Hydraulic system with adaptive cushioning under impact

Abstract

The application discloses a hydraulic system and hydraulic equipment with self-adaptive buffering under impact, which comprises a hydraulic motor for driving an executing element, a closed pump set for driving the hydraulic motor, a first oil path for connecting an oil outlet of the closed pump set with an oil inlet of the hydraulic motor, a second oil path for connecting an oil outlet of the hydraulic motor with an oil inlet of the closed pump set, and a self-adaptive buffering valve set for weakening pressure impact of a high-pressure side oil path and avoiding pressure suction of a low-pressure side oil path, wherein the oil inlets and outlets of the two self-adaptive buffering valve sets are oppositely connected with the first oil path and the second oil path in parallel. The self-adaptive buffering valve set can weaken the pressure impact of the high-pressure side oil path, and simultaneously avoid the rapid reduction of the low-pressure side pressure or even the suction, so as to ensure the normal work of the hydraulic closed system and prolong the service life of the hydraulic closed system and each element.

Description

Technical Field

[0001] This invention relates to the field of hydraulic equipment technology, and in particular, to a hydraulic system with adaptive cushioning under impact. Furthermore, this invention also relates to a hydraulic device comprising the aforementioned hydraulic system with adaptive cushioning under impact. Background Technology

[0002] The hydraulic closed-loop drive systems of engineering machinery such as tunnel boring machine cutterheads, screw conveyors, and chain cutter continuous wall equipment, mining machinery such as tunneling and anchoring machines, agricultural machinery such as cotton harvesters, and special machinery such as snow blowers are subject to severe pressure shocks on the high-pressure side of the system during operation due to sudden load changes, machine jamming, and start-up conditions. At the same time, the low-pressure side is also affected by the shocks, resulting in pressure reduction and cavitation. This causes damage to the internal plunger structure of the closed-loop pump and motor, thus affecting its service life.

[0003] Currently, the main solution for buffering hydraulic system impacts is to incorporate a relief valve or accumulator into the system pressure impact oil circuit. Because hydraulic shocks are instantaneous and rapid, conventional relief valves cannot respond in time, resulting in relief pressure control failure or significant pressure overshoot. Soft relief valves can achieve a low-pressure starting point response at the moment of impact pressure, thus greatly reducing pressure overshoot. However, they only work for impacts with pressures higher than the spring set value and cannot overflow according to the corresponding changes in pressure impacts of different amplitudes. Furthermore, once their structural parameters are determined, the pressure rise slope is a fixed value and cannot be adjusted. Accumulators are commonly used shock-absorbing elements in hydraulic systems. When connected in parallel with the impact oil circuit, the high-pressure nitrogen in the accumulator reaches a balance with the oil pressure, utilizing the free contraction and expansion characteristics of nitrogen to achieve a "peak shaving and valley smoothing" effect. However, in a closed hydraulic system, the oil volume on the high-pressure side and the low-pressure side are in dynamic equilibrium. Adding an accumulator means a significant increase in the total volume of the high-pressure side oil and a significant decrease in the system's elastic modulus. This causes a significant increase in the required replenishment flow rate during the impact, making the low-pressure side pressure prone to cavitation due to insufficient replenishment flow, severely affecting the service life of the system's closed pumps and motors. Summary of the Invention

[0004] This invention provides an adaptive buffer hydraulic system and hydraulic equipment under impact to solve the technical problem that existing hydraulic systems suffer from severe pressure shock on the high-pressure side of the oil circuit, while the low-pressure side is also affected by the impact, resulting in pressure reduction and cavitation, which easily damages the internal piston structure of closed pumps and motors.

[0005] According to one aspect of the present invention, a hydraulic system for adaptive buffering under impact is provided, comprising a hydraulic motor for driving an actuator, a closed-loop pump assembly for driving the hydraulic motor, a first oil passage for connecting the outlet of the closed-loop pump assembly to the inlet of the hydraulic motor, a second oil passage for connecting the outlet of the hydraulic motor to the inlet of the closed-loop pump assembly, and an adaptive buffer valve assembly for weakening the pressure impact on the high-pressure side oil passage and preventing the pressure from being sucked into the low-pressure side oil passage, wherein the inlets and outlets of the two adaptive buffer valve assemblies are connected in parallel with the first oil passage and the second oil passage, respectively.

