Large Slewing Ring Bearing Maintenance For Lifting Equipment

In lifting equipment, the large diameter four point contact ball slewing bearing serves as a joint between the upper structure and the undercarriage, providing a means of 360-degree rotation. Lifting devices typically have a complex load spectrum: the slewing ring bearing can simultaneously handle all combinations of thrust, radial, and tilting moment loading. The use of a slewing ring bearing provides yet another benefit: its shaftless design eliminates the need for a spindle or kingpost. The center of the bearing remains open to allow passage of various hydraulic and control components.

Since the bearing is so critical, careful maintenance is necessary. More than 96% of slewing ring bearing failures are due to surface-originated lubrication problems, contamination, overloading, and improper installation and mounting fits. These surface failures occur much earlier than classical fatigue failures and are less predictable.

Inadequate lubrication is the most common cause of premature bearing failures. In slewing ring bearings, a heavy-duty, extreme pressure grease is required. When lubrication is inadequate, surface damage in the form of roughening or waviness occurs. Later, fine cracks develop, followed by flaking. Failures due to contamination are fairly common. Dirt or other debris within the lubrication system act as an abrasive and accelerate the wear. Usually the bearing raceways are scratched or indented, again leading to fine cracking and, ultimately, spalling.

To get drawing (pdf),please clik on Model.

No	External gear	Dimensions (mm)			Mounting Dimensions (mm)						Structural Dimension (mm)					Gear data					Gear force  10^4 KN		weight            kg
		D	d	H	D1	D2	n	Φ	dm	L	n1	D3	d1	H1	h	b	x	M	De	z	N	T
1	011.20.200.	280	120	60	248	152	12	16	M14	28	2	201	199	50	10	40	0	3	300	98	1.5	2.1	24
2	011.20.224.	304	144	60	272	176	12	16	M14	28	2	225	223	50	10	40	0	3	321	105	1.5	2.1	25
3	011.20.250.	330	170	60	298	202	18	16	M14	28	2	251	249	50	10	40	0	4	352	86	2.1	2.8	30
4	011.20.280.	360	200	60	328	232	18	16	M14	28	2	281	279	50	10	40	0	4	384	94	1.5	2.8	34
5	011.25.315.	408	222	70	372	258	20	18	M16	32	2	316	314	60	10	50	0	5	435	85	2.9	4.4	52
6	011.25.355.	448	262	70	412	298	20	18	M16	32	2	356	354	60	10	50	0	5	475	93	2.9	4.4	59
7	011.25.400.	493	307	70	457	343	20	18	M16	32	2	401	399	60	10	50	0	6	528	86	3.5	5.3	69
8	011.25.450.	543	357	70	507	393	20	18	M16	32	2	451	449	60	10	50	0	6	576	94	3.5	5.3	76
9	011.30.500.	602	398	80	566	434	20	18	M16	32	4	501	499 498	70	10	60	0.5	5	629	123	3.7	5.2	85
	012.25/30.500																	6	628.8	102	4.5	6.2
10	011.30.560.	662	458	80	626	494	20	18	M16	32	4	561	559 558	70	10	60	0.5	5	689	135	3.7	5.2	95
	012.25/30.560																	6	688.8	112	4.5	6.2
11	011.30.630.	732	528	80	696	564	24	18	M16	32	4	631	629 628	70	10	60	0.5	6	772.8	126	4.5	6.2	110
	012.25/30.630																	8	774.4	94	6	8.3/8.2
12	011.30.710.	812	608	80	776	644	24	18	M16	32	4	711	709 708	70	10	60	0.5	6	850.8	139	4.5	6.2	120
	012.25/30.710																	8	854.4	104	6	8.9/8.3
13	011.40.800.	922	678	100	878	722	30	22	M20	40	6	801	798	90	10	80	0.5	8	966.4	118	8	11.1	220
	012.30/40.800																	10	968	94	10	14.1/14
14	011.40.900.	1022	778	100	978	822	30	22	M20	40	6	901	898	90	10	80	0.5	8	1062.4	130	8	11.1	240
	012.30/40.900																	10	1068	104	10	14
15	011.40.1000	1122	878	100	1078	922	36	22	M20	40	6	1001	998	90	10	80	0.5	10	1188	116	10	14	270
	012.30/40.1000																	12	1185.6	96	12	16.7
16	011.40.1120	1242	998	100	1198	1042	36	22	M20	40	6	1121	1118	90	10	80	0.5	10	1298	127	10	14	300
	012.30/40.1120																	12	1305.6	106	12	16.7
17	011.45.1250	1390	1110	110	1337	1163	40	26	M24	48	5	1252	1248	100	10	90	0.5	12	1449.6	118	13.5	18.8	420
	012.35/45.1250																	14	1453.2	101	15.8	21.9
18	011.45.1400	1540	1260	110	1487	1313	40	26	M24	48	5	1402	1398	100	10	90	0.5	12	1605.6	131	13.5	18.8	480
	012.35/45.1400																	14	1607.2	112	15.5	21.9
19	011.45.1600	1740	1460	110	1687	1513	45	26	M24	48	5	1602	1598	100	10	90	0.5	14	1817.2	127	15.8	21.9	550
	012.35/45.1600																	16	1820.8	111	18.1	25
20	011.45.1800	1940	1660	110	1887	1713	45	26	M24	48	5	1801            1802	1798	100	10	90	0.5	14	2013.2	141	15.8	21.9	610
	012.35/45.1800																	16	2012.8	123	18.1	25
21	011.40/60.2000	2178	1825	144	2110	1891	48	33	M30	60	8	2001            2002	1998	132	12	120	0.5	16	2268.8	139	24.1	33.3	1100
	012.40/60.2000																	18	2264.4	123	27.1	37.5
22	011.40/60.2240	2418	2065	144	2350	2131	48	33	M30	60	8	2241            2242	2238	132	12	120	0.5	16	2492.8	153	24.1	33.3	1250
	012.40/60.2240																	18	2498.4	136	27.1	37.5
23	011.40/60.2500	2678	2325	144	2610	2391	56	33	M30	60	8	2501            2502	2498	132	12	120	0.5	18	2768.4	151	27.1	37.5	1400
	012.40/60.2500																	20	2776	136	30.1	41.8
24	011.40/60.2800	2978	2625	144	2910	2691	56	33	M30	60	8	2802	2798	132	12	120	0.5	18	3074.4	168	27.1	37.5	1600
	012.40/60.2800																	20	3076	151	30.1	41.8
25	011.50/75.3150	3376	2922	174	3286	3014	56	45	M42	84	8	3152	3147	162	12	150	0.5	20	3476	171	37.7	52.2	2800
	012.50/75.3150																	22	3471.6	155	41.5	57.4