GB 25974.2-2010Powered support for coal mine -- Part 2: Specification for power set legs and rams (English PDF)

4.1 General requirements

4.1.1 No individual tolerance

No part patterned metal machining tolerances Note should meet the following requirements.

a) No injection dimensional tolerance limit deviations metal cutting pattern parts shall comply with GB/T 1804-2000m stage, no means with relations should be consistent with the provisions of GB/T 1804-2000c level;

b) a metal cutting pattern parts without individual tolerance limit of the angle deviation should comply with GB/T 1804-2000c stage;

c) a metal pattern non-cutting parts Note geometric tolerance limit deviation should meet the requirements GB/T 1184-1996K stage.

4.1.2 Pressure Weld

To withstand the liquid pressure of the weld should be able to withstand 200% of the rated working pressure of the hydraulic cylinder, the leakage test should 5min.

4.1.3 Forging

Steel castings shall comply with GB/T 11352 of.

Forgings shall comply with GB/T 12361 of.

4.1.4 Other elements

Hydraulic helical springs shall comply JB/T 3338.1 is.

Common threads shall comply with GB/T 197-2003 6,7 stage (6 external threads, internal threads 7) requirements.

Rod coating quality in the absence of specific requirements should be consistent with the provisions of Appendix A.

O-ring and groove dimensions should be consistent with GB/T 3452.1, GB/T 3452.3 requirements.

4.1.5 Lifting point

Cylinder is provided with suitable lifting points, the set of lifting points should be able to withstand 4 times the lifting force of the weight without damaging.

4.1.6 Valves and safety devices

And a support pillar jack should be fitted with safety devices to prevent the pressure exceeds the allowable value, the safety valve and means for fixing the charged shall mean not occur External action.

4.1.7 Working solution

Hydraulic cylinder fluid should meet the requirements of the MT76.

4.1.8 Welding

Welding operations comply with the requirements and quality (all parts) of the GB/T 12467.

4.1.9 Calculated allowable stress and static forces

Parts allowable stress and static calculation see Appendix B.

4.2 Assembly quality requirements

4.2.1 Assembly and appearance

Assembly and appearance quality should meet the following requirements.

a) prior to assembly, all parts of the respective surfaces of the burrs, chips, oil, etc. to be cleaned;

b) when assembled, the mating surface should not damage the part, all the threads should be coated thread antirust grease; should be carefully checked whether or cylinder seal old of, undercut, defects such as creasing, and strict attention to the presence or absence of seal extrusion and tear in the cylinder grooves or the like, if in the above Phenomenon, should be replaced immediately;

c) a hydraulic cylinder assembled, it should be reduced to a minimum state, and shall forward all, with a plastic plug seals the liquid return port;

d) after assembly (except the outer surface of the outer surface of the cylinder rod) should be sprayed or painted design requirements antirust primers and topcoats. Paint shall have Uniform, with a solid, there should be no peeling off phenomenon.

4.2.2 Cleanliness

After passing the test cylinder to be removed for cleaning, after washing impurities should not exceed Table 1, the value listed in Table 2 or Table 3.

Table 1 Single telescopic (including mechanical extension section) impurity content table column

Bore/mm column length/mm impurities/mg 100 the maximum length <=1000 30 1000 1000 <=1000 the shortest length of the test piece 1000 500 After 4.5.12.2 cylinder blast, brittle failure should not occur.

4.6 Material Properties

4.6.1 Steel

4.6.1.1 General performance

When the material stress reaches the calculated allowable stress of 90%, the tensile strength of the steel used for the cylinder is not less than 1.08 times the electrode yield 0.2% residual deformation limit or limits.

The elongation at break of the steel used delta5 not less than 10%.

4.6.1.2 Welded steel parts

Steel according to GB/T 6394-2002 grain size measured level not lower than 6; at -20 °C notch impact energy which shall not be less to 27J.

4.6.1.3 Non-welded steel parts

Non-welded steel cylinder with a predetermined cylinder 4.6.1.1 and 4.6.1.2 should meet.

When other non-welded steel parts at 20 °C notch impact energy of not less than 25J.

4.6.2 Light metal

The outer surface of the gas used in mines there is danger in the hydraulic cylinder, the GB should not be used in Chapter 8 of the light metal 3836.1-2000

--- or a light metal alloy comprising a coating and plating.

4.6.3 Other materials

Other parts of the cylinder material should meet the requirements of 4.6.1.1; non-metallic material should meet GB 3836.1-2000 Chapter 7 Requirements.

5.1 Test conditions

5.1.1 Working solution

Working fluid using emulsified oil or concentrate with a mass ratio of 5.95 by neutral soft high water formulated hydraulic fluid under MT76.

5.1.2 Pressure fluid temperature

During the test the temperature control fluid (10 ~ 50) °C, the working fluid using 40µm filter accuracy, and should be provided with the magnetic filter Device.

