Bearings play a key role in supporting and driving construction machinery. Here is a detailed description:

Applications in excavators

Working device: Bearings are required for the connecting parts of the boom, bucket rod and bucket of the excavator. For example, at the hinge point between the boom and the fuselage, large joint bearings are used, which can withstand huge bending moments and impact forces, while ensuring the flexible rotation of the boom. The excavation action of the bucket is realized through the hydraulic cylinder and the connecting rod mechanism, and the cooperation between the pin and the shaft sleeve is actually a special form of bearing. These bearings need to withstand the digging force and friction while adapting to various complex working postures and soil conditions. The extension and contraction of the bucket rod also depends on high-quality bearings. Generally, cylindrical roller bearings or spherical roller bearings are used to meet the load and rotation requirements of the bucket rod at different working angles.

Rotary mechanism: The slewing platform of the excavator is a key part of the 360-degree rotation of the fuselage, while the slewing bearing is the core component to support and realize the slewing movement. The slewing bearing is usually a large rolling bearing with inner and outer rings, rolling elements and cages, which can bear the weight of the fuselage and various forces and moments when rotating. The connection between the slewing motor and the slewing bearing is usually geared, and the gear shaft in it also needs to use high-performance bearings. These bearings need to ensure the accurate meshing and transmission efficiency of the gears, while also withstanding the impact load and vibration when rotating.

Walking system: The crawler running device of the excavator needs to use a variety of bearings. Rolling bearings, such as tapered roller bearings or double row cylindrical roller bearings, are installed on the shaft of the track wheel to bear the pull of the track and the weight of the fuselage, while ensuring the smooth rotation of the track. The bearings of the drive wheel and the guide wheel are also very critical. The drive wheel meshes with the track through gears to transmit power to the track, and its bearings need to bear large torque and impact loads. The guide wheel is used to guide the direction of movement of the track, and its bearings need to have good guiding performance and wear resistance.

Applications in loaders

Bucket and boom system: The bucket of the loader needs to be frequently lifted and turned when loading materials, and the bearings used in the connection between the bucket and the boom need to bear greater impact and friction. For example, the use of high-strength joint bearings or pin bearings can ensure the flexible movement of the bucket under various working conditions. The lifting and lowering of the boom is realized through the hydraulic cylinder and the connecting rod mechanism, in which the pin and bearing cooperate to play a key role. Generally, cylindrical roller bearings or spherical roller bearings are used to adapt to the bearing and rotation requirements of the boom at different working angles. The working device of the loader may also be equipped with automatic leveling function, which needs to be realized by some special hydraulic and mechanical structures, which also involve some precision bearings and sliding parts.

Transmission system: The gearbox of a loader is a key component that transmits the power of the engine to the wheels. The gear shafts and drive shafts in the gearbox need to use various types of bearings. For example, cylindrical roller bearings are used to support the rotation of the drive shaft, and tapered roller bearings are used to bear the axial and radial loads of the gears. The drive axle is an important part of the loader's walking system, and the differential and half shafts need to use high-quality bearings. Differential bearings need to ensure the normal operation and power distribution of the differential, while half-shaft bearings need to bear the driving and braking forces of the wheels.

Steering system: The steering system of the loader usually uses hydraulic power steering, and the components such as the steering cylinder and the steering knuckle need to use bearings. The bearings at the steering knuckle need to withstand the lateral force and bending moment of the vehicle during steering, while ensuring the flexibility and accuracy of the steering. Some large loaders may also be equipped with a fully hydraulic steering system, and the components such as the hydraulic pump, hydraulic motor and steering valve also need to use some special bearings and seals to ensure the normal operation of the hydraulic system.

Applications in cranes

Lifting mechanism: The hoisting mechanism of a crane is a key part for lifting and lowering heavy objects. The reel and wire rope pulley block need to use a large number of bearings. The bearings on the reel need to withstand huge tension and torque, and at the same time ensure the smooth rotation of the reel. Generally, large cylindrical roller bearings or tapered roller bearings are used, which have high load-bearing capacity and good stability. The pulley shafts in the wire rope pulley block also need to use bearings. These bearings need to withstand the friction of the wire rope and the tension of the heavy object while also ensuring the smooth rotation of the pulley. Usually deep groove ball bearings or spherical roller bearings are used, which have good wear resistance and impact resistance.

