A high power density double-head tandem integrated electric pump structure

Abstract

This invention discloses a high-power-density dual-head series integrated electric pump structure, belonging to the field of electric pumps. It includes a main shaft, a motor, and two plunger pumps. The main shaft serves as a drive shaft connecting the motor and the two plunger pumps to achieve torque transmission. The electric pump structure has one inlet and two outlets. The inlet is connected to an external oil supply device, and the outlets are connected to an external load. Each outlet is also connected to the oil outlet of one plunger pump. The inlet is connected to the suction port of each plunger pump via pipelines. Each pipeline is equipped with a cooling channel that communicates with the pipeline. The oil from the oil supply device enters the cooling channel to cool the stator of the motor. Two temperature sensors are evenly arranged circumferentially on the stator of the motor. The solenoid valve control system of the electric pump structure controls the opening of a solenoid valve based on the temperature feedback from each temperature sensor for temperature control regulation. This invention increases the output capacity of the electric pump structure and improves its power density.

Description

Technical Field

[0001] This invention belongs to the field of electric pumps, specifically relating to a high power density dual-head series integrated electric pump structure, which is suitable for high-efficiency power systems in aviation, aerospace and automotive industries. Background Technology

[0002] With the rapid development of electrification and distributed structures in aerospace, engineering machinery and other fields, electric pumps, as typical energy supply devices, are gradually replacing traditional centralized hydraulic systems and becoming one of the key energy conversion components due to their advantages such as fast response speed, high control precision, compact structure and easy integration.

[0003] Current electric pumps generally face a key bottleneck: under high-speed operation, to avoid excessive wear and cavitation risks, the pump head is typically designed with a small displacement structure, resulting in limited flow rate per unit power, which is insufficient to meet high flow rate requirements. There is an urgent need to propose a new configuration that, while maintaining the advantages of high speed and high integration of electric pumps, further increases their output capacity and power density to meet the needs of modern high-efficiency electric pumps. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a high power density dual-head series integrated electric pump structure.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention discloses a high power density dual-head series integrated electric pump structure. The device includes a housing and a drive motor, a main shaft, and two plunger pumps housed within the housing. The two plunger pumps are symmetrically arranged on both sides of the drive motor. The main shaft serves as a transmission shaft, connecting the drive motor and the two plunger pumps to transmit torque and speed. The swashplate of each plunger pump is located near the drive motor, and the swashplates of the two plunger pumps are tilted in the same direction. The electric pump structure has one inlet and two outlets. The inlet of the electric pump structure is connected to an external oil supply device, and the outlets are connected to an external load. Each plunger pump in the electric pump structure has a plunger pump chamber, and each plunger pump chamber is provided with an oil drain port. The stator of the drive motor is interference-fitted with the housing. Each outlet of the electric pump structure is connected to the oil outlet of a plunger pump, and the inlet of the electric pump structure is connected to the oil suction port of each plunger pump through pipelines. Each pipeline is equipped with a cooling channel connected to the pipeline. The cooling channel includes a first branch pipeline equipped with a solenoid valve and multiple second branch pipelines connected to the first branch pipeline. The outlet of the second branch pipeline is connected to the plunger pump chamber. The cooling channel is set on the housing, and the second branch pipelines are evenly arranged along the circumference of the housing. The oil from the oil supply device enters the cooling channel to cool the stator of the motor. The total flow rate of the oil in the cooling channel can be changed by adjusting the opening of the solenoid valve. Two temperature sensors are evenly arranged circumferentially on the stator of the motor to detect the temperature of the motor stator in real time. The temperature sensors feed back the detected temperature to the solenoid valve control system of the electric pump structure. The solenoid valve control system controls the opening of a solenoid valve according to the temperature feedback from each temperature sensor to adjust the flow rate of oil in the cooling channel, thereby controlling the temperature of the electric pump structure.

