Crane bearing applications

Crane is in a certain range of vertical lifting and carrying heavy loads of multi-level action lifting machinery. Also known as crane. Belongs to the material handling machinery, but also for marine crane bearing, working characteristics of the crane is to do a batch Appropriate institutional movement, that in a work cycle Reclaimer, transport, unloading and other movements are alternately work Development and use of cranes on the market more widely. Crane hoisting mechanism includes running mechanism, luffing mechanism, slewing mechanism and metal structure. Hoisting mechanism is the basic working mechanism of the crane, mostly by hanging systems and winches composition, but also lift weights by the hydraulic system. Operational mechanism for horizontal transport of heavy or longitudinal adjustment of the position of the crane work, usually consists of motor, reducer, brake and wheel components. Luffing mechanism is equipped with only the jib crane, when the jib looked amplitude decreases, the amplitude increases when bent, sub balanced and unbalanced luffing luffing two. Boom slewing mechanism for causing rotation is determined by the drive means and the rotary bearing device component. Metal structure is the skeleton of a crane, the main carrier such as bridge, jib and mast can be a box-shaped structure or truss structure,But also for the web structure, and some can be used as a steel support beam.

High performance development of precision spindle bearings

Mr. Ye Jun said that, as a key basic parts, machine tool precision spindle bearings are the foundation to guarantee the machining accuracy index of machine tool. With the development of modern machine tools to the development of high precision, high speed, high reliability direction, put forward higher request to the spindle bearings.

  As in the traditional mechanical or general machinery, mainly in the hundreds to thousands of speed r / min/ agricultural bearings , while the modern high-speed processing machine, spindle speed required to reach tens of thousands to ten revolutions per minute. In the bearing industry, said the speed performance with dmN value, it is a product of the diameter and the speed of the machine tool spindle, the index is generally less than 2 million, the highest of 4 million, require very high.

  Therefore, bearing on the design requirements, with angular contact ball bearing as an example,marine crane bearing from material selection, structure design, guide way design, lubrication, groove curvature coefficient selection and other aspects needed for spindle requirements analysis, research.

TAC series of precision spindle bearing material

TAC series bearing（precision spindle bearings） of this brand are made of EP steel, the outstanding characteristic of having long life. EP steel NSK development with the characteristics of high purity, long life, high reliability, the rolling contact fatigue life is 3 times the average of SUJ2 bearing steel.

  LYHY agricultural bearings have been done in this area a lot of effort.TAC series of bearings adopt high dustproof light contact sealing ring, improve the reliability of. TAC series of marine crane bearing with light contact their independent development of the sealing ring is excellent, high speed, small temperature rise, high reliability.

TAC series of precision spindle bearing specialty

1.high performance design.

High Rigidity, ball number 600, contact angle, high stiffness.
Long Life, with EP steel long life, high reliability, service life is 3 times that of ordinary bearing( precision spindle bearings ) steel SUJ2.

2.
Contact sealed bearing series, high reliability, high dust
Sealed bearing dustproof performance is good, not easy leakage of lubricating grease. And the use of light contact seal ring,low bearing torque and fever.

3.installation convenience( marine crane bearing )

Open Bearing,provide has been filling grease products, shorten the installation time.

Sealed Bearing, has been filled with grease, and the back and front of the sealing rings of different colors, easy to identify the direction .

  Ball screw support contact ball bearing type series for thrust angle, sealed bearing series.

TAC series of precision spindle bearing

TAC series of bearings is  the ball screw support angular contact thrust ball bearing（ angular contact ball bearing ） under a brand of LYHY marine crane bearing peer , TAC series of bearings （agricultural bearings） include open bearing series, sealed bearing series.

TAC series  ball screw special bearing with high rigidity, high performance
and model complete, a wide range of uses,increase the sealing type series.

The spindle bearing parameter results

• Operation performance is better than that of ceramic ball bearing has the advantages of full steel bearing, the positioning preload more fully embodied, the speed limit of all steel bearings and ceramic ball bearing 4; n value, positioning preload were 1 X10 and 6.4 XIO 'bucket', fixed pressure preload were 2.4 XIO 'XIO', and 3.4 fixed pressure preload, ceramic ball bearing stiffness is greater than all steel bearings, and the positioning of preload on the contrary.

• In general, the angular contact ball bearings inner ring of the highest temperature, lowest temperature, the outer ring, but the constant preload - Factory rotate speed reaches to a certain value, the temperature may be higher than the inner ring outer ring.

