JPH04176897A - Plating treatment of rail ring for combined oil control ring made of steel - Google Patents

Abstract

PURPOSE:To make plating treatment of extremely thin rail rings without generating plating transition by disposing intermediate rings of the diameter smaller than the diameter of the multiple stacked rail rings between these rail rings. CONSTITUTION:The intermediate rings 12 which have the diameter slightly smaller than the outside diameter of the rail ring blank materials 11 of the oil control ring made of steel or the diameter slightly larger than the bore thereof and have the shape similar to the shape of the rail ring blank materials 11 are mounted to bar-shaped jigs for a plating treatment between the individual rings of the multiple stacked rail ring blank materials 11. Recessed parts are formed between the rail ring blank materials 1 in the outer peripheral parts in this case. Plating 14 sticks like mushrooms to the front ends of the outer periphery of the rail ring blank materials 11 if the rings are subjected to the plating treatment in this state. Since the plating does not stick to the intermediate rings 12, the plating transition between the adjacent rail ring blank materials 11 does not arise. The intermediate rings are reusable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention primarily relates to a method for plating a rail ring of a combination oil control ring made of steel for a small internal combustion engine. [Prior Art] Small internal combustion engines, such as four-stroke gasoline engines such as automobile engines, are aimed at higher output, smaller size and lighter weight, and are required to have shorter and smaller pistons.

Therefore, the vertical width dimension of the piston ring, which is a component of the piston, has also been forced to be reduced. Furthermore, reducing the width dimension is strongly desired as a measure to reduce the inertia of piston rings aimed at high rotation and high output.

Examples of reductions in ring width include compression rings from 1.2 mm to 1.2 mm; It has been reduced to Om. Also, the oil control ring has gone from 4 holes to 2.5mm, and even 2 sections.

These size reductions leave some challenges in terms of ring functionality and manufacturing, particularly in the case of prepared combination oil rings, the extremely thin rail ring width dimension is also a prerequisite for size reduction.

In the manufacturing process in which wear-resistant chrome plating is applied to the outer or inner circumference of rail rings, plating is continuously deposited between adjacent rings in the gaps where plating is performed with multiple rail rings stacked. A plating phenomenon may occur that makes it impossible to separate the rings individually.

Rail rings with reduced plating thickness to avoid this phenomenon have problems with durability.

[Problem to be solved by the invention]

An object of the present invention is to solve the above-mentioned conventional problems and provide a plating method that does not cause the plating build-up phenomenon even when a sufficient thickness of wear-resistant plating is applied to a rail ring with a small vertical width dimension. [Means for Solving the Problem] The present invention solves the above problem in a method for plating a rail ring of a steel combination oil control ring having a wear-resistant plating layer on at least one of the outer periphery and the inner periphery. ,
A shape similar to that of the rail ring, having a dimension that satisfies at least one of a diameter that is somewhat smaller than the outer diameter of the rail ring or a diameter that is somewhat larger than the inner diameter between the individual rail rings that are stacked multiple times. The problem was solved by a rail ring plating method characterized by arranging an intermediate ring and performing the plating process.

[Effect]

According to the present invention, a large number of rail rings to be plated are stacked with an intermediate ring interposed between them, and in this case, the outer diameter of the intermediate ring is smaller than the outer diameter of the rail ring, or the inner diameter of the intermediate ring is smaller than that of the rail ring. Since either the inner diameter is larger than the inner diameter, or both are satisfied, the intermediate ring portion is concave at one or both of the outer circumferential portion and the inner circumferential portion between the rail rings. Since it is plated in this state,
The part to which the plating is attached will be separated by the intermediate ring, and no plating will occur. Also, if a radiation-dissipating intermediate ring is used, the distance between adjacent rail rings will be extremely narrow, so the plating will not be applied to the surface of the intermediate ring. Not attached.

〔Example〕

The details of the present invention will be explained based on embodiments shown in the drawings.

In FIG. 1, a ring groove 3 is formed in a piston 2 that slides inside a cylinder, and a steel combination oil control ring 4 having a vertical width of two holes, for example, is fitted into the ring groove 3. , a combination oil control ring 4 made of steel includes a spacer expander 5 and an upper rail ring 6.
and a lower rail ring 7.

