EHA exhaust oil supplement device and exhaust oil supplement method

Abstract

The application provides an EHA exhaust oil supplement device and an exhaust oil supplement method. The device is used for exhausting gas in an EHA system pipeline and supplementing hydraulic oil for an accumulator to reach a pre-charging pressure. When the EHA exhaust oil supplement device is used, the device is installed between a balance valve and an electromagnetic on-off valve of the EHA system through a quick connector, gas in the EHA system pipeline is exhausted by extension and retraction of a cylinder, when the cylinder is fully extended, pressure of an overflow valve in the EHA system and the exhaust oil supplement device is set to zero and oil supply is continued, gas in a pipeline between the overflow valve and an oil tank is exhausted, the accumulator is supplemented with oil through rotation of a pump of the exhaust oil supplement device, and whether oil supplement is completed is monitored through a pressure gauge, the quick connector is disconnected after the oil supplement is completed, the EHA exhaust oil supplement device is taken away, and then the quick connector is connected again, so that the EHA system can be restored to the original state.

Description

Technical Field

[0001] This invention relates to the field of construction machinery, and in particular to the development of an exhaust oil replenishment device for EHA on the boom of construction machinery. Background Technology

[0002] As the number of construction projects gradually increases and the scope and scale of construction expand, the application of construction machinery is becoming more and more widespread, giving it irreplaceable advantages in shortening the construction cycle, improving project quality, and saving costs.

[0003] An electro-hydraulic actuator (EHA) is a high-performance, integrated power actuator that converts input electrical signals into hydraulic pressure to achieve position, speed, direction, and force control. EHAs effectively reduce overflow and throttling losses in hydraulic systems, improve system efficiency, reliability, and maintainability, while also offering advantages such as light weight and ease of integration. Replacing traditional hydraulic systems for engineering machinery booms with EHAs holds great potential. However, during the manufacturing, assembly, and initial startup of EHAs, air may be introduced into the system piping and components, leading to unstable system response, affecting precise control and motion performance. Furthermore, the presence of gas can cause unstable pressure within the system, impacting its efficiency. Therefore, this paper proposes an air venting and oil replenishment device for EHA systems. This device vents gas from the EHA system piping and replenishes hydraulic oil to the accumulator to reach pre-charge pressure, ensuring the hydraulic oil is free of air and maintaining normal system operation and stability. This device has significant engineering value. Summary of the Invention

[0004] To overcome the problems of unstable system response and low operating efficiency caused by gas in the EHA system pipeline, this invention develops an exhaust and oil replenishment device for EHA systems based on the operation and maintenance requirements of EHA systems. This device removes gas from the EHA system pipeline and replenishes hydraulic oil to the accumulator to reach pre-charge pressure.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention first provides an EHA exhaust oil replenishment device, including a quick-connect fitting, a two-position three-way valve, an oil tank, an oil suction filter, a pump, a motor, a first check valve, a second check valve, a pressure gauge, and an overflow valve in the exhaust oil replenishment device;

[0007] There are two 2-position 3-way valves: a first 2-position 3-way valve located on the left and a second 2-position 3-way valve located on the right. Both 2-position 3-way valves are connected to the balance valve and solenoid on / off valve in the EHA system via quick-connect couplings. The hydraulic oil flow path formed by the first 2-position 3-way valve, the balance valve on the left side of the EHA system, and the solenoid on / off valve on the left side of the EHA system is the first pipeline; the hydraulic oil flow path formed by the second 2-position 3-way valve, the balance valve on the right side of the EHA system, and the solenoid on / off valve on the right side of the EHA system is the second pipeline. The two 2-position 3-way valves and the solenoid directional valve work in coordination via electrical signals. When power is supplied to the left side of the solenoid directional valve and the second 2-position 3-way valve, both the solenoid directional valve and the second 2-position 3-way valve are simultaneously in the left position. When power is supplied to the right side of the solenoid directional valve and the first 2-position 3-way valve, the right position of the solenoid directional valve and the left position of the first 2-position 3-way valve are simultaneously in operation.

[0008] In the exhaust oil replenishment device, the pump is connected to the motor and draws hydraulic oil from the oil tank; the inlet of the first check valve is connected to the pump in the exhaust oil replenishment device, and the outlet of the first check valve is connected to the accumulator in the EHA system via a quick-connect coupling; the inlet of the second check valve is connected to the oil tank, and the outlet of the second check valve is connected to the pipeline between the first check valve and the quick-connect coupling; the relief valve and the second check valve in the exhaust oil replenishment device are connected in parallel, and the pressure gauge is installed on the pipeline between the relief valve and the quick-connect coupling.

