Energy-saving hydraulic control system of lifting mechanism
By adopting the connection between rodless cavity and rod-cavity in the lifting mechanism hydraulic cylinder system and the combination of proportional throttle valve and energy accumulator group, the problem of heavy object potential energy recovery is solved, and an efficient and reliable potential energy recovery effect is achieved.
Patent Information
- Application Number
- CN202421534238.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-01
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-07-01
AI Technical Summary
When the hydraulic cylinder of the lifting mechanism controls the lifting and lowering of heavy objects, it is urgent to use simple and reliable technology to recover the potential energy of heavy objects.
A system including a lifting hydraulic cylinder, a rod-cavity oil circuit, a rod-cavity oil circuit, a connecting oil circuit, a system oil source, an energy storage unit, a first control structure, a second control structure and a proportional throttle valve are adopted. Through the communication between the rodless cavity and the rod-well cavity, the recovery of the potential energy of the heavy object is achieved by using a proportional throttle valve and the accumulator group.
It realizes effective recycling of heavy objects potential energy, simplifies equipment configuration, reduces system complexity and cost, and improves system reliability and efficiency.
Smart Images
Figure CN222650243U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydraulic control, in particular to an energy-saving hydraulic control system for a lifting mechanism. Background Art
[0002] Hydraulic control systems are used to drive the lifting of heavy objects on many heavy industrial equipment. In many working conditions, the gravitational potential energy of the lifted objects and the lifting equipment itself can be recycled and reused to achieve energy-saving effects. For example, walking-beam heating furnaces, walking-beam transport chains, coil transport trolleys and other equipment in the steel and metallurgical fields, the weight of the equipment themselves and the lifted objects often ranges from tens of tons to thousands of tons. The potential energy recovery of heavy objects is crucial to the energy saving of the entire hydraulic system. Therefore, when using hydraulic cylinders to lift heavy objects, it is urgent to recover the potential energy of the heavy objects.
[0003] The common potential energy recovery hydraulic control method requires the addition of more equipment. For example, there is the use of a special three-chamber hydraulic cylinder technology. This technology requires the hydraulic cylinder to be converted into a special hydraulic cylinder, and also involves modifications to the civil engineering foundation, etc.; there is also a pump-controlled recovery technology, which requires the addition of a dedicated pump and motor control system, increasing the installed power and floor space; there is also the use of a rod-chamber valve control technology, which also requires the addition of an additional proportional valve for control, making the control more complicated and increasing the cost. Utility Model Content
[0004] In view of the above problems existing in the prior art, the technical problem to be solved by the utility model is: when the hydraulic cylinder of the lifting mechanism controls the lifting of a heavy object, it is urgent to adopt a simple and reliable technology to recover the potential energy of the heavy object.
[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions: including: a lifting hydraulic cylinder, a rod chamber oil circuit, a rodless chamber oil circuit, a connecting oil circuit, a system oil source, an accumulator group, a first control structure, a second control structure and a proportional throttle valve; the rodless chamber of the lifting hydraulic cylinder is connected to the system oil source through the rodless chamber oil circuit; the rod chamber of the lifting hydraulic cylinder is connected to the oil tank through the rod chamber oil circuit; the two ends of the connecting oil circuit are respectively connected to the rod chamber oil circuit and the rodless chamber oil circuit to directly connect the rod chamber and the rodless chamber of the lifting hydraulic cylinder Thereby increasing the pressure in the rodless chamber; the accumulator group is installed on the rodless chamber oil circuit, and the accumulator group is located between the system oil source and the connecting oil circuit; the first control structure is installed on the connecting oil circuit to control the on-off of the connecting oil circuit; the second control structure is installed on the rod chamber oil circuit, and is located between the oil tank and the connecting oil circuit, and the second control structure can limit the pressure oil on the rod chamber oil circuit to flow toward the oil tank; the proportional throttle valve is installed on the rodless chamber oil circuit, and the proportional throttle valve is located between the accumulator group and the connecting oil circuit.
