JPH0774464B2 - Sliding contact member - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding contact member having a sliding surface of another member, such as a rotor housing of a rotary piston engine,
In particular, the present invention relates to a slide member whose initial conformability with a sliding member and wear resistance are improved.

(Prior Art) It has been conventionally known that solid lubricants such as graphite and fluororesin are materials having a low friction coefficient and excellent initial conformability. However, when these materials are coated on the surface of the hard layer forming the sliding surface of the member, the adhesion with the sliding member is poor. Therefore, it has been proposed to coat the surface of the hard layer together with other thermal spray powder, and a powder obtained by adding nickel to graphite, a fluororesin or the like is coated on the hard layer. For example, JP-A-58-158251 discloses a rotor housing for a rotary piston engine having such a sliding surface. That is, in this publication, in order to improve the initial conformability between the trochoidal surface (sliding surface) of the rotor housing and the tip surface (sliding member) of the apex seal of the rotor, nickel plating in which fluororesin particles are dispersed is applied. It is applied to the trochoid surface.

(Problems to be Solved by the Invention) However, in the case where the sliding surface is nickel-plated as described above, although the initial conformability is improved,
Since nickel itself does not have good sliding characteristics, the amount of wear on the sliding member side and, in the case of the rotor housing, on the apex seal of the rotor increases, and the durability of such sliding member decreases. There was a problem.

The present invention has been made by paying attention to the problems of the prior art, and sliding while maintaining the initial conformability with the sliding member, and without impairing the wear resistance of the sliding member. An object is to provide a sliding contact member having a surface.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a sliding contact member which has a surface made of a hard layer and which is a sliding surface of another member. A composite layer of molybdenum in which at least one particle of graphite or fluororesin is dispersed is formed on the moving surface.

As shown in FIG. 1, in the sliding contact member of the present invention, the sliding surface 3a is formed by the hard layer 3b, and further, this hard layer
A molybdenum composite layer 3c in which solid lubricant particles 3d are dispersed is formed on 3b.

The above composite layer is obtained by mixing molybdenum and a solid lubricant in a predetermined amount, and mixing the mixed powder by a usual thermal spraying method.
It can be formed by coating on the hard layer to a predetermined thickness.

Here, as the solid lubricant, graphite and fluororesin (PT
FE etc.) is used. The mixed amount of the solid lubricant is not particularly limited, but the larger the mixed amount, the better the initial conformability. Usually, this mixing amount is 10 to 55% with respect to the mixed powder.

The thickness of the composite layer is not particularly limited, but is usually set to 10 to 30 μ. Further, as the thermal spraying method for forming this composite layer, an ordinary powder thermal spraying method can be used. Among them, the plasma thermal spraying method, in which the velocity of the thermal spray particles is high and the thermal effect on the base material is small, is particularly preferable. It is suitable.

The hard layer may be a known layer such as a plating layer, a thermal spray layer, or a gas soft layer. Further, the surface roughness of this hard layer, if it is rough, will improve the adhesion of molybdenum, but the amount of wear of the sliding member tends to increase. Therefore, Ra of 0.2 to 0.7 is usually preferable. .

(Effects of the Invention) As described above, in the sliding contact member of the present invention, since the composite layer of molybdenum in which solid lubricant particles are dispersed is formed on the sliding surface formed of the hard layer, the sliding member In addition to improving the initial conformability between and, the presence of molybdenum powder in this composite layer improves the sliding characteristics of the sliding surface,
The amount of wear of the sliding member is reduced and wear resistance is improved.

(Example) Below, the Example of this invention is described with reference to drawings.

