Hydraulic system and working machine

Abstract

The hydraulic system comprises a first working link, a second working link, a first oil source and a second oil source. The first working link and the second working link are connected in parallel and each comprises a reversing valve and a pressure compensation valve. The outlet of the pressure compensation valve is connected with an actuator of the engineering machinery through the reversing valve. The pressure compensation valve has a first control end and a second control end. The first control end and the second control end control the pressure compensation valve to switch to a first valve position and a second valve position respectively. When in the first valve position, the inlet and the outlet of the pressure compensation valve are disconnected. When in the second valve position, the inlet and the outlet of the pressure compensation valve are connected. The first oil source is connected with the inlets of the pressure compensation valves of the first working link and the second working link. The second oil source is connected with an oil path between the reversing valve and the pressure compensation valve of the first working link. Thus, the problem that the light and heavy load actuators cannot work synchronously when the flow of the hydraulic system adopting the valve front compensation mode is saturated can be effectively solved.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a hydraulic system and engineering machinery. Background Technology

[0002] Some hydraulic systems of construction machinery include at least two working links connected in parallel, and each working link includes a directional valve and a pressure compensation valve. The pressure compensation valve is located before the directional valve and is connected to the actuator of the construction machinery through the directional valve to perform pressure compensation and maintain a constant pressure difference across the valve.

[0003] In the aforementioned hydraulic system of the related technology, when the actuators of different working links operate simultaneously and the required flow exceeds the pump's oil supply flow (i.e., flow saturation), the hydraulic oil usually flows to the light-load working link first, and only flows to other working links after satisfying the light-load working link. In this case, only the low-pressure actuator can be compensated and operate, while the actuator with a larger load slows down or even stops, causing the actuators of each working link to not operate synchronously, affecting the normal operation of the construction machinery. Summary of the Invention

[0004] This application provides a hydraulic system and engineering machinery to solve the problem that in a hydraulic system with a pressure compensation valve before the directional valve, the light and heavy load actuators cannot work synchronously when the flow is saturated.

[0005] The hydraulic system provided in this application includes:

[0006] The working system includes a first working link and a second working link, which are arranged in parallel. Each working link includes a directional valve and a pressure compensation valve. The outlet of the pressure compensation valve is connected to the actuator of the construction machinery via the directional valve to drive the actuator. The pressure compensation valve has a first control end and a second control end, which respectively control the pressure compensation valve to switch to a first valve position and a second valve position. When in the first valve position, the inlet and outlet of the pressure compensation valve are disconnected; when in the second valve position, the inlet and outlet of the pressure compensation valve are connected.

[0007] The oil supply system includes a first oil source and a second oil source. The first oil source is connected to the inlet of the pressure compensation valve of both the first and second working links. The second oil source is connected to the oil circuit between the directional valve and the pressure compensation valve of the first working link.

[0008] In some embodiments, the oil supply system further includes a first oil supply control system, which is used to lead the higher pressure of the first oil source and the second oil source to the first control terminal and / or the second control terminal of the pressure compensation valve of the first working link, so as to control the pressure compensation valve of the first working link to switch to the first valve position or the second valve position.

[0009] In some embodiments, the first oil supply control system comprises a comparison device connected to both the first oil source and the second oil source, and the first oil supply control system further comprises at least one of:

[0010] a first regulating valve connected to the comparison device and the first control end of the pressure compensator valve of the first working link, and controlling whether the comparison device and the first control end of the pressure compensator valve of the first working link are in communication, so as to control whether the one of the first oil source and the second oil source with higher pressure compared by the comparison device is introduced to the first control end of the pressure compensator valve of the first working link;

[0011] a second regulating valve connected to the comparison device and the second control end of the pressure compensator valve of the first working link, and controlling whether the comparison device and the first control end of the pressure compensator valve of the first working link are in communication, so as to control whether the one of the first oil source and the second oil source with higher pressure compared by the comparison device is introduced to the second control end of the pressure compensator valve of the first working link.

[0012] In some embodiments, the comparison device comprises a shuttle valve, two inlets of the shuttle valve are connected to the first oil source and the second oil source respectively, and an outlet of the shuttle valve is connected to the first regulating valve and / or the second regulating valve.

[0013] In some embodiments, the first regulating valve comprises a first valve port, a second valve port and a third valve port, the first valve port is connected to the comparison device, the second valve port is connected to a drain port of the hydraulic system, the third valve port is connected to the first control end of the pressure compensator valve of the first working link and is in switching communication with the first valve port and the second valve port, so as to control whether the comparison device and the first control end of the pressure compensator valve of the first working link are in communication; and / or, the second regulating valve comprises a first oil port, a second oil port and a third oil port, the first oil port is connected to the comparison device, the second oil port is connected to an oil path between the directional valve of the first working link and the actuator of the engineering machinery, the third oil port is connected to the second control end of the pressure compensator valve of the first working link and is in switching communication with the first oil port and the second oil port, so as to control whether the comparison device and the second control end of the pressure compensator valve of the first working link are in communication.

[0014] In some embodiments, the first regulating valve and / or the second regulating valve is an electrically controlled valve.

[0015] In some embodiments, the first regulating valve is a proportional pressure reducing valve.

[0016] In some embodiments, the oil path between the second oil source and the directional valve and the pressure compensator valve of the first working link is connected through a first one-way valve, so that the oil flows in a one-way direction from the second oil source to the directional valve of the first working link.

[0017] In some embodiments, the working system further comprises a third working link, the third working link is arranged in parallel with the first working link and the second working link, and comprises a reversing valve and a pressure compensation valve; the oil supply system further comprises a third oil source and a first merging link, the third oil source is connected with an inlet of the pressure compensation valve of the third working link, the first merging link is arranged between the second working link and the third working link, and connects the first oil source and the third oil source, and controls whether the first oil source and the third oil source are merged.

[0018] In some embodiments, the working system further comprises a fourth working link, and the oil supply system further comprises a fourth oil source, the fourth working link is arranged in parallel with the third working link, and comprises a reversing valve and a pressure compensation valve, an inlet of the pressure compensation valve of the fourth working link is connected with the third oil source, an oil path between the pressure compensation valve and the reversing valve of the fourth working link is connected with the fourth oil source, and the fourth oil source and the third oil source are connected with a first control end and / or a second control end of the pressure compensation valve of the fourth working link through a second oil supply control system, the second oil supply control system is used to guide the one with higher pressure between the third oil source and the fourth oil source to the first control end and / or the second control end of the pressure compensation valve of the fourth working link, so as to control the pressure compensation valve of the fourth working link to switch to the first valve position or the second valve position.

[0019] In some embodiments, the working system further comprises a fifth working link, the fifth working link is arranged in parallel with the fourth working link, and comprises a reversing valve and a pressure compensation valve, the third oil source is connected with an inlet of the pressure compensation valve of the fifth working link, and is connected with inlets of the pressure compensation valves of the fourth working link and the third working link through a second merging link, the second merging link is arranged between the fourth working link and the fifth working link, and controls whether the first oil source and the third oil source are connected.

[0020] In addition, the engineering machinery provided in the present application comprises the hydraulic system of any one of the embodiments of the present application.

[0021] In the present application, the hydraulic system no longer comprises only one oil source, but comprises a first oil source and a second oil source, and the first oil source is connected with inlets of the pressure compensation valves of the first working link and the second working link, and the second oil source is connected with an oil path between the reversing valve and the pressure compensation valve of the first working link, so that when the first working link and the second working link are compounded, the first working link can be supplied with oil by the second oil source, and the second working link can be supplied with oil by the first oil source, so that the first working link and the second working link can be supplied with oil by different oil sources, preventing the system flow from flowing preferentially to the low-load actuator due to sharing the same oil source, and causing the phenomenon of asynchronization of the compound action, effectively solving the problem that the light and heavy load actuators cannot work synchronously when the hydraulic system adopting the valve front compensation mode is saturated in flow.

[0022] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative effort based on these drawings.

[0024] Figure 1 The hydraulic principle diagram of the hydraulic system in the first embodiment of the present application.

