JP2000274530A - Two-piece type combined oil ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-piece type combined oil ring capable of ensuring the movement of a side rail in an oil ring groove, and ensuring good sealing performance. SOLUTION: A spacer 10 and a side rail 20 constituting a two-piece type combined oil ring provided on a piston mechanism are produced in a crescent circular-nearly annular shape. The spacer 10 is of non-linear symmetrical cross section, and no slits radially notched are formed in it. the spacer has a fixed amount of twist in the axial direction. When the spacer 10 and the side rail 20 are inserted-fitted into an oil ring groove formed on a piston, and the side rail 20 anuts on the inner wall surface of a cylinder, the spacer 10 is pressed by the side rail 20 and the amount of twist of the spacer becomes zero. Thus, radial movement of the side rail 20 is not obstructed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-piece combination oil ring, and more particularly to a two-piece combination oil ring used for a high-speed, high-power engine.

[0002]

2. Description of the Related Art An oil ring provided on a piston mechanism of an engine of an automobile or the like that requires high rotation, high output, and low fuel consumption is a two-piece oil ring composed of one spacer expander and one side rail. Combination oil rings are well known in the art.

Japanese Patent Laid-Open Publication No. Sho 63-26463 discloses this two-piece combination oil ring. As shown in FIGS. 3 and 4, the oil ring has a structure in which a single side rail 120 is supported on the upper surface of a spacer expander 110, and these oil rings have oil ring grooves formed in a piston 130. And is inserted into the cylinder 140 together with the piston 130.

[0004] The spacer expander 110 and the side rail 120 are members each having an abutment separated at one place and having a substantially annular shape as a whole. The spacer expander 110 includes a base portion 111 having a flat base portion upper surface 111a on an upper portion, an outer peripheral portion 112, and an inner peripheral portion 113.
have. These are integrally formed and have a substantially U-shaped cross section with an opening formed upward. Inner mountain 1
13 is the height of the outer peripheral mountain portion 112 and the side rail 1
It is almost the same as the sum with the thickness of 20. Flat portions 112a and 113a are provided above the outer peripheral mountain portion 112 and the inner peripheral mountain portion 113.
The slope 112b and the side rail pressing surface 113b are formed from the flat portions 112a and 113a toward the base upper surface 111a, respectively.

The outer peripheral ridge 112 and the inner peripheral ridge 113 of the spacer expander 110 have slits 112 extending outward and inward in the radial direction of the spacer expander 110 to reach approximately half of the base 111.
c, 113c are formed. Slits 112c and 1
13c are alternately formed in the circumferential direction of the spacer expander 110.
The sum of the widths of 3c is such that it occupies 20 to 30% of the circumference of the spacer expander 110. This slit allows the spacer expander itself to have a radially outward expanding force, can cope with the undulation of the piston ring groove, and
The side rail 120 can follow the deformation 0a.

[0006]

However, when the above-mentioned conventional two-piece combination oil ring is inserted into the oil ring groove of the piston 130 and inserted into the cylinder 140, it is actually shown in FIG. It becomes such a state.
That is, the spacer expander 110, which has a non-linear cross-sectional shape, is twisted in a skirt shape by the tension of the spacer expander 110 trying to spread in the outer peripheral direction, and the side rail 120 has a radius Direction inner side and oil ring groove upper surface 130b
Direction and cannot move in the radial direction. For this reason, the side rail 120 is
The oil ring groove 40 does not follow the groove 40a, and the sealing performance is not only impaired, but also causes abnormal wear of the oil ring groove upper surface 130b.

If an oil ring is disclosed in Japanese Patent Laid-Open No. 4-783,
No. 76 is a three-piece combination oil ring of a type in which a spacer expander is sandwiched between two upper and lower side rails, and the spacer expander takes a shape like a spacer expander of the same type. In such a case, since the cross-sectional shape of the spacer expander is vertically symmetrical, no rotational moment is generated in the spacer expander itself due to the tension of the spacer expander. However, in the two-piece type combined oil ring, since the spacer expander is not symmetrical in the vertical direction, the above-described problem of twisting occurs.

