The wear of the pinion and gear will increase the backlash in a used unit. If the backlash in the new set is an amount of X, then before replacing a worn or damaged member, the backlash of the gearset should be measured on the outside of the ring gear as shown in Figure 1 (Ref. 1). If it is not possible to measure backlash due to the damage, then the backlash after replacing the damaged member should be adjusted to the maximum of the defined backlash range.
Adjusting the backlash at the time of replacing one member reduces the risk of root interference due to the wear step (see Figure 2) and small flank form changes on the member that is not replaced.
If there is a severe wear step between flanks and root fillet transitions on the member, which is not replaced, then the likelihood of an interference problem still exists. A severe wear step, as shown in Figure 2, can be detected visually or with a drawing pin.
To account for a severe wear step in the root of the undamaged member, the replacement gear must be topland chamfered to prevent interference between the topland corner of the replacement part and the wear step between the flank and root on the teeth of the new member. Topland chamfering is not a widely used standard practice for the case of single-member replacements. The consequence of not applying the service backlash and the topland chamfering is, in many cases, a repeated failure of the unit in question and a costly repeated repair. Topland chamfers, as shown on a pinion (top) and a gear (bottom) in Figure 3, should only have a width of 10 percent of the whole depth of the teeth and an angle that is about 30 degrees to the flank profile at the tip of the teeth. Curved tip roundings are even better than straight chamfers and are recommended if the provision of machining these is available. Rounded top-land corners have advantages over straight chamfers in the case of replacing damaged and worn gears.
(https://www.powertransmission.com)
More about VAFEM:
VAFEM is devoted to providing high quality ball & roller bearings and related transmission parts for domestic and foreign customers in the Vehicle industry and Industries. Our products used in automotive and truck industry mainly include : wheel bearings, wheel bearing kits, wheel hub bearings, alternator bearings, tensioner bearings, clutch bearings, and gear box bearings etc. Our industrial bearings are mainly used in these fields such as Industrial Automation, Home Appliances, Reducers, Agricultural Machines, Precision Machine Spindles, and Transmission Systems etc. As a high-tech company specializing in bearings, we can not only provide stable and trustworthy quality products for OEM customers, but also provide non-standard bearings based on customers’ special requirements. At the same time, we can provide a series of complete product lines and have our own brand VAFEM, it stands for the abbreviation of value added for every movement, which has been recognized by more and more customers and end users.
2026 New Week VAFEM product Recommendation:
A linear-motion bearing or linear slide is a bearing designed to provide free motion in one direction. There are many different types of linear motion bearings. Motorized linear slides such as machine slides, X-Y tables, roller tables and some dovetail slides are bearings moved by drive mechanisms. Not all linear slides are motorized, and non-motorized dovetail slides, ball bearing slides and roller slides provide low-friction linear movement for equipment powered by inertia or by hand. All linear slides provide linear motion based on bearings, whether they are ball bearings, dovetail bearings, linear roller bearings, magnetic or fluid bearings. X-Y tables, linear stages, machine slides and other advanced slides use linear motion bearings to provide movement along both X and Y multiple axis.
2026-03-21