JP2017003052A

JP2017003052A - piston ring

Info

Publication number: JP2017003052A
Application number: JP2015119257A
Authority: JP
Inventors: 大志清水; Hiroshi Shimizu
Original assignee: Riken Corp
Current assignee: Riken Corp
Priority date: 2015-06-12
Filing date: 2015-06-12
Publication date: 2017-01-05
Anticipated expiration: 2035-06-12
Also published as: JP6579813B2

Abstract

PROBLEM TO BE SOLVED: To provide a piston ring capable of properly securing easiness in processing and sealability of an abutment portion.SOLUTION: In an abutment portion 3 of a piston ring 1, a side face 2a side of a main body portion 2 is provided with a first projecting portion 13 projecting from one abutment end portion 11 to the other abutment end portion 12, and a first receiving portion 14 receiving the first projecting portion 13 at the other abutment end portion 12. A side face 2b side of the main body portion 2 is provided with a second projecting portion 15 projecting from the other abutment end portion 12 toward one abutment end portion 11, and a second receiving portion 16 receiving the second projecting portion 15 at the one abutment end portion 11. A tip face 15a of the second projecting portion 15 is a curved surface having one of convex and concave shapes, and a tip face 16a of the second receiving portion 16 is a curved surface having the other of the convex and concave shapes, and corresponded to the curved shape of the tip face 15a of the second projecting portion 15.SELECTED DRAWING: Figure 3

Description

本発明は、内燃機関に用いられるピストンリングに関する。 The present invention relates to a piston ring used in an internal combustion engine.

自動車の内燃機関等に用いられるピストンリングは、例えばピストン外周面のリング溝に設けられ、ピストンリングの外周面がボア内周面に摺接し、かつピストンリングの一側面がリング溝の側面に当接することで燃焼室側からクランク室側へのブローバイガスの防止機能を有している。かかるピストンリングは、リング溝への装着の都合上、合口部を有する割りリング形状をなしているため、合口部におけるブローバイガスを抑制することが課題となっている。 Piston rings used in automobile internal combustion engines and the like are provided, for example, in a ring groove on the piston outer peripheral surface, the outer peripheral surface of the piston ring is in sliding contact with the inner peripheral surface of the bore, and one side surface of the piston ring contacts the side surface of the ring groove. By contacting, it has a function of preventing blow-by gas from the combustion chamber side to the crank chamber side. Since such a piston ring has a split ring shape having an abutment portion for the convenience of mounting in the ring groove, there is a problem of suppressing blow-by gas at the abutment portion.

このような課題に対し、例えば特許文献１に記載のピストンリングでは、合成樹脂製のピストンリングにステップ状の合口部を形成したものが開示されている。このピストンリングでは、幅方向及び厚さ方向のそれぞれにおいて一方の合口端部に凸部が、他方の合口端部に凹部が設けられている。この構成においては、凸部及び凹部の合せ面同士が閉鎖されることで、凸部及び凹部の合せ面同士の間を介してピストンリングの幅方向及び厚さ方向に漏れる流体の遮断を図り、ブローバイガスのシール性を向上している。 In response to such a problem, for example, a piston ring described in Patent Document 1 discloses a synthetic resin piston ring in which a stepped joint portion is formed. In this piston ring, in each of the width direction and the thickness direction, a convex portion is provided at one joint end, and a concave portion is provided at the other joint end. In this configuration, by closing the mating surfaces of the convex portion and the concave portion, the fluid leaking in the width direction and the thickness direction of the piston ring through between the mating surfaces of the convex portion and the concave portion is cut off, Blow-by gas sealing performance has been improved.

実開平４−４１１５３号公報Japanese Utility Model Publication No. 4-41153

上記特許文献１のような合口構造では、例えば厚さ方向において矩形の凹部及び凸部を形成しているため、複数の角部あるいは隅部が存在している。このため、合口構造の形成には高い加工精度が要求され、加工コストが上昇してしまう問題があった。ピストンリングの性能上、良好なシール性も必要となっており、合口部の加工容易性とシール性とを良好に確保できる技術が求められている。 In the joint structure as described in Patent Document 1, for example, rectangular recesses and projections are formed in the thickness direction, and therefore there are a plurality of corners or corners. For this reason, the formation of the abutment structure has a problem that high processing accuracy is required and the processing cost increases. In view of the performance of the piston ring, a good sealing property is also required, and a technique capable of ensuring good workability and sealing property of the joint portion is required.

本発明は、上記課題の解決のためになされたものであり、合口部の加工容易性とシール性とを良好に確保できるピストンリングを提供することを目的とする。 The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a piston ring that can satisfactorily ensure the workability and sealing performance of the joint portion.

本発明の一態様に係るピストンリングは、互いに対向する内周面及び外周面を有する環状の本体部と、本体部に形成された合口部とを備えたピストンリングであって、合口部において、本体部の一側面側には、一方の合口端部から他方の合口端部に向かって突出する第１の突出部と、他方の合口端部において第１の突出部を受ける第１の受け部とが設けられ、本体部の他側面側には、他方の合口端部から一方の合口端部に向かって突出する第２の突出部と、一方の合口端部において第２の突出部を受ける第２の受け部とが設けられ、第２の突出部の先端面は、凸状及び凹状の一方をなす湾曲面となっており、第２の受け部の先端面は、凸状及び凹状の他方をなすと共に、第２の突出部の先端面の湾曲形状に対応する湾曲面となっている。 A piston ring according to an aspect of the present invention is a piston ring including an annular main body portion having an inner peripheral surface and an outer peripheral surface facing each other, and a joint portion formed in the main body portion. On one side surface of the main body, a first projecting portion that projects from one abutment end toward the other abutment end, and a first receiving portion that receives the first projection at the other abutment end And a second projecting portion projecting from the other joint end portion toward the one joint end portion and the second projecting portion at the one joint end portion. A second receiving portion, and the tip surface of the second protrusion is a curved surface that is one of a convex shape and a concave shape, and the tip surface of the second receiving portion is a convex shape and a concave shape. The curved surface corresponding to the curved shape of the tip surface of the second protrusion is formed while forming the other.

このピストンリングでは、本体部の一側面側に位置する第２の突出部及び第２の受け部において、第２の突出部の先端面は、凸状及び凹状の一方をなす湾曲面となっており、第２の受け部の先端面は、凸状及び凹状の他方をなすと共に、第２の突出部の先端面の湾曲形状に対応する湾曲面となっている。これにより、第２の突出部及び第２の受け部に矩形の凸部及び凹部が設けられる場合と比較して、第２の突出部及び第２の受け部の先端面には角部、隅部が存在しなくなるので、合口部の加工容易性を確保できる。また、第２の突出部と第２の受け部との間に形成される厚さ方向のガス流路を長くできると共に、当該ガス流路が延在する方向をピストンリングの径方向から変化させることができる。これにより、該ガス流路での圧力損失が大きくなり、ピストンリングの厚さ方向へのガスの抜けを低減できる。さらには、このピストンリングでは、本体部の一側面側で第１の突出部及び第１の受け部が対向する位置と、本体部の他側面側で第２の突出部及び第２の受け部が対向する位置とが互いにずれることでクランクが形成されている。これにより、ピストンリングの使用時に、第１の突出部と第２の突出部とが本体部の幅方向に合わさりクランクが閉鎖することで、ピストンリングの幅方向に抜けるガスを遮断できる。したがって、上記ピストンリングによれば、合口部の加工容易性とシール性とを良好に確保できる。 In this piston ring, in the second projecting portion and the second receiving portion located on one side surface of the main body portion, the tip surface of the second projecting portion is a curved surface that forms one of a convex shape and a concave shape. The distal end surface of the second receiving portion is the other of the convex shape and the concave shape, and is a curved surface corresponding to the curved shape of the distal end surface of the second protruding portion. Thereby, compared with the case where a rectangular convex part and a recessed part are provided in a 2nd protrusion part and a 2nd receiving part, a corner | angular part and a corner are provided in the front end surface of a 2nd protrusion part and a 2nd receiving part. Since the portion does not exist, it is possible to ensure the ease of processing the joint portion. In addition, the gas flow passage in the thickness direction formed between the second protrusion and the second receiving portion can be lengthened, and the extending direction of the gas flow passage is changed from the radial direction of the piston ring. be able to. Thereby, the pressure loss in the gas flow path is increased, and the escape of gas in the thickness direction of the piston ring can be reduced. Furthermore, in this piston ring, the position where the first projecting portion and the first receiving portion face each other on the one side surface of the main body portion, and the second projecting portion and the second receiving portion on the other side surface side of the main body portion. The cranks are formed by shifting the positions of the two facing each other. As a result, when the piston ring is used, the first projecting portion and the second projecting portion are aligned with the width direction of the main body portion, and the crank is closed, so that gas that escapes in the width direction of the piston ring can be shut off. Therefore, according to the piston ring, it is possible to satisfactorily ensure the ease of processing and sealing performance of the joint portion.

