expanded to the required width of 0.2-10 microns by physical and chemical means of corrosion. The cracks are distributed in a network with a density of 40- At the same time, the H part contained in the coating is released, the internal stress of the coating is reduced, and a single-layer crack oil storage coating is obtained. The thickness of the single-layer coating is not less than 0.015mm, and the second single-layer crack storage is carried out in the same way. The oil coating is produced, and so on, until the coating reaches the desired thickness (Figure 3).

The utility model has the following characteristics:

(1) Reduce the internal stress of the coating and improve the fatigue strength of the piston ring

When the micro-cracks on the hard chromium coating are expanded, the hydrogen contained in each coating is partially released, reducing the internal stress of each hard chromium coating, thereby improving the fatigue strength of the piston ring and improving its fatigue fracture resistance.

(2) Improve the eccentric wear of the piston ring

When the piston ring is subjected to excessive local force and local wear is accelerated to cause eccentric wear, the original ordinary hard chrome coating has insufficient strength due to excessive wear, which affects the performance of the piston ring and even breaks. The chrome-plated piston ring has multi-layer oil storage cracks in the eccentric wear part, which slows down the wear, thereby preventing excessive wear of the piston ring and ensuring the performance of the piston ring.

(3) The friction and wear performance of the hard chrome coating of the piston ring is improved to avoid adhesive wear and even cylinder scuffing

In the piston ring/cylinder liner friction system, when the thermal load/mechanical load on the piston ring is too large, the lubricating oil film on the cylinder liner wall nearly disappears, and the friction state is semi-dry friction or even dry friction. The original ordinary hard chromium coating is prone to adhesive wear, and even the cylinder is pulled, but the lubricating oil stored in the reticular cracks of the piston ring coating of the utility model will be replenished to the cylinder liner wall at this time, and the oil film on the friction surface is repaired, so that the ring can be avoided. Adhesive wear with the cylinder liner and even the cylinder.

Claims (3)

1. A wear-resistant hard chromium coating piston ring, comprising an annular substrate with an opening, characterized in that: there are at least two layers of hard chromium coatings on the surface of the annular substrate, and the hard chromium coatings are distributed on the hard chromium coatings that can be used for oil storage lubrication. network of cracks. 2. The wear-resistant hard chromium-coated piston ring according to claim 1, characterized in that: the width of the network cracks on the hard chromium coating is 0.2-10 microns, and the crack density is 40-150 cracks/mm. 3. The wear-resistant hard chrome plated piston ring according to claim 1 or 2, characterized in that: the width of the network cracks on the hard chrome plated layer is 0.5-5 microns, and the crack density is 50-80 cracks/mm.

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