JPH0544842A - Manufacture of piston ring - Google Patents

Abstract

PURPOSE:To increase the thickness of a wear-resisting surface treated layer of the outer peripheral surface of a piston ring and to elongate the engine open interval by forming wedge-shaped slant surfaces on the upper and lower surfaces of a ring, plating the same, and then cutting off a portion corresponding to the height of the slant surface. CONSTITUTION:A wedge-shaped slant surface 7 with an angle A taking the contact surface between upper and lower surfaces of a piston ring 1 as the center is formed, and chamfering R1 is applied between the slant surface and the outer peripheral surface 12. The piston rings 1 are laminated, and a hard chrome plating layer 5, for example, is formed as a surface treated layer. The piston rings 1 are separated from a jig, and portions of the separated piston rings 1 corresponding to the height (t) of the slant surface 7 of the upper and lower surfaces thereof are eliminated by grinding. Thus, the thickness of the surface treat layer can be increased, the engine open interval can be elongated, the running cost can be lowered, sealing function of the ring can be improved, and the fuel consumption rate can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a piston ring suitable for providing a thick abrasion-resistant surface treatment layer on its outer peripheral surface.

[0002]

2. Description of the Related Art An outer peripheral surface of a piston ring for a large internal combustion engine having a relatively large diameter cylinder is provided with a surface treatment layer such as hard chrome plating for the purpose of abrasion resistance.

When the piston ring is coated with a surface treatment layer such as chromium plating, as shown in FIG. 2, a plurality of piston rings 1 are laminated to form a shaft 2 which also serves as an electrode rod.
Through the center of the piston ring 1 and presser plate 3 and nut 4
The piston ring 1 is fixed to the shaft 2 in a laminated manner by using.

Piston ring 1 laminated as shown in FIG.
Is placed in a plating tank and the shaft 2 is energized to form a surface treatment layer such as hard chrome plating on the outer peripheral surface of the piston ring 1. As shown in FIG. 3, the upper and lower corners of the outer peripheral surface of the piston ring 1 prevent local abnormal electrodeposition of plating that occurs due to the phenomenon of tip discharge of electric current, and prevent the plating from adhering to each ring in a connecting manner (plating crossover phenomenon). A chamfered portion 10 of R ₂ is provided to prevent this.

The plating layer 5 of the laminated piston ring 1 fixed to the shaft 2 has a mutual contact portion 6 of the chamfered portion 10 of R _2.
The change gradually becomes thinner toward the contact portion 6 and no plating transition phenomenon is observed at the contact portion 6. The thickness of the plating layer 5 in this case is 0.3
It is up to 0.5 mm (an example of a ring with an outer diameter of 700 mm, a width of 18 mm, and a thickness of 23 mm).

In the example shown in FIG. 4, the plating layer 5 has a thickness of 0.8.
In the example of millimeters, the plating layer 5
If the thickness is increased, a phenomenon of plating migration is observed in the chamfered portion 10. For this reason, the rings are not separated even after the jig is disassembled, and separation by impact with a plastic hammer is required. As shown in FIG. 5, such forced separation causes saw-tooth-shaped plating nicks 9 to continuously occur in the plating transition portion, so that it is impossible to manufacture a piston ring having a thick plating layer.

[0007]

Recently, as a measure for extending the engine opening interval, it has been desired to provide a piston ring having a thick surface treatment layer such as a hard chromium plating layer for the purpose of abrasion resistance.

[0008] Therefore, it is an object of the present invention to develop a method which enables the production of piston rings which meet the aforementioned needs.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention basically forms a wedge-shaped slope on the upper and lower surfaces of a piston ring, forms a plating layer, and then forms a sloped surface. A means for deleting the portion corresponding to the height is adopted.

More specifically, according to the present invention, a plurality of piston rings are laminated, a wedge-shaped space inward in the radial direction is provided on a boundary surface of the laminated rings which face each other, and a wear resistant surface is provided on an outer peripheral surface of the piston ring. Provided is a method for manufacturing a piston ring, which comprises electrodepositing a treatment layer, delaminating a piston ring, and removing a height corresponding to a slope forming a wedge-shaped space.

