JPS6345504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston ring for an internal combustion engine and a method for manufacturing the same. Recently, from the viewpoint of improving the fuel consumption efficiency of internal combustion engines and preventing exhaust gas pollution, it has been desired to further improve the airtightness around the cylinders of internal combustion engines.

90% of compressed gas leaks from the compression chamber of internal combustion engines
The above leakage is said to occur from the gap between the parts consisting of the piston and the piston ring, and it is said that the largest leakage is particularly from the gap between the piston rings. Therefore, in order to improve the airtightness of an internal combustion engine, it is necessary to improve the airtightness of the piston rings used, especially the joints of compression piston rings. By the way, as a piston ring for preventing fluid leakage from the abutment part of the piston ring, as shown in FIGS. A protrusion 5 protruding in the circumferential direction is provided, and a recess 7 for receiving the protrusion 5 is provided in the other abutment end 6 at a position corresponding to the protrusion 5, so that when the abutment is closed and installed, A so-called double angle structure in which the protrusion 5 is received in the recess 7 and the ends 8 and 9 of the circumferential contact surfaces extend circumferentially and are located on the ring outer circumferential sliding surface 3 and one side 4, respectively. Piston rings with a joint structure have been proposed and are used for some special purposes.

When the abutment part of the piston ring is configured as described above, a good sealing effect can be obtained because the flow path of the fluid flowing into the abutment part from the high pressure side is blocked by the presence of the protrusion 5. .

Therefore, if a piston ring having this type of joint structure can be used as a piston ring for an internal combustion engine, it can be expected that the airtightness of the internal combustion engine will be improved.

However, piston rings for internal combustion engines, especially upper-stage compression piston rings, are used under extremely severe operating conditions, so their outer sliding surfaces require a wear-resistant surface treatment layer such as chrome plating. However, in the piston ring having the abutment structure, since the protruding part 5 of the abutment end and the contact surface part 8 of the recess 7 appear in the circumferential direction on the outer peripheral sliding surface,
For example, when applying chrome plating treatment, in order to avoid build-up of the edge portion due to the plating treatment and to prevent the contact portion 8 between the protruding portion and the recessed portion from being bridged by the plating layer, as shown in Figs. 3 and 4, , it is necessary to chamfer each edge portion 10, and this chamfer forms a gas leakage path, making it impossible to obtain the desired airtightness.

Therefore, piston rings having this type of joint structure are not effectively used for internal combustion engines. In view of the above, the present invention has been made for the purpose of providing a piston ring for an internal combustion engine that has both good sealing properties and wear resistance properties. A protrusion protruding in the circumferential direction is provided at the corner of the frame, and a concave portion is provided at a position corresponding to the protrusion at the other end of the abutment to receive the protrusion in the attached state, and the outer circumferential surface is provided with a chrome plated part. A piston ring for an internal combustion engine, which has a double angle abutment structure having a roughening treatment layer, wherein the edge of the contact surface between the protrusion and the recess located on the outer peripheral surface of the ring is not chamfered. It concerns the manufacturing method.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In FIG. 1, one abutment end 2 of the piston ring is provided with a protrusion 5 that protrudes in the circumferential direction at a corner near the outer peripheral surface 3 and one side 4, and the other abutment end 6 is provided with a protrusion 5 that protrudes in the circumferential direction. A recess 7 that receives the protrusion 5 as shown in the figure when mounted at a position facing the protrusion 5.
will be established.

As shown in FIG. 7, the piston ring formed as described above is placed between the contact surfaces of the protruding portion 5 and the recessed portion 7 with an electrically insulating thin plate made of, for example, tetrafluoroethylene resin.
1 is slightly protruded from the outer circumferential surface 3 and the abutment is closed, and the outer circumferential surface 3 is subjected to chrome plating treatment, and the outer circumferential sliding surface is coated with a chrome plating layer 12.
form.

After forming the chromium plating layer, the thin plate 11 is removed, and if necessary, the outer peripheral surface is finished to complete the piston ring.

When forming a chromium plating layer on the outer circumferential surface as described above, the contact surfaces of the protrusion and the recess at the end of the abutment are separated by the electrically insulating thin plate 11, and the thin plate is attached to the outer circumferential surface of the ring. Because it is provided with a slight protrusion, the edge of the opposing surface between the protrusion and the recess can be bridged during the chrome plating process without chamfering the edge of the opposing surface. No layers are formed. Therefore, as shown in FIGS. 5 and 6, the piston ring obtained in this manner has good airtightness, with no gas leakage path formed at the edge of the contact surface between the protrusion and the recess. It exhibits excellent wear resistance and exhibits remarkable effects when used as a compression piston ring for internal combustion engines.

As described above, the present invention improves the wear resistance properties of a piston ring having a double-angle joint structure without impairing its good airtightness properties, thereby making it possible to use the piston ring as a piston ring for an internal combustion engine. The present invention provides piston rings that are effective in improving the performance of internal combustion engines and preventing exhaust pollution.

[Brief explanation of the drawing]

1 and 2 show a piston ring having a double angle abutment structure, FIG. 1 is a perspective view of the abutment part, and FIG. 2 is a sectional view taken along the line -- in FIG. 1. Figures 3 and 4 show a conventional piston ring with a double-angle abutment structure having a chrome plating layer; Figure 3 is a perspective view of the abutment;
- Line sectional view of the figure. 5 and 6 show the joint portion of the piston ring according to the present invention, and FIG. 6 is a sectional view taken along the line -- in FIG. 5. FIG. 7 is an explanatory diagram showing a method of manufacturing a piston ring of the present invention. In the diagram: 1... Piston ring, 2... One end of the joint, 3... Outer circumferential surface of the piston ring, 4...
Side surface of the piston ring, 5...Protrusion of the abutment part of the piston ring, 6...Abutment end, 7...Recess provided in the abutment end, 8...Abutment surface between the protrusion and the recess. Edge, 10... Chamfered portion, 11... Electrically insulating thin plate, 12... Chrome plating layer.

Claims (1)

[Claims] 1. A protrusion protruding in the circumferential direction is provided on the outer circumferential surface of one abutment end and a corner portion closer to one side, and
The piston ring has an abutment structure in which the other abutment end is provided with a recess for receiving the protrusion in a mounted state, and has a plating layer on the outer circumferential surface, the piston ring having a plating layer on the outer circumference of the ring. A piston ring for an internal combustion engine, characterized in that an edge of a contact surface between a protrusion and a recess is not chamfered. 2 A protrusion projecting in the circumferential direction is provided on the outer circumferential surface of one abutment end and a corner near one side, and the protrusion is installed in a position corresponding to the protrusion on the other abutment end. A thin plate made of an electrically insulating material is interposed between the circumferential contact surfaces of the protrusion and the concave portion of the piston ring material provided with a recessed portion for receiving the piston ring material, with the plate slightly protruding from the outer peripheral surface of the ring. 1. A method for producing a piston ring for an internal combustion engine, comprising: closing the piston ring, plating the outer circumferential surface, removing the thin plate, and then subjecting the outer circumference to finishing treatment.