Equilibrium valve
Technical field
The present invention relates to a kind of hydrovalve, relate in particular to the equilibrium valve that is applied in oil hydraulic circuit.
Background technique
In the machinery such as the engineering machinery in modern times, building machinery, widely applied the oil hydraulic circuit that hoists, wherein equilibrium valve is the crucial hydraulic element of controlling oil hydraulic motor work in hoisting circuit, the quality of equilibrium valve performance directly affects the performance of main frame.
Existing equilibrium valve is divided into two kinds of board-like equilibrium valve and cartridge balanced valves by Placement, in order to reduce installing space, improves system reliability in the crane telescopic oil cylinder, generally adopts cartridge balanced valve.The patent of invention that patent No. ZL01139273.8 name is called " a kind of equilibrium valve " provides a kind of equilibrium valve of plug-in type.It comprises main valve, pilot valve, above-mentioned each valve all comprises two chambeies that are positioned at the spool front and back, and wherein main valve comprises valve pocket, main valve plug, and described valve pocket is cylindrical tube, be provided with the first main hydraulic fluid port A and the second main hydraulic fluid port B on the outer side surface of valve pocket, pilot valve is positioned at main valve plug.This equilibrium valve is owing to can directly inserting the oil hydraulic cylinder head, a plurality of spring structures that adopt rigidity to differ due to its main spool spring, mix the skewed slot on main valve plug circular cone side, make control more accurate, sensitive, even in the situation that decompression, guide's spool in main valve plug can be closed rapidly the oil circuit between the second main hydraulic fluid port and the first main hydraulic fluid port, can prevent that load stall from descending, and plays the effect of a hydraulic lock.
But there is following shortcoming in this equilibrium valve:
1, this balancing valve structure is complicated, required precision is high, there is the requirement of coaxality just to have more than six places between each part, and the gap, place that is slidably matched of main valve plug and valve pocket, guide's spool and main valve plug is all minimum, the manufacturing process difficulty is large, during the actual use of product, spool easily blocks, thereby can affect the reliability of host work.
2, guide's spool (nonreturn valve core) of this equilibrium valve is located at main valve plug (balance valve core) inside, main valve plug wired seal request again and between valve pocket, also wired seal request between guide's spool and main valve plug.This just requires place, main valve plug circular cone side that very high hardness will be arranged, preventing the wearing and tearing of part, and main valve plug inner chamber and guide's spool cooperation place hardness relative hanging down again.This has just proposed very high request to heat treatment and the material of main valve plug, has increased processing cost.
3, because guide's spool of this equilibrium valve is located at main valve plug inside, in order to reduce flow resistance, certainly will will increase the size of guide's spool, the size of main valve plug and valve pocket also will become greatly in succession, makes the overall dimensions of equilibrium valve bigger than normal.And the diameter of oil hydraulic cylinder is certain, and the oversize words of equilibrium valve will make the machining allowance of the plug-in opening on oil hydraulic cylinder less than normal, cause certain difficulty to processing.
4, the damping link of this equilibrium valve inside is few, disturbs stability inferior poor in ambient conditions, easily produces shake.
Summary of the invention
Technical problem to be solved by this invention is: overcome the above-mentioned shortcoming of prior art, a kind of simple in structure, volume compact is provided, the reliable equilibrium valve of working stability.
The present invention addresses the above problem the technological scheme that adopts: a kind of equilibrium valve comprises being provided with the first hydraulic fluid port and the second hydraulic fluid port and the first chamber being set vertically and piston that the valve body of the tubular of the second chamber, the end cap that is sealedly connected on respectively valve body two ends and screw plug, spool, steel ball, valve seat and cover have the second spring; Described screw plug rear end is provided with the 3rd hydraulic fluid port, and described the 3rd oil port is provided with filter screen device, damping device, and described valve seat is located in valve body the first chamber, and between the first hydraulic fluid port, the second hydraulic fluid port; Described spool leading portion is slidably tied in end cap, the back segment of described spool is matched with in the through hole of valve seat, described spool is provided with the inner chamber that axially runs through, be provided with the first steel ball that matches with valve core cavity in described spool, and described valve core cavity is provided with for steel ball being carried out the boss of axial limiting, described valve core cavity is provided with the first spring that offsets with the first steel ball, and the other end of described the first spring is butted in end cap; Described piston cunning is assigned in the second chamber, and the stepped end of piston rod passes the locular wall between the first chamber and the second chamber and be slidably tied in the inner chamber of spool, and described piston rear end is provided with one-way throttling device.