[0006] Furthermore, the rotor of the motor is fastened to the main shaft, which includes an outer bushing, an inner bushing, and a shaft core. All three bushings are open at both ends and hollow internally. The length of the shaft core is equal to the length of the inner bushing. The outer bushing includes a first shaft segment and a second shaft segment connected to each other. The diameter of the first shaft segment is smaller than that of the second shaft segment. Multiple through holes are evenly distributed circumferentially on the end face corresponding to the connection between the first and second shaft segments, allowing the hollow space in the main shaft to communicate with the plunger pump chamber. The inner bushing includes a third shaft segment and a fourth shaft segment connected to each other. The diameter of the third shaft segment is larger than that of the fourth shaft segment. The shaft diameter of the shaft segment is equal to that of the second shaft segment. The third shaft segment is completely fitted inside the second shaft segment. The end face corresponding to the connection between the third and fourth shaft segments has multiple through holes evenly arranged circumferentially. The shaft core includes a fifth, sixth, and seventh shaft segment that are connected to each other. The end face of the fifth shaft segment is tightly fitted with the end face of the outer shaft sleeve with through holes. The outer wall of the seventh shaft segment is tightly fitted with the inner wall of the inner shaft sleeve. The end face corresponding to the tight fit between the seventh shaft segment and the inner shaft sleeve has multiple through holes evenly arranged circumferentially. The fifth and sixth shaft segments do not contact the inner shaft sleeve, forming a cavity between the inner shaft sleeve and the shaft core.

[0007] Furthermore, the main shaft in the electric pump structure also has a main shaft chamber; one of the pipelines is also provided with a branch pipeline connected to the main shaft. The oil in the external oil supply device enters the main shaft through this branch pipeline, and then flows through the hollow space inside the outer bushing and the shaft core in sequence, before flowing out of the main shaft and into the main shaft chamber. Subsequently, the oil in the main shaft chamber flows back to the main shaft through the through hole of the shaft core, and then through the cavity between the inner bushing and the shaft core, and then through the through hole of the outer bushing into the plunger pump chamber, thereby cooling the rotor of the motor.

[0008] Secondly, the present invention also discloses a method of operating the electric pump structure described above, comprising: Connect the outlet of the electric pump structure to the external load, and connect the inlet of the electric pump structure to the external oil supply device. Start the drive motor, which drives the plunger pump through the main shaft. The plunger of the plunger pump reciprocates in the cylinder of the plunger pump. The oil in the oil supply device enters the plunger pump through the oil inlet of the plunger pump via the pipeline. After being compressed by the plunger, the oil is output through the oil outlet of the plunger pump and output to the external load through the outlet of the electric pump structure to drive the external load. When the plunger of the plunger pump is reciprocating, some oil enters the cooling channel and then enters the plunger pump chamber through the cooling channel. When the oil flows in the second branch pipeline, it will cool the stator of the motor. After the oil enters the plunger pump chamber, it can also cool the plunger pump. The oil can also leave the electric pump structure through the drain port. Meanwhile, the temperature sensor detects the temperature of the motor stator in real time and feeds the detected temperature back to the solenoid valve control system. The solenoid valve control system controls the opening of a solenoid valve based on the temperature feedback from each temperature sensor, and adjusts the oil flow to regulate the temperature.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a dual-head tandem structure where a single motor simultaneously drives two plunger pumps (left and right), significantly increasing the overall output flow rate of the electric pump structure. The integrated design, with the motor and plunger pumps sharing a common housing, drastically reduces system size and improves power density, making it particularly suitable for high-performance applications with extremely high space utilization requirements. The integrated cooling oil channel design significantly enhances the motor's heat dissipation efficiency, ensuring stable and reliable operation of the electric pump structure even under high power density conditions. The dual-variable mechanism design allows for synchronous adjustment of the displacement of the two plunger pumps, or independent control based on actual operating conditions and load requirements. Each pump displacement is adjusted to achieve more precise flow and pressure output control; a three-part main shaft is adopted to form an internal cooling circulation, improving cooling efficiency and reducing the overall weight of the electric pump; an intelligent cooling flow adjustment structure based on solenoid valve control is integrated, which can dynamically adjust the cooling oil flow according to parameters such as the real-time operating temperature and load status of the electric pump structure. When the load is low or the temperature rise is slow, the cooling flow will be automatically reduced to reduce energy consumption. Under high power and high temperature operating conditions, the cooling capacity will be rapidly improved, significantly improving the cooling channel response speed and thermal management efficiency, which helps the electric pump structure maintain better thermal stability and energy efficiency ratio. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the high power density dual-head series integrated electric pump structure according to an embodiment of the present invention; Figure 2 The housing in the embodiment of the present invention is Figure 1 Cross-sectional view of section AA; In the diagram: 1-Left housing; 2-Tail bearing; 3-Distributor plate; 4-Cylinder block; 5-Variable mechanism; 6-Plunger; 7-Slipper; 8-Swashplate; 9-Middle bearing; 10-Motor winding; 11-Motor stator core; 12-Temperature sensor; 13-Motor permanent magnet; 14-Right cooling pipe; 15-Right housing; 16-Left cooling pipe; 17-1 Outer bushing; 17-2 Inner bushing; 17-3 Shaft core; 18-Solenoid valve; 19-Pipe fitting; 20-Housing oil leak.

