CN113212093A - Hydraulic system capable of realizing constant pressure control and load sensitive control and control method - Google Patents
Hydraulic system capable of realizing constant pressure control and load sensitive control and control method Download PDFInfo
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- CN113212093A CN113212093A CN202110565070.1A CN202110565070A CN113212093A CN 113212093 A CN113212093 A CN 113212093A CN 202110565070 A CN202110565070 A CN 202110565070A CN 113212093 A CN113212093 A CN 113212093A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
- B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
- B60G17/0408—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics details, e.g. antifreeze for suspension fluid, pumps, retarding means per se
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
- B60G17/0195—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the regulation being combined with other vehicle control systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
- B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
- B60G17/0416—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics regulated by varying the resiliency of hydropneumatic suspensions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
- B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
- B60G17/056—Regulating distributors or valves for hydropneumatic systems
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- Mechanical Engineering (AREA)
- Automation & Control Theory (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
A hydraulic system and a control method capable of realizing constant pressure control and load sensitive control. The problem of current suspension control system need additionally increase auxiliary pump and hydraulic control oil circuit is solved. The multi-way valve comprises a control module, a second feedback oil way, a shuttle valve and at least one working module, the load sensitive variable pump comprises a variable pump, a control valve, a cut-off valve and a control oil cylinder, the control oil cylinder comprises a piston rod, a rod cavity and a rodless cavity, the shuttle valve selects pressure oil of the first feedback oil way or the second feedback oil way and inputs the pressure oil to a spring cavity of the control valve, and the pressure oil of the first oil way enters the rodless cavity by overcoming the pressure of the spring cavity of the cut-off valve and interacts with the pressure oil in the rod cavity to enable the piston rod to move. The invention also has the advantages of simple structure, convenient assembly, reliable action, long service life and the like.
Description
Technical Field
The invention relates to a hydraulic system, in particular to a hydraulic system capable of realizing constant pressure control and load sensitive control and a control method.
Background
The engineering vehicle active suspension system generally adopts an electro-hydraulic control hydraulic suspension, the hydraulic suspension system can automatically adjust the expansion amount of a suspension hydraulic cylinder according to the condition of a road surface, the expansion or contraction of the suspension hydraulic cylinder needs to be quickly responded in the driving process due to uncertainty of the height and unevenness change of the road surface, a power source of a hydraulic oil cylinder is from a pump, and the response of the pump needs to be quick when the oil cylinder quickly executes actions. The suspension control of the existing engineering vehicle is mainly controlled by adding an independent auxiliary gear pump, the auxiliary gear pump of the independent control suspension is always in a working state to ensure that a pump can quickly respond when a suspension oil cylinder needs to be driven, the suspension basically does not need to be regulated and controlled when the suspension runs on a flat road surface, at the moment, the auxiliary gear pump still needs to be operated all the time, the loss of energy consumption is caused, the auxiliary gear pump is independently added to control, the cost of the whole control system is also increased, and the existing control scheme is not only high in cost but also not energy-saving.
Disclosure of Invention
In order to solve the problem that an auxiliary pump and a hydraulic control oil way are additionally added to the existing suspension control system in the background art, the invention provides a hydraulic system and a control method capable of realizing constant pressure control and load sensitive control.
The technical scheme of the invention is as follows: a hydraulic system capable of realizing constant pressure control and load sensitive control comprises a load sensitive variable pump, a multi-way valve, a reversing valve, a first feedback oil path and a suspension module, wherein the multi-way valve comprises a control module, a second feedback oil path, a shuttle valve and at least one working module, the load sensitive variable pump comprises a variable pump, a control valve, a cut-off valve and a control oil cylinder, the control oil cylinder comprises a piston rod, a rod cavity and a rodless cavity, the variable pump is respectively connected with the first oil path and the second oil path, the first oil path is respectively connected with a control cavity of the control valve, a control cavity of the cut-off valve and the rod cavity, the second oil path is respectively connected with the suspension module, the reversing valve and the multi-way valve, the reversing valve is provided with a disconnected first position and a second position enabling the second oil path and the first feedback oil to be communicated, the shuttle valve selects pressure oil of the first feedback oil path or the second feedback oil path and inputs the pressure oil to a spring cavity of the control valve, the pressure oil of the first oil way enters the rodless cavity by overcoming the pressure of the spring cavity of the cut-off valve and interacts with the pressure oil in the rod cavity to enable the piston rod to move to adjust the output flow of the variable displacement pump.
