JP2016070118A - engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine capable of enhancing cooling efficiency of a piston head.SOLUTION: In an engine of this invention, a pressure ring 3 is fitted in a ring groove 2 of a piston head 1, and the pressure ring 3 is constituted by a top dead center side ring 4 and a bottom dead center side ring 5 mutually superposed. A step is provided on mutual contact surfaces 4a and 5a of the top dead center side ring 4 and the bottom dead center side ring 5, a step boundary surface 4b of the top dead center side ring 4 and a step boundary surface 5b of the bottom dead center side ring 5 are engaged with each other, an outer peripheral surface 4c of the top dead center side ring 4 is brought into contact with a cylinder wall 7, the step boundary surface 5b of the bottom dead center side ring 5 is fitted to the step boundary surface 4b of the top dead center side ring 4, and movement of the bottom dead center side ring 5 to the cylinder wall 7 side is restricted, and an outer peripheral surface 5c of the bottom dead center side ring 5 is separated from the cylinder wall 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine, and more particularly to an engine capable of increasing the cooling efficiency of a piston head.

  Conventionally, there is an engine in which a pressure ring is fitted in a ring groove of a piston head, and the pressure ring is composed of a top dead center side ring and a bottom dead center side ring that overlap each other (for example, Patent Document 1). reference).

  In this type of engine, even if the top dead center ring receives the gas pressure generated in the combustion chamber and the top dead center ring is distorted, the bottom dead center ring is unlikely to be distorted by the gas pressure. There is an advantage that the deterioration of the sealing performance of can be suppressed.

  The thing of this patent document 1 has a problem because the outer peripheral surface of the bottom dead center side ring is in contact with the cylinder wall and the outer peripheral surface of the top dead center side ring is separated from the cylinder wall.

Japanese Utility Model Publication No. 43-23202 (see FIGS. 2 and 3)

<Problem> The cooling efficiency of the piston head is low.
In this patent document 1, since the outer peripheral surface of the bottom dead center side ring is in contact with the cylinder wall and the outer peripheral surface of the top dead center side ring is separated from the cylinder wall, the piston top surface is heated by the piston head. It is conducted to the cylinder wall through the bottom dead center side ring far from the piston, and the cooling efficiency of the piston head is low.

  The subject of this invention is providing the engine which can improve the cooling efficiency of a piston head.

  As a result of research, the inventors of the present invention have focused on the fact that the cooling efficiency of the piston head increases when the outer peripheral surface of the top dead center side ring is in contact with the cylinder wall, and have reached the present invention.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1B, the pressure ring (3) is fitted in the ring groove (2) of the piston head (1), and the pressure ring (3) is overlapped with each other on the top dead center side ring ( 4) In the engine composed of the bottom dead center ring (5),
As illustrated in FIG. 1B, a step is provided on the mutual contact surfaces (4a) and (5a) of the top dead center side ring (4) and the bottom dead center side ring (5), and the top dead center side ring The step boundary surface (4b) of (4) and the step boundary surface (5b) of the bottom dead center side ring (5) are engaged with each other, and the outer peripheral surface (4c) of the top dead center side ring (4) is the cylinder wall. (7), the step boundary surface (5b) of the bottom dead center ring (5) is locked to the step boundary surface (4b) of the top dead center ring (4), and the bottom dead center ring (5 ) To the cylinder wall (7) side is limited, and the outer peripheral surface (5c) of the bottom dead center side ring (5) is separated from the cylinder wall (7).

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> The cooling efficiency of the piston head can be increased.
As illustrated in FIG. 1 (B), since the outer peripheral surface (4c) of the top dead center side ring (4) is in contact with the cylinder wall (7), the heat of the piston head (1) is high. It is conducted to the cylinder wall (7) through the top dead center side ring (4) close to (1a), and the cooling efficiency of the piston head (1) can be enhanced.

<Effect> The frictional resistance of the pressure ring against the cylinder wall can be reduced.
As illustrated in FIG. 1B, since the outer peripheral surface (5c) of the bottom dead center side ring (5) is separated from the cylinder wall (7), the pressure ring (3) and the cylinder wall (7) , The frictional resistance of the pressure ring (3) against the cylinder wall (6) can be reduced.