[0025] Figure 2 The hydraulic principle diagram of the hydraulic system in the second embodiment of the present application.

[0026] Figure 3 The hydraulic principle diagram of the hydraulic system in the third embodiment of the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 100, hydraulic system; 10, working system; 101, first working link; 102, second working link; 103, third working link; 104, fourth working link; 105, fifth working link; 20, oil supply system;

[0029] 1, reversing control valve;

[0030] 2, reversing valve;

[0031] 3, pressure compensation valve; 31, first control end; 32, second control end;

[0032] 4, first check valve;

[0033] 5, first oil supply control system; 51, first regulating valve; 52, second regulating valve; 53, comparison device; 54, shuttle valve;

[0034] 6, first merging link; 61, merging valve; 62, merging control valve;

[0035] 7, feedback device; 71, second check valve;

[0036] 8, second oil supply control system;

[0037] 9, second merging link;

[0038] P1, first oil source; P2, second oil source; P3, third oil source; T, oil return port; L, oil drain port; Ls, load-sensitive feedback oil port. DETAILED DESCRIPTION

[0039] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The following description of at least one example embodiment is merely illustrative in nature and does not limit the application or its application or use in any way. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0040] The technologies, methods and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification when appropriate.

[0041] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0042] In the description of the present application, it should be understood that the use of "first", "second" and the like to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated. Therefore, it cannot be understood as a limitation on the scope of protection of the present application.

[0043] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0044] Generally, the way of setting a pressure compensation valve in front of the reversing valve is called pre-valve compensation.

[0045] In the related art, in the hydraulic system adopting the pre-valve compensation mode, each working connection is supplied with oil by the same oil source. However, due to the fact that in the parallel oil circuit, hydraulic oil will preferentially flow to the actuator with lower load (which can be simply referred to as the light load side), when the flow is insufficient, the actuator with higher load (which can be simply referred to as the heavy load side) cannot obtain sufficient flow, so it cannot play a compensation role. This will lead to the situation that when the flow is saturated, the actuators of the composite action cannot act synchronously, which affects the normal work of the engineering machinery.

[0046] In order to solve the problem that the light and heavy load actuators cannot work synchronously when the flow of the hydraulic system adopting the valve pre-compensation mode is saturated, the application provides a hydraulic system.

[0047] Figures 1-3 The structure of the hydraulic system in the application is exemplarily shown.

[0048] Referring to Figures 1-3 In the application, the hydraulic system 100 comprises a working system 10 and an oil supply system 20.

[0049] The working system 10 comprises a first working link 101 and a second working link 102. The first working link 101 and the second working link 102 are arranged in parallel and each comprises a reversing valve 2 and a pressure compensation valve 3. The outlet of the pressure compensation valve 3 is connected to the actuator (not shown) of the engineering machinery through the reversing valve 2 to drive the actuator to act. The pressure compensation valve 3 has a first control end 31 and a second control end 32. The first control end 31 and the second control end 32 control the pressure compensation valve 3 to switch to the first valve position and the second valve position respectively. When in the first valve position, the inlet and the outlet of the pressure compensation valve 3 are disconnected. When in the second valve position, the inlet and the outlet of the pressure compensation valve 3 are communicated.

[0050] The oil supply system 20 comprises a first oil source P1 and a second oil source P2. The first oil source P1 is connected to the inlets of the pressure compensation valves 3 of the first working link 101 and the second working link 102. The second oil source P2 is connected to the oil path between the reversing valve 2 and the pressure compensation valve 3 of the first working link 101.

[0051] In the above scheme, the hydraulic system 10 still adopts the valve pre-compensation mode, but it no longer comprises only one oil source, but comprises the first oil source P1 and the second oil source P2. The first oil source P1 is connected to the inlets of the pressure compensation valves 3 of the first working link 101 and the second working link 102. The second oil source P2 is connected to the oil path between the reversing valve 2 and the pressure compensation valve 3 of the first working link 101. In this way, when the first working link 101 and the second working link 102 act in combination, the second oil source P2 can supply oil to the first working link 101, and the first oil source P1 can supply oil to the second working link 102. The first working link 101 and the second working link 102 can be supplied with oil by different oil sources, so that even in the case of flow saturation, the first working link 101 and the second working link 102 can obtain the required flow respectively, act synchronously, and prevent the phenomenon that the system flow preferentially flows to the low load actuator due to sharing the same oil source, resulting in the asynchronization of the combined action. The problem that the light and heavy load actuators cannot work synchronously when the flow of the hydraulic system adopting the valve pre-compensation mode is saturated is effectively solved, and the stability of the combined action is improved.

[0052] Further, referring to Figures 1-3In some embodiments, the oil supply system 20 not only comprises the first oil source P1 and the second oil source P2, but also comprises a first oil supply control system 5 for leading the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 and / or the second control end 32 of the pressure compensating valve 3 of the first working link 101, so as to control the pressure compensating valve 3 of the first working link 101 to switch to the first valve position or the second valve position.

[0053] When the first oil supply control system 5 leads the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 of the pressure compensating valve 3 of the first working link 101, the first oil supply control system 5 can control the pressure compensating valve 3 of the first working link 101 to switch to the first valve position, so that the inlet and the outlet of the pressure compensating valve 3 of the first working link 101 are disconnected, and the pressure oil provided by the first oil source P1 can no longer flow to the reversing valve 2 through the pressure compensating valve 3 of the first working link 101, which can make the first working link 101 not obtain pressure oil from the first oil source P1 when the first working link 101 and the second working link 102 composite action, so as to make the first working link 101 and the second working link 102 obtain pressure oil from the second oil source P2 and the first oil source P1 respectively, in which case, the first working link 101 and the second working link 102 are supplied by independent oil sources and do not interfere with each other, which is more conducive to improving the stability of composite action. Of course, if the first oil supply control system 5 is not arranged to lead the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 of the pressure compensating valve 3 of the first working link 101, or although the first oil supply control system 5 is arranged to lead the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 of the pressure compensating valve 3 of the first working link 101, but the first oil supply control system 5 does not lead the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 of the pressure compensating valve 3 of the first working link 101 when the first working link 101 and the second working link 102 composite action, then the first oil source P1 not only supplies oil to the second working link 102, but also supplies oil to the first working link 101 during composite action, at this time, the first working link 101 can not only obtain pressure oil from the second oil source P2, but also obtain pressure oil from the first oil source P1, that is, the first oil source P1 and the second oil source P2 together supply oil to the first working link 101, which is conducive to improving the working speed of the first working link 101 and meeting the demand of the first working link 101 for higher working speed.

[0054] When the first oil supply control system 5 leads the one with higher pressure between the first oil source P1 and the second oil source P2 to the second control end 32 of the pressure compensation valve 3 of the first working link 101, the first oil supply control system 5 can control the pressure compensation valve 3 of the first working link 101 to switch to the second valve position, so that the inlet and the outlet of the pressure compensation valve 3 of the first working link 101 are communicated, and the second oil source P2 is communicated with the first oil source P1. This can make the second working link 102 act alone, not only the first oil source P1 can supply oil to the second working link 102, but also the pressure oil provided by the second oil source P2 can flow reversely through the pressure compensation valve 3 of the first working link 101 (i.e. from the outlet of the pressure compensation valve 3 to the inlet of the pressure compensation valve 3), and combine with the pressure oil provided by the first oil source P1 to flow to the second working link 102, so as to supply oil to the second working link 102. That is, the first oil source P1 and the second oil source P2 can supply oil to the second working link 102 acting alone together. In this way, the working speed of the second working link 102 can be improved, and the demand of the second working link 102 for higher working speed can be met.

[0055] It can be seen that by setting the first oil supply control system 5, not only can the problem that the light and heavy load actuators cannot work synchronously when the flow of the hydraulic system adopting the valve pre-compensation mode is saturated be effectively solved, and the stability of the composite action be improved, but also the requirements of different working links for different working speeds can be met, the working flexibility can be improved, and the adaptability of the hydraulic system 100 to different working conditions can be improved.

