CN119900740A - A closed hydraulic system, a vehicle and a control method of the closed hydraulic system - Google Patents
A closed hydraulic system, a vehicle and a control method of the closed hydraulic system Download PDFInfo
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- CN119900740A CN119900740A CN202510397816.0A CN202510397816A CN119900740A CN 119900740 A CN119900740 A CN 119900740A CN 202510397816 A CN202510397816 A CN 202510397816A CN 119900740 A CN119900740 A CN 119900740A
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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
- F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
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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
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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
- F15B13/024—Pressure relief valves
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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
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/14—Energy-recuperation means
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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
- F15B2211/30—Directional control
- F15B2211/305—Directional control characterised by the type of valves
- F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
本发明涉及车辆技术领域，具体公开了一种闭式液压系统、车辆及闭式液压系统的控制方法，闭式液压系统包括补油泵、液压油缸、第一闭式泵和平衡阀，补油泵的输入端连接油箱，补油泵的输出端连接补油油路，液压油缸具有有杆腔和无杆腔，第一闭式泵的一端通过第一油路连接无杆腔，另一端通过第二油路连接有杆腔，使得第一闭式泵和液压油缸之间形成液压回路，第一闭式泵能正转且能反转；平衡阀能使第一油路和第二油路两者中油压较小的一者与补油油路连通，能够弥补有杆腔和无杆腔两者流量上的差异，并且使补油油路中温度较低的油液能够和第一油路或第二油路中温度较高的油液进行置换，优化系统的热平衡，无需设置温度监控，保证液压油缸正常运行。
, The hydraulic cylinder has a plurality of independently controlled cams, and a plurality of independently controlled cams are connected to each other via a plurality of independently controlled cams. The plurality of independently controlled cams have independently controlled cams, and a plurality of independently controlled cams are connected to each other via a plurality of independently controlled cams.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to a closed hydraulic system, a vehicle and a control method of the closed hydraulic system.
Background
Various mechanical devices widely use single-rod double-acting piston hydraulic cylinders, and the mechanism is driven to move by controlling the expansion and contraction direction and speed of a piston rod of the hydraulic cylinder.
In the prior art, as disclosed in the earlier patent with the application number CN202110530288.3, a closed hydraulic system, specifically, a mechanical arm closed electrohydraulic control system of an asymmetric cylinder, is connected with a rod cavity and a rodless cavity of the hydraulic cylinder through an oil pump, so as to realize the flow of oil in the two cavities, and meanwhile, an accumulator is also configured to compensate the flow difference between the rod cavity and the rodless cavity and recover part of energy, so that the decoupling of the oil cylinder can be realized, but in the system, the accumulator can overflow at high pressure when reaching the maximum pressure, and also overflow at high pressure when reaching the maximum pressure, the pipeline connected with the rod cavity and the rodless cavity can cause power loss, and meanwhile, larger heat can be generated to affect the heat balance of the system.
Disclosure of Invention
The invention aims to provide a closed hydraulic system, a vehicle and a control method of the closed hydraulic system, so as to optimize heat balance of the existing closed hydraulic system.
In one aspect, the invention provides a closed hydraulic system comprising an oil supplementing pump, a hydraulic cylinder and a first closed pump, wherein the input end of the oil supplementing pump is connected with an oil tank, the output end of the oil supplementing pump is connected with an oil supplementing oil path, the hydraulic cylinder is provided with a rod cavity and a rodless cavity, one end of the first closed pump is connected with a first oil path, the first oil path is connected with the rodless cavity, the other end of the first closed pump is connected with a second oil path, the second oil path is connected with the rod cavity, the first closed pump can positively rotate and can reversely rotate, and the closed hydraulic system further comprises a balance valve which is configured to enable one with smaller oil pressure in the first oil path and the second oil path to be communicated with the oil supplementing oil path.
As a preferred technical solution of the closed hydraulic system, the closed hydraulic system further includes:
the second closed pump can rotate positively and reversely, one end of the second closed pump is connected with an oil supplementing oil way, the other end of the second closed pump is connected with a third oil way, and the third oil way is communicated with the first oil way;
The first reversing valve is arranged in the third oil way and is used for controlling the connection and disconnection of the third oil way.
As the preferable technical scheme of closed hydraulic system, closed hydraulic system still includes the motor, and with the battery that the motor electricity is connected, the motor simultaneously with first closed pump with second closed pump transmission is connected, just the motor can drive simultaneously first closed pump with the second closed pump rotates, and works as first closed pump to first oil circuit pump oil, the second closed pump to third oil circuit pump oil.
As a preferred technical solution of the closed hydraulic system, the closed hydraulic system further includes:
The two ends of the first bypass oil way are respectively connected with the oil supplementing oil way and the third oil way, and the joint of the first bypass oil way and the third oil way is positioned between the second closed pump and the first reversing valve;
The second reversing valve is arranged on the first bypass oil way and is used for controlling the connection and disconnection of the first bypass oil way.
