CN112096671A - Variable pump and hydraulic system - Google Patents
Variable pump and hydraulic system Download PDFInfo
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- CN112096671A CN112096671A CN202011063182.9A CN202011063182A CN112096671A CN 112096671 A CN112096671 A CN 112096671A CN 202011063182 A CN202011063182 A CN 202011063182A CN 112096671 A CN112096671 A CN 112096671A
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- 239000003921 oil Substances 0.000 claims description 183
- 238000006073 displacement reaction Methods 0.000 claims description 54
- 239000010720 hydraulic oil Substances 0.000 claims description 36
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000017105 transposition Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/0401—Valve members; Fluid interconnections therefor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20546—Type of pump variable capacity
Abstract
The invention belongs to the technical field of hydraulic pressure, and discloses a variable pump and a hydraulic system. The variable pump comprises a variable pump main body and a variable cylinder, wherein a swash plate of the variable pump main body is connected to a piston rod of the variable cylinder, and an oil outlet of the variable pump main body is communicated with a rod cavity of the variable cylinder; the electric proportional control assembly is communicated with an oil outlet of the variable pump main body; the oil outlet of the load sensitive valve is selectively communicated with the electric proportional control assembly and the variable pump main body, the oil outlet of the load sensitive valve is communicated with the rodless cavity of the variable cylinder, and one pilot end of the load sensitive valve is communicated with the oil outlet of the variable pump main body; the oil outlet of the electromagnetic reversing valve is communicated with the other pilot end of the load sensitive valve, and the oil outlet of the electromagnetic reversing valve is selectively communicated with the oil outlet of the variable pump main body and the load sensitive loop by controlling the on-off state of the electromagnetic reversing valve, so that the variable pump is switched between a load sensitive pump mode and a constant-pressure variable pump mode. The variable pump can switch the control mode of the pump, and has strong functionality.
Description
Technical Field
The invention relates to the technical field of hydraulic pressure, in particular to a variable pump and a hydraulic system.
Background
The constant pressure variable pump is used for outputting pressure oil at full displacement when the output pressure is smaller than a set constant pressure, namely, the constant output is realized, and when the pressure of the output oil reaches the set pressure, the flow of the pump is automatically regulated to ensure the constant pressure and meet the requirements of the system. The load sensitive pump is a hydraulic compensator that senses both system pressure and flow requirements and enables the plunger pump to respond correctly to changes in flow pressure requirements.
For the existing open variable pump system, the control function is single, when the open variable pump system is used as a constant-pressure variable pump, the sensitive use function of a load cannot be switched, the multifunctional requirement cannot be met, the open variable pump system is difficult to adapt to various complex working conditions, and the user experience feeling is poor.
Disclosure of Invention
The invention aims to provide a variable pump system and a hydraulic system, which can quickly switch the control mode of a pump according to actual use requirements and have stronger functionality.
In order to achieve the purpose, the invention adopts the following technical scheme:
a variable displacement pump comprising:
the variable pump comprises a variable pump main body and a variable cylinder, wherein a swash plate of the variable pump main body is connected to a piston rod of the variable cylinder, and an oil outlet of the variable pump main body is communicated with a rod cavity of the variable cylinder;
the electric proportional control assembly is communicated with an oil outlet of the variable pump main body;
the oil outlet of the load sensitive valve is selectively communicated with the electric proportional control assembly and the variable pump main body, the oil outlet of the load sensitive valve is communicated with the rodless cavity of the variable cylinder, and one pilot end of the load sensitive valve is communicated with the oil outlet of the variable pump main body;
and an oil outlet of the electromagnetic directional valve is communicated with the other pilot end of the load sensitive valve, and the oil outlet of the electromagnetic directional valve is selectively communicated with an oil outlet of the variable pump main body and the load sensitive loop by controlling the on-off of the electromagnetic directional valve, so that the electromagnetic directional valve is used for switching between a load sensitive pump mode and a constant-pressure variable pump mode.
Preferably, the electric proportional control assembly comprises an electric proportional directional valve, an oil outlet of the variable pump main body is communicated with the load sensitive valve through the electric proportional directional valve, and the electric proportional directional valve is configured to control a flow direction of hydraulic oil between a rod cavity and a rodless cavity of the variable cylinder, and is used for adjusting the opening degree of a swash plate of the variable pump main body so as to adjust the displacement of the variable pump main body.