[0056] As an example of the above-mentioned first oil supply control system 5, refer to Figures 1-3 The first oil supply control system 5 comprises a comparison device 53 connected with the first oil source P1 and the second oil source P2, and the first oil supply control system 5 further comprises at least one of the following:

[0057] A first regulating valve 51 connected with the comparison device 53 and the first control end 31 of the pressure compensation valve 3 of the first working link 101, and controls whether the comparison device 53 and the first control end 31 of the pressure compensation valve 3 of the first working link 101 are communicated, so as to control whether the one with higher pressure between the first oil source P1 and the second oil source P2 compared by the comparison device 53 is led to the first control end 31 of the pressure compensation valve 3 of the first working link 101;

[0058] A second regulating valve 52 connected with the comparison device 53 and the second control end 32 of the pressure compensation valve 3 of the first working link 101, and controls whether the comparison device 53 and the first control end 31 of the pressure compensation valve 3 of the first working link 101 are communicated, so as to control whether the one with higher pressure between the first oil source P1 and the second oil source P2 compared by the comparison device 53 is led to the second control end 32 of the pressure compensation valve 3 of the first working link 101.

[0059] In the above scheme, the comparison device 53 is configured to compare the pressures of the first oil source P1 and the second oil source P2, and output the higher pressure of the first oil source P1 and the second oil source P2 obtained by comparison, the first regulating valve 51 is configured to control whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the first control end 31 of the pressure compensation valve 3 of the first working link 101, and the second regulating valve 52 is configured to control whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the second control end 32 of the pressure compensation valve 3 of the first working link 101. In this way, the comparison device 53 and the first regulating valve 51 can be combined to control whether the higher pressure of the first oil source P1 and the second oil source P2 is introduced to the first control end 31 of the pressure compensation valve 3 of the first working link 101, and further control whether the first oil source P1 supplies oil to the first working link 101 through the pressure compensation valve 3 of the first working link 101, so as to flexibly meet the demand of the first working link 101 for different working speeds. In addition, the comparison device 53 and the second regulating valve 52 can be combined to control whether the higher pressure of the first oil source P1 and the second oil source P2 is introduced to the second control end 32 of the pressure compensation valve 3 of the first working link 101, and further control whether the second oil source P2 flows together with the first oil source P1 to supply oil to the second working link 102, so as to flexibly meet the demand of the second working link 102 for different working speeds.

[0060] In order to enable the comparison device 53 to compare and output the higher pressure of the first oil source P1 and the second oil source P2, see Figures 1-3 In some embodiments, the comparison device 53 comprises a shuttle valve 54, two inlets of the shuttle valve 54 are connected with the first oil source P1 and the second oil source P2 respectively, and an outlet of the shuttle valve 54 is connected with the first regulating valve 51 and / or the second regulating valve 52. Based on this, the shuttle valve 54 can compare the pressures of the first oil source P1 and the second oil source P2, and output the higher pressure of the first oil source P1 and the second oil source P2 obtained by comparison to the first regulating valve 51 and / or the second regulating valve 52, so as to control whether the higher pressure of the first oil source P1 and the second oil source P2 is introduced to the first control end 31 and / or the second control end 32 of the pressure compensation valve 3 of the first working link 101 by the first regulating valve 51 and / or the second regulating valve 52. At this time, the comparison device 53 has a simple structure and is convenient to control.

[0061] In addition, in order to enable the first regulating valve 51 to control whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the first control end 31 of the pressure compensation valve 3 of the first working link 101, see Figures 1-3In some embodiments, the first regulating valve 51 comprises a first valve port, a second valve port and a third valve port, the first valve port is connected with the comparison device 53, the second valve port is connected with the oil drain port L of the hydraulic system 100, the third valve port is connected with the first control end 31 of the pressure compensation valve 3 of the first working connection 101 and is in switching communication with the first valve port and the second valve port to control whether the comparison device 53 is in communication with the first control end 31 of the pressure compensation valve 3 of the first working connection 101. In this way, by controlling the third valve port of the first regulating valve 51 to be in communication with one of the first valve port and the second valve port and the other to be disconnected, whether the comparison device 53 is in communication with the first control end 31 of the pressure compensation valve 3 of the first working connection 101 can be controlled, and in turn whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the first control end 31 of the pressure compensation valve 3 of the first working connection 101 can be controlled. The first regulating valve 51 can be a hydraulic control valve, a manually controlled valve or an electrically controlled valve. When the first regulating valve 51 is an electrically controlled valve, the control is more convenient and accurate. In addition, the first regulating valve 51 can be a proportional valve, specifically, a proportional pressure reducing valve, so that the first regulating valve 51 can not only control whether the pressure compensation valve 3 of the first working connection 101 is switched to the first valve position, but also control the opening degree of the pressure compensation valve 3 of the first working connection 101 to more finely adjust the oil supply amount of the first oil source P1 to the first working connection 101, to meet more various speed requirements of the first working connection 101.

[0062] In order to enable the second regulating valve 52 to control whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the second control end 32 of the pressure compensation valve 3 of the first working connection 101, referring to Figures 1-3 In some embodiments, the second regulating valve 52 comprises a first oil port, a second oil port and a third oil port, the first oil port is connected with the comparison device 53, the second oil port is connected with the oil path between the directional valve 2 of the first working connection 101 and the actuator of the engineering machinery, the third oil port is connected with the second control end 32 of the pressure compensation valve 3 of the first working connection 101 and is in switching communication with the first oil port and the second oil port to control whether the comparison device 53 is in communication with the second control end 32 of the pressure compensation valve 3 of the first working connection 101. In this way, by controlling the third oil port of the second regulating valve 52 to be in communication with one of the first oil port and the second oil port and the other to be disconnected, whether the comparison device 53 is in communication with the second control end 32 of the pressure compensation valve 3 of the first working connection 101 can be controlled, and in turn whether the higher pressure of the first oil source P1 and the second oil source P2 output by the comparison device 53 is introduced to the second control end 32 of the pressure compensation valve 3 of the first working connection 101 can be controlled. The second regulating valve 52 can be a hydraulic control valve, a manually controlled valve or an electrically controlled valve. When the second regulating valve 52 is an electrically controlled valve, the control is more convenient and accurate.

[0063] In the foregoing embodiments, the working system 10 is not limited to only including the first working link 101 and the second working link 102, but can also include more working links.

[0064] For example, referring to Figures 1-3 In some embodiments, the working system 10 not only includes the first working link 101 and the second working link 102, but also includes a third working link 103, which is arranged in parallel with the first working link 101 and the second working link 102, and includes the reversing valve 2 and the pressure compensation valve 3, and the oil supply system 20 further includes a third oil source P3 and a first merging link 6, the third oil source P3 is connected with the inlet of the pressure compensation valve 3 of the third working link 103, and is connected with the first oil source P1 through the first merging link 6, and the first merging link 6 controls whether the first oil source P1 and the third oil source P3 are merged.

[0065] Based on the above scheme, when two or three of the first working link 101, the second working link 102 and the third working link 103 perform composite action, the second oil source P2 can supply oil to the first working link 101, the first oil source P1 can supply oil to the second working link 102, and the third oil source P3 can supply oil to the third working link 103, so that the first working link 101, the second working link 102 and the third working link 103 can be supplied by different oil sources, thereby even when two or three of the first working link 101, the second working link 102 and the third working link 103 perform composite action in the case of flow saturation, the required flow of the two or three working links can be obtained respectively, synchronous action can be achieved, and the phenomenon that the system flow preferentially flows to the low-load actuator when sharing the same oil source can be prevented, effectively solving the problem that the light and heavy load actuators cannot work synchronously in the hydraulic system using the pre-valve compensation method in the case of flow saturation, and improving the stability of composite action.

[0066] Moreover, since the first merging link 6 is arranged to connect the first oil source P1 and the third oil source P3 and control whether the first oil source P1 and the third oil source P3 are merged, by controlling the first merging link 6, whether the first oil source P1 and the third oil source P3 supply oil to at least one of the first working link 101, the second working link 102 and the third working link 103 together can be controlled, thereby effectively meeting the demand of at least one of the first working link 101, the second working link 102 and the third working link 103 for different working speeds, and realizing a working process that is more in line with actual demand.