[0006] Further, the adaptive buffer valve assembly includes a pilot relief valve, a first damper, a check valve, an accumulator, a second damper, and a main valve core. The outlet of the pilot relief valve is connected to the outlet of the main valve core. The inlet of the pilot relief valve, the outlet of the first damper, the inlet of the check valve, the accumulator, the outlet of the second damper, and the first external control port of the main valve core are connected. The first external control port of the main valve core is located on the same side as a spring used to keep the main valve core normally closed. The oil inlet of the first damper, the oil outlet of the one-way valve, the oil inlet of the second damper, the oil inlet of the main valve core, and the second external control port of the main valve core are connected. The oil inlet of the main valve core of one adaptive buffer valve group is connected to the oil outlet of the closed pump group, and the oil outlet of the main valve core is connected to the oil inlet of the closed pump group. The oil outlet of the main valve core of another adaptive buffer valve group is connected to the oil outlet of the closed pump group, and the oil inlet of the main valve core is connected to the oil inlet of the closed pump group.

[0007] Furthermore, the adaptive buffer valve group includes a solenoid directional valve, and multiple accumulators corresponding to different pressures are connected to the first external control port of the main valve core after being switched by the solenoid directional valve.

[0008] Furthermore, the closed-loop pump assembly includes a closed-loop pump and a first motor for driving the closed-loop pump.

[0009] Furthermore, it also includes a replenishing pump assembly, which includes a replenishing pump connected to the first oil circuit and the second oil circuit, a second motor for driving the replenishing pump, and a replenishing overflow valve for adjusting the replenishing pressure.

[0010] Furthermore, the closed-loop pump unit also includes a replenishing check valve, with two replenishing check valves respectively installed on the replenishing oil lines of the first oil line and the second oil line connected to the replenishing pump.

[0011] Furthermore, it also includes a flushing valve assembly for allowing a portion of the oil from the lower-pressure side of the first and second oil passages to flow back to the oil tank.

[0012] Furthermore, the flushing valve assembly includes a flushing shuttle valve and a flushing overflow valve. The two oil inlets of the flushing shuttle valve are respectively connected to the first oil circuit and the second oil circuit, and the oil outlet of the flushing shuttle valve is connected to the oil tank through the flushing overflow valve.

[0013] Furthermore, the closed-loop pump unit also includes flushing damping for controlling the flow rate of flushing the closed-loop pump bearings and housing.

[0014] According to another aspect of the invention, a hydraulic device is also provided, which includes the aforementioned hydraulic system for adaptive shock absorption.

[0015] The present invention has the following beneficial effects:

[0016] The hydraulic system for adaptive buffering under impact of the present invention comprises a closed-loop pump group, a hydraulic motor, a first oil circuit, and a second oil circuit, forming a closed-loop hydraulic system. During operation, only one side of the first and second oil circuits is a high-pressure oil circuit, and the other side is a low-pressure oil circuit. Therefore, only one set of adaptive buffer valve group 1a and adaptive buffer valve group 1b connected to the high-pressure side at the inlet is active, while the other set connected to the high-pressure side at the outlet is always closed. Its ingenious structure ensures that regardless of whether the hydraulic motor rotates forward or backward, there is always one set of adaptive buffer valve group that weakens the pressure impact on the high-pressure side oil circuit, while preventing the low-pressure side pressure from rapidly decreasing or even cavitating, thus ensuring the normal operation of the closed-loop hydraulic system and extending the service life of the closed-loop hydraulic system and its components.

