Study on the thermal characteristics of rotary bearing

The friction heat of spindle bearings significantly influence the speed and the dynamic performance of the rotary bearing unit, is restricting the main factors to improve the machining efficiency and precision.
To build up the heat transfer equations, the friction heat and temperature distribution calculation of bearing, thermal characteristics research of bearing, and its impact on the speed and dynamics is an important topic with theoretical
and practical significance.
In this paper, based on the heat transfer, tribology of agricultural bearings and rotor dynamics as the theoretical basis,taking the GDZ48A type electric spindle as an example, establishes the spindle bearing considering the effect of friction heat and pre tightening mode quasi dynamics analysis model, analyzes the bearing friction torque, motor, load and stiffness, study the influence of thermal characteristic, tower crane bearing design and application parameters on the speed and dynamics, and validated by experiments.

Mobile crane bearing hoisting mechanism brake system

Brake system in the lifting mechanism is arranged on the brake cylinder, so as to turn in a hydraulic motor,agricultural bearings , brake lock lifting hydraulic motor. At the same time in the brake cylinder into the oil passage is provided with a one-way throttle valve, and its role is to enable the brake brake fast, slow release the brake.

  The former is to enable the motor to brake quickly, quickly stopped falling weight. The latter is when the load lifting process again in mid air,mobile crane bearing , avoid heavy weight of the hydraulic motor drag inversion and produces transient downhill phenomenon.

Hydraulic truck mobile crane bearing

Due to the arrangement of the balance valve( marine crane bearing ), so that the hydraulic motor can only have the pressure in the oil inlet of case rotation, so falling will not produce the phenomenon of nod.

  But the leakage of the hydraulic motor of the hydraulic cylinder is much larger than that when the load hanging in the air, although the balance valve is provided with a circuit,agricultural bearings  ,they may still produce the slipping phenomenon.

Crane bearing and the ship crane bearing technical characteristics comparison

Slewing bearing is bearing the heavy industry is extremely important, diameter ranging from 10cm to 10 m, almost all of the large equipment to do reciprocating circular motion.

• Wind turbine slewing bearing

  Technical features: the yaw bearing is installed on the connecting part of the tower and cabin,variable paddle bearing installed in the root and the hub of each blade connecting parts. Each wind generator with a set of yaw bearing and three sets of variable pitch bearings. Yaw, pitch bearingmaterials selected 42CrMo, heat treatment using whole quenching and tempering treatment, the raceway surface quenching. The stress situation of yaw, pitch bearing complex, but also bear theshock and vibration is relatively large, therefore, requirements of bearing can bear the impact, but also can bear larger ship loader bearing.

  Wind turbine host life requirement of 20 years, the cost of installation and bearing large, therefore asked the yaw, pitch bearing life to reach 20 years. Bearing ring matrix hardness is 240-280HB,able to withstand shock and plastic deformation does not occur at the same time, the racewaysurface quenching hardness reaches 55-62HRC, which can increase the contact fatigue life, so as to ensure the long life of use requirements of bearing.

• The ship crane slewing bearing

The crane load bearing requirements of large, flexible rotation, relatively high speed, rotation of 270 degrees, the action to be fast, so the selection of internal tooth, double row ball slewing bearings. Crane bearing and the ship crane bearing technical characteristics comparison

•  Offshore platform crane bearing

According to the requirement of the bearing capacity of different, offshore platform crane often use four point contact ball slewing and the three row roller slewing bearing inner tooth.

Slewing bearing used in the offshore platform crane requires special material, the mechanical properties of the material to be able to ensure the safety coefficient of limit load, forging samplingCharpy impact experiment can achieve the average value of 42 J@-20 degrees C or 27J @ -40 C.Bearing finished product to Norske Veritas certification CCS.

Way of bearing temperature during processing by lubricating spherical roller

There are pre-filled with grease greased sealed manner in sealed bearings, as well as inside the casing filled with the right amount of grease at regular intervals to supplement or replacement for grease filling mode. In addition, there are many excavator bearing  eed lubricating machinery, also uses the pipe connected to the lubrication at centralized way for fat. Grease filling can be done after the first time without grease supplement, and its structural sealing device is also relatively simple, so widely used. Lubricating oil is relatively simple. Regular lubrication can greatly improve the spherical roller bearing life Oh!
bearings when the temperature rises, first determine whether the error first move to do, if the temperature is indeed rising, Dangdang that do the following disposition:
(1) Check the cooling water pressure, flow and piping system can generally bearings. If water filter may be clogged down, can not timely disposal of hot disassembly spherical plain bearings ylindrical bore bearings can shut down the disposal, can work when the confirmation is done, then put into use.
(2) When the check governor oil pressure, oil pressure may result if the cooling water hydraulic valve closed.
(3) check whether no bearing spherical ball with the outside of the soundtrack, and can not detect bearing swing very much.
(4) to take oil samples to see whether the oil did not change color, bearing and conduct tests to see whether the variables. If confirmed deterioration, stop change when the new oil.
(5) Check the oil standard oil level can generally, if the non-general, check whether the tank drain valve closed. If the bearing is not closed, when up the oil, if oil leakage sealing pads, when stopping for disposal.
Bearing lubrication performance can be divided into the following areas:
1, the first portions of lubricating spherical roller bearings, reducing bearing friction and wear;
2, the rolling contact surfaces of the bearing oil film often form appropriate to extend the fatigue life of the bearing;
3, through the heat inside the bearing lubrication away due to friction or other causes;
4, by ship loader bearing lubrication to the role of rust and dust.

Development of wheel bearings

   Traditional automotive agricultural bearings is composed of two tapered roller bearings or ball bearing combination, bearing installation, oiled, sealed and adjust clearance are carried out in the car on the production line. This structure makes it difficult in a car assembly plant, high cost, poor reliability, and maintenance car maintenance, but also the need for bearing cleaning, oiling and adjustment.
    Developed on the basis of the hub bearing unit is the standard angular contact ball bearings and tapered roller bearings on, it will be two sets of bearings as a whole, with good assembly performance can be omitted clearance adjustment, light weight, compact structure, load capacity large, sealed linear plain bearings grease can be loaded in advance, hub seals and omitted from the outside wheel maintenance, etc., has been widely used in cars, and in the truck also has a tendency to gradually expand the application.
    Car wheel bearings are used in pairs over most single row tapered roller or ball bearings. With the development of technology, the car has been widely used car wheel units. Growing scope and use of the hub bearing unit, has now developed to the third generation:
The first generation is a double row angular contact bearing components.The
second generation of the outer raceway has a flange for fixing the crane bearing

, the bearing sleeve may simply be fixed with a nut on the axle. So that the vehicle maintenance becomes easy.The third generation wheel hub bearing units are used bearing unit and ABS anti-lock brake system fitted. Wheel hub unit is designed to have the inner flange and outer flange, the inner flange is bolted to the drive shaft, the entire bearing outer flange fit together.