Balanced valve
Technical field
The present invention relates to a kind of hydraulic valve, a kind of hydraulically balanced valve that load stabilization can be kept to transfer.
Background technology
In the plant equipment such as the engineering machinery in modern times, building machinery, widely apply the hydraulic circuit that hoists, at concrete pump
In the exhibition arm of car and receipts arm system, commonly used balanced valve carries out hydraulic locking, to ensure that jib can at an arbitrary position may be used
By stopping.Wherein, balanced valve is the crucial Hydraulic Elements of load control system and hydraulic pressure load bearing system, the performance of balanced valve
Quality directly affects the running quality of main frame.And along with the increasing of concrete mixer job requirements difficulty, close to balanced valve
Feng Xing, self-locking performance, stationarity and polyfunctional requirement are more and more higher, and the power density of balanced valve self is the most increasingly
Greatly.With the continuous refreshing of operation height, the operating pressure of pumping vehicle arm rack system the most constantly rises.In this context, as
What improves boom system of concrete pump truck safety work performance and becomes research focus.
Common a kind of load applying balanced valve that Figure 10 show in the boom system of concrete mixer controls liquid
Pressure system.Its operation principle is: when reversal valve 3 ' is switched to load decline working position, the A mouth of reversal valve 3 ' is fuel-displaced,
Fluid enters the rod chamber Y of arm support oil cylinder, and part fluid enters the liquid controling cavity (piston of balanced valve through Px mouth and damping hole 1 '
Chamber) Pil, thus open balanced valve 2 ', the fluid of rodless cavity W is through C mouth and the V mouth of balanced valve 2 ' and reversal valve 3
B mouth oil sump tank T, then weight G declines;When reversal valve 3 is switched to load rising working position, B mouth is fuel-displaced, fluid
(agent structure of balanced valve generally comprises overflow valve in parallel and check valve to check valve in balanced valve 2 ', such as Fig. 4 institute
Show) enter oil cylinder rodless cavity W, the fluid of rod chamber Y rises through the A oil sump tank T, weight G of reversal valve 3 '.Commutation
When valve 3 ' does not switches, balanced valve 2 ' then cuts out, and seals up the fluid of C mouth and oil cylinder rodless cavity W, keeps weight G to exist
Desired position.There is multiple deficiency and defect in the hydraulic system in Fig. 4.Such as when being transferred to fast operating shelves, main oil
Hydraulic oil on road can quickly be increased with flow by the pressure of Px mouth, can be to the routine of balanced valve when balanced valve 2 ' is opened
Pilot control valve portion build-up of pressure impacts, and this impact may cause balanced valve to be opened suddenly, thus causes equipment to work not
Stable.In addition the control pressure limit of the balanced valve in Fig. 4 is narrow, and pressure and flowed fluctuation are big, and balanced valve opening process is micro-
Control and poor stability.This control pressure oscillation of balanced valve can cause the aperture of balanced valve 2 ' to produce with controlling flowed fluctuation
Change so that the piston position in arm support oil cylinder is difficult to be maintained on exact position.Therefore, very long jib it is arranged on
Easily there is the situation of a kind of instability in balanced valve on oil cylinder, causes the uncontrollability of equipment and makes equipment be operated in not
Under the state of safety.
The patent of invention of as entitled in Authorization Notice No. CN103104565B " balanced valve " discloses a kind of balanced valve.
But there is multiple deficiency and defect in this balanced valve.
1, in this invention, the pilot valve of balanced valve is a steel ball, in the little opening of balanced valve controls, needs the most accurate
Pilot pressure controls to realize the slowly varying to avoid the unexpected opening impact of balanced valve of flow.This is at general hydraulic pressure system
System is difficult to carry out.
2, the unlatching of balanced valve main valve plug is by load pressure, controls what pressure together decided on, the therefore change of load pressure
Main valve plug opening can be caused to change, and then cause changes in flow rate, cause main frame to shake.