[0017] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 This is a schematic diagram of the hydraulic system for adaptive buffering under impact according to a preferred embodiment of the present invention;

[0020] Figure 2 This is the second schematic diagram of the adaptive buffer valve assembly of the preferred embodiment of the present invention;

[0021] Figure 3 This is one of the schematic diagrams of the adaptive buffer valve assembly of a preferred embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of a closed-loop pump unit according to a preferred embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the flushing valve assembly according to a preferred embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the oil replenishment pump assembly according to a preferred embodiment of the present invention;

[0025] Figure 7 This is a comparison curve of the high and low pressure sides of the hydraulic closed system under impact conditions between the preferred embodiment of the present invention and the prior art.

[0026] Figure 8 This is a comparison curve of the high and low pressure sides of the hydraulic closed system under the working conditions of a chuck, between the preferred embodiment of the present invention and the prior art.

[0027] Figure 9 This is a comparison curve of the high and low pressure sides of the hydraulic closed system under startup conditions between the preferred embodiment of the present invention and the prior art.

[0028] Legend:

[0029] 1. Adaptive buffer valve assembly; 11. Pilot relief valve; 12. First damper; 13. Check valve; 14. Accumulator; 15. Second damper; 16. Main valve core; 17. Low-pressure accumulator; 18. High-pressure accumulator; 19. Solenoid directional valve; 2. Closed-loop pump assembly; 21. First motor; 22. Closed-loop pump; 23. Make-up check valve; 24. Flushing damper; 3. Flushing valve assembly; 31. Flushing shuttle valve; 32. Flushing relief valve; 4. Hydraulic motor; 5. Make-up pump assembly; 51. Second motor; 52. Make-up pump; 53. Make-up relief valve; 6. First oil circuit; 7. Second oil circuit. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0031] like Figure 1 As shown, the hydraulic system for adaptive buffering under impact in this embodiment includes a hydraulic motor 4 for driving the actuator, a closed pump group 2 for driving the hydraulic motor 4, a first oil passage 6 for connecting the oil outlet of the closed pump group 2 and the oil inlet of the hydraulic motor 4, a second oil passage 7 for connecting the oil outlet of the hydraulic motor 4 and the oil inlet of the closed pump group 2, and an adaptive buffer valve group 1 for weakening the pressure impact of the high-pressure side oil passage and preventing the low-pressure side oil passage from sucking in air. The oil inlets and outlets of the two adaptive buffer valve groups 1 are connected in parallel with the first oil passage 6 and the second oil passage 7, respectively.

[0032] The adaptive buffer hydraulic system for impact protection in this embodiment consists of a closed-loop pump group 2, a hydraulic motor 4, a first oil circuit 6, and a second oil circuit 7. During operation, only one side of the first oil circuit 6 and the second oil circuit 7 is a high-pressure oil circuit, while the other side is a low-pressure oil circuit. Therefore, only one set of adaptive buffer valve groups 1a and 1b, whose inlet is connected to the high-pressure side, is active, while the other set, whose outlet is connected to the high-pressure side, remains closed. Its ingenious structure ensures that regardless of whether the hydraulic motor 4 rotates forward or backward, there is always one set of adaptive buffer valve group 1 that can weaken the pressure impact on the high-pressure side oil circuit, while preventing the low-pressure side pressure from dropping rapidly or even cavitation. This ensures the normal operation of the hydraulic closed-loop system and extends the service life of the hydraulic closed-loop system and its components.