(Invention of Claim 2)
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> The cooling efficiency of the piston head can be increased.
Since the top dead center ring (4) is made of a material having higher thermal conductivity than the bottom dead center ring (5), the heat of the piston head (1) is high thermal conductivity. It is transmitted to the cylinder wall (7) via (4), and the cooling efficiency of the piston head (1) can be increased.

(Invention of Claim 3)
The invention according to claim 3 has the following effect in addition to the effect of the invention according to claim 1 or claim 2.
<Effect> The cooling efficiency of the piston head can be increased.
As illustrated in FIG. 1B, since the pressure ring (3) is fitted in the ring groove (2) on the top dead center side, the piston top surface is heated by the heat of the piston head (1). It is conducted to the cylinder wall (7) through the top dead center side ring (4) closest to (1a), and the cooling efficiency of the piston head (1) can be increased.

(Invention of Claim 4)
The invention according to claim 4 has the following effect in addition to the effect of the invention according to claim 3.
<Effect> A piston having a simple structure can be used.
As illustrated in FIG. 1B, since the land portion (9) without the ring groove is formed between the ring groove (2) and the oil ring groove (8), an intermediate ring groove such as a second ring is provided. It is possible to use a piston (11) having a simple structure without the above.

(Invention according to claim 5)
The invention according to claim 5 has the following effects in addition to the effects of the invention according to any one of claims 1 to 4.
<Effect> The sealing performance of the pressure ring can be improved.
As illustrated in FIG. 2, the gaps (4d) and (5d) of the top dead center side ring (4) and the bottom dead center side ring (5) are shifted from each other in the circumferential direction of the pressure ring (3). Since the bottom dead center side ring (5) or the top dead center side ring (4) overlapped with each gap gap (4d) (5d), the gap between each gap gap (4d) (5d) The blow-by gas can be prevented from being blown through, and the sealing performance of the pressure ring (3) can be improved.

(Invention of Claim 6)
The invention according to claim 6 has the following effect in addition to the effect of the invention according to claim 5.
<Effect> The sealing performance of the pressure ring can be improved.
As illustrated in FIG. 2, the gaps (4d) and (5d) between the top dead center ring (4) and the bottom dead center ring (5) are opposite to each other in the radial direction of the piston head (1). The blow-by gas that has passed through the joint gap (4d) of the top dead center ring (4) passes through the ring groove (2) and is opposite to the radial direction of the piston head (1). If it does not reach, it will not reach the joint gap (5d) of the bottom dead center ring (5), and blow-by gas blow-through through the ring groove (2) can be suppressed, and the pressure ring (3) Sealability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a diesel engine according to an embodiment of the present invention, in which FIG. 1 (A) is a schematic view of a main part, and FIG. 1 (B) is an enlarged longitudinal sectional view of a piston and a cylinder wall. It is the II-II sectional view taken on the line of FIG.

  FIGS. 1 and 2 are views for explaining an engine according to an embodiment of the present invention. In this embodiment, a direct injection vertical diesel engine will be described.

The outline of this engine is as follows.
As shown in FIG. 1 (A), in this engine, a cylinder head (12) is assembled on an upper portion of a cylinder wall (7), and a piston (11) is fitted in a cylinder bore. The piston (11) is connected to the crankshaft (14) via a connecting rod (13).
The cylinder head (12) is provided with an intake port (15) and an exhaust port (16), and a fuel injector (17) is attached.
The injection port of the fuel injector (17) is directed to the combustion chamber (10) surrounded by the cylinder head (12), the cylinder wall (7), and the piston (11).

  As shown in FIG. 1 (B), in this engine, the pressure ring (3) is fitted in the ring groove (2) of the piston head (1), and the pressure ring (3) overlaps the top dead center. It consists of a side ring (4) and a bottom dead center side ring (5).

