(1) Brief introduction of hoisting mechanism (RCS) RCS hoisting mechanism has the characteristics of large lifting capacity, stable operation, fast operation speed and wide speed regulation range, and is widely used in large and medium-sized tower cranes at home and abroad. As shown in figure 6- 1
1. Stop 2. Drum number three. Reducer 4. chassis
5. Motors (two sets) 6. L distribution box 7. Resistance box 8. Maintain equipment foundation
The mechanism consists of two identical winch motors with disc brakes connected with a reducer (first-stage cylindrical gear+bevel gear, the speed ratio is 35.6). The reducer is floatingly installed on the reel shaft to drive the wire rope reel, and the two motors are controlled by an electrical control system composed of AC relays, AC contactors and other elements, so as to realize the smooth and high-speed rise or fall of the heavy objects. (2) Maintenance and maintenance of hoisting wire rope?
The installation, maintenance, lubrication and scrapping of wire rope shall be carried out according to the instruction manual and relevant standards.
Once the multi-layer winding steel wire rope is tangled, it will form transverse extrusion between steel wires, and the outer steel wire rope will easily crush the inner steel wire rope, thus forming a kink between layers. In severe cases, multi-layer mixed extrusion will be formed in a certain area along the length of the drum, which will completely disrupt the rope arrangement order and sometimes even cause rope breaking accidents. Therefore, the rope arrangement device on the tower crane must be flexible and reliable, and the rope arrangement shaft must be kept clean, cleaned and lubricated every day, so that the rope arrangement wheel can move freely, and the deflection angle of the wire rope when winding into or out of the pulley cannot be too large, so that the wire rope can be arranged neatly on the drum.
2. luffing mechanism (DTC)
1). Brief introduction of DTC pitching mechanism (as shown in Figure 6-2). The pitching mechanism includes a single-speed torque motor with an eddy current brake at the shaft extension end and a DC disc brake at the end. The reducer is connected with the planetary reducer in the drum through a transmission shaft, and the transmission shaft is connected with the drum through bolts to drive the front rope and the rear rope of the drum, so that the horizontal luffing of the luffing trolley is realized through electrical control.
1. Drum and reducer housing 2. Motor eddy current brake
3. Brake of motor 4. Manually release the handwheel of the brake.
5. Nut M8 locks the handwheel in working condition.
6. Spring cylinder for adjusting the pressure of brake spring
7. Insert the locking screw pin of the brake disc into the third and fourth holes of the brake disc.
8. Spline sleeve 9. drive shaft
The drum diameter of this mechanism is 360mm, and the drum length is divided into L=5 10mm and L=590mm, which are used for tower cranes with 60m and 70m arms. The maximum traction of the mechanism is 600kg, and the maximum output torque of the drum is11500 n.m. ..
According to the different arm lengths, the lengths of the front and rear ropes of the mechanism are as follows:
arm
50 meters
60 meters
70 meters
Front rope length
95 meters
1 15m
135m
Rear rope length
65 meters
70 meters
80 meters
(as shown in Figure 6-3) Check the clearance of the brake. The normal state should be 0.5 ~ 0.8 mm Due to long-term work, this gap value changes, which will cause noise, smoke of friction plates and rapid wear or burning of brake coils. The way to adjust the clearance is to take out the locking screw on the brake disc, rotate the brake disc through four holes, and install the locking screw to ensure that the clearance remains unchanged. The setting of the braking torque of the brake is realized by adjusting the compression of the spring. The appropriate torque can ensure that the car does not slip under heavy load and it is not difficult to pull in.
3. Rotary mechanism (1) Brief description of rotary mechanism The rotary mechanism is composed of torque motor and planetary reducer (as shown in Figure 6-4). choose
Electronic voltage regulating and speed regulating system. By adjusting the power supply voltage and eddy current of the torque motor stator
Realize speed adjustment. The motor with wind vane brake is used for windproof parking in working state and non-working state.
In order to reduce wind resistance and ensure the safety of tower crane, the boom rotates freely according to the wind direction.
1: torque motor 2: planetary reducer 3: wind vane brake 4: rotating ring gear
Use and maintenance of slewing bearing.
1). Before the tower crane leaves the factory, the slewing bearing is coated with a small amount of No.2 lithium-based lubricating oil in the raceway. When enabled, users
New grease should be added according to different working conditions.
2) Under normal working conditions, the ball slewing bearing is lubricated every 100 hour, and the roller slewing bearing is supported.
Bearings should be lubricated every 50 hours of operation. In tropical, high-temperature, dusty, temperature-changing areas and
In the case of continuous operation, it should be lubricated once a week. Before and after the machine stops running for a long time, it must also be replenished.
New grease. Every lubrication, the raceway must be filled with grease until it oozes from the seal.
When injecting grease, rotate slowly to make the grease evenly filled.