Preferably, the electric proportional directional valve is a two-position three-way valve, a first interface of the electric proportional directional valve is communicated with an oil outlet of the variable pump main body, a second interface of the electric proportional directional valve is communicated with an oil tank, and a third interface of the electric proportional directional valve can be communicated with the rodless cavity of the variable cylinder through the load sensitive valve.
Preferably, the electric proportional control assembly further comprises a first electromagnetic valve, the first electromagnetic valve is respectively communicated with an oil tank and one control end of the electric proportional reversing valve, and the other control end of the electric proportional reversing valve is connected to the piston rod of the variable cylinder.
Preferably, the oil tank further comprises a second electromagnetic valve, and the second electromagnetic valve is respectively communicated with the oil outlet of the electromagnetic directional valve and the oil tank.
Preferably, the second electromagnetic valve is an overflow valve, and the pressure of the second electromagnetic valve is adjustable.
Preferably, the hydraulic control reversing valve is further included, the hydraulic control reversing valve can be selectively communicated with an oil outlet of the load sensitive valve and an oil outlet of the variable pump main body through an oil port of the load sensitive valve, an oil outlet of the hydraulic control reversing valve is communicated with the rodless cavity of the variable cylinder, and a control end of the electromagnetic reversing valve is communicated with an oil outlet of the variable pump main body.
Preferably, the variable pump further comprises a one-way control valve, and the one-way control valve is arranged between the variable pump main body and the electric proportional control assembly and is respectively communicated with the variable pump main body and the electric proportional control assembly.
Preferably, the one-way control valve is a shuttle valve, an oil outlet of the shuttle valve is communicated with the electric proportional control assembly, a first oil inlet of the shuttle valve is communicated with the variable pump main body, and the pressure of a second oil inlet of the shuttle valve is adjustable.
In order to achieve the above object, the present invention further provides a hydraulic system, which includes a load-sensitive circuit and the above variable displacement pump, wherein the electromagnetic directional valve of the variable displacement pump is selectively communicated with the load-sensitive circuit.
The invention has the beneficial effects that:
according to the variable displacement pump provided by the invention, when the electromagnetic directional valve is electrified, the right position of the electromagnetic directional valve works, so that the oil inlet of the electromagnetic directional valve is communicated with the load sensitive loop, and at the moment, two pilot ends of the load sensitive valve are respectively communicated with the load sensitive loop and the oil outlet of the variable displacement pump main body, so that the variable displacement pump is used for switching the working positions of the load sensitive valve and realizing the function of load sensitive control.
When the electromagnetic directional valve is powered off, the left position of the electromagnetic directional valve works, the oil outlet of the variable pump main body directly acts on one of the pilot ends of the load sensitive valve, the oil outlet of the variable pump main body is communicated with the oil inlet of the electromagnetic directional valve, hydraulic oil flowing out of the oil outlet of the variable pump main body enters the electromagnetic directional valve through the oil inlet of the electromagnetic directional valve, after throttling action, the hydraulic oil flows out of the oil outlet of the electromagnetic directional valve and acts on the other pilot end of the load sensitive valve, and pressure difference exists between the two pilot ends of the load sensitive valve due to the throttling action, so that the function of the constant-pressure variable pump is realized.
The variable displacement pump utilizes the electromagnetic directional valve to introduce or cut off the load sensitive signal of the load sensitive loop and control the load sensitive valve, can quickly switch the control mode of the pump according to the actual use requirement, and has strong functionality.
Meanwhile, the electric proportional control assembly is communicated with the oil outlet of the variable pump main body, and the oil inlet of the load sensitive valve can be communicated with the electric proportional control assembly, so that the electric proportional control assembly is arranged between the oil outlet of the variable pump main body and the oil inlet of the load sensitive valve, and can be electrically proportional controlled in a load sensitive pump mode and a constant-pressure variable pump mode so as to accurately adjust the displacement of the variable pump main body.
The invention also provides a hydraulic system which comprises a load sensitive loop and the variable pump, wherein the variable pump is selectively communicated with the load sensitive loop, so that the quick switching of different functions is realized, the operation efficiency is improved, and the functionality of the variable pump is increased.
Drawings
Fig. 1 is a hydraulic schematic of the variable displacement pump of the present invention.
In the figure:
100. a load-sensitive loop;
1. a variable pump body; 2. a variable cylinder; 3. an electrical proportional control component; 4. a load sensitive valve; 5. an electromagnetic directional valve; 6. a second solenoid valve; 7. a hydraulic control directional control valve; 8. a one-way control valve;
31. an electrically proportional directional valve; 32. a first solenoid valve.