This steel combination oil control ring 4 has an upper and lower rail ring 6 with a vertical width of 0.3 sections and a radial thickness of 2.5 sections.
．． Chromium plating 8 with a film thickness of 0.0Elo or more is applied to the outer periphery of 7, that is, the portion in contact with the cylinder 1.

From a JIS spring steel type 5UP-3 copper strip, the outer diameter is 65 f.
A rail ring material 11 formed as a spiral coil ring of fIITl and an outer diameter 64 formed as a spiral coil ring similar to the rail ring with a vertical width of 025 sections and a radial thickness of 2 holes made of the same material as the rail ring.
The intermediate ring 12 of Peng is attached to a rod-shaped plating jig 13 as shown in FIGS. 2 and 3. In this case, a recess is formed between the rail rings 11 on the outer periphery.

Rail ring 11' and intermediate ring 1 of the same size and shape
For comparison, FIG. 5 shows a conventional product which was plated under the same conditions as the present invention, in which the plates 2' are arranged alternately in a spiral pattern and are mounted on a plating rod-shaped jig 13.

The rail ring attached to the rod-shaped plating jig 13 shown in FIGS. 2 and 5 was placed in an industrial plating solution bath composed of chromic acid, sulfuric acid, and sodium silicofluoride at a solution temperature of 57°C and a current density of Plating was performed for a predetermined period of time under the condition of 45 A/dm2.

As a result of the plating treatment, in the method of the present invention, as shown in FIG. Adjacent rail ring 1 through
No plating cross-over phenomenon occurs during this period. The plating thickness was approximately 0.01 mm (at the leading edge).

Since there was almost no plating on the outer periphery of [Intermediate Ring] 2, it was confirmed that the intermediate ring could be reused.

In the conventional products shown in section 5 and FIG. 6, as shown in section 7, the space between adjacent rings 11' and 12' is completely sealed by the plating 14, resulting in a plating gap and the post-plating Even after the jig 13 was dismantled, it was still impossible to separate the rail ring 11'.

In the plating test using the conventional method, the rail ring 11'
The separable plating thickness was approximately 0.03 mm, which was confirmed to be less than half of the required engine life.

〔effect〕

The present invention has made it possible to apply a plating film thickness equivalent to that of a conventional thick rail ring to an ultra-thin rail ring that is less than half the vertical width of a conventional rail ring.

It has become possible to provide a steel combination oil control ring with a combined width dimension of 2 or less and a rail ring that has a longer wear-resistant life than before.

With the present invention, the engine can be made compact and light without compromising its durability.
This made it possible to develop high-performance engines.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a copper combination oil control ring when it is attached to a piston, Fig. 2 is a front view of a rail ring attached to a rod-shaped plating jig according to the method of the present invention, and Fig. 3 is a sectional view of a copper combination oil control ring when it is attached to a piston. 2 is a partial enlarged view of FIG. 2, FIG. 4 is a view corresponding to FIG. 3 showing the state after plating, and FIGS. 5 to 7 are views corresponding to FIGS. 2 to 4 showing the conventional state. It is. 11.11'...Rail ring 12.12'...Intermediate ring 14...Plating layer agent Patent attorney Hideaki Kuwahara Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (4)

[Claims] (1) In a rail ring plating method for a steel combination oil control ring having a wear-resistant plating layer on at least one of the outer periphery and the inner periphery, the outer periphery of the rail ring is A rail characterized in that a plating treatment is performed by arranging an intermediate ring having a similar shape to the rail ring and having a dimension that satisfies at least one of a diameter that is somewhat smaller than the diameter or somewhat larger than the inner diameter. Ring plating method. (2) The rail ring and manufacturing method according to claim 1, characterized in that the rail ring and the intermediate ring are alternately stacked in a spiral pattern and then plated. (3) The method for plating a rail ring according to claim 1 or 2, wherein the top and bottom thickness dimensions of the rail ring are 0.35 mm or less. (4) The method for plating a rail ring according to any one of claims 1 to 3, wherein the outer peripheral plating thickness is 0.05 mm or more.