CN210290305U - Load holding valve and engineering machinery with same - Google Patents
Load holding valve and engineering machinery with same Download PDFInfo
- Publication number
- CN210290305U CN210290305U CN201920508276.9U CN201920508276U CN210290305U CN 210290305 U CN210290305 U CN 210290305U CN 201920508276 U CN201920508276 U CN 201920508276U CN 210290305 U CN210290305 U CN 210290305U
- Authority
- CN
- China
- Prior art keywords
- valve
- cavity
- chamber
- axial direction
- core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Safety Valves (AREA)
Abstract
The utility model provides a load keeps valve and engineering machine tool who has it, load keeps the valve to include: the valve comprises a valve body, a valve body and a valve core, wherein a first valve cavity with two through ends and a second valve cavity with one open end are defined in the valve body; the main valve core assembly is arranged in the first valve cavity along the axial direction of the first valve cavity, and a plurality of throttling holes, throttling grooves and conical surfaces are arranged on the main valve core assembly; the piston assembly is arranged in the first valve cavity along the axial direction of the first valve cavity and is positioned at one end of the main valve core assembly; the locking valve core assembly is arranged in the second valve cavity along the axial direction of the second valve cavity; the sealing elements are respectively sleeved on the main valve element assembly at intervals; a one-way throttle assembly located inside the PL chamber. Utility model real load keeps the valve can realize the zero leakage of meso position.
Description
Technical Field
The utility model relates to an engineering machine tool especially relates to a load keeps valve and engineering machine tool that has it.
Background
The large cavity of the boom cylinder and the small cavity of the bucket rod cylinder are connected by a hose and a control valve, and when the hose is suddenly broken, an actuating mechanism (a large arm and a small arm) can be instantly pricked, so that potential safety hazards are caused.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a load keeps valve should keep the valve to avoid after the hose breaks suddenly or lift by crane the heavy object in-process, movable arm and dipper drop.
The utility model also provides an engineering machine tool of having above-mentioned load and keeping the valve.
According to the utility model discloses a load keeps valve of first aspect embodiment includes: the valve comprises a valve body, a first valve cavity and a second valve cavity, wherein two ends of the first valve cavity are communicated with each other, one end of the second valve cavity is opened, an A cavity, a B cavity and a PL cavity are further defined in the valve body, the first valve cavity is communicated with the A cavity, and the second valve cavity is respectively communicated with the B cavity and the first valve cavity; the main valve core assembly is arranged in the first valve cavity along the axial direction of the first valve cavity, and a plurality of throttling holes, throttling grooves and conical surfaces are formed in the main valve core assembly; the piston assembly is arranged in the first valve cavity along the axial direction of the first valve cavity and is positioned at one end of the main valve core assembly; the locking valve core assembly is arranged in the second valve cavity along the axial direction of the second valve cavity; the sealing elements are sleeved on the main valve element assembly at intervals; a one-way throttle valve assembly disposed inside the PL chamber.
According to the utility model discloses load keeps valve through increasing a plurality of sealing members on main valve core to through conical surface, the relief valve cone case combined action on locking case, the main valve core, can realize the meso position zero leakage, avoid the hose to break suddenly the back or lift by crane the heavy object in-process, swing arm and dipper drop.
The load holding valve according to embodiments of the present invention may also have the following additional technical features:
according to the utility model discloses an embodiment, first valve pocket with second valve pocket parallel arrangement, the A chamber is established first valve pocket is kept away from one side of second valve pocket, the B chamber is established the second valve pocket is kept away from one side of first valve pocket, first valve pocket with the A chamber is through first oil circuit intercommunication, first valve pocket with the second valve pocket is through second oil circuit and third oil circuit intercommunication, the second valve pocket with the B chamber is through second oil circuit intercommunication.
