Substantiation of the structure of the electronic system of vibrodiagnostics of a mining combine
Content
- Introduction
- 1. The purpose and objectives of the study, the planned results
- 2. Object Analysis and Problem Statement
- 3. Technical task for the development of a microprocessor system for vibrodiagnostics of a mining combine
- Conclusion
- References
Introduction
Coal takes the first place in the world among minerals in terms of reserves and production. Every year in the world more than 4.5 billion tons of coal and brown coal are mined. According to forecasts in the new century, its share in the world energy balance will grow.
Achieving the pace is possible only with the reliability of technology, which allows you to work without accidents. As experience of operation of roadheaders shows, downtime of machines often causes breakdown of reducers, bearings of reducers and electric motors fail. This caused possible technological disruptions in the manufacture and operational rules for the use of machinery. Sometimes downtime due to significant reasons make up from 20 to 25% of the working time of combines. Therefore, the creation of adaptations that determine the occurrence of pre-emergency situations is a top priority.
One of the criteria for the possible deterioration of the technical condition of the drive, there is an increase in vibration mechanisms, which leads to the failure of machines. The technical state of the machine can be determined by analyzing the parameters characterizing its vibration. The creation of an adaptation of a level of vibration determined by the possibility of further exploitation of combines is an actual task.
This problem is being studied by scientists from the CIS countries and abroad. "Avtomatormash" developed an adaptation of automatic diagnostics of mining machines during start-up and adjustment works and repairing measurement and analysis of vibration for conveyors [ 3 ]. The Zion Scientific Research Institute proposes to solve this problem by a certain complex index of the spectral characteristics of the vibration signal [ 4 ].
The basis and theoretical prerequisites for solving this problem are. It is necessary to create a device that allows you to analyze vibration parameters, determine the technical state of the machine and the possibility of its further use.
1. The purpose and objectives of the study, the planned results
The purpose of the work is to create a microprocessor system for vibrodiagnostics of a mining combine that reliably operates under difficult operating conditions, which will allow controlling vibration and detect pre-emergency situations of the cutting drive, thereby improving the reliability and productivity of the combine.
Tasks, solved by the development:
- automation of the diagnostics process of the roadheader,
- reduction of costs for maintenance and repair due to the detection of defects in the early stages of their development, the forecasting of the technical condition of the cutting drive,
- increase in the quality of adjustment and regulation by providing information to repair personnel about the current values ??of the monitored parameters,
- increase the safety of the staff.
The received results - the microprocessor system of vibrodiagnostics of a drive of cutting of a road-moving combine is designed. Designed structural, circuit diagrams, printed circuit boards of this system, as well as software. Blocks of the system are implemented on a modern element base. [ 5 ]
2. Object Analysis and Problem Statement
The P-160 pusher is designated for horizontal and inclined, up to ± 10%, preparatory workings with cross-section from 9 to 33 m2 in drilling through rock, mixed and coal faces at rock hardness up to 100 MPa with one compression and abrasiveness up to 15 mg in The mines, dangerous on gas and a dust. Shape of workings out, with a flat ground.
The productivity and quality of the roadheaders mainly depends on the quality and ability to control the combine during its operation. The following factors have a significant effect on the effectiveness of combining selective action by combines: strong dust formation; impossibility to achieve stability in regulating the load of the executive body and to protect against overloading; unacceptable deviations in the direction of the conducted workings from the preset existing gross control methods, which lead to significant interruptions in the processing of the face for the production of a given section, and before the need to introduce corrections.
