Drilling machine "SBSH-250MNA-32"

Contents

Special part

1. Purpose of SBSH-250MNA- machine

2. Arrangement and operation of components of SBSH-250MNA- machine

3. Analysis of the operation of the electric drive of the drill head

4. Description and analysis of rotation hydraulic drive operation

5. Calculation of proposed hydraulic drive

Analysis of the operation of the electric drive of the drill head

1.3.1 Description of rotator operation

Drilling tool is rotated by drilling head through drilling steel. The drill head consists of:

an electric motor transmitting torque to the reduction gear;

a two-stage reduction gear with a gear ratio of 11.05, designed to transmit torque from the electric motor to the tire coupling;

a tire-gear coupling for transmitting torque from the electric motor to the support assembly and receiving the impact load during drilling, thereby preventing the reduction gear with the electric motor from shocks and vibration arising during drilling;

support unit intended for transfer of axial force and torque during drilling to drilling steel and further to bit, as well as supply of air-water mixture for cooling of bit and cleaning of well from drilling fines.

1.3.2 Description of operation of the rotary motor motor

To date, the rotation drive of domestic machines of the type SBSH250MNA32 is made on the basis of the use of a DC motor of the type DPV52 and a thyristor converter unit of the type TEZ160/460 P. The engine DPV52 has special independent excitation windings for a voltage of 80110 V. All four excitation coils are connected in series and have two output ends. The rated motor armature voltage in the G- D system differs from standard voltages 220 or 440 V. The coils of the additional poles are connected in series and connected to one side of the armature winding, the output used in the mechanism control system is given from the point of connection of the coils with the armature. Motor pole coils can have class F along with insulation class H, mandatory for tropical design. The motor provides a high starting torque value also called a stop. Engines operate at inclinations up to 15 degrees with increased vibrations, dust and humidity. The motor DPV52 of the drilling stand rotator is controlled by the unit TEZ160/460 P. The unit receives power from a three-phase AC network with a voltage of 380 V. The converter makes it possible and performs two-zone control of its rotation speed in the motor drive system by changing the excitation, depending on the voltage current values ​ ​ in the armature circuit. Reversal of motor rotation is performed by means of contact switching (not operational) due to switching of excitation current. From the above, it can be concluded that on a machine of the type SBSH250MNA32, a direct current electric drive is used according to the TP-D system (the engine is made in the G-D system). The use of a static power converter provides a wide range of control, the ability to form high-quality static and dynamic characteristics of the drive, due to its low inertia, higher efficiency, smaller dimensions and weight, and the rational layout of equipment in the machine room.

Technical data of DC motor DPV52.

Power, kW 60

Voltage, V 305

Current, A 220

Speed, rpm: nominal 1230

maximum 2200

Maximum moment at touching, N • m 1130

Maximum torque, N • m 932

The use of DC motors DPV52 on drilling machines is due to a number of their advantages (advantages):

Economical speed control within wide limits. It is possible to control the speed of the engines very smoothly, within wide limits and with completely minor losses in the adjusting apparatus.

Big start-up moment even at reduced mains voltage.

High overload capacity. Engines can develop a maximum moment many times higher than the nominal. However, the practical limitation of the maximum moment is caused by the deterioration of switching and sparking on the collector, in connection with which the engines develop an overload moment. M max. = 2 • Mn. However, it should be noted that large overloads do not cause engines to stop.

More reliable operation of automatic control equipment. practice has shown that most automatic control devices (contactors, relays) made on direct current work more reliably in operating conditions.

Despite the listed advantages of DC motors (DPV52), they have a number of drawbacks:

Lower reliability of electric motors. The DC motor (DPV52) is structurally complex. The presence of a manifold, brushes and associated sparking, especially when switching is deteriorating, creates large operational complications, requiring continuous skilled supervision and frequent repairs.

High cost of DC motors (DPV52). The complex design, the presence of a collector leads to a higher cost of engines.

Losses in the extra stage of power conversion. the need to use a thyristor rectifier (TEZ 160/460P unit) to convert AC to DC causes, in addition to the corresponding capital costs, constant energy losses in the thyristor rectifier. The value of these losses is about 10% of the total amount of energy to be converted.

Necessity due to use of thyristor converter of high engineering and technical training of maintenance personnel. Insufficient qualification of rig drivers does not allow quick and high-quality repair and replacement of failed converter elements.

The large overall dimensions and high weight of the electric motor complicate the installation and repair work.

The use of electric energy on the movable part of the machine (drill head) reduces the level of safety of work.

All these disadvantages lead to the idea of ​ ​ using not electric electricity, but some other more convenient in operation, simpler in design, type of energy. In this work, an attempt was made to replace the rotation electric drive system with a hydraulic drive system. To date, hydraulic drive is widely used in mining machines in underground open works. The use of a hydraulic drive allows you to create progressive machine designs, reduce their overall dimensions, increase durability, and expand the capabilities of control automation. The hydraulic drive provides the possibility of creating multi-drive systems, implementing high power in limited dimensions, high starting moments with reliable overload protection, accurate control of movements and speeds of mechanisms, autonomous power supply and high reliability. the use of hydraulic drive in drilling machines largely determines the safety of workers, which is one of the main criteria determining the possibility of introducing hydraulic drive systems.

