Split gearing, another method, consists of two gear halves positioned side-by-side. Half is fixed to a shaft while springs cause the spouse to rotate slightly. This increases the effective tooth thickness so that it totally fills the tooth space of the mating gear, thereby eliminating backlash. In another version, an assembler bolts the rotated fifty percent to the fixed half after assembly. Split gearing is generally used in light-load, low-speed applications.
The simplest and most common way to reduce backlash in a set of gears is to shorten the length between their centers. This movements the gears right into a tighter mesh with low or also zero clearance between the teeth. It eliminates the effect of variations in center distance, tooth dimensions, and bearing eccentricities. To shorten the center distance, either modify the gears to a set range and lock them in place (with bolts) or spring-load one against the other so they stay tightly meshed.
Fixed assemblies are typically used in heavyload applications where reducers must reverse their direction of rotation (bi-directional). Though “fixed,” they could still require readjusting during support to pay for tooth use. Bevel, spur, helical, and worm gears lend themselves to fixed applications. Spring-loaded assemblies, however, maintain a continuous zero backlash and are generally used for low-torque applications.
Common design methods include brief center distance, spring-loaded split gears, plastic-type material fillers, tapered gears, preloaded gear zero backlash gearbox trains, and dual path gear trains.
Precision reducers typically limit backlash to about 2 deg and so are used in applications such as instrumentation. Higher precision models that achieve near-zero backlash are used in applications such as robotic systems and machine tool spindles.
Gear designs can be modified in many methods to cut backlash. Some methods modify the gears to a established tooth clearance during initial assembly. With this process, backlash eventually increases due to wear, which needs readjustment. Other designs use springs to hold meshing gears at a constant backlash level throughout their service life. They’re generally limited to light load applications, though.