An engineering machine and hydraulic control system

Abstract

The application discloses an engineering machine and a hydraulic control system, and relates to the technical field of hydraulic control, and the hydraulic control system is used for controlling the work of a first executing element and a second executing element, and comprises a variable pump, a negative flow control multi-way valve connected with the first executing element, an adjusting oil path connected with the negative flow control multi-way valve and the variable pump, a load-sensitive control multi-way valve connected with the second executing element and the variable pump, and a priority valve. The priority valve is provided with a hydraulic oil input port connected with an output oil port of the variable pump, a hydraulic oil output port connected with an input oil port of the negative flow control multi-way valve, and a pressure interface connected with a load-sensitive feedback port of the load-sensitive control multi-way valve. The hydraulic control system solves the technical problem of cost increase caused by the increase of the load-sensitive pump due to the difficulty of the negative flow control system in meeting the work requirement of the equipment, and realizes the technical effect of single-pump oil supply to the negative flow control system and the load-sensitive control system, thereby reducing the cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic control, in particular to an engineering machine and a hydraulic control system. BACKGROUND

[0002] At present, in the industry of large mobile engineering machines (such as excavators), widely used hydraulic control systems include load-sensitive control systems, negative flow control systems, positive flow control systems, etc.

[0003] The negative flow control system in the prior art has excellent performance such as strong oil passing ability, fast response speed, and good energy saving effect, and is usually adopted by large mobile machines. However, the negative flow control system also has its shortcomings when the large mobile machines are doing posture adjustment actions. At this time, it is often necessary to increase a load-sensitive pump to meet the demand of posture adjustment, which will lead to an increase in the cost of the equipment, and will also increase the difficulty of arrangement. In addition, the load-sensitive pump has a small working proportion, and when other systems are working, the pump is usually in standby state and has a certain hydraulic oil output, which leads to energy waste and also increases the cost.

[0004] Therefore, how to avoid the increase in cost caused by the increase in the load-sensitive pump due to the difficulty of the negative flow control system in meeting the working needs of the equipment is a technical problem that needs to be solved by those skilled in the art at present. SUMMARY

[0005] The purpose of the present application is to provide an engineering machine and a hydraulic control system, which solve the technical problem of cost increase caused by the increase in the load-sensitive pump due to the difficulty of the traditional negative flow control system in meeting the working needs of the equipment.

[0006] To achieve the above-mentioned purpose, the present application provides a hydraulic control system for controlling the work of a first actuator and a second actuator, comprising:

[0007] a variable pump for realizing variable flow output of hydraulic oil;

[0008] a negative flow control multi-way valve connected with the first actuator;

[0009] an adjusting oil circuit connected with the negative flow control multi-way valve and the variable pump, for feeding back pressure to the variable pump to adjust the hydraulic oil output of the variable pump;

[0010] a load-sensitive control multi-way valve connected with the second actuator and the variable pump, the load-sensitive control multi-way valve being provided with a load-sensitive feedback port;

[0011] The priority valve is provided with a hydraulic oil input port, a hydraulic oil output port and a pressure interface, the hydraulic oil input port is connected with an output oil port of the variable pump, the hydraulic oil output port is connected with an input oil port of the negative flow control multi-way valve, and the pressure interface is connected with a load-sensitive feedback port;

[0012] When the first and second actuating elements are not working, and the pressure of the hydraulic oil input port is greater than the valve core opening pressure of the priority valve, the hydraulic oil pushes the valve core of the priority valve from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve and the adjusting oil path, thereby reducing the hydraulic oil output of the variable pump;

[0013] When the second actuating element is working and the first actuating element is not working, and the pressure of the hydraulic oil input port is greater than the sum of the valve core opening pressure of the priority valve and the pressure of the pressure interface, the hydraulic oil pushes the valve core of the priority valve from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve and the adjusting oil path, thereby adjusting the hydraulic oil output of the variable pump to a state required by the working of the second actuating element;

[0014] When the first actuating element is working and the second actuating element is not working, and the pressure of the hydraulic oil input port is greater than the valve core opening pressure of the priority valve, the hydraulic oil pushes the valve core of the priority valve from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve and the first actuating element, and the hydraulic oil does not flow through the adjusting oil path, thereby increasing the hydraulic oil output of the variable pump.

