Hydraulic system and excavator

Abstract

The application provides a hydraulic system for the technical field of excavators, in particular to a hydraulic system, comprising an actuator, a spool valve, a pressure sensor and a control unit, the pressure sensor can detect the pressure of the rod cavity, the rodless cavity and the piston rod end of the actuator; the control unit can accept the pressure signal of the pressure sensor and control the switching of the differential connection oil passage between the on / off state, the flow regulation in the on state and / or the flow regulation of the oil return oil passage. The application also provides an excavator comprising the above hydraulic system. The above hydraulic system and excavator intelligently control the differential connection on / off according to the pressure signal of the pressure sensor, improve the cylinder pushing force, intelligently control the second oil passage flow to change the back pressure of the oil return, reduce the energy consumption, and improve the working efficiency of the excavator and reduce the energy consumption.

Description

TECHNICAL FIELD

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

[0002] In the prior art, when the load of an actuator is an overrunning load, the hydraulic control system works in a low-pressure regeneration mode, the inlet and outlet of the hydraulic actuator are simultaneously connected to a low-pressure return oil circuit, forming a differential connection, at this time the hydraulic actuator is driven to move by the overrunning load without the need for the pump to provide flow. Although the system saves energy in this mode, when the return oil passes through the control valve into the low-pressure cavity of the hydraulic actuator, it is easy to produce cavitation through the pressure loss along the way and the valve port pressure loss. In addition, the size of the return oil back pressure is fixed and cannot be adjusted, the pressure loss is large, and the energy consumption is high. SUMMARY

[0003] Therefore, the present application provides a hydraulic system and an excavator, which intelligently controls the on-off of the differential connection according to the pressure signal of the pressure sensor through the control unit, improves the cylinder pushing force, intelligently controls the second oil passage flow to change the size of the return oil back pressure, reduces the energy consumption, and improves the working efficiency of the excavator.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0005] A hydraulic system, comprising:

[0006] An actuator, comprising a rod cavity, a rodless cavity and a piston rod;

[0007] A spool valve; comprising an oil inlet P, a return oil port T, a working oil port A and a working oil port B; a first oil passage is provided between the oil inlet P and the working oil port A, a second oil passage is provided between the return oil port T and the working oil port B, a differential connection oil passage is provided between the first oil passage and the second oil passage, the differential connection oil passage can be switched between the on / off state and the flow is adjustable in the on state, and the flow of the second oil passage is adjustable;

[0008] A pressure sensor, comprising a first pressure sensor, a second pressure sensor and a third pressure sensor, the first pressure sensor is used to detect the pressure in the rodless cavity, the second pressure sensor is used to detect the pressure in the rod cavity, and the third pressure sensor is used to detect the pressure on the end of the piston rod;

[0009] A control unit capable of receiving the pressure signal fed back by the first pressure sensor, the second pressure sensor and the third pressure sensor and controlling the switching of the differential connection oil passage between the on / off state and the flow adjustment in the on state according to the pressure signal, and / or adjusting the flow of the second oil passage.

[0010] Optionally, a proportional electromagnetic valve c is arranged on the differential connection oil passage, a proportional electromagnetic valve d is arranged on the second oil passage, the proportional electromagnetic valve c and the proportional electromagnetic valve d are electrically connected to the control unit, the control unit can control the proportional electromagnetic valve c to control the switching of the differential connection oil passage between the on / off state and the flow regulation in the on state, and the control unit can control the proportional electromagnetic valve d to regulate the flow of the second oil passage.

[0011] Optionally, the proportional electromagnetic valve d is arranged downstream of the intersection point of the second oil passage and the differential connection oil passage.

[0012] Optionally, the proportional electromagnetic valve c includes two working positions of upper position and lower position, when the lower position is powered, the differential connection oil passage is connected by a throttle valve, and when the upper position is powered, the differential connection oil passage is cut off by a check valve.

