JPS6229648Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention provides a piston ring for an internal combustion engine, particularly an inner circumferential surface of a cylinder hole formed in a cylinder block, which has an elliptical or oval cross section, and a cylinder hole having the same cross-sectional shape as the cylinder hole. The present invention relates to a piston ring that is installed in a piston ring groove formed on the outer peripheral surface of a piston in order to seal between the piston ring and the outer peripheral surface of the piston on which a piston pin is arranged along the longitudinal direction of the cross section.

An internal combustion engine in which a cylinder hole generally has a flat cross-sectional shape such as an oval or an oval shape, with both arcuate longitudinal ends and both sides having a smaller curvature than those ends and smoothly connecting to the ends. By opening a plurality of intake and exhaust valve ports in parallel in the longitudinal direction on the wall surface of a combustion chamber with a flat cross section, the total opening area of the intake and exhaust valve ports is reduced relative to the cross-sectional area of the cylinder hole. This is advantageous in increasing the intake and exhaust efficiency of the engine and increasing its output.

Piston rings applied to such internal combustion engines are flat, such as oval or elliptical, which have arcuate ends in the longitudinal direction and both ends that have a smaller curvature than those ends and smoothly connect to the ends. It is known that the shape is formed into a shape and has a cutting cut on one of the longitudinal ends, but in particular, the both sides having a small curvature and being relatively long have a large curvature and being relatively short in the longitudinal direction. It has lower torsional rigidity than both ends, and
Because the piston is likely to receive large side pressure from the cylinder hole due to the so-called oscillation phenomenon around the piston pin, twisting deformation is likely to occur on both sides during engine operation, and in this case, the outer circumferential surface A piston ring 13' formed at right angles to the upper and lower surfaces is inserted into the piston ring groove 11 of the piston 3.
When this is installed in the cylinder hole 2 of the cylinder block 1, when the piston ring 13' is twisted, the gas pressure in the combustion chamber 10 is applied to the outer peripheral end surface 20', and both sides become as shown in FIG. As shown by the chain line, it is bent inward and a large amount of blow-by gas is generated.

Therefore, the present invention solves the above-mentioned problem by inclining at least the outer circumferential end surfaces of both sides of an oval or oval-shaped piston ring from an upper surface close to the top surface of the piston to a lower surface farther from the top surface of the piston. The object of the present invention is to obtain a piston ring for an internal combustion engine.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, a cylinder hole 2 having an oval cross section is formed in a cylinder block 1. A shaped piston 3 is slidably fitted therein.
A piston pin 4 is horizontally mounted on the piston 3 along the longitudinal direction of its cross section, and the small ends of two connecting rods 5 are connected to the piston pin 4.
The large ends of these connecting rods 5 are connected to a crankshaft 6. 5' is another connecting rod connected to the crankshaft 6, which is connected to the piston 3 in another cylinder block 1 (not shown) which is arranged in a V-shape with the cylinder block 1.

A gasket 7 is installed on the top of the cylinder block 1.
A cylinder head 8 is attached through the cylinder head 8, and a combustion chamber 10 is formed by the combustion chamber wall 9 formed on the lower surface of the cylinder head 8 and the upper surface of the piston 3.

A piston ring groove 11 is provided on the outer periphery of the piston 3.
and an oil ring groove 12 are formed, respectively.
A piston ring 13 and an oil ring 14, which will be described later, are fitted into these grooves 11 and 12, respectively.

Next, the structure of the piston ring 13 of the present invention will be explained. As shown in FIG. It is formed into an oval shape having both side parts 17 and 18, and is cut at one end 15 in the longitudinal direction to form a cut slit 19.

Further, as shown in an enlarged view in FIG. 4, the outer peripheral end surface 20 of the piston ring 13 is inclined inward from an upper surface 21 close to the top surface of the piston 3 to a lower surface 22 farther from the top surface of the piston 3 when the piston ring 13 is assembled into the cylinder hole. It is formed as a tapered surface, and the optimum angle of inclination θ is in the range of about 1°30' to 5°.

Since the piston ring 13 of the present invention has the above-described configuration, when the piston 3 moves back and forth, the piston ring 13 slides into contact with the outer peripheral end surface 20 of the piston ring 13 and the inner peripheral surface of the cylinder hole 2 as shown in FIG. Even if it is twisted as shown, the outer peripheral end surface 20
The gas pressure in the combustion chamber 10 is not applied to the gas pressure in the combustion chamber 10.
However, there is no risk of bending deformation as shown by the chain line in Figure 3.