  As shown in FIG. 1B, in this engine, a step is provided on the mutual contact surfaces (4a) and (5a) of the top dead center side ring (4) and the bottom dead center side ring (5), and the top dead center side The step boundary surface (4b) of the point side ring (4) and the step boundary surface (5b) of the bottom dead center side ring (5) are engaged with each other, and the outer peripheral surface (4c) of the top dead center side ring (4). Is in contact with the cylinder wall (7), and the step boundary surface (5b) of the bottom dead center side ring (5) is locked to the step boundary surface (4b) of the top dead center side ring (4), so that the bottom dead center side The movement of the ring (5) toward the cylinder wall (7) is restricted, and the outer peripheral surface (5c) of the bottom dead center ring (5) is separated from the cylinder wall (7).

In this engine, the top dead center side ring (4) is made of a material having higher thermal conductivity than the bottom dead center side ring (5).
An inexpensive cast iron is used for the bottom dead center side ring (5).
For the top dead center ring (4), alloy steel having higher thermal conductivity than the bottom dead center ring (5) is used. The surface of the alloy steel may be subjected to hard chrome plating with high thermal conductivity.

  As shown in FIG. 1B, in this engine, the pressure ring (3) is fitted in the ring groove (2) closest to the top dead center.

As shown in FIG. 1B, in this engine, a land portion (9) having no ring groove is formed between the ring groove (2) and the oil ring groove (8).
An oil ring (18) is fitted in the oil ring groove (8).

  As shown in FIG. 2, in this engine, the gaps (4d) (5d) between the top dead center side ring (4) and the bottom dead center side ring (5) are mutually connected to the circumference of the pressure ring (3). Arranged to be shifted in the direction.

  As shown in FIG. 2, in this engine, the gaps (4d) (5d) between the top dead center side ring (4) and the bottom dead center side ring (5) are arranged in the radial direction of the piston head (1). They are arranged on opposite sides.

(1) Piston head
(2) Ring groove
(3) Pressure ring
(4) Top dead center ring
(4a) Contact surface
(4b) Step boundary
(4c) Outer peripheral surface
(4d) Abutting gap
(5) Bottom dead center ring
(5a) Contact surface
(5b) Step boundary
(5c) Outer peripheral surface
(5d) Gap gap
(6) Cylinder center axis
(7) Cylinder wall
(8) Oil ring groove
(9) Land

Claims (6)

The pressure ring (3) is fitted in the ring groove (2) of the piston head (1), and the pressure ring (3) is overlapped with the top dead center side ring (4) and the bottom dead center side ring (5). In the engine consisting of
Steps are provided on the mutual contact surfaces (4a) and (5a) of the top dead center ring (4) and the bottom dead center ring (5), and the step boundary surface (4b) of the top dead center ring (4) The step boundary surface (5b) of the bottom dead center ring (5) is engaged with each other, the outer peripheral surface (4c) of the top dead center ring (4) is in contact with the cylinder wall (7), and the bottom dead center ring The step boundary surface (5b) of (5) is locked to the step boundary surface (4b) of the top dead center side ring (4), and the bottom dead center side ring (5) moves to the cylinder wall (7) side. And the outer peripheral surface (5c) of the bottom dead center side ring (5) is separated from the cylinder wall (7). The engine according to claim 1,
The engine characterized in that the top dead center ring (4) is made of a material having higher thermal conductivity than the bottom dead center ring (5). The engine according to claim 1 or 2,
The engine, wherein the pressure ring (3) is fitted in the ring groove (2) closest to the top dead center. The engine according to claim 3,
An engine characterized in that a land portion (9) having no ring groove is formed between the ring groove (2) and the oil ring groove (8). The engine according to any one of claims 1 to 4, wherein
The gap gaps (4d) and (5d) of the top dead center ring (4) and the bottom dead center ring (5) are arranged so as to be shifted from each other in the circumferential direction of the pressure ring (3). A featured engine. The engine according to claim 5, wherein
The gaps (4d) (5d) between the top dead center side ring (4) and the bottom dead center side ring (5) are arranged on the opposite sides in the radial direction of the piston head (1). A featured engine.

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