Sky Bearings

XTSKY BEARING

>>　Manufacturing process

>>　Bearing Material

>>　Tolerance

>>　Clearance

>>　Vibration & Noise

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※　Manufacturing process

※　Bearing Material

Rings(cups & cones) & Rolling elements
XTSKY bearing rings(cups & cones), balls & rollers are made of GCr15 high carbon chromium bearing steel
This steel No. is equal to the AISI 52100(U.S.A.), DIN 100Cr6(Germany), JIS SUJ2(Japan) etc.

Chemical composition of GCr15 steel:

Steel No.	Chemical composition %
GCr 15	C	Si	Mn	P	S	Cr	Mo	Cu	Ni
GCr 15	0.95-1.05	0.15-0.35	0.25-0.45	≤0.027	≤0.02	1.40-1.65	-	≤0.25	≤0.30

Contrast of steel no. in different countries

Country	China	ISO	U.S.A.	Japan	Germany	France	Sweden
Standard	GB		AISI	JIS	DIN	NF
Steel No.	GCr15	683/XVLL1	52100	SUJ2	100Cr6	100C6	SKF3

Hardness
Hardness of bearing rings(cups & cones) & rolling elements is HRC60～HRC65.

Retainers
XTSKY standard bearing retainers are made from cold rolled carbon steel. However, in cases of heavy duty, corrosive environment,misalignment and high speed operation, brass, stainless steel, nylon or phenolic resins will be used upon request.

Seals & Shields
XTSKY shields also employ carbon steel as standard.
Buna Nitrile is the standard and mostly common used material for XTSKY seals. Also, in order to meet the requirements of high temperature operation and compatibility with grease, a variety of other sealing materials are also applied to the seals.

Lubrication
Standard grease and oil are applied to XTSKY bearing products
XTSKY can also use special pointed brand grease or oil upon request

※　Tolerance

XTSKY bearing tolerance standard accords with Chinese national standard GB/T307(equal to ISO492)
The following are the contrast tables of Chinese national standard with the foreign standards.

Contrast of tolerance class for radial bearings in different countries(except tapered roller bearing)

Country	Standard	Tolerance class
China	GB/T307	0 (G)	6 (E)	5 (D)	4 (C)	2 (B)
ISO	ISO492	0	6	5	4	2
Sweden	SKF	0	P6	P5	P4	P2
Germany	DIN 620/2	P0	P6	P5	P4	P2
U.S.A.	ANSI B3.14	ABEC1	ABEC3	ABEC5	ABEC7	ABEC9
Japan	JIS B1514	0	6	5	4	2

Contrast of tolerance class for tapered roller bearing(metric size) in different countries

Country	Standard	Tolerance class
China	GB/T307	0	P6x		P5	P4
ISO	ISO492	0	6x		5	4
Sweden	SKF	0	CLN		P5
U.S.A.	ANSI	K		N	C	B	A
Japan	JIS	0	6x	6	5	4

Contrast of tolerance class for tapered roller bearing(inch size) in different countries

Country	Standard	Tolerance class
China	XTSKY	4		3
ISO	ISO492	4		3	0	00
Sweden	SKF	0		CL3	CL0
U.S.A.	ANSI	4	2	3	0	00

The standard manufacturing tolerance of XTSKY bearing is Class 0. Other tolerance grade can be supplied upon request

Tolerance of Class 0 radial bearing

Inner ring

d		△dmp		Vdp			Vdmp	△Bs		△B1s		VBs	Kia
over	incl.	high	low	Dimension series			max	high	low	high	low	max	max
mm		µm		8, 9	0, 1	2, 3, 4	µm	µm		µm		µm	µm
mm		µm		max (µm)			µm	µm		µm		µm	µm
2.5	10	0	-8	10	8	6	6	0	-120	0	-250	15	10
10	18	0	-8	10	8	6	6	0	-120	0	-250	20	10
18	30	0	-10	13	10	8	8	0	-120	0	-250	20	13
30	50	0	-12	15	12	9	9	0	-120	0	-250	20	15
50	80	0	-15	19	19	11	11	0	-150	0	-380	25	20
80	120	0	-20	25	25	15	15	0	-200	0	-380	25	25
120	180	0	-25	31	31	19	19	0	-250	0	-500	30	30
180	250	0	-30	38	38	23	23	0	-300	0	-500	30	40
250	315	0	-35	44	44	26	26	0	-350	0	-500	35	50
315	400	0	-40	50	50	30	30	0	-400	0	-630	40	60
400	500	0	-45	56	56	34	34	0	-450	0	-630	50	65
500	630	0	-50	63	63	38	38	0	-500	0	-800	60	70
630	800	0	-75	-	-	-	-	0	-750	-	-	70	80
800	1000	0	-100	-	-	-	-	0	-1000	-	-	80	90
1000	1250	0	-125	-	-	-	-	0	-1250	-	-	100	100
1250	1600	0	-160	-	-	-	-	0	-1600	-	-	120	120
1600	2000	0	-200	-	-	-	-	0	-2000	-	-	140	140

