CN110848111B - Plunger variable pump integrated control system - Google Patents
Plunger variable pump integrated control system Download PDFInfo
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- CN110848111B CN110848111B CN201911184508.0A CN201911184508A CN110848111B CN 110848111 B CN110848111 B CN 110848111B CN 201911184508 A CN201911184508 A CN 201911184508A CN 110848111 B CN110848111 B CN 110848111B
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- 230000009699 differential effect Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
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- 230000009471 action Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000003993 interaction Effects 0.000 description 2
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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
- F04B13/00—Pumps specially modified to deliver fixed or variable measured quantities
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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
- F04B49/06—Control using electricity
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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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- 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
- F04B51/00—Testing machines, pumps, or pumping installations
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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
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
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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
- F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
- F04B53/10—Valves; Arrangement of valves
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Abstract
The invention discloses a plunger variable pump integrated control system, which is installed in combination with a plunger variable pump, wherein the plunger variable pump comprises a swash plate, the swash plate is installed in the plunger variable pump, the inclination angle of the swash plate determines the displacement of the plunger variable pump, and the plunger variable pump integrated control system comprises a large connecting rod, a small connecting rod, a lower variable cylinder, an upper variable cylinder, an integrated control assembly and a control oil way; the large connecting rod and the small connecting rod are respectively connected with two ends of the swash plate, the large connecting rod is used as a piston of the lower variable cylinder and is connected with the lower variable cylinder, and the small connecting rod is used as a piston of the upper variable cylinder and is connected with the upper variable cylinder; the upper variable cylinder is normally communicated with high-pressure oil of an oil outlet of the plunger pump or control oil of an external control port; the integrated control assembly is connected with an oil outlet of the plunger pump through an oil way and is connected with the small connecting rod; and the lower variable cylinder is connected with the integrated control assembly through the control oil way.
Description
Technical Field
The invention relates to the technical field of hydraulic pump control systems, in particular to an integrated control system of a plunger variable pump.
Background
In a hydraulic control system of a construction machine, integrated control of electric proportional positive displacement control and pressure cut-off control is a common variable mode of a plunger variable displacement pump. The electric proportional positive displacement control refers to a control mode of automatically adjusting the displacement increase of the plunger variable displacement pump by increasing input control current. The electric proportional positive displacement control is adopted, the control programming of a host system is favorably realized, signals are collected and analyzed through the pressure sensor and the flow sensor, current is output to the plunger variable pump through program control, the displacement of the plunger variable pump is quickly adjusted, the working condition requirement of the host is met, the control diversification, the intellectualization and the digitization are realized, and meanwhile, the operation convenience of the host system can be improved. By applying electric proportional positive displacement control in the main machine control, the power of the engine can be fully utilized. By changing the control current, the flow rate output by the main pump when the main machine performs a plurality of actions can be made to correspond to the load pressure. When the main machine works, the system program can automatically adjust the control current of the plunger variable pump according to the load pressure, change the output flow, and control and change the movement speed of actions of hoisting, stretching and retracting of the oil cylinder, getting on and turning and the like of the main machine.
The pressure cut-off control refers to a control mode of automatically adjusting the pump displacement to a minimum set value when the plunger variable displacement pump reaches a certain load pressure. And by adopting pressure cut-off control, the protection function of the plunger variable pump and a hydraulic system can be realized. When a certain hydraulic component in the main circuit is in failure or is overloaded, the pressure of the whole hydraulic system can be too high, and if the pressure exceeds the rated bearing pressure of the hydraulic component, the hydraulic component can be damaged, and the safety of operators can be endangered. The pressure cutoff control uses a pressure cutoff control valve that sets the maximum pressure of the pump. When the system pressure reaches the maximum pressure, the pressure cutoff control valve opens so that the displacement of the plunger variable displacement pump is reduced to a set minimum displacement (usually set minimum displacement close to 0), the minimum displacement maintains the system minimum flow requirement at the maximum pressure, and the system pressure stops increasing. The host system cannot work normally when the displacement of the plunger variable displacement pump is reduced to the minimum displacement.