According to an embodiment of the present invention, the main spool assembly includes: the first plug is arranged at one end of the first valve cavity along the axial direction of the first valve cavity, and one end of the first plug abuts against the piston assembly and closes one end of the first valve cavity; the spring seat is arranged at the other end of the first valve cavity along the axial direction of the first valve cavity; the main valve core is movably arranged in the first valve cavity along the axial direction of the first valve cavity, one end of the valve core is stopped against the piston assembly, the other end of the valve core is stopped against the spring seat, and a plurality of throttling holes, throttling grooves and conical surfaces are arranged on the main valve core; the first elastic piece is arranged on the spring seat along the axial direction of the first valve cavity, and one end of the first elastic piece abuts against the first valve core.
According to an embodiment of the invention, the load holding valve further comprises: the second plug is arranged at the other end of the first valve cavity and seals the other end of the first valve cavity, an opening is formed in one end, facing the first valve cavity, of the second plug, the spring seat is arranged in the opening, and at least one part of the main valve core extends into the opening.
According to an embodiment of the present invention, the main spool assembly further comprises: the first valve pocket is arranged in the first valve cavity along the axial direction of the first valve cavity and sleeved at one end of the main valve core, and a plurality of throttling holes are formed in the first valve pocket; and the second valve sleeve is arranged in the first valve cavity along the axial direction of the first valve cavity and sleeved at the other end of the main valve core.
According to an embodiment of the present invention, the sealing member includes: the first sealing element is sleeved on the main valve core and is positioned between one end of the first valve sleeve and the valve body; a second seal member received in an end of the first valve housing adjacent the first seal member; a third seal disposed about an end of the second sleeve adjacent the spring seat.
According to the utility model discloses an embodiment, the valve body still is equipped with and is located first valve pocket is kept away from one side of second valve pocket and with the fourth oil circuit of first valve pocket intercommunication, the exit end of fourth oil circuit is equipped with and seals the third end cap of fourth oil circuit.
According to the utility model discloses an embodiment, locking case subassembly includes: the fourth plug is arranged at the open end of the locking valve core along the axial direction of the locking valve core; the locking valve core is arranged in the locking valve core along the axial direction of the locking valve core, one end of the locking valve core abuts against the fourth plug, the other end of the locking valve core is used for communicating the first oil path and the second oil path, and a spring cavity is defined at one end, facing the fourth plug, of the locking valve core; and the second elastic piece is arranged in the spring cavity.
According to an embodiment of the invention, the load holding valve further comprises: the safety valve is arranged on one side of the valve body and communicated with the first valve cavity.
According to the utility model discloses an embodiment, still be equipped with in the valve body and be located first valve pocket is kept away from one side of second valve pocket and with the fifth oil circuit of first valve pocket intercommunication, be equipped with one-way throttle valve in the import PL intracavity of fifth oil circuit.
A construction machine according to an embodiment of the second aspect of the present invention includes the load holding valve according to the above-described embodiment.
Drawings
Fig. 1 is a schematic structural view of a load holding valve according to an embodiment of the present invention;
fig. 2 is yet another schematic structural view of a load holding valve according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the operation of a load holding valve according to an embodiment of the present invention.
Reference numerals:
a load holding valve 100;
a valve body 10;
main spool assembly 20; a main spool 21; a first plug 22; a spring seat 23; a first elastic member 24; a fifth plug 25; a first valve housing 26; a second valve housing 27; a first seal 28; a second seal 29;
a piston assembly 30; a third seal 31;
a latching spool assembly 40; a fourth plug 41; a lock-up spool 42; the second elastic member 43; a fourth seal 44; a fifth seal 45;
a second plug 50;
a third plug 60; a sixth seal 61;
a safety valve 70;
a one-way throttle valve assembly 80; a plug screw 81; a cone spool 82; a spring 83;
and a seventh plug 91.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The load holding valve 100 according to an embodiment of the present invention will be described first in detail with reference to the drawings.
As shown in fig. 1-3, a load holding valve 100 according to an embodiment of the present invention includes a valve body 10, a main poppet assembly 20, a piston assembly 30, a latched spool assembly 40, a one-way throttle assembly 80, and a plurality of seals.
