AKA SKATE BEARINGS CO.,LIMITED

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Skateboard Bearings

Longboard Bearings

Inline Skate Bearings

Kick Scooter Bearings

Roller Skate Bearings

Oil&Cleaner

Spacers

Tools

Retainer

Shields

Tel: +86-510-83231690
Fax: +86-510-83231699
E-mail: info@skate-bearings.com
Add: No.2,Jinshanbei Industry Zone,Wuxi City,214000,JiangSu,China

Technology

Structure of bearing

Single-row deep groove ball bearings are the most common type of rolling bearing, having a wide range of suitable applications. The raceway grooves on both inner and outer rings have circular arcs of slightly larger radius than that of the balls. In addition to radial loads, axial loads can be applied in either direction. Because of their low torque, they offer high speed operation with low power loss.

COMPONENT INDENTIFICATION

BEARING TYPES


Standard Open	Standard Shielded	Flanged Open	Flanged Shielded

Bearing Material

RINGS & BALLS vacuum degassed, high carbon chromium bearing steel GCr15 is the standard material for precision bearing rings and balls. The material has uniform specification as AISL 52100(America)DIN100 Cr6(German),JISSUJ2(Japan)

Steel No.	Chemical composition %
Steel No.	C	Si	Min	P	S	Cr	Mo	Cu	Ni
GCr 15	0.95-1.05	0.15-0.35	0.25-0.45	s0.025	s0.025	1.40-1.65	-	s0.25	s0.30

STAINLESS STEEL

Specification	Trademark	Chemical composition (%)
Specification	Trademark	C	Si	Mn	P	S	Cr	Mo
GB 3086	9Cr18	0.90-1.00	Below 0.80	Below 0.80	Below 0.35	Below 0.30	17.00-19.00
JIS G 4303	SUW440C	0.95-1.20	Below 1.00	Below 1.00	Below 0.40	Below 0.30	16.00-18.00	Below 0.75

RETAINERS-LB standard bearing retainers are made from cold rolled carbon steel however, in cases of corrosive environment, misalignment,or high speed operation, stainless steel, or phenolic resins will be used upon request.

1．CROWN RETAINER： The standard metal crown retainer is very light weight, with specially coined ball pockets to reduce torque and provide smooth running characteristics. Material used is 400 series stainless steel.
2．RIBBON RETAINER： The closed pocket design of the ribbon retainer is the most common type. The material used is 300 series stainless steel. For low torque applications, a loose clinched ribbon retainer may be available.
3．PHENOLICRETAINER： Plastic crown retainers have the highest speed ratings of any standard retainer type, but have limited availability.

Accuracy

There are stipulations to the roller bearing major size allowable tolerance, admittance value, rotating precision in the National Standard of GB3.7.1. the following is a comparison table between these admissions and ISO, JIS Standards:

Standard allowable tolerance grades
GB\T307.1	PO	P6	P5	P4	P2
ISO 492	Normal Class	Class6	Class5	Class4	Class2
JIS B 1514	JIS 0 Grade	JIS 6 Grade	JIS 5 Grade	JIS 4 Grade	JIS 2 Grade
AFBMA STD.20	ABEC 1	ABEC 3	ABEC 5	ABEC7	ABEC9

Lubrication

LUBRICATION

SRS bearings, single or double shielded (Z, ZZ) and single or double sealed (RS, 2RS). Before the formal shipment, we fill into the qualified oil or grease strictly. If you have any special requests about the lubrication, please feel free to show us and we can fill the corresponding oil or grease with the accurate rate as per your special requests. Below the following is our normal grease.

