Ball joint

A ball joint for connecting relatively movable parts of a vehicle, said ball joint comprising:

• a socket defining a chamber and having an opening;
• a ball stud having a ball portion and a stud portion extending from said ball portion, said ball portion being located in said chamber and said stud portion projecting through said opening;
• means associated with said ball stud for enabling rotational movement of said ball stud about its longitudinal central axis relative to said socket and for enabling pivotal movement of said ball stud relative to said socket;
• seal means defining first and second fluid chambers in said chamber defined by said socket;
• electrorheological fluid located in said first and second fluid chambers for resisting relative rotational and pivotal movement, respectively, of said ball stud and said socket, the viscosity of said electrorheological fluid in said first and second fluid chambers being controllable by an electric field applied thereto and being variable to vary the resistance to relative rotational and pivotal movement between said ball stud and said socket;
• first means for applying a first electrical field to said electrorheological fluid in said first fluid chamber to resist rotation of said ball stud about its longitudinal axis relative to said socket, said first means comprising a first conductive plate in said first fluid chamber for applying an electric field to said electrorheological fluid to control the viscosity of said electrorheological fluid in said first fluid chamber and thereby control relative rotational movement of said ball stud and socket, an electrical conductor connected to said first conductive plate for delivering electrical energy of said first conductive plate, and another electrical conductor connected to said ball stud, said electric field being applied to said electrorheological fluid in said first fluid chamber when electrical energy is delivered to said first conductive plate;
• and
• second means for applying a second electrical field to said electrorheological fluid in said second fluid chamber to resist said relative pivotal movement between said ball stud and said socket, said second means comprising a second conductive plate in said second fluid chamber for applying an electric field to said electrorheological fluid to control the viscosity of said electrorheological fluid in said second fluid chamber and thereby control relative pivotal movement of said ball stud and socket, an electrical conductor connected to said second conductive plate for delivering electrical energy to said second conductive plate, said electric field being applied to said electrorheological fluid in said second fluid chamber when the electrical energy is delivered to said second conductive plate.