[0009] The present invention also provides a method for operating the above-mentioned EHA exhaust oil replenishment device, comprising the following steps:

[0010] 1) Connect the exhaust oil replenishment device between the balance valve and the solenoid on / off valve of the EHA system using a quick-connect coupling;

[0011] 2) By extending and retracting the cylinder, the hydraulic oil and gas inside the cylinder are discharged into the oil tank. After repeating this process multiple times, the gas inside the cylinder and the gas in the EHA system pipeline will be completely discharged.

[0012] 3) Extend the cylinder fully and set the pressure of the relief valve in the EHA system and the relief valve in the exhaust oil replenishment device to zero. The pump in the EHA system continues to draw hydraulic oil from the oil tank through the second check valve to provide flow to the cylinder. Since the cylinder is fully extended, the excess hydraulic oil will flow back to the oil tank of the exhaust oil replenishment device through the relief valve in the EHA system and the relief valve in the exhaust oil replenishment device, and the air in the pipeline will be discharged to the oil tank together. After repeated operations, the air in the pipeline between the relief valve and the oil tank in the EHA system will be completely removed.

[0013] 4) After the gas in the pipeline is purged, the accumulator is replenished with oil. The pump in the venting and replenishing device is used to draw hydraulic oil from the oil tank. The hydraulic oil is delivered to the accumulator through the first check valve. The pressure setting of the overflow valve in the venting and replenishing device is changed from zero to the target pressure value of the accumulator. The pressure status is monitored by the pressure gauge. When the pressure gauge reaches the target value, it indicates that the pre-charging and replenishing process of the accumulator is over. At this time, the quick-connect coupling can be disconnected to remove the EHA venting and replenishing device. Connect one end of the EHA system balance valve to one end of the solenoid on / off valve, and the EHA system can operate normally.

[0014] As a preferred embodiment of the present invention, when the cylinder extends in step 2), the EHA system's solenoid directional valve is in the left position. The pump in the EHA system draws hydraulic oil from the oil tank of the exhaust and replenishment device through the second check valve. The hydraulic oil flows out from the left position of the solenoid directional valve, enters the cylinder through the first pipeline, and flows out from the rod chamber of the cylinder. It then flows through the balance valve and the second two-position three-way valve. At this time, when power is supplied to the left side of the solenoid directional valve and the second two-position three-way valve, both the solenoid directional valve and the second two-position three-way valve are simultaneously in the left position. The hydraulic oil enters the oil tank from the left position of the second two-position three-way valve. In the EHA system... When the cylinder retracts, the solenoid directional valve of the EHA system is in the right position. The pump in the EHA system draws hydraulic oil from the oil tank of the exhaust and replenishment device through the second check valve. The hydraulic oil flows out from the right position of the solenoid directional valve, enters the cylinder through the second pipeline, and flows out from the rodless chamber of the cylinder. It then passes through the balance valve and the first two-position three-way valve. At this time, power is supplied to the right side of the solenoid directional valve and the first two-position three-way valve. The right position of the solenoid directional valve and the left position of the first two-position three-way valve work simultaneously. The hydraulic oil flows through the left position of the two-position three-way valve into the oil tank. When the hydraulic oil enters the oil phase, it will also vent the gas in the pipeline to the oil tank.

[0015] As a preferred embodiment of the present invention, after the accumulator is replenished in step 4), the excess hydraulic oil will flow back to the oil tank from the overflow valve to ensure that the pressure in the accumulator no longer rises.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1) This invention is mainly used to realize the function of exhaust and oil replenishment, which can effectively remove gas in the pipeline and replenish hydraulic oil to the accumulator to reach the pre-charge pressure, thus maintaining the stability and working efficiency of the EHA system.

[0018] 2) This invention uses a quick-connect coupling. When disconnected, the pipeline is sealed off, which will not affect the operation of the EHA system. After the coupling is inserted, the two check valves inside the quick-connect coupling open, allowing hydraulic oil to flow, which facilitates the installation and disassembly of the exhaust and oil replenishment device. The operation is simple and efficient.