In the above, the case where the piston ring is formed into an oval shape has been described, but the piston ring has an elliptical shape having both arcuate longitudinal ends with a large curvature and both side parts with a small curvature that smoothly connect to both ends. The same applies to the case where it is formed into a flat shape such as.

As described above, according to the present invention, the inner circumferential surface of the cylinder hole 2 having an elliptical or oval cross section formed in the cylinder block 1, and the inner peripheral surface of the cylinder hole 2 having the same cross-sectional shape as the cylinder hole 2 and having the same cross-sectional shape as the cylinder hole 2, A piston ring groove 11 is formed on the outer circumferential surface of the piston 3 in order to seal between the outer circumferential surface of the piston 3 and the piston pin 4 disposed along the longitudinal direction.
A piston ring 13 that is attached to
The curvature is smaller than that of 5 and 16, and both ends 1
It is formed into an oval or oval shape having both side parts 17 and 18 smoothly connected to the ends 15 and 16, and has a cutout 19 at one of the longitudinal ends 15 and 16, and further has at least the both sides parts 17 and 16. 1
The outer peripheral end surfaces 20 of 7 and 18 range from an upper surface 21 close to the top surface of the piston 3 to a lower surface 22 farther from the top surface of the piston 3.
Since it is formed on a tapered surface that slopes inward toward the piston, its curvature is small and it is relatively long, resulting in low torsional rigidity.In addition, due to the so-called oscillation phenomenon around the piston pin 4 of the piston 3, lateral pressure is released from the cylinder hole 2. Even if torsional deformation occurs intensively on both sides 17 and 18 of the piston ring, which are particularly susceptible to deformation, during engine operation, the tapered outer circumferential end surfaces 20 of the both sides 17 and 18 can be extended over a wide range to the inner circumferential surface of the cylinder hole 2. It is possible to prevent the gas pressure inside the combustion chamber from directly acting on the outer peripheral end surface 20, and therefore, the both sides 17 and 18 are bent inward due to the gas pressure. Therefore, the amount of blow-by gas generated can be reduced as much as possible. Further, according to the torsional deformation of the piston ring side parts 17 and 18, the longitudinal section tapered gap between the outer circumferential end surface 20 and the inner circumferential surface of the cylinder hole 2 is closed.
When the oil on the inner circumferential surface of the cylinder hole 2 acts on the outer circumferential end surface 20 and causes the both side portions 17 and 18 to bend and deform inwardly, there is no problem, and oil rising due to the bending deformation can be suppressed. Moreover, since the piston ring side parts 17 and 18 are linear or relatively gently curved, although the outer peripheral end surface 20 is formed into a tapered surface, it is easy to process the taper, thereby reducing costs. can contribute to

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a vertical side view of an internal combustion engine equipped with a piston having an oval cross-section and equipped with the piston ring of the present invention, and FIG. 2 is a sectional view taken along the line shown in FIG. 1. , Fig. 3 is a plan view of the piston ring of the present invention, Fig. 4 is an enlarged sectional view taken along the line of Fig. 3, and Fig. 5 is a side view of the piston ring of the present invention installed in the piston ring groove on the outer periphery of the piston. FIG. 6 is an enlarged sectional view showing a state similar to that shown in FIG. 5 of a piston ring in which the outer circumferential end surface is formed perpendicular to the upper and lower surfaces for comparison. 1... Cylinder block, 2... Cylinder hole,
3... Piston, 4... Piston pin, 11...
Piston ring groove, 13... Piston ring, 1
5, 16...Both ends in the longitudinal direction, 17, 18...Both sides, 19...Cut cut, 20...Outer peripheral end surface, 2
1...Top surface, 22...Bottom surface.

Claims (1)

[Scope of utility model registration request] A piston pin 4 is formed on the inner circumferential surface of a cylinder hole 2 having an oval or oval cross section formed in the cylinder block 1 and having the same cross section as the cylinder hole 2 and along the longitudinal direction of the cross section. A piston ring 1 is installed in a piston ring groove 11 formed on the outer circumferential surface of the piston 3 in order to seal between the outer circumferential surface of the piston 3 and the piston ring 1.
3, both ends 15, 16 in the arc-shaped longitudinal direction
and both end portions 17 and 18 having a smaller curvature than the end portions 15 and 16 and smoothly connected to the end portions 15 and 16.
16, and furthermore, at least the outer circumferential end surfaces 20 of the both sides 17 and 18 are inclined inward from an upper surface 21 close to the top surface of the piston 3 to a lower surface 22 farther from the top surface of the piston 3. A piston ring for internal combustion engines formed with a tapered surface.