Outer ring

D		△Dmp		VDp				VDmp	△Cs		△C1s		VCs	Kea
over	incl.	high	low	Dimension series			With oil seals	max	high	low	high	low	max	max
mm		µm		8, 9	0, 1	2, 3, 4	or shields	µm	µm		µm		µm	µm
mm		µm		max (µm)				µm	µm		µm		µm	µm
6	18	0	-8	10	8	6	10	6	same as inner ring △Bs, △B1s, VBs					15
18	30	0	-9	12	9	7	12	7						15
30	50	0	-11	14	11	8	16	8						20
50	80	0	-13	16	13	10	20	10						25
80	120	0	-15	19	19	11	26	11						35
120	150	0	-18	23	23	14	30	14						40
150	180	0	-25	31	31	19	38	19						45
180	250	0	-30	38	38	23	-	23						50
250	315	0	-35	44	44	26	-	26						60
315	400	0	-40	50	50	30	-	30						70
400	500	0	-45	56	56	34	-	34						80
500	630	0	-50	63	63	38	-	38						100
630	800	0	-75	94	94	55	-	55						120
800	1000	0	-100	125	125	75	-	75						140
1000	1250	0	-125	-	-	-	-	-						160
1250	1600	0	-160	-	-	-	-	-						190
1600	2000	0	-200	-	-	-	-	-						220
2000	2500	0	-250	-	-	-	-	-						250

Tolerance of Class 0 tapered roller bearing (metric size)

Cone and width

d		△dmp		Vdp	Vdmp	△Bs		Kia	△Ts		△T1s		△T2s
over	incl.	high	low	max	max	high	low	max	high	low	high	low	high	low
mm		µm		µm	µm	µm		µm	µm		µm		µm
10	18	0	-12	12	9	0	-120	15	+200	0	+100	0	+100	0
18	30	0	-12	12	9	0	-120	18	+200	0	+100	0	+100	0
30	50	0	-12	12	9	0	-120	20	+200	0	+100	0	+100	0
50	80	0	-15	15	11	0	-150	25	+200	0	+100	0	+100	0
80	120	0	-20	20	15	0	-200	30	+200	-200	+100	-100	+100	-100
120	180	0	-25	25	19	0	-250	35	+350	-250	+150	-150	+150	-150
180	250	0	-30	30	23	0	-300	50	+350	-250	+150	-150	+150	-150
250	315	0	-35	35	26	0	-350	60	+350	-250	+150	-150	+150	-150
315	400	0	-40	40	30	0	-400	70	+400	-400	+200	-200	+200	-200
400	500	0	-45	45	34	0	-450	70	+400	-400
500	630	0	-50	50	38	0	-500	85	+500	-500
630	800	0	-75	75	56	0	-750	100	+600	-600
800	1000	0	-100	100	75	0	-1000	120	+750	-750
1000	1250	0	-125			0	-1250	120	+1000	-1000
1250	1600	0	-160			0	-1600	120	+1500	-1500
1600	2000	0	-200			0	-2000	120	+1500	-1500

Cup

D		△Dmp		VDp	VDmp	△Cs		Kea
over	incl.	high	low	max	max	high	low	max
mm		µm		µm	µm	µm		µm
18	30	0	-12	12	9	same as △Bs		18
30	50	0	-14	14	11			20
50	80	0	-16	16	12			25
80	120	0	-18	18	14			35
120	150	0	-20	20	15			40
150	180	0	-25	25	19			45
180	250	0	-30	30	23			50
250	315	0	-35	35	26			60
315	400	0	-40	40	30			70
400	500	0	-45	45	34			80
500	630	0	-50	50	38			100
630	800	0	-75	75	55			120
800	1000	0	-100	100	75			120
1000	1250	0	-125	125	94			120
1250	1600	0	-160	160	120			120
1600	2000	0	-200					120
2000	2500	0	-250					120