[0013] Optionally, the proportional electromagnetic valve d includes two working positions of left position and right position, when the left position is powered, the second oil passage is always connected, and when the right position is powered, the second oil passage is connected by a throttle valve.

[0014] Optionally, when the first oil passage and the second oil passage are both connected, and the pressure values fed back by the first pressure sensor and the second pressure sensor are greater than 0 and the pressure value fed back by the third pressure sensor is equal to 0, the control unit switches the proportional electromagnetic valve c to the lower position powered state.

[0015] Optionally, the control unit switches the proportional electromagnetic valve d to the left position powered state.

[0016] Optionally, when the first oil passage and the second oil passage are both connected, and the pressure values fed back by the first pressure sensor and the second pressure sensor are greater than 0 and the pressure value fed back by the third pressure sensor is greater than 0, the control unit switches the proportional electromagnetic valve c to the upper position powered state.

[0017] Optionally, the control unit switches the proportional electromagnetic valve d to the right position powered state.

[0018] The application also provides a excavator comprising the hydraulic system.

[0019] The hydraulic system provided by the application sends the pressure signals collected at the rod cavity, the rodless cavity and the piston rod to the control unit, the control unit judges the load state of the piston rod according to the pressure signals, intelligently controls the flow of the differential connection on / off and the on state, improves the pushing force of the oil cylinder, and intelligently controls the flow of the second oil passage to change the back pressure size, thereby reducing energy consumption.

[0020] The excavator provided in this application uses the aforementioned hydraulic system, which can improve work efficiency and reduce energy consumption. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the hydraulic system of this application;

[0023] Figure 2 This is a schematic diagram of the slide valve of this application;

[0024] Figure 3 for Figure 2 A magnified schematic diagram of the oil circuit when the middle slide valve is in the right-hand energized operating position.

[0025] exist Figures 1-3 middle:

[0026] 1. Actuator; 11. Rodless chamber; 111. First pressure sensor; 12. Rod chamber; 121. Second pressure sensor; 13. Piston rod; 131. Third pressure sensor; 2. Spool valve; 21. Working port A; 22. Working port B; 23. Inlet port P; 24. Return port T; 31. Proportional solenoid valve c; 32. Proportional solenoid valve d; 4. Control unit; 51. First oil passage; 52. Second oil passage; 53. Differential connection oil passage; 54. Intersection of the second oil passage and the differential connection oil passage. Detailed Implementation

[0027] This application provides a hydraulic system and an excavator, in which the control unit intelligently controls the differential connection on and off based on the pressure signal from the pressure sensor, thereby increasing the cylinder thrust and intelligently controlling the flow rate of the second oil passage to change the magnitude of the return oil back pressure, thus reducing energy consumption and improving the working efficiency of the excavator.

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] like Figures 1-3 As shown, this application embodiment provides a hydraulic system, including:

[0030] The actuator 1, such as a cylinder, comprises a rod cavity 12, a rodless cavity 11 and a piston rod 13, the end of the piston rod 13 being connectable to a moving mechanism such as a digging arm of a excavator;

[0031] The spool valve 2, in this embodiment a three-position four-way valve, comprises an oil inlet P23, an oil return T24, a working oil port A21 and a working oil port B22; a first oil passage 51 is provided between the oil inlet P23 and the working oil port A21, and a second oil passage 52 is provided between the oil return T24 and the working oil port B22; the spool valve 2 comprises an a end on the left side and a b end on the right side; when the b end of the spool valve 2 receives a pressure signal, the spool valve 2 is in the right position; at this time, hydraulic oil passes through the first oil passage 51, i.e. passes through the oil inlet P23, the working oil port A21 in turn and enters the rodless cavity 11 of the cylinder, while the rod cavity 12 is extruded, and the hydraulic oil passes through the second oil passage 52, i.e. passes through the working oil port B22, the oil return T24 in turn and returns to the actuator 1;