[0011] Figure 3 This is a schematic diagram of the end face of the outer shaft sleeve with a through hole in an embodiment of the present invention; Figure 4 This is a schematic diagram of the end face of the spindle core with a through hole in an embodiment of the present invention. Detailed Implementation

[0012] The present invention will be further described and illustrated below with reference to the accompanying drawings and 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 without conflict. To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0014] To address the shortcomings in output capacity of existing electric pump systems, this invention proposes a high-power-density dual-head series integrated electric pump structure. This structure employs a single motor to simultaneously drive two plunger pumps, thereby multiplying the overall pump output flow while maintaining high-speed motor operation. Furthermore, the motor and plunger pumps share a common housing design, maintaining a high degree of integration in the electric pump and significantly improving its power density.

[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0016] like Figure 1The above is a schematic diagram of the high power density dual-head series integrated electric pump structure involved in the present invention.

[0017] The high power density dual-head series integrated electric pump structure of the present invention has one inlet and two outlets. The inlet of the electric pump structure is connected to the outlet of an external oil supply device through a pipe joint 19, and the outlet of the electric pump structure is connected to the pipeline of an external load through a pipe joint 19.

[0018] The electric pump structure includes a housing, a drive motor, a main shaft, and two plunger pumps housed within the housing. The main shaft comprises three parts: an outer bushing 17-1, an inner bushing 17-2, and a shaft core 17-3. The two plunger pumps are symmetrically arranged on the left and right sides of the motor. The motor and plunger pumps share a housing, which includes a left housing 1 and a right housing 15. Multiple cooling pipes, designated as left cooling pipe 16 and right cooling pipe 14, are provided on the housing. The main shaft serves as a drive shaft connecting the motor and the two plunger pumps, transmitting torque and speed.

[0019] exist Figure 1 In the illustrated embodiment, the plunger pump is a swashplate axial plunger pump, which is a commercially available plunger pump. The swashplate axial plunger pump includes a swashplate 8, a slipper 7, a plunger 6, a cylinder block 4, a distributor plate 3, and a variable displacement mechanism 5. The plunger 6 is connected to the slipper 7 via a ball joint and is driven by the swashplate 8 to perform axial reciprocating motion, thus achieving the oil suction and discharge function. The swashplate 8 of each plunger pump is located near the motor, and the swashplates 8 of the two plunger pumps are tilted in the same direction. The variable displacement mechanisms 5 are respectively installed on the left housing 1 and the right housing 15. Each variable displacement mechanism 5 is used to independently adjust the displacement of one plunger pump, and they can also be linked to achieve synchronous variable displacement control.

[0020] The drive motor is located in the middle of the electric pump structure and adopts a permanent magnet synchronous motor structure. The drive motor includes a motor winding 10, a motor stator core 11, and a motor permanent magnet 13. The motor winding 10 and the motor stator core 11 constitute the motor stator, wherein the motor stator core 11 is interference-fitted with the housing and installed in the motor mounting slot inside the left housing 1, and is rigidly connected to it. The motor permanent magnet 13 constitutes the motor rotor and is installed in the middle of the main shaft. There is an air gap between the motor stator and the motor rotor. The electromagnetic torque generated between the motor stator and the motor rotor drives the plunger pump through the main shaft. In addition, two temperature sensors 12 are evenly arranged circumferentially on the motor stator, and the temperature sensors 12 are used to detect the temperature of the motor stator in real time.