In order to realize the electric proportional positive displacement control, a proportional electromagnet needs to be used, if the proportional electromagnet fails suddenly or a current input device of a host system fails, a plunger variable displacement pump can be changed to the minimum displacement immediately, the pressure of a hydraulic system can drop instantly, the host stops acting immediately, and the sudden stop of the operation of hoisting and concrete pumping machinery and the like is very dangerous. The problem is solved by setting a larger minimum displacement, and although the output flow of the plunger variable displacement pump can be ensured when the proportional electromagnet suddenly fails, in the pressure cut-off control process, the pressure of a host system is higher than the highest pressure set by the pressure cut-off control and can be continuously increased, and the safety protection function of the pressure cut-off control basically fails.
Disclosure of Invention
In view of the above, the present invention provides an integrated control system for a plunger variable displacement pump, which integrates electric proportional positive displacement control and pressure cut-off control functions, and when a proportional electromagnet in the integrated control system for the plunger variable displacement pump fails, the plunger variable displacement pump can keep working, and the pressure cut-off control is still effective.
In order to achieve the above object, the present invention provides an integrated control system for a plunger variable pump, which is installed in combination with the plunger variable pump, wherein the plunger variable pump comprises a swash plate, the swash plate is installed inside the plunger variable pump, the inclination angle of the swash plate determines the displacement of the plunger variable pump, the plunger variable pump is provided with a plunger pump oil inlet and a plunger pump oil outlet, and the integrated control system for the plunger variable pump comprises a large connecting rod, a small connecting rod, a lower variable cylinder, an upper variable cylinder, an integrated control assembly and a control oil path; the large connecting rod and the small connecting rod are respectively connected with two ends of the swash plate, the large connecting rod is used as a piston of the lower variable cylinder and is connected with the lower variable cylinder, and the small connecting rod is used as a piston of the upper variable cylinder and is connected with the upper variable cylinder; the upper variable cylinder is normally communicated with high-pressure oil of an oil outlet of the plunger pump or control oil of an external control port; the integrated control assembly is connected with an oil outlet of the plunger pump through an oil way, the integrated control assembly is connected with an oil return oil way, and the integrated control assembly is connected with the small connecting rod; and the lower variable cylinder is connected with the integrated control assembly through the control oil way.
Preferably, the integrated control assembly comprises a valve body, a feedback rod, and an electric proportional control valve, a hydraulic control valve and a pressure cut-off control valve which are arranged in the valve body; one end of the feedback rod is connected with the small connecting rod, and the other end of the feedback rod is inserted into the valve body and is connected with the electric proportional control valve through a feedback spring; one end of the electric proportional control valve, which is far away from the feedback rod, is provided with a proportional electromagnet, and the electric proportional control valve is provided with an electric proportional control adjusting spring; the oil return oil way is connected with the electric proportional control valve, the hydraulic limiting valve is arranged in parallel with the electric proportional control valve, and the feedback rod is positioned between the electric proportional control valve and the hydraulic control valve; the pressure cutoff control valve has an adjusting spring, and the opening pressure of the pressure cutoff control valve is set by adjusting the adjusting spring of the pressure cutoff control valve.
Preferably, a hydraulic limit adjusting mechanism is installed at one end, far away from the feedback rod, of the hydraulic control valve, and the set minimum displacement of the plunger variable displacement pump is adjusted by adjusting the hydraulic limit adjusting mechanism.
Preferably, the hydraulic limiting valve adjusting mechanism comprises a valve sleeve and a locking nut, the valve sleeve penetrates into the valve body and is connected with the valve body, the locking nut surrounds the valve sleeve and is connected with the valve sleeve, and the valve sleeve and the hydraulic limiting valve are coaxially arranged and contact with the hydraulic limiting valve.
Preferably, the valve sleeve is provided with an external thread, the joint of the valve body and the valve sleeve is provided with an internal thread, the valve sleeve is in threaded connection with the valve body, and the valve sleeve is of an external hexagonal structure.
Preferably, the upper end of the pressure cut-off control valve is connected with the oil outlet of the plunger pump through an oil path, and the upper end of the pressure cut-off control valve is connected with the lower variable cylinder through the control oil path; the lower end of the pressure cut-off control valve is connected with the lower end of the electric proportional control valve through an oil way; the upper end of the electric proportional control valve is connected with the lower end of the hydraulic limiting valve through an oil way; the upper end of the hydraulic limiting valve is connected with the lower end of the pressure cut-off control valve through an oil way; the electric proportional control valve, the hydraulic limiting valve and the pressure cut-off control valve are all provided with a left position and a right position, and the electric proportional control valve, the hydraulic limiting valve and the pressure cut-off control valve change the communication state of oil passages at the upper end and the lower end of the electric proportional control valve through the switching of the left position and the right position.