また、第２の突出部の先端面は、内周面側を向く凹状の湾曲面となっており、第２の受け部の先端面は、外周面側を向く凸状の湾曲面となっていることが好ましい。ピストンの外周面にピストンリングを装着したときに、合口部の厚さ方向に流れるガスは、ピストンリングの径方向に沿って内周面側から外周面側に流れる。このとき、第２の突出部及び第２の受け部の先端面が上述した湾曲面となっているので、第２の突出部と第２の受け部との間に形成される厚さ方向のガス流路は、外周面側に向かうにしたがってピストンリングの径方向から周方向へと徐々に変化する。このように内周面側では、元々のガス流路の向きと、先端面間に形成されるガス流路の向きとが一致するため、ガスの滞留が抑制される。したがって、ガスの滞留の抑制により合口端部にヒートスポットが発生しにくくなり、合口部の摩耗及び破損が抑制される。 Further, the distal end surface of the second projecting portion is a concave curved surface facing the inner peripheral surface side, and the distal end surface of the second receiving portion is a convex curved surface facing the outer peripheral surface side. Preferably it is. When the piston ring is mounted on the outer peripheral surface of the piston, the gas flowing in the thickness direction of the joint portion flows from the inner peripheral surface side to the outer peripheral surface side along the radial direction of the piston ring. At this time, since the tip surfaces of the second projecting portion and the second receiving portion are the curved surfaces described above, the thickness direction formed between the second projecting portion and the second receiving portion is the same. The gas flow path gradually changes from the radial direction of the piston ring toward the circumferential direction toward the outer peripheral surface side. In this way, on the inner peripheral surface side, the original direction of the gas flow path and the direction of the gas flow path formed between the front end faces coincide with each other, so that gas retention is suppressed. Therefore, it becomes difficult to generate a heat spot at the abutment end due to the suppression of gas retention, and wear and breakage of the abutment are suppressed.

また、第２の突出部の先端面は、外周面側を向く凸状の湾曲面となっており、第２の受け部の先端面は、内周面側を向く凹状の湾曲面となっていることが好ましい。ピストンの外周面にピストンリングを装着したときに、合口部の厚さ方向に流れるガスは、ピストンリングの径方向に沿って内周面側から外周面側に流れる。このとき、第２の突出部及び第２の受け部の先端面が上述した湾曲面となっているので、第２の突出部と第２の受け部との間に形成される厚さ方向のガス流路は、外周面側に向かうにしたがってピストンリングの径方向から周方向へと徐々に変化する。このように内周面側では、元々のガス流路の向きと、先端面間に形成されるガス流路の向きとが一致するため、ガスの滞留が抑制される。したがって、ガスの滞留の抑制により合口端部にヒートスポットが発生しにくくなり、合口部の摩耗及び破損が抑制される。 Further, the distal end surface of the second projecting portion is a convex curved surface facing the outer peripheral surface side, and the distal end surface of the second receiving portion is a concave curved surface facing the inner peripheral surface side. Preferably it is. When the piston ring is mounted on the outer peripheral surface of the piston, the gas flowing in the thickness direction of the joint portion flows from the inner peripheral surface side to the outer peripheral surface side along the radial direction of the piston ring. At this time, since the tip surfaces of the second projecting portion and the second receiving portion are the curved surfaces described above, the thickness direction formed between the second projecting portion and the second receiving portion is the same. The gas flow path gradually changes from the radial direction of the piston ring toward the circumferential direction toward the outer peripheral surface side. In this way, on the inner peripheral surface side, the original direction of the gas flow path and the direction of the gas flow path formed between the front end faces coincide with each other, so that gas retention is suppressed. Therefore, it becomes difficult to generate a heat spot at the abutment end due to the suppression of gas retention, and wear and breakage of the abutment are suppressed.

また、第２の突出部の先端面は、外周面側を向く凹状の湾曲面となっており、第２の受け部の先端面は、内周面側を向く凸状の湾曲面となっていることが好ましい。この場合、一側面側から見て、第２の突出部及び第２の受け部のうち、より先鋭な形状を有する方が、内周面側に位置する。これにより、ピストンの外周面にピストンリングを装着したときに、合口部の摩耗及び破損が抑制される。加えて、合口部の厚さ方向に流れるガスは、ピストンリングの径方向に沿って内周面側から外周面側に向かう方向に流れる。このとき、第２の突出部及び第２の受け部の先端面が上述した湾曲面となっているので、第２の突出部と第２の受け部との間に形成される厚さ方向のガス流路は、外周面側に向かうにしたがってピストンリングの周方向から径方向へと徐々に変化する。このように内周面側では、元々のガス流路の向きと、先端面間に形成されるガス流路の向きとが大きくずれるため、ガスが他側面側の合口部に入りにくくなる。したがって、先端面間に形成されるガス流路を介したガスの抜けを一層確実に抑制できる。 Further, the distal end surface of the second projecting portion is a concave curved surface facing the outer peripheral surface side, and the distal end surface of the second receiving portion is a convex curved surface facing the inner peripheral surface side. Preferably it is. In this case, when viewed from the one side surface, of the second projecting portion and the second receiving portion, the one having a sharper shape is located on the inner peripheral surface side. Thereby, when a piston ring is mounted on the outer peripheral surface of the piston, wear and damage of the joint portion are suppressed. In addition, the gas flowing in the thickness direction of the joint portion flows in the direction from the inner peripheral surface side toward the outer peripheral surface side along the radial direction of the piston ring. At this time, since the tip surfaces of the second projecting portion and the second receiving portion are the curved surfaces described above, the thickness direction formed between the second projecting portion and the second receiving portion is the same. The gas flow path gradually changes from the circumferential direction of the piston ring toward the radial direction toward the outer peripheral surface side. As described above, on the inner peripheral surface side, the original direction of the gas flow path and the direction of the gas flow path formed between the front end surfaces are greatly deviated, so that it is difficult for the gas to enter the abutment portion on the other side surface side. Therefore, the escape of gas through the gas flow path formed between the front end surfaces can be more reliably suppressed.

また、第２の突出部の先端面は、内周面側を向く凸状の湾曲面となっており、第２の受け部の先端面は、外周面側を向く凹状の湾曲面となっていることが好ましい。この場合、一側面側から見て、第２の突出部及び第２の受け部のうち、より先鋭な形状を有する方が、内周面側に位置する。これにより、ピストンの外周面にピストンリングを装着したときに、合口部の摩耗及び破損が抑制される。加えて、合口部の厚さ方向に流れるガスは、ピストンリングの径方向に沿って内周面側から外周面側に向かう方向に流れる。このとき、第２の突出部及び第２の受け部の先端面が上述した湾曲面となっているので、第２の突出部と第２の受け部との間に形成される厚さ方向のガス流路は、外周面側に向かうにしたがってピストンリングの周方向から径方向へと徐々に変化する。このように内周面側では、元々のガス流路の向きと、先端面間に形成されるガス流路の向きとが大きくずれるため、ガスが他側面側の合口部に入りにくくなる。したがって、先端面間に形成されるガス流路を介したガスの抜けを一層確実に抑制できる。 Further, the distal end surface of the second projecting portion is a convex curved surface facing the inner peripheral surface side, and the distal end surface of the second receiving portion is a concave curved surface facing the outer peripheral surface side. Preferably it is. In this case, when viewed from the one side surface, of the second projecting portion and the second receiving portion, the one having a sharper shape is located on the inner peripheral surface side. Thereby, when a piston ring is mounted on the outer peripheral surface of the piston, wear and damage of the joint portion are suppressed. In addition, the gas flowing in the thickness direction of the joint portion flows in the direction from the inner peripheral surface side toward the outer peripheral surface side along the radial direction of the piston ring. At this time, since the tip surfaces of the second projecting portion and the second receiving portion are the curved surfaces described above, the thickness direction formed between the second projecting portion and the second receiving portion is the same. The gas flow path gradually changes from the circumferential direction of the piston ring toward the radial direction toward the outer peripheral surface side. As described above, on the inner peripheral surface side, the original direction of the gas flow path and the direction of the gas flow path formed between the front end surfaces are greatly deviated, so that it is difficult for the gas to enter the abutment portion on the other side surface side. Therefore, the escape of gas through the gas flow path formed between the front end surfaces can be more reliably suppressed.

