C93200 Split Bronze Bearing Shells for Conveyor Tail-Pulley Shafts
For C93200 split bronze bearing shells on a conveyor tail-pulley shaft, begin with the existing plain-bearing arrangement, belt-force directions and assembled housing bore. Belt tension difference relates to transmitted torque; it is not the bearing’s radial load. Release replacement halves as a matched geometry with the approved lubrication, retention and installed-clearance requirements.
This guide applies to a conveyor already designed with split metallic journal shells, or to an engineering review explicitly authorised by its designer. Many conveyor pulleys use rolling bearings. A C93200 shell is not a drop-in replacement for a pillow-block ball or roller bearing.
Confirm whether the shaft or pulley shell rotates
| Arrangement | Relative motion to identify | What cannot be assumed |
|---|---|---|
| Pulley fixed to a rotating shaft; external plain journals | The shaft turns inside stationary split shells | The shaft support, cap joint, clearances and lubricant route must follow its drawing. |
| Pulley rotating around a stationary shaft | Bearings are inside the pulley or hubs | An external bearing-shell drawing does not define the internal arrangement. |
| External rolling-bearing housings | Rolling elements support the shaft through specified rings | Housing split lines do not mean the bearing is a split bronze shell. |
| Take-up mounting | The bearing support changes position for tension adjustment | Alignment and retention must remain correct throughout the adjustment range. |
Rulmeca’s pulley catalogue distinguishes pulley positions and shaft arrangements, and describes rolling-bearing housings as standard for its range. Its belt-load design inputs are useful application context, not evidence that Rulmeca uses the C93200 plain shells discussed here.
[1]Use belt-force vectors to obtain journal reactions
The bearing reaction comes from the force and moment balance of the pulley and shaft. Include both belt-span tension directions, pulley weight, support locations and any additional loads. For an idealised non-driven tail pulley with nearly 180° belt wrap, the two forces exerted by the outgoing belt spans can act almost parallel on the pulley. Their radial effects add even if their tension difference is small.
In this original illustrative case, assume both belt forces act horizontally in the same direction at 6 kN each. Place the pulley centrally between two identical ideal supports, with total centred pulley/shaft weight 1 kN acting vertically. Omit impact, belt transients, misalignment and all other loads.
| Quantity | Calculation | Result |
|---|---|---|
| Horizontal belt resultant | 6 + 6 | 12 kN |
| Ideal tension difference | 6 − 6 | 0 kN; does not mean zero bearing load |
| Horizontal reaction per centred support | 12 / 2 | 6 kN |
| Vertical reaction per centred support | 1 / 2 | 0.5 kN |
| Resultant per support | √(6² + 0.5²) | About 6.02 kN |
These are assumed loads, not allowable C93200 reactions. They illustrate a force-balance error to avoid. For different span directions, combine vectors rather than adding scalar magnitudes. An overhung or off-centre pulley changes reaction sharing; evaluate actual dimensions and all relevant operating and start-up cases.
The plain journal then needs its own contact, speed, lubricant-film and heat review. A nominal projected-pressure calculation using reaction divided by journal diameter times loaded length is a screening quantity. It does not resolve shaft bending or concentrated edge contact.
Keep alloy acceptance separate from shell duty
Concast identifies C93200 as a leaded tin-bronze casting alloy and lists bearing and bushing applications. Its sheet references ASTM B505/B505M-23 for the stated material data. Those data describe the material and condition, not an allowable conveyor operating envelope.
[2]State the exact alloy, product standard and edition, casting route, condition and required traceability. If an order uses the historical SAE 660 purchasing name, confirm the intended current alloy and acceptance specification. Do not automatically translate RG7 or another European bronze into C93200.
Availability of a particular split geometry and alloy is reviewed for the enquiry. Do not infer dry-running capability from the bronze name or add graphite plugs to replace the existing lubrication system without engineering approval.
Control the two halves in their assembled housing
Show the shell split plane, locating shoulders, anti-rotation features, joint-face geometry, lubricant feed and grooves on the same approved drawing. Identify the mating upper and lower halves and keep their orientation traceable. A photograph of two semicircles cannot establish the assembled bore.
Specify the condition in which the bore is inspected: the correct housing, matched cap, approved fasteners and defined assembly procedure. Do not invent an automotive-style shell crush, a universal interference or a cap torque. Thick machined bronze halves and thin lined shells can use different locating principles.
Inspect the housing seat and joint faces for distortion, fretting, burrs and previous repair. Avoid filing shell joints or adding shims to remove clearance unless the original bearing design permits that operation. Such changes can alter the circularity, seating and lubricant clearance.
Measure shaft diameter, ovality, taper, surface condition and straightness at both journals. A new round shell may still contact a worn or bending shaft unevenly. Record any permitted axial movement separately from the radial running clearance.
Preserve the oil route and take-up alignment
Retain the specified lubricant, feed location and groove design. Check that the assembled halves do not obstruct a passage and that seals, end clearances and return paths work as designed. Groove location must be evaluated against the real load sector, not chosen by appearance.
Inspect the arrangement throughout take-up adjustment. The two supports must remain aligned with the shaft and pulley geometry; tightening the bearing cap cannot correct skewed take-up slides. Include contamination exclusion for conveyed dust, water and cleaning conditions, with an inspection route for blocked feeds.
Before batch release, agree assembled-bore inspection, part identification, lubricant-path verification and the equipment owner’s functional checks. Establish acceptable temperature, movement, leakage and wear observations through the approved commissioning procedure. The material report alone cannot prove pulley alignment or conveyor reliability.
Frequently asked questions
Can C93200 replace a rolling bearing in a conveyor housing?
This guide establishes no such substitution. Keep the specified bearing architecture unless the designer approves a complete review of support, speed, sealing, lubrication and alignment.
Is T1 minus T2 the load on the plain bearing?
No. The support reactions depend on the vector sum of belt forces, weight and other loads with their positions. The tension difference alone can hide a large radial load.
Can one damaged half be replaced independently?
Follow the original replacement and inspection specification. The two halves form an assembled bore, so their geometry, identification and seating must be checked together.
Can graphite plugs solve an oil-feed failure?
They do not restore the designed feed. Investigate the lubrication fault and obtain approval before changing the bearing construction.
Request a drawing review
Send the pulley and shaft arrangement, existing shell and housing drawings, exact grade, matched-half identification, assembly procedure, journal measurements, belt tensions and directions, support spacing, weight, speed, take-up travel, lubrication, environment, quantity and inspection requirements.
Send your drawing for review or email sales@boniubushing.com. BONIU confirms manufacturing feasibility, material availability, documentation and quotation scope for the specific enquiry. This guide is not a stock listing or a record of BONIU testing for the illustrated application.
Technical references
- Rulmeca: pulleys for belt conveyors, general catalogue. Pulley design inputs, belt tensions and alternative shaft/bearing arrangements. Its standard rolling-bearing designs are not approval for bronze-shell conversion.
- Wieland Concast: C93200 producer sheet. Leaded tin-bronze material identity and product-standard reference; not a conveyor bearing rating.
Source descriptions and proprietary product data belong to the cited organisations. They are not BONIU ratings, certifications or test results. Calculations and application checklists in this article are engineering analysis under the stated assumptions. Confirm the supplied part and complete assembly against the approved drawing.