A low-load hydraulic system for an engine gear pump and piston variable pump

Abstract

This utility model relates to a low-load hydraulic system for an engine gear pump and plunger variable pump, comprising a power transmission (engine and transfer case linkage meshing shaft assembly), a pump assembly (3 gear pumps and 1 plunger pump), and a hydraulic control (tank, main controller, transmitter, butterfly valve) module. Power is transmitted through the meshing of the transfer case linkage shaft sleeve with the pump assembly transmission gears, and a stable seal is achieved with the help of the first / second connecting seats and multiple sealing rings. During startup, the plunger pump displacement is reduced to zero to decrease the load; after stabilization, the displacement is adjusted to coordinate fluid supply. The transmitter monitors for filter blockage and triggers an alarm, while the butterfly valve controls the oil circuit on / off protection system, achieving low-load startup, precise adjustment of excitation force, and long-term stable operation.

Description

Technical Field

[0001] This utility model specifically relates to a low-load hydraulic system for an engine gear pump plunger variable pump. Background Technology

[0002] Vibratory hammers are equipment specifically designed for pile driving, and the reliability and dynamic adjustment capability of their hydraulic systems directly affect operational efficiency and equipment lifespan. Currently, the hydraulic systems of vibratory hammers generally adopt a power configuration of "single engine linked with several fixed-displacement gear pumps"—the engine synchronously drives several fixed-displacement gear pumps through a transfer case, and utilizes the fixed proportional relationship between the output flow of the gear pumps and the engine speed to provide hydraulic power for actions such as clamping of the vibratory hammer's fixtures or output of excitation force.

[0003] Because vibratory hammer operations require frequent start-ups and shutdowns (such as when changing pile positions or adjusting pile driving angles), the engine must quickly enter high-load operation each time it is started. However, in existing technologies, a single engine needs to drive multiple gear pumps simultaneously. Insufficient circulation of lubricating oil within the engine leads to a surge in frictional resistance of mechanical components. At the same time, multiple fixed-displacement gear pumps need to output flow rates matching their rated speeds immediately upon startup, causing the engine to simultaneously overcome the dual pressures of "cold engine frictional resistance" and "multiple pump load torque." Traditional vibratory hammer engines are prone to insufficient starting speed, start-up failures, or even stalling (especially in low-temperature environments). Frequent restarts not only extend preparation time but may also interrupt operations due to start-up failures, severely impacting continuous operation capabilities. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an engine gear pump plunger variable pump low-load hydraulic system that addresses the shortcomings of the prior art. By setting an "adjustable displacement variable pump (such as a plunger pump)," the traditional method of simultaneous high-load operation of multiple fixed displacement pumps is changed, reducing the torque demand during engine start-up and effectively extending the service life of the engine.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a combined hydraulic system of engine linkage gear pump and piston variable pump to reduce starting load, characterized in that it includes a power transmission module, a pump group module, and a hydraulic control module, wherein the power transmission module and the hydraulic control module are respectively connected to the pump group module; The power transmission module includes an engine and a transfer case connected to the engine output end. The transfer case is equipped with a linkage engagement shaft assembly. The output shaft of the engine is linked with the linkage engagement shaft assembly of the transfer case. The linkage engagement shaft assembly of the transfer case is used to transmit the output force of the engine to the pump assembly module. The pump module includes several fixed displacement pumps that are respectively linked to the linkage engagement shaft group of the transfer case, and at least one variable displacement pump; the several fixed displacement pumps are used to provide hydraulic oil with a stable flow rate, and the at least one variable displacement pump is used to adjust the total flow rate of the combined hydraulic system; The hydraulic control module includes a hydraulic oil tank and a main control system. The hydraulic oil tank is connected to the inlet of several fixed-displacement pumps and at least one variable-displacement pump via oil pipes. The outlet of the several fixed-displacement pumps and at least one variable-displacement pump is connected to the inlet of the main control system.

