JP2012127203A - Piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston ring reducing the oil consumption.SOLUTION: A piston ring 5 is a resin-made ring having an abutment 11. A tapered surface 7 and an axially parallel surface 8 below the tapered surface 7 are provided on an outer circumferential surface 6. A plurality of radial grooves 10 penetrating the inner peripheral and the outer circumferential sides are formed in a lower surface 9 with a spacing in the circumferential direction. The width W in the axial direction of the axially parallel surface 8 is larger than the depth D in the axial direction of the radial grooves 10, and the ring abutment 11 is closed when fitting a cylinder 1. An undercut part is formed in a lower part of the outer circumference, and the width in the axial direction of the undercut part is preferably larger than the depth in the axial direction of the grooves.

Description

  The present invention relates to a resin piston ring.

  Conventionally, there is a problem that oil consumption increases due to oil flowing into the combustion chamber side from the joint gap of the second ring with respect to oil consumption due to suction at the negative pressure of the intake pipe. In addition, the pressure in the second land portion of the piston may become higher than the pressure in the combustion chamber when the piston descends during the combustion stroke, and the oil adhering to the cylinder wall is raised to the combustion chamber side, increasing oil consumption. There was a problem.

  Patent Document 1 describes a piston ring for an internal combustion engine having a two-piece structure of a resin ring without a joint and a metal ring with a joint. For oil consumption due to suction when the intake pipe is under negative pressure, oil consumption can be reduced because there is no joint in the resin ring. Patent document 2 describes forming a groove in the lower surface of the ring. By releasing the pressure in the second land portion through the groove, the oil remaining above the top ring flows to the crankcase side due to the pressure in the combustion chamber, thereby reducing oil consumption.

JP 2002-54499 A Japanese Utility Model Publication No. 56-132351

  However, in Patent Document 1, since a resin ring without a joint is used, the pressure of the second land portion becomes higher than the combustion chamber when the piston descends during the combustion stroke, and the oil adhering to the cylinder wall is burned. It may raise to the room side and may increase oil consumption. Moreover, in patent document 2, since there is an abutment in the ring, there is a problem that oil flows from the abutment gap to the combustion chamber side during negative pressure, and oil consumption increases.

  An object of the present invention is to provide a piston ring that can reduce oil consumption.

  The present invention is a resin ring having an abutment, wherein the outer peripheral surface has a tapered surface and an axial parallel surface below the tapered surface, and the lower surface has a groove penetrating the inner peripheral side and the outer peripheral side in the circumferential direction. A plurality of the gaps are formed at intervals, the axial width of the axial parallel plane is larger than the axial depth of the groove, and the ring joint is closed when the cylinder is mounted.

  It is preferable that an undercut portion is provided at the lower outer periphery, and the axial width of the undercut portion is larger than the axial depth of the groove.

  The material is preferably thermoplastic polyimide, polyetheretherketone, polyphenylene sulfide, or polytetrafluoroethylene.

  According to the piston ring of the present invention, since the axial width of the axial parallel surface of the outer peripheral surface is larger than the axial depth of the groove on the lower surface, a seal with the cylinder inner peripheral surface can be secured. When the load is such that the pressure on the combustion chamber side becomes larger than the pressure on the crankcase side, the oil can be returned to the crankcase side through the groove on the lower surface of the ring. Since the ring is closed when the cylinder is mounted, oil consumption rising to the combustion chamber side when the combustion chamber becomes negative pressure can be reduced. If it has an undercut part in the outer periphery lower part of a ring, it will be easy to flow oil into a groove | channel.

It is a longitudinal cross-sectional view which shows one Embodiment of this invention and shows the state in which the piston equipped with the piston ring was inserted in the cylinder. It is a bottom view of the piston ring at the time of cylinder mounting. It is a longitudinal cross-sectional view which shows another embodiment of this invention, and shows the state in which the piston equipped with the piston ring was inserted in the cylinder. It is a bottom view of the piston ring at the time of cylinder mounting. FIG. 6 is a longitudinal sectional view showing a part of a piston ring according to still another embodiment of the present invention.

    Preferred embodiments of the present invention will be described below with reference to the drawings.

  1 and 2, a resin piston ring 5 is mounted in a ring groove 4 formed on the outer peripheral surface 3 of the piston 2 in the cylinder 1. The piston ring 5 is formed of a tapered surface 7 whose outer peripheral surface 6 decreases in thickness in the radial direction toward the upper side, and an axial parallel surface 8 provided continuously below the lower surface. Further, the piston ring 5 has a plurality of radial grooves 10 which penetrate the inner peripheral side and the outer peripheral side on the lower surface 9 at intervals in the circumferential direction. The axial width W of the axial parallel surface 8 of the piston ring 5 is larger than the axial depth D of the radial groove 10. The piston ring 5 has a joint 11, but the joint 11 is configured to be closed when the piston ring 5 is mounted in the cylinder 1. As the material of the piston ring 5, thermoplastic polyimide (PI), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE) is used.

  In the piston ring 5 of the present invention, the axial width W of the axial parallel surface 8 of the outer peripheral surface 6 is larger than the axial depth D of the radial groove 10 of the lower surface 9. Exists all around. Therefore, a seal with the inner peripheral surface 12 of the cylinder 1 can be ensured. When the piston ring 5 of the present invention is used as a second ring, the pressure of the second land portion 13 of the piston 2 is changed to the radial groove 10 of the lower surface 9 of the ring 2 under a load where the pressure on the combustion chamber side becomes larger than the pressure on the crankcase side. And the pressure of the second land portion 13 is prevented from increasing, and the oil can be returned to the crankcase side through the radial groove 10. Further, since the abutment 11 is closed when the cylinder 1 is attached to the piston ring 5, oil consumption rising to the combustion chamber side can be reduced even when the combustion chamber is at a negative pressure.

  3 and 4 show another embodiment of the present invention. This embodiment is different from the above embodiment in that the piston ring 5 has an undercut cross-sectional shape in which a lower portion of the outer peripheral surface 6 is cut out in a step shape. The axial width W <b> 1 of the undercut portion 14 is larger than the axial depth D of the radial groove 10 on the ring lower surface 9. If the undercut portion 14 is formed in this manner, the oil can easily flow into the radial groove 10 on the ring lower surface 9 and oil consumption can be reduced. The undercut shape is not limited to that shown in FIG. Another example is shown in FIG. The piston ring 5 in FIG. 5 has an undercut cross-sectional shape in which a lower portion of the outer peripheral surface 6 is cut out in a triangular shape.

  1 .... Cylinder, 2 .... Piston, 3 .... Piston outer surface, 4 .... Ring groove, 5 .... Piston ring, 6 .... Ring outer surface, 7 .... Taper surface, 8 .... Axial parallel surface, 9 .. Ring lower surface, 10 .. Groove, 11 .. Joint, 12 .. Cylinder inner peripheral surface, 13 .. Second land portion, 14 .. Undercut portion.

Claims (3)

  This ring is made of resin and has a tapered surface on the outer peripheral surface and an axially parallel surface on the lower side of the tapered surface, and a groove penetrating the inner peripheral side and the outer peripheral side on the lower surface. The piston ring is formed in a plurality, and the axial width of the axial parallel surface is larger than the axial depth of the groove, and the ring joint is closed when the cylinder is mounted.   The piston ring according to claim 1, further comprising an undercut portion at an outer peripheral lower portion, wherein an axial width of the undercut portion is larger than an axial depth of the groove.   The piston ring according to claim 1 or 2, wherein the material is thermoplastic polyimide, polyetheretherketone, polyphenylene sulfide, or polytetrafluoroethylene.

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