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Cherendichenko Yulia

Faculty engineering mechanics and engineering

Department mining machines

Speciality ''Mining equipment (Computer designing the mechanical mining equipment)''

Justification of parameters of subsystem of pendant of executive branches of cleansing combines with the turning block of cutting

Scientific adviser: prof., d.t.s. Kondrakhin Vitaly

1. The urgency of the problem. Analysis of research and scientific innovation. Purpose of the work.
2. The calculation of basic parameters SSCB combine with RCU.
3. Designing VPD.
   • The general device jacks suspension damper .
   • Development of design stem.
   • The choice of disc springs.
4. Construction of the amplitude-frequency characteristics (AFC) for the SSCB of cases of hydraulic jacks without the VPD and with VPD.
5. References.
6. List of sources.

The urgency of the problem

Design and parameters of modern shearers should provide reliable and high produtivity work of all complex of equipment cleaning and security staff. The excavation machinery determine the produtivity of all complex. Heavy mining and geological mining machine operating conditions necessitate a substantial to increase their technical level and quality, and above all reliability and produtivity. That is, improvements shearers old generation. Shearers new generation, in contrast to the former have several distinctive features. One of the most important features is the implementation of the executive bodies of the drive subsystem (EB) and subsystem suspension and move EB-based rotary cutting units (RCU). The advantages of such a structural arrangement solutions are:

• exclusion of unreliable bevel gear;
• implementation of the shorter of the kinematic chain, including in some cases with the use of compact planetary gear [1,2].

In connection with the use RCU for improvement of research methods and calculating the parameters of the suspension system and control of the executive body (SSCB). For example, dynamic loads, which are formed in the suspension system EB during the passage of geological disturbances, reduce the reliability of hydraulic jacks lifting the executive body of nodes Swivel housing and turning the main gear with one another and with the hydraulic jacks. The life of these elements harvester can be upgraded by installing a damping device for reducing the dynamic loads. In this context, rationale and development of methods of investigation and calculation of parameters of the suspension system and regulation of executive authority in its design with features that ensure efficient operation in terms of increased loads on the breakage face is an actual scientific and practical problems having a branch value.

Analysis of research and scientific innovation

Many authors devote their labour for decision of delema, which coherents which research and calculation of parameters SSEB. They develop analytical methods and to conduct experimental studies. But for the shearers new generation of these techniques require further. In this work, we propose technique of the choice of parameters and calculate the maximum loads SSCB to combine with the RCU (for example, combine the KDK-400). The analysis of the relationship dispersion of loads on hydraulic jack when the stiffness of the suspension, which allows to solve the problem of research, design and optimization parameters of the SSCB.

Purpose of the work

The aim is to improve the technique for choosing optimal parameters and calculate the SSCB combines with the RCU, providing increase operational efficiency shearers SSCB.

The chosen design scheme (pic. 1) calculates the main parameters SSCB combine. Geometric parameters of the system are chosen according to [2].

Picture 1. Constructive scheme SSCB combine KDK-400.

Based on the maximum capacity of the destroyed layer and the necessary quantities of penetration ispolnitelnogo body into the soil layer in its lower position, we determine the smallest and the largest distance between mounting jacks:

Pressure P, MPa set pressure relief valve hydraulic SSCB is determined by the required effort vedichinoy jacks needed for the regulation of EB. We consider two cases:
- regulation of EB when it is dry running;
- regulation of EB, destructive backspace.

The maximum static load on the hydraulic jack in the regulation of the executive body of running dry. The calculation is done for the poor performance and advanced body.

The maximum static load on the hydraulic jack in the regulation of the executive body, the destructive backspace.

Maximum static load as calculated Fp, H attains its maximum absolute value of the load.

If Fp> 0, then hydraulic jack works in tension and the design pressure in its rod space is defined as

The area of the piston jacks

The value obtained Ppn (Ppw) rounded side and take as the pressure setting relief valve hydraulic control of the executive bodies.

The calculation of the maximum hydraulic jack SSCB. The calculation is made for the most advanced suspension system of a loaded body.

The calculation of the maximum hydraulic jack SSCB. The calculation is made for the most advanced suspension system of a loaded body. The maximum force on the hydraulic jack deystvuyaschaya SSCB:

Maximum load on the hydraulic jack SSCB monotonic roll-over motor.

For further calculations made most of the above values of maximum force acting on a hydraulic jack SSCB

The value obtained for the maximum pressure is rounded side and take as the pressure settings of safety valves to protect the cavity of the hydraulic jacks overweight in those time periods when these cavities are locked attachment bracket [3].