Detailed Description
In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
The embodiment provides a variable pump, as shown in fig. 1, the variable pump includes a variable pump main body 1, a variable cylinder 2, an electric proportional control assembly 3, a load sensing valve 4 and an electromagnetic directional valve 5, the variable pump main body 1 is driven by an engine or a motor, a swash plate of the variable pump main body 1 is connected to a piston rod of the variable cylinder 2, the piston rod is connected to a piston, the piston is slidably disposed in a cylinder body of the variable cylinder 2, a spring is sleeved on the piston rod, two ends of the spring abut against an inner wall of the cylinder body and the piston, and the piston divides the cylinder body of the variable cylinder 2 into a rod cavity and a rodless cavity. An oil outlet (port P) of the variable pump body 1 is communicated with a rod cavity of the variable cylinder 2, and hydraulic oil can push the piston to slide relative to the cylinder body of the variable cylinder 2. An oil outlet (a port P) of the variable pump body 1 is communicated with the electric proportional control component 3, and the electric proportional control component 3 is used for electric proportional control.
An oil outlet of the load sensitive valve 4 is selectively communicated with an oil outlet of the electric proportional control assembly 3 and an oil outlet of the variable pump main body 1, an oil outlet of the load sensitive valve 4 is communicated with a rodless cavity of the variable cylinder 2, one pilot end of the load sensitive valve 4 is communicated with an oil outlet (port P) of the variable pump main body 1, and the other pilot end of the load sensitive valve 4 is communicated with an oil outlet (port P1) of the electromagnetic directional valve 5. Specifically, the load sensitive valve 4 is a two-position three-way valve, a first oil inlet of the load sensitive valve 4 is communicated with an oil outlet of the electric proportional reversing valve 31, a second oil inlet of the load sensitive valve 4 is communicated with an oil outlet (port P) of the variable pump main body 1, and an oil outlet of the load sensitive valve 4 is communicated with a rodless cavity of the variable cylinder 2.
The electromagnetic directional valve 5 is a two-position two-way valve, a first oil inlet of the electromagnetic directional valve 5 is communicated with an oil outlet (port P) of the variable pump body 1, a second oil inlet of the electromagnetic directional valve 5 is communicated with the load sensitive loop 100, and an oil outlet (port P1) of the electromagnetic directional valve 5 is communicated with the other pilot end of the load sensitive valve 4. By controlling the on-off of the electromagnetic directional valve 5, the oil outlet of the electromagnetic directional valve 5 is selectively communicated with the oil outlet (port P) of the variable pump main body 1 and the load sensitive loop 100, and is used for switching between a load sensitive pump mode and a constant-pressure variable pump mode.
In the variable displacement pump provided by the embodiment, when the electromagnetic directional valve 5 is powered on, the right position of the electromagnetic directional valve 5 works, so that the oil inlet of the electromagnetic directional valve 5 is communicated with the load sensitive loop 100, and at the moment, two pilot ends of the load sensitive valve 4 are respectively communicated with the load sensitive loop 100 and an oil outlet (port P) of the variable displacement pump main body 1, thereby realizing the function of load sensitive control.
When the electromagnetic directional valve 5 is powered off, the left position of the electromagnetic directional valve 5 works, the oil outlet (port P) of the variable pump main body 1 directly acts on one of the pilot ends of the load sensitive valve 4, the oil outlet (port P) of the variable pump main body 1 is communicated with the oil inlet of the electromagnetic directional valve 5, hydraulic oil flowing out of the oil outlet (port P) of the variable pump main body 1 enters the electromagnetic directional valve 5 through the oil inlet of the electromagnetic directional valve 5, after throttling action, the hydraulic oil flows out of the oil outlet (port P1) of the electromagnetic directional valve 5 and acts on the other pilot end of the load sensitive valve 4, and the two pilot ends of the load sensitive valve 4 have pressure difference due to the throttling action of the electromagnetic directional valve 5, so that the function of the constant-pressure variable pump is realized.
The variable displacement pump utilizes the electromagnetic directional valve 5 to introduce or cut off a load sensitive signal of the load sensitive loop 100 and control the load sensitive valve 4, can quickly switch the control mode of the pump according to the actual use requirement, and has strong functionality.
Meanwhile, the electric proportional control assembly 3 is communicated with the oil outlet (P port) of the variable pump main body 1, and the oil inlet of the load sensitive valve 4 can be communicated with the electric proportional control assembly 3, so that the electric proportional control assembly 3 is arranged between the oil outlet (P port) of the variable pump main body 1 and the oil inlet of the load sensitive valve 4, and can be electrically proportional controlled in a load sensitive pump mode and a constant-pressure variable pump mode to accurately adjust the displacement of the variable pump main body 1.