3, pilot control level only has the pressure reducing circuit of 2 damping compositions, controls pressure at X mouth and produces owing to load changes big
Fluctuation when, it is impossible to well play cushioning effect, balanced valve valve core opening can be caused to change, cause hydraulic cylinder to tremble
Dynamic, this, on the long-armed implement such as high-altitude operation vehicle or concrete mixer, can cause the shake that main frame is violent, sternly
Ghost image rings job safety and homework precision.The pressure reducing circuit of pilot control level composition, some oil is directly to flow back to fuel tank
, this is in Mass flow system, and this oil return does not also have great impact, but in small flow system or by accumulator
The pilot handle of composition controls in loop, and it is the biggest that this part flows back to the flow loss of fuel tank, seriously limits this
Bright application.
4, valve pocket is monolithic construction, the processing of plug-in opening axiality is bad and installation moment of torsion is excessive when, can cause valve
Set deformation, causes balanced valve spool and controls stuck piston, reducing the reliability used.
Summary of the invention
The technical problem to be solved is to provide a kind of simple and reasonable, energy for above-mentioned prior art present situation
Reach stability contorting balance valve core aperture, not by load disturbance, the balanced valve of the bigger installation moment of torsion of permission.
The present invention solves the technical scheme that above-mentioned technical problem used: a kind of balanced valve, it is characterised in that: include tool
There is the valve body of spool chamber, valve body have the first hydraulic fluid port, the second hydraulic fluid port communicated with each other, valve body also has control port,
First hydraulic fluid port and the second hydraulic fluid port are positioned on body wall, and control port is then positioned at valve body leading section;Balance valve pocket, is arranged on
In the spool chamber of valve body, being provided with sealing ring between balance valve pocket periphery and spool chamber inwall, balanced valve puts and has connection the
Two hydraulic fluid ports and the import controlling chamber of balance valve pocket, in the front portion controlling chamber of balance valve pocket has annular, omoplate forms first
Valve port, first cross-sectional area, second cross-sectional area more than the first valve port controlling chamber of balance valve pocket;It is arranged on balanced valve
In set and can the balance valve core of sliding to axial, there is inside balance valve core ladder hole, balance valve core will balance valve pocket
The interior chamber that controls is separated into independent ante-chamber and back cavity two parts, and the second hydraulic fluid port is by the 4th damping in balance sleeve side wall
Hole connects with described back cavity, and the first valve port is stretched in the front end of balance valve core, the rear end of balance valve core and the inner chamber balancing valve pocket
Wall coordinates, and is connected by first conical surface between rear end and the front end of balance valve core, and this first conical surface is in order to block the first valve port;
Before balance valve core under shifting state, first conical surface and the contact of the first valve port, block the first hydraulic fluid port by the first valve port and second
Hydraulic fluid port connect, after balance valve core under shifting state, first conical surface leaves the first valve port, the first hydraulic fluid port by the first valve port with
Second hydraulic fluid port connection;In being arranged on the ladder hole of balance valve core and can sliding pilot valve to axial, pilot valve by
First spring holds holding reach trend, and pilot valve periphery has second conical surface that the small-bore portion with ladder hole coordinates,
Second conical surface is in order to block the small-bore portion of ladder hole, and the front end of pilot valve is positioned at the small-bore portion of ladder hole,
The rear end of pilot valve is positioned at the heavy caliber portion of ladder hole, is provided with to connect back cavity and rank in the rear end of pilot valve
3rd damping hole in the small-bore portion of ladder through hole, the front end periphery wall of described pilot valve has by rear to front flow area
The throttling channel that joint becomes larger;Under pilot valve reach state, second conical surface contacts with the small-bore portion of ladder hole,
Block back cavity via behind the 3rd damping hole and the small-bore portion of ladder hole with the connecting of the first hydraulic fluid port, move after pilot valve
Under state, back cavity connects with the first hydraulic fluid port via behind the 3rd damping hole, throttling channel and the small-bore portion of ladder hole successively;
Pilot control part, in order to make the pressure oil promotion pilot valve by control port move.
