Fluid-filled active vibration damping device and method of producing the same

A method of producing a fluid-filled active vibration damping device including:

• a first and a second mounting member that are spaced apart from each other;
• an elastic body elastically connecting said first and second mounting members and partially defining a fluid chamber filled with a non-compressible fluid;
• an oscillating member partially defining said fluid chamber on one of opposite sides thereof;
• an electromagnetic actuator disposed on an other one of said opposite sides of said oscillating member and adapted to oscillate said oscillating member so as to control a pressure of said non-compressible fluid in said fluid chamber, said electromagnetic actuator includes:
• a coil having a bore;
• a yoke member made of a magnetic material and disposed in said bore of said coil so as to extend through said bore and protrudes axially outwardly from axially opposite end faces of said coil so as to form circumferentially extending magnetic pole portions on axially opposite sides of said coil;
• an oscillating sleeve member made of a magnetic material that is disposed radially outwardly of said yoke member with a given radial spacing therebetween such that said yoke member and said oscillating sleeve member are displaceable relative to each other in an axial direction of said electromagnetic actuator, said oscillating sleeve member being adapted to form at least one annular attractive portion;
• and an elastic support member for elastically positioning said oscillating sleeve member and said yoke member relative to each other in said axial direction, such that said at least one annular attractive portion of said oscillating sleeve member is opposed to at least one of said magnetic pole portions in a radial direction perpendicular to said axial direction, and is offset from each other in said axial direction, when said coil is in a non-energized state, said coil being energized in order to apply an axial driving force between said yoke member and said oscillating sleeve member on the basis of a magnetic force acting between said magnetic pole portions and said annular attractive portion mutually opposed to each other in said radial direction and offset from each other in said axial direction, and a cup-shaped retainer fixed to said second mounting member and adapted to accommodate said electromagnetic actuator such that said electromagnetic actuator extends in a direction in which said oscillating member is reciprocatory oscillated, said annular attractive portion is fixedly connected to said oscillating member on one of axially opposite sides of said electromagnetic actuator, and said yoke member is fixedly connected to a bottom wall portion of said retainer on an other one of said axially opposite side of said electromagnetic actuator such that said yoke member extends through said bottom wall portion of said retainer, wherein said first and said second mounting member and said elastic body and said fluid chamber cooperate to form a mounting assembly of said vibration damping device, said method comprising the steps of:
• preparing said mounting assembly and said electromagnetic actuator independently of each other;
• fixedly connecting said oscillating sleeve member of said electromagnetic actuator to said oscillating member of said mounting assembly;
• assembling said retainer with respect to said electromagnetic actuator such that said retainer is disposed radially outwardly of said electromagnetic actuator;
• and then
• fixing said retainer to a fixing member of said second mounting member and said yoke member of said electromagnetic actuator to said bottom-wall portion of said retainer such that said yoke member extends through said bottom wall portion of said retainer.