[0067] It can be seen that, by further setting the third working link 103, the third oil source P3 and the first merging link 6 on the basis of the first working link 101, the second working link 102, the first oil source P1 and the second oil source P2, not only the composite action stability of at least two of the first working link 101, the second working link 102 and the third working link 103 can be improved, but also the requirements of different first working links 101, second working links 102 and third working links 103 for different working speeds can be met, the working flexibility is improved, and the adaptability of the hydraulic system 100 to different working conditions is improved.

[0068] For another example, referring to Figure 2 In some embodiments, the working system 10 not only includes the first working link 101, the second working link 102 and the third working link 103, but also includes a fourth working link 104, and the oil supply system 20 further includes a fourth oil source P4. The fourth working link 104 is arranged in parallel with the third working link 103 and includes a reversing valve 2 and a pressure compensating valve 3. The inlet of the pressure compensating valve 3 of the fourth working link 104 is connected with the third oil source P3. The oil path between the pressure compensating valve 3 and the reversing valve 2 of the fourth working link 104 is connected with the fourth oil source P4. Moreover, the fourth oil source P4 and the third oil source P3 are connected with the first control end 31 and / or the second control end 32 of the pressure compensating valve 3 of the fourth working link 104 through the second oil supply control system 8. The second oil supply control system 8 leads the one with higher pressure between the third oil source P3 and the fourth oil source P4 to the first control end 31 and / or the second control end 32 of the pressure compensating valve 3 of the fourth working link 104, so as to control the pressure compensating valve 3 of the fourth working link 104 to switch to the first valve position or the second valve position.

[0069] Based on the above scheme, when at least two of the first working link 101, the second working link 102, the third working link 103 and the fourth working link 104 perform composite action, the second oil source P2 can supply oil to the first working link 101, the first oil source P1 can supply oil to the second working link 102, the third oil source P3 can supply oil to the third working link 103, and the fourth oil source P4 can supply oil to the fourth working link 104, so that the first working link 101, the second working link 102, the third working link 103 and the fourth working link 104 can be supplied by different oil sources, thereby even in the case of flow saturation, at least two of the first working link 101, the second working link 102, the third working link 103 and the fourth working link 104 can perform composite action to obtain the required flow, and synchronous action, thereby preventing the phenomenon that the system flow preferentially flows to the low-load actuator when sharing the same oil source, effectively solving the problem that the light and heavy load actuators of the hydraulic system using the pre-valve compensation mode cannot work synchronously in the case of flow saturation, and improving the stability of composite action.

[0070] Moreover, since the second oil supply control system 8 is arranged between the fourth working link 104 and the fourth oil source P4, whether the pressure compensation valve 3 of the fourth working link 104 switches to the first valve position or the second valve position can be controlled, and thus whether the third oil source P3 simultaneously supplies oil to the third working link 103 and the fourth working link 104, and / or whether the fourth oil source P4 supplies oil to the third working link 103 after merging with the third oil source P3 can be controlled, thereby meeting the requirements of the fourth working link 104 and / or the third working link 103 for different operating speeds.

[0071] As can be seen, by further arranging the fourth working link 104, the fourth oil source P4, and the second oil supply control system 8 on the basis of the first working link 101, the second working link 102, the third working link 103, the first oil source P1, the second oil source P2, and the third oil source P3, not only can the stability of the composite action of at least two of the first working link 101, the second working link 102, the third working link 103, and the fourth working link 104 be improved, but also the requirements of at least one of the first working link 101, the second working link 102, the third working link 103, and the fourth working link 104 for different operating speeds can be met, the operating flexibility can be improved, and the adaptability of the hydraulic system 100 to different working conditions can be improved.

[0072] For example, referring to FIG. 1, the first working link 101, the second working link 102, the third working link 103, and the fourth working link 104 are arranged in series, and the first oil source P1, the second oil source P2, and the third oil source P3 are arranged in series. Figure 3 In some embodiments, the working system 10 not only includes the first working link 101, the second working link 102, the third working link 103, and the fourth working link 104, but also includes a fifth working link 105, the fifth working link 105 is arranged in parallel with the fourth working link 104 and includes a reversing valve 2 and a pressure compensation valve 3, the third oil source P3 is connected to the inlet of the pressure compensation valve 3 of the fifth working link 105 and is connected to the inlets of the pressure compensation valves 3 of the fourth working link 104 and the third working link 103 through the second merging link 9, the second merging link 9 is arranged between the fourth working link 104 and the fifth working link 105 and controls whether the first oil source P1 communicates with the third oil source P3.

[0073] Based on the above scheme, when at least two of the first working link 101, the second working link 102, the third working link 103, the fourth working link 104, and the fifth working link 105 perform a composite action, different oil sources can be used to supply oil to the working links participating in the composite action, so that even in the case of flow saturation, at least two of the first working link 101, the second working link 102, the third working link 103, the fourth working link 104, and the fifth working link 105 can obtain the required flow when performing a composite action, thereby preventing the phenomenon that when the same oil source is shared, the system flow preferentially flows to the low-load actuator, effectively solving the problem that the light and heavy load actuators cannot work synchronously when the hydraulic system using the pre-valve compensation method is in flow saturation, and improving the stability of the composite action.

[0074] Moreover, since the second confluence connection 9 is arranged between the fourth working connection 104 and the fifth working connection 105, the second confluence connection 9 connects the first oil source P1 and the third oil source P3 and controls whether the first oil source P1 and the third oil source P3 confluence, therefore, by controlling the second confluence connection 9, it is also possible to control whether the first oil source P1 and the third oil source P3 supply oil together for at least one of the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104 and the fifth working connection 105, thereby effectively meeting the demand of at least one of the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104 and the fifth working connection 105 for different working speeds, and realizing a working process more in line with actual demand.

[0075] It can be seen that by further arranging the fifth working connection 105 and the second confluence connection 9 on the basis of the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104, the first oil source P1, the second oil source P2, the third oil source P3 and the fourth oil source P4, not only the stability of the composite action of at least two of the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104 and the fifth working connection 105 can be improved, but also the requirement of at least one of the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104 and the fifth working connection 105 for different working speeds can be met, the working flexibility is improved, and the adaptability of the hydraulic system 100 to different working conditions is improved.

[0076] Next, the present application will be further described in conjunction with the embodiment shown in Figures 1-3 .

[0077] First, the first embodiment shown in Figure 1 will be introduced.

[0078] As shown in Figure 1 , in the first embodiment, the hydraulic system 100 includes a working system 10 and an oil supply system 20, and the working system 10 is a load-sensitive multi-way valve system, which includes three working connections, i.e., the first working connection 101, the second working connection 102 and the third working connection 103, and a feedback device 7, and the oil supply system 20 includes a first oil source P1, a second oil source P2, a third oil source P3, a first one-way valve 4, a first oil supply control system 5 and a first confluence connection 6.

[0079] The first working link 101, the second working link 102 and the third working link 103 are arranged in parallel and have the same structure, and each includes a reversing control valve 1, a reversing valve 2 and a pressure compensation valve 3. The reversing control valve 1 is used to control the reversing of the reversing valve 2. The pressure compensation valve 3 is arranged in front of the reversing valve 2 and connected to the actuator of the engineering machinery through the reversing valve 2, so as to drive the actuator to act by supplying oil to the actuator. In the figure, A and B are used to represent the oil ports of the reversing valve 2 connected to the actuator. In order to distinguish different working links, different subscripts are used to represent different working links, for example, A and B of the first working link 101 are represented as A1 and B1, A and B of the second working link 102 are represented as A2 and B2, and A and B of the third working link 103 are represented as A3 and B3. In addition, Figure 1 T in the figure represents the oil return port of the hydraulic system 100. The corresponding oil return port T is connected to the reversing valve 2 of each working link.

