Universal joints allow drive shafts in vehicles to transmit power between non-parallel rotating shafts, like between the transmission and wheels, to allow for suspension movement. They have been used since antiquity based on gimbal designs. Modern universal joints can be made of steel or plastic and are used in many applications where shafts intersect at an angle. They provide advantages like large angular displacement capability but have disadvantages like output speed and acceleration fluctuations depending on the operating angle.

1. UNIVERSAL
JOINTS

2. WHAT IS UNIVERSAL JOINT
?
• Universal joint is a positive, mechanical connection between
rotating shafts, which are usually not parallel, but intersecting.
They are used to transmit motion, power, or both. The simplest
and most common type is called the Cardan joint or
Hooke joint.

4. HISTORY OF UNIVERSAL JOINT
• The main concept of the universal joint is based on the design
of gimbals, which have been in use since antiquity. One anticipation
of the universal joint was its use by the ancient Greeks
on ballistae. In Europe the universal joint is often called the
Cardano joint or Cardan shaft, after the Italian
mathematician Gerolamo Cardano; however, in his writings, he
mentioned only gimbal mountings, not universal joints.
• The term Cardan joint appears to be a latecomer to the English
language. Many early uses in the 19th century appear in
translations from French or are strongly influenced by French
usage. Examples include an 1868 report on the Exposition
Universelle of 1867[18] and an article on

5. MATERIAL USED IN UNIVERSAL
JOINTS
• Universal joints are available in steel or in thermoplastic body
members. Universal joints made of steel have maximum load-
carrying capacity for a given size. Universal joints with thermoplastic
body members are used in light industrial applications in which their
self-lubricating feature, light weight, negligible backlash, corrosion
resistance and capability for high-speed operation are significant
advantages.
Universal joints of special construction, such as ball-jointed
universals are also available. These are used for high-speed
operation and for carrying large torques. They are available both in
miniature and standard sizes.

6. APPLICATIONS OF UNIVERSAL
JOINTS
• Typical applications of universal joints include aircraft,
appliances, control mechanisms, electronics, Instrumentation,
medical and optical devices, ordnance, radio, sewing machines,
textile machinery and tool drives.

7. GENERAL CHARACTERISTICS OF THE UNIVERSAL
JOINT
• A basic characteristic of the Cardan joint is the nonuniformity of
motion transmission through the joint. The angular-velocity ratio
between input and out put shafts varies cyclically at two cycles per
revolution of the input shaft. This fluctuation, which is accompanied
by corresponding angular accelerations, increases with the operating
angle and can be as much as 15% of peak angular velocity (in the
case of a 30° operating angle). In selecting a joint the effect of these
fluctuations on static torque, inertia torque and system performance
needs to be kept in mind.

8. ADVANTAGES AND
DISADVANTAGES
OF UNIVERSAL JOINT
• Single Cardan joints have the following advantages:
• Low side thrust on bearings.
• Large angular displacements are possible.
• High torsional stiffness.
• High torque capacity.
They have the following disadvantages:
• Velocity and acceleration fluctuation increases with operating angle.
• Lubrication is required to reduce wear.
• Shafts must lie in precisely the same plane.
• Backlash difficult to control.

9. EQUATION OF
MOTION
• The Cardan joint suffers from one major problem: even when the input drive
shaft axle rotates at a constant speed, the output drive shaft axle rotates at a
variable speed, thus causing vibration and wear. The variation in the speed of
the driven shaft depends on the configuration of the joint, which is specified by
three variables:
• γ1 the angle of rotation for axel 1
• γ2 the angle of rotation for axel 2
• β the bend angle of the joint, or angle of the axles with respect to each other,
with zero being parallel or straight through.
•γ 2 =tan^-1 {tan γ 1/cos β}

10. EQUATION DIAGRAM
γ 2 =tan^-1 {tan γ 1/cos β

11. GRAPH OF MOTION

12. KINEMATICS
• For a uniformly rotating input shaft, the output shaft angular -
velocity and angular acceleration undergo two cycles per
revolution of the input shaft. The angular displacement of the
output shaft does not precisely follow that of the input shaft
but leads or lags, again with two cycles per revolution. The
angular-velocity variation as a function of operating angle is
illustrated .

13. THE EFFECT OF SHAFT ANGLE (ß) ON SINGLE
UNIVERSAL JOINT PERFORMANCE FOR
CONSTANT INPUT SPEED*

14. JOINT SELECTION (TORQUE
RATING)
• The capacity of a universal joint is the torque which the joint can transmit. For a
given joint, this is a function of speed, operating angle and service conditions. Table
2 shows use factors based on speed and operating angle for two service conditions:
intermittent operation (say, operation or less than 15 minutes, usually governed by
necessity for heat dissipation) and continuous operation. The torque capacity of a
single Cardan joint of standard steel construction is determined as follows:
• 1. i. From the required speed in RPM, operating angle in degrees, and service
condition (intermittent or continuous), find the corresponding use factor from Table
2.
ii. Multiply the required torque, which is to be transmitted by the input shaft, by the
use factor. If the application involves a significant amount of shock loading, multiply
by an additional dynamic factor of
• 2. The result must be less than the static breaking torque of the joint.
iii. Refer to the torque capacity column in the SOP catalogue and select a suitable
joint having a torque capacity not less than the figure computed in (ii), above. If a
significant amount of power is to be transmitted and/or the speed is high, It is

15. USE FACTORS FOR THE TORQUE
RATING OF UNIVERSAL JOINTS

16. WHY UNIVERSAL JOINT ONLY USE
IN TRANSMISSION SYSTEM OF
VEHICLES ?
•Universal joints allow drive shafts to move up
and down with the suspension while the shaft
is moving so power can be transmitted when
the drive shaft isn't in a straight line between
the transmission and drive wheels. Rear-wheel-
drive vehicles have universal joints (or U-joints)
at both ends of the drive shaft.

17. IMPORTANCE OF UNIVERSAL
JOINT
• Universal joints allow drive shafts to
move up and down with the
suspension while the shaft is moving
so power can be transmitted when
the drive shaft isn't in a straight line
between the transmission and drive
wheels. Rear-wheel-drive vehicles
have universal joints (or U-joints) at
both ends of the drive shaft.

18. WHAT HAPPENS IF WE DON’T USE
UNIVERSAL JOINT ?
•Without universal joints or some similar system, it
would be impossible for a vehicle to have a
suspension that offers any substantive wheel
travel. The driveline would bind with every bump
and pothole. Front-wheel-drive vehicles have
constant velocity joints, or CV joints.

19. ORTHOGRAPHIC VIEW OF UNIVERSAL
JOINT

20. THANK
YOU