また、第２の突出部の先端面、及び第２の受け部の先端面は、一方の合口端部と他方の合口端部とを正対させたときに、一側面側から見た第２の突出部と第２の受け部との隙間が内周面側から外周面側に向かって狭くなるように湾曲していることが好ましい。ピストンの外周面にピストンリングを装着したときに、ピストンリングの合口部において厚さ方向に流れるガスは、内周面側から外周面側に向かって流れる。したがって、上記隙間が内周面側から外周面側に向かって狭くなるように互いの先端面が湾曲していることにより、上記ガスの抜けを一層確実に抑制できる。 Further, the front end surface of the second protrusion and the front end surface of the second receiving part are the second viewed from one side when the one abutment end and the other abutment end face each other. It is preferable that the gap between the protruding portion and the second receiving portion is curved so as to become narrower from the inner peripheral surface side toward the outer peripheral surface side. When the piston ring is mounted on the outer peripheral surface of the piston, the gas flowing in the thickness direction at the joint portion of the piston ring flows from the inner peripheral surface side toward the outer peripheral surface side. Therefore, the escape of the gas can be more reliably suppressed by curving the tip surfaces so that the gap becomes narrower from the inner peripheral surface side toward the outer peripheral surface side.

また、第２の突出部の幅が先端側に向かって狭くなるように、第２の突出部における第１の突出部との合わせ面が、第１の突出部における第２の突出部との合わせ面に対して傾斜していることが好ましい。この場合、第１の突出部と第２の突出部とによって形成されるクランクの長さを十分に確保できるので、クランクでの圧力損失が大きくなり、ピストンリングの幅方向へのガスの抜けを一層確実に抑制できる。また、第２の突出部の基端部が肉厚になるため、第２の突出部の強度をより確保することが可能となる。 Further, the mating surface of the second protrusion with the first protrusion is so that the width of the second protrusion becomes narrower toward the tip side. It is preferable to be inclined with respect to the mating surface. In this case, since the length of the crank formed by the first protrusion and the second protrusion can be sufficiently secured, the pressure loss at the crank increases, and gas escapes in the width direction of the piston ring. It can suppress more reliably. Further, since the base end portion of the second protrusion is thick, it is possible to further secure the strength of the second protrusion.

また、第１の受け部の先端面が、第１の突出部の先端面に対して傾斜していることが好ましい。これにより、先端面同士の接触を回避でき、第１の突出部の摩耗を抑制できる。 Moreover, it is preferable that the front end surface of a 1st receiving part inclines with respect to the front end surface of a 1st protrusion part. Thereby, the contact of front-end | tip surfaces can be avoided and abrasion of a 1st protrusion part can be suppressed.

また、第２の突出部の先端面が、第２の受け部の先端面に対して傾斜していることが好ましい。これにより、先端面同士の接触を回避でき、第２の突出部の摩耗を抑制できる。 Moreover, it is preferable that the front end surface of the 2nd protrusion part inclines with respect to the front end surface of a 2nd receiving part. Thereby, the contact of front-end | tip surfaces can be avoided and abrasion of a 2nd protrusion part can be suppressed.

また、本体部は、金属又は合金によって形成されていることが好ましい。これにより、ピストンリングの耐熱性を十分に確保できる。 Moreover, it is preferable that the main-body part is formed with the metal or the alloy. Thereby, sufficient heat resistance of the piston ring can be ensured.

本発明に係るピストンリングによれば、合口部の加工容易性とシール性とを良好に確保できる。 According to the piston ring according to the present invention, it is possible to satisfactorily ensure the processability and sealing performance of the joint portion.

本発明の一態様に係るピストンリングの一実施形態を示す斜視図である。It is a perspective view showing one embodiment of a piston ring concerning one mode of the present invention. 図１に示したピストンリングの合口部を一側面側から示す要部拡大斜視図である。It is a principal part expansion perspective view which shows the joint part of the piston ring shown in FIG. 1 from the one side surface side. 図１に示したピストンリングの合口部を他側面側から示す要部拡大斜視図である。It is a principal part expansion perspective view which shows the joint part of the piston ring shown in FIG. 1 from the other side surface side. 図１に示したピストンリングの合口部を他側面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring shown in FIG. 1 from the other side surface side. 図１に示したピストンリングの合口部を外周面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring shown in FIG. 1 from the outer peripheral surface side. 第１変形例〜第３変形例に係るピストンリングの合口部を他側面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring which concerns on a 1st modification-a 3rd modification from the other side surface side. 第４変形例に係るピストンリングの合口部を他側面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring which concerns on a 4th modification from the other side surface side. 第５変形例に係るピストンリングの合口部を他側面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring which concerns on a 5th modification from the other side surface side. 第６変形例に係るピストンリングの合口部を外周面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring which concerns on a 6th modification from the outer peripheral surface side. 第７変形例に係るピストンリングの合口部を外周面側から見た要部拡大図である。It is the principal part enlarged view which looked at the joint part of the piston ring which concerns on a 7th modification from the outer peripheral surface side.

以下、図面を参照しながら、本発明の一態様に係るピストンリングの好適な実施形態について詳細に説明する。 Hereinafter, preferred embodiments of a piston ring according to an aspect of the present invention will be described in detail with reference to the drawings.

図１は、本発明の一態様に係るピストンリングの一実施形態を示す斜視図である。同図に示すピストンリング１は、例えば自動車の内燃機関においてピストン外周面のリング溝に設けられる。ピストンリング１の外周面２ｄがボア内周面に摺接し、かつピストンリング１の側面２ｂ側がリング溝の側面に当接してシール面となることで、燃焼室側からクランク室側へのブローバイガスの防止機能を奏するようになっている。 FIG. 1 is a perspective view illustrating an embodiment of a piston ring according to an aspect of the present invention. A piston ring 1 shown in the figure is provided in a ring groove on an outer peripheral surface of a piston in an internal combustion engine of an automobile, for example. The blow-by gas from the combustion chamber side to the crank chamber side is obtained when the outer peripheral surface 2d of the piston ring 1 is in sliding contact with the inner peripheral surface of the bore and the side surface 2b of the piston ring 1 is in contact with the side surface of the ring groove to form a seal surface. It is designed to prevent this.

このピストンリング１は、環状の本体部２と、本体部２の一部に形成された合口部３とを備えている。本体部２は、幅方向の端面である側面（一側面）２ａ及び側面（他側面）２ｂと、厚さ方向の端面である内周面２ｃ及び外周面２ｄとによって、厚さ方向が長辺かつ幅方向が短辺となる断面略長方形状をなしている。この本体部２は、例えば金属又は合金（複数の金属元素を含有する鋳鉄或いは鋼材）によって十分な強度、耐熱性、及び弾性をもって形成されている。また、本体部２の表面には、例えば硬質クロムめっき層、クロムの窒化物層、或いは鉄の窒化物層などによる表面改質が施され、本体部２の耐摩耗性の向上が図られている。 The piston ring 1 includes an annular main body 2 and an abutment 3 formed at a part of the main body 2. The main body 2 has a long side in the thickness direction by a side surface (one side surface) 2a and a side surface (other side surface) 2b which are end surfaces in the width direction, and an inner peripheral surface 2c and an outer peripheral surface 2d which are end surfaces in the thickness direction. In addition, the cross section has a substantially rectangular shape with a short side in the width direction. The main body 2 is formed of a metal or an alloy (a cast iron or steel material containing a plurality of metal elements) with sufficient strength, heat resistance, and elasticity. Further, the surface of the main body 2 is subjected to surface modification by, for example, a hard chromium plating layer, a chromium nitride layer, or an iron nitride layer, so that the wear resistance of the main body 2 is improved. Yes.

