CN110307143B - Variable servo valve, power servo valve and variable pump - Google Patents
Variable servo valve, power servo valve and variable pump Download PDFInfo
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- CN110307143B CN110307143B CN201910542058.1A CN201910542058A CN110307143B CN 110307143 B CN110307143 B CN 110307143B CN 201910542058 A CN201910542058 A CN 201910542058A CN 110307143 B CN110307143 B CN 110307143B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/26—Control
- F04B1/28—Control of machines or pumps with stationary cylinders
- F04B1/29—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
- F04B1/295—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/26—Control
- F04B1/30—Control of machines or pumps with rotary cylinder blocks
- F04B1/32—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block
- F04B1/324—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Servomotors (AREA)
Abstract
The invention relates to a variable servo valve, a power servo valve and a variable pump. The valve comprises a valve body, wherein a power valve and a discharge valve are arranged in the valve body side by side; the power valve comprises a power valve sleeve and a power valve core, the power valve sleeve can be arranged in the valve body in an axially sliding manner, and the power valve core can be arranged in the power valve sleeve in an axially sliding manner; the displacement valve comprises a displacement valve sleeve and a displacement valve core, the displacement valve sleeve is arranged in the valve body in an axial sliding mode, and the displacement valve core is arranged in the displacement valve sleeve in an axial sliding mode; the feedback rod simultaneously drives the power valve sleeve and the displacement valve sleeve to move under the action of feedback force so as to restore balance; the control oil ports on the power valve sleeve and the displacement valve sleeve are communicated with each other, and the oil port of the servo piston large cavity of the power valve sleeve is controlled by the power valve core to be communicated with the pressure oil port of the power valve sleeve or communicated with the control oil port of the power valve sleeve. The problems of complex structure, large number of parts, difficult processing and assembly and high cost of the displacement control device in the prior art are solved.
Description
Technical Field
The invention relates to the field of hydraulic controllers, in particular to a variable servo valve, a power servo valve and a variable pump.
Background
In a hydraulic excavator, a loader, a crane, a bulldozer, a cement pump truck, and other machines used in construction machinery, a hydraulic actuator such as an oil cylinder is used to drive the machines to move. Various actuators are used, and oil pressure is used for driving these actuators. Under different working conditions and on different machines, the movement forms of the actuators are diversified and randomized, so that a hydraulic pump of a power device used on the engineering machine is required to output different flow rates according to different working conditions to meet the mechanical operation.
Japanese patent No. JP6276664B2, for example, discloses a flow control device of a variable displacement hydraulic pump, which is a commonly used displacement and power combined control device of a hydraulic pump at present, and specifically discloses: the method comprises the following steps: servo mechanism, control valve mechanism, power control mechanism and shutdown mechanism all act on the case through the feedback rod, the feedback rod is connected with the case, through the removal of feedback rod control case, and then the oil feed and the draining of control servo mechanism's big chamber, servo piston controls the change at sloping cam plate inclination under the effect of the pressure differential of both sides oil pocket, and then the discharge capacity of control hydraulic pump, servo piston's motion is again through feedback rod feedback to control valve, thereby make the oil circuit of control valve close, reach new equilibrium point, accomplish discharge capacity control and power control. However, the power control mechanism and the cut-off mechanism are required to be arranged in the structure to feed back the power control mechanism and the cut-off mechanism to the control valve through the feedback rod, the structure is complex, the number of parts is large, the machining is difficult, the cost is high, and the assembly is not easy.
Disclosure of Invention
The invention provides a variable servo valve, a power servo valve and a variable pump, and aims to solve the problems of complex structure, more parts, difficulty in processing and assembling and high cost of a flow control device of a hydraulic pump in the prior art. The technical scheme of the invention is as follows:
a variable servo valve comprising: the valve body is internally provided with a power valve and a discharge valve in parallel; the power valve comprises a power valve sleeve and a power valve core, the power valve sleeve is axially and slidably arranged in the valve body, and the power valve core is axially and slidably arranged in the power valve sleeve; the displacement valve comprises a displacement valve sleeve and a displacement valve core, the displacement valve sleeve is arranged in the valve body in an axial sliding mode, and the displacement valve core is arranged in the displacement valve sleeve in an axial sliding mode; the feedback rod simultaneously drives the power valve sleeve and the displacement valve sleeve to move under the action of feedback force so as to restore balance; the control oil ports on the power valve sleeve and the displacement valve sleeve are communicated with each other, the oil port of the servo piston large cavity of the power valve sleeve is controlled by the power valve core and communicated with the pressure oil port of the power valve sleeve or communicated with the control oil port of the power valve sleeve, and the control oil port of the displacement valve sleeve is controlled by the displacement valve core and communicated with the pressure oil port of the displacement valve sleeve or communicated with the oil return port of the displacement valve sleeve.
The power valve and the discharge valve are arranged in the valve body side by side, so that the adjustment and control of the power and the discharge of the variable pump can be realized respectively; the variable displacement pump is controlled respectively through valve barrel case structure to power valve and discharge capacity valve, through setting up the power case, the discharge capacity case is respectively along the power valve barrel, the break-make between the hydraulic fluid port is controlled in the slip of discharge capacity valve barrel, and then realize oil feed and draining, the power valve barrel, the discharge capacity valve barrel is respectively relative power case under the effect of feedback rod, the slip of discharge capacity case, can make the power case, the discharge capacity case is in balanced state again, realize the effect of adjusting power and discharge capacity, compare in prior art, this application need not to set up structures such as power control mechanism and shutdown mechanism and act on the feedback rod, rethread feedback rod acts on the case, the structure has been simplified greatly, the assembly degree of difficulty and cost have been reduced.
Further, during power adjustment, the control oil port and the oil return port of the displacement valve sleeve are communicated, and when the power valve core moves axially, pressure oil is enabled to sequentially pass through the pressure oil port of the power valve sleeve and the large cavity oil port of the servo piston to apply oil pressure or hydraulic oil is enabled to sequentially pass through the large cavity oil port of the servo piston, the control oil port of the power valve sleeve, the control oil port of the displacement valve sleeve and the oil return port to release pressure.