According to the present invention, the upper and lower surfaces of the piston ring are formed with wide slopes on the outer peripheral surface side, the piston rings are laminated, and a plating layer is formed on the outer peripheral surface of the piston ring. Provided is a method for manufacturing a piston ring, which comprises mechanically removing the height equivalent to a slope portion.

[0012]

According to the method of the present invention, each piston ring can be separated without the phenomenon of plating migration. The partial removal of the upper and lower surfaces of the piston ring increases the contact area between the ring groove surface and the upper and lower surfaces of the piston ring, and improves the airtightness of the ring. Further, the contact surface pressure is reduced and wear on the ring and the ring groove surface is reduced.

[0013]

[Example] Nominal outer diameter 700 mm, width 18 mm, thickness 23 mm,
A cast iron material corresponding to JIS B 8032 type 2 piston ring was laminated as shown in FIG. 2 and plated with hard chrome according to a conventional method. Each ring to be plated has a shape as shown in FIG.

That is, a wedge-shaped inclined surface 7 having an angle A of 30 degrees centering on the contact surfaces of the upper and lower surfaces of the piston ring 1 is formed.
And chamfer 3 mm between the inclined surface 7 and the outer peripheral surface 12.
Give ₁ . The thickness of the hard chrome plating layer 5 was 1.5 mm. As shown in the figure, there is no plating migration phenomenon, and the piston ring 1 can be easily separated from the jig.

0.2 mm corresponding to the height t of the inclined surface 7 on the upper and lower surfaces of the separated piston ring 1 was ground and removed. It was possible to extend the engine opening interval of the piston ring thus formed, reduce the running cost, improve the sealing function, and reduce the fuel consumption rate.

In the above-mentioned example, each piston ring 1 is previously prepared.
Although the sloped surface 7 is formed in and the wedge-shaped space is formed by stacking the sloped surface 7, the wedge-shaped sloped surface 7 may be formed after the piston ring 1 is stacked. Even if such a ring is laminated and plated, the same effect as the above-mentioned example can be obtained.

[0017]

According to the present invention, the surface treatment layer can be thickened only by forming a wedge-shaped slope on the upper and lower surfaces of the ring and performing the plating treatment and then grinding the portion corresponding to the height of the slope. Therefore, the engine opening interval can be extended, the running cost can be reduced, the ring sealing function can be improved, and the fuel consumption rate can be increased.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a piston ring used in an example method of the present invention.

FIG. 2 is a front view showing a state in which a piston ring is set on a jig.

FIG. 3 is a partial cross-sectional view of a practically used conventional piston ring.

FIG. 4 is a partial cross-sectional view of a conventional piston ring that cannot be used.

FIG. 5 is a perspective view showing a stripped portion of plating seen in a conventional example.

[Explanation of symbols]

 1 Piston ring 5 Plating layer 7 Slope 8 Chamfer 12 Ring outer surface A Wedge slope t Grinding amount

Continued Front Page (72) Inventor Masahiko Okabe 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries Ltd. Kobe Shipyard

Claims (3)

[Claims] 1. Stacking a plurality of piston rings,
A wedge-shaped space facing radially inward is provided on the boundary surface of the laminated rings that are in close contact with each other, a wear-resistant surface treatment layer is electrodeposited on the outer peripheral surface of the piston ring, delamination of the piston ring is unwound, and a wedge-shaped space is formed. A method for manufacturing a piston ring, which comprises removing the height equivalent to the slope. 2. Forming a wide slope on the outer peripheral surface side on the upper and lower surfaces of the piston ring, stacking the piston rings, forming a plating layer on the outer peripheral surface of the piston ring, and forming the slope portion. A method of manufacturing a piston ring, which comprises mechanically removing the height equivalent to the height of. 3. The method for producing a piston ring according to claim 1, wherein the intersection of the outer peripheral surface of the piston ring and the slope is chamfered.