JPS62121831A - Manufacture of rotor housing for rotary piston engine - Google Patents

Abstract

PURPOSE:To achieve the prevention of the occurrence of scratching abrasion in apex seals by forming numerous oil retaining recesses on the trochoid surface of a rotor housing by a the photo-etching method, and making soft members adhere to the opened peripheral edges of these recesses. CONSTITUTION:On the trochoid surface 1a of a rotor housing 1, numerous dispersed oil retaining recesses 14 having an approximately U-shape in cress- section are formed by the photo-etching method. Next, soft members S are made to adhere to the opened peripheral edges of oil retaining recesses 14 in such a way that the soft members S being soft metals of Sn, Zn, Pb, or the like, or the mixture of these metals and solid lubricants such as graphite or the like are pressedly brought into contact and slidably moved in the same direction as the sliding direction of an apex seal 6 using a honing-like tool. Thus, the occurrence of scratching abrasion in apex seals is prevented so as to enhance the initial conformableness, and from the long-range point of view abrasion resistance also can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a rotor housing for a rotary piston engine, which improves the initial conformability of a trochoidal surface.

(Prior Art) Generally, in a rotary piston engine, a polygonal rotor rotates planetarily inside a rotor housing whose inner circumferential surface is formed in a trochoid shape while an apex seal attached to the top of the rotor is in sliding contact with the trochoid surface. It is something to do. Conventionally, a large number of oil holding recesses each having a substantially U-shaped cross section are formed on the trochoidal surface of the rotor housing by photoetching, and the opening depth of the oil holding recesses is increased by adjusting the photoetching process conditions. The rotor housing has an increased oil retention capacity, and its U-shaped cross-sectional shape reduces the reduction in the opening area of the oil retention recess due to wear of the trochoid surface, and the oil retention recesses are regularly carved on the trochoid surface without variation. A manufacturing method has been proposed (Japanese Patent Application Laid-Open No. 60-3
(See Publication No. 431).

However, according to the conventional rotor housing manufacturing method described above, edges are formed at the opening edges of the oil holding recesses, so when the apex seal slides on the trochoidal surface, the edges cause scratching and wear, causing initial break-in. There was a drawback that this resulted in a decrease in wear resistance even in the long term.

(Object of the invention) ゛The present invention has been made in view of the above-mentioned conventional problems,
Among the edges of the opening edge of the oil holding recess.

Manufacture of a rotor housing that prevents scratching and wear of the apex seal by attaching a soft member to the advancing side of the sliding force of the apex seal, thereby improving initial conformability and long-term wear resistance. The purpose is to provide a method.

(Structure of the Invention) In order to achieve the above object, a method for manufacturing a rotor housing for a rotary piston engine according to the present invention includes a method of manufacturing a rotor housing for a rotary piston engine by forming a large number of oil retaining recesses each having a substantially U-shaped cross section, which are dispersed on the trochoidal surface of the rotor housing by a photoetching method. and then sliding the soft member against the trochoid surface in the same direction as the sliding direction of the apex seal to attach the soft member to the edge of the opening edge of the oil holding recess. There is.

With this manufacturing method, the soft member is attached to the edge of the opening edge of the oil retaining recess, which has a substantially U-shaped cross section and is provided on the trochoid surface, on the advancing side of the apex seal in the direction of the sliding force.

(Example) First, a rotor housing of a rotary piston engine manufactured by the method of the present invention will be outlined.

In FIGS. 1 and 2, A is a rotary piston engine, which includes a rotor housing 1 having a trochoidal inner circumferential surface 1a on which a chrome plating layer is formed, and side housings arranged on both sides of the rotor housing 1 and integrally fixed thereto. 2,2
A polygonal rotor 4 is installed inside the casing 3 consisting of
rotates planetarily, and the rotation of the rotor 4 causes the three working chambers 5, 5.5 defined within the casing 3 to sequentially perform the intake, compression, explosion, expansion, and exhaust strokes. Each top of the rotor 4 has the trochoidal surface 1
Apex seal 6 that keeps the working chamber 5 airtight by sliding in contact with a
is installed. Note that 7 is an eccentric shaft that supports the rotor 4, and 8 is a side seal that is attached to the side surface of the rotor 4 and slides on the side housing 2 to keep the working chamber 5 airtight. Further, 9 is a corner seal provided on both sides of the top of the rotor 4, 10 and 11 are trailing side and leading side spark plugs, 12 is an intake boat, and 13 is an exhaust boat.

The trochoid surface 1a of the rotor housing 1 has a third
Mutually independent oil holding recesses 1 having a substantially U-shaped cross-sectional shape and a circular opening shape as shown in FIGS.
4... are engraved over the entire surface of the trochoid surface 18 at equal pitch intervals in the vertical and horizontal directions. Further, the plateau portions 15 between the respective recesses 14 are formed to have a surface roughness of 1 μm or less.