As improvement, the periphery, front end of above-mentioned balance valve core has to make the second hydraulic fluid port via the first valve port and the first hydraulic fluid port
The linking runner communicated.So when moving after balance valve core, the second hydraulic fluid port is made to communicate via linking runner and the first hydraulic fluid port, control
Make the flow velocity by the first valve port, it is ensured that work more steady.
For convenience of installing the first spring, being provided with the first spring base in above-mentioned back cavity, described first spring holds at first guide valve core
Rear end and the first spring base between.
Improving further, above-mentioned valve body forms by valve casing and by buckle structure floating connection at the adapter sleeve of valve casing rear end.
Valve body is made to form floating connecting structure, by buckle structure by valve casing and adapter sleeve floating connection, so in big installation
Moment of torsion or plug-in opening working axiality bad in the case of, the deformation of adapter sleeve will not be transferred to balance valve pocket, pilot valve
Core and following control piston, improve the reliability of balanced valve work.
3rd damping hole is for the benefit of set, in the rear end of above-mentioned pilot valve, is provided with to connect the little of back cavity and ladder hole
Second interface channel in aperture portion, the second interface channel female thread connects the 3rd damping block, and described 3rd damping hole is arranged
On the 3rd damping block.
Further improving, above-mentioned pilot control part includes the plunger shaft being located at valve inner rear end, and the front end of valve body is solid
Surely having the end cap blocking plunger shaft, have that connection is extraneous and the liquid outlet channel of plunger shaft in end cap, liquid outlet channel is by the
Two valve ports connect with plunger shaft, and described control port is arranged on end cap;First damping hole, is arranged in control port,
First damping hole connects extraneous and described plunger shaft;Nonreturn valve core, be located in liquid outlet channel and can liquid outlet channel relatively axial
Sliding, nonreturn valve core is held to keep blocking the trend of the second valve port by the second spring;It is located in plunger shaft and can be relative
The control piston of plunger shaft axial slip, controls to be provided with sealing ring between head and the inner hole wall of plunger shaft of piston and seals,
Plunger shaft is divided into rod chamber and rodless cavity two parts by the head controlling piston, is provided with to connect rod chamber in controlling piston
With the second damping hole of rodless cavity, the bar portion controlling piston passes the roof of rod chamber in order to promote described pilot valve, control
It is provided with sealing ring between bar portion and the roof inner hole wall of rod chamber of piston processed to seal, to block the spool of rod chamber and valve body
Chamber connects;3rd spring, is located in rod chamber and acts on and control the head of piston and make control piston keep towards end cap direction
The trend moved axially.
The advantage of aforementioned pilot control part is:
1), when the oil pressure px entering pilot-actuated valve from control port flies up, fluid is first entered by the first damping hole
In the rodless cavity of plunger shaft, in rodless cavity, the rising of pressure p1 promotes control piston to move to right;When entering guide from control port
The oil pressure px of control valve raises suddenly, and controlling moving to right of piston must discharge the fluid in rod chamber via the second damping hole
In rodless cavity, control piston and could continue to move to right, because of the existence of the second damping hole, when control piston moves to right in rod chamber
Pressure p 2 more than pressure p1 in rodless cavity, the pressure p 2 in rod chamber plays to stop and controls moving to right of piston, it is achieved that
Buffering;Only persistently rise when control pressure p x, control piston and could continue to move to right, serve controlling pressure oscillation
Filter action.In like manner, when the oil pressure px entering pilot-actuated valve from control port declines when, the pressure in rod chamber
In p2 and rodless cavity, pressure p1 declines (p1=p2 during poised state) simultaneously, the decline of pressure p2 in rod chamber, reduces
The resistance to the right that in rodless cavity, pressure p1 overcomes, plays the effect that dash-control piston moves to left.
2), again because need not the biggest buffering when that balanced valve being to cut out, by nonreturn valve core and the cooperation of the second spring,
Pressure p1 can be controlled in rodless cavity and control pressure p x reaching certain pressure reduction when, pressure p1 pressure in rodless cavity
Quickly opened by nonreturn valve core, via being expelled directly out pressure release after liquid outlet channel, it is not necessary to via the first damping hole, finally real
The quick closedown of existing balanced valve.The advantage of aforementioned pilot control part is:
For the benefit of arranging the first damping hole, the control port female thread of above-mentioned end cap connects the first damping block, and described first
Damping hole is arranged on the first damping block.