[0015] Preferably, the adjusting oil path is provided with an adjusting valve assembly, the adjusting valve assembly is used for adjusting the hydraulic oil output of the variable pump, and the adjusting valve assembly comprises:

[0016] A bypass valve connected with the output oil port of the negative flow control multi-way valve;

[0017] A throttle valve connected with the bypass valve and used for controlling the hydraulic oil flow of the adjusting oil path.

[0018] Preferably, the adjusting valve assembly further comprises an overflow valve, and the overflow valve is connected with the throttle valve in parallel.

[0019] Preferably, a pressure control valve is further included, the pressure control valve is connected with an oil path between the pressure interface and the load-sensitive feedback port, when the pressure of a load-sensitive control system in which the load-sensitive control multi-way valve is located reaches a set pressure of the pressure control valve, the pressure control valve is opened, and the opening state of the priority valve is adjusted, so that the hydraulic oil flows through the negative flow control multi-way valve and the adjusting oil path, thereby reducing the displacement of the variable pump to a preset low value.

[0020] Preferably, a hydraulic oil tank is further included, and the adjusting oil path, the variable pump and the pressure control valve are all connected to the hydraulic oil tank.

[0021] Preferably, the pressure control valve is a proportional valve or an on-off valve, and a valve core of the pressure control valve is adjusted by electric control, hydraulic control or a spring.

[0022] Preferably, the priority valve is a proportional valve or an on-off valve, and a valve core of the priority valve is adjusted by electric control, hydraulic control or a spring.

[0023] Preferably, the priority valve is a two-position two-way valve.

[0024] Preferably, the negative flow control multi-way valve is a three-position eight-way valve.

[0025] The application provides an engineering machine comprising the hydraulic control system.

[0026] With respect to the background art, the hydraulic control system provided by the application is used for controlling the first actuator and the second actuator, and comprises a variable pump, a negative flow control multi-way valve, an adjusting oil path, a load-sensitive control multi-way valve and a priority valve.

[0027] In one aspect, the hydraulic control system provided by the application is provided with the priority valve, so that the negative flow control system in which the negative flow control multi-way valve is located and the load-sensitive control system in which the load-sensitive control multi-way valve is located are connected in parallel.

[0028] In another aspect, when the system is in standby state (at this time, the first and second actuators are not working): after the engine of the variable pump is started, the variable pump provides hydraulic oil, at this time, the load-sensitive feedback port on the load-sensitive control multi-way valve feeds zero pressure to the pressure interface on the priority valve, when the pressure of the hydraulic oil input port on the priority valve is greater than the valve core opening pressure of the priority valve, the hydraulic oil pushes away the valve core of the priority valve, and the valve core of the priority valve is pushed from the first working position to the second working position, the priority valve is opened, the hydraulic oil output by the variable pump flows through the negative flow control multi-way valve and the adjusting oil way, the adjusting oil way generates a certain pressure and feeds back to the control port of the variable pump, so as to reduce the hydraulic oil output of the variable pump, so that the variable pump is in a low displacement state, thereby reducing the energy loss of the hydraulic control system, at the same time, the hydraulic oil does not flow through the load-sensitive control multi-way valve, avoiding the increase of the energy loss of the hydraulic oil in the load-sensitive control system in which the load-sensitive control multi-way valve is located. In the working state of the system: when the load-sensitive control multi-way valve is opened, the second actuator starts to act, the load-sensitive feedback port on the load-sensitive control multi-way valve feeds pressure to the pressure interface on the priority valve, when the pressure of the hydraulic oil input port on the priority valve is greater than the valve core opening pressure of the priority valve + the feedback pressure of the pressure interface, the hydraulic oil pushes away the valve core of the priority valve, and the valve core of the priority valve is pushed from the first working position to the second working position, the priority valve is opened, the excess hydraulic oil flows through the negative flow control multi-way valve and the adjusting oil way, the adjusting oil way generates a corresponding pressure to adjust the hydraulic oil output of the variable pump, so that the hydraulic oil output of the variable pump is in the state required by the load-sensitive control system; when the system receives the actuation instruction of the first actuator, the negative flow control multi-way valve is opened, the hydraulic oil provided by the variable pump flows into the priority valve, when the pressure of the hydraulic oil input port on the priority valve is greater than the valve core opening pressure of the priority valve, the hydraulic oil pushes away the valve core of the priority valve, and the valve core of the priority valve is pushed from the first working position to the second working position, the priority valve is opened, the hydraulic oil flows from the priority valve to the negative flow control multi-way valve and the first actuator, the first actuator starts to act, and the hydraulic oil does not flow through the adjusting oil way, the pressure of the adjusting oil way is zero, so as to increase the hydraulic oil output of the variable pump, thereby making the variable pump output hydraulic oil at the maximum displacement.

