JP3988837B2 - Non-rotating structure of combination oil ring - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation preventing structure for a combined oil ring of an internal combustion engine.
[0002]
[Prior art]
A port hole is opened in the inner peripheral surface of the cylinder of the two-cycle engine. When the ring rotates in the circumferential direction and the abutment matches the port hole position, the ring abutment protrudes outward with self-tension. When the ring moves up and down in this state, the end of the joint may be caught in the port hole.
[0003]
Further, when the ring rotates in the engine with the cylinder shaft inclined horizontally or nearly horizontally, and the joint is located below, the lubricating oil enters the combustion chamber through the joint while the engine is stopped. When the engine is started in this state, white smoke is generated or the consumption of lubricating oil increases.
[0004]
Since the above-mentioned problem occurs when the ring rotates in the circumferential direction, a ring detent means may be employed.
[0005]
The use of ring stoppers in various engines is as follows.
・ Rolling stoppers are not generally used for construction machinery and marine diesel engines that do not start and stop frequently.
-Of the gasoline engines for automobiles that often start and stop, the rotation of the ring is generally adopted for engines with the cylinder shaft tilted horizontally or nearly horizontally.
・ Diesel engines with cylinders that are horizontal or inclined horizontally are rarely used for automobiles, so ring detents have not been adopted, but this type of engine has recently been used for automobiles. Has come to be used.
[0006]
And as a detent for a two-piece combination oil ring consisting of an oil ring and a coil expander,
1. Japanese Utility Model Publication No. 57-31546 is known. In Japanese Utility Model Laid-Open No. 57-31546, at both ends of a coil expander, a coil wire is projected and extended radially inward and outward, and this extended portion is formed in an oil hole and a piston formed in an oil ring. The anti-rotation means inserted into the oil relief holes is described.
[0007]
[Problems to be solved by the invention]
However, the anti-rotation structure has the following problems.
In general coil expanders, the outer peripheral surface of the coil expander is centerless polished to reduce the contact surface pressure between the coil expander and the oil ring. However, in the above structure, since the coil strands protrude in the radial direction at the end of the coil expander and protrude from the outer periphery of the coil expander, it is difficult to polish the outer peripheral surface of the coil expander.
・ Since the end face of the coil expander cannot be polished, the stability of the joint abutment is poor.
-Since the end face of the coil expander cannot be polished, the tension cannot be adjusted by changing the overall length of the coil expander by polishing the end face after forming the coil expander.
[0008]
An object of the present invention is to provide a detent structure for a combined oil ring that does not have the above-described problems.
[0009]
[Means for Solving the Problems]
In the combined oil ring, the oil ring and the coil expander are pressed against each other with a strong force in the radial direction. The circumferential frictional force generated by this force prevents the oil ring and the coil expander from rotating relatively. In an actual engine, it has never been experienced that the coil expander and the oil ring rotate independently during engine operation. Therefore, the anti-rotation of the combination oil ring can achieve its purpose if the rotation of the coil expander is prevented.
[0010]
Accordingly, the present invention has the following configuration. That is, a structure that prevents the combined oil ring composed of the oil ring and the coil expander from rotating in the circumferential direction within the oil ring groove of the piston,
The coil expander has a winding pitch over which a gap between adjacent strands is equal to or greater than the thickness of the joint wire over a predetermined length from one abutment end, and the other abutment end is adjacent. It is formed in a closed end where the matching strands are closed,
One end of the joint wire that is inserted across both ends of the coil expander is bent radially inward, and the other end extends along the circumferential hole of the coil expander. ,
One end of the joint wire that is bent protrudes radially inward from the coil expander through a gap between adjacent wires having a dimension equal to or larger than the thickness of the joint wire in the coil expander. It is characterized by being inserted into a recess or a through hole formed in the bottom surface of the oil ring groove of the piston.
[0011]
As described above, since the bent end portion is inserted into the recess or through hole formed in the bottom surface of the oil ring groove, the joint line is placed at a predetermined position in the circumferential direction in the oil ring groove. Maintained. And this joint wire is inserted across both joint ends of the coil expander, and the one end portion is inserted through a gap between adjacent strands of the coil expander. The line prevents rotation in the circumferential direction. As a result, the oil ring that the coil expander presses and urges in the radial direction is also prevented from rotating.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
1, 2, and 3, a rotation preventing structure for a two-piece combination oil ring that is an embodiment of the present invention will be described.