Second damping hole is for the benefit of set, in above-mentioned control piston, is communicated with the second interface channel of rod chamber and rodless cavity,
Second interface channel female thread connects has the second damping block, described second damping hole to be arranged on the second damping block.
For the benefit of assembling nonreturn valve core, be provided with the second spring base in the liquid outlet channel of above-mentioned end cap, described second spring holds
Between the second spring base and nonreturn valve core.
Improving further, above-mentioned end cap has the threaded post portion inserting and being threaded in plunger shaft, threaded
Having on the rear end face in post portion to controlling the annular wall that piston direction extends, annular wall is in order to the head contact with control piston.
Because lobe stretches in plunger shaft, therefore the length controlling piston can be done short, it is ensured that the afterbody controlling piston can stretch into
In heavy caliber portion, cost-effective, as there is no threaded post portion, then to ensure that the afterbody controlling piston stretches out plunger shaft
Can enter in heavy caliber portion, even if additionally the setting of annular wall guarantees that controlling piston crown contacts with the annular wall of end cap, also
Ensure that rodless cavity has certain space.
Compared with prior art, it is an advantage of the current invention that:
1, the throttling channel become larger by rear to front flow area joint is had on the front end periphery wall of pilot valve, to realize stream
Amount gradual change, so makees in fine motion or opens moment, and flow is moderate change, does not results in unexpected opening impact;
2, the open amount of balance valve core is controlled by pilot valve open amount, when pilot valve opens certain distance, the
The fluid of two hydraulic fluid port B through the 4th damping hole arrive back cavity, then via the 3rd damping hole, pilot valve throttling channel after flow into
First hydraulic fluid port A, the so pressure p 3 in pressure p B pressure and the back cavity of the second hydraulic fluid port have certain pressure differential, and second
Pressure p 3 in the pressure p B > back cavity of hydraulic fluid port, pressure p B of the second hydraulic fluid port acts on balance valve core and is formed by A1 and A2
Annulus area A12 on, the pressure p 3 in back cavity acts in balance valve core in the first cross-sectional area A 1, the most in the ban
When guide valve core opens certain distance, pB*A12 > pB*A1, balance valve core is made a concerted effort to move right;But balance valve core one
Moving right so that pilot valve opening reduces again (throttling channel effect), p3 rises again, until pb*A34=Pb*A3.First
The 3rd damping hole on guide valve core, has pressure compensation, it is ensured that balance valve flow is steady in the range of certain pressure
Fixed.So being based on this servo-actuated principle, the opening of balance valve core is not affected by load pressure, only by pilot valve
The quantity of motion of core determines, so flowed fluctuation will not be caused because of load change, produces vibration.
3, valve body is floating connection form, will not be because of installation moment of torsion is excessive or valve opening machining accuracy causes spool card not
Extremely, improve reliability.
Accompanying drawing explanation
Fig. 1 is the structure sectional view of the embodiment of the present invention;
Fig. 2 is the sectional view balancing valve pocket in the embodiment of the present invention;
Fig. 3 is the front view of balance valve core in the embodiment of the present invention;
Fig. 4 is the side view of balance valve core in the embodiment of the present invention;
Fig. 5 is the front view of pilot valve in the embodiment of the present invention;
Fig. 6 is the side view of pilot valve in the embodiment of the present invention;
Fig. 7 is the structure sectional view of pilot control part in the embodiment of the present invention;
Fig. 8 is the principle schematic of pilot control part in the embodiment of the present invention;
Fig. 9 is the application principle schematic diagram of the embodiment of the present invention;
Figure 10 is that the load of the common application balanced valve being currently used in the boom system of concrete mixer controls hydraulic pressure system
System.
Detailed description of the invention
Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail.
As shown in Fig. 1~9, for a preferred embodiment of the present invention.