[0033] like Figure 1 , Figure 2 and Figure 7As shown, in this embodiment, the adaptive buffer valve assembly 1 includes a pilot relief valve 11, a first damper 12, a one-way valve 13, an accumulator 14, a second damper 15, and a main valve core 16. The oil outlet of the pilot relief valve 11 is connected to the oil outlet of the main valve core 16. The oil inlet of the pilot relief valve 11, the oil outlet of the first damper 12, the oil inlet of the one-way valve 13, the oil outlet of the accumulator 14, the oil outlet of the second damper 15, and the first external control port of the main valve core 16 are connected. The first external control port of the main valve core 16 is connected to a valve for maintaining the main valve core 16 normally closed. Springs are arranged on the same side. The oil inlet of the first damper 12, the oil outlet of the one-way valve 13, the oil inlet of the second damper 15, the oil inlet of the main valve core 16, and the second external control port of the main valve core 16 are connected. The oil inlet of the main valve core 16 of one adaptive buffer valve group 1 is connected to the oil outlet of the closed pump group 2, and the oil outlet of the main valve core 16 is connected to the oil inlet of the closed pump group 2. The oil outlet of the main valve core 16 of another adaptive buffer valve group 1 is connected to the oil outlet of the closed pump group 2, and the oil inlet of the main valve core 16 is connected to the oil inlet of the closed pump group 2.Taking the second oil circuit 7 as the high-pressure side oil circuit as an example, and the first oil circuit 6 as the low-pressure side oil circuit, at this time, the adaptive buffer valve group 1a connected to the inlet of the second oil circuit 7 is active, and the adaptive buffer valve group 1b connected to the inlet of the first oil circuit 6 is not active; the spring side of the main valve core 16 is defined as the right side, and the opposite side of the spring is defined as the left side. The oil inlet of the main valve core 16 is at the bottom, and the oil outlet of the main valve core 16 is at the top; when the hydraulic closed system encounters an impact condition during operation, the pressure of the high-pressure side oil circuit rises rapidly under a single impact. At this time, the pressure on the left side of the main valve core 16 rises rapidly, and the pressure oil flows into the accumulator 14 through the first damper 12 and the second damper 15. The pilot relief valve 11 is set to the system safety protection pressure. When the pressure of the accumulator 14 does not reach the required level... When the safety protection pressure is reached, the pilot relief valve 11 does not open. Due to the flow restriction effect of the first damper 12 and the second damper 15, and the buffering effect of the accumulator 14's own volume, the pressure rise rate of the first external control port on the right side of the main valve core 16, which is directly connected to the accumulator 14, is lower than the pressure rise rate of the second external control port on the left side of the main valve core 16. The spring pressure value on the right side of the main valve core 16 is much smaller than the impact working pressure. Therefore, the pressure of the second external control port on the left side of the main valve core 16 is greater than the sum of the pressure of the first external control port on the right side and the spring pressure value. The main valve core 16 opens, allowing part of the oil in the high-pressure side oil circuit (second oil circuit 7) to flow to the low-pressure side oil circuit (first oil circuit 6). The pressure shock of the high-pressure side oil circuit is greatly weakened, avoiding the closed pump unit 2 from being subjected to frequent... Under repeated impact conditions, damage is prevented, thus ensuring service life. As each impact continues, the accumulator 14 is continuously charged with oil, and the pressure of the accumulator 14 gradually increases to be the same as the pressure on the left side of the main valve core 16. The pressure at the second external control port on the left side of the main valve core 16 gradually becomes less than the sum of the spring pressure on the right side of the main valve core 16 and the pressure at the first external control port. The main valve core 16 gradually closes to prevent prolonged overflow from causing system overheating and energy waste. The slope of the gradual closing of the main valve core 16 can be changed by adjusting the size of the first damper 12, the volume of the accumulator 14, and the nitrogen charging pressure, thereby making the slope of the pressure reduction effect on the high-pressure side oil circuit adjustable. After the single impact ends, the pressure in the high-pressure side oil circuit drops, and the accumulator 14... The high-pressure oil in section 4 flows back to the high-pressure side through check valve 13 to ensure that the pressure on the left side of the main valve core 16 is equal to the pressure at the right external control port during the non-impact stage, ensuring normal operation before the next impact begins. In addition, when the pressure in the high-pressure side oil circuit continues to rise to the set pressure of the pilot relief valve 11, the pressurized oil flows into the low-pressure side through the second damper 15 and the pilot relief valve 11. A pressure difference is formed before and after the second damper 15, making the pressure at the second external control port on the left side of the main valve core 16 greater than the sum of the spring pressure on the right side and the pressure at the first external control port. The main valve core 16 opens, allowing some oil from the high-pressure side oil circuit to flow into the low-pressure side oil circuit. Through the spring-adjustable mechanism of the pilot relief valve 11, the maximum limit on the pressure of the high-pressure side oil circuit is achieved, protecting the high-pressure side pressure of the system from exceeding the safe set value.