Tolerance of Class 4 tapered roller bearing (inch size)

Cone

d		△ds
over	incl.	high	low
mm		µm
-	76.2	+13	0
76.2	101.6	+25	0
101.6	266.7	+25	0
266.7	304.8	+25	0
304.8	609.6	+51	0
609.6	914.4	+76	0
914.4	1219.2	+102	0
1219.2	-	+127	0

Cup

D		△Ds		Kia,Kea,Sia,Sea
over	incl	high	low	max
mm		µm		µm
-	266.7	+25	0	51
266.7	304.8	+25	0	51
304.8	609.6	+51	0	51
609.6	914.4	+76	0	76
914.4	1219.2	+102	0	76
1219.2	-	+127	0	76

Width

d		D		△Ts
over	incl	over	incl	high	low
mm		µm		µm
-	101.6	-	-	+203	0
101.6	266.7	-	-	+356	-254
266.7	304.8	-	-	+356	-254
304.8	609.6	-	508	+381	-381
304.8	609.6	508	-	+381	-381
609.6	-	-	-	+381	-381

Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:12)

d		△dmp		Vdp	△d1mp-△dmp
over	incl	high	low	max	high	low
mm		µm		µm	µm
18	30	+21	0	13	+21	0
30	50	+25	0	15	+25	0
50	80	+30	0	19	+30	0
80	120	+35	0	25	+35	0
120	180	+40	0	31	+40	0
180	250	+46	0	38	+46	0
250	315	+52	0	44	+52	0
315	400	+57	0	50	+57	0
400	500	+63	0	56	+63	0
500	630	+70	0	-	+70	0
630	800	+80	0	-	+80	0
800	1000	+90	0	-	+90	0
1000	1250	+105	0	-	+105	0
1250	1600	+125	0	-	+125	0
1600	2000	+150	0	-	+150	0

Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:30)

d		△dmp		Vdp	△d1mp-△dmp
over	incl	high	low	max	high	low
mm		μm		μm	μm
80	120	+20	0	25	+40	0
120	180	+25	0	31	+50	0
180	250	+30	0	38	+55	0
250	315	+35	0	44	+60	0
315	400	+40	0	50	+65	0
400	500	+45	0	56	+75	0
500	630	+50	0	63	+85	0
630	800	+75	0	－	+100	0
800	1000	+100	0	－	+100	0
1000	1250	+125	0	－	+115	0
1250	1600	+160	0	－	+125	0
1600	2000	+200	0	－	+150	0

※　Clearance

XTSKY bearing radial clearance accords with the Chinese national standard GB/T 4604,
which is equal to ISO 5753

The clearances is classified into 5 groups, C2, C0, C3, C4, C5 with different applications
depending on customer's request

Radial clearance of deep groove ball bearing

d		C2		C0		C3		C4		C5
over	incl.	min.	max	min.	max	min.	max	min.	max	min.	max
mm		μm
2.5	6	1	8	5	15	10	20	15	25	21	33
6	10	2	9	6	17	12	25	19	33	27	42
10	14	2	10	6	19	13	26	21	35	30	48
14	18	3	12	8	21	15	28	23	37	32	50
18	24	4	14	10	23	17	30	25	39	34	52
24	30	5	16	11	24	19	35	29	46	40	58
30	40	6	18	13	29	23	40	34	53	46	66
40	50	6	19	14	31	25	44	37	57	50	71
50	65	7	21	16	36	30	50	45	69	62	88
65	80	8	24	18	40	35	60	54	83	76	108
80	100	9	27	22	48	42	70	64	96	89	124
100	120	10	31	25	56	50	83	75	114	105	145
120	140	10	38	30	68	60	100	90	135	125	175
140	160	15	44	35	80	70	120	110	161	150	210

Radial clearance of cylindrical bore self-aligning ball bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
18	24	7	17	13	26	20	33	28	42	37	55
24	30	9	20	15	28	23	39	33	50	44	62
30	40	12	24	19	35	29	46	40	59	52	72
40	50	14	27	22	39	33	52	45	65	58	79
50	65	18	32	27	47	41	61	56	80	73	99
65	80	23	39	35	57	50	75	69	98	91	123
80	100	29	47	42	68	62	90	84	116	109	144
100	120	35	56	50	81	75	108	100	139	130	170
120	140	40	68	60	98	90	130	120	165	155	205
140	160	45	74	65	110	100	150	140	191	180	240