[0013]
The illustrated piston 1 is for a horizontally mounted engine in which a cylinder 2 is disposed horizontally, and a combination oil ring 10 is mounted in an oil ring groove 3 formed on the outer peripheral surface of the piston 1 in the cylinder 2. Has been. The combination oil ring 10 is a two-piece steel combination oil ring, and includes an oil ring 11 and a coil expander 12.
[0014]
The oil ring 11 is a steel ring having a substantially I-shaped cross section having a joint, and connects the pair of upper and lower rails 13 and 14 extending in the circumferential direction and the pair of rails 13 and 14 extending in the circumferential direction. It consists of a thin, straight web 15. The outer peripheral surfaces 16 and 17 of the upper and lower rails 13 and 14 constitute a sliding surface that contacts the inner peripheral surface 4 of the cylinder 2 and scrapes off the oil on the inner peripheral surface 4 of the cylinder 2. The outer peripheral groove 18 formed by the web 15 and the outer peripheral protrusions of the upper and lower rails 13 and 14 is an oil receiving groove, and the outer peripheral surfaces 16 and 17 of the upper and lower rails 13 and 14 are separated from the inner peripheral surface 4 of the cylinder 2. The scraped oil moves from the outer circumferential groove 18 to the inner circumferential side of the oil ring 11 through a plurality of oil holes 19 formed in the web 15 at equal intervals in the circumferential direction. The oil ring groove 3 is dropped into the oil pan through a plurality of oil relief holes (not shown) formed on the bottom surface 5 of the oil ring groove 3.
[0015]
A coil expander 12 is mounted in an inner circumferential groove 20 formed by the inner circumferential protrusions of the upper and lower rails 13 and 14 and the web 15, and presses the oil ring 11 radially outward. Have been to. The coil expander 12 is obtained by winding a wire having a rectangular cross section into a coil shape so that the rectangular cross section of the wire is vertically long in a direction perpendicular to the winding direction. The winding pitch of the coil expander 12 is set such that the gap 21 between adjacent strands is slightly larger than the thickness of the joint wire 27 described later. And one adjacent end 22 of the coil expander 12 has an adjacent strand open, that is, it is formed in an open end, while the other end 23 has an adjacent strand closed. That is, it is formed in a closed end, and end surfaces 24 and 25 of both joint end portions 22 and 23 are polished and formed in a plane parallel to the axial direction.
[0016]
A joint wire 27 is inserted into the circumferential hole 26 of the coil expander 12 across the pair of joint end portions 22 and 23 of the coil expander 12. The joint wire 27 (see FIG. 3) is made of steel or the like, and is an arc-shaped wire having substantially the same curvature as the coil expander 12, and has one end portion 27a bent inward in the radial direction. The other end does not bend in the radial direction and extends with substantially the same curvature as the coil expander 12, and the bent one end portion 27a passes through the gap 21 between the adjacent strands of the coil expander 12, Projecting radially inward from the coil expander 12.
[0017]
When the joint wire 27 is attached to the coil expander 12, the bent one end portion 27 a of the joint wire 27 is moved from the open end joint end portion 22 of the coil expander 12 to the gap 21 between adjacent strands. Insert one end portion 27 a radially inward from the coil expander 12 while rotating, and insert the other end of the joint wire 27 from the closed end joint end portion 23 of the coil expander 12 to the coil. It is inserted into the circumferential hole 26 of the expander 12.
[0018]
The coil expander 12 is mounted in the oil ring groove 3 of the piston 1 with the end faces 24 and 25 of the both end portions 22 and 23 being abutted and contracted to expand radially outward. To be produced. The oil ring 11 is pressed radially outward by the radially outward expansion force of the coil expander 12, and the outer peripheral surfaces 16 and 17 of the upper and lower rails 13 and 14 of the oil ring 11 are connected to the inner periphery of the cylinder 2. It is pressed against the surface 4. Further, one end portion 27 a of the joint wire 27 protruding inward in the radial direction from the coil expander 12 is inserted into a recess 28 formed in the bottom surface 5 of the oil ring groove 3 of the piston 1.
[0019]
The cross-sectional shape of the wire forming the coil expander 12 is not limited to the one shown above, and may be, for example, a circle. However, in carrying out the present invention, it is important that the strength of the bent end portion 27a of the joint line 27 is sufficient. For this purpose, it is desirable to use a thick joint line. For this purpose, it is desirable to make the cross-sectional shape of the wire of the coil expander 12 rectangular and increase the inner diameter of the circumferential hole 26 of the coil expander 12. If a coil having the same coil outer diameter, winding pitch, and spring constant is created using a circular and rectangular wire cross-sectional shape, the inner diameter of the rectangle can be increased.