[0006] Using the above technical solution, during engine startup, the linkage engagement shaft assembly in the transfer case synchronously drives the fixed displacement pump and the variable displacement pump. However, at this time, the displacement of the variable displacement pump is adjusted to 0, and only the fixed displacement pump operates under low load. The engine only needs to overcome the slight resistance of the fixed displacement pump to start. After the engine stabilizes, the hydraulic control module gradually increases the displacement of the variable displacement pump, so that it and the fixed displacement pump jointly output hydraulic oil to meet the flow requirements for actions such as clamping of the vibratory hammer fixture or output of excitation force. When the vibratory hammer needs to adjust the excitation force according to geological conditions, the main control system can change the total output flow (excitation force and flow are positively correlated) without changing the engine speed by adjusting the displacement knob of the variable displacement pump, thus achieving precise and rapid adjustment of the excitation force. In summary, by setting up an "adjustable displacement variable displacement pump (such as a plunger pump)," the traditional method of multiple fixed displacement pumps operating synchronously under high load is changed, reducing the torque requirement during engine startup and effectively extending the engine's service life. Meanwhile, by replacing the traditional method of engine speed regulation with "displacement adjustment of variable pump", the negative impact of speed fluctuations on engine life is avoided. This provides a faster and more effective solution for dynamic excitation force adjustment of vibratory hammers under complex geological conditions, improving the overall performance and maintenance costs of the equipment.

[0007] The aforementioned low-load hydraulic system for an engine gear pump plunger variable pump can be further configured as follows: the hydraulic control module also includes a transmitter and a butterfly valve. The butterfly valve and the transmitter are located between the hydraulic oil tank and several fixed displacement pumps and at least one variable displacement pump. The hydraulic oil tank is connected to the butterfly valve and the transmitter in sequence via oil pipes. The butterfly valve is connected to the oil inlet of several fixed displacement pumps and the oil inlet of at least one variable displacement pump via oil pipes. The transmitter is connected to the suction filter in the engine to monitor the blockage status of the suction filter and issue an alarm.

[0008] Using the above technical solution, before starting the vibratory hammer, the oil circuit between the hydraulic oil tank and the pump unit module is opened by opening the butterfly valve to ensure that the fixed displacement pump and variable displacement pump can normally draw in hydraulic oil. When the equipment needs to be shut down for maintenance or when a system abnormality is detected (such as pump unit overload), the butterfly valve can be closed to cut off the oil circuit, preventing the continuous flow of hydraulic oil from aggravating the fault. At the same time, the transmitter monitors the pressure difference change of the suction filter in real time. As the vibratory hammer operates for longer, the filter is gradually clogged by impurities, and the pressure difference gradually increases. When the pressure difference exceeds the set threshold, the transmitter triggers an alarm signal (such as a light prompt or buzzer), prompting timely replacement or cleaning of the filter to prevent the reduction of hydraulic oil flow (affecting the excitation force output) or impurities from entering the pump unit (aggravating component wear) due to clogging.

[0009] The aforementioned low-load hydraulic system for an engine gear pump and plunger variable pump can be further configured as follows: the variable pump is a plunger pump, the transfer case is provided with a first mounting hole, the linkage engagement shaft assembly includes a first linkage sleeve rotatably disposed at the first mounting hole, the end of the first linkage sleeve facing the plunger pump is provided with a first inner linkage hole, the inner circumferential surface of the first inner linkage hole is evenly distributed with first transmission meshing teeth, the output end of the plunger pump is provided with a plunger pump transmission gear inserted into the first inner linkage hole, and the plunger pump transmission gear is linked with the first linkage sleeve through the first transmission meshing teeth.

[0010] Using the above technical solution, the plunger pump can reduce engine load by zeroing displacement during startup and meet the dynamic flow requirements of the vibratory hammer by adjusting displacement during operation. The first mounting hole on the transfer case provides a fixed and rotatable mounting base for the first linkage sleeve, improving power transmission stability. The first linkage sleeve and the plunger pump drive gear are connected by inserting into the inner linkage hole, preventing radial offset or axial wobble of the plunger pump drive gear and ensuring smooth power transmission.