[0019] 3) This invention enables the use of a suction filter to filter impurities in hydraulic oil, ensuring the quality of hydraulic oil, maintaining the normal operation of the EHA system, and extending the service life of the EHA system. Attached Figure Description

[0020] Figure 1 Schematic diagram of EHA exhaust fuel replenishment device

[0021] In the diagram, 1-Quick connector, 2-Two-position three-way valve, 3-Oil tank, 4-Suction filter, 5-Pump in exhaust oil replenishment device, 6-Motor, 7-First check valve, 8-Second check valve, 9-Pressure gauge, 10-Relief valve in exhaust oil replenishment device, 11-Balance valve, 12-Solenoid on / off valve, 13-Accumulator, 14-Relief valve in EHA system, 15-Solenoid directional valve, 16-Pump in EHA system.

[0022] Figure 2 Workflow diagram for EHA exhaust oil replenishment device Detailed Implementation

[0023] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0024] like Figure 1 As shown, an EHA exhaust oil replenishment device includes a quick-connect coupling 1, a two-position three-way valve 2, an oil tank 3, an oil suction filter 4, a pump 5, a motor 6, a first check valve 7, a second check valve 8, a pressure gauge 9, and an overflow valve 10. The EHA exhaust oil replenishment device is mainly used to exhaust gas from the EHA system pipeline and replenish hydraulic oil to the accumulator to reach the pre-charge pressure. The EHA exhaust oil replenishment device is connected to the EHA system via the quick-connect coupling 1. There are two two-position three-way valves 2: a first two-position three-way valve on the left and a second two-position three-way valve on the right, both connected to the EHA system via the quick-connect coupling 1. Valve 11 is connected to solenoid on / off valve 12; the hydraulic oil flow path formed by the first two-position three-way valve, the balance valve 11, and the solenoid on / off valve 12 in the EHA system is the first pipeline; the hydraulic oil flow path formed by the second two-position three-way valve, the balance valve 11, and the solenoid on / off valve 12 in the EHA system is the second pipeline; the two two-position three-way valves and the solenoid directional valve work in coordination via electrical signals. When power is supplied to the left side of the solenoid directional valve and the second two-position three-way valve, both the solenoid directional valve and the second two-position three-way valve are simultaneously in the left position; when power is supplied to the right side of the solenoid directional valve and the first two-position three-way valve, the right position of the solenoid directional valve and the left position of the first two-position three-way valve are simultaneously in operation.

[0025] In the exhaust oil replenishment device, pump 5 is connected to motor 6 and draws hydraulic oil from oil tank 3; the inlet of the first check valve 7 is connected to pump 5 in the exhaust oil replenishment device, and the outlet of the first check valve is connected to accumulator 13 in the EHA system through quick connector 1; the inlet of the second check valve 8 is connected to oil tank 3, and the outlet of the second check valve is connected to the pipeline between the first check valve and quick connector 1; the overflow valve 10 in the exhaust oil replenishment device is connected in parallel with the second check valve 8, and the pressure gauge 9 is installed on the pipeline between the overflow valve 10 and quick connector 1.

[0026] In the EHA system, pump 16 draws hydraulic oil from tank 3 in the exhaust oil replenishment device through the second check valve 7. The hydraulic oil enters the cylinder through solenoid directional valve 15, solenoid on / off valve 12, two-position three-way valve 2, and balance valve 11. After flowing out of the cylinder, it flows back to the tank through the balance valve and the two-position three-way valve. In the exhaust oil replenishment device, pump 5 is connected to motor 6 and draws hydraulic oil from the tank through suction filter 4, flowing to the accumulator through the first check valve and pressure gauge. When the EHA exhaust oil replenishment device is in use, the extension and retraction of the cylinder discharges the gas in the pipeline. After ten repetitions, the gas in the cylinder and the EHA system pipeline is completely discharged. Then, when the cylinder is fully extended, the pressure of the overflow valve in the EHA system and the overflow valve 10 in the exhaust oil replenishment device are both set to zero and oil supply continues, thus purging the gas in the pipeline between the EHA system overflow valve and the tank.

[0027] In a specific embodiment of the present invention, the accumulator pressure is set to 2 bar. After the exhaust process is completed, the pump 5 in the exhaust oil replenishment device rotates to replenish the accumulator. The pressure setting of the overflow valve 10 in the exhaust oil replenishment device is changed from zero to 2 bar, and the pressure status is monitored by a pressure gauge. When it reaches 2 bar, it indicates that the accumulator oil replenishment process is completed. After completion, the quick-connect connector is disconnected and the EHA exhaust oil replenishment device is removed. The quick-connect connector at one end of the EHA system balance valve is reconnected to the quick-connect connector at one end of the solenoid on / off valve, and the EHA system can then operate normally.