As a further development of the invention, the control valve is driven to close by the pressure of the control valve spring chamber when the directional control valve is in the second position.
As a further improvement of the invention, the reversing valve is a two-position three-way reversing valve.
As a further improvement of the invention, the reversing valve is an electromagnetic reversing valve.
As a further improvement of the invention, the control module is provided with a main overflow valve and a three-way flow valve, and the second oil way is respectively connected with the oil return port through the main overflow valve and the three-way flow valve.
As a further improvement of the invention, the control module is provided with an electromagnetic directional valve and a feedback overflow valve, and the second feedback oil path is connected with the oil return port through the electromagnetic directional valve and the feedback overflow valve respectively.
As a further improvement of the invention, the electromagnetic directional valve is a normally open type electromagnetic directional valve.
As a further improvement of the invention, a pressure compensation valve is arranged on the control module, and the second oil path is communicated with the working module through the pressure compensation valve.
As a further improvement of the invention, the multiway valve comprises a constant flow valve and a pressure reducing valve.
A control method comprises the hydraulic system capable of realizing constant pressure control and load sensitive control,
when the reversing valve is in the first position, the reversing valve is cut off, and the output pressure of the load-sensitive variable pump is determined by the load to play a role in load-sensitive control;
when the reversing valve is in a second position, the variable pump outputs pressure oil, the pressure oil simultaneously acts on different positions in the system through the first oil path and the second oil path, the pressure oil output of the second oil path reaches the multi-way valve, meanwhile, part of the pressure oil acts on a spring cavity of the control valve through the reversing valve and the shuttle valve, and part of the pressure oil acts on a control cavity of the control valve and a rod cavity of the control oil cylinder through the first oil path; the control valve spring cavity and the control valve control cavity are simultaneously subjected to the same hydraulic acting force output by the variable pump, and the control valve spring cavity is also subjected to the action of the spring force, so that the control valve is always kept in a stop working state, and at the moment, the rod cavity of the control oil cylinder is subjected to the action of pressure oil in the first oil way to push the piston rod to move leftwards to increase the displacement of the variable pump;
if the working module of the multi-way valve is not reversed at this time, when the system is in an idle running state, pressure oil acts on the control end of the cut-off valve through the first oil way, because the variable pump continuously discharges the pressure oil, the system pressure can be quickly increased to the spring set pressure of the spring cavity of the cut-off valve at this time, and the cut-off valve is pushed to reverse, so that the high-pressure oil acts on the rodless cavity of the control oil cylinder through the right position of the cut-off valve, at this time, the rodless cavity and the rod cavity of the control oil cylinder simultaneously input hydraulic oil with the same pressure, because the action area of the rodless cavity is larger, the pressure oil can push the piston rod of the control oil cylinder to move rightwards, so that the displacement of the pump is reduced to the minimum displacement, and at this time, the variable pump is maintained in the working state of the minimum displacement and the maximum pressure;
if the working module rod of the multi-way valve 2 is reversed, when the system executes corresponding control action, pressure oil output by the variable pump is supplied to the corresponding working module through the second oil way and the multi-way valve, and at the moment, if the maximum output flow of the variable pump is larger than the flow required by the working module; one part of flow is supplied to the working module to act, redundant flow can enable the system pressure to continuously rise to the spring set pressure of the shut-off valve, the shut-off valve is reversed to the right position to work, pressure oil enters a rodless cavity of the control oil cylinder through the right position of the shut-off valve and pushes a piston rod of the control oil cylinder to move rightwards to reduce the output flow of the variable pump, when the output flow of the variable pump is reduced to the flow which does not meet the requirement of the working module, the system pressure can be reduced to be smaller than the set pressure of the spring cavity of the shut-off valve, the shut-off valve is reversed to the left position working state at the moment, the variable pump can enter the previous circulation working state with increased displacement, under the working condition that the maximum output flow of the variable pump is larger than the flow required by the working module, the working state of the pump is in a real-time dynamic adjustment working state at the moment, and the output pressure of the variable pump can be maintained at the set pressure of the shut-off valve, namely in a constant pressure state, and the flow required by the working module is constantly output; if the maximum output flow of the variable pump is smaller than the flow required by the working module; the variable pump is in the working state of the maximum displacement, all the output pressure oil is supplied to the working module, and at the moment, no redundant pressure oil is left in the first oil way to establish higher pressure, so the output pressure of the variable pump is determined by the load carried by the working module, and at the moment, the variable pump can avoid the saturation state from occurring in the design of a hydraulic system and the working state of the hydraulic system with the working state of the load pressure and the maximum displacement.