[0021] Multiple tail-end bearings 2 and multiple mid-section bearings 9 are provided between the main shaft and the housing. The tail-end bearings 2 are located at both ends of the main shaft, meaning that both ends of the main shaft are supported by the tail-end bearings 2. The mid-section bearings 9 are located in the middle of the main shaft and at both ends of the drive motor, meaning that the middle of the main shaft is supported within the housing by mid-section bearings 9 symmetrically arranged on the left and right sides of the drive motor. In an embodiment of the present invention, the number of both tail-end bearings 2 and mid-section bearings 9 is four.

[0022] The intermediate bearing 9 adopts a sealed bearing or a sealed-bearing combination structure, which can isolate the electric pump structure to form a three-chamber structure, that is, the electric pump structure becomes a three-chamber structure consisting of a motor chamber and two plunger pump chambers. Each plunger pump chamber is equipped with an oil drain port, and a one-way valve is installed on the oil drain port.

[0023] exist Figure 1 In the illustrated embodiment, the main shaft is an assembly consisting of three parts: an outer bushing 17-1, an inner bushing 17-2, and a shaft core 17-3. The outer bushing 17-1, inner bushing 17-2, and shaft core 17-3 are all hollow structures. The outer bushing 17-1 externally houses the tail-end bearing 2, the plunger pump, the intermediate bearing 9, and the motor rotor. The shaft section housing the plunger pump has a smaller diameter, while the shaft section housing the intermediate bearing 9 and the motor rotor has a larger diameter. Multiple through holes are evenly distributed on the left end face of the larger diameter shaft section. Figure 3 As shown.

[0024] The inner bushing 17-2 has two sections with different diameters. The larger diameter section is embedded inside the larger diameter section of the outer bushing 17-1. The left end face of the inner bushing 17-2 is in close contact with the end face of the outer bushing 17-1 with a through hole, and there is no gap or leakage at the contact surface. The smaller diameter section of the inner bushing 17-2 is symmetrical to the smaller diameter section of the outer bushing, and a plunger pump and a tail end bearing 2 are installed on it.

[0025] The shaft core 17-3 is embedded inside the inner bushing 17-2. It has three shaft segments with different diameters. The end face of the leftmost shaft segment with the largest diameter fits tightly against the end face of the outer bushing 17-1 with a through hole and is welded together. The rightmost shaft segment of the shaft core 17-3 has a smaller diameter than the middle segment. The rightmost shaft segment fits tightly against the inner wall of the inner bushing 17-2. The end face of the rightmost shaft segment of the shaft core 17-3 has multiple evenly distributed through holes, such as... Figure 4 As shown; except for the outer circular surface of the right shaft section, the inner bushing 17-2 and the shaft core 17-3 are not in contact, and the cavity between them forms a flow channel. The left side of the flow channel is connected to the through hole on the end face of the outer bushing 17-1, and the right side is connected to the through hole on the end face of the shaft core 17-3.

[0026] The branch from the left housing to the end of the main shaft introduces oil into the internal flow channel of the main shaft. The oil flows in from the internal channel of the small diameter section of the outer bushing, enters the internal channel of the shaft core, flows out from the right side of the shaft core, and then enters the cavity between the shaft core and the inner bushing through the evenly distributed through holes on the right end face of the shaft core. Finally, it flows out from the evenly distributed through holes on the end face of the outer bushing into the plunger pump chamber, and finally flows out of the electric pump structure through the oil leakage port 20 of the housing, forming an internal cooling circulation oil circuit to cool the rotor inside the motor.

[0027] like Figure 1 As shown, cooling channels extend from the oil inlets of the left and right plunger pumps. After passing through the left and right solenoid valves 18, each channel branches into four second branch pipes. These second branch pipes flow through the housing area surrounding the stator to cool it. The second branch pipes are designed in a serpentine flow pattern to increase the heat exchange area and reduce the heat exchange time. Oil entering the electric pump structure from the outside enters the left and right cooling pipes, absorbs heat in the stator core 11 area, and then flows back to the plunger pump chamber, returning to the oil tank along with the return oil from the plunger pump, forming a cooling cycle. Specifically, the oil in each cooling pipe flows inside the housing through the plunger pump, the intermediate bearing, and the motor stator. Then, at the end of the motor stator, the flow channel turns inward, flowing again through the motor stator and the intermediate bearing. Near the intermediate bearing, it flows into the plunger pump chamber through a housing hole and then out of the electric pump structure through the plunger pump chamber's housing drain port 20, returning to the external oil tank.