Radial clearance of tapered bore self-aligning ball bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
-	10	0	25	20	45	35	60	50	75	-	-
10	24	0	25	20	45	35	60	50	75	65	90
24	30	0	25	20	45	35	60	50	75	70	95
30	40	5	30	25	50	45	70	60	85	80	105
40	50	5	35	30	60	50	80	70	100	95	125
50	65	10	40	40	70	60	90	80	110	110	140
65	80	10	45	40	75	65	100	90	125	130	165
80	100	15	50	50	85	75	110	105	140	155	190
100	120	15	55	50	90	85	125	125	165	180	220
120	140	15	60	60	105	100	145	145	190	200	245
140	160	20	70	70	120	115	165	165	215	225	275
160	180	25	75	75	125	120	170	170	220	250	300
180	200	35	90	90	145	140	195	195	250	275	330
200	225	45	105	105	165	160	220	220	280	305	365
225	250	45	110	110	175	170	235	235	300	330	395
250	280	55	125	125	195	190	260	260	330	370	440
280	315	55	130	130	205	200	275	275	350	410	485
315	355	65	145	145	225	225	305	305	385	455	535
355	400	100	190	190	280	280	370	370	460	510	600
400	450	110	210	210	310	310	410	410	510	565	665
450	500	110	220	220	330	330	440	440	550	625	735

Radial clearance of tapered bore spherical roller bearing

d		C2		C0		C3		C4		C5
over	incl	min	max	min	max	min	max	min	max	min	max
mm		μm
14	18	10	20	20	35	35	45	45	60	60	75
18	24	10	20	20	35	35	45	45	60	60	75
24	30	15	25	25	40	40	55	55	75	75	95
30	40	15	30	30	45	45	60	60	80	80	100
40	50	20	35	35	55	55	75	75	100	100	125
50	65	20	40	40	65	65	90	90	120	120	150
65	80	30	50	50	80	80	110	110	145	145	180
80	100	35	60	60	100	100	135	135	180	180	225
100	120	40	75	75	120	120	160	160	210	210	260
120	140	50	95	95	145	145	190	190	240	240	300
140	160	60	110	110	170	170	220	220	280	280	350
160	180	65	120	120	180	180	240	240	310	310	390
180	200	70	130	130	200	200	260	260	340	340	430
200	225	80	140	140	220	220	290	290	380	380	470
225	250	90	150	150	240	240	320	320	420	420	520
250	280	100	170	170	260	260	350	350	460	460	570
280	315	110	190	190	280	280	370	370	500	500	630
315	355	120	200	200	310	310	410	410	550	550	690
355	400	130	220	220	340	340	450	450	600	600	750
400	450	140	240	240	370	370	500	500	660	660	820
450	500	140	260	260	410	410	550	550	720	720	900
500	560	150	280	280	440	440	600	600	780	780	1000
560	630	170	310	310	480	480	650	650	850	850	1100
630	710	190	350	350	530	530	700	700	920	920	1190
710	800	210	390	390	580	580	770	770	1010	1010	1300
800	900	230	430	430	650	650	860	860	1120	1120	1440
900	1000	260	480	480	710	710	930	930	1220	1220	1570

※ Vibration & Noise
Bearing vibration means bearing components' elastic deformation that varies with time and all other
movement that deviates from a theoretic position except that necessary to bearing functions.
It has two modes-acceleration (dB) and velocity (um/s).
Vibration acceleration is examined according to Z, Z1, Z2, Z3 values. Grade Z is fundamental.
Z1, Z2, Z3 successively indicate the vibration level ranging from low to high.
Vibration velocity is examined as per V, V1, V2 and V3. Grade V is fundamental,
V1, V2, V3 successively indicate the vibration level ranging from low to high.

