Large Cross Roller Slewing Bearing for Heavy Machinery

A cross roller slewing bearing is two seat rings, one raceway, and a single row of cylindrical rollers set at 90° to each other in strict 1:1 alternation. Because each roller contacts the 90° V-groove at 45°, the same bearing carries axial force, radial force and overturning moment simultaneously — no second row, no separate thrust washer, no additional bearing position.

That single-raceway geometry is why the type is chosen wherever the structure has to stay stiff and the rotation has to stay accurate: stacker-reclaimers, deck cranes, mining equipment, aerial platforms, positioners and machine tools. It is also why it demands more from the mounting interface than a ball type does — a point this page addresses directly, because most field problems with cross roller bearings originate at the bolted joint, not in the raceway.

Structure and load path

Element	Description
Rings	Two seat rings, split at the raceway centre plane; not separable after assembly
Rolling element	Cylindrical rollers, hardened and ground, arranged 1:1 at 90°
Contact	Line contact at 45° contact angle on a single 90° V-groove
Load capacity	Axial, radial and tilting moment simultaneously
Retention	Spacers or a segmented cage keep roller spacing and prevent skew

Because the rollers are in line contact rather than point contact, the elastic deformation under load is small and the load is spread over a long raceway length. The practical consequences:

• High tilting stiffness. Deflection at the flange or mast is roughly an order of magnitude lower than a four-point contact ball of comparable diameter, which is what keeps a crane jib level or a positioner square under load.
• Compact axial height. All three load components are handled in one raceway plane, so the bearing is short relative to its diameter — valuable where the structure above cannot be raised.
• Low and predictable starting torque. When correctly preloaded and lubricated, breakaway torque is stable, which matters for servo-driven indexing tables.
• Not for continuous high-speed rotation. Line contact plus crossed geometry means higher friction than a ball bearing; these are positioning bearings, not gearbox bearings.

Selection: cross roller vs the alternatives

	Cross roller	Four-point contact ball	Three-row roller
Contact type	Line, 45°	Point, 45° (or 35°/45° pairs)	Line, dedicated rows
Tilting stiffness	High	Medium	High
Axial capacity	High	High	Very high
Radial capacity	High	Low to medium	High
Axial height	Lowest	Low	Highest
Friction torque	Medium	Low	High
Raceway clearance	Can be set near zero, even preloaded	Small clearance typical	Clearance per row
Sensitivity to mounting flatness	High	Medium	Medium
Best fit	Crane slews, positioners, mining, machine tools, platforms	General rotation, wind pitch/yaw, light structures	Heavy vertical loads, large excavators, ladle turrets

Rule of thumb: if the structure deflects visibly under load and the customer is fighting it, specify cross roller. If the load is dominated by axial force with a light structure, a four-point contact ball will be cheaper and more forgiving.

Mounting accuracy — where these bearings actually fail

A cross roller bearing has a single raceway shared by both rings. Any distortion of the mounting flange is transmitted directly into that raceway as a clearance variation, an edge load, or a localised overload. Three items decide the outcome:

1. Mounting surface flatness. The flange must be machined, not flame-cut and shimmed. Flatness is normally specified per unit diameter (for example 0.1 mm over the full bolted circle for mid-size units); the exact figure is on the drawing and should be measured, not assumed.

2. Bolt preload. Bolts are sized to keep the joint closed under the full overturning moment — the bearing must never see the moment through a gap. Use the specified torque, in the specified sequence, in at least two passes, with hardened washers. Thread engagement and bolt grade are part of the calculation, not a workshop decision.

3. Concentricity and runout check after assembly. Measure gear runout (if geared) and ring radial/axial runout with the bolts final-torqued. A bearing that turns freely on the bench and binds after bolting down is telling you the flange is not flat.

Supply the mating structure dimensions with the order and the bearing can be checked against the actual interface rather than a nominal drawing.

Gear configurations

Prefix	Configuration	Typical use
110	No gear, plain raceway	Direct-drive slews, positioners, idler turntables
111	External gear, standard tooth section	Slewing drives with pinion outside the ring
112	External gear, heavy tooth section	Higher tangential load, larger drives
113	Internal gear, standard tooth section	Compact envelopes, protected tooth mesh
114	Internal gear, heavy tooth section	High torque indexing, mining equipment

Teeth are cut after heat treatment or hard-finished to control distortion, then inspected for profile, lead, single and cumulative pitch error, and backlash against the mating pinion drawing.

Standard size range

Raceway centre diameter D₀ from 500 mm to 4,500 mm. All five prefixes are available at every size listed; sizes beyond this table are built to drawing.