Preferably, when the electric proportional control valve is in a right position, the hydraulic limiting valve is in a right position, and the pressure cut-off control valve is in a left position, high-pressure oil of an oil outlet of the plunger pump or control oil of an external control port flows into the lower variable cylinder through the integrated control assembly and the control oil path.
Preferably, when the electric proportional control valve is in the right position, the hydraulic limit valve is in the left position, and the pressure cut-off control valve is in the left position, the hydraulic limit valve blocks oil flowing to the lower variable cylinder.
Preferably, when the electro-proportional control valve is in the left position and the pressure cutoff control valve is in the left position, oil in the lower variable cylinder flows back.
Preferably, when the pressure cut-off control valve is in the right position, the high-pressure oil at the oil outlet of the plunger pump enters the lower variable cylinder through the pressure cut-off control valve and the control oil path.
Compared with the prior art, the integrated control system of the plunger variable pump disclosed by the invention has the advantages that: by adopting the plunger variable pump integrated control system, the displacement of the plunger variable pump can still ensure the action of a host under the condition that a proportional electromagnet fails or a current input device of the host system fails, the sudden pressure drop is prevented, the safety protection effect of pressure cut-off control can be ensured to be still effective, and the safety of use is improved while the protection functions of the plunger variable pump and a hydraulic system are not influenced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic diagram of an integrated control system of a plunger variable displacement pump according to the present invention.
Fig. 2 is a schematic structural diagram of an integrated control system of a plunger variable displacement pump according to the present invention.
Fig. 3 is a schematic structural diagram of a hydraulic limit valve adjusting mechanism of an integrated control system of a plunger variable displacement pump according to the present invention.
Fig. 4 is a pressure-displacement curve diagram of the integrated control system of the plunger variable displacement pump in the case of the failure of the proportional electromagnet.
Fig. 5 is a graph showing the pressure-displacement curve when the proportional solenoid fails using the prior art plunger variable displacement pump integrated control system.
Detailed Description
As shown in fig. 1 and 2, an integrated control system for a plunger variable displacement pump according to the present invention is installed in combination with a plunger variable displacement pump 1, wherein the plunger variable displacement pump 1 includes a swash plate 10, the swash plate 10 is installed inside the plunger variable displacement pump 1, an inclination angle of the swash plate determines a displacement of the plunger variable displacement pump 1, and the plunger variable displacement pump 1 has a plunger pump oil inlet 101 and a plunger pump oil outlet 102. The plunger variable pump integrated control system comprises a large connecting rod 111, a small connecting rod 112, a lower variable cylinder 11, an upper variable cylinder 12, an integrated control assembly 2 and a control oil circuit 30. The large connecting rod 111 and the small connecting rod 112 are hinged to both ends of the swash plate 10, respectively. The large connecting rod 111 is connected to the lower variable cylinder 11 as a piston of the lower variable cylinder 11, and the small connecting rod 112 is connected to the upper variable cylinder 12 as a piston of the upper variable cylinder 12. Under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, the inclination angle of the swash plate 10 is changed, thereby changing the displacement of the plunger variable displacement pump 1. The upper variable cylinder 12 is normally open to the high pressure oil at the plunger pump outlet 102 or to the control oil at the external control port. The integrated control assembly 2 is connected with the upper variable cylinder 12 and the plunger pump oil outlet 102 through oil passages, and the integrated control assembly 2 is connected with the small connecting rod 112. The lower variable cylinder 11 is connected with the integrated control assembly 2 through the control oil path 30. The integrated control assembly 2 is further connected with an oil return path 301.