図２は、図１に示したピストンリング１の合口部３を側面２ａ側から示す要部拡大斜視図であり、図３は、図１に示したピストンリング１の合口部３を側面２ｂ側から示す要部拡大斜視図である。図４は、図１に示したピストンリングの合口部３を側面２ｂ側から見た要部拡大図である。図２〜４に示すように、合口部３は、本体部２の一部に形成された切れ目であり、ピストンリング１をピストン外周面のリング溝に装着する際の装着性の確保を目的として設けられている。合口部３では、ピストンリング１をリング溝に装着する前の状態において、一方の合口端部１１と他方の合口端部１２とが所定の間隔をもって互いに対向した状態となっている。 2 is an enlarged perspective view of a main part showing the joint portion 3 of the piston ring 1 shown in FIG. 1 from the side surface 2a side, and FIG. 3 shows the joint portion 3 of the piston ring 1 shown in FIG. 1 on the side surface 2b side. It is a principal part expansion perspective view shown from. FIG. 4 is an enlarged view of a main part when the joint portion 3 of the piston ring shown in FIG. 1 is viewed from the side surface 2b side. As shown in FIGS. 2 to 4, the joint portion 3 is a cut formed in a part of the main body portion 2, and for the purpose of ensuring the mounting property when the piston ring 1 is mounted in the ring groove on the piston outer peripheral surface. Is provided. In the abutment portion 3, one abutment end portion 11 and the other abutment end portion 12 face each other with a predetermined interval before the piston ring 1 is mounted in the ring groove.

この合口部３において、図２に示すように、本体部２の側面２ａ側には、一方の合口端部１１から他方の合口端部１２に向かって突出する第１の突出部１３と、他方の合口端部１２において第１の突出部１３を受ける第１の受け部１４とが設けられている。より具体的には、第１の突出部１３では、一方の合口端部１１から本体部２の側面２ａ側の略半分部分が断面略長方形状に突出した状態となっている。第１の受け部１４では、他方の合口端部１２において本体部２の側面２ａ側の略半分部分が第１の突出部１３の形状に対応して断面略長方形状に切り欠かれた状態となっている。したがって、第１の突出部１３における第１の受け部１４との対向面である先端面１３ａ、及び第１の受け部１４における第１の突出部１３との対向面である先端面１４ａは、それぞれ周方向に対して垂直又は略垂直に延在する略長方形状である。側面２ａ側においては、第１の突出部１３及び第１の受け部１４によっていわゆるストレート合口が形成されている。 In this abutment portion 3, as shown in FIG. 2, on the side surface 2a side of the main body 2, a first projection portion 13 that projects from one abutment end portion 11 toward the other abutment end portion 12 and the other A first receiving portion 14 that receives the first protruding portion 13 is provided at the joint end portion 12. More specifically, in the first projecting portion 13, a substantially half portion on the side surface 2 a side of the main body portion 2 protrudes from the one end portion 11 in a substantially rectangular cross section. In the first receiving portion 14, a state in which a substantially half portion on the side surface 2 a side of the main body portion 2 is cut out into a substantially rectangular cross section corresponding to the shape of the first protruding portion 13 in the other joint end portion 12. It has become. Therefore, the front end surface 13a that is the surface facing the first receiving portion 14 in the first protrusion 13 and the front end surface 14a that is the surface facing the first protrusion 13 in the first receiving portion 14 are: Each has a substantially rectangular shape extending perpendicularly or substantially perpendicular to the circumferential direction. On the side surface 2 a side, a so-called straight joint is formed by the first projecting portion 13 and the first receiving portion 14.

また、図３及び図４に示すように、本体部２の側面２ｂ側には、他方の合口端部１２から一方の合口端部１１に向かって突出する第２の突出部１５と、一方の合口端部１１において第２の突出部１５を受ける第２の受け部１６とが設けられている。より具体的には、第２の突出部１５は、第２の受け部１６との対向面である先端面１５ａが内周面２ｃ側を向く凹状の湾曲面となるように、第２の受け部１６に向かって突出した状態となっている。つまり、第２の突出部１５の先端面１５ａは、ピストンリング１の幅方向から見て内周面２ｃ側から外周面２ｄ側にかけて、第２の受け部１６に向かって突出度合が大きくなるように湾曲している。第２の受け部１６は、第２の突出部１５との対向面である先端面１６ａが外周面２ｄ側を向く凸状の湾曲面となるように、第２の突出部１５の先端面１５ａの湾曲形状に対応して切り欠かれた状態となっている。よって、第２の受け部１６の先端面１６ａは、ピストンリング１の幅方向から見て、第２の突出部１５の先端面１５ａの湾曲形状に隙間なく接触可能に湾曲している。 Moreover, as shown in FIG.3 and FIG.4, the 2nd protrusion part 15 which protrudes toward the one abutment edge part 11 from the other abutment edge part 12 on the side surface 2b side of the main-body part 2, and one A second receiving portion 16 that receives the second projecting portion 15 is provided at the joint end portion 11. More specifically, the second protrusion 15 has a second receiving portion so that the tip surface 15a, which is a surface facing the second receiving portion 16, becomes a concave curved surface facing the inner peripheral surface 2c. It protrudes toward the part 16. That is, the leading end surface 15a of the second projecting portion 15 has a degree of projecting toward the second receiving portion 16 from the inner peripheral surface 2c side to the outer peripheral surface 2d side when viewed from the width direction of the piston ring 1. Is curved. The second receiving portion 16 has a distal end surface 15a of the second projecting portion 15 such that the distal end surface 16a, which is a surface facing the second projecting portion 15, becomes a convex curved surface facing the outer peripheral surface 2d side. It is in a state of being cut out corresponding to the curved shape. Therefore, when viewed from the width direction of the piston ring 1, the distal end surface 16 a of the second receiving portion 16 is curved so as to be able to contact the curved shape of the distal end surface 15 a of the second projecting portion 15 without a gap.

図４に示すように、側面２ｂ側から見た先端面１５ａ，１６ａは、弧状となっている。先端面１５ａと先端面１６ａとは、合口端部１１，１２同士を正対させたときに、側面２ｂ側から見た第２の突出部１５と第２の受け部１６との隙間の距離ｄ１が一定になるように湾曲している。 As shown in FIG. 4, the front end surfaces 15a and 16a viewed from the side surface 2b are arcuate. The front end surface 15a and the front end surface 16a have a gap distance d1 between the second projecting portion 15 and the second receiving portion 16 as viewed from the side surface 2b when the abutting end portions 11 and 12 are opposed to each other. Is curved to be constant.

側面２ｂ側においては、第２の突出部１５の先端面１５ａ及び第２の受け部１６の先端面１６ａによって、ストレート合口とは異なる形状の合口が形成されている。第２の突出部１５は、第２の受け部１６よりも先鋭な形状である先鋭部分２１を有している。この先鋭部分２１は、外周面２ｄ側に位置しており、第２の受け部１６に向かって先細りとなっている。先鋭部分２１に研磨又は面取り等が施され、先鋭部分２１の少なくとも一部が除去されてもよい。これにより、ピストンリング１をピストンの外周に装着して先鋭部分２１がシリンダに衝突したとしても、該先鋭部分２１の摩耗及び破損を抑制できる。 On the side surface 2 b side, a joint having a shape different from the straight joint is formed by the tip surface 15 a of the second protrusion 15 and the tip surface 16 a of the second receiving part 16. The second protruding portion 15 has a sharpened portion 21 having a sharper shape than the second receiving portion 16. The sharpened portion 21 is located on the outer peripheral surface 2 d side and is tapered toward the second receiving portion 16. The sharpened portion 21 may be polished or chamfered, and at least a part of the sharpened portion 21 may be removed. Thereby, even if the piston ring 1 is mounted on the outer periphery of the piston and the sharp portion 21 collides with the cylinder, wear and breakage of the sharp portion 21 can be suppressed.