Among the edges 16 of the opening edge of the oil holding recess 14,
On the advancing side of the sliding force direction of the apex seal 6 (indicated by the two-dot chain arrow in FIG. 3), there is Sn.

Soft metals such as Zn and Pb or these metals and graphite, boron nitride (BN), M.

A soft member S, which is a mixture of solid lubricant such as No. 82, is attached.

Next, the present invention for manufacturing such a rotor housing 1 will be explained in detail.

First, a hard chrome plating layer is formed on the surface of the base material (for example, steel) of the rotor housing 1, and then the surface of the chrome plating layer (trochoidal surface 1a) is polished to a surface roughness of 1 μm or less. On the other hand, in parallel with the above-mentioned work, an enlarged original drawing of the four oil holding parts 14 is prepared, and this is reduced by photographing and arranged on a sheet as a non-transparent part at a predetermined pitch in the vertical and horizontal directions. Fabricate a photomask.

Next, an ultraviolet-sensitive film photoresist (to be referred to as an edible resist) is applied to the trochoid surface 1a that has been cleaned with an organic solvent using a film application roll, and the photomask is placed on the film in close contact with the photoresist. In this state, the surface of the photomask is exposed to ultraviolet rays to photosensitively harden the film portions corresponding to the transparent parts (corresponding to areas other than the oil holding recesses 14). Then, the photomask is removed and the film is developed to dissolve and remove the uncured portion (unexposed portion), thereby forming a mask I7 as shown in FIG. 5 on the trochoid surface 1a. Next, this trochoid surface 1a is etched, and the parts not covered by the mask 17 (corresponding to the oil holding recesses 14) are corroded to form the oil holding recesses 14. engraved and then remove the mask. Naturally, during etching,
The part covered by the mask (the part formed on the plate part 15 after the work) is not cut and corroded and is left as a mirror surface with a surface roughness of 1 μm or less. In addition, in the above photoetching method,
Although a UV-sensitive film photoresist was used,
A photoresist film may be formed by applying a photoresist to the trochoid surface 1a and drying and hardening the photoresist.

After the above photoetching process is completed, a horn-shaped tool 19 (see Fig. 6) equipped with a block 18 made of a soft material is used instead of a grindstone, and the block 18 is trochoidally processed in the same manner as honing. Slide it into pressure contact with the surface 1a. At this time, when the sliding direction of the block 18 is made to match the sliding direction of the apex seal 6, as shown in FIGS. 3 and 4, the apex seal 6 A soft member S is attached to the advancing side of the sliding force direction.

Therefore, when the apex seal 6 slides on the trochoidal surface 1a, the scratching wear caused by the edges 16 is prevented, and the initial conformability is improved, as well as long-term wear resistance.

Furthermore, the soft member S attached to the edge 16 is also attached to the apex seal 6 by sliding of the apex seal 6 and is also stretched to the platelet part 15, so that the sliding characteristics in the platelet part 15 are improved. Initial conformability becomes even better.

Hereinafter, specific examples will be described in more detail.

The inventor of this application has a shape shown in FIG. 7, and the dimensions are φ=200.
A cast iron disk 20 of mm, t = 15+a was manufactured, and one surface 21 of the disk 20 was treated as shown in Table 1 below, and each was used as a test piece A.

B, C, D, and E.

Table 1 That is, specimens A, B, and C were treated according to the method of the present invention, and specimens E were treated according to the conventional method.

Here, chrome plating specifically refers to forming a hard chrome plating layer that satisfies the conditions shown in Table 2 below.

Table 2 Photoetching specifically refers to halftone type etching performed under the conditions shown in Table 3 below.

Note that the area ratio is the ratio of the total opening area to the total area of the mask 17 expressed as a percentage.

Table 3 In addition, Sn, Pb, and Zn shown in Table 1 above are obtained by preparing a block 18 made of such metals and applying two layers to the surface 21.
Refers to the adhesion treatment of each soft member by sliding it under pressure so that a load of kg/enf is applied. Specifically, each block 18 has a shape as shown in FIG. 8 and FIG. 9, with Q1 = 6 m, Q'2 = 90 mm, and Q
3 = 22mm and H1 = 5mm. Note that 18a is a sliding surface.

Next, the inventor used a pin-on-disk type abrasion tester 22 as shown in Fig. 1O to achieve a condition in which the apex seal slides on the trochoid hall of the rotor housing, thereby improving initial conformability and wear resistance. Gender was evaluated. That is, the disk 20 was rotated at high speed while the pin 23 was pressed against the surface 21, and the amount of wear on the pin 23 (height wear) and the degree of damage (scratches) on the surface 21 were examined. The test conditions are as shown in Table 4 below.