A kind of balanced valve, including
There is the valve body 1 of spool chamber, valve body 1 has the first hydraulic fluid port A, the second hydraulic fluid port B communicated with each other, valve body 1
On also have control port X, the first hydraulic fluid port A and the second hydraulic fluid port B and be positioned on body wall, control port X is then positioned at valve
Body 1 leading section.Valve body 1 is by valve casing 12 and by buckle structure 13 floating connection adapter sleeve 14 in valve casing 12 rear end
Composition.
Balance valve pocket 2, is arranged in the spool chamber of valve body 1, is provided with sealing between balance valve pocket 2 periphery and spool chamber inwall
Circle, balance valve pocket 2 has connection the second hydraulic fluid port B and the import 21 controlling chamber of balance valve pocket 2, balance valve pocket 2
In the front portion in control chamber has annular, omoplate 22 forms the first valve port 4a, first cross-sectional area controlling chamber of balance valve pocket 2
The A1 the second cross-sectional area A 2 more than the first valve port 4a.
In being arranged on balance valve pocket 2 and can the balance valve core 3 of sliding to axial, inside balance valve core 3, there is ladder hole,
The chamber that controls in balance valve pocket 2 is separated into independent ante-chamber 5a and back cavity 5b two parts, the second hydraulic fluid port B by balance valve core 3
Being connected with back cavity 5b by the 4th damping hole 7d on balance valve pocket 2 sidewall, the front end 31 of balance valve core 3 stretches into first
Valve port 4a, the rear end 32 of balance valve core 3 coordinates with the internal chamber wall of balance valve pocket 2, the rear end 32 of balance valve core 3 and front
Being connected by first conical surface 33 between end 31, this first conical surface 33 is in order to block the first valve port 4a.Before balance valve core 3
31 peripheries are held to have the linking runner 311 making the second hydraulic fluid port B communicate via the first valve port 4a and the first hydraulic fluid port A.
Before balance valve core 3 under shifting state, first conical surface 33 contacts with the first valve port 4a, blocks the first hydraulic fluid port A and passes through
First valve port 4a and the second hydraulic fluid port B connection, after balance valve core 3 under shifting state, described first conical surface 33 leaves first
Valve port 4a, the first hydraulic fluid port A are connected by the first valve port 4a and the second hydraulic fluid port B.
In being arranged on the ladder hole of balance valve core 3 and can sliding pilot valve to axial 8, pilot valve 8 is by the first bullet
Spring 10a holds holding reach trend, is provided with the first spring base 11a, the first spring 10a and holds at pilot valve in back cavity 5b
Between rear end and the first spring base 11a of core.Pilot valve 8 periphery has what the small-bore portion 34 with ladder hole coordinated
Second conical surface 81, second conical surface 81 is in order to block the small-bore portion 34 of ladder hole, and the front end of pilot valve 8 is positioned at rank
In the small-bore portion 34 of ladder through hole, the rear end of pilot valve 8 is positioned at the heavy caliber portion 35 of ladder hole, pilot valve 8
Rear end in be provided with to connect the 3rd damping hole 7c in the small-bore portion 34 of back cavity 5b and ladder hole, described pilot valve
Having on the front end periphery wall of core 8 and saved, by rear to front flow area, the throttling channel 82 become larger, throttling channel 82 is triangular in shape
Shape.
Before pilot valve 8 under shifting state, second conical surface 81 contacts with the small-bore portion 34 of ladder hole, blocks back cavity
5b via behind the 3rd damping hole 7c and the small-bore portion 34 of ladder hole with the connecting, in pilot valve 8 of the first hydraulic fluid port A
Under rear shifting state, back cavity 5b successively via behind the small-bore portion 34 of the 3rd damping hole 7c, throttling channel 82 and ladder hole with
First hydraulic fluid port A connection.It is provided with to connect the small-bore portion 34 of back cavity 5b and ladder hole in the rear end of pilot valve 8
The second interface channel 83, second interface channel 83 female thread connect have the 3rd damping block 73, described 4th damping hole 7c
It is arranged on the 3rd damping block 73.
