DRIVE SHAFTS and UNIVERSAL JOINTS OBJECTIVES v Describe

DRIVE SHAFTS and UNIVERSAL JOINTS

OBJECTIVES v Describe purpose and construction of common RWD drive shafts. v Describe purpose and construction of common universal joint designs. v Importance of driveshaft balance. v Explain natural speed variation. v Describe the canceling universal joint angles.

INTRODUCTION v Drive shaft - transfers power from trans to differential. v Drive shaft is made from seamless steel tubing with yokes at each end. v Some vehicles use two piece drive shafts. v Four-wheel-drive use two drive shafts. v Some axle shafts are made like drive shafts.

DRIVE SHAFT CONSTRUCTION v Typical universal joint and yokes.

DRIVE SHAFT CONSTRUCTION v As the differential travels up and down U-joint angle changes. v The distance between trans and differential also changes. v U-joints permit change in angle. v Slip yoke allows change in length. v Drive shafts have a natural tendency to vibrate.

MOVEMENT

Types of Drive Shafts v Hotchkiss - External shaft and U-joints. § Can be either one or two piece. v Torque tube - drive shaft is enclosed. § Ridged shaft. v Torque tube § Flexible shaft.

UNIVERSAL JOINTS v U-joints are crosses between two Y-shaped yokes. v Because U-joints transfer power at an angle they DO NOT rotate at a constant velocity nor are they vibration free.

SPEED VARIATIONS v Input and output speeds are the same. v But the drive shaft itself speeds up and slows down every 90 degrees.

PHASING of U - JOINTS v To provide for this canceling effect, drive shafts should have at least two U-joints and their angles must be slight and equal to each other. v Speed fluctuations can be canceled if the driven yoke has the same point of rotation, or same plane , as the driving yoke.

CANCELING ANGLES v Vibrations can be reduced by canceling angles.

TYPES of U - JOINTS v Single universal joint retained by either an inside or outside snap ring. § Spicer - outside snap ring § Mechanics or Detroit - inside snap ring v Universal joints held in the yoke by U-bolts or lock plates.

DOUBLE CARDAN Coupled Universal Joint v Total operating angle is divided equally between the two joints. v Because the two joints operate at the same angle, fluctuations are canceled out. v Double Cardan is classified as a constant velocity joint.

MAINTENANCE v Factory joints do not have grease fittings. v Replacement joints need servicing. v Dirt and other buildup on the shaft will affect its balance.

BIBLIOGRAPHY: www. Careernet. com Step 1 Chasis and Power Train, Toyota Astra Motor Step 2 Chasis and Power Train, Toyota Astra Motor

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