[0006] Preferably, the first control structure includes: a first reversing valve and two first hydraulically controlled one-way valves; the two first hydraulically controlled one-way valves are installed on the connecting oil circuit, and the directions of the two first hydraulically controlled one-way valves are opposite; the A port of the first reversing valve is connected to the two first hydraulically controlled one-way valve control oil ports; the P port of the first reversing valve is connected to the rodless chamber oil circuit, and the T port of the first reversing valve is connected to the oil unloading port; the B port of the first reversing valve is closed.
[0007] Preferably, the second control structure includes: a second reversing valve and a second hydraulically controlled one-way valve; the second hydraulically controlled one-way valve is installed in the rod chamber oil circuit; and the second hydraulically controlled one-way valve flows in one direction toward the rod chamber of the lifting hydraulic cylinder; the A port of the second reversing valve is connected to the control oil port of the second hydraulically controlled one-way valve; the P port of the second reversing valve is connected to the rodless chamber oil circuit; the T port of the second reversing valve is connected to the oil unloading port; the B port of the second reversing valve is closed.
[0008] Preferably, it also includes an auxiliary descending structure, which includes: a variable pressure oil source, an oil supply circuit, a third one-way valve and a third reversing valve; the variable pressure oil source is connected to the rod chamber of the lifting hydraulic cylinder through the oil supply circuit to realize the control of the one-way variable pressure of the rod chamber of the lifting hydraulic cylinder; the third one-way valve is installed on the oil supply circuit, and the third one-way valve flows unidirectionally toward the rod chamber of the lifting hydraulic cylinder; the P port of the third reversing valve is connected to the variable pressure oil source; the A port of the third reversing valve is connected to the third one-way valve, the T port of the third reversing valve is connected to the oil tank, and the B port of the third reversing valve is closed.
[0009] Preferably, it also includes a first pressure sensor and a second pressure sensor installed on the rodless chamber oil circuit, the first pressure sensor is located at the proportional throttle valve A port close to the accumulator, and the second pressure sensor is located at the proportional throttle valve B port close to the connecting oil circuit.
[0010] Preferably, it also includes a balancing valve installed on the rodless chamber oil circuit, and the balancing valve is located between the proportional throttle valve and the connecting oil circuit.
[0011] Compared with the prior art, the utility model has at least the following advantages:
[0012] 1. In the utility model, when the lifting hydraulic cylinder descends under the action of a heavy object, the second control structure is used to limit the pressure oil from flowing toward the oil tank, and the first control structure is used to control the connecting oil circuit to be connected, so that the rodless chamber and the rod chamber of the lifting hydraulic cylinder are connected; the pressure of the connected rodless chamber is greater than the pressure of the system oil source; at this time, a part of the pressure oil in the rodless chamber of the lifting hydraulic cylinder flows into the rod chamber of the lifting hydraulic cylinder through the connecting oil circuit, and the other part flows into the accumulator group through the rodless chamber oil circuit, thereby realizing the recovery of the potential energy of the heavy object.
[0013] 2. In the utility model, when the potential energy of the heavy object itself is less than the pressure of the system oil source, the gravity of the heavy object is not enough to push the piston rod of the lifting hydraulic cylinder down; in this way, the third reversing valve can be controlled to be energized, so that the P port of the third reversing valve is connected to the A port, and the T port of the third reversing valve is connected to the B port; the pressure oil of the variable pressure oil source flows to the third check valve through the P port and the A port of the third reversing valve, and then flows to the rod chamber of the lifting hydraulic cylinder through the A port and the B port of the third check valve; thereby increasing the pressure of the rodless chamber of the lifting hydraulic cylinder, so that the pressure of the lifting hydraulic cylinder is greater than the pressure of the system oil source, and the proportional throttle valve realizes speed control while recovering energy to the accumulator group; in this way, the problem that the potential energy of the heavy object itself is less than the pressure of the system oil source can be solved, thereby realizing the recovery and reuse of gravity potential energy. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the specific implementation of the utility model, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.
