Control Arm

Functions of Control Arm and Ball Joint

Among independent suspension system there are double wishbone type, strut type, multi-link type, trailing arm type etc. A crucial part being a decisive element for wheel alignment where chasis connects to wheel.
To ensure straight running and steering. Wheel alignment becomes important as driving performance is affected by vehicle position such as rolling etc.
Connected through rubber bush to chassis and fastened by ball joint at wheel side. It absorbs position changes by road conditions and keeps shocks/vibrations away from chassis.

Construction of Control Arm and Ball Joint

Consists of upper arm and lower arm. Rubber bush is installed to chassis side and a hole is equipped at wheel side for ball joint to connect. Arm itself is made by sheet metal, forged steel, aluminium alloy or cast iron etc in order to resist multiple bouncing forces as vehicle drives, brakes and receives lateral forces etc.
Ball joint mounts in various ways like bolt, rivet or press-fit type. Integral type(arm + ball joint) also exists.

Ball joint consists of housing which mounts on control arm and ball stud which fits on wheel. Resin compound sheet is inserted between ball stud and housing. Plug or cap is utilized and housing is caulked to seal the internal grease. The other end has a dust cover filled with grease to cope with infiltrating mud and water.

Mounting type to control arm varies like bolt, rivet, press-fit and arm-unitized. Mounting type to wheel is either by upper fastening type or pinch-bolt fastening.
By internal ball seat material ball joint is divided into metal type and resing compound type. Metal type takes grease nipple for continuous greaseup. Grease nipple is not necessary for resin compound type, as special grease is sealed in at manufacturing site.
GMB adopts resing compound type recently.

GMB will respond with confidence to the diverse needs of our customers!