以上のような構成を有するピストンリング１では、第２の突出部１５及び第２の受け部１６には厚さ方向において矩形の凸部及び凹部が設けられない。これにより、第２の突出部１５及び第２の受け部１６に角部あるいは隅部が形成される場合と比較して、第２の突出部１５及び第２の受け部１６の先端面１５ａ，１６ａには角部、隅部が存在しなくなる。したがって、例えば加工治具の挿入角度及び大きさ等の制限が緩くなり、側面２ｂ側における合口部３の加工容易性を確保できる。また、第２の突出部１５と第２の受け部１６との間に形成される厚さ方向のガス流路は、例えば第１の突出部１３と第１の受け部１４によって形成されるストレート合口と比較して長くなる。これにより、ピストンリング１の厚さ方向のガス流路を長くできると共に、当該ガス流路が延在する方向をピストンリング１の径方向から変化させることができる。したがって、該ガス流路での圧力損失が大きくなり、ピストンリング１の厚さ方向へのガスの抜けを低減できる。 In the piston ring 1 having the above-described configuration, the second projecting portion 15 and the second receiving portion 16 are not provided with rectangular convex portions and concave portions in the thickness direction. Thereby, compared with the case where a corner | angular part or a corner | angular part is formed in the 2nd protrusion part 15 and the 2nd receiving part 16, the front end surface 15a of the 2nd protrusion part 15 and the 2nd receiving part 16, There are no corners or corners in 16a. Therefore, for example, restrictions on the insertion angle and size of the processing jig are relaxed, and the ease of processing of the joint portion 3 on the side surface 2b side can be ensured. Further, the gas flow path in the thickness direction formed between the second projecting portion 15 and the second receiving portion 16 is, for example, a straight formed by the first projecting portion 13 and the first receiving portion 14. It becomes longer compared to the entrance. Thereby, the gas flow path in the thickness direction of the piston ring 1 can be lengthened, and the direction in which the gas flow path extends can be changed from the radial direction of the piston ring 1. Therefore, the pressure loss in the gas flow path is increased, and the escape of gas in the thickness direction of the piston ring 1 can be reduced.

また、本体部２の側面２ａ側で第１の突出部１３及び第１の受け部１４が対向する位置と、本体部２の側面２ｂ側で第２の突出部１５及び第２の受け部１６が対向する位置とが、本体部２の周方向に互いにずれている。これにより、合口部３を外周面２ｄ側から見た場合、図５に示すように、第１の突出部１３の先端面１３ａ、第１の受け部１４の先端面１４ａ、第１の突出部１３における第２の突出部１５との合わせ面１３ｂ、第２の突出部１５における第１の突出部１３との合わせ面１５ｂ、第２の突出部１５の先端面１５ａ、及び第２の受け部１６の先端面１６ａによってクランクＣ１が形成されている。 Further, the position where the first protruding portion 13 and the first receiving portion 14 face each other on the side surface 2 a side of the main body portion 2, and the second protruding portion 15 and the second receiving portion 16 on the side surface 2 b side of the main body portion 2. Are opposed to each other in the circumferential direction of the main body 2. Thereby, when the abutment portion 3 is viewed from the outer peripheral surface 2d side, as shown in FIG. 5, the front end surface 13a of the first projecting portion 13, the front end surface 14a of the first receiving portion 14, and the first projecting portion. 13, the mating surface 13 b with the second projecting portion 15, the mating surface 15 b of the second projecting portion 15 with the first projecting portion 13, the tip surface 15 a of the second projecting portion 15, and the second receiving portion. A crank C1 is formed by the 16 front end surfaces 16a.

したがって、ピストンリング１がピストン外周面のリング溝に装着されてピストンの上下運動による荷重を受けた場合に、第１の突出部１３の合わせ面１３ｂと第２の突出部１５の合わせ面１５ｂとが本体部２の幅方向に合わさり、クランクＣ１が閉鎖することで、ピストンリング１の幅方向に抜けるガスを遮断できる。 Therefore, when the piston ring 1 is mounted in the ring groove on the piston outer peripheral surface and receives a load due to the vertical movement of the piston, the mating surface 13b of the first projecting portion 13 and the mating surface 15b of the second projecting portion 15 Are aligned in the width direction of the main body 2 and the crank C1 is closed, whereby the gas that escapes in the width direction of the piston ring 1 can be blocked.

また、ピストンリング１では、第２の突出部１５及び第２の受け部１６には矩形の凸部及び凹部が形成されず、先端面１５ａ，１６ａが湾曲面となっている。このため、ピストンリング１に突き当たり等が生じた場合、湾曲面である先端面１５ａが湾曲面である先端面１６ａの表面を滑りやすくなり、互いの先端面１５ａ，１６ａにかかる応力が特定の箇所に集中しにくくなる。加えて、第１の突出部１３は第２の突出部１５よりも突出しているため、第２の突出部１５が片持ち構造とならずに第１の突出部１３によって支持される。このような構造により、合口部３の強度を確保できる。 Further, in the piston ring 1, the second protrusion 15 and the second receiving part 16 are not formed with rectangular convex parts and concave parts, and the front end faces 15a, 16a are curved surfaces. For this reason, when the piston ring 1 is abutted or the like, the distal end surface 15a which is a curved surface becomes easy to slide on the surface of the distal end surface 16a which is a curved surface, and the stress applied to the distal end surfaces 15a and 16a is a specific location. It becomes difficult to concentrate on. In addition, since the 1st protrusion part 13 protrudes rather than the 2nd protrusion part 15, the 2nd protrusion part 15 is supported by the 1st protrusion part 13 without using a cantilever structure. With such a structure, the strength of the joint portion 3 can be ensured.

また、ピストンリング１では、第２の突出部１５の先端面１５ａは、内周面２ｃ側を向く凹状の湾曲面となっており、第２の受け部１６の先端面１６ａは、外周面２ｄ側を向く凸状の湾曲面となっている。ピストンの外周面にピストンリング１を装着したときに、合口部３の厚さ方向に流れるガスは、ピストンリング１の径方向に沿って内周面２ｃ側から外周面２ｄ側に向かう方向に流れる。このとき、第２の突出部１５及び第２の受け部１６の先端面１５ａ，１６ａが上述した湾曲面となっているので、第２の突出部１５と第２の受け部１６との間に形成される厚さ方向のガス流路は、外周面２ｄ側に向かうにしたがってピストンリング１の径方向から周方向へと徐々に変化する。このように内周面２ｃ側では、元々のガス流路の向きと、先端面１５ａ，１６ａ間に形成されるガス流路の向きとが一致するため、ガスの滞留が抑制される。したがって、ガスの滞留の抑制により合口端部１１，１２にヒートスポットが発生しにくくなり、合口部３の摩耗及び破損が抑制される。 In the piston ring 1, the tip surface 15a of the second protrusion 15 is a concave curved surface facing the inner peripheral surface 2c, and the tip surface 16a of the second receiving portion 16 is the outer peripheral surface 2d. It is a convex curved surface facing the side. When the piston ring 1 is mounted on the outer peripheral surface of the piston, the gas flowing in the thickness direction of the joint portion 3 flows along the radial direction of the piston ring 1 in the direction from the inner peripheral surface 2c side to the outer peripheral surface 2d side. . At this time, the tip surfaces 15a and 16a of the second projecting portion 15 and the second receiving portion 16 are the curved surfaces described above, and therefore, between the second projecting portion 15 and the second receiving portion 16. The formed gas flow passage in the thickness direction gradually changes from the radial direction of the piston ring 1 to the circumferential direction toward the outer peripheral surface 2d side. Thus, on the inner peripheral surface 2c side, the original direction of the gas flow path coincides with the direction of the gas flow path formed between the front end faces 15a and 16a, so that gas retention is suppressed. Therefore, heat spots are less likely to be generated at the abutting end portions 11 and 12 due to suppression of gas retention, and wear and breakage of the abutting portion 3 are suppressed.

本発明は、上記実施形態に限られるものではない。例えば上記実施形態では、本体部２を金属又は合金によって形成することを例示しているが、加工容易性をより重視する場合には、合成樹脂等によってピストンリング１の本体部２を形成してもよい。 The present invention is not limited to the above embodiment. For example, in the above embodiment, the main body 2 is formed of a metal or an alloy. However, when the workability is more important, the main body 2 of the piston ring 1 is formed of a synthetic resin or the like. Also good.