Accordingly, an object of the present invention is to provide a two-piece combination oil ring which can ensure the movement of the side rail in the oil ring groove and can ensure good sealing performance.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a spacer for a piston mechanism having a piston and a cylinder, the spacer being inserted into an oil ring groove formed in the piston, and the insertion of the spacer. A substantially annular side rail that is inserted into the fitted oil ring groove, abuts against the spacer, is pressed radially outward of the piston by the self-tension of the spacer, and abuts on the inner wall surface of the cylinder; In the two-piece type combined oil ring, the outer peripheral surface and the inner peripheral surface of the spacer have no slits or recesses cut in the radial direction and have a self-tension without a substantially circular and non-linearly symmetric cross-sectional shape. And when the spacer is free from the action of external force, the spacer has a constant amount of twist in the axial direction of the piston. When the side rail and the spacer are inserted into the oil ring groove and the piston is inserted into the cylinder, and the side rail is in contact with the inner wall surface of the cylinder, the twist amount is We provide a two-piece combined oil ring that goes to zero.

Here, it is preferable that an outer peripheral ridge supporting the side rail protrudes in the axial direction from the axial end face at the radial outer peripheral end of the spacer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A two-piece combination oil ring according to a first embodiment of the present invention will be described with reference to FIGS.

The two-piece combination oil ring of the present invention comprises one spacer 10 and one side rail 20.
These are inserted into oil ring grooves formed in the piston 30 and inserted into the cylinder 40 together with the piston 30.

First, the spacer 10 and the side rail 20
Each configuration will be described. The spacer 10 and the side rails 20 are usually formed of steel by drawing or rolling, and have an abutment that is cut off at one place like a normal piston ring, and are generally formed in a partially circular shape. It is. As shown in FIG. 1, the side rail 20 is supported by the spacer 10 on the upper side of the spacer 10.

As shown in the cross-sectional view of FIG. 1, the spacer 10 has a base 11, an outer peripheral ridge 12, and an inner peripheral ridge 13.
have. These are integrally formed and have a substantially U-shaped cross section with an opening formed upward. Inner circumference mountain part 1
The height of 3 is smaller by 0.05 to 0.15 mm than the sum of the height of the outer peripheral mountain portion 12 and the thickness of the side rail 20 in the vertical direction. Upper portions of the base portion 11, the outer peripheral mountain portion 12, and the inner peripheral mountain portion 13 have flat portions 11a, 12a, and 13a. The flat portion 13a of the inner peripheral mountain portion 13 is horizontal, but the outer peripheral mountain portion 1
The second flat portion 12a has a slope that becomes lower toward the inside at an angle of 0 to 10 degrees with respect to the radial direction of the side rail. From the flat portions 12a and 13a, a slope 12b and a side rail pressing surface 13b are formed toward the base portion upper surface 11a. The side rail pressing surface 13b is formed by the spacer 1 and the side rail 2 as described later.
Is a portion that comes into contact with the side rail 2 when inserted into the oil ring groove, and has a slope that goes away from the axis downward at an angle of 5 to 25 degrees with respect to the axis of the spacer 10. ing.

The spacer 10 has a radially outward self-tension similar to a so-called compression ring, and unlike the conventional spacer expander, the outer peripheral surface and the inner peripheral surface of the spacer 10 have a radial direction. No slits or recesses are formed.
The spacer 10 has a fixed amount of twist such that the outer peripheral ridge 12 is located downward and the inner peripheral ridge 13 is located upward when free from a force from any direction. The amount of twist is such that when the spacer 10 and the side rail 20 are inserted into the oil ring groove as described later, the spacer 10 is twisted by the reaction force received by the side rail pressing surface 13b of the spacer 10 from the side rail 20. The amount is such that the amount becomes zero, and the value differs depending on the combined tension during operation and the shape and size of the spacer 10. For details on the design of spacers and side rails, such as the width of joints, self-tension, and the amount of twist, see Sankaido October 6, 1997, "Piston Rings for Automobiles."
And refer to it.

Next, the spacer 10 and the side rail 2
A description will be given of the insertion of the “0” into the oil ring groove. When the spacer 10 is inserted into the oil ring groove of the piston 30, the outer peripheral end of the base 11 is fixed to the oil ring groove lower surface 30 a by a fixed amount of twist of the spacer 10.
, And the inner peripheral end of the base portion 11 is
0a. Then, when the side rail 20 is inserted, a part of the side rail 20 on the radially inner side is pressed against the side rail pressing surface 13b and the oil ring groove upper surface 30.
b. The side rail pressing surface 13b is pressed by the reaction force of the side rail 20 against the self-tension of the spacer 10. Since the amount of twist of the spacer 10 during free time is small, the amount of twist of the spacer 10 is reduced to zero by pressing by the side rail 20, and the lower surface 10b of the spacer is horizontal. The side rail 20 is pressed in the outer peripheral direction of the spacer 10 by the radially outward self-tension by the spacer 10 and comes into contact with the inner wall surface 40a of the cylinder 40 as shown in FIG.