Manufacturer	Brand name	Basic type grease	Operation temp.c	Use
Exxon	Beacon 325	synthetic grease	-55~120	General purpose grease
Exxon	Andok B(Mil-G-18709A)	Channeling petroleum grease	-30~95	Excellent high speed,low torque,light mass
Exxon	Andok C	Channeling petroleum grease	-30~120	Smooth running,long life
G.E.Versilube G300		Silicone gorase	-75~205	Lighe loads and fine moderate speed
Mobil28	(Mil-G-81332)	Synthetic hydrocarbon	-55~180	Wide temperature range,good low temperature torque
Chevron		Mineral grease	-30~180	High temperature range with good water resistance
Shell	Alvania2	Mineral grease	-35~120	Long life and wide application
DuPont	Krytox 240AC(mil-G-27617)	Fluorinated grease	-35~290	High temperature stablility with good lubricity properties
Shell	Dolium R	Petroleum grease	-40~150	Good corrosion resistance and water resistance
KYODO	SRL	Synthetic grease	-40~150	Low noise,low torque and special case
NIG-ACE	W	Synthetic grease	-18~150	Low noise,low torque and special case
Mobil	HP	Lithium complex	-30~110	Vibration,moderate speeds and good corrosion resistance
Tianjin Hangu	Motor No.2	Mineral grease	-30~110	wide application,general purpose

Vibration and noise

The vibration and noise of bearings are classified as four classed as Z1,Z2,Z3 and Z4.It is measured by the instrument of S0910-1,For special requirement,it is measured by BVT-1 and classified as V1, V2, V3 and V4.The data are shown as below. Customer need mark their requirement of vibration and noise class on the order.

Tolerance data for vibration of single bearing

Tolerance in um/s

d mm	V			V1			V2			V3			V4
d mm	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand
3,4	80	44	44	60	35	32	48	26	22	31	16	15	28	10	10
5,6	110	72	60	74	48	40	58	36	30	35	21	18	32	11	11
7,8,9	130	96	80	92	66	54	72	48	40	44	28	24	38	12	12
10,12	160	120	100	120	80	70	90	60	50	55	35	30	45	14	15
15	210	150	120	150	100	85	110	78	60	65	46	35	52	18	18
17	210	150	120	150	100	85	110	78	60	65	46	35	52	25	25
20	260	190	150	180	125	100	130	100	75	80	60	45	60	25	25
22,25	260	190	150	180	125	100	130	100	75	80	60	45	60	30	32
28	260	190	150	180	125	100	130	100	75	80	60	45	60	35	40
30,32	300	240	190	200	150	130	150	120	100	90	75	60	70	35	40
35	300	240	190	200	150	130	150	120	100	90	75	60	70	42	45
40	360	300	260	240	180	160	180	150	130	110	90	80	82	50	50
45	360	300	260	240	180	160	180	150	130	110	90	80	82	60	60
50	420	320	320	280	200	200	210	160	160	125	100	100	95	70	70

Maximum vibration acceleration of single bearing

Tolerance in dB

d mm	Diameter Series(0)				Diameter Series(2)					Diameter Series(3)
d mm	Z	Z1	Z2	Z3	Z	Z1	Z2	Z3	Z4	Z	Z1	Z2	Z3	Z4
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	30	37	44	40	37	32
12	44	43	39	34	45	43	39	35	30	47	45	40	37	32
15	45	44	40	35	46	44	41	36	31	48	46	42	38	33
17	46	44	40	35	47	45	41	36	31	49	47	42	38	33
20	47	45	41	36	48	46	42	38	33	50	48	43	39	34
22	47	45	41	36	48	46	42	38	33	50	48	43	39	34
25	48	46	42	38	49	47	43	40	36	51	49	44	41	37
28	49	47	43	39	50	48	44	41	37	52	50	45	42	38
30	49	47	43	39	50	48	44	41	37	52	50	45	42	38
32	50	48	44	40	51	49	45	42	38	53	51	46	43	39
35	51	49	45	41	52	50	46	43	39	54	52	47	44	40
40	53	51	46	42	54	52	47	44	40	56	54	49	45	41
45	55	53	48	45	56	54	49	46	43	58	56	51	47	44
50	57	54	50	47	58	55	51	48	45	60	57	53	49	46
55	59	56	52	49	60	57	53	50	47	62	59	54	51	48
60	61	58	54	51	62	59	54	51	48	64	61	56	53	50

Internal clearance

Clearance is gap amid bearing inner ring, outer ring, ball package. Bearing has radial clearance and axial clearance.

