In the lubrication and maintenance of double row tapered roller bearings, special attention should be paid to lubricant selection, lubrication cycle management, grease injection control, operating environment monitoring, and installation specifications. Specific precautions are as follows:
1. Lubricant selection: Matching working conditions is the core
Matching speed and lubrication method
Determine lubrication based on the speed coefficient
value (bearing inner diameter
d ×
speed
n
) Method:
dn<; 300000
: Suitable for grease lubrication, low cost and easy maintenance.
dn> 300000
: Oil lubrication (such as circulating oil or spray lubrication) is required to ensure heat dissipation and lubrication during high-speed operation.
Heavy duty condition: Choose lubricating grease containing
MoS
or extreme pressure additive (EP) (such as ISO L-XBCHB2 grade), with a base oil viscosity of not less than 100
mm
2
/s
to resist high-pressure wear.
.Environmental adaptability
High temperature environment: Choose high-temperature resistant lubricating grease (such as poly (alpha olefin) synthetic oil) to avoid lubricant carbonization.
.Dust environment: In cement, mining and other scenarios, it is preferred to use bearing units with triple lip seals to prevent particle intrusion.
.2. Lubrication cycle management: dynamic adjustment is key
grease lubrication replenishment cycle
Formula calculation:
T=
60n
d
10
6
gge is the hour,
n
is the rotational speed
r/min
,
d
is the bearing inner diameter
mm
). High temperature shortening: When the ambient temperature exceeds 40 ℃, the lubrication interval needs to be shortened by 30% -50%.
Automatic lubrication system: It is recommended to inject 0.5-2
cm
3
every 4-8 hours to avoid overfilling.
.Oil lubrication monitoring
Regular sampling: detect changes in oil viscosity (not exceeding ± 15% of initial value), moisture content (<0.1%), and particle contamination (below ISO 4406 standard 18/16/13 level).
.Online monitoring: using oil monitoring sensors to real-time monitor lubrication status and prevent lubrication failure.
.III. Control of grease injection amount: precise filling to prevent overheating
Filling amount standard
When lubricating with grease, the filling amount should be 1/3-1/2 of the internal space of the bearing.
. Overfilling can cause heating during mixing, leading to high temperatures.The automatic lubrication system needs to set a single grease injection limit to avoid local overheating.
Pollution prevention and control
Clean the oil nozzle before grease injection to prevent impurities from entering.
.When regularly replacing lubricating grease, it is necessary to thoroughly clean the old grease to avoid mixing old and new grease and causing performance degradation.
.4. Operating environment monitoring: Temperature and vibration are signals
Temperature monitoring
The normal operating temperature should be below 90 ℃, and the temperature rise should not exceed the ambient temperature+40 ℃.
. Using an infrared thermal imager to detect abnormal hotspots, a temperature gradient greater than 15 ℃ may indicate poor lubrication or alignment issues.Vibration analysis
Install vibration sensors in the vertical, horizontal, and axial directions of the bearing seat, with a sampling frequency of at least 10 times the fault characteristic frequency.
. Pay attention to the acceleration envelope values in the high-frequency range (5-10kHz), and the appearance of characteristic frequencies (such as BPFO, BPFI) and their harmonics indicates early damage.Fifth, Installation and Adjustment: Standardized Operation to Ensure Accuracy
Preparation before Installation
Bearings should be stored in their original packaging and opened one hour before installation.
.Clean the surface with gasoline, with a journal cylindricity error of ≤ 0.005mm and a surface roughness
Ra ≤ 0.8 μ m
.
Heating installation specifications
The heating temperature of the oil bath should be controlled at 80-100 ℃ (not exceeding 120 ℃), and the heating time should be calculated based on the bearing mass of 1.5 minutes per kilogram.
.Avoid directly tapping the bearings and use specialized tools (such as presses or induction heaters) to evenly apply force.
. Clearance AdjustmentDouble row tapered roller bearings have already been adjusted for clearance when they leave the factory, so there is no need to adjust them again during installation.
. Regularly measure the internal clearance during operation to ensure it is within the range of 0.05-0.10mm, in order to prevent excessive pre tightening or a decrease in system rigidity.