This variable pump still includes one-way control valve 8, and one-way control valve 8 sets up between variable pump main part 1 and electric proportional control subassembly 3 and is linked together rather than respectively, and one-way control valve 8 has played the effect of restriction hydraulic oil flow direction, makes the hydraulic oil that flows from the oil-out (P mouth) of variable pump main part 1 get into in the electric proportional control subassembly 3.
Specifically, the one-way control valve 8 is a shuttle valve, a first oil inlet of the shuttle valve is communicated with an oil outlet (port P) of the variable pump body 1, a second oil inlet (port E) of the shuttle valve is communicated with an external control end, and an oil outlet of the shuttle valve is communicated with the electric proportional control assembly 3. The first oil inlet and the second oil inlet of the shuttle valve can be communicated with the oil outlet of the shuttle valve, but the first oil inlet and the second oil inlet of the shuttle valve cannot be communicated with each other, hydraulic oil is input into any one of the first oil inlet and the second oil inlet of the shuttle valve, and hydraulic oil is output from the oil outlet of the shuttle valve. If the first oil inlet and the second oil inlet of the shuttle valve are both provided with hydraulic oil input, the hydraulic oil is firstly added into the oil inlet or the oil inlet on the high-pressure side is output through the oil outlet, and the other oil inlet is blocked. And only when the first oil inlet and the second oil inlet of the shuttle valve have no hydraulic oil input, the oil outlet of the shuttle valve has no hydraulic oil output.
If in the constant-pressure variable pump mode, the pilot end of the electromagnetic directional valve 5 is not acted by the load sensitive loop 100, and initially, the pressure of the oil outlet (port P) of the variable pump body 1 is small or even zero, and it is difficult to control the transposition of the load sensitive valve 4, for this reason, the pressure of the second oil inlet (port E) of the shuttle valve is adjustable, and in the constant-pressure variable pump mode, the external control end can set the pressure of the second oil inlet to be about 30bar, so that the oil outlet of the shuttle valve can output hydraulic oil.
Further, the electric proportional control assembly 3 includes an electric proportional directional valve 31, an oil outlet (port P) of the variable pump main body 1 is communicated with the load sensitive valve 4 through the electric proportional directional valve 31, and the electric proportional directional valve 31 is configured to control a flow direction of hydraulic oil between a rod chamber and a rodless chamber of the variable cylinder 2 for adjusting a swash plate of the variable pump main body 1 to adjust a displacement of the variable pump main body 1. Specifically, the electric proportional directional valve 31 is a two-position three-way valve, a first interface of the electric proportional directional valve 31 is communicated with an oil outlet (port P) of the variable pump body 1, a second interface of the electric proportional directional valve 31 is communicated with an oil tank, and a third interface of the electric proportional directional valve 31 is communicated with a rodless cavity of the variable cylinder 2 through the load sensitive valve 4.
When the working position of the electric proportional directional valve 31 is left, the first interface of the electric proportional directional valve 31 is opened, the second interface is closed, the hydraulic oil flowing out of the oil outlet of the variable pump main body 1 enters the first interface of the electric proportional directional valve 31 through the shuttle valve, flows into the load sensitive valve 4 from the third interface, and finally flows into the rodless cavity of the variable cylinder 2 to push the piston to compress the spring, and the piston drives the swash plate to swing through the piston rod, so that the displacement of the variable pump main body 1 is reduced.
When the working position of the electric proportional directional valve 31 is the right position, the first interface of the electric proportional directional valve 31 is closed, the second interface is opened, the hydraulic oil in the rodless cavity of the variable cylinder 2 flows into the electric proportional directional valve 31 through the third interface and flows back to the oil tank through the second interface, so that the pressure of the rodless cavity of the variable cylinder 2 is reduced, the volume of the rod cavity of the variable cylinder 2 is increased, the piston gradually moves to a large displacement position, the piston drives the swash plate to swing through the piston rod, and the displacement of the variable pump main body 1 is gradually increased.
In order to realize the transposition of the electric proportional directional valve 31, the electric proportional control assembly 3 further comprises a first electromagnetic valve 32, the first electromagnetic valve 32 is respectively communicated with the oil tank and one control end of the electric proportional directional valve 31, and the other control end of the electric proportional directional valve 31 is connected to the piston rod of the variable cylinder 2. When the first electromagnetic valve 32 is powered off, the piston rod acts on the other control end of the electric proportional directional valve 31 through the connecting rod, so that the working position of the electric proportional directional valve 31 is a left position; when the first electromagnetic valve 32 is energized, the hydraulic oil flowing out of the first electromagnetic valve 32 acts on one control end of the electric proportional directional valve 31, so that the operating position of the electric proportional directional valve 31 is the right position.