[0080] Specifically, as shown in the figure, Figure 1 In this embodiment, the reversing valve 2 is a three-position five-way proportional reversing valve, which combines throttling and reversing functions and can realize throttling speed regulation. The reversing control valve 1 is an electro-hydraulic proportional control valve, which is connected to two reversing control ends of the reversing valve 2 to control the reversing of the reversing valve 2. The pressure compensation valve 3 is a two-position two-way hydraulic control valve, which has an inlet and an outlet and has a first control end 31 and a second control end 32. The first control end 31 is used to control the pressure compensation valve 3 to switch to the first valve position, so that the inlet and the outlet of the pressure compensation valve 3 are disconnected. The second control end 32 is used to control the pressure compensation valve 3 to switch to the second valve position, so that the inlet and the outlet of the pressure compensation valve 3 are connected. Figure 1 It can be seen that, in this embodiment, the first control end 31 of the pressure compensation valve 3 is connected to the outlet of the pressure compensation valve 3 (or the oil path between the pressure compensation valve 3 and the reversing valve 2), and the second control end 32 of the pressure compensation valve 3 is provided with a spring and connected to the oil path between the reversing valve 2 and the actuator.

[0081] The feedback device 7 is arranged between the oil path between the reversing valve 2 and the actuator of all working links and the load feedback oil port Ls of the hydraulic system 100, and is used to feedback the highest load pressure in all working links to the load feedback oil port Ls, so that the load sensitive control can be performed in cooperation with the variable pump of the hydraulic system 100. As shown in the figure, Figure 1 In this embodiment, the feedback device 7 includes a second one-way valve 71 corresponding to each working link. The inlet of each second one-way valve 71 is connected to the oil path between the reversing valve 2 and the actuator of the corresponding working link, and the outlets of all second one-way valves 71 are connected to the load sensitive feedback oil port Ls. Specifically, Figure 1It can be known that, in the embodiment, the feedback device 7 comprises three second check valves 71, which are in one-to-one correspondence with the first working joint 101, the second working joint 102 and the third working joint 103. The inlet of each second check valve 71 is connected with the oil path between the reversing valve 2 and the actuator of the corresponding working joint, and the outlets of all the second check valves 71 are connected with the load-sensitive feedback oil port Ls. In this way, the feedback device 7 can feed back the highest load pressure in all the working joints to the load feedback oil port Ls, so as to realize the load-sensitive control function.

[0082] The first oil source P1, the second oil source P2 and the third oil source P3 are used to supply oil to the first working joint 101, the second working joint 102 and the third working joint 103, and meet different oil supply requirements of the first working joint 101, the second working joint 102 and the third working joint 103 when performing single action, two actions and three actions under the control of the first oil supply control system 5 and the first merging joint 6.

[0083] As shown in Figure 1 In the embodiment, the first oil source P1 is connected with the inlet of the pressure compensation valve 3 of the first working joint 101, the second oil source P2 is connected with the oil path between the pressure compensation valve 3 and the reversing valve 2 of the first working joint 101 through the first check valve 4, the inlet of the first check valve 4 is connected with the oil path between the pressure compensation valve 3 and the reversing valve 2 of the first working joint 101, the outlet of the first check valve 4 is connected with the second oil source P2, so that the oil flows in one direction from the second oil source P2 to the reversing valve 2 of the first working joint 101, preventing backflow of the oil, the third oil source P3 is connected with the inlet of the pressure compensation valve 3 of the third working joint 103, the first oil source P1 and the third oil source P3 are connected through the first merging joint 6, the first oil source P1 and the second oil source P2 are connected through the first oil supply control system 5, and the first oil supply control system 5 is connected with the two control ends (i.e. the first control end 31 and the second control end 32) of the pressure compensation valve 3 of the first working joint 101.

[0084] Specifically, in this embodiment, the first oil supply control system 5 comprises a shuttle valve 54, a first regulating valve 51 and a second regulating valve 52. The shuttle valve 54 serves as a comparison device 53, two inlets of the shuttle valve 54 are connected with the first oil source P1 and the second oil source P2 respectively, and an outlet of the shuttle valve 54 is connected with the first regulating valve 51 and the second regulating valve 52. The first regulating valve 51 is an electrically controlled proportional pressure reducing valve, a first valve port of the first regulating valve 51 is connected with the outlet of the shuttle valve 54, a second valve port of the first regulating valve 51 is connected with a drain port L of the hydraulic system 100, a third valve port of the first regulating valve 51 is connected with the first control end 31 of the pressure compensating valve 3 of the first working link 101, and the third valve port of the first regulating valve 51 is in switching communication with the first valve port and the second valve port. The second regulating valve 52 is a two-position three-way electromagnetic valve, a first oil port of the second regulating valve 52 is connected with the outlet of the shuttle valve 54, a second oil port of the second regulating valve 52 is connected with an oil passage between the directional valve 2 of the first working link 101 and an actuator of the construction machine, a third oil port of the second regulating valve 52 is connected with the second control end 32 of the pressure compensating valve 3 of the first working link 101, and the third oil port of the second regulating valve 52 is in switching communication with the first oil port and the second oil port.

[0085] Based on the above arrangement, by controlling whether the first regulating valve 51 is energized or not, it can be controlled whether the first regulating valve 51 connects the shuttle valve 54 with the first control end 31 of the pressure compensating valve 3 of the first working link 101 or not, and further, it can be controlled whether the one with higher pressure between the first oil source P1 and the second oil source P2 obtained by the comparison of the shuttle valve 54 is led to the first control end 31 of the pressure compensating valve 3 of the first working link 101 or not, so as to realize the control of whether the pressure compensating valve 3 of the first working link 101 is switched to the first valve position or not, and thus the first oil supply control system 5 which is connected between the first oil source P1 and the second oil source P2 and the control end of the pressure compensating valve 3 of the first working link 101 can control whether the first oil source P1 supplies oil to the first working link 101 or not.

[0086] Further, by controlling whether the second regulating valve 52 is energized or not, it can be controlled whether the second regulating valve 52 connects the shuttle valve 54 with the second control end 32 of the pressure compensating valve 3 of the first working link 101 or not, and further, it can be controlled whether the one with higher pressure between the first oil source P1 and the second oil source P2 obtained by the comparison of the shuttle valve 54 is led to the second control end 32 of the pressure compensating valve 3 of the first working link 101 or not, so as to realize the control of whether the pressure compensating valve 3 of the first working link 101 is switched to the second valve position or not, and thus the first oil supply control system 5 which is connected between the first oil source P1 and the second oil source P2 and the control end of the pressure compensating valve 3 of the first working link 101 can control whether the second oil source P1 is merged with other oil sources (for example, the first oil source P1) via the pressure compensating valve 3 of the first working link 101 to supply oil to the second working link 102 or not. In this embodiment, the second regulating valve 52 and the first regulating valve 51 cannot be energized at the same time, that is, they are either both de-energized or one is de-energized while the other is energized.

[0087] In addition, as shown in FIG. 1, the first oil supply control system 5 further comprises a third regulating valve 53, a fourth regulating valve 54 and a fifth regulating valve 55. Figure 1As shown, in this embodiment, the first combination link 6 is arranged between the second working link 102 and the third working link 103, and includes a combination valve 61 and a combination control valve 62. The combination valve 61 connects the first oil source PI and the third oil source P3, and has a first working position and a second working position. When in the first working position, the combination valve 61 cuts off the first oil source PI and the third oil source P3, so that the first oil source PI and the third oil source P3 are independent of each other and do not combine, at this time, it is called that the first combination link 6 is in a closed state. When in the second working position, the combination valve 61 connects the first oil source PI and the third oil source P3, so that the first oil source PI and the third oil source P3 can combine, at this time, it is called that the first combination link 6 is in an open state. The combination control valve 62 is connected with the control end of the combination valve 61, and is used to control the combination valve 61 to switch between the first working position and the second working position, so as to control whether the combination valve 61 combines the first oil source PI and the third oil source P3. Specifically, in this embodiment, the combination control valve 62 is an electric control valve, so that only by controlling whether the combination control valve 62 is powered on, the combination of the first oil source PI and the third oil source P3 by the first combination link 6 can be controlled.