Rotary mechanism: The slewing platform of a crane needs to be able to rotate 360 degrees, and slewing bearing is a key component to achieve this function. Slewing bearing is usually a large rolling bearing with inner and outer rings, rolling elements and cages, which can withstand the weight of the crane body and various forces and moments when rotating. The connection between the slewing motor and the slewing bearing is usually geared, and the gear shaft in it also needs to use high-performance bearings. These bearings need to ensure accurate meshing and transmission efficiency of the gears, while also withstanding the impact loads and vibrations when rotating.

Telescopic boom and luffing mechanism: The telescopic arm of the crane is a key part to realize the change of working radius. The telescopic action of the telescopic arm is realized by hydraulic cylinder and chain or wire rope. The pulley, pin and guide device in it all need to use bearings. For example, the cooperation between the slider and the guide rail of the telescopic arm adopts special sliding bearings or rolling bearings to ensure the smooth telescopic and positioning accuracy of the telescopic arm. The luffing mechanism is used to adjust the elevation angle of the lifting arm. The hydraulic cylinder and connecting rod mechanism in it also need to use various types of bearings. The connection between the piston and the piston rod of the luffing cylinder needs to use well-sealed bearings to prevent the leakage of hydraulic oil and ensure the accuracy of the action.

Application in road roller

Vibration system: The vibration function of the road roller is the key to realize the compaction of the road surface. The connection between the eccentric shaft and the vibration wheel in the vibration system requires the use of high-quality bearings. These bearings need to rotate at high speed and withstand huge centrifugal force while also ensuring the stability and reliability of vibration. Generally, specially designed cylindrical roller bearings or spherical roller bearings are used, which have high bearing capacity and impact resistance. At the same time, in order to reduce the impact of vibration on the bearings, some shock absorption and buffering devices are also used. The transmission between the vibration motor and the eccentric shaft also requires the use of bearings. These bearings need to ensure the accurate transmission of power and adapt to the working conditions of high-speed rotation.

Walking system: The running device of the road roller usually uses tires or steel wheels. Rolling bearings, such as tapered roller bearings or double-row cylindrical roller bearings, need to be used on the tire shaft of the tire roller to bear the weight of the vehicle and various forces when driving. The steel wheel shaft of the steel wheel roller also needs to use bearings. These bearings need to withstand the reaction force and vibration of the road surface while also ensuring the smooth rotation of the steel wheel. Special sealed bearings are generally used to prevent dust and debris from entering the inside of the bearing.

Steering system: The steering system of a road roller requires the use of some special bearings and steering components. For example, the connection between the steering cylinder and the steering knuckle requires the use of joint bearings or pin bearings to ensure the flexibility and accuracy of the steering. Some large road rollers may also be equipped with a fully hydraulic steering system, in which components such as hydraulic pumps, hydraulic motors and steering valves also require the use of some special bearings and seals to ensure the normal operation of the hydraulic system.

Bearing selection and maintenance points

Selection principle: According to the working characteristics and load requirements of construction machinery, choose the appropriate type and specification of bearings. For example, for heavy loads and large impact loads, roller bearings should be selected; for high-speed rotating parts, ball bearings or high-precision roller bearings should be selected. Consider the working environment of construction machinery, such as temperature, humidity, dust and corrosive media, etc., choose bearings with corresponding protective properties. For example, use sealed bearings or bearings with dust covers to prevent dust and debris from entering the bearing interior; choose corrosion-resistant bearing materials to adapt to harsh working environments. Choose bearings of appropriate size and shape according to the installation space and structural requirements of construction machinery. For example, for areas with limited space, miniaturized or ultra-thin bearings should be selected; for areas that require greater axial force, bearings with greater axial bearing capacity should be selected.

Maintenance measures: Regularly check the operating status of bearings, including temperature, noise, vibration and lubrication conditions, etc. By monitoring these parameters, abnormal conditions of bearings can be detected in time, such as overheating, abnormal noise, excessive vibration or poor lubrication, etc., and take corresponding measures for repair or replacement. Keep bearings clean and lubricated. Regularly clean bearings, remove dirt and impurities on the surface, and add an appropriate amount of lubricating oil or grease. According to the working conditions and frequency of use of construction machinery, formulate a reasonable lubrication cycle and lubrication method to ensure that bearings are always in good lubrication condition. For damaged bearings, they should be replaced in a timely manner. When replacing bearings, they should be carried out in strict accordance with the operating procedures to ensure the installation quality and accuracy. At the same time, relevant components should be inspected and maintained to ensure the normal operation of the entire construction machinery. Strengthen the training of construction machinery operators to improve their awareness and skills in bearing maintenance. Operators should understand the basic working principle and maintenance points of bearings, be able to operate construction machinery correctly, and avoid damage to bearings due to improper operation.