[0032] A differential connection oil passage 53 is provided between the first oil passage 51 and the second oil passage 52, the differential connection oil passage 53 being switchable between an on / off state and the flow being adjustable in the on state, and the flow of the second oil passage 52 being adjustable;

[0033] The pressure sensor comprises a first pressure sensor 111, a second pressure sensor 121 and a third pressure sensor 131; the first pressure sensor 111 is used to detect the pressure in the rodless cavity 11, the second pressure sensor 121 is used to detect the pressure in the rod cavity 12, and the third pressure sensor 131 is used to detect the pressure on the end of the piston rod 13; when the piston rod 13 of the actuator 1 moves, the first pressure sensor 111 and the second pressure sensor 121 can detect the pressure; when the actuator 1 has a load, the third pressure sensor 131 can detect the pressure; when the actuator 1 is unloaded, the pressure detected by the third pressure sensor 131 is 0;

[0034] The control unit 4 can receive the pressure signals fed back by the first pressure sensor 111, the second pressure sensor 121 and the third pressure sensor 131 and control the switching of the differential connection oil passage 53 between the on / off state and the flow adjustment in the on state according to the pressure signals, and / or adjust the flow of the second oil passage 52.

[0035] The hydraulic system of the present application collects the pressure signals at the rod cavity 12, the rodless cavity 11 and the piston rod 13 and sends them to the control unit 4, which then judges the load state of the piston rod 13 according to the pressure signals and intelligently controls the on / off of the differential connection oil passage 53 and the flow in the on state to improve the pushing force of the cylinder and avoid the phenomenon of air suction, and intelligently controls the flow of the second oil passage 52 to change the size of the oil return back pressure and reduce energy consumption.

[0036] As shown in Figures 1-3 In a preferred embodiment, proportional electromagnetic valve c31 is arranged on differential connection oil passage 53, and proportional electromagnetic valve d32 is arranged on second oil passage 52, both of which are electrically connected to control unit 4, which can control proportional electromagnetic valve c31 to control the switching between on / off states of differential connection oil passage 53 and the flow regulation in the on state, and can control proportional electromagnetic valve d32 to regulate the flow of second oil passage 52.

[0037] In this embodiment, the control of proportional electromagnetic valve c31 on differential connection oil passage 53 by control unit 4 is used to control the switching between on / off states of differential connection oil passage 53 and the flow regulation in the on state; similarly, the control of proportional electromagnetic valve d32 on second oil passage 52 by control unit 4 is used to regulate the flow of second oil passage 52; wherein the control of control unit 4 on proportional electromagnetic valve c31 and proportional electromagnetic valve d32 includes the switching of the working position of the proportional electromagnetic valve and the regulation of the size of the throttle, etc.

[0038] As shown in Figure 3 In a preferred embodiment, proportional electromagnetic valve d32 is arranged downstream of the intersection 54 of second oil passage 52 and differential connection oil passage 53, i.e. between the intersection 54 of second oil passage 52 and differential connection oil passage 53 and the oil return port T24.

[0039] Since proportional electromagnetic valve d32 is arranged on second oil passage 52, if proportional electromagnetic valve d32 is arranged upstream of the intersection 54 of second oil passage 52 and differential connection oil passage 53, i.e. between working oil port B22 and the intersection 54 of second oil passage 52 and differential connection oil passage 53, it will be involved in the differential oil circuit and will affect the differential oil circuit, making the control of control unit 4 on the proportional electromagnetic valve more complex, therefore, in this embodiment, proportional electromagnetic valve d32 is arranged downstream of the intersection of second oil passage 52 and differential connection oil passage 53, and the back pressure is regulated by regulating the proportional electromagnetic valve, without affecting the differential oil circuit.

[0040] Specifically, as shown in Figure 3 In a preferred embodiment, proportional electromagnetic valve c31 includes two working positions, upper position and lower position, when the lower position is powered, differential connection oil passage 53 is connected by a throttle valve, and when the upper position is powered, differential connection oil passage 53 is cut off by a check valve.