[0088] The hydraulic system 100 of this embodiment can realize several different working states, including standby state (i.e., the first working link 101, the second working link 102 and the third working link 103 do not start to act), single action state (i.e., only one of the first working link 101, the second working link 102 and the third working link 103 acts), two-action state (i.e., any two of the first working link 101, the second working link 102 and the third working link 103 compound act), and three-action state (i.e., the first working link 101, the second working link 102 and the third working link 103 all act). Next, the four different working states will be described respectively.

[0089] 1. Standby state

[0090] When in the standby state, the commutation control valves 1 of the first working link 101, the second working link 102 and the third working link 103 are all powered off, and the first control valve 51, the second control valve 52 and the combination control valve 62 are all powered off, so that the first oil source PI and the third oil source P3 do not combine, and are all in the standby oil supply state as the second oil source P2.

[0091] 2. Single action state

[0092] The single action state includes three different cases, i.e., the first working link single action state in which only the first working link 101 acts, the second working link single action state in which only the second working link 102 acts, and the third working link single action state in which only the third working link 103 acts.

[0093] 2.1. First working link single action state

[0094] When the first working link 101 is single-acting, the reversing control valves 1 of the second working link 102 and the third working link 103 are both de-energized, the reversing control valve 1 of the first working link 101 is energized, and the reversing valves 2 of the second working link 102 and the third working link 103 are both in the neutral position to drive the actuator to be inaction, while the reversing valve 2 of the first working link 101 is reversed from the neutral position to the left position or the right position to drive the actuator to act. In this case, the first oil source P1 and / or the second oil source P2 can be controlled to supply oil (only when slow speed is required, the first working link 101 can be supplied with oil by only one of the first oil source P1 and the second oil source P2, and when fast speed is required, the first working link 101 can be supplied with oil by the first oil source P1 and the second oil source P2 together, to improve the working speed of the first working link 101); or the confluence control valve 62 of the first confluence link 6 can be controlled to be energized to connect the third oil source P3 with the inlet of the pressure compensation valve 3 of the first working link 101, and the first working link 101 is supplied with oil by the third oil source P3, and according to different speed requirements, the third oil source P3 can be selected to supply oil together with at least one of the first oil source P1 and the second oil source P2.

[0095] In the case where the first oil source P1 supplies oil to the first working link 101, the first regulating valve 51 is de-energized to enable the first oil source P1 to communicate with the reversing valve 2 of the first working link 101 through the pressure compensation valve 3 of the first working link 101, and supply oil to the first working link 101.

[0096] In addition, in the case where the first oil source P1 does not supply oil to the first working link 101, the first oil source P1 can be directly not supplied with oil, or although the first oil source P1 is supplied with oil, the first regulating valve 51 is energized to cut off the oil path between the first oil source P1 and the reversing valve 2 of the first working link 101 by the pressure compensation valve 3 of the first working link 101, so that the pressure oil provided by the first oil source P1 cannot reach the reversing valve 2 of the first working link 101 through the pressure compensation valve 3 of the first working link 101.

[0097] 2.2, second working link single-acting state

[0098] When the second working link 102 is single-acting, the reversing control valves 1 of the first working link 101 and the third working link 103 are both de-energized, the reversing control valve 1 of the second working link 102 is energized, the reversing valves 2 of the first working link 101 and the third working link 103 are both in the neutral position and do not drive the actuator to act, and the reversing valve 2 of the second working link 102 is switched from the neutral position to the left position or the right position to drive the actuator to act. In this case, oil can be supplied by at least one of the first oil source P1, the second oil source P2 and the third oil source P3. When the third oil source P3 supplies oil, the confluence control valve 62 of the first confluence link 6 is energized. When the second oil source P2 supplies oil, the second regulating valve 52 is energized, so that the pressure oil supplied by the second oil source P2 can flow through the first check valve 4 in the reverse direction and then flow to the second working link 102 through the pressure compensation valve 3 of the first working link 101.

[0099] Specifically, when oil is supplied at the first oil source P1 and the second oil source P2, and the first regulating valve 51 is de-energized and the second regulating valve 52 is energized, the first oil source P1 and the second oil source P2 can confluence and supply oil to the single-acting second working link 102. When the first oil source P1 supplies oil to the second working link 102, if the second regulating valve 52 is de-energized, the oil of the first oil source P1 can flow through the pressure compensation valve 3 of the first working link 101 and act on the first control end 31 of the pressure compensation valve 3 of the first working link 101, so that the pressure compensation valve 3 of the first working link 101 is switched to the first valve position. In this case, even if the oil pump of the second oil source P2 is turned on, the second oil source P2 cannot flow through the pressure compensation valve 3 of the first working link 101 in the reverse direction and confluence with the first oil source P1. In this case, the second regulating valve 52 is energized to guide the higher pressure of the first oil source P1 and the second oil source P2 to the second control end 32 of the pressure compensation valve 3 of the first working link 101, so that the pressure compensation valve 3 of the first working link 101 is switched from the first valve position back to the second valve position, thereby effectively solving the corresponding problem and enabling the second oil source P2 to confluence with the first oil source P1.

[0100] In addition, when oil is supplied at the first oil source P1 and the third oil source P3, and the confluence control valve 62 of the first confluence link 6 is energized, the first oil source P1 and the second oil source P3 can confluence and supply oil to the single-acting second working link 102.

[0101] In addition, when oil is supplied at the first oil source P1 and the third oil source P3, and the confluence control valve 62 of the first confluence link 6 is energized, the first oil source P1 and the second oil source P3 can confluence and supply oil to the single-acting second working link 102.

[0102] When only one of the first oil source P1, the second oil source P2 and the third oil source P3 supplies oil to the second working link 102, the operation speed of the second working link 102 is slower, which can meet the lower operation speed requirement of the second working link 102; and when the second working link 102 needs faster operation speed, at least two of the first oil source P1, the second oil source P2 and the third oil source P3 can supply oil to the second working link 102 to improve the operation speed of the second working link 102.

[0103] 2.3, Third working link single action state

[0104] When the third working link 103 is in single action, the reversing control valves 1 of the first working link 101 and the second working link 102 are both not powered, the reversing control valve 1 of the third working link 103 is powered, the reversing valves 2 of the first working link 101 and the second working link 102 are both in the neutral position not driving the actuator to act, and the reversing valve 2 of the third working link 103 is reversed from the neutral position to the left position or the right position driving the actuator to act. In this case, the third oil source P3 can be controlled to supply oil, and if the required speed of the third working link 103 is large, the first oil source P1 and / or the second oil source P2 can be combined with the third oil source P3 to supply oil to the single-acting third working link 103. When the first oil source P1 is combined with the third oil source P3, the combination control valve 62 of the first combination link 6 is powered; and when the second oil source P2 is combined with the third oil source P3, the combination control valve 62 of the first combination link 6 is powered, and the second regulating valve 52 is powered.

[0105] It can be seen that in the single action state, each working link can be supplied with oil by one, two or three of the first oil source P1, the second oil source P2 and the third oil source P3 to complete low-speed, relatively high-speed and high-speed actions. Since each working link can be supplied with oil by different oil sources, the speed of single action can be improved, and the operation efficiency can be improved.

[0106] 3, Two action state

[0107] The two action state includes three different cases of the first working link 101 and the second working link 102 composite action, the first working link 101 and the third working link 103 composite action, and the second working link 102 and the third working link 103 composite action.

[0108] 3.1, First working link and second working link composite action

[0109] When the first working link 101 and the second working link 102 are in the composite action, the reversing control valve 1 of the third working link 103 is de-energized, and the reversing control valves 1 of the first working link 101 and the second working link 102 are energized. In this case, the first control valve 51 is energized to close the pressure compensation valve 3 of the first working link 101, so that the first working link 101 is only supplied with oil from the second oil source P2, and the first oil source P1 and / or the third oil source P3 are controlled to supply oil to the second working link 102; or, the pressure compensation valve 3 of the first working link 101 can not be closed, so that the first oil source P1 and / or the third oil source P3 supply oil to the first working link 101 at the same time of supplying oil to the second working link 102, so as to improve the working speed of the first working link 101.

