Internal gears, also known as ring gears, have the same standards as an external gear except that the teeth are cut into the inside diameter while the outside is smooth. Internal gears can provide a compact solution that delivers significant speed reductions and reduced sliding wear action, meaning you'll get increased longevity. When it's necessary to have two parallel shafts rotate in the same direction, internal gears eliminate the need for an idler gear. Internal gears can be applied in a wide range of equipment and applications.

China Ring Gear

Ring Gears

Advantages of Internal Gears

A special feature of spur and helical gears is their capability of being made in an internal form, in which Internal Gear mates with ordinary external gear. This offers considerable versatility in the design of planetary gear trains and miscellaneous instrument packages. The advantages of an internal gear are the following:

1) Well suited to compact design since the center distance is less than for external gears.
2) A high contact ratio is possible.
3) Good surface endurance due to a convex profile surface working against a concave surface.

Where Are Ring Gears Used?

Ring gears are used in various types of mechanical systems. They help transmit torque and power to different components by rotating. For example, in a car, the drive shaft turns the ring which rotates the drive axle and wheels. The larger the ratio between the ring and the pinion, the higher the torque and power produced.

The different types of ring gears all have different properties and use different materials. A typical set can achieve a wide range of ratios and teeth in a

Ring Gears Internal Gears

single revolution, while a partial gear set will have a different set of ring gear teeth on each revolution. The reduction ratio, design window, and other factors must all be carefully considered before selecting gear for a particular application.

Ring gears are made from different materials, including steel and aluminum. They can be forged into many shapes and sizes. Some manufacturers have CAD/CAM technology and can custom-make them out of a variety of metals. For example, some can be machined out of stainless steel, while are made from plastic or Delrin. If you need something fabricated out of steel or aluminum, ring gears are a great choice.

A ring gear has a complex shape. The ring itself has five sections, each representing a different part of the gear. These parts are connected by a bending or torsional spring.

Applications of Internal GearsRollers

  • Electric Screwdrivers
  • Pumps
  • Positioning Equipment
  • Automotives
  • Bicycle components
  • Planetary gear drives

What is the Function of the Ring Gear?

The ring gear is a part of the differential. It functions in transmission of torque from the axle to the wheels. The ring gear is made up of several components. These components are arranged in a series. The first of these components is the gear. The second part is the pinion.

The pinion has teeth on its top land that mesh with the ring gear. Its offset determines how closely the teeth will meet the ring gear's center axis. Backlash, or sliding friction, is the result of this interaction. If the pinion is too tight or too loose, the two gears are unlikely to mesh properly, which can cause excessive heat and gear wear.

The ring gear starts out as a rough billet or forged shape and undergoes several processes before it is finished for use in axles. The final product has a hard outer surface while a softer inner core. In addition to these, ring gears are subjected to an additional process known as heat treatment.

In automotive applications, the ring gear is located in the front of the differential case. The ring gear is often referred to as the hypoid gear because it is derived from the hyperboloid, which revolves. The ring gear is critical to the axle's performance, and improper positioning of the gear can cause the axle to become damaged.

Internal Gears

How Are Internal Gears Manufactured?

Internal gears are created using a pinion cutter and a shaping procedure. External gears are shaped mainly by hobbing, milling, and shaping with a rack cutter. However, other gear cutting techniques such as punching, etching, and laser engraving may be used in some cases.

The first step in the manufacturing process is to select a material for the gear teeth. These materials include steel, aluminum, plastic, wood, and others. Each has advantages and disadvantages that make one material or another better suited for particular applications.

Next, the geometry of the gear teeth is cut into the selected material using a gear cutting machine. The depth of the cut determines the number of teeth on the gear wheel. Each time the gear cutting machine cuts into the material, it leaves a layer of waste material called “dross” that must be removed from the tooth's surface before it will provide adequate protection against wear and tear.

After the teeth have been cut, they need to be polished to remove any remaining trash and give them a smooth finish. This is usually done by hand using a slurry of oil and water or alone as a lubricant. The gears are rotated against a stone plate with varying pressure to achieve the desired finish.

Selection Hints

Please select the most suitable products by carefully considering the characteristics of items and contents of the product tables. It is also important to read all applicable notes before the final selection.

Caution in Selecting Mating Gears
HZPT stock internal gears can mate with any spur gears of the same module, however, there are cases of involute, trochoid and trimming interference occurrences, depending on the number of teeth of the mating gear. Various types of interference and their symptoms and causes are tabulated below, also shown, the number of teeth of allowable mating pinions.

Interferences and the Symptoms

Involute interference The tip of the internal gear digs into the root of the pinion. Too few teeth on the pinion.
Trochoid interference The exiting pinion tooth contacts the internal gear tooth. Too little difference in number of teeth of the two gears.
Trimming interference Pinion can slide in or out axially but cannot move radially. Too little difference in number of teeth of the two gears.


As a professional ring gear manufacturer in China, Ever-power can provide a wide range of high-quality China internal gears. Additionally, custom ring gears are available. Apart from large and small ring gears, we also offer planetary gears, worm gears, bevel gears etc. Contact us now to get more info! 

Ring Gear for Sale

A ring gear is one of the most common types of gears used in automobiles. It is used to transmit torque from one end of the vehicle to the other. There are several different ways to do this. Nowadays, ring and pinion gears are the most common type of gear used in the automotive industry. They are stronger, quieter, and are suitable for higher reduction ratios.