JPH09203463A - Piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent concentration of stress of a top ring by arranging a plurality of groove parts along the inner side surface of the top ring fit to the piston circumferential surface of an internal combustion engine, and forming the depth of those groove parts deeper toward the vicinity of the fitting port part thereof. SOLUTION: A total of four groove parts consists of two groove parts 6 and two groove parts 6a are arranged on the inner side of a top ring 3 along the axial line of a piston. The depth of the recessed shaped groove parts 6, and the groove parts 6a are formed deeper toward the vicinity of the fitting port part 7 thereof. Stress concentration by fluttering of the different phase of the fitting port part 7 and stress concentration by twist of the top ring 3, which are troublesome in the case of enlargement of side clearance, are dispersed in a longitudinal direction of the top ring 3 by those recessed groove parts 6 and the groove parts 6a, and they are absorbed. A stress value applied on the top ring 3 is made in a constant level by deepening it on a position where stress is in a low level.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a piston ring fitted as a top ring of a piston used for sealing a combustion chamber of an internal combustion engine.

[0002]

2. Description of the Related Art Usually, a compression ring is provided in a ring groove provided on a peripheral surface of a piston 2 which reciprocates up and down in a cylinder liner 1 used in a combustion chamber of an internal combustion engine as shown in FIG. The top ring 3 and a plurality of rings such as an oil ring are fitted in multiple stages.

In particular, the top ring 3 receives pressure and high heat from the combustion chamber, and is exposed to extremely severe conditions such as carbon adhering to the lubricating oil and combustion gas. That is, the combustion pressure causes carbon to enter the gap between the top ring groove 4 and the top ring 3, and adheres and accumulates, eventually causing the top ring 3 to be fixed to the piston 2 and damaged.

In recent years, in order to increase the output of the internal combustion engine and cope with exhaust gas, a space indicated by D / V in FIG. 5 on the outer circumference of the piston 2 from the upper end of the top ring groove 4 to the upper end of the piston 2,
In other words, even if air enters, the size of the top land H tends to be reduced in order to reduce the dead volume, which is a space that is not used for combustion. Therefore, the top ring 3 and the top ring groove 4 become more difficult. It has become to.

As a countermeasure against this, an oil jet is introduced to cool the upper surface of the piston 2 and the top ring groove 4 is introduced.
A cooling channel 5 which is an oil passage for cooling the periphery is arranged along the peripheral surface of the piston 2, or a keystone ring having a wedge-shaped cross section is used to crush carbon by utilizing the wedge-shaped pressing force. It is conceivable to let it go out or further to increase the side clearance h which is the clearance between the top ring groove 4 and the top ring 3 so as not to cause sticking or the like immediately even if some carbon is deposited. ing.

However, the use of the cooling channel 5 and the keystone ring is costly. Further, it is preferable in terms of cost to increase the side clearance h, but if the side clearance h is increased, the following problems occur. That is, if the side clearance h is increased, flapping (fluttering) occurs in the top ring 3 due to fluctuations in combustion pressure and inertial force of the ring (high-speed sliding of the piston), and 180 degrees from the abutment portion of the top ring 3 Twisting around the position (portion on the opposite side of the diametrical direction of the abutment) causes stress to concentrate there, causing a problem of fatigue breakage in this vicinity.

[0007]

DISCLOSURE OF THE INVENTION The present invention prevents stress concentration at a position 180 degrees from the abutment portion of the top ring even when the side clearance between the top ring groove and the top ring of the piston of the internal combustion engine is increased. Another object of the present invention is to provide a piston ring capable of preventing fluttering due to different phases at the mating portion of the top ring and preventing stress concentration on the top ring.

[0008]

To achieve the above object, a piston ring according to the present invention is provided with a plurality of groove portions along an inner side surface of a top ring fitted to a piston peripheral surface of an internal combustion engine. The depth of the groove is formed so as to be closer to the mating portion of the top ring. And this groove is provided except for the diametrically opposite side of the abutment,
It is preferable to avoid the portion where stress is easily concentrated.

Further, in another type of piston ring of the present invention, the thickness of the top ring fitted to the peripheral surface of the piston of the internal combustion engine is formed so as to become thinner as the distance from the mating portion of the top ring increases.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A piston ring in each embodiment of the present invention will be described below with reference to the drawings. First, FIG.
2 is a plan view of FIG. 2 and an enlarged perspective view of an essential part thereof. A piston ring of one embodiment shown in FIG. 2 is a top fitted into a top ring groove 4 of a piston 2 of an internal combustion engine similar to the conventional example shown in FIG. The target is ring 3.