Compared with prior art, the invention has the advantages that: this balancing valve structure is simple, volume compact, and between each part, coaxality is less, and the place that is slidably matched is less demanding, and manufacturing process is simple.This cartridge balanced valve only is provided with a spool, and some technologic problems that relate to when need not to consider main valve plug and guide's spool plug-in mounting have reduced processing cost.And the size of this equilibrium valve more easily guarantees, can be plugged in easily into the oil hydraulic cylinder head.
As improvement, described one-way throttling device is fixed in the ear end face of piston, and described one-way throttling device comprises the first damper and the second steel ball, and described the second steel ball is placed in the 3rd chamber of piston and matches with the valve port of the first damper.Add the damper that the screw plug rear end is provided with, this cartridge balanced valve has just comprised two damping links.The pressure that produces after two damping rings flow successively is pressure after decompression, can improve the balance Operating stability of valve like this, reduces vibrations.
Description of drawings
Fig. 1 is the structural representation of equilibrium valve of the present invention.
Fig. 2 is the structural representation of equilibrium valve of the present invention.(when load is risen)
Fig. 3 is the structural representation of equilibrium valve of the present invention.(when load descends)
Fig. 4 is the application hydraulic schematic diagram of equilibrium valve of the present invention.
Shown in Fig. 1-4: 1 end cap, 2 valve bodies, 3 first springs, 4 spring seats, 5 first steel balls, 6 spools, 6.1 boss, 7 valve seats, 8 piston rods, 9 second springs, 10 second steel balls, 11 pistons, 12 first dampers, 13 second dampers, 14 screw plugs, 15 filter screens.
A the first hydraulic fluid port, B the second hydraulic fluid port, X, the 3rd hydraulic fluid port.
G the first chamber, H the second chamber, I the 3rd chamber, J the 4th chamber.
A the first radial direction through hole, b the second radial direction through hole, c third through-hole, d the 4th radial direction through hole, e fifth hole, f the 6th through hole.
Embodiment
Below in conjunction with accompanying drawing, embodiments of the invention are further described.
As shown in Figure 1, a kind of equilibrium valve comprises being provided with the first hydraulic fluid port A and the second hydraulic fluid port B and the piston 11 that the valve body 2 of the tubular of the first chamber G and the second chamber H, the end cap 1 that is sealedly connected on respectively valve body 2 two ends and screw plug 14, spool 6, steel ball, valve seat 7 and cover have the second spring being set vertically; Described screw plug 14 rear ends are provided with the 3rd hydraulic fluid port X, and described the 3rd hydraulic fluid port X place is provided with filter screen 15, the second damper 13, and described valve seat 7 is located in valve body 2 first chamber G, and between the first hydraulic fluid port A, the second hydraulic fluid port B; Described spool 6 leading portions are slidably tied in end cap 1, the back segment of described spool 6 is matched with in the through hole of valve seat 7, described spool 6 is provided with the inner chamber that axially runs through, be provided with the first steel ball 5 that matches with spool 6 inner chambers in described spool 6, and described spool 6 inner chambers are provided with for steel ball being carried out the boss of axial limiting, described spool 6 inner chambers are provided with the first spring 3 that offsets with the first steel ball 5, and the other end of described the first spring 3 is butted in end cap 1; Described piston 11 is sliding to be assigned in the second chamber H, and the stepped end of piston rod 8 passes the locular wall between the first chamber G and the second chamber H and be slidably tied in the inner chamber of spool 6, and described piston 11 rear ends are provided with one-way throttling device.
Described one-way throttling device is fixed in the ear end face of piston 11, and described one-way throttling device comprises the first damper 12 and the second steel ball 10, and described the second steel ball 10 is placed in the 3rd chamber I of piston 11 and matches with the valve port of the first damper 12.
The periphery that described spool 6 back segments match with the through hole of valve seat 7 is conical surface, and the outer conical surface of described spool 6 and valve seat 7 linear sealings.