[0034] like Figure 3As shown, in this embodiment, the adaptive buffer valve group 1 includes a solenoid directional valve 19. Multiple accumulators 14 corresponding to different pressures are connected to the first external control port of the main valve core 16 by switching the working circuit of the solenoid directional valve 19. The accumulators 14 include a low-pressure accumulator 17 and a high-pressure accumulator 18. Because the nitrogen charging pressure P0 must satisfy 0.9P1≤P0≤0.25P1 with respect to the maximum working pressure P2 and the minimum working pressure P1, the accumulator is used when the impact is severe and the impact is most intense. When the pressure is high, the solenoid directional valve 19 can be energized, connecting the high-pressure accumulator 18 to the external control port on the right side of the main valve core 16. The nitrogen charging pressure in the high-pressure accumulator 18 is higher than that in the low-pressure accumulator 17. By switching the working circuit of the solenoid directional valve 19, different accumulators with different nitrogen charging pressures can be connected under different pressure impact amplitude conditions, preventing the low-pressure accumulator 17 from being over-compressed under high pressure. It can be understood that the accumulator 14 can be further subdivided into different pressure levels according to the working conditions of the hydraulic closed system.

[0035] like Figure 1 and Figure 4 As shown, in this embodiment, the closed-loop pump group 2 includes a closed-loop pump 22 and a first motor 21 for driving the closed-loop pump 22. The closed-loop pump group 2 can change the speed and direction of the hydraulic motor 4 by adjusting the displacement and direction of the closed-loop pump 22. When the hydraulic closed-loop system starts working, the first motor 21 is started, and the first motor 21 drives the closed-loop pump 22 to rotate. By increasing the displacement of the closed-loop pump 22, the hydraulic motor 4 rotates and drives the working device to operate. At this time, the oil inflow side of the hydraulic motor 4 is the high-pressure side oil circuit due to the load, and the oil outflow side is the low-pressure side oil circuit. Optionally, the output flow rate and oil supply direction of the closed-loop pump 22 can be adjusted by the first motor 21 to change the speed and direction of the hydraulic motor 4.

[0036] like Figure 1 and Figure 6 As shown, this embodiment also includes a replenishing pump assembly 5. The replenishing pump assembly 5 includes a replenishing pump 52 connected to the first oil circuit 6 and the second oil circuit 7, a second motor 51 for driving the replenishing pump 52, and a replenishing overflow valve 53 for adjusting the replenishing pressure. The replenishing pump assembly 5 can replenish the oil leaked from the flushing valve assembly 3, the closed pump assembly 2, and the hydraulic motor 4. The replenishing pump 52 is connected to the first oil circuit 6 and the second oil circuit 7 respectively through the replenishing oil circuit.

[0037] When the hydraulic closed system is ready to work, the second motor 51 is started first. The second motor 51 drives the oil replenishment pump 52 to run, and the oil replenishment circuit is filled with oil. The oil replenishment pressure is controlled by the oil replenishment overflow valve 53. Excess oil flows back to the oil tank through the oil replenishment overflow valve 53. The oil circuit pressure on both sides of the hydraulic closed system is the same as the oil replenishment pressure.

[0038] When the hydraulic closed system starts working, the first motor 21 is started, which drives the closed pump 22 to run. By increasing the displacement of the closed pump 22, the hydraulic motor 4 is rotated, which in turn drives the actuator. At this time, the oil inflow side of the hydraulic motor 4 is the high-pressure side oil circuit due to the load, and the oil outflow side is the low-pressure side oil circuit. At this time, the hydraulic control ports on both sides of the flushing shuttle valve 31 are activated by the pressure difference between the high and low pressure sides, which connects the flushing overflow valve 32 to the low-pressure side oil circuit of the hydraulic closed system, so that part of the low-pressure side oil flows back to the oil tank through the flushing overflow valve 32.