[0029] In summary, the hydraulic control system provided by the application connects the negative flow control system in which the negative flow control valve is located and the load-sensitive control system in which the load-sensitive control valve is located in parallel, and realizes oil supply of the single pump to the negative flow control system and the load-sensitive control system, thereby reducing the use of one pump, improving the use efficiency of the pump, reducing the arrangement difficulty of the equipment, and reducing the equipment cost; at the same time, the energy loss of hydraulic oil in the load-sensitive control system in which the load-sensitive control valve is located is avoided in the standby state of the system, and the system pressure is regulated in the working state of the system, thereby reducing the energy loss of the hydraulic control system, improving the energy utilization rate and the working efficiency, and reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on the provided drawings.

[0031] Figure 1 The schematic diagram of the hydraulic control system provided by the embodiments of the present application.

[0032] Among them:

[0033] 1. variable pump, 2. hydraulic oil tank, 3. priority valve, 4. pressure control valve, 5. negative flow control valve, 6. first actuator, 7. regulating oil circuit, 8. bypass valve, 9. overflow valve, 10. throttle valve, 11. load-sensitive control valve, 12. second actuator. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0035] In order to make those skilled in the art better understand the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0036] Please refer to Figure 1The hydraulic control system is used for controlling the first actuating element 6 and the second actuating element 12 to work.

[0037] Of course, according to actual needs, the first actuating element 6 can be a hydraulic motor, and the second actuating element 12 can be a hydraulic cylinder. The hydraulic motor and the hydraulic cylinder respectively drive corresponding working mechanisms (such as various working mechanisms of an excavator) to work.

[0038] In the embodiment, the hydraulic control system comprises a variable pump 1, a negative flow control multi-way valve 5, an adjusting oil path 7, a load-sensitive control multi-way valve 11 and a priority valve 3.

[0039] The variable pump 1 (also referred to as a negative flow control variable pump) is used for realizing variable flow output of hydraulic oil. The variable pump 1 is a hydraulic element capable of automatically changing the flow of hydraulic oil according to operation needs, and mainly functions to automatically adjust the flow and pressure of hydraulic oil by changing the displacement of a working pump or an electric pump. The variable pump 1 is usually composed of a variable structure (such as a swash plate) and an adjusting mechanism (such as a hydraulic proportional valve), and can be divided into two types of direct control type and controlled type.

[0040] The negative flow control multi-way valve 5 is connected with the first actuating element 6, and is used for controlling the first actuating element 6 to work. The adjusting oil path 7 is connected with the negative flow control multi-way valve 5 and the variable pump 1, and is used for feeding back pressure to the variable pump 1 to adjust the output amount of hydraulic oil of the variable pump 1. The load-sensitive control multi-way valve 11 is connected with the second actuating element 12 and the variable pump 1, and is used for controlling the second actuating element 12 to work. Further, the load-sensitive control multi-way valve 11 is provided with a load-sensitive feedback port LS.

[0041] Correspondingly, the priority valve 3 is provided with a hydraulic oil input port P1, a hydraulic oil output port A and a pressure interface LS. The hydraulic oil input port P1 is connected with an output oil port of the variable pump 1. The hydraulic oil output port A is connected with an input oil port of the negative flow control multi-way valve 5. The pressure interface LS is connected with the load-sensitive feedback port LS. In this way, when the priority valve 3 is opened, the hydraulic oil output by the variable pump 1 flows through the negative flow control multi-way valve 5 and the adjusting oil path 7 to realize adjustment of the output amount of hydraulic oil of the variable pump 1.

[0042] In one aspect, the hydraulic control system provided by the application is provided with a priority valve 3, so that the negative flow control system in which the negative flow control multi-way valve 5 is located and the load-sensitive control system in which the load-sensitive control multi-way valve 11 is located are connected in parallel. Compared with the prior art in which two pumps are respectively arranged for two independent systems of the negative flow control system and the load-sensitive control system, the hydraulic control system of the application realizes oil supply of a single pump to the negative flow control system and the load-sensitive control system, reduces the use of one pump, and thus reduces the cost.