The existing control systems of tunneling combines enable the latter to operate in modes that affect the rapid wear of its individual components and, in general, the combine as a whole. To speed up the repair, very high qualification of the maintenance staff is required, which is not always possible for mine conditions. At this time, automation devices are created to ensure the diagnostics of the serviceability of the control station and the main parts of the tunneling machine. This is the ability to speed up troubleshooting, recognize pre-emergency and emergency situations. [ 6 ]
The diagnostics methods installed on such tunneling complexes do not provide diagnostics of the reasons for cutting. The reason for cutting the roadheader is a series connection of the electric motor and gearbox and as a diagnostic object is characterized by this specific feature, which is not always repaired directly in the mine conditions. To carry out or repair a replacement, they need to be delivered to the surface, which is a complex and time-consuming process. The actual task is the difference between pre-accident situations of the reducer and electric motor failures. One of the indicators is an increase in the level of vibration. Vibration sensors are used to measure vibration parameters. These sensors can be placed on the supporting couplings between the electric motor and the reducer. The quality of the installation of couplings and their technical condition, which is strengthened during operation, in many respects means the overall technical condition of the unit.
To diagnose the state of mechanical transmission, the most widely used method was vibrodiagnostics. This diagnostics is necessary for the roadheader, because it will be possible to establish the terms of bearing wear, which increase the productivity and quality of the combine's operation.
The microprocessor-based vibrodiagnostics system of the P-160 tunneling machine is designed to control the overall vibration of the cutting drive and to detect, as a result of diagnostics, such equipment defects: imbalance of the rotor mass, air gap in the bearings, incompatibility of the drive motor and the reducer of the executive body. The general structure of the MCS includes processing the signal from the vibration sensor, displaying information on diagnostics, switching off the motor at unacceptable levels of vibration and operating modes of the drive. [ 9 ]
Based on the diagnostic results obtained, it is possible to further identify the causes of the effects of defects in the equipment. For example: the causes of the imbalance in the equipment can be of different nature, as a result of many features of design and operation. They can be divided into several main groups:
- the defect in the manufacture of the rotor of its elements in the plant, in the repair enterprise, inadequate output control of the enterprise - the manufacture of equipment, shocks during transport, poor storage conditions,
- incorrect assembly of equipment during the initial or installation after the repair,
- presence on the rotor of worn out, broken, defective, missing, insufficiently fastened, etc. parts and assemblies,
- the result of the influence of the parameters of technological processes and features of operation of this equipment, which lead to uneven heating and curvature of the rotors.
Identification of emergency situations is the main indicator of the developing microprocessor system, which ensures the efficiency of the tunneling machine.
3. Technical task for the development of a microprocessor system for vibrodiagnostics of a mining combine
The P-160 forage harvester, for which this microprocessor system is designed, is designed for horizontal and inclined up to ± 10%, preparatory workings with cross-section from 9 to 33 m2, in digging through rock, mixed and coal faces with rock strength up to 100 MPa with one compression and abrasiveness up to 15 mg in mines dangerous for gas and dust. The shape of any workings, with a flat ground.
The object of diagnostics in the tunneling machine is the reducer of the actuator, the electric motor and the coupling. Technical characteristics of the objects of diagnosis:
-frequency range of vibration variation (without vibration of bearings) from 5 to 200 Hz [ 7 ]
-dimension range of the SKU Vibration speed in the linear frequency spectrum (from the technical state of "Normal" to "Accident") from 0.4 to 20 mm / s.
The microprocessor system consists of a vibration transducer block, a diagnostics block, an information processing unit and cable jumpers. Such a composition allows to have functionally complete nodes and to minimize cable connections. Each unit is located on a separate board with terminals.
The vibration transducer block is designed to convert the mechanical oscillations of the Przadz cutting into an electrical signal and includes a piezoelectric measuring Vibrosensor and a preamplifier.
The diagnostic module is intended for amplification, filtering and processing of output signals from a vibration transducer.
The information processing unit includes a microprocessor node and three LEDs. The unit is designed to process information coming from the diagnostic unit; implementation of diagnostic algorithms; formation of an array of information about the technical state of the facility; giving information to the display and transferring it to the controller of the electronic control system of the roadheader.
Cable jumpers are designed to connect the diagnostic unit with vibration transducers. A special vibration cable is used in the cable jumpers.
