JPH10246146A - Cylinder liner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder liner having a high abrasion resistance and a good sliding capability with a high strength and with manufacture at low costs by padding-welding a cast iron padding material having a high sliding capability within a range of a predetermined length from at least a linear upper end of an inner surface in a steel made liner main body. SOLUTION: In a two layered cylinder liner 10 for a diesel engine, a cast iron family padding material having a high sliding capability is padding-formed on an inner surface of a liner upper part 3 for constituting a liner main body 1. A cast iron family material such as a perlite family is used as the padding material of the padding part 2. The padding is carried out in a predetermined thickness (t) by means of powder plasma padding welding with a predetermined thickness t from an liner upper surface 5 of an inner side of the liner upper part 3. The length L is set so that the lower end thereof is a position which is brought into sliding contact with an outer surface of a first stage piston ring where a piston is at a top dead point. After the padding part 2 is formed, the inner surface 4 of the cylinder liner 10 is finished to a predetermined size by means of polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-layer cylinder liner used for an internal combustion engine, particularly a large diesel engine.

[0002]

2. Description of the Related Art A cylinder liner for a large diesel engine has recently been developed to have high durability against thermal stress and high temperature from an upper high temperature part to a lower low temperature part as the large diesel engine has a longer stroke with a higher output. It is required to have high wear resistance and good slidability over the entire length.

[0003] In order to meet such demands, conventionally, as the cylinder liner, an integrated liner made of cast iron is subjected to heat treatment by laser quenching, or alloy steel having high strength and high wear resistance. A two-layer liner or the like in which an inner layer material made of the above material is joined to an inner side of an outer layer material made of a cast iron material by HIP (Hot Compression Bonding) processing,
It has been put to practical use.

[0004]

However, the integrated liner that has been subjected to the laser quenching treatment has recently been required to have a high output,
It does not have enough strength and wear resistance to support long strokes. Further, the two-layer liner formed by the HIP bonding as described above has high strength and abrasion resistance, but the manufacturing process is complicated and requires a large number of manufacturing steps.
There is a problem to be solved such as the necessity of a device for P-joining, which makes the manufacturing device complicated and expensive.

Accordingly, the present invention is easy to manufacture, reduces the number of manufacturing steps, and simplifies the manufacturing apparatus, can be manufactured at low cost, and has high strength, high wear resistance and good sliding properties. It is an object to provide a cylinder liner having:

[Means for Solving the Problems]

[0006] In order to solve the above-mentioned problems, the present invention is configured such that a high-slidability cast iron-based overlay material is weld-welded at least over a predetermined length from the upper end of the liner on the inner surface of the steel liner body. We propose a cylinder liner characterized by being done.

Here, as the high slidability cast iron-based overlay material, high C (carbon) -high Si (silicon) having high slidability is used.
-A ferrite-based or pearlite-based cast iron material having a high build-up weldability is preferred for the Fe (iron) -based base material.

The overlay welding is most suitably performed by powder plasma welding. According to an experimental example for a cylinder liner for a large diesel engine, the overlay welding amount is 10 to 15 kg / H. With high efficiency, the dilution rate is 10
~ 15% or less, which is very low, and good welding performance is obtained.

According to the invention, a high-strength high-C-high-Si-Fe-based cast iron material or the like having high strength, high wear resistance and good slidability is provided on the inner surface of the upper portion of the liner which is subjected to a high thermal load at a high temperature. Since the slidable cast iron material is build-up welded, the thermal fatigue strength of the upper part of the liner is improved, and the inner surface of the upper part of the liner, which becomes hot, has high wear resistance. A cylinder liner having sliding performance can be obtained.

In addition, it is possible to manufacture a two-layer cylinder liner with an extremely simple process and a small number of man-hours by performing build-up welding such as powder plasma build-up welding only on the upper inner surface of a steel liner body. Compared to a conventional two-layer cylinder liner by HIP bonding, a two-layer cylinder liner can be manufactured with a simpler and greatly reduced apparatus cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 is a cross-sectional view taken along an axis showing a state in which a two-layer cylinder liner for a diesel engine according to an embodiment of the present invention is mounted. In FIG. 1, 10 is a cylinder liner,
Reference numeral 11 denotes a jacket, and 12 denotes a coolant chamber formed between the outer surface 6 of the cylinder liner 10 and the jacket 11 and containing a coolant.

