Two-piece oil-cooled piston

A two-piece piston comprising:

• a one-piece integral head section having a crown and being formed with an annular undercrown recess adjacent the periphery of the crown;
• a one-piece integral skirt section for assembly with the head section having an annular coolant-carrying tray in opposed spaced relation to the undercrown recess of the head section so as to form a coolant chamber substantially continuous about the periphery of the piston when the head and skirt sections are assembled together;
• the tray having an inner wall portion extending toward and spaced from the undercrown surface of the head section to provide a passage for controlling the flow of coolant exiting said tray toward the center portion of said undercrown surface;
• said skirt section being formed with at least one passage communicating with the tray for introducing coolant under force into said tray from a reservoir disposed beneath said piston;
• and
• the skirt section also being formed with an integral transverse bridge interconnecting diametrically opposed portions of the tray for conveying coolant from the tray toward the central undercrown surface of the head section.

A piston member for reciprocal movement in an internal combustion engine to move a crankshaft through a connecting rod comprising:

• (a) a head section having a crown and depending boss means for receiving a pin to connect said piston to said connecting rod, said head section being formed with an annular undercrown recess adjacent the periphery of the crown;
• (b) a support member being carried by said head section, said support member having an annular coolant-carrying tray in opposed spaced relationship to the undercrown recess of the head section, so as to form a coolant chamber substantially continuous about the periphery of the piston when the head section and support member are assembled together, the tray having an inner wall portion extending toward and spaced from the undercrown surface of the head section to provide passage for a coolant therethrough;
• (c) said piston member defining at least one inlet passage with the tray;
• and
• (d) a reservoir for coolant and means for forcing coolant from said reservoir through at least said one inlet passage into said tray.

A two-piece piston comprising:

• a one-piece integral head section having a crown and depending boss means, said boss means having a bore for receiving a pin, and the head section being formed with an annular undercrown recess adjacent the periphery of the crown;
• a one-piece integral skirt section for assembly with the head section, the skirt section having bores corresponding to and coaxial with the bore in the head section when the head and skirt sections are assembled together, and having an annular coolant-carrying tray in opposed spaced relation to the undercrown recess of the head section, so as to form a coolant chamber substantially continuous about the periphery of the piston when the head and skirt sections are assembled together, the tray having an inner lip extending toward and spaced from the undercrown surface of the head section;
• and
• adjacent peripheral portions of the head and skirt sections, when assembled in a cylinder bore, are spaced from each other forming an annular passage enabling draining coolant from the tray radially outwardly therefrom, and wherein at least one portion of the external cylindrical surface of the skirt section is relieved so as to form a passage communicating with the annular passage away from the head section.