This methodology tried out the example of shearer KDK-400 to establish baseline data. The calculation results can be obtained from the author's master's work.

The vibroprotection device (VPD) which is built in hydraulic jacks. This device reduces vibration rotary gear with an executive body with influence on them of dynamic fluctuations. Hydraulic jack (pic. 1) consists of a housing 1, which contain a rod 2 with piston wich attaches here 3. Stem 2 is empty and it has a removable head stock 4. The braking element 5 sets in stock 2, it made in the form located in the boring rods 2 stepped cylindrical of plunger 6, which forms the piston 7 and 8 piston chamber. They connected to throttle openings 9 and 10 with the piston rod 11 and 12 cavities of the hydraulic jacks, and it has an elastic element 13. This is a package of spring washers, wich has nonlinear characteristics. Belleville springs installed through the sleeve 14 on shank of the plunger 6 and recorded in the axial direction. Through distance ring 15 wich rest on the head of the rod 4. The piston cavity 7 is connects wich cavity 11 in the throttle washer 16. The piston chamber 8 connects with cavity 12 throughthrottle hole 17.

The spool element 5 overcomes the resistance of the elastic element 13 and moves to the left when increasing pressure in the piston cavity. The liquid flows into the cavity 11 from the cavity 7 through the throttle hole 9 . So then the piston 3 moves to the right on a distance, wich proportional to the volume of fluid wich has flowed into the cavity 11 [4].

Picture 2. Hydraulic suspension damper.

Rod diameter is determined as follows: the ratio of the plane piston hydraulic jacks to the plane of the rod should be against the respective piston planes VPD:

The ratio of the planes and piston rod hydraulic jacks:

Piston rod diameter:

Determines the thickness of the piston: Нn=32 mm

When choosing the springs should be understood that they should work on the entire range of loads on the jacks. The required maximum load is determined by the pressure setting relief valve that protects the cavity of hydraulic jacks.

The maximum force on the rod VPD determined from the formula:

To improve the effectiveness of VPD advisable to perform an elastic element in the form of serial connection of three packages of springs.

Spring constant is determined by the dependence [5]:

Graph of the load on the packages of springs on the deformation of the spring has a piecewise-linear character and is presented оn piс. 3.

Picture 3 – Graph of the elastic characteristics of a package of springs (F - force, s - strain).

Principle of operation SSEB with VPD presented at the pic. 4.

Picture 4 – Principle of operation SSEB with VPD (1 - EB, 2 - SSCB, 3 - axis of rotation SSCB, 4 - a package of springs, 5 - hydraulic jack).

(Animation: volume - 112 KB; size - 585x397; number of frames - 7; number of cycles of repetition - 7)

In compiling the equations of motion mechanism SSCB accept the assumption that the loads acting on a linear plot. Then the equation of forced oscillations of the form [6]:

Dynamic amplification factor[7]:

From got data build amplitude-frequency characteristics (AFC) (pic. 5) for the cases of work of gidrodomkrata without VPD (curve 1) and with VPD (curves 2, 3, 4).

Picture 5. AFC SSCB for the cases of work of gidrodomkrata without VPD and with VPD to middle position EB.

Pic. 6 and 7 show for lower and upper positions EB.

Picture 6. AFC SSCB for the cases of work of gidrodomkrata without VPD and with VPD for lower position of EB.

Picture 7. AFC SSCB for the cases of work of gidrodomkrata without VPD and with VPD for upper position of EB.

It is seen that when we use of VPD the maximum frequency response curve reduces about 12.5% and its position shifts to the left, which corresponds to decrease the natural frequency of the system. It reduces the dynamic component loads on jacks SSCB. The variance of the load on the system is proportional to the area under the curve of a square frequency response in acting on random EB loads in the form of "white noise". VPD with parameters reduce the dispersion of the load on the hydraulic jack not less than 2,5 times(from pic. 3).

This labour proposes an improved technique for the analysis and the choice of force, kinematic and dynamic parameters and calculate the maximum loads SSCB of shearers with rotary cutting units.

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10. Scientific work NG Boiko. The dynamics driving the executive body of shearers and its characteristics for random perturbations [electronic resource]. - Mode of access: http://www.nbuv.gov/ ~ /Stat1.pdf
11. The scientific work of N. Sysoev, A. Kozhevnikov. Algorithm and technical implementation mechatronic management performance parameters shearer [Electronic resource]. - Access mode: http://www.nbuv.gov.ua/ ~ /Stgm_27.pdf

Note

In writing this abstract master's work was not completed. The final completion - December 1, 2011. Full text of the work and materials on the subject can be obtained from the author or scientific adviser after this date.

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