| 摘要 |
1294061 Pistons R L DEBIASSE 29 April 1971 12202/71 Heading F2T A piston 10 has a sealing assembly comprising a piston-ring 80 housed in a single annular recess 81 in the head 11; the recess comprising a groove 130, Fig. 8A, having upper and lower side walls 131 and 132 and a circumferential rebate 135 formed in the radially outer portion of the lower wall 132 and the ring 80 comprising a split compression ring 140 located with axial clearance in the groove 130 with its radially outer portion overhanging the rebate 135 and a split oil scraper ring 150 housed in the rebate. The ring 140 is urged radially outwards by a leaf-spring ring 145 and the ring 150 has an axial width not exceeding and preferably equal to that of the rebate. Main skirts 15, 16, each having an angular extent of less than 90 degrees, depend from the piston head in the thrust face regions and are interconnected by web means 20 integral with the head and having a thickened central portion 21 including a gudgeon pin boss 22 for a pin 26 by which the piston is connected to a connecting-rod 45. Diametrically opposite vestigial skirts 65 and 66 formed on the ends of ribs (67, 68, Fig. 5) on the head are disposed between the main skirts. The underside of the head 11 is formed with four concave recesses 92-95, Fig. 6. Oil drainage ports 90 are provided in slots 85, 86 above the main skirts 15, 16 and also in slots 87, 88 located between the slots 85, 86 and separated therefrom by unslotted portions 89. The main skirt faces 105, 106 are provided with axially spaced grooves 107 and the central portions 108, 109 of the faces conform to a surface of revolution 11 whilst the side portions 111-114 are ground to be spaced radially inwards of the surface 110. The faces 115, 116 of the skirts 65, 66 are similarly formed. The surface 110 is frusto-conical so that the surfaces 108, 109 of the main skirts taper upwardly over their length. |