The invention has the advantages that the suspension system is combined with the vehicle system, the arrangement of an additional auxiliary pump and an oil way is avoided, the auxiliary pump is prevented from working all the time, the energy consumption is reduced, and meanwhile, the suspension system can act under a constant pressure, so that the action of a product is stable and reliable. The invention also has the advantages of simple structure, convenient assembly, reliable action, long service life and the like.
Drawings
FIG. 1 is a hydraulic schematic of an embodiment of the present invention.
Fig. 2 is a hydraulic schematic diagram of the load sensitive variable displacement pump of fig. 1.
FIG. 3 is a hydraulic schematic of the multiplex valve of FIG. 1.
In the figure, 1, a load-sensitive variable pump; 11. a variable displacement pump; 12. a control valve; 13. a shut-off valve; 14. controlling the oil cylinder; 141. a piston rod; 142. a rod cavity; 143. a rodless cavity; 2. a multi-way valve; 21. a control module; 22. a shuttle valve; 23. a main overflow valve; 24. a three-way flow valve; 25. an electromagnetic directional valve; 26. a feedback overflow valve; 27. a pressure compensating valve; 28. a constant flow valve; 29. a pressure reducing valve; 3. a diverter valve; 41. a first feedback oil path; 42. a second feedback oil path; 5. a suspension module; 61. A first oil passage; 62. a second oil passage; 7. a working module; t, an oil return port.
Detailed Description
The embodiments of the invention will be further described with reference to the accompanying drawings in which:
referring to fig. 1 and 2-3, a hydraulic system capable of realizing constant pressure control and load sensitive control includes a load sensitive variable pump 1, a multi-way valve 2, a reversing valve 3, a first feedback oil path 41 and a suspension module 5, wherein the multi-way valve includes a control module 21, a second feedback oil path 42, a shuttle valve 22 and at least one working module 7, the load sensitive variable pump includes a variable pump 11, a control valve 12, a cut-off valve 13 and a control cylinder 14, the control cylinder includes a piston rod 141, a rod chamber 142 and a rodless chamber 143, the variable pump is respectively connected with a first oil path 61 and a second oil path 62, the first oil path is respectively connected with the control valve chamber, the cut-off valve chamber and the rod chamber, the second oil path is respectively connected with the suspension module, the reversing valve and the multi-way valve, and the reversing valve has a first position for cutting off and a second oil path, And the shuttle valve selects pressure oil of the first feedback oil path or the second feedback oil path and inputs the pressure oil to the spring cavity of the control valve, and the pressure oil of the first oil path enters the rodless cavity by overcoming the pressure of the spring cavity of the stop valve and interacts with the pressure oil in the rod cavity to enable the piston rod to move to adjust the output flow of the variable displacement pump. The invention has the advantages that the suspension system is combined with the vehicle system, the arrangement of an additional auxiliary pump and an oil way is avoided, the auxiliary pump is prevented from working all the time, the energy consumption is reduced, and meanwhile, the suspension system can act under a constant pressure, so that the action of a product is stable and reliable. The invention also has the advantages of simple structure, convenient assembly, reliable action, long service life and the like.