[0015] Figure 1 This is a working principle diagram of an energy-saving hydraulic control system for a lifting mechanism provided in an embodiment of the utility model.
[0016] Figure markings: 1-lifting hydraulic cylinder, 2-rodless chamber oil circuit, 3-rod chamber oil circuit, 4-connecting oil circuit, 5-system oil source, 6-accumulator group, 7-first reversing valve, 8-first hydraulically controlled one-way valve, 9-second reversing valve, 10-second hydraulically controlled one-way valve, 11-variable pressure oil source, 12-oil supply circuit, 13-third one-way valve, 14-third reversing valve, 15-first pressure sensor, 16-second pressure sensor, 17-balancing valve, 18-proportional throttle valve. DETAILED DESCRIPTION
[0017] The following embodiments of the technical solution of the utility model are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and are therefore only used as examples, and cannot be used to limit the protection scope of the utility model.
[0018] In the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and 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 therefore should not be understood as a limitation on the present invention.
[0019] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0020] See also Figure 1 , the utility model provides an embodiment: an energy-saving hydraulic control system for a lifting mechanism, comprising: a lifting hydraulic cylinder 1, a rodless chamber oil circuit 2, a rod chamber oil circuit 3, a connecting oil circuit 4, a system oil source 5, an accumulator group 6, a first control structure, a second control structure and a proportional throttle valve 18; the rodless chamber of the lifting hydraulic cylinder 1 is connected to the system oil source 5 through the rodless chamber oil circuit 2; the rod chamber of the lifting hydraulic cylinder 1 is connected to the oil tank through the rod chamber oil circuit 3; the two ends of the connecting oil circuit 4 are respectively connected to the rod chamber oil circuit 3 and the rodless chamber oil circuit 2, so as to directly connect the rod chamber and the rodless chamber of the lifting hydraulic cylinder 1, thereby increasing the rodless chamber. The pressure of the rod chamber; the accumulator group 6 is installed on the rodless chamber oil circuit 2, and the accumulator group 6 is located between the system oil source 5 and the connecting oil circuit 4; the first control structure is installed on the connecting oil circuit 4 to control the on-off of the connecting oil circuit 4; the second control structure is installed on the rod chamber oil circuit 3, and is located between the oil tank and the connecting oil circuit 4, and the second control structure can limit the pressure oil on the rod chamber oil circuit 3 to flow toward the oil tank; the proportional throttle valve 18 is installed on the rodless chamber oil circuit 2, and the proportional throttle valve 18 is located between the accumulator group 6 and the balance valve 17; the lifting speed of the lifting hydraulic cylinder 1 is adjusted by the proportional throttle valve 18. Furthermore, it also includes a balance valve 17 installed on the rodless chamber oil circuit 2, and the balance valve 17 is located between the proportional throttle valve 18 and the connecting oil circuit 4; through the setting of the balance valve 17, the lifting hydraulic cylinder 1 can lock the position of the piston rod of the lifting hydraulic cylinder 1 when lifting heavy objects.
[0021] When it is necessary to lift heavy objects, the second control structure stops restricting the flow of pressure oil toward the oil tank. At this time, the rod chamber of the lifting hydraulic cylinder 1 is connected to the oil tank through the rod chamber oil circuit 3, reducing the back pressure of the lifting hydraulic cylinder 1; the first control structure controls the connection oil circuit 4 to be disconnected. At this time, the system oil source 5 is connected to the rodless chamber of the lifting hydraulic cylinder 1 through the rodless chamber oil circuit 2, and the system oil source 5 supplies oil to the rodless chamber of the lifting hydraulic cylinder 1, thereby pushing the piston on the lifting hydraulic cylinder 1 to move and lift heavy objects.