As a preferred technical solution of the closed hydraulic system, the closed hydraulic system further includes:
The two ends of the second bypass oil circuit are respectively connected with the oil supplementing oil circuit and the third oil circuit, and the joint of the second bypass oil circuit and the third oil circuit is positioned between the second closed pump and the first reversing valve;
And a check valve provided to the second bypass oil passage and configured to allow only the oil to flow from the oil supplementing oil passage to the third oil passage through the second bypass oil passage.
As a preferable technical scheme of the closed hydraulic system, the closed hydraulic system further comprises a regeneration oil path connected between the first oil path and the second oil path, and a regeneration valve arranged on the regeneration oil path, wherein the regeneration valve is used for controlling the communication and disconnection of the regeneration oil path.
As a preferable technical solution of the closed hydraulic system, the closed hydraulic system further includes a first relief valve connected between the oil-compensating oil passage and the first oil passage, the first relief valve being configured to enable oil in the first oil passage to be relieved to the oil-compensating oil passage when exceeding a first set pressure;
The closed hydraulic system further includes a second relief valve connected between the oil make-up passage and the second oil passage, the second relief valve being configured to enable oil in the second oil passage to be relieved to the oil make-up passage when the second set pressure is exceeded.
As a preferable technical solution of the closed hydraulic system, the closed hydraulic system further includes an oil replenishment overflow valve connected between the oil replenishment oil path and the oil tank, the oil replenishment overflow valve being configured to enable oil in the oil replenishment oil path to overflow to the oil tank when exceeding a third set pressure.
As a preferable technical scheme of the closed hydraulic system, the balance valve comprises a first interface, a second interface and a third interface, wherein the first interface is communicated with the first oil way, the second interface is communicated with the second oil way, the third interface is communicated with the oil supplementing oil way, when the oil pressure of the first oil way is larger than that of the second oil way, the balance valve enables the second interface to be communicated with the third interface, and the first interface is disconnected, and when the oil pressure of the first oil way is smaller than that of the second oil way, the balance valve enables the first interface to be communicated with the third interface, and the second interface is disconnected.
On the other hand, the invention also provides a vehicle, which comprises the closed hydraulic system in any scheme, wherein the hydraulic cylinder is a movable arm cylinder, a bucket rod cylinder or a bucket cylinder.
In still another aspect, the present invention provides a control method of a closed hydraulic system, implemented by the closed hydraulic system in any one of the above aspects, the closed hydraulic system further includes a second closed pump and a motor, the second closed pump is capable of rotating forward and backward, one end of the second closed pump is connected to an oil supplementing oil path, the other end is connected to a third oil path, the third oil path is communicated with the first oil path, the motor is in transmission connection with the first closed pump and the second closed pump at the same time, and the motor is capable of driving the first closed pump and the second closed pump to rotate at the same time, the control method of the closed hydraulic system includes:
Acquiring the position of a control handle;
Determining the expansion and contraction requirement of a piston rod of the hydraulic oil cylinder based on the position of the control handle;
Acquiring a high-pressure oil cavity of a hydraulic oil cylinder, wherein the high-pressure oil cavity of the hydraulic oil cylinder is one with larger oil pressure in a rod cavity and a rodless cavity of the hydraulic oil cylinder;
Acquiring the expansion and contraction requirements of a piston rod and the corresponding relation between a high-pressure oil cavity of a hydraulic oil cylinder and a working quadrant of a closed hydraulic system, wherein the working quadrant of the closed hydraulic system comprises a first quadrant, a second quadrant, a third quadrant and a fourth quadrant;
determining a working quadrant of a closed hydraulic system based on the expansion and contraction requirements of the piston rod, a high-pressure oil cavity of the hydraulic oil cylinder and the corresponding relation;
Judging whether the working quadrant of the closed hydraulic system is a third quadrant or a fourth quadrant;
If yes, determining the rotating speed of the motor based on the working quadrant.
When judging whether the working quadrant of the closed hydraulic system is the third quadrant or the fourth quadrant, if not, the control method of the closed hydraulic system further comprises the following steps:
Determining a required rotational speed of the motor based on the position of the steering handle;
determining a required flow rate of the oil pump based on the required rotation speed;
acquiring the maximum oil pressure in the rod cavity and the oil pressure in the rodless cavity;
determining a required power of an oil pump based on the required flow rate and the maximum oil pressure;
Obtaining rated power of a motor;
Judging the size of a half of the required power of the oil pump and the rated power of the motor;
If the required power of the oil pump is more than or equal to half of the rated power of the motor, only the first closed pump is started, and if the required power of the oil pump is less than half of the rated power of the motor, the first closed pump and the second closed pump are simultaneously started.