Through the structure, the constant power control of the variable pump can be realized (namely pq is a constant, p is the pump outlet pressure of the variable pump, and q is the pump displacement of the variable pump): and (3) communicating an oil discharge port of the variable displacement pump with a pressure oil port of the power valve sleeve, wherein the oil pressure of the pressure oil is p. In an initial state, the power valve is in a balanced state, and a pressure oil port, a control oil port and a servo piston large cavity oil port of the power valve sleeve are not communicated; when the pressure of the pressure oil rises, the pressure oil pushes the power valve core to move along the X direction, so that a pressure oil port of the power valve sleeve is communicated with a large servo piston cavity oil port, the pressure oil sequentially passes through the pressure oil port of the power valve sleeve and the large servo piston cavity oil port to apply the oil pressure to the large servo piston cavity, the pressure in the large servo piston cavity is greater than the pressure in the small servo piston cavity, the servo piston pushes a swash plate of the plunger pump to move, the swing angle of the swash plate is reduced, the pump displacement is reduced by q, and the power is constant. In the process that the swing angle of the swash plate is reduced, the feedback rod acts on the power valve sleeve to enable the power valve sleeve to slide along the X direction, and the pressure oil port of the power valve sleeve and the oil port of the large cavity of the servo piston are gradually closed to enable the power valve core to tend to be in a balanced state again; when the pressure of the pressure oil is reduced, the power valve core moves along the-X direction, so that the oil port of the large cavity of the servo piston is communicated with the control oil port of the power valve sleeve, the hydraulic oil in the large cavity of the servo piston sequentially passes through the oil port of the large cavity of the servo piston, the control oil port of the power valve sleeve, the control oil port of the displacement valve sleeve and the oil return port to be decompressed, the pressure in the large cavity of the servo piston is smaller than the pressure in the small cavity of the servo piston, the servo piston pushes the swash plate of the plunger pump to move, the swing angle of the swash. In the process that the swing angle of the swash plate is increased, the feedback rod acts on the power valve sleeve to enable the power valve sleeve to slide along the-X direction, the oil port of the large cavity of the servo piston and the control oil port of the power valve sleeve are gradually closed, and the power valve core is enabled to tend to be in a balanced state again.
Further, the power adjusting assembly is arranged on one side of the power valve core and abuts against the power valve core. The variable characteristic of the power control can be adjusted according to the requirement by arranging the power adjusting component.
And the power pilot valve is positioned on the other side of the power valve core and is used for driving the power valve core to move axially.
Through setting up the power pilot valve on the power valve, accessible power pilot valve provides power pilot pressure to the power case and drives power case axial motion, and its oil feed and draining process are the same with the constant power control process, promptly under the invariable condition of pressure oil, adjusts the control discharge capacity through power pilot pressure, realizes the variable power control (p is invariable promptly, and q changes, then pq changes) to the variable displacement pump.
Further, during displacement adjustment, the big chamber hydraulic fluid port of servo piston keeps the intercommunication with the control hydraulic fluid port of power valve barrel, displacement case axial displacement makes pressure oil loop through the pressure hydraulic fluid port of displacement valve barrel, the control hydraulic fluid port of power valve barrel and the big chamber hydraulic fluid port of servo piston is in order to exert the oil pressure or make hydraulic oil loop through the big chamber hydraulic fluid port of servo piston, the control hydraulic fluid port of power valve barrel, the control hydraulic fluid port of displacement valve barrel and the oil return opening is in order to release the pressure.
Through above-mentioned structure, can carry out the discharge capacity to the variable displacement pump and adjust: and an oil discharge port of the variable displacement pump is communicated with a pressure oil port of the displacement valve sleeve. In an initial state, the displacement valve is in a balanced state, and a pressure oil port of the displacement valve sleeve, a control oil port of the displacement valve sleeve and an oil return port are not communicated; the displacement case moves along the X direction for the pressure hydraulic fluid port of displacement valve barrel and the control hydraulic fluid port of displacement valve barrel communicate, and pressure oil loops through the pressure hydraulic fluid port of displacement valve barrel, the control hydraulic fluid port of displacement valve barrel and the big chamber hydraulic fluid port of servo piston in order to exert the oil pressure to the big chamber of servo piston, and the big intracavity pressure of servo piston is greater than the little intracavity pressure of servo piston, and servo piston promotes the swash plate motion of plunger pump, makes the pivot angle of swash plate diminish, and the pump discharge capacity reduces. In the process that the swing angle of the swash plate is reduced, the feedback rod acts on the displacement valve sleeve to enable the displacement valve sleeve to slide along the X direction, and the pressure oil port and the control oil port of the displacement valve sleeve are gradually closed to enable the displacement valve core to tend to a balanced state again; the displacement valve core moves along the-X direction, so that a control oil port and an oil return port of the displacement valve sleeve are communicated, hydraulic oil in a large servo piston cavity sequentially passes through a large servo piston cavity oil port, a control oil port of the displacement valve sleeve, a control oil port of the power valve sleeve and the oil return port to be decompressed, pressure in the large servo piston cavity is smaller than pressure in a small servo piston cavity, a servo piston pushes a swash plate of the plunger pump to move, the swing angle of the swash plate is increased, and the displacement of the pump is reduced. In the process that the swing angle of the swash plate is increased, the feedback rod acts on the displacement valve sleeve to enable the displacement valve sleeve to slide along the-X direction, the control oil port and the oil return port of the displacement valve sleeve are gradually closed, and the power valve core is enabled to tend to be in a balanced state again.
Further, the displacement control valve further comprises a displacement adjusting assembly, wherein the displacement adjusting assembly is located on one side of the displacement valve core and abuts against the displacement valve core. The variable characteristic of the displacement control can be adjusted according to the requirement by arranging the displacement adjusting assembly.
And the displacement pilot valve is positioned on the other side of the displacement valve core and is used for driving the displacement valve core to axially move.
Through set up the discharge capacity pilot valve on the displacement valve, accessible discharge capacity pilot valve provides the pilot pressure to the discharge capacity case and drives discharge capacity case axial motion, realizes the oil feed and the draining in the big chamber of servo piston.
Furthermore, one end of the feedback rod is connected with the servo piston through a shifting fork, the middle of the feedback rod is a hinged point, the other end of the feedback rod is hinged with a control pin, and two ends of the control pin are respectively connected with the power valve sleeve and the displacement valve sleeve. The feedback rod drives the displacement valve sleeve and the power valve sleeve to move, no additional acting force exists between the displacement valve sleeve and the power valve sleeve, the service life of the feedback rod is prolonged, and the control precision is high.
A variable displacement pump comprises a pump body, a servo piston and the variable servo valve, wherein the pump body is matched with the servo piston and the variable servo valve to adjust the displacement and the power of the pump body.
