JP3244396B2 - piston ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston ring used for a piston reciprocating in a cylinder.

[0002]

2. Description of the Related Art As a piston ring for a piston reciprocating in a cylinder, a piston ring in which a synthetic resin ring having a very low self-tension is pressed from the inside to the outside by an expander ring having a self-tension is known. See JP-A-57-148036).

[0003]

However, in the piston ring disclosed in the above publication, the gas compressed by the piston as the synthetic resin ring moves up and down in the ring groove,
The problem of leakage from the combustion chamber side through between the upper surface of the ring groove and the upper surface of the synthetic resin ring, between the ring groove and the back surface of the synthetic resin ring, and between the lower surface of the ring groove and the lower surface of the synthetic resin ring. There is.

[0004] In view of the above problems, an object of the present invention is to provide a piston ring using a synthetic resin ring that does not leak gas compressed by the piston.

[0005]

According to a first aspect of the present invention, there is provided a synthetic resin ring inserted into a ring groove formed in an outer peripheral surface of a piston, and the synthetic resin ring having a self-tension is provided from inside to outside. In the piston ring consisting of an expander ring that presses, an elastic ring having a vertical width equal to or greater than the vertical width of the piston of the ring groove is interposed between the synthetic resin ring and the expander ring, and A piston ring is provided, wherein the elastic ring includes the expander ring.

[0006]

According to the first aspect of the present invention, when the expander ring presses the elastic ring outward, the back surface of the synthetic resin ring comes into close contact with the elastic ring over the entire circumference.
The elastic ring adheres to the upper and lower surfaces of the ring groove by its own elasticity, and the gas compressed by the piston flows around the upper surface of the ring groove and the back surface of the synthetic resin ring from the gap between the synthetic resin ring. To prevent leakage through the gap between the lower surface of the ring groove and the synthetic resin ring. When the expander ring is included in the elastic ring, the integrated expander ring and elastic ring are assembled when assembled to the piston.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a first embodiment of the present invention applied to a piston ring of an internal combustion engine. In FIG. 1, reference numeral 1 denotes a piston, and 2 denotes a ring groove formed in the piston 1. . 3 is a synthetic resin ring, for example,
It is made of tetrafluoroethylene, has no circumferential cuts, and itself has very low tension. 4a
Is an elastic ring made of, for example, heat-resistant rubber. Reference numeral 5 denotes an expander ring, which is made of, for example, a metal such as steel, has self-tension, and presses the synthetic resin ring 3 toward the outside in the radial direction of the piston 1 via an elastic ring 4a to form a composite. The resin ring 3 is in contact with the cylinder liner 6 via oil (not shown).

In the first embodiment, the elastic ring is 4a.
As shown in the figure, it has a hollow pipe shape, and the expander ring 5 is included therein.

Since the diameter of the cross section in the free state is larger than the width D1 of the ring groove 2 in the vertical direction of the piston, when the elastic ring 4a is mounted on the ring groove 2, the diameter between the upper surface and the lower surface of the ring groove 2 is increased. Has no gap.

In the first embodiment, the blow-by gas flows from the combustion chamber through the gap 7 between the piston 1 and the cylinder liner 6 and further through the gap C1 between the synthetic resin ring 3 and the upper surface of the ring groove 2. Reaches the upper space 8 between the back surface of the synthetic resin ring 3 and the elastic ring 4a, but as described above, since there is no gap between the elastic ring 4a and the synthetic resin ring 3, the space 8 It cannot go down to the lower space 9 between the back surface of the synthetic resin ring 3 and the elastic ring 4a.

Also, since there is no gap between the elastic ring 4a and the upper surface of the ring groove 2, the space 8 does not go around the back surface of the elastic ring 4a to the space 9. Therefore, leakage of the blow-by gas to the crankcase is prevented.

As described above, in the first embodiment, the blow-by gas is prevented from rotating around the back surface of the synthetic resin ring 3 and leaking into the crankcase.

Since the space between the synthetic resin ring 3 and the cylinder liner 6 is also sealed, blow-by gas does not leak therefrom.

Further, since the elastic ring 4a and the expander ring 5 are integrated, the attachment to the piston 1 is easy.

FIG. 2 is a sectional view showing the structure of the second embodiment of the present invention.

In the second embodiment, the expander ring 5 is embedded in an elastic ring indicated by 4b. The operation and effect of the second embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

According to each of the above embodiments, since the space is formed between the expander ring 5 or the elastic rings 4a and 4b and the bottom wall h of the ring groove 2, the piston ring has a radius relative to the piston 1. The movement in the direction becomes easy. Therefore, the movement of the piston ring is free with respect to the radial movement of the piston 1 with respect to the cylinder liner 6.

The presence of an elastic ring between the synthetic resin ring 3 and the expander ring 5 allows the piston 1
When a force is exerted to swing the synthetic resin ring 3 instantaneously in the radial direction of the piston by the swinging motion, the force is absorbed by the elastic ring, and the force is absorbed by the elastic ring. The performance is improved.

Furthermore, the synthetic resin ring 3
The sliding surface with the cylinder liner 6 wears, and the expander ring 5 expands to lower the tension, but at the same time, if the elastic ring is rubber, the elastic ring swells due to lubricating oil to increase its thickness. The decrease in the tension can be compensated for, and the decrease in the tension of the entire piston ring can be prevented.

Although the present invention has been described with reference to the embodiment applied to an internal combustion engine as described above, the present invention is not limited to an internal combustion engine, but can be widely applied to other reciprocating compression machines and the like. It is.

[0022]

According to the present invention, there is provided a synthetic resin ring inserted into a ring groove formed on the outer peripheral surface of a piston, and an expander ring having self-tension and pressing the synthetic resin ring from inside to outside. In the piston ring,
Between the synthetic resin ring and the expander ring, an elastic ring having a vertical width greater than or equal to the width of the ring groove in the vertical direction of the piston is interposed, and the elastic ring includes the expander ring. This prevents the gas compressed by the piston from leaking into the crankcase around the back surface of the synthetic resin ring. And when assembling to a piston, since an expander ring and an elastic ring are assembled integrally, assembling is easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a first embodiment.

FIG. 2 is a sectional view showing the structure of a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Piston 2 ... Ring groove 3 ... Synthetic resin ring 4a ... Elastic ring (1st Example) 4b ... Elastic ring (2nd Example) 5 ... Expander ring 6 ... Cylinder liner

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masao Ishida 1-9-9 Yaesu, Chuo-ku, Tokyo Inside Teikoku Piston Ring Co., Ltd. (56) References JP-A-5-209685 (JP, A) 57-145747 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16J 9/28 F16J 9/06 F02F 5/00 301

Claims (1)

(57) [Claims] 1. A piston ring comprising: a synthetic resin ring inserted into a ring groove formed on an outer peripheral surface of a piston; and an expander ring having self-tension and pressing the synthetic resin ring from inside to outside. Between the synthetic resin ring and the expander ring, an elastic ring having a vertical width greater than or equal to the width of the ring groove in the vertical direction of the piston is interposed, and the elastic ring includes the expander ring. A piston ring characterized by the following.