また、上記実施形態では、先鋭部分２１が第２の突出部１５の外周面２ｄ側に設けられているが、例えば図６（ａ）に示す第１変形例のように、先鋭部分２１が内周面２ｃ側に設けられてもよい。この場合、第２の突出部１５の先端面１５ａは、外周面２ｄ側を向く凹状の湾曲面となり、第２の受け部１６の先端面１６ａは、内周面２ｃ側を向く凸状の湾曲面となる。このような第１変形例においても、上記実施形態と同様に、合口部３の加工容易性とシール性とを良好に確保できる。また、ピストンの外周面にピストンリング１を装着したときに、先鋭部分２１がシリンダに衝突しなくなり、合口部３の摩耗及び破損が抑制される。加えて、合口部３の厚さ方向に流れるガスは、ピストンリング１の径方向に沿って内周面２ｃ側から外周面２ｄ側に向かう方向に流れる。このとき、第２の突出部１５及び第２の受け部１６の先端面１５ａ，１６ａが上述した湾曲面となっているので、第２の突出部１５と第２の受け部１６との間に形成される厚さ方向のガス流路は、外周面２ｄ側に向かうにしたがってピストンリング１の周方向から径方向へと徐々に変化する。このように内周面２ｃ側では、元々のガス流路の向きと、先端面１５ａ，１６ａ間に形成されるガス流路の向きとが大きくずれるため、ガスが側面２ｂ側の合口部３に入りにくくなる。したがって、先端面１５ａ，１６ａ間に形成されるガス流路を介したガスの抜けを一層確実に抑制できる。 Moreover, in the said embodiment, although the sharp part 21 is provided in the outer peripheral surface 2d side of the 2nd protrusion part 15, for example, like the 1st modification shown to Fig.6 (a), the sharp part 21 is an inside. You may provide in the surrounding surface 2c side. In this case, the tip surface 15a of the second protrusion 15 is a concave curved surface facing the outer peripheral surface 2d, and the tip surface 16a of the second receiving portion 16 is a convex curve facing the inner peripheral surface 2c. It becomes a surface. Also in such a 1st modification, the processability and sealing performance of the abutment part 3 can be ensured satisfactorily as in the above embodiment. Further, when the piston ring 1 is mounted on the outer peripheral surface of the piston, the sharpened portion 21 does not collide with the cylinder, and wear and breakage of the joint portion 3 are suppressed. In addition, the gas flowing in the thickness direction of the joint portion 3 flows in the direction from the inner peripheral surface 2c side to the outer peripheral surface 2d side along the radial direction of the piston ring 1. At this time, the tip surfaces 15a and 16a of the second projecting portion 15 and the second receiving portion 16 are the curved surfaces described above, and therefore, between the second projecting portion 15 and the second receiving portion 16. The formed gas flow passage in the thickness direction gradually changes from the circumferential direction of the piston ring 1 to the radial direction toward the outer peripheral surface 2d side. In this way, on the inner peripheral surface 2c side, the original direction of the gas flow path and the direction of the gas flow path formed between the front end faces 15a and 16a are greatly deviated, so that the gas enters the abutment portion 3 on the side surface 2b side. It becomes difficult to enter. Therefore, the escape of gas through the gas flow path formed between the tip surfaces 15a and 16a can be suppressed more reliably.

図６（ｂ）に示す第２変形例のように、例えば先鋭部分２１が第２の受け部１６に設けられると共に、先鋭部分２１が第２の受け部１６の外周面２ｄ側に設けられてもよい。この場合、第２の突出部１５の先端面１５ａは、外周面２ｄ側を向く凸状の湾曲面となり、第２の受け部１６の先端面１６ａは、内周面２ｃ側を向く凹状の湾曲面となる。第２変形例の場合、上記実施形態と同様に、合口部３の加工容易性とシール性とを良好に確保できると共に、合口端部１１，１２にヒートスポットが発生しにくくなり、合口部３の摩耗及び破損が抑制される。 6B, for example, the sharpened portion 21 is provided on the second receiving portion 16, and the sharpened portion 21 is provided on the outer peripheral surface 2d side of the second receiving portion 16. As shown in FIG. Also good. In this case, the tip surface 15a of the second protrusion 15 is a convex curved surface facing the outer peripheral surface 2d, and the tip surface 16a of the second receiving portion 16 is a concave curve facing the inner peripheral surface 2c. It becomes a surface. In the case of the second modified example, as in the above embodiment, the processability and sealing performance of the joint portion 3 can be ensured satisfactorily, and heat spots are less likely to occur at the joint end portions 11 and 12, and the joint portion 3 Wear and breakage of the steel are suppressed.

図６（ｃ）に示す第３変形例のように、例えば先鋭部分２１が第２の受け部１６に設けられると共に、先鋭部分２１が第２の受け部１６の内周面２ｃ側に設けられてもよい。この場合、第２の突出部１５の先端面１５ａは、内周面２ｃ側を向く凸状の湾曲面となり、第２の受け部１６の先端面１６ａは、外周面２ｄ側を向く凹状の湾曲面となる。第３変形例の場合、上記第１変形例と同様に、合口部３の加工容易性を良好に確保でき、先鋭部分２１がシリンダに衝突しなくなることで合口部３の摩耗及び破損が抑制されると共に、ガスが側面２ｂ側の合口部３に入りにくくなることでシール性をより良好に確保できる。 6C, for example, the sharpened portion 21 is provided on the second receiving portion 16, and the sharpened portion 21 is provided on the inner peripheral surface 2c side of the second receiving portion 16. As shown in FIG. May be. In this case, the distal end surface 15a of the second protrusion 15 is a convex curved surface facing the inner peripheral surface 2c, and the distal end surface 16a of the second receiving portion 16 is a concave curved surface facing the outer peripheral surface 2d. It becomes a surface. In the case of the third modified example, similarly to the first modified example, the workability of the joint portion 3 can be ensured satisfactorily, and the sharp portion 21 does not collide with the cylinder, so that wear and breakage of the joint portion 3 are suppressed. In addition, since the gas is less likely to enter the joint portion 3 on the side surface 2b side, it is possible to secure better sealing performance.

また、上記実施形態では、側面２ｂ側から見た先端面１５ａ，１６ａは、弧状となっているが、例えば図７に示すように、第４変形例では、側面２ｂ側から見た先端面１５ａ，１６ａを楕円形状の一部としてもよい。もしくは、側面２ｂ側から見た先端面１５ａ，１６ａを、インボリュート曲線を描くように湾曲してもよい。これらの場合、第２の突出部１５と第２の受け部１６との間に形成される厚さ方向のガス流路がより長くなる。なお、インボリュート曲線とは、該曲線の法線が常に一つの定円に接することにより描かれる曲線である。側面２ｂ側から見た先端面１５ａ，１６ａがインボリュート曲線を描くように湾曲する場合、例えば側面２ｂ側から見た先端面１６ａの曲率半径は、内周面２ｃ側から外周面２ｄ側にかけて連続的に増加する。また、側面２ｂ側から見た先端面１５ａ，１６ａを、円形状又は真円形状の一部としてもよい。第４変形例にて示された、側面２ｂ側から見た先端面１５ａ，１６ａの形状は、上記実施形態、第１〜第３変形例、及び後述する第５〜第８変形例に適用できる。 Moreover, in the said embodiment, although the front end surfaces 15a and 16a seen from the side surface 2b side are arc-shaped, for example, as shown in FIG. 7, in the 4th modification, the front end surface 15a seen from the side surface 2b side. 16a may be part of an elliptical shape. Or you may curve the front end surfaces 15a and 16a seen from the side surface 2b side so that an involute curve may be drawn. In these cases, the gas flow path in the thickness direction formed between the second projecting portion 15 and the second receiving portion 16 becomes longer. An involute curve is a curve drawn when the normal line of the curve always touches one constant circle. When the distal end surfaces 15a and 16a viewed from the side surface 2b are curved so as to draw an involute curve, for example, the radius of curvature of the distal end surface 16a viewed from the side surface 2b side is continuous from the inner peripheral surface 2c side to the outer peripheral surface 2d side. To increase. Moreover, it is good also considering the front end surfaces 15a and 16a seen from the side surface 2b side as a part of circular shape or perfect circle shape. The shapes of the tip surfaces 15a and 16a viewed from the side surface 2b shown in the fourth modification can be applied to the above-described embodiment, first to third modifications, and fifth to eighth modifications described later. .

