Hydraulic excavators installations shaft and bearing design '

Kunshan Bearing: Equipment reliability of the hydraulic excavator machine performance impact and work equipment at work, the working conditions of low speed and heavy, which the shaft and bearings made very high performance requirements, and the excavator design, the weight of the working device can meet the design performance parameters in the premise should be as small as possible, so the rational design of shafts and bearings for excavator machine performance is critical. Here are discussed shafts, bearings, shaft and bearing tolerances design.
A,angular contact ball bearing design: working device bearing a wide range of materials can be divided according to their bronze bearings, steel bearings, composite bearings, etc.; their lubrication can be divided into dry friction bearing, oil bearing, incomplete film bearings, fluid film bearings, etc.: I plant is used for the lubrication of bearings incomplete film lubrication, has used copper, steel, copper and many other steel back self-lubricating bearings. Copper bearing good toughness, wear resistance in general, the shaft has a good protective effect, but poor resistance to deformation, deformation after prolonged use, causing the bearing diameter to expand, resulting in structural parts shaking; steel bearing high strength, wear good resistance to deformation ability, but the surface treatment process requires high; copper steel back self-lubricating bearings and copper bearing steel bearing both the advantages of both sump lubrication and self-lubricating combination, can effectively avoid bearing charred, but the process is complicated and costly.
Bearing design primary consideration is the bearing life, the life of the bearing outer diameter in addition to burning the amount of wear to decide. Mainly by the amount of wear of the friction conditions, but also by the friction load, speed, impurities, surface roughness, temperature, different operation modes, using a lubricant conditions, therefore, the amount of wear is only a theoretical estimate, bush life depends on a variety of complex conditions. Ruoyin oil poor penetration of impurities leaving the wear rapidly changing, it is difficult to predict wear. Under normal circumstances, the copper bearing (ZcuAll0Fe3Mn2) Wear approximated by the following equation:
W = K × P × V × T
W: amount of wear (mm)
K: friction coefficient [mm / (N/mm2 · m / min · hr)]
P: load capacity (N/mm2)
V: line speed (m / min)
T: Wear time (hr)
Where K = Ci × k, k is the ideal state of the friction coefficient, K = (1 ~ 5) × 10-8 [mm / (N/mm2 · m / min · hr)]
1, Ci = C0 × Cl × C2 × C3
2, the bearing pressure P
Bearing pressure is usually called the bearing under load, the bearing support of the maximum load divided by the pressure receiving area, the so-called pressure area, when the bearing is cylindrical, take the contact portion of the load bearing direction of the projection area.
3, the speed V
Bearing heat, mainly caused by the friction of the bearing, can be obtained based on experience, the surface temperature rise of the friction, the sliding bearing is far greater than the velocity V of the pressure P.
Thus, the bearing life mainly determined by the value P × V. Determines both the PV bearing heat. Running when the bearing, the bearing temperature by the heat generated by friction and heat dissipation-affected, usually stabilize at a certain temperature, if there are impurities in the ongoing operation invasion, will reduce the performance lubricants, and because of the influence of friction powder , material fatigue, deformation of the friction surface at this time is changed, the friction coefficient is increased, the bearing temperature rise, resulting in damage to the friction surface, leading to burning, based on this condition, the bearing operating temperature is lower, that is, using the low PV value, the bearing load is better, life expectancy, so the design as much as possible the use of lower PV value