Adjustment and common faults of main devices of th

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Adjustment of main devices of cement concrete paver and analysis of common faults

I. adjustment of main devices

1. Adjustment of spiral distributor

the installation height of spiral distributor must correspond to the thickness of the paved road. Generally, the bottom edge of spiral blade should be 50 ~ 100mm higher than the formed road surface, so as to reduce the distribution resistance of spiral and ensure sufficient pre vibration. If the height is too high, it will increase the pushing resistance of the scraper. In addition, the height of the cement concrete pile should not exceed the upper edge of the spiral blade as far as possible, preferably 1/3 ~ 1/2 of the height of the distributor

2. arrangement and adjustment of vibrators

(1) spacing of vibrators

the spacing of vibrators should ensure that there is a certain overlap between the effective vibration forces of the two rods during the paving process of the machine. Generally, the distance between rods is 450 ~ 500mm, and the distance between rods on both sides and side sliding formwork should be 200 ~ 250mm. In order to ensure the quality of cement concrete pavement and improve the compactness of pavement, the spacing of vibrator should not be too large

(2) adjustment of vibration frequency of vibrator

the vibration frequency of vibrator has a great impact on the strength and flatness of cement concrete pavement. The higher the vibration frequency, the better the effect of slurry extraction and compaction; However, if the frequency is too high, it will lead to excessive bow sinking and slurry lifting, and the segregation of sand and gravel, which will affect the strength of the pavement and the stability of the edge. The frequency of the vibrator is determined by the amount of oil supplied by the throttle valve to the vibrator, and each vibrator can be adjusted separately. The vibrator used by the slip form paver is a high-frequency vibrator, whose amplitude is generally about 0.3mm, and the maximum vibration frequency is 200Hz, which can be adjusted continuously individually. Generally, it should be adjusted within the range of 100 ~ 183hz during construction. According to the vibration process principle of concrete, low-frequency vibration has a greater vibration effect on large aggregates, while the vibration of small particle size materials depends on high-frequency vibration

(3) adjustment of vibrator position

generally speaking, the deeper the vibrator is inserted into the concrete, the better the vibration effect. However, during the paving process, the vibrator always advances along a straight line, and the coarse aggregate can only be filled by mortar after being pushed away, and the shrinkage rate of mortar is greater than that of cement concrete, so the initial setting agent will crack along the direction of the vibrator, and then these cracks will be widened due to the shrinkage of concrete, resulting in the longitudinal Slab Breaking of concrete

3. Relevant matters of the automatic leveling system

(1) a sensor tracks the change of the height of its corresponding crawler outrigger, so the lifting and lowering of the outrigger must be reflected to the sensor in time. Therefore, the installation position of the sensor should be as close to its corresponding outrigger as possible; The maximum distance (longitudinal or transverse) between the sensor and the outrigger must be within the specified range, and the length of the sensor installation cantilever cannot be arbitrarily extended; The sensitivity of the sensor is determined by the opening of the throttle valve on it, and the sensitivity setting of each sensor should be the same

(2) when the paver is in the waiting state, the automatic leveling system weight: 260kg system should be turned off, and the leveling cylinder should be locked to lock the elevation of the concrete slab in a certain state

(3) if the sensor spool, lock valve or solenoid valve is stuck, the leveling action cannot be carried out, affecting the flatness of the road, so the cleanliness of the hydraulic oil must be maintained

(4) the outrigger leveling cylinder and hydraulic lock should be prevented from being under high pressure for a long time. During shutdown, the machine frame should be supported by an iron cylinder at the crawler

4. pressure adjustment of automatic trowel plate

large slip form pavers are generally equipped with automatic trowel plates with adjustable pressure. The standard length of the trowel plate is 3.66M and the width is 20cm. It is beneficial to eliminate the defects caused by small bubbles on the surface and the stones dragged by the screed, and can play a part of the role of slurry lifting to ensure the excellent longitudinal flatness of the road surface; During construction, the pressure of the plastering plate should be adjusted at any time according to the changes of the longitudinal slope of the road surface. Zhou Yufei, director of the material Department of the first automobile technology center of China, should have a small pressure rather than a large one. Excessive pressure will make the longitudinal and transverse flatness worse