The control valve is driven to close by the pressure of the control valve spring chamber when the reversing valve is in the second position. Specifically, when the reversing valve is in the second position, the pressure of the control valve can be maintained, so that the control valve is in the closed position, and the system pressure is determined by the elastic force of the spring cavity of the cutoff valve, so that the system is in a constant pressure state when the reversing valve is opened.
The reversing valve is a two-position three-way reversing valve. Specifically, the reversing valve is an electromagnetic reversing valve. The structure ensures that the reversing valve is convenient and reliable to control.
And the control module is provided with a main overflow valve 23 and a three-way flow valve 24, and the second oil way is connected with the oil return port T through the main overflow valve and the three-way flow valve respectively. The main overflow valve plays a role in limiting the highest pressure protection pump and other elements of the system; the three-way flow valve plays a role in a load sensitive system: the unloading system has the advantages of total flow, pressure required by system establishment, flow control of each valve and certain buffering and damping functions. Aiming at the variable pump load sensitive system, the flow output by the pump can be self-regulated through the control valve according to the system requirements, so that the function of the three-way flow valve in the system is almost replaced by the control valve, and the mechanical variable mechanism of the variable pump needs a certain time to complete the regulation of the flow when the variable pump self-regulates the output displacement, so that when the pump is regulated from large displacement to small displacement, the three-way flow valve can play a certain unloading role, and the system impact is reduced.
And the control module is provided with an electromagnetic directional valve 25 and a feedback overflow valve 26, and the second feedback oil path is connected with the oil return port through the electromagnetic directional valve and the feedback overflow valve respectively. Specifically, the electromagnetic directional valve is a normally open type electromagnetic directional valve. Two oil ports of the two normally open type electromagnetic directional valves are respectively connected to a second feedback oil path and an oil return port, and the second feedback oil path and the oil return port are always in a connected state in the non-working state of the electromagnetic directional valve, so that the system is unloaded; if the system needs to work normally, the electromagnetic directional valve needs to be electrified and switched to a normally closed state, and the connection between the second feedback oil path and the oil return port is disconnected, so that the second feedback oil path can establish pressure to ensure that the system can work normally; and the feedback overflow valve limits the highest pressure of the second feedback oil path, and protects the system and the actuating element.
The control module is provided with a pressure compensation valve 27, and the second oil path is communicated with the working module through the pressure compensation valve. The pressure compensation valve is used for keeping the pressure difference between the second oil path and the second feedback oil path at a constant value, namely ensuring that the pressure difference between the front part and the rear part of the load sensitive valve is kept constant, and the pressure compensation valve is actually equivalent to a constant-difference pressure reducing valve; when the system works in a constant pressure state, the pressure output by the pump is a set value of the shut-off valve, the output pressure of the pump is usually far larger than the pressure required by the driving actuating mechanism, if the high-pressure oil of the pump does not pass through the pressure compensation valve but directly acts on the load sensitive multi-way valve, the pressure difference between the front part and the rear part of the load sensitive multi-way valve is very large, the flow is determined by the flow area and the pressure difference, and at the moment, the pressure difference between the front part and the rear part of the load sensitive multi-way valve is very large, so that the load sensitive multi-way valve cannot control the flow basically. A pressure compensation valve is added between a pump and a load sensitive multi-way valve, so that high-pressure oil output by the pump passes through the pressure compensation valve and then acts on the load sensitive multi-way valve in a constant low pressure mode, the constant low pressure at the moment is the pressure in a second oil path which is the pressure added by the spring force of the pressure compensation valve, a spring cavity of the pressure compensation valve is subjected to the spring force of the pressure compensation valve and the pressure in the second feedback oil path, the pressure in the second feedback oil path is determined by the load, a non-spring cavity of the pressure compensation valve is subjected to the pressure in the second oil path, a spring cavity and a non-spring cavity of the pressure compensation valve are respectively subjected to the pressure at two sides and are always maintained in a balanced state, and if the pressure at the second oil path side is changed (increased or reduced), the force at the two sides of a valve core of the pressure compensation valve is unbalanced, the valve core can perform corresponding displacement to adjust the opening amount, and adjusting the corresponding excess flow to enable the two sides of the pressure compensation valve to tend to be balanced. The pressure in the second oil path is always higher than the pressure in the second feedback oil path, the higher pressure is the spring setting force of the pressure compensation valve, and the spring setting force is a fixed value, so that a fixed pressure difference is always kept between the front part and the rear part of the load-sensitive multi-way valve, and the output flow of the corresponding working oil port of the load-sensitive multi-way valve can be adjusted by only adjusting the opening of the throttling groove of the valve rod of the load-sensitive multi-way valve.