Described spool 6 middle parts are provided with the first radial direction through hole a that is communicated with the second hydraulic fluid port B and spool 6 inner chambers, and its rear end is provided with the second radial direction through hole b that is communicated with the first hydraulic fluid port A and spool 6 inner chambers.
The first chamber G of described valve body 2 and the locular wall between the second chamber H are provided with the third through-hole c that is communicated with two chambers.
Described piston 11 middle parts are provided with the 4th radial direction through hole d of the 3rd chamber I that is communicated with valve body 2 second chamber H and piston 11.
Fig. 4 is the application hydraulic schematic diagram of equilibrium valve of the present invention, the first hydraulic fluid port A of this equilibrium valve is connected with the hydraulic fluid port A1 of selector valve, the second hydraulic fluid port B is connected with hydraulic rod rodless cavity B1, the hydraulic fluid port B3 of selector valve is connected with rod chamber B2, the 3rd hydraulic fluid port X of oil hydraulic cylinder respectively, and the other two hydraulic fluid port P of selector valve and O be cut-in pressure oil sources and oil sump tank respectively.
Working principle of the present invention is as shown in Fig. 2,3:
1, when load is risen, selector valve is beaten in left position, hydraulic oil enters valve body 2 from the first hydraulic fluid port A, on the one hand hydraulic oil enters the second chamber H by the third through-hole c that the first chamber G and the locular wall between the second chamber H of valve body 2 is provided with, entered again the 3rd chamber I of piston by the 4th radial direction through hole d on piston 6, and the second steel ball 10 is withstood on the valve port of the first damper 12, block the passage that is entered the 4th chamber J by the 3rd chamber I.On the other hand, hydraulic oil acts on the impacting force that overcomes the first spring 3 on spool 6, and spool 6 is moved to left, and at this moment, hydraulic oil can flow to the second hydraulic fluid port B by the first hydraulic fluid port A, and enters the rodless cavity B1 of oil hydraulic cylinder, rises thereby promote load.
2, when load descends, selector valve is got to right position, hydraulic oil enters the 4th chamber J by the 3rd hydraulic fluid port X by the 6th through hole f on filter screen 15 and the second damper 13.At this moment, the fifth hole e of part hydraulic oil on the first damper 12 backs down the 3rd chamber I that the second steel ball 10 flows into piston 11, the 4th radial direction through hole d that is provided with by piston 11 middle parts again flows into the second chamber H, the third through-hole c that is provided with by the locular wall between valve body 2 first chamber G and the second chamber H again flows into the first hydraulic fluid port A, at this moment the pressure of the hydraulic oil of the first hydraulic fluid port A is the pressure that the hydraulic oil of the 3rd hydraulic fluid port X produces after two damper throttlings, be pressure after decompression in fact, can improve the balance Operating stability of valve like this.Other a part of hydraulic oil of the 4th chamber J acts on piston 11, and the active force pushing piston 11 that overcomes the second spring 9 moves to left, the active force that piston rod 8 external parts of piston 11 first push up the first steel ball 5 and overcome the first spring 3 backs down the first steel ball 5, at this moment, the hydraulic oil of the second hydraulic fluid port B flows into spool 6 inner chambers by the first radial direction through hole a at spool 6 middle parts, and flow into the first hydraulic fluid port A by the second radial direction through hole b of spool 6 rear ends, thereby make the load slow decreasing.Piston 11 continues to move to left, and piston rod 8 external parts of piston 11 push up on spool 6, and makes spool 6 break away from valve seat 7, and at this moment the hydraulic oil of the second hydraulic fluid port B flows into the first hydraulic fluid port A by the gap between spool 6 and valve body 2 again, thereby makes the load rate of descent accelerate.
3, when loadlock aloft the time, selector valve is beaten at meta, the 3rd hydraulic fluid port X takes back fuel tank, the path of cut-out pressure source and selector valve A1, spool 6 makes spool 6 reset under the pressure-acting of the first spring 3 and load generation, the outer conical surface of spool 6 back segments matches with valve seat 7 again, form linear sealing, cut off the path between the first hydraulic fluid port A and the second hydraulic fluid port B, with loadlock aloft.