Table 4 The pin 23 has the shape shown in FIGS. 11 and 12, and 23a is the sliding surface. The dimensions are Q4 = 3m
m, Q5 = 10mm + ffa = 8mm,
H2=2mm. The pin 23 is made of chilled alloy cast iron, and its chemical composition is as shown in Table 5 below.

Table 5 The results of the above test were as shown in Table 6 below.

Table 6 Here, in the "Judgment" column, the overall test results, including initial conformability, are listed.

From Table 6 above, it can be seen that in the test pieces treated according to the method of the present invention, the amount of wear on the pins was reduced to 30% or less of that in the conventional case, and the damage to the test pieces themselves was extremely small.

Next, the inventor conducted a test in an actual rotary piston engine to compare the performance of the rotor housing manufacturing method according to the present invention and the conventional method.

That is, examples and conventional examples were those in which the surface of a base material made of an aluminum alloy (material: AC4D, treatment T6) was subjected to the treatments shown in Table 7 below. The contents of chrome plating, photoetching, and Sn are those of the above test piece A.
- Same as that applied to E.

Table 7 The rotary piston engine used in the test has a displacement of 1300 cc and is a turbocharged engine that generates a maximum output of 200 PS.

In this test, the engine speed was increased from 300 rpm to 700 rpm under full load with the accelerator fully open, this state was held for 40 seconds, and then the accelerator was released and the engine speed was lowered to 300 rpm.One cycle was 60 rpm.
00 cycles were performed, and the change in average effective pressure before and after the test and the amount of wear (height wear) of the apex seal were determined. The test results are shown in Table 8 below.

As shown in Table 8 above, in the Examples.

After the test, the average effective pressure was slightly improved, and this was due to improved sealing performance as a result of better initial conformability. Note that in the column describing the amount of wear of the apex seal in the conventional example, the fact that "uneven wear is large" means that the part of the apex seal that contacts the edges of the four oil retaining parts is noticeably uneven.

As described above, according to the method of the present invention, when the manufactured rotor housing is actually used in a rotary piston engine, the initial conformability is improved to the extent that it is confirmed that the sealing performance is extremely good, and the apex seal is improved. It can be seen that the amount of wear is also reduced to 1/10 or less of the conventional value.

The results shown in Table 8 above are consistent with the results in Table 6, and in both cases, the key point is to attach the soft member to the edge of the opening of the recess with a roughly U-shaped cross section formed by photoetching. This confirms the effectiveness of the method of the present invention.

(Effects of the Invention) As described above, the method for manufacturing a rotor housing for a rotary piston engine according to the present invention brings about the following excellent effects.

(1) In the rotor housing manufactured by the method of the present invention, the soft member is attached to the edge of the opening edge of the oil holding recess, which has a substantially U-shaped cross section, on the advancing side of the apex seal in the sliding direction. Even when the seal slides on the trochoidal surface, it prevents scratching and wear, improves initial conformability, and improves long-term wear resistance.

(n) The soft member attached to the edge is also stretched to a part of the plateau as the apex seal slides.
The sliding properties at a portion of the plate are improved, and the initial conformability becomes even better.

[Brief explanation of drawings]

1 to 5 show the rotor housing of a rotary piston engine manufactured by the method of the present invention, FIG. 1 is a longitudinal sectional view of the rotary piston engine, FIG. 2 is a perspective view of the rotor housing, and FIG. 3 is a Figure 4 is an enlarged sectional view showing the oil holding recess; Figure 5 is an enlarged view of the surface of the trochoid surface;
The figure shows the process of forming the oil retaining recesses by photoetching. FIG. 6 is a front view of the soft member adhesion treatment tool, FIG. 7 is a perspective view of a test piece, FIG. 8 is a front view of a block of soft members, and FIG. 9 is a side view of the same block.
Fig. 10 is a front view schematically showing a pin-on-disk type wear tester, Fig. 11 is a front view of the pin of the tester, and Fig. 12
The figure is a side view of the same pin. A...Rotary piston engine, 1...
... Rotor housing, 6 ... Apex seal, 14 ... Oil holding recess, 16 ...
・Edge, S...Soft member.

Claims (1)

[Claims] (1) Form a large number of dispersed oil retaining recesses with a roughly U-shaped cross section on the trochoidal surface of the rotor housing by photo-etching, and then insert a soft member into the trochoidal surface in the same direction as the sliding direction of the apex seal. A method of manufacturing a rotor housing for a rotary piston engine, characterized in that the soft member is attached to the edge of the opening of the oil retaining recess by sliding pressure.