Specifically, the integrated control assembly 2 includes a valve body 20, a feedback rod 21, an electro-proportional control valve 22, a hydraulic control valve 23, and a pressure cutoff control valve 24. The electric proportional control valve 22, the hydraulic control valve 23, and the pressure cutoff control valve 24 are all installed inside the valve body 20. One end of the feedback rod 21 is connected with the small connecting rod 112, the other end of the feedback rod is inserted into the valve body 20 and connected with the electric proportional control valve 22, the feedback rod 21 is driven by the small connecting rod 112 to move, and the small connecting rod 112 senses the displacement change of the plunger variable displacement pump 1 in real time. A proportional electromagnet 221 is installed at one end of the electric proportional control valve 22 far away from the feedback rod 21, one end of the electric proportional control valve 22 facing the feedback rod 21 is connected with the feedback rod 21 through a feedback spring 222, and the electric proportional control valve 22 is provided with an electric proportional control adjusting spring. The oil return path 301 is connected to the electric proportional control valve 22. The hydraulic limit valve 23 is arranged in parallel with the electric proportional control valve 22, the feedback rod 21 is positioned between the electric proportional control valve 22 and the hydraulic control valve 23, and the feedback rod 21 moves towards the hydraulic control valve 23 to push the hydraulic control valve 23 and change the state of the hydraulic control valve 23. A hydraulic limit adjusting mechanism 231 is installed at one end of the hydraulic control valve 23 far away from the feedback rod 21, and the position of the hydraulic control valve 23 in the valve body 20 can be adjusted by adjusting the hydraulic limit adjusting mechanism 231, so that the minimum displacement of the plunger variable displacement pump 1 is limited. The pressure cutoff control valve 24 has an adjusting spring, and the opening pressure of the pressure cutoff control valve 24 can be set by adjusting the adjusting spring of the pressure cutoff control valve 24, when the pressure at the plunger pump oil outlet 102 reaches the opening pressure, the pressure cutoff control valve 24 opens, and the plunger variable displacement pump 1 varies to zero displacement.
Referring to fig. 1, the upper end of the pressure cut-off control valve 24 is connected to the plunger pump oil outlet 102 through an oil passage, and the upper end of the pressure cut-off control valve 24 is connected to the lower variable cylinder 11 through the control oil passage 30; the lower end of the pressure cut-off control valve 24 is connected with the lower end of the electric proportional control valve 22 through an oil path; the upper end of the electric proportional control valve 22 is connected with the lower end of the hydraulic limiting valve 23 through an oil way; the upper end of the hydraulic limit valve 23 is connected to the lower end of the pressure cutoff control valve 24 through an oil passage. The electric proportional control valve 22, the hydraulic limit valve 23 and the pressure cut-off control valve 24 all have a left position and a right position. The electric proportional control valve 22, the hydraulic limiting valve 23 and the pressure cutoff control valve 24 can change the oil passage communication state of the upper end and the lower end thereof by switching between the left position and the right position. By changing the left and right position combination of the electric proportional control valve 22, the hydraulic limit valve 23 and the pressure cut-off control valve 24, the flow direction of an oil path in the integrated control assembly 2 can be changed, so that the displacement control and cut-off control functions are realized.
Specifically, when the electric proportional control valve 22 is in the right position, the hydraulic limit valve 23 is in the right position, and the pressure cut-off control valve 24 is in the left position, the high-pressure oil at the plunger pump oil outlet 102 or the control oil at the external control port flows into the lower variable cylinder 11 through the integrated control assembly 2 and the control oil path 30. When the electric proportional control valve 22 is in the right position, the hydraulic limit valve 23 is in the left position, and the pressure cut-off control valve 24 is in the left position, the oil flowing to the lower variable cylinder 11 is blocked by the hydraulic limit valve 23. When the electric proportional control valve 22 is in the left position and the pressure cut-off control valve 24 is in the left position, oil in the lower variable cylinder 11 flows back to realize unloading. When the pressure cut-off control valve 24 is in the right position, the high-pressure oil at the plunger pump oil outlet 102 directly enters the lower variable cylinder 11 through the pressure cut-off control valve 24 and the control oil path 30.
In order to more clearly illustrate the technical solution of the present invention, the following description is made for different states of the plunger variable pump integrated control system. The minimum displacement of the plunger variable displacement pump 1 is set to be Y, and the corresponding control current is set to be X. The acting force of the feedback spring 222 is Fs, the acting force of the electric proportional control adjusting spring is Ft, the thrust of the proportional electromagnet 221 is F, and the Fs and Ft are opposite to the F direction. When the control current is X, the thrust of the proportional electromagnet 221 is Fx, and Fx ═ Fs + Ft.
