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Sector Gears: Design, Functionality, Applications and Selection Insights

Sector Gears: Design, Functionality, Applications and Selection Insights

  • By: Swadeshi Engineering Enterprises Private Limited
  • 2026-01-30
Sector Gears: Design, Functionality, Applications and Selection Insights

It is a well-understood fact that not every application requires a complete circular gear in mechanical power transmission systems. Many operations require only a limited angle and not a complete circle. It is here that the role of sector gears comes into play. They offer accurate angular motions and are small and compact. They offer efficient torque transmission for irregular operations. 

Since we have understood what sector gears do, let us continue with the blog and learn about sector gears from a design perspective. We will also talk about their geometry, how they are manufactured, the materials they are made of, their applications, benefits, limitations, and factors you must consider before selecting them. 

Understanding Sector Gears in Mechanical Systems

The name says it all. A Sector Gears, also known as a partial gear, has a sector, or a part of a complete circular gear. They are not made for a complete circular gear. They are usually used in mechanical systems where:

  • Motion is needed only up to a fixed angle
  • Space restrictions prevent complete gear installation.
  • Accurate positioning is important

These features have made sector gears a popular choice in industries like automation, steering systems, and machining. 

Geometry and Design Characteristics of Sector Gears

Here is a glimpse into the geometric design of sector gears.

  • Arc Length: Arc length defines the angle of rotation for sector gears (e.g., 30°, 90°, or 180°)
  • Pitch Diameter: The pitch diameter is compatible with the mating gear. 
  • Module: Also known as the diameter pitch, the module defines the tooth size. 
  • Pressure Angle: The pressure angle is usually maintained at 20°. It is directly related to the capacity of the gear. 
  • Tooth Profile: The tooth profile is curled spirally for optimum transmission of power. 

Manufacturing Methods Used for Sector Gears

Depending on the precision requirement and the type of material, sector gears are made up of either of the following methods. 

  • Gear Hobbing
    This method is used for medium- and large-scale production.
  • Gear Shaping
    This method is excellent for applications where close tolerances are needed.
  • CNC Milling
    CNC milling is used for manufacturing sector gears for low-volume industrial operations.
  • Casting and Machining
    This method is used for manufacturing large sector gears where the strength of the gear is preferred more than precision.
  • Forging
    This method is used in the manufacturing of strong sector gears. They are widely used in heavy-duty industries. 

Methods like grinding and heat treatment are used to improve the durability of the gears. 

Materials Commonly Used for Sector Gears

Material selection directly affects gear strength, lifespan, and operating performance.

Common Materials and Their Properties

Material

Key Properties

Typical Applications

Carbon Steel

High strength, economical

General machinery

Alloy Steel

High load capacity, wear resistance

Heavy-duty industrial systems

Cast Iron

Vibration damping, cost-effective

Large, slow-speed mechanisms

Stainless Steel

Corrosion resistance

Food, chemical, marine applications

Bronze

Low friction, good wear properties

Mating with steel pinions

Engineering Plastics

Lightweight, quiet operation

Automation and light-duty systems

Functional Advantages of Sector Gears

Here are some of the operational benefits offered by sector gears. 

  • Small design (can be installed in places with limited space)
  • Light in weight
  • Less manufacturing cost
  • Accurate positioning
  • Efficient torque transfer

Typical Applications of Sector Gears

Below are some of the basic applications of sector gears:

  • Industrial Machinery

In industrial machinery systems, sector gears are used for lifting systems and irregular drives. 

  • Automotive Systems

In automotive systems, sector gears are used in providing controlled and adjustable seating mechanisms. 

  • Robotics and Automation

In robotics and automation, the sector gears are used for providing accurate angular movement. 

  • Machine Tools

Sector gears are used in controlled motion assemblies.

  • Packaging and Printing Machines

In packaging industries, the sector gears are used for tasks involving controlled machine positioning. 

Sector Gears vs Full Gears: The Major Differences

While full Gears provide continuous motion, sector gears are better suited when:

  • Only partial rotation is required
  • System space is limited
  • Weight reduction is important
  • Cost optimization is a priority

Maintenance and Service Life Considerations

Proper maintenance can significantly extend the life of sector gears. Provide proper lubrication to the gears at regular intervals. Keep an eye out for noise levels. 

FAQs on Sector Gears

Q1. What is the primary function of a sector gear?

A sector gear provides controlled angular motion over a limited arc instead of continuous rotation.

Q2. Can sector gears transmit high torque?

Yes, when properly designed and manufactured, sector gears can handle significant torque, especially at low speeds.

Q3. Are sector gears custom-made?

Most sector gears are custom-designed based on application requirements such as arc length, load, and material.

Q4. What is the difference between a sector gear and a rack?

A sector gear provides rotational motion, while a rack converts rotation into linear motion.

Q5. Where can I get the best quality sector gears? 

For procuring the best quality sector gears, you can always connect with Swadeshi Gears. The brand is known for offering the best quality sector gears, precision gears, and other types at the best prices.

Conclusion

Industries that require controlled and limited angular movement and not complete movement need sector gears. These gears work well in systems automation systems, machine tools, OEMs, and many more. You must ensure that you procure the product from trusted manufacturers like Swadeshi Gears. The brand is known for providing the best gear at competitive prices. Let us connect now.

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