[0011] The aforementioned low-load hydraulic system for an engine gear pump and piston variable pump can be further configured as follows: a first connecting seat is provided between the piston pump and the transfer case. The first connecting seat includes a left support plate and a right support plate arranged sequentially along the axial direction of the first linkage sleeve. A support sleeve is provided between the left support plate and the right support plate. The two ends of the support sleeve are integrally formed with the left support plate and the right support plate, respectively. A first clearance through hole is provided in the first connecting seat, which passes through the left support plate, the support sleeve, and the right support plate in sequence. A plurality of first settling holes are provided on the right support plate. A set of first connecting holes is provided on the transfer case for each set of first settling holes. The first settling holes and the first connecting holes are connected by a first fastener. A plurality of second settling holes are provided on the left support plate. A set of second connecting holes is provided on the piston pump for each set of second settling holes. The second settling holes and the second connecting holes are connected by a second fastener.

[0012] Using the above technical solution, the first clearance through hole penetrates the left support plate, the support bushing, and the right support plate, providing interference-free axial space for the meshing transmission of the first linkage bushing and the plunger pump drive gear, ensuring smooth power transmission path. The first settling hole of the right support plate and the first connecting hole of the transfer case are rigidly connected by a first fastener (such as a bolt), enabling the connecting seat to be installed on the transfer case. The second settling hole of the left support plate and the second connecting hole of the plunger pump are connected by a second fastener (such as a bolt), enabling the plunger pump and the connecting seat to be securely installed, thereby keeping the first transmission meshing teeth of the plunger pump drive gear and the first linkage bushing coaxial, avoiding localized tooth wear or transmission jamming caused by installation deviation.

[0013] The aforementioned low-load hydraulic system for an engine gear pump and piston variable pump can be further configured as follows: the output end of the piston pump is provided with a first sealing ring, the left support plate is provided with a sealing hole sleeved on the outer periphery of the first sealing ring, the outer periphery of the first sealing ring is also provided with a first sealing ring distributed between the left support plate and the piston pump, a second sealing ring is provided in the sealing hole, and the two sides of the second sealing ring are respectively pressed against the end of the first sealing ring and the inner end face of the sealing hole.

[0014] Using the above technical solution, the first sealing ring is distributed between the left support plate and the plunger pump to prevent hydraulic oil from leaking radially or external dust and impurities from entering the transmission area; the second sealing ring is set in the sealing hole, with its two sides pressing against the end of the first sealing ring and the inner end face of the sealing hole respectively, forming a secondary seal through axial compression, effectively blocking the path of hydraulic oil penetration along the axis and improving the sealing performance.

[0015] The aforementioned low-load hydraulic system for an engine gear pump plunger variable pump can be further configured as follows: the fixed displacement pump is a gear pump; the transfer case is provided with a second mounting hole for each gear pump; the linkage engagement shaft assembly includes a second linkage sleeve rotatably disposed at the second mounting hole; the end of the second linkage sleeve facing the gear pump is provided with a second inner linkage hole; the inner circumferential surface of the second inner linkage hole is evenly distributed with second transmission meshing teeth; the output end of the gear pump is provided with a gear pump drive gear inserted into the second inner linkage hole; the gear pump drive gear is linked with the second linkage sleeve through the second transmission meshing teeth.

[0016] Using the above technical solution, the gear pump has a simple structure, low cost, and strong self-priming capability, providing a stable basic flow rate for the hydraulic system and meeting the basic hydraulic requirements of the vibratory hammer under normal operating conditions. The second mounting hole on the transfer case provides a rotatable mounting and positioning base for the second linkage sleeve, improving the stability of power transmission. The second linkage sleeve and the gear pump drive gear are connected by inserting into the inner linkage hole, preventing radial offset or axial wobble of the gear pump drive gear and ensuring smooth power transmission.