The multi-way valve comprises a constant flow valve 28 and a pressure reducing valve 29. The constant flow valve has the advantages that the oil liquid generates tiny flow, the pressure conduction effect is achieved, and the situation that the pressure of the closed oil duct cannot be built and conducted is avoided. The pressure reducing valve is used for reducing the pressure of high-pressure oil output by the pump to a lower pressure and supplying the low-pressure oil to the pilot oil way, and the pilot oil way is used for pushing the working valve rod of the load-sensitive multi-way valve working module to change direction. The pressure oil passing through the pressure reducing valve is normally controlled by an electric proportional pressure reducing valve to change the working valve rod of the working module. The electric proportional pressure reducing valve is used for reducing pressure of pressure oil in a pilot oil path for the second time, the pressure of the second pressure reduction is proportional to input current, and the reversing displacement of the valve rod can be accurately controlled.
A control method comprises the hydraulic system capable of realizing constant pressure control and load sensitive control,
when the reversing valve is in the first position, the reversing valve is cut off, and the output pressure of the load-sensitive variable pump is determined by the load to play a role in load-sensitive control;
when the reversing valve is in a second position, the variable pump outputs pressure oil, the pressure oil simultaneously acts on different positions in the system through the first oil path and the second oil path, the pressure oil output of the second oil path reaches the multi-way valve, meanwhile, part of the pressure oil acts on a spring cavity of the control valve through the reversing valve and the shuttle valve, and part of the pressure oil acts on a control cavity of the control valve and a rod cavity of the control oil cylinder through the first oil path; the control valve spring cavity and the control valve control cavity are simultaneously subjected to the same hydraulic acting force output by the variable pump, and the control valve spring cavity is also subjected to the action of the spring force, so that the control valve is always kept in a stop working state, and at the moment, the rod cavity of the control oil cylinder is subjected to the action of pressure oil in the first oil way to push the piston rod to move leftwards to increase the displacement of the variable pump;
if the working module of the multi-way valve is not reversed at this time, when the system is in an idle running state, pressure oil acts on the control end of the cut-off valve through the first oil way, because the variable pump continuously discharges the pressure oil, the system pressure can be quickly increased to the spring set pressure of the spring cavity of the cut-off valve at this time, and the cut-off valve is pushed to reverse, so that the high-pressure oil acts on the rodless cavity of the control oil cylinder through the right position of the cut-off valve, at this time, the rodless cavity and the rod cavity of the control oil cylinder simultaneously input hydraulic oil with the same pressure, because the action area of the rodless cavity is larger, the pressure oil can push the piston rod of the control oil cylinder to move rightwards, so that the displacement of the pump is reduced to the minimum displacement, and at this time, the variable pump is maintained in the working state of the minimum displacement and the maximum pressure;
if the working module rod of the multi-way valve 2 is reversed, when the system executes corresponding control action, pressure oil output by the variable pump is supplied to the corresponding working module through the second oil way and the multi-way valve, and at the moment, if the maximum output flow of the variable pump is larger than the flow required by the working module; one part of flow is supplied to the working module to act, redundant flow can enable the system pressure to continuously rise to the spring set pressure of the shut-off valve, the shut-off valve is reversed to the right position to work, pressure oil enters a rodless cavity of the control oil cylinder through the right position of the shut-off valve and pushes a piston rod of the control oil cylinder to move rightwards to reduce the output flow of the variable pump, when the output flow of the variable pump is reduced to the flow which does not meet the requirement of the working module, the system pressure can be reduced to be smaller than the set pressure of the spring cavity of the shut-off valve, the shut-off valve is reversed to the left position working state at the moment, the variable pump can enter the previous