2-75
2. FUNCTIONS
FUNDAMENTAL FUNCTIONS
The pilot valve is a valve that controls the spool stroke, direction, etc of a main control valve. This
function is carried out by providing the spring at one end of the main control valve spool and apply-
ing the output pressure (secondary pressure) of the pilot valve to the other end.
For this function to be carried out satisfactorily, the pilot valve is composed of the following ele-
ments.
Inlet port (P) where oil is supplied from hydraulic pump.
Output ports (1, 2, 3 & 4) to apply pressure supplied from inlet port to ends of control valve spools.
Tank port (T) necessary to control the above output pressure.
Spool to connect output port to inlet port or tank port.
Mechanical means to control output pressure, including springs that work on the above spools.
FUNCTIONS OF MAJOR SECTIONS
Item numbers are based on the type L1.
The functions of the spool (3) are to receive the supply oil pressure from the hydraulic pump at its
port P, and to change over oil paths to determine whether the pressure oil of port P is led to output
ports 1, 2, 3 & 4 or the output port pressure oil to tank port T.
The spring (5) works on this spool to determine the output pressure.
The change the deflection of this spring, the push rod (9) is inserted and can slide in the plug (8).
For the purpose of changing the displacement of the push rod through the swash plate (16) and
adjusting nut (17) are provided the handle assy (20) that can be tilted in any direction around the
fulcrum of the universal joint (15) center.
The spring (7) works on the case (1) and spring seat (6) and tries to return the push rod (9) to the
zero-displacement position irrespective of the output pressure, securing its resetting to the center
position.
This also has the effect of a reaction spring to give appropriate control feeling to the operator.
1)
(1)
(2)
(3)
(4)
(5)
2)
Содержание HX430L
Страница 11: ...SECTION 1 GENERAL Group 1 Safety Hints 1 1 Group 2 Specifications 1 10 ...
Страница 161: ...4 6 MEMORANDUM HYUNDAI HEAVY INDUSTRIES CO LTD CONSTRUCTION EQUIPMENT DIV ...
Страница 205: ...4 50 No of pin Receptacle connector female Plug connector male 14 1 7 6 14 MG610406 KET SDL CONNECTOR 13 ...
Страница 528: ...8 88 Assemble relief valve assy 45 using torque wrench ÂTightening torque 26Ü2 6 kgfÂm 188Ü18 8 lbfÂft 31 43098TM95 ...
Страница 548: ...8 108 Remove lock nut 22 and then boot 23 14 36078RL14 2507ARL10 ...
Страница 559: ...8 119 14 15 3 Install cover 3 to body 1 and tighten bolts 14 Torque 10 12 5 kgf m 72 3 90 4 lbf ft 7 21078DA10 ...
Страница 589: ...8 149 1 STRUCTURE GROUP 11 WORK EQUIPMENT B SECTION C SECTION B SECTION A C C A B A 21078DA 44 ...