Deep-groove ball bearing radial clearance

Nominal bearing inner diameter d（mm）		Clearance
Nominal bearing inner diameter d（mm）		C2		CN		C3		C4		C5
Exceed	Below	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.
10 (Be limited to)	-	0	7	2	13	8	23	14	29	20	37
10	18	0	9	3	18	11	25	18	33	25	45
18	24	0	10	20	5	13	25	20	36	25	48
24	30	1	11	5	20	13	28	23	41	30	53
30	40	1	11	6	20	15	33	28	46	40	64
40	50	1	11	6	23	18	36	30	51	45	73
50	65	1	15	8	28	23	43	38	61	55	60
65	80	1	15	10	30	25	51	46	71	65	105
80	100	1	18	12	36	30	58	53	84	75	120

Miniature Bearing's Internal Radial Clearance

Clearance mark

MC1

MC2

MC3

MC4

MC5

MC6

Clearance

max

min

max

min

max

min

max

min

max

min

max

min

Points of attention for using

Roller bearing is a precise part. Therefore it should be used carefully. No matter how high performance the bearing is, it can not be obtained by improper use. The followings are the points for attention of use to the bearings.
(1) Keep clean the bearing and its surrounding areas
It is harmful to the bearing even by tiny dust which can not be seen by human eyes. Therefore it should always keep clean the surrounding environments in order to prevent the bearing from dust corrosion.
(2) Cautious use of the bearing
Scar or indentation can easily be produced out of strong impact to the bearing in use and become the cause of accidents. It will even be cracked or broken in severe occasions.
Therefore special caution should be given to its use.
(3) Use the appropriate operating tool
It is forbidden to use the current tool in operation. Proper and appropriate tool should be adopted then.
(4) Be careful to the rust corrosion of the bearings
The sweat in the hands will cause rust in operating the bearings. Therefore your hands should be cleanly washed and dried before operation. You'd better wear gloves in doing the work.

Installation

The bearing installation has close relationships with the accuracy, life and performance. 　Therefore the design and assembly departments should fully research into the bearing installation.
It is better to implement installation according to the operation standard. The items of the operation standard are usually as follows:
(1) Clean bearing and its related parts
(2) Check the size and finishing conditions of the related parts
(3) Installation
(4) Examine bearings after installation
(5) Feed the lubricant
The bearing packing should be opened shortly before installation. There is no need for cleaning to ordinary lubricating grease lubrication, direct-filling of lubricating grease or lubricating oil. Whereas it should use the clean oil to rinse the instrument purpose bearing or high speed purpose bearing etc. and get rid of the anti-rusting agent on the bearing. The bearing easily gets rusty without rust inhibitor. Therefore special care should be taken to such kind of the bearing.
What is more, the bearing which has been sealed with lubricating grease can be put into direct use with no cleaning at all.
The installation methods of the bearing vary according to the difference in the bearing structure, matching, condition. As it is mostly of axle rotation, the inner ring needs interference fit. The cylindrical bore bearing is commonly pressed in by pressing machine or most probably, it adopts the heat installation method. The taper hole can be directly
installed in the taper axle or by sleeving.

Inspection and Test

In the whole course from purchasing of raw materials to every process of production, “SRS”Brand bearings are all strictly and carefully inspected to guarantee quality.Besides the basic and normally used testing instruments,the company also adopts the following testing and inspecting instruments to control the production processes and finished products.

No. Model No.of instrument
Name of instrument Test item
(1): HV-4B Pc high-speed automatic carbon and sulfur analyser Chemical composition of raw material
(2): HC-II High-speed digital display automatic analyzer
(3): 4X1 Metallurgical microscope Analysis of material and metallurgical structure
(4): Y9025 Roundness measuring equipment Roundness of groove and outer diameter
(5): R902 Groove curvature inspecting instrument Groove curvature and groove shape
(6): SRM-1 Surface roughness inspecting instrument Roughness of groove and surface
(7): S0910 Bearing vibration inspecting instrument (Accelerationg)vibration and abnormal sound
(8): BVY-1 Bearing vibration inspecting instrument (speed) vibration and abnormal sound