[0022] When the lifting hydraulic cylinder 1 descends under the action of a heavy object, the second control structure is used to limit the pressure oil from flowing toward the oil tank, and the first control structure is used to control the connecting oil circuit 4 to be connected, so that the rodless chamber and the rod chamber of the lifting hydraulic cylinder 1 are connected; the pressure of the connected rodless chamber increases due to the pressure of the rod chamber, and at this time the pressure of the rodless chamber is greater than the pressure of the system oil source 5; a part of the pressure oil in the rodless chamber of the lifting hydraulic cylinder 1 flows into the rodless chamber of the lifting hydraulic cylinder 1 through the connecting oil circuit 4, and the other part flows into the accumulator group 6 through the rodless chamber oil circuit 2 and the proportional throttle valve 18, thereby realizing the recovery of the potential energy of the heavy object.
[0023] See also Figure 1 In other embodiments, the first control structure includes: a first reversing valve 7 and two first hydraulically controlled one-way valves 8; the two first hydraulically controlled one-way valves 8 are installed on the connecting oil circuit 4, and the directions of the two first hydraulically controlled one-way valves 8 are opposite; the A port of the first reversing valve 7 is connected to the two first hydraulically controlled one-way valves 8 control oil ports; the P port of the first reversing valve 7 is connected to the rodless chamber oil circuit 2, and the T port of the first reversing valve 7 is connected to the oil unloading port; the B port of the first reversing valve 7 is closed.
[0024] During specific implementation, the B ports of the two first hydraulically controlled one-way valves 8 are connected to each other, the A port of one of the first hydraulically controlled one-way valves 8 is connected to the rod chamber oil circuit 3, and the A port of the other first hydraulically controlled one-way valve 8 is connected to the rodless chamber oil circuit 2; the first reversing valve 7 is a two-position four-way electromagnetic reversing valve; when the first reversing valve 7 is energized, the P port of the first reversing valve 7 is connected to the B port, and the T port of the first reversing valve 7 is connected to the A port; the pressure oil at the P port of the first reversing valve 7 stops flowing to the two first hydraulically controlled one-way valves 8 The control oil port supplies oil, and the two first hydraulically controlled one-way valves 8 are in a closed state, so that the two first hydraulically controlled one-way valves 8 can only flow in one direction; the first reversing valve 7 loses power, the P port of the first reversing valve 7 is connected to the A port, and the T port of the first reversing valve 7 is connected to the B port; the pressure oil at the P port of the first reversing valve 7 is supplied to the control oil ports of the two first hydraulically controlled one-way valves 8, and the two first hydraulically controlled one-way valves 8 are in an open state, so that the pressure oil at the two first hydraulically controlled one-way valves 8 can flow in two directions. In this way, the two first hydraulically controlled one-way valves 8 can be controlled by the first reversing valve 7 to achieve the purpose of controlling the connection oil circuit 4.
[0025] Furthermore, the first control structure may also be replaced by other valves that can achieve the shutoff function.
[0026] See also Figure 1 In other embodiments, the second control structure includes: a second reversing valve 9 and a second hydraulically controlled one-way valve 10; the second hydraulically controlled one-way valve 10 is installed on the rod chamber oil circuit 3; and the second hydraulically controlled one-way valve 10 flows in one direction toward the rod chamber of the lifting hydraulic cylinder 1; the A port of the second reversing valve 9 is connected to the control oil port of the second hydraulically controlled one-way valve 10; the P port of the second reversing valve 9 is connected to the rodless chamber oil circuit 2; the T port of the second reversing valve 9 is connected to the oil unloading port; and the B port of the second reversing valve 9 is closed.