[0028] Among them, part of the pipeline connecting the inlet of the electric pump structure to the oil suction port of the right plunger pump is located outside the housing. In the pipeline connecting the inlet of the electric pump structure to the oil suction port of the right plunger pump, the part of the pipeline located outside the housing is connected to the part of the pipeline located outside the housing through pipe joint 19.

[0029] Temperature sensor 12 feeds back the detected temperature to the solenoid valve control system of the electric pump structure. The solenoid valve control system controls the opening of a solenoid valve 18 according to the temperature fed back by each temperature sensor 12. By adjusting the opening of the solenoid valve, the total flow rate of oil in the cooling channel can be changed, thereby controlling the temperature of the electric pump structure.

[0030] like Figure 1As shown, inside the electric pump structure, each outlet of the electric pump structure is connected to the oil outlet on the distribution plate 3 of the plunger pump through a flow channel on the housing; simultaneously, the oil inlets of the distribution plates 3 of the two plunger pumps extend into inlet pipe joints. The inlet pipe joint of the electric pump structure is a three-way structure, connecting to the external oil supply device, the oil inlet of the left plunger pump, and the oil inlet of the right plunger pump, respectively. The flow channel between the inlet of the electric pump structure and the oil inlet of the left plunger pump has two branches, one leading to the end of the main shaft and the other leading to the oil inlet of the solenoid valve 18 located on the left; the flow channel between the inlet of the electric pump structure and the oil inlet of the left plunger pump has only one branch, leading to the oil inlet of the solenoid valve 18 located on the right.

[0031] Each outlet of the electric pump structure is connected to the oil outlet of a plunger pump, and the inlet of the electric pump structure is connected to the oil suction port of each plunger pump via pipelines. Each pipeline is equipped with a cooling channel, which includes a first branch pipeline equipped with a solenoid valve 18 and multiple second branch pipelines connected to the first branch pipeline. The outlet of each second branch pipeline is connected to the plunger pump chamber. The cooling channels are located on the housing, and the second branch pipelines are evenly distributed along the circumference of the housing. The oil from the oil supply device enters the cooling channels to cool the stator of the motor. The flow rate of the oil in the cooling channels can be changed by adjusting the opening of the solenoid valve 18.

[0032] The first branch pipe and a second branch pipe together form a cooling pipe circuit. Figure 2 In the illustrated embodiment, there are four left cooling pipes 16 and four right cooling pipes 14. The cooling pipe located on the right housing 15 is the right cooling pipe 14, and the cooling pipe located on the left housing 1 is the left cooling pipe 16. Figure 2 As shown, there are 8 cooling pipes in the AA section of the shell. The cooling flow of 4 of them is regulated by a solenoid valve located on the left side of the electric pump structure, and the remaining 4 are regulated by a solenoid valve located on the right side of the electric pump structure.

[0033] In this invention Figure 1 In the embodiment shown, the outlet of the second branch of the left cooling pipe 16 is connected to the plunger pump chamber located on the left side of the electric pump structure; the outlet of the second branch of the right cooling pipe 14 is connected to the plunger pump chamber located on the right side of the electric pump structure.

[0034] In this invention, the solenoid valve control system controls the opening degree of one solenoid valve based on the temperature feedback from each temperature sensor, including: Each temperature sensor every The temperature of the motor stator is collected once per time interval, and i (i≥5) temperature data points are continuously retained. The time point of the k-th time to collect the motor stator temperature is... : , The time of the first acquisition of the motor stator temperature is [time value], and the temperature corresponding to the kth acquisition of the motor stator temperature is [temperature value]. .

[0035] Based on the retained temperature data, a polynomial method was used to fit the temperature-time curve, assuming that the temperature changes with time (i.e., the temperature-time curve) as follows: group i Substitute the temperature-time curve to construct a system of equations: Calculate , and The temperature-time curve can then be obtained. ; Calculations show that the preset limit temperature has been reached. Time required :make = Substituting the equation into the temperature-time curve yields the following equation. Solving for the required time , .

