The localization transformation of Hitachi S320 drilling rig

The S320 drilling rig produced by Hitachi Construction Machinery Co., Ltd. has aged in performance and cannot meet the requirements. The modification of this machine is as follows: separate the main body of the drilling rig from the pump suction reverse circulation device to make them work independently, combine the original machine turntable device with the hydraulic pump, and eliminate the transmission shaft device with frequent faults. The original sand and gravel pump, vacuum pump, motor and distribution cabinet were rearranged and installed on the original base. After processing and repair, a new vacuum pump suction and reverse circulation device was formed.

1. Hydraulic system

After more than 20 years of use, the system of this machine has been severely worn and aged. The system pressure can no longer drive the turntable to idle. The specific problems are as follows: the gap between the hydraulic pump head and the distribution plate has increased, the groove is deep, and it is basically unusable. The valve needle and valve seat in the pressure regulating valve group are severely worn, the spring has undergone severe plastic deformation, the axial oil seal of the motor leaks oil, and the oil pressure chamber and the distribution device have rusted due to long-term parking. The rubber hydraulic oil pipe is aging and leaking oil.

Each component of the hydraulic system is cleaned one by one, inspected and repaired. For the parts that cannot be repaired, domestic production transformation is carried out to ultimately achieve or approach the designed performance. For instance, the hydraulic pump head is modified for domestic production, the distribution plate is ground and repaired, and then assembled after grinding. Grind the valve seat, valve needle and spring to domestic production. Before assembly, grind the valve needle and valve seat against each other, disassemble and inspect the motor, remove rust spots, and grind the journal according to the domestic standard oil seal size. All rubber hydraulic pipes are domestically produced, and domestic standard quick-change couplings are adopted. After the transformation, the maximum output pressure value at the outlet of the hydraulic pump set is 23.5MPa. The pressure regulating range of the pressure regulating valve group is 3.5-23.5MPa.

2. Power turntable

The turntable is loose and makes abnormal noises. The specific problems are: eccentric wear of the square clamp at the center of rotation, wear of the tooth edge of the transmission bevel gear pair, large meshing clearance, severe wear and rust of the turntable's slewing bearing, and aging and rusting of the lubricating oil pipe.

In response to this situation, new square clamps were mapped and welded to manufacture. The meshing clearance of the gear pair was adjusted by reducing the gasket to achieve the best meshing state (refer to the "cone Angle" tooth adjustment specification for the rear axle of automobiles). Grind the raceways according to their conditions. Replace with domestic standard steel balls (18.5mm produced by Harbin Bearing Factory), and process the steel ball spacer with domestic nylon bar stock. Rearrange the lubricating oil pipeline with domestic purple copper tubes and replace the oil cups.

3. Lifting

The original lifting mechanism of the machine was designed for independent lifting of the crawler crane. It is proposed to be modified to use a winch to achieve active lifting of the drill pipe through the gantry. Based on the design principle of the gantry of the GPS20 drilling rig for prospecting in Shanghai, an optimized combination was carried out. The base was made of scrap steel sections, and the A-shaped drill tower was composed of scrap RCF drill pipes. Two winches and two sets of pulley blocks were adopted, and the pulley blocks achieved sliding displacement on the upper crossbeam.

4. Vacuum system

The original machine adopted a vane-type water-cooled vacuum pump. After the transformation, a domestic vacuum pump was used instead. The vacuum pump meets the vacuum degree requirements for suction operation :-0.08-0.10MPa.

5. Due to the continuous erosion of drill cuttings and mud, the pump casing, impeller, tongue door, tongue door seat, etc. are severely worn. The fit clearance exceeds the limit, and the pump suction efficiency has dropped significantly, which can no longer meet the needs of normal production.

Repair measures: Weld and machine repair the impeller and pump casing to restore the design dimensions. The tongue door and the tongue door seat were redesigned and manufactured (forged from high-quality 45 # carbon steel). Domestic design and manufacture of floating sealing rings (using bearing steel); The domestic design of the sealing ring seat (supported and sealed by standard elastic oil-resistant rubber rings).

6. Power distribution system

According to the actual needs of motor configuration, new electrical components are adopted to design and manufacture distribution cabinets and operation cabinets respectively. And install leakage protection devices, full-machine power-off buttons, voltage and current indicators, and low-voltage operation buttons.

7. Structural layout

The original design transmitted the power of the motor to the hydraulic pump set, vacuum pump and sand and gravel pump respectively through the clutch attached to the intermediate drive shaft. The turntable is an independent unit and is remotely connected to the main machine through hydraulic rubber hoses. It is driven by a single motor and has a relatively conservative design power, which sometimes leads to insufficient power performance. The intermediate transmission shaft is supported and fixed by both ends, which is highly flexible and has high requirements for the supporting bearings at both ends. When the bearings are damaged, replacement is complex (the sprocket needs to be disassembled). The clutch is axially installed on the central shaft. The replacement of the clutch plate is complicated, and the replacement of the vulnerable part, the V-belt, requires the disassembly of the support seat.

After the transformation, the intermediate transmission shaft and axial clutch device of the drilling rig were removed. Different motors were selected for driving according to the power of the hydraulic pump, vacuum pump and sand and gravel pump. The hydraulic pump set, drive motor, two winches, turntable, distribution cabinet and operation cabinet were installed on the lifting seat. Integrate the sand and gravel pump, vacuum pump, air storage tank, vacuum pump motor, sand and gravel pump drive motor and distribution cabinet into an independent system - the vacuum pump suction and reverse circulation device.

After the transformation, the failure rate of the drilling rig has significantly decreased, and maintenance has become more convenient. It has a strong external replacement capacity. The drilling tower, turntable, hydraulic pump set and hoist are organically combined into one unit to form the main unit, enabling the main unit to operate independently. Especially when performing air-lift reverse circulation drilling or forward circulation drilling, only a 40kW motor is needed to drive the hydraulic pump set to run, and the pump suction reverse circulation device can be idle. This will reduce energy consumption and minimize equipment wear and tear.