3). Clean the gear surface sundries every 10 working days and apply grease. Grease can be selected according to the following table:
supporting structure
Conditions of use
Lubricant shell
Grease type
name
Consistency grade
Plastic isolation block
Rubber gasket seal
Low temperature and normal temperature
Humidity -40℃~+60℃
rollaway nest
Extreme pressure lithium grease
1~2#
gear
Graphite calcium base grease
ZG-S
Metal isolation block
labyrinth seal
High temperature and humidity
40℃~ 140℃
rollaway nest
Extreme pressure lithium grease
1~2#
M0S2 composite base grease
2#
gear
No.4 high temperature grease
4#
High temperature and humidity
80℃~ 180℃
rollaway nest
M0S2 composite base grease
2#
gear
high temperature grease
4#
Normal temperature, seawater corrosion resistance.
-50℃
rollaway nest
composite aluminum base grease
2#
gear
Aluminum base grease
4#
4). After the slewing bearing runs 100 hours, the pre-tightening force of bolts should be checked, and then every 500 hours, and sufficient pre-tightening force must be maintained. In general, bolts should be replaced every 7 years or after working 14000 hours.
5). Pay attention to the operation of slewing bearing when using. If the noise, impact and power suddenly increase, stop the machine immediately for inspection, troubleshoot and disassemble it if necessary.
6) When in use, prevent the bearing from being exposed to strong light and direct sunlight. It is forbidden to directly flush the slewing bearing with water to prevent water from entering the raceway and prevent hard foreign objects from approaching or entering the meshing area.
Always check the integrity of the seal, replace it in time if it is damaged, and reset it in time if it falls off.
4. The walking mechanism of 4.RT443 walking mechanism is mainly composed of four driving trolleys, each driving trolley includes a two-speed squirrel cage motor, and a double-acting disc brake is installed at the tail. The extension end of the shaft is connected with the reducer with the speed ratio of 140.2 through the spline shaft, and directly engages with the driving wheel to realize the walking movement of the tower crane. Each car is equipped with a track clamp to fix the tower crane when it is not working. Among the four trolleys, only one trolley is equipped with a travel limit switch to limit the working range of the tower crane. The motor model used in this mechanism is YTZE112m-2/4; The wheel diameter is 365mm；; The speed ratio of planetary reducer is I= 140.2. The rear of the motor is equipped with a double-acting disc brake, which has a delay effect when starting or braking to reduce the impact of tower crane starting or braking. The motor and the reducer are installed in a floating way, the drive axle is splined with the output shaft of the reducer, and the reducer is hung on the trolley with a buffer spring rod to reduce the impact when starting.
The driving wheel and the driving shaft are closely matched, and the connection is simple. The reducer is driven by involute planetary gear.
The mechanism can be used on both straight rails and curved rails, but the walking speed should be controlled at 1 before the curved rails run.
When the main power supply is cut off, the brake block is pushed by the spring to produce the maximum braking torque. When the cart is running, the two yokes are energized at the same time, the brake is attracted and clings to the yokes, the spring is compressed, and the brake is opened.
When the car brakes, one yoke is de-energized. At this point, the tower crane began to slow down and the other yoke continued to be electrified. After deceleration for 5-7 seconds, when the speed drops to a lower level, the power is cut off and the brake block is braked to stop the tower crane at a low speed.
Please adjust the clearance of the yoke according to the requirements of the manual.
Pay attention to when walking in the tower crane:
(1) whether the cable reel is stable to ensure that the cable will not be twisted, worn, accumulated or broken. If there is accumulation or it is too serious, adjust the friction torque of the cable reel according to the provisions in the manual.
(2) Whether the deformation of track, sleeper, pad, etc. meets the standards to prevent rail gnawing or other accidents.
5, the use and maintenance of hydraulic jacking system,
The hydraulic system of ST series tower crane is mainly composed of hydraulic pump station, jacking oil cylinder and connecting hose.
The hydraulic pump station consists of oil tank, oil filter, motor, oil pump, combined reversing valve, pressure limiting valve and pressure gauge.
Basic technical parameters:
Hydraulic oil N46 antiwear hydraulic oil or 40 thickening oil
Tank volume130l
Motor power 15KW
The set pressure of the safety valve is 44MPa.
The maximum working pressure of jacking is 40MPa.
The maximum working pressure is reduced by 6.5MPa.
The pressure of balance valve is 2.5MPa.
Oil pump flow 22L/mm
Cylinder inner diameter φ 180mm.
Piston rod diameter φφ 125mm.
The maximum jacking force is 100t.
The jacking speed is 0.8-0.85 mm/min.
The return speed can be adjusted within a safe range.