[0017] The aforementioned low-load hydraulic system for an engine gear pump plunger variable pump can be further configured as follows: a second connecting seat is provided between the gear pump and the transfer case. The second connecting seat is annular, and a second clearance through hole is provided in the middle of the second connecting seat. Several sets of third settling holes are provided on the second connecting seat. A set of fourth connecting holes is provided on the transfer case for each set of third settling holes. A set of fifth connecting holes is provided on the gear pump for each set of third settling holes. The third settling holes, fourth connecting holes, and fifth connecting holes are connected by a set of second fasteners.

[0018] Using the above technical solution, the second clearance through hole provides interference-free axial space for the meshing transmission of the second linkage bushing and the gear pump drive gear, ensuring the smoothness of the power transmission path. The third setter hole, the fourth connecting hole, and the fifth connecting hole are simultaneously connected by a set of second fasteners (such as bolts). This achieves a stable installation of the gear pump, the second connecting seat, and the transfer case, thereby keeping the second transmission meshing teeth of the gear pump drive gear and the second linkage bushing coaxial, avoiding localized tooth wear or transmission jamming caused by installation deviations.

[0019] The aforementioned low-load hydraulic system for an engine gear pump plunger variable pump can be further configured such that: the end face of the second connecting seat facing the gear pump is provided with an annular sealing groove, and a third sealing ring is provided in the annular sealing groove.

[0020] By adopting the above technical solution, oil leakage is avoided and a sealed connection between the gear pump and the second connecting seat is achieved.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the assembly of the gear pump, plunger pump, transfer case, and engine according to an embodiment of the present utility model; Figure 2 This is an exploded schematic diagram of the gear pump, plunger pump, and transfer case according to an embodiment of the present utility model; Figure 3 This is a schematic diagram of the system flow of an embodiment of the present utility model.

[0023] Label annotations: Engine 1; Transfer case 2, First mounting hole 2a, Second mounting hole 2b, Fourth connecting hole 2c; Gear pump 3, Gear pump drive gear 3a, Fifth connecting hole 3b; Piston pump 4, Piston pump drive gear 4a, Second connecting hole 4b, First sealing ring 4c; First linkage bushing 5, First transmission meshing teeth 5a; First connecting seat 6, Left support plate 6a, Right support plate 6b, Support bushing 6c, First clearance through hole 6d, First set hole 6e, Second set hole 6f, Sealing hole 6g, First sealing ring 6h, Second sealing ring 6i; Second linkage bushing 7, Second transmission meshing teeth 7a; Second connecting seat 8, Second clearance through hole 8a, Third set hole 8b, Annular sealing groove 8c, Third sealing ring 8d; Hydraulic oil tank 9, Main control system 10, Indicator 11, Butterfly valve 12. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] like Figures 1 to 3 The diagram shows a low-load hydraulic system consisting of an engine 1, a gear pump 3, a plunger pump 4, and a power transmission module, a pump assembly module, and a hydraulic control module. The power transmission module and the hydraulic control module are respectively connected to the pump assembly module.

[0026] The power transmission module includes an engine 1 and a transfer case 2 connected to the output end of the engine 1. The transfer case 2 is equipped with a linkage engagement shaft assembly. The output shaft of the engine 1 is linked with the linkage engagement shaft assembly of the transfer case 2. The linkage engagement shaft assembly of the transfer case 2 is used to transmit the output force of the engine 1 to the pump module.

[0027] The pump module includes three sets of gear pumps 3 and one set of plunger pumps 4, which are respectively linked to the linkage meshing shaft group of the transfer case 2. The three sets of gear pumps 3 are used to provide hydraulic oil with a stable flow rate, and the one set of plunger pumps 4 is used to regulate the total flow rate of the combined hydraulic system.