[0041] According to the pressure signal of the pressure sensor, the control unit 4 controls the proportional electromagnetic valve c31 through the electrical signal and switches its working position. When the lower position is powered, the proportional electromagnetic valve c31 switches to the lower working position, the differential connection oil way 53 is connected by the throttle valve, and the flow size of the differential connection oil way 53 can be controlled by adjusting the throttle opening of the throttle valve; when the upper position is powered, the proportional electromagnetic valve c31 switches to the upper working position, the differential connection oil way 53 is cut off by the one-way valve, and thus the control unit 4 controls the proportional electromagnetic valve c31 through the electrical signal to realize the control of whether the differential connection works and the pressure loss size after the differential connection.

[0042] Similarly, as shown in Figure 3 In a preferred embodiment, the proportional electromagnetic valve d32 includes two working positions of left position and right position. When the left position is powered, the second oil way 52 is always connected; when the right position is powered, the second oil way 52 is connected by the throttle valve.

[0043] According to the pressure signal of the pressure sensor, the control unit 4 controls the proportional electromagnetic valve d32 through the electrical signal and switches its working position. When the left position is powered, the proportional electromagnetic valve d32 switches to the left working position, the second oil way 52 is always connected, and thus the "zero" back pressure oil return can be realized; when the right position is powered, the proportional electromagnetic valve d32 switches to the right working position, the second oil way 52 is connected by the throttle valve, and thus the flow size of the proportional electromagnetic valve d32 can be controlled by adjusting the throttle opening of the throttle valve, and thus the control unit 4 controls the proportional electromagnetic valve d32 through the electrical signal to control the back pressure size of the oil return.

[0044] In a preferred embodiment, when the first oil way 51 and the second oil way 52 are both connected, and the pressure values fed back by the first pressure sensor 111 and the second pressure sensor 121 are greater than 0 and the pressure value fed back by the third pressure sensor 131 is equal to 0, that is, when the pressure signal is obtained at the end of the spool valve 2b, the spool valve 2 is forced to be in the right working position, the hydraulic oil enters the rodless chamber 11 of the oil cylinder through the first oil way 51, the rod chamber 12 receives extrusion at this time, the hydraulic oil returns to the actuator 1 through the rod chamber 12, the working oil port B22 and the oil return port T24, and the machine is in the state of the empty load running stage, the control unit 4 switches the proportional electromagnetic valve c31 to the lower powered state.

[0045] At this moment, since the proportional electromagnetic valve c31 is switched to the lower powered state, that is, the differential connection oil way 53 is connected by the throttle valve, the part of the hydraulic oil flowing from the working oil port B22 to the oil return port T24 flows to the working oil port A21 through the differential connection oil way 53, supplements the oil inlet of the rodless chamber 11, and pushes the oil cylinder forward, but in order to avoid the suction of the piston rod 13 of the oil cylinder due to the too fast pushing speed, the size of the throttle opening of the proportional electromagnetic valve c31 can be controlled to realize the flow size of the hydraulic oil supplied to the rodless chamber 11 from the working oil port A21, and thus the suction is avoided.

[0046] Further, the control unit 4 switches the proportional electromagnetic valve d32 to the right energized state, so as to realize that the second oil passage 52 is connected by the throttle valve.

[0047] In this way, the hydraulic oil flowing from the working oil port B22 to the remaining part of the oil return port T24 can adjust the size of the throttle port of the throttle valve according to the actual working condition, so as to establish back pressure and assist the speed of differential connection oil supplement.

[0048] In a preferred embodiment, when the first oil passage 51 and the second oil passage 52 are both connected, and the pressure values fed back by the first pressure sensor 111 and the second pressure sensor 121 are greater than 0, and the pressure value fed back by the third pressure sensor 131 is greater than 0, the control unit 4 switches the proportional electromagnetic valve c31 to the upper energized state.

