In a cone crusher, motor power is transmitted through the belts and pulley to the countershaft, and from the bevel pinion at the end of the countershaft to the ring gear attached to the eccentric. This power transmission chain consists of the countershaft, countershaft bushings or bearings, pinion, gear and the countershaft box that carries them. Continuous, trouble-free crusher operation depends on this group being correctly lubricated, correctly aligned and running with the correct tooth contact.
In this guide we bring together the function, failure signs, inspection and measurement methods, tooth contact and backlash setting, replacement steps and spare part selection for this group, known on site as the “countershaft”, “countershaft assembly” or “pinion drive gear”. For the general working principle of cone crushers, see our cone crusher guide.
Function and Design of the Countershaft Group
- Countershaft: Transmits the rotation received from the pulley to the pinion. It turns on bushings (plain bearings) or rolling bearings inside the countershaft box.
- Countershaft bushings: Bronze or similar alloy plain bearings; they run on an oil film and take the wear instead of the shaft.
- Pinion: The small bevel gear at the end of the countershaft; drives the ring gear.
- Ring gear: Attached to the eccentric assembly; turns the eccentric.
- Countershaft box and seals: Carry the shaft and prevent oil leakage and dust ingress.
- Oil passages: Deliver oil to the bushings and gears.
For the counterpart of this group on the eccentric side, see our eccentric and eccentric bushing guide.
Why Are Tooth Contact and Backlash Critical?
Bevel gear pairs need a specific backlash and the correct tooth contact pattern to work properly:
- If backlash is too small, the teeth bind, heat up, the oil film breaks down and pitting starts on the tooth surfaces.
- If backlash is too large, the teeth work with impact, noise and vibration increase and there is a risk of tooth breakage.
- The contact pattern should be in the middle of the tooth flank and over a sufficient area. A pattern shifted to the tip, root or edge of the tooth indicates incorrect positioning or wear.
Backlash is set with the shims that determine the position of the ring gear and by the position of the countershaft box. The correct values are given in the manufacturer’s manual.
Signs of Failure and Wear
- Changing gear noise: Whining, clicking or rhythmic knocking.
- Increased vibration: Around the countershaft box.
- Rising iron and bronze in oil analysis: An early indicator of gear and bushing wear.
- Rising temperature at the countershaft box.
- Axial play: The countershaft moving in the axial direction.
- Oil leakage: From the countershaft seals.
- Belt problems at the pulley: Belt misalignment places extra load on the countershaft bearings.
Inspection and Measurement
| Check | Interval | Method |
|---|---|---|
| Noise and vibration | Every shift | Listening, handheld vibration meter |
| Countershaft box temperature | Every shift | Infrared thermometer or sensor |
| Oil analysis | Every 250–500 hours | Tracking iron, copper, tin and silicon |
| Belt tension and pulley alignment | Weekly | Tension meter, laser or straight edge |
| Axial play | At liner changes | Dial indicator |
| Backlash and tooth contact | At overhaul and gear replacement | Feeler gauge/lead wire and contact pattern test with marking compound |
| Bushing clearances | At overhaul | Micrometer and bore measurement |
Maintenance Practices
- Oil cleanliness: Countershaft bushings and gears are very sensitive to dirty oil. Filter changes and oil analysis must be done regularly. See the lubrication unit guide.
- Belt and pulley maintenance: Over-tensioned belts load the countershaft bushings; loose belts cause slipping and shock.
- Seal checks: Dust ingress accelerates bushing and gear wear.
- Cold starts: Do not apply load before the oil reaches the recommended temperature.
Countershaft and Pinion Replacement Step by Step
- Preparation: The new countershaft, bushings or bearings, pinion (usually as a set with the gear), seals and shims are prepared.
- Safe shutdown: The crusher is locked out, the lubrication unit is stopped and the oil is drained.
- Removing the pulley and belts.
- Removing the countershaft box: The box is withdrawn from the frame together with the shaft and pinion; the existing shims are recorded.
- Disassembly and inspection in the workshop: Bushings, shaft surfaces, pinion teeth and box bores are measured.
- Assembly: New bushings are fitted by a suitable method (interference fit, by cooling or heating); the pinion is mounted on the shaft.
- Installation and adjustment: The box is refitted; backlash is set with shims and the contact pattern is verified with a marking test.