Furthermore, the pump body is a variable plunger pump, an oil discharge port of the variable plunger pump is communicated with the pressure oil port of the power valve sleeve and the pressure oil port of the displacement valve sleeve, and a piston rod of the servo piston is connected with a swash plate of the variable plunger pump.
The servo piston is controlled to move through the variable servo valve, and the servo piston adjusts the displacement and the power of the pump body, so that variable adjustment of the pump is achieved.
The power servo valve is characterized by comprising the variable servo valve, the number of the pressure oil ports of the power valve sleeves is two, and two pressure steps formed on the power valve core correspond to the pressure oil ports of the two power valve sleeves respectively.
The variable displacement pump comprises two variable displacement plunger pumps and two power servo valves, wherein oil discharge ports of the two variable displacement plunger pumps are communicated with two pressure oil ports of each power valve sleeve.
Two pressure oil ports are arranged to realize that two pressure oils act on the power valve core, so that the cross control of the power valve core can be realized; and the oil discharge ports of the two variable plunger pumps are further communicated with the two pressure oil ports, so that in the control process, the outlet pressure of the first variable plunger pump can influence the power of the second variable plunger pump, and the outlet pressure of the second variable plunger pump can influence the power of the first variable plunger pump, thereby realizing cross power control.
Based on the technical scheme, the invention can realize the following technical effects:
1. according to the variable servo valve, the power servo valve and the variable pump, the power valve and the discharge valve are arranged in the valve body side by side, so that the adjustment control of the power and the discharge of the variable pump can be realized respectively; the power valve and the displacement valve respectively control the variable displacement pump through a valve sleeve and valve core structure, oil inlet and oil drainage of a large cavity of a servo piston are controlled by arranging the power valve core and the displacement valve core to respectively slide along the power valve sleeve and the displacement valve sleeve, the power valve sleeve and the displacement valve sleeve respectively slide relative to the power valve core and the displacement valve core under the action of the feedback rod, the power valve core and the displacement valve core can be in a balanced state again, and the effect of adjusting power and displacement is realized;
2. the variable servo valve, the power servo valve and the variable pump can realize constant power regulation and variable power regulation of the variable pump through the power valve: in the process of constant power regulation, the pump displacement of the variable pump is regulated by taking the outlet pressure of the variable pump as a variable, and as a pressure oil port is communicated with an oil discharge port of the variable pump, pressure oil is oil discharged by the variable pump, so that when the outlet pressure of the variable pump is increased, the oil pressure of the pressure oil entering the pressure oil port of the power valve is increased, the acting force of the pressure oil on the area difference of the power valve core is increased, the power valve core is driven to move, a large cavity of a servo piston is filled with oil, the swing angle of a swash plate is reduced, the pump displacement of the variable pump is reduced, and the constant power is realized; on the contrary, when the oil pressure of the pressure oil is reduced, the large cavity of the servo piston drains oil, the swing angle of the swash plate is increased, the pump displacement of the variable pump is increased, and the constant power is realized, namely pq is a constant, wherein p is the pump outlet pressure of the variable pump, and q is the pump displacement of the variable pump. In the variable power adjusting process, the displacement of the variable pump is adjusted through the power pilot valve, the oil pressure of the pressure oil can be kept constant, the power is increased due to the fact that the pump displacement of the variable pump is increased, and the power is decreased due to the fact that the pump displacement of the variable pump is decreased. The displacement of the variable displacement pump can be adjusted through the displacement valve, and the displacement of the variable displacement pump is adjusted through the action of the displacement pilot valve on the displacement valve core. The constant power regulation, the variable power regulation and the displacement regulation can respectively realize the regulation function of the variable pump, and in the actual use, the comprehensive regulation of the constant power regulation, the variable power regulation and the displacement regulation can be carried out to meet different power requirements under different displacements during the mechanical operation;
3. according to the variable servo valve, the power servo valve and the variable pump, the control oil ports on the power valve sleeve and the displacement valve sleeve are communicated with each other, and the control oil port of the displacement valve sleeve is communicated with the oil return port during power adjustment, so that the power valve can control oil inlet and oil discharge of a large cavity of a servo piston as required; when the displacement is adjusted, the oil port of the large cavity of the servo piston is communicated with the control oil port of the power valve sleeve, so that the displacement valve can control oil inlet and oil drainage of the large cavity of the servo piston as required. The oil ports on the power valve sleeve and the displacement valve sleeve are reasonably communicated, and the power valve and the displacement valve are matched with each other to work, so that the arrangement of the oil ports can be reduced on the basis of realizing the control on an oil way as required, and the structure is simplified;
4. according to the variable servo valve, the power servo valve and the variable pump, the power regulating assembly is arranged on the power valve, the displacement regulating assembly is arranged on the displacement valve, the power regulating assembly adopts the large elastic piece and the small elastic piece with adjustable positions, the variable characteristic of power control can be regulated according to the requirement, and the controllability of power regulation is improved; the displacement adjusting assembly also adopts an elastic part structure with adjustable position, and the variable characteristic of displacement control can be adjusted according to the requirement;
5. the power servo valve and the variable displacement pump can realize cross power regulation of double pumps, and can realize that two pumps act on a power valve core by arranging two pressure oil ports of the power valve sleeve and respectively communicating with oil discharge ports of the two pumps, so that the outlet pressure of a first variable displacement plunger pump can influence the power of a second variable displacement plunger pump, the outlet pressure of the second variable displacement plunger pump can influence the power of the first variable displacement plunger pump in the control process, and cross power control is realized.
Drawings
FIG. 1 is a schematic diagram of the construction of a variable servo valve of the present invention;
FIG. 2 is an enlarged view of portion A of FIG. 1;
FIG. 3 is an enlarged view of portion B of FIG. 1;
FIG. 4 is a schematic diagram of the distribution of oil ports on the variable servo valve;
FIG. 5 is a schematic diagram of a variable servo valve;
6(a) -6(c) are schematic diagrams of the operation of the variable servo valve in the constant power mode of operation;
FIG. 7 is a graph of the variable servo valve acting under variable power control;
8(a) -8(c) are schematic diagrams of the variable displacement servo valve operating during displacement adjustment;
FIG. 9 is a schematic view of the feedback rod;
FIGS. 10(a) -10(b) are schematic diagrams of the feedback lever acting on the power valve;
FIG. 11 is a graph illustrating the combined effect of displacement adjustment and power adjustment;
fig. 12 is a schematic diagram of a power servo valve.