The variable displacement pump also includes a pilot operated directional control valve 7. An oil inlet of the hydraulic control reversing valve 7 is selectively communicated with an oil outlet of the load sensitive valve 4 and an oil outlet (P port) of the variable pump main body 1, an oil outlet of the hydraulic control reversing valve 7 is communicated with a rodless cavity of the variable cylinder 2, and a control end of the electromagnetic reversing valve 5 is communicated with an oil outlet (P port) of the variable pump main body 1.
Specifically, the hydraulic control directional control valve 7 is a two-position three-way valve, a first oil inlet of the hydraulic control directional control valve 7 is communicated with an oil outlet of the load sensitive valve 4, a second oil inlet of the hydraulic control directional control valve 7 is communicated with an oil outlet (port P) of the variable pump main body 1, and an oil outlet of the hydraulic control directional control valve 7 is communicated with a rodless cavity of the variable cylinder 2.
The spring of the hydraulic control reversing valve 7 can be set to be the highest cutting-off pressure, the control end of the hydraulic control reversing valve 7 is communicated with the oil outlet (P port) of the variable pump main body 1, when the pressure of the oil outlet (P port) of the variable pump main body 1 is smaller than the highest cutting-off pressure which can be set by the spring, the working position of the hydraulic control reversing valve 7 is the upper position, the first oil inlet of the hydraulic control reversing valve 7 is opened, the second oil inlet is closed, and therefore hydraulic oil flowing out of the load sensitive valve 4 enters the hydraulic control reversing valve 7 through the first oil inlet and flows into the rodless cavity of the variable cylinder 2 through the oil outlet of the hydraulic control reversing valve 7.
When the pressure of the oil outlet (port P) of the variable pump main body 1 is greater than the highest cutting-off pressure which can be set by the spring, the working position of the hydraulic control reversing valve 7 is the lower position, the first oil inlet of the hydraulic control reversing valve 7 is closed, the second oil inlet is opened, and the hydraulic oil flowing out of the oil outlet (port P) of the variable pump main body 1 directly enters the second oil inlet of the hydraulic control reversing valve 7 after passing through the shuttle valve and flows into the rodless cavity of the variable cylinder 2 through the oil outlet of the hydraulic control reversing valve 7. In this way, the pressure shut-off function can be achieved manually even if the load sensitive valve 4 fails.
It is understood that, as shown in fig. 1, a variable pump body 1 and a variable cylinder 2 are provided in a lower virtual frame, which represents a main structure of the variable pump; an electric proportional directional valve 31 and a first electromagnetic valve 32 are arranged in the virtual frame on the left side, the virtual frame represents an electric control part, a load sensitive valve 4 and a hydraulic control directional valve 7 are arranged in the virtual frame on the right side, and the virtual frame represents a load sensitive control part. These three virtual frames can be regarded as the self-contained structure of the variable displacement pump body 1, forming an integrated pump.
In order to realize the remote control of the variable displacement pump, the variable displacement pump further comprises a second electromagnetic valve 6, and the second electromagnetic valve 6 is respectively communicated with an oil outlet (P1 port) of the electromagnetic directional valve 5 and an oil tank. The second solenoid valve 6 is disposed outside the three dotted frames, representing the outside of the integrated pump. Wherein, the second electromagnetic valve 6 is an overflow valve, and the pressure of the second electromagnetic valve 6 is adjustable.
The pressure of the oil outlet (port P1) of the electromagnetic directional valve 5 is set through the second electromagnetic valve 6, when the pressure difference between the oil outlet (port P1) of the electromagnetic directional valve 5 and the oil outlet (port P) of the variable pump body 1 reaches the spring set pressure of the load sensitive valve 4, the lower position of the load sensitive valve 4 works, hydraulic oil from the oil outlet (port P) of the variable pump body 1 enters the rodless cavity of the variable cylinder 2 through the load sensitive valve 4, the piston gradually moves to a small displacement position, and the displacement of the variable pump body 1 gradually decreases to achieve the purpose of pressure cut-off. In addition, the pressure of the second electromagnetic valve 6 can be adjusted by adjusting the set current, so that remote pressure adjustment is realized.