[0039] like Figure 1 and Figure 4 As shown, in this embodiment, the closed pump unit 2 also includes a replenishing check valve 23. The two replenishing check valves 23 are respectively arranged on the replenishing oil lines connected to the first oil line 6 and the second oil line 7 and the replenishing pump 52; they can ensure that the replenishing flow automatically replenishes the lower pressure side of the oil lines on both sides of the hydraulic closed system (the lower pressure side of the first oil line 6 and the second oil line 7).

[0040] like Figure 1 As shown, in this embodiment, a flushing valve assembly 3 is also included to allow a portion of the oil on the side with lower pressure in the first oil circuit 6 and the second oil circuit 7 to flow back to the oil tank. The two oil inlets of the flushing valve assembly 3 are connected to the first oil circuit 6 and the second oil circuit 7 respectively. By switching the flushing valve assembly 3, a portion of the oil on the side with lower pressure in the first oil circuit 6 and the second oil circuit 7 can flow back to the oil tank, which can remove heat and impurities from the hydraulic closed system.

[0041] like Figure 1 and Figure 5 As shown, in this embodiment, the flushing valve assembly 3 includes a flushing shuttle valve 31 and a flushing overflow valve 32. The two oil inlets of the flushing shuttle valve 31 are connected to the first oil circuit 6 and the second oil circuit 7, respectively. The oil outlet of the flushing shuttle valve 31 is connected to the oil tank through the flushing overflow valve 32. The hydraulic control ports on both sides of the flushing shuttle valve 31 are activated by the pressure difference between the first oil circuit 6 and the second oil circuit 7, connecting the flushing overflow valve 32 to the low-pressure side oil circuit of the hydraulic closed system (the side with the lower pressure in the first oil circuit 6 and the second oil circuit 7), so that part of the low-pressure side oil flows back to the oil tank through the flushing overflow valve 32. The flow rate can be adjusted by adjusting the pressure of the flushing overflow valve 32. Its structure is simple and can automatically switch directions according to the pressure difference between the first oil circuit 6 and the second oil circuit 7.

[0042] like Figure 1 and Figure 4As shown, in this embodiment, the closed pump unit 2 also includes a flushing damper 24 for controlling the flow rate of flushing the bearing and housing of the closed pump 22. The oil inlet of the flushing damper 24, the oil inlet of the two replenishing check valves 23 and the oil outlet of the replenishing pump 52 are connected. The oil outlet of the flushing damper 24 is connected to the oil tank. The flow rate of flushing the bearing and housing of the closed pump 22 can be controlled by the flushing damper 24.

[0043] In the existing hydraulic closed system, since it does not contain adaptive buffer valve group 1a and adaptive buffer valve group 1b, the high-pressure oil from the outlet of the closed pump 22 flows through the hydraulic motor 4 and returns to the inlet of the closed pump 22. When the load end driven by the hydraulic motor 4 has low inertia, the output end of the hydraulic motor 4 is subjected to sudden load impact, and the pressure of the high-pressure side oil circuit of the hydraulic closed system rises. Due to the effect of the elastic modulus of the hydraulic system (oil compression, pipeline expansion), the speed of the hydraulic motor 4 will decrease instantaneously. The return oil volume of the low-pressure side of the hydraulic motor 4 will be less than the oil output volume of the high-pressure side of the closed pump 22. When the replenishment flow of the replenishment pump group 5 is insufficient to make up for this flow difference, the low-pressure side pressure of the hydraulic closed system will drop rapidly or even suck in air, causing damage to the internal plunger structure of the closed pump 22 and the hydraulic motor 4, thereby affecting the service life.

[0044] Under a single impact, the flow difference that needs to be replenished on the low-pressure side of the hydraulic closed system can be calculated using the following formula:

[0045] Where: Q is the system replenishment oil flow rate; V is the total volume of oil on the high-pressure side; β e The equivalent bulk modulus of elasticity of the system;

[0046] △p / △t is the system pressure increase rate under impact; the total volume of oil on the high-pressure side and the equivalent volumetric elastic modulus of the system are difficult to change after the mechanism is determined. At the same time, since a large flow of oil is required only at the moment of impact, if the oil pump is increased, the flow of the oil pump will be lost through overflow most of the time, resulting in large energy loss and high cost.