[0027] During specific implementation, the A port of the second hydraulically controlled one-way valve is connected to the oil tank, and the B port of the second hydraulically controlled one-way valve is connected to the rod chamber of the lifting hydraulic cylinder 1; the second reversing valve 9 is a two-position four-way electromagnetic reversing valve; the second reversing valve 9 is energized, the P port of the second reversing valve 9 is connected to the A port, and the T port of the second reversing valve 9 is connected to the B port; the pressure oil at the P port of the second reversing valve 9 flows toward the control oil port of the second hydraulically controlled one-way valve 10, controlling the second hydraulically controlled one-way valve 10 to be in an open state, so that the pressure oil at the second hydraulically controlled one-way valve 10 can flow in both directions ; The pressure oil in the rod chamber of the lifting hydraulic cylinder 1 can flow to the oil tank through the second hydraulically controlled one-way valve 10; the second reversing valve 9 loses power, the P port of the second reversing valve 9 is connected to the B port, and the T port of the second reversing valve 9 is connected to the A port; the pressure oil at the P port of the second reversing valve 9 stops supplying oil to the control oil port of the second hydraulically controlled one-way valve 10, and the second hydraulically controlled one-way valve 10 is in a closed state, so that the second hydraulically controlled one-way valve 10 can only flow in one direction; the pressure oil in the rod chamber of the lifting hydraulic cylinder 1 cannot flow to the oil tank through the second hydraulically controlled one-way valve 10. In this way, the second hydraulically controlled one-way valve 10 can be controlled by the second reversing valve 9.
[0028] See also Figure 1 In other embodiments, an auxiliary descending structure is also included, and the auxiliary descending structure includes: a variable pressure oil source 11, an oil supply circuit 12, a third one-way valve 13 and a third reversing valve 14; the variable pressure oil source 11 is connected to the rod chamber of the lifting hydraulic cylinder 1 through the oil supply circuit 12 to realize the control of the one-way variable pressure of the rod chamber of the lifting hydraulic cylinder 1; the third one-way valve 13 is installed on the oil supply circuit 12, and the third one-way valve 13 flows in one direction toward the rod chamber of the lifting hydraulic cylinder 1; the P port of the third reversing valve 14 is connected to the variable pressure oil source 11; the A port of the third reversing valve 14 is connected to the third one-way valve 13, the T port of the third reversing valve 14 is connected to the oil tank, and the B port of the third reversing valve 14 is closed.
[0029] In specific implementation, the A port of the third one-way valve 13 is connected to the A port of the third reversing valve 14, and the B port of the third one-way valve 13 is connected to the rod chamber of the lifting hydraulic cylinder 1; the third reversing valve 14 is a two-position four-way electromagnetic reversing valve;
[0030] When the third reversing valve 14 is energized, the P port of the third reversing valve 14 is connected to the A port, and the T port of the third reversing valve 14 is connected to the B port; the pressure oil of the variable pressure oil source 11 flows to the third check valve 13 through the P port and the A port of the third reversing valve 14, and then flows to the rod chamber of the lifting hydraulic cylinder 1 through the A port and the B port of the third check valve 13; thereby increasing the pressure of the rodless chamber of the lifting hydraulic cylinder 1, so that the pressure of the lifting hydraulic cylinder 1 is greater than the pressure of the system oil source 5; in this way, the problem that the potential energy of the heavy object itself is less than the pressure of the system oil source 5 can be solved. At the same time, the pressure oil on the rod chamber oil circuit 3 is restricted from flowing toward the oil tank through the second control structure.
[0031] When the third reversing valve 14 is selected to be controlled to lose power, the P port of the third reversing valve 14 is connected to the B port, and the T port of the third reversing valve 14 is connected to the A port; so that the oil supply circuit 12 is disconnected, so that the variable pressure oil source 11 can stop supplying oil to the rod chamber of the lifting hydraulic cylinder 1.