In the figure: 1-a valve body; 2-a power valve; 21-power valve housing; 22-power spool; 221-a first core; 2211-power throttle slot; 222-a second core; 223-a third core; 224-a first step; 3-a discharge valve; 31-a displacement valve sleeve; 32-displacement spool; 321-a fourth core; 3211-displacement throttling groove; 322-a fifth core; 323-second step; 4-a power regulating component; 41-a first elastic member; 411-large elastic member; 412-a small elastic member; 42-an adjustment assembly; 421-adjusting screw sleeve; 422-power adjusting screw; 5-a power pilot valve; 51-power pilot valve sleeve; 52-power pilot valve core; 6-a displacement adjustment assembly; 61-a second elastic member; 62-an adjustment member; 63-a third step; 7-a displacement pilot valve; 71-displacement pilot valve sleeve; 72-displacement pilot spool; 8-a feedback rod; 81-a shifting fork; 82-a control pin; 83-rotational locating pins; 84-a positioning element; 9-a pilot cover plate; 10-adjusting the cover plate; 01-servo piston large cavity; 02-a servo piston small cavity; 03-a servo piston; 04-pump body; p-the oil discharge port of the variable displacement pump; po 1-pressure port of power valve sleeve; pt 1-control oil port of power valve sleeve; ps-a large cavity oil port of the servo piston; ai-power pilot pressure; po 2-pressure port of displacement valve sleeve; pt 2-control oil port of displacement valve sleeve; t-oil return port; pi-displacement pilot pressure.
Detailed Description
The invention is further described with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "radial," "axial," "upper," "lower," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and thus are not to be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Example one
As shown in fig. 1 to 11, the present embodiment provides a variable servo valve, which includes a valve body 1, a power valve 2 and a displacement valve 3 are arranged in the valve body 1 side by side, specifically, two mounting holes are formed in the valve body 1 in parallel, and the power valve 2 and the displacement valve 3 are respectively arranged in the two mounting holes. The power valve 2 and the displacement valve 3 can realize power control and displacement control of the variable displacement pump by controlling the movement of the servo piston. The power valve 2 and the displacement valve 3 can be controlled separately or in coordination.
The power valve 2 includes a power valve sleeve 21 and a power valve spool 22, the power valve sleeve 21 is axially slidably disposed in the valve body 1, and the power valve spool 22 is axially slidably disposed in the power valve sleeve 21. The power valve housing 21 is provided with a pressure oil port Po1 of the power valve housing, a large cavity oil port Ps of the servo piston and a control oil port Pt1 of the power valve housing, pressure oil enters between the power valve housing 21 and the power valve core 22 from the pressure oil port Po1 of the power valve housing, the large cavity oil port Ps of the servo piston is communicated with the large cavity 01 of the servo piston, and the large cavity oil port Ps of the servo piston is controlled by the power valve core 22 to be communicated with the pressure oil port Po1 of the power valve housing or communicated with the control oil port Pt1 of the power valve housing. Specifically, the large cavity oil port Ps of the servo piston is located between the pressure oil port Po1 of the power valve sleeve and the control oil port Pt1 of the power valve sleeve, the first core body 221 and the second core body 222 are arranged on the power valve core 22 at intervals, in the initial state of the power valve, the first core body 221 covers the large cavity oil port Ps of the servo piston, and the pressure oil port Po1 of the power valve sleeve is located between the first core body 221 and the second core body 222. When the first core body 221 covers the large cavity oil port Ps of the servo piston, the large cavity oil port Ps of the servo piston is not communicated with the pressure oil port Po1 of the power valve sleeve and the control oil port Pt1 of the power valve sleeve; when the first core body 221 slides towards the control oil port Pt1 of the power valve sleeve, the large cavity oil port Ps of the servo piston is gradually opened, the large cavity oil port Ps of the servo piston is communicated with the pressure oil port Po1 of the power valve sleeve, and pressure oil can enter the large cavity 01 of the servo piston through the pressure oil port Po1 of the power valve sleeve and the large cavity oil port Ps of the servo piston in sequence to apply oil pressure; when the first core body 221 slides towards the pressure port Po1 of the power valve housing, the large cavity port Ps of the servo piston is gradually opened, the large cavity port Ps of the servo piston is communicated with the control port Pt1 of the power valve housing, hydraulic oil in the large cavity of the servo piston enters the control port Pt1 of the power valve housing through the large cavity port Ps of the servo piston, and the control port Pt1 of the power valve housing can be directly communicated with the oil return port to return the hydraulic oil. Preferably, the outer diameter of the first core 221 is D1, the outer diameter of the second core 222 is D2, D1 > D2, and an area difference S1 is formed between the first core 221 and the second core 222, thereby forming a pressure step. Further preferably, power throttling grooves 2211 are formed in positions, corresponding to the oil ports, of the two ends of the first core 221, and as shown in fig. 2, by forming the power throttling grooves 2211, when the power valve core 22 slides along the power valve sleeve 21 to communicate with different oil paths, the opening and closing of the oil ports can be changed smoothly by the power throttling grooves 2211, so that the stability of the power valve 2 is improved.
One end of the power valve 2 is provided with a power adjusting component 4, and the variable characteristic of power control can be adjusted through the power adjusting component 4. Specifically, the power adjustment assembly 4 is disposed at an end of the power spool 22 of the power valve 2 away from the second core 222, such that pressurized oil may move the power spool 22 against the force of the power adjustment assembly 4. The power control assembly 4 comprises a first spring element 41 and a control assembly 42, the control assembly 42 is arranged on the valve body 1 in a position-adjustable manner, the first spring element 41 is located between the power valve spool 22 and the control assembly 42, one end of the first spring element 41 acts on the control assembly 42, and the other end of the first spring element 41 acts on the power valve spool 22. Specifically, the first elastic element 41 includes a large elastic element 411 and a small elastic element 412, in this embodiment, the small elastic element 412 may be sleeved in the large elastic element 411, the adjusting assembly 42 includes an adjusting nut 421 and a power adjusting screw 422, one end of the valve body 1 is provided with an adjusting cover plate 10, an outer surface of the adjusting nut 421 is provided with an external thread, the adjusting nut 421 is in threaded connection with the adjusting cover plate 10, at least a portion of the adjusting nut 421 penetrates through the adjusting cover plate 10 and extends into the valve body 1, the power adjusting screw 422 is disposed inside the adjusting nut 421, the power adjusting screw 422 is in threaded connection with the adjusting nut 421, the relative positions of the adjusting nut 421, the power adjusting screw 422 and the valve body 1 may be adjusted by rotating the adjusting nut 421, and the relative positions of the adjusting nut 421 and the power adjusting screw 422 may be adjusted by rotating the power adjusting screw 22. One end of the large elastic element 411 abuts against the adjusting screw 421, one end of the small elastic element 412 abuts against the power adjusting screw 422, and the other ends of the large elastic element 411 and the small elastic element 412 act on the power valve core 22. Preferably, an inner hole of the adjusting screw sleeve 421 near one end of the large elastic member 411 is an outward-expanding stepped inner hole, an end of the power adjusting screw 422 near the small elastic member 412 is stepped, and an end of the power adjusting screw 422 near the small elastic member 412 can at least partially extend into the small elastic member 412, so that the large elastic member 411 and the small elastic member 412 can be limited, and the large elastic member 411 and the small elastic member 412 can also be prevented from being distorted and deformed. Further preferably, one end of the power valve core 22 close to the first elastic member 41 is connected to a first step member 224, one end of the first step member 224 facing the first elastic member 41 is stepped, and at least a portion of the large elastic member 411 and the small elastic member 412 may be sleeved outside the first step member 224 to limit the first elastic member 41. Preferably, the large elastic member 411 and the small elastic member 412 may be selected, but not limited to, springs.
