JPH057526B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an apex seal of a rotary piston engine, and particularly to improvement of its sliding surface. (Prior art) Generally, in a rotary piston engine,
If the apex seal, which is made of alloy cast iron and has a sliding part that comes into sliding contact with the trochoidal surface of the rotor housing, has poor initial conformability, the sliding part (sliding surface) of the apex seal will generate abnormal heat, causing the upper and lower parts of the apex seal to The apex seal deforms into a convex shape due to the temperature difference, resulting in welding wear at the center of the apex seal, and conversely deforms into a concave shape at room temperature (when operation is stopped).
It is known that gas sealing performance is reduced and engine compression pressure is reduced. Therefore, conventionally, in order to improve initial conformability, soft metals such as tin, copper, and zinc were plated.
Methods such as roughening the surface by shot blasting or the like to provide oil retaining properties and to avoid complete contact are being used. However, these methods have a problem in that the hardness of the plated metal is low and the surface pressure during sliding is high, so that the rate of wear increases and the wrapping becomes ineffective after a short wrapping time. This is particularly a problem with high-output engines equipped with turbochargers, which have been increasingly adopted in recent years. Incidentally, as a prior art, there is Japanese Patent Publication No. 56-50081 in which a matte surface is formed by shot blasting on the sliding contact surface with the rotor housing. (Object of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to provide an apex seal for a rotary piston engine that has excellent initial conformability. (Structure of the Invention) The present invention relates to an improvement of an apex seal for a rotary piston engine, which is provided with a sliding portion that is chilled and comes into sliding contact with a toroidal surface of a rotor housing. In order to achieve the above-mentioned object, the present invention provides that the surface of the sliding part of the apex seal is roughened to form a large number of recesses, and that the surface of the sliding part of the apex seal is roughened and has a hardness of 500 to 900 Hv while leaving the large number of recesses. It is characterized by laminated electrolytic nickel alloy plating layers. Note that electroless nickel alloy plating may be made of electroless nickel composited with particles of graphite, molybdenum disulfide, boron nitride, PTFE, or the like. Here, if electroplating is used instead of electroless nickel alloy plating, it is difficult to leave the large number of recesses as they are due to poor throwing power, and there is a problem of poor adhesion. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. The rotary piston engine 1 shown in FIG. 1 has a casing 2 that is constructed by disposing side housings (not shown) on both sides of a rotor housing 3 whose inner peripheral surface is a trochoidal surface 3a. Inside the casing 2, a substantially triangular rotor 4 is supported by an eccentric shaft 5 and is configured to rotate planetarily in the direction of arrow A. Rotor 4
An apex seal 6 made of alloyed cast iron and having a sliding portion 6a that comes into sliding contact with the trochoidal surface 3a of the rotor housing 3 is attached to the top of each of the rotor housings. The rotor housing 3 also has an intake port 7.
and an exhaust port 8 are formed, and a trailing side spark plug 9 and a leading side spark plug 10 are respectively provided, while a side seal 11 is attached to the rotor 4. The above-mentioned apex seal 6 has a chilled surface (hardness) of the apex seal material 21 which has been chilled in order to have an oil retaining function and avoid full contact.
Hv700 to 900) is roughened by etching, shot blasting, etc. to form a large number of recesses 21a (see Fig. 2a), and then, the large number of recesses 21a remain (that is, a large number of recesses and recesses are formed). The electroless nickel alloy mesh layer 22, which has good compatibility with the trochoidal surface 3a of the rotor housing 3, is hard to cause seizure, and has excellent throwing power, is laminated without blocking the trochoidal surface 3a of the rotor housing 3 (see Fig. 2b).
(see). Next, a test conducted on the apex seal 6 will be explained. Test Method Using the apex seal 6 shown in FIG. 3, a wear test and a seizure test were conducted using a circumscribed swinging drum tester shown in FIG. 4. In addition,
In Figure 3, L ₁ = 56mm, L ₂ = 8.5mm, L ₃ = 2
mm, L ₄ = 3 mm, R ₁ = 2 mm, and P indicates the thermocouple mounting position. The Apex Seal 6 used in the test is shown in Table 1. In Example (M), self-lubricating composite plating was applied.

【table】

[Table] Furthermore, the chemical components of the examples of Apex Seal 6 are as shown in Table 2, unless otherwise specified in the notes of Table 1.

[Table] Furthermore, the surface finish of the sliding portion 6a of the apex seal 6 is as follows. Polishing finish Grinding wheel: GC# 60 (JIS) Abrasion: 1, 6a Shot blast finish Shot: Carborundum # 20 (silicon carbide) Abrasion: 10 to 40 Also, in the external oscillating drum tester 31, 32 is Cr plated 33 is a nozzle for dripping lubricating oil, 34 is a swinging member, and the apex seal 6 is attached to the surface of the rotating drum 32 by a spring 35 so that it is constantly pressed against it, and swings at an angle of . It's becoming like that. Therefore, set load: 18Kg/56mm length, drum outer diameter
176mm, lubricant: 10W-40, sliding speed 6.5m/
sec (710 rpm). Test Results The shape of the sliding surface of the apex seal 6 after the wear test is as shown in FIG. In addition, the amount of wear S
is as shown in Table 3 (see Example (a) in FIG. 5 for the amount of wear S). Therefore, Examples (h), (j), (k),
It can be seen that (l) has a small change in the shape of the sliding surface, a small amount of wear S, moderate wear, and good initial conformability. Note that the wear amount S is specifically as shown in Table 3.

【table】

[Table] On the other hand, the results of the seizure test are as shown in Figure 6, and in Examples (h), (j), (k), and (l) according to the present invention, other materials caused seizure. It can be seen that no burn-in occurs even after 60 minutes. (Effects of the Invention) Since the present invention is configured as described above, the initial conformability is improved due to the synergistic effect of the multi-recessed portions that promote wear and oil retention, and the electroless nickel alloy plating layer that has appropriate hardness. This improves seal seizing, abnormal wear, and decreases in compression pressure.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is an overall configuration diagram of a rotary piston engine;
Figures 2a and b are illustrations of the manufacturing method of Apex Seal, Figure 3 is an illustration of the Apex Seal sample, Figure 4 is an illustration of the test system, and Figures 5 and 6 are the test results. FIG. DESCRIPTION OF SYMBOLS 1... Rotary piston engine, 3... Rotor housing, 3a... Trochoid surface, 6... Apex seal, 6a... Sliding part, 22... Electroless nickel alloy plating layer.

Claims (1)

[Claims] 1. An apex seal for a rotary piston engine, which is provided with a sliding part that is chilled and comes into sliding contact with a trochoidal surface of a rotor housing, wherein the surface of the sliding part is roughened to form a large number of recesses, and the surface of the sliding part is roughened to form a large number of recesses. An apex seal for a rotary piston engine characterized by a laminated layer of electroless nickel alloy plating with a hardness of Hv500 to 900 while leaving a recessed part.