1.4 Description and analysis of rotation hydraulic drive operation

1.4.1 Description of operation of rotator hydraulic drive.

In this diploma project, an attempt was made to replace the rotation electric drive system with a hydraulic drive system. Which in turn allows you to decommission the DPV52 electric motor, a thyristor converter and replace them with a high-torque hydraulic motor and a hydraulic drive system to it. In this diploma project, the existing hydraulic circuit does not change, a new hydraulic circuit independent of the existing one is added to it. In the free spaces in the engine room, instead of a thyristor converter, a new oil station designed for hydraulic drive of rotation is installed. As a result of studying the structural features of the machine, it is possible to conclude the possibility of using a high-torque rotary hydraulic motor and a pump with volumetric feed control, which in turn, if necessary, will be able to ensure the operation of other mechanisms (movement of the machine). Sheet (3) shows the hydraulic diagram of the designed drive. On the drill head there is a high-torque hydraulic motor of the rotator, which in turn controls the rotation of the drill stand. Fluid enters the hydraulic motor through hydraulic distributors P1 and P2, which are controlled by pilots. To protect the system from overloads, KP1 safety valve is installed; further, the system includes pressure gauges and a track damper for regulating the valve. Working fluid is supplied by H1 pump with volumetric control of supply from oil station. Hydraulic distributors are controlled from independent hydraulic system by pump H2, to which liquid is supplied from the proposed oil station. The control system is similar to the existing one. By examining the proposed hydraulic circuit, attention can be paid to its structural simplicity. But the practical observations made make it possible to conclude that it is necessary to simplify hydraulic systems. The use of the rotary drive of the present invention has a number of significant advantages. But before listing these advantages, it is necessary to say that the machines of the drilling section of the Muruntau mine work exclusively due to the professionalism of the drilling machine crews and the abilities of electromechanics. It is known from practice that the use of the calendar fund of time in the drilling site does not exceed 45%, and this largely depends on working conditions, convenient operation and prompt repair work. To date, the remuneration of rig drivers is real, and the equipment used has completely developed its limit. In this regard, crews are forced to reduce the time of emergency repairs in every way, this is carried out by simplifying the design and its systems, making them more repairable. In this regard, the proposed hydraulic system has some necessary advantages:

The absence of a gearbox and an electric motor greatly reduces and facilitates the design of the drill bit. Another repair unit is excluded - a reduction gear. All this facilitates repair and installation work.

The simplicity of the hydraulic drive system allows you to very quickly find a malfunction and eliminate it by the machine crew, and not by special specialists. Combining supply and rotation systems is not rational and only complicates both systems .

It has been established from practice that a large amount of time during drilling is spent on auxiliary operations, assembly and disassembly of the drilling stand. When screwing from the support assembly of the rod, a so-called "jerk" is required, which allows you to "pull" the thread and begin disassembly or assembly. The use of a high-torque hydraulic motor allows the machine crew to adjust the "jerk" itself. Vibrations during drilling and shaking during distillation must be taken into account. It is during these works that the adjustment of the "jerk" is upset and requires a new adjustment. In the case of using an electric drive, the intervention of special specialists is necessary. And it takes time. The use of a hydraulic motor simplifies the task of adjusting the "jerk."

The developed spinner drive offers two systems for controlling rotation modes: a) Manual, controlling the speed of rotation of the system by the driver; b) automatic control. The presence of two control systems is a feature and advantage of this drive. In practice, manual regulation is most often used, this is due to the mining and geological features of the deposit: the voids encountered, "frostbite," and great watering. But despite this, automatic control is promising.

Using a hydraulic drive allows you to maximize the safety of repair work on the mast.

The design of the machine and the hydraulic equipment used on it allows us to use this hydraulic drive system today without changing the main design of the machine.

Conclusions under Section:

In connection with the above data, the proposed hydraulic system has a number of advantages: the absence of a reduction gear and an electric motor thoroughly reduces and facilitates the design of the drill head. Excluded another repair unit - reduction gear. All this facilitates repair and installation work; the simplicity of the hydraulic drive system allows you to find a malfunction very quickly and transfer it by the machine crew, and not by special specialists; use of hydraulic drive allows to protect repair works on the mast as much as possible; the design of the machine and the hydraulic equipment used on it allows us to use this hydraulic drive system without changing the main design of the machine.

Based on the above, we propose to replace the motor drive system with a hydraulic drive system. Which allows you to decommission the DPV52 electric motor, thyristor converter and replace them with a high-torque hydraulic motor and a hydraulic drive system to it.