[0043] On the other hand, when the system is in standby state (at this time, the first actuating element and the second actuating element are not working): after the engine of the variable pump 1 is started, the variable pump 1 provides hydraulic oil, at this time, the load pressure is zero (the first actuating element 6 and the second actuating element 12 are not working), the pressure of the load sensitive feedback port LS on the load sensitive control multi-way valve 11 fed to the pressure interface LS on the priority valve 3 is zero, when the pressure of the hydraulic oil input port P1 on the priority valve 3 is greater than the valve core opening pressure of the priority valve 3, the hydraulic oil pushes away the valve core of the priority valve 3, and the valve core of the priority valve 3 is pushed from the first working position to the second working position, the priority valve 3 is opened, the hydraulic oil output by the variable pump 1 flows through the negative flow control multi-way valve 5 and the adjusting oil way 7, the adjusting oil way 7 generates a certain pressure and feeds back to the control port of the variable pump 1, so as to reduce the hydraulic oil output of the variable pump 1, so that the variable pump 1 is in low displacement state, thereby reducing the energy loss of the hydraulic control system, at the same time, the hydraulic oil does not flow through the load sensitive control multi-way valve 11, so as to avoid increasing the energy loss of the hydraulic oil in the load sensitive control system where the load sensitive control multi-way valve 11 is located when the system is in standby state. When the system is in working state: when the load sensitive control multi-way valve 11 is opened, the second actuating element 12 starts to act, the pressure of the load sensitive feedback port LS on the load sensitive control multi-way valve 11 fed to the pressure interface LS on the priority valve 3 is not zero, when the pressure of the hydraulic oil input port P1 on the priority valve 3 is greater than the valve core opening pressure of the priority valve 3 + the feedback pressure of the pressure interface LS, the hydraulic oil pushes away the valve core of the priority valve 3, and the valve core of the priority valve 3 is pushed from the first working position to the second working position, the priority valve 3 is opened, the excessive hydraulic oil flows through the negative flow control multi-way valve 5 and the adjusting oil way 7, the adjusting oil way 7 generates a corresponding pressure to adjust the hydraulic oil output of the variable pump 1, so that the hydraulic oil output of the variable pump 1 is in the state required by the load sensitive control system; when the system receives the actuating instruction of the first actuating element 6, the negative flow control multi-way valve 5 is opened, the hydraulic oil provided by the variable pump 1 flows into the priority valve 3, when the pressure of the hydraulic oil input port P1 on the priority valve 3 is greater than the valve core opening pressure of the priority valve 3, the hydraulic oil pushes away the valve core of the priority valve 3, and the valve core of the priority valve 3 is pushed from the first working position to the second working position, the priority valve 3 is opened, the hydraulic oil flows from the priority valve 3 to the negative flow control multi-way valve 5 and the first actuating element 6, the first actuating element 6 starts to act, and the hydraulic oil does not flow through the adjusting oil way 7, the pressure of the adjusting oil way 7 is zero, so as to increase the hydraulic oil output of the variable pump 1, thereby making the variable pump 1 output hydraulic oil at maximum displacement.

[0044] To sum up, the hydraulic control system provided by the application connects the negative flow control system in which the negative flow control valve 5 is located and the load-sensitive control system in which the load-sensitive control valve 11 is located in parallel, and realizes oil supply of the single pump to the negative flow control system and the load-sensitive control system, thereby reducing the use of one pump, improving the use efficiency of the pump, reducing the arrangement difficulty of the equipment, and reducing the equipment cost; at the same time, the energy loss of the hydraulic oil in the load-sensitive control system in which the load-sensitive control valve 11 is located is avoided in the standby state of the system, and the system pressure is regulated in the working state of the system, thereby reducing the energy loss of the hydraulic control system, improving the energy utilization rate and the working efficiency, and reducing the cost.

[0045] In some embodiments, the priority valve 3 is a two-position two-way valve.

