| Top Drive Drilling System (TDS), since it was born in1982, have been widelyused in marine and land rigs. Compared with conventional drilling tools, TDS ismore secure and reliable, and especially suitable for high demand and complexconditions drilling such as deep, ultra-deep wells, horizontal wells and inclinedwells.Currently, there are4types of TDS:①type of hydraulic drive TDS;②type ofAC-SCR-DC electric drive TDS;③type of AC variable frequency inductionmotor drive TDS;④type of AC frequency permanent magnet motor drive TDS.Mainstream products at home and abroad, such as TDS series of Varco, DQ70BSseries of Beijing Petroleum Machinery Factory are using the AC variable frequencyinduction motor.AC variable frequency technology is maturely applicated in TDS. As theproportion of electro-hydraulic control technology development, electro-hydraulicproportional control technology, as represented by hydraulic technology, applied toTDS, has its unique advantages, will be the future development trend.We believethat, make the electro-hydraulic proportional technology used in TDS, that is to saythe design of a hydraulic drive TDS can greatly improve the technical level of China's scientific drilling, and make a profound impact on China's diamond diggingmachinery, also has the important strategic sense.Electro-hydraulic proportional control technology, as represented by hydraulictechnology, applied to TDS, has its unique advantages. The topics raised to design ahydraulic TDS that has similar performance to7000m AC variable frequency TDS,and able to meet the requirements of the implementation of the diamond drillingprocess.TDS design based on specific requirements are as follows:(1) Formationconditions: any soft to hard strata;(2) Drilling methods and techniques: diamonddrilling, roller cone drilling;(3) Hole depth:7000m;(4) The final hole diameter: Φ152;(5) Drill pipe diameter:Φ89,Φ114,Φ127;(6) Full hole continuous coringand logging;(7) Core diameter: greater than Φ90. By reference to domestic andforeign mainstream7000m TDS equipment, And the specific requirements of coredrilling, the main working parameters of the hydraulic TDS should be determined asfollows:(1) Rotary speed is0~300rpm stepless speed regulation;(2) Drilling torqueis50kN m;(3) Power to850kW.This article has carried on the preliminary design of hydraulical drive TDS,named for the SP-70hydraulic drive TDS. Dimensional solid model and Hydrauliccircuit diagram of SP-70hydraulic drive TDS have been built. A carrier is providedfor the TDS further design and optimizationTake realizes the function of TDS, faucet-drilling motor assembly, guide blocksand parallelogram mechanism assembly, pipe handler and balance system aredesigned. The various parts fit together and hydraulic TDS is formatted.For controlling the motion of mechanical systems to achieve, spindle rotationsystem circuit, tilt mechanism circuit, rotary power head hydraulic motor controlcircuit, brake circuit, IBOP control circuit, back clamp cylinder control circuit,balance cylinder control circuit and stretching cylinder control circuit are designed,and the above circuits are integrated.A decomposition of the TDS action has been conducted, and the movementanalysis to the decomposition movement has been carried on. The twisted pointforce curve of related parts is obtained. A basis for optimize design, finite elementanalysis and the selection of hydraulic cylinders have been provided.Reaction force curves of twist points and their roles are listed in the following:(1) Reaction force curves of twist points of swing cylinders of side swing elevator.It can be used for the selection of the cylinders;(2) Reaction force curves of twistpoints of rings of side swing elevator. It can be used as load conditions for the finiteelement analysis of the rings;(3) Reaction force curves of twist points of extensioncylinders of extension mechanism(The parallelogram mechanism). It can be used forthe slection of the extension cylinders;(4) Reaction force curves of twist points ofextension rods of extension mechanism. It can be used for further design of the rod parts and strength check of the finite element analysis;(5) Reaction force curves oftwist points of clamping cylinder of elevator. It can be used for the selection of theclamping cylinder after revised;(6) Drive motor torque curve of power rotatinghead. It can be used for the slection of the drive motor and for the strength check ofrotating head gear pair.During the implementation of the dynamics analysis, we realized: dynamicsanalysis software should be flexiblely used. At the same time, address its limitations,and use more tools for simulation analysis.The system simulation model of spindle drive chain has been established andthe system simulation analysis has been conducted on it. Following conclusions hasbeen obtained:Constant power control and constant torque control can be realized on thismodel;The simulation analysis of normal drilling conditions and the conditions ofmeeting stuck drill has been conducted. During normal drilling, under the conditionof keeping rotational speed, the system oil duct automatically adjust the workingpressure to enable the torque to achieve the load intensity, to ensure the normaloperation of the system. Under the condition of load mutation, system driving torquerises to maximum safe torque of the drill pipe, then safety valve overflows, the driveload is no longer rising, ensure that the drill pipe column is not broken.At last, we proved that the spindle drive system can meet the designrequirements with the good stability and security.Applied the finite element analysis software ANSYS to analyze the main partsin the case of the static mechanical analysis, fatigue analysis and vibration (modal)analysis. The spindle strength has been verified. Vibration analysis of gear pair hasbeen conducted. Conclusions of FEA are listed as following:Static mechanical analysis: use the designed spindle model for simulation; setmaterial properties, contact and constraints between the parts; the added loads aremaximum static load and maximum torque during the TDS working, they are 431.2kN and80kN m. Get a maximum stress of392MPa. Maximum stress occurs atthe connecton place of the locking bodies and spindle;Fatigue Analysis: as load act on the spindle is not always static load duringworking, most of the time, the spindle is in the state of load fluctuation. Therefore,fatigue analysis of the spindle has been conducted. During the analysis, loadfluctuation has been settled, material stress life curve (S-N curve) were calculatedand set; results of fatigue analysis showed that spindle stress amplitude is not large,only39MPa; spindle life can reached to5.208e6cycles, greater than the designlife(5×104cycles, that is5years);Gear pair in the course of their work, may be subject to the effects of vibration.Therefore, vibration analysis of gear pair has been conducted.The first6naturalfrequencies and mode shapes of the gear pair has been provided. Duing the design ofthe gear system, gear natural frequencies and mode shapes shouled be considered,make natural frequencies of the gear away from the operating frequency to avoidresonance.In the present paper, the full hydraulic pressure top drive design is still stay inthe preliminary design stage, of course, there are many defects and needs the furtheroptimization design. In the course of movement analysis, the friction between theparts may influence the results of the analysis due to the limitation of my experienceand the software, adding up the lacking considering. So we should consult more dataand combine with the spot experience to amend it. During the design process, weprocceeded a large mount of simulation analysis without the support of theexperiments. In the physical prototype design process, we should add moreexperiment content. The application of virtual prototype technology can reduce theuse quantity of physical prototype and reduce the cost, but it can not fully replace thephysical prototype.
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