[0036] Let the opening degree of the solenoid valve be K, expressed as a percentage, and define the minimum opening degree. Ensure the drive motor's unloaded foundation heat dissipation to avoid zero cooling flow; define the maximum opening degree. Shortest warning time Longest basic heat dissipation time , .

[0037] The opening degree of the solenoid valve is actively controlled in three intervals: like ,but ; like ,but ; like ,but . The solenoid valve adjusts its opening according to this command, thereby precisely controlling the flow rate of cooling oil through the housing of the electric pump structure and changing the heat dissipation efficiency of the motor. This adjustment process continues continuously, forming a closed loop of measurement-comparison-calculation-execution-feedback, so that the actual temperature of the drive motor does not exceed the preset limit temperature.

[0038] In a preferred embodiment of the present invention, a method of operating the electric pump structure includes: Connect the outlet of the electric pump structure to the external load, and connect the inlet of the electric pump structure to the external oil supply device. Start the drive motor, which drives the plunger pump through the main shaft. The plunger of the plunger pump reciprocates in the cylinder of the plunger pump. The oil in the oil supply device enters the plunger pump through the oil inlet of the plunger pump via the pipeline. After being compressed by the plunger, the oil in the plunger pump is output through the oil outlet of the plunger pump and output to the external load through the outlet of the electric pump structure to drive the external load. When the plunger of the plunger pump is reciprocating, some oil enters the branch pipe and enters the plunger pump chamber through the cooling channel. When the oil flows in the second branch pipe, it will cool the stator of the motor. After the oil enters the plunger pump chamber, it can also cool the plunger pump. The oil can also leave the electric pump structure through the drain port. At the same time, the temperature sensor 12 detects the temperature of the motor stator in real time and feeds back the detected temperature to the solenoid valve control system. The solenoid valve control system controls the opening of a solenoid valve 18 according to the temperature fed back by each temperature sensor 12, and adjusts the temperature by regulating the flow of oil.

[0039] The electric pump structure proposed in this invention improves its output capacity by connecting two plunger pumps, left and right, in series. The two outlets of the electric pump structure can drive a load in parallel or drive different loads separately. The left and right plunger pumps can work independently or output in parallel, realizing high-flow oil supply or redundant switching, thereby improving the applicability and safety of the electric pump structure.

[0040] The electric pump structure proposed in this invention adopts a common housing design, integrating the motor and left and right plunger pumps onto a single housing. Considering manufacturing processes, the housing can also be a split structure with left and right housings. The housing is divided into a three-chamber structure via the main shaft, the middle bearing 9, and the tail bearing 2, comprising a motor chamber and two plunger pump chambers. The middle motor chamber is not filled with oil, while the left and right plunger pump chambers are filled with return oil. The oil drain ports of the plunger pump chambers are connected to the oil tank, effectively preventing the motor from being contaminated by oil and improving the cleanliness and reliability of the electric pump structure.

[0041] The electric pump structure described in this invention employs a main shaft composed of three parts, with an internal circulating cooling oil circuit for efficient cooling of the pump's core. In addition, multiple cooling channels are provided on the housing to form efficient heat dissipation pathways near the motor stator area. Cooling oil is introduced near the left and right inlets of these channels, and after being regulated by left and right solenoid valves, it branches into four second branch pipes, which enter the left and right cooling pipes respectively. After absorbing heat in the motor stator area, the oil flows back to the plunger pump chamber and returns to the oil tank along with the return oil, forming a cooling cycle. The opening of the solenoid valves is monitored in real-time by a temperature sensor, and the temperature is fed back for control, allowing for on-demand adjustment of the cooling flow rate to ensure the motor's thermal stability and maintain reliable operation under high power density conditions.

[0042] In summary, this implementation scheme achieves coordinated operation of dual plunger pumps under the drive of a single motor through a symmetrical arrangement of "one motor and two pump heads," significantly improving the hydraulic output capacity per unit volume. Furthermore, through integrated cooling channel design and a three-chamber isolation structure, it effectively enhances the overall cooling performance and the structural reliability of the electric pump. The combination of hollow shaft cooling and intelligent multi-branch shell cooling achieves efficient and reliable thermal management, demonstrating promising prospects for engineering applications.