Vibration acceleration limits for single deep groove ball bearing

d	Diameter series (0)				Diameter series (2)				Diameter series (3)
mm	Z	Z1	Z2	Z3	Z	Z1	Z2	Z3	Z	Z1	Z2	Z3
3	35	34	32	28	36	35	32	30	37	36	33	31
4	35	34	32	28	36	35	32	30	37	36	33	31
5	37	36	34	30	38	37	34	32	39	37	35	33
6	37	36	34	30	38	37	34	32	39	37	35	33
7	39	38	35	31	40	38	36	34	-	-	-	-
8	39	38	35	31	40	38	36	34	-	-	-	-
9	41	40	36	32	42	40	37	35	-	-	-	-
10	43	42	38	33	44	42	39	35	46	44	40	37
12	44	43	39	34	45	43	39	35	47	45	40	37
15	45	44	40	35	46	44	41	36	48	46	42	38
17	46	44	40	35	47	45	41	36	49	47	42	38
20	47	45	41	36	48	46	42	38	50	48	43	39
22	47	45	41	36	48	46	42	38	50	48	43	39
25	48	46	42	38	49	47	43	40	51	49	44	41
28	49	47	43	39	50	48	44	41	52	50	45	42
30	49	47	43	39	50	48	44	41	52	50	45	42
32	50	48	44	40	51	49	45	42	53	51	46	43
35	51	49	45	41	52	50	46	43	54	52	47	44
40	53	51	46	42	54	52	47	44	56	54	49	45
45	55	53	48	45	56	54	49	46	58	56	51	47
50	57	54	50	47	58	55	51	48	60	57	53	49
55	59	56	52	49	60	57	53	50	62	59	54	51
60	61	58	54	51	62	59	54	51	64	61	56	53
65	49	48	46	-	50	49	47	42	51	50	48	43
70	50	49	47	-	51	50	48	43	52	51	49	44
75	51	50	48	-	52	51	49	44	53	52	50	45
80	52	51	49	-	53	52	50	45	54	53	51	46
85	53	52	50	-	54	53	51	46	56	55	52	47
90	54	53	52	-	56	55	53	48	58	57	54	49
95	56	55	54	-	58	57	55	50	60	59	56	51
100	58	57	56	-	60	59	57	52	62	61	58	53
105	60	59	58	-	62	61	59	54	64	63	60	55
110	62	61	60	-	64	63	61	56	66	65	62	57
120	64	63	62	-	66	65	63	58	68	67	64	59

Vibration velocity limits for single deep groove ball bearing

d	V			V1			V2			V3
mm	low	medium	high	low	medium	high	low	medium	high	low	medium	high
mm	band	band	band	band	band	band	band	band	band	band	band	band
3	80	44	44	60	35	32	48	26	22	31	16	15
4	80	44	44	60	35	32	48	26	22	31	16	15
5	110	72	60	74	48	40	58	36	30	35	21	18
6	110	72	60	74	48	40	58	36	30	35	21	18
7	130	96	80	92	66	54	72	48	40	44	28	24
8	130	96	80	92	66	54	72	48	40	44	28	24
9	130	96	80	92	66	54	72	48	40	44	28	24
10	160	120	100	120	80	70	90	60	50	55	35	30
12	160	120	100	120	80	70	90	60	50	55	35	30
15	210	150	120	150	100	85	110	78	60	65	46	35
17	210	150	120	150	100	85	110	78	60	65	46	35
20	260	190	150	180	125	100	130	100	75	80	60	45
22	260	190	150	180	125	100	130	100	75	80	60	45
25	260	190	150	180	125	100	130	100	75	80	60	45
28	260	190	150	180	125	100	130	100	75	80	60	45
30	300	240	190	200	150	130	150	120	100	90	75	60
32	300	240	190	200	150	130	150	120	100	90	75	60
35	300	240	190	200	150	130	150	120	100	90	75	60
40	360	300	260	240	180	160	180	150	130	110	90	80
45	360	300	260	240	180	160	180	150	130	110	90	80
50	420	320	320	280	200	200	210	160	160	125	100	100
55	420	360	360	280	220	200	210	180	180	125	110	110
60	480	360	440	320	220	240	240	180	200	145	110	130
65	300	260	420	180	160	240	130	100	150	105	80	105
70	360	310	460	200	180	280	150	120	200	110	90	135
75	360	310	460	200	180	280	150	120	200	110	90	135
80	420	360	540	240	210	320	180	120	240	130	110	160
85	420	360	540	240	210	320	180	150	240	130	110	160
90	480	420	600	290	250	370	210	180	270	145	125	180
95	480	420	600	290	250	370	210	180	270	145	125	180
100	560	490	670	340	300	420	250	215	310	170	145	200
105	560	490	670	340	300	420	250	215	310	170	145	200
110	640	570	750	400	350	480	290	260	350	190	175	225
120	640	570	750	400	350	480	290	260	350	190	175	225

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