Specifically, a first valve cavity with two through ends and a second valve cavity with one open end are defined in the valve body 10, a cavity A and a cavity B are further defined in the valve body 10, the first valve cavity is communicated with the cavity A, the second valve cavity is communicated with the cavity B and the first valve cavity respectively, the main valve element assembly 20 is arranged in the first valve cavity along the axial direction of the first valve cavity, a plurality of throttle holes, a throttle groove and a conical surface are arranged on the main valve element assembly 20, the piston assembly 30 is arranged in the first valve cavity along the axial direction of the first valve cavity and is located at one end of the main valve element assembly 20, the locking valve element assembly 40 is arranged in the second valve cavity along the axial direction of the second valve cavity, a plurality of sealing elements are respectively sleeved on the main valve element assembly 20 at intervals, and the one-
In other words, load-holding valve 100 is primarily comprised of a valve body 10, a main poppet assembly 20, a piston assembly 30, a latched poppet assembly 40, a plurality of seals, and a one-way throttle assembly. The piston assembly 30 and the main valve core 21 are respectively arranged in a first valve cavity, the locking valve core assembly 40 is arranged in a second valve cavity, and a piston acted by pilot pressure and a piston acted by overflow of an overflow valve are the same. The load holding valve 100 can keep the boom and the arm from falling after the hose connecting the boom cylinder large cavity and the arm cylinder small cavity is suddenly broken.
Therefore, according to the utility model discloses load holding valve 100 through increasing a plurality of sealing members on main valve core 21, can realize the meso position zero leakage, avoids behind the hose rupture suddenly or lifts by crane the heavy object in-process, and movable arm and dipper drop.
According to some specific embodiments of the utility model, first valve pocket and second valve pocket parallel arrangement, the A chamber is established in the one side that the second valve pocket was kept away from to first valve pocket, and the B chamber is established in the one side that first valve pocket was kept away from to the second valve pocket, and first valve pocket and A chamber are through first oil circuit intercommunication, and first valve pocket and second valve pocket pass through second oil circuit and third oil circuit intercommunication, and the second valve pocket passes through the second oil circuit intercommunication with the B chamber.
Main poppet assembly 20 optionally includes a first plug 22, a spring seat 23, a main poppet 21, and a first resilient member 24.
Specifically, the first plug 22 is arranged at one end of the first valve cavity in the axial direction of the first valve cavity, one end of the first plug 22 abuts against the piston assembly 30 and closes one end of the first valve cavity, the spring seat 23 is arranged at the other end of the first valve cavity in the axial direction of the first valve cavity, the main valve element 21 is movably arranged in the first valve cavity in the axial direction of the first valve cavity, one end of the valve element abuts against the piston assembly 30, the other end of the valve element abuts against the spring seat 23, a plurality of throttling holes are formed in the main valve element 21, and the first elastic element 24 is arranged on the spring seat 23 in the axial direction of the first valve cavity and one end of the first elastic element. It should be noted that a fifth plug 25 is further disposed between the piston assembly 30 and the main valve element 21 and on the main valve element.
In one embodiment of the present invention, the load holding valve 100 further comprises a second plug 50.
Specifically, the second plug 50 is disposed at the other end of the first valve chamber and closes the other end of the first valve chamber, an opening is formed at one end of the second plug 50 facing the first valve chamber, the spring seat 23 is disposed in the opening, and at least a portion of the main valve element 21 extends into the opening, so that the second plug 50 is simple in structure and convenient to install.
According to one embodiment of the present invention, main poppet assembly 20 further includes a first valve housing 26 and a second valve housing 27.
Specifically, the first valve sleeve 26 is disposed in the first valve cavity along the axial direction of the first valve cavity and sleeved at one end of the main valve element 21, the first valve sleeve 26 is provided with a plurality of throttling holes, the second valve sleeve 27 is disposed in the first valve cavity along the axial direction of the first valve cavity and sleeved at the other end of the main valve element 21, and the first valve and the second valve sleeve 27 are respectively matched with the main valve element 21.
