The head of a cone crusher sits on a spherical bearing to transfer the large axial (vertical) loads generated during crushing to the frame. This bearing consists of the spherical surface under the head (head ball) and the socket on the frame side with its socket liner. Also known on site as the “socket sleeve”, “socket components” or “spherical bearing”, this group is a plain bearing running on an oil film and is one of the most critical load-carrying parts of the crusher.
In this guide we cover in detail the function of the spherical bearing and socket liner, its location in different designs, lubrication requirements, failure signs, inspection and replacement steps, common mistakes and spare part selection. For the general working principle of cone crushers, see our cone crusher guide.
Function of the Spherical Bearing and Socket Liner
- Carries the axial load: The weight of the head and mantle and the vertical component of the crushing force are transferred to the frame through this bearing.
- Allows the gyrating motion: The spherical geometry lets the head slide and turn on the bearing surface while gyrating.
- Takes the wear: The socket liner is a wear part; it wears instead of the main frame and head surfaces.
- Carries the oil film: Oil reaching the bearing surfaces prevents metal-to-metal contact and removes heat.
In some designs the spherical bearing is under the head, in others in the upper area (spider side); in some crushers this function is shared with hydraulically supported thrust bearings. Part names and locations can therefore differ by crusher model.
Material and Design
- Socket liner: Usually made of bronze alloys or steel-backed plain bearing materials. It may contain oil grooves and oil pockets.
- Head ball / spherical surface: Hardened steel; surface quality and sphericity are critical.
- Socket: The carrier part attached to the frame or eccentric assembly; the liner sits inside it and is secured with pins or backing.
Signs of Failure and Wear
- Excessive head spin when idling, or no spin at all: Can indicate that the friction balance in the spherical bearing has been disturbed.
- Rising oil return temperature.
- Increase in bronze (copper, tin, lead) in oil analysis.
- Change in head height: A worn liner can let the head sit lower and change the CSS.
- Metallic noise or vibration.
- Marks found at overhaul: Scoring, smearing (bronze surface smearing by sliding), cracks, pits.
Inspection
| Check | Interval | Method |
|---|---|---|
| Oil return temperature and pressure | Continuous / every shift | Sensors and gauges |
| Oil analysis | Every 250–500 hours | Copper, tin, lead and silicon trends |
| Head spin behaviour | During idle runs | Observation; record sudden changes |
| Contact surface inspection | When the head is removed | Visual after cleaning; contact marking compound |
| Liner thickness and seating | At overhaul | Measurement and seating surface check |
Why Is the Contact Pattern Important?
In the spherical bearing, contact should be spread over a defined area of the surface. If contact is concentrated only at the outer edge or only at the centre, the load is concentrated on a small area; the oil film breaks down and the liner wears rapidly. When a new liner is fitted, checking contact as recommended by the manufacturer and, if necessary, running in the surface by a suitable method are important for long life.
Replacement Steps
- Preparation: The new socket liner, fixing elements, seals and backing material if required are prepared.
- Safe shutdown and disassembly: The crusher is locked out, and the upper group and head group are removed with the manufacturer’s lifting tools (see main shaft and head assembly).
- Removing the old liner: Fixing pins or backing are removed and the liner is taken out; the socket surface is cleaned.
- Inspection: The socket bore, the head’s spherical surface and the oil passages are checked; scoring on the head surface is polished out if necessary.
- Fitting the new liner: The liner is seated fully in its bore and secured; check that the oil grooves are aligned.
- Contact check: Contact is checked by the method described by the manufacturer before or after lowering the head.
- Assembly and commissioning: The head group is lowered into place; oil flow is verified and load is applied gradually while temperatures are monitored.
Common Mistakes
- Running with dirty oil: Dust and metal particles score the bronze surface.
- Not checking the oil passages: A blocked passage leaves the bearing without oil.
- Ignoring scoring on the head surface: The new liner quickly picks up the same marks.
- Applying load with cold oil: Viscous oil does not reach the bearing surface adequately.
- Using an incompatible liner: A difference in spherical radius or thickness distorts the contact pattern.
Troubleshooting Table
| Symptom | Possible cause | Solution |
|---|---|---|
| Rising bronze in oil | Socket liner or bushing wear | Plan an overhaul and inspect the contact surfaces |
| High oil return temperature | Insufficient oil flow, dirty oil, bearing friction | Check the pump, filter and cooler |
| Head spins very fast when idling | Disturbed bearing friction balance | Check bearing and bushing clearances |
| CSS changes by itself | Change in head height due to liner wear | Measure liner thickness and replace if necessary |
| Smearing on the surface | Oil film breakdown, overload | Correct lubrication, reduce load, renew the liner |
An Example from the Field
At a basalt plant, the oil return temperature of a cone crusher kept approaching the alarm limit during the summer months. The cooler fins were cleaned but the problem continued. Oil analysis showed bronze values rising over several samples. When the head was removed during a planned shutdown, smearing was found on the socket liner and one of the oil passages was partly blocked. The liner was renewed, the oil passages were cleaned and oil filtration was improved. Oil temperatures returned to normal.
Spare Part Selection
- Geometry: Spherical radius, thickness and outside diameter must match the crusher model exactly.
- Material: The chemical analysis and hardness of the bronze alloy should be documented.
- Oil grooves: Groove and pocket positions must match the original design.
- Set assessment: When replacing the liner, the head’s spherical surface and related seals should be assessed together.
CSP Mühendislik supplies socket liners, spherical bearing elements and related fixing parts for different cone crusher models as part of its cone crusher spare parts range.
Pre-Purchase Checklist
- Have the crusher model and part number been identified?
- Have the dimensions and wear condition of the existing liner been recorded?
- Has the condition of the head’s spherical surface been inspected?
- Have the requirements for fixing pins, seals and backing material been determined?
Safety
- Removing the head group requires heavy lifting; use the manufacturer’s tools and a lifting plan.
- Do not work until the lubrication and hydraulic systems are depressurised.
Frequently Asked Questions
How long does a socket liner last?
With correct lubrication and clean oil it lasts a long time; the main factors determining its life are oil cleanliness, oil temperature and overload events.
Is it normal for the head to spin when idling?
A certain amount of spin is normal; however, sudden changes in spin speed can indicate a change in bearing or bushing friction and should be investigated.
What if the spherical surface is scored?
Light scoring can be polished out; with deep damage the surface must be machined or the part replaced.
Should the socket liner and eccentric bushing be replaced together?
Not necessarily, but both should be measured during an overhaul; the part closer to its limit should be replaced in the same shutdown.
Spare Parts and Service for the Spherical Bearing and Socket Liner
Through its cone crusher solutions and cone crusher spare parts, CSP Mühendislik quickly supplies socket liners and spherical bearing elements, and supports head group removal, inspection and bearing overhauls with our service team. Send us your crusher model on WhatsApp and we will prepare a quote quickly.
