Piston for automatic transmission

A piston for an automatic transmission, comprising:

• a cylindrical wall portion provided by a first piston member;
• a bottom wall portion provided by a second piston member;
• and
• an engaging portion at which said first and second piston members are engaged with each other such that said first piston member is movable relative to said second piston member in an axial direction of said piston by a small distance,
• wherein said piston further comprises an elastic structure which is provided at said engaging portion, and which biases said first piston member in said axial direction, so as to restrain movement of said first piston member relative to said second piston member in said axial direction,
• wherein said first piston member has, in an axially end portion thereof, at least one engaging groove at which said first piston member is engaged with said second piston member,
• wherein said second piston member has at least one elastic lug each provided by a portion thereof that is inclined with respect to a radial direction of said piston, and
• wherein said elastic structure includes said at least one elastic lug that is held in contact with a radially extending surface of said first piston member, said radially extending surface defining a corresponding one of said at least one engaging groove and being substantially parallel to said radial direction.

A piston for an automatic transmission, comprising:

• a cylindrical wall portion provided by a first piston member;
• a bottom wall portion provided by a second piston member;
• and
• an engaging portion at which said first and second piston members are engaged with each other such that said first piston member is movable relative to said second piston member in an axial direction of said piston by a small distance,
• wherein said piston further comprises an elastic structure which is provided at said engaging portion, and which biases said first piston member in said axial direction, so as to restrain movement of said first piston member relative to said second piston member in said axial direction,
• wherein said first piston member has at least one elastic lug each provided by a portion thereof that is inclined with respect to said axial direction of said piston,
• wherein said second piston member has a radially extending surface which is substantially parallel to a radial direction of said piston, and
• wherein said elastic structure includes said at least one elastic lug each of which is held in contact at a distal end portion thereof with said radially extending surface.

A piston for an automatic transmission, comprising:

• a cylindrical wall portion provided by a first piston member;
• a bottom wall portion provided by a second piston member;
• and
• an engaging portion at which said first and second piston members are engaged with each other such that said first piston member is movable relative to said second piston member in an axial direction of said piston by a small distance,
• wherein said piston further comprises an elastic structure which is provided at said engaging portion, and which biases said first piston member in said axial direction, so as to restrain movement of said first piston member relative to said second piston member in said axial direction,
• wherein said elastic structure includes an elastic member disposed in said engaging portion and interposed between said first and second piston members, such that said elastic member is held in contact with said first and second piston members.