[0046] It should be noted that the first working position of the valve core refers to the left position of the priority valve 3 as shown in FIG. 4, at this time, the priority valve 3 is in a closed state, and the second working position of the valve core refers to the right position of the priority valve 3 as shown in FIG. 5, at this time, the priority valve 3 is in an open state. Figure 1 Figure 1

[0047] Specifically, when the priority valve 3 is in a closed state, the load-sensitive control system in which the load-sensitive control valve 11 is located works, and the negative flow control system in which the negative flow control valve 5 is located does not work; when the priority valve 3 is in an open state, at this time, the hydraulic oil flows through the priority valve 3 and the negative flow control valve 5, the negative flow control system in which the negative flow control valve 5 is located works, and the load-sensitive control system in which the load-sensitive control valve 11 is located does not work. In this way, the conversion between the load-sensitive control system and the negative flow control system can be realized.

[0048] In some embodiments, the negative flow control valve 5 is a three-position eight-way valve.

[0049] Specifically, when the negative flow control valve 5 is in a center position as shown in FIG. 6, the input oil port of the negative flow control valve 5 is connected with the output oil port of the priority valve 3, the output oil port of the negative flow control valve 5 is connected with the adjusting oil path 7, and the input oil port of the negative flow control valve 5 is communicated with the output oil port of the negative flow control valve 5, at this time, the hydraulic oil can flow to the adjusting oil path 7 through the priority valve 3 and the negative flow control valve 5; when the negative flow control valve 5 is in a left position or a right position as shown in FIG. 7 or FIG. 8, the negative flow control valve 5 is communicated with the first actuating element 6, at this time, after the negative flow control valve 5 is opened, the hydraulic oil can flow to the first actuating element 6 through the priority valve 3 and the negative flow control valve 5, so that the first actuating element 6 is in a working state. Figure 1 Figure 1 ​​​​

[0050] In some embodiments, the adjusting valve assembly is arranged on the adjusting oil line 7, and is configured to adjust the hydraulic oil displacement of the variable pump 1.

[0051] In the present embodiment, the adjusting valve assembly comprises a bypass valve 8 and a throttle valve 10, the bypass valve 8 is connected to the output port of the negative flow control multi-way valve 5, and the throttle valve 10 is connected to the bypass valve 8 and is configured to control the hydraulic oil flow of the adjusting oil line 7.

[0052] In some embodiments, the bypass valve 8 is a two-position two-way valve. Specifically, when the bypass valve 8 is in the left position, the bypass valve 8 is in the open state, and when the bypass valve 8 is in the right position, the bypass valve 8 is in the closed state.

[0053] In some embodiments, the adjusting valve assembly further comprises an overflow valve 9, which is connected in parallel to the throttle valve 10, and is configured to control the hydraulic oil flow of the adjusting oil line 7.

[0054] In some embodiments, the hydraulic control system further comprises a pressure control valve 4, which is connected to the oil line between the pressure interface LS on the priority valve 3 and the load sensing feedback port LS on the load sensing control valve, and is configured to open when the pressure of the load sensing control system in which the load sensing control multi-way valve 11 is arranged reaches the set pressure of the pressure control valve 4, and to adjust the opening state of the priority valve 3 so that the hydraulic oil flows through the negative flow control multi-way valve 5 and the adjusting oil line 7 to reduce the displacement of the variable pump 1 to a preset low value.

[0055] It can be understood that, since the pressure control valve 4 is connected to the oil line between the pressure interface LS on the priority valve 3 and the load sensing feedback port LS on the load sensing control valve, when the pressure control valve 4 is opened, the pressure fed back from the load sensing feedback port LS on the load sensing control multi-way valve 11 to the pressure interface LS on the priority valve 3 is reduced, at this time, under the action of the pressure at the hydraulic oil input port P1 on the priority valve 3, the opening state of the spool of the priority valve 3 can be increased, so that more hydraulic oil flows through the negative flow control multi-way valve 5.

[0056] In this way, the priority valve group is formed by the priority valve 3 and the pressure control valve 4, and when the system is in the standby state, the variable pump 1 outputs the minimum displacement, and the hydraulic oil in the hydraulic control system is in a circulating flow state. When the priority valve 3 is in the normally open state, the energy loss of the hydraulic oil in the load sensing control valve 11 oil circuit in the standby state is avoided. When the load sensing control system in which the load sensing control valve 11 is located is working, the priority valve 3 is in the normally closed state, and the load sensing control system adjusts the opening state of the priority valve 3 according to the comparison between the load pressure and the pressure of the hydraulic oil input port P1 of the priority valve 3. After the priority valve 3 is opened, the flow output of the variable pump 1 is controlled by the negative flow control valve 5 to adapt to the needs of the corresponding actuator. When the negative flow control system is working, the priority valve 3 is in the communication state, so that the negative flow control system works normally.