[0028] The transfer case 2 has a first mounting hole 2a. The linkage engagement shaft assembly includes a first linkage sleeve 5 rotatably mounted at the first mounting hole 2a. The end of the first linkage sleeve 5 facing the plunger pump 4 has a first inner linkage hole. The inner circumferential surface of the first inner linkage hole is evenly distributed with first transmission meshing teeth 5a. The output end of the plunger pump 4 has a plunger pump drive gear 4a inserted into the first inner linkage hole. The plunger pump drive gear 4a is linked with the first linkage sleeve 5 through the first transmission meshing teeth 5a. The plunger pump 4 can reduce the load on the engine 1 by zeroing the displacement during the start-up phase, and can meet the dynamic flow requirements of the vibratory hammer by adjusting the displacement during the operation phase. The first mounting hole 2a on the transfer case 2 provides a fixed and rotatable mounting base for the first linkage sleeve 5, improving the stability of power transmission. The first linkage sleeve 5 and the plunger pump drive gear 4a are connected by inserting into the inner linkage hole, which avoids radial offset or axial wobble of the plunger pump drive gear 4a and ensures smooth power transmission.

[0029] A first connecting seat 6 is also provided between the plunger pump 4 and the transfer case 2. The first connecting seat 6 includes a left support plate 6a and a right support plate 6b arranged sequentially along the axial direction of the first linkage sleeve 5. A support sleeve 6c is provided between the left support plate 6a and the right support plate 6b. The two ends of the support sleeve 6c are integrally formed with the left support plate 6a and the right support plate 6b, respectively. The first connecting seat 6 is provided with a first clearance through hole 6d that passes through the left support plate 6a, the support sleeve 6c, and the right support plate 6b in sequence. The right support plate 6b is provided with multiple sets of first settling holes 6e. The transfer case 2 is provided with a set of first connecting holes corresponding to each set of first settling holes 6e. The first settling holes 6e and the first connecting holes are connected by first fasteners. The left support plate 6a is provided with multiple sets of second settling holes 6f. The plunger pump 4 is provided with a set of second connecting holes 4b corresponding to each set of second settling holes 6f. The second settling holes 6f and the second connecting holes 4b are connected by second fasteners. The first clearance through hole 6d penetrates the left support plate 6a, the support bushing 6c, and the right support plate 6b, providing interference-free axial space for the meshing transmission of the first linkage bushing 5 and the plunger pump drive gear 4a, ensuring smooth power transmission. The first settling hole 6e of the right support plate 6b is rigidly connected to the first connecting hole of the transfer case 2 by a first fastener (such as a bolt), enabling the connecting seat to be installed on the transfer case 2. The second settling hole 6f of the left support plate 6a is connected to the second connecting hole 4b of the plunger pump 4 by a second fastener (such as a bolt), ensuring a stable installation of the plunger pump 4 and the connecting seat. This keeps the plunger pump drive gear 4a and the first transmission meshing teeth 5a of the first linkage bushing 5 coaxial, avoiding localized tooth wear or transmission jamming caused by installation deviations.

[0030] The output end of the plunger pump 4 is provided with a first sealing ring 4c. The left support plate 6a is provided with a sealing hole 6g that fits around the outer periphery of the first sealing ring 4c. A first sealing ring 6h is also provided around the outer periphery of the first sealing ring 4c, distributed between the left support plate 6a and the plunger pump 4. A second sealing ring 6i is provided inside the sealing hole 6g, with its two sides pressing against the end of the first sealing ring 4c and the inner end face of the sealing hole 6g, respectively. The first sealing ring 6h is distributed between the left support plate 6a and the plunger pump 4 to prevent hydraulic oil from leaking radially or external dust and impurities from entering the transmission area. The second sealing ring 6i is located inside the sealing hole 6g, with its two sides pressing against the end of the first sealing ring 4c and the inner end face of the sealing hole 6g, respectively. A secondary seal is formed through axial compression, effectively blocking the axial penetration path of hydraulic oil and improving sealing performance.

