What is meant by backlash and run out in the spur gear?
Spur gear backlash is the amount of tooth space between mating gears at the pitch circle diameter. The purpose of backlash is to allow smooth operation and reduce friction by preventing mating gears from grinding by contact on both sides of their gear teeth at the same time. …
What is the effect of excessive backlash in gear drive?
Gears and Gearboxes It is the distance between the involutes of the mating gear teeth, as illustrated in Figure 39.17. Backlash is necessary to provide the running clearance needed to prevent binding of the mating gears, which can result in heat generation, noise, abnormal wear, overload, and/or failure of the drive.
What causes backlash variation?
Backlash is most commonly created by cutting the teeth deeper into the gears than the ideal depth. The amount of additional material removed when making the gears depends on the pressure angle of the teeth. For a 14.5° pressure angle the extra distance the cutting tool is moved in equals the amount of backlash desired.
What do you understand by backlash in respect of gears?
Backlash, a clearance between mating gear teeth, is built into speed reducers to let the gears mesh without binding and to provide space for a film of lubricating oil between the teeth. This prevents overheating and tooth damage.
What happens if backlash is wrong?
This distance is application-specific* and is critically important on all differentials because insufficient backlash causes the gears to bind, while excessive backlash causes excessive mechanical wear. Note that both inadequate and excessive backlash can cause varying mechanical noises.
How does backlash affect positioning accuracy?
Backlash creates an issue in positioning when an axis changes direction. The slack in the threads/gears cause measureable error in axis positioning. Software backlash compensation can reasonably only compensate for the amount equivalent to the positional accuracy you are required to hold.
What do you understand by backlash in respect of gears How is it measured?
14.1 Definition Of Backlash Backlash is defined in Figure 14-2(a) as the excess thickness of tooth space over the thickness of the mating tooth. There are two basic ways in which backlash arises: tooth thickness is below the zero backlash value; and the operating center distance is greater than the zero backlash value.
How is pinion depth measured?
You must calculate the pinion depth on most OEM gear sets. You can do this by measuring the thickness of the pinion gear head and subtracting that measurement from the factory mounting distance measurement. The end result is your pinion depth.
What do you understand by run out in respect of gears How is it measured?
Runout is the maximum variation of the distance between a surface of revolution and a datum surface, measured perpendicular to that datum surface. Runout of a gear can be measured with a dial indicator over a pin or ball placed in successive tooth spaces.