JPS5848723B2 - Kaiten piston engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary piston engine having an improved sliding member, and more specifically, rotano-using with porous chrome plating on the sliding surface and carbide deposited within a certain range. It relates to a rotating piston engine that is combined with a white cast iron Avex seal.

In a rotating piston engine, an avex seal is attached to the top of the rotor, and is pressed against the sliding surface of the trochoidal rotor housing by spring pressure, gas pressure, and centrifugal force, and slides. Since the part is shaped with a small radius of curvature, it comes into line contact with the sliding surface of the rotano housing, which increases the surface pressure and makes it difficult to form an oil film. There is a big difference between the sliding movement between the cylinder and the piston ring, and the sliding member must be considered from a completely different perspective.

Conventionally, various combinations of various materials have been attempted as sliding members for rotary piston engines, but a fully satisfactory combination of materials has not yet been obtained.

The combination of a chrome-plated rotor housing and a graphite Avex seal, which is said to have been relatively successful, is excellent in preventing scuff and chatter marks, but under high-speed, high-horsepower operating conditions, the Avex seal is wear progresses rapidly.

Furthermore, graphite has insufficient reliability due to its lack of mechanical strength, and cannot be used in two-piece or three-piece type avex seals, which are particularly effective in gas shielding, because the sharp edges tend to break.

For the above reasons, recently, self-lubricating Avex seals made of sintered alloys, Avex seals made of acicular cast iron or chilled castings, etc. have been proposed, but none of them are sufficient in terms of scuff resistance.

As a result of various studies on combinations of sliding members that eliminate the above-mentioned drawbacks, the inventors of the present invention have developed a metal Avex Seal by applying porous treatment to the chrome plating on the sliding surface of the Rotano Uging to give it oil retention properties. It has been found that when this method is adopted, the occurrence of Skasof is significantly reduced, and the occurrence of corrugated irregularities due to wear known as chatter marks that occur on the sliding surface of the rotano housing is also reduced.

In particular, when used in combination with Avex Seal made of white cast iron with a structure in which free carbide, which becomes a hard spot, is precipitated, almost no scuffing is observed, and there are only a few chatter marks. It was also found that there was little wear on the upper avex seal.

The porosity of the porous chrome plating applied to the sliding surface of the rotor housing is 5 to 40% as measured by the line integral meter method, and the free carbide uniformly distributed in the Avex seal material is measured using the same line integral method as above under the microscope field. 30-70 as measured by the meter method
It has been found that white cast iron with a structure having an area ratio of 1.5% is optimal.

If the porosity of the porous chrome plating layer is less than 5%, the oil retention is insufficient, and scuffs and chatter marks are observed to occur, and if the porosity exceeds 40%, the plating layer tends to wear out as described below. This is not desirable.

On the other hand, Avex seal materials with free carbide with an area ratio of less than 30% lack hardness, and wear of the Avex seal increases significantly during operation at high speeds and high loads, and when the area ratio of free carbide exceeds 70%, The material becomes extremely brittle, making it impractical.

Next, examples of the present invention will be described.

Example 1 The sliding surface of the trochoidal rotor housing of a 2X33QCC rotary piston engine is coated with porous chrome plating, and the rotor facing this is made of white cast iron with a structure in which free carbide is uniformly distributed at an area ratio of 40%. (Chemical composition: 3.4%C, 1.5%Si, 0.55%Mn, 0
．． 25%P,■. 8% Cr, 3% Mo) Avex seal was installed and the engine was heated at 6000r. p. m. After continuous operation for 50 hours, changes in the wear condition due to the porosity of the chromium plating layer were investigated by measuring the sliding surface roughness and the maximum amplitude of chatter marks.

FIG. 1 shows the microscopic structure of the Avex seal material used in the test.

The base is barlite, with a structure in which free carbide is precipitated in the form of white islands.