[0057] The above setting mode realizes oil supply of the load sensing control system and the negative flow control system by the single pump, and improves the use efficiency of the pump. At the same time, since the traditional load sensing pump is cancelled, the equipment cost is greatly saved, and the arrangement difficulty of the hydraulic elements is reduced.

[0058] In the embodiment, the priority valve 3 and the pressure control valve 4 are both provided with a certain opening pressure value. When there is no load pressure, the priority valve 3 or the pressure control valve 4 can be opened when the pressure of the system reaches the set pressure value of the priority valve 3 or the pressure control valve 4.

[0059] It is emphasized that the opening and closing of the priority valve 3 are controlled by the pressure of the load sensing feedback port LS on the load sensing control valve 11 fed back to the pressure interface LS on the priority valve 3, the opening pressure of the valve core of the priority valve 3, and the pressure of the hydraulic oil input port P1 on the priority valve 3, so as to realize the conversion between the load sensing control system and the negative flow control system.

[0060] In some embodiments, the priority valve 3 is a proportional valve or a switch valve, and the valve core of the priority valve 3 is adjusted by electric control, hydraulic control or spring adjustment.

[0061] It is emphasized that in the load sensing control system, the opening pressure of the pressure control valve 4 is adjusted to reduce the main overflow pressure loss in the system. Under the condition of maintaining normal working state, the displacement of the variable pump 1 can be reduced to the minimum displacement required for work, and the energy consumption is greatly reduced.

[0062] In some embodiments, the pressure control valve 4 is a proportional valve or a switch valve, and the valve core of the pressure control valve 4 is adjusted by electric control, hydraulic control or spring adjustment.

[0063] As a preference, the priority valve 3 and the pressure control valve 4 can both be spool valves with spring adjustment, and when the system pressure reaches the spring preset pressure value of the priority valve 3 or the pressure control valve 4, the priority valve 3 or the pressure control valve 4 can be opened without load pressure.

[0064] In some embodiments, the hydraulic control system further comprises a hydraulic oil tank 2, and the adjusting oil path 7, the variable pump 1 and the pressure control valve 4 are all connected to the hydraulic oil tank 2. In addition, the output oil port of the negative flow control multi-way valve 5 is also connected to the hydraulic oil tank 2. The hydraulic oil tank 2 is used to provide hydraulic oil to the system and to recover hydraulic oil of the system to realize the circulating flow of the hydraulic oil in the system.

[0065] It should be noted that in the present embodiment, the load sensing control system is composed of the variable pump 1, the priority valve 3, the pressure control valve 4, the load sensing control multi-way valve 11, the second actuating element 12 and the hydraulic oil tank 2. The negative flow control system is composed of the variable pump 1, the priority valve 3, the pressure control valve 4, the negative flow control multi-way valve 5, the adjusting oil path 7, the bypass valve 8, the overflow valve 9, the throttle valve 10, the first actuating element 6 and the hydraulic oil tank 2.

[0066] The working process of the hydraulic control system provided by the present embodiment will be described in detail as follows:

[0067] Both the negative flow control system and the load sensing control system are in standby state: after the engine of the variable pump 1 is started, the variable pump 1 provides hydraulic oil, at this time, there is no load pressure (the first actuating element 6 and the second actuating element 12 are not working), the pressure of the load sensing feedback port LS on the load sensing control multi-way valve 11 fed back to the pressure interface LS on the priority valve 3 is zero, when the pressure of the hydraulic oil input port P1 on the priority valve 3 is greater than the spring preset pressure of the priority valve 3, the hydraulic oil pushes away the spool of the priority valve 3, the priority valve 3 is opened, the hydraulic oil output by the variable pump 1 flows through the negative flow control multi-way valve 5 and the adjusting oil path 7, under the action of the throttle valve 10, a certain pressure is generated and fed back to the control port of the variable pump 1 to reduce the hydraulic oil output of the variable pump 1, so that the variable pump 1 is in a low displacement state, the hydraulic oil returns to the hydraulic oil tank 2 through the throttle valve 10, thereby reducing the energy loss of the hydraulic control system, at the same time, the hydraulic oil does not flow through the load sensing control multi-way valve 11, thereby avoiding the increase of the energy loss of the hydraulic oil in the load sensing control system where the load sensing control multi-way valve 11 is located.