The other end of the power valve 2 is provided with a power pilot valve 5, the power pilot valve 5 comprises a power pilot valve sleeve 51 and a power pilot valve core 52, the power pilot valve core 52 is slidably arranged inside the power pilot valve sleeve 51, under the action of a power adjusting signal (namely, power pilot pressure Ai), the power pilot valve core 52 generates a certain acting force, the power pilot pressure Ai is increased, the acting force of the first elastic piece 41 is overcome, and the power pilot valve core 52 pushes the power valve core 22 to move towards the X direction; conversely, the power pilot pressure Ai decreases, the acting force of the first elastic element 41 is greater than the power pilot pressure Ai, and the first elastic element 41 pushes the power spool 22 to move in the-X direction.
The displacement valve 3 includes a displacement valve sleeve 31 and a displacement spool 32, the displacement valve sleeve 31 being axially slidably disposed in the valve body 1, and the displacement spool 32 being axially slidably disposed in the displacement valve sleeve 31. The displacement valve sleeve 31 is provided with a pressure port Po2 of the displacement valve sleeve, a control port Pt2 of the displacement valve sleeve and an oil return port T, pressure oil enters between the displacement valve sleeve 31 and the displacement valve core 32 from the pressure port Po2 of the displacement valve sleeve, and the control port Pt2 of the displacement valve sleeve is controlled by the displacement valve core 32 to be communicated with the pressure port Po2 of the displacement valve sleeve or communicated with the oil return port T. The control oil port Pt2 of the displacement valve sleeve is communicated with the control oil port Pt1 of the power valve sleeve, so that the control oil port Pt2 of the displacement valve sleeve of the control displacement valve 3 is communicated with the oil return port T, and therefore when the power valve 2 works, the control oil port Pt1 of the power valve sleeve is communicated with the oil return port T through the control oil port Pt2 of the displacement valve sleeve, and oil drainage when the power valve 2 works is achieved; the control oil port Pt1 of the power valve sleeve of the control power valve 2 is communicated with the oil port Ps of the large cavity of the servo piston, so that the control oil port Pt2 of the displacement valve is communicated with the oil port Ps of the large cavity of the servo piston through the control oil port Pt1 of the power valve sleeve when the displacement valve 3 works, and oil feeding of the displacement valve during working is realized.
Specifically, the control oil port Pt2 of the displacement valve sleeve is located between the pressure oil port Po2 and the oil return port T of the displacement valve sleeve, and the fourth core 321 and the fifth core 322 are arranged on the displacement valve core 32 at intervals. In an initial state, when the fourth core 321 covers the control oil port Pt2 of the displacement valve sleeve, the control oil port Pt2 of the displacement valve sleeve is not communicated with the pressure oil port Po2 and the oil return port T of the displacement valve sleeve, and the pressure oil port Po2 of the displacement valve sleeve is located between the fourth core 321 and the fifth core 322; when the fourth core 321 slides towards the oil return port T, the control port Pt2 of the displacement valve sleeve is gradually opened, the pressure port Po2 of the displacement valve sleeve is communicated with the control port Pt2 of the displacement valve sleeve, and the pressure oil can sequentially pass through the pressure port Po2 of the displacement valve sleeve, the control port Pt2 of the displacement valve sleeve, the control port Pt1 of the power valve sleeve and the large cavity port Ps of the servo piston to apply oil pressure; when the fourth core 321 slides towards the pressure port Po2 of the displacement valve sleeve, the control port Pt2 of the displacement valve sleeve is gradually opened, the control port Pt2 of the displacement valve sleeve is communicated with the oil return port T, and hydraulic oil in the large cavity of the servo piston sequentially passes through the large cavity oil port Ps of the servo piston, the control port Pt1 of the displacement valve sleeve, the control port Pt2 of the displacement valve sleeve and the oil return port T to drain oil. Preferably, the displacement throttling grooves 3211 are disposed at positions corresponding to the oil ports at two ends of the fourth core 321, as shown in fig. 3, by disposing the displacement throttling grooves 3211, when the displacement valve core 32 slides along the displacement valve sleeve 31 to communicate with different oil paths, the opening and closing of the oil ports tend to change smoothly, so as to improve the stability of the displacement valve 3.
One end of the discharge valve 3 is provided with a displacement adjusting assembly 6, and the variable characteristic of the displacement control can be adjusted through the displacement adjusting assembly 6. Specifically, the displacement adjusting assembly 6 includes a second elastic member 61 and an adjusting member 62, the adjusting member 62 is movably disposed on the adjusting cover plate 10, the adjusting member 62 can drive a third step member 63 slidably disposed in the valve body 1 to move in the axial direction, and the second elastic member 61 is located between the displacement spool 32 and the third step member 63. Preferably, one end of the displacement valve core 32 close to the second elastic member 61 is provided with a second step 323, and at least parts of the second step 323 and the third step 63 respectively extend into two ends of the second elastic member 61, so that the second elastic member 61 can be limited and the second elastic member 61 can be prevented from being distorted. Preferably, the second elastic member 61 may be selected from, but not limited to, a spring.
