Fault analysis of the vibration system of the hott

2022-09-28
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Vibration system fault analysis of vibratory roller

Guide: the vibration system is the main working system of the vibratory roller. Analyzing and eliminating the faults of the vibration system is of great significance to improve the operation efficiency and prolong the service life of the machine. The common faults of the vibration system mainly include that the vibration wheel does not vibrate, the vibration wheel does not move from time to time, and the vibration wheel makes abnormal noise, etc. Investigate its origin

the vibration system is the main working system of the vibratory roller. Analyzing and eliminating the faults of the vibration system is of great significance to improve the operation efficiency and prolong the service life of the machine

the common faults of the vibration system mainly include that the vibration wheel does not vibrate, the vibration wheel does not move at all times, and the vibration wheel makes abnormal noise, etc. The reason can be analyzed from three parts: electrical system, hydraulic system and vibrating wheel

1 electrical system

in general, poor quality or improper operation of the vibration switch itself will lead to poor contact of the vibration switch. Therefore, if the vibrating wheel does not vibrate, first check the vibration switch to see whether it is intact and whether there is poor contact. If it exists, it should be repaired or replaced. Secondly, check the electrical circuit for relay damage, team burnout, short circuit and line disconnection (focus on the circuit from the vibration switch to the vibration pump control solenoid valve) and eliminate them one by one

2 hydraulic system

when the hydraulic oil of the hydraulic system does not meet the requirements of pressure and flow, the oil supply of the vibration system is insufficient, and the vibration motor will not rotate or the speed is quite low. At this time, the vibration wheel does not vibrate and has a slight learning. The reasons for insufficient oil supply mainly include the following aspects:

(1) the speed of the diesel engine is too low, and the flow and pressure of the hydraulic pump cannot reach the set value. Check whether the throttle lever is in the correct position, and ask professionals to repair the diesel engine and restore the normal speed of the diesel engine of Shandong Institute of medical devices

(2) the hydraulic pump and hydraulic motor are seriously worn and the oil leaks internally. The main influencing factors are:

(a) the dimensional accuracy of hydraulic parts, manufacturing process and material selection do not meet the requirements, resulting in early wear

(b) impurities such as mechanical wear in the system cause early wear of three pairs of friction pairs: plunger and plunger hole, sliding shoe and swashplate, port plate and cylinder end. At this time, the extracorporeal circulation device can be used to queue up the mechanical wear and impurities in the hydraulic system to eliminate early wear

(c) improper use. Maintenance personnel often forget to add oil to the housing after repairing the pump or motor. The operation of the friction pair without lubricating oil will cause serious wear of the pump and motor in a short time, resulting in internal leakage. In this feature, the majority of maintenance personnel should pay attention to oiling the shell to avoid unnecessary losses

(3) failure of valves, joints and other hydraulic accessories is mainly manifested in

(a) damage or blockage of vibration on-off valve: the vibration on-off valve is damaged, resulting in no deflection of swash plate, zero displacement of vibration pump, no flow output, and the motor does not rotate and vibrate without pressure oil

(b) the pressure shut-off valve is damaged: the pressure shut-off valve is opened too early, so that the pressure of the remaining disc control circuit is relieved, the swashplate returns to zero, the system pressure cannot meet the requirements, the hydraulic oil pressure of the vibration system is too low, the vibration motor does not rotate or the rotation speed is too low

(c) the overflow valve is damaged: the overflow valve is opened too early to relieve pressure, and the system pressure cannot reach the set value. Because the oil pressure of the vibration system is too high, the rotation speed of the vibration motor is not too low

(d) the O-ring at the joint is damaged, resulting in loose sealing; The rubber and NASA are damaged by friction due to vibration; The quick change connector is not screwed in place, and the oil cannot be connected

if there is no fault in the above hydraulic parts, professional personnel should be invited to repair them. If necessary, the damaged parts should be replaced to ensure the normal operation of the equipment. If the hydraulic oil filter has a low filtration accuracy grade or the filter is damaged, and other impurities such as mechanical wear in the oil cannot be filtered effectively, resulting in other hydraulic parts being blocked or early worn, the hydraulic system should be cleaned and replaced with clean hydraulic oil and high-precision filter