[0028] In one specific embodiment of the present invention, the quick-connect fitting connects the exhaust oil replenishment device to the EHA system. After the fitting is inserted, the two check valves inside the quick-connect fitting open, allowing hydraulic oil to flow and ensuring the normal operation of the EHA system and the exhaust oil replenishment device. After the plug is disconnected, the pipeline is sealed. At this time, the exhaust oil replenishment device is removed, and the quick-connect fitting at one end of the EHA system balance valve is reconnected to the quick-connect fitting at one end of the solenoid on / off valve, and the EHA system can operate normally.

[0029] In one specific embodiment of the present invention, the suction filter is used to filter impurities in the hydraulic oil, ensure the quality of the hydraulic oil, maintain the normal operation of the EHA system, and extend the service life of the EHA system.

[0030] In one specific embodiment of the present invention, the pressure gauge is used to monitor the accumulator replenishment pressure and determine whether the accumulator pre-charging is complete.

[0031] To more clearly illustrate the working process of the above-mentioned device, this embodiment also provides a method for using the above-mentioned EHA exhaust oil replenishment device, including the following steps:

[0032] 1) Connect the two quick-connect fittings of the first two-position three-way valve to the fittings of the balance valve 11 on the left side of the EHA system and the solenoid on / off valve 12 on the left side of the EHA system, respectively; connect the two quick-connect fittings of the second two-position three-way valve to the fittings of the balance valve 11 on the right side of the EHA system and the solenoid on / off valve 12 on the right side of the EHA system, respectively; connect the quick-connect fitting at the output port of the first check valve to the fitting of the accumulator 13 in the EHA system, thereby connecting the exhaust oil replenishment device between the balance valve and the solenoid on / off valve of the EHA system.

[0033] 2) The hydraulic oil and gas inside the cylinder are discharged into the oil tank by extending and retracting the cylinder. When the cylinder extends, the EHA system's solenoid directional valve is in the left position. The pump in the EHA system draws hydraulic oil from the oil tank of the exhaust and replenishment device through the second check valve. The hydraulic oil flows out from the left position of the solenoid directional valve, enters the cylinder through the first pipeline, and flows out from the rod chamber of the cylinder. It then flows through the balance valve and the second 2-position 3-way valve. At this time, when power is supplied to the left side of the solenoid directional valve and the second 2-position 3-way valve, both the solenoid directional valve and the second 2-position 3-way valve are simultaneously in the left position, and the hydraulic oil enters the oil tank from the left position of the second 2-position 3-way valve. When the EHA system's cylinder retracts, the EHA system's solenoid directional valve is in the right position. In the EHA system, the pump draws hydraulic oil from the tank of the exhaust and replenishment device through the second check valve. The hydraulic oil flows out from the right position of the solenoid directional valve, enters the cylinder through the second pipeline, and flows out from the rodless chamber of the cylinder. It then passes through the balance valve and the first two-position three-way valve. At this time, power is supplied to the right side of the solenoid directional valve and the first two-position three-way valve. The right position of the solenoid directional valve and the left position of the first two-position three-way valve work simultaneously. The hydraulic oil flows through the left position of the two-position three-way valve into the oil tank. When the hydraulic oil enters the oil phase, it will also vent the gas in the pipeline to the oil tank. After ten cycles, the gas in the cylinder and the pipeline of the EHA system will be completely vented.

[0034] 3) When the cylinder is fully extended, adjust the pressure of the relief valves in both the EHA system and the venting and replenishing device to zero. The EHA system continues to draw hydraulic oil from the tank through the second check valve to provide flow to the cylinder. Since the cylinder is fully extended, excess hydraulic oil will flow back to the tank of the venting and replenishing device through the relief valves in the EHA system and the venting and replenishing device. The air in the pipeline will be discharged into the tank along with the hydraulic oil. After ten reciprocating operations, the air in the pipeline between the relief valve and the tank in the EHA system will be completely removed.

[0035] 4) After the gas in the pipeline is purged, replenish the accumulator with oil. Use the pump in the purging and replenishing device to transfer the hydraulic oil in the tank to the accumulator through the first check valve. Change the pressure setting of the overflow valve in the purging and replenishing device from zero to the target pressure value of the accumulator and monitor the pressure status with a pressure gauge. When the pressure gauge reaches the target value, it means that the pre-charging and replenishing process of the accumulator is over. The excess hydraulic oil will flow back to the tank through the overflow valve to ensure that the pressure in the accumulator does not rise. At this time, disconnect the quick-connect coupling to remove the EHA purging and replenishing device. Reconnect one end of the EHA system balance valve to the other end of the solenoid on / off valve, and the EHA system can operate normally.