D₀ (mm)	Series	110 no gear	111 ext.	112 ext. heavy	113 int.	114 int. heavy
500	25	110.25.500	111.25.500	112.25.500	113.25.500	114.25.500
560	25	110.25.560	111.25.560	112.25.560	113.25.560	114.25.560
630	25	110.25.630	111.25.630	112.25.630	113.25.630	114.25.630
710	25	110.25.710	111.25.710	112.25.710	113.25.710	114.25.710
800	30	110.30.800	111.30.800	112.30.800	113.30.800	114.30.800
900	30	110.30.900	111.30.900	112.30.900	113.30.900	114.30.900
1000	30	110.30.1000	111.30.1000	112.30.1000	113.30.1000	114.30.1000
1120	30	110.30.1120	111.30.1120	112.30.1120	113.30.1120	114.30.1120
1250	40	110.40.1250	111.40.1250	112.40.1250	113.40.1250	114.40.1250
1400	40	110.40.1400	111.40.1400	112.40.1400	113.40.1400	114.40.1400
1600	40	110.40.1600	111.40.1600	112.40.1600	113.40.1600	114.40.1600
1800	40	110.40.1800	111.40.1800	112.40.1800	113.40.1800	114.40.1800
2000	50	110.50.2000	111.50.2000	112.50.2000	113.50.2000	114.50.2000
2240	50	110.50.2240	111.50.2240	112.50.2240	113.50.2240	114.50.2240
2500	50	110.50.2500	111.50.2500	112.50.2500	113.50.2500	114.50.2500
2800	50	110.50.2800	111.50.2800	112.50.2800	113.50.2800	114.50.2800
3150	60	110.60.3150	111.60.3150	112.60.3150	113.60.3150	114.60.3150
3550	60	110.60.3550	111.60.3550	112.60.3550	113.60.3550	114.60.3550
4000	60	110.60.4000	111.60.4000	112.60.4000	113.60.4000	114.60.4000
4500	60	110.60.4500	111.60.4500	112.60.4500	113.60.4500	114.60.4500

Reading the designation: the three-digit prefix is the structure code (see gear table above), the middle group is the section size series — larger number, deeper section and heavier roller — and the last group is the raceway centre diameter in millimetres. A 110.40.1600 is therefore an ungeared cross roller bearing with a 1,600 mm raceway centre diameter in the 40 size series.

Specification

Final values follow the customer drawing and load case.

Item	Range / value
Type	Single row crossed cylindrical roller slewing bearing
Ring material	50Mn or 42CrMo4 forged ring, per size and load class
Raceway diameter D₀	500–4,500 mm
Overall diameter	Up to approx. 5,000 mm at D₀ 4,500
Raceway hardness	55–62 HRC, induction hardened
Core hardness	50Mn 187–241 HB / 42CrMo 229–269 HB
Rollers	Hardened bearing steel, ground, matched diameter sets, with spacers or segmented cage
Contact angle	45°
Axial / radial clearance	Set per drawing; near-zero or preloaded on request
Gear	None (110), external (111/112), internal (113/114)
Gear accuracy	Inspected to drawing, GB/T 10095 or ISO 1328 equivalent
Seal	Double-lip NBR, purgeable
Lubrication	Lithium-complex grease, or oil for high-duty-cycle applications
Coating	ISO 12944 C3 / C4 / C5-M on request, 240–320 µm DFT
Operating temperature	−30 °C to +60 °C (low-temperature steel on request)
Standards	Customer drawing, JB/T 2300, GB/T 10095 for gearing

Manufacturing and inspection

1. Material — chemistry, grain size and inclusion rating per heat; 100% ultrasonic test of the forging.
2. Ring rolling — circumferential grain flow, UT before machining.
3. Rough machining, quench and temper — hardness survey around the circumference.
4. Raceway induction hardening — surface hardness plus case-depth traverse on a coupon.
5. Raceway grinding — 90° V-groove angle, profile, roundness and roughness verified on a CMM.
6. Crack detection — 100% magnetic particle inspection of both raceway faces.
7. Gear cutting and inspection — profile, lead, pitch, backlash; report issued with the bearing.
8. Roller sorting and assembly — diameter grouping to control clearance, spacer fit checked.
9. Setting and test — clearance measurement, full-rotation torque test, grease quantity by weight.
10. Coating and packing — DFT and adhesion test, VCI wrap, desiccant, seaworthy case.

Documentation package per bearing: material certificates, heat-treatment records, hardness and case-depth report, UT and MPI reports, dimensional report, gear report, torque test record, coating report.

Applications

• Stacker-reclaimers and bucket wheel machines — bucket wheel and boom slews
• Port and shipyard cranes, deck cranes, offshore cranes
• Mining machinery: drills, shovels, conveyors, crusher turntables
• Construction and earth-moving equipment
• Aerial work platforms and scissor lift turntables
• Robotic positioners and welding rotators
• Machine tool rotary tables and indexing tables
• Amusement rides and observation wheels
• Filling, packaging and labelling carousels
• Solar tracker and heliostat azimuth drives

How to specify in one message

Send these six items and a quotation can be issued without a round of questions:

1. Model number from the table above, or the drawing
2. Load case: axial force, radial force and overturning moment, with duty cycle
3. Gear data if geared: module, number of teeth, internal or external, pinion interface
4. Mounting interface: flange flatness, bolt circle, bolt size and grade
5. Environment: indoor, outdoor, washdown, marine, ambient temperature range
6. Quantity and destination port

If the model is not in the table, send the drawing — non-standard diameters and gear data are routine, not exceptional.

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