As a preferred technical scheme of the control method of the closed hydraulic system, when only the first closed pump is started, and when the first closed pump and the second closed pump are simultaneously started, the control method of the closed hydraulic system further comprises the following steps of;
Judging whether the working quadrant of the closed hydraulic system is a second quadrant or not;
if not, determining the rotating speed of the motor based on the working quadrant.
As a preferable technical scheme of the control method of the closed hydraulic system, the closed hydraulic system further comprises a battery electrically connected with the motor;
When judging whether the working quadrant of the closed hydraulic system is the second quadrant, if so, the control method of the closed hydraulic system further comprises the following steps:
Judging whether the opening degree of the control handle exceeds a set opening degree based on the position of the control handle;
If yes, the motor generates electricity and stores the electricity in a battery, and if not, the rotating speed of the motor is determined based on the working quadrant.
The beneficial effects of the invention are as follows:
The invention provides a closed hydraulic system, a vehicle and a control method of the closed hydraulic system, wherein the closed hydraulic system comprises an oil supplementing pump, a hydraulic cylinder, a first closed pump and a balance valve, the input end of the oil supplementing pump is connected with an oil tank, the output end of the oil supplementing pump is connected with an oil supplementing oil path, the hydraulic cylinder is provided with a rod cavity and a rodless cavity, one end of the first closed pump is connected with a first oil path, the first oil path is connected with the rodless cavity, the other end of the first closed pump is connected with a second oil path, the second oil path is connected with the rod cavity, the first closed pump can positively rotate and can reversely rotate, one of the first oil path and the second oil path, which is smaller in oil pressure, is communicated with the oil supplementing oil path through the first oil path and the second oil path, one of the first oil path and the second oil path, which is smaller in oil pressure, is communicated with the oil supplementing oil path through the balance valve, the difference in flow between the rod cavity and the rodless cavity can be made up, the lower temperature oil in the oil supplementing oil path can be replaced with the higher temperature in the oil supplementing oil path, the oil cylinder can normally run, the temperature of the hydraulic system can be guaranteed, and the normal running of the hydraulic system can be ensured, and the temperature of the balance system can be monitored.
Drawings
FIG. 1 is a schematic view of a closed hydraulic system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the working quadrants of a closed hydraulic system according to an embodiment of the present invention;
FIG. 3 is a first flow chart of a method of controlling a closed hydraulic system according to an embodiment of the present invention;
fig. 4 is a second flowchart of a control method of a closed hydraulic system according to an embodiment of the present invention.
In the figure:
1. the hydraulic cylinder is provided with a rod cavity, a rod cavity and a rodless cavity;
2. A make-up pump; 3, a first closed pump, 4, a balance valve, 5, an oil tank, 6, an oil supplementing oil way, 7, a first oil way, 8, a second oil way, 9, a second closed pump, 10, a third oil way, 11, a first reversing valve, 12, a first bypass oil way, 13, a second reversing valve, 14, a second bypass oil way, 15, a one-way valve, 16, a motor, 17, a regeneration oil way, 18, a regeneration valve, 19, a first overflow valve, 20, a second overflow valve, 21, an oil supplementing overflow valve, 22 and an oil supplementing motor.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first location" and "second location" are two distinct locations and wherein the first feature is "above," "over" and "over" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is level above the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.
In the description of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
The existing mechanical arm closed electrohydraulic control system of the asymmetric cylinder is connected with a rod cavity and a rodless cavity of the hydraulic cylinder through an oil pump so as to realize the flow of oil in the two cavities, and meanwhile, an energy accumulator is also arranged to compensate the flow difference between the rod cavity and the rodless cavity and recover part of energy, so that decoupling of the oil cylinder can be realized, but in the system, the energy accumulator overflows at high pressure when reaching the maximum pressure, and the pipeline connected with the rod cavity and the rodless cavity overflows at high pressure, so that power loss is caused, larger heat is generated to influence the heat balance of the system, and in order to avoid the excessive high temperature of the oil in the system, additional temperature monitoring is needed, hot oil in the system is required to overflow to an oil tank through a low-pressure overflow valve when the temperature is abnormal, and the oil in the oil tank is replenished into the system, so that the normal work of the oil cylinder is influenced.
In this regard, the present embodiment provides a closed hydraulic system to solve the above-mentioned problems.
As shown in fig. 1, the closed hydraulic system includes a makeup pump 2, a hydraulic cylinder 1, a first closed pump 3, and a balance valve 4. The hydraulic cylinder 1 is provided with a rod cavity 101 and a rodless cavity 102, one end of a first closed pump 3 is connected with a first oil circuit 7, the first oil circuit 7 is connected with the rodless cavity 102, the other end of the first closed pump 3 is connected with a second oil circuit 8, the second oil circuit 8 is connected with the rod cavity 101, the first closed pump 3 can rotate forwards and reversely, and a balance valve 4 is configured to enable one of the first oil circuit 7 and the second oil circuit 8 with smaller oil pressure to be communicated with the oil supplementing oil circuit 6.
