Proper seal installation assures sealing performance. How a seal is fitted is very important.

The end of shaft must be chamfered, corners must be rounded free from burrs and sharp edges to protect seals from damage during assembly. The contact area for the sealing lip has a crucial effect on the sealing.

 

Material

Steel, casting iron, hard chrome coating, engineering plastic, etc.

 

Hardness

For slower circumferential speed (<5m/sec), it is possible to run with untampered shaft. If speed is higher, the surface hardness must be hardened to minimum Rockwell 45 HRC.

With soiled media, dirt from outside, or circumferential speed > 12m/sec, hardness needs 60HRC, hardening thickness >0.3 mm

 

Most often used method is plunge-cut grinding, this can ensure non machine lead on the shaft. Too large roughness value cause a premature wear and leakage. Too low roughness value, the lubricant cannot reach the sealing edge. This will result premature gardening and cause cracks at sealing lip.

 

Recommend roughness value

Ra = 0.2~0.8um      Rz = 1.0~5.0um      Rmax ≦ 6.3µm

At operating pressure >1 bar

Ra = 0.2~0.4um      Rz = 1.0~3.0um      Rmax = 6.3µm

 

Shaft Diameter

 

Shaft Diameter	Tolerance range(h9)	Shaft Diameter	d
1~6	-30~0	1~10	SD-1.5
7~10	-36~0	11~20	SD-2
11~18	-43~0	21~30	SD-2.5
19~30	-52~0	31~40	SD-3
31~60	-62~0	41~50	SD-3.5
51~80	-74~0	51~70	SD-4
81~120	-87~0	71~90	SD-4.5
121~180	-100~0	91~140	SD-5
181~250	-115~0	141~250	SD-7
251~315	-130~0	>250	SD-11
316~400	-140~0