Cylinder stroke1600mm
West Germany High Pressure Hose Standard: 40- 13-60
H-type high pressure hose assembly 4m
principle of operation
After the motor is started, the coupling drives the oil pump, which makes the oil pass through the coarse filtration from the oil tank, and the combined reversing valve and high-pressure hose assembly reach the jacking oil cylinder. The set pressure between the oil pump and the combined reversing valve is 44 MPa, and the jacking overflow valve in the combined reversing valve is set to 40Mpa (which can be set by users according to their needs), the descending overflow valve is set to 6.5Mpa, and the balance valve is set to 2.5Mpa before leaving the factory.
When the combined directional control valve is in the middle H position, the P port is communicated with the T port, and the hydraulic oil output by the oil pump directly returns to the oil tank through the combined directional control valve, at this time, the hydraulic system is in the unloading state.
The combination directional valve is in the left position as shown in the figure (when the handle of the combination directional valve is lifted), and the hydraulic oil output by the oil pump passes through the combination directional valve P→H→ high pressure hose assembly → two-way hydraulic lock, and then enters the rodless cavity of the oil cylinder, and at the same time, the two-way hydraulic pressure is opened, so that the piston of the oil cylinder moves down; The hydraulic oil with rod cavity in the oil cylinder flows back to the oil tank through the bidirectional hydraulic lock → high pressure hose assembly → combination valve change B→T, and the oil cylinder is jacked up. The jacking speed is determined by the flow rate of the oil pump.
When the combined directional valve is in the correct position as shown in the figure (when the handle of the combined directional valve is pressed down), the hydraulic oil output by the oil pump enters the rod cavity of the oil cylinder through the combined valve P→B→ high pressure hose assembly → bidirectional hydraulic lock, and at the same time, the bidirectional hydraulic lock is opened to make the piston of the oil cylinder move upward; The hydraulic oil without rod cavity in the oil cylinder flows back to the oil tank through the bidirectional hydraulic lock → high pressure hose assembly → combined directional valve H→T, and the oil cylinder rises and falls. The descending speed is determined by the throttle valve of the regulating cylinder. Use and maintenance
1). Crimp the motor power cord correctly, so that the motor can rotate counterclockwise when viewed from the axial direction (inching to check the motor steering); Open the cover of the hydraulic air filter and inject clean hydraulic oil of the specified brand into the oil tank from the hydraulic air filter; Connect the pipeline of the hydraulic jacking system according to the schematic diagram of the hydraulic system and tighten the joint; Test run, pay attention to whether the hydraulic pump station works normally. At first, the cylinder may shake. At this time, screw the bleeder screw to the left at the bleeder hole of the oil cylinder, spray a little oil and run it several times. If there is no shaking, screw the deflation screw to the right. Check the pressure of jack-up relief valve in hydraulic pump station. (The jack-up relief valve has been adjusted to 40Mpa before leaving the factory, and it generally does not need to be adjusted when working. However, it can also be adjusted to the required pressure as required, and the relief valve is reduced to 6.5Mpa), that is, the pressure after the cylinder is fully extended and fully retracted is observed. After the above work is completed, it can be put into normal work.
2). Although the fuel tank has been filled for the first time, a part of it enters the fuel tank after starting, and the amount of oil in the fuel tank decreases. Therefore, when the hydraulic jacking system is put into operation, hydraulic oil should be added to the oil tank until the upper limit of the liquid level gauge; Check the cleanliness of hydraulic oil regularly, generally once every six months or after working for 2000 hours. It can also be advanced according to the specific situation. If it is still clear, then keep it; If it is milky white, solidified and turbid, replace it with new oil; In order to protect the sealing ring of the oil cylinder, the dirt on the piston rod should be cleaned frequently; After work, it is best to cover the hydraulic pump station with something like plastic cloth to prevent water leakage from polluting the oil and prolong its service life.
Causes and elimination of common faults
1). When the oil cylinder descends, it will shake and vibrate greatly, and in severe cases, it will shake the tower.
Cause: Due to improper adjustment of throttle valve in oil return circuit.
Troubleshooting: Adjust the air throttle valve to the best state specified in the manual. If the throttle position of the cylinder block is not concentric with the thread, it cannot be adjusted.
2). The connector sleeve is damaged?
Reason: Because the manufacturing process of the ferrule is not guaranteed.
Elimination method: replace the new joint or weld. Namely nut and straight-through welding. (At this time, the joint cannot adjust the direction of the tubing).
3). The cylinder keeps falling and slipping?
Reason: Because the exhaust of the two cavities of the oil cylinder is not clean; Poor sealing; Hydraulic oil is not clean.
Elimination method: exhaust the air in the oil cylinder; Ensure the seal between the control piston and the check valve; Always check the cleanliness of oil to ensure the sealing of oil tank; The control valve in the hydraulic pump station should be adjusted accurately.
Matters needing attention
The high and low pressure interfaces of hydraulic jacking system cannot be reversed. When the oil cylinder is loaded, it is not allowed to adjust the throttle valve. ※: Carefully adjust the high-pressure throttle.
Note: Never use emulsified hydraulic oil, which may damage the internal fittings of the pumping station. ※.
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