[0020]
As described above, the joint line 27 is inserted in the recess 28 formed in the bottom surface 5 of the oil ring groove 3 at the bent end portion 27a. At a predetermined position. The joint wire 27 is inserted over both the joint end portions 22 and 23 of the coil expander 12, and the one end portion 27 a passes through the gap 21 between adjacent wires of the coil expander 12. Therefore, the coil expander 12 is prevented from rotating in the circumferential direction by the joint wire 27. As a result, the oil ring 11 pressed and urged by the coil expander 12 is also prevented from rotating in the circumferential direction.
[0021]
In the above embodiment, the recess 28 into which the one end portion 27a of the joint line 27 is inserted is formed in the bottom surface 5 of the oil ring groove 3. However, the recess 28 is not formed and the bottom surface 5 of the oil ring groove 3 is formed. You may make it insert the one end part 27a of the joint line 27 in the formed oil relief hole.
[0022]
Moreover, in the said embodiment, the winding pitch of the coil expander 12 was made constant except for the joint end part of a closed end. That is, the coil expander 12 has a winding pitch portion in which the gap 21 between adjacent strands is equal to or larger than the thickness of the joint wire 27, and the entire circumference of the coil expander 12 excluding the closed end joint end portion 23. However, the winding pitch may be partially different. For example, a few pitch portions near the open end joint end are set to a winding pitch such that the gap between adjacent strands is equal to or greater than the thickness of the joint wire, and other portions excluding the closed end joint end. The winding pitch can be made smaller than the winding pitch.
[0023]
【The invention's effect】
According to the present invention, the following effects can be obtained.
(1) It is possible to prevent the combined oil ring composed of the oil ring and the coil expander from rotating in the circumferential direction.
(2) The number of parts is small and assembly is easy.
(3) Since there is no projection in the radial direction on the coil expander, the outer periphery of the coil expander can be polished. As a result, the contact surface pressure between the coil expander and the oil ring can be reduced.
(4) Since one end of the coil expander is a closed end where the adjacent strands are closed, the end of the end can be polished to form a flat surface. The abutting state of the part can be stabilized, and the abutting abutting state is not changed.
(5) Since one end portion of the coil expander is a closed end in which the adjacent strands are closed, the end surface can be polished to form a flat surface. The tension can be easily adjusted by changing the total length of the coil expander by polishing the end face.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken at a right angle to the axial direction of a detent structure of a two-piece combination oil ring according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the axial direction of the rotation preventing structure of the combined oil ring.
FIG. 3 is a front view showing a joint line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piston 2 Cylinder 3 Oil ring groove 4 Cylinder inner peripheral surface 5 Oil ring groove bottom surface 10 Combination oil ring 11 Oil ring 12 Coil expander 13, 14 Rail 15 Web 16, 17 Outer surface 18 Outer groove 19 Oil hole 20 Inner groove 21 Gap 22, 23 Joint end 24, 25 Joint end face 26 Circumferential hole 27 Joint line 27a Joint line end 28 Recess

Claims (4)

A combined oil ring composed of an oil ring and a coil expander is configured to prevent circumferential rotation in the oil ring groove of the piston,
The coil expander has a winding pitch over which a gap between adjacent strands is equal to or greater than the thickness of the joint wire over a predetermined length from one abutment end, and the other abutment end is adjacent. It is formed in a closed end where the matching strands are closed,
One end of the joint wire that is inserted across both ends of the coil expander is bent radially inward, and the other end extends along the circumferential hole of the coil expander. ,
One end of the joint wire that is bent protrudes radially inward from the coil expander through a gap between adjacent wires having a dimension equal to or larger than the thickness of the joint wire in the coil expander. A structure for preventing rotation of a combined oil ring, wherein the structure is inserted into a recess or a through hole formed in the bottom surface of the oil ring groove of the piston. The coil expander has a winding pitch portion where the gap between adjacent strands is equal to or larger than the thickness of the joint wire over the entire circumference of the coil expander except the closed end joint end. The anti-rotation structure for a combined oil ring according to claim 1. The coil expander has a winding pitch portion in which a gap between adjacent strands is equal to or greater than the thickness of the joint wire. The anti-rotation structure for a combined oil ring according to claim 1, comprising: 4. The combined oil ring detent structure according to claim 1, wherein a cross-sectional shape of a wire of the coil expander is a rectangular shape.

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