また、上記実施形態では、側面２ｂ側から見た先端面１５ａ，１６ａの曲率半径は同一となっているが、これらの曲率半径は互いに異なってもよい。例えば図８に示すように、第５変形例では、第２の突出部１５の先端面１５ａは、外周面２ｄ側を向く凸状の湾曲面となり、第２の受け部１６の先端面１６ａは、内周面２ｃ側を向く凹状の湾曲面となると共に、側面２ｂ側から見て、第２の突出部１５の先端面１５ａの曲率半径Ｒ１は、第２の受け部１６の先端面１６ａの曲率半径Ｒ２よりも小さくなっている。また、曲率半径Ｒ２を描く中心点Ｐ２は、曲率半径Ｒ１を描く中心点Ｐ１よりも内周面２ｃ側に位置している。この場合、第２の突出部１５の先端面１５ａ、及び第２の受け部１６の先端面１６ａは、一方の合口端部１１と他方の合口端部１２とを正対させたときに、側面２ｂ側から見た第２の突出部１５と第２の受け部１６との隙間が内周面２ｃ側から外周面２ｄ側に向かって狭くなるように湾曲している。例えば、内周面２ｃにおける先端面１５ａ，１６ａ同士の隙間の距離ｄ１は、外周面２ｄにおける先端面１５ａ，１６ａ同士の隙間の距離ｄ２よりも大きくなる。ピストンの外周面にピストンリング１を装着したときに、ピストンリング１の合口部３において厚さ方向に流れるガスは、内周面２ｃ側から外周面２ｄ側に向かって流れる。したがって、上記隙間が内周面２ｃ側から外周面２ｄ側に向かって狭くなるように先端面１５ａ，１６ａが湾曲していることにより、上記ガスの抜けを一層確実に抑制できる。第５変形例にて示された、一方の合口端部１１と他方の合口端部１２とを正対させたときの第２の突出部１５の先端面１５ａと第２の受け部１６の先端面１６ａとの関係は、上記実施形態、第１〜第４変形例、及び後述する第６〜第８変形例に適用できる。 Moreover, in the said embodiment, although the curvature radius of the front end surfaces 15a and 16a seen from the side surface 2b side is the same, these curvature radii may mutually differ. For example, as shown in FIG. 8, in the fifth modification, the tip surface 15a of the second projecting portion 15 is a convex curved surface facing the outer peripheral surface 2d side, and the tip surface 16a of the second receiving portion 16 is The curvature radius R1 of the distal end surface 15a of the second projecting portion 15 is the radius of the distal end surface 16a of the second receiving portion 16 as viewed from the side surface 2b side. It is smaller than the curvature radius R2. Further, the center point P2 that draws the curvature radius R2 is located closer to the inner peripheral surface 2c than the center point P1 that draws the curvature radius R1. In this case, the front end surface 15a of the second projecting portion 15 and the front end surface 16a of the second receiving portion 16 are side surfaces when the one end portion 11 and the other end portion 12 face each other. The gap between the second projecting portion 15 and the second receiving portion 16 as viewed from the 2b side is curved so as to become narrower from the inner peripheral surface 2c side toward the outer peripheral surface 2d side. For example, the distance d1 between the front end surfaces 15a and 16a on the inner peripheral surface 2c is larger than the distance d2 between the front end surfaces 15a and 16a on the outer peripheral surface 2d. When the piston ring 1 is mounted on the outer peripheral surface of the piston, the gas flowing in the thickness direction at the joint portion 3 of the piston ring 1 flows from the inner peripheral surface 2c side toward the outer peripheral surface 2d side. Therefore, the end faces 15a and 16a are curved so that the gap becomes narrower from the inner peripheral surface 2c side to the outer peripheral surface 2d side, whereby the gas escape can be suppressed more reliably. The tip surface 15a of the second projecting portion 15 and the tip of the second receiving portion 16 when the one abutment end portion 11 and the other abutment end portion 12 face each other as shown in the fifth modification example The relationship with the surface 16a can be applied to the above-described embodiment, first to fourth modifications, and sixth to eighth modifications described later.

また、上記実施形態では、第１の突出部１３及び第２の突出部１５の断面形状がいずれも長方形状となっているが、第６変形例として、例えば第２の突出部１５を図９に示すような形状としてもよい。具体的には、第１の突出部１３及び第２の受け部１６を断面長方形状のまま維持する一方、第２の突出部１５の幅が先端側に向かって狭くなるように、第２の突出部１５における第１の突出部１３との合わせ面１５ｂを、第１の突出部１３における第２の突出部１５との合わせ面１３ｂに対して傾斜させてもよい。この場合、クランクＣ１の長さをより拡張できるので、クランクＣ１での圧力損失が大きくなり、ピストンリング１の幅方向へのガスの抜けを一層確実に抑制できる。加えて、第２の突出部１５の基端部がより肉厚になるため、第２の突出部１５の強度をより確保できる。 Moreover, in the said embodiment, although the cross-sectional shape of the 1st protrusion part 13 and the 2nd protrusion part 15 is all rectangular shape, the 2nd protrusion part 15 is shown in FIG. It is good also as a shape as shown in. Specifically, while maintaining the first protruding portion 13 and the second receiving portion 16 in a rectangular cross-section, the second protruding portion 15 is narrowed toward the distal end side so that the second protruding portion 15 becomes narrower. The mating surface 15 b of the projecting portion 15 with the first projecting portion 13 may be inclined with respect to the mating surface 13 b of the first projecting portion 13 with the second projecting portion 15. In this case, since the length of the crank C1 can be further expanded, the pressure loss in the crank C1 is increased, and the escape of gas in the width direction of the piston ring 1 can be further reliably suppressed. In addition, since the base end part of the 2nd protrusion part 15 becomes thicker, the intensity | strength of the 2nd protrusion part 15 can be ensured more.

また、図９の例では、第１の受け部１４の先端面１４ａが、第１の突出部１３の先端面１３ａに対して傾斜していると共に、第２の突出部１５の先端面１５ａが、第２の受け部１６の先端面１６ａに対して傾斜している。これにより、先端面１３ａ，１４ａ同士の接触を回避でき、第１の突出部１３の摩耗を抑制できる。同様に、先端面１５ａ，１６ａ同士の接触を回避でき、第２の突出部１５の摩耗を抑制できる。第６変形例にて示された、第２の突出部１５の形状は、上記実施形態、第１〜第５変形例、及び後述する第８変形例に適用できる。 In the example of FIG. 9, the tip surface 14 a of the first receiving portion 14 is inclined with respect to the tip surface 13 a of the first projecting portion 13, and the tip surface 15 a of the second projecting portion 15 is The second receiving portion 16 is inclined with respect to the distal end surface 16a. Thereby, the contact of tip surface 13a, 14a can be avoided, and abrasion of the 1st protrusion part 13 can be suppressed. Similarly, contact between the tip surfaces 15a and 16a can be avoided, and wear of the second protrusion 15 can be suppressed. The shape of the 2nd protrusion part 15 shown by the 6th modification is applicable to the said embodiment, the 1st-5th modification, and the 8th modification mentioned later.

さらに、図９の例では、第１の突出部１３及び第２の受け部１６を断面長方形状としているが、第７変形例として、例えば図１０に示すように、第１の突出部１３の先端面１３ａ、第１の受け部１４の先端面１４ａ、第１の突出部１３における第２の突出部１５との合わせ面１３ｂ、第２の突出部１５における第１の突出部１３との合わせ面１５ｂ、第２の突出部１５の先端面１５ａ、及び第２の受け部１６の先端面１６ａを、それぞれ側面２ａ，２ｂに対して傾斜させてもよい。 Furthermore, in the example of FIG. 9, the first protrusion 13 and the second receiving part 16 are rectangular in cross section. However, as a seventh modification, for example, as shown in FIG. The tip surface 13a, the tip surface 14a of the first receiving portion 14, the mating surface 13b of the first projecting portion 13 with the second projecting portion 15, and the mating of the second projecting portion 15 with the first projecting portion 13 You may incline the surface 15b, the front end surface 15a of the 2nd protrusion part 15, and the front end surface 16a of the 2nd receiving part 16 with respect to the side surfaces 2a and 2b, respectively.