[0031] The transfer case 2 is provided with a second mounting hole 2b for each gear pump 3. The linkage engagement shaft assembly includes a second linkage sleeve 7 rotatably mounted at the second mounting hole 2b. The end of the second linkage sleeve 7 facing the gear pump 3 has a second inner linkage hole. The inner circumferential surface of the second inner linkage hole is evenly distributed with second transmission meshing teeth 7a. The output end of the gear pump 3 is provided with a gear pump drive gear 3a inserted into the second inner linkage hole. The gear pump drive gear 3a is linked with the second linkage sleeve 7 through the second transmission meshing teeth 7a. The gear pump 3 has a simple structure, low cost, and strong self-priming capability, and can provide a stable basic flow for the hydraulic system, meeting the basic hydraulic requirements of the vibratory hammer under normal operating conditions. The second mounting hole 2b on the transfer case 2 provides a rotatable mounting and positioning base for the second linkage sleeve 7, improving the stability of power transmission. The second linkage sleeve 7 and the gear pump drive gear 3a are connected by inserting into the inner linkage hole, avoiding radial offset or axial wobble of the gear pump drive gear and ensuring smooth power transmission.

[0032] A second connecting seat 8 is provided between the gear pump 3 and the transfer case 2. The second connecting seat 8 is annular, and a second clearance through hole 8a passes through the center of the second connecting seat 8. The second connecting seat 8 has multiple sets of third settling holes 8b. The transfer case 2 has a set of fourth connecting holes 2c corresponding to each set of third settling holes 8b. The gear pump 3 has a set of fifth connecting holes 3b corresponding to each set of third settling holes 8b. The third settling holes 8b, fourth connecting holes 2c, and fifth connecting holes 3b are connected by a set of second fasteners. The second clearance through hole 8a provides interference-free axial space for the meshing transmission of the second linkage sleeve 7 and the gear pump drive gear 3a, ensuring the smoothness of the power transmission path. The third settling holes 8b, fourth connecting holes 2c, and fifth connecting holes 3b are connected by a set of second fasteners (such as bolts). This ensures the stable installation of the gear pump 3, the second connecting seat 8, and the transfer case 2, thereby keeping the gear pump drive gear 3a and the second transmission meshing teeth 7a of the second linkage shaft sleeve coaxial, and avoiding local wear of the teeth or transmission jamming caused by installation deviation.

[0033] The second connecting seat 8 has an annular sealing groove 8c on its end face facing the gear pump 3, and a third sealing ring 8d is provided inside the annular sealing groove 8c. This prevents oil leakage and achieves a sealed connection between the gear pump 3 and the second connecting seat 8.

[0034] The hydraulic control module includes a hydraulic oil tank 9, a main control system 10, a transmitter 11, and a butterfly valve 12. The butterfly valve 12 and transmitter 11 are located between the hydraulic oil tank 9 and three sets of gear pumps 3 and one set of piston pumps 4. The hydraulic oil tank 9 is connected to the butterfly valve 12 and transmitter 11 sequentially via oil pipes. The butterfly valve 12 is connected to the inlet of the three sets of gear pumps 3 and the inlet of the one set of piston pumps 4 via oil pipes. The outlets of the three sets of gear pumps 3 and the one set of piston pumps 4 are connected to the inlet of the main control system 10. The transmitter 11 is connected to the suction filter in the engine 1 to monitor the filter's blockage status and trigger an alarm. The linkage engagement shaft assembly in the transfer case 2 synchronously drives the gear pumps 3 and piston pumps 4, but at this time, the displacement of piston pump 4 is adjusted to 0, and only gear pump 3 operates under low load. The engine 1 only needs to overcome the slight resistance of gear pump 3 to start. After engine 1 stabilizes, the hydraulic control module gradually increases the displacement of plunger pump 4, allowing it to output hydraulic oil together with gear pump 3 to meet the flow requirements for actions such as clamping or excitation force output of the vibratory hammer fixture. When the vibratory hammer needs to adjust the excitation force according to geological conditions, the main control system 10 can change the total output flow (excitation force and flow are positively correlated) without changing the engine speed by adjusting the displacement knob of plunger pump 4, achieving precise and rapid adjustment of the excitation force. In summary, by setting up an "adjustable displacement plunger pump 4 (e.g., plunger pump 4)," the traditional method of synchronous high-load operation of multi-gear pump 3 is changed, reducing the torque requirement during engine 1 startup and effectively extending the service life of engine 1. At the same time, by replacing the "traditional method of relying on engine 1 speed adjustment" with the "displacement adjustment of plunger pump 4," the negative impact of speed fluctuations on the life of engine 1 is avoided, providing a faster and more effective solution for dynamic excitation force adjustment of the vibratory hammer under complex geological conditions, improving the overall performance and maintenance costs of the equipment.