circulation working state with increased displacement, under the working condition that the maximum output flow of the variable pump is larger than the flow required by the working module, the working state of the pump is in a real-time dynamic adjustment working state at the moment, and the output pressure of the variable pump can be maintained at the set pressure of the shut-off valve, namely in a constant pressure state, and the flow required by the working module is constantly output; if the maximum output flow of the variable pump is smaller than the flow required by the working module; the variable pump is in the working state of the maximum displacement, all the output pressure oil is supplied to the working module, and at the moment, no redundant pressure oil is left in the first oil way to establish higher pressure, so the output pressure of the variable pump is determined by the load carried by the working module, and at the moment, the variable pump can avoid the saturation state from occurring in the design of a hydraulic system and the working state of the hydraulic system with the working state of the load pressure and the maximum displacement.
In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.
The skilled person should understand that: although the invention has been described in terms of the above specific embodiments, the inventive concept is not limited thereto and any modification applying the inventive concept is intended to be included within the scope of the patent claims.
Claims (10)
1. The hydraulic system capable of realizing constant pressure control and load sensitive control is characterized by comprising a load sensitive variable pump (1), a multi-way valve (2), a reversing valve (3), a first feedback oil way (41) and a suspension module (5), wherein the multi-way valve comprises a control module (21), a second feedback oil way (42), a shuttle valve (22) and at least one working module (7), the load sensitive variable pump comprises a variable pump (11), a control valve (12), a cut-off valve (13) and a control oil cylinder (14), the control oil cylinder comprises a piston rod (141), a rod cavity (142) and a rodless cavity (143), the variable pump is respectively connected with a first oil way (61) and a second oil way (62), the first oil way is respectively connected with a control cavity of the control valve, a control cavity of the cut-off valve and the rod cavity, and the second oil way is respectively connected with the suspension module, The shuttle valve selects pressure oil of the first feedback oil path or the second feedback oil path and inputs the pressure oil to a spring cavity of the control valve, and the pressure oil of the first oil path enters the rodless cavity by overcoming the pressure of the spring cavity of the cut-off valve and interacts with the pressure oil in the rod cavity to enable the piston rod to move to adjust the output flow of the variable displacement pump.
2. The hydraulic system of claim 1, wherein the control valve is closed by pressure in a spring chamber of the control valve when the directional control valve is in the second position.
3. The hydraulic system for constant pressure control and load sensitive control of claim 1, wherein said directional control valve is a two-position, three-way directional control valve.
4. The hydraulic system for constant pressure control and load sensitive control as claimed in claim 1, wherein said directional control valve is a solenoid directional control valve.
5. The hydraulic system capable of realizing constant pressure control and load sensitive control according to claim 1, wherein the control module is provided with a main overflow valve (23) and a three-way flow valve (24), and the second oil path is connected with the oil return port (T) through the main overflow valve and the three-way flow valve respectively.
6. The hydraulic system capable of realizing constant pressure control and load sensitive control according to claim 1, wherein the control module is provided with an electromagnetic directional valve (25) and a feedback overflow valve (26), and the second feedback oil path is connected with the oil return port through the electromagnetic directional valve and the feedback overflow valve respectively.
7. The hydraulic system capable of realizing constant pressure control and load sensitive control according to claim 6, wherein the electromagnetic directional valve is a normally open type electromagnetic directional valve.
8. The hydraulic system capable of realizing constant pressure control and load sensitive control according to claim 1, wherein the control module is provided with a pressure compensation valve (27), and the second oil path is communicated with the working module through the pressure compensation valve.