[0032] See also Figure 1 In another embodiment, the pump realizes unidirectional variable pressure control on the rod chamber of the lifting hydraulic cylinder 1; it also includes a first pressure sensor 15 and a second pressure sensor 16 installed on the rodless chamber oil circuit 2, the first pressure sensor 15 is located at the A port of the proportional throttle valve 18 close to the accumulator, and the second pressure sensor 16 is located at the B port of the proportional throttle valve 18 close to the connecting oil circuit 4.
[0033] During specific implementation, the pressure on the rodless chamber oil circuit 2 near the accumulator group 6 is measured by the first sensor, and the pressure near the connecting oil circuit 4 is measured by the second oil source; in the process of the heavy object pushing the piston rod of the lifting hydraulic cylinder 1 to descend, the pressure of the variable pressure oil source 11 is adjusted by the pressure measured by the first pressure sensor 15 and the second pressure sensor 16, so that the pressure at the second pressure sensor 16 is always greater than the pressure at the first pressure sensor 15 by 10-15bar; in this way, the variable pressure control of the variable pressure oil source 11 makes the control system have no unnecessary pressure consumption and has sufficient pressure difference, so that the lifting hydraulic cylinder 1 is smoothly controlled.
[0034] The working principle and use process of this utility model:
[0035] When heavy objects need to be lifted:
[0036] The first reversing valve 7 is controlled to be energized, the P port of the first reversing valve 7 is connected to the B port, and the T port of the first reversing valve 7 is connected to the A port; the pressure oil at the P port of the first reversing valve 7 stops supplying oil to the control oil ports of the two first hydraulically controlled one-way valves 8, and the two first hydraulically controlled one-way valves 8 are in a closed state; so that the connecting oil circuit 4 is disconnected.
[0037] Then control the second reversing valve 9 to be energized, the P port of the second reversing valve 9 is connected to the A port, and the T port of the second reversing valve 9 is connected to the B port; the pressure oil at the P port of the second reversing valve 9 flows toward the control oil port of the second hydraulically controlled one-way valve 10, and the second hydraulically controlled one-way valve 10 is controlled to be in an open state, so that the pressure oil at the second hydraulically controlled one-way valve 10 can flow in both directions; the pressure oil in the rod chamber of the lifting hydraulic cylinder 1 can flow to the oil tank through the second hydraulically controlled one-way valve 10; at this time, there is no back pressure in the rod chamber of the lifting hydraulic cylinder 1.
[0038] Then, the third reversing valve 14 is controlled to lose power, the P port of the third reversing valve 14 is connected to the B port, and the T port of the third reversing valve 14 is connected to the A port; so that the oil supply circuit 12 is disconnected, so that the variable pressure oil source 11 can stop supplying oil to the rod chamber of the lifting hydraulic cylinder 1.
[0039] In this way, the system oil source 5 can supply oil to the rodless chamber of the lifting hydraulic cylinder 1 through the proportional throttle valve 18, pushing the piston rod of the lifting hydraulic cylinder 1 to rise, thereby lifting the heavy object.
[0040] When the lifting hydraulic cylinder 1 descends under the action of a heavy object, the first energy recovery mode can be selected:
[0041] The first reversing valve 7 is controlled to lose power, the P port of the first reversing valve 7 is connected to the A port, and the T port of the first reversing valve 7 is connected to the B port; the pressure oil at the P port of the first reversing valve 7 is supplied to the control oil ports of the two first hydraulically controlled one-way valves 8, and the two first hydraulically controlled one-way valves 8 are in an open state, so that the pressure oil at the two first hydraulically controlled one-way valves 8 can flow in both directions.
[0042] Then control the second reversing valve 9 to lose power, the P port of the second reversing valve 9 is connected to the B port, and the T port of the second reversing valve 9 is connected to the A port; the pressure oil at the P port of the second reversing valve 9 stops supplying oil to the control oil port of the second hydraulically controlled one-way valve 10, and the second hydraulically controlled one-way valve 10 is in a closed state, so that the second hydraulically controlled one-way valve 10 can only flow in one direction; the pressure oil in the rod chamber of the lifting hydraulic cylinder 1 cannot flow to the oil tank through the second hydraulically controlled one-way valve 10.