この場合、クランクＣ１の長さを更に拡張できるので、ピストンリング１の幅方向へのガスの抜けを一層確実に抑制できる。また、第１の突出部１３の基端部がより肉厚になるため、第１の突出部１３の強度をより確保できる。なお、第１の突出部１３は、ピストンリング１の使用時において幅方向にガス圧のバランスが取れるため、第２の突出部１５に比べて強度が多少小さくてもよい。また、図１０において、先端面１３ａ，１４ａ同士及び先端面１５ａ，１６ａ同士は、いずれも非平行であることが好ましい。こうすると、先端面１３ａ，１４ａ同士の接触及び先端面１５ａ，１６ａ同士の接触を回避でき、第１の突出部１３及び第２の突出部１５の摩耗を回避できる。第７変形例にて示された、第１の突出部１３の先端面１３ａ，第１の受け部１４の先端面１４ａ、第１の突出部１３における第２の突出部１５との合わせ面１３ｂ、第２の突出部１５における第１の突出部１３との合わせ面１５ｂ、第２の突出部１５の先端面１５ａ、及び第２の受け部１６の先端面１６ａの関係は、上記実施形態、第１〜第５変形例、及び後述する第８変形例に適用できる。 In this case, since the length of the crank C1 can be further expanded, the escape of gas in the width direction of the piston ring 1 can be more reliably suppressed. Moreover, since the base end part of the 1st protrusion part 13 becomes thicker, the intensity | strength of the 1st protrusion part 13 can be ensured more. The first protrusion 13 may have a slightly lower strength than the second protrusion 15 because the gas pressure is balanced in the width direction when the piston ring 1 is used. In addition, in FIG. 10, it is preferable that the tip surfaces 13a and 14a and the tip surfaces 15a and 16a are all non-parallel. If it carries out like this, the contact of tip surfaces 13a and 14a and the contact of tip surfaces 15a and 16a can be avoided, and wear of the 1st projection part 13 and the 2nd projection part 15 can be avoided. The mating surface 13b of the first projecting portion 13 with the tip surface 13a of the first projecting portion 13, the tip surface 14a of the first receiving portion 14, and the mating surface 13b of the first projecting portion 13 with the second projecting portion 15 shown in the seventh modification. The relationship between the mating surface 15b of the second projecting portion 15 with the first projecting portion 13, the distal end surface 15a of the second projecting portion 15, and the distal end surface 16a of the second receiving portion 16 is the same as in the above embodiment, The present invention can be applied to first to fifth modifications and an eighth modification described later.

また、上記実施形態及び第１〜第７変形例では、側面２ａ側に位置する第１の突出部１３及び第１の受け部１４はストレート合口を形成しているが、本発明ではこれに限定されない。例えば、第１の突出部１３及び第１の受け部１４は斜め合口又は段付き合口であってもよい。もしくは、第１の突出部１３及び第１の受け部１４は、第２の突出部１５及び第２の受け部１６と同様に、第１の突出部１３の先端面１３ａが凸状及び凹状の一方をなす湾曲面となっており、第１の受け部１４の先端面１４ａが凸状及び凹状の他方をなすと共に、第１の突出部１３の先端面１３ａの湾曲形状に対応する湾曲面となってもよい。この場合、先端面１３ａが凹状の湾曲面でもよく、凸状の湾曲面でもよい。また、先端面１３ａは内周面２ｃ側を向いてもよく、外周面２ｄ側を向いてもよい。第１の突出部１３の先端面１３ａ、及び第１の受け部１４の先端面１４ａは、一方の合口端部１１と他方の合口端部１２とを正対させたときに、側面２ａ側から見た第１の突出部１３と第１の受け部１４との隙間が一定になるように湾曲してもよく、内周面２ｃ側から外周面２ｄ側に向かって狭くなるように湾曲してもよい。 Moreover, in the said embodiment and the 1st-7th modification, although the 1st protrusion part 13 and the 1st receiving part 14 which are located in the side surface 2a side form the straight joint, it is limited to this in this invention Not. For example, the first projecting portion 13 and the first receiving portion 14 may be an oblique joint or a stepped joint. Alternatively, the first projecting portion 13 and the first receiving portion 14 are similar to the second projecting portion 15 and the second receiving portion 16 in that the front end surface 13a of the first projecting portion 13 is convex and concave. And a curved surface corresponding to the curved shape of the distal end surface 13a of the first protrusion 13 and the distal end surface 14a of the first receiving portion 14 is the other of the convex shape and the concave shape. It may be. In this case, the distal end surface 13a may be a concave curved surface or a convex curved surface. Moreover, the front end surface 13a may face the inner peripheral surface 2c side, and may face the outer peripheral surface 2d side. The front end surface 13a of the first projecting portion 13 and the front end surface 14a of the first receiving portion 14 are arranged from the side surface 2a side when the one abutment end portion 11 and the other abutment end portion 12 face each other. It may be curved so that the gap between the first protruding portion 13 and the first receiving portion 14 as seen is constant, or curved so as to become narrower from the inner peripheral surface 2c side toward the outer peripheral surface 2d side. Also good.

１…ピストンリング、２…本体部、２ａ…側面（一側面）、２ｂ…側面（他側面）、２ｃ…内周面、２ｄ…外周面、３…合口部、１１…一方の合口端部、１２…他方の合口端部、１３…第１の突出部、１３ａ…先端面、１３ｂ…合わせ面、１４…第１の受け部、１４ａ…先端面、１５…第２の突出部、１５ａ…先端面、１５ｂ…合わせ面、１６…第２の受け部、１６ａ…先端面、２１…先鋭部分、Ｃ１…クランク、Ｐ１、Ｐ２…中心点。 DESCRIPTION OF SYMBOLS 1 ... Piston ring, 2 ... Main-body part, 2a ... Side surface (one side surface), 2b ... Side surface (other side surface), 2c ... Inner peripheral surface, 2d ... Outer peripheral surface, 3 ... Joint part, 11 ... One joint end part, DESCRIPTION OF SYMBOLS 12 ... Other joint edge part, 13 ... 1st protrusion part, 13a ... Tip surface, 13b ... Mating surface, 14 ... 1st receiving part, 14a ... Tip surface, 15 ... 2nd protrusion part, 15a ... Tip Surface, 15b ... mating surface, 16 ... second receiving portion, 16a ... tip surface, 21 ... sharpened portion, C1 ... crank, P1, P2 ... center point.

Claims

A piston ring having an annular main body portion having an inner peripheral surface and an outer peripheral surface facing each other, and a joint portion formed in the main body portion,
In the joint part,
A first protrusion that protrudes from one abutment end toward the other abutment end and a first protrusion that receives the first protrusion at the other abutment end on one side of the main body. And a receiving part,
On the other side of the main body portion, a second projecting portion projecting from the other joint end portion toward the one joint end portion and the second projecting portion at the one joint end portion are received. A second receiver is provided,
The tip surface of the second protrusion is a curved surface that forms one of a convex shape and a concave shape,
The distal end surface of the second receiving portion forms the other of a convex shape and a concave shape, and is a curved surface corresponding to the curved shape of the distal end surface of the second projecting portion.
piston ring.

The tip surface of the second protrusion is a concave curved surface facing the inner peripheral surface side,
The piston ring according to claim 1, wherein the tip surface of the second receiving portion is a convex curved surface facing the outer peripheral surface.

The tip surface of the second protrusion is a convex curved surface facing the outer peripheral surface side,
The piston ring according to claim 1, wherein the tip surface of the second receiving portion is a concave curved surface facing the inner peripheral surface.

The tip surface of the second protrusion is a concave curved surface facing the outer peripheral surface side,
The piston ring according to claim 1, wherein the tip surface of the second receiving portion is a convex curved surface facing the inner peripheral surface.

The tip surface of the second protrusion is a convex curved surface facing the inner peripheral surface,
The piston ring according to claim 1, wherein the tip surface of the second receiving portion is a concave curved surface facing the outer peripheral surface.

The front end surface of the second projecting portion and the front end surface of the second receiving portion are arranged on the one side surface side when the one abutment end and the other abutment end are opposed to each other. 6. The device according to claim 1, wherein a gap between the second projecting portion and the second receiving portion viewed from the side is curved so as to become narrower from the inner peripheral surface side toward the outer peripheral surface side. The piston ring according to one item.

The mating surface of the second projecting portion with the first projecting portion is a second projecting portion of the first projecting portion so that the width of the second projecting portion becomes narrower toward the tip side. The piston ring as described in any one of Claims 1-6 which inclines with respect to the mating surface.

The piston ring as described in any one of Claims 1-7 in which the front end surface of the said 1st receiving part inclines with respect to the front end surface of the said 1st protrusion part.

The piston ring according to any one of claims 1 to 8, wherein the tip surface of the second projecting portion is inclined with respect to the tip surface of the second receiving portion.

The said main-body part is a piston ring as described in any one of Claims 1-9 currently formed with the metal or the alloy.