Preferably, the seals include a first seal 28, a second seal 29 and a third seal 31.
Specifically, the first sealing element 28 is disposed on the main valve element 21 and located between the first valve sleeve 26 and the valve body 10, the second sealing element 29 is disposed on one end of the first valve sleeve 26 adjacent to the first sealing element 28, the third sealing element 31 is disposed on one end of the second valve sleeve 27 adjacent to the spring seat 23, the first plug 22 is further provided with a fifth sealing element 45 and a sixth sealing element 61, and the plurality of sealing elements are respectively formed into a sealing ring structure, so as to prevent the middle position of the load holding valve 100 from leaking.
According to the utility model discloses an embodiment, valve body 10 still is equipped with the fourth oil circuit that is located one side that second valve pocket was kept away from to first valve pocket and communicates with first valve pocket, and the exit end of fourth oil circuit is equipped with third end cap 91 that can seal the fourth oil circuit.
According to another embodiment of the present invention, the locking valve core assembly 40 includes a fourth plug 41, a locking valve core 42 and a second elastic member 43.
Specifically, the locking valve core assembly 40 is disposed in the second valve cavity to form a locking valve, the fourth plug 41 is disposed at an open end of the locking valve core 42 along an axial direction of the locking valve core 42, the locking valve core 42 is disposed in the locking valve core 42 along the axial direction of the locking valve core 42, one end of the locking valve core 42 abuts against the fourth plug 41, the other end of the locking valve core 42 is used for communicating the first oil path and the second oil path, a spring cavity is defined at one end of the locking valve core 42 facing the fourth plug 41, the second elastic member 43 is disposed in the spring cavity, and the fourth plug 41 is further provided with a fourth sealing member 44.
Preferably, the load maintaining valve 100 further includes a safety valve 70, the safety valve 70 is disposed at one side of the valve body 10 and is communicated with the first valve chamber, the structure is simple, when the safety valve reaches an overflow pressure, a small flow rate from the chamber B to the chamber a overflows, and a function of a one-way throttle valve at the PL port is increased, a sixth plug 91, a one-way valve cone 81 and a spring 82 are sequentially disposed at one end of the safety valve 70 connected with the first valve chamber from left to right, wherein the sixth plug 91 is a screw plug. It should be noted that the theoretical zero leakage is achieved by the combined action of the latching spool 42, the tapered surface on the main spool 21, the conical spool in the relief valve 70, and some seals.
In an embodiment of the present invention, a fifth oil path is further disposed in the valve body 10, the fifth oil path is located on a side of the first valve chamber away from the second valve chamber and is communicated with the first valve chamber, and a one-way throttle valve is disposed in an inlet PL chamber of the fifth oil path.
The operation of the load maintaining valve 100 according to an embodiment of the present invention will be described in detail below.
And (3) forward opening: the oil liquid enters the flow passage of the oil port A, pushes the locking valve core 42 away and enters the cavity B; and (3) middle position keeping: the cone valve core on the locking valve, the first sealing element 28, the conical surface on the main valve core 21, the second sealing element 29 and the safety valve 70 can ensure that the leakage quantity is 0 theoretically when the valve is in a middle position; and (3) reverse opening: PL pilot open and relief valve 70 overflow open.
PL pilot on: when pilot oil enters PL, the pilot oil pushes the piston assembly 30 through the one-way throttle valve, and further pushes the main valve element 21, so that oil in the cavity B enters the cavity A through the throttling hole in the main valve element 21; after the pilot pressure of effect increases, the stroke of main valve element 21 increases, and fluid in the spring chamber of lock valve passes through orifice on first valve barrel 26 and the orifice UNICOM in the main valve element 21, gets into A chamber, causes the lock valve to open, makes the spring intracavity fluid pressure in the lock valve step down, and the lock valve opens under the pressure differential effect.
