Multi-piece oil scraper ring with reduced friction

A multi-piece piston ring, comprising:

• an upper scraper ring having axially upper and lower flank surfaces, radially outer scraping surface and radially inner spring contact surface;
• a lower spring support ring having an axially upper flank surface;
• an expander spring having axially upper and lower sides thereof which, in use, are adapted to abut a respective lower one of the flank surfaces of the upper scraper ring and the upper flank surface of the lower support ring;
• wherein the lower spring support ring has an L-shaped cross-section with a radial leg thereof extending in a radial direction and parallel to the upper scraper ring and an axial leg thereof extending in an axial direction on an inside thereof toward the expander spring;
• wherein, when viewed in the radial direction, an outer surface of the axial leg forms a spring contact surface;
• wherein the expander spring includes scraper ring contact projections protruding upwards on an inner spring side, and including an edge provided on a bottom of the inner spring side which can abut against the axial leg of the lower spring support ring;
• and
• wherein no portion of the expander spring extends below the axially upper flank surface of the lower spring support ring.

A multi-piece piston ring, comprising:

• an upper scraper ring having axially upper and lower flank surfaces, radially outer scraping surface and radially inner spring contact surface;
• a lower spring support ring having an axially upper flank surface;
• an expander spring having axially upper and lower sides thereof which, in use, are adapted to abut a respective lower one of the flank surfaces of the upper scraper ring and the upper flank surface of the lower support ring;
• wherein the lower spring support ring has an L-shaped cross-section with a radial leg thereof extending in a radial direction and parallel to the upper scraper ring and an axial leg thereof extending in an axial direction on an inside thereof toward the expander spring;
• wherein, when viewed in the radial direction, an outer surface of the axial leg forms a spring contact surface;
• wherein the expander spring includes scraper ring contact projections protruding upwards on an inner spring side, and including an edge provided on a bottom of the inner spring side which can abut against the axial leg of the lower spring support ring;
• and
• wherein the expander comprises a strip bent to a U-shape with an open side of the U-shape facing toward an inside diameter of the expander ring.