Front drive cars transfer the engine power; Engine - Transmission - Differencial gear - Drive shaft - Wheel. Constant velocity joint being assembled into driveshaft transfers engine power to the shaft at changing angles and axial movement and then to the wheel

Spider; Tripod spider transfers the engine power at various angles. Ball case; Ball case(Spherical roller) being assembled into housing make stroke actions at various angles inside housing track as wheel rolls. Needle rollers; Needle rollers assembled into ball case smoothes spider movement. Ring; Ring being assembled into spider groove holds surrounding parts. Retainer; Retainer being assembled onto spider holds parts in position.