Proč se zemědělské ozubené kolo opotřebovává nerovnoměrně na jedné straně?

When mating gear shafts are not parallel (for spur and helical gears) or not at the correct angle (for bevel gears), the tooth contact zone shifts to one end of the tooth face width. This produces concentrated wear at one end of each tooth — wear that appears heavier on one side of the tooth width rather than distributed across the full face. On helical gears, misalignment also produces a characteristic end-loading pattern where one end of every tooth is worn while the other end shows no wear. Diagnosis: check shaft alignment using a straight edge or dial indicator. Remedy: realign shafts and, if housing bores have been distorted by previous misalignment damage, reline or replace the housing.

Insufficient backlash between mating teeth causes the tooth flanks on the tight side to contact under the thermal expansion that occurs during operation, even when the mesh appears correct at ambient temperature. The tight side carries higher-than-designed load, producing faster wear on that flank. On bevel gears, too-tight backlash typically shows as heavy contact on the tooth tip and toe rather than the central flank area. Diagnosis: measure backlash with a dial indicator; compare to the specification in the service manual. Remedy: increase backlash to specification by adjusting bearing preload or shim pack.

Agricultural gear drives that operate only in one direction — a seeder ground drive, a harvester head drive, a mower counter-shaft — load only one flank of each tooth throughout the gear’s service life. This is not a fault; it is the expected result of design. The drive flank wears while the coast flank remains unworn. This produces apparent “one-sided” wear that is symmetric wear on the correct flank in context. Diagnosis: confirm that the drive is unidirectional. If so, this is normal — replace the gear when the drive flank reaches the end-of-life wear criteria, not based on the appearance of asymmetry alone.

If abrasive contamination — soil, grit, chaff — enters the gear mesh from one direction, it causes preferential abrasive wear on the leading flank of the approaching tooth. This is most common in open (unenclosed) gear drives on seeder metering mechanisms, grain auger drives, and similar applications where soil and crop debris can reach the mesh. The wear pattern is on the flank facing the contamination source. Diagnosis: inspect the mesh area for contamination pathways. Remedy: improve sealing or shielding, and replace both gears since abrasive wear usually damages both mating components.

Shock loads from intermittent high-torque events — slug feeding in a baler, rock impacts in a rotary cutter, crop blockages in a forage harvester — concentrate impact energy on the tooth flank that is in load-carrying contact at the moment of impact. If these events consistently occur in one rotational direction (e.g., the machine always jams in the forward drive direction), the flank carrying load during forward drive shows fatigue pitting and surface damage while the reverse flank is undamaged. Diagnosis: review operating history for blockage events and their frequency. Remedy: address the root cause of repeat blockages, fit an overload clutch if not already present, and replace the gear pair.