Propeller shafts and universal joints

Propeller shaft:

Movement from the gearbox is transferred to the differential which is the next component of the transmission system. The differential is located in the centre of the rear axle and the vehicle is rear-wheel drive. Alternatively, the vehicle can be a front-wheel-drive or, in some cases, engine motion can be transferred to both the front and rear axles.

In the case of a rear-wheel-drive vehicle, the distance between the gearbox and the differential can be considerable and the driveshaft connecting the two has a considerable length. In the case of front-wheel drive, the distance between the two could be small and therefore a small driveshaft would be needed. To study the driveshaft it is worth considering a rear-wheel-drive vehicle.

Functions of the propeller shaft:

In most motor vehicles, the engine is located at the front and the rear wheels of the vehicle are powered. This arrangement requires the use of a longer drive shaft. In some configurations, two or three drive shafts are used to compensate for the length. The propeller shaft is the post that transmits gearbox control to the differential rigging in a motor vehicle from the engine to the propeller in a boat or flying machine.

REQUIREMENTS OF PROPELLER SHAFT:

To realize production capabilities, the next ones are normal in a driveshaft

1. High torsional quality: therefore they are made with a sturdy or hollow round cross segment
2. Hardened and Solidified: Therefore, they are made of prevailing quality steel and are solidified for enrollment
3. Joint efficiently: so they are mostly welded by submerged carbon dioxide welding process.
4. Dynamic Tuning: As the spinning wonder could be crucial at higher rates, prop shafts are tested on the electronic tuning machine as a result.
5. Reduced thrust loads: as reverberation is risky for the life of the tree. It also transmits excessive unique power to the pole’s terminal supports, so its event should be kept at a strategic distance.

TYPES OF PROPELLER SHAFT:

1. One piece propeller shaft:

• Used in vehicles with a short distance between the engine and axles and MR-based four-wheel drive vehicles.

• The friction welding used at the joint helps to improve the strength, quality and durability of the joint.

 2. 2 Piece / 3 Piece Propeller Shaft:

1. Used as part of vehicles with a long distance between the engine and axles and four-wheel drive vehicles with front engine front drive base.

2. Splitting the propeller shaft into two or three parts reduces the critical RPM, preventing vibration problems from occurring when the overall shaft length is increased.

3. Universal Joints: (Coupling Hooks)

Robert Hooke is commonly known as the inventor of the “Hooke Joint” or “Universal Joint”. There are various names used for universal joints such as universal joint, U joint, gimbal, Spicer joint or Hardy Spicer joint.

Universal joints are mainly used to create flexible connections between two rigid angled shafts. Allows for constantly variable power transmission. It is used to connect the driveshaft with the shift shaft to transmit rotary motion.

Power transmission under varying conditions is impossible without the use of a flexible device or gimbal. This flexible device is also used in vehicles having coupling shafts between clutch and gearbox, between main gearbox and auxiliary gearbox and also on the drive shafts of the driven front axle.

TYPES OF UNIVERSAL JOINT

1. Variable speed couplings

• Cross or spider type

• Type of ringtone

• Ball and trunnion type

2. Constant speed couplings (CV)

• Rzeppa

• Bendix Weiss

• Treated

1. Variable speed couplings

In this case, both the driven shaft and the crankshaft do not rotate at the same speed even though each part of a revolution is at the same number of revolutions. The driven and motor shafts must be positioned in a straight line to turn at the same speed through each part of a revolution. But in practice, it won’t be feasible in any car. The crankshaft is always inclined.

If there is an angle between the driven shaft and the crankshaft, the driven shaft will be less than the crankshaft by half a turn and faster than the crankshaft for the other half turn. Hence, the average speed of the driven shaft equals the crankshaft. The speed variation in the driven shaft increases as the bending angle of the universal joint increases.

If two variable speed universal pairs are used in two transmission lines, the yoke on the shaft connected to the universal pairs must not be indifferent planes. Provides balance to changes in speed.

