Turned bronze bushing with grease track – Standard sizes
Turned bronze bushing. Unlike sintered bronze, this sliding bearing are more suitable for higher loads and lower rpm. These bearings must be lubricated. Dimensions from 14 mm are manufactured with an axially lubricating groove that works as a grease depot.
| Recommendations: | |
| Shaft tolerace | e7 |
| Bearing seat tolerance | H7 |
| Shaft surface hardness: | Min HB165 (N/mm²) |
| Shaft surface finish: | Rz 0,5 – 1,0 |
LOAD
For a bearing with inside diameter d and length L in mm andthe load F, expressed in Newton (N), the bearing pressureP is obtained according to;P= Fd x LN/mm2
Max static load: <90 N/mm²
Max dynamic load: <25 N/mm²
SLIDING VELOCITY
Sliding velocity under 1 m/min or intermittent operation.
At sliding velocity ≤ 0.017 m/s (1 m/min) or intermittent
operation, bearing pressure P can be set equal to half the
stress value of the bearing material.
Sliding velocity above 1 m/min or continuous operation.
At continuous operation and/or higher sliding velocity (>0,017
m/s) the PV value is used, i.e. the bearing pressure in N/mm2 multiplied
with the sliding velocity in m/s, for assessment of max bearing pressure.
A PV value of 1,75 can normally be allowed for the majority of bronze alloys.
Ex.: sliding velocity V = 0,10 m/s gives max bearing pressure
1,75/0,10 = 17,5 N/mm2.
Sliding bearings above 60 m/min
At sliding velocity > 1 m/s (60 m/min) with oil lubrication,
hydrodynamic operation (i.e. full film lubrication) may
be obtained under special circumstances.
BEARING GAP
At oil lubrication, 1,5–2,5 ‰ of the inner diameter is recommended.
Att grease lubrication, the gap should be 2x larger. At high temperatures, the gap
should be increased. At pendulous
motion, keep the gap as small as possible (0,5–1 ‰).
LUBRICATION
The lubrication grooves in the bearing are very important. Poor
lubrication is often due to faulty constructed lubrication grooves.
Generally a lubrication groove should never be placed in a zone
with load. There is one exception; at pendulous motion.
Solid lubricants which have the highest load capacity,
may be used when the sliding velocity is < 0,5 m/s.