[0035] Working principle of this embodiment: First, when engine 1 starts, butterfly valve 12 is opened to connect the hydraulic oil tank 9 and the pump module. The linkage engagement shaft assembly of transfer case 2 synchronously drives gear pump 3 and piston pump 4 to operate. However, at this time, the displacement of piston pump 4 is adjusted to 0, and only gear pump 3 operates under low load. Engine 1 only needs to overcome the slight resistance of gear pump 3 to complete the start-up, reducing the torque requirement during the start-up phase. Second, after engine 1 runs stably, the hydraulic control module gradually increases the displacement of piston pump 4, so that it and gear pump 3 jointly output hydraulic oil to meet the flow requirements of actions such as clamping of vibratory hammer fixtures or output of excitation force. When it is necessary to adjust the excitation force according to geological conditions, the main control system 10 changes the total output flow (excitation force and flow are positively correlated) without changing the engine speed of engine 1 by adjusting the displacement knob of piston pump 4, thus achieving precise and rapid adjustment of the excitation force.

[0036] The transmitter 11 monitors the pressure difference of the suction filter in real time. When the pressure difference exceeds the set threshold due to impurities clogging the filter, it triggers an alarm (such as a light or buzzer) to prompt timely replacement or cleaning of the filter, preventing reduced flow (affecting the excitation force output) or impurities from entering the pump unit (aggravating component wear) due to clogging. When the equipment needs to be shut down for maintenance or a system abnormality is detected (such as pump unit overload), the butterfly valve 12 is closed to cut off the oil circuit, preventing the continuous flow of hydraulic oil from aggravating the fault.

Claims

1. A low-load hydraulic system for an engine gear pump plunger variable pump, characterized in that, It includes a power transmission module, a pump module, and a hydraulic control module, wherein the power transmission module and the hydraulic control module are respectively connected to the pump module; The power transmission module includes an engine and a transfer case connected to the engine output end. The transfer case is equipped with a linkage engagement shaft assembly. The output shaft of the engine is linked with the linkage engagement shaft assembly of the transfer case. The linkage engagement shaft assembly of the transfer case is used to transmit the output force of the engine to the pump assembly module. The pump module includes several fixed displacement pumps that are respectively linked to the linkage engagement shaft group of the transfer case, and at least one variable displacement pump; the several fixed displacement pumps are used to provide hydraulic oil with a stable flow rate, and the at least one variable displacement pump is used to adjust the total flow rate of the combined hydraulic system; The hydraulic control module includes a hydraulic oil tank and a main control system. The hydraulic oil tank is connected to the inlet of several fixed-displacement pumps and at least one variable-displacement pump via oil pipes. The outlet of the several fixed-displacement pumps and at least one variable-displacement pump is connected to the inlet of the main control system.