The spacer 10 has a constant twist amount, and when used as a two-piece type oil ring, the twist amount of the spacer 10 becomes 0. Therefore, the spacer 10 prevents the side rail 20 from moving in the radial direction. The side rail 10 can be always in contact with the cylinder inner wall surface 40a without hindrance. Therefore, even if the piston ring groove has undulation, or if the cylinder inner wall surface 40a is deformed, the cylinder inner wall surface 40a
The followability of the side rails 10 with respect to the direction is improved, and a high sealing property can be secured.

The two-piece combination oil ring according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, in the illustrated oil ring, the side rail is supported on the upper side of the spacer, but this vertical relationship may be reversed.

The spacer may be formed into an annular shape from a wire drawn or rolled into a deformed shape, and after the wire drawn from a rectangular shape or rolled into a shape is formed into a ring shape, the spacer is machined as shown in FIGS. It may be shaped as shown.

[0020]

According to the two-piece combination oil ring of the first aspect, a predetermined amount of twist is given to the spacer in advance, and when the spacer is inserted into the cylinder, the reaction force of the side rail with respect to the tension of the spacer causes the spacer to rotate. The amount of twist is reduced to zero, so that when the oil ring slides in the cylinder, the clearance between the upper surface of the oil ring groove and the upper surface of the side rail, or the clearance between the lower surface of the side rail and the flat surface of the outer peripheral ridge of the spacer. Clearance is maintained properly. For this reason, the spacer is tilted by the rotational moment generated by the reaction force of the tension received from the side rail, the side rail is pressed against the upper surface of the oil ring groove, and stable movement is inhibited, and abnormal wear of the oil ring groove occurs. Since such problems do not occur, good sealing performance can be ensured, and high output, low fuel consumption and low oil consumption of the internal combustion engine having the piston mechanism can be achieved.

According to the two-piece type oil ring of the second aspect, since the side rail is supported at one end of the outer peripheral hill, the side rail can be stably supported at a certain position on the spacer. , Good sealing performance can be secured. Further, it is possible to prevent wear of the side rail at an unspecified position. Furthermore, a desired posture of the side rail can be obtained only by precisely processing only the upper surface of the outer peripheral mountain portion.

[Brief description of the drawings]

FIG. 1 is a partial sectional perspective view showing a two-piece combination oil ring according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state in which the two-piece combination oil ring according to the embodiment of the present invention is mounted in an oil ring groove of a piston.

FIG. 3 is a partial sectional perspective view showing a conventional two-piece combination oil ring.

FIG. 4 is a cross-sectional view showing a state where a conventional two-piece combination oil ring is mounted in an oil ring groove of a piston and a side rail is immovable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Spacer 12 Outer peripheral mountain part 20 Side rail 30 Piston 40 Cylinder 40a Cylinder inner wall surface

Claims (2)

[Claims] 1. A spacer which is inserted into an oil ring groove formed in a piston of a piston mechanism having a piston and a cylinder, and which is inserted into the oil ring groove into which the spacer is inserted, and which contacts the spacer. A two-piece combined oil ring comprising a substantially annular side rail that is in contact with, is pressed radially outward of the piston by the self-tension of the spacer, and abuts the inner wall surface of the cylinder; The surface and the inner peripheral surface have no slits or recesses cut in the radial direction, and have a self-tensioning, substantially circular, annular and non-linearly symmetric cross-sectional shape, and the spacer is subjected to an external force. When free, the spacer has a constant amount of twist in the axial direction of the piston, and the side rail and the spacer are When the piston is inserted into the grayed groove is inserted in the cylinder and the inner wall surface of the side rail and the cylinder are in contact, 2, characterized in that the amount of twist becomes 0
Piece type combination oil ring. 2. A radially outer end of the spacer,
2. The two-piece combination oil ring according to claim 1, wherein an outer peripheral ridge supporting the side rail projects axially from an axial end face.