Reasons for common problems of worm gear slew drives
1. The reducer heats up and leaks oil. In order to improve
efficiency, worm gear reducer generally use non-ferrous metals as
worm gear, worm is the use of harder steel. Because it is a sliding
friction drive, the operation will produce more heat, so that the
reducer between the parts and seals of the thermal expansion of the
difference, so that in the coordination surface to form a gap,
lubricant liquid due to the increase in temperature thinning, easy
to cause leakage.
There are four main reasons for this situation: 1) the collocation
of the material is unreasonable, 2) the poor quality of the surface
of the meshing friction surface, 3) the incorrect choice of
lubricating oil addition; 4) the assembly quality and the use of
the environment is poor.
2. Worm gear wear. Worm wheel generally uses tin bronze, paired
worm material with 45 steel hardened to HRC4555, or 40Cr hardened
HRC5055 after grinding through the worm grinder to roughness
Ra0.8μm. The gearbox is slow to wear during normal operation, and
some reducers can be used for more than 10 years. If the wear is
fast, we must consider whether the selection is correct, whether
there is overload operation, as well as the worm material, assembly
quality or operation environment and other reasons.
3. Small oblique gear wear. Generally occurs in the vertical
installation of the reducer, mainly related with the amount of
lubricant added and oil types. It is easy to cause insufficient
amount of lubricating oil when vertical installed. When operation
stopped, oil loss between the motor slew drive, the gears could not
get the proper lubrication protection. When the reducer starts, the
gears are mechanically worn or even damaged due to lack of
4. Worm bearings are damaged.
In the event of failure, even if the gearbox is well sealed, it is
often found that the gear oil in the reducer is emulsified, the
bearing rust, corrosion, damage. This is because after a period of
operation, the temperature of the gear oil increased and cooled
after the condensation of water mixed with water. Of course, it is
also closely related to bearing quality and assembly process.
Solution to common problems of slew drives
1. Guarantee the quality of the assembly. You can purchase or make
some special tools. When disassembling and installing the parts of
the reducer, try to avoid hitting with other tools such as hammers.
When replacing gears and worm gears, try to use the original parts
and replace them in pairs; when assembling the output shaft, pay
attention to Tolerance fit; use a release agent or red dan oil to
protect the hollow shaft to prevent wear and rust or to match the
area scale, which is difficult to disassemble during maintenance.
2. Selection of lubricants and additives. The worm gear slew drive
generally uses 220# gear oil. For heavy-duty trucks with heavy
load, frequent start and poor use environment, some lubricating oil
additives can be used to make the gear oil still adhere to the gear
surface when the reducer stops running, forming protection.
Membrane formed to prevent heavy load, low speed, high torque and
direct contact between metals at start-up. The additive contains a
seal regulator and a leak preventer to keep the seal soft and
elastic, effectively reducing oil leakage.
3. Selection of the mounting position of the slew drives. If
possible, do not vertical installed. When installed vertically, the
amount of lubricating oil added is much more than that of
horizontal installation, which may cause heat generation and oil
leakage of the reducer.
4. Establish a lubrication maintenance system. The reducer can be
maintained according to the “five-set” principle of lubrication
work. Every slew drive has a responsible person to check regularly
and find if the temperature rise is obvious. If the temperature
exceeds 40°C or the oil temperature exceeds 80°C, the quality of
the oil will drop. When more copper powder is found in the oil and
abnormal noise is generated, stop using it immediately, repair it
in time, troubleshoot it, and replace the oil. When refueling, pay
attention to the amount of oil to ensure that the gear unit is