The microprocessor system of vibrodiagnostics of a roadheader must be placed in an explosion-proof housing with an electronic control system of the pass-through machine, each printed circuit board must still be in a separate plastic casing. Minimum dimensions of shells, not more than 300õ150õ250 mm.
The design of the product must meet the requirements of aesthetics, ergonomics and engineering psychology. The level of artistic and constructive solutions must correspond to the best modern domestic and foreign models.
When choosing brands and assortments of materials, it is necessary to be guided by the requirements of reducing the material consumption of the product and reducing the consumption of scarce materials. [ 1 ]
Conclusion
In the diploma project, a microprocessor system for vibrodiagnostics of the P-160 roadheader was designed. To do this, a review of the analogs, justification of the choice of the original vibration transducers was carried out. As generator shakers, generator piezoelectric accelerometers were chosen. Such methods for measuring the vibration of the drive of the cutting machine have been implemented: an estimation of the overall vibration of electric motors and a reducer in the SKU Vibro speed, measurement of vibration at informative frequencies, assessment of the technical condition of bearings by measuring shock pulses. A technical project for the design of the system was developed. The calculation of the nodes of the circuit is performed and the metrological characteristics of the system are estimated. An overview is given of various modern digital integrated circuits and microcontrollers. The developed design and software of the system. According to GOSTs all technical and design documentation is made. The projected system fully meets the requirements set forth in the technical task. Design can be considered complete. The system can be manufactured and used in production.
References
- Magazine "Coal of Ukraine" ¹1, 2004. - 80 s
- Magazine "Coal of Ukraine" ¹2, 2004. - 80 s
- Magazine "Coal of Ukraine" ¹3, 2004. - 80 s
- Journal of Modern Automation Technologies No. 7, 1999. - 80 p.
- Bauman E. Measurement of Forces by Electric Methods; Ed. I. I. Smyslov. - Moscow: Mir, 1978. - 430 p.
- Solovanov MN, Fridmak AE, Kudryashova Zh.F. Quality of measurements: Metrological reference book - L: Lenizdat 1987. - 290 p.
- Calculation of electronic circuits. Examples and tasks. Training. Allowance for Universities / G.I. Izuryova et al., M.Zh., 1987. - 332 p.
- Rudenko VS, Senko VI et al. Fundamentals of Industrial Electronics. - Ê .: Âèùà øêîëà, 1985.- 400 with.
- Gutnikov VS Integral Electronics in Measuring Devices. - 2nd ed., Pererab.i dop.-L .: Energoizdat. Leningrad. Otd-tion, 1988.-304 p.
- Yakubovsky SA, Barkanov NA ,. Kudryashov V.P. Analog and Digital Integrated Circuits: A Handbook / Ed. S.Yakubovsky. M .: Radio and Communication, 1985. p. - 336 s.
- Sources of power supply for radio electronic equipment. Directory. Under. Ed. G.S. Nyquist. - M. Radio and Communication, 1986.
- Semiconductor devices: thyristors. Directory. Under. Ed. N.N. Goryunova, 1983.
- Panfilov DI, Chepurin II, Mironov VN Electrical Engineering in Experiments and Exercises: Workshop on Electronics Workbench: Vol. 1.2. - Moscow: DODEK, 2000. 288 p.
- Kharinsky AA Basics of designing elements of radio equipment. - L .: Energy, - 1971. - 464 p.
- GOST 2.001-70. ESKD. Basic provisions.
- GOST 2.109-73. ESKD. Basic requirements for drawings.
- GOST 15.001-73. ESKD. Scheme of development and delivery of products in production.
- GOST 2.417-78. ESKD. Rules for the implementation of drawings of printed circuit boards
- Business plan of the investment project. Practical Manual / Pod. Ed. Ivannikova I.A. - Moscow: "Expert Bureau" - M., 1997. - 112 p.