In the closed hydraulic system provided in this embodiment, the first closed pump 3 is connected with the two cavity hydraulic circuits of the hydraulic cylinder 1 through the first oil circuit 7 and the second oil circuit 8, when the first closed pump 3 rotates forward, the oil with the rod cavity 101 can be conveyed to the rodless cavity 102 so that the piston rod of the hydraulic cylinder 1 extends out, and when the first closed pump 3 rotates backward, the oil in the rodless cavity 102 is conveyed to the rod cavity 101 so that the piston rod of the hydraulic cylinder 1 retracts. Because there is the difference in the sectional area of the rod-shaped cavity 101 and the rodless cavity 102, therefore, there is the flow difference in the rod-shaped cavity 101 and the rodless cavity 102, and the balance valve 4 is used for communicating the oil compensating oil path 6 with the smaller oil pressure of the first oil path 7 and the second oil path 8, so that the flow difference can be made up, the oil in the oil compensating oil path 6 can be replaced with the oil in the hydraulic circuit, the oil temperature in the oil compensating oil path 6 is relatively low, when the oil temperature in the hydraulic circuit is too high, the oil temperature in the hydraulic circuit can be effectively reduced, the normal oil temperature in the hydraulic circuit is further ensured, the thermal balance of the system is optimized, temperature monitoring is not required, and the normal operation of the hydraulic cylinder 1 can be ensured.
Note that the oil replenishment pump 2 may be driven by the oil replenishment motor 22. The number of the hydraulic cylinders 1 may be one or a plurality, and when the number of the hydraulic cylinders 1 is a plurality, the rodless cavities 102 of the hydraulic cylinders 1 are all communicated with the first oil path 7, and the rod cavities 101 of the hydraulic cylinders 1 are all communicated with the second oil path 8. Specifically, the present embodiment exemplarily gives a scheme in which the number of hydraulic cylinders 1 is two.
Optionally, the closed hydraulic system further comprises a first relief valve 19 connected between the oil charging oil passage 6 and the first oil passage 7, the first relief valve 19 being configured to enable oil in the first oil passage 7 to be relieved to the oil charging oil passage 6 when the first set pressure is exceeded. By providing the first relief valve 19, the pressure of the oil in the first oil passage 7 and the rodless chamber 102 can be prevented from exceeding the first set pressure. The first set pressure can be set according to actual needs.
Optionally, the closed hydraulic system further includes a second relief valve 20 connected between the oil compensating oil passage 6 and the second oil passage 8, the second relief valve 20 being configured to enable oil in the second oil passage 8 to be relieved to the oil compensating oil passage 6 when the second set pressure is exceeded. By providing the second relief valve 20, the pressure of the oil in the second oil passage 8 and the rod chamber 101 can be prevented from exceeding the second set pressure. The second set pressure can be set according to actual needs.
Optionally, the closed hydraulic system further comprises a makeup relief valve 21 connected between the makeup oil path 6 and the tank 5, the makeup relief valve 21 being configured to enable oil in the makeup oil path 6 to overflow to the tank 5 when the third set pressure is exceeded. The oil supply pressure of the oil supply passage 6 can be limited by providing the oil supply relief valve 21. The third set pressure can be set according to actual needs.
Optionally, the closed hydraulic system further comprises a second closed pump 9 and a first reversing valve 11. The second closed pump 9 can rotate forward and reversely, one end of the second closed pump 9 is connected with the oil supplementing oil circuit 6, the other end of the second closed pump 9 is connected with the third oil circuit 10, the third oil circuit 10 is communicated with the first oil circuit 7, the first reversing valve 11 is arranged on the third oil circuit 10, and the first reversing valve 11 is used for controlling the communication and disconnection of the third oil circuit 10. Specifically, when the first reversing valve 11 is communicated with the third oil passage 10, part of oil in the rodless cavity 102 can be pumped to the rod cavity 101 through the first closed pump 3 and the other part of oil in the rodless cavity 102 can be pumped to the oil supplementing oil passage 6 through the second closed pump 9, or oil in the rod cavity 101 can be pumped to the rodless cavity 102 through the first closed pump 3 and the oil in the oil supplementing oil passage 6 can be pumped to the rodless cavity 102 through the second closed pump 9, so that the expansion and contraction efficiency of a piston rod of the hydraulic oil cylinder 1 can be improved, and the flow difference between the rod cavity 101 and the rodless cavity 102 can be further compensated.
Note that, when the first switching valve 11 opens the third oil passage 10, the oil is driven to flow between the rod-shaped chamber 101 and the rodless chamber 102 only by the first closed pump 3. In this embodiment, the first reversing valve 11 is specifically a two-position two-way valve. The first closed pump 3 and the second closed pump 9 are both constant displacement pumps.