Pilot control part, in order to make the pressure oil promotion pilot valve 8 by control port X move.
Pilot control part includes
Be located at the plunger shaft 15 of valve body 1 Internal back end, valve body 1 be fixedly arranged at the front end with the end cap 6 blocking plunger shaft 15,
Having the liquid outlet channel 61 connecting extraneous and described plunger shaft 15 in end cap 6, liquid outlet channel 61 is by the second valve port 4b
Connecting with plunger shaft 15, control port X is arranged on end cap 6.
First damping hole 7a, is arranged in control port X, the first damping hole 7a connection external world and plunger shaft 15.End cap
The control port X female thread of 6 connects has the first damping block 71, the first damping hole 7a to be arranged on the first damping block 71.
Nonreturn valve core 16, in being located at described liquid outlet channel 61 and can liquid outlet channel 61 axial slip, this nonreturn valve core relatively
16 are held to keep blocking the trend of the second valve port 4b by the second spring 10b;It is provided with in the liquid outlet channel 61 of end cap 6
Second spring base 11b, described second spring 10b hold between the second spring base 11b and nonreturn valve core 16.
In being located at plunger shaft 15 and can the control piston 9 of opposing pistons chamber 15 axial slip, the head 91 of control piston 9
And being provided with sealing ring between the inner hole wall of plunger shaft 15 to seal, plunger shaft 15 is divided into by the head 92 of control piston 9 bar
Chamber 151 and rodless cavity 152 two parts, control to be provided with in piston 9 to connect the of rod chamber 151 and rodless cavity 152
Two damping hole 7b, the bar portion 92 controlling piston 9 passes the roof of rod chamber 151 in order to promote described pilot valve 8, control
It is provided with sealing ring between bar portion 92 and the roof inner hole wall of rod chamber 151 of piston 9 processed to seal, to block rod chamber 151
Connect with the spool chamber of valve body 1;End cap 6 has the threaded post portion 63 inserting and being threaded in plunger shaft 15,
Have on the rear end face in threaded post portion 63 to control piston 9 direction extend annular wall 62, annular wall 62 in order to
The head 91 controlling piston contacts.The second connection being communicated with rod chamber 151 and rodless cavity 152 in controlling piston 9 is logical
Road 93, the second interface channel 93 female thread connects has the second damping block 72, described second damping hole 7b to be arranged on the second resistance
On Buddhist nun's block 72.
3rd spring 10c, in being located at rod chamber 151 and act on and control the head 92 of piston 9 and make control piston 9 keep
The trend moved axially towards end cap 6 direction.
The operation principle of this balanced valve and process are divided into rising, stop, declining 3 processes, as shown in Figure 9.
Uphill process, the pressure oil of reversal valve arrives the pressure oil of the first hydraulic fluid port A, the first hydraulic fluid port A of balanced valve and promotes flat
Weighing apparatus spool 12 is opened (at this moment pilot valve 8 is closed mode), and the first oil flows into the second hydraulic fluid port B through A and arrives hydraulic cylinder
Rodless cavity, promotes hydraulic cylinder up.
Decline process, the pressure oil of control port X promotes control piston 15 to move to right, makes pilot valve 8 result from certain
Displacement, hydraulic cylinder is slowly declined by resting state;Control port X pressure continues to increase, and pilot valve 8 opening continues to increase
Greatly, hydraulic cylinder speed continues to increase;When pilot valve 8 displacement continues to increase to certain phase at control port X pressure,
Balance valve core 3 is opened, and the open amount of balance valve core 3 is controlled, when pilot valve 8 by pilot valve 8 open amount
Open certain distance, the fluid of the second hydraulic fluid port B through the 4th damping hole 7d arrive back cavity 5b, then via the 3rd damping hole 7c,
The first hydraulic fluid port A is flowed into, so in pressure p B pressure and the pressure in back cavity of the second hydraulic fluid port after the throttling channel 82 of pilot valve
Power p3 has certain pressure differential, the pressure p 3 in the pressure p B > back cavity of the second hydraulic fluid port, the pressure p B effect of the second hydraulic fluid port
On the annulus area A12 that balance valve core is formed by A1 and A2, the pressure p 3 in back cavity acts in balance valve core
In one cross-sectional area A 1, so when pilot valve opens certain distance, pB*A12 > pB*A1, balance valve core is closed
Power moves right;But balance valve core 3 one moves right so that pilot valve 8 opening reduces again (throttling channel 82 acts on),
P3 rises again, until pb*A34=Pb*A3.The 3rd damping hole 7c in pilot valve, has in the range of certain pressure
Pressure compensation, it is ensured that balance valve flow is stable.Because arranging of throttling channel 82 realizes flow gradual change, so micro-
Action or unlatching moment, flow is moderate change, does not results in unexpected opening impact.By control port X pressure controllable system
The opening of balance valve core 3, thus control the speed speed that oil cylinder declines.So it is based on this servo-actuated principle, balance
The opening of spool is not affected by load pressure, is only determined by the quantity of motion of pilot valve, so will not become because of load
Change and cause flowed fluctuation, produce vibration.