[0043] This invention achieves a compact and highly integrated design through component layout and flow channel distribution within a limited volume, significantly saving installation space. The main shaft, designed with internal cooling oil channels, is composed of three parts, achieving efficient core cooling. Simultaneously, an active thermal management system is configured. Based on motor temperature detection, it predicts the time it takes for the motor to reach its critical temperature and, combined with cooling efficiency, calculates the required cooling flow rate. The system dynamically adjusts the oil cooling flow rate introduced from the inlet via solenoid valves on the cooling channels. When the temperature is low, the cooling flow rate is reduced, avoiding cavitation problems caused by insufficient inlet flow and reducing power waste. Balancing space utilization and thermal management efficiency, this design is suitable for fluid transport scenarios with high requirements for volume and reliability.

[0044] All matters not covered in this invention are common knowledge.

[0045] 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 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. A high power density dual head in-line integrated electric pump structure, characterized by, The device includes a housing and a drive motor, a main shaft, and two plunger pumps housed within the housing. The two plunger pumps are symmetrically arranged on both sides of the drive motor. The main shaft serves as a transmission shaft, connecting the drive motor and the two plunger pumps to transmit torque and speed. The swashplate of each plunger pump is located near the drive motor, and the swashplates of the two plunger pumps are tilted in the same direction. The electric pump structure has one inlet and two outlets. The inlet of the electric pump structure is connected to an external oil supply device, and the outlets are connected to an external load. Each plunger pump in the electric pump structure has a plunger pump chamber, and each plunger pump chamber is provided with an oil drain port. The stator of the drive motor is interference-fitted with the housing. Each outlet of the electric pump structure is connected to the oil outlet of a plunger pump, and the inlet of the electric pump structure is connected to the oil suction port of each plunger pump through pipelines. Each pipeline is equipped with a cooling channel connected to the pipeline. The cooling channel includes a first branch pipeline equipped with a solenoid valve and multiple second branch pipelines connected to the first branch pipeline. The outlet of the second branch pipeline is connected to the plunger pump chamber. The cooling channel is set on the housing, and the second branch pipelines are evenly arranged along the circumference of the housing. The oil from the oil supply device enters the cooling channel to cool the stator of the motor. The total flow rate of the oil in the cooling channel can be changed by adjusting the opening of the solenoid valve. Two temperature sensors are evenly arranged circumferentially on the stator of the motor to detect the temperature of the motor stator in real time. The temperature sensors feed back the detected temperature to the solenoid valve control system of the electric pump structure. The solenoid valve control system controls the opening of a solenoid valve according to the temperature feedback from each temperature sensor to adjust the flow rate of oil in the cooling channel, thereby controlling the temperature of the electric pump structure.

2. The high power density double head series integrated electric pump structure according to claim 1, characterized in that, The rotor of the motor is fastened to the main shaft. The main shaft includes an outer bushing, an inner bushing, and a shaft core. All three bushings are open at both ends and hollow internally. The length of the shaft core is equal to the length of the inner bushing. The outer bushing includes a first shaft segment and a second shaft segment connected to each other. The diameter of the first shaft segment is smaller than the diameter of the second shaft segment. Multiple through holes are evenly distributed circumferentially on the end face corresponding to the connection between the first and second shaft segments, allowing the hollow space in the main shaft to communicate with the plunger pump chamber. The inner bushing includes a third shaft segment and a fourth shaft segment connected to each other. The diameter of the third shaft segment is larger than that of the fourth shaft segment. The shaft diameter is such that the length of the third shaft segment is equal to that of the second shaft segment, and the third shaft segment is completely fitted inside the second shaft segment. Multiple through holes are evenly distributed circumferentially on the end face corresponding to the connection between the third and fourth shaft segments. The shaft core includes interconnected fifth, sixth, and seventh shaft segments. The end face of the fifth shaft segment is tightly fitted to the end face of the outer shaft sleeve with through holes, and the outer wall of the seventh shaft segment is tightly fitted to the inner wall of the inner shaft sleeve. Multiple through holes are evenly distributed circumferentially on the end face corresponding to the tight fit between the seventh shaft segment and the inner shaft sleeve. Neither the fifth nor the sixth shaft segment contacts the inner shaft sleeve, forming a cavity between the inner shaft sleeve and the shaft core.