[0068] When the load-sensing control multi-way valve 11 is opened, the second actuating element 12 starts to act, and the pressure at the load-sensing feedback port LS of the load-sensing control multi-way valve 11 is not zero. At this time, the opening condition of the priority valve 3 is that the pressure at the hydraulic oil input port P1 is greater than the spring preset pressure of the priority valve 3 + the feedback pressure at the pressure interface LS. Under the joint action of the spring preset pressure and the feedback pressure at the pressure interface LS, the priority valve 3 is in a closed state, and the working pressure in the system changes with the load. When the hydraulic oil output flow of the variable pump 1 is too large, when the pressure at the hydraulic oil input port P1 of the priority valve 3 is greater than the spring preset pressure of the priority valve 3 + the feedback pressure at the pressure interface LS, the hydraulic oil pushes away the valve core of the priority valve 3, the priority valve 3 is opened, the excess hydraulic oil flows through the negative flow control multi-way valve 5, and generates a corresponding pressure through the regulating oil passage 7 composed of the bypass valve 8, the overflow valve 9 and the throttle valve 10, so as to adjust the hydraulic oil output of the variable pump 1, so that the hydraulic oil output of the variable pump 1 is in a state required by the load-sensing control system. When the pressure of the load-sensing control system reaches the set pressure of the pressure control valve 4, the pressure control valve 4 is opened, and the opening state of the priority valve 3 is adjusted, more hydraulic oil flows through the negative flow control multi-way valve 5, and generates a corresponding pressure through the regulating oil passage 7 composed of the bypass valve 8, the overflow valve 9 and the throttle valve 10, so that the displacement of the variable pump 1 is reduced to the minimum displacement, which not only reduces the energy loss of the hydraulic control system, but also plays a role in regulating the working pressure of the entire load-sensing control system.

[0069] When the system receives the actuating instruction of the first actuating element 6, the negative flow control multi-way valve 5 is opened, the hydraulic oil provided by the variable pump 1 flows into the priority valve 3, when the pressure at the hydraulic oil input port P1 of the priority valve 3 is greater than the spring preset pressure of the priority valve 3, the hydraulic oil pushes away the valve core of the priority valve 3, the priority valve 3 is opened, the hydraulic oil flows from the priority valve 3 to the negative flow control multi-way valve 5 and the first actuating element 6, the first actuating element 6 starts to act, and the hydraulic oil does not flow through the regulating oil passage 7, the pressure of the regulating oil passage 7 is zero, so as to increase the hydraulic oil output of the variable pump 1, so that the variable pump 1 outputs hydraulic oil at the maximum displacement to meet the working needs of the first actuating element 6.

[0070] To sum up, the hydraulic control system provided by the application connects the negative flow control system in which the negative flow control valve 5 is located and the load-sensitive control system in which the load-sensitive control valve 11 is located in parallel, and realizes oil supply of the single pump to the negative flow control system and the load-sensitive control system, thereby reducing the use of one pump, improving the use efficiency of the pump, reducing the arrangement difficulty of the equipment, and reducing the equipment cost; at the same time, the energy loss of hydraulic oil in the load-sensitive control system in which the load-sensitive control valve 11 is located is avoided in the standby state of the system, the system pressure is regulated in the working state of the system, thereby reducing the energy loss of the hydraulic control system and the cost.

[0071] The engineering machine provided by the application comprises the hydraulic control system described in the specific embodiments; other parts of the engineering machine can refer to the prior art, and will not be expanded herein.

[0072] It should be noted that, in the present specification, the relationship terms such as first and second are only used to distinguish one entity from another entity, and do not necessarily require or imply any such actual relationship or order between the entities.