The working process of the variable pump provided by the embodiment is as follows:
load sensitive pump mode
The electromagnetic directional valve 5 is electrified, the right position of the electromagnetic directional valve 5 works, and an oil inlet of the electromagnetic directional valve 5 is communicated with the load sensitive loop 100 to introduce a load sensitive signal.
The engine or the motor drives the variable pump main body 1, when the engine is flamed out or the motor does not rotate, the swash plate of the variable pump main body 1 is pushed to the initial maximum displacement position under the action of the piston rod of the variable cylinder 2 and the spring, and the piston is located at the rightmost end of the cylinder body of the variable cylinder 2 at the moment. When an engine or a motor is started, hydraulic oil flowing out of an oil outlet (port P) of the variable displacement pump main body 1 passes through the shuttle valve and is divided into three branches, the first branch is communicated with a first port of the electric proportional reversing valve 31, the second branch is communicated with a second oil inlet of the load sensitive valve 4, and the third branch is communicated with a second oil inlet of the hydraulic control reversing valve 7.
The first electromagnetic valve 32 is powered off, the right control end of the electric proportional directional valve 31 has no pressure, the left control end of the electric proportional directional valve 31 is connected to the piston rod through a connecting rod, under the driving action of the piston rod, the left control end of the electric proportional directional valve 31 is greater than the pressure of the right control end of the electric proportional directional valve 31, the working position of the electric proportional directional valve 31 is the left position, hydraulic oil of the first branch enters a rodless cavity of the variable cylinder 2 through the electric proportional directional valve 31, the load sensitive valve 4 and the hydraulic control directional valve 7, the hydraulic oil pushes the piston compression spring, the variable pump main body 1 is enabled to be at the minimum displacement, and standby pressure is maintained.
When the first electromagnetic valve 32 is powered on, hydraulic oil flowing out of the first electromagnetic valve 32 acts on one control end of the electric proportional directional valve 31, so that the working position of the electric proportional directional valve 31 is the right position, the first interface of the electric proportional directional valve 31 is closed, the second interface is opened, hydraulic oil in the rodless cavity of the variable cylinder 2 flows into the electric proportional directional valve 31 through the third interface and flows back into the oil tank through the second interface, the pressure of the rodless cavity of the variable cylinder 2 is reduced, the volume of the rod cavity of the variable cylinder 2 is increased, the piston gradually moves to a large displacement position, the piston drives the swash plate to swing through the piston rod, and the displacement of the variable pump main body 1 is gradually increased.
When the pressure of the oil outlet (port P1) of the electromagnetic directional valve 5 is set by the second electromagnetic valve 6, that is, the pressure of the load-sensitive signal is kept at a set value, and when the pressure of the oil outlet (port P) of the variable pump body 1 is greater than the pressure of the load-sensitive circuit 100, or the pressure difference between the oil outlet (port P1) of the electromagnetic directional valve 5 and the oil outlet (port P) of the variable pump body 1 reaches the spring set pressure of the load-sensitive valve 4, that is, the pilot pressure at the lower end of the load-sensitive valve 4 is greater than the pilot pressure at the upper end of the load-sensitive valve 4, the working position of the load-sensitive valve 4 is at a lower position, so that the second branch is communicated with the second liquid inlet of the load-sensitive valve 4 and enters the rodless cavity of the variable cylinder 2 through the hydraulic directional valve 7, and the piston gradually moves leftward, that is gradually close to.
When the pressure of the oil outlet (port P) of the variable displacement pump main body 1 is greater than the highest cutoff pressure of the spring of the hydraulic control reversing valve 7, the working position of the hydraulic control reversing valve 7 is the lower position, the first oil inlet of the hydraulic control reversing valve 7 is closed, the second oil inlet is opened, the hydraulic oil of the third branch directly enters the second oil inlet of the hydraulic control reversing valve 7, and flows into the rodless cavity of the variable cylinder 2 through the oil outlet of the hydraulic control reversing valve 7. In this way, the pressure shut-off function can be achieved manually even if the load sensitive valve 4 fails. Therefore, the load-sensitive pump mode realizes the functions of electric proportional control, load-sensitive control and remote constant-voltage control.
Constant pressure pump mode
The electromagnetic directional valve 5 is powered off, the left position of the electromagnetic directional valve 5 works to cut off a load sensitive LS signal, an oil inlet of the electromagnetic directional valve 5 is communicated with an oil outlet (P port) of the variable pump main body 1, and the pressure of a second oil inlet (E port) of the shuttle valve, which can be set at the external control end, is about 30bar, so that the oil outlet of the shuttle valve can output hydraulic oil.