In order to realize that the displacement of the plunger variable displacement pump 1 is the set minimum flow Y, the control input current is less than or equal to X, at the moment, the thrust F of the proportional electromagnet 221 is less than the resultant force of Fs and Ft, the electric proportional control valve 22 is in the right position, and the hydraulic limiting valve 23 is in the right position; the high-pressure oil at the oil outlet 102 of the plunger pump or the control oil at the external control port flows into the lower variable cylinder 11 through the integrated control assembly 2 and the control oil path 30; under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, the displacement of the plunger variable pump 1 is reduced, the small connecting rod 112 drives the feedback rod 21 to move towards the hydraulic limit valve 23 until the feedback rod 21 pushes the hydraulic limit valve 23, so that the hydraulic limit valve 23 is switched to the left position, the oil flowing to the lower variable cylinder 11 is blocked by the hydraulic limit valve 23, and the displacement of the plunger variable pump 1 is the set minimum flow Y; because the oil flowing to the lower variable cylinder 11 is blocked by the hydraulic limit valve 23, the lower variable cylinder 11 leaks, and under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, the displacement of the plunger variable pump 1 is increased, the small connecting rod 112 drives the feedback rod 21 to move in the direction away from the hydraulic limit valve 23, the hydraulic limit valve 23 returns to the right position, the oil enters the lower variable cylinder 11 again, and the displacement of the plunger variable pump 1 is reduced. The above processes are performed repeatedly, so that the plunger variable displacement pump 1 keeps the minimum set displacement Y under the control of the hydraulic limit valve 23.
Under the condition that the proportional electromagnet 221 fails or the current input device of the host system fails, the thrust F of the proportional electromagnet 221 is 0, and the plunger variable displacement pump 1 can be controlled to keep the minimum set displacement Y through the hydraulic limit valve 23. Since the minimum set displacement is set by adjusting the hydraulic limit valve 23, it can be set according to the minimum displacement required for the operation of the main machine. When the proportional electromagnet 221 suddenly fails, the displacement of the plunger variable displacement pump 1 is not reduced to 0, but is maintained at the minimum set displacement Y, and the main machine can still work, so that the safety is effectively improved.
To achieve electric proportional positive displacement control of the plunger variable displacement pump 1, a control current X1 is set, X1 being greater than X. When the control current is X1, the thrust Fx1 of the proportional electromagnet 221 is greater than the resultant force of Fs and Ft, the proportional electromagnet 221 pushes the electric proportional control valve 22 to be in the left position, and oil in the lower variable cylinder 11 flows back to realize unloading; under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, the displacement of the plunger variable displacement pump 1 is increased, and the small connecting rod 112 drives the feedback rod 21 to perform the electric proportional controlThe valve 22 moves in the direction to compress the feedback spring 222, causing Fs to increase gradually until the combined force of Fs and Ft is greater than Fx1Pushing the electric proportional control valve 22 to switch to the right position; oil liquid flows into the lower variable cylinder 11, the displacement of the plunger variable pump 1 is reduced under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, the small connecting rod 112 drives the feedback rod 21 to move towards the direction far away from the electric proportional control valve 22, the compression of the feedback spring 222 is released, and Fs is gradually reduced until the resultant force of Fs and Ft is less than Fx1The proportional electromagnet 221 pushes the electric proportional control valve 22 to return to the left position. The above processes are carried out repeatedly, and the displacement dynamic balance control of the plunger variable displacement pump 1 under the control current X1 is realized, namely the electric proportion positive displacement control is realized.
In order to realize the pressure cut-off control of the plunger variable displacement pump 1, the opening pressure of the pressure cut-off control valve 24 is set by adjusting the adjusting spring of the pressure cut-off control valve 24, when the pressure at the plunger pump oil outlet 102 reaches the opening pressure, the hydraulic pressure received by the pressure cut-off control valve 24 is greater than the adjusting spring force, the pressure cut-off control valve 24 is switched from the left position to the right position, the high-pressure oil at the plunger pump oil outlet 102 directly enters the lower variable cylinder 11 through the pressure cut-off control valve 24 and the control oil path 30, and the plunger variable displacement pump 1 is variable to the zero displacement under the differential action of the lower variable cylinder 11 and the upper variable cylinder 12, so that the pressure cut-off control is realized.
In summary, the hydraulic limit valve 23 only controls the electric proportional control valve 22 in the minimum displacement Y and the displacement range below the minimum displacement Y set by the hydraulic limit valve 23, and there is no limitation on the pressure cut-off control valve 24, other control methods carried by the plunger variable displacement pump 1 itself, and the output flow rate control of the plunger variable displacement pump 1 by the host system, so that when the proportional solenoid 221 suddenly fails, the plunger variable displacement pump 1 can still provide the output flow rate in the minimum displacement Y state, and the pressure cut-off control can still be realized by the pressure cut-off control valve 24.
