Spur Gear

A spur gear is a cylindrical toothed gear with teeth that are parallel to the shaft and is used to transfer mechanical motion and control speed, power, and torque between shafts. They are the most popular types of cylindrical gears and have a simple design of straight parallel teeth positioned equally around the circumference of the cylinder barrel.

Click Here

No Results Found

The page you requested could not be found. Try refining your search, or use the navigation above to locate the post.

What is a Spur Gear?

A spur gear is a type of cylindrical gear with straight teeth that are parallel to the gear axis. It is one of the most common types of gears used in various mechanical systems and power transmission applications. The teeth of a spur gear are cut on the outer surface of the gear cylinder and are oriented in a radial direction.

Spur gears are designed to transmit motion and power between parallel shafts. When two spur gears mesh together, their teeth engage and transfer rotational motion from the driving gear (also known as the pinion) to the driven gear. The teeth of the gears mesh in a rolling contact, producing a smooth and continuous transfer of power.

Types of Spur Gears

Planetary Spur Gear Drive

Planetary spur gear drives, known as epicyclic gearing, consist of a sun gear, which is the external spur gear, three or more planet gears, and a ring gear that are combined to make a planetary gear drive. The spur gears in a planetary spur gear drive move opposite to each other in the same plane.

External Spur Gear

The configuration of an external spur gear is typical of all types of gears, with the teeth of the gear on a cylindrical surface. When it engages with another gear, the gear will rotate in the opposite direction. The driving gear is usually smaller than the driven gear.

Internal Spur Gear

The teeth of the inner spur gear are cut on the inner surface of the gear. The outer surface is smooth and perfectly elliptical or circular. The inner teeth of the gear mesh with a small gear or smaller gear. The gears rotate in the same direction.

Type A Spur Gear

A type A spur gear does not have a hub and is flat with a small hole in the center. The circle of the root diameter is solid with the small hole placed in its center.

Pin Hub Spur Gear

The pin hub spur gear has a fixing screw that is used to secure the pin on the gear to the shaft. They can be connected to the shaft using positioning pins, springs, rollers, or tapered pins. The holes on the gears are drilled to the exact size of the pins to achieve a tight connection.

Spur Gear with Keyway

For keyway spur gears, cut a groove in the hole of the gear that matches the groove milled into the shaft. The keyway allows the shaft and gear to fit tightly together and align the grooves correctly. The purpose of the design is to eliminate sliding between the shaft and the spur gear.

Spline Spur Gear

For spline spur gears, the transmission shaft will be cut with ridges or teeth that match the grooves cut in the spur gear hole. There are different types of spline configurations, some are straight like keyways, and some are like involutes. The spacing between splines varies depending on the design of the gear. An involute spline spur gear can have up to 32 teeth of any number.

Split Hub Spur Gear

The split type hub has an opening along its axial plane, which is tightened with a fixture to tightly and firmly connect to the shaft, allowing it to be connected to any shaft. It is one of the easiest straight gears to assemble and disassemble.

How to Define a Spur Gear?

When customizing spur gears, the following are some common attributes and their explanations:

Pitch Circle: A pitch circle is a virtual circle located on a gear that contacts and transmits power to the pitch circles of other gears. The number of teeth of a gear is calculated based on the circumference of the pitch circle and determines the size and transmission ratio of the gear.
Diameter Pitch: Modulus is a measure of the density of gear teeth, which represents the reciprocal of the number of teeth per inch (or millimeter). The larger the modulus, the fewer teeth, and the larger the teeth of the gear. Module is one of the commonly used size standards for spur gears.
Pitch Diameter: The pitch diameter is the diameter of the pitch circle on the gear. For an external gear, the pitch diameter is equal to the pitch circle diameter; For an internal gear, the pitch diameter is equal to the diameter of the inter tooth circle.
Center Distance: The center distance is the distance between the axes of two gears. It determines the relative position and transmission ratio of the gears. The selection of center distance should consider the size of the gear, transmission efficiency, and required transmission ratio.
Spur Gear Addendum: Tooth Addendum refers to the top height of the gear teeth. It is the distance between the tooth pitch circle and the tooth tip circle.
Gear dedendum: Root height refers to the height of the root of the gear teeth. It is the distance between the tooth pitch circle and the tooth root circle.
Outside Diameter (OD): The outer diameter is the maximum diameter of a gear, usually the diameter of the outer edge of the gear.
Root Diameter: The root diameter is the diameter of the root of a gear tooth, usually the diameter of the tooth root circle.
Pressure Angle: The pressure angle refers to the angle between the gear rack and the gear tooth surface. The common pressure angle values are 20 ° or 14.5 °, which can affect the transmission efficiency and load distribution of gears.
Whole Depth: Full depth refers to the overall depth of the gear teeth, that is, the distance from the top of the tooth to the root of the tooth.
Module: Module is a unit of measurement for gear size, which represents the width of each tooth. A larger modulus means a larger gear size. When using a modulus system, the number of teeth can be determined by dividing by the modulus to determine the size of the gear.

These attributes are important parameters to consider when customizing spur gears. Based on specific application requirements and design requirements, determining the values of these attributes will help manufacturers or mechanical engineers provide customized spur gears for you.