3. The high power density double head series integrated electric pump structure according to claim 2, characterized in that, The main shaft in the electric pump structure also has a main shaft chamber; One of the pipelines is also provided with a branch pipeline connected to the main shaft. The oil in the external oil supply device enters the main shaft through this branch pipeline, then flows through the hollow space inside the outer bushing and the shaft core, and then flows out of the main shaft into the main shaft chamber. Subsequently, the oil in the main shaft chamber flows back to the main shaft through the through hole of the shaft core, and then through the cavity between the inner bushing and the shaft core, and then through the through hole of the outer bushing into the plunger pump chamber, thereby cooling the rotor of the motor.

4. The high power density dual head in-line integrated electric pump structure of claim 1, wherein, The solenoid valve control system controls the opening degree of one solenoid valve based on the temperature feedback from each temperature sensor, including: Every temperature sensor collects the temperature of the motor stator once every Collect the temperature of the motor stator once every second and continuously keep i temperature data, where i≥5. The temperature-time curve is Substitute the i temperature data points and the corresponding time into the temperature-time curve, and solve for the... , and The temperature-time curve was obtained. ; Then, based on the temperature-time curve, the preset limit temperature is calculated. Time required , ; like Then the current opening degree of the solenoid valve is the preset minimum opening degree. ;like Then the current opening degree of the solenoid valve is the preset maximum opening degree. ;like Then the current opening degree of the solenoid valve is ;in, This is the preset maximum basic heat dissipation time. This is the preset minimum warning time.

5. The high power density dual-head series integrated electric pump structure according to claim 1, characterized in that, Multiple tail-end bearings and multiple mid-section bearings are provided between the main shaft and the housing. The tail-end bearings are located at both ends of the main shaft, and the mid-section bearings are located in the middle of the main shaft and at both ends of the drive motor. The intermediate bearing adopts a sealed bearing or a sealed-bearing combination structure, making the electric pump structure a three-chamber structure consisting of a drive motor chamber and two plunger pump chambers.

6. The high power density dual-head series integrated electric pump structure according to claim 1, characterized in that, The drive motor is a permanent magnet synchronous motor; the plunger pump is an axial plunger pump.

7. The high power density dual-head series integrated electric pump structure according to claim 1, characterized in that, The electric pump structure also includes two variable displacement mechanisms, which are mounted on the housing. Each variable displacement mechanism is used to independently adjust the displacement of a plunger pump.

8. The high power density dual-head series integrated electric pump structure according to claim 1, characterized in that, A one-way valve is installed on the oil drain port.

9. The high power density dual-head series integrated electric pump structure according to claim 1, characterized in that, The two outlets of the electric pump structure are connected in parallel to the same load or each outlet is connected to a separate load.

10. A method of operating the electric pump structure according to claim 1, characterized in that, include: Connect the outlet of the electric pump structure to the external load, and connect the inlet of the electric pump structure to the external oil supply device. Start the drive motor, which drives the plunger pump through the main shaft. The plunger of the plunger pump reciprocates in the cylinder of the plunger pump. The oil in the oil supply device enters the plunger pump through the oil inlet of the plunger pump via the pipeline. After being compressed by the plunger, the oil is output through the oil outlet of the plunger pump and output to the external load through the outlet of the electric pump structure to drive the external load. When the plunger of the plunger pump is reciprocating, some oil enters the cooling channel and then enters the plunger pump chamber through the cooling channel. When the oil flows in the second branch pipeline, it will cool the stator of the motor. After the oil enters the plunger pump chamber, it can also cool the plunger pump. The oil can also leave the electric pump structure through the drain port. Meanwhile, the temperature sensor detects the temperature of the motor stator in real time and feeds the detected temperature back to the solenoid valve control system. The solenoid valve control system controls the opening of a solenoid valve based on the temperature feedback from each temperature sensor, and adjusts the oil flow to regulate the temperature.

Images