Page 52 - needle bearings

Sealing Devices
NTN

Table 9.4 Seals (NTN contact seals)
Seal type Contact seals (G type, GD type)

Seal using mainly direct contact

This seal type is a special-purposed seal for needle roller bearings which was designed for smaller section height so as to correspond
Features flexibly to the said bearings.
This is a synthetic rubber contact seal reinforced with steel plate, being then used in the operating temperature range of -25 to +120˚C
and, under continuous running condition, used at 100˚C and less. For application under special operating conditions of over 120˚C at
operating temperature, etc., feel free to contact NTN for any inquiry.

Application examples

Fig. 9.13 Bearing sealing by NTN seals (Example)

9.7 Shaft surface roughness
Sealing performance and seal life depend on the
surface roughness, accuracy and hardness of shaft
sliding surface with which the seal lip comes in contact.
Table 9.7 shows the surface roughness as a guideline.
For improving better the wear resistance of shaft surface
it is desirable to secure the shaft surface hardness at
least at HRC40 and over (at HRC55 and over if possible)
by heat treatment and hard chrome plating.

Table 9.7 Shaft surface hardness (Reference)
Peripheral speed m/s Surface roughness
overɹɹɹ incl. Ra
5 0.8a
5 10 0.4a
10 0.2a

A-48