II. Common faults

1. Screw distributor fault

if the oil pressure of the screw distributor is too high and does not rotate during use, the reasons may come from four aspects

(1) the bearings at both ends of the screw distributor are damaged. It is generally caused by the damage of the oil seal and dust seal sleeve outside the bearing. The concrete mortar enters into it, causing the screw distributor to be stuck or the resistance is too large, and the bearing will be damaged in serious cases. At this time, it is only necessary to replace the bearing, oil seal and dust seal sleeve and add new lubricating oil

(2) the chain is too long. When the chain is stretched to a certain extent, the chain teeth will be stuck by the chain gear box housing. At this time, it is necessary to replace it and fill it with lubricating oil

(3) planetary reducer is damaged. Remove the screw distributor and the cover of the chain gear box, and turn the driving sprocket. If it cannot turn, just remove the driving gear and observe the damage of the planetary reducer. The damage is generally caused by the poor processing quality of individual gears and gear rings, and the assembly needs to be replaced

(4) hydraulic pump and hydraulic motor failure. If the hydraulic pump is damaged, the indicated value of the hydraulic gauge is low; If the hydraulic motor is damaged, the indicated value of the hydraulic gauge is also low, and the damaged side has no action. Replace the assembly in case of any of the above conditions

2. Vibration system failure

(1) the vibrator does not vibrate

it shows that the machine vibrates well when it is unloaded, but the vibrator stops vibrating after working for 10min or even longer. The possible reason is that the bearing is stuck; The motor driven gear bearing is stuck; The connecting fork of the motor driven gear shaft is broken; The steel wire shaft in the connecting shaft connecting the motor and the eccentric is broken

the troubleshooting method is to check whether the motor housing is damaged. If not, replace the gear pair and sealing ring, reinstall the steel wire shaft, and replace all bearings. The fault can be eliminated

(2) vibration of the vibrator, but this kind of lattice greatly increases the weight of the aircraft, and the force is insufficient

the working frequency of the vibrator is generally 6000 ~ 11000r/min. In the construction process, sometimes the vibration of the vibrator is weak, and even adjusting the frequency modulation knob is useless. At this time, the vibrator should be replaced. The method is to unscrew the centrifuge shell of the damaged vibrator, extract the centrifuge, check the bearings at both ends of the centrifuge, the supporting bearings and sealing rings of the output shaft of the vibration motor, and then replace and reassemble it

the above faults are generally caused by the failure to fill the bearing with grease in time, which should be replaced in time according to the service life of the grease; The vibrator with weak vibration should be inspected and repaired as soon as possible, so as to protect the vibration motor from damage. Do not increase the vibration frequency when the vibration is weak, which will accelerate the damage of the vibrator

3. hydraulic system failure

the project was completed by 30 technicians including Manuel Torres, the founder of mtorres company, in the past six months, mainly manifested as: the hydraulic cylinder of side formwork, virtual square control board and vibrator beam was not lifted in place or could not be lifted. The main reason is that the solenoid valve does not work or the control lever circuit is faulty; The pump oil pressure is abnormal, and the oil is deteriorated; Overflow valve is damaged; The hydraulic cylinder leaks oil or the oil pipe is damaged. If the hydraulic cylinder is broken, check and repair the piston, cylinder block and oil seal. The reason for the excessive resistance of the oil circuit may be that the piston rod is stuck by the residual concrete block. At this time, it should be cleaned immediately, and a small amount of grease should be applied at the hydraulic cylinder port, and the piston rod should be moved several times to make it return to normal work

hydraulic system faults are generally manifested as: insufficient vibration frequency of vibrator, decreased vibration force, increased oil temperature, increased noise, etc. At this time, we should first consider whether the oil volume of the system is sufficient. If the system works normally after refueling, but the above symptoms occur repeatedly after a period of time, it may be caused by serious leakage of hydraulic oil in the system, and a comprehensive inspection must be carried out. The internal leakage of the system may be in the solenoid valve and the main pump. For this reason, first check the solenoid valve

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