[0036] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An EHA exhaust oil supplement device characterized by, The EHA exhaust oil supplement device comprises a quick connector (1), a two-position three-way valve (2), an oil tank (3), an oil suction filter (4), a pump (5) in the exhaust oil supplement device, a motor (6), a first one-way valve (7), a second one-way valve (8), a pressure gauge (9), and an overflow valve (10) in the exhaust oil supplement device. The two-position three-way valve (2) is two valves, one of which is a first two-position three-way valve on the left side and the other of which is a second two-position three-way valve on the right side. One oil port of the first two-position three-way valve is connected to the oil tank (3), and one oil port of the second two-position three-way valve is connected to the oil tank (3). Both of the two-position three-way valves (2) are connected to the balance valve (11) and the electromagnetic on-off valve (12) in the EHA system through the quick connector (1). The hydraulic oil flow formed by the first two-position three-way valve, the balance valve (11) on the left side of the EHA system, and the electromagnetic on-off valve (12) on the left side of the EHA system is the first pipeline. The hydraulic oil flow formed by the second two-position three-way valve, the balance valve (11) on the right side of the EHA system, and the electromagnetic on-off valve (12) on the right side of the EHA system is the second pipeline. The two two-position three-way valves and the electromagnetic reversing valve work cooperatively through electrical signals. When the left side of the electromagnetic reversing valve and the second two-position three-way valve are powered, the electromagnetic reversing valve and the second two-position three-way valve work simultaneously in the left position. When the right side of the electromagnetic reversing valve and the first two-position three-way valve are powered, the right side of the electromagnetic reversing valve and the left side of the first two-position three-way valve work simultaneously. The pump (5) in the exhaust oil supplement device is connected to the motor (6) and sucks hydraulic oil from the oil tank (3). The input port of the first one-way valve (7) is connected to the pump (5) in the exhaust oil supplement device, and the output port of the first one-way valve is connected to the accumulator (13) in the EHA system through the quick connector (1). The input port of the second one-way valve (8) is connected to the oil tank (3), and the output port of the second one-way valve is connected to the pipeline between the first one-way valve and the quick connector (1). The overflow valve (10) in the exhaust oil supplement device is connected in parallel with the second one-way valve (8), and the pressure gauge (9) is arranged on the pipeline between the overflow valve (10) and the quick connector (1).

2. The EHA vent oil supplement device of claim 1, wherein, The EHA exhaust oil supplement device has five quick connectors (1), two of which are connected to the connectors at one end of the balance valve (11) in the EHA system, two of which are connected to the connectors at one end of the electromagnetic on-off valve (12) in the EHA system, and one of which is connected to the connector at one end of the accumulator (13) in the EHA system. The five quick connectors together connect the exhaust oil supplement device to the EHA system. After the quick connector (1) is inserted, the two one-way valves inside the quick connector open to allow the flow of hydraulic oil, ensuring the normal operation of the EHA system and the exhaust oil supplement device. After the quick connector (1) is disconnected, the pipeline is sealed, and at this time, the exhaust oil supplement device is removed, the connector at one end of the balance valve (11) in the EHA system is connected to the connector at one end of the electromagnetic on-off valve (12), and the EHA system can operate normally.

3. The EHA vent oiler of claim 2, wherein, The connectors at one end of the balance valve (11), the electromagnetic on-off valve (12), and the accumulator (13) in the EHA system are all quick connectors.

4. The EHA vent oiler of claim 1, wherein, The oil absorption filter is used for filtering impurities in hydraulic oil, ensuring the quality of the hydraulic oil, maintaining the normal operation of the EHA system, and prolonging the service life of the EHA system.

5. The EHA vent oiler of claim 1, wherein, The first one-way valve is used to ensure that the hydraulic oil can only flow out of the pump (5) in the exhaust oil supplementing device and cannot flow back in the reverse direction, thereby preventing the pump (5) in the exhaust oil supplementing device from being reversed; and the second one-way valve is used to supply oil to the pump in the EHA system, so that the oil in the oil tank can flow back to the oil suction port of the pump in the EHA system smoothly.

6. The EHA vent oiler of claim 1, wherein, The pressure gauge is used to monitor the accumulator oil supplementing pressure and judge whether the accumulator pre-charging is completed.