The engine or the motor drives the variable pump main body 1, and when the engine is shut down or the motor does not rotate, the pressure of the rod cavity of the variable cylinder 2 is controlled by the pressure of the second oil inlet (E port) of the shuttle valve.
The first electromagnetic valve 32 is powered off, the right control end of the electric proportional directional valve 31 has no pressure, the left control end of the electric proportional directional valve 31 is connected to the piston rod through a connecting rod, under the driving action of the piston rod, the left control end of the electric proportional directional valve 31 is greater than the pressure of the right control end of the electric proportional directional valve 31, the working position of the electric proportional directional valve 31 is the left position, hydraulic oil flowing out of an oil outlet (P port) of the variable pump main body 1 enters the electric proportional directional valve 31, the load sensitive valve 4 and the hydraulic control directional valve 7 through a shuttle valve and enters a rodless cavity of the variable cylinder 2, the hydraulic oil pushes a piston compression spring, the variable pump main body 1 is changed into the minimum displacement, and the standby pressure is maintained.
When the first electromagnetic valve 32 is powered on, hydraulic oil flowing out of the first electromagnetic valve 32 acts on one control end of the electric proportional directional valve 31, so that the working position of the electric proportional directional valve 31 is the right position, the first interface of the electric proportional directional valve 31 is closed, the second interface is opened, hydraulic oil in the rodless cavity of the variable cylinder 2 flows into the electric proportional directional valve 31 through the third interface and flows back into the oil tank through the second interface, the pressure of the rodless cavity of the variable cylinder 2 is reduced, the volume of the rod cavity of the variable cylinder 2 is increased, the piston gradually moves to a large displacement position, the piston drives the swash plate to swing through the piston rod, and the displacement of the variable pump main body 1 is gradually increased.
The pressure at the oil outlet (port P1) of the electromagnetic directional valve 5 is set by the second electromagnetic valve 6, that is, the pressure at the oil outlet (port P1) of the electromagnetic directional valve 5 is kept at a set value, that is, the pressure of the hydraulic oil flowing out of the variable displacement pump main body 1 after being throttled by the electromagnetic directional valve 5 is a set value. When the pressure of an oil outlet (port P) of the variable pump main body 1 is greater than the pressure of an oil outlet (port P1) of the electromagnetic directional valve 5, or the pressure difference between the oil outlet (port P1) of the electromagnetic directional valve 5 and the oil outlet (port P) of the variable pump main body 1 reaches the spring set pressure of the load sensitive valve 4, namely the pilot pressure at the lower end of the load sensitive valve 4 is greater than the pilot pressure at the upper end of the load sensitive valve 4, the working position of the load sensitive valve 4 is lower, so that the second branch is communicated with the second oil inlet of the load sensitive valve 4 and enters a rodless cavity of the variable cylinder 2 through the hydraulic directional valve 7, the piston gradually moves leftwards, namely gradually approaches a small displacement position, and the displacement of the variable pump main body 1 is gradually reduced.
When the pressure of the oil outlet (port P) of the variable displacement pump main body 1 is greater than the highest cutoff pressure of the spring of the hydraulic control reversing valve 7, the working position of the hydraulic control reversing valve 7 is the lower position, the first oil inlet of the hydraulic control reversing valve 7 is closed, the second oil inlet is opened, the hydraulic oil of the third branch directly enters the second oil inlet of the hydraulic control reversing valve 7, and flows into the rodless cavity of the variable cylinder 2 through the oil outlet of the hydraulic control reversing valve 7. In this way, the pressure shut-off function can be achieved manually even if the load sensitive valve 4 fails. Therefore, the constant pressure pump mode realizes the functions of electric proportional control and remote constant pressure control.
The embodiment also provides a hydraulic system, which comprises a load sensitive loop and the variable pump, wherein the electromagnetic directional valve of the variable pump is selectively communicated with the load sensitive loop, so that different functions can be rapidly switched, the operation efficiency is improved, and the functionality of the variable pump is improved.
In the description herein, it is to be understood that the terms "upper", "lower", "right", and the like are based on the orientations and positional relationships shown in the drawings and are used for convenience in description and simplicity in operation, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be constructed in a particular operation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive purposes and are not intended to have any special meaning.
In the description herein, references to the description of "an embodiment," "an example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.