9. A hydraulic system with constant pressure and load sensitive control as claimed in claim 1, characterized in that the multiplex valve comprises a constant flow valve (28) and a pressure reducing valve (29).
10. A control method characterized by: comprising a hydraulic system capable of constant pressure control and load-sensitive control according to any one of claims 1 to 9,
when the reversing valve is in the first position, the reversing valve is cut off, and the output pressure of the load-sensitive variable pump is determined by the load to play a role in load-sensitive control;
when the reversing valve is in a second position, the variable pump outputs pressure oil, the pressure oil simultaneously acts on different positions in the system through the first oil path and the second oil path, the pressure oil output of the second oil path reaches the multi-way valve, meanwhile, part of the pressure oil acts on a spring cavity of the control valve through the reversing valve and the shuttle valve, and part of the pressure oil acts on a control cavity of the control valve and a rod cavity of the control oil cylinder through the first oil path; the control valve spring cavity and the control valve control cavity are simultaneously subjected to the same hydraulic acting force output by the variable pump, and the control valve spring cavity is also subjected to the action of the spring force, so that the control valve is always kept in a stop working state, and at the moment, the rod cavity of the control oil cylinder is subjected to the action of pressure oil in the first oil way to push the piston rod to move leftwards to increase the displacement of the variable pump;
if the working module of the multi-way valve is not reversed at this time, when the system is in an idle running state, pressure oil acts on the control end of the cut-off valve through the first oil way, because the variable pump continuously discharges the pressure oil, the system pressure can be quickly increased to the spring set pressure of the spring cavity of the cut-off valve at this time, and the cut-off valve is pushed to reverse, so that the high-pressure oil acts on the rodless cavity of the control oil cylinder through the right position of the cut-off valve, at this time, the rodless cavity and the rod cavity of the control oil cylinder simultaneously input hydraulic oil with the same pressure, because the action area of the rodless cavity is larger, the pressure oil can push the piston rod of the control oil cylinder to move rightwards, so that the displacement of the pump is reduced to the minimum displacement, and;
if the working module rod of the multi-way valve 2 is reversed, when the system executes corresponding control action, pressure oil output by the variable pump is supplied to the corresponding working module through the second oil way and the multi-way valve, and at the moment, if the maximum output flow of the variable pump is larger than the flow required by the working module; one part of flow is supplied to the working module to act, redundant flow can enable the system pressure to continuously rise to the spring set pressure of the shut-off valve, the shut-off valve is reversed to the right position to work, pressure oil enters a rodless cavity of the control oil cylinder through the right position of the shut-off valve and pushes a piston rod of the control oil cylinder to move rightwards to reduce the output flow of the variable pump, when the output flow of the variable pump is reduced to the flow which does not meet the requirement of the working module, the system pressure can be reduced to be smaller than the set pressure of the spring cavity of the shut-off valve, the shut-off valve is reversed to the left position working state at the moment, the variable pump can enter the previous circulation working state with increased displacement, under the working condition that the maximum output flow of the variable pump is larger than the flow required by the working module, the working state of the pump is in a real-time dynamic adjustment working state at the, and the flow required by the working module is constantly output; if the maximum output flow of the variable pump is smaller than the flow required by the working module; the variable pump is in the working state of the maximum displacement, all the output pressure oil is supplied to the working module, and at the moment, no redundant pressure oil is left in the first oil way to establish higher pressure, so the output pressure of the variable pump is determined by the load carried by the working module, and at the moment, the variable pump can avoid the saturation state from occurring in the design of a hydraulic system and the working state of the hydraulic system with the working state of the load pressure and the maximum displacement.
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| WO2023070929A1 (en) * | 2021-10-29 | 2023-05-04 | 上海三一重机股份有限公司 | Quantitative and constant-variable switchable hydraulic system, and control method therefor and operation machine |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2023070929A1 (en) * | 2021-10-29 | 2023-05-04 | 上海三一重机股份有限公司 | Quantitative and constant-variable switchable hydraulic system, and control method therefor and operation machine |
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