[0073] The principles and implementation manners of the application are described by using specific examples in the present specification, and the above description of the examples is only used to help understand the method of the application and the core idea thereof. It should be pointed out that, for ordinary skilled persons in the art, some improvements and modifications can be made to the application without departing from the principles of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A hydraulic control system for controlling the operation of a first actuator (6) and a second actuator (12), characterized in that, include: A variable displacement pump (1) is used to achieve variable flow output of hydraulic oil; The negative flow control multi-way valve (5) is connected to the first actuator (6); The regulating oil circuit (7) is connected to the negative flow control multi-way valve (5) and the variable pump (1) to provide feedback pressure to the variable pump (1) in order to regulate the hydraulic oil output of the variable pump (1); A load-sensitive control multi-way valve (11) is connected to the second actuator (12) and the variable pump (1), and the load-sensitive control multi-way valve (11) is provided with a load-sensitive feedback port; Priority valve (3) is provided with hydraulic oil inlet, hydraulic oil outlet and pressure interface. The hydraulic oil inlet is connected to the output port of the variable pump (1). The hydraulic oil outlet is connected to the input port of the negative flow control multi-way valve (5). The pressure interface is connected to the load sensitive feedback port. When the first actuator (6) and the second actuator (12) are not working, when the pressure at the hydraulic oil inlet is greater than the valve core opening pressure of the priority valve (3), the hydraulic oil pushes the valve core of the priority valve (3) from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve (5) and the regulating oil circuit (7) to reduce the hydraulic oil output of the variable pump (1); When the load-sensitive control multi-way valve (11) controls the second actuator (12) to work and the negative flow control multi-way valve (5) controls the first actuator (6) to not work, when the pressure at the hydraulic oil inlet is greater than the sum of the valve core opening pressure of the priority valve (3) and the pressure of the pressure port, the hydraulic oil pushes the valve core of the priority valve (3) from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve (5) and the regulating oil circuit (7) to adjust the hydraulic oil output of the variable pump (1) to the state required for the second actuator (12) to work; When the negative flow control multi-way valve (5) controls the first actuator (6) to work and the load sensitive control multi-way valve (11) controls the second actuator (12) to not work, when the pressure at the hydraulic oil inlet is greater than the valve core opening pressure of the priority valve (3), the hydraulic oil pushes the valve core of the priority valve (3) from the first working position to the second working position, so that the hydraulic oil flows through the negative flow control multi-way valve (5) and the first actuator (6), and the hydraulic oil does not flow through the regulating oil circuit (7), so as to increase the hydraulic oil output of the variable pump (1); It also includes a pressure control valve (4), which is connected to the oil circuit between the pressure interface and the load-sensitive feedback port. When the pressure of the load-sensitive control system where the load-sensitive control multi-way valve (11) is located reaches the set pressure of the pressure control valve (4), the pressure control valve (4) opens and adjusts the opening state of the priority valve (3) so that the hydraulic oil flows through the negative flow control multi-way valve (5) and the regulating oil circuit (7) to reduce the displacement of the variable pump (1) to a preset low value.

2. The hydraulic control system according to claim 1, characterized in that, The regulating oil circuit (7) is provided with a regulating valve assembly, which is used to regulate the hydraulic oil output of the variable pump (1). The regulating valve assembly includes: A bypass valve (8) is connected to the output port of the negative flow control multi-way valve (5); Throttle valve (10), connected to the bypass valve (8), is used to control the hydraulic oil flow rate of the regulating oil circuit (7).

3. The hydraulic control system according to claim 2, characterized in that, The regulating valve assembly also includes an overflow valve (9), which is connected in parallel with the throttle valve (10).

4. The hydraulic control system according to claim 1, characterized in that, It also includes a hydraulic oil tank (2), and the regulating oil circuit (7), the variable pump (1) and the pressure control valve (4) are all connected to the hydraulic oil tank (2).

5. The hydraulic control system according to claim 1, characterized in that, The pressure control valve (4) is a proportional valve or a switching valve, and the valve core of the pressure control valve (4) is adjusted by electric control, hydraulic control or spring control.

6. The hydraulic control system according to claim 1, characterized in that, The priority valve (3) is a proportional valve or a switching valve, and the valve core of the priority valve (3) is adjusted by electric control, hydraulic control or spring control.

7. The hydraulic control system according to claim 1, characterized in that, The priority valve (3) is a two-position two-way valve.

8. The hydraulic control system according to claim 1, characterized in that, The negative flow control multi-way valve (5) is a three-position eight-way valve.

9. An engineering machinery, characterized in that, Includes the hydraulic control system as described in any one of claims 1-8.

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