Using Tolerance Rings to Mount Ball Bearings
Design Engineers want to reduce cost and improve quality and performance. Choosing the most economical ball bearing for the job is one way to start. Surprisingly these high volume ball bearings are precision bearings. The low cost of these ball bearings is achieved by dedicated automated production machinery. The table below shows outside diameter tolerances and internal clearances of the most popular and the most economical ball bearings in the world. It also shows how easy it is to get into serious trouble if housing bore tolerances are not maintained!
Ball Bearing |
Tolerance Ring |
Nominal |
Nominal Bearing |
Recommenced |
Outside Dia. |
Outside |
Outside Diameter Tolerance |
Outside Diameter Tolerance inches |
Internal Clearance |
Internal Clearance |
607 |
AN19X6S |
0.2362 |
6 |
0.823/0.826 |
19 |
0.7480 |
.008 |
.00030 |
.002-.013 |
.00008-.0005 |
608 |
AN22X7S11 |
0.2750 |
7 |
0.944/0.942 |
22 |
0.8661 |
.009 |
.00035 |
.002-.013 |
.00008-.0005 |
6000 |
AN26X8S |
0.3150 |
8 |
1.098/1.101 |
26 |
1.0236 |
.009 |
.00035 |
.002-.013 |
.00008-.0005 |
6001 |
AN28X8S |
0.3150 |
8 |
1.177/1.181 |
28 |
1.1024 |
.009 |
.00035 |
.003-.018 |
.0001-.0007 |
6201 |
AN32X10S4 |
0.3937 |
10 |
1.334/1.338 |
32 |
1.2598 |
.011 |
.00045 |
.003-.018 |
.0001-.0007 |
6202 |
AN35X11S |
0.4331 |
11 |
1.452/1.456 |
35 |
1.3780 |
.011 |
.00045 |
.003-.018 |
.0001-.0007 |
6203 |
AN40X12S3 |
0.4724 |
12 |
1.649/1.653 |
40 |
1.5748 |
.011 |
.00045 |
.003-.018 |
.0001-.0007 |
6204 |
AN47X14S |
0.5512 |
14 |
1.924/1.928 |
47 |
1.8504 |
.011 |
.00045 |
.005-.020 |
.0002-.0008 |
|
||||||||||
R3A |
AN12.7X5S |
0.1960 |
0.555/0.558 |
.5000 |
.008 |
.00030 |
.002-.013 |
.00008- .0005 |
||
R4 |
AN16X5S |
0.6250 |
0.650/0.652 |
.6250 |
.008 |
.00030 |
.002-.013 |
.00008- .0005 |
* Note: When used in low strength materials such as aluminum, zinc, magnesium, plastics, etc., the housing bore should be reduced to provide more interference fit. For more information contact USA Tolerance Rings Engineering Department.
Bearing manufacturers offer a selection of 15 different housing Sizes for their ball bearings! The tolerances on the housings range from .0039 mm (.00015 inch) to .025mm (.001 inch). The housing diameter selections are an attempt to accommodate each and every application. The table above shows why bearing manufacturers require exacting housing tolerances. Too large a housing can cause sloppiness and bearing rotation in the housing. Too small a housing bores can cause precision bearings to preload and lock up. The bottom line is that on the average you will be required to machine (grind) a .012mm (.0005inch) housing bore. In many cases it just isn’t practical or economical to machine housings to bearing manufacturer recommendations.
Bearing Manufacturers wont tell you when a tolerance ring is the practical alternative! Tolerance rings allow the use of a less expensive precision ball bearing. They also provide the following benefits:
- In many applications using a tolerance ring will allow housing diameter variations of .08 mm (.003 inch) to .10 mm (.004 inch)
- Tolerance Rings can reduce bearing vibration and improve NVH characteristics
- Tolerance Rings allow for ease of assembly and removal
- Tolerance Rings can eliminate fretting corrosion
- Tolerance Rings can be used in as cast plastic and steel housings
- Tolerance Rings accommodate egg shaped out of round housings
- Tolerance Rings can accommodate ½ degree up to 3 degrees of misalignment
- Tolerance Rings provide a snug fit in the housing without the risk of bearing lockup
USA TOLERANCE RINGS
85 Route 31 North, Pennington, New Jersey 08534
phone:609-745-5000; fax:609-745-5012