As shown in fig. 3, the hydraulic limit valve adjusting mechanism 231 includes a valve housing 2311 and a locking nut 2312, the valve housing 2311 penetrates into the valve body 20 to be connected with the valve body 20, and the locking nut 2312 surrounds the valve housing 2311 to be connected with the valve housing 2311. The valve housing 2311 is coaxially disposed with the hydraulic limit valve 23, and contacts the hydraulic limit valve 23. Specifically, the valve sleeve 2311 is provided with external threads, the joint of the valve body 20 and the valve sleeve 2311 is provided with internal threads, and the valve sleeve 2311 is in threaded connection with the valve body 20. The valve housing 2311 has an external hexagonal configuration. When the hydraulic limiting valve adjusting mechanism 231 is installed, firstly, the locking nut 2312 is screwed out to separate the locking nut 2312 from the valve body 20, then the depth of the valve sleeve 2311 penetrating into the valve body 20 is adjusted through the external hexagonal structure of the valve sleeve 2311, the depth is directly related to the minimum displacement Y, after the setting is completed, the locking nut 2312 is screwed down to generate an interaction force with the valve body 29, the interaction force enables the thread tooth surfaces of the valve sleeve 2311 and the valve body 20, which are meshed with each other, to generate extrusion stress, and due to the self-locking of the spiral angle, the valve sleeve 2311 is locked, so that the setting of the minimum displacement of the plunger variable displacement pump 1 is completed.
With reference to fig. 4 and 5, fig. 4 is a pressure-displacement graph of the integrated control system of the plunger variable displacement pump in the case of the failure of the proportional solenoid, and fig. 5 is a pressure-displacement graph of the integrated control system of the plunger variable displacement pump in the case of the failure of the proportional solenoid in the prior art. Therefore, by using the scheme of the invention, when the proportional electromagnet fails, the variable displacement pump of the plunger can be changed to the set minimum displacement of the hydraulic limiting valve, the work of the host is maintained, the safety is improved, and meanwhile, the pressure cut-off control valve can still work normally without influencing the pressure cut-off control.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A plunger variable pump integrated control system is installed in combination with a plunger variable pump, the plunger variable pump comprises a swash plate, the swash plate is installed inside the plunger variable pump, the inclination angle of the swash plate determines the displacement of the plunger variable pump, the plunger variable pump is provided with a plunger pump oil inlet and a plunger pump oil outlet, and the plunger variable pump integrated control system is characterized by comprising a large connecting rod, a small connecting rod, a lower variable cylinder, an upper variable cylinder, an integrated control assembly and a control oil way; the large connecting rod and the small connecting rod are respectively connected with two ends of the swash plate, the large connecting rod is used as a piston of the lower variable cylinder and is connected with the lower variable cylinder, and the small connecting rod is used as a piston of the upper variable cylinder and is connected with the upper variable cylinder; the upper variable cylinder is normally communicated with high-pressure oil of an oil outlet of the plunger pump or control oil of an external control port; the integrated control assembly is connected with an oil outlet of the plunger pump through an oil way, the integrated control assembly is connected with an oil return oil way, and the integrated control assembly is connected with the small connecting rod; the lower variable cylinder is connected with the integrated control assembly through the control oil way; the integrated control assembly comprises a valve body, a feedback rod, an electric proportional control valve, a hydraulic control valve and a pressure cut-off control valve, wherein the electric proportional control valve, the hydraulic control valve and the pressure cut-off control valve are installed in the valve body; one end of the feedback rod is connected with the small connecting rod, and the other end of the feedback rod is inserted into the valve body and is connected with the electric proportional control valve through a feedback spring; one end of the electric proportional control valve, which is far away from the feedback rod, is provided with a proportional electromagnet, and the electric proportional control valve is provided with an electric proportional control adjusting spring; the oil return oil way is connected with the electric proportional control valve, and the feedback rod is positioned between the electric proportional control valve and the hydraulic control valve; the pressure cut-off control valve is provided with a regulating spring, and the opening pressure of the pressure cut-off control valve is set by regulating the regulating spring of the pressure cut-off control valve; the upper end of the pressure cut-off control valve is connected with an oil outlet of the plunger pump through an oil path, and the upper end of the pressure cut-off control valve is connected with the lower variable cylinder through the control oil path; the lower end of the pressure cut-off control valve is connected with the lower end of the electric proportional control valve through an oil way; the upper end of the electric proportional control valve is connected with the lower end of the hydraulic limiting valve through an oil way; the upper end of the hydraulic limiting valve is connected with the lower end of the pressure cut-off control valve through an oil way; the electric proportional control valve, the hydraulic limiting valve and the pressure cut-off control valve are all provided with a left position and a right position, and the electric proportional control valve, the hydraulic limiting valve and the pressure cut-off control valve change the communication state of oil passages at the upper end and the lower end of the electric proportional control valve through the switching of the left position and the right position.
