Both pulley and gear carry the rotating motion between the two objects via rope, string, or belt.
The way of working of both gear and pulley are pretty similar. But some of the properties may change. The comparison analysis of gear vs pulley gives an account of the difference and similarities.
Comparison between gear vs pulley
The comparative analysis of gear vs pulley is given in the table below, which may help you understand gear and pulley properties.
| Gear | Pulley | |
| Definition | The gear consists of two rotational shafts fitted with the interlocking tooth-like structures placed in an equal interval. | Pulley consists of the simple wheel or axel in which the rope or a cable moves over. |
| Torque | The transmission torque acting on the gear is always greater. | Since the pulley uses the string for the transmission, the torque depends on the tension acting on the string. So the transmission of torque is less. |
| Tension | The gear does not need any medium for transmitting the motion, so the gear system is free from the tension. | The rope or cable used in the pulley exerts tension force, which affects the motion transmission |
| Distance | Gears are employed, where the transmission of motion takes place in a short distance. | Pulleys are employed to transmit the motion of a longer distance. |
| Power loss | There will be a loss in power during transmission. | The loss of power is relatively less in the case of the pulley system. |
| Change in the direction | The gear can reverse the direction of the motion by turning the two shafts in the opposite direction. | Pulley can also reverse its direction by moving the load along the circumference of the wheel or axel. |
| Speed | The gear offers a high speed of rotation. | It isn’t easy to achieve high speed in the case of a pulley. |
| Lubrication | Lubrication has to be done on the gear system regularly to work efficiently. | The pulley does not require any lubrication for its better performance. |
| Safety | The use of a gear system is safe for transmitting the motion as the gear does not slip. | Safety in the pulley system is lesser compared to the gear system because the pulley rope slip often. |
| Maintenance | The cost of maintenance of the gear is more, and it has longer life. | The maintenance cost of the pulley is less, and it has a shorter life span. |
| Nature of the equipment | The equipment used in gear is bulky. | The pulley uses lightweight equipment. |
| Efficiency | The efficiency of the gear is more because power loss is less. | The efficiency of the pulley is less because there is a loss of power due to friction and tension. |
| Purpose | The purpose of using the gear in the mechanical system is to change the direction and speed of the system. | The purpose of the pulley is to lift the massive object, and it can also change the direction. |
Some need to know facts
- Both gears and pulleys exhibit rotational motion.
- Gears are continuously operated in pairs.
- Pulley does not provide the mechanical energy on its own it just transfers the motion.
- Gear uses parallel shafts for the operation.
- Gears are employed in machines, automobiles, clocks and in some manufacturing tools.
- Gears are available not only in a circular shape; they have come in cone and square shapes also.
Frequently Asked Questions
What is the major advantage of gears over pulleys?
The major advantage of using gear is to achieve constant velocity.
Even though the pulley covers a more considerable distance but it is difficult to achieve constant velocity. An additional force of “friction” is acting on the pulley, which reduces the torque so that the velocity keeps changing. But in the case of gear, torque is more so we can achieve the constant velocity.
Which is more efficient, pulley or gear?
The efficiency of the gear is more than the pulley.
Since the torque acting on the gear system is more, it offers more efficiency, about 99%, but the pulley offers an efficiency of 94-96%. It is because the pulley may slip so that there will be a loss of transmission power.
What are the advantages of pulley over gear?
A pulley can be operated at a longer distance also. This is one of the main advantages of the pulley over gear.
A pulley is a simple mechanical system that can be employed easily compared to the gear. And pulleys are not too bulky to carry. And the main advantage of the pulley is that lubrication is not needed for the efficient functioning of the pulley. To change the ratio of driving and driven pulleys are more suitable than the gear.
Why is lubrication mandatory for the operation of gear?
Lubrication is the method of oiling the gear system for better performance.
Lubrication prevents the friction between the teeth of the gear system, and it controls the rise in the temperature produced due to rolling and sliding friction between the teeth.
Explain the working of gear.
A gear is a wheel with a tooth-like structure that transfers the mechanical energy from one system to another.
The gear is provided with two axels. The one is the driving wheel, and the other is the driven axel—both consisting of teeth-like structures. If the first wheel rotates in the clockwise direction, the second one also rotates in the same direction by locking the tooth of one another. These wheels turn by interlocking teeth and promote mechanical energy.
How does torque influence the gear to promote the transmission?
In order to bring the gear in motion, torque is an essential component of the gear.
Torque involved in the gear reduces the internal friction between the teeth of the axels. Hence the rotational speed increases this made to increases the mechanical transmission of motion. So that efficiency of the gear also increases proportionally.
What are the factors involved in the energy loss in a pulley?
The factor involved in the energy loss in the pulley are given below
Friction – since the pulley does not need any lubrication, there will be a regular frictional force between the wheel and the cable; this reduces the energy of the pulley.
What are the disadvantages of the gear?
As the gear has several advantages, but there are several disadvantages also.
- The gears cannot be employed when a significant distance separates the two axels.
- The gear system produces noise and vibration, which may sometimes affect efficiency.
- The lubrication has to be done regularly for better performance.
- These mechanical systems are not so flexible. It works in a limited area.
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I am Keerthi K Murthy, I have completed post graduation in Physics, with the specialization in the field of solid state physics. I have always consider physics as a fundamental subject which is connected to our daily life. Being a science student I enjoy exploring new things in physics. As a writer my goal is to reach the readers with the simplified manner through my articles.