[0110] 3.2, Composite action of the first working link and the third working link

[0111] When the first working link 101 and the third working link 103 are in the composite action, the reversing control valve 1 of the second working link 102 is de-energized, and the reversing control valves 1 of the first working link 101 and the third working link 103 are energized. In this case, the first combined link 6 is de-energized to be closed, so that the first oil source P1 and / or the second oil source P2 supply oil to the first working link 101, and the third oil source P3 supplies oil to the third working link 103; or, the first combined link 6 is energized to be opened, so that the first oil source P1 and / or the second oil source P2 which supply oil to the first working link 101 combine with the third oil source P3 to supply oil to the third working link 103, so as to improve the working speed of the third working link 103.

[0112] 3.3, Composite action of the second working link and the third working link

[0113] When the second working link 102 and the third working link 103 are in the composite action, the reversing control valve 1 of the first working link 101 is de-energized, and the reversing control valves 1 of the second working link 102 and the third working link 103 are energized. In this case, the first combined link 6 can be closed, so that the first oil source P1 (and / or the second oil source P2) and the third oil source P3 supply oil to the second working link 102 and the third working link 103 respectively, or the first combined link 6 is opened, and the first oil source P1 (and / or the second oil source P2) and the third oil source P3 supply oil to the second working link 102 and the third working link 103 together.

[0114] It can be seen that in the double-action state, the two working links in the composite action can be independently supplied with oil by different oil sources, or can be supplied with oil by different oil sources in combination. When the two working links in the composite action are independently supplied with oil by different oil sources, the two working links in the composite action do not interfere with each other, which can effectively prevent the occurrence of the problem of different steps in the composite action, and further improve the stability of the composite action.

[0115] 4, Triple action state

[0116] In the three-action state, the first working link 101, the second working link 102 and the third working link 103 perform a composite action, and the three reversing control valves 1 are powered on. In this case, the first combined link 6 is powered off, the second regulating valve 52 is powered off, and the first regulating valve 51 is powered on, which closes the pressure compensating valve 3 of the first working link 101, so that the first oil source P1 supplies oil to the second working link 102 alone, the second oil source P2 supplies oil to the first working link 101 alone, and the third oil source P3 supplies oil to the third working link 103 alone. In this way, the three working links are controlled by independent oil sources and do not interfere with each other, which can effectively improve the stability of the composite action.

[0117] It can be seen that the hydraulic system 100 of the embodiment can realize that different oil sources combine to supply oil to the same working link when the three working links perform single action, which improves the operation speed of single action. Moreover, when two or three working links perform composite action, the electric control is switched to the independent oil source control state, so that each execution element is supplied with oil by an independent oil source and does not interfere with each other, effectively solving the problem that the light and heavy load execution mechanisms cannot work synchronously when the flow is saturated, and improving the stability of the composite action.

[0118] Next, the second embodiment shown in Figure 2 will be introduced. For simplicity of description, only the differences between the second embodiment and the first embodiment shown in Figure 1 will be described in the following, and the other parts not described can be understood with reference to the description of the first embodiment.

[0119] As Figure 2 shown in the second embodiment, the hydraulic system 100 not only includes the first working link 101, the second working link 102, the third working link 103, the first oil source P1, the second oil source P2, the third oil source P3, the first oil supply control system 5 and the first combined link 6 in the first embodiment, but also includes the fourth working link 104, the fourth oil source P4 and the second oil supply control system 8. That is to say, the second embodiment further increases the fourth working link 104, the fourth oil source P4 and the second oil supply control system 8 on the basis of the first embodiment. Among them, the first working link 101, the second working link 102, the third working link 103, the first oil source P1, the second oil source P2, the third oil source P3, the first oil supply control system 5 and the first combined link 6 are arranged in the same way as in the first embodiment, and will not be described again. Therefore, the setting features of the fourth working link 104, the fourth oil source P4 and the second oil supply control system 8 will be mainly introduced in the following.

[0120] By Figure 2It can be seen that in the second embodiment, the fourth working link 104 is arranged in parallel with the third working link 103 and includes the reversing valve 2 and the pressure compensation valve 3. The inlet of the pressure compensation valve 3 of the fourth working link 104 is connected with the third oil source P3. The fourth oil source P4 is connected with the oil passage between the pressure compensation valve 3 and the reversing valve 2 of the fourth working link 104 through the first one-way valve 4. Moreover, the fourth working link 104 is connected with the fourth oil source P4 through the second oil supply control system 8, which is used to lead the one with higher pressure between the third oil source P3 and the fourth oil source P4 to the first control end 31 and the second control end 32 of the pressure compensation valve 3 of the fourth working link 104, so as to control the pressure compensation valve 3 of the fourth working link 104 to switch to the first valve position or the second valve position.

[0121] In the second oil supply control system 8, the two inlets of the shuttle valve 54 are no longer connected with the first oil source P1 and the second oil source P2 respectively, but are connected with the third oil source P3 and the fourth oil source P4, and the first regulating valve 51 and the second regulating valve 52 are no longer connected with the first control end 31 and the second control end 32 of the pressure compensation valve 3 of the first working link 101 respectively, but are connected with the first control end 31 and the second control end 32 of the pressure compensation valve 3 of the fourth working link 104, so that the second oil supply control system 8 is not used to lead the one with higher pressure between the first oil source P1 and the second oil source P2 to the first control end 31 and the second control end 32 of the pressure compensation valve 3 of the first working link 101, but is used to lead the one with higher pressure between the third oil source P3 and the fourth oil source P4 to the first control end 31 and the second control end 32 of the pressure compensation valve 3 of the fourth working link 104, so as to control the pressure compensation valve 3 of the fourth working link 104 to switch between the first valve position and the second valve position, so that the second oil supply control system 8 can control whether the third oil source P3 supplies oil to the fourth working link 104 and whether the fourth oil source P4 supplies oil to the third working link 103 after reversely flowing through the pressure compensation valve 3 of the fourth working link 104.

[0122] Based on the above arrangement, in the second embodiment, the hydraulic system 100 can realize that different oil sources are combined to supply oil to the same working link when four working links are single-acted, so as to improve the working speed of single-acting, and can be electrically controlled to switch to the independent oil source control state when two, three or four working links are compound-acted, so that each oil passage is supplied with oil by an independent oil source and does not interfere with each other, effectively solving the problem that the light and heavy load execution mechanisms cannot work synchronously when the flow is saturated, and improving the stability of compound action.

[0123] Next, the second embodiment will be described in detail. Figure 3The third embodiment is shown. For simplicity of description, only the differences between the second embodiment and Figure 1 the first embodiment and Figure 2 the second embodiment are described below. Other aspects not described can be understood with reference to the foregoing description of the first embodiment and the second embodiment.

[0124] As Figure 3 shown in the third embodiment, the hydraulic system 100 not only includes the first working connection 101, the second working connection 102, the third working connection 103, the fourth working connection 104, the first oil source P1, the second oil source P2, the third oil source P3, the fourth oil source P4, the first oil supply control system 5, the second oil supply control system 8, and the first combined connection 6, but also includes a fifth working connection 105 and a second combined connection 9, that is, the third embodiment is based on the second embodiment, further adding the fifth working connection 105 and the second combined connection 9.

[0125] Among them, the fifth working connection 105 is connected in parallel with the fourth working connection 104 and includes a reversing valve 2 and a pressure compensation valve 3. The inlet of the pressure compensation valve 3 of the fifth working connection 105 is connected with the third oil source P3. The second combined connection 9 is arranged between the fourth working connection 104 and the fifth working connection 105, and connects the third oil source P3 with the inlets of the pressure compensation valves 3 of the fourth working connection 104 and the third working connection 103. Moreover, the second combined connection 9 and the first combined connection 6 are both combined connections, which, like the first combined connection 6, also include a combined valve 61 and a combined control valve 62. The combined control valve 62 controls whether the first oil source P1 and the third oil source P3 are combined to supply oil by controlling the combined valve 61 to switch between the first working position and the second working position.