[0049] When the piston rod 13 of the actuator 1 touches the resistance generated by the action mechanism that needs to be pushed, the proportional electromagnetic valve c31 can be given a signal by the control unit 4 to be immediately in the upper position, and the differential connection oil passage 53 is blocked, at this moment, the piston rod 13 overcomes the resistance with the maximum thrust.

[0050] Further, the control unit 4 switches the proportional electromagnetic valve d32 to the left energized state, so as to realize that the second oil passage 52 is always connected.

[0051] The control unit 4 switches the proportional electromagnetic valve c31 to the upper energized state, that is, after the differential connection oil passage 53 is cut off by the one-way valve, in order to maximize the pushing force and reduce the hydraulic oil return pressure loss of the rodless cavity 11 of the oil cylinder, the second oil passage 52 is always connected to realize "zero" back pressure return, thereby reducing the energy loss of the oil cylinder in the whole process.

[0052] The working principle of the hydraulic system of the present application is as follows:

[0053] When the b end of the spool valve 2 receives a pressure signal, the spool valve 2 is forced to the right position, that is, the first oil passage 51 and the second oil passage 52 are both connected; hydraulic oil enters the rodless chamber 11 of the oil cylinder from the oil inlet P23 through the working oil port A21, and the hydraulic oil in the rod chamber 12 is pressed at this time, and the hydraulic oil returns to the oil return port T24 through the working oil port B22; at this time, the pressures of the first pressure sensor 111, the second pressure sensor 121 and the third pressure sensor 131 are detected respectively, and since the piston of the oil cylinder is in a moving state, the pressure values returned by the first pressure sensor 111 and the second pressure sensor 121 are both greater than 0, but if the front end of the piston rod 13 of the oil cylinder is not loaded with power, the pressure value detected by the third pressure sensor 131 is 0, indicating that the machine is in an unloaded running stage; in order to save energy, the control unit 4 can be used to judge at this time to energize the proportional electromagnetic valve c31 and make it in the lower position, that is, the differential connection oil passage 53 is connected through the throttle valve, and at this time the hydraulic oil in the rod chamber 12 of the oil cylinder flows to the working oil port A21 through the working oil port B22 and the proportional electromagnetic valve c31, and supplements the hydraulic oil in the rodless chamber 11 to push the piston rod 13 of the oil cylinder forward, but in order to avoid the piston rod 13 of the oil cylinder advancing too fast and causing air suction, the size of the throttle opening of the proportional electromagnetic valve c31 can be controlled to realize the flow of the hydraulic oil from the working oil port A21 to the rodless chamber 11, thereby avoiding air suction; at the same time, part of the hydraulic oil in the rod chamber 12 returns to the oil return port T24 through the working oil port B22 and the proportional electromagnetic valve d32, and the size of the throttle opening of the proportional electromagnetic valve d32 can be adjusted according to the actual working condition to establish back pressure and assist the speed of differential connection oil supplement.

[0054] When the piston rod 13 of the oil cylinder continues to advance and touches the action mechanism that needs to be pushed to generate resistance, the control unit 4 can send a control signal to the proportional electromagnetic valve c31 to make the proportional electromagnetic valve c31 in the upper position, thereby blocking the differential connection oil passage 53, and at this time the piston rod 13 overcomes the resistance with the maximum thrust; and in order to maximize the pushing force and reduce the return pressure loss of the hydraulic oil in the rod chamber 12 of the oil cylinder, the proportional electromagnetic valve d32 is in the left position to realize "zero" back pressure return, thereby reducing the energy loss of the oil cylinder in the whole process.

[0055] The application also provides a excavator using the hydraulic system, which can improve the working efficiency and reduce the energy consumption.

[0056] The basic principles of the application are described above in combination with specific embodiments, but it should be pointed out that the advantages, advantages and effects mentioned in the application are only examples and cannot be considered as the must-have of each embodiment of the application. In addition, the above specific details are only for the purpose of example and understanding, and the application is not limited to the above specific details.