The other end of the displacement valve 3 is provided with a displacement pilot valve 7, the displacement pilot valve 7 comprises a displacement pilot valve sleeve 71 and a displacement pilot valve core 72, the displacement pilot valve core 72 is slidably arranged in the displacement pilot valve sleeve 71, under the action of a displacement adjusting signal (namely, displacement pilot pressure Pi), the displacement pilot valve core 72 generates a certain acting force, the displacement pilot pressure Pi is increased, the acting force of the second elastic element 61 is overcome, and the displacement pilot valve core 72 pushes the displacement valve core 32 to move towards the X direction; on the contrary, the displacement pilot pressure Pi decreases, the second elastic member 61 has a force greater than the displacement pilot pressure Pi, and the second elastic member 61 pushes the displacement spool 32 to move in the-X direction.
A feedback rod 8 is further arranged in the valve body 1, one end of the feedback rod 8 is connected with the servo piston 03, and the other end of the feedback rod 8 drives the power valve sleeve 21 and the displacement valve sleeve 31 to move simultaneously under the feedback force action of the servo piston 03 so as to restore the balance between the power valve core 22 and the displacement valve core 32. Specifically, the middle part of the feedback rod 8 is swingably disposed in the valve body 1 through a rotational positioning pin 83, one end of the feedback rod 8 is connected to the piston rod of the servo piston 03 through a shift fork 81, the other end of the feedback rod 8 is connected to a control pin 82, two ends of the control pin 82 are respectively connected to the power valve housing 21 and the displacement valve housing 31, and the control pin 82 is movable in the two valve housings. As shown in fig. 10(a), when the displacement of the variable displacement pump is reduced, the servo piston 03 drives the power valve sleeve 21 and the displacement valve sleeve 31 to move along the X direction through the feedback rod 8; as shown in fig. 10(b), when the displacement of the variable displacement pump is reduced, the servo piston 03 drives both the power valve sleeve 21 and the displacement valve sleeve 31 to move in the-X direction through the feedback rod 8. Preferably, a positioning member 84 is further included, and the positioning member 84 is used for limiting the movable range of the feedback rod 8.
Based on the above structure, the working principle of the variable servo valve in this embodiment when controlling the variable plunger pump is as follows: a pressure oil port Po1 of a power valve sleeve of the variable servo valve and a pressure oil port Po2 of a displacement valve sleeve are both communicated with an oil discharge port of the variable plunger pump, and a small servo piston cavity 02 is communicated with the oil discharge port of the variable plunger pump;
as shown in fig. 6(a) -6(c), the variable displacement plunger pump is regulated at constant power using the power valve 2: in an initial state, as shown in fig. 6(a), the power valve 2 is in a neutral position (i.e., a balanced state), the pressure port Po1 of the power valve sleeve, the control port Pt1 of the power valve sleeve and the large cavity port Ps of the servo piston are not communicated, and the control port Pt2 of the displacement valve sleeve in the displacement valve 3 is communicated with the oil return port T. When the pressure p of the pressure oil rises, the pressure oil pushes the power valve core 22 to move along the direction X, the power valve 2 is in the left position, a pressure oil port Po1 of a power valve sleeve in the power valve 2 is communicated with a large servo piston cavity oil port Ps, the pressure oil sequentially passes through the pressure oil port Po1 of the power valve sleeve and the large servo piston cavity oil port Ps to apply the oil pressure to the large servo piston cavity 01, the pressure in the large servo piston cavity 01 is greater than that in the small servo piston cavity 02, the servo piston 03 pushes a swash plate of the variable displacement plunger pump to move, the swing angle of the swash plate is reduced, the pump displacement q is reduced, and the power is constant. In the process that the swing angle of the swash plate is reduced, the feedback rod 8 acts on the power valve sleeve 21 to enable the power valve sleeve 21 to slide along the X direction, the pressure oil port Po1 of the power valve sleeve and the large cavity oil port Ps of the servo piston are gradually closed, and the power valve core 22 tends to be in a balanced state again; when the pressure oil pressure p is reduced, the power valve core 22 moves along the-X direction, the power valve 2 is located at the right position, a servo piston large cavity oil port Ps in the power valve 2 is communicated with a control oil port Pt1 of the power valve sleeve, the hydraulic oil in the servo piston large cavity sequentially passes through the servo piston large cavity oil port Ps, the control oil port Pt1 of the power valve sleeve, the control oil port Pt2 of the displacement valve sleeve and an oil return port T for oil drainage, the pressure in the servo piston large cavity 01 is smaller than the pressure in the servo piston small cavity 02, the servo piston 03 pushes a swash plate of the variable displacement plunger pump to move, the swing angle of the swash plate is increased, the pump displacement is decreased by q, and the. In the process that the swing angle of the swash plate is increased, the feedback rod 8 acts on the power valve sleeve 21 to enable the power valve sleeve 21 to slide along the-X direction, the oil port Ps of the large cavity of the servo piston and the control oil port Pt1 of the power valve sleeve are gradually closed, and the power valve core 22 tends to be in a balanced state again.
The variable power adjustment is carried out on the variable plunger pump by adopting a power valve 2: in an initial state, the power valve 2 is in a balanced state under the action of the first elastic piece 41, the pressure oil port Po1 of the power valve sleeve, the control oil port Pt1 of the power valve sleeve and the large cavity oil port Ps of the servo piston are not communicated, and the control oil port Pt2 of the displacement valve sleeve in the displacement valve 3 is communicated with the oil return port T. The power pilot valve 5 provides power pilot pressure Ai for the power valve core 22, when the power pilot pressure Ai is increased, the power pilot valve core 52 can push the power valve core 22 to overcome the acting force of the first elastic piece 41, so that the power valve core 22 in an initial balance state moves towards the X direction, a pressure oil port Po1 of the power valve sleeve is communicated with a large cavity oil port Ps of the servo piston, the pressure oil sequentially passes through the pressure oil port Po1 of the power valve sleeve and the large cavity oil port Ps of the servo piston to apply oil pressure to the large cavity 01 of the servo piston, the pressure in the large cavity 01 of the servo piston is greater than the pressure in the small cavity 02 of the servo piston, the servo piston 03 pushes a swash plate of the variable displacement plunger pump to move, the swing angle of the swash plate is reduced, the pump displacement q is. In the process that the swing angle of the swash plate is reduced, the feedback rod 8 acts on the power valve sleeve 21 to enable the power valve sleeve 21 to slide along the X direction, the pressure oil port Po1 of the power valve sleeve and the large cavity oil port Ps of the servo piston are gradually closed, and the power valve core 22 tends to be in a balanced state again; when the power pilot pressure Ai is smaller than the acting force of the first elastic piece 41, the power valve core 22 moves along-X under the action of the first elastic piece 41, so that the oil port Ps of the large cavity of the servo piston is communicated with the control oil port Pt1 of the power valve sleeve, hydraulic oil in the large cavity of the servo piston sequentially passes through the oil port Ps of the large cavity of the servo piston, the control oil port Pt1 of the power valve sleeve, the control oil port Pt2 of the displacement valve sleeve and the oil return port T for oil drainage, the pressure in the large cavity 01 of the servo piston is smaller than the pressure in the small cavity 02 of the servo piston, the servo piston 03 pushes the swash plate of the variable displacement plunger pump to move, the swing angle of the swash plate is increased. In the process that the swing angle of the swash plate is increased, the feedback rod 8 acts on the power valve sleeve 21 to enable the power valve sleeve 21 to slide along the-X direction, the oil port Ps of the large cavity of the servo piston and the control oil port Pt1 of the power valve sleeve are gradually closed, and the power valve core 22 tends to be in a balanced state again. The action curve of the variable power control is shown in fig. 7.