2. The integrated control system of a plunger variable pump according to claim 1, wherein the hydraulic limit valve is arranged in parallel with the electro-proportional control valve.
3. The integrated control system for a plunger variable displacement pump according to claim 2, wherein a hydraulic limit adjusting mechanism is installed at one end of the hydraulic control valve away from the feedback rod, and the set minimum displacement of the plunger variable displacement pump is adjusted by adjusting the hydraulic limit adjusting mechanism.
4. The integrated control system for a plunger variable pump according to claim 3, wherein the hydraulic limit valve adjusting mechanism comprises a valve sleeve and a lock nut, the valve sleeve penetrates into the valve body to be connected with the valve body, the lock nut surrounds the valve sleeve to be connected with the valve sleeve, and the valve sleeve and the hydraulic limit valve are coaxially arranged and contact with the hydraulic limit valve.
5. The integrated control system for a plunger variable displacement pump as recited in claim 4, wherein said valve housing has external threads, said valve body has internal threads at a junction with said valve housing, said valve housing is threadedly coupled with said valve body, and said valve housing has an external hexagonal configuration.
6. The integrated control system of the plunger variable displacement pump according to claim 1, wherein when the electric proportional control valve is in a right position, the hydraulic limit valve is in a right position, and the pressure cut-off control valve is in a left position, high-pressure oil at an oil outlet of the plunger pump or control oil at an external control port flows into the lower variable displacement cylinder through the integrated control assembly and the control oil path.
7. The integrated control system of a plunger variable displacement pump according to claim 1, wherein when the electro-proportional control valve is in a right position, the hydraulic limit valve is in a left position, and the pressure cut-off control valve is in a left position, the hydraulic limit valve blocks oil flow to the lower variable cylinder.
8. The integrated control system of a plunger variable displacement pump according to claim 1, wherein when the electro-proportional control valve is in a left position and the pressure cutoff control valve is in a left position, the oil in the lower variable cylinder flows back.
9. The integrated control system of the plunger variable displacement pump according to claim 1, wherein when the pressure cut-off control valve is in a right position, high-pressure oil at the oil outlet of the plunger pump enters the lower variable displacement cylinder through the pressure cut-off control valve and the control oil path.
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| CN201911184508.0A CN110848111B (en) | 2019-11-27 | 2019-11-27 | Plunger variable pump integrated control system |
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| CN201911184508.0A CN110848111B (en) | 2019-11-27 | 2019-11-27 | Plunger variable pump integrated control system |
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| CN110848111B true CN110848111B (en) | 2021-09-10 |
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| CN112302895A (en) * | 2020-11-25 | 2021-02-02 | 力源液压（苏州）有限公司 | Axial plunger pump |
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| CN107630847A (en) * | 2017-09-15 | 2018-01-26 | 太原理工大学 | Electric ratio pressure continuously regulates and controls hydraulic motor/pump |
| CN109469594A (en) * | 2018-09-29 | 2019-03-15 | 北京航空航天大学 | Continuous voltage regulating electric-hydraulic proportion shaft orientation plunger variable pump for plane hydraulic system |
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| CN200978783Y (en) * | 2006-11-02 | 2007-11-21 | 陕西航天动力高科技股份有限公司 | Electrohydraulic ratio variable piston pump |
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| CN110848111A (en) | 2020-02-28 |
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Address after: No. 29 Caohu Avenue, Caohu Street, Suzhou City, Jiangsu Province, 215000 Patentee after: Suzhou Liyuan Hydraulic Co.,Ltd. Address before: No.29 Caohu Avenue, Xiangcheng District, Suzhou City, Jiangsu Province Patentee before: LIYUAN HYDRAULIC (SUZHOU) Co.,Ltd. |
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