# What is profile of spur gear?

Table of Contents

## What is profile of spur gear?

In spur gear, the tooth profile starts from the base circle, covers the face and flank region and finally ends at top of the tooth. Forms of teeth: Two curves of any shape that fulfil the law of gearing can be used as the profiles of teeth.

## What is the tooth profile of spur gear called?

Spur gear teeth are manufactured as either involute profile or cycloidal profile.

**How is spur gear tooth size calculated?**

First, you need to define a series of concepts to perform the spur gear calculations:

- The number of teeth (z).
- Module (m).
- Pitch Diameter (d) is the diameter of the pitch circle; its value is: d = m x z.
- Outside Diameter (de) is the diameter of the outside circle; its value is: de = m (z + 2); de = d + 2m.

**How do you calculate gear dental profile?**

Now we have the gear ratio i=d2/d1=z2/z1 (gear 1 is the driving gear, and gear 2 is the driven gear). The module also has to do with the tooth height, for standard gears, the tooth height equals to 2.25*m: addendum ha=1*m, dedendum hf=1.25*m, tooth height h=2.25*m.

### What is lead & profile in gear?

In spur gearing, gear profile is the most sensitive feature. In respect to effects on noise, lead has little to no effect. In helical gearing, lead is the most sensitive featureâ€”with profile, it is second. This is due to the way each type of gear meshes (Figure 3).

### What are the standard tooth profile?

The most common type of gear tooth profile is the involute gear tooth profile, standard and corrected. An involute gear profile means that the profiles of the gear teeth are involutes of a circle, while the involute of a circle is the locus of a point on a piece of string as the string is unwrapped from a circle.

**How do you match teeth with gears?**

To determine the approximate amount of speed change a pair of gears will provide, compare the number of teeth. For example, combining a 32-tooth gear and a 16-tooth gear will change speed at a ratio of 32:16 (or 2:1). Combining a 48-tooth gear and a 12-tooth gear will change speed at a ratio of 4:1.

**What are the standard tooth profiles?**

## How do you determine the number of teeth in a gear with gear ratio?

- Count the number of teeth on each part. In our example, the smaller drive has 21 teeth and the driven has 28 teeth.
- Divide the number of driven gear teeth by the number of drive gear teeth. In our example, it’s 28/21 or 4 : 3.

## What is gear ratio in spur gears?

The ratio of a given pair of spur gears is calculated by dividing the number of teeth on the driven gear, by the number of teeth on the drive gear. The ratio describes the drive gear revolutions needed to turn the driven gear 1 complete revolution.

**What does a 5 2 1 gear ratio mean?**

Gear ratios vary from reel to reel, but they’re all represented in the same manner. Using a gear ratio of 5.2:1, for example, the 1 represents one complete turn, or one revolution (360o) of the handle. For baitcasting reels, the 5.2 represents how many complete times the spool turns with one turn of the handle.