[0057] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply that the connection, arrangement, configuration must be as shown in the block diagrams. These devices, apparatuses, equipment, systems can be connected, arranged, configured in any way as those skilled in the art will recognize. Words such as "include", "contain", "have", and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "or", and can be used interchangeably, unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0058] It should also be noted that in the devices, apparatuses and methods of the present application, each component or each step can be decomposed or recombined. These decompositions or recombinations should be considered as equivalent solutions of the present application.

[0059] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the present application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0060] It should be understood that the adjectives "first", "second", "third", "fourth", "fifth" and "sixth" used in the embodiments of the present application are only used for more clearly describing the technical solutions, and cannot be used to limit the protection scope of the present application.

[0061] The above description has been given for the purpose of illustration and description. Furthermore, this description does not intend to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A hydraulic system, characterized in that, include: The actuator includes a rod chamber, a rodless chamber, and a piston rod; slide valve; Including oil inlet P, oil return T, working oil inlet A, and working oil inlet B; A first oil passage is provided between the oil inlet P and the working oil port A, and a second oil passage is provided between the oil return port T and the working oil port B. A differential connection oil passage is provided between the first oil passage and the second oil passage. The differential connection oil passage can be switched between on / off states and the flow rate is adjustable when it is on. The flow rate of the second oil passage is also adjustable. The pressure sensor includes a first pressure sensor, a second pressure sensor, and a third pressure sensor. The first pressure sensor is used to detect the pressure in the rodless chamber, the second pressure sensor is used to detect the pressure in the rod chamber, and the third pressure sensor is used to detect the pressure on the end of the piston rod. The control unit can receive pressure signals from the first pressure sensor, the second pressure sensor and the third pressure sensor, and control the differential connection oil passage to switch between on / off states and adjust the flow rate when on state according to the pressure signals, and / or adjust the flow rate of the second oil passage. A proportional solenoid valve c is provided on the differential connection oil passage, and a proportional solenoid valve d is provided on the second oil passage. Both the proportional solenoid valve c and the proportional solenoid valve d are electrically connected to the control unit. The control unit can control the proportional solenoid valve c to control the switching of the differential connection oil passage between the on / off state and the flow rate adjustment when it is on. The control unit can control the proportional solenoid valve d to adjust the flow rate of the second oil passage. The proportional solenoid valve c has two working positions: an upper position and a lower position. When the lower position is energized, the differential connection oil passage is connected by a throttle valve. When the upper position is energized, the differential connection oil passage is cut off by a check valve. The proportional solenoid valve d has two working positions: a left position and a right position. When the left position is energized, the second oil passage is normally open. When the right position is energized, the second oil passage is connected by a throttle valve.

2. The hydraulic system according to claim 1, characterized in that, The proportional solenoid valve d is located downstream of the intersection of the second oil passage and the differential connection oil passage.

3. The hydraulic system according to claim 1, characterized in that, When both the first oil passage and the second oil passage are connected, and the pressure values ​​fed back by the first pressure sensor and the second pressure sensor are greater than 0 and the pressure value fed back by the third pressure sensor is equal to 0, the control unit switches the proportional solenoid valve c to the lower energized state.

4. The hydraulic system according to claim 3, characterized in that, The control unit switches the proportional solenoid valve d to the left-hand energized state.

5. The hydraulic system according to claim 1, characterized in that, When both the first oil passage and the second oil passage are connected, and the pressure values ​​fed back by the first pressure sensor and the second pressure sensor are greater than 0, and the pressure value fed back by the third pressure sensor is greater than 0, the control unit switches the proportional solenoid valve c to the upper-level energized state.

6. The hydraulic system according to claim 5, characterized in that, The control unit switches the proportional solenoid valve d to the right-hand energized state.

7. An excavator, characterized in that, Includes the hydraulic system described in any one of claims 1-6.

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