Abstract: An oil control ring comprises: an oil ring having a pair of land parts arranged in a sliding direction and connected to each other by a web part; and a coil expander that biases the oil ring toward the outer circumferential side in the radial direction. The web part of the oil ring is provided with a plurality of window holes. In the axial cross-sectional view of the largest opening portion of the window hole in the axial direction of the oil ring, a width H1 in the sliding direction of the oil ring and a length L1 of a combustion chamber-side non-window hole part, which excludes the window hole, in the outer circumferential surface of the web part, satisfy the condition of 0.15>L1/H1?0.

Abstract: An injection molding apparatus includes a vessel, mold, pusher, and thrust providing section. The vessel stores a molding material and has a nozzle hole which is formed in the bottom portion to inject the molding material and a first seal surface formed around the nozzle hole. The mold is made up of stacked members stacked on the lower side of the vessel and is filled with the molding material injected from the vessel. The mold has a sprue communicating with the nozzle hole and a second seal surface formed around the sprue. The stacked members respectively have third seal surfaces at portions where the members are in contact with each other. The pusher pressurizes the molding material in the vessel. The thrust providing section provides a thrust to the pusher to pressurize one of the pusher and the mold through the molding material in the vessel.

Abstract: An injection molding apparatus includes a vessel, mold, pusher, and thrust providing section. The vessel stores a molding material and has a nozzle hole which is formed in the bottom portion to inject the molding material and a first seal surface formed around the nozzle hole. The mold is made up of stacked members stacked on the lower side of the vessel and is filled with the molding material injected from the vessel. The mold has a sprue communicating with the nozzle hole and a second seal surface formed around the sprue. The stacked members respectively have third seal surfaces at portions where the members are in contact with each other. The pusher pressurizes the molding material in the vessel. The thrust providing section provides a thrust to the pusher to pressurize one of the pusher and the mold through the molding material in the vessel.