7. An exhaust oil supplementing method for the exhaust oil supplementing device according to claim 1, characterized by, The method comprises the following steps: 1) connecting the exhaust oil supplementing device to the balance valve and the electromagnetic on-off valve in the EHA system by using quick connectors; 2) discharging the hydraulic oil and gas in the oil cylinder to the oil tank by extending and retracting the oil cylinder, and after repeated operations, the gas in the oil cylinder and the gas in the pipeline of the EHA system are completely discharged; 3) completely extending the oil cylinder, setting the pressure of the overflow valve in the EHA system and the overflow valve in the exhaust oil supplementing device to zero, and continuing to supply the oil tank with hydraulic oil by the pump in the EHA system through the second one-way valve; since the oil cylinder has been completely extended, the excess hydraulic oil will flow back to the oil tank in the exhaust oil supplementing device through the overflow valve in the EHA system and the overflow valve in the exhaust oil supplementing device, and the gas in the pipeline will be discharged to the oil tank; after repeated operations, the gas in the overflow valve in the EHA system and the pipeline between the oil tank is completely discharged; 4) after the gas in the pipeline is completely discharged, the accumulator is supplemented with oil, the pump (5) in the exhaust oil supplementing device is rotated to suck the hydraulic oil in the oil tank, the hydraulic oil is transported to the accumulator through the first one-way valve, the pressure of the overflow valve (10) in the exhaust oil supplementing device is set from zero to the target pressure value of the accumulator, and the pressure state is monitored by the pressure gauge; when the pressure gauge reaches the target value, it indicates that the pre-charging and oil supplementing process of the accumulator is completed, at this time, the quick connector is disconnected, the EHA exhaust oil supplementing device is removed, the balance valve end of the EHA system is connected to the electromagnetic on-off valve end, and the EHA system can operate normally.

8. The exhaust gas oil supplementing method of the EHA exhaust gas oil supplementing device according to claim 7, characterized by, The step 1) is specifically: connecting the two quick connectors of the first two-position three-way valve to the connector of the balance valve (11) on the left side of the EHA system and the connector of the electromagnetic on-off valve (12) on the left side of the EHA system respectively; connecting the two quick connectors of the second two-position three-way valve to the connector of the balance valve (11) on the right side of the EHA system and the connector of the electromagnetic on-off valve (12) on the right side of the EHA system respectively; and connecting the quick connector at the output port of the first one-way valve to the connector of the accumulator (13) in the EHA system, so as to connect the exhaust oil supplementing device to the balance valve and the electromagnetic on-off valve in the EHA system.

9. The exhaust gas oil supplementing method of the EHA exhaust gas oil supplementing device according to claim 7, characterized by, When the oil cylinder extends in the step 2), the electromagnetic reversing valve of the EHA system is in the left position, the pump in the EHA system sucks hydraulic oil from the oil tank of the exhaust oil supplement device through the second one-way valve, the hydraulic oil flows out from the left position of the electromagnetic reversing valve, enters the oil cylinder through the first pipeline, flows out from the rod cavity of the oil cylinder, passes through the balance valve and the second two-position three-way valve, and when the left side of the electromagnetic reversing valve and the second two-position three-way valve are powered, the electromagnetic reversing valve and the second two-position three-way valve work in the left position at the same time, and the hydraulic oil enters the oil tank from the left position of the second two-position three-way valve; when the oil cylinder retracts in the EHA system, the electromagnetic reversing valve of the EHA system is in the right position, the pump in the EHA system sucks hydraulic oil from the oil tank of the exhaust oil supplement device through the second one-way valve, the hydraulic oil flows out from the right position of the electromagnetic reversing valve, the hydraulic oil enters the oil cylinder through the second pipeline, flows out from the rodless cavity of the oil cylinder, passes through the balance valve and the first two-position three-way valve, and when the right side of the electromagnetic reversing valve and the first two-position three-way valve are powered, the right side of the electromagnetic reversing valve and the left side of the first two-position three-way valve work at the same time, and the hydraulic oil flows into the oil tank through the left side of the two-position three-way valve; when the hydraulic oil enters the oil tank, the gas in the pipeline is discharged into the oil tank.

10. The exhaust gas oil supplementing method of the EHA exhaust gas oil supplementing device according to claim 7, characterized by, After the accumulator oil supplement ends in the step 4), the excess hydraulic oil will flow back to the oil tank from the overflow valve, so that the pressure in the accumulator does not rise again.

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