Optionally, the closed hydraulic system further includes a motor 16, and a battery (not shown in the drawing) electrically connected to the motor 16, where the motor 16 is in driving connection with the first closed pump 3 and the second closed pump 9 at the same time, and the motor 16 can drive the first closed pump 3 and the second closed pump 9 to rotate at the same time, and when the first closed pump 3 pumps oil to the first oil path 7, the second closed pump 9 pumps oil to the third oil path 10. Specifically, the battery supplies electric power to the motor 16, and the first and second closed pumps 3 and 9 can be actively driven by the motor 16 to simultaneously rotate in the forward direction or simultaneously rotate in the reverse direction. It should be noted that, when the first closed pump 3 and the second closed pump 9 are simultaneously reversed, they may be driven by not only the motor 16 but also the oil. Specifically, if the piston rod of the hydraulic cylinder 1 is retracted rapidly by means of the dead weight of the outer part, the oil can drive the first closed pump 3 and the second closed pump 9 to rotate reversely and drive the motor 16 to rotate reversely, so that the motor 16 is driven to generate electricity and store in a battery, the recycling of system energy is realized, the heating power of the system is reduced, and the system efficiency is improved.
In other embodiments, the first closed pump 3 and the second closed pump 9 can also be driven by an internal combustion engine.
Optionally, the closed hydraulic system further comprises a first bypass oil path 12 and a second reversing valve 13, two ends of the first bypass oil path 12 are respectively connected with the oil supplementing oil path 6 and the third oil path 10, a joint of the first bypass oil path 12 and the third oil path 10 is located between the second closed pump 9 and the first reversing valve 11, the second reversing valve 13 is arranged on the first bypass oil path 12, and the second reversing valve 13 is used for controlling the connection and disconnection of the first bypass oil path 12. When the second reversing valve 13 is communicated with the first bypass oil way 12, the oil inlet and outlet pressures of the second closed pump 9 are the same, the second closed pump 9 performs self circulation through the first bypass oil way 12, does not do work externally, only the first closed pump 3 does work outwards, and can reduce energy loss, and when the second reversing valve 13 is disconnected from the first bypass oil way 12 and the first reversing valve 11 is communicated with the third oil way 10, the second closed pump 9 and the first closed pump 3 do work together. Specifically, the second reversing valve 13 in this embodiment is a two-position two-way valve.
Optionally, the closed hydraulic system further comprises a second bypass oil circuit 14 and a check valve 15. The two ends of the second bypass oil path 14 are respectively connected with the oil supplementing oil path 6 and the third oil path 10, the connection part of the second bypass oil path 14 and the third oil path 10 is positioned between the second closed pump 9 and the first reversing valve 11, the one-way valve 15 is arranged on the second bypass oil path 14, and the one-way valve 15 is configured to only allow oil to flow from the oil supplementing oil path 6 to the third oil path 10 through the second bypass oil path 14. When the first bypass oil way 12 is disconnected by the second reversing valve 13, the third oil way 10 is disconnected by the first reversing valve 11, and the first closed pump 3 and the second closed pump 9 are reversed, the oil inlet and outlet pressures of the second closed pump 9 are the same, the second closed pump 9 can perform self circulation through the second bypass oil way 14, and no work is done to the outside, so that energy loss is reduced.
Optionally, the closed hydraulic system further includes a regeneration oil path 17 connected between the first oil path 7 and the second oil path 8, and a regeneration valve 18 disposed on the regeneration oil path 17, where the regeneration valve 18 is used to control the connection and disconnection of the regeneration oil path 17. When the regeneration valve 18 communicates the regeneration oil path 17, the regeneration oil path 17 communicates the first oil path 7 and the second oil path 8, and at this time, the oil in the rodless cavity 102 may directly flow into the rod cavity 101 through the regeneration valve 18 without passing through the first closed pump 3 and the second closed pump 9, so that the piston rod of the hydraulic cylinder 1 can have the fastest movement speed.
Optionally, the balance valve 4 comprises a first interface, a second interface and a third interface, wherein the first interface is communicated with the first oil way 7, the second interface is communicated with the second oil way 8, the third interface is communicated with the oil supplementing oil way 6, when the oil pressure of the first oil way 7 is larger than that of the second oil way 8, the balance valve 4 enables the second interface to be communicated with the third interface, and the first interface is disconnected, and when the oil pressure of the first oil way 7 is smaller than that of the second oil way 8, the balance valve 4 enables the first interface to be communicated with the third interface, and the second interface is disconnected. Preferably, when the oil pressure of the first oil path 7 is equal to the oil pressure of the second oil path 8, the first interface, the second interface and the third interface are all disconnected, so that the pressure stability of the oil in the rod cavity 101 and the rodless cavity 102 of the hydraulic oil cylinder 1 can be ensured, and the position stability of the piston rod can be further ensured.
Specifically, in the present embodiment, the balance valve 4 is a three-position three-way valve. The balance valve 4 has a left position, a right position, and a neutral position, and when the balance valve 4 is in the left position, the first port and the third port are connected, and the second port is disconnected, and when the balance valve 4 is in the right position, the second port and the third port are connected, and the first port is disconnected. When the balance valve 4 is in the neutral position, the first port, the second port and the third port are all disconnected.