2. The low-load hydraulic system of engine gear pump plunger variable pump according to claim 1, characterized in that: The hydraulic control module also includes a transmitter and a butterfly valve. The butterfly valve and transmitter are located between the hydraulic oil tank and several fixed displacement pumps and at least one variable displacement pump. The hydraulic oil tank is connected to the butterfly valve and the transmitter in sequence through oil pipes. The butterfly valve is connected to the oil inlet of several fixed displacement pumps and the oil inlet of at least one variable displacement pump through oil pipes. The transmitter is connected to the oil suction filter in the engine to monitor the blockage status of the oil suction filter and issue an alarm.

3. A low-load hydraulic system for an engine gear pump plunger variable pump according to claim 1 or 2, characterized in that: The variable pump is a plunger pump. The transfer case is provided with a first mounting hole. The linkage engagement shaft assembly includes a first linkage sleeve rotatably disposed at the first mounting hole. The end of the first linkage sleeve facing the plunger pump is provided with a first inner linkage hole. The inner circumferential surface of the first inner linkage hole is evenly distributed with first transmission meshing teeth. The output end of the plunger pump is provided with a plunger pump transmission gear inserted into the first inner linkage hole. The plunger pump transmission gear is linked with the first linkage sleeve through the first transmission meshing teeth.

4. The low-load hydraulic system of engine gear pump plunger variable pump according to claim 3, characterized in that: A first connecting seat is provided between the plunger pump and the transfer case. The first connecting seat includes a left support plate and a right support plate arranged sequentially along the axial direction of the first linkage sleeve. A support sleeve is provided between the left support plate and the right support plate. The two ends of the support sleeve are integrally formed with the left support plate and the right support plate, respectively. The first connecting seat has a first clearance through hole that passes through the left support plate, the support sleeve, and the right support plate in sequence. The right support plate has several sets of first set holes. The transfer case has a set of first connecting holes corresponding to each set of first set holes. The first set holes and the first connecting holes are connected by a first fastener. The left support plate has several sets of second set holes. The plunger pump has a set of second connecting holes corresponding to each set of second set holes. The second set holes and the second connecting holes are connected by a second fastener.

5. A low-load hydraulic system for an engine gear pump and piston variable pump according to claim 4, characterized in that: The output end of the plunger pump is provided with a first sealing ring, and the left support plate is provided with a sealing hole fitted around the outer periphery of the first sealing ring. The outer periphery of the first sealing ring is also provided with a first sealing ring distributed between the left support plate and the plunger pump. A second sealing ring is provided inside the sealing hole, and the two sides of the second sealing ring are respectively pressed against the end of the first sealing ring and the inner end face of the sealing hole.

6. A low-load hydraulic system for an engine gear pump plunger variable pump according to claim 1 or 2, characterized in that: The metering pump is a gear pump. The transfer case is provided with a second mounting hole for each gear pump. The linkage engagement shaft assembly includes a second linkage sleeve rotatably disposed at the second mounting hole. The end of the second linkage sleeve facing the gear pump is provided with a second inner linkage hole. The inner circumferential surface of the second inner linkage hole is evenly distributed with second transmission meshing teeth. The output end of the gear pump is provided with a gear pump transmission gear inserted into the second inner linkage hole. The gear pump transmission gear is linked with the second linkage sleeve through the second transmission meshing teeth.

7. A low-load hydraulic system for an engine gear pump plunger variable pump according to claim 6, characterized in that: A second connecting seat is provided between the gear pump and the transfer case. The second connecting seat is annular and has a second clearance through hole in the middle. The second connecting seat is provided with several sets of third set holes. The transfer case is provided with a set of fourth connecting holes corresponding to each set of third set holes. The gear pump is provided with a set of fifth connecting holes corresponding to each set of third set holes. The third set holes, fourth connecting holes, and fifth connecting holes are connected by a set of second fasteners.

8. The low-load hydraulic system of engine gear pump plunger variable pump according to claim 7, characterized in that: The second connecting seat has an annular sealing groove on its end face facing the gear pump, and a third sealing ring is provided in the annular sealing groove.

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