[0126] Based on the above arrangement, in the third embodiment, the hydraulic system 100 can realize that different oil sources are combined to supply oil to the same working connection during single action of five working connections, thereby improving the working speed of single action, and can be switched to an independent oil source control state during composite action of two, three, four or five working connections, so that each execution element is supplied by an independent oil source and does not interfere with each other, effectively solving the problem that light and heavy load execution mechanisms cannot work synchronously when the flow is saturated, and improving the stability of composite action.

[0127] It can be seen that the hydraulic system 100 provided by the present application can realize that different oil sources are combined to supply oil to the same working connection during single action of different working connections, thereby improving the working speed of single action, and can be switched to an independent oil source control state during composite action of different working connections, so that each execution element is supplied by an independent oil source and does not interfere with each other, effectively solving the problem that light and heavy load execution mechanisms cannot work synchronously when the flow is saturated, and improving the stability of composite action.

[0128] Moreover, the hydraulic system 100 provided by the present application still adopts the pre-valve compensation mode, i.e., the pressure compensation valve 3 is arranged in front of the reversing valve 2. In this way, compared with other solutions in which the pressure compensation valve 3 is arranged behind the reversing valve 2, the structure of the working system 10 is less changed, and cost is saved.

[0129] Based on the hydraulic system 100 of the foregoing embodiments, the present application further provides an engineering machine comprising the hydraulic system 100 of any of the embodiments of the present application. As an example, the engineering machine is an engineering vehicle such as a crane.

[0130] The above description is merely exemplary embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hydraulic system (100), characterized in that, The working system (10) comprises a first working link (101) and a second working link (102), the first working link (101) and the second working link (102) are arranged in parallel, and each comprises a reversing valve (2) and a pressure compensation valve (3), an outlet of the pressure compensation valve (3) is connected with an actuator of the engineering machinery through the reversing valve (2) to drive the actuator to act, the pressure compensation valve (3) has a first control end (31) and a second control end (32), the first control end (31) and the second control end (32) control the pressure compensation valve (3) to switch to a first valve position and a second valve position respectively, when being in the first valve position, an inlet and an outlet of the pressure compensation valve (3) are disconnected, when being in the second valve position, the inlet and the outlet of the pressure compensation valve (3) are communicated; and The oil supply system (20) comprises a first oil source (P1), a second oil source (P2) and a first oil supply control system (5), the first oil source (P1) is connected with inlets of the pressure compensation valves (3) of the first working link (101) and the second working link (102), the second oil source (P2) is connected with an oil path between the reversing valve (2) and the pressure compensation valve (3) of the first working link (101), and the first oil supply control system (5) is used for leading one with higher pressure between the first oil source (P1) and the second oil source (P2) to the first control end (31) and / or the second control end (32) of the pressure compensation valve (3) of the first working link (101) to control the pressure compensation valve (3) of the first working link (101) to switch to the first valve position or the second valve position. The first oil supply control system (5) comprises a comparison device (53), the comparison device (53) is connected with the first oil source (P1) and the second oil source (P2), and the first oil supply control system (5) further comprises at least one of the following:

2. The hydraulic system (100) of claim 1, characterized in that A first regulating valve (51) is connected between the comparison device (53) and the first control end (31) of the pressure compensation valve (3) of the first working link (101) and controls whether the comparison device (53) and the first control end (31) of the pressure compensation valve (3) of the first working link (101) are communicated, so as to control whether the one with higher pressure between the first oil source (P1) and the second oil source (P2) compared by the comparison device (53) is led to the first control end (31) of the pressure compensation valve (3) of the first working link (101); ​ A second regulating valve (52) is connected to the second control end (32) of the pressure compensator valve (3) of the first working connection (101) and controls whether the second control end (32) of the pressure compensator valve (3) of the first working connection (101) is communicated with the comparison device (53) or not, so as to control whether the one with higher pressure between the first oil source (P1) and the second oil source (P2) compared by the comparison device (53) is led to the second control end (32) of the pressure compensator valve (3) of the first working connection (101) or not.

3. The hydraulic system (100) of claim 2, characterized in that The comparison device (53) comprises a shuttle valve (54), two inlets of the shuttle valve (54) are connected to the first oil source (P1) and the second oil source (P2) respectively, and an outlet of the shuttle valve (54) is connected to the first regulating valve (51) and / or the second regulating valve (52).

4. The hydraulic system (100) according to claim 2, characterized in that, The first regulating valve (51) comprises a first valve port, a second valve port and a third valve port, the first valve port is connected to the comparison device (53), the second valve port is connected to the oil drain port (L) of the hydraulic system (100), the third valve port is connected to the first control end (31) of the pressure compensator valve (3) of the first working connection (101) and is communicated with the first valve port and the second valve port in a switching manner, so as to control whether the first control end (31) of the pressure compensator valve (3) of the first working connection (101) is communicated with the comparison device (53) or not; and / or, The second regulating valve (52) comprises a first oil port, a second oil port and a third oil port, the first oil port is connected to the comparison device (53), the second oil port is connected to an oil path between the directional valve (2) of the first working connection (101) and an actuator of the engineering machinery, and the third oil port is connected to the second control end (32) of the pressure compensator valve (3) of the first working connection (101) and is communicated with the first oil port and the second oil port in a switching manner, so as to control whether the second control end (32) of the pressure compensator valve (3) of the first working connection (101) is communicated with the comparison device (53) or not.

5. The hydraulic system (100) of claim 2, characterized in that, The first regulating valve (51) and / or the second regulating valve (52) is an electric control valve.

6. The hydraulic system (100) of claim 2, characterized in that, The first regulating valve (51) is a proportional pressure reducing valve.

7. The hydraulic system (100) according to any one of claims 1-6, characterized in that, The oil path between the second oil source (P2) and the directional valve (2) and the pressure compensator valve (3) of the first working connection (101) is connected through a first one-way valve (4), so that the oil flows in a one-way direction from the second oil source (P2) to the directional valve (2) of the first working connection (101).

8. The hydraulic system (100) according to any one of claims 1-6, characterized in that, The working system (10) further comprises a third working link (103) which is arranged in parallel with the first working link (101) and the second working link (102) and comprises the reversing valve (2) and the pressure compensation valve (3), and the oil supply system (20) further comprises a third oil source (P3) connected with the inlet of the pressure compensation valve (3) of the third working link (103) and a first merging link (6) arranged between the second working link (102) and the third working link (103) and connecting the first oil source (P1) and the third oil source (P3) to control whether the first oil source (P1) and the third oil source (P3) are merged.

9. The hydraulic system (100) of claim 8, characterized in that, The working system (10) further comprises a fourth working link (104) which is arranged in parallel with the third working link (103) and comprises the reversing valve (2) and the pressure compensation valve (3), the inlet of the pressure compensation valve (3) of the fourth working link (104) is connected with the third oil source (P3), the oil path between the pressure compensation valve (3) and the reversing valve (2) of the fourth working link (104) is connected with the fourth oil source (P4), and the fourth oil source (P4) and the third oil source (P3) are connected with the first control end (31) and / or the second control end (32) of the pressure compensation valve (3) of the fourth working link (104) through a second oil supply control system (8), the second oil supply control system (8) is used to guide the one with higher pressure between the third oil source (P3) and the fourth oil source (P4) to the first control end (31) and / or the second control end (32) of the pressure compensation valve (3) of the fourth working link (104) to control the pressure compensation valve (3) of the fourth working link (104) to switch to the first valve position or the second valve position.

10. The hydraulic system (100) of claim 9, characterized in that The working system (10) further comprises a fifth working link (105) which is arranged in parallel with the fourth working link (104) and comprises the reversing valve (2) and the pressure compensation valve (3), the third oil source (P3) is connected with the inlet of the pressure compensation valve (3) of the fifth working link (105) and connected with the inlets of the pressure compensation valves (3) of the fourth working link (104) and the third working link (103) through a second merging link (9), the second merging link (9) is arranged between the fourth working link (104) and the fifth working link (105) and controls whether the first oil source (P1) and the third oil source (P3) are communicated.

11. A working machine, characterized in that The hydraulic system (100) comprises the hydraulic system (100) according to any one of claims 1-10.

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