- Commissioning: The oil is filled and the crusher is run idle; noise, temperature and vibration are monitored, and oil and filters are checked after the first hours.
Why Should the Pinion and Gear Be Replaced as a Set?
Bevel gear pairs wear together and “run in” to each other. Fitting a new pinion to a worn gear can disturb the contact pattern, cause noise and make the new pinion wear quickly. Most manufacturers therefore recommend replacing the pinion and gear as a matched set. If the gear is still in good condition and the manufacturer allows it, the pinion alone can be replaced; however, the contact pattern must be checked.
Common Mistakes
- Assembling without measuring backlash: Assuming the shims stay the same as before leads to incorrect clearance with new parts.
- Replacing only the pinion: Incompatibility with a worn gear.
- Over-tensioning the belts: Early wear of the countershaft bushings.
- Neglecting oil analysis: Bushing seizure can happen before a bronze increase is noticed.
- Incompatible aftermarket parts: Parts with different tooth module, pressure angle or bushing tolerance.
Troubleshooting Table
| Symptom | Possible cause | Solution |
|---|---|---|
| Gear whine increasing | Tooth wear, wrong backlash, oil problem | Check backlash and contact pattern, carry out oil analysis |
| Rhythmic knocking | Broken/cracked tooth, excessive clearance | Stop immediately and inspect the gears |
| Countershaft box overheating | Bushing wear, insufficient oil, excessive belt tension | Check oil flow and belts; measure bushing clearance |
| Rising bronze in oil | Countershaft or eccentric bushing wear | Plan an overhaul |
| Oil leak from the seal | Seal wear, blocked breather | Check the seal and breather |
An Example from the Field
At an aggregate plant, the gear noise of a cone crusher increased markedly within a few weeks. Oil analysis showed a rise in iron. At the overhaul, pitting was found on the pinion teeth and the contact pattern on the ring gear had shifted to one edge of the tooth. During an earlier repair only the pinion had been replaced and the shims had been left at their old values. The pinion and gear were renewed as a set, backlash was readjusted and the contact pattern was verified with a marking test. The noise returned to normal and iron values remained stable in subsequent oil analyses.
Spare Part Selection
- Gear geometry: Module, number of teeth, pressure angle and helix direction must match exactly.
- Material and surface hardening: The quality of carburising or induction hardening determines tooth life.
- Bushing tolerances: Inside and outside diameter tolerances and oil groove positions must be correct.
- Matched set: Supplying the pinion and gear as a matched set is preferred.
- Documentation: Request a material certificate and dimensional report.
CSP Mühendislik supplies countershafts, countershaft bushings, pinion-gear sets, countershaft box seals and pulleys as part of its cone crusher spare parts range. During an overhaul we recommend also assessing the eccentric bushing and lubrication unit parts.
Pre-Purchase Checklist
- Have the crusher model, serial number and gear part numbers been identified?
- Will the pinion be replaced alone or as a set with the gear?
- Have dimensions been taken for the countershaft bushings or bearings?
- Have the seal set and shims been added to the order?
- Is service support needed for assembly and backlash setting?
Safety
- The countershaft box and gears are heavy; use suitable lifting equipment.
- Any work involving removal of belt and pulley guards must be under LOTO.
- Use suitable gloves and equipment against burns when assembling with heat.
Frequently Asked Questions
When should the countershaft bushing be replaced?
When the measured clearance reaches the manufacturer’s limit, when scoring or seizure marks appear on the surface, or when oil analysis shows a marked increase in bronze.
Is a countershaft on rolling bearings better?
Some modern designs use rolling bearings and others bushings. Both last a long time with correct lubrication and alignment; the choice depends on the crusher design.
What should the backlash be?
It varies by crusher model and gear size; the exact value is given in the manufacturer’s manual.
Is gear noise always a failure?
A certain running noise is normal; what matters is a change in its character. Changing noise, vibration and oil analysis should be assessed together.
Can the pinion be turned around and reused?
Bevel pinions are usually designed for one-way contact; in most designs they cannot be reversed and reused.
Spare Parts and Service for the Countershaft and Pinion
Through its cone crusher solutions and cone crusher spare parts supply, CSP Mühendislik quickly provides countershafts, bushings and pinion-gear sets, and supports countershaft box overhauls and backlash setting on site with our service team. Share your crusher model on WhatsApp for a quick quote.