In this embodiment, a plurality of, for example, two groove portions 6, 6 are provided inside the top ring 3.
And a total of four groove portions consisting of two groove portions 6a, 6a are provided along the axis of the piston. Moreover, the depths of the concave groove portions 6 and 6a are formed so as to be closer to the mating portion 7 of the top ring. That is, in FIG.
The depth A of the groove 6 near the groove 6a and the groove 6a farther than the abutment 7
The depth B is such that A> B. With respect to the depths A and B, when the abutment portion 7 is opened, the maximum bending moment is generated on the opposite side of the abutment portion 7 in the diametrical direction.
And it is preferable to form the cross-sectional area of the groove portion 6 of the portion with a small moment to a size that matches the bending moment. However, in the actual top ring 3, it is related to the operating condition of the engine, so consider the experimental data. It will be decided while correcting.

By forming the groove portion 6 as described above, as described in the conventional example of FIG. 5, the side clearance h is taken as a measure for fixing the top ring 3 to the piston 2.
The stress concentration due to the out-of-phase fluttering of the abutment portion 7 and the stress concentration due to the twist of the top ring 3 due to the large side clearance h, which are problematic in the case of increasing the concave groove portion 6, 6a can disperse and absorb in the longitudinal direction of the top ring 3.

Further, the depth of the abutment portion 7 of these groove portions 6 is formed deeper and closer to the abutment portion 7, so that the stress value applied to the top ring 3 is made deeper at the low stress portion. It is possible to make it constant. That is, the top ring 3 of FIG. 1 can prevent breakage of the ring without increasing the width and height of the ring.

Next, a side view of the main part of the piston 2 of FIG.
An overall perspective view of the top ring of FIG. 4 shows a piston ring according to a second embodiment of the present invention. This top is also fitted into the top ring groove 4 of the piston 2 similar to the conventional example of FIG. The target is ring 3. The thickness of the top ring 3 of the piston 2 in this embodiment is set so that the thickness D at the position 180 degrees from the mating portion 7 is C> D with respect to the thickness C of the mating portion 7. There is. That is, the thickness C,
D is formed thinner as it goes away from the abutment 7.

The clearance between the top ring 3 and the top ring groove 4 at the mating portion 7 of the top ring 3 shown in FIG. 3 should be set so that the top ring 3 does not stick to the top ring groove 4. , The top ring 3 is shown in FIG.
As shown by arrow T, the upper and lower surfaces may be tapered, but the thicknesses C and D may be changed by tapering one surface. In the top ring 3 of this embodiment, the side clearance h at the abutment portion 7 is made as small as possible, and as the distance from the abutment portion 7 is increased, the thickness of the top ring 3 is made thin and the side clearance h is widened. In other words, while preventing carbon from sticking when entering between the top ring groove 4 and the top ring 3, it is possible to prevent out-of-phase fluttering at the abutment portion 7 and prevent stress concentration.

[0016]

According to the invention of claim 1, when the piston ring is applied to the top ring 3 in particular, the abutment portions 7 to 1
It is possible to prevent stress concentration at a position of 80 degrees. By making the depths of the plurality of grooves 6, 6a deeper toward the mating portion 7, it is possible to provide the piston ring 3 that has excellent rigidity balance and is lightweight.

According to the third aspect of the present invention, the side clearance at the abutment portion 7 is made as small as possible, and the thickness of the ring 3 is set to be thinner as the distance from the abutment portion 7 is increased, thereby preventing sticking. On the other hand, out-of-phase fluttering at the abutment portion 7 is prevented, and stress concentration can be prevented.
As a result, fatigue breakage of the top ring 3 can be reduced, and the reliability of the internal combustion engine can be improved.

From the above invention, there is provided a piston ring which does not cause a big problem even if the side clearance is increased as a measure for preventing sticking due to carbon deposition under high heat near the top ring 3 and the top ring groove 4 of the piston 2. Can be provided.

[Brief description of drawings]

FIG. 1 is a plan view of a top ring according to a first embodiment of the present invention.

2 is a perspective view showing a groove formed in the top ring of FIG. 1. FIG.

FIG. 3 is a side view of a main part of a piston fitted with a top ring according to a second embodiment of the present invention.

FIG. 4 is a perspective view of the top ring of FIG.

FIG. 5 is a side sectional view of a main part of a conventional piston upper part.

[Explanation of symbols]

2 Piston 3 Top ring 6, 6a Groove 7 Abutment A Depth B Depth C Thickness D Thickness

Claims (3)

[Claims] 1. A piston in which a plurality of groove portions are provided along an inner surface of a top ring fitted to a peripheral surface of a piston of an internal combustion engine, and the depth of these groove portions is formed so as to be closer to a mating portion of the top ring. ring. 2. The piston ring according to claim 1, wherein the groove portion is provided excluding the diametrically opposite side of the mating portion. 3. A piston ring in which the thickness of a top ring fitted to a peripheral surface of a piston of an internal combustion engine is formed so as to become farther from a mating portion of the top ring.