As shown in fig. 8(a) -8(c), the displacement valve 3 is used to perform displacement adjustment of the variable displacement plunger pump: in an initial state, the displacement valve 3 is in a balanced state under the action of the displacement pilot valve 7 and the second elastic piece, the pressure oil port Po2 of the displacement valve sleeve, the control oil port Pt2 of the displacement valve sleeve and the oil return port T are not communicated, and the control oil port Pt1 of the power valve sleeve in the power valve 2 is communicated with the large cavity oil port Ps of the servo piston; when the displacement signal (i.e., the displacement pilot pressure Pi of the displacement pilot valve 7) increases, the displacement pilot pressure Pi acts on the displacement pilot pressure spool 72, and the generated acting force is greater than the acting force of the second elastic member 61, the displacement pilot spool 72 pushes the displacement spool 22 to move along the X direction, so that the pressure port Po2 of the displacement valve housing is communicated with the control port Pt2 of the displacement valve housing, the pressure oil sequentially passes through the pressure port Po2 of the displacement valve housing, the control port Pt2 of the displacement valve housing, the control port Pt1 of the power valve housing, and the large servo piston cavity port Ps to apply oil pressure to the large servo piston cavity 01, the pressure in the large servo piston cavity 01 is greater than the pressure in the small servo piston cavity 02, and the servo piston 03 pushes the swash plate of the variable displacement plunger pump to move, so that the swing angle of the swash plate becomes smaller. In the process that the swing angle of the swash plate is reduced, the feedback rod 8 acts on the displacement valve sleeve 31 to enable the displacement valve sleeve 31 to slide along the X direction, the pressure oil port Po1 and the control oil port Pt1 of the displacement valve sleeve are gradually closed, and the displacement valve core 32 tends to be in a balanced state again; when the displacement signal (i.e. the displacement pilot pressure Pi of the displacement pilot valve 7) is reduced, the displacement pilot pressure Pi acts on the displacement pilot pressure spool 72, and the generated acting force is smaller than the acting force of the second elastic member 61, the second elastic member 61 pushes the displacement spool 32 to move in the-X direction, so that the control oil port Pt2 of the displacement valve sleeve is communicated with the oil return port T, hydraulic oil in the large servo piston cavity 01 sequentially passes through the large servo piston cavity oil port Ps, the control oil port Pt2 of the displacement valve sleeve and the oil return port T to be decompressed, the pressure in the large servo piston cavity 01 is smaller than the pressure in the small servo piston cavity 02, the servo piston 03 pushes the swash plate of the variable displacement plunger pump to move, the swing angle of the swash plate is increased, and. In the process of increasing the swing angle of the swash plate, the feedback rod 8 acts on the displacement valve sleeve 31 to make the displacement valve sleeve 31 slide along the-X direction, gradually close the control oil port Pt2 and the oil return port T of the displacement valve sleeve, and make the displacement valve core 32 approach the balance state again.
In practical use, different power requirements under different displacements during mechanical operation are met through the combined action of the displacement regulation, the constant power regulation and the power magnitude regulation signals of the pump, and the action curve is shown in fig. 11.
The embodiment also discloses a variable displacement pump, including foretell variable servo valve, still include pump body 04 and servo piston 03, and pump body 04 is the variable plunger pump, and the oil drain port of variable plunger pump all communicates with pressure hydraulic fluid port Po1, the pressure hydraulic fluid port Po2 of discharge capacity valve barrel, servo piston loculus 02, and servo piston 03's piston rod is connected with the sloping cam plate of variable plunger pump, promotes the motion of sloping cam plate through the piston rod, adjusts the angle of sloping cam plate. The adjustment principle of the variable displacement pump is the same as the working principle of the variable servo valve in controlling the variable displacement plunger pump.
Example two
As shown in fig. 12, the present embodiment is substantially the same as the first embodiment, except that there are two pressure ports Po1 of the power valve sleeves, the pressure ports Po1 of the two power valve sleeves are both used for receiving pressure oil, a third core 223 is further disposed on the power valve core 21, the third core 223 is located on one side of the second core 222 away from the first core 221, an outer diameter of the third core 223 is D3, D1 > D2 > D3, an area difference S1 is formed between D1 and D2, and an area difference S2 is formed between D2 and D3, so that two pressure steps are formed. The pressure oil ports Po1 of the two power valve sleeves are respectively located between the first core 221 and the second core 222 and between the second core 222 and the third core 223. The direction of the acting force of the pressure oil entering through the pressure oil ports Po1 of the two power valve sleeves on the power valve core 22 is opposite to the direction of the acting force of the first elastic element 41 on the power valve core 22, so that a power servo valve is formed.
The embodiment also provides a variable displacement pump, including two variable displacement plunger pumps and two above-mentioned power servo valves, two variable displacement plunger pumps are marked as first variable displacement plunger pump and second variable displacement plunger pump, two power servo valves are marked as first power servo valve and second power servo valve, then the oil drain port of first variable displacement plunger pump and the oil drain port of second variable displacement plunger pump communicate with the pressure oil port Po1 of two power valve covers on the first power servo valve respectively, simultaneously, the oil drain port of first variable displacement plunger pump and the oil drain port of second variable displacement plunger pump communicate with the pressure oil port Po1 of two power valve covers on the second power servo valve respectively, realize cross power control.