[0047] Under the same conditions, when the hydraulic closed system contains adaptive buffer valve group 1a and adaptive buffer valve group 1b, the pressure shock of the high-pressure side oil circuit is greatly weakened, reducing the system pressure increase rate Δp / Δt under the shock, thereby significantly reducing the flow difference that needs to be added to the low-pressure side of the hydraulic closed system, avoiding the rapid decrease of pressure on the low-pressure side of the hydraulic closed system or even cavitation, and extending the service life of the system and its components.

[0048] like Figure 1 , Figure 2 and Figure 8As shown, when the hydraulic closed system encounters a jamming condition during operation, the hydraulic motor 4 is stuck and cannot rotate. After the high-pressure side of the system starts, the pressure rises directly from the replenishment pressure to the maximum pressure set by the pilot relief valve 11. The adaptive buffer valve group 1 has the same effect as the impact condition, allowing some oil from the high-pressure side to flow to the low-pressure side. The pressure impact on the high-pressure side is greatly reduced, preventing damage to the closed pump 22 and hydraulic motor 4 under frequent impact conditions, thus affecting their service life. It also prevents the system from overheating and wasting energy due to prolonged overflow. Furthermore, it reduces the system pressure increase rate Δp / Δt under impact, significantly reducing the flow difference that needs to be replenished on the low-pressure side of the hydraulic closed system. This prevents the low-pressure side pressure of the hydraulic closed system from dropping rapidly or even cavitating, extending the service life of the system and its components.

[0049] like Figure 1 , Figure 2 and Figure 9 As shown, when the hydraulic closed system encounters a start-up condition during operation, due to factors such as the inertia of the working mechanism and the conversion of dynamic and static friction, the initial load of the hydraulic motor 4 is relatively large, and the pressure on the high-pressure side of the system is relatively large at the moment of start-up. The effect of the adaptive buffer valve group 1 is basically the same as that of the impact condition. It can also make part of the oil in the high-pressure side oil circuit flow to the low-pressure side oil circuit. The pressure impact of the high-pressure side oil circuit is greatly weakened, avoiding damage to the closed pump 22 and hydraulic motor 4 under frequent impact conditions, thus affecting their service life. At the same time, the main valve core 16 gradually closes to prevent long-term overflow from causing system heat generation and energy waste. Furthermore, it reduces the system pressure increase rate Δp / Δt under impact, significantly reducing the flow difference that needs to be replenished on the low-pressure side of the hydraulic closed system, avoiding the rapid decrease or even cavitation of the low-pressure side pressure of the hydraulic closed system, and extending the service life of the system and its components.