In addition, the foregoing is only the preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A variable displacement pump, comprising:
the variable pump comprises a variable pump main body (1) and a variable cylinder (2), wherein a swash plate of the variable pump main body (1) is connected to a piston rod of the variable cylinder (2), and an oil outlet of the variable pump main body (1) is communicated with a rod cavity of the variable cylinder (2);
the electric proportional control assembly (3) is communicated with an oil outlet of the variable pump main body (1);
the oil outlet of the load sensitive valve (4) is selectively communicated with the oil outlet of the electric proportional control assembly (3) and the oil outlet of the variable pump main body (1), the oil outlet of the load sensitive valve (4) is communicated with the rodless cavity of the variable cylinder (2), and one pilot end of the load sensitive valve (4) is communicated with the oil outlet of the variable pump main body (1);
the oil outlet of the electromagnetic directional valve (5) is communicated with the other pilot end of the load sensitive valve (4), the oil outlet of the electromagnetic directional valve (5) is selectively communicated with the oil outlet of the variable pump main body (1) and the load sensitive loop (100) by controlling the on-off of the electromagnetic directional valve (5), and the electromagnetic directional valve is used for switching between a load sensitive pump mode and a constant-pressure variable pump mode.
2. The variable displacement pump according to claim 1, wherein the electro-proportional control assembly (3) comprises an electro-proportional directional valve (31), an oil outlet of the variable displacement pump body (1) is communicated with the load sensitive valve (4) through the electro-proportional directional valve (31), and the electro-proportional directional valve (31) is configured to control a flow direction of hydraulic oil between a rod chamber and a rodless chamber of the variable cylinder (2) for adjusting a swash plate opening degree of the variable displacement pump body (1) to adjust a displacement of the variable displacement pump body (1).
3. Variable pump according to claim 2, characterized in that the electro-proportional directional valve (31) is a two-position three-way valve, a first port of the electro-proportional directional valve (31) is communicated with the oil outlet of the variable pump body (1), a second port of the electro-proportional directional valve (31) is communicated with an oil tank, and a third port of the electro-proportional directional valve (31) can be communicated with the rodless cavity of the variable cylinder (2) through the load sensitive valve (4).
4. A variable displacement pump according to claim 2 or 3, wherein the electro-proportional control assembly (3) further comprises a first solenoid valve (32), the first solenoid valve (32) being in communication with a tank and one control end of the electro-proportional reversing valve (31), respectively, the other control end of the electro-proportional reversing valve (31) being connected to the piston rod of the variable displacement cylinder (2).
5. The variable displacement pump according to claim 1, further comprising a second electromagnetic valve (6), wherein the second electromagnetic valve (6) is respectively communicated with an oil outlet of the electromagnetic directional valve (5) and an oil tank.
6. Variable displacement pump according to claim 5, characterized in that the second solenoid valve (6) is a relief valve, the pressure of the second solenoid valve (6) being adjustable.
7. The variable pump according to claim 1, further comprising a hydraulic control reversing valve (7), wherein an oil outlet of the hydraulic control reversing valve (7) is selectively communicated with an oil outlet of the load sensitive valve (4) and an oil outlet of the variable pump main body (1), an oil outlet of the hydraulic control reversing valve (7) is communicated with the rodless cavity of the variable cylinder (2), and a control end of the electromagnetic reversing valve (5) is communicated with an oil outlet of the variable pump main body (1).
8. Variable displacement pump according to claim 1, further comprising a one-way control valve (8), the one-way control valve (8) being disposed between the variable displacement pump body (1) and the electric proportional control assembly (3) and communicating with the variable displacement pump body (1) and the electric proportional control assembly (3), respectively.
9. Variable displacement pump according to claim 8, characterized in that the one-way control valve (8) is a shuttle valve, the oil outlet of which is connected to the electro-proportional control unit (3), the first oil inlet of which is connected to the variable displacement pump body (1), and the second oil inlet of which is pressure adjustable.
10. A hydraulic system, characterized by comprising a load-sensitive circuit (100) and a variable displacement pump according to any one of claims 1 to 9, the electromagnetic directional valve (5) of which is in selective communication with the load-sensitive circuit (100).
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| CN202011063182.9A CN112096671A (en) | 2020-09-30 | 2020-09-30 | Variable pump and hydraulic system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011063182.9A CN112096671A (en) | 2020-09-30 | 2020-09-30 | Variable pump and hydraulic system |
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| CN112096671A true CN112096671A (en) | 2020-12-18 |
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| CN202011063182.9A Pending CN112096671A (en) | 2020-09-30 | 2020-09-30 | Variable pump and hydraulic system |
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Application publication date: 20201218 |