[0043] Then control the third reversing valve 14 to lose power, the P port of the third reversing valve 14 is connected to the B port, and the T port of the third reversing valve 14 is connected to the A port; so that the oil supply circuit 12 is disconnected, and the variable pressure oil source 11 can stop supplying oil to the rod chamber of the lifting hydraulic cylinder 1.
[0044] In this way, the rodless chamber and the rod chamber of the lifting hydraulic cylinder 1 are connected; the pressure of the connected rodless chamber increases due to the pressure of the rod chamber, and at this time the pressure of the rodless chamber is greater than the pressure of the system oil source 5; a part of the pressure oil in the rodless chamber of the lifting hydraulic cylinder 1 flows into the rodless chamber of the lifting hydraulic cylinder 1 through the connecting oil circuit 4, and the other part flows into the accumulator group 6 through the rodless chamber oil circuit 2 and the proportional throttle valve 18, thereby realizing the recovery of the potential energy of the heavy object.
[0045] When the lifting hydraulic cylinder 1 descends under the action of a heavy object, a second energy recovery mode can also be selected:
[0046] The first reversing valve 7 is controlled to be energized, the P port of the first reversing valve 7 is connected to the B port, and the T port of the first reversing valve 7 is connected to the A port; the pressure oil at the P port of the first reversing valve 7 stops supplying oil to the control oil ports of the two first hydraulically controlled one-way valves 8, and the two first hydraulically controlled one-way valves 8 are in a closed state. The two first hydraulically controlled one-way valves 8 can only flow in one direction, so that the connecting oil circuit 4 is disconnected.
[0047] Then control the second reversing valve 9 to lose power, the P port of the second reversing valve 9 is connected to the B port, and the T port of the second reversing valve 9 is connected to the A port; the pressure oil at the P port of the second reversing valve 9 stops supplying oil to the control oil port of the second hydraulically controlled one-way valve 10, and the second hydraulically controlled one-way valve 10 is in a closed state, so that the second hydraulically controlled one-way valve 10 can only flow in one direction; the pressure oil in the rod chamber of the lifting hydraulic cylinder 1 cannot flow to the oil tank through the second hydraulically controlled one-way valve 10.
[0048] The third reversing valve 14 is controlled to be energized, so that the P port of the third reversing valve 14 is connected to the B port, and the T port of the third reversing valve 14 is connected to the A port; the pressure oil of the variable pressure oil source 11 flows to the third check valve 13 through the P port and the A port of the third reversing valve 14, and then flows to the rod chamber of the lifting hydraulic cylinder 1 through the A port and the B port of the third check valve 13; thereby increasing the pressure of the rodless chamber of the lifting hydraulic cylinder 1, so that the pressure of the lifting hydraulic cylinder 1 is greater than the pressure of the system oil source 5; in this way, the problem that the potential energy of the heavy object itself is less than the pressure of the system oil source 5 can be solved.
[0049] At this time, the pressure on the rodless chamber oil circuit 2 near the accumulator group 6 is measured by the first sensor, and the pressure near the connecting oil circuit 4 is measured by the second oil source; in the process of the heavy object pushing the piston rod of the lifting hydraulic cylinder 1 to descend, the pressure of the variable pressure oil source 11 is adjusted by the pressure measured by the first pressure sensor 15 and the second pressure sensor 16, so that the pressure at the second pressure sensor 16 is always greater than the pressure at the first pressure sensor 15 by 10-15bar; in this way, the variable pressure control of the variable pressure oil source 11 makes the control system have no unnecessary pressure consumption, and there is sufficient pressure difference, so that the lifting hydraulic cylinder 1 is smoothly controlled.
[0050] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.
