# Problems with spur gears and max addendum

• CptJackWest
In summary, spur gears tend to create noise and vibration, leading to wear and tear and potentially failure. The max addendum, which determines the distance between the pitch circle and gear tooth tip, is important to prevent interference and damage. Proper lubrication, gear quality, and alignment can prevent problems with spur gears, but using alternative types of gears, such as helical or herringbone, can also reduce noise and vibration. Factors such as number of teeth, module, and pitch circle diameter can affect the max addendum value. Other gear alternatives include bevel and worm gears, each with their own advantages and disadvantages. Careful consideration of the application is necessary when selecting a gear type.
CptJackWest

## Homework Statement

Consider a gear set with the following attributes:

• A pinion base radius of 11mm
• A centre distance of 73mm
• A pressure angle of 24 degrees
• A module of 5.8mm
What is the maximum addendum radius (mm) that the pinion can have to avoid interference?

## Homework Equations

ramax=√rb2+c2*sin(θ)2

rb= base circle radius of the same member
c= center distance
θ=pressure angle

## The Attempt at a Solution

ramax=√rb2+c2*sin(θ)2
ramax=√0.0112+0.0732*sin(24)2
ramax= 0.0316mm

So that is the answer that I got but I was not sure if you need to use the module for anything or whether it is just extra info
cheers
Jack

Hello Jack,

Your solution is correct. The module is not needed in this calculation as it is used to determine the size of the teeth on the gear, but not the maximum addendum radius. The pressure angle and center distance are the key factors in determining the maximum addendum radius for non-interfering gears.

Hope this helps!
- Scientist

## 1. What is the main problem with using spur gears?

The main problem with using spur gears is that they tend to create a lot of noise and vibration during operation. This can lead to wear and tear on the gears and other components, resulting in reduced performance and potentially even failure.

## 2. What is the significance of the max addendum in spur gears?

The max addendum is the maximum allowable distance between the pitch circle and the tip of the gear tooth. This distance is important because if it is too large, it can lead to interference between the gear teeth, causing jamming or damage to the gears.

## 3. How can problems with spur gears be prevented?

Some common methods to prevent problems with spur gears include proper lubrication, using high-quality gears, and ensuring proper alignment and clearance between gears. Additionally, using helical or herringbone gears instead of spur gears can also help reduce noise and vibration.

## 4. What factors can affect the max addendum in spur gears?

The max addendum in spur gears can be affected by factors such as the number of teeth, the module or diametral pitch of the gears, and the pitch circle diameter. Changes in any of these parameters can result in a different max addendum value.

## 5. Are there any alternatives to spur gears?

Yes, there are several alternatives to spur gears that can be used in different applications. Some common alternatives include helical gears, herringbone gears, bevel gears, and worm gears. Each of these types of gears has its own advantages and disadvantages, so it is important to carefully consider the specific requirements of the application before selecting a gear type.

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