Ferrofluidic Seals
(FerroSeals)

Robot Seal

Exclusion Seals

Ferrofluidic Dust Seals (Exclusion Seals)

Exclusion Seals are dust seals that have been proven with hundreds of millions of units used in hard disk drive motors. Basically, a magnetically permeable shaft is passed through a magnetic circuit unit consisting of a permanent magnet and two pole pieces as the north and south poles. The magnetic flux is concentrated in the radial gap between the shaft and pole pieces. Ferrofluid is injected into the gap to form a liquid O-ring seal. There are a wide variety of applications, including hard disk drive motors, industrial cleaning robots, and cleaning robots for vacuum environments.

Dimension Table

NO. A B C D E
Shaft Outer Diameter
(Recommended Tolerance h7)		 Mounting Part Inner Diameter
(Recommended Tolerance)		 Seal Inner Diameter Seal Outer Diameter Seal Thickness (Tolerance ±0.4)
NO.１ NO.２
１ φ10 φ20 +0.031
+0.010		 φ10.3 φ20 2.5 3
２ φ15 φ25 φ15.4 φ25 2.5 3
３ φ20 φ30 φ20.4 φ30 2.5 3
４ φ25 φ35 +0.035
+0.010		 φ25.4 φ35 2.5 3
５ φ30 φ40 φ30.4 φ40 3 4
６ φ35 φ45 φ35.4 φ45 3 4
７ φ40 φ50 φ40.4 φ50 3 4
８ φ45 φ55 +0.04
+0.01		 φ45.4 φ55 3 4
９ φ50 φ60 φ50.4 φ60 4 5
10 φ55 φ65 φ55.4 φ65 4 5
11 φ60 φ70 φ60.4 φ70 4 5
12 φ65 φ75 φ65.4 φ75 4 5
13 φ70 φ80 φ70.4 φ80 4 5
14 φ75 φ85 +0.045
+0.010		 φ75.4 φ85 4 5
15 φ80 φ90 φ80.4 φ90 4 5
16 φ85 φ100 φ85.4 φ100 4 5
17 φ90 φ105 φ90.4 φ105 4 5
18 φ95 φ115 φ95.4 φ115 4 5
19 φ100 φ120 φ100.4 φ120 6 ー
20 φ105 φ125 +0.05
+0.01		 φ105.4 φ125 6 ー
21 φ110 φ130 φ110.4 φ130 6 ー
22 φ115 φ135 φ115.4 φ135 6 ー
23 φ120 φ140 φ120.4 φ140 6 ー
24 φ125 φ145 φ125.4 φ145 6 ー
25 φ130 φ150 φ130.4 φ150 6 ー
26 φ135 φ155 φ135.4 φ155 6 ー
27 φ140 φ160 φ140.4 φ160 6 ー
28 φ145 φ165 φ145.4 φ165 6 ー
29 φ150 φ170 φ150.4 φ170 6 ー

* Please consult with us for special specifications such as high temperature (Max. 150℃) and high withstanding pressure (0.15kg/cm2).

■ Specifications (Reference)

Operating Temperature Range Radial Gap Allowable Shaft Speed Seal Withstanding Pressure Cleanliness
Room temperature to 70℃ 0.15〜0.25mm 100rpm〜10000rpm 1000Pa Zero particle of 0.3μm or larger

* No condensation* Shaft rotation