JPH017721Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to cylinder liners for internal combustion engines such as diesel engines. In internal combustion engines such as conventional diesel engines,
By cooling the outer circumferential surface of the cylinder liner with cooling water or the like, the cylinder liner is prevented from becoming extremely hot. For this reason, about one-third of the combustion energy is lost due to heat radiation due to the cooling, resulting in a decrease in output. This idea was made in view of these circumstances,
Provides a cylinder liner for internal combustion engines that has improved heat resistance by thermally spraying chrome carbide on the surface of the liner body, thereby reducing heat loss due to cooling and increasing thermal efficiency, thereby increasing the output of internal combustion engines. It is. This invention will be described in detail below with reference to an illustrated embodiment. In the figure, reference numeral 1 denotes a liner body made of cast iron, and in order to improve high-temperature wear resistance, chrome carbide is thermally sprayed on the inner surface to form a high-temperature wear-resistant layer 2. 60 to 90 to form the above high temperature wear-resistant layer 2
% by weight of chromium carbide and the balance Ni-Cr or Ni-Co or Co are appropriately mixed, this is plasma sprayed onto the liner body 1, and the sprayed area is then finished to a thickness of 3μ or less, resulting in high-temperature wear resistance. Layer 2 has a hardness of Hmv350-700.
The amount of chromium carbide is preferably 75% by weight, but good results can be obtained when it is preferably in the range of 60 to 90%. If it is less than 60%, the abrasion resistance will decrease, and if it is more than 90%, the degree of bonding of the film will be weak, so the abrasion resistance will deteriorate. On the other hand, by spraying chromium carbide, a large number of fine pores are formed in the high-temperature wear-resistant layer 2, and these pores become oil reservoirs and contribute to lubrication, so that the lubrication performance does not deteriorate even at high temperatures. Next, the results of the wear resistance test and seizure resistance test of the liner body 1 obtained above will be explained. First, regarding the abrasion resistance test, as shown in Fig. 2, the liner body 1 to be tested is rotatably mounted in a heating furnace 3 with a closed structure, and a lever 5 with a weight 4 hanging from one end of the liner body 1 is used. The ring material 6 is pressed. The ring material 6 is made of iron-based material plated with titanium carbide, and the liner body 1 is heated while maintaining the inside of the heating furnace 3 at a temperature of 450°C.
The test was conducted by rotating at a speed of 1 m per second. As a result, the wear of chrome carbide 2 was as shown in the table below. For comparison, similar tests were conducted on cast iron, hard chrome-plated materials, and alumina-sprayed materials, and the results were as shown in the table below.

[Table] Next, to explain the seizure resistance test, a disk-shaped sample on which a high-temperature wear-resistant layer 2 was formed under the same conditions as the liner body 1 was attached to the fixing member 7 as shown in FIG.
A sliding member 8, which is assumed to be a piston ring, is sprayed with titanium carbide to a thickness of 0.3 mm and has a surface roughened to a roughness of 1.5 to 2 μm.The sliding member 8 is attached to the rotating body 9, and is brought into pressure contact with the sample. It was rotated at a speed of 8 m/s, and the sliding parts were lubricated. Further, the friction torque of the sliding portion due to the rotation of the rotating body 9 was measured using a load cell 10 as shown in FIG. The results were as shown in Figure 5a.
Similarly, alumina sprayed samples b and c, hard chrome plating sample d, and silicon carbide baked body e were tested, and the results were shown in Figures 5 b to e.
As shown in FIG. 2, it has become clear that this invention provided with the high-temperature wear-resistant layer 2 is extremely superior. As mentioned above, this idea forms a high-temperature wear-resistant layer by thermally spraying chrome carbide on the inner surface of the liner body, which dramatically improves wear resistance and seizure resistance, as well as being able to withstand high temperatures. Therefore, a cylinder liner that does not require water cooling can be obtained. This makes it possible to reduce heat loss caused by water cooling, and at the same time, increase engine output by improving thermal efficiency.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; Fig. 1 is a partially enlarged sectional view of a cylinder liner, Fig. 2 is an explanatory diagram of a wear test, and Figs. 3 and 4 are explanatory diagrams of a seizure resistance test. , FIG. 5 is a diagram showing the results of the burn-in test. 1 is the liner body, 2 is the high temperature wear resistant layer.

Claims (1)

[Scope of utility model registration request] From 60% to 90% chrome carbide by weight%
A cylinder for an internal combustion engine in which a high-temperature wear-resistant layer 2 is formed on the inner surface of the liner body 1 by mixing Ni-Cr, Ni-Co, or Co and plasma spraying the mixture on the inner surface of the liner body 1 made of cast iron. Raina.