It should be noted that the direction of movement of the piston rod of the hydraulic cylinder 1 and the direction of the load force received by the piston rod of the hydraulic cylinder 1 together determine the oil pressure in the rodless chamber 102 and the rod-like chamber 101, and when the direction of the load force is defined to be the same as the direction of movement of the piston rod of the hydraulic cylinder 1, the load force is a negative load, and when the direction of the load force is opposite to the direction of movement of the piston rod of the hydraulic cylinder 1, the load force is a positive load. Specifically, (1) when the piston rod of the hydraulic cylinder 1 is retracted inwards, the oil pressure in the rodless cavity 102 is larger than the oil pressure in the rod cavity 101 when the piston rod of the hydraulic cylinder 1 is subjected to a negative load, the balance valve 4 is communicated with the oil compensating oil passage 6 and the second oil passage 8, when the piston rod of the hydraulic cylinder 1 is subjected to a positive load, the oil pressure in the rod cavity 101 is larger than the oil pressure in the rodless cavity 102, the balance valve 4 is communicated with the oil compensating oil passage 6 and the first oil passage 7, when the piston rod of the hydraulic cylinder 1 is extended outwards, the oil pressure in the rodless cavity 102 is smaller than the oil pressure in the rod cavity 101, the balance valve 4 is communicated with the oil compensating oil passage 6 and the first oil passage 7, and when the piston rod of the hydraulic cylinder 1 is subjected to a positive load, the oil pressure in the rod cavity 101 is smaller than the oil pressure in the rodless cavity 102, and the balance valve 4 is communicated with the oil compensating oil passage 6 and the second oil passage 8.
In this embodiment, the balance valve 4 is specifically a hydraulic control valve, the balance valve 4 has a first hydraulic control end and a second hydraulic control end, the first hydraulic control end is connected to the first oil path 7, the second hydraulic control end is connected to the second oil path 8, the first hydraulic control end and the second hydraulic control end are respectively located at two sides of the spool of the balance valve 4, and the oil of the first hydraulic control end and the oil of the second hydraulic control end directly acts on the spool of the balance valve 4, and the force of the oil of the first hydraulic control end acting on the spool of the balance valve 4 and the force of the oil of the second hydraulic control end acting on the spool of the balance valve 4 are compared to determine the stop position of the spool of the balance valve 4. Specifically, the balance valve 4 is positioned at the left position when the oil pressure of the first hydraulic control end is smaller than the oil pressure of the second hydraulic control end, the balance valve 4 is positioned at the right position when the oil pressure of the first hydraulic control end is larger than the oil pressure of the second hydraulic control end, and the balance valve 4 is positioned at the middle position when the oil pressure of the first hydraulic control end is equal to the oil pressure of the second hydraulic control end. In other embodiments, the balancing valve 4 may also be an electrically controlled valve.
Alternatively, the valves and the oil pump can be integrated on the motor 16, so that the complexity of the system and the complexity of control can be reduced, and the occupied space of the structure can be reduced.
The embodiment also provides a vehicle comprising the closed hydraulic system. The vehicle may be a digger, loader, or the like. Taking the excavator as an example, the hydraulic cylinder 1 can be a movable arm cylinder, a bucket cylinder or a bucket rod cylinder of the excavator.
The embodiment also provides a control method of the closed hydraulic system. The control method of the closed hydraulic system is implemented through the closed hydraulic system. Specifically, referring to fig. 2 and 3, the control method of the closed hydraulic system includes the following steps:
S100, acquiring the position of the control handle.
The position of the operating handle can be detected by a position sensor provided on the operating handle. The control handle is used for controlling the rotating speed and the rotating direction of the motor 16, so as to further control the extending and retracting direction and the moving speed of the piston rod of the hydraulic oil cylinder 1.
And S200, determining the telescopic requirement of the piston rod of the hydraulic oil cylinder 1 based on the position of the control handle.
The controller may store a first mapping relation between the position of the control handle and the expansion demand of the piston rod of the hydraulic cylinder 1 in advance, and the expansion demand of the piston rod may be determined according to the position of the control handle and the first mapping relation. Wherein the retraction demand of the piston rod comprises a piston rod extension demand and a piston rod retraction demand. The first mapping relationship can be obtained through a plurality of experiments in the early stage.
S300, acquiring a high-pressure oil cavity of the hydraulic oil cylinder 1.
The high-pressure oil chamber of the hydraulic cylinder 1 is one in which the oil pressure is larger in both the rod chamber 101 and the rodless chamber 102 of the hydraulic cylinder 1. Specifically, the oil pressure sensor can detect the oil pressure in the rod cavity 101 and the rodless cavity 102 respectively, and the cavity corresponding to the larger oil pressure is the high-pressure oil cavity of the hydraulic oil cylinder 1.
