A hot screw-conveyor hanger bearing is usually a symptom of friction caused by misalignment, worn coupling components, unsuitable bearing material or operating conditions outside the bearing’s intended speed/temperature range. Stop treating temperature alone: inspect the wear pattern, check trough and shaft alignment, confirm the screw is not rubbing the trough, verify coupling-shaft condition and compare speed/loading with the conveyor design. Lubrication must match the bearing material and OEM practice; some dry or hard-faced hanger systems are not intended to be greased.
Find why a hanger bearing runs hot or wears rapidly before the shaft, coupling or screw section fails.
Use bearing temperature trend, noise, wear pattern, shaft marks, alignment, screw-to-trough clearance, motor current, speed/loading and bearing material.
Separate alignment/friction, material-selection, lubrication, overload and structural causes before replacing another bearing.
Fast diagnostic order
- Compare hanger-bearing temperature with adjacent bearings under the same conveyor load.
- Check lubrication history, seal condition, contamination, and visible material ingress.
- Inspect shaft alignment, screw section support, hanger position, and evidence of rubbing.
- Review conveyor loading, plugging history, and any recent maintenance or shaft movement.
- After correction, verify stable temperature, smooth rotation, and normal motor current.
Capture the failure pattern before disassembly
Record: which hanger is hot; surface temperature trend relative to other hangers; motor current and throughput; screw speed; noise or squeal; visible trough rubbing; product temperature; runtime since last bearing replacement; lubrication history; bearing material/style; and whether the same location repeatedly fails. After lockout and safe opening, photograph the bearing, coupling shaft and nearby flights before cleaning them.
Uneven wear on one side of a plain hanger bearing is strong evidence that the shaft is being forced off-center. Uniform wear at every hanger points more toward material selection, speed/loading or system-wide alignment.
1. Verify trough, hanger and shaft alignment
Misalignment is one of the most important causes of premature hanger-bearing wear. The hanger supports the coupling shaft between screw sections; if the trough or hanger position forces that shaft sideways, each revolution creates continuous sliding load and heat. Check that trough sections are straight, level where required by design and correctly supported. Inspect flange joints for steps, twist or distortion. Confirm the hanger is centered and not pulled out of position by overtightened or misfitted hardware.
Do not align only by looking at the trough shell. The rotating centerline through drive shaft, screw sections, coupling shafts, hangers and tail shaft must be considered as a system.
2. Inspect the coupling shaft and bearing as a wear pair
A new bearing installed on a deeply worn, scored or tapered coupling shaft may overheat immediately because contact is poor and load is concentrated. Measure or compare shaft wear against the component manufacturer’s replacement criterion. Look for scoring, galling, discoloration, grooves and eccentric wear. Replace damaged mating components together when the wear pattern shows they have become an incompatible pair.
3. Check for screw deflection or trough contact
Long screw sections can deflect under load. If a flight rubs the trough near the hanger, friction and bending load can be transmitted into the coupling and bearing. Look for polished metal, fresh scraping, unusual dust patterns and recurring noise at the same angular position. Excessive trough loading or an unsuitable screw section length can aggravate deflection. Verify the conveyor’s original design rather than correcting only the bearing.
4. Confirm the bearing material suits cement, speed and temperature
Hanger bearings are available in different materials because abrasiveness, temperature and lubrication conditions vary widely. Cement and mineral dust are abrasive; dust entering the bearing interface can act as grinding media. Check the installed material against the conveyor OEM or component supplier’s recommendation for the actual product, shaft speed and process temperature. A bearing that is satisfactory in a cool, clean powder may fail quickly with hot or highly abrasive material.
5. Verify lubrication practice instead of assuming more grease is better
Some hanger-bearing arrangements are lubricated; others use materials or hard-faced surfaces intended for dry service. Identify the exact bearing type before adding grease or oil. Over-lubrication can attract abrasive cement dust, while under-lubrication will damage a bearing that requires lubricant. Also check the lubrication delivery path: a blocked line, empty lubricator or hardened grease can make a nominally lubricated bearing effectively dry.
6. Correlate heat with speed, loading and motor current
If temperature rises only at high production rates, determine whether the conveyor is being overloaded, overfilled or run above its intended speed. High trough loading increases resistance and can increase shaft deflection. Compare present operating conditions with the conveyor design and with a known-good period. A high motor-current event, repeated start/stop under load or frequent plugging can impose additional torque and bending loads that accelerate hanger and coupling damage.
Hanger-bearing diagnostic matrix
| Evidence pattern | Likely direction | Next action |
|---|---|---|
| One-sided bearing wear | Misalignment | Check trough/hanger centerline and coupling shaft position |
| Bearing hot with scored coupling shaft | Damaged wear pair / lubrication or abrasive ingress | Inspect both components and verify bearing material/lube practice |
| Heat rises with high throughput and motor current | Overload, deflection or internal rubbing | Reduce to normal load and inspect flights/trough contact |
| Several hangers wear rapidly | System-wide design/selection issue | Review speed, material, temperature and full conveyor alignment |
| Recurring failure at same hanger after replacement | Local structural or alignment defect | Inspect supports, trough joint, hanger mount and shaft centerline |
Common repeat-failure mistakes
- Replacing the bearing without checking the coupling shaft.
- Aligning one hanger while leaving the trough or adjacent screw section distorted.
- Adding grease without confirming that the bearing design requires lubrication.
- Ignoring screw-to-trough contact and treating all heat as a bearing defect.
- Returning to full load immediately without comparing temperature and current trends.
Return-to-service verification
After repair, rotate the conveyor safely as required by the OEM and verify no mechanical interference. During commissioning, observe noise, vibration, motor current and hanger temperature trend under no-load and progressively loaded conditions as permitted by site procedure. Acceptance means the repaired hanger does not develop an abnormal temperature rise relative to comparable locations, there is no visible rubbing or unusual noise, motor current remains consistent with the normal operating envelope, and a follow-up inspection shows no new one-sided wear pattern.
Frequently asked troubleshooting questions
What causes screw-conveyor hanger bearings to overheat?
Typical causes include poor lubrication, contamination, misalignment, shaft deflection, rubbing, worn bushings and excessive conveyor load.
Can adding more grease solve a hot hanger bearing?
Not necessarily. Excess grease can also create drag or trap contamination. Verify the bearing design, lubrication method, alignment and material ingress before adding lubricant.
Why do hanger bearings overheat repeatedly after replacement?
Repeated failure usually means the root cause remains—often shaft alignment, conveyor sag, contamination, rubbing or an unsuitable operating load.
Related Infinity technical guides
References
CEMA/Martin Screw Conveyor Safety, Installation, Operation and Maintenance guidance; KWS Manufacturing technical guidance on hanger-bearing wear, alignment, bearing selection and screw-conveyor failures. Use the installed conveyor manufacturer’s component limits and site lockout procedures for final decisions.