When manufacturing gears, you have to think about backlash. No, we’re not talking about a wave of people who vocally disagree with the gear manufacturing process or retaliation for some kind of event. In the engineering world, backlash refers to both a naturally occurring error in motion when gears move, and the gap between gears responsible for that error.
Defining Backlash
Gear systems don’t always change direction, but when they do, backlash becomes possible. There’s always a bit of a gap that forms between the trailing face of the gear tooth carrying the force forward and the leading face of the tooth immediately behind it; this gap has to be closed before the gears can reverse momentum. “Backlash” refers both to this gap specifically and the general problem with the error of motion.
Why Backlash Is Important
If a set of gears were to have “zero” backlash, it would mean the gears have been absolutely perfectly designed and manufactured, with no lubricant between them, and no thermal expansion or retraction interfering with the system. This simply isn’t realistic, so all gear systems must be designed with backlash in mind—especially ones that require more precision and control.
How We Minimize Backlash
For systems that require as little backlash as possible, we minimize backlash through a number of techniques. Some of these include splitting the gear on a plane perpendicular to its axis, then using the two halves in conjunction with one another with springs to add torque to the system. This produces a multi-gear system that functions almost like a single gear with expanding teeth. You can also taper teeth in the axial direction and let the gear slide in the same direction to take up the slack.
Backlash may have an unexpected name, but it’s an important phenomenon to plan for in the gear manufacturing world. If you’re interested in getting a gear manufacturing quote, or want to learn more about the gear making process, be sure to contact us.