S400, acquiring the expansion and contraction requirements of a piston rod and the corresponding relation between a high-pressure oil cavity of the hydraulic oil cylinder 1 and a working quadrant of a closed hydraulic system.
The expansion and contraction requirements of the piston rod and the corresponding relation between the high-pressure oil cavity of the hydraulic oil cylinder 1 and the working quadrant of the closed hydraulic system can be obtained through a large number of experiments in the earlier stage and stored in the controller in advance.
The working quadrant is a constant power curve distribution diagram of the closed hydraulic system, the abscissa is flow, the ordinate is pressure, the working quadrant of the closed hydraulic system comprises a first quadrant, a second quadrant, a third quadrant and a fourth quadrant, and each quadrant corresponds to the expansion and contraction requirements of different piston rods and the high-pressure oil cavity of the hydraulic oil cylinder 1. Therefore, the working quadrant of the closed hydraulic system can be determined from the above correspondence by the expansion and contraction requirements of the piston rod and the high-pressure oil chamber of the hydraulic cylinder 1.
It will be appreciated that the load to which the piston rod is subjected may be a negative load or a positive load, which may result in a greater oil pressure in the rodless chamber 102, a greater oil pressure in the rod chamber 101, and a greater oil pressure in the rodless chamber 102, or a greater oil pressure in the rod chamber 101, when the piston rod is retracted. Based on this, as shown in fig. 2, when the piston rod is extended, if the oil pressure in the rodless chamber 102 is large, the closed hydraulic system is in the first quadrant, if the oil pressure in the rod chamber 101 is large, the closed hydraulic system is in the fourth quadrant, when the piston rod is retracted, if the oil pressure in the rodless chamber 102 is large, the closed hydraulic system is in the second quadrant, and if the oil pressure in the rod chamber 101 is large, the closed hydraulic system is in the third quadrant.
And S500, determining a working quadrant of the closed hydraulic system based on the expansion and contraction requirements of the piston rod, the high-pressure oil cavity of the hydraulic oil cylinder 1 and the corresponding relation.
And S600, judging whether the working quadrant of the closed hydraulic system is a third quadrant or a fourth quadrant.
If yes, then S700 is performed.
And S700, determining the rotating speed of the motor 16 based on the working quadrant.
In this embodiment, when the working quadrant of the closed hydraulic system is in the third quadrant or the fourth quadrant, only one working state of the closed hydraulic system is corresponding. Specifically, when the working quadrant of the closed hydraulic system is in the third quadrant or the fourth quadrant, only the first closed pump 3 is turned on, the second closed pump 9 is turned off, and specifically, the third oil path 10 can be closed through the first reversing valve 11 to realize that the second closed pump 9 does not participate in the output.
Therefore, when the working quadrant of the closed hydraulic system is in the third quadrant or the fourth quadrant, the first closed pump 3 can directly participate in output, and the second closed pump 9 does not participate in output, and at this time, the quick adjustment of the closed hydraulic system can be realized only by determining the rotation speed of the motor 16 according to the working quadrant.
Specifically, the second mapping relation between the working quadrant and the rotation speed of the motor 16 is pre-stored in the controller, the rotation speed of the motor 16 can be determined through the second mapping relation between the working quadrant of the hydraulic system and the rotation speed, and the motor 16 can output the rotation speed, so that the rapid adjustment of the closed hydraulic system is realized. The second mapping relationship can be obtained through a plurality of experiments in the early stage.
Alternatively, when S600 is performed, if not, S800 is performed.
S800, determining the required rotation speed of the motor 16 based on the position of the steering handle.
The controller has stored therein a third map of the position of the joystick and the required rotational speed of the motor 16. The required rotational speed of the motor 16 may be determined based on the position of the steering handle and a third map, which may be obtained through a number of experiments in the early stage.
And S900, determining the required flow of the oil pump based on the required rotation speed.
The controller is pre-stored with a fourth mapping relation between the required rotation speed and the required flow of the oil pump, and the required flow of the oil pump can be determined according to the required rotation speed and the fourth mapping relation. The fourth mapping relationship can be obtained through a plurality of experiments in the earlier stage.
It should be noted that the required flow rate of the oil pump corresponds to the total required flow rates of the first and second closed pumps 3 and 9. In this embodiment, the first closed pump 3 and the second closed pump 9 are fixed displacement pumps, and the fourth mapping relationship is specifically that the required flow rate of the oil pump is equal to the product of the sum of the displacements of the first closed pump 3 and the second closed pump 9 and the required rotation speed.
S1000, obtaining the maximum oil pressure in both the oil pressure in the rod chamber 101 and the oil pressure in the rodless chamber 102.
And S1100, determining the required power of the oil pump based on the required flow and the maximum oil pressure.