In summary, according to the load holding valve 100 of the present invention, by adding a plurality of sealing members to the main valve element 21 and by the combined action of the locking valve element 42, the conical surface on the main valve element 21, and the safety valve 70, the neutral zero leakage can be realized, and the drop of the boom and the arm after the hose is suddenly broken or during the process of lifting the heavy object can be avoided.
According to the utility model discloses engineering machine tool includes the load according to above-mentioned embodiment and keeps valve 100, because according to the utility model discloses the load of above-mentioned embodiment keeps valve 100 to have above-mentioned technological effect, consequently, according to the utility model discloses engineering machine tool also has corresponding technological effect, can realize neutral zero leakage, avoids behind the hose rupture suddenly or lifts by crane the heavy object in-process, and swing arm and dipper drop.
The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.
Claims (11)
1. A load holding valve, comprising:
the valve comprises a valve body, a first valve cavity and a second valve cavity, wherein two ends of the first valve cavity are communicated with each other, one end of the second valve cavity is opened, an A cavity, a B cavity and a PL cavity are further defined in the valve body, the first valve cavity is communicated with the A cavity, and the second valve cavity is respectively communicated with the B cavity and the first valve cavity;
the main valve core assembly is arranged in the first valve cavity along the axial direction of the first valve cavity, and a plurality of throttling holes, throttling grooves and conical surfaces are formed in the main valve core assembly;
the piston assembly is arranged in the first valve cavity along the axial direction of the first valve cavity and is positioned at one end of the main valve core assembly;
the locking valve core assembly is arranged in the second valve cavity along the axial direction of the second valve cavity;
the sealing elements are sleeved on the main valve element assembly at intervals;
and the one-way throttle valve component is arranged inside the PL cavity and positioned on one side of the first valve cavity, which is far away from the second valve cavity.
2. The load holding valve according to claim 1, wherein the first valve chamber and the second valve chamber are arranged in parallel, the a chamber is provided on a side of the first valve chamber remote from the second valve chamber, the B chamber is provided on a side of the second valve chamber remote from the first valve chamber, the first valve chamber and the a chamber are communicated through a first oil passage, the first valve chamber and the second valve chamber are communicated through a second oil passage and a third oil passage, and the second valve chamber and the B chamber are communicated through a second oil passage.
3. The load holding valve of claim 2, wherein the main spool assembly comprises:
the first plug is arranged at one end of the first valve cavity along the axial direction of the first valve cavity, and one end of the first plug abuts against the piston assembly and closes one end of the first valve cavity;
the spring seat is arranged at the other end of the first valve cavity along the axial direction of the first valve cavity;
the main valve core is movably arranged in the first valve cavity along the axial direction of the first valve cavity, one end of the valve core is stopped against the piston assembly, the other end of the valve core is stopped against the spring seat, and a plurality of throttling holes, throttling grooves and conical surfaces are arranged on the main valve core;
the first elastic piece is arranged on the spring seat along the axial direction of the first valve cavity, and one end of the first elastic piece abuts against the first valve cavity.
4. The load holding valve of claim 3, further comprising:
the second plug is arranged at the other end of the first valve cavity and seals the other end of the first valve cavity, an opening is formed in one end, facing the first valve cavity, of the second plug, the spring seat is arranged in the opening, and at least one part of the main valve core extends into the opening.
5. The load holding valve of claim 3, wherein the main spool assembly further comprises:
the first valve pocket is arranged in the first valve cavity along the axial direction of the first valve cavity and sleeved at one end of the main valve core, and a plurality of throttling holes are formed in the first valve pocket;
and the second valve sleeve is arranged in the first valve cavity along the axial direction of the first valve cavity and sleeved at the other end of the main valve core.
6. The load holding valve of claim 5, wherein the seal comprises:
the first sealing element is sleeved on the main valve core and is positioned between one end of the first valve sleeve and the valve body;
the second sealing element is sleeved at one end, far away from the first sealing element, of the first valve sleeve;
a third seal disposed about an end of the second sleeve adjacent the spring seat.
