JPH06235461A - Combined oil ring - Google Patents

Abstract

PURPOSE:To prevent increase of oil consumption as a side ring independently rotates. CONSTITUTION:On a side rail inner peripheral surface 3 of a combined oil ring constituted of two pieces of side rails 1 and a spacer expander 2 sandwiched by the side rails 1 and having a lug part 4 engaged with their inner peripheral surfaces, a soft metal plated layer of copper, copper alloy and the like of micro Vickers hardness 150-350, thickness 5-30mum is formed and to the spacer expander 2, nitriding is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine which comprises two side rails and a spacer expander which is sandwiched between the side rails and has ears for locking the inner peripheral surfaces of these side rails. A combination oil ring of an engine.

[0002]

2. Description of the Related Art As is well known, a piston that reciprocates in a cylinder of an internal combustion engine is fitted with an oil ring in addition to a pressure ring to scrape off lubricating oil from the wall surface of the cylinder and prevent it from burning. I am trying to do it.

As an oil ring, as shown in FIGS. 1 and 2, two side rails 1 and an ear portion 4 which is sandwiched between the side rails 1 and locks the inner peripheral surfaces 3 of the side rails.
Of the combination oil ring, which is formed by projecting from the inner peripheral portion on both sides in the axial direction and having the elasticity to expand outward in the radial direction, has a better spring characteristic than the conventional integrated oil ring. It is widely used because of its excellent followability to the inner surface of the cylinder.

In the illustrated example, the spacer expander 2 has a concavo-convex shape in the axial direction, is formed in a corrugated shape extending in the circumferential direction, and is fitted in the ring groove of the piston in combination with the pair of side rails 1. In this state, the spacer expander 2 generates an elastic force that tends to expand outward in the radial direction and an elastic force that increases the axial thickness, whereby the side rail 1 is attached to the side surface of the ring groove. Inner surface 3 while being pressed
Is pushed outward by the outer surface of the ear portion 4 of the spacer expander 2, and the outer peripheral surface of the side rail 1 is the inner surface 5 of the cylinder.
It will be pressed against and will slide.

As described above, in the combined oil ring, the inner peripheral surface 3 of the side rail and the outer surface of the ear portion 4 of the spacer expander 2 are strongly pressed against each other, so that the piston repeatedly reciprocates. On the inner surface 3 of the side rail 1
And the outer surface of the ear portion 4 of the spacer expander 2 rub against each other while being in pressure contact with each other.

Conventionally, the spacer expander and the side rails have been subjected to a nitriding treatment, and the inner peripheral surface of the side rails has a nitride layer excellent in wear resistance formed by the nitriding treatment, so that no abrasion occurs. However, even if they come into contact with the ears of the spacer expander and push them against each other by repeating the reciprocating motion of the piston, the cross section of the inner peripheral surface of the side rail is arcuate and the surface is hard, and therefore the ears of the spacer expander are eaten. As a result, the inner surface of the side rail and the spacer expander are not fixed to each other.
The independent rotation of the side rail will progress early.

When the side rail rotates independently, the sealing performance of the oil ring deteriorates, resulting in an increase in the amount of lubricating oil consumed, which is an undesirable effect.

As a countermeasure, for example, Japanese Patent Application No. 58-1
Japanese Patent No. 10180 discloses a method of forming a coating layer of a non-metallic material having a low coefficient of friction on the inner peripheral surface of the side rail of the combined oil ring or on the ears of the spacer expander. However, non-metallic materials with a low coefficient of friction, such as 4
The coating layer formed by coating with an organic resin such as ethylene fluoride (trade name: Teflon) is too soft, wears off at an early stage, does not bite, and rotates.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the conventional combined oil ring, and at the contact portion between the inner peripheral surface of the side rail and the ear portion of the spacer expander, the side rail of the side rail is extended for a long period of time. An object of the present invention is to provide a combined oil ring capable of preventing independent rotation.

[0010]

In order to solve the above-mentioned problems, the present invention provides a combination oil ring having the above-mentioned structure, which comprises two side rails and a spacer expander sandwiched between these side rails. Micro Vickers hardness 150-350, film thickness 5 on the inner surface of the side rail
A soft metal plating layer having a thickness of up to 30 μm is formed, and a nitriding layer is formed on the surface of the spacer expander.

[0011]

The micro Vickers hardness of the soft metal plating layer formed on the inner surface of the side rail is 150 to 350,
When the inner peripheral surface of the side rail is pressed against the ears of the spacer expander with the nitriding layer and the piston is reciprocated, the ears are made of a soft metal due to repeated pressing. It is a value suitable for biting into a layer and maintaining the biting state.