The fifth mapping relation of the required flow, the maximum oil pressure and the required power of the oil pump is prestored in the controller. The required power of the oil pump can be determined according to the required flow, the maximum oil pressure and a fifth mapping relation, and the fifth mapping relation can be obtained through a large number of experiments in the earlier stage.
And S1200, acquiring rated power of the motor 16.
The rated power of the motor 16 is related to the model of the motor 16 and is pre-stored in the controller.
And S1300, judging whether the required power of the oil pump is not less than half of the rated power of the motor 16.
If yes, execute S1400, if not, execute S1500.
S1400, only the first closed pump 3 is turned on, and S700 is returned.
S1500, the first closed pump 3 and the second closed pump 9 are started at the same time.
Specifically, when the working quadrant of the closed hydraulic system is in the first quadrant or the second quadrant, two working states of the closed hydraulic system are respectively corresponding, wherein one working state is that only the first closed pump 3 participates in output, the second closed pump 9 does not participate in output, and the other working state is that both the first closed pump 3 and the second closed pump 9 participate in output. Thus, when the determination determines that the operating quadrant of the closed hydraulic system is in the first quadrant or the second quadrant, it is further determined whether the motor 16 is capable of operating both closed pumps simultaneously.
Specifically, if the required power of the oil pump is greater than or equal to half of the rated power of the motor 16, it is indicated that the motor 16 can only drive one closed pump to work at the same time, if the motor 16 drives two closed pumps to work at the same time, the actual power of the motor 16 will exceed the rated power, and when the required power of the oil pump is less than half of the rated power of the motor 16, the motor 16 can drive two closed pumps to work at the same time and cannot exceed the rated power.
Through steps S1200 to S1500, the piston rod of the hydraulic cylinder 1 can be made to have the maximum expansion and contraction speed without exceeding the rated power of the motor 16.
Optionally, referring to fig. 4, the control method of the closed hydraulic system further includes the following steps after step S1500;
and S1600, judging whether the working quadrant of the closed hydraulic system is a second quadrant or not.
If not, S700 is executed, and if so, S1700 is executed.
S1700, judging whether the opening degree of the control handle exceeds the set opening degree based on the position of the control handle.
The opening of the control handle is in direct proportion to the range of the control handle deviated from the initial position, so that the range of the control handle deviated from the initial position can be determined according to the position of the control handle, and the opening of the control handle can be further determined. The set opening degree may be set according to actual needs, and a scheme of setting the opening degree to 50% is exemplarily given in the present embodiment.
If yes, execution is S1800, otherwise execution is S700.
S1800 the motor 16 generates electricity and stores it in the battery.
In S1400, after the first closed pump 3 is turned on, the motor 16 executes the rotation speed of the corresponding working quadrant regardless of whether the working quadrant of the closed hydraulic system is the first quadrant or the second quadrant. However, in S1500, when the first closed pump 3 and the second closed pump 9 are simultaneously turned on to perform control according to the situation, the motor 16 may be caused to perform the rotation speed corresponding to the working quadrant when the working quadrant of the closed hydraulic system is the first quadrant, but when the working quadrant of the hydraulic system is the second quadrant, the piston rod of the hydraulic cylinder 1 is subjected to a negative load, and when the piston rod needs to be quickly retracted, the first closed pump 3 and the second closed pump 9 may be driven by oil liquid to reverse rotation so as to generate electricity by the motor 16 to recover energy, and when the piston rod needs not to be quickly retracted, the rotation speed of the motor 16 may be controlled according to the actual needs.
Therefore, when the working quadrant of the hydraulic system is the second quadrant, it is also necessary to measure, according to the opening of the operating handle, whether the driver desires a quick retraction of the piston rod, if so, power generation can be performed, and if not, the motor 16 is caused to perform the rotation speed of the corresponding working quadrant.
It is to be understood that the above examples of the present invention are provided for clarity of illustration only and are not limiting of the embodiments of the present invention. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are desired to be protected by the following claims.
Claims (14)
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| CN202510397816.0A CN119900740A (en) | 2025-04-01 | 2025-04-01 | A closed hydraulic system, a vehicle and a control method of the closed hydraulic system |
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| CN202510397816.0A CN119900740A (en) | 2025-04-01 | 2025-04-01 | A closed hydraulic system, a vehicle and a control method of the closed hydraulic system |
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| CN116989023A (en) * | 2023-09-28 | 2023-11-03 | 潍柴动力股份有限公司 | An EHA system |
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| US20130276441A1 (en) * | 2010-12-27 | 2013-10-24 | Volvo Construction Equipment Ab | Hydraulic pump for construction machinery |
| CN112648244A (en) * | 2021-02-19 | 2021-04-13 | 太原理工大学 | Pump-valve-cooperated multi-actuator electro-hydraulic system and control method thereof |
| CN113431812A (en) * | 2021-07-16 | 2021-09-24 | 龙岩畅丰专用汽车有限公司 | Intelligent control system for emergency vehicle |
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