7. The load holding valve according to claim 3, wherein the valve body is further provided with a fourth oil passage located on a side of the first valve chamber away from the second valve chamber and communicated with the first valve chamber, and an outlet end of the fourth oil passage is provided with a third plug capable of closing the fourth oil passage.
8. The load holding valve of claim 2, wherein the latching spool assembly comprises:
the fourth plug is arranged at the open end of the locking valve core along the axial direction of the locking valve core;
the locking valve core is arranged in the locking valve core along the axial direction of the locking valve core, one end of the locking valve core abuts against the fourth plug, the other end of the locking valve core is used for communicating the first oil path and the second oil path, and a spring cavity is defined at one end, facing the fourth plug, of the locking valve core;
and the second elastic piece is arranged in the spring cavity.
9. The load holding valve of claim 1, further comprising:
the safety valve is arranged on one side of the valve body and communicated with the first valve cavity.
10. The load holding valve according to claim 1, wherein the valve body is further provided with a fifth oil passage located on a side of the first valve chamber remote from the second valve chamber and communicating with the first valve chamber, and an outlet PL chamber of the fifth oil passage is provided with a one-way throttle valve.
11. A working machine, characterized by comprising a load holding valve according to any one of claims 1-10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920508276.9U CN210290305U (en) | 2019-04-16 | 2019-04-16 | Load holding valve and engineering machinery with same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920508276.9U CN210290305U (en) | 2019-04-16 | 2019-04-16 | Load holding valve and engineering machinery with same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210290305U true CN210290305U (en) | 2020-04-10 |
Family
ID=70067994
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920508276.9U Active CN210290305U (en) | 2019-04-16 | 2019-04-16 | Load holding valve and engineering machinery with same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210290305U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112879365A (en) * | 2021-01-19 | 2021-06-01 | 龙工（上海）精工液压有限公司 | Load holding valve for excavator |
-
2019
- 2019-04-16 CN CN201920508276.9U patent/CN210290305U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112879365A (en) * | 2021-01-19 | 2021-06-01 | 龙工（上海）精工液压有限公司 | Load holding valve for excavator |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101821827B1 (en) | Proportional poppet valve with integral check valve | |
| US4624445A (en) | Lockout valve | |
| US20100300552A1 (en) | Hydraulic valve device | |
| US9874232B2 (en) | Fluid pressure control apparatus | |
| CN109826838B (en) | Load holding valve | |
| GB2516341A (en) | Flow responsive latch for holding a spool valve in an open position | |
| US20110132476A1 (en) | Hydraulic valve device | |
| JP4776366B2 (en) | Actuator control device | |
| CN103899596B (en) | A kind of hydraulic lock of band guide's check valve | |
| CN105822618A (en) | Lifting valve plate of electric-hydraulic proportional multi-way valve of forklift | |
| CN210290305U (en) | Load holding valve and engineering machinery with same | |
| US3933167A (en) | Pilot operated check valve | |
| CN108266431B (en) | Two-stage pressure bidirectional overflow valve | |
| CN107504005B (en) | Forced oil supplementing multi-way valve driven to judge | |
| US10619753B2 (en) | Pilot type switching valve | |
| KR100490479B1 (en) | Holding valve apparatus for excavator and its oil pressure control method | |
| EP1961973B1 (en) | Actuator control device | |
| KR101509259B1 (en) | Holding Valve of hydraulic device | |
| CN210013877U (en) | Load holding valve and hydraulic system | |
| CN204878101U (en) | Take off -load valve core to let out formula hydraulic pressure lock valve device in | |
| CN209414292U (en) | A kind of excavator novel load holding valve | |
| CN104653537B (en) | Lockable reversing valve | |
| CN210686480U (en) | Flow control type hoist balance valve | |
| CN109185498B (en) | Proportional balance valve | |
| CN109882467B (en) | Hydraulic cylinder safety valve and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |