Boom hydraulic system and excavator

Abstract

The embodiment of the application discloses a boom hydraulic system and a excavator. The boom hydraulic system comprises two explosion-proof valves, two oil cylinders, an oil transmission module, a pressure compensation acquisition module, a hydraulic control module, an oil transmission control module and a controller. The rodless cavity of each oil cylinder is communicated with the oil outlet of an explosion-proof valve. The oil inlet of each explosion-proof valve is communicated with the first oil transmission path port of the oil transmission module. The rod cavity of each oil cylinder and the oil return port of each explosion-proof valve are communicated with the second oil transmission path port of the oil transmission module. The oil transmission control module is communicated with the oil transmission module. The hydraulic control module is communicated with the control port of the explosion-proof valve. The pressure detection ports of the two explosion-proof valves are communicated through the pressure compensation acquisition module. The oil transmission module, the pressure compensation acquisition module and the hydraulic control module are connected with the controller. The scheme can avoid the occurrence of unbalanced load of the two oil cylinders controlling the boom. The boom can be locked at a fixed position in time when the boom runs in failure, thereby improving the stability and safety of the boom hydraulic system.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, and more particularly to a boom hydraulic system and an excavator. Background Technology

[0002] In existing technologies, explosion-proof valve hydraulic systems are prone to leakage in the boom cylinder. For example, when the explosion-proof valve hydraulic system simultaneously applies pilot oil from the pilot pump to the control end of the explosion-proof valve's on / off valve and the lowering control end of the main valve's boom coupling valve core, the on / off valve needs to be opened while controlling the boom's descent. This means that while lowering the boom, the oil in the rodless chamber needs to return through the on / off valve. However, the pilot pressure P1 that moves the main valve's boom coupling valve core and the unlocking pressure P2 of the explosion-proof valve's on / off valve are usually not equal. Let's assume that the unlocking pressure P2 of the explosion-proof valve's on / off valve is greater than the pilot pressure P1 that moves the main valve's boom coupling valve core. When the pilot pressure reaches the pilot pressure P1 required to move the main valve boom coupling valve core, the main valve boom coupling valve core will begin to move, and the high-pressure oil from the main pump will enter the rod chamber of the boom cylinder. However, at this time, the pilot pressure is less than the unlocking pressure P2 of the on / off valve in the explosion-proof valve, so the on / off valve of the explosion-proof valve cannot be opened. Obviously, the rodless chamber of the boom cylinder cannot return oil, which will cause the pressure in the rodless chamber of the cylinder to rise. When the pilot pressure rises to the unlocking pressure P2 of the on / off valve in the explosion-proof valve, the on / off valve of the explosion-proof valve opens, allowing the high-pressure oil in the rodless chamber to return oil through the on / off valve of the explosion-proof valve, thereby reducing the pressure in the rodless chamber of the cylinder.

[0003] Obviously, as the pilot pressure gradually rises from the pilot pressure P1 that moves the main valve boom and valve core to the unlocking pressure P2 of the on / off valve in the explosion-proof valve, a certain pressure fluctuation will occur in the cylinder. This pressure fluctuation and impact will cause leakage in the cylinder and reduce the reliability of the explosion-proof valve hydraulic system. Summary of the Invention

[0004] This invention provides a boom hydraulic system and an excavator to improve the reliability of the boom hydraulic system.

[0005] In a first aspect, embodiments of the present invention provide a boom hydraulic system, which includes two explosion-proof valves, two oil cylinders, an oil delivery module, a pressure compensation acquisition module, a hydraulic control module, an oil delivery control module, and a controller;

[0006] Each of the cylinders has its rodless chamber connected to the outlet of an explosion-proof valve, and each explosion-proof valve has its inlet connected to the first oil delivery path of the oil delivery module. The rod chambers of both cylinders and the return port of the explosion-proof valve are connected to the second oil delivery path of the oil delivery module. The oil delivery control module is connected to the oil delivery module and controls the oil delivery module to connect either the first or second oil delivery path for oil delivery. The hydraulic control module is connected to the control port of the explosion-proof valve and adjusts the pressure at the control port of the explosion-proof valve. The pressure detection ports of the two explosion-proof valves are connected to the pressure compensation and acquisition module, which balances the hydraulic pressure of the two explosion-proof valves and detects the hydraulic pressure of the explosion-proof valves. The oil delivery module, the pressure compensation and acquisition module, and the hydraulic control module are all connected to the controller, which controls the oil delivery volume of the oil delivery module or adjusts the pressure at the control port of the explosion-proof valve based on the hydraulic pressure of the explosion-proof valve.

[0007] Optionally, the pressure compensation acquisition module includes a pressure sensor and a pressure compensation hydraulic pipe;

[0008] The pressure detection ports of the two explosion-proof valves are connected through the pressure compensation hydraulic pipe, which is used to balance the hydraulic pressure of the two explosion-proof valves.

[0009] The pressure sensor is connected to the pressure detection port, which is used to detect the hydraulic pressure of the explosion-proof valve.

[0010] Optionally, the oil delivery module includes a boom-connected directional valve and a main pump;

[0011] The main pump is connected to the oil inlet of the boom reversing valve, the first oil port of the boom reversing valve serves as the first oil delivery path port, and the second oil port of the boom reversing valve serves as the second oil delivery path port.

[0012] The oil delivery control module is connected to the pilot port of the boom coupling directional valve. The oil delivery control module is used to control the hydraulic pressure of the pilot port of the boom coupling directional valve, thereby controlling the oil delivery through the first or second oil port of the boom coupling directional valve.

[0013] The controller is connected to the main pump and is used to control the oil delivery rate of the main pump based on the hydraulic pressure of the explosion-proof valve.

[0014] Optionally, the oil delivery control module includes a proportional directional valve and a proportional valve;

[0015] The boom coupling directional valve also includes a first pilot port and a second pilot port;

[0016] The first delivery port of the proportional directional valve is connected to the first pilot port, the second delivery port of the proportional directional valve is connected to the second pilot port, the proportional valve is connected to the proportional directional valve, and the proportional valve is used to adjust the proportional directional valve to deliver pilot oil to the first pilot port or the second pilot port, so as to adjust the hydraulic pressure of the first pilot port or the second pilot port.

[0017] Optionally, the hydraulic control module includes a proportional pressure reducing valve and a solenoid switching valve;

[0018] The proportional pressure reducing valve is connected to the electromagnetic switch valve, and the electromagnetic switch valve is connected to the control port of each of the explosion-proof valves. Both the proportional pressure reducing valve and the electromagnetic switch valve are connected to the controller. The controller is used to control the hydraulic pressure supplied by the proportional pressure reducing valve to the pilot oil of the electromagnetic switch valve, and the controller is used to control the hydraulic pressure output by the electromagnetic switch valve to the pilot oil of the control port.

[0019] Optionally, the boom hydraulic system also includes a pilot pump;

[0020] Both the hydraulic control module and the oil delivery control module are connected to the pilot pump, which is used to deliver pilot oil to the hydraulic control module or the oil delivery control module.

[0021] Optionally, the boom hydraulic system also includes a pilot filter;

[0022] The pilot filter is connected to the pilot pump, and both the hydraulic control module and the oil delivery control module are connected to the pilot filter. The pilot filter is used to filter the pilot oil.

[0023] Optionally, the boom hydraulic system also includes an oil tank;

[0024] Each of the explosion-proof valves, the oil delivery module, the hydraulic control module, and the oil delivery control module is connected to the oil tank. The oil tank is used to supply oil to the oil delivery module, the hydraulic control module, and the oil delivery control module. The oil tank is also used to receive the return oil from the explosion-proof valves, the oil delivery module, the hydraulic control module, and the oil delivery control module.

[0025] Optionally, the boom hydraulic system also includes a check valve;

[0026] The main pump is connected to the check valve and the boom directional valve. The check valve is used to control the oil delivery direction between the main pump and the boom directional valve.

[0027] Secondly, embodiments of the present invention also provide an excavator that includes the boom hydraulic system provided in the embodiments of the present invention.

[0028] The boom hydraulic system provided in this invention can control the oil delivery module to supply oil to the rod chamber or rodless chamber of the cylinder through different oil delivery paths, thereby achieving lifting and lowering control of the boom. The pressure compensation and acquisition module not only balances the hydraulic pressure of the two explosion-proof valves to eliminate uneven load control of the boom due to flow differences between the two cylinders, but also monitors the hydraulic pressure of the explosion-proof valves in real time and provides timely feedback to the controller. This allows the controller to adjust the operation of the boom hydraulic system based on the hydraulic pressure of the explosion-proof valves, thus improving the stability of the boom hydraulic system. Under the control of the controller, the hydraulic control module reduces pressure fluctuations and pressure shocks to the cylinders, thereby reducing the cylinder leakage failure rate and further improving the stability of the boom hydraulic system. Furthermore, the boom hydraulic system, composed of two explosion-proof valves, two cylinders, an oil delivery module, a pressure compensation and acquisition module, a hydraulic control module, an oil delivery control module, and a controller, can promptly lock the boom in a fixed position in cases of boom overload, boom lifting oil inlet pipe rupture, and boom lowering oil return pipe rupture, improving the safety of the boom hydraulic system. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of a boom hydraulic system provided in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a boom hydraulic system provided in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] To better explain the solution of the present invention, the structure of existing explosion-proof valves will be briefly described first.

[0036] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the explosion-proof valve includes a one-way valve 111, an on / off valve 112, a pressure detection port E, an overload relief valve 113, an oil outlet C, an oil inlet A, an oil return port R, an oil drain port D, and a control port P.

[0037] The oil inlet A is connected to the oil outlet C via a one-way valve 111, meaning that high-pressure oil flowing into the oil inlet A can be delivered to the oil outlet C, but high-pressure oil from the oil outlet C cannot be delivered to the oil inlet A. The oil outlet C is connected to the return port R and the oil inlet A via a shut-off valve 112. When the hydraulic pressure at the control port P reaches a certain value, the shut-off valve 112 is activated, allowing the high-pressure oil from the oil outlet C to flow back to the return port R or the oil inlet A through the shut-off valve 112. When the hydraulic pressure at the control port P does not reach a certain value, the shut-off valve 112 is deactivated, preventing the high-pressure oil from the oil outlet C from flowing back to the return port R or the oil inlet A through the shut-off valve 112. The oil outlet C is also connected to the return oil port R and the inlet oil port A via the overload relief valve 113. When the overload relief valve 113 is open, the oil at the oil outlet C can flow back to the return oil port R or the inlet oil port A through the overload relief valve 113; when the overload relief valve 113 is closed, the high-pressure oil at the oil outlet C cannot flow back to the return oil port R or the inlet oil port A through the overload relief valve 113. When the explosion-proof valve needs maintenance, the high-pressure oil inside the explosion-proof valve can be discharged through the drain port D.

[0038] This invention provides a boom hydraulic system, which includes two explosion-proof valves with the above-described structure. The specific structure of the explosion-proof valves will not be described again in the following embodiments. The structure and working principle of the boom hydraulic system are described in detail below.

[0039] Figure 2This is a schematic diagram of a boom hydraulic system provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the boom hydraulic system includes two explosion-proof valves 110, two oil cylinders 120, an oil delivery module 130, a pressure compensation acquisition module 140, a hydraulic control module 150, an oil delivery control module 160, and a controller 170.

[0040] Each cylinder 120 has its rodless chamber connected to the outlet C of an explosion-proof valve 110. The inlet A of each explosion-proof valve 110 is connected to the first oil delivery path of the oil delivery module 130. The rod chambers of both cylinders 120 and the return port R of the explosion-proof valve 110 are connected to the second oil delivery path of the oil delivery module 130. The oil delivery control module 160 is connected to the oil delivery module 130 and is used to control the oil delivery module 130 to open either the first or second oil delivery path for oil delivery. The hydraulic control module 150 is connected to the control port P of the explosion-proof valve 110. The pressure at the control port P of the explosion-proof valve 110 is adjusted. The pressure detection ports E of the two explosion-proof valves 110 are connected through the pressure compensation and acquisition module 140. The pressure compensation and acquisition module 140 is used to balance the hydraulic pressure of the two explosion-proof valves 110 and detect the hydraulic pressure of the explosion-proof valves 110. The oil delivery module 130, the pressure compensation and acquisition module 140, and the hydraulic control module 150 are all connected to the controller 170. The controller 170 is used to control the oil delivery volume of the oil delivery module 130 or to control the hydraulic control module 150 to adjust the pressure at the control port P of the explosion-proof valve 110 according to the hydraulic pressure of the explosion-proof valve 110.

[0041] Among them, the explosion-proof valve 110 plays a crucial role in ensuring the safe operation of excavators and other construction machinery. When the hydraulic line from the high-pressure oil supply to the cylinder 120 ruptures or the pipe joint becomes loose due to frequent boom movements, the explosion-proof valve 110 can lock the cylinder 120 in a fixed position to prevent the boom from falling rapidly and causing a safety accident. The oil delivery module 130 provides power to the cylinder 120, enabling it to control the boom's raising or lowering. The pressure compensation and acquisition module 140 balances the hydraulic pressure of the two explosion-proof valves 110 to eliminate the phenomenon of uneven load control of the boom by the two cylinders 120 due to flow differences; the pressure compensation and acquisition module 140 can also detect the hydraulic pressure of the explosion-proof valves 110 and provide real-time feedback to the controller 170, so that the controller 170 can adjust the operation of the boom hydraulic system in real time based on the hydraulic pressure of the explosion-proof valves 110. The oil delivery control module 160 can control the oil delivery module 130 to open different oil delivery paths to deliver oil to the rod chamber or rodless chamber of the cylinder 120. For example, the oil supply control module 160 can open the oil supply path port connected to the rod chamber of the cylinder 120, supplying oil to the rod chamber of the cylinder 120; the oil supply control module 160 can also open the oil supply path port connected to the explosion-proof valve 110, supplying oil to the rodless chamber of the cylinder 120 through the explosion-proof valve 110. The hydraulic control module 150 can adjust the pressure of the control port P of the explosion-proof valve 110, ensuring that while the cylinder 120 controls the boom to descend, the oil in the rodless chamber of the cylinder 120 can return through the explosion-proof valve 110 (returning oil refers to the oil flowing back into the oil tank). The controller 170 can control the oil supply volume of the oil supply module 130 based on the hydraulic pressure of the explosion-proof valve 110, or control the hydraulic control module 150 to adjust the pressure of the control port P of the explosion-proof valve 110.

[0042] The boom hydraulic system operates under the following conditions: 1) Normal boom raising; 2) Normal boom lowering; 3) Boom holding; 4) Boom raising inlet line rupture; 5) Boom lowering return line rupture. The following describes the operation of the boom hydraulic system under these conditions:

[0043] 1) During normal boom raising, the boom hydraulic system operates as follows: the oil supply control module 160 controls the first oil supply path port of the oil supply module 130 to open. The high-pressure oil output from the first oil supply path port of the oil supply module 130 is input into the rodless chamber of the cylinder 120 through the inlet A and outlet C of the explosion-proof valve 110. The high pressure in the rodless chamber flows into the oil supply module 130 for return oil. When the boom is overloaded during raising, the hydraulic pressure in the rodless chamber of the cylinder 120 will increase. At this time, the rodless chamber of the cylinder 120 will return oil through the overload relief valve of the explosion-proof valve 110. At the same time, the controller 170 will control the oil supply module 130 to reduce the oil supply based on the hydraulic pressure of the explosion-proof valve 110 collected by the pressure compensation acquisition module 140, thereby providing double protection against boom overload.

[0044] 2) During normal boom descent, the boom hydraulic system operates as follows: the oil supply control module 160 controls the second oil supply path port of the oil supply module 130 to open, and the high-pressure oil output from the second oil supply path port of the oil supply module 130 is input into the rod chamber of the cylinder 120. At this time, the controller 170, based on the hydraulic pressure of the explosion-proof valve 110 collected by the pressure compensation acquisition module 140, controls the hydraulic control module 150 to adjust the pressure of the control port P of the explosion-proof valve 110, so that the oil in the rodless chamber of the cylinder 120 can flow back to the oil supply module 130 through the oil inlet A of the explosion-proof valve 110 for return oil. The boom descent speed can be adjusted by the hydraulic control module 150. When the hydraulic control module 150 increases the pressure of the control port P of the explosion-proof valve 110, the boom descent speed increases; when the hydraulic control module 150 decreases the pressure of the control port P of the explosion-proof valve 110, the boom descent speed decreases.

[0045] 3) During boom holding, the boom hydraulic system operates as follows: Boom holding refers to fixing the boom in a certain position after it has been raised to a certain position, preventing it from automatically lowering. At this time, the explosion-proof valve 110 functions as a boom holder. When the boom is raised to a certain position, the first oil supply path of the oil supply module 130 stops supplying oil to the rodless chamber of the cylinder 120. Therefore, the oil in the rodless chamber of the cylinder 120 cannot return through the explosion-proof valve 110, thus achieving boom holding. If the load is too large or the boom is subjected to severe impact or vibration during boom holding, the pressure in the rodless chamber of the cylinder 120 will increase. When the pressure in the rodless chamber of the cylinder 120 exceeds a certain value, the overflow valve of the explosion-proof valve 110 will open, allowing the oil in the rodless chamber of the cylinder 120 to overflow back to the oil tank, thereby improving the stability of the boom hydraulic system.

[0046] 4) When the boom lifting oil inlet pipe bursts, the boom hydraulic system operates as follows: If the oil inlet pipe suddenly bursts, the oil delivery module 130 cannot supply oil to the rodless chamber of the cylinder 120. The first oil delivery path port of the oil delivery module 130 stops supplying oil to the rodless chamber of the cylinder 120, and controls the oil in the rodless chamber of the cylinder 120 to not return through the explosion-proof valve 110, thereby controlling the boom to lock in the position it was in when the pipe burst, preventing the boom from rapidly descending due to the pipe burst.

[0047] 5) When the boom descent return oil line bursts, the boom hydraulic system operates as follows: At the instant the boom descent return oil line bursts, under the control of the hydraulic control module 150, the flow rate of oil in the rodless chamber of cylinder 120 through the explosion-proof valve 110 will increase sharply, that is, the flow rate from the outlet C to the inlet A of the explosion-proof valve 110 will increase sharply. The pressure compensation acquisition module 140 will detect the sharp rise in hydraulic pressure of the explosion-proof valve 110, and the controller 170 will cut off the pressure regulation of the control port P of the explosion-proof valve 110 by the hydraulic control module 150 based on the sharp rise in hydraulic pressure of the explosion-proof valve 110, thereby cutting off the return oil in the rodless chamber of cylinder 120, thus preventing oil leakage and preventing outside air from entering the cylinder 120 and damaging the boom hydraulic system.

[0048] The boom hydraulic system provided in this embodiment of the invention can control the oil delivery module 130 to supply oil to the rod chamber or rodless chamber of the cylinder 120 through different oil delivery path ports via the oil delivery control module 160, thereby realizing the lifting and lowering control of the boom by the cylinder 120. The pressure compensation acquisition module 140 can not only balance the hydraulic pressure of the two explosion-proof valves 110 to eliminate the phenomenon of uneven load control of the boom caused by the flow difference between the two cylinders 120, but also detect the hydraulic pressure of the explosion-proof valves 110 in real time and provide timely feedback to the controller 170. This allows the controller 170 to adjust the operation of the boom hydraulic system in real time according to the hydraulic pressure of the explosion-proof valves 110, thereby improving the stability of the boom hydraulic system. Under the control of the controller 170, the hydraulic control module 150 can reduce the pressure fluctuation and pressure shock of the cylinder 120, thereby reducing the leakage failure rate of the cylinder 120 and further improving the stability of the boom hydraulic system. In addition, the boom hydraulic system, which consists of two explosion-proof valves 110, two oil cylinders 120, an oil delivery module 130, a pressure compensation acquisition module 140, a hydraulic control module 150, an oil delivery control module 160, and a controller 170, can lock the boom in a fixed position in a timely manner in the event of boom overload, boom lifting oil inlet pipe rupture, or boom lowering oil return pipe rupture, thereby improving the safety of the boom hydraulic system.

[0049] Exemplarily, based on the above embodiments, Figure 3 This is a schematic diagram of a boom hydraulic system provided in an embodiment of the present invention, characterized in that, as Figure 3 As shown, the pressure compensation acquisition module 140 includes a pressure sensor 141 and a pressure compensation hydraulic pipe 142; the pressure detection ports E of the two explosion-proof valves 110 are connected through the pressure compensation hydraulic pipe 142, which is used to balance the hydraulic pressure of the two explosion-proof valves 110; the pressure sensor 141 is connected to the pressure detection port E, which is used to detect the hydraulic pressure of the explosion-proof valves 110.

[0050] In existing technologies, it is difficult to achieve synchronization of boom movement when multiple hydraulic cylinders 120 simultaneously control it. However, in excavators, typically two hydraulic cylinders 120 control the lifting and lowering of one boom. When the boom lowers, if the hydraulic pressure in the rodless chambers of the two cylinders 120 differs, it will cause a difference in the return flow rate of the rodless chambers, easily leading to uneven load when the cylinders 120 control the boom lowering. Similarly, when the boom rises, if the inlet flow rate of the rodless chambers of the two cylinders 120 differs, it will cause a difference in the hydraulic pressure in the rodless chambers, easily leading to uneven load when the cylinders 120 control the boom rising. To address these issues, this patent adds a pressure-compensating hydraulic pipe 142 connecting the pressure detection ports E of the two explosion-proof valves 110 to balance the hydraulic pressure of the two explosion-proof valves 110. This ensures that the rodless chambers of the two cylinders 120 have the same hydraulic pressure and flow rate, thereby synchronizing the boom movement controlled by the two cylinders 120 during lifting and lowering, thus avoiding uneven load.

[0051] Based on the above embodiments, alternatively, refer to the following: Figure 3 The oil delivery module 130 includes a boom-connected directional valve 131 and a main pump 132. The main pump 132 is connected to the oil inlet A of the boom-connected directional valve 131. The first oil port of the boom-connected directional valve 131 serves as the first oil delivery path port, and the second oil port of the boom-connected directional valve 131 serves as the second oil delivery path port. The oil delivery control module 160 is connected to the pilot port of the boom-connected directional valve 131. The oil delivery control module 160 is used to control the hydraulic pressure of the pilot port of the boom-connected directional valve 131, thereby controlling the oil delivery through the first or second oil port of the boom-connected directional valve 131. The controller 170 is connected to the main pump 132. The controller 170 is used to control the oil delivery volume of the main pump 132 according to the hydraulic pressure of the explosion-proof valve 110.

[0052] Specifically, the first port of the boom-connecting directional valve 131 is connected to the inlet A of each explosion-proof valve 110, and the return port R of each explosion-proof valve 110 and the rod chamber of each cylinder 120 are connected to the second port of the boom-connecting directional valve 131. Assuming the hydraulic pressure at the pilot port of the boom-connecting directional valve 131 reaches a first threshold, the boom-connecting directional valve 131 opens the first port; when the hydraulic pressure at the pilot port of the boom-connecting directional valve 131 reaches a second threshold, the boom-connecting directional valve 131 opens the second port. When the first port is open, the oil output from the first port is output to the rodless chamber of the cylinder 120 through the inlet A and outlet C of the explosion-proof valve 110, and the oil in the rod chamber of the cylinder 120 flows back. At this time, the cylinder 120 can control the boom to rise. When the second oil port is open, the oil output from the second oil port is output to the rod chamber of the cylinder 120, and the oil in the rodless chamber of the cylinder 120 flows back through the on / off valve of the explosion-proof valve 110. At this time, the cylinder 120 can control the boom to descend.

[0053] In the event of an overload during boom lifting, the hydraulic pressure in the rodless chamber of cylinder 120 will increase. At this time, the rodless chamber of cylinder 120 will return oil through the overload relief valve of explosion-proof valve 110. Simultaneously, controller 170 will control oil delivery module 130 to reduce oil delivery based on the hydraulic pressure of explosion-proof valve 110 collected by pressure compensation acquisition module 140, thereby providing dual protection against boom overload.

[0054] Based on the above embodiments, alternatively, refer to the following: Figure 3 The oil supply control module 160 includes a proportional directional valve 161 and a proportional valve 162; the boom coupling directional valve 131 also includes a first pilot port and a second pilot port; the first supply port of the proportional directional valve 161 is connected to the first pilot port, the second supply port of the proportional directional valve 161 is connected to the second pilot port, the proportional valve 162 is connected to the proportional directional valve 161, and the proportional valve 162 is used to adjust the proportional directional valve 161 to supply pilot oil to the first pilot port or the second pilot port, so as to adjust the hydraulic pressure of the first pilot port or the second pilot port.

[0055] Figure 3 In this system, the proportional valve 162 can set the pilot pressure for the switching of the boom-connecting directional valve 131. When the right-side solenoid of the proportional valve 161 is energized (i.e., in the right position), pilot oil is delivered through the first delivery port of the proportional valve 161 to the first pilot port of the boom-connecting directional valve 131. As the hydraulic pressure increases, the pilot oil pushes the valve core of the boom-connecting directional valve 131, opening the first port. When the left-side solenoid of the proportional valve 161 is energized (i.e., in the right position), pilot oil is delivered through the second delivery port of the proportional valve 161 to the second pilot port of the boom-connecting directional valve 131. As the hydraulic pressure increases, the pilot oil pushes the valve core of the boom-connecting directional valve 131, opening the second port.

[0056] Based on the above embodiments, alternatively, refer to the following: Figure 3 The hydraulic control module 150 includes a proportional pressure reducing valve 151 and a solenoid switch valve 152. The proportional pressure reducing valve 151 is connected to the solenoid switch valve 152, and the solenoid switch valve 152 is connected to the control port P of each explosion-proof valve 110. Both the proportional pressure reducing valve 151 and the solenoid switch valve 152 are connected to the controller 170. The controller 170 is used to control the hydraulic pressure supplied by the proportional pressure reducing valve 151 to the pilot oil of the solenoid switch valve 152, and the controller 170 is used to control the hydraulic pressure output by the solenoid switch valve 152 to the pilot oil of the control port P.

[0057] During boom descent, the controller 170 controls the proportional pressure reducing valve 151 and the solenoid switch valve 152 to open in a certain proportion, thereby adjusting the pressure at the control port P of the explosion-proof valve 110. This allows oil in the rodless chamber of the cylinder 120 to flow back to the oil delivery module 130 through the oil inlet A of the explosion-proof valve 110. The boom descent speed can be adjusted by the proportional pressure reducing valve 151 and the solenoid switch valve 152. When the opening of the proportional pressure reducing valve 151 and the solenoid switch valve 152 increases, the pressure at the control port P of the explosion-proof valve 110 increases, and the boom descent speed increases. Conversely, when the opening of the proportional pressure reducing valve 151 and the solenoid switch valve 152 decreases, the pressure at the control port P of the explosion-proof valve 110 decreases, and the boom descent speed decreases.

[0058] Based on the above embodiments, alternatively, refer to the following: Figure 3 The boom hydraulic system also includes a pilot pump 180; the hydraulic control module 150 and the oil delivery control module 160 are both connected to the pilot pump 180, and the pilot pump 180 is used to deliver pilot oil to the hydraulic control module 150 or the oil delivery control module 160.

[0059] It should be noted that the pilot oil delivered by the pilot pump 180 is the same as the oil delivered by the oil delivery module 130.

[0060] Based on the above embodiments, alternatively, refer to the following: Figure 3 The boom hydraulic system also includes a pilot filter 190; the pilot filter 190 is connected to the pilot pump 180, and the hydraulic control module 150 and the oil delivery control module 160 are both connected to the pilot filter 190. The pilot filter 190 is used to filter the pilot oil.

[0061] Based on the above embodiments, alternatively, refer to the following: Figure 3 The boom hydraulic system also includes an oil tank 210; each explosion-proof valve 110, oil delivery module 130, hydraulic control module 150 and oil delivery control module 160 are connected to the oil tank 210. The oil tank 210 is used to supply oil to the oil delivery module 130, hydraulic control module 150 and oil delivery control module 160. The oil tank 210 is also used to receive the return oil from the explosion-proof valve 110, oil delivery module 130, hydraulic control module 150 and oil delivery control module 160.

[0062] Based on the above embodiments, alternatively, refer to the following: Figure 3 The boom hydraulic system also includes a check valve 220; the main pump 132 is connected to the boom coupling directional valve 131 through the check valve 220, and the check valve 220 is used to control the oil delivery direction between the main pump 132 and the boom coupling directional valve 131.

[0063] Continue to refer to Figure 3Based on the specific connection relationships described above, the working principles of the following conditions will be further explained: normal boom raising, normal boom lowering, boom holding, boom raising oil inlet line rupture, and boom lowering oil return line rupture.

[0064] 1) The boom rises normally. The boom hydraulic system operates as follows: the pilot pump 180 outputs pilot oil, which is filtered by the pilot filter 190 and then adjusted by the proportional valve 162 to the pilot pressure of the boom directional valve 131. At this time, the electromagnet on the right end of the proportional valve 161 is energized, and the pilot pressure oil is delivered to the first pilot port of the boom directional valve 131 through the first delivery port of the proportional valve 161. As the hydraulic pressure increases, the pilot oil pushes the valve core of the boom directional valve 131 to open the first oil port. The high-pressure oil output by the main pump 132 passes through the first oil port, the inlet A of the boom explosion-proof valve 110, and the outlet C of the boom explosion-proof valve 110 to the rodless chamber of the cylinder 120. The oil in the rod chamber of the cylinder 120 returns through the boom directional valve 131, completing the boom rising action. At this time, the controller 170 does not receive a boom descent signal, so the current of the proportional pressure reducing valve 151 is 0mA and the output pressure is 0MPa. The control port P of the explosion-proof valve 110 has no pressure, and the on / off valve of the explosion-proof valve 110 is not open, so no high-pressure oil passes through. When the boom encounters an excessively high load during ascent, it will cause the pressure in the rodless chamber of the cylinder 120 to increase. If this pressure exceeds the rated working pressure of the cylinder 120, the high-pressure oil will overflow back to the oil tank 210 through the overflow valve of the explosion-proof valve 110. Simultaneously, the hydraulic pressure of the explosion-proof valve 110 is collected by the pressure sensor 141 and transmitted to the controller 170. The controller 170 then issues a corresponding command to control the main pump 132 to reduce its displacement, thus protecting the boom from overload.

[0065] 2) During normal boom descent, the boom hydraulic system operates as follows: Pilot oil output from pilot pump 180 is filtered by pilot filter 190, and then adjusted by proportional valve 162 to the pilot pressure required for the boom coupling directional valve 131 to switch. At this time, the solenoid on the left end of proportional valve 161 is energized, and pilot pressure oil is delivered through the second delivery port of proportional valve 161 to the second pilot port of boom coupling directional valve 131. As the hydraulic pressure increases, the pilot oil pushes the valve core of boom coupling directional valve 131, opening the second port. The high-pressure oil output from main pump 132 then flows through... The oil is supplied to the rod chamber of the hydraulic cylinder 120 through the second oil port. At this time, the controller 170 sends a corresponding boom lowering signal according to the pressure value of the sensor. The proportional pressure reducing valve 151 and the solenoid switch valve 152 are turned on to output the corresponding pilot fluid to the control port P of the explosion-proof valve 110 to adjust the pressure of the control port P of the explosion-proof valve 110, so that the on / off method of the explosion-proof valve 110 is turned on, thereby allowing the high pressure oil in the rodless chamber of the hydraulic cylinder 120 to pass through the on / off valve of the explosion-proof valve 110 to the oil inlet A of the explosion-proof valve 110, and finally return oil through the boom reversing valve 131 to realize the boom lowering. The boom descent speed can be adjusted according to the pressure of the pilot fluid output from the proportional pressure reducing valve 151 and the solenoid switch valve 152. When rapid boom descent is required, the controller 170 increases the output current to the electromagnets of the proportional pressure reducing valve 151 and the solenoid switch valve 152, increasing the opening of the proportional pressure reducing valve 151 and the solenoid switch valve 152, thus increasing the output pilot fluid pressure. This, in turn, increases the opening of the on / off valve of the explosion-proof valve 110, increases the oil return volume in the rodless chamber of the cylinder 120, and increases the boom descent speed. When slow boom descent is required, the controller 170 decreases the output current to the electromagnets of the proportional pressure reducing valve 151 and the solenoid switch valve 152, decreasing the opening of the proportional pressure reducing valve 151 and the solenoid switch valve 152, thus decreasing the output pilot fluid pressure. This, in turn, decreases the opening of the on / off valve of the explosion-proof valve 110, decreases the oil return volume in the rodless chamber of the cylinder 120, and decreases the boom descent speed.

[0066] 3) Boom Holding: The boom hydraulic system operates as follows: After the boom is raised to a certain position, it needs to be fixed in that position and cannot fall automatically. At this time, the explosion-proof valve 110 can function as a load holder. After the boom is raised to a certain position, the electromagnets of the proportional directional valve 161 and the solenoid valve 152 are de-energized, and the proportional directional valve 161 and the solenoid valve 152 are not conducting. At this time, the pilot pressure oil returns directly to the oil tank 210 at a pressure of 0 MPa, and the on / off valve in the explosion-proof valve 110 is not conducting; there is no pilot oil in the first and second pilot ports of the boom-connected directional valve 131, and both the first and second oil ports of the boom-connected directional valve 131 are not conducting. Because the on / off valve and the check valve 220 in the explosion-proof valve 110 are both conical seals, the oil in the rodless chamber of the cylinder 120 cannot leak through the explosion-proof valve 110, thus achieving boom holding. If the load is too large or the cylinder 120 is subjected to severe impact or vibration during the boom holding process, the pressure in the rodless chamber of the cylinder 120 will increase. When the pressure in the rodless chamber of the cylinder 120 exceeds a certain value, the high-pressure oil in the rodless chamber of the cylinder 120 will overflow back to the oil tank 210 through the overflow valve of the explosion-proof valve 110, thereby protecting the boom hydraulic system.

[0067] 4) If the boom lifting oil inlet pipe bursts, the boom hydraulic system will operate as follows: During boom lifting, if the oil inlet pipe suddenly bursts, the electromagnet at the right end of the proportional directional valve 161 will be energized. Pilot pressure oil will be delivered through the first delivery port of the proportional directional valve 161 to the first pilot port of the boom coupling directional valve 131. As the hydraulic pressure increases, the pilot oil will push the valve core of the boom coupling directional valve 131 to open the first oil port. However, at this time, the high-pressure oil of the main pump 132 cannot be delivered to the rodless chamber of the boom cylinder 120 through the pipeline. At the same time, since the on / off valve in the explosion-proof valve 110 is in an unconducted state, the oil in the rodless chamber of the cylinder 120 cannot leak through the explosion-proof valve 110. Therefore, the boom will be quickly locked at the position where the oil inlet pipe burst, preventing the boom from falling rapidly due to the pipeline burst.

[0068] 5) The boom descent return oil line bursts. The boom hydraulic system operates as follows: At the moment the boom descent return oil line bursts, the on / off valve of the explosion-proof valve 110 is activated. Since the pressure at the inlet A of the explosion-proof valve 110 is 0 MPa after the return oil line bursts, the flow rate from the outlet C of the explosion-proof valve 110 to the inlet A will increase sharply. The pressure sensor 141 will detect the sharp increase in pressure and send it to the controller 170. The controller 170 will shut off the proportional pressure reducing valve 151, thereby shutting off the on / off valve of the explosion-proof valve 110, cutting off the return oil line to prevent oil from flowing out and outside air from entering the hydraulic cylinder 120 and damaging the hydraulic system.

[0069] This invention also provides an excavator that includes the boom hydraulic system provided in any embodiment of this invention, which has corresponding beneficial effects, which will not be described in detail here.

[0070] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0071] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A boom hydraulic system, characterized in that, It includes two explosion-proof valves, two hydraulic cylinders, an oil delivery module, a pressure compensation and acquisition module, a hydraulic control module, an oil delivery control module, and a controller; Each of the cylinders has its rodless chamber connected to the outlet of an explosion-proof valve, and each explosion-proof valve has its inlet connected to the first oil delivery path of the oil delivery module. The rod chambers of both cylinders and the return port of the explosion-proof valve are connected to the second oil delivery path of the oil delivery module. The oil delivery control module is connected to the oil delivery module and controls the oil delivery module to connect either the first or second oil delivery path for oil delivery. The hydraulic control module is connected to the control port of the explosion-proof valve and adjusts the pressure at the control port of the explosion-proof valve. The pressure detection ports of the two explosion-proof valves are connected to the pressure compensation and acquisition module, which balances the hydraulic pressure of the two explosion-proof valves and detects the hydraulic pressure of the explosion-proof valves. The oil delivery module, the pressure compensation and acquisition module, and the hydraulic control module are all connected to the controller, which controls the oil delivery volume of the oil delivery module or adjusts the pressure at the control port of the explosion-proof valve based on the hydraulic pressure of the explosion-proof valve. The pressure compensation acquisition module includes a pressure sensor and a pressure compensation hydraulic pipe; Each of the explosion-proof valves has its oil outlet connected to a pressure detection port, and the pressure detection ports of the two explosion-proof valves are connected through the pressure compensation hydraulic pipe, which is used to balance the hydraulic pressure of the two explosion-proof valves. The pressure sensor is connected to the pressure detection port and is used to detect the hydraulic pressure of the explosion-proof valve.

2. The boom hydraulic system according to claim 1, characterized in that, The oil delivery module includes a boom-connected reversing valve and a main pump; The main pump is connected to the oil inlet of the boom reversing valve, the first oil port of the boom reversing valve serves as the first oil delivery path port, and the second oil port of the boom reversing valve serves as the second oil delivery path port. The oil delivery control module is connected to the pilot port of the boom coupling directional valve. The oil delivery control module is used to control the hydraulic pressure of the pilot port of the boom coupling directional valve, thereby controlling the oil delivery through the first or second oil port of the boom coupling directional valve. The controller is connected to the main pump and is used to control the oil delivery rate of the main pump based on the hydraulic pressure of the explosion-proof valve.

3. The boom hydraulic system according to claim 2, characterized in that, The oil delivery control module includes a proportional directional valve and a proportional valve; The boom coupling directional valve also includes a first pilot port and a second pilot port; The first delivery port of the proportional directional valve is connected to the first pilot port, the second delivery port of the proportional directional valve is connected to the second pilot port, the proportional valve is connected to the proportional directional valve, and the proportional valve is used to adjust the proportional directional valve to deliver pilot oil to the first pilot port or the second pilot port, so as to adjust the hydraulic pressure of the first pilot port or the second pilot port.

4. The boom hydraulic system according to claim 1, characterized in that, The hydraulic control module includes a proportional pressure reducing valve and a solenoid switching valve; The proportional pressure reducing valve is connected to the electromagnetic switch valve, and the electromagnetic switch valve is connected to the control port of each of the explosion-proof valves. Both the proportional pressure reducing valve and the electromagnetic switch valve are connected to the controller. The controller is used to control the hydraulic pressure supplied by the proportional pressure reducing valve to the pilot oil of the electromagnetic switch valve, and the controller is used to control the hydraulic pressure output by the electromagnetic switch valve to the pilot oil of the control port.

5. The boom hydraulic system according to claim 1, characterized in that, It also includes a pilot pump; Both the hydraulic control module and the oil delivery control module are connected to the pilot pump, which is used to deliver pilot oil to the hydraulic control module or the oil delivery control module.

6. The boom hydraulic system according to claim 5, characterized in that, It also includes a pilot filter; The pilot filter is connected to the pilot pump, and both the hydraulic control module and the oil delivery control module are connected to the pilot filter. The pilot filter is used to filter the pilot oil.

7. The boom hydraulic system according to claim 1, characterized in that, It also includes the fuel tank; Each of the explosion-proof valves, the oil delivery module, the hydraulic control module, and the oil delivery control module is connected to the oil tank. The oil tank is used to supply oil to the oil delivery module, the hydraulic control module, and the oil delivery control module. The oil tank is also used to receive the return oil from the explosion-proof valves, the oil delivery module, the hydraulic control module, and the oil delivery control module.

8. The boom hydraulic system according to claim 2, characterized in that, It also includes check valves; The main pump is connected to the check valve and the boom directional valve. The check valve is used to control the oil delivery direction between the main pump and the boom directional valve.

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

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