The working principle of the variable pump is basically the same as that of the variable pump in the first embodiment, and the difference is that two pressure oil flows act on the power valve core in the constant power adjusting process, and the oil inlet and oil discharge processes of the large cavity 01 of the servo piston are the same as those in the first embodiment.
The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.
Claims (12)
1. A variable displacement servo valve comprising:
the valve comprises a valve body (1), wherein a power valve (2) and a displacement valve (3) are arranged in the valve body (1) side by side;
the power valve (2) comprises a power valve sleeve (21) and a power valve core (22), wherein the power valve sleeve (21) is axially slidably arranged in the valve body (1), and the power valve core (22) is axially slidably arranged in the power valve sleeve (21);
the discharge valve (3) comprises a discharge valve sleeve (31) and a discharge valve core (32), the discharge valve sleeve (31) is arranged in the valve body (1) in a sliding mode along the axial direction, and the discharge valve core (32) is arranged in the discharge valve sleeve (31) in a sliding mode along the axial direction;
a feedback rod (8), wherein the feedback rod (8) simultaneously drives the power valve sleeve (21) and the displacement valve sleeve (31) to move under the action of feedback force so as to restore the balance;
the control oil ports on the power valve sleeve (21) and the displacement valve sleeve (31) are communicated with each other, the servo piston large cavity oil port (Ps) of the power valve sleeve (21) is communicated with the pressure oil port (Po 1) of the power valve sleeve controlled by the power valve core (22) or communicated with the control oil port (Pt 1) of the power valve sleeve, the control oil port (Pt 2) of the displacement valve sleeve is communicated with the pressure oil port (Po 2) of the displacement valve sleeve controlled by the displacement valve core (32) or communicated with the oil return port (T) of the displacement valve sleeve (31), and the servo piston large cavity oil port (Ps) of the power valve sleeve (21) is communicated with the servo piston large cavity (01).
2. The variable servo valve of claim 1, wherein during power adjustment, the control oil port (Pt 2) and the oil return port (T) of the displacement valve sleeve are communicated, and when the power valve core (22) moves axially, pressure oil passes through the pressure oil port (Po 1) of the power valve sleeve and the large cavity oil port (Ps) of the servo piston in order to apply oil pressure or hydraulic oil passes through the large cavity oil port (Ps) of the servo piston in order to relieve pressure, the control oil port (Pt 1) of the power valve sleeve, the control oil port (Pt 2) of the displacement valve sleeve and the oil return port (T) in order to relieve pressure.
3. A variable displacement servo valve according to any of claims 1-2, further comprising a power regulating assembly (4), the power regulating assembly (4) being located on one side of the power spool (22) and abutting against the power spool (22).
4. A variable servo valve according to claim 3, further comprising a power pilot valve (5), the power pilot valve (5) being located on the other side of the power spool (22), the power pilot valve (5) being adapted to drive the power spool (22) to move axially.
5. The variable servo valve of claim 1, wherein during displacement adjustment, the large cavity oil port (Ps) of the servo piston and the control oil port (Pt 1) of the power valve sleeve are communicated, and the axial movement of the displacement valve core (32) enables pressure oil to sequentially pass through the pressure oil port (Po 2) of the displacement valve sleeve, the control oil port (Pt 2) of the displacement valve sleeve, the control oil port (Pt 1) of the power valve sleeve and the large cavity oil port (Ps) of the servo piston to apply oil pressure or enables hydraulic oil to sequentially pass through the large cavity oil port (Ps) of the servo piston, the control oil port (Pt 1) of the power valve sleeve, the control oil port (Pt 2) of the displacement valve sleeve and the oil return port (T) to release pressure.
6. A variable displacement servo valve according to claim 1 or 5, further comprising a displacement adjustment assembly (6), the displacement adjustment assembly (6) being located on one side of the displacement spool (32) and abutting against the displacement spool (32).
7. A variable servo valve according to claim 6, further comprising a displacement pilot valve (7), the displacement pilot valve (7) being located on the other side of the displacement spool (32), the displacement pilot valve (7) being adapted to drive the displacement spool (32) in axial movement.
8. A variable servo valve according to claim 1, wherein one end of the feedback rod (8) is connected with the servo piston (03) through a shifting fork (81), the middle part of the feedback rod (8) is a hinged point, the other end of the feedback rod (8) is hinged with a control pin (82), and two ends of the control pin (82) are respectively connected with the power valve sleeve (21) and the displacement valve sleeve (31).
9. Variable displacement pump, characterized in that it comprises a pump body (04), a servo piston (03) and a variable servo valve according to any of claims 1 to 8, the pump body (04) being adjusted in its displacement and power by the cooperation of the servo piston (03) and the variable servo valve.
10. The variable displacement pump of claim 9, wherein the pump body (04) is a variable displacement piston pump, an oil discharge port of the variable displacement piston pump is communicated with the pressure port (Po 1) of the power valve sleeve and the pressure port (Po 2) of the displacement valve sleeve, and a piston rod of the servo piston (03) is connected with a swash plate of the variable displacement piston pump.
11. A power servo valve comprising the variable servo valve according to any one of claims 1 to 8, wherein the number of the pressure ports (Po 1) of the power valve housing is two, and the power valve spool (22) is formed with two pressure steps corresponding to the pressure ports (Po 1) of the two power valve housings, respectively.
12. A variable displacement pump comprising two variable displacement piston pumps and two power servo valves as claimed in claim 11, wherein the oil discharge ports of the two variable displacement piston pumps are communicated with both pressure ports of each of the power valve housings.
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| CN112012972B (en) * | 2020-08-26 | 2022-05-10 | 徐州徐工矿业机械有限公司 | Pilot control oil way and control method for super-tonnage excavator |
| CN113464394B (en) * | 2021-08-20 | 2022-12-13 | 浙江苏强格液压股份有限公司 | Torque control device for plunger pump |
| CN114687979A (en) * | 2022-03-21 | 2022-07-01 | 江苏汇智高端工程机械创新中心有限公司 | Plunger pump flow and power control system |
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| CN108397448A (en) * | 2018-04-23 | 2018-08-14 | 浙江大学宁波理工学院 | Dual valve loads independent control type electro-hydraulic vibration exciter and its electro hydraulic exciting system and bias control method |
| CN108488130A (en) * | 2018-05-18 | 2018-09-04 | 宁波真格液压科技有限公司 | A kind of control valve gear |
| CN108591153A (en) * | 2018-05-18 | 2018-09-28 | 宁波真格液压科技有限公司 | A kind of multi-way valve |
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| CN110307143A (en) | 2019-10-08 |
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