[0050] A hydraulic device includes the aforementioned adaptive buffering hydraulic system under impact, which significantly reduces the pressure impact on the high-pressure side of the system when facing sudden load changes, jamming, or startup conditions. This prevents a rapid drop in pressure on the low-pressure side of the system, or even cavitation, extending the service life of the system and its components. Simultaneously, under non-impact conditions, the main valve core 16 can gradually close, preventing prolonged overflow from causing system overheating and energy waste. When the high-pressure side oil pressure continuously rises to the set pressure of the pilot relief valve 11, the main valve core 16 allows some oil from the high-pressure side to flow to the low-pressure side, protecting the high-pressure side pressure from exceeding the safety set value. Accumulators with different nitrogen charging pressures are connected for different pressure impact amplitudes, preventing excessive compression of the accumulator under high pressure. Optionally, the hydraulic device is construction machinery. Optionally, the construction machinery is a tunnel boring machine cutterhead, a screw conveyor, or a chain cutter continuous wall device. Optionally, the hydraulic device is mining machinery. Optionally, the mining machinery is a roadheader, etc. Optionally, the hydraulic equipment is agricultural machinery. Optionally, the agricultural machinery is a cotton harvester. Optionally, the hydraulic equipment is special-purpose machinery. Optionally, the special-purpose machinery is a snow blower.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydraulic system for adaptive buffering under impact, characterized in that, It includes a hydraulic motor (4) for driving the actuator, a closed pump group (2) for driving the hydraulic motor (4), a first oil passage (6) for connecting the oil outlet of the closed pump group (2) with the oil inlet of the hydraulic motor (4), a second oil passage (7) for connecting the oil outlet of the hydraulic motor (4) with the oil inlet of the closed pump group (2), and an adaptive buffer valve group (1) for weakening the pressure shock of the high-pressure side oil passage and preventing the low-pressure side oil passage from sucking in air. The oil inlets and outlets of the two adaptive buffer valve groups (1) are connected in parallel with the first oil passage (6) and the second oil passage (7) in opposite directions. The adaptive buffer valve assembly (1) includes a pilot relief valve (11), a first damper (12), a check valve (13), an accumulator (14), a second damper (15), and a main valve core (16). The oil outlet of the pilot relief valve (11) is connected to the oil outlet of the main valve core (16). The oil inlet of the pilot relief valve (11), the oil outlet of the first damper (12), the oil inlet of the check valve (13), the oil outlets of the accumulator (14), the second damper (15), and the first external control port of the main valve core (16) are connected. The first external control port of the main valve core (16) is arranged in the same way as the spring used to keep the main valve core (16) normally closed. On one side, the oil inlet of the first damper (12), the oil outlet of the one-way valve (13), the oil inlet of the second damper (15), the oil inlet of the main valve core (16), and the second external control port of the main valve core (16) are connected. The oil inlet of the main valve core (16) of one adaptive buffer valve group (1) is connected to the oil outlet of the closed pump group (2), and the oil outlet of the main valve core (16) is connected to the oil inlet of the closed pump group (2). The oil outlet of the main valve core (16) of another adaptive buffer valve group (1) is connected to the oil outlet of the closed pump group (2), and the oil inlet of the main valve core (16) is connected to the oil inlet of the closed pump group (2).

2. The hydraulic system for adaptive buffering under impact according to claim 1, characterized in that, The adaptive buffer valve group (1) includes a solenoid directional valve (19). Multiple accumulators (14) corresponding to different pressures are switched through the solenoid directional valve (19) and then connected to the first external control port of the main valve core (16).

3. The hydraulic system for adaptive buffering under impact according to any one of claims 1 or 2, characterized in that, The closed pump unit (2) includes a closed pump (22) and a first motor (21) for driving the closed pump (22).

4. The hydraulic system for adaptive buffering under impact according to claim 3, characterized in that, It also includes a replenishing pump assembly (5), which includes a replenishing pump (52) connected to the first oil circuit (6) and the second oil circuit (7), a second motor (51) for driving the replenishing pump (52), and a replenishing overflow valve (53) for adjusting the replenishing pressure.

5. The hydraulic system for adaptive buffering under impact according to claim 4, characterized in that, The closed-loop pump set (2) also includes a replenishing check valve (23), and the two replenishing check valves (23) are respectively arranged on the replenishing oil lines of the first oil line (6) and the second oil line (7) connected to the replenishing pump (52).

6. The hydraulic system for adaptive buffering under impact according to claim 3, characterized in that, It also includes a flushing valve assembly (3) for allowing a portion of the oil from the lower pressure side of the first oil passage (6) and the second oil passage (7) to flow back to the oil tank.

7. The hydraulic system for adaptive buffering under impact according to claim 6, characterized in that, The flushing valve assembly (3) includes a flushing shuttle valve (31) and a flushing overflow valve (32). The two oil inlets of the flushing shuttle valve (31) are connected to the first oil circuit (6) and the second oil circuit (7) respectively. The oil outlet of the flushing shuttle valve (31) is connected to the oil tank through the flushing overflow valve (32).

8. The hydraulic system for adaptive cushioning under impact according to claim 7, characterized in that, The closed pump unit (2) also includes a flushing damper (24) for controlling the flow rate of flushing the bearings and housing of the closed pump (22).

9. A hydraulic device, characterized in that, The hydraulic system comprising the adaptive cushioning under impact as described in any one of claims 1 to 8.

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