Claims
1. An energy-saving hydraulic control system for a lifting mechanism, characterized in that: include: A lifting hydraulic cylinder, a rod chamber oil circuit, a rodless chamber oil circuit, a connecting oil circuit, a system oil source, an accumulator group, a first control structure, a second control structure and a proportional throttle valve; the rodless chamber of the lifting hydraulic cylinder is connected to the system oil source through the rodless chamber oil circuit; the rod chamber of the lifting hydraulic cylinder is connected to the oil tank through the rod chamber oil circuit; the two ends of the connecting oil circuit are respectively connected to the rod chamber oil circuit and the rodless chamber oil circuit to directly connect the rod chamber and the rodless chamber of the lifting hydraulic cylinder to increase the pressure of the rodless chamber; the accumulator group is installed on the rodless chamber oil circuit, and the accumulator group is located between the system oil source and the connecting oil circuit; the first control structure is installed on the connecting oil circuit to control the on-off of the connecting oil circuit; the second control structure is installed on the rod chamber oil circuit, and is located between the oil tank and the connecting oil circuit, and the second control structure can limit the pressure oil on the rod chamber oil circuit to flow toward the oil tank; the proportional throttle valve is installed on the rodless chamber oil circuit, and the proportional throttle valve is located between the accumulator group and the connecting oil circuit.
2. The energy-saving hydraulic control system for a lifting mechanism according to claim 1 is characterized in that: The first control structure includes: a first reversing valve and two first hydraulically controlled one-way valves; the two first hydraulically controlled one-way valves are installed on the connecting oil circuit, and the directions of the two first hydraulically controlled one-way valves are opposite; the A port of the first reversing valve is connected to the two first hydraulically controlled one-way valve control oil ports; the P port of the first reversing valve is connected to the rodless chamber oil circuit, and the T port of the first reversing valve is connected to the oil unloading port; the B port of the first reversing valve is closed.
3. The energy-saving hydraulic control system for a lifting mechanism according to claim 1 is characterized in that: The second control structure includes: a second reversing valve and a second hydraulically controlled one-way valve; the second hydraulically controlled one-way valve is installed on the rod chamber oil circuit; and the second hydraulically controlled one-way valve flows in one direction toward the rod chamber of the lifting hydraulic cylinder; the A port of the second reversing valve is connected to the control oil port of the second hydraulically controlled one-way valve; the P port of the second reversing valve is connected to the rodless chamber oil circuit; the T port of the second reversing valve is connected to the oil unloading port; the B port of the second reversing valve is closed.
4. The energy-saving hydraulic control system for a lifting mechanism according to claim 1 is characterized in that: It also includes an auxiliary descending structure, which includes: a variable pressure oil source, an oil supply circuit, a third one-way valve and a third reversing valve; the variable pressure oil source is connected to the rod chamber of the lifting hydraulic cylinder through the oil supply circuit to realize the control of the one-way variable pressure of the rod chamber of the lifting hydraulic cylinder; the third one-way valve is installed on the oil supply circuit, and the third one-way valve flows unidirectionally toward the rod chamber of the lifting hydraulic cylinder; the P port of the third reversing valve is connected to the variable pressure oil source; the A port of the third reversing valve is connected to the third one-way valve, the T port of the third reversing valve is connected to the oil tank, and the B port of the third reversing valve is closed.
5. The energy-saving hydraulic control system for a lifting mechanism according to claim 4 is characterized in that: It also includes a first pressure sensor and a second pressure sensor installed on the rodless chamber oil circuit, the first pressure sensor is located at the proportional throttle valve A port close to the accumulator, and the second pressure sensor is located at the proportional throttle valve B port close to the connecting oil circuit.
6. The energy-saving hydraulic control system for a lifting mechanism according to claim 1 is characterized in that: It also includes a balancing valve installed on the rodless chamber oil circuit, wherein the balancing valve is located between the proportional throttle valve and the connecting oil circuit.