If the hardness of the inner peripheral surface of the side rail is such that tin or lead has a micro Vickers hardness of 150 or less, the side rail is immediately worn, and if the hardness is 350 or more, the bite does not progress and the relative position cannot be fixed. . Therefore, the hardness of the inner surface of the side rail is 150 to 3 micro Vickers hardness.
A range of 00 is suitable.

As a soft metal having this hardness range,
Copper, copper-tin, copper-zinc based copper alloy plating is suitable,
There is no problem with rust or corrosion in the engine.

As the thickness of the soft metal plating layer,
If it is 5 μm or less, the bite holding force is weak and there is no effect. Thirty
Since the thickness is 5 μm or less, it can be sufficiently fixed and maintained.
It is suitable to be in the range of ˜30 μm, more preferably 10 to 25 μm.

From the above, according to the present invention, the ear portion of the spacer expander in which the nitriding layer is applied to the inner peripheral surface of the side rail on which the soft metal plating layer having the micro Vickers hardness of 150 to 350 and the film thickness of 5 to 30 μm is applied. When the piston is reciprocated, the ears can appropriately bite into the inner peripheral surface of the side rail and maintain the biting state.
The relative position of the side rail and the spacer expander can be fixed.

[0016]

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings showing test results in comparison with comparative examples. Table 1 shows the treatment of the spacer expander surface and the side rail inner peripheral surface of each of the combined oil rings of the example of the present invention and the two comparative examples.

[0017]

[Table 1]

A combination oil ring obtained by combining a surface expander and a side rail shown in Table 1 was fitted on a piston and mounted on a cast iron cylinder.
A 100-hour bench test was performed to measure oil consumption. The operating conditions are as follows. 6500 rpm x 4/4 x 100 hr Oil temperature: 120-130 ° C Water temperature: approx. 90 ° C Oil: Dezerax, 10W-30 Engine: 83mmφ, 4 cycles, in-line 4 cylinder, water cooling Fuel: Unleaded gasoline

The test results are shown in FIG. In the figure, ◯ is the measured value for the example of the present invention, Δ and ● are comparative examples 1 and 2, respectively.
Is the measured value for. From this test result, the piston ring of the example of the present invention, compared with the comparative example in which the side rail that was only subjected to nitriding treatment, and the side rail that was subjected to chrome plating on it, It can be seen that the consumption is low. This is because the ear of the spacer expander bites into the copper-tin alloy plating layer of soft metal plating applied to the inner peripheral surface of the side rail,
This is the result of preventing the side rails from rotating independently. The amount of bite into the copper-tin alloy plating layer is 15 μm.
It can be seen that the depth of the ears is deeper and the ears are fixed as compared with 3 μm for chrome plating and 2 μm for the nitride layer. In addition, in the side rail of the comparative example, the mark that the side rail is rotated with respect to the spacer expander can be confirmed. It can be understood that the oil consumption increases because the side rail rotates independently if the amount of biting into the inner peripheral surface of the is small.

In the above description of the embodiments, a copper-tin alloy was given as an example of the soft metal, but copper, copper-zinc alloy and the like are also suitable metals.

[0021]

As described above, according to the present invention, the independent rotation of the side rails of the combined oil ring can be prevented for a long period of time, and the oil consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing a configuration of a combined oil ring to which the present invention is applied.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a curve diagram showing a comparison of oil consumption in actual machine tests of an example of the present invention and a comparative example.

[Explanation of symbols] 1 Side rail 2 Spacer expander 3 Side rail inner peripheral surface 4 Spacer expander ears 5 Inner surface of cylinder

Claims (1)

[Claims] 1. A pair of side rails and a spacer expander which is sandwiched between these side rails and has ears for locking the inner peripheral surfaces of these side rails so as to project axially on both sides of the inner peripheral portion, The outer surface of the ears of the spacer expander, when fitted together in the ring groove of the piston, pushes the inner peripheral surface of the side rail outward by the elasticity of the spacer expander itself, In the combined oil ring of the internal combustion engine, the outer peripheral surface of which is slidably pressed against the inner surface of the cylinder, the micro Vickers hardness 1 is applied to the inner peripheral surface of the side rail.
A combined oil ring, wherein a soft metal plating layer having a thickness of 50 to 350 and a film thickness of 5 to 30 μm is formed, and a nitriding layer is formed on the surface of the spacer expander.