Figure 2 shows the results of measuring the surface roughness by scanning the sliding surface of the rotor housing after 50 hours of operation with the stylus of a roughness meter in a direction perpendicular to the sliding direction.

When the porosity is O, that is, no porous treatment is performed, scratches due to scuffing as deep as 18 microns are observed, and when the porosity is 3.5%, this decreases to about 8 microns, and when the porosity is 7.5%. %, 15%, and 25%, the surface roughness maintains the roughness of the finished surface before operation, and no scratches are observed.

Similarly, FIG. 3 shows the results of measuring the occurrence of chatter marks by scanning the stylus of a roughness meter in the sliding direction of the sliding surface of the rotor housing after 50 hours.

When the porosity is O, the chatter mark is large and waves as deep as 26 microns are observed, and when the porosity is 3.5%, this is 10
The porosity is reduced to about microns, and the porosity is 7.5%, 15%,
At 25%, chatter marks are no longer observed.

In this way, when the porosity of the chromium plating on the sliding surface of the rotor housing increases to more than about 5%, both the sliding surface roughness and the maximum amplitude of chatter marks decrease significantly, 7.5%, 15%.
% and 25%, no scuff marks or chatter marks were observed, and satisfactory results were obtained.

However, as the porosity increases, the plated surface becomes more prone to wear, and when the porosity exceeds approximately 40%, both the sliding surface roughness and the maximum amplitude of chatter marks increase, causing scratches, and long-term operation. This is not desirable as it may interfere with

Example 2 Avex seals and 1ox1oxss grooveless Charpy impact test specimens were manufactured from white cast iron having the chemical composition shown in Table 1 and in which free carbide was distributed at the area percentages listed. The rotary piston engine was fitted into a rotor housing having a chromium plating layer with a porosity of 25%, and the rotary piston engine was operated for 50 hours under the same conditions as in Example 1, and a 5 kg. m capacity Charpy impact test was conducted.

The test results are as shown in Figure 4, and when the area ratio of free carbide is 25%, there is a lot of wear, while when the area ratio is 75%, it becomes brittle and the impact value decreases. As mentioned above, the amount of carbide is 30-7
It turns out that it is better to set it in the range of 0%.

As explained above, the present invention has a rotor housing having a sliding surface coated with porous chrome plating with a porosity of 5 to 40%, and a structure in which free carbide with an area ratio of 30 to 70% is uniformly distributed. The rotating piston engine is characterized by a combination of a white cast iron Avex Seal, and the sliding surface of the rotor housing is porous, so it has excellent oil retention properties, and the Avex Seal that slides with the rotor housing has a porous sliding surface. Since free carbide is uniformly precipitated,
This combination is highly wear resistant, prevents scuffs and chatter marks, and has excellent properties that can withstand harsh use such as in rotary piston engines, significantly extending operating time. Can be done.

Carbides include not only cementite but also chromium,
It may be a double carbide containing tungsten or other alloying elements, or it may be a double carbide with these elements, but carbides mainly composed of cementite can be obtained at low cost, and post-treatments such as heat treatment and machining are relatively easy. It is.

[Brief explanation of drawings]

Figure 1 shows one of the Avex seal materials used in the present invention.
A photograph showing the microscopic structure of the example (400x magnification, 5% nitric acid alcohol solution corrosion), Figure 2 is a graph showing the relationship between the average porosity of the porous chromium plating layer of the rotor housing and the roughness of the sliding surface, Figure 3 Similarly, FIG. 4 is a graph showing the relationship between average porosity and chatter marks on the sliding surface, and FIG. 4 is a graph showing the relationship between free carbide area ratio, Avex seal wear amount, and Charpy impact value.

Claims (1)

[Claims] 1 Rotor housing with a sliding surface coated with porous chrome plating with a porosity of 5-40% and an area ratio of 30-40%
A rotary piston engine characterized in that it is combined with an avex seal made of white cast iron having a structure in which 70% free carbide is uniformly distributed.