Piston for swash plate type compressor, wherein head portion includes radially inner sliding projection connected to neck portion

A swash plate type compressor comprising:

• a cylinder block having a plurality of cylinder bores arranged along a circle;
• a rotary drive shaft having an axis aligned with a centerline of said circle;
• a swash plate rotated by said drive shaft;
• and
• a piston including a head portion slidably fitted in each of said cylinder bores, a neck portion slidably engaging said swash plate, and a connecting portion connecting said head and neck portions, said piston being reciprocated by rotation of said swash plate by said drive shaft,
• said head portion comprising a body portion having a circular shape in cross section, and an inner sliding projection extending toward said neck portion from a radially inner circumferential part of said body portion which corresponds to a radially inner portion of said cylinder block, said inner sliding projection having a sliding surface for sliding contact with an inner circumferential surface of said cylinder bore, said sliding surface being symmetrical with respect to a plane including a centerline of said piston and a centerline of said cylinder block,
• said connecting portion connecting said inner sliding projection and said neck portion, at said radially inner circumferential part of said body portion, and not connecting said head portion and said neck portion at a radially outer circumferential part of said body portion which corresponds to a radially outer portion of said cylinder block.

A swash plate type compressor comprising:

• a cylinder block having a plurality of cylinder bores arranged along a circle;
• a rotary drive shaft having an axis aligned with a centerline of said circle;
• a swash plate rotated by said drive shaft;
• and
• a piston including a head portion slidably fitted in each of said cylinder bores, a neck portion slidably engaging said swash plate, and a connecting portion connecting said head and neck portions, said piston being reciprocated by rotation of said swash plate by said drive shaft,
• said head portion comprises a body portion having a circular shape in cross section, and an inner sliding projection extending toward said neck portion from a radially inner circumferential part of said body portion which corresponds to a radially inner portion of said cylinder block, said inner sliding projection having a sliding surface for sliding contact with an inner circumferential surface of said cylinder bore, said inner sliding projection having at least one recess open in said sliding surface.