Variable Velocity Joints are following These Types

• Cross or spider type
• Ring type
• Ball and trunnion type

Cross or Spider Type:

In universal joints, the two yokes where one is connected to the drive shaft and the other is connected perpendicular to the driven shaft to the shaft driven by a cross or spider. Needle bearings are mounted between the yokes and the transverse ends. These types of couplings are generally used in crankshafts.

Ring Type:

This type of joint uses a flexible ring. The rod has two or three armed spiders. The arms are bolted to opposite faces of the flexible ring. The arms of one spider are placed halfway between the arms of the other. The flexible ring consists of one or more rubber rings to provide sufficient strength

Ball and pin type:

This type uses a combination of universal and sliding joints in a single assembly. A pin or cross shaft is connected transversely in a “T” shape to the end of a shaft of the gimbal. A ball is mounted on needle roller bearings at each end of the cross shaft. The complete unit slides freely in the grooves made in the external body of the joint. The heavy spring resists excessive longitudinal movement of the shaft.

Power is transmitted through the pin, balls and cross shaft. Bending moment occurs by rolling the ball in one direction. It is also in the opposite direction by moving the balls longitudinally in the grooves of the pin. The open end of the shaft is covered by leather or rubber boot covers.

2. Constant Velocity joints

In this type of joint, the driven shaft is rotated at the same speed that the drive shaft rotates through each part of revolution at any degree of deflection. These couplings are mainly used in the front drive axles to transmit power over large angles. Cadillac cars use ball and socket type CV joints in their drive shafts.

Rzeppa :

It consists of internal and external spherical races in which the grooves are cut parallel to the shaft. The steel balls are placed in the grooves on the spherical races. Torque transmission occurs from one stroke to the other ball. The circular pattern of the spheres causes the shafts to rotate at the same speed.

Bendix Weiss:

In this type of articulation the principle of crossing spheres arranged in a circle around a sphere is used. Four numbers of drive balls are placed in tracks machined in tight fitting yokes. A central fifth ball is held between two yokes as an inside run. The guide balls are arranged in a circle in the same way as the Rzeppa joint. The ball alignment action provides a Constant Velocity joint.

Tracta :

This joint differs from the two previous joints. Four yokes are used in this joint where two yokes are attached to the shafts and the other two are floating in the center of the joint. The mating parts of the yokes are transformed into segments of a circle. Both the circular segments and the floating action of the two yokes provide a constant velocity joint.

WORKING OF UNIVERSAL JOINT

1. In the case of an automobile, the gearbox is rigidly mounted. Due to the action of the road springs, the position of the rear axle is constantly varied and tolerance is provided if the gearbox is mounted on the rear axle via a driveshaft.
2. A gimbal consists of two yokes. These yokes are attached to each end of the shaft. The two yokes are joined by a central or connecting crosspiece. The connecting cross member will turn the yoke bearings as the angularity between the shafts changes. They do not transmit motion evenly if the trees run at an angle.
3. Materials used for universal joints
4. Universal joints can be made from almost any material depending on the application.
5. Common materials used include stainless steel, steel, naval brass, and other similar alloys to handle higher torques and temperatures.

APPLICATIONS OF UNIVERSAL JOINT

• Universal joints vary according to the composition of the material, the type of hub and the applications for which they are designed, it is a positive mechanical joint that is used to connect the shafts.
• The universal joint is most commonly found in the driveshaft of rear-wheel drive cars.
• Specific applications of universal joints include aircraft, appliances, control systems, electronics, instrumentation, textile machinery, medical and optical equipment, radios, weapons, sewing machines and tool drives.

Advantages of Universal Joint

1. The universal coupling is more flexible than the swivel joint.

2. Facilitates torque transmission between angular misaligned shafts.

3. It is economical and convenient.

4. It is simple to assemble and disassemble.

5. The efficiency of torque transmission is high.

6. The joint allows angular displacements.

Disadvantages of Universal Joint

1. Wear can occur if the coupling is not properly lubricated.

2. Maintenance is often required to avoid wear.

3. The universal joint produces a floating motion

4. Does not support axial misalignment.