5.1.3 Level measurement accuracy and measurement system errors

Using grade C measurement accuracy, the measurement error of the system allows to comply with Table 5.

Table 5 allows the systematic errors of the measurement system

Measurements Level A Class B C Pressure error (gauge pressure >=0.2MPa) /% ± 0.5 ± 1.5 ± 2.5 Flow error /% ± 0.5 ± 1.5 ± 2.5 Temperature error/°C ± 0.5 ± 1.0 ± 2.0

5.2 General requirements

5.2.1 Pressure Weld

The hydraulic pressure of cylinder weld after welding of all, with the tooling cylinder top tight sealed ends, the cylinder bore pressure to 200% of rated voltage Force, pressure 5min. This test allows the hydraulic cylinder assembly.

5.2.2 Lifting point

Load lifting points vertically stretched 4-fold by a tensile weight lifting. The test also allows the disposable test mode by, for example, a Comparison may be performed on a specimen thereof.

5.3 Assembly and appearance

5.3.1 Assembly quality and appearance

Assembly quality and appearance and use common gage special measuring instrument under daylight or normal light inspected.

5.3.2 Cleanliness

Removing the cylinder after passing the test cleaning solution is collected after cleaning accuracy equivalent to 40µm filters, the resulting network Drying the article by weighing, the mass of the impurity mass.

5.4 The main components when the valve before the end of the test column, the column extending to the bottom valve is opened to supply hydraulic pressure to the end of the valve continuously open, fully extended live column, the rod chamber into the liquid column, the column reduced to a minimum. 3 cycles, by tactile inspection and heard; other conventional methods.

5.5 Plating

Conventional methods.

5.6 Performance Test

5.6.1 Sealability

The test shall be loaded on the fixed valve, a safety device, the seal and the cylinder hydraulic pressure in the joint and the extension rod.

Seal test (rear) locking pressure chamber when the hydraulic cylinder is loaded, continuous measurement of the pressure chamber and the pressure in the stroke 11min, the recording of the hydraulic cylinder Stroke or pressure changes over time, and expressed by a line in FIG. 1min taken before and after 5min before the test if performed 3min 2min.

NOTE. the various sealing pressure is the pressure value when the loading situation.

5.6.2 No-load stroke

Cylinder load, the moving speed is not greater than 200mm/min operating conditions, the full reciprocating stroke 3 times.

5.6.3 The minimum start-up pressure Column backpressure no-load condition, respectively, of the piston chamber and the rod chamber is gradually raised to full stroke Movable column, recording levels cylinder upper chamber Pressure chamber and start.

Column Column live fully retracted, holding the cylinder supply hydraulic pressure to the rod chamber, the rod chamber vat gradually boost the cylinder so that motion, which records the cylinder when the guide sleeve portion by vat, vat starting pressure piston chamber.

Jacks and load supporting jacks no back pressure conditions, respectively, the piston chamber and the rod chamber is gradually raised to the full stroke of the piston rod Moving the recording starting pressure piston chamber and the piston rod chamber.

5.6.4 Rod chamber sealing performance

Column as to minimize the height of the rod chamber and 2MPa plus 1.1 times the liquid supply pressure, the blocking seal cavity regulator 5min.

Jack as to minimize the height of the rod chamber and 2MPa plus 1.1 times the liquid supply pressure, the blocking seal cavity regulator 5min.

5.6.5 Let pressure performance

5.6.5.1 Performance Center presser

5.6.5.1.1 Compression presser

Jack post or all of the outer support extension, the safety valve opening pressure is adjusted to the rated working pressure, the test under the following conditions.

a) with (10 ± 2) mm/min speed, twice the stroke of 100mm so that pressure test;

b) with the (2 ± 1) mm/min speed, twice the stroke of 20mm so that the test pressure;

c) Multistage column at a level converter (10 ± 2) mm/min speed, twice let 100mm stroke pressure test.

5.6.5.1.2 Stretch presser

The stretched support jack presser Yaoan compression method so that a tensile and compression testing.

5.6.5.1.3 Speed presser

When the support jack in work have a higher velocity, at a higher speed so that pressure test.

Records Center during the presser force and pressure changes over time.

5.6.5.2 Eccentric presser

By the amount of eccentricity of FIG. 1 or FIG. 2, using the same test method 5.6.5.1, only the eccentric load, so that the pressure recording during the eccentric force and pressure changes over time.

Note. Only the support column and jack were let pressure test.

FIG eccentrically loaded column 1

FIG 2 is loaded eccentrically supporting jacks

5.6.6 Performance Center Overload

5.6.6.1 1.5 times the rated load compression Inner or outer loading test load.

a) an outer loading step.

1) with 0.8 times the nominal worki...