3 vibrating wheel

most of the faults of the vibrating system occur in the mechanical part, and the vibrating wheel is the main fault part. The following describes the most common faults of the vibrating wheel

(1) the coupling connecting the vibration motor and the eccentric device is damaged

first of all, the spline shaft connected between the vibrating motor and the coupling is broken, which is very rare. It usually occurs on new machines, mainly because the coaxiality and perpendicularity of the vibrating wheel parts are severely out of tolerance, or because the fixing bolts of the vibrating wheel parts are broken and can be loosened, and the connecting part between Marta and the eccentric device is broken at high speed under the condition of great tea load. Secondly, the nylon sleeve is seriously worn, and the nylon sleeve of the coupling has quality problems such as material, strength or the coaxiality of the eccentric device is seriously out of tolerance, which leads to early damage of the nylon sleeve, causing no vibration, weak vibration or sometimes no vibration of the system

(2) vibration bearing

the lubrication, heat dissipation and clearance of vibration bearing directly affect the service life of bearing. If the bearing is poorly lubricated, it will be seriously worn in a very short time. The maximum allowable speed of the rolling bearing is usually determined by the allowable working temperature. For example, the working temperature of the vibrating bearing of YZ18 series roller is generally 90 ℃ ~105 (the thermal treatment process of ordinary high-speed and heavy-duty bearings can ensure the dimensional stability below 150 ℃). The unique and effective shaft cooling structure with lubrication will drag, straighten, and Stabilizing tension and other functions; Shouhe of roller type (divided into horizontal type and vertical type); The clearance of the bearing before high-speed rotation and installation must be greater than the working clearance, and a large radial clearance is required

the early damage of the vibration shaft is largely due to the quality problems of the vibration bearing itself: the bearing actively guides qualified enterprises to carry out the development and production of new military materials. The wear resistance, hardness, dimensional accuracy and heat treatment process do not meet the requirements, and the bearing ring is burned out; Or the bearing was not assembled according to Fucheng, and the bearing was damaged during assembly, and the lubricating oil did not meet the requirements, resulting in early damage to the bearing; Or because the axial clearance is too small, the high-speed rotation of the bearing generates heat, which reduces the axial clearance, presses close and wears the cage

secondly, the specification of the selected bearing is incorrect. Compared with ordinary high-speed and heavy-duty bearings, the vibration bearing has higher requirements for performance parameters, and the radial clearance of the bearing is larger than that of ordinary heavy-duty bearings. If the bearing brand and specification provided and recognized by non host manufacturers are rashly selected, vibration failure will occur. If the clearance of the bearing is too small, after working for a period of time, the bearing will heat up, which will reduce the radial clearance, cause wear between the inner and outer rings of the bearing and the rollers, and the bearing will be stuck. At this time, stop the machine to let the bearing work after heat dissipation, and vibration will appear again, and the vibration will disappear after a period of time. However, because the bearing wear will be accompanied by slight noise, for a long time, the noise of the vibrating wheel will increase, accompanied by howling, and finally the vibration will completely disappear, the bearing will be completely burned, and the matching parts will be taken 4140 through most screws H. T. the steel bottom is damaged. If the bearing clearance is too large and the axial and radial fit is not accurate, the bearing will also suffer early wear and shorten its service life. Therefore, when choosing key accessories such as vibration bearings, users must choose the brands and specifications provided by the manufacturer or recognized by after-sales personnel, which will cause serious consequences and unnecessary economic losses

(3) amplitude modulation device

most of the vibratory rollers used now are dual frequency and dual amplitude and adjustable. The amplitude modulation device is composed of left and right. For example, the 18t series vibratory roller, which is mainly used to compact the subgrade, relies on the positive and negative rotation of the eccentric device to achieve different amplitudes. If the amplitude modulation device of the vibrating wheel is damaged, a large impact sound will be generated during vibration operation (the impact sound is not very obvious when an amplitude modulation device is damaged), and a clear and continuous impact sound will be heard during the starting or stopping of vibration. The amplitude of vibration is disordered, sometimes absent, sometimes large and sometimes small. When the amplitude modulation device fails, the damaged parts should be abstracted in time

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