gear boxes in the equipment are rolling bearings, the friction between
the bearing rolling body and the inner and outer ring is called rolling
friction.The fit between bearing and shaft or bearing and end cover is generally interference fit or transition fit.Therefore,
the mutual extrusion pressure between the bearing and the shaft, or the
bearing and the end cover will be relatively large, resulting in static
friction, so that the bearing and the end cover or the bearing and the
shaft are in a state of mutual static, at this time, the transfer of
mechanical energy is to rely on the rotation between the inner and outer
ring and the rolling animal.And
if they fit for clearance fit between, can produce a torque to break
the relatively static state, the bearing and shaft, bearing and end
cover between relative slip occurs, this is called bearing run laps,
relative sliding bearing inner ring happens to run in circles, and
relative sliding bearing outer ring and bearing housing is to explore
the outer ring.
1. Representation of outer ring fault of gearbox bearing
after the removal of the gear box, there are obvious gliding traces on
the surface of the outer ring and the inner ring of the bearing seat,
and even more, the surface of the shaft or hole will grind out grooves.
(2) the measured hole ratio bearing outer diameter is greater than 0. 015mm.
Generally speaking, the temperature of the bearing part will be higher,
and the vibration frequency and amplitude will be larger.
2. Causes of failure of outer ring of gearbox bearing
(1) Fit tolerance.
matching degree between bearing and shaft, bearing and end cover is
very important. The matching tolerance between them has very strict
standards and provisions. Once greater than or less than this standard
provision, the bearing will have such and such problems, and the
phenomenon of bearing running outer ring is very common.In different cases, the requirements for tolerance are not the same.In
general, the fit between bearing and shaft, bearing and end cover is
interference fit in most cases, a few are excessive fit, these are in
line with the rules, once they appear clearance fit, there will be the
phenomenon of running outer or inner ring (mainly discuss running outer
(2) machining accuracy and installation accuracy
precision refers to the size, shape, position, roughness and other
technical parameters related to the precision of the shaft and the
bearing and the bearing base during the production and processing.Installation
accuracy refers to the technical standard for the installation of the
shaft and the bearing and between the bearing base and the hole.These all have their standard parameter values.Once
the tolerance is not accurate, the bearing running will cause wear and
even damage to the parts, which has a great negative impact.
(3) Material of shaft and bearing.
Material is also an important factor to consider.The
types of bearings are different, and the corresponding bearing
materials are different. The strength of bearings and shafts should be
large, with high wear resistance and should be reduced as far as
friction coefficient of bearing alloy can better prevent the bearing
from running out of the outer ring, and improve the service efficiency
and service time of the bearing.
3, the influence of gearbox bearing outer ring failure
phenomenon of outer ring running in bearings will increase the friction
between shaft and bearing, which makes the wear of parts serious and
the accuracy decreased.Secondly,
due to the generation of friction force, the mechanical energy will be
transformed into the thermal energy of friction loss, reducing the
transmission efficiency of the whole system.
4, bearing failure prevention measures
positioning accuracy directly affects the gear clearance, tooth life
and even the service life of the box body, which is particularly
important for its daily maintenance and fault prevention.When
inspecting the daily dimension of the gearbox bearing, we should first
pay attention to whether there is noise and abnormal fever during the
work of the gearbox. Once the abnormal phenomenon is confirmed, measures
should be taken immediately to avoid the expansion of the fault and
lead to irreparable damage.Secondly,
it is necessary to check whether the gearbox body and its lubrication
pipeline leak, whether the lubrication pipeline is loose or even broken.Again,
check whether the oil level and oil color of the lubrication station
are normal, and immediately find the oil leakage point when the oil
level drops.When the oil color is abnormal, the quality of the oil should be checked.Oil sampling should pay attention to the selection of poor operating conditions of the gear box.Then
through the inspection of oil results to analyze the working state of
the gearbox, to determine whether the performance of lubricating oil can
normally meet the needs of equipment operation, if necessary, the
bottom of the box (tank) impurities clean, if the bottom of the box is
equipped with magnetic components, also need to be cleaned.
(1) repair welding
welding is on the edge of the parts of the surface or coat a layer of
good abrasion resistance, corrosion resistance, heat resistance, and
other high performance metal layer, in order to protect the internal
structure of the original parts, but because of its function and role of
different parts, the need to cover the metal layer and the processing
craft are also different, thermal stress of repair welding defect is too
concentrated, easy to cause deformation of case etc parts.
(2) thermal spraying
spraying is mainly to atomize the metal layer that needs to be covered
by high temperature and then spray it to the parts that need to be
sprayed. Thermal spraying requires professional spraying tools and
certain skills. The main disadvantage of thermal spraying is that the
adhesion is not strong enough and it is easy to fall off.
(3) Brush plating
plating is the process of using electrolysis chemical method to cover
the required parts with metal. Its advantage is that it can be repaired
in line, but its disadvantage is also very obvious. The metal coating is
limited by the amount of wear.Generally can not exceed the thickness of 0. 02mm.
(4) Laser cladding
cladding technology refers to a method in which the coating and the
coating surface are melted together by laser technology with different
packing methods on the surface of the coated material, and then the
coating is covered on the parts.Its
advantage is not affected by the matrix metal, cooling speed is fast,
its disadvantage is easy to change, may produce cracks.
(5) Solei process repair technology
carbon nano polymer material is made of polymer, metal, nanometer
ceramic powder, carbon nanotubes, graphene, and other advanced materials
in curing agent, fixed-line promoter compound and into, under the
catalysis of various materials complement each other, can better than
raw materials", make it has strong adhesive force, good mechanical
properties and the advantages of strong corrosion resistance.Solei process repair technology is a new superior technology for the repair of the outer ring of the bearing.Solei
material long service life, does not have the stress, does not have the
high requirement to the thickness, the repair time is short, greatly
improves the product efficiency.When
the speed is below 1000 RPM, a variety of disassembly free repair
methods can be used to repair the problem, saving a lot of time and
labor.In general, the solei process repair technology is much better than the traditional technology, is a highly popular high-tech.
laps for the gearbox bearing failure problem, usually, inaccurate fit
tolerance, the machining accuracy and installation accuracy of gear box
bearing run laps and the influence of the impact of shaft and bearing
material to its, can be in based on some remedial measures or increase
the preventive measures, so that we can further to run laps bearing
fault phenomenon for prevention and control.