• Measurement of  precision spindle bearings translational inherent frequency and the radial stiffness value and calculated value is consistent, ignore W1) d influence the measurement value is less than the calculated value, indicates that the theoretical analysis is correct. 

Experimental verification of spindle bearing

Through the theoretical analysis of spindle bearing , the results show that,

1) friction heat and pre tightening mode influence the speed and the dynamic performance of the bearing is very significant, bearing the quasi dynamic analysis to consider the friction heat and pretension.

  Methods influence the accuracy of computation is improved obviously, the results accord with the actual, friction heat and inertia effect of high speed increases the speed reduction bearing.
  And the dynamic performance of fixed pressure preload, the influence is less than positioning pretension, speed performance is better than the positioning pretension, preload for high speed.

2) using single flange bearing outer ring structure of low temperature than a double wall temperature, effect of ball number on the bearing temperature is small, the ball diameter and the initial contact angle increases raising the temperature, compared the positioning preload, fixed pressure preload more obvious; two pre tightening mode, ball diameter increases and the increase of the number of the linear ball bearing stiffness,effect of ball number increases, more than the ball diameter, the radial stiffness decreased the initial contact angle increases, the axial and angular stiffness increases, but the fixed pressure
preload, the axial and angular diameter increased stiffness decreases with increasing the initial contact angle can improve the axial and angular stiffness.

Study on the thermal characteristics of spindle bearings

The friction heat of spindle bearings significantly influence the speed and the dynamic performance of the precision spindle bearings 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 spherical roller bearing 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, agricultural bearings design and application parameters on the speed and dynamics, and validated by experiments.

spindle bearing,gricultural bearings

spindle bearing dynamics performance study  including ,
1) dynamic analysis of pseudo bearing, the establishment of improved quasi dynamics analysis method, considering the effect of friction heat and pre tightening mode, calculation of bearing load, motion, displacement, friction torque and friction heat equation.
2) calculation of bearing temperature distribution, using heat transfer theory, the establishment of the spindle unit of heat transfer model, derives the heat transfer resistance and heat transfer equation.
3) agricultural bearings operation performance calculation, the effects of example calculation and thermal characteristics, analysis of bearing design parameters and Preload Method on operation performance.

The third result of theoretical analysis of spindle bearings

The preload increases the temperature of the bearing and the stiffness will increase slightly, the fixed pressure preload, preload should increase with the rotational speed, the  marine crane bearing load and torque increases, positioning preload, the ambient temperature is high, the temperature rise of Vietnam, fixed pressure preload on the contrary.

  Oil mist lubrication, lubricating oil supply dose effect and viscosity and gas pressure bearing temperature, lubricating properties of synthetic lubricating oil is better than mineral oil, mineral oil contains a small amount of synthetic oil lubrication performance is best, can improve the speed performance of the precision spindle bearings the correct application of parameter selection.

Brief introduction of agricultural bearings

Agricultural bearings are special sealed ball bearings which are widely used in the foreign agricultural machinery.

  It is based on the disc plough, disc harrow and other agricultural tillage machinery, farming in the transfer load slurry easy to enter the working shaft bearing inner (Plow harrow shaft or axle) equidistantly installed multi bearing characteristics, specially designed a good sealing performance, good performance in bearing, big self aligning bearing capacity , easy to install and disassemble.

  The structure of agricultural bearings is very special, the inner hole is provided with cylindrical, four square, six square; outside diameter of cylindrical, spherical, cylindrical spherical mixed form. Stamping bearing seat some bearing is also provided with a square hole or a circular hole, the bearing can simplify the host structure, installation, disassembly and easy bearing.

Wear failure of marine crane bearing

Wear failure is one of the common failure mode of marine crane bearing , according to wear form is usually divided into the abrasive wear and adhesive wear the most common.
First of all, reasonable structure design of both have advanced, there will be a longer marine crane bearing  life. Manufacture of bearings are generally after forging, heat treatment, machining, grinding and assembling multi-channel processes. Rationality, advanced processing technology, the stability will also affect the service life of bearing. The effect of heat treatment and grinding process quality of finished double direction thrust ball bearing, often has a more direct relationship with the bearing failure. Bearing in recent years research on bearing surface modification layer of work shows that, the relationship between grinding and surface quality of bearing close.
The metallurgical quality of bearing materials is the main factor affecting the early failure of rolling bearings once. With the metallurgical technology (such as vacuum degassing of steel bearing) progress, improved quality of raw materials. Raw materials quality factors has been a marked decline in the proportion of Flange Slewing Bearing failure analysis, bearing, but it is still one of the main factors of bearing failure.