Stopped process, control port x pressure reduces, and pilot valve 8 reduces displacement, pilot valve 8 and balance valve core 3
Between formed throttling channel 82 area reduce, balance main valve plug 3 after end pressure increase, balance valve core 3 moves forward;Control oil
Mouth x pressure reduces to 0, and the first spring 10a pushes away before pilot valve 8, and second conical surface 71 is in order to block the little of ladder hole
Aperture portion 34, such balance valve core 3 is under the effect of the second hydraulic fluid port B pressure, and the realization that also travels forward is closed.
Operation principle and the process of this pilot-actuated valve are as follows:
1, when the pilot valve of balanced valve reaches balanced steady state, the oil pressure of pilot-actuated valve is entered from control port X
The pressure p 2 in pressure p 1=rod chamber 151 in px=rodless cavity 152, pilot valve 8 opening in balanced valve is stable,
Control piston 5 position to fix.
2, when the oil pressure px entering pilot-actuated valve from control port X flies up, fluid is first by the first damping hole 7a
Entering in the rodless cavity 151 of plunger shaft, in rodless cavity 151, the rising of pressure p1 promotes control piston 9 to move to right;When from control
Liquefaction mouth 62 enters the oil pressure px of pilot-actuated valve and raises suddenly, and controlling moving to right of piston 9 must be by rod chamber 152
Fluid be discharged in rodless cavity 151 via the second damping hole 7b, control piston 9 could continue to move to right, because of second damp
The existence of hole 7b, the pressure p 2 controlled when piston 9 moves to right in rod chamber 152, more than pressure p1 in rodless cavity 151, has
Pressure p 2 in bar chamber 152 plays to stop and controls moving to right of piston 9, it is achieved that buffering;Only hold when control pressure p x
Continuous rising, controls piston 9 and could continue to move to right, serve the filter action controlling pressure oscillation.In like manner, when from control
The when that liquefaction mouth X entering the oil pressure px decline of pilot-actuated valve, the pressure p 2 in rod chamber 152 and rodless cavity 151
Interior pressure p1 declines (p1=p2 during poised state) simultaneously, and in rod chamber 152, the decline of pressure p2, reduces rodless cavity
The resistance to the right that in 151, pressure p1 overcomes, plays the effect that dash-control piston 9 moves to left.
3, again because need not the biggest buffering when that balanced valve being to cut out, by nonreturn valve core 16 and the second spring 10b
Cooperation, pressure p1 can be controlled in rodless cavity 151 and control pressure p x reaching certain pressure reduction when, rodless cavity
In 151, pressure p1 pressure is quickly opened by nonreturn valve core 16, is expelled directly out pressure release via after liquid outlet channel 61, it is not necessary to
Via the first damping hole 7a, finally realize the quick closedown of balanced valve.
Although the preferred embodiments of the present invention described in detail above, it is to be clearly understood that for this area
For technical staff, the present invention can have various modifications and variations.All made within the spirit and principles in the present invention appoint
What amendment, equivalent, improvement etc., should be included within the scope of the present invention.