The cylinder liner 10 is provided with a high-slidability cast iron-based overlay material on the inner surface of a liner upper portion 3 constituting a liner body 1 made of a steel material such as an alloy steel having wear resistance and corrosion resistance. It is configured. Reference numeral 2 denotes the overlay. As the high slidability cast iron-based overlay material, from the viewpoint of high thermal fatigue strength and wear resistance, good slidability, and ease of production and low cost, high C (carbon) -high Si (silicon) is used. )
-A ferrite-based or pearlite-based cast iron material is used as the Fe (iron) -based base material.

The build-up of the build-up material is a low dilution welding method in which the powder main body of the build-up material is spread over a predetermined length L from the liner upper surface 5 inside the liner upper part 3 of the liner body 1. This is performed over a predetermined thickness t by powder plasma overlay welding. The length L is a position where the lower end of the piston L is slidably contacted with the outer surface of the first-stage piston ring (not shown) at least at the top dead center of the piston. The thickness t is determined by the inner diameter of the cylinder liner 10, the specifications of the engine to be used, the strength of the overlay 2, the workability of the overlay, and the like.

After forming the overlay portion 2 by the powder plasma overlay welding, the inner surface 4 of the cylinder liner is finished to a predetermined size by polishing or the like.

The cylinder liner 1 constructed as described above
In the case of No. 0, the inner surface 4 of the liner upper part 3 was formed by powder plasma overlay welding of a high C-high Si-Fe cast iron material. More than twice as much as the integrated cylinder liner,
The wear resistance of the inner surface 4 of the liner on which the piston ring slides at a high temperature is improved as well as greatly increasing. Furthermore, since it is a cast iron-based material, the familiarity with the piston ring, that is, the slidability is also improved.

Further, such a powder plasma overlay welding method comprises:
According to the experiments of the inventors, as a target of a cylinder liner for a large diesel engine, the build-up deposition amount is 10 to 15 kg / H.
With high efficiency, the dilution rate is extremely low, 10-15% or less,
Good weldability is obtained. Moreover, since powder plasma overlay welding only needs to be performed on the inner surface of the upper portion 3 of the liner, the cylinder liner can be manufactured with an extremely simple manufacturing method and with a small number of manufacturing steps as compared with the conventional two-layer cylinder liner. it can. As a result, a two-layer cylinder liner whose manufacturing cost is significantly reduced as compared with the conventional two-layer cylinder liner can be obtained.

[0018]

As described above, according to the present invention, a high carbon steel having high high-temperature strength, high abrasion resistance and good sliding properties is provided on the inner surface of the upper portion of the liner which is subjected to a high temperature and high repetitive thermal load. -Since high-sliding cast iron materials such as high Si-Fe cast iron materials are welded by build-up welding, the thermal fatigue strength of the upper part of the liner is improved and the inner surface of the liner, which is hot, has high wear resistance and slidability. As a result, a cylinder liner having high strength and high sliding performance suitable for a large diesel engine can be obtained.

In addition, it is possible to manufacture a two-layer cylinder liner in an extremely simple process and with a small number of man-hours by performing build-up welding such as powder plasma build-up welding only on the upper inner surface of the steel liner body. , Conventional HIP
As compared with a two-layer cylinder liner by joining, a two-layer cylinder liner whose manufacturing cost is greatly reduced can be obtained by a simple manufacturing method.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of a cylinder liner for a diesel engine according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liner main body 2 Overlay part 3 Liner upper part 4 Inner surface (sliding surface) 5 Liner upper surface 10 Cylinder liner

Claims (1)

[Claims] 1. A cylinder characterized in that a high-slidability cast iron-based overlay material is weld-welded over at least a predetermined length from the upper end of the liner on the inner surface of the steel liner body. Liner.