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US 6,205,908 B1Granted
Piston equipped with piston ring
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsTeruo Kumai, Michio Okamoto
Life of this patent
Estimating the term…
Abstract
The present invention aims at reducing the amount of oil consumption in a piston using a piston ring continuously formed of resin without being provided with an abutment. A stepped portion is formed on a third land, which is located below a second ring having a construction wherein an outer ring continuously formed of polyimide without being provided with an abutment is pressed against a cylinder wall by a coil expander via an inner ring continuously formed of PTFE without being provided with an abutment. Oil spill ports are provided so as to allow communication between the stepped portion and an inner wall of the piston.
Claims11
A piston comprising:
- a piston ring structural body including a ring that is continuously formed of resin without being provided with an abutment and slides against a cylinder wall;
- a ring groove into which said piston ring structural body is fitted;
- and
- a land portion that is formed on an outer circumference of said piston on a side of a crank case with respect to said ring groove and having at least a portion closer to said cylinder wall than a bottom portion of said ring groove,
- wherein said land portion has formed therethrough an oil return port that allows communication between a cylinder-side face of said land portion and an inner space defined by an inner wall of said piston,
- wherein said land portion defines an oil transportation mechanism that transports oil which has reached said land portion to said oil return port when said piston moves toward said crank case,
- wherein said oil transportation mechanism has a first portion that is formed on said land portion and located nearest to said cylinder wall and a second portion that is formed on a side of said crank case relative to said first portion of said land portion and located farther from said cylinder wall than said first portion is from said cylinder wall, and
- wherein said oil return port allows communication between the cylinder-side face of said second portion and the inner space piston.
5 more elements
A piston comprising:
- a piston ring structural body including a ring that is continuously formed of resin without being provided with an abutment and slides against a cylinder wall, including:
- an outer ring continuously formed of a resinous material without being provided with an abutment;
- an inner ring continuously formed with resinous material without being provided with
- an abutment;
- and
- a metal coil expander for pressing said inner ring radially outwards;
- a ring groove into which said piston ring structural body is fitted;
- and
- a land portion that is formed on an outer circumference of said piston on a side of a crank case with respect to said ring groove and having at least a portion closer to said cylinder wall than a bottom portion of said ring groove,
- wherein said land portion has formed therethrough an oil return port that allows communication between a cylinder-side face of said land portion and an inner space defined by an inner wall of said piston,
- wherein said land portion defines an oil transportation mechanism that transports oil which has reached said land portion to said oil return port when said piston moves toward said crank case,
- wherein said outer ring is made of polyimide and said inner ring is made of polytetrafluoroethylene.
9 more elements
A piston comprising:
- a piston ring structural body including a ring that is continuously formed of resin without being provided with an abutment and slides against a cylinder wall, including:
- an outer ring made of a metal material and provided with an abutment;
- an inner ring made of a metal material and provided with an abutment;
- and
- a metal coil expander for pressing said inner ring radially outwards;
- a ring groove into which said piston ring structural body is fitted;
- and
- a land portion that is formed on an outer circumference of said piston on a side of a crank case with respect to said ring groove and having at least a portion closer to said cylinder wall than a bottom portion of said ring groove,
- wherein said land portion has formed therethrough an oil return port that allows communication between a cylinder-side face of said land portion and an inner space defined by an inner wall of said piston,
- wherein said land portion defines an oil transportation mechanism that transports oil which has reached said land portion to said oil return port when said piston moves toward said crank case.
7 more elements
Dependencies are inferred from the claim text.