FIG. 2 shows a rotor housing of a rotary piston engine to which the present invention is applied. As already known, a fuel injection type rotary piston engine 1
Has a rotor housing 3 having a trochoidal inner peripheral surface 3a, in which a triangular rotor 5 is eccentrically rotated. Apex seals 7 are attached to the tops of the rotors 5, and these apex seals 7 slide on the inner peripheral surface 3a of the housing 3 in an airtight state.
The rotor housing 3 is made of an aluminum alloy, and its inner peripheral surface 3a is composed of a hard layer 3b and a composite layer 3c formed on this surface, as shown in FIG. The composite layer 3c is composed of a layer of molybdenum in which particles 3d of solid lubricant are dispersed.

Using a rotary engine having a rotor housing having such a configuration and a rotary engine having a conventional configuration, initial conformability and wearability were evaluated under the conditions described below.

(Conditions) (1) Engine used: 1300CC (13B type) rotary engine, output 200PS (2) Inner peripheral surface of rotor housing (sliding surface): As shown in Table 1, from No. 1 to No. 8 8 types of layered rotor housings were manufactured, and these were assembled in an engine and tested. Of these, No. 8 does not contain a solid lubricant.

(3) Test mode: (a) Initial conformability The compression pressure PC of the engine working chamber was measured with the lapse of operating time of the rotary piston engine, and the initial conformability was evaluated from the drop rate. (The details of the PC down test will be described in (4).) (B) Wearability The wear amount of the apex seal after the above PC down test was evaluated.

(4) PC down test: In this test, the rotary piston engine was repeatedly operated according to the PC down evaluation mode as shown in FIG.
The pressure drop in the working chamber during that time is measured. That is, first, the engine was continuously operated at 1800 rpm for 18 minutes with no load, then continuously operated at 1200 rpm, MGS (tung oil and MoS ₂ ) was injected, and further, continuously operated at 1800 rpm for 18 minutes without load, and then PC was measured. This value was used as the reference value PCo. After that, after forced cooling for 1 hour, 1500 rpm
The basic mode in which the engine speed was raised and lowered 3 times with a full load every minute between 1 and 7,000 rpm was repeated. After repeating this 21 times, the compression pressure PC was measured. The decrease rate was calculated as the PC down rate from the standard value PCo of this value.

(Test Results) Table 1 shows the initial conformability and wearability in each case. As you can see from this table, the solid lubricant
In all of No. 1 to No. 4 having a content of 10 to 55%, the PC down rate was 10% or less and the wear amount was 1.0 μ or less. These values sufficiently satisfy the initial conformability and wear characteristics required for the inner peripheral surface of the rotor housing of the rotary piston engine.

On the other hand, in No. 5, the amount of solid lubricant added to molybdenum was large, so the initial conformability was improved by that much, but the amount of wear of the apex seal was large. Further, in Nos. 6 and 7, since the amount of the solid lubricant was small, the amount of wear was small, but the initial conformability was somewhat poor. On the other hand, in No. 8 in which the composite layer is not sprayed, the initial conformability is poor and the wear amount is small, which is unsuitable for the rotor housing of the rotary piston engine.

In addition, although the above-mentioned embodiment demonstrated the rotor housing of a rotary piston engine, this invention is not limited to the inner peripheral surface of this rotor housing. Of course, it can be applied to sliding surfaces of other members.

[Brief description of drawings]

FIG. 1 is a sectional view showing a layer structure of a sliding surface of the present invention, FIG. 2 is a sectional view showing a rotor housing of a rotary piston engine to which the present invention is applied, and FIG. 3 is an operating mode of the engine in a PC down test. FIG. 1 ... Rotary piston engine, 2 ... Rotor housing, 3a ... Inner peripheral surface (sliding surface), 3b ... Hard layer, 3c ... Compound layer, 3d ... Solid lubricant, 5 ... Rotor, 7 ...... Apex seal (sliding member).

Claims (1)

[Claims] 1. A sliding contact member having a surface made of a hard layer, the surface being a sliding surface of another member, wherein at least one particle of graphite or fluororesin is dispersed on the sliding surface. A sliding contact member, characterized in that a composite layer of molybdenum is formed.